TY - CHAP A1 - Abendschein, Robin A1 - Desai, Shital A1 - Astell, Arlene J. T1 - Towards Accessibility Guidelines for the Metaverse : A Synthesis of Recommendations for People Living With Dementia T2 - Conference on Human Factors in Computing Systems (CHI’23) : Workshop "Towards an Inclusive and Accessible Metaverse" N2 - Given the growing interest of corporate stakeholders in Metaverse applications, there is a need to understand accessibility of these technologies for marginalized populations such as people living with dementia to ensure inclusive design of Metaverse applications. We assessed the accessibility of extended reality technology for people living with mild cognitive impairment and dementia to develop accessibility guidelines for these technologies. We used four strategies to synthesize evidence for barriers and facilitators of accessibility: (1) Findings from a non-systematic literature review, (2) guidelines from well-researched technology, (3) exploration of selected mixed reality technologies, and (4) observations from four sessions and video data of people living with dementia using mixed reality technologies. We utilized template analysis to develop codes and themes towards accessibility guidelines. Future work can validate our preliminary findings by applying them on video recordings or testing them in experiments. KW - CHI Conference KW - Accessibility KW - Metaverse KW - extended reality KW - dementia KW - cognitive impairment KW - Human-centered computing / Access KW - Human-centered computing / Human computer interaction (HCI) / Interaction paradigms / Mixed / augmented reality KW - Human-centered computing / Human computer interaction (HCI) / Interaction paradigms / Virtual reality KW - Human-centered computing / Human computer interaction (HCI) / Interactiondevices KW - Human-centered computing / Human computerinteraction (HCI) / Interaction techniques Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-320199 UR - https://sites.google.com/view/accessiblemetaverse ER - TY - RPRT A1 - Alfredsson, Rebecka A1 - Kassler, Andreas A1 - Vestin, Jonathan A1 - Pieska, Marcus A1 - Amend, Markus T1 - Accelerating a Transport Layer based 5G Multi-Access Proxy on SmartNIC T2 - Würzburg Workshop on Next-Generation Communication Networks (WueWoWas'22) N2 - Utilizing multiple access technologies such as 5G, 4G, and Wi-Fi within a coherent framework is currently standardized by 3GPP within 5G ATSSS. Indeed, distributing packets over multiple networks can lead to increased robustness, resiliency and capacity. A key part of such a framework is the multi-access proxy, which transparently distributes packets over multiple paths. As the proxy needs to serve thousands of customers, scalability and performance are crucial for operator deployments. In this paper, we leverage recent advancements in data plane programming, implement a multi-access proxy based on the MP-DCCP tunneling approach in P4 and hardware accelerate it by deploying the pipeline on a smartNIC. This is challenging due to the complex scheduling and congestion control operations involved. We present our pipeline and data structures design for congestion control and packet scheduling state management. Initial measurements in our testbed show that packet latency is in the range of 25 μs demonstrating the feasibility of our approach. KW - Datennetz KW - multipath KW - MP-DCCP KW - 5G-ATSSS KW - networking KW - dataplane programming KW - P4 Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-280798 ER - TY - JOUR A1 - Ali, Qasim A1 - Montenegro, Sergio T1 - Decentralized control for scalable quadcopter formations JF - International Journal of Aerospace Engineering N2 - An innovative framework has been developed for teamwork of two quadcopter formations, each having its specified formation geometry, assigned task, and matching control scheme. Position control for quadcopters in one of the formations has been implemented through a Linear Quadratic Regulator Proportional Integral (LQR PI) control scheme based on explicit model following scheme. Quadcopters in the other formation are controlled through LQR PI servomechanism control scheme. These two control schemes are compared in terms of their performance and control effort. Both formations are commanded by respective ground stations through virtual leaders. Quadcopters in formations are able to track desired trajectories as well as hovering at desired points for selected time duration. In case of communication loss between ground station and any of the quadcopters, the neighboring quadcopter provides the command data, received from the ground station, to the affected unit. Proposed control schemes have been validated through extensive simulations using MATLAB®/Simulink® that provided favorable results. KW - scalable quadcopter Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-146704 VL - 2016 ER - TY - JOUR A1 - Ali, Qasim A1 - Montenegro, Sergio T1 - Explicit Model Following Distributed Control Scheme for Formation Flying of Mini UAVs JF - IEEE Access N2 - A centralized heterogeneous formation flight position control scheme has been formulated using an explicit model following design, based on a Linear Quadratic Regulator Proportional Integral (LQR PI) controller. The leader quadcopter is a stable reference model with desired dynamics whose output is perfectly tracked by the two wingmen quadcopters. The leader itself is controlled through the pole placement control method with desired stability characteristics, while the two followers are controlled through a robust and adaptive LQR PI control method. Selected 3-D formation geometry and static stability are maintained under a number of possible perturbations. With this control scheme, formation geometry may also be switched to any arbitrary shape during flight, provided a suitable collision avoidance mechanism is incorporated. In case of communication loss between the leader and any of the followers, the other follower provides the data, received from the leader, to the affected follower. The stability of the closed-loop system has been analyzed using singular values. The proposed approach for the tightly coupled formation flight of mini unmanned aerial vehicles has been validated with the help of extensive simulations using MATLAB/Simulink, which provided promising results. KW - quadcopter KW - robustness KW - intelligent vehicles KW - rotors KW - mathematical model KW - aerodynamics KW - adaptation models KW - vehicle dynamics KW - unmanned aerial vehicle KW - distributed control KW - formation flight KW - model following Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-146061 N1 - (c) 2016 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works VL - 4 IS - 397-406 ER - TY - CHAP A1 - Ali, Qasim A1 - Montenegro, Sergio T1 - A Simple Approach to Quadrocopter Formation Flying Test Setup for Education and Development T2 - INTED2015 Proceedings N2 - A simple test setup has been developed at Institute of Aerospace Information Technology, University of Würzburg, Germany to realize basic functionalities for formation flight of quadrocopters. The test environment is planned to be utilized for developing and validating the algorithms for formation flying capability in real environment as well as for education purpose. An already existing test bed for single quadrocopter was extended with necessary inter-communication and distributed control mechanism to test the algorithms for formation flights in 2 degrees of freedom (roll / pitch). This study encompasses the domain of communication, control engineering and embedded systems programming. Bluetooth protocol has been used for inter-communication between two quadrocopters. A simple approach of PID control in combination with Kalman filter has been exploited. MATLAB Instrument Control Toolbox has been used for data display, plotting and analysis. Plots can be drawn in real-time and received information can also be stored in the form of files for later use and analysis. The test setup has been developed indigenously and at considerably low cost. Emphasis has been placed on simplicity to facilitate students learning process. Several lessons have been learnt during the course of development of this setup. Proposed setup is quite flexible that can be modified as per changing requirements. KW - Flugkörper KW - Design and Development KW - Formation Flight KW - Instrument Control Toolbox KW - Quadrocopter KW - Unmanned Aerial Vehicle KW - Quadrocopter Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-114495 SN - 978-84-606-5763-7 SN - 2340-1079 SP - 2776 EP - 2784 PB - International Academy of Technology, Education and Development (IATED) ER - TY - JOUR A1 - Andronic, Joseph A1 - Shirakashi, Ryo A1 - Pickel, Simone U. A1 - Westerling, Katherine M. A1 - Klein, Teresa A1 - Holm, Thorge A1 - Sauer, Markus A1 - Sukhorukov, Vladimir L. T1 - Hypotonic Activation of the Myo-Inositol Transporter SLC5A3 in HEK293 Cells Probed by Cell Volumetry, Confocal and Super-Resolution Microscopy JF - PLoS One N2 - Swelling-activated pathways for myo-inositol, one of the most abundant organic osmolytes in mammalian cells, have not yet been identified. The present study explores the SLC5A3 protein as a possible transporter of myo-inositol in hyponically swollen HEK293 cells. To address this issue, we examined the relationship between the hypotonicity-induced changes in plasma membrane permeability to myo-inositol Pino [m/s] and expression/localization of SLC5A3. Pino values were determined by cell volumetry over a wide tonicity range (100–275 mOsm) in myo-inositol-substituted solutions. While being negligible under mild hypotonicity (200–275 mOsm), Pino grew rapidly at osmolalities below 200 mOsm to reach a maximum of ∼3 nm/s at 100–125 mOsm, as indicated by fast cell swelling due to myo-inositol influx. The increase in Pino resulted most likely from the hypotonicity-mediated incorporation of cytosolic SLC5A3 into the plasma membrane, as revealed by confocal fluorescence microscopy of cells expressing EGFP-tagged SLC5A3 and super-resolution imaging of immunostained SLC5A3 by direct stochastic optical reconstruction microscopy (dSTORM). dSTORM in hypotonic cells revealed a surface density of membrane-associated SLC5A3 proteins of 200–2000 localizations/μm2. Assuming SLC5A3 to be the major path for myo-inositol, a turnover rate of 80–800 myo-inositol molecules per second for a single transporter protein was estimated from combined volumetric and dSTORM data. Hypotonic stress also caused a significant upregulation of SLC5A3 gene expression as detected by semiquantitative RT-PCR and Western blot analysis. In summary, our data provide first evidence for swelling-mediated activation of SLC5A3 thus suggesting a functional role of this transporter in hypotonic volume regulation of mammalian cells. KW - electrolytes KW - isotonic KW - membrane proteins KW - cell membranes KW - hypotonic KW - hypotonic solutions KW - tonicity KW - permeability Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-126408 VL - 10 IS - 3 ER - TY - JOUR A1 - Ankenbrand, Markus J. A1 - Shainberg, Liliia A1 - Hock, Michael A1 - Lohr, David A1 - Schreiber, Laura M. T1 - Sensitivity analysis for interpretation of machine learning based segmentation models in cardiac MRI JF - BMC Medical Imaging N2 - Background Image segmentation is a common task in medical imaging e.g., for volumetry analysis in cardiac MRI. Artificial neural networks are used to automate this task with performance similar to manual operators. However, this performance is only achieved in the narrow tasks networks are trained on. Performance drops dramatically when data characteristics differ from the training set properties. Moreover, neural networks are commonly considered black boxes, because it is hard to understand how they make decisions and why they fail. Therefore, it is also hard to predict whether they will generalize and work well with new data. Here we present a generic method for segmentation model interpretation. Sensitivity analysis is an approach where model input is modified in a controlled manner and the effect of these modifications on the model output is evaluated. This method yields insights into the sensitivity of the model to these alterations and therefore to the importance of certain features on segmentation performance. Results We present an open-source Python library (misas), that facilitates the use of sensitivity analysis with arbitrary data and models. We show that this method is a suitable approach to answer practical questions regarding use and functionality of segmentation models. We demonstrate this in two case studies on cardiac magnetic resonance imaging. The first case study explores the suitability of a published network for use on a public dataset the network has not been trained on. The second case study demonstrates how sensitivity analysis can be used to evaluate the robustness of a newly trained model. Conclusions Sensitivity analysis is a useful tool for deep learning developers as well as users such as clinicians. It extends their toolbox, enabling and improving interpretability of segmentation models. Enhancing our understanding of neural networks through sensitivity analysis also assists in decision making. Although demonstrated only on cardiac magnetic resonance images this approach and software are much more broadly applicable. KW - deep learning KW - neural networks KW - cardiac magnetic resonance KW - sensitivity analysis KW - transformations KW - augmentation KW - segmentation Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-259169 VL - 21 IS - 1 ER - TY - JOUR A1 - Ankenbrand, Markus J. A1 - Weber, Lorenz A1 - Becker, Dirk A1 - Förster, Frank A1 - Bemm, Felix T1 - TBro: visualization and management of de novo transcriptomes JF - Database N2 - RNA sequencing (RNA-seq) has become a powerful tool to understand molecular mechanisms and/or developmental programs. It provides a fast, reliable and cost-effective method to access sets of expressed elements in a qualitative and quantitative manner. Especially for non-model organisms and in absence of a reference genome, RNA-seq data is used to reconstruct and quantify transcriptomes at the same time. Even SNPs, InDels, and alternative splicing events are predicted directly from the data without having a reference genome at hand. A key challenge, especially for non-computational personnal, is the management of the resulting datasets, consisting of different data types and formats. Here, we present TBro, a flexible de novo transcriptome browser, tackling this challenge. TBro aggregates sequences, their annotation, expression levels as well as differential testing results. It provides an easy-to-use interface to mine the aggregated data and generate publication-ready visualizations. Additionally, it supports users with an intuitive cart system, that helps collecting and analysing biological meaningful sets of transcripts. TBro’s modular architecture allows easy extension of its functionalities in the future. Especially, the integration of new data types such as proteomic quantifications or array-based gene expression data is straightforward. Thus, TBro is a fully featured yet flexible transcriptome browser that supports approaching complex biological questions and enhances collaboration of numerous researchers. KW - database Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-147954 VL - 2016 ER - TY - JOUR A1 - Appel, Mirjam A1 - Scholz, Claus-Jürgen A1 - Müller, Tobias A1 - Dittrich, Marcus A1 - König, Christian A1 - Bockstaller, Marie A1 - Oguz, Tuba A1 - Khalili, Afshin A1 - Antwi-Adjei, Emmanuel A1 - Schauer, Tamas A1 - Margulies, Carla A1 - Tanimoto, Hiromu A1 - Yarali, Ayse T1 - Genome-Wide Association Analyses Point to Candidate Genes for Electric Shock Avoidance in Drosophila melanogaster JF - PLoS ONE N2 - Electric shock is a common stimulus for nociception-research and the most widely used reinforcement in aversive associative learning experiments. Yet, nothing is known about the mechanisms it recruits at the periphery. To help fill this gap, we undertook a genome-wide association analysis using 38 inbred Drosophila melanogaster strains, which avoided shock to varying extents. We identified 514 genes whose expression levels and/or sequences covaried with shock avoidance scores. We independently scrutinized 14 of these genes using mutants, validating the effect of 7 of them on shock avoidance. This emphasizes the value of our candidate gene list as a guide for follow-up research. In addition, by integrating our association results with external protein-protein interaction data we obtained a shock avoidance- associated network of 38 genes. Both this network and the original candidate list contained a substantial number of genes that affect mechanosensory bristles, which are hairlike organs distributed across the fly's body. These results may point to a potential role for mechanosensory bristles in shock sensation. Thus, we not only provide a first list of candidate genes for shock avoidance, but also point to an interesting new hypothesis on nociceptive mechanisms. KW - functional analysis KW - disruption project KW - natural variation KW - complex traits KW - networks KW - behavior KW - flies KW - temperature KW - genetics KW - painful Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-152006 VL - 10 IS - 5 ER - TY - THES A1 - Aschenbrenner, Doris T1 - Human Robot Interaction Concepts for Human Supervisory Control and Telemaintenance Applications in an Industry 4.0 Environment T1 - Mensch-Roboter-Interaktionskonzepte für Fernsteuerungs- und Fernwartungsanwendungen in einer Industrie 4.0 Umgebung N2 - While teleoperation of technical highly sophisticated systems has already been a wide field of research, especially for space and robotics applications, the automation industry has not yet benefited from its results. Besides the established fields of application, also production lines with industrial robots and the surrounding plant components are in need of being remotely accessible. This is especially critical for maintenance or if an unexpected problem cannot be solved by the local specialists. Special machine manufacturers, especially robotics companies, sell their technology worldwide. Some factories, for example in emerging economies, lack qualified personnel for repair and maintenance tasks. When a severe failure occurs, an expert of the manufacturer needs to fly there, which leads to long down times of the machine or even the whole production line. With the development of data networks, a huge part of those travels can be omitted, if appropriate teleoperation equipment is provided. This thesis describes the development of a telemaintenance system, which was established in an active production line for research purposes. The customer production site of Braun in Marktheidenfeld, a factory which belongs to Procter & Gamble, consists of a six-axis cartesian industrial robot by KUKA Industries, a two-component injection molding system and an assembly unit. The plant produces plastic parts for electric toothbrushes. In the research projects "MainTelRob" and "Bayern.digital", during which this plant was utilised, the Zentrum für Telematik e.V. (ZfT) and its project partners develop novel technical approaches and procedures for modern telemaintenance. The term "telemaintenance" hereby refers to the integration of computer science and communication technologies into the maintenance strategy. It is particularly interesting for high-grade capital-intensive goods like industrial robots. Typical telemaintenance tasks are for example the analysis of a robot failure or difficult repair operations. The service department of KUKA Industries is responsible for the worldwide distributed customers who own more than one robot. Currently such tasks are offered via phone support and service staff which travels abroad. They want to expand their service activities on telemaintenance and struggle with the high demands of teleoperation especially regarding security infrastructure. In addition, the facility in Marktheidenfeld has to keep up with the high international standards of Procter & Gamble and wants to minimize machine downtimes. Like 71.6 % of all German companies, P&G sees a huge potential for early information on their production system, but complains about the insufficient quality and the lack of currentness of data. The main research focus of this work lies on the human machine interface for all human tasks in a telemaintenance setup. This thesis provides own work in the use of a mobile device in context of maintenance, describes new tools on asynchronous remote analysis and puts all parts together in an integrated telemaintenance infrastructure. With the help of Augmented Reality, the user performance and satisfaction could be raised. A special regard is put upon the situation awareness of the remote expert realized by different camera viewpoints. In detail the work consists of: - Support of maintenance tasks with a mobile device - Development and evaluation of a context-aware inspection tool - Comparison of a new touch-based mobile robot programming device to the former teach pendant - Study on Augmented Reality support for repair tasks with a mobile device - Condition monitoring for a specific plant with industrial robot - Human computer interaction for remote analysis of a single plant cycle - A big data analysis tool for a multitude of cycles and similar plants - 3D process visualization for a specific plant cycle with additional virtual information - Network architecture in hardware, software and network infrastructure - Mobile device computer supported collaborative work for telemaintenance - Motor exchange telemaintenance example in running production environment - Augmented reality supported remote plant visualization for better situation awareness N2 - Die Fernsteuerung technisch hochentwickelter Systeme ist seit vielen Jahren ein breites Forschungsfeld, vor allem im Bereich von Weltraum- und Robotikanwendungen. Allerdings hat die Automatisierungsindustrie bislang zu wenig von den Ergebnissen dieses Forschungsgebiets profitiert. Auch Fertigungslinien mit Industrierobotern und weiterer Anlagenkomponenten müssen über die Ferne zugänglich sein, besonders bei Wartungsfällen oder wenn unvorhergesehene Probleme nicht von den lokalen Spezialisten gelöst werden können. Hersteller von Sondermaschinen wie Robotikfirmen verkaufen ihre Technologie weltweit. Kunden dieser Firmen besitzen beispielsweise Fabriken in Schwellenländern, wo es an qualifizierten Personal für Reparatur und Wartung mangelt. Wenn ein ernster Fehler auftaucht, muss daher ein Experte des Sondermaschinenherstellers zum Kunden fliegen. Das führt zu langen Stillstandzeiten der Maschine. Durch die Weiterentwicklung der Datennetze könnte ein großer Teil dieser Reisen unterbleiben, wenn eine passende Fernwartungsinfrastruktur vorliegen würde. Diese Arbeit beschreibt die Entwicklung eines Fernwartungssystems, welches in einer aktiven Produktionsumgebung für Forschungszwecke eingerichtet wurde. Die Fertigungsanlage des Kunden wurde von Procter & Gamble in Marktheidenfeld zur Verfügung gestellt und besteht aus einem sechsachsigen, kartesischen Industrieroboter von KUKA Industries, einer Zweikomponentenspritzgussanlage und einer Montageeinheit. Die Anlage produziert Plastikteile für elektrische Zahnbürsten. Diese Anlage wurde im Rahmen der Forschungsprojekte "MainTelRob" und "Bayern.digital" verwendet, in denen das Zentrum für Telematik e.V. (ZfT) und seine Projektpartner neue Ansätze und Prozeduren für moderne Fernwartungs-Technologien entwickeln. Fernwartung bedeutet für uns die umfassende Integration von Informatik und Kommunikationstechnologien in der Wartungsstrategie. Das ist vor allem für hochentwickelte, kapitalintensive Güter wie Industrierobotern interessant. Typische Fernwartungsaufgaben sind beispielsweise die Analyse von Roboterfehlermeldungen oder schwierige Reparaturmaßnahmen. Die Service-Abteilung von KUKA Industries ist für die weltweit verteilten Kunden zuständig, die teilweise auch mehr als einen Roboter besitzen. Aktuell werden derartige Aufgaben per Telefonauskunft oder mobilen Servicekräften, die zum Kunden reisen, erledigt. Will man diese komplizierten Aufgaben durch Fernwartung ersetzen um die Serviceaktivitäten auszuweiten muss man mit den hohen Anforderungen von Fernsteuerung zurechtkommen, besonders in Bezug auf Security Infrastruktur. Eine derartige umfassende Herangehensweise an Fernwartung bietet aber auch einen lokalen Mehrwert beim Kunden: Die Fabrik in Marktheidenfeld muss den hohen internationalen Standards von Procter & Gamble folgen und will daher die Stillstandzeiten weiter verringern. Wie 71,6 Prozent aller deutschen Unternehmen sieht auch P&G Marktheidenfeld ein großes Potential für frühe Informationen aus ihrem Produktionssystem, haben aber aktuell noch Probleme mit der Aktualität und Qualität dieser Daten. Der Hauptfokus der hier vorgestellten Forschung liegt auf der Mensch-Maschine-Schnittstelle für alle Aufgaben eines umfassenden Fernwartungskontextes. Diese Arbeit stellt die eigene Arbeiten bei der Verwendung mobiler Endgeräte im Kontext der Wartung und neue Softwarewerkzeuge für die asynchrone Fernanalyse vor und integriert diese Aspekte in eine Fernwartungsinfrastruktur. In diesem Kontext kann gezeigt werden, dass der Einsatz von Augmented Reality die Nutzerleistung und gleichzeitig die Zufriedenheit steigern kann. Dabei wird auf das sogenannte "situative Bewusstsein" des entfernten Experten besonders Wert gelegt. Im Detail besteht die Arbeit aus: - Unterstützung von Wartungsaufgaben mit mobilen Endgeräten - Entwicklung und Evaluation kontextsensitiver Inspektionssoftware - Vergleich von touch-basierten Roboterprogrammierung mit der Vorgängerversion des Programmierhandgeräts - Studien über die Unterstützung von Reparaturaufgaben durch Augmented Reality - Zustandsüberwachung für eine spezielle Anlage mit Industrieroboter - Mensch-Maschine Interaktion für die Teleanalyse eines Produktionszyklus - Grafische Big Data Analyse einer Vielzahl von Produktionszyklen - 3D Prozess Visualisierung und Anreicherung mit virtuellen Informationen - Hardware, Software und Netzwerkarchitektur für die Fernwartung - Computerunterstützte Zusammenarbeit mit Verwendung mobiler Endgeräte für die Fernwartung - Fernwartungsbeispiel: Durchführung eines Motortauschs in der laufenden Produktion - Augmented Reality unterstütze Visualisierung des Anlagenkontextes für die Steigerung des situativen Bewusstseins T3 - Forschungsberichte in der Robotik = Research Notes in Robotics - 13 KW - Fernwartung KW - Robotik KW - Mensch-Maschine-Schnittstelle KW - Erweiterte Realität KW - Situation Awareness KW - Industrie 4.0 KW - Industrial internet Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-150520 SN - 978-3-945459-18-8 ER - TY - JOUR A1 - Atienza, Nieves A1 - de Castro, Natalia A1 - Cortés, Carmen A1 - Garrido, M. Ángeles A1 - Grima, Clara I. A1 - Hernández, Gregorio A1 - Márquez, Alberto A1 - Moreno-González, Auxiliadora A1 - Nöllenburg, Martin A1 - Portillo, José Ramón A1 - Reyes, Pedro A1 - Valenzuela, Jesús A1 - Trinidad Villar, Maria A1 - Wolff, Alexander T1 - Cover contact graphs N2 - We study problems that arise in the context of covering certain geometric objects called seeds (e.g., points or disks) by a set of other geometric objects called cover (e.g., a set of disks or homothetic triangles). We insist that the interiors of the seeds and the cover elements are pairwise disjoint, respectively, but they can touch. We call the contact graph of a cover a cover contact graph (CCG). We are interested in three types of tasks, both in the general case and in the special case of seeds on a line: (a) deciding whether a given seed set has a connected CCG, (b) deciding whether a given graph has a realization as a CCG on a given seed set, and (c) bounding the sizes of certain classes of CCG’s. Concerning (a) we give efficient algorithms for the case that seeds are points and show that the problem becomes hard if seeds and covers are disks. Concerning (b) we show that this problem is hard even for point seeds and disk covers (given a fixed correspondence between graph vertices and seeds). Concerning (c) we obtain upper and lower bounds on the number of CCG’s for point seeds. KW - Informatik Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-78845 ER - TY - THES A1 - Atzmüller, Martin T1 - Knowledge-Intensive Subgroup Mining - Techniques for Automatic and Interactive Discovery T1 - Wissensintensive Subgruppenentdeckung – Automatische und Interaktive Entdeckungsmethoden N2 - Data mining has proved its significance in various domains and applications. As an important subfield of the general data mining task, subgroup mining can be used, e.g., for marketing purposes in business domains, or for quality profiling and analysis in medical domains. The goal is to efficiently discover novel, potentially useful and ultimately interesting knowledge. However, in real-world situations these requirements often cannot be fulfilled, e.g., if the applied methods do not scale for large data sets, if too many results are presented to the user, or if many of the discovered patterns are already known to the user. This thesis proposes a combination of several techniques in order to cope with the sketched problems: We discuss automatic methods, including heuristic and exhaustive approaches, and especially present the novel SD-Map algorithm for exhaustive subgroup discovery that is fast and effective. For an interactive approach we describe techniques for subgroup introspection and analysis, and we present advanced visualization methods, e.g., the zoomtable that directly shows the most important parameters of a subgroup and that can be used for optimization and exploration. We also describe various visualizations for subgroup comparison and evaluation in order to support the user during these essential steps. Furthermore, we propose to include possibly available background knowledge that is easy to formalize into the mining process. We can utilize the knowledge in many ways: To focus the search process, to restrict the search space, and ultimately to increase the efficiency of the discovery method. We especially present background knowledge to be applied for filtering the elements of the problem domain, for constructing abstractions, for aggregating values of attributes, and for the post-processing of the discovered set of patterns. Finally, the techniques are combined into a knowledge-intensive process supporting both automatic and interactive methods for subgroup mining. The practical significance of the proposed approach strongly depends on the available tools. We introduce the VIKAMINE system as a highly-integrated environment for knowledge-intensive active subgroup mining. Also, we present an evaluation consisting of two parts: With respect to objective evaluation criteria, i.e., comparing the efficiency and the effectiveness of the subgroup discovery methods, we provide an experimental evaluation using generated data. For that task we present a novel data generator that allows a simple and intuitive specification of the data characteristics. The results of the experimental evaluation indicate that the novel SD-Map method outperforms the other described algorithms using data sets similar to the intended application concerning the efficiency, and also with respect to precision and recall for the heuristic methods. Subjective evaluation criteria include the user acceptance, the benefit of the approach, and the interestingness of the results. We present five case studies utilizing the presented techniques: The approach has been successfully implemented in medical and technical applications using real-world data sets. The method was very well accepted by the users that were able to discover novel, useful, and interesting knowledge. N2 - Data Mining wird mit großem Erfolg in vielen Domänen angewandt. Subgruppenentdeckung als wichtiges Teilgebiet des Data Mining kann zum Beispiel gut im Marketing, oder zur Qualitätskontrolle und Analyse in medizinischen Domänen eingesetzt werden. Das allgemeine Ziel besteht darin, potentiell nützliches and letztendlich interessantes Wissen zu entdecken. Jedoch können diese Anforderungen im praktischen Einsatz oft nicht erfüllt werden, etwa falls die eingesetzten Methoden eine schlechte Skalierbarkeit für größere Datensätze aufweisen, falls dem Benutzer zu viele Ergebnisse präsentiert werden, oder falls der Anwender viele der gefundenen Subgruppen-Muster schon kennt. Diese Arbeit stellt eine Kombination von automatischen und interaktiven Techniken vor, um mit den genannten Problemen besser umgehen zu können: Es werden automatische heuristische und vollständige Subgruppenentdeckungs-Verfahren diskutiert, und insbesondere der neuartige SD-Map Algorithmus zur vollständigen Subgruppenentdeckung vorgestellt der sowohl schnell als auch effektiv ist. Bezüglich der interaktiven Techniken werden Methoden zur Subgruppen-Introspektion und Analyse, und fortgeschrittene Visualisierungstechniken vorgestellt, beispielsweise die Zoomtable, die die für die Subgruppenentdeckung wichtigsten Parameter direkt visualisiert und zur Optimierung und Exploration eingesetzt werden kann. Zusätzlich werden verschiedene Visualisierungen zum Vergleich und zur Evaluation von Subgruppen beschrieben um den Benutzer bei diesen essentiellen Schritten zu unterstützen. Weiterhin wird leicht zu formalisierendes Hintergrundwissen vorgestellt, das im Subgruppenentdeckungsprozess in vielfältiger Weise eingesetzt werden kann: Um den Entdeckungsprozess zu fokussieren, den Suchraum einzuschränken, und letztendlich die Effizienz der Entdeckungsmethode zu erhöhen. Insbesondere wird Hintergrundwissen eingeführt, um die Elemente der Anwendungsdomäne zu filtern, um geeignete Abstraktionen zu definieren, Werte zusammenzufassen, und die gefundenen Subgruppenmuster nachzubearbeiten. Schließlich werden diese Techniken in einen wissensintensiven Prozess integriert, der sowohl automatische als auch interaktive Methoden zur Subgruppenentdeckung einschließt. Die praktische Bedeutung des vorgestellten Ansatzes hängt stark von den verfügbaren Werkzeugen ab. Dazu wird das VIKAMINE System als hochintegrierte Umgebung für die wissensintensive aktive Subgruppenentdeckung präsentiert. Die Evaluation des Ansatzes besteht aus zwei Teilen: Hinsichtlich einer Evaluation von Effizienz und Effektivität der Verfahren wird eine experimentelle Evaluation mit synthetischen Daten vorgestellt. Für diesen Zweck wird ein neuartiger in der Arbeit entwickelter Datengenerator angewandt, der eine einfache und intuitive Spezifikation der Datencharakteristiken erlaubt. Für die Evaluation des Ansatzes wurden Daten erzeugt, die ähnliche Charakteristiken aufweisen wie die Daten des angestrebten Einsatzbereichs. Die Ergebnisse der Evaluation zeigen, dass der neuartige SD-Map Algorithmus den anderen in der Arbeit beschriebenen Standard-Algorithmen überlegen ist. Sowohl hinsichtlich der Effizienz, als auch von Precision/Recall bezogen auf die heuristischen Algorithmen bietet SD-Map deutliche Vorteile. Subjektive Evaluationskriterien sind durch die Benutzerakzeptanz, den Nutzen des Ansatzes, und die Interessantheit der Ergebnisse gegeben. Es werden fünf Fallstudien für den Einsatz der vorgestellten Techniken beschrieben: Der Ansatz wurde in medizinischen und technischen Anwendungen mit realen Daten eingesetzt. Dabei wurde er von den Benutzern sehr gut angenommen, und im praktischen Einsatz konnte neuartiges, nützliches, und interessantes Wissen entdeckt werden. KW - Data Mining KW - Algorithmus KW - Visualisierung KW - Subgruppenentdeckung KW - Hintergrundwissen KW - Wissensendeckung KW - Data Mining KW - Visualisierung KW - Subgroup Mining KW - Background Knowledge KW - Knowledge Discovery KW - Data Mining KW - Visualization Y1 - 2006 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-21004 ER - TY - THES A1 - Baier, Herbert T1 - Operators of Higher Order N2 - Motivated by results on interactive proof systems we investigate the computational power of quantifiers applied to well-known complexity classes. In special, we are interested in existential, universal and probabilistic bounded error quantifiers ranging over words and sets of words, i.e. oracles if we think in a Turing machine model. In addition to the standard oracle access mechanism, we also consider quantifiers ranging over oracles to which access is restricted in a certain way. N2 - Angeregt durch die Resultate über interaktive Beweissysteme untersuchen wir Quantoren in Anwendung auf bereits bekannte Komplexitätsklassen hinsichtlich ihrer dadurch gegebenen Berechnungsmächtigkeit. Von besonderem Interesse sind dabei existentielle und universelle Quantoren sowie Quantoren mit begrenzter Fehlerwahrscheinlichkeit, die alle über Wörter oder Wortmengen (Orakel im Kontext der Turingmaschinen) quantifizieren. Außer in Bezug auf den Standardmechanismus eines Orakelzugriffs werden auch Quantifizierungen über Orakel, für deren Zugriff gewisse Beschränkungen bestehen, betrachtet. KW - Komplexitätstheorie KW - Quantor KW - Operator KW - Komplexitätsklasse Y1 - 1998 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-140799 SN - 3-8265-4008-5 PB - Shaker Verlag ER - TY - THES A1 - Baier, Pablo A. T1 - Simulator for Minimally Invasive Vascular Interventions: Hardware and Software T1 - VR-Simulation für das Training von Herzkathetereingriffen: Hard- und Softwarelösung N2 - A complete simulation system is proposed that can be used as an educational tool by physicians in training basic skills of Minimally Invasive Vascular Interventions. In the first part, a surface model is developed to assemble arteries having a planar segmentation. It is based on Sweep Surfaces and can be extended to T- and Y-like bifurcations. A continuous force vector field is described, representing the interaction between the catheter and the surface. The computation time of the force field is almost unaffected when the resolution of the artery is increased. The mechanical properties of arteries play an essential role in the study of the circulatory system dynamics, which has been becoming increasingly important in the treatment of cardiovascular diseases. In Virtual Reality Simulators, it is crucial to have a tissue model that responds in real time. In this work, the arteries are discretized by a two dimensional mesh and the nodes are connected by three kinds of linear springs. Three tissue layers (Intima, Media, Adventitia) are considered and, starting from the stretch-energy density, some of the elasticity tensor components are calculated. The physical model linearizes and homogenizes the material response, but it still contemplates the geometric nonlinearity. In general, if the arterial stretch varies by 1% or less, then the agreement between the linear and nonlinear models is trustworthy. In the last part, the physical model of the wire proposed by Konings is improved. As a result, a simpler and more stable method is obtained to calculate the equilibrium configuration of the wire. In addition, a geometrical method is developed to perform relaxations. It is particularly useful when the wire is hindered in the physical method because of the boundary conditions. The physical and the geometrical methods are merged, resulting in efficient relaxations. Tests show that the shape of the virtual wire agrees with the experiment. The proposed algorithm allows real-time executions and the hardware to assemble the simulator has a low cost. N2 - Es wird ein vollständiges Simulationssystem entwickelt, das von Ärzten als Lehrmittel zur Ausbildung grundlegender Fertigkeiten bei Herzkathetereingriffen eingesetzt werden kann. Im ersten Teil wird ein Oberflächenmodell zur Erstellung von Arterien mit planarer Segmentierung entwickelt. Im zweiten Teil werden die Arterien durch ein zweidimensionales Netz diskretisiert, die Knoten werden durch drei Arten linearer Federn verbunden und ausgehend von einer Dehnungsenergie-Dichte-Funktion werden einige Komponenten des Elastizitätstensors berechnet. Im letzten Teil wird das von anderen Autoren vorgeschlagene physikalische Modell des Drahtes verbessert und eine neue geometrische Methode entwickelt. Der vorgeschlagene Algorithmus ermöglicht Echtzeit-Ausführungen. Die Hardware des Simulators hat geringe Herstellungskosten. T3 - Forschungsberichte in der Robotik = Research Notes in Robotics - 15 KW - Computersimulation KW - Simulator KW - Arterie KW - Elastizitätstensor KW - Herzkatheter KW - Minimally invasive vascular intervention KW - Wire relaxation KW - Artery KW - Elasticity tensor KW - Stiffness KW - educational tool KW - Elastizitätstensor KW - Herzkathetereingriff KW - Software KW - Hardware Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-161190 SN - 978-3-945459-22-5 ER - TY - JOUR A1 - Baier, Pablo A. A1 - Baier-Saip, Jürgen A. A1 - Schilling, Klaus A1 - Oliveira, Jauvane C. T1 - Simulator for Minimally Invasive Vascular Interventions: Hardware and Software JF - Presence N2 - In the present work, a simulation system is proposed that can be used as an educational tool by physicians in training basic skills of minimally invasive vascular interventions. In order to accomplish this objective, initially the physical model of the wire proposed by Konings has been improved. As a result, a simpler and more stable method was obtained to calculate the equilibrium configuration of the wire. In addition, a geometrical method is developed to perform relaxations. It is particularly useful when the wire is hindered in the physical method because of the boundary conditions. Then a recipe is given to merge the physical and the geometrical methods, resulting in efficient relaxations. Moreover, tests have shown that the shape of the virtual wire agrees with the experiment. The proposed algorithm allows real-time executions, and furthermore, the hardware to assemble the simulator has a low cost. KW - simulation system KW - educational tool KW - invasive vascular interventions Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-140580 SN - 1531-3263 VL - 25 IS - 2 ER - TY - JOUR A1 - Bartl, Andrea A1 - Wenninger, Stephan A1 - Wolf, Erik A1 - Botsch, Mario A1 - Latoschik, Marc Erich T1 - Affordable but not cheap: a case study of the effects of two 3D-reconstruction methods of virtual humans JF - Frontiers in Virtual Reality N2 - Realistic and lifelike 3D-reconstruction of virtual humans has various exciting and important use cases. Our and others’ appearances have notable effects on ourselves and our interaction partners in virtual environments, e.g., on acceptance, preference, trust, believability, behavior (the Proteus effect), and more. Today, multiple approaches for the 3D-reconstruction of virtual humans exist. They significantly vary in terms of the degree of achievable realism, the technical complexities, and finally, the overall reconstruction costs involved. This article compares two 3D-reconstruction approaches with very different hardware requirements. The high-cost solution uses a typical complex and elaborated camera rig consisting of 94 digital single-lens reflex (DSLR) cameras. The recently developed low-cost solution uses a smartphone camera to create videos that capture multiple views of a person. Both methods use photogrammetric reconstruction and template fitting with the same template model and differ in their adaptation to the method-specific input material. Each method generates high-quality virtual humans ready to be processed, animated, and rendered by standard XR simulation and game engines such as Unreal or Unity. We compare the results of the two 3D-reconstruction methods in an immersive virtual environment against each other in a user study. Our results indicate that the virtual humans from the low-cost approach are perceived similarly to those from the high-cost approach regarding the perceived similarity to the original, human-likeness, beauty, and uncanniness, despite significant differences in the objectively measured quality. The perceived feeling of change of the own body was higher for the low-cost virtual humans. Quality differences were perceived more strongly for one’s own body than for other virtual humans. KW - virtual humans KW - 3D-reconstruction methods KW - avatars KW - agents KW - user study Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-260492 VL - 2 ER - TY - THES A1 - Baunach, Marcel T1 - Advances in Distributed Real-Time Sensor/Actuator Systems Operation - Operating Systems, Communication, and Application Design Concepts - T1 - Fortschritte im Betrieb drahtloser Sensor/Aktuator Netzwerke N2 - This work takes a close look at several quite different research areas related to the design of networked embedded sensor/actuator systems. The variety of the topics illustrates the potential complexity of current sensor network applications; especially when enriched with actuators for proactivity and environmental interaction. Besides their conception, development, installation and long-term operation, we'll mainly focus on more "low-level" aspects: Compositional hardware and software design, task cooperation and collaboration, memory management, and real-time operation will be addressed from a local node perspective. In contrast, inter-node synchronization, communication, as well as sensor data acquisition, aggregation, and fusion will be discussed from a rather global network view. The diversity in the concepts was intentionally accepted to finally facilitate the reliable implementation of truly complex systems. In particular, these should go beyond the usual "sense and transmit of sensor data", but show how powerful today's networked sensor/actuator systems can be despite of their low computational performance and constrained hardware: If their resources are only coordinated efficiently! N2 - Diese Arbeit behandelt einige sehr unterschiedliche Forschungsbereiche bezüglich des Designs vernetzter und eingebetteter Sensor/Aktuator-Systeme. Die Vielfalt der Themen zeigt die potenzielle Komplexität aktueller Sensornetzwerk-Anwendungen, insbesondere wenn sie mit Aktuatoren zur Interaktion mit der Umwelt ausgestattet sind. Neben deren Konzeption, Entwicklung, Installation und dem langfristigen Betrieb wird besonders auf diverse "low-level" Aspekte eingegangen: Kompositionelles Hardware- und Software-Design, Task Kooperation und Kollaboration, Speicher-Verwaltung und Echtzeit-Betrieb werden aus lokaler Sicht der Sensorknoten betrachtet. Im Kontrast werden Knoten-Synchronisation, Kommunikation, sowie Sensordatenerfassung, -aggregation und -fusion aus globaler Netzwerk-Sicht diskutiert. Die Vielfalt der behandelten Konzepte wurde bewusst in Kauf genommen, um letztlich die zuverlässige Umsetzung sehr komplexer Systeme zu erleichtern. Insbesondere sollte dies über das übliche "Erfassen und Übertragen von Sensordaten" hinausgehen, und zeigen, wie mächtig heutige vernetzte Sensor/Aktuator-Systeme trotz ihrer geringen Rechenleistung und eingeschränkten Hardware sein können: Wenn ihre Ressourcen effizient koordiniert werden! KW - Eingebettetes System KW - Drahtloses Sensorsystem KW - Echtzeitsystem KW - Dynamische Speicherverwaltung KW - Ressourcenallokation KW - Fernwartung KW - Betriebssystem KW - Verteiltes System KW - Lokalisation KW - Embedded Systems KW - Real-Time Operating Systems KW - Localization KW - Wireless Sensor/Actuator Systems KW - Dynamic Memory Management Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-76489 ER - TY - JOUR A1 - Becker, Martin A1 - Caminiti, Saverio A1 - Fiorella, Donato A1 - Francis, Louise A1 - Gravino, Pietro A1 - Haklay, Mordechai (Muki) A1 - Hotho, Andreas A1 - Loreto, Virrorio A1 - Mueller, Juergen A1 - Ricchiuti, Ferdinando A1 - Servedio, Vito D. P. A1 - Sirbu, Alina A1 - Tria, Franesca T1 - Awareness and Learning in Participatory Noise Sensing JF - PLOS ONE N2 - The development of ICT infrastructures has facilitated the emergence of new paradigms for looking at society and the environment over the last few years. Participatory environmental sensing, i.e. directly involving citizens in environmental monitoring, is one example, which is hoped to encourage learning and enhance awareness of environmental issues. In this paper, an analysis of the behaviour of individuals involved in noise sensing is presented. Citizens have been involved in noise measuring activities through the WideNoise smartphone application. This application has been designed to record both objective (noise samples) and subjective (opinions, feelings) data. The application has been open to be used freely by anyone and has been widely employed worldwide. In addition, several test cases have been organised in European countries. Based on the information submitted by users, an analysis of emerging awareness and learning is performed. The data show that changes in the way the environment is perceived after repeated usage of the application do appear. Specifically, users learn how to recognise different noise levels they are exposed to. Additionally, the subjective data collected indicate an increased user involvement in time and a categorisation effect between pleasant and less pleasant environments. KW - exposure Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-127675 SN - 1932-6203 VL - 8 IS - 12 ER - TY - JOUR A1 - Bencurova, Elena A1 - Shityakov, Sergey A1 - Schaack, Dominik A1 - Kaltdorf, Martin A1 - Sarukhanyan, Edita A1 - Hilgarth, Alexander A1 - Rath, Christin A1 - Montenegro, Sergio A1 - Roth, Günter A1 - Lopez, Daniel A1 - Dandekar, Thomas T1 - Nanocellulose composites as smart devices with chassis, light-directed DNA Storage, engineered electronic properties, and chip integration JF - Frontiers in Bioengineering and Biotechnology N2 - The rapid development of green and sustainable materials opens up new possibilities in the field of applied research. Such materials include nanocellulose composites that can integrate many components into composites and provide a good chassis for smart devices. In our study, we evaluate four approaches for turning a nanocellulose composite into an information storage or processing device: 1) nanocellulose can be a suitable carrier material and protect information stored in DNA. 2) Nucleotide-processing enzymes (polymerase and exonuclease) can be controlled by light after fusing them with light-gating domains; nucleotide substrate specificity can be changed by mutation or pH change (read-in and read-out of the information). 3) Semiconductors and electronic capabilities can be achieved: we show that nanocellulose is rendered electronic by iodine treatment replacing silicon including microstructures. Nanocellulose semiconductor properties are measured, and the resulting potential including single-electron transistors (SET) and their properties are modeled. Electric current can also be transported by DNA through G-quadruplex DNA molecules; these as well as classical silicon semiconductors can easily be integrated into the nanocellulose composite. 4) To elaborate upon miniaturization and integration for a smart nanocellulose chip device, we demonstrate pH-sensitive dyes in nanocellulose, nanopore creation, and kinase micropatterning on bacterial membranes as well as digital PCR micro-wells. Future application potential includes nano-3D printing and fast molecular processors (e.g., SETs) integrated with DNA storage and conventional electronics. This would also lead to environment-friendly nanocellulose chips for information processing as well as smart nanocellulose composites for biomedical applications and nano-factories. KW - nanocellulose KW - DNA storage KW - light-gated proteins KW - single-electron transistors KW - protein chip Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-283033 SN - 2296-4185 VL - 10 ER - TY - THES A1 - Betz, Christian T1 - Scalable authoring of diagnostic case based training systems T1 - Skalierbare Erstellung diagnostischer fallbasierter Trainingssysteme N2 - Diagnostic Case Based Training Systems (D-CBT) provide learners with a means to learn and exercise knowledge in a realistic context. In medical education, D-CBT Systems present virtual patients to the learners who are asked to examine, diagnose and state therapies for these patients. Due a number of conflicting and changing requirements, e.g. time for learning, authoring effort, several systems were developed so far. These systems range from simple, easy-to-use presentation systems to highly complex knowledge based systems supporting explorative learning. This thesis presents an approach and tools to create D-CBT systems from existing sources (documents, e.g. dismissal records) using existing tools (word processors): Authors annotate and extend the documents to model the knowledge. A scalable knowledge representation is able to capture the content on multiple levels, from simple to highly structured knowledge. Thus, authoring of D-CBT systems requires less prerequisites and pre-knowledge and is faster than approaches using specialized authoring environments. Also, authors can iteratively add and structure more knowledge to adapt training cases to their learners needs. The theses also discusses the application of the same approach to other domains, especially to knowledge acquisition for the Semantic Web. N2 - Fallbasierte diagnostische Trainingssysteme (FDT) ermöglichen es Lernern, Wissen durch Anwendung in einem realistischen Kontext zu erwerben und zu festigen. In der medizinischen Ausbildung präsentieren FDT Systeme virtuelle Patienten, an denen der Lerner die Auswahl und Interpretation der richtigen Untersuchungen, die Diagnostik und die Bestimmung geeigneter Therapien erlernen und üben kann. Eine Vielzahl von Anforderungen durch die Lerner und die Autoren solcher Systeme hat zur Entwicklung unterschiedlicher Trainingsumgebungen geführt. Darunter gibt es einfache, präsentationsorientierte Systeme ebenso wie komplexe wissensbasierte Systeme, die exploratives Lernern erlauben. Diese Dissertation untersucht einen Ansatz und Werkzeuge, um FDT Systeme aus vorhandenen Daten (d.h. Dokumenten, beispielsweise Entlassschreiben) und mit Hilfe bekannter Werkzeuge (d.h. Textverarbeitung) zu entwickeln: Die Autoren annotieren dazu die Dokumente, um die Fälle zu modellieren. Eine skalierbare Wissensrepräsentation kann das so extrahierte Wissen auf verschiedenen Ebenen erfassen, angefangen mit unstrukturierten Elementen bis zu Wissensmodellen mit kausalen Beziehungen. Autoren können mit Hilfe des vorgestellten Ansatzes fallbasierte diagnostische Trainingssysteme mit geringerem Vorwissen und schneller erstellen als mit Hilfe spezialisierter Autorensysteme. Dabei können die Autoren insbesondere die Fälle sukzessive mit weiterem Wissen anreichern und so auf die Anforderungen ihrer Lerner anpassen. In der Dissertation wird darüber hinaus die Anwendung des Ansatzes und der entstandenen Werkzeuge auf andere Domänen untersucht. Besonders interessant ist dabei die Anwendung in der Wissensakquisition für das Semantic Web. KW - Computerunterstütztes Lernen KW - Medizin KW - Wissensrepräsentation KW - Trainingssystem KW - agile Prozesse KW - Semantic Web KW - d3web.Train KW - knowledge representation KW - training systems KW - agile processes KW - semantic web KW - d3web.Train Y1 - 2005 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-17885 ER - TY - THES A1 - Binder, Andreas T1 - Die stochastische Wissenschaft und zwei Teilsysteme eines Web-basierten Informations- und Anwendungssystems zu ihrer Etablierung T1 - The stochastic science and two subsystems of a web-based information and application system for its establishment N2 - Das stochastische Denken, die Bernoullische Stochastik und dessen informationstechnologische Umsetzung, namens Stochastikon stellen die Grundlage für das Verständnis und die erfolgreiche Nutzung einer stochastischen Wissenschaft dar. Im Rahmen dieser Arbeit erfolgt eine Klärung des Begriffs des stochastischen Denkens, eine anschauliche Darstellung der von Elart von Collani entwickelten Bernoullischen Stochastik und eine Beschreibung von Stochastikon. Dabei werden sowohl das Gesamtkonzept von Stochastikon, sowie die Ziele, Aufgaben und die Realisierung der beiden Teilsysteme namens Mentor und Encyclopedia vorgestellt. Das stochastische Denken erlaubt eine realitätsnahe Sichtweise der Dinge, d.h. eine Sichtweise, die mit den menschlichen Beobachtungen und Erfahrungen im Einklang steht und somit die Unsicherheit über zukünftige Entwicklungen berücksichtigt. Der in diesem Kontext verwendete Begriff der Unsicherheit bezieht sich ausschließlich auf zukünftige Entwicklungen und äußert sich in Variabilität. Quellen der Unsicherheit sind einerseits die menschliche Ignoranz und andererseits der Zufall. Unter Ignoranz wird hierbei die Unwissenheit des Menschen über die unbekannten, aber feststehenden Fakten verstanden, die die Anfangsbedingungen der zukünftigen Entwicklung repräsentieren. Die Bernoullische Stochastik liefert ein Regelwerk und ermöglicht die Entwicklung eines quantitativen Modells zur Beschreibung der Unsicherheit und expliziter Einbeziehung der beiden Quellen Ignoranz und Zufall. Das Modell trägt den Namen Bernoulli-Raum und bildet die Grundlage für die Herleitung quantitativer Verfahren, um zuverlässige und genaue Aussagen sowohl über die nicht-existente zufällige Zukunft (Vorhersageverfahren), als auch über die unbekannte feststehende Vergangenheit (Messverfahren). Das Softwaresystem Stochastikon implementiert die Bernoullische Stochastik in Form einer Reihe autarker, miteinander kommunizierender Teilsysteme. Ziel des Teilsystems Encyclopedia ist die Bereitstellung und Bewertung stochastischen Wissens. Das Teilsystem Mentor dient der Unterstützung des Anwenders bei der Problemlösungsfindung durch Identifikation eines richtigen Modells bzw. eines korrekten Bernoulli-Raums. Der Lösungsfindungsprozess selber enthält keinerlei Unsicherheit. Die ganze Unsicherheit steckt in der Lösung, d.h. im Bernoulli-Raum, der explizit die vorhandene Unwissenheit (Ignoranz) und den vorliegenden Zufall abdeckend enthält. N2 - Stochastic thinking, Bernoulli stochastics and its information technological realization, called Stochastikon, represent the basis for understanding and successfully utilizing stochastic science. This thesis defines the concept of stochastic thinking, introduces Bernoulli stochastics, which has been developed by Elart von Collani, and describes the IT system Stochastikon. The concept and the design of Stochastikon are outlined and the aims, tasks and realizations of the two subsystems Mentor and Encyclopedia are given in detail. Stochastic thinking enables a realistic view of reality. This means a view, which is in agreement with observation and experience and, thus, takes into account uncertainty about future developments. In this context the term of uncertainty is used exclusively with respect to future development and materializes in variability. Sources of uncertainty are on the one hand human ignorance about fixed facts on the one hand and randomness on the other. Bernoulli stochastics makes available a set of rules for developing a quantitative model about uncertainty taking particularly into account the two sources ignorance and randomness. The model is called Bernoulli-Space, which is the basis for reliable and precise quantitative procedures for statements about the random future (prediction procedures) as well as about the unknown fixed past (measurement procedures). The software system, called Stochastikon, implements Bernoulli stochastics based on a set of self-sustained intercommunicating subsystems. The Subsystem Encyclopedia makes stochastical knowledge available, while the Subsystem Mentor supports the user for solving (stochastic) problems by identifying the correct model respectively correct Bernoulli-Space. The problem solving process is free of uncertainty, because all uncertainty is modelled by Bernoulli-space. KW - Stochastik KW - stochastisches Denken KW - Bernoullische Stochastik KW - Bernoulli-Raum KW - Stochastikon KW - stochastic thinking KW - Bernoulli stochastics KW - Bernoullispace KW - Stochastikon Y1 - 2006 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-26146 ER - TY - THES A1 - Binzenhöfer, Andreas T1 - Performance Analysis of Structured Overlay Networks T1 - Leistungsbewertung Strukturierter Overlay Netze N2 - Overlay networks establish logical connections between users on top of the physical network. While randomly connected overlay networks provide only a best effort service, a new generation of structured overlay systems based on Distributed Hash Tables (DHTs) was proposed by the research community. However, there is still a lack of understanding the performance of such DHTs. Additionally, those architectures are highly distributed and therefore appear as a black box to the operator. Yet an operator does not want to lose control over his system and needs to be able to continuously observe and examine its current state at runtime. This work addresses both problems and shows how the solutions can be combined into a more self-organizing overlay concept. At first, we evaluate the performance of structured overlay networks under different aspects and thereby illuminate in how far such architectures are able to support carrier-grade applications. Secondly, to enable operators to monitor and understand their deployed system in more detail, we introduce both active as well as passive methods to gather information about the current state of the overlay network. N2 - Unter einem Overlay Netz versteht man den Zusammenschluss mehrerer Komponenten zu einer logischen Topologie, die auf einer existierenden physikalischen Infrastruktur aufsetzt. Da zufällige Verbindungen zwischen den einzelnen Teilnehmern aber sehr ineffizient sind, wurden strukturierte Overlay Netze entworfen, bei denen die Beziehungen zwischen den einzelnen Teilnehmern fest vorgeschrieben sind. Solche strukturierten Mechanismen versprechen zwar ein großes Potential, dieses wurde aber noch nicht ausreichend untersucht bzw. wissenschaftlich nachgewiesen. In dieser Arbeit wird mit mathematischen Methoden und ereignisorientierter Simulation die Leistungsfähigkeit von strukturierten Overlay Netzen untersucht. Da diese stark von der aktuellen Situation im Overlay abhängt, entwickeln wir Methoden, mit denen sich sowohl passiv, als auch aktiv, wichtige Systemparameter zur Laufzeit abschätzen bzw. messen lassen. Zusammen führen die vorgeschlagenen Methoden zu selbstorganisierenden Mechanismen, die den aktuellen Zustand des Overlays überwachen, diesen bewerten und sich gegebenenfalls automatisch an die aktuellen Verhältnisse anpassen T3 - Würzburger Beiträge zur Leistungsbewertung Verteilter Systeme - 01/08 KW - Overlay-Netz KW - Leistungsbewertung KW - Peer-to-Peer-Netz KW - Mathematisches Modell KW - Chord KW - Kademlia KW - DHT KW - Overlay KW - Chord KW - Kademlia KW - DHT Y1 - 2007 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-26291 ER - TY - THES A1 - Bleier, Michael T1 - Underwater Laser Scanning - Refractive Calibration, Self-calibration and Mapping for 3D Reconstruction T1 - Laserscanning unter Wasser - Refraktive Kalibrierung, Selbstkalibrierung und Kartierung zur 3D Rekonstruktion N2 - There is great interest in affordable, precise and reliable metrology underwater: Archaeologists want to document artifacts in situ with high detail. In marine research, biologists require the tools to monitor coral growth and geologists need recordings to model sediment transport. Furthermore, for offshore construction projects, maintenance and inspection millimeter-accurate measurements of defects and offshore structures are essential. While the process of digitizing individual objects and complete sites on land is well understood and standard methods, such as Structure from Motion or terrestrial laser scanning, are regularly applied, precise underwater surveying with high resolution is still a complex and difficult task. Applying optical scanning techniques in water is challenging due to reduced visibility caused by turbidity and light absorption. However, optical underwater scanners provide significant advantages in terms of achievable resolution and accuracy compared to acoustic systems. This thesis proposes an underwater laser scanning system and the algorithms for creating dense and accurate 3D scans in water. It is based on laser triangulation and the main optical components are an underwater camera and a cross-line laser projector. The prototype is configured with a motorized yaw axis for capturing scans from a tripod. Alternatively, it is mounted to a moving platform for mobile mapping. The main focus lies on the refractive calibration of the underwater camera and laser projector, the image processing and 3D reconstruction. For highest accuracy, the refraction at the individual media interfaces must be taken into account. This is addressed by an optimization-based calibration framework using a physical-geometric camera model derived from an analytical formulation of a ray-tracing projection model. In addition to scanning underwater structures, this work presents the 3D acquisition of semi-submerged structures and the correction of refraction effects. As in-situ calibration in water is complex and time-consuming, the challenge of transferring an in-air scanner calibration to water without re-calibration is investigated, as well as self-calibration techniques for structured light. The system was successfully deployed in various configurations for both static scanning and mobile mapping. An evaluation of the calibration and 3D reconstruction using reference objects and a comparison of free-form surfaces in clear water demonstrate the high accuracy potential in the range of one millimeter to less than one centimeter, depending on the measurement distance. Mobile underwater mapping and motion compensation based on visual-inertial odometry is demonstrated using a new optical underwater scanner based on fringe projection. Continuous registration of individual scans allows the acquisition of 3D models from an underwater vehicle. RGB images captured in parallel are used to create 3D point clouds of underwater scenes in full color. 3D maps are useful to the operator during the remote control of underwater vehicles and provide the building blocks to enable offshore inspection and surveying tasks. The advancing automation of the measurement technology will allow non-experts to use it, significantly reduce acquisition time and increase accuracy, making underwater metrology more cost-effective. N2 - Das Interesse an präziser, zuverlässiger und zugleich kostengünstiger Unterwassermesstechnik ist groß. Beispielsweise wollen Archäologen Artefakte in situ mit hoher Detailtreue dokumentieren und in der Meeresforschung benötigen Biologen Messwerkzeuge zur Beobachtung des Korallenwachstums. Auch Geologen sind auf Messdaten angewiesen, um Sedimenttransporte zu modellieren. Darüber hinaus ist für die Errichtung von Offshore-Bauwerken, sowie deren Wartung und Inspektion eine millimetergenaue Vermessung von vorhandenen Strukturen und Defekten unerlässlich. Während die Digitalisierung einzelner Objekte und ganzer Areale an Land gut erforscht ist und verschiedene Standardmethoden, wie zum Beispiel Structure from Motion oder terrestrisches Laserscanning, regelmäßig eingesetzt werden, ist die präzise und hochauflösende Unterwasservermessung nach wie vor eine komplexe und schwierige Aufgabe. Die Anwendung optischer Messtechnik im Wasser ist aufgrund der eingeschränkten Sichttiefe durch Trübung und Lichtabsorption eine Herausforderung. Optische Unterwasserscanner bieten jedoch Vorteile hinsichtlich der erreichbaren Auflösung und Genauigkeit gegenüber akustischen Systemen. In dieser Arbeit werden ein Unterwasser-Laserscanning-System und die Algorithmen zur Erzeugung von 3D-Scans mit hoher Punktdichte im Wasser vorgestellt. Es basiert auf Lasertriangulation und die optischen Hauptkomponenten sind eine Unterwasserkamera und ein Kreuzlinienlaserprojektor. Das System ist mit einer motorisierten Drehachse ausgestattet, um Scans von einem Stativ aus aufzunehmen. Alternativ kann es von einer beweglichen Plattform aus für mobile Kartierung eingesetzt werden. Das Hauptaugenmerk liegt auf der refraktiven Kalibrierung der Unterwasserkamera und des Laserprojektors, der Bildverarbeitung und der 3D-Rekonstruktion. Um höchste Genauigkeit zu erreichen, muss die Brechung an den einzelnen Medienübergängen berücksichtigt werden. Dies wird durch ein physikalisch-geometrisches Kameramodell, das auf einer analytischen Beschreibung der Strahlenverfolgung basiert, und ein optimierungsbasiertes Kalibrierverfahren erreicht. Neben dem Scannen von Unterwasserstrukturen wird in dieser Arbeit auch die 3D-Erfassung von teilweise im Wasser befindlichen Strukturen und die Korrektur der dabei auftretenden Brechungseffekte vorgestellt. Da die Kalibrierung im Wasser komplex und zeitintensiv ist, wird die Übertragung einer Kalibrierung des Scanners in Luft auf die Bedingungen im Wasser ohne Neukalibrierung, sowie die Selbstkalibrierung für Lichtschnittverfahren untersucht. Das System wurde in verschiedenen Konfigurationen sowohl für statisches Scannen als auch für die mobile Kartierung erfolgreich eingesetzt. Die Validierung der Kalibrierung und der 3D-Rekonstruktion anhand von Referenzobjekten und der Vergleich von Freiformflächen in klarem Wasser zeigen das hohe Genauigkeitspotenzial im Bereich von einem Millimeter bis weniger als einem Zentimeter in Abhängigkeit von der Messdistanz. Die mobile Unterwasserkartierung und Bewegungskompensation anhand visuell-inertialer Odometrie wird mit einem neuen optischen Unterwasserscanner auf Basis der Streifenprojektion demonstriert. Dabei ermöglicht die kontinuierliche Registrierung von Einzelscans die Erfassung von 3D-Modellen von einem Unterwasserfahrzeug aus. Mit Hilfe von parallel aufgenommenen RGB-Bildern werden dabei farbige 3D-Punktwolken der Unterwasserszenen erstellt. Diese 3D-Karten dienen beispielsweise dem Bediener bei der Fernsteuerung von Unterwasserfahrzeugen und bilden die Grundlage für Offshore-Inspektions- und Vermessungsaufgaben. Die fortschreitende Automatisierung der Messtechnik wird somit auch eine Verwendung durch Nichtfachleute ermöglichen und gleichzeitig die Erfassungszeit erheblich verkürzen und die Genauigkeit verbessern, was die Vermessung im Wasser kostengünstiger und effizienter macht. T3 - Forschungsberichte in der Robotik = Research Notes in Robotics - 28 KW - Selbstkalibrierung KW - Punktwolke KW - Bildverarbeitung KW - 3D Reconstruction KW - Self-calibration KW - Underwater Scanning KW - Underwater Mapping KW - Dreidimensionale Rekonstruktion KW - 3D-Rekonstruktion Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-322693 SN - 978-3-945459-45-4 ER - TY - THES A1 - Borrmann, Dorit T1 - Multi-modal 3D mapping - Combining 3D point clouds with thermal and color information T1 - Multi-modale 3D-Kartierung - Kombination von 3D-Punktwolken mit Thermo- und Farbinformation N2 - Imagine a technology that automatically creates a full 3D thermal model of an environment and detects temperature peaks in it. For better orientation in the model it is enhanced with color information. The current state of the art for analyzing temperature related issues is thermal imaging. It is relevant for energy efficiency but also for securing important infrastructure such as power supplies and temperature regulation systems. Monitoring and analysis of the data for a large building is tedious as stable conditions need to be guaranteed for several hours and detailed notes about the pose and the environment conditions for each image must be taken. For some applications repeated measurements are necessary to monitor changes over time. The analysis of the scene is only possible through expertise and experience. This thesis proposes a robotic system that creates a full 3D model of the environment with color and thermal information by combining thermal imaging with the technology of terrestrial laser scanning. The addition of a color camera facilitates the interpretation of the data and allows for other application areas. The data from all sensors collected at different positions is joined in one common reference frame using calibration and scan matching. The first part of the thesis deals with 3D point cloud processing with the emphasis on accessing point cloud data efficiently, detecting planar structures in the data and registering multiple point clouds into one common coordinate system. The second part covers the autonomous exploration and data acquisition with a mobile robot with the objective to minimize the unseen area in 3D space. Furthermore, the combination of different modalities, color images, thermal images and point cloud data through calibration is elaborated. The last part presents applications for the the collected data. Among these are methods to detect the structure of building interiors for reconstruction purposes and subsequent detection and classification of windows. A system to project the gathered thermal information back into the scene is presented as well as methods to improve the color information and to join separately acquired point clouds and photo series. A full multi-modal 3D model contains all the relevant geometric information about the recorded scene and enables an expert to fully analyze it off-site. The technology clears the path for automatically detecting points of interest thereby helping the expert to analyze the heat flow as well as localize and identify heat leaks. The concept is modular and neither limited to achieving energy efficiency nor restricted to the use in combination with a mobile platform. It also finds its application in fields such as archaeology and geology and can be extended by further sensors. N2 - Man stelle sich eine Technologie vor, die automatisch ein vollständiges 3D-Thermographiemodell einer Umgebung generiert und Temperaturspitzen darin erkennt. Zur besseren Orientierung innerhalb des Modells ist dieses mit Farbinformationen erweitert. In der Analyse temperaturrelevanter Fragestellungen sind Thermalbilder der Stand der Technik. Darunter fallen Energieeffizienz und die Sicherung wichtiger Infrastruktur, wie Energieversorgung und Systeme zur Temperaturregulierung. Die Überwachung und anschließende Analyse der Daten eines großen Gebäudes ist aufwändig, da über mehrere Stunden stabile Bedingungen garantiert und detaillierte Aufzeichnungen über die Aufnahmeposen und die Umgebungsverhältnisse für jedes Wärmebild erstellt werden müssen. Einige Anwendungen erfordern wiederholte Messungen, um Veränderungen über die Zeit zu beobachten. Eine Analyse der Szene ist nur mit Erfahrung und Expertise möglich. Diese Arbeit stellt ein Robotersystem vor, das durch Kombination von Thermographie mit terrestrischem Laserscanning ein vollständiges 3D Modell der Umgebung mit Farb- und Temperaturinformationen erstellt. Die ergänzende Farbkamera vereinfacht die Interpretation der Daten und eröffnet weitere Anwendungsfelder. Die an unterschiedlichen Positionen aufgenommenen Daten aller Sensoren werden durch Kalibrierung und Scanmatching in einem gemeinsamen Bezugssystem zusammengefügt. Der erste Teil der Arbeit behandelt 3D-Punktwolkenverarbeitung mit Schwerpunkt auf effizientem Punktzugriff, Erkennung planarer Strukturen und Registrierung mehrerer Punktwolken in einem gemeinsamen Koordinatensystem. Der zweite Teil beschreibt die autonome Erkundung und Datenakquise mit einem mobilen Roboter, mit dem Ziel, die bisher nicht erfassten Bereiche im 3D-Raum zu minimieren. Des Weiteren wird die Kombination verschiedener Modalitäten, Farbbilder, Thermalbilder und Punktwolken durch Kalibrierung ausgearbeitet. Den abschließenden Teil stellen Anwendungsszenarien für die gesammelten Daten dar, darunter Methoden zur Erkennung der Innenraumstruktur für die Rekonstruktion von Gebäuden und der anschließenden Erkennung und Klassifizierung von Fenstern. Ein System zur Rückprojektion der gesammelten Thermalinformation in die Umgebung wird ebenso vorgestellt wie Methoden zur Verbesserung der Farbinformationen und zum Zusammenfügen separat aufgenommener Punktwolken und Fotoreihen. Ein vollständiges multi-modales 3D Modell enthält alle relevanten geometrischen Informationen der aufgenommenen Szene und ermöglicht einem Experten, diese standortunabhängig zu analysieren. Diese Technologie ebnet den Weg für die automatische Erkennung relevanter Bereiche und für die Analyse des Wärmeflusses und vereinfacht somit die Lokalisierung und Identifikation von Wärmelecks für den Experten. Das vorgestellte modulare Konzept ist weder auf den Anwendungsfall Energieeffizienz beschränkt noch auf die Verwendung einer mobilen Plattform angewiesen. Es ist beispielsweise auch in Feldern wie der Archäologie und Geologie einsetzbar und kann durch zusätzliche Sensoren erweitert werden. T3 - Forschungsberichte in der Robotik = Research Notes in Robotics - 14 KW - Punktwolke KW - Lidar KW - Thermografie KW - Robotik KW - 3D point cloud KW - Laser scanning KW - Robotics KW - 3D thermal mapping KW - Registration Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-157085 SN - 978-3-945459-20-1 SN - 1868-7474 SN - 1868-7466 ER - TY - JOUR A1 - Breves, Priska A1 - Dodel, Nicola T1 - The influence of cybersickness and the media devices’ mobility on the persuasive effects of 360° commercials JF - Multimedia Tools and Applications N2 - With the rise of immersive media, advertisers have started to use 360° commercials to engage and persuade consumers. Two experiments were conducted to address research gaps and to validate the positive impact of 360° commercials in realistic settings. The first study (N = 62) compared the effects of 360° commercials using either a mobile cardboard head-mounted display (HMD) or a laptop. This experiment was conducted in the participants’ living rooms and incorporated individual feelings of cybersickness as a moderator. The participants who experienced the 360° commercial with the HMD reported higher spatial presence and product evaluation, but their purchase intentions were only increased when their reported cybersickness was low. The second experiment (N = 197) was conducted online and analyzed the impact of 360° commercials that were experienced with mobile (smartphone/tablet) or static (laptop/desktop) devices instead of HMDs. The positive effects of omnidirectional videos were stronger when participants used mobile devices. KW - virtual reality KW - immersive advertising KW - spatial presence KW - cybersickness KW - advertising effectiveness Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-269194 SN - 1573-7721 VL - 80 IS - 18 ER - TY - RPRT A1 - Brisch, Fabian A1 - Kassler, Andreas A1 - Vestin, Jonathan A1 - Pieska, Marcus A1 - Amend, Markus T1 - Accelerating Transport Layer Multipath Packet Scheduling for 5G-ATSSS T2 - KuVS Fachgespräch - Würzburg Workshop on Modeling, Analysis and Simulation of Next-Generation Communication Networks 2023 (WueWoWAS’23) N2 - Utilizing multiple access networks such as 5G, 4G, and Wi-Fi simultaneously can lead to increased robustness, resiliency, and capacity for mobile users. However, transparently implementing packet distribution over multiple paths within the core of the network faces multiple challenges including scalability to a large number of customers, low latency, and high-capacity packet processing requirements. In this paper, we offload congestion-aware multipath packet scheduling to a smartNIC. However, such hardware acceleration faces multiple challenges due to programming language and platform limitations. We implement different multipath schedulers in P4 with different complexity in order to cope with dynamically changing path capacities. Using testbed measurements, we show that our CMon scheduler, which monitors path congestion in the data plane and dynamically adjusts scheduling weights for the different paths based on path state information, can process more than 3.5 Mpps packets 25 μs latency. KW - multipath packet scheduling KW - P4 KW - MP-DCCP KW - 5G KW - ATSSSS Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-322052 ER - TY - JOUR A1 - Buchheim, Mark A. A1 - Keller, Alexander A1 - Koetschan, Christian A1 - Förster, Frank A1 - Merget, Benjamin A1 - Wolf, Matthias T1 - Internal Transcribed Spacer 2 (nu ITS2 rRNA) Sequence-Structure Phylogenetics: Towards an Automated Reconstruction of the Green Algal Tree of Life JF - PLoS ONE N2 - Background: Chloroplast-encoded genes (matK and rbcL) have been formally proposed for use in DNA barcoding efforts targeting embryophytes. Extending such a protocol to chlorophytan green algae, though, is fraught with problems including non homology (matK) and heterogeneity that prevents the creation of a universal PCR toolkit (rbcL). Some have advocated the use of the nuclear-encoded, internal transcribed spacer two (ITS2) as an alternative to the traditional chloroplast markers. However, the ITS2 is broadly perceived to be insufficiently conserved or to be confounded by introgression or biparental inheritance patterns, precluding its broad use in phylogenetic reconstruction or as a DNA barcode. A growing body of evidence has shown that simultaneous analysis of nucleotide data with secondary structure information can overcome at least some of the limitations of ITS2. The goal of this investigation was to assess the feasibility of an automated, sequence-structure approach for analysis of IT2 data from a large sampling of phylum Chlorophyta. Methodology/Principal Findings: Sequences and secondary structures from 591 chlorophycean, 741 trebouxiophycean and 938 ulvophycean algae, all obtained from the ITS2 Database, were aligned using a sequence structure-specific scoring matrix. Phylogenetic relationships were reconstructed by Profile Neighbor-Joining coupled with a sequence structure-specific, general time reversible substitution model. Results from analyses of the ITS2 data were robust at multiple nodes and showed considerable congruence with results from published phylogenetic analyses. Conclusions/Significance: Our observations on the power of automated, sequence-structure analyses of ITS2 to reconstruct phylum-level phylogenies of the green algae validate this approach to assessing diversity for large sets of chlorophytan taxa. Moreover, our results indicate that objections to the use of ITS2 for DNA barcoding should be weighed against the utility of an automated, data analysis approach with demonstrated power to reconstruct evolutionary patterns for highly divergent lineages. KW - RBCL Gene-sequences KW - Colonial volvocales chlorophyta KW - 26S RDNA Data KW - Land plants KW - Molecular systematics KW - Secondary structure KW - Nuclear RDNA KW - DNA KW - Barcodes KW - Dasycladales chlorophyta KW - Profile distances Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-140866 VL - 6 IS - 2 ER - TY - JOUR A1 - Buchin, Kevin A1 - Buchin, Maike A1 - Byrka, Jaroslaw A1 - Nöllenburg, Martin A1 - Okamoto, Yoshio A1 - Silveira, Rodrigo I. A1 - Wolff, Alexander T1 - Drawing (Complete) Binary Tanglegrams JF - Algorithmica N2 - A binary tanglegram is a drawing of a pair of rooted binary trees whose leaf sets are in one-to-one correspondence; matching leaves are connected by inter-tree edges. For applications, for example, in phylogenetics, it is essential that both trees are drawn without edge crossings and that the inter-tree edges have as few crossings as possible. It is known that finding a tanglegram with the minimum number of crossings is NP-hard and that the problem is fixed-parameter tractable with respect to that number. We prove that under the Unique Games Conjecture there is no constant-factor approximation for binary trees. We show that the problem is NP-hard even if both trees are complete binary trees. For this case we give an O(n 3)-time 2-approximation and a new, simple fixed-parameter algorithm. We show that the maximization version of the dual problem for binary trees can be reduced to a version of MaxCut for which the algorithm of Goemans and Williamson yields a 0.878-approximation. KW - NP-hardness KW - crossing minimization KW - binary tanglegram KW - approximation algorithm KW - fixed-parameter tractability Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-124622 VL - 62 ER - TY - THES A1 - Budig, Benedikt T1 - Extracting Spatial Information from Historical Maps: Algorithms and Interaction T1 - Extraktion räumlicher Informationen aus historischen Landkarten: Algorithmen und Interaktion N2 - Historical maps are fascinating documents and a valuable source of information for scientists of various disciplines. Many of these maps are available as scanned bitmap images, but in order to make them searchable in useful ways, a structured representation of the contained information is desirable. This book deals with the extraction of spatial information from historical maps. This cannot be expected to be solved fully automatically (since it involves difficult semantics), but is also too tedious to be done manually at scale. The methodology used in this book combines the strengths of both computers and humans: it describes efficient algorithms to largely automate information extraction tasks and pairs these algorithms with smart user interactions to handle what is not understood by the algorithm. The effectiveness of this approach is shown for various kinds of spatial documents from the 16th to the early 20th century. N2 - Historische Landkarten sind faszinierende Dokumente und eine wertvolle Informationsquelle für Wissenschaftler verschiedener Fächer. Viele dieser Karten liegen als gescannte Bitmap-Bilder vor, aber um sie auf nützliche Art durchsuchbar zu machen ist eine strukturierte Repräsentation der enthaltenen Informationen wünschenswert. Dieses Buch beschäftigt sich mit der Extraktion räumlicher Informationen aus historischen Landkarten. Man kann nicht erwarten, dass dies vollautomatisch geschieht (da komplizierte Semantik involviert ist), aber es ist auch zu aufwändig, um im großen Stil manuell durchgeführt zu werden. Die Methodik, die in diesem Buch verwendet wird, kombiniert die Stärken von Computern und Menschen: Es werden effiziente Algorithmen beschrieben, die Extraktionsaufgaben weitgehend automatisieren, und dazu passende Nutzerinteraktionen entworfen, mit denen Fälle gelöst werden, die die Algorithmen nicht vestehen. Die Effekitivität dieses Ansatzes wird anhand verschiedener räumlicher Dokumente aus dem 16. bis frühen 20. Jahrhundert gezeigt. KW - Karte KW - Effizienter Algorithmus KW - Interaktion KW - Information Extraction KW - Smart User Interaction KW - Historical Maps KW - Itineraries KW - Deep Georeferencing KW - Benutzerinteraktion KW - Historische Landkarten KW - Itinerare KW - Georeferenzierung KW - Historische Karte KW - Raumdaten Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-160955 SN - 978-3-95826-092-4 SN - 978-3-95826-093-1 N1 - Parallel erschienen als Druckausgabe in Würzburg University Press, ISBN 978-3-95826-092-4, 32,90 Euro. PB - Würzburg University Press CY - Würzburg ET - 1. Auflage ER - TY - JOUR A1 - Buga, Ana-Maria A1 - Scholz, Claus Jürgen A1 - Kumar, Senthil A1 - Herndon, James G. A1 - Alexandru, Dragos A1 - Cojocaru, Gabriel Radu A1 - Dandekar, Thomas A1 - Popa-Wagner, Aurel T1 - Identification of New Therapeutic Targets by Genome-Wide Analysis of Gene Expression in the Ipsilateral Cortex of Aged Rats after Stroke JF - PLoS One N2 - Background: Because most human stroke victims are elderly, studies of experimental stroke in the aged rather than the young rat model may be optimal for identifying clinically relevant cellular responses, as well for pinpointing beneficial interventions. Methodology/Principal Findings: We employed the Affymetrix platform to analyze the whole-gene transcriptome following temporary ligation of the middle cerebral artery in aged and young rats. The correspondence, heat map, and dendrogram analyses independently suggest a differential, age-group-specific behaviour of major gene clusters after stroke. Overall, the pattern of gene expression strongly suggests that the response of the aged rat brain is qualitatively rather than quantitatively different from the young, i.e. the total number of regulated genes is comparable in the two age groups, but the aged rats had great difficulty in mounting a timely response to stroke. Our study indicates that four genes related to neuropathic syndrome, stress, anxiety disorders and depression (Acvr1c, Cort, Htr2b and Pnoc) may have impaired response to stroke in aged rats. New therapeutic options in aged rats may also include Calcrl, Cyp11b1, Prcp, Cebpa, Cfd, Gpnmb, Fcgr2b, Fcgr3a, Tnfrsf26, Adam 17 and Mmp14. An unexpected target is the enzyme 3-hydroxy-3-methylglutaryl-Coenzyme A synthase 1 in aged rats, a key enzyme in the cholesterol synthesis pathway. Post-stroke axonal growth was compromised in both age groups. Conclusion/Significance: We suggest that a multi-stage, multimodal treatment in aged animals may be more likely to produce positive results. Such a therapeutic approach should be focused on tissue restoration but should also address other aspects of patient post-stroke therapy such as neuropathic syndrome, stress, anxiety disorders, depression, neurotransmission and blood pressure. KW - gamma KW - corticotropin-releasing hormone KW - colony-stimulating factor KW - cerebral ischemia KW - receptor KW - brain KW - protein KW - inhibitor KW - mouse KW - differentiation Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-130657 VL - 7 IS - 12 ER - TY - THES A1 - Busch, Stephan T1 - Robust, Flexible and Efficient Design for Miniature Satellite Systems T1 - Moderne Kleinstsatelliten - Zwischen Robustheit, Flexibilität und Effizienz N2 - Small satellites contribute significantly in the rapidly evolving innovation in space engineering, in particular in distributed space systems for global Earth observation and communication services. Significant mass reduction by miniaturization, increased utilization of commercial high-tech components, and in particular standardization are the key drivers for modern miniature space technology. This thesis addresses key fields in research and development on miniature satellite technology regarding efficiency, flexibility, and robustness. Here, these challenges are addressed by the University of Wuerzburg’s advanced pico-satellite bus, realizing a generic modular satellite architecture and standardized interfaces for all subsystems. The modular platform ensures reusability, scalability, and increased testability due to its flexible subsystem interface which allows efficient and compact integration of the entire satellite in a plug-and-play manner. Beside systematic design for testability, a high degree of operational robustness is achieved by the consequent implementation of redundancy of crucial subsystems. This is combined with efficient fault detection, isolation and recovery mechanisms. Thus, the UWE-3 platform, and in particular the on-board data handling system and the electrical power system, offers one of the most efficient pico-satellite architectures launched in recent years and provides a solid basis for future extensions. The in-orbit performance results of the pico-satellite UWE-3 are presented and summarize successful operations since its launch in 2013. Several software extensions and adaptations have been uploaded to UWE-3 increasing its capabilities. Thus, a very flexible platform for in-orbit software experiments and for evaluations of innovative concepts was provided and tested. N2 - Miniaturisierte Satellitensysteme übernehmen zunehmend eine entscheidende Rolle in der fortschreitenden Globalisierung und Demokratisierung der Raumfahrt. Großes Innovationspotential und neue Kommerzialisierungschancen verspricht der effektive Einsatz von Kleinstsatelliten in zukünftigen fraktionierten Missionen für Erdbeobachtungs- und Kommunikationsanwendungen. Basierend auf vielen kleinen kooperierenden Systemen können diese Systeme zukünftig große multifunktionale Satelliten ergänzen oder ersetzen. Die Herausforderung bei der Entwicklung miniaturisierter Satellitensysteme ist die Gratwanderung zwischen der im Rahmen der Miniaturisierung notwendigen Effizienz, der für die Erfüllung der Mission geforderten Zuverlässigkeit und der wünschenswerten Wiederverwendbarkeit und Erweiterbarkeit zur Realisierung agiler Kleinstsatellitenserien. Diese Arbeit adressiert verschiedene Aspekte für den optimalen Entwurf robuster, flexibler und effizienter Kleinstsatelliten am Beispiel des UWE Pico-Satelliten Bus der Universität Würzburg. Mit dem Ziel der Entwicklung einer soliden Basisplattform für zukünftige Kleinstsatelliten-Formationen wurden entsprechende Designansätze im Rahmen des UWE-3 Projektes in einem integralen Designansatz konsistent umgesetzt. Neben der Entwicklung von effizienten Redundanzkonzepten mit minimalem Overhead für den optimalen Betrieb auf Ressourcen-limitierten Kleinstsatelliten wurde ein modularer Satellitenbus entworfen, der als eine robuste und erweiterbare Basis für zukünftige Missionen dienen soll. Damit realisiert UWE-3 eine der effizientesten Kleinstsatelliten-Architekturen die in den letzten Jahren in den Orbit gebracht wurde. Dargestellte Missionsergebnisse fassen den erfolgreichen Betrieb des Satelliten seit seinem Launch in Jahr 2013 zusammen. T3 - Forschungsberichte in der Robotik = Research Notes in Robotics - 11 KW - Kleinsatellit KW - Fehlertoleranz KW - Miniaturisierung KW - Modularität KW - Picosatellite KW - Satellit Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-136523 SN - 978-3-945459-10-2 ER - TY - THES A1 - Böhler, Elmar T1 - Algebraic closures in complexity theory T1 - Algebraische Hüllen in der Komplexitätstheorie N2 - We use algebraic closures and structures which are derived from these in complexity theory. We classify problems with Boolean circuits and Boolean constraints according to their complexity. We transfer algebraic structures to structural complexity. We use the generation problem to classify important complexity classes. N2 - Algebraische Hüllen und Strukturen, die mit solchen zusammenhängen, werden für die Komplexitätstheorie genutzt. Es werden Probleme im Zusammenhang mit Booleschen Schaltkreisen und Constraint-Satisfaction Problemen komplexitätstheoretisch klassifiziert. Strukturen aus der Algebra werden auf die Strukturelle Komplexität übertragen. Das Generierungsproblem, wird zur Klassifikation wichtiger Komplexitätsklassen benutzt. KW - Komplexitätstheorie KW - Komplexitätstheorie KW - Clones KW - Generierungsproblem KW - Postsche Klassen KW - Complexity Theory KW - Clones KW - Generation Problem KW - Post's Classes Y1 - 2005 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-16106 ER - TY - JOUR A1 - Böhler, Elmar A1 - Creignou, Nadia A1 - Galota, Matthias A1 - Reith, Steffen A1 - Schnoor, Henning A1 - Vollmer, Heribert T1 - Complexity Classifications for Different Equivalence and Audit Problems for Boolean Circuits JF - Logical Methods in Computer Science N2 - We study Boolean circuits as a representation of Boolean functions and conskier different equivalence, audit, and enumeration problems. For a number of restricted sets of gate types (bases) we obtain efficient algorithms, while for all other gate types we show these problems are at least NP-hard. KW - hierarchy KW - satisfiability problems Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-131121 VL - 8 IS - 3:27 SP - 1 EP - 25 ER - TY - JOUR A1 - Caliskan, Aylin A1 - Crouch, Samantha A. W. A1 - Giddins, Sara A1 - Dandekar, Thomas A1 - Dangwal, Seema T1 - Progeria and aging — Omics based comparative analysis JF - Biomedicines N2 - Since ancient times aging has also been regarded as a disease, and humankind has always strived to extend the natural lifespan. Analyzing the genes involved in aging and disease allows for finding important indicators and biological markers for pathologies and possible therapeutic targets. An example of the use of omics technologies is the research regarding aging and the rare and fatal premature aging syndrome progeria (Hutchinson-Gilford progeria syndrome, HGPS). In our study, we focused on the in silico analysis of differentially expressed genes (DEGs) in progeria and aging, using a publicly available RNA-Seq dataset (GEO dataset GSE113957) and a variety of bioinformatics tools. Despite the GSE113957 RNA-Seq dataset being well-known and frequently analyzed, the RNA-Seq data shared by Fleischer et al. is far from exhausted and reusing and repurposing the data still reveals new insights. By analyzing the literature citing the use of the dataset and subsequently conducting a comparative analysis comparing the RNA-Seq data analyses of different subsets of the dataset (healthy children, nonagenarians and progeria patients), we identified several genes involved in both natural aging and progeria (KRT8, KRT18, ACKR4, CCL2, UCP2, ADAMTS15, ACTN4P1, WNT16, IGFBP2). Further analyzing these genes and the pathways involved indicated their possible roles in aging, suggesting the need for further in vitro and in vivo research. In this paper, we (1) compare “normal aging” (nonagenarians vs. healthy children) and progeria (HGPS patients vs. healthy children), (2) enlist genes possibly involved in both the natural aging process and progeria, including the first mention of IGFBP2 in progeria, (3) predict miRNAs and interactomes for WNT16 (hsa-mir-181a-5p), UCP2 (hsa-mir-26a-5p and hsa-mir-124-3p), and IGFBP2 (hsa-mir-124-3p, hsa-mir-126-3p, and hsa-mir-27b-3p), (4) demonstrate the compatibility of well-established R packages for RNA-Seq analysis for researchers interested but not yet familiar with this kind of analysis, and (5) present comparative proteomics analyses to show an association between our RNA-Seq data analyses and corresponding changes in protein expression. KW - progeria KW - aging KW - omics KW - RNA sequencing KW - bioinformatics KW - sun exposure KW - HGPS KW - IGFBP2 KW - ACKR4 KW - WNT Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-289868 SN - 2227-9059 VL - 10 IS - 10 ER - TY - JOUR A1 - Carolus, Astrid A1 - Wienrich, Carolin A1 - Törke, Anna A1 - Friedel, Tobias A1 - Schwietering, Christian A1 - Sperzel, Mareike T1 - ‘Alexa, I feel for you!’ Observers’ empathetic reactions towards a conversational agent JF - Frontiers in Computer Science N2 - Conversational agents and smart speakers have grown in popularity offering a variety of options for use, which are available through intuitive speech operation. In contrast to the standard dyad of a single user and a device, voice-controlled operations can be observed by further attendees resulting in new, more social usage scenarios. Referring to the concept of ‘media equation’ and to research on the idea of ‘computers as social actors,’ which describes the potential of technology to trigger emotional reactions in users, this paper asks for the capacity of smart speakers to elicit empathy in observers of interactions. In a 2 × 2 online experiment, 140 participants watched a video of a man talking to an Amazon Echo either rudely or neutrally (factor 1), addressing it as ‘Alexa’ or ‘Computer’ (factor 2). Controlling for participants’ trait empathy, the rude treatment results in participants’ significantly higher ratings of empathy with the device, compared to the neutral treatment. The form of address had no significant effect. Results were independent of the participants’ gender and usage experience indicating a rather universal effect, which confirms the basic idea of the media equation. Implications for users, developers and researchers were discussed in the light of (future) omnipresent voice-based technology interaction scenarios. KW - conversational agent KW - empathy KW - smart speaker KW - media equation KW - computers as social actors KW - human-computer interaction Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-258807 VL - 3 ER - TY - INPR A1 - Dandekar, Thomas T1 - Biological heuristics applied to cosmology suggests a condensation nucleus as start of our universe and inflation cosmology replaced by a period of rapid Weiss domain-like crystal growth N2 - Cosmology often uses intricate formulas and mathematics to derive new theories and concepts. We do something different in this paper: We look at biological processes and derive from these heuristics so that the revised cosmology agrees with astronomical observations but does also agree with standard biological observations. We show that we then have to replace any type of singularity at the start of the universe by a condensation nucleus and that the very early period of the universe usually assumed to be inflation has to be replaced by a period of rapid crystal growth as in Weiss magnetization domains. Impressively, these minor modifications agree well with astronomical observations including removing the strong inflation perturbations which were never observed in the recent BICEP2 experiments. Furthermore, looking at biological principles suggests that such a new theory with a condensation nucleus at start and a first rapid phase of magnetization-like growth of the ordered, physical laws obeying lattice we live in is in fact the only convincing theory of the early phases of our universe that also is compatible with current observations. We show in detail in the following that such a process of crystal creation, breaking of new crystal seeds and ultimate evaporation of the present crystal readily leads over several generations to an evolution and selection of better, more stable and more self-organizing crystals. Moreover, this explains the “fine-tuning” question why our universe is fine-tuned to favor life: Our Universe is so self-organizing to have enough offspring and the detailed physics involved is at the same time highly favorable for all self-organizing processes including life. This biological theory contrasts with current standard inflation cosmologies. The latter do not perform well in explaining any phenomena of sophisticated structure creation or self-organization. As proteins can only thermodynamically fold by increasing the entropy in the solution around them we suggest for cosmology a condensation nucleus for a universe can form only in a “chaotic ocean” of string-soup or quantum foam if the entropy outside of the nucleus rapidly increases. We derive an interaction potential for 1 to n-dimensional strings or quantum-foams and show that they allow only 1D, 2D, 4D or octonion interactions. The latter is the richest structure and agrees to the E8 symmetry fundamental to particle physics and also compatible with the ten dimensional string theory E8 which is part of the M-theory. Interestingly, any other interactions of other dimensionality can be ruled out using Hurwitz compositional theorem. Crystallization explains also extremely well why we have only one macroscopic reality and where the worldlines of alternative trajectories exist: They are in other planes of the crystal and for energy reasons they crystallize mostly at the same time, yielding a beautiful and stable crystal. This explains decoherence and allows to determine the size of Planck´s quantum h (very small as separation of crystal layers by energy is extremely strong). Ultimate dissolution of real crystals suggests an explanation for dark energy agreeing with estimates for the “big rip”. The halo distribution of dark matter favoring galaxy formation is readily explained by a crystal seed starting with unit cells made of normal and dark matter. That we have only matter and not antimatter can be explained as there may be right handed mattercrystals and left-handed antimatter crystals. Similarly, real crystals are never perfect and we argue that exactly such irregularities allow formation of galaxies, clusters and superclusters. Finally, heuristics from genetics suggest to look for a systems perspective to derive correct vacuum and Higgs Boson energies. KW - heuristics KW - inflation KW - cosmology KW - crystallization KW - crystal growth KW - E8 symmetry KW - Hurwitz theorem KW - evolution KW - Lee Smolin Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-183945 ER - TY - INPR A1 - Dandekar, Thomas T1 - Analysing the phase space of the standard model and its basic four forces from a qubit phase transition perspective: implications for large-scale structure generation and early cosmological events N2 - The phase space for the standard model of the basic four forces for n quanta includes all possible ensemble combinations of their quantum states m, a total of n**m states. Neighbor states reach according to transition possibilities (S-matrix) with emergent time from entropic ensemble gradients. We replace the “big bang” by a condensation event (interacting qubits become decoherent) and inflation by a crystallization event – the crystal unit cell guarantees same symmetries everywhere. Interacting qubits solidify and form a rapidly growing domain where the n**m states become separated ensemble states, rising long-range forces stop ultimately further growth. After that very early events, standard cosmology with the hot fireball model takes over. Our theory agrees well with lack of inflation traces in cosmic background measurements, large-scale structure of voids and filaments, supercluster formation, galaxy formation, dominance of matter and life-friendliness. We prove qubit interactions to be 1,2,4 or 8 dimensional (agrees with E8 symmetry of our universe). Repulsive forces at ultrashort distances result from quantization, long-range forces limit crystal growth. Crystals come and go in the qubit ocean. This selects for the ability to lay seeds for new crystals, for self-organization and life-friendliness. We give energy estimates for free qubits vs bound qubits, misplacements in the qubit crystal and entropy increase during qubit decoherence / crystal formation. Scalar fields for color interaction and gravity derive from the permeating qubit-interaction field. Hence, vacuum energy gets low only inside the qubit crystal. Condensed mathematics may advantageously model free / bound qubits in phase space. KW - phase space KW - cosmology KW - emergent time KW - qubit KW - phase transition KW - bit Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-298580 ER - TY - THES A1 - Dang, Nghia Duc T1 - Konzeption und Evaluation eines hybriden, skalierbaren Werkzeugs zur mechatronischen Systemdiagnose am Beispiel eines Diagnosesystems für freie Kfz-Werkstätten T1 - Conception and evaluation of a hybrid, scalable tool for mechatronical system diagnosis on the example of a diagnostic system for independent car repair shops N2 - Die Entwicklung eines wissensbasierten Systems, speziell eines Diagnosesystems, ist eine Teildisziplin der künstlichen Intelligenz und angewandten Informatik. Im Laufe der Forschung auf diesem Gebiet wurden verschiedene Lösungsansätze mit unterschiedlichem Erfolg bei der Anwendung in der Kraftfahrzeugdiagnose entwickelt. Diagnosesysteme in Vertragswerkstätten, das heißt in Fahrzeughersteller gebundenen Werkstätten, wenden hauptsächlich die fallbasierte Diagnostik an. Zum einen hält sich hier die Fahrzeugvielfalt in Grenzen und zum anderen besteht eine Meldepflicht bei neuen, nicht im System vorhandenen Fällen. Die freien Werkstätten verfügen nicht über eine solche Datenbank. Somit ist der fallbasierte Ansatz schwer umsetzbar. In freien Werkstätten - Fahrzeughersteller unabhängigen Werkstätten - basiert die Fehlersuche hauptsächlich auf Fehlerbäumen. Wegen der wachsenden Fahrzeugkomplexität, welche wesentlich durch die stark zunehmende Anzahl der durch mechatronische Systeme realisierten Funktionen bedingt ist, und der steigenden Typenvielfalt ist die geführte Fehlersuche in freien Werkstätten nicht immer zielführend. Um die Unterstützung des Personals von freien Werkstätten bei der zukünftigen Fehlersuche zu gewährleisten, werden neue Generationen von herstellerunabhängigen Diagnosetools benötigt, die die Probleme der Variantenvielfalt und Komplexität lösen. In der vorliegenden Arbeit wird ein Lösungsansatz vorgestellt, der einen qualitativen, modellbasierten Diagnoseansatz mit einem auf heuristischem Diagnosewissen basierenden Ansatz vereint. Neben der Grundlage zur Wissenserhebung werden in dieser Arbeit die theoretische Grundlage zur Beherrschung der Variantenvielfalt sowie die Tests für die erstellten Diagnosemodelle behandelt. Die Diagnose ist symptombasiert und die Inferenzmechanismen zur Verarbeitung des Diagnosewissens sind eine Kombination aus Propagierung der abweichenden physikalischen Größen im Modell und der Auswertung des heuristischen Wissens. Des Weiteren werden in dieser Arbeit verschiedene Aspekte der Realisierung der entwickelten theoretischen Grundlagen dargestellt, zum Beispiel: Systemarchitektur, Wissenserhebungsprozess, Ablauf des Diagnosevorgangs in den Werkstätten. Die Evaluierung der entwickelten Lösung bei der Wissenserhebung in Form von Modellerstellungen und Modellierungsworkshops sowie Feldtests dient nicht nur zur Bestätigung des entwickelten Ansatzes, sondern auch zur Ideenfindung für die Integration der entwickelten Tools in die existierende IT-Infrastruktur. N2 - The development of a knowledge-based system - in particular a diagnostic system - is a branch of artificial intelligence and applied computer science. Throughout the research in this field, various approaches have been developed with varying degrees of success in the application in automotive diagnostics. Diagnostic systems in authorized garages i.e. in garages bound to vehicle manufacturers mainly apply case-based diagnosis. In those cases first the variance of vehicles is limited and second there is a reporting obligation of new, yet not existing cases within the system. The independent repair shops do not have such a database. Thus, the case-based approach is difficult to implement. In independent garages - car manufacturer independent garages - the troubleshooting is mainly based on fault trees. Because of the growing complexity of vehicles, which is mainly due to the rapidly increasing number of functions realized by mechatronic systems and the increasing variety of vehicle types, guided troubleshooting for independent garages is not always productive. To ensure the support of the staff of independent garages in the future troubleshooting, new generations of multivendor diagnostic tools are needed to solve the problems of the variety and complexity. In the present paper an approach is presented which combines a qualitative, model-based diagnostic approach to a heuristic diagnostic knowledge-based approach. In addition to the basis for knowledge collection in this study the theoretical basis for the control of the variety and the tests for the generated diagnosis models are discussed. The diagnosis is symptom-based and the inference mechanisms for processing of diagnostic knowledge are a combination of propagation of the different physical parameters in the model and the evaluation of heuristic knowledge. Furthermore, various aspects of the implementation of the developed theoretical basis are presented in this thesis, for example: system architecture, knowledge collection process, the course of action of the diagnostic process in the workshops. The evaluation of the developed solution for the collection of knowledge in the form of preparation of models and modeling workshops, as well as field tests not only serves to validate the developed approach, but also to find ideas for the integration of the developed tools into the existing IT infrastructure. KW - Diagnosesystem KW - Künstliche Intelligenz KW - Modellbasierte Diagnose KW - Werkstattdiagnose KW - hybride Diagnose KW - skalierbare Diagnose KW - Inferenz KW - Angewandte Informatik KW - aftermarket diagnostic KW - model-base diagnosis KW - hybrid Diagnostic Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-70774 ER - TY - JOUR A1 - Davidson, Padraig A1 - Düking, Peter A1 - Zinner, Christoph A1 - Sperlich, Billy A1 - Hotho, Andreas T1 - Smartwatch-Derived Data and Machine Learning Algorithms Estimate Classes of Ratings of Perceived Exertion in Runners: A Pilot Study JF - Sensors N2 - The rating of perceived exertion (RPE) is a subjective load marker and may assist in individualizing training prescription, particularly by adjusting running intensity. Unfortunately, RPE has shortcomings (e.g., underreporting) and cannot be monitored continuously and automatically throughout a training sessions. In this pilot study, we aimed to predict two classes of RPE (≤15 “Somewhat hard to hard” on Borg’s 6–20 scale vs. RPE >15 in runners by analyzing data recorded by a commercially-available smartwatch with machine learning algorithms. Twelve trained and untrained runners performed long-continuous runs at a constant self-selected pace to volitional exhaustion. Untrained runners reported their RPE each kilometer, whereas trained runners reported every five kilometers. The kinetics of heart rate, step cadence, and running velocity were recorded continuously ( 1 Hz ) with a commercially-available smartwatch (Polar V800). We trained different machine learning algorithms to estimate the two classes of RPE based on the time series sensor data derived from the smartwatch. Predictions were analyzed in different settings: accuracy overall and per runner type; i.e., accuracy for trained and untrained runners independently. We achieved top accuracies of 84.8 % for the whole dataset, 81.8 % for the trained runners, and 86.1 % for the untrained runners. We predict two classes of RPE with high accuracy using machine learning and smartwatch data. This approach might aid in individualizing training prescriptions. KW - artificial intelligence KW - endurance KW - exercise intensity KW - precision training KW - prediction KW - wearable Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-205686 SN - 1424-8220 VL - 20 IS - 9 ER - TY - CHAP A1 - Davies, Richard A1 - Dewell, Nathan A1 - Harvey, Carlo T1 - A framework for interactive, autonomous and semantic dialogue generation in games T2 - Proceedings of the 1st Games Technology Summit N2 - Immersive virtual environments provide users with the opportunity to escape from the real world, but scripted dialogues can disrupt the presence within the world the user is trying to escape within. Both Non-Playable Character (NPC) to Player and NPC to NPC dialogue can be non-natural and the reliance on responding with pre-defined dialogue does not always meet the players emotional expectations or provide responses appropriate to the given context or world states. This paper investigates the application of Artificial Intelligence (AI) and Natural Language Processing to generate dynamic human-like responses within a themed virtual world. Each thematic has been analysed against humangenerated responses for the same seed and demonstrates invariance of rating across a range of model sizes, but shows an effect of theme and the size of the corpus used for fine-tuning the context for the game world. KW - natural language processing · · · KW - interactive authoring system KW - semantic understanding KW - artificial intelligence Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-246023 ER - TY - RPRT A1 - Deutschmann, Jörg A1 - Hielscher, Kai-Steffen A1 - German, Reinhard T1 - Next-Generation Satellite Communication Networks T2 - Würzburg Workshop on Next-Generation Communication Networks (WueWoWas'22) N2 - This paper gives an overview of our recent activities in the field of satellite communication networks, including an introduction to geostationary satellite systems and Low Earth Orbit megaconstellations. To mitigate the high latencies of geostationary satellite networks, TCP-splitting Performance Enhancing Proxies are deployed. However, these cannot be applied in the case of encrypted transport headers as it is the case for VPNs or QUIC. We summarize performance evaluation results from multiple measurement campaigns. In a recently concluded project, multipath communication was used to combine the advantages of very heterogeneous communication paths: low data rate, low latency (e.g., DSL light) and high data rate, high latency (e.g., geostationary satellite). KW - Datennetz KW - satellite communication KW - Performance Enhancing Proxies KW - transport protocols KW - VPN KW - QUIC KW - multipath communication KW - hybrid access Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-280732 ER - TY - JOUR A1 - Djebko, Kirill A1 - Puppe, Frank A1 - Kayal, Hakan T1 - Model-based fault detection and diagnosis for spacecraft with an application for the SONATE triple cube nano-satellite JF - Aerospace N2 - The correct behavior of spacecraft components is the foundation of unhindered mission operation. However, no technical system is free of wear and degradation. A malfunction of one single component might significantly alter the behavior of the whole spacecraft and may even lead to a complete mission failure. Therefore, abnormal component behavior must be detected early in order to be able to perform counter measures. A dedicated fault detection system can be employed, as opposed to classical health monitoring, performed by human operators, to decrease the response time to a malfunction. In this paper, we present a generic model-based diagnosis system, which detects faults by analyzing the spacecraft’s housekeeping data. The observed behavior of the spacecraft components, given by the housekeeping data is compared to their expected behavior, obtained through simulation. Each discrepancy between the observed and the expected behavior of a component generates a so-called symptom. Given the symptoms, the diagnoses are derived by computing sets of components whose malfunction might cause the observed discrepancies. We demonstrate the applicability of the diagnosis system by using modified housekeeping data of the qualification model of an actual spacecraft and outline the advantages and drawbacks of our approach. KW - fault detection KW - model-based diagnosis KW - nano-satellite Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-198836 SN - 2226-4310 VL - 6 IS - 10 ER - TY - THES A1 - Driewer, Frauke T1 - Teleoperation Interfaces in Human-Robot Teams T1 - Benutzerschnittstellen für Teleoperation in Mensch-Roboter Teams N2 - Diese Arbeit beschäftigt sich mit der Verbesserung von Mensch-Roboter Interaktion in Mensch-Roboter Teams für Teleoperation Szenarien, wie z.B. robotergestützte Feuerwehreinsätze. Hierbei wird ein Konzept und eine Architektur für ein System zur Unterstützung von Teleoperation von Mensch-Roboter Teams vorgestellt. Die Anforderungen an Informationsaustausch und -verarbeitung, insbesondere für die Anwendung Rettungseinsatz, werden ausgearbeitet. Weiterhin wird das Design der Benutzerschnittstellen für Mensch-Roboter Teams dargestellt und Prinzipien für Teleoperation-Systeme und Benutzerschnittstellen erarbeitet. Alle Studien und Ansätze werden in einem Prototypen-System implementiert und in verschiedenen Benutzertests abgesichert. Erweiterungsmöglichkeiten zum Einbinden von 3D Sensordaten und die Darstellung auf Stereovisualisierungssystemen werden gezeigt. N2 - This work deals with teams in teleoperation scenarios, where one human team partner (supervisor) guides and controls multiple remote entities (either robotic or human) and coordinates their tasks. Such a team needs an appropriate infrastructure for sharing information and commands. The robots need to have a level of autonomy, which matches the assigned task. The humans in the team have to be provided with autonomous support, e.g. for information integration. Design and capabilities of the human-robot interfaces will strongly influence the performance of the team as well as the subjective feeling of the human team partners. Here, it is important to elaborate the information demand as well as how information is presented. Such human-robot systems need to allow the supervisor to gain an understanding of what is going on in the remote environment (situation awareness) by providing the necessary information. This includes achieving fast assessment of the robot´s or remote human´s state. Processing, integration and organization of data as well as suitable autonomous functions support decision making and task allocation and help to decrease the workload in this multi-entity teleoperation task. Interaction between humans and robots is improved by a common world model and a responsive system and robots. The remote human profits from a simplified user interface providing exactly the information needed for the actual task at hand. The topic of this thesis is the investigation of such teleoperation interfaces in human-robot teams, especially for high-risk, time-critical, and dangerous tasks. The aim is to provide a suitable human-robot team structure as well as analyze the demands on the user interfaces. On one side, it will be looked on the theoretical background (model, interactions, and information demand). On the other side, real implementations for system, robots, and user interfaces are presented and evaluated as testbeds for the claimed requirements. Rescue operations, more precisely fire-fighting, was chosen as an exemplary application scenario for this work. The challenges in such scenarios are high (highly dynamic environments, high risk, time criticality etc.) and it can be expected that results can be transferred to other applications, which have less strict requirements. The present work contributes to the introduction of human-robot teams in task-oriented scenarios, such as working in high risk domains, e.g. fire-fighting. It covers the theoretical background of the required system, the analysis of related human factors concepts, as well as discussions on implementation. An emphasis is placed on user interfaces, their design, requirements and user testing, as well as on the used techniques (three-dimensional sensor data representation, mixed reality, and user interface design guidelines). Further, the potential integration of 3D sensor data as well as the visualization on stereo visualization systems is introduced. T3 - Forschungsberichte in der Robotik = Research Notes in Robotics - 1 KW - Robotik KW - Mobiler Roboter KW - Autonomer Roboter KW - Mensch-Maschine-System KW - Mensch-Maschine-Schnittstelle KW - Mixed Reality KW - Mensch-Roboter-Interaktion KW - Situationsbewusstsein KW - Teleoperation KW - Benutzerschnittstelle KW - Rettungsroboter KW - Human-Robot-Interaction KW - Situation Awareness KW - Teleoperation KW - User Interface KW - Search-and-Rescue Y1 - 2008 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-36351 SN - 978-3-923959-57-0 N1 - Zugl. gedruckte Ausgabe: ISBN: 978-3-923959-54-9 (Paper) ER - TY - JOUR A1 - Du, Shitong A1 - Lauterbach, Helge A. A1 - Li, Xuyou A1 - Demisse, Girum G. A1 - Borrmann, Dorit A1 - Nüchter, Andreas T1 - Curvefusion — A Method for Combining Estimated Trajectories with Applications to SLAM and Time-Calibration JF - Sensors N2 - Mapping and localization of mobile robots in an unknown environment are essential for most high-level operations like autonomous navigation or exploration. This paper presents a novel approach for combining estimated trajectories, namely curvefusion. The robot used in the experiments is equipped with a horizontally mounted 2D profiler, a constantly spinning 3D laser scanner and a GPS module. The proposed algorithm first combines trajectories from different sensors to optimize poses of the planar three degrees of freedom (DoF) trajectory, which is then fed into continuous-time simultaneous localization and mapping (SLAM) to further improve the trajectory. While state-of-the-art multi-sensor fusion methods mainly focus on probabilistic methods, our approach instead adopts a deformation-based method to optimize poses. To this end, a similarity metric for curved shapes is introduced into the robotics community to fuse the estimated trajectories. Additionally, a shape-based point correspondence estimation method is applied to the multi-sensor time calibration. Experiments show that the proposed fusion method can achieve relatively better accuracy, even if the error of the trajectory before fusion is large, which demonstrates that our method can still maintain a certain degree of accuracy in an environment where typical pose estimation methods have poor performance. In addition, the proposed time-calibration method also achieves high accuracy in estimating point correspondences. KW - mapping KW - continuous-time SLAM KW - deformation-based method KW - time calibration Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-219988 SN - 1424-8220 VL - 20 IS - 23 ER - TY - THES A1 - Duelli, Michael T1 - Heuristic Design and Provisioning of Resilient Multi-Layer Networks T1 - Heuristische Planung und Betrieb von ausfallsicheren Mehrschichtnetzen N2 - To jointly provide different services/technologies, like IP and Ethernet or IP and SDH/SONET, in a single network, equipment of multiple technologies needs to be deployed to the sites/Points of Presence (PoP) and interconnected with each other. Therein, a technology may provide transport functionality to other technologies and increase the number of available resources by using multiplexing techniques. By providing its own switching functionality, each technology creates connections in a logical layer which leads to the notion of multi-layer networks. The design of such networks comprises the deployment and interconnection of components to suit to given traffic demands. To prevent traffic loss due to failures of networking equipment, protection mechanisms need to be established. In multi-layer networks, protection usually can be applied in any of the considered layers. In turn, the hierarchical structure of multi-layer networks also bears shared risk groups (SRG). To achieve a cost-optimal resilient network, an appropriate combination of multiplexing techniques, technologies, and their interconnections needs to be found. Thus, network design is a combinatorial problem with a large parameter and solution space. After the design stage, the resources of a multi-layer network can be provided to traffic demands. Especially, dynamic capacity provisioning requires interaction of sites and layers, as well as accurate retrieval of constraint information. In recent years, generalized multiprotocol label switching (GMPLS) and path computation elements (PCE) have emerged as possible approaches for these challenges. Like the design, the provisioning of multi-layer networks comprises a variety of optimization parameters, like blocking probability, resilience, and energy efficiency. In this work, we introduce several efficient heuristics to approach the considered optimization problems. We perform capital expenditure (CAPEX)-aware design of multi-layer networks from scratch, based on IST NOBEL phase 2 project's cost and equipment data. We comprise traffic and resilience requirements in different and multiple layers as well as different network architectures. On top of the designed networks, we consider the dynamic provisioning of multi-layer traffic based on the GMPLS and PCE architecture. We evaluate different PCE deployments, information retrieval strategies, and re-optimization. Finally, we show how information about provisioning utilization can be used to provide a feedback for network design. N2 - Um in einem Netz verschiedene Dienste/Schichten, z.B. IP und Ethernet oder IP und SDH/SONET, parallel anbieten zu können, müssen Komponenten mehrerer Technologien an den Standorten verbaut und miteinander verbunden werden. Hierbei kann eine Technologie eine Transportschicht für andere Technologien fungieren und die Zahl der verfügbaren Ressourcen durch Multiplex Techniken erhöhen. Durch die Bereitstellung eigener Switching Funktionalität erzeugt jede Technologie Verbindungen in einer logischen Schicht. Dies führt zu der Bezeichnung Mehrschichtnetz (engl. multi-layer network). Die Planung solcher Netze hat das Verbauen und Verbinden von Komponenten zum Ziel, so dass gegebene Verkehrsströme realisiert werden können. Um Unterbrechungen der Verkehrsströme aufgrund von Fehlern in den Netzkomponenten zu verhinden, müssen Schutzmechanismen eingebaut werden. In Mehrschichtnetzen können solche Schutzmechanismen in jeder beliebigen Schicht betrachtet werden. Allerdings birgt die hierarchische Struktur von Mehrschichtnetzen das Risiko von shared risk groups (SRG). Um ein Kosten-optimales ausfallsicheres Netz zu erhalten, muss eine passende Kombination aus Multiplex Techniken, Technologien und deren Verbindungen gefunden werden. Die Netzplanung ist daher ein kombinatorisches Problem mit einem großen Parameter- und Lösungsraum. Nach der Planungsphase können die Ressourcen eines Mehrschichtnetzes für Verkehrsströme vorgehalten werden. Die Betrachtung von dynamischer Kapazitätsanforderungen erfordert die Interaktion von Knoten und Schichten sowie akkurate Gewinnung von Informationen zur Auslastung. In jüngster Zeit sind das Generalized Multiprotocol Label Switching (GMPLS) und das Path Computation Element (PCE) als mögliche Lösungsansätze für diese Herausforderungen entstanden. Wie in der Planung beinhaltet auch der Betrieb von Mehrschichtnetzen eine Vielzahl von Optimierungsparametern, wie die Blockierungswahrscheinlichkeit, Ausfallsicherheit und Energie-Effizienz. In dieser Arbeit, führen wir verschiedene effiziente Heuristiken ein, um die betrachteten Optimierungsprobleme anzugehen. Wir planen Mehrschichtnetze von Grund auf und minimieren hinsichtlich der Anschaffungskosten basierend auf den Kosten- und Komponenten-Daten des IST NOBEL Phase 2 Projekts. Wir berücksichtigen Anforderungen der Verkehrsströme und Ausfallsicherheit in verschiedenen Schichten und in mehreren Schichten gleichzeitig sowie verschiedene Netzarchitekturen. Aufsetzend auf dem geplanten Netz betrachten wir den Betrieb von Mehrschichtnetzen mit dynamischen Verkehr basiert auf der GMPLS und PCE Architektur. Wir bewerten verschiedene PCE Installationen, Strategien zur Informationsgewinnung und Re-Optimierung. Abschließend, zeigen wir wie Information über die Auslastung im Betrieb genutzt werden kann um Rückmeldung an die Netzplanung zu geben. T3 - Würzburger Beiträge zur Leistungsbewertung Verteilter Systeme - 02/12 KW - Mehrschichtsystem KW - Planung KW - Ressourcenmanagement KW - Ausfallsicheres System KW - Mehrschichtnetze KW - Pfadberechnungselement KW - Ausfallsicherheit KW - Multi-Layer KW - Design KW - Resilience KW - Resource Management KW - Path Computation Element Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-69433 ER - TY - JOUR A1 - Dumic, Emil A1 - Bjelopera, Anamaria A1 - Nüchter, Andreas T1 - Dynamic point cloud compression based on projections, surface reconstruction and video compression JF - Sensors N2 - In this paper we will present a new dynamic point cloud compression based on different projection types and bit depth, combined with the surface reconstruction algorithm and video compression for obtained geometry and texture maps. Texture maps have been compressed after creating Voronoi diagrams. Used video compression is specific for geometry (FFV1) and texture (H.265/HEVC). Decompressed point clouds are reconstructed using a Poisson surface reconstruction algorithm. Comparison with the original point clouds was performed using point-to-point and point-to-plane measures. Comprehensive experiments show better performance for some projection maps: cylindrical, Miller and Mercator projections. KW - 3DTK toolkit KW - map projections KW - point cloud compression KW - point-to-point measure KW - point-to-plane measure KW - Poisson surface reconstruction KW - octree Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-252231 SN - 1424-8220 VL - 22 IS - 1 ER - TY - RPRT A1 - Dworzak, Manuel A1 - Großmann, Marcel A1 - Le, Duy Thanh T1 - Federated Learning for Service Placement in Fog and Edge Computing T2 - KuVS Fachgespräch - Würzburg Workshop on Modeling, Analysis and Simulation of Next-Generation Communication Networks 2023 (WueWoWAS’23) N2 - Service orchestration requires enormous attention and is a struggle nowadays. Of course, virtualization provides a base level of abstraction for services to be deployable on a lot of infrastructures. With container virtualization, the trend to migrate applications to a micro-services level in order to be executable in Fog and Edge Computing environments increases manageability and maintenance efforts rapidly. Similarly, network virtualization adds effort to calibrate IP flows for Software-Defined Networks and eventually route it by means of Network Function Virtualization. Nevertheless, there are concepts like MAPE-K to support micro-service distribution in next-generation cloud and network environments. We want to explore, how a service distribution can be improved by adopting machine learning concepts for infrastructure or service changes. Therefore, we show how federated machine learning is integrated into a cloud-to-fog-continuum without burdening single nodes. KW - fog computing KW - SDN KW - orchestration KW - federated learning Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-322193 ER - TY - JOUR A1 - Döllinger, Nina A1 - Wienrich, Carolin A1 - Latoschik, Marc Erich T1 - Challenges and opportunities of immersive technologies for mindfulness meditation: a systematic review JF - Frontiers in Virtual Reality N2 - Mindfulness is considered an important factor of an individual's subjective well-being. Consequently, Human-Computer Interaction (HCI) has investigated approaches that strengthen mindfulness, i.e., by inventing multimedia technologies to support mindfulness meditation. These approaches often use smartphones, tablets, or consumer-grade desktop systems to allow everyday usage in users' private lives or in the scope of organized therapies. Virtual, Augmented, and Mixed Reality (VR, AR, MR; in short: XR) significantly extend the design space for such approaches. XR covers a wide range of potential sensory stimulation, perceptive and cognitive manipulations, content presentation, interaction, and agency. These facilities are linked to typical XR-specific perceptions that are conceptually closely related to mindfulness research, such as (virtual) presence and (virtual) embodiment. However, a successful exploitation of XR that strengthens mindfulness requires a systematic analysis of the potential interrelation and influencing mechanisms between XR technology, its properties, factors, and phenomena and existing models and theories of the construct of mindfulness. This article reports such a systematic analysis of XR-related research from HCI and life sciences to determine the extent to which existing research frameworks on HCI and mindfulness can be applied to XR technologies, the potential of XR technologies to support mindfulness, and open research gaps. Fifty papers of ACM Digital Library and National Institutes of Health's National Library of Medicine (PubMed) with and without empirical efficacy evaluation were included in our analysis. The results reveal that at the current time, empirical research on XR-based mindfulness support mainly focuses on therapy and therapeutic outcomes. Furthermore, most of the currently investigated XR-supported mindfulness interactions are limited to vocally guided meditations within nature-inspired virtual environments. While an analysis of empirical research on those systems did not reveal differences in mindfulness compared to non-mediated mindfulness practices, various design proposals illustrate that XR has the potential to provide interactive and body-based innovations for mindfulness practice. We propose a structured approach for future work to specify and further explore the potential of XR as mindfulness-support. The resulting framework provides design guidelines for XR-based mindfulness support based on the elements and psychological mechanisms of XR interactions. KW - virtual reality KW - augmented reality KW - mindfulness KW - XR KW - meditation Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-259047 VL - 2 ER - TY - THES A1 - Eichelberger, Holger T1 - Aesthetics and automatic layout of UML class diagrams T1 - Ästhetik und automatisches Layout von UML Klassendiagrammen N2 - In the last years, visual methods have been introduced in industrial software production and teaching of software engineering. In particular, the international standardization of a graphical software engineering language, the Unified Modeling Language (UML) was a reason for this tendency. Unfortunately, various problems exist in concrete realizations of tools, e.g. due to a missing compliance to the standard. One problem is the automatic layout, which is required for a consistent automatic software design. The thesis derives reasons and criteria for an automatic layout method, which produces drawings of UML class diagrams according to the UML specification and issues of human computer interaction, e.g. readability. A unique set of aesthetic criteria is combined from four different disciplines involved in this topic. Based on these aethetic rules, a hierarchical layout algorithm is developed, analyzed, measured by specialized measuring techniques and compared to related work. Then, the realization of the algorithm as a Java framework is given as an architectural description. Finally, adaptions to anticipated future changes of the UML, improvements of the framework and example drawings of the implementation are given. N2 - Visuelle Techniken im Software-Entwurf haben in den letzten Jahre Einzug in Industrie und Lehre gehalten. Begünstigt wurde dies durch die Unified Modeling Language (UML), eine international standardisierte, graphische Entwurfssprache. Dennoch klaffen weite Lücken bei der Umsetzung in konkrete Tools, teils an der Realisierung des Standards, insbesondere aber auch beim automatischen Layout, das für konsistenten (teil-)automatisierten Softwareentwurf unerlässlich ist. Die Arbeit stellt zunächst Gründe und Kriterien für ein standardkonformes, menschenlesbares automatisches Layout von UML Klassendiagrammen zusammen. Ästhetische Kriterien werden aus vier unterschiedlichen Fachdisziplinen destilliert und kombiniert. Basierend auf diesen Kriterien wird danach ein hierarchischer Layoutalgorithmus entwickelt, analysiert, mit speziellen Messverfahren vermessen und mit Konkurrenzalgorithmen verglichen. Im Anschluss daran wird die Realisierung des Algorithmus als Java-Framework im Rahmen einer Architekturbeschreibung diskutiert. Anpassungen an zukünftige Entwicklungen der UML, Weiterentwicklungen des Frameworks und Beispieldiagramme, die von der Implementierung generiert wurden, runden die Arbeit ab. KW - URL KW - Klassendiagramm KW - automatisches Layout KW - UML Klassendiagramm KW - semantische Ästhetik KW - Zeichnen von Graphen KW - computergestützte Softwaretechnik KW - automatic Layout KW - UML class diagram KW - semantical aesthetic KW - graph drawing KW - CASE Y1 - 2005 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-14831 ER - TY - RPRT A1 - Elsayed, Karim A1 - Rizk, Amr T1 - Response Times in Time-to-Live Caching Hierarchies under Random Network Delays T2 - Würzburg Workshop on Next-Generation Communication Networks (WueWoWas'22) N2 - Time-to-Live (TTL) caches decouple the occupancy of objects in cache through object-specific validity timers. Stateof- the art techniques provide exact methods for the calculation of object-specific hit probabilities given entire cache hierarchies with random inter-cache network delays. The system hit probability is a provider-centric metric as it relates to the origin offload, i.e., the decrease in the number of requests that are served by the content origin server. In this paper we consider a user-centric metric, i.e., the response time, which is shown to be structurally different from the system hit probability. Equipped with the state-of-theart exact modeling technique using Markov-arrival processes we derive expressions for the expected object response time and pave a way for its optimization under network delays. KW - Datennetz KW - TTL Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-280843 ER -