004 Datenverarbeitung; Informatik
Refine
Has Fulltext
- yes (285)
Year of publication
Document Type
- Journal article (127)
- Doctoral Thesis (80)
- Working Paper (37)
- Preprint (19)
- Conference Proceeding (9)
- Jahresbericht (5)
- Master Thesis (4)
- Report (3)
- Other (1)
Language
- English (257)
- German (27)
- Multiple languages (1)
Keywords
- virtual reality (16)
- Datennetz (14)
- Leistungsbewertung (13)
- Quran (8)
- Robotik (8)
- Koran (7)
- Mobiler Roboter (7)
- Text Mining (7)
- Autonomer Roboter (6)
- Simulation (6)
- Computer Center University of Wuerzburg (5)
- Jahresbericht (5)
- Komplexitätstheorie (5)
- Maschinelles Lernen (5)
- Netzwerk (5)
- Optimierung (5)
- P4 (5)
- Theoretische Informatik (5)
- Visualisierung (5)
- annual report (5)
- artificial intelligence (5)
- machine learning (5)
- Drahtloses Sensorsystem (4)
- Modellierung (4)
- Optimization (4)
- Overlay-Netz (4)
- RZUW (4)
- Routing (4)
- SDN (4)
- Verteiltes System (4)
- XML (4)
- augmented reality (4)
- database (4)
- deep learning (4)
- human-computer interaction (4)
- Algorithmus (3)
- Approximationsalgorithmus (3)
- Bayesian classifier (3)
- Computer Vision (3)
- Computersimulation (3)
- Data Mining (3)
- Deep learning (3)
- Dienstgüte (3)
- Graph (3)
- Graphenzeichnen (3)
- IoT (3)
- Julius-Maximilians-Universität Würzburg (3)
- Komplexität (3)
- Künstliche Intelligenz (3)
- Lokalisation (3)
- Machine Learning (3)
- Mensch-Maschine-Schnittstelle (3)
- Netzwerkmanagement (3)
- Peer-to-Peer-Netz (3)
- Performance Evaluation (3)
- QoE (3)
- Quadrocopter (3)
- Quality of Experience (3)
- Rechenzentrum (3)
- Rechnernetz (3)
- Ressourcenmanagement (3)
- Robotics (3)
- Software Engineering (3)
- Softwarearchitektur (3)
- Textvergleich (3)
- Visualization (3)
- Wissensmanagement (3)
- approximation algorithm (3)
- crowdsensing (3)
- graph drawing (3)
- immersion (3)
- mHealth (3)
- neural networks (3)
- resistance (3)
- simulation (3)
- 5G (2)
- Algorithmische Geometrie (2)
- Ausfallsicheres System (2)
- Ausfallsicherheit (2)
- Base text (2)
- Benutzerschnittstelle (2)
- CSS (2)
- Cascading Style Sheets (2)
- Content Management (2)
- Crowdsourcing (2)
- Dot-Depth Problem (2)
- Drahtloses lokales Netz (2)
- Effizienter Algorithmus (2)
- Entscheidbarkeit (2)
- Entscheidungsfindung (2)
- Fernwartung (2)
- Future Internet (2)
- Gothenburg model (2)
- Human-Robot-Interaction (2)
- IEEE 802.11 (2)
- IT Security (2)
- IT-Sicherheit (2)
- Internet of Things (2)
- Kleinsatellit (2)
- Knowledge Management (2)
- Kreuzung (2)
- Localization (2)
- MP-DCCP (2)
- Maschinelles Sehen (2)
- Mehragentensystem (2)
- Mensch-Maschine-System (2)
- Mensch-Roboter-Interaktion (2)
- Meta-model (2)
- Mixed Reality (2)
- Multimedia (2)
- Mustererkennung (2)
- NP-hardness (2)
- PROLOG <Programmiersprache> (2)
- Programmierbare logische Anordnung (2)
- Punktwolke (2)
- Quadrotor (2)
- Resilience (2)
- Resource Management (2)
- Satellit (2)
- Situation Awareness (2)
- Software Defined Networking (2)
- Teleoperation (2)
- Text mining (2)
- Textual alterations weighting system (2)
- Textual document collation (2)
- Theoretical Computer Science (2)
- User Interface (2)
- Verbotsmuster (2)
- Wissensrepräsentation (2)
- Wrapper <Programmierung> (2)
- XR (2)
- automation (2)
- connected mobility applications (2)
- cosmology (2)
- crossing minimization (2)
- decidability (2)
- design (2)
- dot-depth problem (2)
- education (2)
- educational tool (2)
- endliche Automaten (2)
- endoscopy (2)
- engineering (2)
- evolution (2)
- exposure (2)
- finite automata (2)
- fog computing (2)
- forbidden patterns (2)
- framework (2)
- fully convolutional neural networks (2)
- games (2)
- gastroenterology (2)
- genetics (2)
- historical document analysis (2)
- immersive technologies (2)
- knowledge representation (2)
- measurements (2)
- metabolic modeling (2)
- mobile networks (2)
- mobile robots (2)
- multipath (2)
- multipath scheduling (2)
- natural variation (2)
- navigation (2)
- network calculus (2)
- networks (2)
- ontology (2)
- perception (2)
- prediction (2)
- regular languages (2)
- reguläre Sprachen (2)
- satellite communication (2)
- scalability (2)
- scheduling (2)
- segmentation (2)
- self-aware computing (2)
- sensor (2)
- smart speaker (2)
- spatial presence (2)
- tinnitus (2)
- virtual agent (2)
- virtual environments (2)
- 26S RDNA Data (1)
- 3D Laser Scanning (1)
- 3D Pointcloud (1)
- 3D Punktwolke (1)
- 3D Reconstruction (1)
- 3D Sensor (1)
- 3D Vision (1)
- 3D collation (1)
- 3D fluoroscopy (1)
- 3D point cloud (1)
- 3D thermal mapping (1)
- 3D viewer (1)
- 3D-Rekonstruktion (1)
- 3D-reconstruction methods (1)
- 3DTK toolkit (1)
- 4D-GIS (1)
- 4G Networks (1)
- 5G core network (1)
- 5G-ATSSS (1)
- 5GC (1)
- 6DOF Pose Estimation (1)
- 6G (1)
- ACKR4 (1)
- AI (1)
- AKT (1)
- ATSSSS (1)
- AVA (1)
- Abhängigskeitsgraph (1)
- Ablaufplanung (1)
- Accessibility (1)
- Add-on-Miss (1)
- Admission Control (1)
- Agent <Informatik> (1)
- Agent <Künstliche Intelligenz> (1)
- Agent-based Simulation (1)
- Agentbased System (1)
- Agenten-basierte Simulation (1)
- Analysis (1)
- Anforderungsmanagement (1)
- Angewandte Informatik (1)
- Annotation (1)
- Anwendung (1)
- Anwendungsfall (1)
- Approximation (1)
- Arctic (1)
- Arterie (1)
- Artery (1)
- Aufsatzsammlung (1)
- Aufwandsanalyse (1)
- Automat <Automatentheorie> (1)
- Automata Theory (1)
- Automatentheorie (1)
- Automatisierte Prüfungskorrektur (1)
- Autonomer Agent (1)
- Autonomie (1)
- Autonomous Robot (1)
- Autonomous UAV (1)
- Autonomous multi-vehicle systems (1)
- Autorotation (1)
- BPM (1)
- BPMN (1)
- Backbone-Netz (1)
- Background Knowledge (1)
- Balloon (1)
- Banks Islands (1)
- Barcodes (1)
- Bayes-Klassifikator (1)
- Benutzererlebnis (1)
- Benutzerforschung (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)
- Biological Networks (1)
- Biology (1)
- Bit Parallelität (1)
- BitTorrent (1)
- Bodenstation (1)
- Boolean Grammar (1)
- Boolean equivalence (1)
- Boolean function (1)
- Boolean functions (1)
- Boolean hierarchy (1)
- Boolean isomorphism (1)
- Boolean tree (1)
- Boolesche Funktionen (1)
- Boolesche Grammatik (1)
- Boolesche Hierarchie (1)
- Brüder Grimm Privatbibliothek (1)
- Business Intelligence (1)
- CASE (1)
- CD4+T cells (1)
- CD8+T cells (1)
- CD95 (1)
- CETCH cycle (1)
- CHI Conference (1)
- CLIP (1)
- CO2-sequestration (1)
- COVID-19 (1)
- Caenorhabditis elegans (1)
- Calibration (1)
- Call Graph (1)
- Causes of revelation (1)
- Chapters arrangement (1)
- Charged aerosol detector (CAD) (1)
- Chord (1)
- Chronology of revelation (1)
- Clones (1)
- Cloud Gaming (1)
- Clustering (1)
- Colonial volvocales chlorophyta (1)
- Communication Networks (1)
- Complex Systems (1)
- Complexity Theory (1)
- Compression (1)
- Computational Geometry (1)
- Computational complexity (1)
- Computer software (1)
- Computerspiel (1)
- Computerunterstütztes Lernen (1)
- Computervirus (1)
- Containerization (1)
- Content Distribution (1)
- Convolutional Neural Network (1)
- Cost Analysis (1)
- Crowdsensing (1)
- CubeSat (1)
- DHT (1)
- DNA (1)
- DNA storage (1)
- Daedalus-Projekt (1)
- Dasycladales chlorophyta (1)
- Databases (1)
- Datenbanken (1)
- Datenbasis (1)
- Datenkommunikationsnetz (1)
- Datenübertragung ; Datensicherung ; Informationstechnik ; Internet ; Computersicherheit (1)
- Deep Georeferencing (1)
- Deep Learning (1)
- Dependency Graph (1)
- Design (1)
- Design and Development (1)
- Dezentrale Regelung (1)
- Diagnosesystem (1)
- Dichotomy (1)
- Dienstleistungen (1)
- Digital Elevation Model (1)
- Digitalisierung (1)
- Dijkstra’s algorithm (1)
- Diskrete Simulation (1)
- Distributed Space Systems (1)
- Domänenspezifische Sprache (1)
- Dot-Depth-Hierarchie (1)
- Drahtloses vermaschtes Netz (1)
- Dreidimensionale Rekonstruktion (1)
- Dreieck (1)
- Dynamic Environments (1)
- Dynamic Memory Management (1)
- Dynamische Speicherverwaltung (1)
- E8 symmetry (1)
- EEG (1)
- EEG frequency band analysis (1)
- EEG preprocessing (1)
- EEG processing (1)
- EPM (1)
- Echtzeitsystem (1)
- Echzeit (1)
- Edge-MEC-Cloud (1)
- Edge-based Intelligence (1)
- Educational Measurement (I2.399) (1)
- Eingebettetes System (1)
- Elasticity tensor (1)
- Elastizitätstensor (1)
- Embedded Systems (1)
- Emotion inference (1)
- Emotionserkennung (1)
- Emotionsinterpretation (1)
- Endnutzer (1)
- Endpoint Mobility (1)
- Energieeffizienz (1)
- Energy efficiency (1)
- Entscheidungsträger (1)
- Erfüllbarkeitsproblem (1)
- Erkennung handschriftlicher Artefakte (1)
- Erweiterte Realität (1)
- Ethik (1)
- Euclidean plane (1)
- Euklidische Ebene (1)
- Expert System (1)
- Expertensystem (1)
- FIFO caching strategies (1)
- FLIMbee (1)
- Fachgespräch (1)
- Fahrsimulation (1)
- Fahrsimulator (1)
- Fairness (1)
- Fallstudie (1)
- Fatty acids (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)
- Firewall (1)
- Flugkörper (1)
- Forces (1)
- Formale Sprache (1)
- Formation (1)
- Formation Flight (1)
- Formationsbewegung (1)
- Formmessung (1)
- Forschung (1)
- Fragmentation (1)
- Fragmentierung (1)
- Frames (1)
- Frühdruck (1)
- Funkressourcenverwaltung (1)
- GNSS/INS integrated navigation (1)
- Gastroenterologische Endoskopie (1)
- Gay-Array-Bauelement (1)
- Gefühl (1)
- Generalisierung <Kartografie> (1)
- Generation Problem (1)
- Generierungsproblem (1)
- Genetic Optimization (1)
- Genetische Optimierung (1)
- Georeferenzierung (1)
- Gllobal self-localisation (1)
- Globale Selbstlokalisation (1)
- Gothenburg Modell (1)
- Gothenburg model of collation process (1)
- Gradient boosted trees (GBT) (1)
- Graphentheorie (1)
- Grimm brothers personal library (1)
- Ground Station Networks (1)
- H.264 SVC (1)
- H.264/SVC (1)
- HGPS (1)
- HHblits (1)
- HMD (Head-Mounted Display) (1)
- HSPA (1)
- HTML (1)
- HTTP adaptive video streaming (1)
- Halbordnungen (1)
- Handschrift (1)
- Hardware (1)
- Herzkatheter (1)
- Herzkathetereingriff (1)
- Hierarchische Simulation (1)
- High-performance liquid chromatography (HPLC) (1)
- Hintergrundwissen (1)
- Historical Maps (1)
- Historische Karte (1)
- Historische Landkarten (1)
- Hittitology (1)
- Hochschulnetz (1)
- Hospital (1)
- Human-centered computing / Access (1)
- Human-centered computing / Human computer interaction (HCI) / Interaction paradigms / Mixed / augmented reality (1)
- Human-centered computing / Human computer interaction (HCI) / Interaction paradigms / Virtual reality (1)
- Human-centered computing / Human computer interaction (HCI) / Interactiondevices (1)
- Human-centered computing / Human computerinteraction (HCI) / Interaction techniques (1)
- Hurwitz theorem (1)
- I-tasser (1)
- ICEP (1)
- IEEE 802.11e (1)
- IEEE 802.15.4 (1)
- IGFBP2 (1)
- III secretion (1)
- INS/LIDAR integrated navigation (1)
- IP (1)
- IT security (1)
- Image Aesthetic Assessment (1)
- Image Registration (1)
- ImageJ (1)
- Implementierung <Informatik> (1)
- Industrial internet (1)
- Industrie 4.0 (1)
- Inferenz <Künstliche Intelligenz> (1)
- Informatik (1)
- Information Extraction (1)
- Information Retrieval (1)
- Information Visualization (1)
- Information-Retrieval-System (1)
- Innovation Management (1)
- Innovationsmanagement (1)
- Instrument Control Toolbox (1)
- Intelligent Virtual Agents (1)
- InteractionSuitcase (1)
- Interaktion (1)
- Internet (1)
- Internet Protokoll (1)
- Invertierte Liste (1)
- IoT-driven processes (1)
- IronChip Evaluation Package (1)
- Isomorphie (1)
- Itinerare (1)
- Itineraries (1)
- JCAS (1)
- JSF (1)
- Jacobian matrix (1)
- Java 3D (1)
- Java <Programmiersprache> (1)
- Java Frameworks (1)
- Java Message Service (1)
- Julius-Maximilians-Universität Würzburg. Rechenzentrum (1)
- Kademlia (1)
- Kanalzugriff (1)
- Karte (1)
- Kartierung (1)
- Kathará (1)
- Kerneldensity estimation (1)
- Klassendiagramm (1)
- Klassifikation (1)
- Klima (1)
- Knowledge Discovery (1)
- Knowledge Management System (1)
- Knowledge Modeling (1)
- Knowledge representation (1)
- Knowledge-based System (1)
- Knowledge-based Systems Engineering (1)
- Kombinatorik (1)
- Kommunikation (1)
- Kommunikationsnetze (1)
- Komplexes System (1)
- Komplexitätsklasse (1)
- Komplexitätsklasse NP (1)
- Konvexe Zeichnungen (1)
- Konzeptsuche (1)
- Kooperierende mobile Roboter (1)
- Krankenhaus (1)
- Kreuzungsminimierung (1)
- Kryoelektronenmikroskopie (1)
- Kurve (1)
- LC-MS/MS (1)
- LFU (1)
- LRU (1)
- Land Cover Classification (1)
- Land plants (1)
- Landkartenbeschriftung (1)
- Landnutzungskartierung (1)
- Laser scanning (1)
- Lava (1)
- Lawhul-Mahfuz (1)
- Learning (1)
- Lee Smolin (1)
- Lehre (1)
- Lernen (1)
- Lidar (1)
- Lifetime spectroscopy (1)
- Lightning (1)
- Link rate adaptation (1)
- Linkratenanpassung (1)
- Linux (1)
- LoRa (1)
- LoRaWAN (1)
- LoRaWan (1)
- Logic Programming (1)
- Logische Programmierung (1)
- Lunar Caves (1)
- Lunar Exploration (1)
- MAC (1)
- MDR (1)
- MTC (1)
- MVC <Software> (1)
- Mackenzie-River-Delta (1)
- Mapping (1)
- Mars (1)
- Mashup (1)
- Mashup <Internet> (1)
- Mathematische Modellierung (1)
- Mathematisches Modell (1)
- Measurement (1)
- Medical Image Analysis (1)
- Medium <Physik> (1)
- Medizin (1)
- Mehrebenensimulation (1)
- Mehrfahrzeugsysteme (1)
- Mehrkriterielle Optimierung (1)
- Mehrpfadübertragung (1)
- Mehrschichtnetze (1)
- Mehrschichtsystem (1)
- Mensch-Maschine-Kommunikation (1)
- Mesh Networks (1)
- Mesh Netze (1)
- Metaverse (1)
- Methode (1)
- Methodologie (1)
- Microarray (1)
- Middleware (1)
- Miniaturisierung (1)
- Minimally invasive vascular intervention (1)
- Missionsbetrieb (1)
- Mobile Roboter (1)
- Mobiles Internet (1)
- Mobilfunk (1)
- Modell (1)
- Modellbasierte Diagnose (1)
- Modellierungstechniken (1)
- Modelling (1)
- Modularität (1)
- Molecular systematics (1)
- Mond (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)
- Multipath Transmission (1)
- Multiple-Choice Examination (1)
- Multiple-Choice Prüfungen (1)
- Mycoplasma (1)
- Mycoplasma pneumoniae (1)
- NP (1)
- NP-Vollständigkeit (1)
- NP-complete sets (1)
- NP-hartes Problem (1)
- NP-schweres Problem (1)
- Naïve Bayesian (1)
- Network Emulator (1)
- Network Experiments (1)
- Network Management (1)
- Network Measurements (1)
- Network Virtualization (1)
- Networks (1)
- Netzplantechnik (1)
- Netzplanung (1)
- Netzvirtualisierung (1)
- Netzwerkplanung (1)
- Netzwerkvirtualisierung (1)
- Neuromuscular junctions (1)
- Neuronales Netz (1)
- Newton Methods (1)
- Newton-Verfahren (1)
- Next Generation Networks (1)
- Nichtholonome Fahrzeuge (1)
- Nichtlineare Regelung (1)
- Nuclear RDNA (1)
- Object Detection (1)
- Object-Oriented Programming (1)
- Objektorientierte Programmierung (1)
- Open Source (1)
- Operator (1)
- Optical Flow (1)
- Optimale Kontrolle (1)
- Optimierungsproblem (1)
- Optimization on Lie Groups (1)
- Overlapping (1)
- Overlay (1)
- Overlay Netzwerke (1)
- Overlay networks (1)
- Overlays (1)
- P4-INT (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 Enhancing Proxies (1)
- Performance Management (1)
- Performance Modeling (1)
- Pfadberechnungselement (1)
- Picosatellite (1)
- Place of revelation (1)
- Planare Graphen (1)
- Planausführung (1)
- Planung (1)
- Planungssystem (1)
- Poisson surface reconstruction (1)
- PolSAR (1)
- Polyeder (1)
- Polypektomie (1)
- Positron annihilation spectroscopy (1)
- Post's Classes (1)
- Postsche Klassen (1)
- Prediction (1)
- Process Optimization (1)
- Processing Model (1)
- Processing model (1)
- Profile distances (1)
- Project Management (1)
- Projektmanagement (1)
- Prozessoptimierung (1)
- Publish-Subscribe-System (1)
- QUIC (1)
- QoS (1)
- Quality of Experience (QoE) (1)
- Quality of Experience QoE (1)
- Quality of Service (1)
- Quality of Service (QoS) (1)
- Quality-of-Experience (1)
- Quality-of-Service (1)
- Quality-of-Service (QoS) (1)
- Quantitative structure-property relationship modeling (QSPR) (1)
- Quantor (1)
- RBCL Gene-sequences (1)
- RGB-D (1)
- RNA sequencing (1)
- RRM (1)
- Radarfernerkundung (1)
- Raumdaten (1)
- Real-Time Operating Systems (1)
- Real-time (1)
- Rechenzentrum Universität Würzburg (1)
- Reconstruction of original text (1)
- Refactoring (1)
- Reference Architecture (1)
- Regelbasiertes System (1)
- Regelung (1)
- Registration (1)
- Registrierung (1)
- Registrierung <Bildverarbeitung> (1)
- Reguläre Sprache (1)
- Relief <Geografie> (1)
- Rendezvous (1)
- Reproducibility (1)
- Requirements Management (1)
- Resource and Performance Management (1)
- Ressourcen Management (1)
- Ressourcenallokation (1)
- Rettungsroboter (1)
- Risikomanagement (1)
- Risk Management (1)
- Robot (1)
- Roboter (1)
- Rule-based Systems (1)
- SARS-CoV-2 (1)
- SBA (1)
- SDN/NVF (1)
- SMLM (1)
- SNP (1)
- Scatter Plot (1)
- Scheduling (1)
- Search-and-Rescue (1)
- Secondary structure (1)
- Selbstkalibrierung (1)
- Self-Evaluation Programs (I2.399.780) (1)
- Self-calibration (1)
- Semantic Web (1)
- Semantics (1)
- Semantik (1)
- Sensing-aaS (1)
- Sensor (1)
- Septins (1)
- Service Mobility (1)
- Services (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 Performance Engineering (1)
- Software Performance Modeling (1)
- Software architecture (1)
- Software design (1)
- Software product lines (1)
- Softwareentwicklung (1)
- Source Code Visualization (1)
- Soziale Software (1)
- Spam-Mail (1)
- Spherical Robot (1)
- Spring (1)
- Stages of Prophet Mohammad’s messengership (1)
- Standardisierung (1)
- Standortproblem (1)
- Statistical classifiers (1)
- Statistics (1)
- Statistische Mechanik (1)
- Statistische Physik (1)
- Sternfreie Sprache (1)
- Steuerung (1)
- Stiffness (1)
- Stochastic Algorithms (1)
- Stochastik (1)
- Stochastikon (1)
- Stochastische Optimierung (1)
- Strahlentherapie (1)
- Straubing-Th´erien-Hierarchie (1)
- Straßennetzwerk (1)
- Straßenverkehr (1)
- Structure-from-Motion (1)
- Strukturelle Komplexität (1)
- Struts (1)
- Subgroup Mining (1)
- Subgruppenentdeckung (1)
- Substruktur (1)
- Suchverfahren (1)
- Support Vector Machine (1)
- Synapses (1)
- Synaptic vesicles (1)
- Synthetic Aperture Radar (1)
- System (1)
- Szenariogenerierung (1)
- TSN (1)
- TTL (1)
- TTL validation of data consistency (1)
- Teaching (1)
- Telematik (1)
- Terramechanics (1)
- Testbed (1)
- Text categorization (1)
- Text segmentation (1)
- Theoretical computer science (1)
- Thermografie (1)
- Time resolved measurements (1)
- Tomografie (1)
- Topografie (1)
- Torque (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)
- URLLC (1)
- Underwater Mapping (1)
- Underwater Scanning (1)
- Unmanned Aerial Vehicle (1)
- Unstetige Regelung (1)
- Usability (1)
- Use case (1)
- User Behavior (1)
- User Participation (1)
- V-antigen (1)
- VNF (1)
- VPN (1)
- Variability (1)
- Venus (1)
- Veranstaltung (1)
- Verbotenes Muster (1)
- Verbände (1)
- Verkehrslenkung (1)
- Verteilung von Inhalten (1)
- Vesicles (1)
- Video Quality Monitoring (1)
- Video Streaming (1)
- Videoübertragung (1)
- Virtualisierung (1)
- Virtuelles Netzwerk (1)
- Visibility (1)
- Visual Text Mining (1)
- Visual Tracking (1)
- Visualized Kathará (1)
- Voice-over-IP (VoIP) (1)
- Volltextsuche (1)
- Vorhersage (1)
- WH2 domain (1)
- WLAN (1)
- WNT (1)
- Warteschlangentheorie (1)
- Web service (1)
- WebGL (1)
- Webmail-System (1)
- Webservice Composition (1)
- Werkstattdiagnose (1)
- WhatsApp (1)
- Wheel (1)
- Winkel (1)
- Wire relaxation (1)
- Wireless LAN (1)
- Wireless Sensor/Actuator Systems (1)
- Wissensbanksystem (1)
- Wissensbasiertes System (1)
- Wissenschaftliche Beobachtung (1)
- Wissensendeckung (1)
- Worterweiterungen (1)
- Wrapper (1)
- Wrappers (1)
- XML model (1)
- XR-artificial intelligence combination (1)
- XR-artificial intelligence continuum (1)
- Yersinia enterocolitica (1)
- Yolk protein (1)
- YouTube (1)
- Zebrafish (1)
- Zeichnen von Graphen (1)
- Zeitdiskretes System (1)
- Zugangskontrolle (1)
- Zählprobleme (1)
- abgeschlossene Klassen (1)
- acrophobia (1)
- actin nucleation (1)
- adaptation (1)
- adaptation models (1)
- administrative boundary (1)
- admission control (1)
- adult learning (1)
- advertising effectiveness (1)
- aerodynamics (1)
- aerospace (1)
- aftermarket diagnostic (1)
- agent-based models (1)
- agents (1)
- agile Prozesse (1)
- agile processes (1)
- aging (1)
- alignment (1)
- anamnesis tool (1)
- aneurysm (1)
- angular schematization (1)
- annotation (1)
- anomaly detection (1)
- anomaly prediction (1)
- ant-colony optimization (1)
- anthropomorphism (1)
- anxiety (1)
- apixaban (1)
- application design (1)
- approximation algorithms (1)
- arabidopsis thaliana (1)
- arabidpsis thaliana (1)
- architectural design (1)
- arithmetic calculations (1)
- artificial intelligence education (1)
- artificial intelligence literacy (1)
- augmentation (1)
- automatic Layout (1)
- automatisches Layout (1)
- autonomic orchestration (1)
- autonomous (1)
- autonomous UAV (1)
- autorotation (1)
- availability (1)
- avatar embodiment (1)
- avatars (1)
- background knowledge (1)
- baseline detection (1)
- behavior (1)
- behavior change (1)
- behavior perception (1)
- bibliometric analysis (1)
- binary decision diagram (1)
- binary tanglegram (1)
- biofuel (1)
- biohybrid systems (1)
- bioinformatics (1)
- biological development (1)
- biomanufacturing (1)
- biosignals (1)
- bit (1)
- bit-parallel (1)
- boundary labeling (1)
- brain (1)
- building (1)
- caenorhabditis elegans (1)
- camera orientation (1)
- car-like robots (1)
- carbon (1)
- carboxylation (1)
- cardiac magnetic resonance (1)
- case study (1)
- caspase-3 (1)
- cell membranes (1)
- cerebral ischemia (1)
- certifying algorithm (1)
- chain cover (1)
- channel management (1)
- cisplatin (1)
- classification (1)
- climate (1)
- cloud-native (1)
- co-authorships (1)
- co-inventorships (1)
- cognitive impairment (1)
- coherence (1)
- collaboration (1)
- collision (1)
- colony-stimulating factor (1)
- combination therapy (1)
- communication models (1)
- communication networks (1)
- community detection (1)
- comparative sequence analysis (1)
- competitive location (1)
- complex traits (1)
- complexity (1)
- compressed sensing (1)
- computational (1)
- computational complexity (1)
- computer performance evaluation (1)
- computer virus (1)
- computergestützte Softwaretechnik (1)
- computers as social actors (1)
- concept search (1)
- condition prediction (1)
- congruence (1)
- connector (1)
- constrained forest (1)
- contact representation (1)
- container virtualization (1)
- content-based image retrieval (1)
- continuous-time SLAM (1)
- conversational agent (1)
- conversational agents (1)
- convex bipartite graph (1)
- convolutional neural network (1)
- corticotropin-releasing hormone (1)
- cost-sensitive learning (1)
- counting problems (1)
- crosstalk (1)
- crowdsourced QoE measurements (1)
- crowdsourced measurements (1)
- crowdsourced network measurements (1)
- cryo-EM (1)
- cryo-ET (1)
- crystal growth (1)
- crystallization (1)
- cultural and media studies (1)
- culturally aware (1)
- cuneiform (1)
- curves (1)
- cyber-physical systems (1)
- cybersickness (1)
- cytokine profiling (1)
- d3web.Train (1)
- dSTORM (1)
- data mining (1)
- data plane programming (1)
- data stream processing (1)
- data structure (1)
- data warehouse (1)
- dataplane programming (1)
- decision support system (1)
- decision-making (1)
- decission finding (1)
- decoding error rate (1)
- deep metric learning (1)
- definite clause grammars (1)
- deformation-based method (1)
- delay QoS exponent (1)
- delay bound violation probability (1)
- delay constrained (1)
- dementia (1)
- descent (1)
- design cycle (1)
- detection time simulation (1)
- diagnostic accuracy (1)
- dial a ride (1)
- differentiation (1)
- digital twin (1)
- dimensions of proximity (1)
- direct oral anticoagulants (1)
- direct thrombin inhibitor (1)
- discrete-time analysis (1)
- disease (1)
- disjoint multi-paths (1)
- disruption project (1)
- distance-based classifier (1)
- distributed control (1)
- docker (1)
- driving simulation (1)
- drug (1)
- drug-minded protein (1)
- dynamic flow migration (1)
- dynamic programming (1)
- dynamische Umgebungen (1)
- eHealth (1)
- early printed books (1)
- eco-metabolomics (1)
- ecological momentary assessment (1)
- edge labeled graphs (1)
- effective Bandwidth (1)
- efficient algorithm (1)
- electroencephalography (1)
- electrolytes (1)
- electronic health records (1)
- elementary mode analysis (1)
- elementary modes (1)
- elevated plus-maze (1)
- embedding techniques (1)
- emergent time (1)
- emotions (1)
- empathy (1)
- emulation (1)
- encryption (1)
- end user (1)
- endurance (1)
- energy efficiency (1)
- environmental sound (1)
- enzyme (1)
- event detection (1)
- event-related potentials-ERP (1)
- exercise intensity (1)
- experience (1)
- experimental evaluation (1)
- expertise framing (Min5-Max 8) (1)
- expression (1)
- expression signature (1)
- extended reality (1)
- extended reality (XR) (1)
- factor XA inhibitor (1)
- failure prediction (1)
- fast reroute (1)
- fault detection (1)
- feature matching (1)
- feature-matching (1)
- federated learning (1)
- few-shot learning (1)
- field-programmable architectures (1)
- field-programmable gate arrays (1)
- firewall (1)
- fixed-parameter tractability (1)
- flies (1)
- fluoroscopy (1)
- food quality (1)
- force dynamics (1)
- foreign language learning and teaching (1)
- formation driving (1)
- formation flight (1)
- fruit temperature (1)
- full-text search (1)
- functional analysis (1)
- future Internet architecture (1)
- future energy grid exploration (1)
- game mechanics (1)
- gamification (1)
- gamma (1)
- generative systems (1)
- genes (1)
- genetic algorithm (1)
- genetic regulatory network (1)
- geospatial data (1)
- global IPX network (1)
- graph (1)
- graph algorithm (1)
- graph decomposition (1)
- graphs (1)
- green systems biology (1)
- group-based communication (1)
- handwriting (1)
- handwritten artefact recognition (1)
- haptic data (1)
- hardness (1)
- hardware-in-the-loop simulation (1)
- hardware-in-the-loop streaming system (1)
- hepatotoxicity (1)
- heuristics (1)
- hierarchy (1)
- histidine kinase (1)
- historical images (1)
- hit ratio analysis and simulation (1)
- homology modeling (1)
- hospital data (1)
- human body weight (1)
- human computer interaction (HCI) (1)
- human-artificial intelligence interaction (1)
- human-artificial intelligence interface (1)
- human-centered design (1)
- human-centered, human-robot (1)
- humantechnology interaction (1)
- human–computer interaction (1)
- hybrid Diagnostic (1)
- hybrid access (1)
- hybride Diagnose (1)
- hypotonic (1)
- hypotonic solutions (1)
- illusion of self-motion (1)
- image classification (1)
- image processing (1)
- image schemas (1)
- imbalanced regression (1)
- immersive advertising (1)
- immersive classroom (1)
- immersive classroom management (1)
- immersive learning technologies (1)
- immunity (1)
- implicit association test (1)
- in situ analysis (1)
- independent crossing (1)
- induced matching (1)
- inflation (1)
- informal education (1)
- information extraction (1)
- information systems and information technology (1)
- inhibitor (1)
- intelligent transportation systems (1)
- intelligent vehicles (1)
- intelligent virtual agents (1)
- intelligent voice assistant (1)
- intelligente Applikationen (1)
- intention-behavior-gap (1)
- inter-coder reliability (1)
- interaction (1)
- interactive authoring system (1)
- interactive collation of textual variants (1)
- intercultural learning and teaching (1)
- interdisciplinary education (1)
- intermediate host (1)
- internal transcribed spacer 2 (1)
- internet protocol (1)
- internet traffic (1)
- interpolation (1)
- intervention design (1)
- intervention evaluation (1)
- intraoperative imaging (1)
- invasive vascular interventions (1)
- iowa gambling task (1)
- isotonic (1)
- key-insight extraction (1)
- kinect (1)
- labeling (1)
- land-cover area (1)
- landing (1)
- language-image pre-training (1)
- latency (1)
- lattices (1)
- layout recognition (1)
- learning environments (1)
- least cost (1)
- life-span regulation (1)
- lifetime spectroscopy (1)
- light-gated proteins (1)
- load balancing (1)
- local energy system (1)
- locomotion (1)
- logic programming (1)
- logistics (1)
- long-term analysis (1)
- lymphotoxicity (1)
- malaria (1)
- map projections (1)
- mapping (1)
- markers (1)
- mathematical model (1)
- measurement (1)
- media analysis (1)
- media equation (1)
- medical analytics (1)
- medical device regulation (1)
- medical device software (1)
- medical records (1)
- medieval manuscripts (1)
- meditation (1)
- membrane protein (1)
- membrane proteins (1)
- memory immune responses (1)
- metabolic flux (1)
- metabolism (1)
- metabolomics (1)
- metastasis (1)
- methylene blue (1)
- metro map (1)
- mice (1)
- microbes (1)
- mindfulness (1)
- misconceptions (1)
- mission operation (1)
- mixed reality (1)
- mixed-cultural (1)
- mixed-cultural settings (1)
- mobile application (1)
- mobile instant messaging (1)
- mobile messaging application (1)
- mobile streaming (1)
- model following (1)
- model output statistics (1)
- model predictive control (1)
- model-base diagnosis (1)
- model-based diagnosis (1)
- modeling techniques (1)
- modules (1)
- molecular systematics (1)
- monotone drawing (1)
- morphing (1)
- mouse (1)
- multi-vehicle formations (1)
- multi-vehicle rendezvous (1)
- multimodal fusion (1)
- multimodal interface (1)
- multimodal learning (1)
- multipath communication (1)
- multipath packet scheduling (1)
- multiple myeloma (1)
- multirotors (1)
- multiscale encoder (1)
- mutation (1)
- mycoplasma (1)
- n-Gramm (1)
- n-gram (1)
- nano-satellite (1)
- nanocellulose (1)
- natural interfaces (1)
- natural language processing (1)
- natural language processing · · · (1)
- natural user interfaces (1)
- network (1)
- network design (1)
- network planning (1)
- network softwarization (1)
- network upgrade (1)
- network virtualization (1)
- networked robotics (1)
- networking (1)
- neume notation (1)
- neural architecture (1)
- noise measurement (1)
- non-native accent (1)
- non-terrestrial networks (1)
- nonholonomic vehicles (1)
- nonhuman-primates (1)
- nonverbal behavior (1)
- object detection (1)
- octree (1)
- omics (1)
- open source (1)
- optical music recognition (1)
- optimization (1)
- orchestration (1)
- organogenesis (1)
- origin (1)
- overprovisioning (1)
- oxidative stress (1)
- packet reception method (1)
- painful (1)
- pangolin (1)
- particle picking (1)
- partitions (1)
- passage of time (1)
- passive haptic feedback (1)
- path computation (1)
- pathway (1)
- pattern perception (1)
- performance (1)
- performance analysis (1)
- performance evaluation (1)
- performance liquid chromatography (1)
- performance monitoring (1)
- performance prediction (1)
- permeability (1)
- pestis infection (1)
- phase space (1)
- phase transition (1)
- photorespiration (1)
- phylogenetic tree (1)
- phylogeny (1)
- place-illusion (1)
- plain orchestrating service (1)
- plan execution (1)
- plausibility (1)
- plausibility-illusion (1)
- pneumoniae (1)
- pneumonic plague (1)
- point cloud (1)
- point cloud compression (1)
- point-to-plane measure (1)
- point-to-point measure (1)
- pollution (1)
- pos (1)
- posets (1)
- positioning (1)
- precision horticulture (1)
- precision training (1)
- presence (1)
- private chat groups (1)
- procedural content generation (1)
- procedural fusion methods (1)
- process model (1)
- processing pipeline (1)
- progeria (1)
- promoter (1)
- prompt engineering (1)
- protein (1)
- protein chip (1)
- protein-interaction networks (1)
- pseudomas-syringae (1)
- psychomotor training (1)
- psychophyisology (1)
- public speaking (1)
- pulse simulation (1)
- q-Gramm (1)
- q-gram (1)
- quadcopter (1)
- quadcopters (1)
- quality assurance (1)
- quality evaluation (1)
- quality of experience (1)
- quality of experience prediction (1)
- quantification (1)
- qubit (1)
- radio resource management (1)
- radiology (1)
- ransomware (1)
- real world evidence (1)
- real-world application (1)
- realism (1)
- receding horizon control (1)
- receptor (1)
- recombinant protein rVE (1)
- recombination (1)
- recommender system (1)
- reconfiguration (1)
- regelbasierte Nachbearbeitung (1)
- reload cost (1)
- remote control (1)
- research methods (1)
- resilience (1)
- response regulator (1)
- ribosomal RNA (1)
- rich vehicle routing problem (1)
- richtersius coronifer (1)
- right angle crossing (1)
- road network (1)
- robotics (1)
- robustness (1)
- rotorcraft (1)
- rotors (1)
- routing (1)
- rule based post processing (1)
- sample weighting (1)
- satisfiability problems (1)
- scalability evaluation (1)
- scalable quadcopter (1)
- scenario creation (1)
- science, technology and society (1)
- secondary structure (1)
- secure group communication (1)
- self-adaptive (1)
- self-adaptive systems (1)
- self-assembly (1)
- self-aware computing systems (1)
- self-managing systems (1)
- semantic fusion (1)
- semantic understanding (1)
- semantic web (1)
- semantical aesthetic (1)
- semantische Ästhetik (1)
- sensitivity analysis (1)
- sensor devices (1)
- sensor fusion (1)
- sensor network (1)
- sensor networks (1)
- sentinel (1)
- sequence alignment (1)
- serious games (1)
- serum (1)
- service based software architecture (1)
- service brokerage (1)
- service-curve estimation (1)
- sesnsors (1)
- set (1)
- shootin-1 (1)
- short block-length (1)
- shortest path routing (1)
- signal processing (1)
- signaling traffic (1)
- simulation system (1)
- simultaneous embedding (1)
- single-electron transistors (1)
- skalierbare Diagnose (1)
- sketching (1)
- slam (1)
- smart meter data utilization (1)
- smooth orthogonal drawing (1)
- snow shoveling (1)
- social VR (1)
- social interaction (1)
- social relationship (1)
- social robot (1)
- social robotics (1)
- social role (1)
- socially interactive agents (1)
- software defined network (1)
- spam mail (1)
- spanning tree (1)
- spire (1)
- stability (1)
- stable state (1)
- standardization (1)
- state management (1)
- statistical validity (1)
- statistics and numerical data (1)
- stereotypes (1)
- stochastic thinking (1)
- stochastisches Denken (1)
- stream processing (1)
- stroke (1)
- structural complexity (1)
- student simulation (1)
- stylus (1)
- sun exposure (1)
- sunburn (1)
- superoxide-dismutase (1)
- supervised learning (1)
- surface model (1)
- survey (1)
- survival (1)
- sustainability (1)
- switching navigation (1)
- synthetic biology (1)
- synthetic pathways (1)
- system (1)
- system architecture design (1)
- systematic literature review (1)
- systematic review (1)
- table extraction (1)
- table understanding (1)
- taxonomy (1)
- teacher education (1)
- technology-supported learning (1)
- telematics (1)
- temperature (1)
- text categorization (1)
- text line detection (1)
- text supervision (1)
- theory (1)
- therapeutic application (1)
- thermal camera (1)
- thermal point cloud (1)
- time calibration (1)
- time perception (1)
- time series (1)
- timestamping method (1)
- tolerance (1)
- tomography (1)
- tonicity (1)
- tools (1)
- topology (1)
- training systems (1)
- trait anxiety (1)
- trajectory planning (1)
- transcription (1)
- transformations (1)
- transformer (1)
- translational neuroscience (1)
- transmission (1)
- transport microenvironments (1)
- transport protocols (1)
- transportation (1)
- tree (1)
- trust (1)
- trustworthiness (1)
- university network (1)
- unmanned aerial vehicle (1)
- unmanned aerial vehicles (1)
- usability evaluation (1)
- use cases (1)
- user experience (1)
- user interaction (1)
- user interfaces (1)
- user study (1)
- user-generated content (1)
- v (1)
- vaccine (1)
- validation (1)
- vection (1)
- vehicle dynamics (1)
- vehicular navigation (1)
- verbal behaviour (1)
- vernetzte Roboter (1)
- virtual agent interaction (1)
- virtual audience (1)
- virtual humans (1)
- virtual queue (1)
- virtual reality training (1)
- virtual stimuli (1)
- virtual tunnel (1)
- virtual-reality-continuum (1)
- visual analytics (1)
- visual proteomics (1)
- vitellogenin (1)
- voice assistant (1)
- voice-based artificial intelligence (1)
- vom Nutzer erfahrene Dienstgüte QoE (1)
- voting location (1)
- water stress (1)
- waypoint parameter (1)
- wearable (1)
- webmail system (1)
- wheel (1)
- wireless network (1)
- word clouds (1)
- word extensions (1)
- zooming (1)
- zukünftige Kommunikationsnetze (1)
- zukünftiges Internet (1)
- Ähnlichkeitsmaß (1)
- Überlappung (1)
Institute
- Institut für Informatik (203)
- Theodor-Boveri-Institut für Biowissenschaften (29)
- Institut Mensch - Computer - Medien (17)
- Institut für deutsche Philologie (17)
- Institut für Klinische Epidemiologie und Biometrie (7)
- Rechenzentrum (7)
- Center for Computational and Theoretical Biology (4)
- Graduate School of Science and Technology (3)
- Medizinische Klinik und Poliklinik II (3)
- Institut für Funktionsmaterialien und Biofabrikation (2)
Schriftenreihe
Sonstige beteiligte Institutionen
- Cologne Game Lab (2)
- Birmingham City University (1)
- DATE Lab, KITE Research Insititute, University Health Network, Toronto, Canada (1)
- EMBL Heidelberg (1)
- INAF Padova, Italy (1)
- Jacobs University Bremen, Germany (1)
- Open University of the Netherlands (1)
- Servicezentrum Medizin-Informatik (Universitätsklinikum) (1)
- Social and Technological Systems (SaTS) lab, School of Art, Media, Performance and Design, York University, Toronto, Canada (1)
- TH Köln (1)
Crowdsensing offers a cost-effective way to collect large amounts of environmental sensor data; however, the spatial distribution of crowdsensing sensors can hardly be influenced, as the participants carry the sensors, and, additionally, the quality of the crowdsensed data can vary significantly. Hybrid systems that use mobile users in conjunction with fixed sensors might help to overcome these limitations, as such systems allow assessing the quality of the submitted crowdsensed data and provide sensor values where no crowdsensing data are typically available. In this work, we first used a simulation study to analyze a simple crowdsensing system concerning the detection performance of spatial events to highlight the potential and limitations of a pure crowdsourcing system. The results indicate that even if only a small share of inhabitants participate in crowdsensing, events that have locations correlated with the population density can be easily and quickly detected using such a system. On the contrary, events with uniformly randomly distributed locations are much harder to detect using a simple crowdsensing-based approach. A second evaluation shows that hybrid systems improve the detection probability and time. Finally, we illustrate how to compute the minimum number of fixed sensors for the given detection time thresholds in our exemplary scenario.
In future telecommunication systems, we observe an increasing diversity of access networks. The separation of transport services and applications or services leads to multi-network services, i.e., a future service has to work transparently to the underlying network infrastructure. Multi-network services with edge-based intelligence, like P2P file sharing or the Skype VoIP service, impose new traffic control paradigms on the future Internet. Such services adapt the amount of consumed bandwidth to reach different goals. A selfish behavior tries to keep the QoE of a single user above a certain level. Skype, for instance, repeats voice samples depending on the perceived end-to-end loss. From the viewpoint of a single user, the replication of voice data overcomes the degradation caused by packet loss and enables to maintain a certain QoE. The cost for this achievement is a higher amount of consumed bandwidth. However, if the packet loss is caused by congestion in the network, this additionally required bandwidth even worsens the network situation. Altruistic behavior, on the other side, would reduce the bandwidth consumption in such a way that the pressure on the network is released and thus the overall network performance is improved. In this monograph, we analyzed the impact of the overlay, P2P, and QoE paradigms in future Internet applications and the interactions from the observing user behavior. The shift of intelligence toward the edge is accompanied by a change in the emerging user behavior and traffic profile, as well as a change from multi-service networks to multi-networks services. In addition, edge-based intelligence may lead to a higher dynamics in the network topology, since the applications are often controlled by an overlay network, which can rapidly change in size and structure as new nodes can leave or join the overlay network in an entirely distributed manner. As a result, we found that the performance evaluation of such services provides new challenges, since novel key performance factors have to be first identified, like pollution of P2P systems, and appropriate models of the emerging user behavior are required, e.g. taking into account user impatience. As common denominator of the presented studies in this work, we focus on a user-centric view when evaluating the performance of future Internet applications. For a subscriber of a certain application or service, the perceived quality expressed as QoE will be the major criterion of the user's satisfaction with the network and service providers. We selected three different case studies and characterized the application's performance from the end user's point of view. Those are (1) cooperation in mobile P2P file sharing networks, (2) modeling of online TV recording services, and (3) QoE of edge-based VoIP applications. The user-centric approach facilitates the development of new mechanisms to overcome problems arising from the changing user behavior. An example is the proposed CycPriM cooperation strategy, which copes with selfish user behavior in mobile P2P file sharing system. An adequate mechanism has also been shown to be efficient in a heterogeneous B3G network with mobile users conducting vertical handovers between different wireless access technologies. The consideration of the user behavior and the user perceived quality guides to an appropriate modeling of future Internet applications. In the case of the online TV recording service, this enables the comparison between different technical realizations of the system, e.g. using server clusters or P2P technology, to properly dimension the installed network elements and to assess the costs for service providers. Technologies like P2P help to overcome phenomena like flash crowds and improve scalability compared to server clusters, which may get overloaded in such situations. Nevertheless, P2P technology invokes additional challenges and different user behavior to that seen in traditional client/server systems. Beside the willingness to share files and the churn of users, peers may be malicious and offer fake contents to disturb the data dissemination. Finally, the understanding and the quantification of QoE with respect to QoS degradations permits designing sophisticated edge-based applications. To this end, we identified and formulated the IQX hypothesis as an exponential interdependency between QoE and QoS parameters, which we validated for different examples. The appropriate modeling of the emerging user behavior taking into account the user's perceived quality and its interactions with the overlay and P2P paradigm will finally help to design future Internet applications.
Performance Evaluation of Efficient Resource Management Concepts for Next Generation IP Networks
(2007)
Next generation networks (NGNs) must integrate the services of current circuit-switched telephone networks and packet-switched data networks. This convergence towards a unified communication infrastructure necessitates from the high capital expenditures (CAPEX) and operational expenditures (OPEX) due to the coexistence of separate networks for voice and data. In the end, NGNs must offer the same services as these legacy networks and, therefore, they must provide a low-cost packet-switched solution with real-time transport capabilities for telephony and multimedia applications. In addition, NGNs must be fault-tolerant to guarantee user satisfaction and to support business-critical processes also in case of network failures. A key technology for the operation of NGNs is the Internet Protocol (IP) which evolved to a common and well accepted standard for networking in the Internet during the last 25 years. There are two basically different approaches to achieve QoS in IP networks. With capacity overprovisioning (CO), an IP network is equipped with sufficient bandwidth such that network congestion becomes very unlikely and QoS is maintained most of the time. The second option to achieve QoS in IP networks is admission control (AC). AC represents a network-inherent intelligence that admits real-time traffic flows to a single link or an entire network only if enough resources are available such that the requirements on packet loss and delay can be met. Otherwise, the request of a new flow is blocked. This work focuses on resource management and control mechanisms for NGNs, in particular on AC and associated bandwidth allocation methods. The first contribution consists of a new link-oriented AC method called experience-based admission control (EBAC) which is a hybrid approach dealing with the problems inherent to conventional AC mechanisms like parameter-based or measurement-based AC (PBAC/MBAC). PBAC provides good QoS but suffers from poor resource utilization and, vice versa, MBAC uses resources efficiently but is susceptible to QoS violations. Hence, EBAC aims at increasing the resource efficiency while maintaining the QoS which increases the revenues of ISPs and postpones their CAPEX for infrastructure upgrades. To show the advantages of EBAC, we first review today’s AC approaches and then develop the concept of EBAC. EBAC is a simple mechanism that safely overbooks the capacity of a single link to increase its resource utilization. We evaluate the performance of EBAC by its simulation under various traffic conditions. The second contribution concerns dynamic resource allocation in transport networks which implement a specific network admission control (NAC) architecture. In general, the performance of different NAC systems may be evaluated by conventional methods such as call blocking analysis which has often been applied in the context of multi-service asynchronous transfer mode (ATM) networks. However, to yield more practical results than abstract blocking probabilities, we propose a new method to compare different AC approaches by their respective bandwidth requirements. To present our new method for comparing different AC systems, we first give an overview of network resource management (NRM) in general. Then we present the concept of adaptive bandwidth allocation (ABA) in capacity tunnels and illustrate the analytical performance evaluation framework to compare different AC systems by their capacity requirements. Different network characteristics influence the performance of ABA. Therefore, the impact of various traffic demand models and tunnel implementations, and the influence of resilience requirements is investigated. In conclusion, the resources in NGNs must be exclusively dedicated to admitted traffic to guarantee QoS. For that purpose, robust and efficient concepts for NRM are required to control the requested bandwidth with regard to the available transmission capacity. Sophisticated AC will be a key function for NRM in NGNs and, therefore, efficient resource management concepts like experience-based admission control and adaptive bandwidth allocation for admission-controlled capacity tunnels, as presented in this work are appealing for NGN solutions.
The work presents a performance evaluation and optimization of so-called overlay networks for content distribution in the Internet. Chapter 1 describes the importance which have such networks in today's Internet, for example, for the transmission of video content. The focus of this work is on overlay networks based on the peer-to-peer principle. These are characterized by the fact that users who download content, also contribute to the distribution process by sharing parts of the data to other users. This enables efficient content distribution because each user not only consumes resources in the system, but also provides its own resources. Chapter 2 of the monograph contains a detailed description of the functionality of today's most popular overlay network BitTorrent. It explains the various components and their interaction. This is followed by an illustration of why such overlay networks for Internet service providers (ISPs) are problematic. The reason lies in the large amount of inter-ISP traffic that is produced by these overlay networks. Since this inter-ISP traffic leads to high costs for ISPs, they try to reduce it by improved mechanisms for overlay networks. One optimization approach is the use of topology awareness within the overlay networks. It provides users of the overlay networks with information about the underlying physical network topology. This allows them to avoid inter-ISP traffic by exchanging data preferrentially with other users that are connected to the same ISP. Another approach to save inter-ISP traffic is caching. In this case the ISP provides additional computers in its network, called caches, which store copies of popular content. The users of this ISP can then obtain such content from the cache. This prevents that the content must be retrieved from locations outside of the ISP's network, and saves costly inter-ISP traffic in this way. In the third chapter of the thesis, the results of a comprehensive measurement study of overlay networks, which can be found in today's Internet, are presented. After a short description of the measurement methodology, the results of the measurements are described. These results contain data on a variety of characteristics of current P2P overlay networks in the Internet. These include the popularity of content, i.e., how many users are interested in specific content, the evolution of the popularity and the size of the files. The distribution of users within the Internet is investigated in detail. Special attention is given to the number of users that exchange a particular file within the same ISP. On the basis of these measurement results, an estimation of the traffic savings that can achieved by topology awareness is derived. This new estimation is of scientific and practical importance, since it is not limited to individual ISPs and files, but considers the whole Internet and the total amount of data exchanged in overlay networks. Finally, the characteristics of regional content are considered, in which the popularity is limited to certain parts of the Internet. This is for example the case of videos in German, Italian or French language. Chapter 4 of the thesis is devoted to the optimization of overlay networks for content distribution through caching. It presents a deterministic flow model that describes the influence of caches. On the basis of this model, it derives an estimate of the inter-ISP traffic that is generated by an overlay network, and which part can be saved by caches. The results show that the influence of the cache depends on the structure of the overlay networks, and that caches can also lead to an increase in inter-ISP traffic under certain circumstances. The described model is thus an important tool for ISPs to decide for which overlay networks caches are useful and to dimension them. Chapter 5 summarizes the content of the work and emphasizes the importance of the findings. In addition, it explains how the findings can be applied to the optimization of future overlay networks. Special attention is given to the growing importance of video-on-demand and real-time video transmissions.
In today's Internet, building overlay structures to provide a service is becoming more and more common. This approach allows for the utilization of client resources, thus being more scalable than a client-server model in this respect. However, in these architectures the quality of the provided service depends on the clients and is therefore more complex to manage. Resource utilization, both at the clients themselves and in the underlying network, determine the efficiency of the overlay application. Here, a trade-off exists between the resource providers and the end users that can be tuned via overlay mechanisms. Thus, resource management and traffic management is always quality-of-service management as well. In this monograph, the three currently significant and most widely used overlay types in the Internet are considered. These overlays are implemented in popular applications which only recently have gained importance. Thus, these overlay networks still face real-world technical challenges which are of high practical relevance. We identify the specific issues for each of the considered overlays, and show how their optimization affects the trade-offs between resource efficiency and service quality. Thus, we supply new insights and system knowledge that is not provided by previous work.
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.
Web caches often use a Time-to-live (TTL) limit to validate data consistency with web servers. We study the impact of TTL constraints on the hit ratio of basic strategies in caches of fixed size. We derive analytical results and confirm their accuracy in comparison to simulations. We propose a score-based caching method with awareness of the current TTL per data for improving the hit ratio close to the upper bound.
In this work, we describe the network from data collection to data processing and storage as a system based on different layers. We outline the different layers and highlight major tasks and dependencies with regard to energy consumption and energy efficiency. With this view, we can outwork challenges and questions a future system architect must answer to provide a more sustainable, green, resource friendly, and energy efficient application or system. Therefore, all system layers must be considered individually but also altogether for future IoT solutions. This requires, in particular, novel sustainability metrics in addition to current Quality of Service and Quality of Experience metrics to provide a high power, user satisfying, and sustainable network.
The issue of sustainability is at the top of the political and societal agenda, being considered of extreme importance and urgency. Human individual action impacts the environment both locally (e.g., local air/water quality, noise disturbance) and globally (e.g., climate change, resource use). Urban environments represent a crucial example, with an increasing realization that the most effective way of producing a change is involving the citizens themselves in monitoring campaigns (a citizen science bottom-up approach). This is possible by developing novel technologies and IT infrastructures enabling large citizen participation. Here, in the wider framework of one of the first such projects, we show results from an international competition where citizens were involved in mobile air pollution monitoring using low cost sensing devices, combined with a web-based game to monitor perceived levels of pollution. Measures of shift in perceptions over the course of the campaign are provided, together with insights into participatory patterns emerging from this study. Interesting effects related to inertia and to direct involvement in measurement activities rather than indirect information exposure are also highlighted, indicating that direct involvement can enhance learning and environmental awareness. In the future, this could result in better adoption of policies towards decreasing pollution.
The strict restrictions introduced by the COVID-19 lockdowns, which started from March 2020, changed people’s daily lives and habits on many different levels. In this work, we investigate the impact of the lockdown on the communication behavior in the mobile instant messaging application WhatsApp. Our evaluations are based on a large dataset of 2577 private chat histories with 25,378,093 messages from 51,973 users. The analysis of the one-to-one and group conversations confirms that the lockdown severely altered the communication in WhatsApp chats compared to pre-pandemic time ranges. In particular, we observe short-term effects, which caused an increased message frequency in the first lockdown months and a shifted communication activity during the day in March and April 2020. Moreover, we also see long-term effects of the ongoing pandemic situation until February 2021, which indicate a change of communication behavior towards more regular messaging, as well as a persisting change in activity during the day. The results of our work show that even anonymized chat histories can tell us a lot about people’s behavior and especially behavioral changes during the COVID-19 pandemic and thus are of great relevance for behavioral researchers. Furthermore, looking at the pandemic from an Internet provider perspective, these insights can be used during the next pandemic, or if the current COVID-19 situation worsens, to adapt communication networks to the changed usage behavior early on and thus avoid network congestion.
Natural walking in virtual reality games is constrained by the physical boundaries defined by the size of the player’s tracking space. Impossible spaces, a redirected walking technique, enlarge the virtual environment by creating overlapping architecture and letting multiple locations occupy the same physical space. Within certain thresholds, this is subtle to the player. In this paper, we present our approach to implement such impossible spaces and describe how we handled challenges like objects with simulated physics or precomputed global illumination.
Mobile 3D fluoroscopes have become increasingly available in neurosurgical operating rooms. We recently reported its use for imaging cerebral vascular malformations and aneurysms. This study was conducted to evaluate various radiation settings for the imaging of cerebral aneurysms before and after surgical occlusion. Eighteen patients with cerebral aneurysms with the indication for surgical clipping were included in this prospective analysis. Before surgery the patients were randomized into one of three different scan protocols according (default settings of the 3D fluoroscope): Group 1: 110 kV, 80 mA (enhanced cranial mode), group 2: 120 kV, 64 mA (lumbar spine mode), group 3: 120 kV, 25 mA (head/neck settings). Prior to surgery, a rotational fluoroscopy scan (duration 24 s) was performed without contrast agent followed by another scan with 50 ml of intravenous iodine contrast agent. The image files of both scans were transferred to an Apple PowerMac(R) workstation, subtracted and reconstructed using OsiriX(R) MD 10.0 software. The procedure was repeated after clip placement. The image quality regarding preoperative aneurysm configuration and postoperative assessment of aneurysm occlusion and vessel patency was analyzed by 2 independent reviewers using a 6-grade scale. This technique quickly supplies images of adequate quality to depict intracranial aneurysms and distal vessel patency after aneurysm clipping. Regarding these features, a further optimization to our previous protocol seems possible lowering the voltage and increasing tube current. For quick intraoperative assessment, image subtraction seems not necessary. Thus, a native scan without a contrast agent is not necessary. Further optimization may be possible using a different contrast injection protocol.
At the center of the Internet’s protocol stack stands the Internet Protocol (IP) as a common denominator that enables all communication. To make routing efficient, resilient, and scalable, several aspects must be considered. Care must be taken that traffic is well balanced to make efficient use of the existing network resources, both in failure free operation and in failure scenarios.
Finding the optimal routing in a network is an NP-complete problem. Therefore, routing optimization is usually performed using heuristics. This dissertation shows that a routing optimized with one objective function is often not good when looking at other objective functions. It can even be worse than unoptimized routing with respect to that objective function. After looking at failure-free routing and traffic distribution in different failure scenarios, the analysis is extended to include the loop-free alternate (LFA) IP fast reroute mechanism. Different application scenarios of LFAs are examined and a special focus is set on the fact that LFAs usually cannot protect all traffic in a network even against single link failures. Thus, the routing optimization for LFAs is targeted on both link utilization and failure coverage. Finally, the pre-congestion notification mechanism PCN for network admission control and overload protection is analyzed and optimized. Different design options for implementing the protocol are compared, before algorithms are developed for the calculation and optimization of protocol parameters and PCN-based routing.
The second part of the thesis tackles a routing problem that can only be resolved on a global scale. The scalability of the Internet is at risk since a major and intensifying growth of the interdomain routing tables has been observed. Several protocols and architectures are analyzed that can be used to make interdomain routing more scalable. The most promising approach is the locator/identifier (Loc/ID) split architecture which separates routing from host identification. This way, changes in connectivity, mobility of end hosts, or traffic-engineering activities are hidden from the routing in the core of the Internet and the routing tables can be kept much smaller. All of the currently proposed Loc/ID split approaches have their downsides. In particular, the fact that most architectures use the ID for routing outside the Internet’s core is a poor design, which inhibits many of the possible features of a new routing architecture. To better understand the problems and to provide a solution for a scalable routing design that implements a true Loc/ID split, the new GLI-Split protocol is developed in this thesis, which provides separation of global and local routing and uses an ID that is independent from any routing decisions.
Besides GLI-Split, several other new routing architectures implementing Loc/ID split have been proposed for the Internet. Most of them assume that a mapping system is queried for EID-to-RLOC mappings by an intermediate node at the border of an edge network. When the mapping system is queried by an intermediate node, packets are already on their way towards their destination, and therefore, the mapping system must be fast, scalable, secure, resilient, and should be able to relay packets without locators to nodes that can forward them to the correct destination. The dissertation develops a classification for all proposed mapping system architectures and shows their similarities and differences. Finally, the fast two-level mapping system FIRMS is developed. It includes security and resilience features as well as a relay service for initial packets of a flow when intermediate nodes encounter a cache miss for the EID-to-RLOC mapping.
Operators of Higher Order
(1998)
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.
This paper presents a novel concept to extend state-of-the-art buffer monitoring with additional measures to estimate service-curves. The online algorithm for service-curve estimation replaces the state-of-the-art timestamp logging, as we expect it to overcome the main disadvantages of generating a huge amount of data and using a lot of CPU resources to store the data to a file during operation. We prove the accuracy of the online-algorithm offline with timestamp data and compare the derived bounds to the measured delay and backlog. We also do a proof-of- concept of the online-algorithm, implement it in LabVIEW and compare its performance to the timestamp logging by CPU load and data-size of the log-file. However, the implementation is still work-in-progress.
In the course of the growth of the Internet and due to increasing availability of data, over the last two decades, the field of network science has established itself as an own area of research. With quantitative scientists from computer science, mathematics, and physics working on datasets from biology, economics, sociology, political sciences, and many others, network science serves as a paradigm for interdisciplinary research.
One of the major goals in network science is to unravel the relationship between topological graph structure and a network’s function. As evidence suggests, systems from the same fields, i.e. with similar function, tend to exhibit similar structure. However, it is still vague whether a similar graph structure automatically implies likewise function. This dissertation aims at helping to bridge this gap, while particularly focusing on the role of triadic structures.
After a general introduction to the main concepts of network science, existing work devoted to the relevance of triadic substructures is reviewed. A major challenge in modeling triadic structure is the fact that not all three-node subgraphs can be specified independently
of each other, as pairs of nodes may participate in multiple of those triadic subgraphs.
In order to overcome this obstacle, we suggest a novel class of generative network models based on so called Steiner triple systems. The latter are partitions of a graph’s vertices into pair-disjoint triples (Steiner triples). Thus, the configurations on Steiner triples can be specified independently of each other without overdetermining the network’s link
structure.
Subsequently, we investigate the most basic realization of this new class of models. We call it the triadic random graph model (TRGM). The TRGM is parametrized by a probability distribution over all possible triadic subgraph patterns. In order to generate a network instantiation of the model, for all Steiner triples in the system, a pattern is drawn from the distribution and adjusted randomly on the Steiner triple. We calculate the degree distribution of the TRGM analytically and find it to be similar to a Poissonian distribution. Furthermore, it is shown that TRGMs possess non-trivial triadic structure. We discover inevitable correlations in the abundance of certain triadic subgraph
patterns which should be taken into account when attributing functional relevance to particular motifs – patterns which occur significantly more frequently than expected at random. Beyond, the strong impact of the probability distributions on the Steiner triples on the occurrence of triadic subgraphs over the whole network is demonstrated. This interdependence allows us to design ensembles of networks with predefined triadic substructure. Hence, TRGMs help to overcome the lack of generative models needed for assessing the relevance of triadic structure.
We further investigate whether motifs occur homogeneously or heterogeneously distributed over a graph. Therefore, we study triadic subgraph structures in each node’s neighborhood individually. In order to quantitatively measure structure from an individual node’s perspective, we introduce an algorithm for node-specific pattern mining for both directed unsigned, and undirected signed networks. Analyzing real-world datasets, we find that there are networks in which motifs are distributed highly heterogeneously, bound to the proximity of only very few nodes. Moreover, we observe indication for the potential sensitivity of biological systems to a targeted removal of these critical vertices. In addition, we study whole graphs with respect to the homogeneity and homophily of their node-specific triadic structure. The former describes the similarity of subgraph distributions in the neighborhoods of individual vertices. The latter quantifies whether connected vertices
are structurally more similar than non-connected ones. We discover these features to be characteristic for the networks’ origins. Moreover, clustering the vertices of graphs regarding their triadic structure, we investigate structural groups in the neural network of C. elegans, the international airport-connection network, and the global network of diplomatic sentiments between countries. For the latter we find evidence for the instability of triangles considered socially unbalanced according to sociological theories.
Finally, we utilize our TRGM to explore ensembles of networks with similar triadic substructure in terms of the evolution of dynamical processes acting on their nodes. Focusing on oscillators, coupled along the graphs’ edges, we observe that certain triad motifs impose a clear signature on the systems’ dynamics, even when embedded in a larger
network structure.
Cooperative, connected and automated mobility (CCAM) systems depend on a reliable communication to provide their service and more crucially to ensure the safety of users. One way to ensure the reliability of a data transmission is to use multiple transmission technologies in combination with redundant flows. In this paper, we describe a system requiring multipath communication in the context of CCAM. To this end, we introduce a data plane-based scheduler that uses replication and integration modules to provide redundant and transparent multipath communication. We provide an analytical model for the full replication module of the system and give an overview of how and where the data-plane scheduler components can be realized.
Cooperative, connected and automated mobility (CCAM) systems depend on a reliable communication to provide their service and more crucially to ensure the safety of users. One way to ensure the reliability of a data transmission is to use multiple transmission technologies in combination with redundant flows. In this paper, we describe a system requiring multipath communication in the context of CCAM. To this end, we introduce a data plane-based scheduler that uses replication and integration modules to provide redundant and transparent multipath communication. We provide an analytical model for the full replication module of the system and give an overview of how and where the data-plane scheduler components can be realized.
This article introduces the Off-The-Shelf Stylus (OTSS), a framework for 2D interaction (in 3D) as well as for handwriting and sketching with digital pen, ink, and paper on physically aligned virtual surfaces in Virtual, Augmented, and Mixed Reality (VR, AR, MR: XR for short). OTSS supports self-made XR styluses based on consumer-grade six-degrees-of-freedom XR controllers and commercially available styluses. The framework provides separate modules for three basic but vital features: 1) The stylus module provides stylus construction and calibration features. 2) The surface module provides surface calibration and visual feedback features for virtual-physical 2D surface alignment using our so-called 3ViSuAl procedure, and surface interaction features. 3) The evaluation suite provides a comprehensive test bed combining technical measurements for precision, accuracy, and latency with extensive usability evaluations including handwriting and sketching tasks based on established visuomotor, graphomotor, and handwriting research. The framework’s development is accompanied by an extensive open source reference implementation targeting the Unity game engine using an Oculus Rift S headset and Oculus Touch controllers. The development compares three low-cost and low-tech options to equip controllers with a tip and includes a web browser-based surface providing support for interacting, handwriting, and sketching. The evaluation of the reference implementation based on the OTSS framework identified an average stylus precision of 0.98 mm (SD = 0.54 mm) and an average surface accuracy of 0.60 mm (SD = 0.32 mm) in a seated VR environment. The time for displaying the stylus movement as digital ink on the web browser surface in VR was 79.40 ms on average (SD = 23.26 ms), including the physical controller’s motion-to-photon latency visualized by its virtual representation (M = 42.57 ms, SD = 15.70 ms). The usability evaluation (N = 10) revealed a low task load, high usability, and high user experience. Participants successfully reproduced given shapes and created legible handwriting, indicating that the OTSS and it’s reference implementation is ready for everyday use. We provide source code access to our implementation, including stylus and surface calibration and surface interaction features, making it easy to reuse, extend, adapt and/or replicate previous results (https://go.uniwue.de/hci-otss).
Having a mixed-cultural membership becomes increasingly common in our modern society. It is thus beneficial in several ways to create Intelligent Virtual Agents (IVAs) that reflect a mixed-cultural background as well, e.g., for educational settings. For research with such IVAs, it is essential that they are classified as non-native by members of a target culture. In this paper, we focus on variations of IVAs’ speech to create the impression of non-native speakers that are identified as such by speakers of two different mother tongues. In particular, we investigate grammatical mistakes and identify thresholds beyond which the agents is clearly categorised as a non-native speaker. Therefore, we conducted two experiments: one for native speakers of German, and one for native speakers of English. Results of the German study indicate that beyond 10% of word order mistakes and 25% of infinitive mistakes German-speaking IVAs are perceived as non-native speakers. Results of the English study indicate that beyond 50% of omission mistakes and 50% of infinitive mistakes English-speaking IVAs are perceived as non-native speakers. We believe these thresholds constitute helpful guidelines for computational approaches of non-native speaker generation, simplifying research with IVAs in mixed-cultural settings.
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).
Consider the situation where two or more images are taken from the same object. After taking the first image, the object is moved or rotated so that the second recording depicts it in a different manner. Additionally, take heed of the possibility that the imaging techniques may have also been changed. One of the main problems in image processing is to determine the spatial relation between such images. The corresponding process of finding the spatial alignment is called “registration”. In this work, we study the optimization problem which corresponds to the registration task. Especially, we exploit the Lie group structure of the set of transformations to construct efficient, intrinsic algorithms. We also apply the algorithms to medical registration tasks. However, the methods developed are not restricted to the field of medical image processing. We also have a closer look at more general forms of optimization problems and show connections to related tasks.
State Management at line rate is crucial for critical applications in next-generation networks. P4 is a language used in software-defined networking to program the data plane. The data plane can profit in many circumstances when it is allowed to manage its state without any detour over a controller. This work is based on a previous study by investigating the potential and performance of add-on-miss insertions of state by the data plane. The state keeping capabilities of P4 are limited regarding the amount of data and the update frequency. We follow the tentative specification of an upcoming portable-NIC-architecture and implement these changes into the software P4 target T4P4S. We show that insertions are possible with only a slight overhead compared to lookups and evaluate the influence of the rate of insertions on their latency.
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.
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.
The successful development and classroom integration of Virtual (VR) and Augmented Reality (AR) learning environments requires competencies and content knowledge with respect to media didactics and the respective technologies. The paper discusses a pedagogical concept specifically aiming at the interdisciplinary education of pre-service teachers in collaboration with human-computer interaction students. The students’ overarching goal is the interdisciplinary realization and integration of VR/AR learning environments in teaching and learning concepts. To assist this approach, we developed a specific tutorial guiding the developmental process. We evaluate and validate the effectiveness of the overall pedagogical concept by analyzing the change in attitudes regarding 1) the use of VR/AR for educational purposes and in competencies and content knowledge regarding 2) media didactics and 3) technology. Our results indicate a significant improvement in the knowledge of media didactics and technology. We further report on four STEM learning environments that have been developed during the seminar.
No abstract available
This paper discusses the problem of finding multiple shortest disjoint paths in modern communication networks, which is essential for ultra-reliable and time-sensitive applications. Dijkstra’s algorithm has been a popular solution for the shortest path problem, but repetitive use of it to find multiple paths is not scalable. The Multiple Disjoint Path Algorithm (MDPAlg), published in 2021, proposes the use of a single full graph to construct multiple disjoint paths. This paper proposes modifications to the algorithm to include a delay constraint, which is important in time-sensitive applications. Different delay constraint least-cost routing algorithms are compared in a comprehensive manner to evaluate the benefits of the adapted MDPAlg algorithm. Fault tolerance, and thereby reliability, is ensured by generating multiple link-disjoint paths from source to destination.
Practical optimization problems often comprise several incomparable and conflicting objectives. When booking a trip using several means of transport, for instance, it should be fast and at the same time not too expensive. The first part of this thesis is concerned with the algorithmic solvability of such multiobjective optimization problems. Several solution notions are discussed and compared with respect to their difficulty. Interestingly, these solution notions are always equally difficulty for a single-objective problem and they differ considerably already for two objectives (unless P = NP). In this context, the difference between search and decision problems is also investigated in general. Furthermore, new and improved approximation algorithms for several variants of the traveling salesperson problem are presented. Using tools from discrepancy theory, a general technique is developed that helps to avoid an obstacle that is often hindering in multiobjective approximation: The problem of combining two solutions such that the new solution is balanced in all objectives and also mostly retains the structure of the original solutions. The second part of this thesis is dedicated to several aspects of systems of equations for (formal) languages. Firstly, conjunctive and Boolean grammars are studied, which are extensions of context-free grammars by explicit intersection and complementation operations, respectively. Among other results, it is shown that one can considerably restrict the union operation on conjunctive grammars without changing the generated language. Secondly, certain circuits are investigated whose gates do not compute Boolean values but sets of natural numbers. For these circuits, the equivalence problem is studied, i.\,e.\ the problem of deciding whether two given circuits compute the same set or not. It is shown that, depending on the allowed types of gates, this problem is complete for several different complexity classes and can thus be seen as a parametrized) representative for all those classes.
Die Dissertation befaßt sich mit der Entwicklung einer multimedialen, datenbankgestützten Lehr- und Lernplattform. Die entwickelten Module ermöglichen und erweitern nicht nur die Möglichkeit des Selbststudiums für den Studenten sondern erleichtern auch die Arbeit der Dozenten. Außerdem wird auch die Zusammenarbeit und der Austausch von Lernobjekten zwischen verschiedenen Institutionen ermöglicht. In der Lehr- und Lernplattform können verschiedene Lernobjekt-Typen verwaltet werden. Exemplarisch wurden die Typen Bilder, 3D-Animationen, Vorlesungen, Lerntexte, Fallbeispiele und Quizelemente integriert. Die Lehr- und Lernplattform besteht aus drei Bausteinen: 1. In der Lernobjekt-Datenbank werden alle Lernobjekt-Typen und Lernobjekte verwaltet. 2. Autorenwerkzeuge dienen zur Erstellung von Lernobjekten. 3. In der Lernplattform werden die Lernobjekte den Studenten zum (Selbst-)Lernen präsentiert. Neben den Vorteilen, die der Einsatz von E-Learning im allgemeinen bietet, wie die flexible Lernorganisation oder die Nutzung von Lerninhalten unabhängig von Ort und Zeit, zeichnet sich die entwickelte Lehr- und Lernplattform besonders durch folgende Punkte aus: Generierung von Lerninhalten höherer Qualität durch multizentrische Expertenbündelung und Arbeitsteilung, Erweiterbarkeit auf andere, neue Lernobjekt-Typen, Verwaltbarkeit, Konsistenz, Flexibilität, geringer Verwaltungsaufwand, Navigationsmöglichkeiten für den Studenten, Personalisierbarkeit und Konformität zu internationalen Standards. Sowohl bei der Modellierung als auch bei der Umsetzung wurde darauf geachtet, möglichst gut die Anforderungen der Dermatologie bei gleichzeitiger Erweiterbarkeit auf andere, ähnliche Szenarien zu erfüllen. Besonders einfach sollte die Anpassung der Plattform für andere bildorientierte Disziplinen sein.
Network planning has come to great importance during the past decades. Today's telecommunication, traffic systems, and logistics would not have been evolved to the current state without careful analysis of the underlying network problems and precise implementation of the results obtained from those examinations. Graphs with node and arc attributes are a very useful tool to model realistic applications, while on the other hand they are well understood in theory. We investigate network design problems which are motivated particularly from applications in communication networks and logistics. Those problems include the search for homogeneous subgraphs in edge labeled graphs where either the total number of labels or the reload cost are subject to optimize. Further, we investigate some variants of the dial a ride problem. On the other hand, we use node and edge upgrade models to deal with the fact that in many cases one prefers to change existing networks rather than implementing a newly computed solution from scratch. We investigate the construction of bottleneck constrained forests under a node upgrade model, as well as several flow cost problems under a edge based upgrade model. All problems are examined within a framework of multi-criteria optimization. Many of the problems can be shown to be NP-hard, with the consequence that, under the widely accepted assumption that P is not equal to NP, there cannot exist efficient algorithms for solving the problems. This motivates the development of approximation algorithms which compute near-optimal solutions with provable performance guarantee in polynomial time.
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.
Die Realisierung einer koordinierten und effektiven Fortbewegung für einen mobilen Roboter in natürlichen, sich kontinuierlich verändernden Umgebungen unter sich ebenso bewegenden Hindernissen ist eine komplexe Aufgabe, die die Lösung einer Reihe von Unterproblemen voraussetzt. Die vorliegende Arbeit beschäftigt sich sowohl mit den Themen der Wahrnehmung und Fortbewegung in veränderlichen Umgebungen, als auch mit Methoden zur Analyse der Hindernisbewegungen in Zusammenhang mit der Roboterbewegung selbst. Die Wahrnehmung wird in erster Linie anhand von Laserscannern betrachtet, und ein entsprechendes Verfahren zur Hindernisdetektion und -verfolung wird vorgestellt. Dabei werden Verfahren der globalen Netzwerkoptimierung eingesetzt, um Korrespondenzen zwischen Objekten aus den Einzelbildern herzustellen, was sich positiv auf die Robustheit gegenüber Störungen durch sporadische kleine Objekte auswirkt. Die Navigation basiert auf einer Adaption des sog. "Velocity Obstacle" Ansatzes auf die vorhandene Fahrzeugkinematik, und eine kooperative Bewegungskoordination (Roboter begleitet Mensch) wird durch eine geeignete Auswahlregel für kollisionsfreie Geschwindigkeiten realisiert. Anschließend werden verschiedene Distanzmaße eingeführt, anhand derer sich etwa der Pfad des Roboters mit dem Pfad seiner Begleitperson vergleichen lässt. Weiter wird eine Klassifizierung von Situationen vorgenommen, in die der Roboter potentiell involviert sein kann, und nach einer Übersicht über existierende Ansätze zur automatischen Intentionserkennung wird ein praktikabler Ansatz zur Erkennung gezielter Behinderungen eines mobilen Roboters vorgestellt. Die Arbeit schließt mit einem neuen Ansatz der Bewegungsplanung in dynamischen Umgebungen, der auf rekursiven Modellen des Roboters von seinem Gegenüber basiert, d.h. der Roboter berechnet zunächst, wie er sich in der Situation des (intelligenten, beweglichen) Hindernisses fortbewegen würde, und bezieht dies in die Entscheidung über die eigene Fortbewegung mit ein. Je nach Rekursionstiefe entstehen hierdurch Verhaltensweisen unterschiedlichen Charakters für den Roboter.
This work focuses on coordination methods and the control of motion in groups of nonholonomic wheeled mobile robots, in particular of the car-like type. These kind of vehicles are particularly restricted in their mobility. In the main part of this work the two problems of formation motion coordination and of rendezvous in distributed multi-vehicle systems are considered. We introduce several enhancements to an existing motion planning approach for formations of nonholonomic mobile robots. Compared to the original method, the extended approach is able to handle time-varying reference speeds as well as adjustments of the formation's shape during reference trajectory segments with continuously differentiable curvature. Additionally, undesired discontinuities in the speed and steering profiles of the vehicles are avoided. Further, the scenario of snow shoveling on an airfield by utilizing multiple formations of autonomous snowplows is discussed. We propose solutions to the subproblems of motion planning for the formations and tracking control for the individual vehicles. While all situations that might occur have been tested in a simulation environment, we also verified the developed tracking controller in real robot hardware experiments. The task of the rendezvous problem in groups of car-like robots is to drive all vehicles to a common position by means of decentralized control laws. Typically there exists no direct interaction link between all of the vehicles. In this work we present decentralized rendezvous control laws for vehicles with free and with bounded steering. The convergence properties of the approaches are analyzed by utilizing Lyapunov based techniques. Furthermore, they are evaluated within various simulation experiments, while the bounded steering case is also verified within laboratory hardware experiments. Finally we introduce a modification to the bounded steering system that increases the convergence speed at the expense of a higher traveled distance of the vehicles.
In the future Internet, the people-centric communication paradigm will be complemented by a ubiquitous communication among people and devices, or even a communication between devices. This comes along with the need for a more flexible, cheap, widely available Internet access. Two types of wireless networks are considered most appropriate for attaining those goals. While wireless sensor networks (WSNs) enhance the Internet’s reach by providing data about the properties of the environment, wireless mesh networks (WMNs) extend the Internet access possibilities beyond the wired backbone. This monograph contains four chapters which present modeling and optimization methods for WSNs and WMNs. Minimizing energy consumptions is the most important goal of WSN optimization and the literature consequently provides countless energy consumption models. The first part of the monograph studies to what extent the used energy consumption model influences the outcome of analytical WSN optimizations. These considerations enable the second contribution, namely overcoming the problems on the way to a standardized energy-efficient WSN communication stack based on IEEE 802.15.4 and ZigBee. For WMNs both problems are of minor interest whereas the network performance has a higher weight. The third part of the work, therefore, presents algorithms for calculating the max-min fair network throughput in WMNs with multiple link rates and Internet gateway. The last contribution of the monograph investigates the impact of the LRA concept which proposes to systematically assign more robust link rates than actually necessary, thereby allowing to exploit the trade-off between spatial reuse and per-link throughput. A systematical study shows that a network-wide slightly more conservative LRA than necessary increases the throughput of a WMN where max-min fairness is guaranteed. It moreover turns out that LRA is suitable for increasing the performance of a contention-based WMN and is a valuable optimization tool.
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.
With the progress in robotics research the human machine interfaces reach more and more the status of being the major limiting factor for the overall system performance of a system for remote navigation and coordination of robots. In this monograph it is elaborated how mixed reality technologies can be applied for the user interfaces in order to increase the overall system performance. Concepts, technologies, and frameworks are developed and evaluated in user studies which enable for novel user-centered approaches to the design of mixed-reality user interfaces for remote robot operation. Both the technological requirements and the human factors are considered to achieve a consistent system design. Novel technologies like 3D time-of-flight cameras are investigated for the application in the navigation tasks and for the application in the developed concept of a generic mixed reality user interface. In addition it is shown how the network traffic of a video stream can be shaped on application layer in order to reach a stable frame rate in dynamic networks. The elaborated generic mixed reality framework enables an integrated 3D graphical user interface. The realized spatial integration and visualization of available information reduces the demand for mental transformations for the human operator and supports the use of immersive stereo devices. The developed concepts make also use of the fact that local robust autonomy components can be realized and thus can be incorporated as assistance systems for the human operators. A sliding autonomy concept is introduced combining force and visual augmented reality feedback. The force feedback component allows rendering the robot's current navigation intention to the human operator, such that a real sliding autonomy with seamless transitions is achieved. The user-studies prove the significant increase in navigation performance by application of this concept. The generic mixed reality user interface together with robust local autonomy enables a further extension of the teleoperation system to a short-term predictive mixed reality user interface. With the presented concept of operation, it is possible to significantly reduce the visibility of system delays for the human operator. In addition, both advantageous characteristics of a 3D graphical user interface for robot teleoperation- an exocentric view and an augmented reality view – can be combined.
Within the healthcare environment, mobile health (mHealth) applications (apps) are becoming more and more important. The number of new mHealth apps has risen steadily in the last years. Especially the COVID-19 pandemic has led to an enormous amount of app releases. In most countries, mHealth applications have to be compliant with several regulatory aspects to be declared a “medical app”. However, the latest applicable medical device regulation (MDR) does not provide more details on the requirements for mHealth applications. When developing a medical app, it is essential that all contributors in an interdisciplinary team — especially software engineers — are aware of the specific regulatory requirements beforehand. The development process, however, should not be stalled due to integration of the MDR. Therefore, a developing framework that includes these aspects is required to facilitate a reliable and quick development process. The paper at hand introduces the creation of such a framework on the basis of the Corona Health and Corona Check apps. The relevant regulatory guidelines are listed and summarized as a guidance for medical app developments during the pandemic and beyond. In particular, the important stages and challenges faced that emerged during the entire development process are highlighted.
Overlapping is a common word used to describe documents whose structural dimensions cannot be adequately represented using tree structure. For instance a quotation that starts in one verse and ends in another verse. The problem of overlapping hierarchies is a recurring one, which has been addressed by a variety of approaches. There are XML based solutions as well as Non-XML ones. The XML-based solutions are: multiple documents, empty elements, fragmentation, out-of-line markup, JITT and BUVH. And the Non-XML approaches comprise CONCUR/XCONCUR, MECS, LMNL ...etc. This paper presents shortly state-of-the-art in overlapping hierarchies, and introduces two variations on the TEI fragmentation markup that have several advantages.
The first step towards aerial planetary exploration has been made. Ingenuity shows extremely promising results, and new missions are already underway. Rotorcraft are capable of flight. This capability could be utilized to support the last stages of Entry, Descent, and Landing. Thus, mass and complexity could be scaled down.
Autorotation is one method of descent. It describes unpowered descent and landing, typically performed by helicopters in case of an engine failure. MAPLE is suggested to test these procedures and understand autorotation on other planets. In this series of experiments, the Ingenuity helicopter is utilized. Ingenuity would autorotate a ”mid-air-landing” before continuing with normal flight. Ultimately, the collected data shall help to understand autorotation on Mars and its utilization for interplanetary exploration.
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.
LoRaWAN Network Planning in Smart Environments: Towards Reliability, Scalability, and Cost Reduction
(2022)
The goal in this work is to present a guidance for LoRaWAN planning to improve overall reliability for message transmissions and scalability. At the end, the cost component is discussed. Therefore, a five step approach is presented that helps to plan a LoRaWAN deployment step by step: Based on the device locations, an initial gateway placement is suggested followed by in-depth frequency and channel access planning. After an initial planning phase, updates for channel access and the initial gateway planning is suggested that should also be done periodically during network operation. Since current gateway placement approaches are only studied with random channel access, there is a lot of potential in the cell planning phase. Furthermore, the performance of different channel access approaches is highly related on network load, and thus cell size and sensor density. Last, the influence of different cell planning ideas on expected costs are discussed.
Social patterns and roles can develop when users talk to intelligent voice assistants (IVAs) daily. The current study investigates whether users assign different roles to devices and how this affects their usage behavior, user experience, and social perceptions. Since social roles take time to establish, we equipped 106 participants with Alexa or Google assistants and some smart home devices and observed their interactions for nine months. We analyzed diverse subjective (questionnaire) and objective data (interaction data). By combining social science and data science analyses, we identified two distinct clusters—users who assigned a friendship role to IVAs over time and users who did not. Interestingly, these clusters exhibited significant differences in their usage behavior, user experience, and social perceptions of the devices. For example, participants who assigned a role to IVAs attributed more friendship to them used them more frequently, reported more enjoyment during interactions, and perceived more empathy for IVAs. In addition, these users had distinct personal requirements, for example, they reported more loneliness. This study provides valuable insights into the role-specific effects and consequences of voice assistants. Recent developments in conversational language models such as ChatGPT suggest that the findings of this study could make an important contribution to the design of dialogic human–AI interactions.
A bipartite graph G=(U,V,E) is convex if the vertices in V can be linearly ordered such that for each vertex u∈U, the neighbors of u are consecutive in the ordering of V. An induced matching H of G is a matching for which no edge of E connects endpoints of two different edges of H. We show that in a convex bipartite graph with n vertices and m weighted edges, an induced matching of maximum total weight can be computed in O(n+m) time. An unweighted convex bipartite graph has a representation of size O(n) that records for each vertex u∈U the first and last neighbor in the ordering of V. Given such a compact representation, we compute an induced matching of maximum cardinality in O(n) time. In convex bipartite graphs, maximum-cardinality induced matchings are dual to minimum chain covers. A chain cover is a covering of the edge set by chain subgraphs, that is, subgraphs that do not contain induced matchings of more than one edge. Given a compact representation, we compute a representation of a minimum chain cover in O(n) time. If no compact representation is given, the cover can be computed in O(n+m) time. All of our algorithms achieve optimal linear running time for the respective problem and model, and they improve and generalize the previous results in several ways: The best algorithms for the unweighted problem versions had a running time of O(n\(^{2}\)) (Brandstädt et al. in Theor. Comput. Sci. 381(1–3):260–265, 2007. https://doi.org/10.1016/j.tcs.2007.04.006). The weighted case has not been considered before.
Digitization and transcription of historic documents offer new research opportunities for humanists and are the topics of many edition projects. However, manual work is still required for the main phases of layout recognition and the subsequent optical character recognition (OCR) of early printed documents. This paper describes and evaluates how deep learning approaches recognize text lines and can be extended to layout recognition using background knowledge. The evaluation was performed on five corpora of early prints from the 15th and 16th Centuries, representing a variety of layout features. While the main text with standard layouts could be recognized in the correct reading order with a precision and recall of up to 99.9%, also complex layouts were recognized at a rate as high as 90% by using background knowledge, the full potential of which was revealed if many pages of the same source were transcribed.
The holy grail of structural biology is to study a protein in situ, and this goal has been fast approaching since the resolution revolution and the achievement of atomic resolution. A cell's interior is not a dilute environment, and proteins have evolved to fold and function as needed in that environment; as such, an investigation of a cellular component should ideally include the full complexity of the cellular environment. Imaging whole cells in three dimensions using electron cryotomography is the best method to accomplish this goal, but it comes with a limitation on sample thickness and produces noisy data unamenable to direct analysis. This thesis establishes a novel workflow to systematically analyse whole-cell electron cryotomography data in three dimensions and to find and identify instances of protein complexes in the data to set up a determination of their structure and identity for success. Mycoplasma pneumoniae is a very small parasitic bacterium with fewer than 700 protein-coding genes, is thin enough and small enough to be imaged in large quantities by electron cryotomography, and can grow directly on the grids used for imaging, making it ideal for exploratory studies in structural proteomics. As part of the workflow, a methodology for training deep-learning-based particle-picking models is established.
As a proof of principle, a dataset of whole-cell Mycoplasma pneumoniae tomograms is used with this workflow to characterize a novel membrane-associated complex observed in the data. Ultimately, 25431 such particles are picked from 353 tomograms and refined to a density map with a resolution of 11 Å. Making good use of orthogonal datasets to filter search space and verify results, structures were predicted for candidate proteins and checked for suitable fit in the density map. In the end, with this approach, nine proteins were found to be part of the complex, which appears to be associated with chaperone activity and interact with translocon machinery.
Visual proteomics refers to the ultimate potential of in situ electron cryotomography: the comprehensive interpretation of tomograms. The workflow presented here is demonstrated to help in reaching that potential.
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.
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.
Knowledge encoding in game mechanics: transfer-oriented knowledge learning in desktop-3D and VR
(2019)
Affine Transformations (ATs) are a complex and abstract learning content. Encoding the AT knowledge in Game Mechanics (GMs) achieves a repetitive knowledge application and audiovisual demonstration. Playing a serious game providing these GMs leads to motivating and effective knowledge learning. Using immersive Virtual Reality (VR) has the potential to even further increase the serious game’s learning outcome and learning quality. This paper compares the effectiveness and efficiency of desktop-3D and VR in respect to the achieved learning outcome. Also, the present study analyzes the effectiveness of an enhanced audiovisual knowledge encoding and the provision of a debriefing system. The results validate the effectiveness of the knowledge encoding in GMs to achieve knowledge learning. The study also indicates that VR is beneficial for the overall learning quality and that an enhanced audiovisual encoding has only a limited effect on the learning outcome.
Though several previous studies reported the in vitro and in vivo antioxidant effect of kinetin (Kn), details on its action in cisplatin-induced toxicity are still scarce. In this study we evaluated, for the first time, the effects of kinetin in cisplatin (cp)- induced liver and lymphocyte toxicity in rats. Wistar male albino rats were divided into nine groups: (i) the control (C), (ii) groups 2,3 and 4, which received 0.25, 0.5 and 1 mg/kg kinetin for 10 days; (iii) the cisplatin (cp) group, which received a single intraperitoneal injection of CP (7.0 mg/kg); and (iv) groups 6, 7, 8 and 9, which received, for 10 days, 0.25, 0.5 and 1 mg/kg kinetin or 200 mg/kg vitamin C, respectively, and Cp on the fourth day. CP-injected rats showed a significant impairment in biochemical, oxidative stress and inflammatory parameters in hepatic tissue and lymphocytes. PCR showed a profound increase in caspase-3, and a significant decline in AKT gene expression. Intriguingly, Kn treatment restored the biochemical, redox status and inflammatory parameters. Hepatic AKT and caspase-3 expression as well as CD95 levels in lymphocytes were also restored. In conclusion, Kn mitigated oxidative imbalance, inflammation and apoptosis in CP-induced liver and lymphocyte toxicity; therefore, it can be considered as a promising therapy.