Institut für Informatik und Computational Science
Refine
Has Fulltext
- yes (125) (remove)
Year of publication
Document Type
- Doctoral Thesis (64)
- Article (40)
- Postprint (10)
- Conference Proceeding (5)
- Master's Thesis (3)
- Bachelor Thesis (1)
- Habilitation Thesis (1)
- Preprint (1)
Language
- English (125) (remove)
Keywords
- Maschinelles Lernen (7)
- Antwortmengenprogrammierung (5)
- Computer Science Education (5)
- Machine Learning (5)
- answer set programming (4)
- Answer Set Programming (3)
- Competence Measurement (3)
- DPLL (3)
- Secondary Education (3)
- machine learning (3)
- Algorithmen (2)
- Algorithms (2)
- Automatisches Beweisen (2)
- Big Data (2)
- Competence Modelling (2)
- Computational thinking (2)
- Computer Science (2)
- Computersicherheit (2)
- Constraint Solving (2)
- Data Privacy (2)
- Deduction (2)
- EEG (2)
- HCI (2)
- ICA (2)
- Informatics (2)
- Informatics Education (2)
- Informatics Modelling (2)
- Informatics System Application (2)
- Informatics System Comprehension (2)
- Informatik (2)
- Internet of Things (2)
- Key Competencies (2)
- Klausellernen (2)
- Knowledge Representation and Reasoning (2)
- Künstliche Intelligenz (2)
- Logic Programming (2)
- Logics (2)
- MQTT (2)
- Middleware (2)
- Modell (2)
- Ontologie (2)
- Optimization (2)
- Planing (2)
- Relevanz (2)
- SAT (2)
- Semantic Web (2)
- Theorembeweisen (2)
- Unifikation (2)
- Vorhersage (2)
- abstraction (2)
- complexity (2)
- computational thinking (2)
- computer science education (2)
- education (2)
- higher education (2)
- maschinelles Lernen (2)
- model (2)
- non-photorealistic rendering (2)
- relevance (2)
- scientific workflows (2)
- secondary computer science education (2)
- systems biology (2)
- theorem (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 lenses (1)
- 3D printing (1)
- 3D semiotics (1)
- 3D visualization (1)
- 3D-Stadtmodelle (1)
- 3d city models (1)
- 6LoWPAN (1)
- ABRACADABRA (1)
- ASIC (1)
- ASIC (Applikationsspezifische Integrierte Schaltkreise) (1)
- ASP (Answer Set Programming) (1)
- Abbrecherquote (1)
- Abstraktion (1)
- Accepting Grammars (1)
- Achievement (1)
- Ackerschmalwand (1)
- Active Evaluation (1)
- Activity Theory (1)
- Activity-orientated Learning (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)
- Applied Game Theory (1)
- Arduino (1)
- Argumentation (1)
- Artificial Intelligence (1)
- Aspect-Oriented Programming (1)
- Aspektorientierte Programmierung (1)
- Assessment (1)
- Asynchrone Schaltung (1)
- Augenbewegungen (1)
- Ausreissererkennung (1)
- Austria (1)
- Authentifizierung (1)
- Automated Theorem Proving (1)
- BCI (1)
- BSS (1)
- Bachelorstudierende der Informatik (1)
- Baumweite (1)
- Behavior (1)
- Berührungseingaben (1)
- Beweis (1)
- Beweisassistent (1)
- Beweistheorie (1)
- Beweisumgebung (1)
- Bilddatenanalyse (1)
- Bildung (1)
- Bildverarbeitung (1)
- Binäres Entscheidungsdiagramm (1)
- Bio-jETI (1)
- Bioelektrisches Signal (1)
- Bioinformatik (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)
- Challenges (1)
- Choreographien (1)
- Classification (1)
- Clause Learning (1)
- Cloud Computing (1)
- Cloud computing (1)
- Clusteranalyse (1)
- Cognitive Skills (1)
- Common Spatial Pattern (1)
- Competences (1)
- Competencies (1)
- Compliance (1)
- Composition (1)
- Computational Complexity (1)
- Computational Thinking (1)
- Computer Science in Context (1)
- Computergrafik (1)
- Computing (1)
- Contest (1)
- Contextualisation (1)
- Contradictions (1)
- Controlled Derivations (1)
- Coq (1)
- Covariate Shift (1)
- Curriculum (1)
- Curriculum Development (1)
- Curry (1)
- DDoS (1)
- Data Analysis (1)
- Data Management (1)
- Databases (1)
- Datenschutz (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)
- Didaktik der Informatik (1)
- Dienstkomposition (1)
- Dienstplattform (1)
- Differenz von Gauss Filtern (1)
- Digital Competence (1)
- Digital Design (1)
- Digital Education (1)
- Digital Revolution (1)
- Distributed Computing (1)
- Dynamic Programming (1)
- Dynamic assessment (1)
- Dynamische Programmierung (1)
- Dynamische Rekonfiguration (1)
- E-Learning (1)
- Early Literacy (1)
- Echtzeitanwendung (1)
- Educational Standards (1)
- Educational software (1)
- Eingabegenauigkeit (1)
- Elektroencephalographie (1)
- Embedded Systems (1)
- Emotionen (1)
- Emotionsforschung (1)
- Entscheidungsbäume (1)
- Entwurfsmuster für SOA-Sicherheit (1)
- Entwurfsprinzipien (1)
- Equilibrium logic (1)
- Erfüllbarkeit einer Formel der Aussagenlogik (1)
- Erfüllbarkeitsproblem (1)
- Error Estimation (1)
- Euclid’s algorithm (1)
- European Bioinformatics Institute (1)
- Evidenztheorie (1)
- Exploration (1)
- Exponential Time Hypothesis (1)
- Exponentialzeit Hypothese (1)
- FMC-QE (1)
- Facebook (1)
- Feature Combination (1)
- Feedback (1)
- Fehlende Daten (1)
- Fehlerschätzung (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)
- Function (1)
- Fundamental Ideas (1)
- GIS-Dienstkomposition (1)
- GPU (1)
- Gebäudemodelle (1)
- Gehirn-Computer-Schnittstelle (1)
- Geländemodelle (1)
- Generalisierung (1)
- Geodaten (1)
- Geometrieerzeugung (1)
- Geovisualisierung (1)
- Geschäftsprozessmodelle (1)
- Gesichtsausdruck (1)
- Gesteuerte Ableitungen (1)
- Gleichheit (1)
- Globus (1)
- Grammar Systems (1)
- Grammatiksysteme (1)
- Graphensuche (1)
- Grid (1)
- Grid Computing (1)
- Hardware Design (1)
- Hauptkomponentenanalyse (1)
- High-Level Synthesis (1)
- Hochschulsystem (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)
- Informatikdidaktik (1)
- Informatikvoraussetzungen (1)
- Information Transfer Rate (1)
- Inkonsistenz (1)
- Inquiry-based Learning (1)
- Integration (1)
- Interactive Rendering (1)
- Interaktionsmodel (1)
- Interaktionsmodellierung (1)
- Interaktives Rendering (1)
- Interface design (1)
- Internet Security (1)
- Internet applications (1)
- Internet-Sicherheit (1)
- Internetanwendungen (1)
- Interoperability (1)
- Interoperabilität (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)
- Komplexität (1)
- Komplexitätsbewältigung (1)
- Komplexitätstheorie (1)
- Komposition (1)
- Konnektionskalkül (1)
- Kryptographie (1)
- Kybernetik (1)
- Landmarken (1)
- Large Margin Classification (1)
- Laser Cutten (1)
- Learners (1)
- Learning Fields (1)
- Learning ecology (1)
- Learning interfaces development (1)
- Learning with ICT (1)
- Leftmost Derivations (1)
- Lehrer (1)
- Leistungsfähigkeit (1)
- Leistungsvorhersage (1)
- Liguistisch (1)
- Linksableitungen (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)
- Mensch-Computer-Interaktion (1)
- Message Passing Interface (1)
- Migration (1)
- Mischmodelle (1)
- Mischung <Signalverarbeitung> (1)
- Mobilgeräte (1)
- Model Management (1)
- Model-Driven Engineering (1)
- Modeling (1)
- Modell Management (1)
- Modell-driven Security (1)
- Modell-getriebene Sicherheit (1)
- Modellgetriebene Entwicklung (1)
- Modellierung (1)
- Molekulare Bioinformatik (1)
- Multi Task Learning (1)
- Multi-Class (1)
- Multi-Task-Lernen (1)
- Multiprocessor (1)
- Multiprozessor (1)
- Music Technology (1)
- NETCONF (1)
- NUI (1)
- Natural Science Education (1)
- Network Management (1)
- Netzwerk (1)
- Netzwerk Management (1)
- Netzwerke (1)
- Neuronales Netz (1)
- Next Generation Network (1)
- Nicht-photorealistisches Rendering (1)
- Nichtfotorealistische Bildsynthese (1)
- NoSQL (1)
- Norway (1)
- Novice programmers (1)
- Nutzungsinteresse (1)
- Objektive Schwierigkeit (1)
- Omega (1)
- Ontologien (1)
- Ontologies (1)
- Ontology (1)
- Optimierungsproblem (1)
- Owner-Retained Access Control (ORAC) (1)
- Parallel Programming (1)
- Paralleles Rechnen (1)
- Parallelrechner (1)
- Parameterized Complexity (1)
- Parametrisierte Komplexität (1)
- Parsing (1)
- Pedagogical content knowledge (1)
- Peer-to-Peer-Netz ; GRID computing ; Zuverlässigkeit ; Web Services ; Betriebsmittelverwaltung ; Migration (1)
- Performance (1)
- Performance Prediction (1)
- Physical Science (1)
- Platzierung (1)
- Policy Enforcement (1)
- Policy Languages (1)
- Policy Sprachen (1)
- Power Monitoring (1)
- Prediction Game (1)
- Predictive Models (1)
- Preprocessing (1)
- Problem Solving (1)
- Probleme in der Studie (1)
- Process (1)
- Process modeling (1)
- Professoren (1)
- Programmierung (1)
- Proof Theory (1)
- Prozess (1)
- Prozesse (1)
- Prozessmodellierung (1)
- Prozesssynchronisierung (1)
- Prädiktionsspiel (1)
- Präferenzen (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)
- Reparatur (1)
- SMT (SAT Modulo Theories) (1)
- SOA Security Pattern (1)
- STG decomposition (1)
- STG-Dekomposition (1)
- Sample Selection Bias (1)
- Satisfiability (1)
- Scalability (1)
- Schlüsselkompetenzen (1)
- Schulmaterial (1)
- Security Modelling (1)
- Segmentierung (1)
- Selektion (1)
- Selektionsbias (1)
- Semantic Search (1)
- Semantik Web (1)
- Semantische Suche (1)
- Sensornetzwerke (1)
- Sensors (1)
- Service Creation (1)
- Service Delivery Platform (1)
- Service convergence (1)
- Service-Orientierte Architekturen (1)
- Service-oriented Architectures (1)
- Shader (1)
- Sicherheitsmodellierung (1)
- Signal Processing (1)
- Signalquellentrennung (1)
- Signaltrennung (1)
- Simultane Diagonalisierung (1)
- Single Event Transient (1)
- Single Trial Analysis (1)
- Skalierbarkeit (1)
- Skelettberechnung (1)
- Small Private Online Courses (1)
- Social (1)
- Software-basierte Cache-Kohärenz (1)
- Sonnenteilchen-Ereignis (1)
- Spam (1)
- Spam Filtering (1)
- Spam-Erkennung (1)
- Spam-Filter (1)
- Spam-Filtering (1)
- Spatio-Spectral Filter (1)
- Spawning (1)
- Sprachdesign (1)
- Statistical Tests (1)
- Statistische Tests (1)
- Stilisierung (1)
- Strahlungshartes Design (1)
- Strahlungshärte Entwurf (1)
- Stromverbrauchüberwachung (1)
- Structuring (1)
- Strukturierung (1)
- Studentenerwartungen (1)
- Studentenhaltungen (1)
- Support Vectors (1)
- Support-Vector Lernen (1)
- Synthese (1)
- System Biologie (1)
- Systembiologie (1)
- TPTP (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)
- Tests (1)
- Texturen (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)
- Unabhängige Komponentenanalyse (1)
- Universität Bagdad (1)
- Universität Potsdam (1)
- Universitätseinstellungen (1)
- Untere Schranken (1)
- Unterrichtswerkzeuge (1)
- Unvollständigkeit (1)
- Usage Interest (1)
- VM (1)
- Verhalten (1)
- Verifikation (1)
- Verletzung Auflösung (1)
- Verletzung Erklärung (1)
- Verteiltes Rechnen (1)
- Verteilungsunterschied (1)
- Violation Explanation (1)
- Violation Resolution (1)
- Virtuelles 3D Stadtmodell (1)
- Visualisierung (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)
- 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)
- 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)
- 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 modifiability (1)
- coherence-enhancing filtering (1)
- communication (1)
- competence (1)
- competencies (1)
- competency (1)
- comprehension (1)
- computational biology (1)
- computational methods (1)
- computer graphics (1)
- computer science teachers (1)
- computer security (1)
- computergestützte Methoden (1)
- concurrent checking (1)
- connection calculus (1)
- constraints (1)
- cryptography (1)
- cs4fn (1)
- curriculum theory (1)
- decision trees (1)
- deep neural networks (1)
- degree of formality (1)
- design principles (1)
- didaktische Rekonstruktion (1)
- difference of Gaussians (1)
- digital circuit (1)
- digital design (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)
- 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)
- entity alignment (1)
- environments (1)
- epistemic logic programs (1)
- epistemic specifications (1)
- equality (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)
- fun (1)
- generalization (1)
- geometry generation (1)
- geospatial data (1)
- geospatial services (1)
- geovisualization (1)
- graph clustering (1)
- graph-search (1)
- hardware design (1)
- high school (1)
- high-throughput analysis (1)
- higher (1)
- human computer interaction (1)
- hybrid (1)
- hybrides Problemlösen (1)
- image (1)
- image data analysis (1)
- image processing (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)
- informatische Bildung im Sekundarbereich (1)
- innovation (1)
- input accuracy (1)
- interaction modeling (1)
- interactive course (1)
- interactive workshop (1)
- kernel PCA (1)
- kernel methods (1)
- key competences in physical computing (1)
- key competencies (1)
- kinaesthetic teaching (1)
- konvergente Dienste (1)
- landmarks (1)
- language design (1)
- leanCoP (1)
- learning (1)
- lesson planning (1)
- lesson preparation (1)
- linguistic (1)
- logic (1)
- logic programming (1)
- logic synthesis (1)
- logical calculus (1)
- logical signaling networks (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)
- middleware (1)
- mixture models (1)
- mobile devices (1)
- mobile learning (1)
- mobile technologies and apps (1)
- molecular networks (1)
- molekulare Netzwerke (1)
- multi-class classification (1)
- multiuser (1)
- network (1)
- networks (1)
- networks-on-chip (1)
- nichtlineare ICA (1)
- nichtlineare PCA (NLPCA) (1)
- non-monotonic reasoning (1)
- nonlinear ICA (1)
- nonlinear PCA (NLPCA) (1)
- objective difficulty (1)
- omega (1)
- one-sided communication (1)
- oneM2M (1)
- online assistance (1)
- ontologies (1)
- operating system (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 synchronization (1)
- professional development (1)
- professors (1)
- programming (1)
- programming in context (1)
- proof (1)
- proof assistant (1)
- proof environment (1)
- propagation probability (1)
- proving (1)
- quantum cryptography (1)
- radiation hardness (1)
- radiation hardness design (1)
- real-time application (1)
- reconfiguration (1)
- rekonfigurierbar (1)
- reliability assessment (1)
- repair (1)
- robust ICA (1)
- robuste ICA (1)
- scheduling (1)
- secondary education (1)
- security (1)
- segmentation (1)
- selbstanpassendes Multiprozessorsystem (1)
- selection (1)
- self-adaptive multiprocessing system (1)
- self-efficacy (1)
- semantic domain modeling (1)
- semantische Domänenmodellierung (1)
- service composition (1)
- shader (1)
- sign language (1)
- single event upset (1)
- skeletonization (1)
- social media (1)
- software-based cache coherence (1)
- solar particle event (1)
- speed independence (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)
- tactic (1)
- teacher competencies (1)
- teacher training (1)
- teachers (1)
- teaching informatics in general education (1)
- temporary binding (1)
- terrain models (1)
- test (1)
- textures (1)
- tools (1)
- tools for teaching (1)
- topics (1)
- touch input (1)
- tptp (1)
- tracing (1)
- transformation (1)
- tutorial section (1)
- unification (1)
- user interfaces (1)
- user-centred (1)
- verification (1)
- virtual 3D city model (1)
- virtual 3D city models (1)
- virtual machine (1)
- virtual mobility (1)
- virtual reality (1)
- virtuelle 3D-Stadtmodelle (1)
- visualization (1)
- weather extremes (1)
- workflow management (1)
- zero-aliasing (1)
- überbestimmte ICA (1)
- ‘unplugged’ computing (1)
Due to anthropogenic greenhouse gas emissions, Earth’s average surface temperature is steadily increasing. As a consequence, many weather extremes are likely to become more frequent and intense. This poses a threat to natural and human systems, with local impacts capable of destroying exposed assets and infrastructure, and disrupting economic and societal activity. Yet, these effects are not locally confined to the directly affected regions, as they can trigger indirect economic repercussions through loss propagation along supply chains. As a result, local extremes yield a potentially global economic response. To build economic resilience and design effective adaptation measures that mitigate adverse socio-economic impacts of ongoing climate change, it is crucial to gain a comprehensive understanding of indirect impacts and the underlying economic mechanisms.
Presenting six articles in this thesis, I contribute towards this understanding. To this end, I expand on local impacts under current and future climate, the resulting global economic response, as well as the methods and tools to analyze this response.
Starting with a traditional assessment of weather extremes under climate change, the first article investigates extreme snowfall in the Northern Hemisphere until the end of the century. Analyzing an ensemble of global climate model projections reveals an increase of the most extreme snowfall, while mean snowfall decreases.
Assessing repercussions beyond local impacts, I employ numerical simulations to compute indirect economic effects from weather extremes with the numerical agent-based shock propagation model Acclimate. This model is used in conjunction with the recently emerged storyline framework, which involves analyzing the impacts of a particular reference extreme event and comparing them to impacts in plausible counterfactual scenarios under various climate or socio-economic conditions. Using this approach, I introduce three primary storylines that shed light on the complex mechanisms underlying economic loss propagation.
In the second and third articles of this thesis, I analyze storylines for the historical Hurricanes Sandy (2012) and Harvey (2017) in the USA. For this, I first estimate local economic output losses and then simulate the resulting global economic response with Acclimate. The storyline for Hurricane Sandy thereby focuses on global consumption price anomalies and the resulting changes in consumption. I find that the local economic disruption leads to a global wave-like economic price ripple, with upstream effects propagating in the supplier direction and downstream effects in the buyer direction. Initially, an upstream demand reduction causes consumption price decreases, followed by a downstream supply shortage and increasing prices, before the anomalies decay in a normalization phase. A dominant upstream or downstream effect leads to net consumption gains or losses of a region, respectively. Moreover, I demonstrate that a longer direct economic shock intensifies the downstream effect for many regions, leading to an overall consumption loss.
The third article of my thesis builds upon the developed loss estimation method by incorporating projections to future global warming levels. I use these projections to explore how the global production response to Hurricane Harvey would change under further increased global warming. The results show that, while the USA is able to nationally offset direct losses in the reference configuration, other countries have to compensate for increasing shares of counterfactual future losses. This compensation is mainly achieved by large exporting countries, but gradually shifts towards smaller regions. These findings not only highlight the economy’s ability to flexibly mitigate disaster losses to a certain extent, but also reveal the vulnerability and economic disadvantage of regions that are exposed to extreme weather events.
The storyline in the fourth article of my thesis investigates the interaction between global economic stress and the propagation of losses from weather extremes. I examine indirect impacts of weather extremes — tropical cyclones, heat stress, and river floods — worldwide under two different economic conditions: an unstressed economy and a globally stressed economy, as seen during the Covid-19 pandemic. I demonstrate that the adverse effects of weather extremes on global consumption are strongly amplified when the economy is under stress. Specifically, consumption losses in the USA and China double and triple, respectively, due to the global economy’s decreased capacity for disaster loss compensation. An aggravated scarcity intensifies the price response, causing consumption losses to increase.
Advancing on the methods and tools used here, the final two articles in my thesis extend the agent-based model Acclimate and formalize the storyline approach. With the model extension described in the fifth article, regional consumers make rational choices on the goods bought such that their utility is maximized under a constrained budget. In an out-of-equilibrium economy, these rational consumers are shown to temporarily increase consumption of certain goods in spite of rising prices.
The sixth article of my thesis proposes a formalization of the storyline framework, drawing on multiple studies including storylines presented in this thesis. The proposed guideline defines eight central elements that can be used to construct a storyline.
Overall, this thesis contributes towards a better understanding of economic repercussions of weather extremes. It achieves this by providing assessments of local direct impacts, highlighting mechanisms and impacts of loss propagation, and advancing on methods and tools used.
In this bachelor’s thesis I implement the automatic theorem prover nanoCoP-Ω. This system is the result of porting arithmetic and equality handling procedures first introduced in the automatic theorem prover with arithmetic leanCoP-Ω into the similar system nanoCoP 2.0. To understand these procedures, I first introduce the mathematical background to both automatic theorem proving and arithmetic expressions. I present the predecessor projects leanCoP, nanoCoP and leanCoP-Ω, out of which nanCoP-Ω was developed. This is followed by an extensive description of the concepts the non-clausal connection calculus needed to be extended by, to allow for proving arithmetic expressions and equalities, as well as of their implementation into nanoCoP-Ω. An extensive comparison between both the runtimes and the number of solved problems of the systems nanoCoP-Ω and leanCoP-Ω was made. I come to the conclusion, that nanoCoP-Ω is considerably faster than leanCoP-Ω for small problems, though less well suited for larger problems. Additionally, I was able to construct a non-theorem that nanoCoP-Ω generates a false proof for. I discuss how this pressing issue could be resolved, as well as some possible optimizations and expansions of the system.
Reliable and robust data processing is one of the hardest requirements for systems in fields such as medicine, security, automotive, aviation, and space, to prevent critical system failures caused by changes in operating or environmental conditions. In particular, Signal Integrity (SI) effects such as crosstalk may distort the signal information in sensitive mixed-signal designs. A challenge for hardware systems used in the space are radiation effects. Namely, Single Event Effects (SEEs) induced by high-energy particle hits may lead to faulty computation, corrupted configuration settings, undesired system behavior, or even total malfunction.
Since these applications require an extra effort in design and implementation, it is beneficial to master the standard cell design process and corresponding design flow methodologies optimized for such challenges. Especially for reliable, low-noise differential signaling logic such as Current Mode Logic (CML), a digital design flow is an orthogonal approach compared to traditional manual design. As a consequence, mandatory preliminary considerations need to be addressed in more detail. First of all, standard cell library concepts with suitable cell extensions for reliable systems and robust space applications have to be elaborated. Resulting design concepts at the cell level should enable the logical synthesis for differential logic design or improve the radiation-hardness. In parallel, the main objectives of the proposed cell architectures are to reduce the occupied area, power, and delay overhead. Second, a special setup for standard cell characterization is additionally required for a proper and accurate logic gate modeling. Last but not least, design methodologies for mandatory design flow stages such as logic synthesis and place and route need to be developed for the respective hardware systems to keep the reliability or the radiation-hardness at an acceptable level.
This Thesis proposes and investigates standard cell-based design methodologies and techniques for reliable and robust hardware systems implemented in a conventional semi-conductor technology. The focus of this work is on reliable differential logic design and robust radiation-hardening-by-design circuits. The synergistic connections of the digital design flow stages are systematically addressed for these two types of hardware systems. In more detail, a library for differential logic is extended with single-ended pseudo-gates for intermediate design steps to support the logic synthesis and layout generation with commercial Computer-Aided Design (CAD) tools. Special cell layouts are proposed to relax signal routing. A library set for space applications is similarly extended by novel Radiation-Hardening-by-Design (RHBD) Triple Modular Redundancy (TMR) cells, enabling a one fault correction. Therein, additional optimized architectures for glitch filter cells, robust scannable and self-correcting flip-flops, and clock-gates are proposed. The circuit concepts and the physical layout representation views of the differential logic gates and the RHBD cells are discussed. However, the quality of results of designs depends implicitly on the accuracy of the standard cell characterization which is examined for both types therefore. The entire design flow is elaborated from the hardware design description to the layout representations. A 2-Phase routing approach together with an intermediate design conversion step is proposed after the initial place and route stage for reliable, pure differential designs, whereas a special constraining for RHBD applications in a standard technology is presented.
The digital design flow for differential logic design is successfully demonstrated on a reliable differential bipolar CML application. A balanced routing result of its differential signal pairs is obtained by the proposed 2-Phase-routing approach. Moreover, the elaborated standard cell concepts and design methodology for RHBD circuits are applied to the digital part of a 7.5-15.5 MSPS 14-bit Analog-to-Digital Converter (ADC) and a complex microcontroller architecture. The ADC is implemented in an unhardened standard semiconductor technology and successfully verified by electrical measurements. The overhead of the proposed hardening approach is additionally evaluated by design exploration of the microcontroller application. Furthermore, the first obtained related measurement results of novel RHBD-∆TMR flip-flops show a radiation-tolerance up to a threshold Linear Energy Transfer (LET) of 46.1, 52.0, and 62.5 MeV cm2 mg-1 and savings in silicon area of 25-50 % for selected TMR standard cell candidates.
As a conclusion, the presented design concepts at the cell and library levels, as well as the design flow modifications are adaptable and transferable to other technology nodes. In particular, the design of hybrid solutions with integrated reliable differential logic modules together with robust radiation-tolerant circuit parts is enabled by the standard cell concepts and design methods proposed in this work.
Accurately solving classification problems nowadays is likely to be the most relevant machine learning task. Binary classification separating two classes only is algorithmically simpler but has fewer potential applications as many real-world problems are multi-class. On the reverse, separating only a subset of classes simplifies the classification task. Even though existing multi-class machine learning algorithms are very flexible regarding the number of classes, they assume that the target set Y is fixed and cannot be restricted once the training is finished. On the other hand, existing state-of-the-art production environments are becoming increasingly interconnected with the advance of Industry 4.0 and related technologies such that additional information can simplify the respective classification problems. In light of this, the main aim of this thesis is to introduce dynamic classification that generalizes multi-class classification such that the target class set can be restricted arbitrarily to a non-empty class subset M of Y at any time between two consecutive predictions.
This task is solved by a combination of two algorithmic approaches. First, classifier calibration, which transforms predictions into posterior probability estimates that are intended to be well calibrated. The analysis provided focuses on monotonic calibration and in particular corrects wrong statements that appeared in the literature. It also reveals that bin-based evaluation metrics, which became popular in recent years, are unjustified and should not be used at all. Next, the validity of Platt scaling, which is the most relevant parametric calibration approach, is analyzed in depth. In particular, its optimality for classifier predictions distributed according to four different families of probability distributions as well its equivalence with Beta calibration up to a sigmoidal preprocessing are proven. For non-monotonic calibration, extended variants on kernel density estimation and the ensemble method EKDE are introduced. Finally, the calibration techniques are evaluated using a simulation study with complete information as well as on a selection of 46 real-world data sets.
Building on this, classifier calibration is applied as part of decomposition-based classification that aims to reduce multi-class problems to simpler (usually binary) prediction tasks. For the involved fusing step performed at prediction time, a new approach based on evidence theory is presented that uses classifier calibration to model mass functions. This allows the analysis of decomposition-based classification against a strictly formal background and to prove closed-form equations for the overall combinations. Furthermore, the same formalism leads to a consistent integration of dynamic class information, yielding a theoretically justified and computationally tractable dynamic classification model. The insights gained from this modeling are combined with pairwise coupling, which is one of the most relevant reduction-based classification approaches, such that all individual predictions are combined with a weight. This not only generalizes existing works on pairwise coupling but also enables the integration of dynamic class information.
Lastly, a thorough empirical study is performed that compares all newly introduced approaches to existing state-of-the-art techniques. For this, evaluation metrics for dynamic classification are introduced that depend on corresponding sampling strategies. Thereafter, these are applied during a three-part evaluation. First, support vector machines and random forests are applied on 26 data sets from the UCI Machine Learning Repository. Second, two state-of-the-art deep neural networks are evaluated on five benchmark data sets from a relatively recent reference work. Here, computationally feasible strategies to apply the presented algorithms in combination with large-scale models are particularly relevant because a naive application is computationally intractable. Finally, reference data from a real-world process allowing the inclusion of dynamic class information are collected and evaluated. The results show that in combination with support vector machines and random forests, pairwise coupling approaches yield the best results, while in combination with deep neural networks, differences between the different approaches are mostly small to negligible. Most importantly, all results empirically confirm that dynamic classification succeeds in improving the respective prediction accuracies. Therefore, it is crucial to pass dynamic class information in respective applications, which requires an appropriate digital infrastructure.
As a result of CMOS scaling, radiation-induced Single-Event Effects (SEEs) in electronic circuits became a critical reliability issue for modern Integrated Circuits (ICs) operating under harsh radiation conditions. SEEs can be triggered in combinational or sequential logic by the impact of high-energy particles, leading to destructive or non-destructive faults, resulting in data corruption or even system failure. Typically, the SEE mitigation methods are deployed statically in processing architectures based on the worst-case radiation conditions, which is most of the time unnecessary and results in a resource overhead. Moreover, the space radiation conditions are dynamically changing, especially during Solar Particle Events (SPEs). The intensity of space radiation can differ over five orders of magnitude within a few hours or days, resulting in several orders of magnitude fault probability variation in ICs during SPEs. This thesis introduces a comprehensive approach for designing a self-adaptive fault resilient multiprocessing system to overcome the static mitigation overhead issue. This work mainly addresses the following topics: (1) Design of on-chip radiation particle monitor for real-time radiation environment detection, (2) Investigation of space environment predictor, as support for solar particle events forecast, (3) Dynamic mode configuration in the resilient multiprocessing system. Therefore, according to detected and predicted in-flight space radiation conditions, the target system can be configured to use no mitigation or low-overhead mitigation during non-critical periods of time. The redundant resources can be used to improve system performance or save power. On the other hand, during increased radiation activity periods, such as SPEs, the mitigation methods can be dynamically configured appropriately depending on the real-time space radiation environment, resulting in higher system reliability. Thus, a dynamic trade-off in the target system between reliability, performance and power consumption in real-time can be achieved. All results of this work are evaluated in a highly reliable quad-core multiprocessing system that allows the self-adaptive setting of optimal radiation mitigation mechanisms during run-time. Proposed methods can serve as a basis for establishing a comprehensive self-adaptive resilient system design process. Successful implementation of the proposed design in the quad-core multiprocessor shows its application perspective also in the other designs.
The highly structured nature of the educational sector demands effective policy mechanisms close to the needs of the field. That is why evidence-based policy making, endorsed by the European Commission under Erasmus+ Key Action 3, aims to make an alignment between the domains of policy and practice. Against this background, this article addresses two issues: First, that there is a vertical gap in the translation of higher-level policies to local strategies and regulations. Second, that there is a horizontal gap between educational domains regarding the policy awareness of individual players. This was analyzed in quantitative and qualitative studies with domain experts from the fields of virtual mobility and teacher training. From our findings, we argue that the combination of both gaps puts the academic bridge from secondary to tertiary education at risk, including the associated knowledge proficiency levels. We discuss the role of digitalization in the academic bridge by asking the question: which value does the involved stakeholders expect from educational policies? As a theoretical basis, we rely on the model of value co-creation for and by stakeholders. We describe the used instruments along with the obtained results and proposed benefits. Moreover, we reflect on the methodology applied, and we finally derive recommendations for future academic bridge policies.
Large-scale databases that report the inhibitory capacities of many combinations of candidate drug compounds and cultivated cancer cell lines have driven the development of preclinical drug-sensitivity models based on machine learning. However, cultivated cell lines have devolved from human cancer cells over years or even decades under selective pressure in culture conditions. Moreover, models that have been trained on in vitro data cannot account for interactions with other types of cells. Drug-response data that are based on patient-derived cell cultures, xenografts, and organoids, on the other hand, are not available in the quantities that are needed to train high-capacity machine-learning models. We found that pre-training deep neural network models of drug sensitivity on in vitro drug-sensitivity databases before fine-tuning the model parameters on patient-derived data improves the models’ accuracy and improves the biological plausibility of the features, compared to training only on patient-derived data. From our experiments, we can conclude that pre-trained models outperform models that have been trained on the target domains in the vast majority of cases.
With the downscaling of CMOS technologies, the radiation-induced Single Event Transient (SET) effects in combinational logic have become a critical reliability issue for modern integrated circuits (ICs) intended for operation under harsh radiation conditions. The SET pulses generated in combinational logic may propagate through the circuit and eventually result in soft errors. It has thus become an imperative to address the SET effects in the early phases of the radiation-hard IC design. In general, the soft error mitigation solutions should accommodate both static and dynamic measures to ensure the optimal utilization of available resources. An efficient soft-error-aware design should address synergistically three main aspects: (i) characterization and modeling of soft errors, (ii) multi-level soft error mitigation, and (iii) online soft error monitoring. Although significant results have been achieved, the effectiveness of SET characterization methods, accuracy of predictive SET models, and efficiency of SET mitigation measures are still critical issues. Therefore, this work addresses the following topics: (i) Characterization and modeling of SET effects in standard combinational cells, (ii) Static mitigation of SET effects in standard combinational cells, and (iii) Online particle detection, as a support for dynamic soft error mitigation.
Since the standard digital libraries are widely used in the design of radiation-hard ICs, the characterization of SET effects in standard cells and the availability of accurate SET models for the Soft Error Rate (SER) evaluation are the main prerequisites for efficient radiation-hard design. This work introduces an approach for the SPICE-based standard cell characterization with the reduced number of simulations, improved SET models and optimized SET sensitivity database. It has been shown that the inherent similarities in the SET response of logic cells for different input levels can be utilized to reduce the number of required simulations. Based on characterization results, the fitting models for the SET sensitivity metrics (critical charge, generated SET pulse width and propagated SET pulse width) have been developed. The proposed models are based on the principle of superposition, and they express explicitly the dependence of the SET sensitivity of individual combinational cells on design, operating and irradiation parameters. In contrast to the state-of-the-art characterization methodologies which employ extensive look-up tables (LUTs) for storing the simulation results, this work proposes the use of LUTs for storing the fitting coefficients of the SET sensitivity models derived from the characterization results. In that way the amount of characterization data in the SET sensitivity database is reduced significantly.
The initial step in enhancing the robustness of combinational logic is the application of gate-level mitigation techniques. As a result, significant improvement of the overall SER can be achieved with minimum area, delay and power overheads. For the SET mitigation in standard cells, it is essential to employ the techniques that do not require modifying the cell structure. This work introduces the use of decoupling cells for improving the robustness of standard combinational cells. By insertion of two decoupling cells at the output of a target cell, the critical charge of the cell’s output node is increased and the attenuation of short SETs is enhanced. In comparison to the most common gate-level techniques (gate upsizing and gate duplication), the proposed approach provides better SET filtering. However, as there is no single gate-level mitigation technique with optimal performance, a combination of multiple techniques is required. This work introduces a comprehensive characterization of gate-level mitigation techniques aimed to quantify their impact on the SET robustness improvement, as well as introduced area, delay and power overhead per gate. By characterizing the gate-level mitigation techniques together with the standard cells, the required effort in subsequent SER analysis of a target design can be reduced. The characterization database of the hardened standard cells can be utilized as a guideline for selection of the most appropriate mitigation solution for a given design.
As a support for dynamic soft error mitigation techniques, it is important to enable the online detection of energetic particles causing the soft errors. This allows activating the power-greedy fault-tolerant configurations based on N-modular redundancy only at the high radiation levels. To enable such a functionality, it is necessary to monitor both the particle flux and the variation of particle LET, as these two parameters contribute significantly to the system SER. In this work, a particle detection approach based on custom-sized pulse stretching inverters is proposed. Employing the pulse stretching inverters connected in parallel enables to measure the particle flux in terms of the number of detected SETs, while the particle LET variations can be estimated from the distribution of SET pulse widths. This approach requires a purely digital processing logic, in contrast to the standard detectors which require complex mixed-signal processing. Besides the possibility of LET monitoring, additional advantages of the proposed particle detector are low detection latency and power consumption, and immunity to error accumulation.
The results achieved in this thesis can serve as a basis for establishment of an overall soft-error-aware database for a given digital library, and a comprehensive multi-level radiation-hard design flow that can be implemented with the standard IC design tools. The following step will be to evaluate the achieved results with the irradiation experiments.
The Internet of Things (IoT) is a system of physical objects that can be discovered, monitored, controlled, or interacted with by electronic devices that communicate over various networking interfaces and eventually can be connected to the wider Internet. [Guinard and Trifa, 2016]. IoT devices are equipped with sensors and/or actuators and may be constrained in terms of memory, computational power, network bandwidth, and energy. Interoperability can help to manage such heterogeneous devices. Interoperability is the ability of different types of systems to work together smoothly. There are four levels of interoperability: physical, network and transport, integration, and data. The data interoperability is subdivided into syntactic and semantic data. Semantic data describes the meaning of data and the common understanding of vocabulary e.g. with the help of dictionaries, taxonomies, ontologies. To achieve interoperability, semantic interoperability is necessary.
Many organizations and companies are working on standards and solutions for interoperability in the IoT. However, the commercial solutions produce a vendor lock-in. They focus on centralized approaches such as cloud-based solutions. This thesis proposes a decentralized approach namely Edge Computing. Edge Computing is based on the concepts of mesh networking and distributed processing. This approach has an advantage that information collection and processing are placed closer to the sources of this information. The goals are to reduce traffic, latency, and to be robust against a lossy or failed Internet connection.
We see management of IoT devices from the network configuration management perspective. This thesis proposes a framework for network configuration management of heterogeneous, constrained IoT devices by using semantic descriptions for interoperability. The MYNO framework is an acronym for MQTT, YANG, NETCONF and Ontology. The NETCONF protocol is the IETF standard for network configuration management. The MQTT protocol is the de-facto standard in the IoT. We picked up the idea of the NETCONF-MQTT bridge, originally proposed by Scheffler and Bonneß[2017], and extended it with semantic device descriptions. These device descriptions provide a description of the device capabilities. They are based on the oneM2M Base ontology and formalized by the Semantic Web Standards.
The novel approach is using a ontology-based device description directly on a constrained device in combination with the MQTT protocol. The bridge was extended in order to query such descriptions. Using a semantic annotation, we achieved that the device capabilities are self-descriptive, machine readable and re-usable.
The concept of a Virtual Device was introduced and implemented, based on semantic device descriptions. A Virtual Device aggregates the capabilities of all devices at the edge network and contributes therefore to the scalability. Thus, it is possible to control all devices via a single RPC call.
The model-driven NETCONF Web-Client is generated automatically from this YANG model which is generated by the bridge based on the semantic device description. The Web-Client provides a user-friendly interface, offers RPC calls and displays sensor values. We demonstrate the feasibility of this approach in different use cases: sensor and actuator scenarios, as well as event configuration and triggering.
The semantic approach results in increased memory overhead. Therefore, we evaluated CBOR and RDF HDT for optimization of ontology-based device descriptions for use on constrained devices. The evaluation shows that CBOR is not suitable for long strings and RDF HDT is a promising candidate but is still a W3C Member Submission. Finally, we used an optimized JSON-LD format for the syntax of the device descriptions.
One of the security tasks of network management is the distribution of firmware updates. The MYNO Update Protocol (MUP) was developed and evaluated on constrained devices CC2538dk and 6LoWPAN. The MYNO update process is focused on freshness and authenticity of the firmware. The evaluation shows that it is challenging but feasible to bring the firmware updates to constrained devices using MQTT. As a new requirement for the next MQTT version, we propose to add a slicing feature for the better support of constrained devices. The MQTT broker should slice data to the maximum packet size specified by the device and transfer it slice-by-slice.
For the performance and scalability evaluation of MYNO framework, we setup the High Precision Agriculture demonstrator with 10 ESP-32 NodeMCU boards at the edge of the network. The ESP-32 NodeMCU boards, connected by WLAN, were equipped with six sensors and two actuators. The performance evaluation shows that the processing of ontology-based descriptions on a Raspberry Pi 3B with the RDFLib is a challenging task regarding computational power. Nevertheless, it is feasible because it must be done only once per device during the discovery process.
The MYNO framework was tested with heterogeneous devices such as CC2538dk from Texas Instruments, Arduino Yún Rev 3, and ESP-32 NodeMCU, and IP-based networks such as 6LoWPAN and WLAN.
Summarizing, with the MYNO framework we could show that the semantic approach on constrained devices is feasible in the IoT.
Research publications and data nowadays should be publicly available on the internet and, theoretically, usable for everyone to develop further research, products, or services. The long-term accessibility of research data is, therefore, fundamental in the economy of the research production process. However, the availability of data is not sufficient by itself, but also their quality must be verifiable. Measures to ensure reuse and reproducibility need to include the entire research life cycle, from the experimental design to the generation of data, quality control, statistical analysis, interpretation, and validation of the results. Hence, high-quality records, particularly for providing a string of documents for the verifiable origin of data, are essential elements that can act as a certificate for potential users (customers). These records also improve the traceability and transparency of data and processes, therefore, improving the reliability of results. Standards for data acquisition, analysis, and documentation have been fostered in the last decade driven by grassroot initiatives of researchers and organizations such as the Research Data Alliance (RDA). Nevertheless, what is still largely missing in the life science academic research are agreed procedures for complex routine research workflows. Here, well-crafted documentation like standard operating procedures (SOPs) offer clear direction and instructions specifically designed to avoid deviations as an absolute necessity for reproducibility. Therefore, this paper provides a standardized workflow that explains step by step how to write an SOP to be used as a starting point for appropriate research documentation.
In the last decades, there was a notable progress in solving the well-known Boolean satisfiability (Sat) problem, which can be witnessed by powerful Sat solvers. One of the reasons why these solvers are so fast are structural properties of instances that are utilized by the solver’s interna. This thesis deals with the well-studied structural property treewidth, which measures the closeness of an instance to being a tree. In fact, there are many problems parameterized by treewidth that are solvable in polynomial time in the instance size when parameterized by treewidth.
In this work, we study advanced treewidth-based methods and tools for problems in knowledge representation and reasoning (KR). Thereby, we provide means to establish precise runtime results (upper bounds) for canonical problems relevant to KR. Then, we present a new type of problem reduction, which we call decomposition-guided (DG) that
allows us to precisely monitor the treewidth when reducing from one problem to another problem. This new reduction type will be the basis for a long-open lower bound result for quantified Boolean formulas and allows us to design a new methodology for establishing runtime lower bounds for problems parameterized by treewidth.
Finally, despite these lower bounds, we provide an efficient implementation of algorithms that adhere to treewidth. Our approach finds suitable abstractions of instances, which are subsequently refined in a recursive fashion, and it uses Sat solvers for solving subproblems. It turns out that our resulting solver is quite competitive for two canonical counting problems related to Sat.
A common feature in Answer Set Programming is the use of a second negation, stronger than default negation and sometimes called explicit, strong or classical negation. This explicit negation is normally used in front of atoms, rather than allowing its use as a regular operator. In this paper we consider the arbitrary combination of explicit negation with nested expressions, as those defined by Lifschitz, Tang and Turner. We extend the concept of reduct for this new syntax and then prove that it can be captured by an extension of Equilibrium Logic with this second negation. We study some properties of this variant and compare to the already known combination of Equilibrium Logic with Nelson's strong negation.
MUP
(2020)
Message Queuing Telemetry Transport (MQTT) is one of the dominating protocols for edge- and cloud-based Internet of Things (IoT) solutions. When a security vulnerability of an IoT device is known, it has to be fixed as soon as possible. This requires a firmware update procedure. In this paper, we propose a secure update protocol for MQTT-connected devices which ensures the freshness of the firmware, authenticates the new firmware and considers constrained devices. We show that the update protocol is easy to integrate in an MQTT-based IoT network using a semantic approach. The feasibility of our approach is demonstrated by a detailed performance analysis of our prototype implementation on a IoT device with 32 kB RAM. Thereby, we identify design issues in MQTT 5 which can help to improve the support of constrained devices.
In a recent line of research, two familiar concepts from logic programming semantics (unfounded sets and splitting) were extrapolated to the case of epistemic logic programs. The property of epistemic splitting provides a natural and modular way to understand programs without epistemic cycles but, surprisingly, was only fulfilled by Gelfond's original semantics (G91), among the many proposals in the literature. On the other hand, G91 may suffer from a kind of self-supported, unfounded derivations when epistemic cycles come into play. Recently, the absence of these derivations was also formalised as a property of epistemic semantics called foundedness. Moreover, a first semantics proved to satisfy foundedness was also proposed, the so-called Founded Autoepistemic Equilibrium Logic (FAEEL). In this paper, we prove that FAEEL also satisfies the epistemic splitting property something that, together with foundedness, was not fulfilled by any other approach up to date. To prove this result, we provide an alternative characterisation of FAEEL as a combination of G91 with a simpler logic we called Founded Epistemic Equilibrium Logic (FEEL), which is somehow an extrapolation of the stable model semantics to the modal logic S5.
Parsing of argumentative structures has become a very active line of research in recent years. Like discourse parsing or any other natural language task that requires prediction of linguistic structures, most approaches choose to learn a local model and then perform global decoding over the local probability distributions, often imposing constraints that are specific to the task at hand. Specifically for argumentation parsing, two decoding approaches have been recently proposed: Minimum Spanning Trees (MST) and Integer Linear Programming (ILP), following similar trends in discourse parsing. In contrast to discourse parsing though, where trees are not always used as underlying annotation schemes, argumentation structures so far have always been represented with trees. Using the 'argumentative microtext corpus' [in: Argumentation and Reasoned Action: Proceedings of the 1st European Conference on Argumentation, Lisbon 2015 / Vol. 2, College Publications, London, 2016, pp. 801-815] as underlying data and replicating three different decoding mechanisms, in this paper we propose a novel ILP decoder and an extension to our earlier MST work, and then thoroughly compare the approaches. The result is that our new decoder outperforms related work in important respects, and that in general, ILP and MST yield very similar performance.
Flux-P
(2012)
Quantitative knowledge of intracellular fluxes in metabolic networks is invaluable for inferring metabolic system behavior and the design principles of biological systems. However, intracellular reaction rates can not often be calculated directly but have to be estimated; for instance, via 13C-based metabolic flux analysis, a model-based interpretation of stable carbon isotope patterns in intermediates of metabolism. Existing software such as FiatFlux, OpenFLUX or 13CFLUX supports experts in this complex analysis, but requires several steps that have to be carried out manually, hence restricting the use of this software for data interpretation to a rather small number of experiments. In this paper, we present Flux-P as an approach to automate and standardize 13C-based metabolic flux analysis, using the Bio-jETI workflow framework. Exemplarily based on the FiatFlux software, it demonstrates how services can be created that carry out the different analysis steps autonomously and how these can subsequently be assembled into software workflows that perform automated, high-throughput intracellular flux analysis of high quality and reproducibility. Besides significant acceleration and standardization of the data analysis, the agile workflow-based realization supports flexible changes of the analysis workflows on the user level, making it easy to perform custom analyses.
A central insight from psychological studies on human eye movements is that eye movement patterns are highly individually characteristic. They can, therefore, be used as a biometric feature, that is, subjects can be identified based on their eye movements. This thesis introduces new machine learning methods to identify subjects based on their eye movements while viewing arbitrary content. The thesis focuses on probabilistic modeling of the problem, which has yielded the best results in the most recent literature. The thesis studies the problem in three phases by proposing a purely probabilistic, probabilistic deep learning, and probabilistic deep metric learning approach. In the first phase, the thesis studies models that rely on psychological concepts about eye movements. Recent literature illustrates that individual-specific distributions of gaze patterns can be used to accurately identify individuals. In these studies, models were based on a simple parametric family of distributions. Such simple parametric models can be robustly estimated from sparse data, but have limited flexibility to capture the differences between individuals. Therefore, this thesis proposes a semiparametric model of gaze patterns that is flexible yet robust for individual identification. These patterns can be understood as domain knowledge derived from psychological literature. Fixations and saccades are examples of simple gaze patterns. The proposed semiparametric densities are drawn under a Gaussian process prior centered at a simple parametric distribution. Thus, the model will stay close to the parametric class of densities if little data is available, but it can also deviate from this class if enough data is available, increasing the flexibility of the model. The proposed method is evaluated on a large-scale dataset, showing significant improvements over the state-of-the-art. Later, the thesis replaces the model based on gaze patterns derived from psychological concepts with a deep neural network that can learn more informative and complex patterns from raw eye movement data. As previous work has shown that the distribution of these patterns across a sequence is informative, a novel statistical aggregation layer called the quantile layer is introduced. It explicitly fits the distribution of deep patterns learned directly from the raw eye movement data. The proposed deep learning approach is end-to-end learnable, such that the deep model learns to extract informative, short local patterns while the quantile layer learns to approximate the distributions of these patterns. Quantile layers are a generic approach that can converge to standard pooling layers or have a more detailed description of the features being pooled, depending on the problem. The proposed model is evaluated in a large-scale study using the eye movements of subjects viewing arbitrary visual input. The model improves upon the standard pooling layers and other statistical aggregation layers proposed in the literature. It also improves upon the state-of-the-art eye movement biometrics by a wide margin. Finally, for the model to identify any subject — not just the set of subjects it is trained on — a metric learning approach is developed. Metric learning learns a distance function over instances. The metric learning model maps the instances into a metric space, where sequences of the same individual are close, and sequences of different individuals are further apart. This thesis introduces a deep metric learning approach with distributional embeddings. The approach represents sequences as a set of continuous distributions in a metric space; to achieve this, a new loss function based on Wasserstein distances is introduced. The proposed method is evaluated on multiple domains besides eye movement biometrics. This approach outperforms the state of the art in deep metric learning in several domains while also outperforming the state of the art in eye movement biometrics.
Emotions are a central element of human experience. They occur with high frequency in everyday life and play an important role in decision making. However, currently there is no consensus among researchers on what constitutes an emotion and on how emotions should be investigated. This dissertation identifies three problems of current emotion research: the problem of ground truth, the problem of incomplete constructs and the problem of optimal representation. I argue for a focus on the detailed measurement of emotion manifestations with computer-aided methods to solve these problems. This approach is demonstrated in three research projects, which describe the development of methods specific to these problems as well as their application to concrete research questions.
The problem of ground truth describes the practice to presuppose a certain structure of emotions as the a priori ground truth. This determines the range of emotion descriptions and sets a standard for the correct assignment of these descriptions. The first project illustrates how this problem can be circumvented with a multidimensional emotion perception paradigm which stands in contrast to the emotion recognition paradigm typically employed in emotion research. This paradigm allows to calculate an objective difficulty measure and to collect subjective difficulty ratings for the perception of emotional stimuli. Moreover, it enables the use of an arbitrary number of emotion stimuli categories as compared to the commonly used six basic emotion categories. Accordingly, we collected data from 441 participants using dynamic facial expression stimuli from 40 emotion categories. Our findings suggest an increase in emotion perception difficulty with increasing actor age and provide evidence to suggest that young adults, the elderly and men underestimate their emotion perception difficulty. While these effects were predicted from the literature, we also found unexpected and novel results. In particular, the increased difficulty on the objective difficulty measure for female actors and observers stood in contrast to reported findings. Exploratory analyses revealed low relevance of person-specific variables for the prediction of emotion perception difficulty, but highlighted the importance of a general pleasure dimension for the ease of emotion perception.
The second project targets the problem of incomplete constructs which relates to vaguely defined psychological constructs on emotion with insufficient ties to tangible manifestations. The project exemplifies how a modern data collection method such as face tracking data can be used to sharpen these constructs on the example of arousal, a long-standing but fuzzy construct in emotion research. It describes how measures of distance, speed and magnitude of acceleration can be computed from face tracking data and investigates their intercorrelations. We find moderate to strong correlations among all measures of static information on one hand and all measures of dynamic information on the other. The project then investigates how self-rated arousal is tied to these measures in 401 neurotypical individuals and 19 individuals with autism. Distance to the neutral face was predictive of arousal ratings in both groups. Lower mean arousal ratings were found for the autistic group, but no difference in correlation of the measures and arousal ratings could be found between groups. Results were replicated in a high autistic traits group consisting of 41 participants. The findings suggest a qualitatively similar perception of arousal for individuals with and without autism. No correlations between valence ratings and any of the measures could be found which emphasizes the specificity of our tested measures for the construct of arousal.
The problem of optimal representation refers to the search for the best representation of emotions and the assumption that there is a one-fits-all solution. In the third project we introduce partial least squares analysis as a general method to find an optimal representation to relate two high-dimensional data sets to each other. The project demonstrates its applicability to emotion research on the question of emotion perception differences between men and women. The method was used with emotion rating data from 441 participants and face tracking data computed on 306 videos. We found quantitative as well as qualitative differences in the perception of emotional facial expressions between these groups. We showed that women’s emotional perception systematically captured more of the variance in facial expressions. Additionally, we could show that significant differences exist in the way that women and men perceive some facial expressions which could be visualized as concrete facial expression sequences. These expressions suggest differing perceptions of masked and ambiguous facial expressions between the sexes. In order to facilitate use of the developed method by the research community, a package for the statistical environment R was written. Furthermore, to call attention to the method and its usefulness for emotion research, a website was designed that allows users to explore a model of emotion ratings and facial expression data in an interactive fashion.
PLATON
(2019)
Lesson planning is both an important and demanding task—especially as part of teacher training. This paper presents the requirements for a lesson planning system and evaluates existing systems regarding these requirements. One major drawback of existing software tools is that most are limited to a text- or form-based representation of the lesson designs. In this article, a new approach with a graphical, time-based representation with (automatic) analyses methods is proposed and the system architecture and domain model are described in detail. The approach is implemented in an interactive, web-based prototype called PLATON, which additionally supports the management of lessons in units as well as the modelling of teacher and student-generated resources. The prototype was evaluated in a study with 61 prospective teachers (bachelor’s and master’s preservice teachers as well as teacher trainees in post-university teacher training) in Berlin, Germany, with a focus on usability. The results show that this approach proofed usable for lesson planning and offers positive effects for the perception of time and self-reflection.
In this thesis we introduce the concept of the degree of formality. It is directed against a dualistic point of view, which only distinguishes between formal and informal proofs. This dualistic attitude does not respect the differences between the argumentations classified as informal and it is unproductive because the individual potential of the respective argumentation styles cannot be appreciated and remains untapped.
This thesis has two parts. In the first of them we analyse the concept of the degree of formality (including a discussion about the respective benefits for each degree) while in the second we demonstrate its usefulness in three case studies. In the first case study we will repair Haskell B. Curry's view of mathematics, which incidentally is of great importance in the first part of this thesis, in light of the different degrees of formality. In the second case study we delineate how awareness of the different degrees of formality can be used to help students to learn how to prove. Third, we will show how the advantages of proofs of different degrees of formality can be combined by the development of so called tactics having a medium degree of formality. Together the three case studies show that the degrees of formality provide a convincing solution to the problem of untapped potential.