Institut für Informatik und Computational Science
Refine
Has Fulltext
- yes (245) (remove)
Year of publication
Document Type
- Article (116)
- Doctoral Thesis (85)
- Conference Proceeding (15)
- Master's Thesis (13)
- Postprint (10)
- Monograph/Edited Volume (2)
- Bachelor Thesis (1)
- Habilitation Thesis (1)
- Moving Images (1)
- Preprint (1)
Language
- English (126)
- German (118)
- Multiple languages (1)
Keywords
- Informatik (18)
- Didaktik (15)
- Hochschuldidaktik (14)
- Ausbildung (13)
- E-Learning (8)
- Maschinelles Lernen (7)
- Antwortmengenprogrammierung (6)
- Computer Science Education (5)
- Machine Learning (5)
- answer set programming (5)
- education (5)
- Informatikdidaktik (4)
- Modellierung (4)
- didactics (4)
- higher education (4)
- Answer Set Programming (3)
- Competence Measurement (3)
- DPLL (3)
- Digitalisierung (3)
- Komplexität (3)
- Ontologie (3)
- Secondary Education (3)
- Semantic Web (3)
- Softwareentwicklung (3)
- complexity (3)
- informatics (3)
- machine learning (3)
- Adaptivität (2)
- Algorithmen (2)
- Algorithms (2)
- Assessment (2)
- Autismus (2)
- Automatisches Beweisen (2)
- Big Data (2)
- Bildungstechnologien (2)
- Bildverarbeitung (2)
- Code (2)
- Competence Modelling (2)
- Computational thinking (2)
- Computer Science (2)
- Computergrafik (2)
- Computersicherheit (2)
- Constraint Solving (2)
- Coq (2)
- Data Privacy (2)
- Deduction (2)
- Digitale Medien (2)
- EEG (2)
- Educational Technologies (2)
- FMC (2)
- HCI (2)
- ICA (2)
- IT-Infrastruktur (2)
- Informatics (2)
- Informatics Education (2)
- Informatics Modelling (2)
- Informatics System Application (2)
- Informatics System Comprehension (2)
- Informatikstudium (2)
- Internet of Things (2)
- Key Competencies (2)
- Klausellernen (2)
- Knowledge Representation and Reasoning (2)
- Konstruktivismus (2)
- Künstliche Intelligenz (2)
- Lernumgebung (2)
- Logic Programming (2)
- Logics (2)
- MQTT (2)
- Mensch-Computer-Interaktion (2)
- Mensch-Technik-Interaktion (2)
- Methodik (2)
- Middleware (2)
- Modell (2)
- Onlinelehre (2)
- Ontology (2)
- Optimization (2)
- Planing (2)
- Prozessmodellierung (2)
- Relevanz (2)
- SAT (2)
- Software Engineering (2)
- Strategie (2)
- Synthese (2)
- Systemstruktur (2)
- Texturen (2)
- Theorembeweisen (2)
- Unifikation (2)
- User Experience (2)
- Visualisierung (2)
- Vorhersage (2)
- abstraction (2)
- code (2)
- computational thinking (2)
- computer graphics (2)
- computer science education (2)
- human computer interaction (2)
- image processing (2)
- maschinelles Lernen (2)
- model (2)
- non-photorealistic rendering (2)
- relevance (2)
- scientific workflows (2)
- secondary computer science education (2)
- software development (2)
- systems biology (2)
- teacher training (2)
- test (2)
- textures (2)
- theorem (2)
- virtual 3D city models (2)
- virtuelle 3D-Stadtmodelle (2)
- visualization (2)
- 'Peer To Peer' (1)
- 13C metabolic flux analysis (1)
- 21st century skills, (1)
- 3D Computer Grafik (1)
- 3D Computer Graphics (1)
- 3D Drucken (1)
- 3D Linsen (1)
- 3D Semiotik (1)
- 3D Visualisierung (1)
- 3D computer graphics (1)
- 3D lenses (1)
- 3D printing (1)
- 3D semiotics (1)
- 3D visualization (1)
- 3D-Stadtmodelle (1)
- 3d city models (1)
- 6LoWPAN (1)
- ABRACADABRA (1)
- ADFS (1)
- ARCS Modell (1)
- ASIC (1)
- ASIC (Applikationsspezifische Integrierte Schaltkreise) (1)
- ASP (Answer Set Programming) (1)
- Abbrecherquote (1)
- Abstraktion (1)
- Accepting Grammars (1)
- Access Datenbank (1)
- Achievement (1)
- Ackerschmalwand (1)
- Active Directory Federation Services (1)
- Active Evaluation (1)
- Activity Theory (1)
- Activity-orientated Learning (1)
- Adaptivity (1)
- Adversarial Learning (1)
- Aktive Evaluierung (1)
- Akzeptierende Grammatiken (1)
- Algorithmenablaufplanung (1)
- Algorithmenkonfiguration (1)
- Algorithmenselektion (1)
- Alignment (1)
- Angewandte Spieltheorie (1)
- Anisotroper Kuwahara Filter (1)
- Anleitung (1)
- Antwortmengen Programmierung (1)
- Application Aggregation (1)
- Applications and Software Development (1)
- Applied Game Theory (1)
- Arabidopsis thaliana (1)
- Arduino (1)
- Argumentation (1)
- Artificial Intelligence (1)
- Aspect-Oriented Programming (1)
- Aspektorientierte Programmierung (1)
- Asynchrone Schaltung (1)
- Attention (1)
- Audience Response Systeme (1)
- Aufmerksamkeit (1)
- Aufzählung (1)
- Augenbewegungen (1)
- Ausreissererkennung (1)
- Austria (1)
- Authentifizierung (1)
- Authorization (1)
- Autism (1)
- Automated Theorem Proving (1)
- Automatic Item Generation (1)
- Automatic UI Generation (1)
- Autorisierung (1)
- BCH (1)
- BCH code (1)
- BCH-Code (1)
- BCI (1)
- BSS (1)
- Bachelorstudierende der Informatik (1)
- Baumweite (1)
- Behavior (1)
- Benutzeroberfläche (1)
- Benutzungsschnittstellen Ontologien (1)
- Berührungseingaben (1)
- Betrachtungsebenen (1)
- Beweis (1)
- Beweisassistent (1)
- Beweistheorie (1)
- Beweisumgebung (1)
- Bilddatenanalyse (1)
- Bildung (1)
- Binäres Entscheidungsdiagramm (1)
- Bio-jETI (1)
- Biocomputing (1)
- Bioelektrisches Signal (1)
- Bioinformatik (1)
- Blended Learning (1)
- Bloom’s Taxonomy (1)
- Boolean constraint solver (1)
- Boosting (1)
- Brain Computer Interface (1)
- Business Process Models (1)
- CASP (Constraint Answer Set Programming) (1)
- CS concepts (1)
- CSC (1)
- Cactus (1)
- Capability approach (1)
- CertiCoq (1)
- Challenges (1)
- Choreographien (1)
- CityGML (1)
- Classification (1)
- Clause Learning (1)
- Cloud Computing (1)
- Cloud computing (1)
- Clusteranalyse (1)
- Codierung (1)
- Codierungstheorie (1)
- Coding theory (1)
- Cognitive Apprenticeship (1)
- Cognitive Skills (1)
- Common Spatial Pattern (1)
- Competences (1)
- Competencies (1)
- Complementary Circuits (1)
- Complexity (1)
- Compliance (1)
- Composed UIs (1)
- Composition (1)
- Computational Complexity (1)
- Computational Science (1)
- Computational Thinking (1)
- Computer Science in Context (1)
- Computergestützes Training (1)
- Computing (1)
- Conceptual (1)
- Constraint (1)
- Constraint-Programmierung (1)
- Constructive solid geometry (1)
- Contest (1)
- Contextualisation (1)
- Contradictions (1)
- Controlled Derivations (1)
- Covariate Shift (1)
- Curriculum (1)
- Curriculum Development (1)
- Curry (1)
- DDoS (1)
- DNA (1)
- DNA computing (1)
- DNS (1)
- Data Analysis (1)
- Data Management (1)
- Databases (1)
- Dateiformat (1)
- Datenschutz (1)
- Debugging (1)
- Deep Learning (1)
- Defining characteristics of physical computing (1)
- Dempster-Shafer-Theorie (1)
- Dempster–Shafer theory (1)
- Description Logics (1)
- Deskriptive Logik (1)
- Diagonalisierung (1)
- Dialog-based User Interfaces (1)
- Dialogbasierte Benutzerschnittstellen (1)
- Didaktik der Informatik (1)
- Didaktische Konzepte (1)
- Dienst-Ökosysteme (1)
- Dienstkomposition (1)
- Dienstplattform (1)
- Differenz von Gauss Filtern (1)
- Digital Competence (1)
- Digital Design (1)
- Digital Education (1)
- Digital Game Based Learning (1)
- Digital Media (1)
- Digital Revolution (1)
- Digitale Bibliothek (1)
- Digitalisation (1)
- Distributed Computing (1)
- Diversität (1)
- Dokument-Management-System (1)
- Domain-Specific Languages (1)
- Domänenspezifische Sprachen (1)
- Dreidimensionale Computergraphik (1)
- Dublin Core (1)
- Dynamic Programming (1)
- Dynamic assessment (1)
- Dynamische Programmierung (1)
- Dynamische Rekonfiguration (1)
- E-Assessment (1)
- E-Government (1)
- E-Klausuren (1)
- E-Portfolio (1)
- Early Literacy (1)
- Echtzeitanwendung (1)
- Educational Standards (1)
- Educational software (1)
- Eingabegenauigkeit (1)
- Eisenbahnnetz (1)
- Elektroencephalographie (1)
- Elektronisches Prüfen (1)
- Elektronisches Publizieren (1)
- Embedded Systems (1)
- Emotionen (1)
- Emotionsforschung (1)
- Enterprise Search (1)
- Entscheidungsbäume (1)
- Entwurf (1)
- Entwurfsmuster (1)
- Entwurfsmuster für SOA-Sicherheit (1)
- Entwurfsprinzipien (1)
- Entwurfsraumexploration (1)
- Equilibrium logic (1)
- Erfüllbarkeit einer Formel der Aussagenlogik (1)
- Erfüllbarkeitsproblem (1)
- Error Estimation (1)
- Error-Detection Circuits (1)
- Euclid’s algorithm (1)
- European Bioinformatics Institute (1)
- Evaluierung semantischer Suchmaschinen (1)
- Evidenztheorie (1)
- Exploration (1)
- Exponential Time Hypothesis (1)
- Exponentialzeit Hypothese (1)
- FMC-QE (1)
- FOSS (1)
- FPGA (1)
- Facebook (1)
- Feature Combination (1)
- Feedback (1)
- Fehlende Daten (1)
- Fehlererkennung (1)
- Fehlerkorrektur (1)
- Fehlerschätzung (1)
- Fehlvorstellung (1)
- Fibonacci numbers (1)
- Flussgesteuerter Bilateraler Filter (1)
- Focus+Context Visualization (1)
- Fokus-&-Kontext Visualisierung (1)
- Formalismus (1)
- Formalitätsgrad (1)
- Formeln der quantifizierten Aussagenlogik (1)
- Forschendes Lernen (1)
- Forschungsdatenmanagement (1)
- Function (1)
- Fundamental Ideas (1)
- GIS-Dienstkomposition (1)
- GPU (1)
- Game-Design-Elemente (1)
- Game-based learning (1)
- Gamification (1)
- Gebrauchstauglichkeit (1)
- Gebäudemodelle (1)
- Gehirn-Computer-Schnittstelle (1)
- Geländemodelle (1)
- Generalisierung (1)
- Generative Programmierung (1)
- Generative Programming (1)
- Geodaten (1)
- Geometrieerzeugung (1)
- Geovisualisierung (1)
- Geräte-Treiber (1)
- Geschäftsprozessmodelle (1)
- Gesichtsausdruck (1)
- Gesteuerte Ableitungen (1)
- Gleichheit (1)
- Globus (1)
- Grammar Systems (1)
- Grammatikalische Inferenz (1)
- Grammatiksysteme (1)
- Graph-basiertes Ranking (1)
- Graphensuche (1)
- Graphfärbung (1)
- Grid (1)
- Grid Computing (1)
- HDI (1)
- Hardware Design (1)
- Hardware-Software-Co-Design (1)
- Hauptkomponentenanalyse (1)
- Heterogenität (1)
- High-Level Synthesis (1)
- Hochschulbildung (1)
- Hochschullehre (1)
- Hochschulsystem (1)
- Human-Technology Interaction (1)
- I/O-effiziente Algorithmen (1)
- ICT (1)
- ICT Competence (1)
- ICT competencies (1)
- ICT skills (1)
- IP core (1)
- IT security (1)
- IT-Security (1)
- IT-Sicherheit (1)
- Informatik-Studiengänge (1)
- Informatiksystem (1)
- Informatikunterricht (1)
- Informatikvoraussetzungen (1)
- Information Retrieval (1)
- Information Transfer Rate (1)
- Informationsextraktion (1)
- Infrastruktur (1)
- Inkonsistenz (1)
- Innovation (1)
- Inquiry-based Learning (1)
- Inquiry-based learning (1)
- Integration (1)
- Interactive Rendering (1)
- Interactive system (1)
- Interaktionsmodel (1)
- Interaktionsmodellierung (1)
- Interaktionstechniken (1)
- Interaktives Rendering (1)
- Interaktives System (1)
- Interaktivität (1)
- Interface design (1)
- Internet Security (1)
- Internet applications (1)
- Internet-Sicherheit (1)
- Internetanwendungen (1)
- Interoperability (1)
- Interoperabilität (1)
- Intuition (1)
- IoT (1)
- Java Security Framework (1)
- Kartografisches Design (1)
- Kern-PCA (1)
- Kernmethoden (1)
- Klassifikation (1)
- Klassifikation mit großem Margin (1)
- Klassifikator-Kalibrierung (1)
- Klimafolgenanalyse (1)
- Klimawandel (1)
- Kommunikation (1)
- Kompetenz (1)
- Kompetenzerwerb (1)
- Kompilation (1)
- Komplexitätsbewältigung (1)
- Komplexitätstheorie (1)
- Komposition (1)
- Konnektionskalkül (1)
- Konzeptionell (1)
- Kryptographie (1)
- Kybernetik (1)
- LDPC code (1)
- LDPC-Code (1)
- LMS (1)
- Landmarken (1)
- Langzeitarchivierung (1)
- Large Margin Classification (1)
- Laser Cutten (1)
- Learners (1)
- Learning Analytics (1)
- Learning Fields (1)
- Learning ecology (1)
- Learning environment (1)
- Learning interfaces development (1)
- Learning with ICT (1)
- Lebenslanges Lernen (1)
- Leftmost Derivations (1)
- Lehrer (1)
- Lehrer*innenbildung (1)
- Lehrkräfteausbildung (1)
- Leistungsfähigkeit (1)
- Leistungsvorhersage (1)
- Lern-App (1)
- Lernaufgaben (1)
- Lernmotivation (1)
- Lernsoftware (1)
- Life-Long Learning (1)
- Liguistisch (1)
- Linked Data Anwendungen (1)
- Linked Data Application Modelling (1)
- Linksableitungen (1)
- Linux (1)
- Linux device drivers (1)
- Logarithm (1)
- Logik (1)
- Logikkalkül (1)
- Logiksynthese (1)
- Lower Bounds (1)
- Lower Secondary Level (1)
- MEG (1)
- MFA (1)
- MOOCs (1)
- Magnetoencephalographie (1)
- Malware (1)
- Massive Open Online Courses (1)
- Mathematical Optimization (1)
- Mathematikdidaktik (1)
- Mathematikphilosophie (1)
- Mathematische Optimierung (1)
- Matrizen-Eigenwertaufgabe (1)
- Measurement (1)
- Megamodel (1)
- Megamodell (1)
- Mehrklassen-Klassifikation (1)
- Message Passing Interface (1)
- Metamodell (1)
- Methoden der semantischen Suche (1)
- Methodology (1)
- Migration (1)
- Mischmodelle (1)
- Mischung <Signalverarbeitung> (1)
- Mobile App (1)
- Mobiles Lernen (1)
- Mobilgeräte (1)
- Model Based Engineering (1)
- Model Checking (1)
- Model Driven Architecture (1)
- Model Driven UI Development (1)
- Model Management (1)
- Model-Driven Engineering (1)
- Model-Driven Software Development (1)
- Modeling (1)
- Modell Management (1)
- Modell-driven Security (1)
- Modell-getriebene Sicherheit (1)
- Modellbasiert (1)
- Modellgetriebene Architektur (1)
- Modellgetriebene Entwicklung (1)
- Modellgetriebene Softwareentwicklung (1)
- Modellgetriebene UI Entwicklung (1)
- Modelling (1)
- Molekulare Bioinformatik (1)
- Motivation (1)
- Multi Task Learning (1)
- Multi-Class (1)
- Multi-Task-Lernen (1)
- Multimodal User Interfaces (1)
- Multimodale Benutzerschnittstellen (1)
- Multiprocessor (1)
- Multiprozessor (1)
- Music Technology (1)
- NETCONF (1)
- NUI (1)
- Natural Science Education (1)
- Navigation (1)
- Network Management (1)
- Netzwerk (1)
- Netzwerk Management (1)
- Netzwerke (1)
- Neuronales Netz (1)
- New On-Line Error-Detection Methode (1)
- Next Generation Network (1)
- Nicht-photorealistisches Rendering (1)
- Nichtfotorealistische Bildsynthese (1)
- NoSQL (1)
- Norway (1)
- Novice programmers (1)
- Nutzungserlebnis (1)
- Nutzungsinteresse (1)
- OAI-PMH (1)
- Objektive Schwierigkeit (1)
- Omega (1)
- Ontologien (1)
- Ontologies (1)
- Open Source (1)
- OpenOLAT (1)
- Optimierung (1)
- Optimierungsproblem (1)
- Owner-Retained Access Control (ORAC) (1)
- Parallel Programming (1)
- Parallele Datenverarbeitung (1)
- Paralleles Rechnen (1)
- Parallelrechner (1)
- Parameterized Complexity (1)
- Parametrisierte Komplexität (1)
- Parsing (1)
- Partizipation (1)
- Patterns (1)
- Pedagogical content knowledge (1)
- Peer-to-Peer-Netz ; GRID computing ; Zuverlässigkeit ; Web Services ; Betriebsmittelverwaltung ; Migration (1)
- Performance (1)
- Performance Prediction (1)
- Perl Formularskript (1)
- Persönliche Lernumgebung (1)
- Physical Science (1)
- Platzierung (1)
- Policy Enforcement (1)
- Policy Languages (1)
- Policy Sprachen (1)
- Power Monitoring (1)
- Pre-RS Traceability (1)
- Prediction Game (1)
- Predictive Models (1)
- Preprocessing (1)
- Problem Solving (1)
- Probleme in der Studie (1)
- Problemlösen (1)
- Process (1)
- Process modeling (1)
- Professoren (1)
- Programmierung (1)
- Proof Theory (1)
- Prototyp (1)
- Prototyping (1)
- Prozess (1)
- Prozess Verbesserung (1)
- Prozesse (1)
- Prozessmodell (1)
- Prozesssynchronisierung (1)
- Prädiktionsspiel (1)
- Präferenzen (1)
- Publikationsserver (1)
- Quantenkryptographie (1)
- Quantified Boolean Formula (QBF) (1)
- Quantitative Modeling (1)
- Quantitative Modellierung (1)
- Queuing Theory (1)
- Recommendations for CS-Curricula in Higher Education (1)
- Reconfigurable (1)
- Regression (1)
- Regularisierung (1)
- Regularization (1)
- Rekonfiguration (1)
- Rendering (1)
- Reparatur (1)
- Reuseable UIs (1)
- SMT (SAT Modulo Theories) (1)
- SOA Security Pattern (1)
- SSO (1)
- STG decomposition (1)
- STG-Dekomposition (1)
- Sample Selection Bias (1)
- Satisfiability (1)
- Scalability (1)
- Scene graph systems (1)
- Schlüsselkompetenzen (1)
- Schulmaterial (1)
- Security Modelling (1)
- Segmentierung (1)
- Selektion (1)
- Selektionsbias (1)
- Self-Checking Circuits (1)
- Semantic Search (1)
- Semantik Web (1)
- Semantische Suche (1)
- Sensornetzwerke (1)
- Sensors (1)
- Service Creation (1)
- Service Delivery Platform (1)
- Service Ecosystems (1)
- Service Oriented Architectures (1)
- Service convergence (1)
- Service-Orientierte Architekturen (1)
- Service-oriented Architectures (1)
- Serviceorientierte Architektur (1)
- Shader (1)
- Sicherheitsmodellierung (1)
- Signal Processing (1)
- Signalquellentrennung (1)
- Signaltrennung (1)
- Simultane Diagonalisierung (1)
- Single Event Transient (1)
- Single Sign On (1)
- Single Trial Analysis (1)
- Skalierbarkeit (1)
- Skelettberechnung (1)
- Small Private Online Courses (1)
- Social (1)
- Software (1)
- Software architecture (1)
- Software-basierte Cache-Kohärenz (1)
- Softwarearchitektur (1)
- Sonnenteilchen-Ereignis (1)
- Spam (1)
- Spam Filtering (1)
- Spam-Erkennung (1)
- Spam-Filter (1)
- Spam-Filtering (1)
- Spatio-Spectral Filter (1)
- Spawning (1)
- Spielbasiertes Lernen (1)
- Sprachdesign (1)
- Statistical Tests (1)
- Statistikprogramm R (1)
- Statistische Tests (1)
- Stilisierung (1)
- Strahlungshartes Design (1)
- Strahlungshärte Entwurf (1)
- Stromverbrauchüberwachung (1)
- Structuring (1)
- Strukturierung (1)
- Studentenerwartungen (1)
- Studentenhaltungen (1)
- Studentenjobs (1)
- Studienabbrecher (1)
- Studiendauer (1)
- Suche (1)
- Support Vectors (1)
- Support-Vector Lernen (1)
- System Biologie (1)
- System structure (1)
- Systembiologie (1)
- Systementwurf (1)
- Szenengraph (1)
- TPTP (1)
- Tailored UI Variants (1)
- Taktik (1)
- Tasks (1)
- Teacher perceptions (1)
- Teachers (1)
- Teaching information security (1)
- Technology proficiency (1)
- Telekommunikation (1)
- Temporal Logic (1)
- Temporallogik (1)
- Temporäre Anbindung (1)
- Terminologische Logik (1)
- Terminology (1)
- Test (1)
- Tests (1)
- Theoretische Informatik (1)
- Theoretischen Vorlesungen (1)
- Theory (1)
- Time Augmented Petri Nets (1)
- Time Series Analysis (1)
- Tool (1)
- Traceability (1)
- Tracking (1)
- Transformation (1)
- Treewidth (1)
- UI Components (1)
- UI Metamodels (1)
- UI-Komponenten (1)
- Unabhängige Komponentenanalyse (1)
- Universität Bagdad (1)
- Universität Potsdam (1)
- Universitätseinstellungen (1)
- Untere Schranken (1)
- Unterrichtswerkzeuge (1)
- Unvollständigkeit (1)
- Usability (1)
- Usage Interest (1)
- User Interface Ontologies (1)
- User Interfaces (1)
- VM (1)
- Verhalten (1)
- Verifikation (1)
- Verletzung Auflösung (1)
- Verletzung Erklärung (1)
- Verteiltes Rechnen (1)
- Verteilungsunterschied (1)
- Violation Explanation (1)
- Violation Resolution (1)
- Virtual Reality (1)
- Virtuelles 3D Stadtmodell (1)
- Vocational Education (1)
- Vorhersagemodelle (1)
- Wahrnehmung (1)
- Wahrnehmung von Arousal (1)
- Wahrnehmungsunterschiede (1)
- Warteschlangentheorie (1)
- Web Services (1)
- Web Sites (1)
- Web of Data (1)
- Webseite (1)
- Weiterbildung (1)
- Well-structuredness (1)
- Wetterextreme (1)
- Wirtschaftsinformatik (1)
- Wissenschaftlichesworkflows (1)
- Wissensrepräsentation und -verarbeitung (1)
- Wissensrepräsentation und Schlussfolgerung (1)
- Wohlstrukturiertheit (1)
- Workflow (1)
- Young People (1)
- ZQSA (1)
- ZQSAT (1)
- Zeitbehaftete Petri Netze (1)
- Zero-Suppressed Binary Decision Diagram (ZDD) (1)
- Zuverlässigkeitsanalyse (1)
- adaptiv (1)
- adaptive (1)
- algorithm configuration (1)
- algorithm scheduling (1)
- algorithm selection (1)
- analogical thinking (1)
- animated PCA (1)
- animierte PCA (1)
- anisotropic Kuwahara filter (1)
- anti-cancer drugs (1)
- approximate joint diagonalization (1)
- argument mining (1)
- argumentation (1)
- argumentation structure (1)
- arithmethische Prozeduren (1)
- arithmetic procedures (1)
- arousal perception (1)
- artificial intelligence (1)
- assistive Technologien (1)
- assistive technologies (1)
- asynchronous circuit (1)
- authentication (1)
- automated theorem proving (1)
- automatic feedback (1)
- automatic theorem prover (1)
- automatisierter Theorembeweiser (1)
- bild (1)
- binary representation (1)
- binary search (1)
- bio-computing (1)
- biometrics (1)
- biometrische Identifikation (1)
- blind source separation (1)
- building models (1)
- business informatics (1)
- cartographic design (1)
- changing the study field (1)
- changing the university (1)
- choreographies (1)
- classifier calibration (1)
- classroom language (1)
- classroom material (1)
- clause learning (1)
- climate change (1)
- climate impact analysis (1)
- clustering (1)
- cognitive apprenticeship (1)
- cognitive modifiability (1)
- coherence-enhancing filtering (1)
- communication (1)
- competence (1)
- competencies (1)
- competency (1)
- compilation (1)
- comprehension (1)
- computational biology (1)
- computational methods (1)
- computer science teachers (1)
- computer security (1)
- computergestützte Methoden (1)
- concurrent checking (1)
- connection calculus (1)
- constraint (1)
- constraint programming (1)
- constraints (1)
- constructivism (1)
- construktivism (1)
- cryptography (1)
- cs4fn (1)
- curriculum theory (1)
- debugging (1)
- decision trees (1)
- deep neural networks (1)
- degree of formality (1)
- design (1)
- design principles (1)
- design space exploration (1)
- didaktische Rekonstruktion (1)
- didaktisches Konzept (1)
- difference of Gaussians (1)
- digital circuit (1)
- digital design (1)
- digitale Bildung (1)
- digitale Hochschullehre (1)
- digitale Medien (1)
- digitally-enabled pedagogies (1)
- divide and conquer (1)
- dropout (1)
- drug-sensitivity prediction (1)
- dynamic (1)
- dynamic classification (1)
- dynamic reconfiguration (1)
- dynamisch (1)
- dynamische Klassifikation (1)
- e-Learning (1)
- e-mentoring (1)
- eGovernment (1)
- edge computing (1)
- education and public policy (1)
- educational programming (1)
- educational reconstruction (1)
- educational systems (1)
- edutainment (1)
- eingebettete Systeme (1)
- einseitige Kommunikation (1)
- email spam detection (1)
- embedded systems (1)
- emotion (1)
- emotion representation (1)
- emotion research (1)
- enterprise search (1)
- entity alignment (1)
- enumeration (1)
- environments (1)
- epistemic logic programs (1)
- epistemic specifications (1)
- equality (1)
- error correction (1)
- error detection (1)
- evidence theory (1)
- explicit negation (1)
- exponentiation (1)
- external memory algorithms (1)
- eye movements (1)
- face tracking (1)
- facial expression (1)
- firmware update (1)
- flow-based bilateral filter (1)
- formalism (1)
- freie Daten (1)
- freie Software (1)
- fun (1)
- game based learning (1)
- game design elements (1)
- game-based learning (1)
- generalization (1)
- geometry generation (1)
- geospatial data (1)
- geospatial services (1)
- geovisualization (1)
- global constraints (1)
- globale Constraints (1)
- grammar inference (1)
- graph clustering (1)
- graph-based ranking (1)
- graph-search (1)
- hardware design (1)
- hardware-software-codesign (1)
- high school (1)
- high-throughput analysis (1)
- higher (1)
- human-technology interaction (1)
- hybrid (1)
- hybrid semantic search (1)
- hybride semantische Suche (1)
- hybrides Problemlösen (1)
- image (1)
- image data analysis (1)
- incompleteness (1)
- inconsistency (1)
- independent component analysis (1)
- indirect economic impacts (1)
- indirekte ökonomische Effekte (1)
- informal and formal learning (1)
- informatics education (1)
- information extraction (1)
- information retrieval (1)
- informatische Bildung im Sekundarbereich (1)
- infrastructure (1)
- innovation (1)
- input accuracy (1)
- interaction modeling (1)
- interaction techniques (1)
- interactive course (1)
- interactive workshop (1)
- intuition (1)
- kernel PCA (1)
- kernel methods (1)
- key competences in physical computing (1)
- key competencies (1)
- kinaesthetic teaching (1)
- klinisch-praktischer Unterricht (1)
- konvergente Dienste (1)
- landmarks (1)
- language design (1)
- lautes Denken (1)
- leanCoP (1)
- learning (1)
- learning environment (1)
- lebenslanges Lernen (1)
- lesson planning (1)
- lesson preparation (1)
- linear code (1)
- linearer Code (1)
- linguistic (1)
- logic (1)
- logic programming (1)
- logic synthesis (1)
- logical calculus (1)
- logical errors (1)
- logical signaling networks (1)
- logische Ergänzung (1)
- logische Fehler (1)
- logische Programmierung (1)
- logische Signalnetzwerke (1)
- macro-economic modelling (1)
- makroökonomische Modellierung (1)
- malware detection (1)
- map/reduce (1)
- maschninelles Lernen (1)
- mathematics education (1)
- mediated learning experience (1)
- medical (1)
- medizinisch (1)
- meta model (1)
- methodology (1)
- middleware (1)
- misconception (1)
- mixture models (1)
- mobile devices (1)
- mobile learning (1)
- mobile technologies and apps (1)
- mobiles Lernen (1)
- mobiles lernen (1)
- model-based (1)
- model-driven architecture (1)
- modeling (1)
- molecular networks (1)
- molekulare Netzwerke (1)
- multi core data processing (1)
- multi-class classification (1)
- multiuser (1)
- navigation (1)
- network (1)
- networks (1)
- networks-on-chip (1)
- neue Online-Fehlererkennungsmethode (1)
- nichtlineare ICA (1)
- nichtlineare PCA (NLPCA) (1)
- nichtlineare Projektionen (1)
- non-monotonic reasoning (1)
- nonlinear ICA (1)
- nonlinear PCA (NLPCA) (1)
- nonlinear projections (1)
- objective difficulty (1)
- omega (1)
- on-chip (1)
- one-sided communication (1)
- oneM2M (1)
- online assistance (1)
- ontologies (1)
- open learning (1)
- open source (1)
- operating system (1)
- optimization (1)
- organisational evolution (1)
- outlier detection (1)
- output space compaction (1)
- overcomplete ICA (1)
- paper prototyping (1)
- parallel programming (1)
- parallel solving (1)
- parallele Programmierung (1)
- paralleles Lösen (1)
- parameter (1)
- parsing (1)
- pattern recognition (1)
- pedagogy (1)
- perception (1)
- perception differences (1)
- personal (1)
- personal response systems (1)
- philosophical foundation of informatics pedagogy (1)
- philosophy of mathematics (1)
- physical Computing (1)
- physical computing (1)
- physical computing tools (1)
- placement (1)
- policy evaluation (1)
- pre-primary level (1)
- prediction (1)
- preferences (1)
- preprocessing (1)
- primary education (1)
- primary level (1)
- priorities (1)
- probabilistic deep learning (1)
- probabilistic deep metric learning (1)
- probabilistische tiefe neuronale Netze (1)
- probabilistisches tiefes metrisches Lernen (1)
- problem-solving (1)
- process (1)
- process improvement (1)
- process model (1)
- process modelling (1)
- process synchronization (1)
- professional development (1)
- professors (1)
- programming (1)
- programming in context (1)
- proof (1)
- proof assistant (1)
- proof environment (1)
- propagation probability (1)
- prototype (1)
- proving (1)
- quantum cryptography (1)
- radiation hardness (1)
- radiation hardness design (1)
- railway network (1)
- real-time application (1)
- reconfiguration (1)
- rekonfigurierbar (1)
- reliability assessment (1)
- repair (1)
- robust ICA (1)
- robuste ICA (1)
- scheduling (1)
- search (1)
- secondary education (1)
- security (1)
- segmentation (1)
- selbstanpassendes Multiprozessorsystem (1)
- selbstprüfende Schaltungen (1)
- selection (1)
- self-adaptive multiprocessing system (1)
- self-efficacy (1)
- semantic domain modeling (1)
- semantic ranking (1)
- semantic search (1)
- semantic search evaluation (1)
- semantic search methods (1)
- semantische Domänenmodellierung (1)
- semantische Suche (1)
- semantisches Netz (1)
- semantisches Ranking (1)
- service composition (1)
- shader (1)
- sign language (1)
- single event upset (1)
- skeletonization (1)
- social media (1)
- socio-technical system (1)
- software (1)
- software engineering (1)
- software-based cache coherence (1)
- solar particle event (1)
- sozio-technisches System (1)
- speed independence (1)
- statistics program R (1)
- strahleninduzierte Einzelereignis-Effekte (1)
- structured output prediction (1)
- strukturierte Vorhersage (1)
- student activation (1)
- student experience (1)
- student perceptions (1)
- students’ conceptions (1)
- students’ knowledge (1)
- study problems (1)
- stylization (1)
- support system (1)
- synthesis (1)
- systematic (1)
- systematisch (1)
- tactic (1)
- teacher competencies (1)
- teachers (1)
- teaching informatics in general education (1)
- technische Rahmenbedingungen (1)
- temporary binding (1)
- terrain models (1)
- think aloud (1)
- tools (1)
- tools for teaching (1)
- topics (1)
- touch input (1)
- tptp (1)
- tracing (1)
- transformation (1)
- tutorial section (1)
- unification (1)
- university education (1)
- user interfaces (1)
- user-centred (1)
- verification (1)
- virtual 3D city model (1)
- virtual machine (1)
- virtual mobility (1)
- virtual reality (1)
- weather extremes (1)
- workflow management (1)
- zero-aliasing (1)
- überbestimmte ICA (1)
- ‘unplugged’ computing (1)
Institute
- Institut für Informatik und Computational Science (245)
- Hasso-Plattner-Institut für Digital Engineering gGmbH (18)
- Extern (6)
- eLiS - E-Learning in Studienbereichen (2)
- Historisches Institut (1)
- Potsdam Institute for Climate Impact Research (PIK) e. V. (1)
- Universitätsbibliothek (1)
- Wirtschaftswissenschaften (1)
- Zentrum für Qualitätsentwicklung in Lehre und Studium (ZfQ) (1)
This work introduces novel internal and external memory algorithms for computing voxel skeletons of massive voxel objects with complex network-like architecture and for converting these voxel skeletons to piecewise linear geometry, that is triangle meshes and piecewise straight lines. The presented techniques help to tackle the challenge of visualizing and analyzing 3d images of increasing size and complexity, which are becoming more and more important in, for example, biological and medical research. Section 2.3.1 contributes to the theoretical foundations of thinning algorithms with a discussion of homotopic thinning in the grid cell model. The grid cell model explicitly represents a cell complex built of faces, edges, and vertices shared between voxels. A characterization of pairs of cells to be deleted is much simpler than characterizations of simple voxels were before. The grid cell model resolves topologically unclear voxel configurations at junctions and locked voxel configurations causing, for example, interior voxels in sets of non-simple voxels. A general conclusion is that the grid cell model is superior to indecomposable voxels for algorithms that need detailed control of topology. Section 2.3.2 introduces a noise-insensitive measure based on the geodesic distance along the boundary to compute two-dimensional skeletons. The measure is able to retain thin object structures if they are geometrically important while ignoring noise on the object's boundary. This combination of properties is not known of other measures. The measure is also used to guide erosion in a thinning process from the boundary towards lines centered within plate-like structures. Geodesic distance based quantities seem to be well suited to robustly identify one- and two-dimensional skeletons. Chapter 6 applies the method to visualization of bone micro-architecture. Chapter 3 describes a novel geometry generation scheme for representing voxel skeletons, which retracts voxel skeletons to piecewise linear geometry per dual cube. The generated triangle meshes and graphs provide a link to geometry processing and efficient rendering of voxel skeletons. The scheme creates non-closed surfaces with boundaries, which contain fewer triangles than a representation of voxel skeletons using closed surfaces like small cubes or iso-surfaces. A conclusion is that thinking specifically about voxel skeleton configurations instead of generic voxel configurations helps to deal with the topological implications. The geometry generation is one foundation of the applications presented in Chapter 6. Chapter 5 presents a novel external memory algorithm for distance ordered homotopic thinning. The presented method extends known algorithms for computing chamfer distance transformations and thinning to execute I/O-efficiently when input is larger than the available main memory. The applied block-wise decomposition schemes are quite simple. Yet it was necessary to carefully analyze effects of block boundaries to devise globally correct external memory variants of known algorithms. In general, doing so is superior to naive block-wise processing ignoring boundary effects. Chapter 6 applies the algorithms in a novel method based on confocal microscopy for quantitative study of micro-vascular networks in the field of microcirculation.
An increasing number of applications requires user interfaces that facilitate the handling of large geodata sets. Using virtual 3D city models, complex geospatial information can be communicated visually in an intuitive way. Therefore, real-time visualization of virtual 3D city models represents a key functionality for interactive exploration, presentation, analysis, and manipulation of geospatial data. This thesis concentrates on the development and implementation of concepts and techniques for real-time city model visualization. It discusses rendering algorithms as well as complementary modeling concepts and interaction techniques. Particularly, the work introduces a new real-time rendering technique to handle city models of high complexity concerning texture size and number of textures. Such models are difficult to handle by current technology, primarily due to two problems: - Limited texture memory: The amount of simultaneously usable texture data is limited by the memory of the graphics hardware. - Limited number of textures: Using several thousand different textures simultaneously causes significant performance problems due to texture switch operations during rendering. The multiresolution texture atlases approach, introduced in this thesis, overcomes both problems. During rendering, it permanently maintains a small set of textures that are sufficient for the current view and the screen resolution available. The efficiency of multiresolution texture atlases is evaluated in performance tests. To summarize, the results demonstrate that the following goals have been achieved: - Real-time rendering becomes possible for 3D scenes whose amount of texture data exceeds the main memory capacity. - Overhead due to texture switches is kept permanently low, so that the number of different textures has no significant effect on the rendering frame rate. Furthermore, this thesis introduces two new approaches for real-time city model visualization that use textures as core visualization elements: - An approach for visualization of thematic information. - An approach for illustrative visualization of 3D city models. Both techniques demonstrate that multiresolution texture atlases provide a basic functionality for the development of new applications and systems in the domain of city model visualization.
The innovation of information techniques has changed many aspects of our life. In health care field, we can obtain, manage and communicate high-quality large volumetric image data by computer integrated devices, to support medical care. In this dissertation I propose several promising methods that could assist physicians in processing, observing and communicating the image data. They are included in my three research aspects: telemedicine integration, medical image visualization and image segmentation. And these methods are also demonstrated by the demo software that I developed. One of my research point focuses on medical information storage standard in telemedicine, for example DICOM, which is the predominant standard for the storage and communication of medical images. I propose a novel 3D image data storage method, which was lacking in current DICOM standard. I also created a mechanism to make use of the non-standard or private DICOM files. In this thesis I present several rendering techniques on medical image visualization to offer different display manners, both 2D and 3D, for example, cut through data volume in arbitrary degree, rendering the surface shell of the data, and rendering the semi-transparent volume of the data. A hybrid segmentation approach, designed for semi-automated segmentation of radiological image, such as CT, MRI, etc, is proposed in this thesis to get the organ or interested area from the image. This approach takes advantage of the region-based method and boundary-based methods. Three steps compose the hybrid approach: the first step gets coarse segmentation by fuzzy affinity and generates homogeneity operator; the second step divides the image by Voronoi Diagram and reclassifies the regions by the operator to refine segmentation from the previous step; the third step handles vague boundary by level set model. Topics for future research are mentioned in the end, including new supplement for DICOM standard for segmentation information storage, visualization of multimodal image information, and improvement of the segmentation approach to higher dimension.
Three quantum cryptographic protocols of multiuser quantum networks with embedded authentication, allowing quantum key distribution or quantum direct communication, are discussed in this work. The security of the protocols against different types of attacks is analysed with a focus on various impersonation attacks and the man-in-the-middle attack. On the basis of the security analyses several improvements are suggested and implemented in order to adjust the investigated vulnerabilities. Furthermore, the impact of the eavesdropping test procedure on impersonation attacks is outlined. The framework of a general eavesdropping test is proposed to provide additional protection against security risks in impersonation attacks.
Answer Set Programming (ASP) emerged in the late 1990s as a new logic programming paradigm, having its roots in nonmonotonic reasoning, deductive databases, and logic programming with negation as failure. The basic idea of ASP is to represent a computational problem as a logic program whose answer sets correspond to solutions, and then to use an answer set solver for finding answer sets of the program. ASP is particularly suited for solving NP-complete search problems. Among these, we find applications to product configuration, diagnosis, and graph-theoretical problems, e.g. finding Hamiltonian cycles. On different lines of ASP research, many extensions of the basic formalism have been proposed. The most intensively studied one is the modelling of preferences in ASP. They constitute a natural and effective way of selecting preferred solutions among a plethora of solutions for a problem. For example, preferences have been successfully used for timetabling, auctioning, and product configuration. In this thesis, we concentrate on preferences within answer set programming. Among several formalisms and semantics for preference handling in ASP, we concentrate on ordered logic programs with the underlying D-, W-, and B-semantics. In this setting, preferences are defined among rules of a logic program. They select preferred answer sets among (standard) answer sets of the underlying logic program. Up to now, those preferred answer sets have been computed either via a compilation method or by meta-interpretation. Hence, the question comes up, whether and how preferences can be integrated into an existing ASP solver. To solve this question, we develop an operational graph-based framework for the computation of answer sets of logic programs. Then, we integrate preferences into this operational approach. We empirically observe that our integrative approach performs in most cases better than the compilation method or meta-interpretation. Another research issue in ASP are optimization methods that remove redundancies, as also found in database query optimizers. For these purposes, the rather recently suggested notion of strong equivalence for ASP can be used. If a program is strongly equivalent to a subprogram of itself, then one can always use the subprogram instead of the original program, a technique which serves as an effective optimization method. Up to now, strong equivalence has not been considered for logic programs with preferences. In this thesis, we tackle this issue and generalize the notion of strong equivalence to ordered logic programs. We give necessary and sufficient conditions for the strong equivalence of two ordered logic programs. Furthermore, we provide program transformations for ordered logic programs and show in how far preferences can be simplified. Finally, we present two new applications for preferences within answer set programming. First, we define new procedures for group decision making, which we apply to the problem of scheduling a group meeting. As a second new application, we reconstruct a linguistic problem appearing in German dialects within ASP. Regarding linguistic studies, there is an ongoing debate about how unique the rule systems of language are in human cognition. The reconstruction of grammatical regularities with tools from computer science has consequences for this debate: if grammars can be modelled this way, then they share core properties with other non-linguistic rule systems.
Aufzählen von DNA-Codes
(2006)
In dieser Arbeit wird ein Modell zum Aufzählen von DNA-Codes entwickelt. Indem eine Ordnung auf der Menge aller DNA-Codewörter eingeführt und auf die Menge aller Codes erweitert wird, erlaubt das Modell das Auffinden von DNA-Codes mit bestimmten Eigenschaften, wie Überlappungsfreiheit, Konformität, Kommafreiheit, Stickyfreiheit, Überhangfreiheit, Teilwortkonformität und anderer bezüglich einer gegebenen Involution auf der Menge der Codewörter. Ein auf Grundlage des geschaffenen Modells entstandenes Werkzeug erlaubt das Suchen von Codes mit beliebigen Kombinationen von Codeeigenschaften. Ein weiterer wesentlicher Bestandteil dieser Arbeit ist die Untersuchung der Optimalität von DNA-Codes bezüglich ihrer Informationsrate sowie das Finden solider DNA-Codes.
Advances in biotechnologies rapidly increase the number of molecules of a cell which can be observed simultaneously. This includes expression levels of thousands or ten-thousands of genes as well as concentration levels of metabolites or proteins. Such Profile data, observed at different times or at different experimental conditions (e.g., heat or dry stress), show how the biological experiment is reflected on the molecular level. This information is helpful to understand the molecular behaviour and to identify molecules or combination of molecules that characterise specific biological condition (e.g., disease). This work shows the potentials of component extraction algorithms to identify the major factors which influenced the observed data. This can be the expected experimental factors such as the time or temperature as well as unexpected factors such as technical artefacts or even unknown biological behaviour. Extracting components means to reduce the very high-dimensional data to a small set of new variables termed components. Each component is a combination of all original variables. The classical approach for that purpose is the principal component analysis (PCA). It is shown that, in contrast to PCA which maximises the variance only, modern approaches such as independent component analysis (ICA) are more suitable for analysing molecular data. The condition of independence between components of ICA fits more naturally our assumption of individual (independent) factors which influence the data. This higher potential of ICA is demonstrated by a crossing experiment of the model plant Arabidopsis thaliana (Thale Cress). The experimental factors could be well identified and, in addition, ICA could even detect a technical artefact. However, in continuously observations such as in time experiments, the data show, in general, a nonlinear distribution. To analyse such nonlinear data, a nonlinear extension of PCA is used. This nonlinear PCA (NLPCA) is based on a neural network algorithm. The algorithm is adapted to be applicable to incomplete molecular data sets. Thus, it provides also the ability to estimate the missing data. The potential of nonlinear PCA to identify nonlinear factors is demonstrated by a cold stress experiment of Arabidopsis thaliana. The results of component analysis can be used to build a molecular network model. Since it includes functional dependencies it is termed functional network. Applied to the cold stress data, it is shown that functional networks are appropriate to visualise biological processes and thereby reveals molecular dynamics.
This thesis discusses challenges in IT security education, points out a gap between e-learning and practical education, and presents a work to fill the gap. E-learning is a flexible and personalized alternative to traditional education. Nonetheless, existing e-learning systems for IT security education have difficulties in delivering hands-on experience because of the lack of proximity. Laboratory environments and practical exercises are indispensable instruction tools to IT security education, but security education in conventional computer laboratories poses particular problems such as immobility as well as high creation and maintenance costs. Hence, there is a need to effectively transform security laboratories and practical exercises into e-learning forms. In this thesis, we introduce the Tele-Lab IT-Security architecture that allows students not only to learn IT security principles, but also to gain hands-on security experience by exercises in an online laboratory environment. In this architecture, virtual machines are used to provide safe user work environments instead of real computers. Thus, traditional laboratory environments can be cloned onto the Internet by software, which increases accessibility to laboratory resources and greatly reduces investment and maintenance costs. Under the Tele-Lab IT-Security framework, a set of technical solutions is also proposed to provide effective functionalities, reliability, security, and performance. The virtual machines with appropriate resource allocation, software installation, and system configurations are used to build lightweight security laboratories on a hosting computer. Reliability and availability of laboratory platforms are covered by a virtual machine management framework. This management framework provides necessary monitoring and administration services to detect and recover critical failures of virtual machines at run time. Considering the risk that virtual machines can be misused for compromising production networks, we present a security management solution to prevent the misuse of laboratory resources by security isolation at the system and network levels. This work is an attempt to bridge the gap between e-learning/tele-teaching and practical IT security education. It is not to substitute conventional teaching in laboratories but to add practical features to e-learning. This thesis demonstrates the possibility to implement hands-on security laboratories on the Internet reliably, securely, and economically.
With increasing number of applications in Internet and mobile environments, distributed software systems are demanded to be more powerful and flexible, especially in terms of dynamism and security. This dissertation describes my work concerning three aspects: dynamic reconfiguration of component software, security control on middleware applications, and web services dynamic composition. Firstly, I proposed a technology named Routing Based Workflow (RBW) to model the execution and management of collaborative components and realize temporary binding for component instances. The temporary binding means component instances are temporarily loaded into a created execution environment to execute their functions, and then are released to their repository after executions. The temporary binding allows to create an idle execution environment for all collaborative components, on which the change operations can be immediately carried out. The changes on execution environment will result in a new collaboration of all involved components, and also greatly simplifies the classical issues arising from dynamic changes, such as consistency preserving etc. To demonstrate the feasibility of RBW, I created a dynamic secure middleware system - the Smart Data Server Version 3.0 (SDS3). In SDS3, an open source implementation of CORBA is adopted and modified as the communication infrastructure, and three secure components managed by RBW, are created to enhance the security on the access of deployed applications. SDS3 offers multi-level security control on its applications from strategy control to application-specific detail control. For the management by RBW, the strategy control of SDS3 applications could be dynamically changed by reorganizing the collaboration of the three secure components. In addition, I created the Dynamic Services Composer (DSC) based on Apache open source projects, Apache Axis and WSIF. In DSC, RBW is employed to model the interaction and collaboration of web services and to enable the dynamic changes on the flow structure of web services. Finally, overall performance tests were made to evaluate the efficiency of the developed RBW and SDS3. The results demonstrated that temporary binding of component instances makes slight impacts on the execution efficiency of components, and the blackout time arising from dynamic changes can be extremely reduced in any applications.
The goal of a Brain-Computer Interface (BCI) consists of the development of a unidirectional interface between a human and a computer to allow control of a device only via brain signals. While the BCI systems of almost all other groups require the user to be trained over several weeks or even months, the group of Prof. Dr. Klaus-Robert Müller in Berlin and Potsdam, which I belong to, was one of the first research groups in this field which used machine learning techniques on a large scale. The adaptivity of the processing system to the individual brain patterns of the subject confers huge advantages for the user. Thus BCI research is considered a hot topic in machine learning and computer science. It requires interdisciplinary cooperation between disparate fields such as neuroscience, since only by combining machine learning and signal processing techniques based on neurophysiological knowledge will the largest progress be made. In this work I particularly deal with my part of this project, which lies mainly in the area of computer science. I have considered the following three main points: <b>Establishing a performance measure based on information theory:</b> I have critically illuminated the assumptions of Shannon's information transfer rate for application in a BCI context. By establishing suitable coding strategies I was able to show that this theoretical measure approximates quite well to what is practically achieveable. <b>Transfer and development of suitable signal processing and machine learning techniques:</b> One substantial component of my work was to develop several machine learning and signal processing algorithms to improve the efficiency of a BCI. Based on the neurophysiological knowledge that several independent EEG features can be observed for some mental states, I have developed a method for combining different and maybe independent features which improved performance. In some cases the performance of the combination algorithm outperforms the best single performance by more than 50 %. Furthermore, I have theoretically and practically addressed via the development of suitable algorithms the question of the optimal number of classes which should be used for a BCI. It transpired that with BCI performances reported so far, three or four different mental states are optimal. For another extension I have combined ideas from signal processing with those of machine learning since a high gain can be achieved if the temporal filtering, i.e., the choice of frequency bands, is automatically adapted to each subject individually. <b>Implementation of the Berlin brain computer interface and realization of suitable experiments:</b> Finally a further substantial component of my work was to realize an online BCI system which includes the developed methods, but is also flexible enough to allow the simple realization of new algorithms and ideas. So far, bitrates of up to 40 bits per minute have been achieved with this system by absolutely untrained users which, compared to results of other groups, is highly successful.
Modern biological analysis techniques supply scientists with various forms of data. One category of such data are the so called "expression data". These data indicate the quantities of biochemical compounds present in tissue samples. Recently, expression data can be generated at a high speed. This leads in turn to amounts of data no longer analysable by classical statistical techniques. Systems biology is the new field that focuses on the modelling of this information. At present, various methods are used for this purpose. One superordinate class of these methods is machine learning. Methods of this kind had, until recently, predominantly been used for classification and prediction tasks. This neglected a powerful secondary benefit: the ability to induce interpretable models. Obtaining such models from data has become a key issue within Systems biology. Numerous approaches have been proposed and intensively discussed. This thesis focuses on the examination and exploitation of one basic technique: decision trees. The concept of comparing sets of decision trees is developed. This method offers the possibility of identifying significant thresholds in continuous or discrete valued attributes through their corresponding set of decision trees. Finding significant thresholds in attributes is a means of identifying states in living organisms. Knowing about states is an invaluable clue to the understanding of dynamic processes in organisms. Applied to metabolite concentration data, the proposed method was able to identify states which were not found with conventional techniques for threshold extraction. A second approach exploits the structure of sets of decision trees for the discovery of combinatorial dependencies between attributes. Previous work on this issue has focused either on expensive computational methods or the interpretation of single decision trees a very limited exploitation of the data. This has led to incomplete or unstable results. That is why a new method is developed that uses sets of decision trees to overcome these limitations. Both the introduced methods are available as software tools. They can be applied consecutively or separately. That way they make up a package of analytical tools that usefully supplement existing methods. By means of these tools, the newly introduced methods were able to confirm existing knowledge and to suggest interesting and new relationships between metabolites.
Quantified Boolean formulas (QBFs) play an important role in theoretical computer science. QBF extends propositional logic in such a way that many advanced forms of reasoning can be easily formulated and evaluated. In this dissertation we present our ZQSAT, which is an algorithm for evaluating quantified Boolean formulas. ZQSAT is based on ZBDD: Zero-Suppressed Binary Decision Diagram , which is a variant of BDD, and an adopted version of the DPLL algorithm. It has been implemented in C using the CUDD: Colorado University Decision Diagram package. The capability of ZBDDs in storing sets of subsets efficiently enabled us to store the clauses of a QBF very compactly and let us to embed the notion of memoization to the DPLL algorithm. These points led us to implement the search algorithm in such a way that we could store and reuse the results of all previously solved subformulas with a little overheads. ZQSAT can solve some sets of standard QBF benchmark problems (known to be hard for DPLL based algorithms) faster than the best existing solvers. In addition to prenex-CNF, ZQSAT accepts prenex-NNF formulas. We show and prove how this capability can be exponentially beneficial.
Thema dieser Arbeit sind echtzeitfähige 3D-Renderingverfahren, die 3D-Geometrie mit über der Standarddarstellung hinausgehenden Qualitäts- und Gestaltungsmerkmalen rendern können. Beispiele sind Verfahren zur Darstellung von Schatten, Reflexionen oder Transparenz. Mit heutigen computergraphischen Software-Basissystemen ist ihre Integration in 3D-Anwendungssysteme sehr aufwändig: Dies liegt einerseits an der technischen, algorithmischen Komplexität der Einzelverfahren, andererseits an Ressourcenkonflikten und Seiteneffekten bei der Kombination mehrerer Verfahren. Szenengraphsysteme, intendiert als computergraphische Softwareschicht zur Abstraktion von der Graphikhardware, stellen derzeit keine Mechanismen zur Nutzung dieser Renderingverfahren zur Verfügung. Ziel dieser Arbeit ist es, eine Software-Architektur für ein Szenengraphsystem zu konzipieren und umzusetzen, die echtzeitfähige 3D-Renderingverfahren als Komponenten modelliert und es damit erlaubt, diese Verfahren innerhalb des Szenengraphsystems für die Anwendungsentwicklung effektiv zu nutzen. Ein Entwickler, der ein solches Szenengraphsystem nutzt, steuert diese Komponenten durch Elemente in der Szenenbeschreibung an, die die sichtbare Wirkung eines Renderingverfahrens auf die Geometrie in der Szene angeben, aber keine Hinweise auf die algorithmische Implementierung des Verfahrens enthalten. Damit werden Renderingverfahren in 3D-Anwendungssystemen nutzbar, ohne dass ein Entwickler detaillierte Kenntnisse über sie benötigt, so dass der Aufwand für ihre Entwicklung drastisch reduziert wird. Ein besonderer Augenmerk der Arbeit liegt darauf, auf diese Weise auch verschiedene Renderingverfahren in einer Szene kombiniert einsetzen zu können. Hierzu ist eine Unterteilung der Renderingverfahren in mehrere Kategorien erforderlich, die mit Hilfe unterschiedlicher Ansätze ausgewertet werden. Dies erlaubt die Abstimmung verschiedener Komponenten für Renderingverfahren und ihrer verwendeten Ressourcen. Die Zusammenarbeit mehrerer Renderingverfahren hat dort ihre Grenzen, wo die Kombination von Renderingverfahren graphisch nicht sinnvoll ist oder fundamentale technische Beschränkungen der Verfahren eine gleichzeitige Verwendung unmöglich machen. Die in dieser Arbeit vorgestellte Software-Architektur kann diese Grenzen nicht verschieben, aber sie ermöglicht den gleichzeitigen Einsatz vieler Verfahren, bei denen eine Kombination aufgrund der hohen Komplexität der Implementierung bislang nicht erreicht wurde. Das Vermögen zur Zusammenarbeit ist dabei allerdings von der Art eines Einzelverfahrens abhängig: Verfahren zur Darstellung transparenter Geometrie beispielsweise erfordern bei der Kombination mit anderen Verfahren in der Regel vollständig neuentwickelte Renderingverfahren; entsprechende Komponenten für das Szenengraphsystem können daher nur eingeschränkt mit Komponenten für andere Renderingverfahren verwendet werden. Das in dieser Arbeit entwickelte System integriert und kombiniert Verfahren zur Darstellung von Bumpmapping, verschiedene Schatten- und Reflexionsverfahren sowie bildbasiertes CSG-Rendering. Damit stehen wesentliche Renderingverfahren in einem Szenengraphsystem erstmalig komponentenbasiert und auf einem hohen Abstraktionsniveau zur Verfügung. Das System ist trotz des zusätzlichen Verwaltungsaufwandes in der Lage, die Renderingverfahren einzeln und in Kombination grundsätzlich in Echtzeit auszuführen.
Mit zunehmender Komplexität technischer Softwaresysteme ist die Nachfrage an produktiveren Methoden und Werkzeugen auch im sicherheitskritischen Umfeld gewachsen. Da insbesondere objektorientierte und modellbasierte Ansätze und Methoden ausgezeichnete Eigenschaften zur Entwicklung großer und komplexer Systeme besitzen, ist zu erwarten, dass diese in naher Zukunft selbst bis in sicherheitskritische Bereiche der Softwareentwicklung vordringen. Mit der Unified Modeling Language Real-Time (UML-RT) wird eine Softwareentwicklungsmethode für technische Systeme durch die Object Management Group (OMG) propagiert. Für den praktischen Einsatz im technischen und sicherheitskritischen Umfeld muss diese Methode nicht nur bestimmte technische Eigenschaften, beispielsweise temporale Analysierbarkeit, besitzen, sondern auch in einen bestehenden Qualitätssicherungsprozess integrierbar sein. Ein wichtiger Aspekt der Integration der UML-RT in ein qualitätsorientiertes Prozessmodell, beispielsweise in das V-Modell, ist die Verfügbarkeit von ausgereiften Konzepten und Methoden für einen systematischen Modultest. Der Modultest dient als erste Qualititätssicherungsphase nach der Implementierung der Fehlerfindung und dem Qualitätsnachweis für jede separat prüfbare Softwarekomponente eines Systems. Während dieser Phase stellt die Durchführung von systematischen Tests die wichtigste Qualitätssicherungsmaßnahme dar. Während zum jetzigen Zeitpunkt zwar ausgereifte Methoden und Werkzeuge für die modellbasierte Softwareentwicklung zur Verfügung stehen, existieren nur wenig überzeugende Lösungen für eine systematische modellbasierte Modulprüfung. Die durchgängige Verwendung ausführbarer Modelle und Codegenerierung stellen wesentliche Konzepte der modellbasierten Softwareentwicklung dar. Sie dienen der konstruktiven Fehlerreduktion durch Automatisierung ansonsten fehlerträchtiger, manueller Vorgänge. Im Rahmen einer modellbasierten Qualitätssicherung sollten diese Konzepte konsequenterweise in die späteren Qualitätssicherungsphasen transportiert werden. Daher ist eine wesentliche Forderung an ein Verfahren zur modellbasierten Modulprüfung ein möglichst hoher Grad an Automatisierung. In aktuellen Entwicklungen hat sich für die Generierung von Testfällen auf Basis von Zustandsautomaten die Verwendung von Model Checking als effiziente und an die vielfältigsten Testprobleme anpassbare Methode bewährt. Der Ansatz des Model Checking stammt ursprünglich aus dem Entwurf von Kommunikationsprotokollen und wurde bereits erfolgreich auf verschiedene Probleme der Modellierung technischer Software angewendet. Insbesondere in der Gegenwart ausführbarer, automatenbasierter Modelle erscheint die Verwendung von Model Checking sinnvoll, das die Existenz einer formalen, zustandsbasierten Spezifikation voraussetzt. Ein ausführbares, zustandsbasiertes Modell erfüllt diese Anforderungen in der Regel. Aus diesen Gründen ist die Wahl eines Model Checking Ansatzes für die Generierung von Testfällen im Rahmen eines modellbasierten Modultestverfahrens eine logische Konsequenz. Obwohl in der aktuellen Spezifikation der UML-RT keine eindeutigen Aussagen über den zur Verhaltensbeschreibung zu verwendenden Formalismus gemacht werden, ist es wahrscheinlich, dass es sich bei der UML-RT um eine zu Real-Time Object-Oriented Modeling (ROOM) kompatible Methode handelt. Alle in dieser Arbeit präsentierten Methoden und Ergebnisse sind somit auf die kommende UML-RT übertragbar und von sehr aktueller Bedeutung. Aus den genannten Gründen verfolgt diese Arbeit das Ziel, die analytische Qualitätssicherung in der modellbasierten Softwareentwicklung mittels einer modellbasierten Methode für den Modultest zu verbessern. Zu diesem Zweck wird eine neuartige Testmethode präsentiert, die auf automatenbasierten Verhaltensmodellen und CTL Model Checking basiert. Die Testfallgenerierung kann weitgehend automatisch erfolgen, um Fehler durch menschlichen Einfluss auszuschließen. Das entwickelte Modultestverfahren ist in die technischen Konzepte Model Driven Architecture und ROOM, beziehungsweise UML-RT, sowie in die organisatorischen Konzepte eines qualitätsorientierten Prozessmodells, beispielsweise das V-Modell, integrierbar.
Entwickelt wird ein Dokument Management System zur elektronischen, Client-Server-basierten Publikation und Langzeitarchivierung von Hochschulschriften für die Universitätsbibliothek Potsdam. Der zu konzipierende Dokumentenserver muss den bibliothekarischen Anforderungen im Hinblick auf die Sicherung von Authentizität und Integrität des Servers und der einzelnen Textdokumente entsprechen. Eine Analyse der Eignung verbreiteter Dateiformate zur dauerhaften Speicherung unter Berücksichtigung von Verfügbarkeit, Strukturierbarkeit, Konvertierbarkeit und Austauschbarkeit sowie Recherchierbarkeit erbringt eine langfristig anzustrebende Präferenz für XML als Archivierungs- und Rechercheformat sowie PDF und/oder HTML als Präsentationsformate. Die Formalerfassung erfolgt über die Anreicherung des Dokumentes mit Metadaten nach dem DC qualified Standard, die in einer Datenbank strukturiert abgelegt sind. Der dauerhafte Zugang zur Publikation kann durch Verwendung einer zitierfähigen URN (Persistent Identifier) gesichert werden. Bestehende Archivierungssysteme werden untersucht und auf Vereinbarkeit mit den lokalen Bedürfnissen geprüft. Ein Workflow für die Anlieferung von Dokument und beschreibenden Metadaten durch den Autor und die weitere Bearbeitung durch die Bibliothek wird erarbeitet und die technische Umsetzung mittels Perl, HTML, XML und einer MS Access Datenbank beschrieben. Der Dokumentenserver ermöglicht performantes Retrieval und ist als Dataprovider mit einer OAI-Schnittstelle für den weltweiten, standardisierten Datenaustausch ausgestattet. Das System kann in wissenschaftlichen Informationseinrichtungen als Internet- oder Intranet-Repositorium eingesetzt werden. (Fremdreferat)
This thesis is concerned with the solution of the blind source separation problem (BSS). The BSS problem occurs frequently in various scientific and technical applications. In essence, it consists in separating meaningful underlying components out of a mixture of a multitude of superimposed signals. In the recent research literature there are two related approaches to the BSS problem: The first is known as Independent Component Analysis (ICA), where the goal is to transform the data such that the components become as independent as possible. The second is based on the notion of diagonality of certain characteristic matrices derived from the data. Here the goal is to transform the matrices such that they become as diagonal as possible. In this thesis we study the latter method of approximate joint diagonalization (AJD) to achieve a solution of the BSS problem. After an introduction to the general setting, the thesis provides an overview on particular choices for the set of target matrices that can be used for BSS by joint diagonalization. As the main contribution of the thesis, new algorithms for approximate joint diagonalization of several matrices with non-orthogonal transformations are developed. These newly developed algorithms will be tested on synthetic benchmark datasets and compared to other previous diagonalization algorithms. Applications of the BSS methods to biomedical signal processing are discussed and exemplified with real-life data sets of multi-channel biomagnetic recordings.
Die Dissertation stellt eine neue Herangehensweise an die Lösung der Aufgabe der funktionalen Diagnostik digitaler Systeme vor. In dieser Arbeit wird eine neue Methode für die Fehlererkennung vorgeschlagen, basierend auf der Logischen Ergänzung und der Verwendung von Berger-Codes und dem 1-aus-3 Code. Die neue Fehlererkennungsmethode der Logischen Ergänzung gestattet einen hohen Optimierungsgrad der benötigten Realisationsfläche der konstruierten Fehlererkennungsschaltungen. Außerdem ist eins der wichtigen in dieser Dissertation gelösten Probleme die Synthese vollständig selbstprüfender Schaltungen.
Interaktive System sind dynamische Systeme mit einem zumeist informationellen Kern, die über eine Benutzungsschnittstelle von einem oder mehreren Benutzern bedient werden können. Grundlage für die Benutzung interaktiver Systeme ist das Verständnis von Zweck und Funktionsweise. Allein aus Form und Gestalt der Benutzungsschnittstelle ergibt sich ein solches Verständnis nur in einfachen Fällen. Mit steigender Komplexität ist daher eine verständliche Beschreibung solcher Systeme für deren Entwicklung und Benutzung unverzichtbar. Abhängig von ihrem Zweck variieren die Formen vorgefundener Beschreibungen in der Literatur sehr stark. Ausschlaggebend für die Verständlichkeit einer Beschreibung ist jedoch primär die ihr zugrundeliegende Begriffswelt. Zur Beschreibung allgemeiner komplexer diskreter Systeme - aufbauend auf einer getrennten Betrachtung von Aufbau-, Ablauf- und Wertestrukturen - existiert eine bewährte Begriffswelt. Eine Spezialisierung dieser Begriffs- und Vorstellungswelt, die den unterschiedlichen Betrachtungsebenen interaktiver Systeme gerecht wird und die als Grundlage beliebiger Beschreibungsansätze interaktiver Systeme dienen kann, gibt es bisher nicht. Ziel dieser Arbeit ist die Bereitstellung einer solchen Begriffswelt zur effizienten Kommunikation der Strukturen interaktiver Systeme. Dadurch soll die Grundlage für eine sinnvolle Ergänzung bestehender Beschreibungs- und Entwicklungsansätze geschaffen werden. Prinzipien der Gestaltung von Benutzungsschnittstellen, Usability- oder Ergonomiebetrachtungen stehen nicht im Mittelpunkt der Arbeit. Ausgehend von der informationellen Komponente einer Benutzungsschnittstelle werden drei Modellebenen abgegrenzt, die bei der Betrachtung eines interaktiven Systems zu unterscheiden sind. Jede Modellebene ist durch eine typische Begriffswelt gekennzeichnet, die ihren Ursprung in einer aufbauverwurzelten Vorstellung hat. Der durchgängige Bezug auf eine Systemvorstellung unterscheidet diesen Ansatz von dem bereits bekannten Konzept der Abgrenzung unterschiedlicher Ebenen verschiedenartiger Entwurfsentscheidungen. Die Fundamental Modeling Concepts (FMC) bilden dabei die Grundlage für die Findung und die Darstellung von Systemstrukturen. Anhand bestehender Systembeschreibungen wird gezeigt, wie die vorgestellte Begriffswelt zur Modellfindung genutzt werden kann. Dazu wird eine repräsentative Auswahl vorgefundener Systembeschreibungen aus der einschlägigen Literatur daraufhin untersucht, in welchem Umfang durch sie die Vorstellungswelt dynamischer Systeme zum Ausdruck kommt. Defizite in der ursprünglichen Darstellung werden identifiziert. Anhand von Alternativmodellen zu den betrachteten Systemen wird der Nutzen der vorgestellten Begriffswelt und Darstellungsweise demonstriert.
Zur Beherrschung großer Systeme, insbesondere zur Weitergabe und Nutzung von Erfahrungswissen in der frühen Entwurfs- und Planungsphase, benötigt man Abstraktionen für deren Strukturen. Trennt man Software- von Systemstrukturen, kann man mit letzteren Systeme auf ausreichend hohem Abstraktionsgrad beschreiben.Software-Patterns dienen dazu, Erfahrungswissen bezüglich programmierter Systeme strukturiert weiterzugeben. Dabei wird unterschieden zwischen Idiomen, die sich auf Lösungen mit einer bestimmten Programmiersprache beziehen, Design-Patterns, die nur einen kleinen Teil des Programms betreffen und Architektur-Patterns, deren Einfluss über einen größeren Teil oder gar das komplette Programm reicht. Eine Untersuchung von existierenden Patterns zeigt, dass deren Konzepte nützlich zum Finden von Systemstrukturen sind. Die grafische Darstellung dieser Patterns ist dagegen oft auf Software-Strukturen eingeschränkt und ist für die Vermittlung von Erfahrungen zum Finden von Systemstrukturen meist nicht geeignet. Daher wird die Kategorie der konzeptionellen Patterns mit einer darauf abgestimmten grafischen Darstellungsform vorgeschlagen, bei denen Problem und Lösungsvorschlag im Bereich der Systemstrukturen liegen. Sie betreffen informationelle Systeme, sind aber nicht auf Lösungen mit Software beschränkt. Die Systemstrukturen werden grafisch dargestellt, wobei dafür die Fundamental Modeling Concepts (FMC) verwendet werden, die zur Darstellung von Systemstrukturen entwickelt wurden.
Independent component analysis (ICA) is a tool for statistical data analysis and signal processing that is able to decompose multivariate signals into their underlying source components. Although the classical ICA model is highly useful, there are many real-world applications that require powerful extensions of ICA. This thesis presents new methods that extend the functionality of ICA: (1) reliability and grouping of independent components with noise injection, (2) robust and overcomplete ICA with inlier detection, and (3) nonlinear ICA with kernel methods.