004 Datenverarbeitung; Informatik
Refine
Has Fulltext
- yes (75)
Is part of the Bibliography
- yes (75)
Year of publication
Document Type
- Doctoral Thesis (75) (remove)
Keywords
- Leistungsbewertung (13)
- Robotik (8)
- Mobiler Roboter (7)
- Autonomer Roboter (6)
- Komplexitätstheorie (5)
- Optimierung (5)
- Simulation (5)
- Theoretische Informatik (5)
- Modellierung (4)
- Netzwerk (4)
- Optimization (4)
- Overlay-Netz (4)
- Routing (4)
- Verteiltes System (4)
- Algorithmus (3)
- Approximationsalgorithmus (3)
- Computer Vision (3)
- Computersimulation (3)
- Dienstgüte (3)
- Drahtloses Sensorsystem (3)
- Graph (3)
- Graphenzeichnen (3)
- Komplexität (3)
- Lokalisation (3)
- Mensch-Maschine-Schnittstelle (3)
- Netzwerkmanagement (3)
- Peer-to-Peer-Netz (3)
- Performance Evaluation (3)
- graph drawing (3)
- Algorithmische Geometrie (2)
- Ausfallsicheres System (2)
- Ausfallsicherheit (2)
- Benutzerschnittstelle (2)
- Dot-Depth Problem (2)
- Drahtloses lokales Netz (2)
- Effizienter Algorithmus (2)
- Entscheidbarkeit (2)
- Fernwartung (2)
- Future Internet (2)
- Human-Robot-Interaction (2)
- IEEE 802.11 (2)
- Kleinsatellit (2)
- Kreuzung (2)
- Localization (2)
- Machine Learning (2)
- Maschinelles Lernen (2)
- Maschinelles Sehen (2)
- Mehragentensystem (2)
- Mensch-Maschine-System (2)
- Mensch-Roboter-Interaktion (2)
- Mixed Reality (2)
- PROLOG <Programmiersprache> (2)
- Punktwolke (2)
- QoE (2)
- Quality of Experience (2)
- Rechnernetz (2)
- Resilience (2)
- Resource Management (2)
- Ressourcenmanagement (2)
- Robotics (2)
- Satellit (2)
- Situation Awareness (2)
- Software Defined Networking (2)
- Teleoperation (2)
- Theoretical Computer Science (2)
- User Interface (2)
- Verbotsmuster (2)
- approximation algorithm (2)
- decidability (2)
- dot-depth problem (2)
- endliche Automaten (2)
- finite automata (2)
- forbidden patterns (2)
- knowledge representation (2)
- mobile robots (2)
- regular languages (2)
- reguläre Sprachen (2)
- simulation (2)
- 3D Pointcloud (1)
- 3D Punktwolke (1)
- 3D Reconstruction (1)
- 3D Sensor (1)
- 3D Vision (1)
- 3D point cloud (1)
- 3D thermal mapping (1)
- 3D-Rekonstruktion (1)
- 4G Networks (1)
- 6DOF Pose Estimation (1)
- Abhängigskeitsgraph (1)
- Ablaufplanung (1)
- Admission Control (1)
- Agent <Informatik> (1)
- Agent <Künstliche Intelligenz> (1)
- Agent-based Simulation (1)
- Agentbased System (1)
- Agenten-basierte Simulation (1)
- Angewandte Informatik (1)
- Anwendung (1)
- Approximation (1)
- Arterie (1)
- Artery (1)
- Automat <Automatentheorie> (1)
- Automata Theory (1)
- Automatentheorie (1)
- Autonomer Agent (1)
- Autonomie (1)
- Autonomous Robot (1)
- Autonomous multi-vehicle systems (1)
- Backbone-Netz (1)
- Background Knowledge (1)
- Benutzerinteraktion (1)
- Berechenbarkeit (1)
- Berechnungskomplexität (1)
- Bernoulli stochastics (1)
- Bernoulli-Raum (1)
- Bernoullische Stochastik (1)
- Bernoullispace (1)
- Betriebssystem (1)
- Bewegungsablauf (1)
- Bewegungskompensation (1)
- Bewegungskoordination (1)
- Bewegungsplanung (1)
- Bildverarbeitung (1)
- Bit Parallelität (1)
- BitTorrent (1)
- Bodenstation (1)
- Boolean Grammar (1)
- Boolean equivalence (1)
- Boolean functions (1)
- Boolean hierarchy (1)
- Boolean isomorphism (1)
- Boolesche Funktionen (1)
- Boolesche Grammatik (1)
- Boolesche Hierarchie (1)
- CASE (1)
- Calibration (1)
- Call Graph (1)
- Chord (1)
- Clones (1)
- Cloud Gaming (1)
- Communication Networks (1)
- Complexity Theory (1)
- Compression (1)
- Computational Geometry (1)
- Computational complexity (1)
- Computerunterstütztes Lernen (1)
- Content Distribution (1)
- DHT (1)
- Data Mining (1)
- Databases (1)
- Datenbanken (1)
- Datenbasis (1)
- Deep Georeferencing (1)
- Deep Learning (1)
- Dependency Graph (1)
- Design (1)
- Dezentrale Regelung (1)
- Diagnosesystem (1)
- Dichotomy (1)
- Diskrete Simulation (1)
- Distributed Space Systems (1)
- Domänenspezifische Sprache (1)
- Dot-Depth-Hierarchie (1)
- Drahtloses vermaschtes Netz (1)
- Dreidimensionale Rekonstruktion (1)
- Dynamic Environments (1)
- Dynamic Memory Management (1)
- Dynamische Speicherverwaltung (1)
- Echtzeitsystem (1)
- Echzeit (1)
- Edge-based Intelligence (1)
- Eingebettetes System (1)
- Elasticity tensor (1)
- Elastizitätstensor (1)
- Embedded Systems (1)
- Endpoint Mobility (1)
- Energieeffizienz (1)
- Energy efficiency (1)
- Entscheidungsfindung (1)
- Erfüllbarkeitsproblem (1)
- Erweiterte Realität (1)
- Euclidean plane (1)
- Euklidische Ebene (1)
- Expert System (1)
- Expertensystem (1)
- Fahrsimulation (1)
- Fahrsimulator (1)
- Fairness (1)
- Feature Based Registration (1)
- Feature-Matching (1)
- Fehlertoleranz (1)
- Feldprogrammierbare Architekturen (1)
- Fernsteuerung (1)
- Field programmable gate array (1)
- Field-programmable Gate Arrays (1)
- Formale Sprache (1)
- Formation (1)
- Formationsbewegung (1)
- Forschung (1)
- Funkressourcenverwaltung (1)
- Gastroenterologische Endoskopie (1)
- Gay-Array-Bauelement (1)
- Generalisierung <Kartografie> (1)
- Generation Problem (1)
- Generierungsproblem (1)
- Genetic Optimization (1)
- Genetische Optimierung (1)
- Georeferenzierung (1)
- Gllobal self-localisation (1)
- Globale Selbstlokalisation (1)
- Ground Station Networks (1)
- H.264 SVC (1)
- H.264/SVC (1)
- HSPA (1)
- Halbordnungen (1)
- Hardware (1)
- Herzkatheter (1)
- Herzkathetereingriff (1)
- Hierarchische Simulation (1)
- Hintergrundwissen (1)
- Historical Maps (1)
- Historische Karte (1)
- Historische Landkarten (1)
- Hospital (1)
- IEEE 802.11e (1)
- IEEE 802.15.4 (1)
- IP (1)
- Implementierung <Informatik> (1)
- Industrial internet (1)
- Industrie 4.0 (1)
- Inferenz <Künstliche Intelligenz> (1)
- Information Extraction (1)
- Information Retrieval (1)
- Information-Retrieval-System (1)
- Interaktion (1)
- Internet Protokoll (1)
- Invertierte Liste (1)
- Isomorphie (1)
- Itinerare (1)
- Itineraries (1)
- Java <Programmiersprache> (1)
- Java Message Service (1)
- Kademlia (1)
- Kanalzugriff (1)
- Karte (1)
- Kartierung (1)
- Klassendiagramm (1)
- Knowledge Discovery (1)
- Knowledge-based Systems Engineering (1)
- Kombinatorik (1)
- Kommunikation (1)
- Kommunikationsnetze (1)
- Komplexitätsklasse (1)
- Komplexitätsklasse NP (1)
- Konvexe Zeichnungen (1)
- Konzeptsuche (1)
- Kooperierende mobile Roboter (1)
- Krankenhaus (1)
- Kreuzungsminimierung (1)
- Kurve (1)
- Künstliche Intelligenz (1)
- Landkartenbeschriftung (1)
- Landnutzungskartierung (1)
- Laser scanning (1)
- Learning (1)
- Lehre (1)
- Lernen (1)
- Lidar (1)
- Link rate adaptation (1)
- Linkratenanpassung (1)
- Logic Programming (1)
- Logische Programmierung (1)
- MAC (1)
- Mathematische Modellierung (1)
- Mathematisches Modell (1)
- Medical Image Analysis (1)
- Medium <Physik> (1)
- Medizin (1)
- Mehrebenensimulation (1)
- Mehrfahrzeugsysteme (1)
- Mehrkriterielle Optimierung (1)
- Mehrpfadübertragung (1)
- Mehrschichtnetze (1)
- Mehrschichtsystem (1)
- Mesh Networks (1)
- Mesh Netze (1)
- Middleware (1)
- Miniaturisierung (1)
- Minimally invasive vascular intervention (1)
- Missionsbetrieb (1)
- Mobile Roboter (1)
- Mobiles Internet (1)
- Mobilfunk (1)
- Modellbasierte Diagnose (1)
- Modellierungstechniken (1)
- Modelling (1)
- Modularität (1)
- Motion Planning (1)
- Multi-Agent-Simulation (1)
- Multi-Layer (1)
- Multi-Network Service (1)
- Multi-Netzwerk Dienste (1)
- Multi-Paradigm Programming (1)
- Multi-Paradigm Programming Framework (1)
- Multi-agent system (1)
- Multiagentensimulation (1)
- Multiagentensystem (1)
- Multimedia (1)
- Multipath Transmission (1)
- Mustererkennung (1)
- NP (1)
- NP-Vollständigkeit (1)
- NP-complete sets (1)
- NP-hardness (1)
- NP-hartes Problem (1)
- NP-schweres Problem (1)
- Network Management (1)
- Network Virtualization (1)
- Netzplantechnik (1)
- Netzplanung (1)
- Netzwerkplanung (1)
- Netzwerkvirtualisierung (1)
- Next Generation Networks (1)
- Nichtholonome Fahrzeuge (1)
- Nichtlineare Regelung (1)
- Object Detection (1)
- Object-Oriented Programming (1)
- Objektorientierte Programmierung (1)
- Operator (1)
- Optimale Kontrolle (1)
- Optimierungsproblem (1)
- Overlay (1)
- Overlay Netzwerke (1)
- Overlay networks (1)
- Overlays (1)
- Panorama Images (1)
- Parameterkalibrierung (1)
- Partition <Mengenlehre> (1)
- Partitionen (1)
- Path Computation Element (1)
- Pattern Recognition (1)
- Peer-to-Peer (1)
- Performance Analysis (1)
- Performance Modeling (1)
- Pfadberechnungselement (1)
- Picosatellite (1)
- Planare Graphen (1)
- Planausführung (1)
- Planung (1)
- Planungssystem (1)
- Polyeder (1)
- Polypektomie (1)
- Post's Classes (1)
- Postsche Klassen (1)
- Prediction (1)
- Process Optimization (1)
- Programmierbare logische Anordnung (1)
- Prozessoptimierung (1)
- Publish-Subscribe-System (1)
- QoS (1)
- Quality of Experience QoE (1)
- Quality of Service (1)
- Quality-of-Experience (1)
- Quality-of-Service (QoS) (1)
- Quantor (1)
- Raumdaten (1)
- Real-Time Operating Systems (1)
- Real-time (1)
- Refactoring (1)
- Regelbasiertes System (1)
- Regelung (1)
- Registration (1)
- Registrierung (1)
- Reguläre Sprache (1)
- Rendezvous (1)
- Ressourcen Management (1)
- Ressourcenallokation (1)
- Rettungsroboter (1)
- Robot (1)
- Roboter (1)
- Rule-based Systems (1)
- Scheduling (1)
- Search-and-Rescue (1)
- Selbstkalibrierung (1)
- Self-calibration (1)
- Semantic Web (1)
- Semantics (1)
- Semantik (1)
- Sensor (1)
- Service Mobility (1)
- Sichtbarkeit (1)
- Similarity Measure (1)
- Simulator (1)
- Situationsbewusstsein (1)
- Skype (1)
- Small Satellites (1)
- Smart User Interaction (1)
- Social Web (1)
- Software (1)
- Software Engineering (1)
- Source Code Visualization (1)
- Soziale Software (1)
- Standortproblem (1)
- Sternfreie Sprache (1)
- Steuerung (1)
- Stiffness (1)
- Stochastik (1)
- Stochastikon (1)
- Strahlentherapie (1)
- Straubing-Th´erien-Hierarchie (1)
- Straßennetzwerk (1)
- Straßenverkehr (1)
- Strukturelle Komplexität (1)
- Subgroup Mining (1)
- Subgruppenentdeckung (1)
- Suchverfahren (1)
- System (1)
- Szenariogenerierung (1)
- Teaching (1)
- Telematik (1)
- Theoretical computer science (1)
- Thermografie (1)
- Trainingssystem (1)
- Travelling-salesman-Problem (1)
- Tumor motion (1)
- Tumorbewegung (1)
- U-Bahnlinienplan (1)
- UI and Interaction Design (1)
- UML Klassendiagramm (1)
- UML class diagram (1)
- UMTS (1)
- URL (1)
- Underwater Mapping (1)
- Underwater Scanning (1)
- Unstetige Regelung (1)
- Usability (1)
- User Behavior (1)
- User Participation (1)
- Verbotenes Muster (1)
- Verbände (1)
- Verkehrslenkung (1)
- Verteilung von Inhalten (1)
- Video Quality Monitoring (1)
- Video Streaming (1)
- Videoübertragung (1)
- Virtuelles Netzwerk (1)
- Visibility (1)
- Visual Tracking (1)
- Visualisierung (1)
- Visualization (1)
- Voice-over-IP (VoIP) (1)
- Volltextsuche (1)
- Vorhersage (1)
- WLAN (1)
- Warteschlangentheorie (1)
- Werkstattdiagnose (1)
- Winkel (1)
- Wire relaxation (1)
- Wireless LAN (1)
- Wireless Sensor/Actuator Systems (1)
- Wissensbasiertes System (1)
- Wissensendeckung (1)
- Wissensrepräsentation (1)
- Worterweiterungen (1)
- Zeichnen von Graphen (1)
- Zeitdiskretes System (1)
- Zugangskontrolle (1)
- Zählprobleme (1)
- abgeschlossene Klassen (1)
- administrative boundary (1)
- admission control (1)
- aftermarket diagnostic (1)
- agile Prozesse (1)
- agile processes (1)
- angular schematization (1)
- approximation algorithms (1)
- automatic Layout (1)
- automatisches Layout (1)
- bit-parallel (1)
- boundary labeling (1)
- building (1)
- car-like robots (1)
- competitive location (1)
- complexity (1)
- computational complexity (1)
- computergestützte Softwaretechnik (1)
- concept search (1)
- constrained forest (1)
- contact representation (1)
- counting problems (1)
- crossing minimization (1)
- curves (1)
- d3web.Train (1)
- data structure (1)
- database (1)
- decission finding (1)
- definite clause grammars (1)
- dial a ride (1)
- discrete-time analysis (1)
- driving simulation (1)
- dynamische Umgebungen (1)
- edge labeled graphs (1)
- educational tool (1)
- efficient algorithm (1)
- fast reroute (1)
- feature-matching (1)
- field-programmable architectures (1)
- field-programmable gate arrays (1)
- formation driving (1)
- full-text search (1)
- graph (1)
- graph decomposition (1)
- graphs (1)
- hardness (1)
- hybrid Diagnostic (1)
- hybride Diagnose (1)
- independent crossing (1)
- intelligente Applikationen (1)
- internet protocol (1)
- labeling (1)
- land-cover area (1)
- lattices (1)
- load balancing (1)
- logic programming (1)
- metro map (1)
- mission operation (1)
- mobile networks (1)
- model predictive control (1)
- model-base diagnosis (1)
- modeling techniques (1)
- monotone drawing (1)
- morphing (1)
- multi-vehicle formations (1)
- multi-vehicle rendezvous (1)
- n-Gramm (1)
- n-gram (1)
- network (1)
- network design (1)
- network planning (1)
- network softwarization (1)
- network upgrade (1)
- networked robotics (1)
- networks (1)
- nonholonomic vehicles (1)
- optimization (1)
- overprovisioning (1)
- partitions (1)
- performance evaluation (1)
- plan execution (1)
- posets (1)
- q-Gramm (1)
- q-gram (1)
- radio resource management (1)
- receding horizon control (1)
- reload cost (1)
- remote control (1)
- resilience (1)
- right angle crossing (1)
- road network (1)
- robotics (1)
- routing (1)
- scenario creation (1)
- scheduling (1)
- semantic web (1)
- semantical aesthetic (1)
- semantische Ästhetik (1)
- sensor (1)
- simultaneous embedding (1)
- skalierbare Diagnose (1)
- slam (1)
- smooth orthogonal drawing (1)
- snow shoveling (1)
- spanning tree (1)
- stochastic thinking (1)
- stochastisches Denken (1)
- structural complexity (1)
- system (1)
- telematics (1)
- training systems (1)
- trajectory planning (1)
- tree (1)
- v (1)
- vernetzte Roboter (1)
- vom Nutzer erfahrene Dienstgüte QoE (1)
- voting location (1)
- word clouds (1)
- word extensions (1)
- zooming (1)
- zukünftige Kommunikationsnetze (1)
- zukünftiges Internet (1)
- Ähnlichkeitsmaß (1)
Institute
- Institut für Informatik (75) (remove)
Schriftenreihe
Sonstige beteiligte Institutionen
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.
Deep learning enables enormous progress in many computer vision-related tasks. Artificial Intel- ligence (AI) steadily yields new state-of-the-art results in the field of detection and classification. Thereby AI performance equals or exceeds human performance. Those achievements impacted many domains, including medical applications.
One particular field of medical applications is gastroenterology. In gastroenterology, machine learning algorithms are used to assist examiners during interventions. One of the most critical concerns for gastroenterologists is the development of Colorectal Cancer (CRC), which is one of the leading causes of cancer-related deaths worldwide. Detecting polyps in screening colonoscopies is the essential procedure to prevent CRC. Thereby, the gastroenterologist uses an endoscope to screen the whole colon to find polyps during a colonoscopy. Polyps are mucosal growths that can vary in severity.
This thesis supports gastroenterologists in their examinations with automated detection and clas- sification systems for polyps. The main contribution is a real-time polyp detection system. This system is ready to be installed in any gastroenterology practice worldwide using open-source soft- ware. The system achieves state-of-the-art detection results and is currently evaluated in a clinical trial in four different centers in Germany.
The thesis presents two additional key contributions: One is a polyp detection system with ex- tended vision tested in an animal trial. Polyps often hide behind folds or in uninvestigated areas. Therefore, the polyp detection system with extended vision uses an endoscope assisted by two additional cameras to see behind those folds. If a polyp is detected, the endoscopist receives a vi- sual signal. While the detection system handles the additional two camera inputs, the endoscopist focuses on the main camera as usual.
The second one are two polyp classification models, one for the classification based on shape (Paris) and the other on surface and texture (NBI International Colorectal Endoscopic (NICE) classification). Both classifications help the endoscopist with the treatment of and the decisions about the detected polyp.
The key algorithms of the thesis achieve state-of-the-art performance. Outstandingly, the polyp detection system tested on a highly demanding video data set shows an F1 score of 90.25 % while working in real-time. The results exceed all real-time systems in the literature. Furthermore, the first preliminary results of the clinical trial of the polyp detection system suggest a high Adenoma Detection Rate (ADR). In the preliminary study, all polyps were detected by the polyp detection system, and the system achieved a high usability score of 96.3 (max 100). The Paris classification model achieved an F1 score of 89.35 % which is state-of-the-art. The NICE classification model achieved an F1 score of 81.13 %.
Furthermore, a large data set for polyp detection and classification was created during this thesis. Therefore a fast and robust annotation system called Fast Colonoscopy Annotation Tool (FastCAT) was developed. The system simplifies the annotation process for gastroenterologists. Thereby the
i
gastroenterologists only annotate key parts of the endoscopic video. Afterward, those video parts are pre-labeled by a polyp detection AI to speed up the process. After the AI has pre-labeled the frames, non-experts correct and finish the annotation. This annotation process is fast and ensures high quality. FastCAT reduces the overall workload of the gastroenterologist on average by a factor of 20 compared to an open-source state-of-art annotation tool.
The landscape of today’s programming languages is manifold. With the diversity of applications, the difficulty of adequately addressing and specifying the used programs increases. This often leads to newly designed and implemented domain-specific languages. They enable domain experts to express knowledge in their preferred format, resulting in more readable and concise programs. Due to its flexible and declarative syntax without reserved keywords, the logic programming language Prolog is particularly suitable for defining and embedding domain-specific languages.
This thesis addresses the questions and challenges that arise when integrating domain-specific languages into Prolog. We compare the two approaches to define them either externally or internally, and provide assisting tools for each. The grammar of a formal language is usually defined in the extended Backus–Naur form. In this work, we handle this formalism as a domain-specific language in Prolog, and define term expansions that allow to translate it into equivalent definite clause grammars. We present the package library(dcg4pt) for SWI-Prolog, which enriches them by an additional argument to automatically process the term’s corresponding parse tree. To simplify the work with definite clause grammars, we visualise their application by a web-based tracer.
The external integration of domain-specific languages requires the programmer to keep the grammar, parser, and interpreter in sync. In many cases, domain-specific languages can instead be directly embedded into Prolog by providing appropriate operator definitions. In addition, we propose syntactic extensions for Prolog to expand its expressiveness, for instance to state logic formulas with their connectives verbatim. This allows to use all tools that were originally written for Prolog, for instance code linters and editors with syntax highlighting. We present the package library(plammar), a standard-compliant parser for Prolog source code, written in Prolog. It is able to automatically infer from example sentences the required operator definitions with their classes and precedences as well as the required Prolog language extensions. As a result, we can automatically answer the question: Is it possible to model these example sentences as valid Prolog clauses, and how?
We discuss and apply the two approaches to internal and external integrations for several domain-specific languages, namely the extended Backus–Naur form, GraphQL, XPath, and a controlled natural language to represent expert rules in if-then form. The created toolchain with library(dcg4pt) and library(plammar) yields new application opportunities for static Prolog source code analysis, which we also present.
In this doctoral thesis we cover the performance evaluation of next generation data plane architectures, comprised of complex software as well as programmable hardware components that allow fine granular configuration. In the scope of the thesis we propose mechanisms to monitor the performance of singular components and model key performance indicators of software based packet processing solutions. We present novel approaches towards network abstraction that allow the integration of heterogeneous data plane technologies into a singular network while maintaining total transparency between control and data plane. Finally, we investigate a full, complex system consisting of multiple software-based solutions and perform a detailed performance analysis. We employ simulative approaches to investigate overload control mechanisms that allow efficient operation under adversary conditions. The contributions of this work build the foundation for future research in the areas of network softwarization and network function virtualization.
Constraining graph layouts - that is, restricting the placement of vertices and the routing of edges to obey certain constraints - is common practice in graph drawing.
In this book, we discuss algorithmic results on two different restriction types:
placing vertices on the outer face and on the integer grid.
For the first type, we look into the outer k-planar and outer k-quasi-planar graphs, as well as giving a linear-time algorithm to recognize full and closed outer k-planar graphs Monadic Second-order Logic.
For the second type, we consider the problem of transferring a given planar drawing onto the integer grid while perserving the original drawings topology;
we also generalize a variant of Cauchy's rigidity theorem for orthogonal polyhedra of genus 0 to those of arbitrary genus.
Maps are the main tool to represent geographical information. Users often zoom in and out to access maps at different scales. Continuous map generalization tries to make the changes between different scales smooth, which is essential to provide users with comfortable zooming experience.
In order to achieve continuous map generalization with high quality, we optimize some important aspects of maps. In this book, we have used optimization in the generalization of land-cover areas, administrative boundaries, buildings, and coastlines. According to our experiments, continuous map generalization indeed benefits from optimization.
Making machines understand natural language is a dream of mankind that existed
since a very long time. Early attempts at programming machines to converse with
humans in a supposedly intelligent way with humans relied on phrase lists and simple
keyword matching. However, such approaches cannot provide semantically adequate
answers, as they do not consider the specific meaning of the conversation. Thus, if we
want to enable machines to actually understand language, we need to be able to access
semantically relevant background knowledge. For this, it is possible to query so-called
ontologies, which are large networks containing knowledge about real-world entities
and their semantic relations. However, creating such ontologies is a tedious task, as often
extensive expert knowledge is required. Thus, we need to find ways to automatically
construct and update ontologies that fit human intuition of semantics and semantic
relations. More specifically, we need to determine semantic entities and find relations
between them. While this is usually done on large corpora of unstructured text, previous
work has shown that we can at least facilitate the first issue of extracting entities by
considering special data such as tagging data or human navigational paths. Here, we do
not need to detect the actual semantic entities, as they are already provided because of
the way those data are collected. Thus we can mainly focus on the problem of assessing
the degree of semantic relatedness between tags or web pages. However, there exist
several issues which need to be overcome, if we want to approximate human intuition of
semantic relatedness. For this, it is necessary to represent words and concepts in a way
that allows easy and highly precise semantic characterization. This also largely depends
on the quality of data from which these representations are constructed.
In this thesis, we extract semantic information from both tagging data created by users
of social tagging systems and human navigation data in different semantic-driven social
web systems. Our main goal is to construct high quality and robust vector representations
of words which can the be used to measure the relatedness of semantic concepts.
First, we show that navigation in the social media systems Wikipedia and BibSonomy is
driven by a semantic component. After this, we discuss and extend methods to model
the semantic information in tagging data as low-dimensional vectors. Furthermore, we
show that tagging pragmatics influences different facets of tagging semantics. We then
investigate the usefulness of human navigational paths in several different settings on
Wikipedia and BibSonomy for measuring semantic relatedness. Finally, we propose
a metric-learning based algorithm in adapt pre-trained word embeddings to datasets
containing human judgment of semantic relatedness.
This work contributes to the field of studying semantic relatedness between words
by proposing methods to extract semantic relatedness from web navigation, learn highquality
and low-dimensional word representations from tagging data, and to learn
semantic relatedness from any kind of vector representation by exploiting human
feedback. Applications first and foremest lie in ontology learning for the Semantic Web,
but also semantic search or query expansion.
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.
Given points in the plane, connect them using minimum ink. Though the task seems simple, it turns out to be very time consuming. In fact, scientists believe that computers cannot efficiently solve it. So, do we have to resign? This book examines such NP-hard network-design problems, from connectivity problems in graphs to polygonal drawing problems on the plane. First, we observe why it is so hard to optimally solve these problems. Then, we go over to attack them anyway. We develop fast algorithms that find approximate solutions that are very close to the optimal ones. Hence, connecting points with slightly more ink is not hard.
Der Betrieb von Satelliten wird sich in Zukunft gravierend ändern. Die bisher ausgeübte konventionelle Vorgehensweise, bei der die Planung der vom Satelliten auszuführenden Aktivitäten sowie die Kontrolle hierüber ausschließlich vom Boden aus erfolgen, stößt bei heutigen Anwendungen an ihre Grenzen. Im schlimmsten Fall verhindert dieser Umstand sogar die Erschließung bisher ungenutzter Möglichkeiten. Der Gewinn eines Satelliten, sei es in Form wissenschaftlicher Daten oder der Vermarktung satellitengestützter Dienste, wird daher nicht optimal ausgeschöpft.
Die Ursache für dieses Problem lässt sich im Grunde auf eine ausschlaggebende Tatsache zurückführen: Konventionelle Satelliten können ihr Verhalten, d.h. die Folge ihrer Tätigkeiten, nicht eigenständig anpassen. Stattdessen erstellt das Bedienpersonal am Boden - vor allem die Operatoren - mit Hilfe von Planungssoftware feste Ablaufpläne, die dann in Form von Kommandosequenzen von den Bodenstationen aus an die jeweiligen Satelliten hochgeladen werden. Dort werden die Befehle lediglich überprüft, interpretiert und strikt ausgeführt. Die Abarbeitung erfolgt linear. Situationsbedingte Änderungen, wie sie vergleichsweise bei der Codeausführung von Softwareprogrammen durch Kontrollkonstrukte, zum Beispiel Schleifen und Verzweigungen, üblich sind, sind typischerweise nicht vorgesehen. Der Operator ist daher die einzige Instanz, die das Verhalten des Satelliten mittels Kommandierung, per Upload, beeinflussen kann, und auch nur dann, wenn ein direkter Funkkontakt zwischen Satellit und Bodenstation besteht. Die dadurch möglichen Reaktionszeiten des Satelliten liegen bestenfalls bei einigen Sekunden, falls er sich im Wirkungsbereich der Bodenstation befindet. Außerhalb des Kontaktfensters kann sich die Zeitschranke, gegeben durch den Orbit und die aktuelle Position des Satelliten, von einigen Minuten bis hin zu einigen Stunden erstrecken. Die Signallaufzeiten der Funkübertragung verlängern die Reaktionszeiten um weitere Sekunden im erdnahen Bereich. Im interplanetaren Raum erstrecken sich die Zeitspannen aufgrund der immensen Entfernungen sogar auf mehrere Minuten. Dadurch bedingt liegt die derzeit technologisch mögliche, bodengestützte, Reaktionszeit von Satelliten bestenfalls im Bereich von einigen Sekunden.
Diese Einschränkung stellt ein schweres Hindernis für neuartige Satellitenmissionen, bei denen insbesondere nichtdeterministische und kurzzeitige Phänomene (z.B. Blitze und Meteoreintritte in die Erdatmosphäre) Gegenstand der Beobachtungen sind, dar. Die langen Reaktionszeiten des konventionellen Satellitenbetriebs verhindern die Realisierung solcher Missionen, da die verzögerte Reaktion erst erfolgt, nachdem das zu beobachtende Ereignis bereits abgeschlossen ist.
Die vorliegende Dissertation zeigt eine Möglichkeit, das durch die langen Reaktionszeiten entstandene Problem zu lösen, auf. Im Zentrum des Lösungsansatzes steht dabei die Autonomie. Im Wesentlichen geht es dabei darum, den Satelliten mit der Fähigkeit auszustatten, sein Verhalten, d.h. die Folge seiner Tätigkeiten, eigenständig zu bestimmen bzw. zu ändern. Dadurch wird die direkte Abhängigkeit des Satelliten vom Operator bei Reaktionen aufgehoben. Im Grunde wird der Satellit in die Lage versetzt, sich selbst zu kommandieren.
Die Idee der Autonomie wurde im Rahmen der zugrunde liegenden Forschungsarbeiten umgesetzt. Das Ergebnis ist ein autonomes Planungssystem. Dabei handelt es sich um ein Softwaresystem, mit dem sich autonomes Verhalten im Satelliten realisieren lässt. Es kann an unterschiedliche Satellitenmissionen angepasst werden. Ferner deckt es verschiedene Aspekte des autonomen Satellitenbetriebs, angefangen bei der generellen Entscheidungsfindung der Tätigkeiten, über die zeitliche Ablaufplanung unter Einbeziehung von Randbedingungen (z.B. Ressourcen) bis hin zur eigentlichen Ausführung, d.h. Kommandierung, ab. Das Planungssystem kommt als Anwendung in ASAP, einer autonomen Sensorplattform, zum Einsatz. Es ist ein optisches System und dient der Detektion von kurzzeitigen Phänomenen und Ereignissen in der Erdatmosphäre.
Die Forschungsarbeiten an dem autonomen Planungssystem, an ASAP sowie an anderen zu diesen in Bezug stehenden Systemen wurden an der Professur für Raumfahrttechnik des Lehrstuhls Informatik VIII der Julius-Maximilians-Universität Würzburg durchgeführt.