Suche mittels Attribut

Diese Seite stellt eine einfache Suchoberfläche zum Finden von Objekten bereit, die ein Attribut mit einem bestimmten Datenwert enthalten. Andere verfügbare Suchoberflächen sind die Attributsuche sowie der Abfragengenerator.

Liste der Ergebnisse

Vergleich von Strategien zur Behandlung von Inkonsistenz in Beschreibungslogiken + (Dealing with inconsistencies is a very imp … Dealing with inconsistencies is a very important challenge in practical scenarios of ontology use. The aim of this project is to understand, present, and formally compare different approaches to inconsistency in DLs (such as paraconsistent reasoning and reasoning with maximal consistent subontologies).ng with maximal consistent subontologies).)
Finite Herbrand Models for Monadic Clauses with Unary Function Symbols + (Decidability of First Order Logic (FOL) is … Decidability of First Order Logic (FOL) is a key and active research area in logic and computer science. As FOL is undecidable in its general form, a lot of research is focused on finding classes of FOL which are decidable and studying their properties. In this thesis, we work on one such decidable fragment that only allows monadic predicate and function symbols (with the exception of one constant). We also allow just one variable in the formulas.Research in Logic generally does not concentrate on the finiteness of interpretations. Yet, for any realistic and practical knowledge representation purpose we only have finitely many resources to represent the real world. Therefore we focus on finding the finite Herbrand models for the above mentioned class. We also provide a terminating decision procedure for the existence of a finite Herbrand model for this restricted fragment of FOL. In the end we provide some optimizations and variants of the original algorithm for better performance on certain problems.or better performance on certain problems.)
Structural Subsumption Based Similarity Measures: applications with a medical ontology and in image object recognition + (Description Logics (DLs) are a family of l … Description Logics (DLs) are a family of logic-based knowledge representation formalisms, which can be used to develop ontologies in a formally well-founded way. The standard reasoning service of subsumption has proved indispensable in ontology design and maintenance. This checks, relative to the logical definitions in the ontology, whether one concept is more general/specific than another. When no subsumption relationship is identified, however, no information about the two concepts can be given. We introduce a similarity measure based on the structural subsumption algorithm for the DL EL and then generalize this to one for the DL ALEH. The proposed similarity measures compute a numerical degree of similarity between two concept descriptions despite not being in the subsumption relation. In this talk, two application scenarios will be discussed: the first is about new findings in SNOMED CT; whereas the second is the employment of the similarity measure in an image object recognition framework. in an image object recognition framework.)
Uniform Interpolation for Expressive Description Logics + (Description Logics are a family of logics … Description Logics are a family of logics that are used to model ontologies, terminological knowledge bases that are used to represent domain knowledge in a range of areas such as the semantic web, medicine, biology and many more. Uniform interpolation restricts the vocabulary used in an ontology to a specified set of terms, such that information expressible in this vocabulary is preserved. It has potentially many applications, such as in ontology reuse or ontology analysis. The theoretical properties of uniform interpolation in description logics are not encouraging for practical applications: finite representations do not always exist in classical description logics, and the size can be triple exponential with respect to the size of the input already for simpler description logics. We present an approach based on resolution that allows to compute uniform interpolants in various expressive description logics practically in a lot of cases. An evaluation on realistic ontologies shows a high success rate despite the known worst-case complexities.despite the known worst-case complexities.)
Beschreibungslogiken + (Description Logics represent one of today's major paradigms in Knowledge Representation. They have developed out of semantic networks and frame-based approaches.)
Fixed-Domain Reasoning for Description Logics + (Description logics (DLs) are currently a d … Description logics (DLs) are currently a de facto standard in logic-based knowledge representation thanks to the last two decades of research and their use as the underpinning of standardized and widely adopted web ontology language (OWL), which also comes with the ad- vantage of existing user-friendly modeling tools. It has, however, been observed that OWL and description logics (DLs) are utilized by logically less skilled practitioners as constraint languages adopting a closed-world assumption, contrary to the open world semantics imposed by the clas- sical definitions and the standards. Therefore, we came up with an al- ternative formal semantics reflecting this “off-label use” of these widely adopted formalisms. To that end, we introduce the fixed domain seman- tics and discuss that this semantics gives rise to the interesting new inferencing task of model enumeration. We describe how the new seman- tics can be axiomatized in very expressive DLs. We thoroughly investi- gate the complexities for standard reasoning as well as query answering for a wide range of DLs. We present an implementation of a fixed do- main DL reasoner based on the translation into answer set programming (ASP) and provide first results that this tool is superior to alternative approaches when used on constraint-satisfaction-type problems. on constraint-satisfaction-type problems.)
Causality meets Configurable Systems + (Detecting and understanding reasons for de … Detecting and understanding reasons for defects and inadvertent behavior in computing systems is challenging due to increasing complexity of such systems. Configurability adds a further layer of complexity as the number of system variants can be exponential in the number of configuration options. Determining reasons of configuration decisions that yield an effect, e.g., ensuring quality of service, is hence a crucial and difficult task. In this talk, I will present a notion of causality at the level of configuration options and algorithms to compute such causes from (functional and non-functional) analysis results. The presented notion of causality is based on counterfactual reasoning and inspired by the seminal definition of actual causality by Halpern and Pearl. I will present various methods to explicate such reasons for effects, e.g., based on well-established notions of responsibility and blame. By means of an evaluation on a wide range of configurable software systems, including community benchmarks and real-world systems, the feasibility of this approach is demonstrated by identifying root causes, estimate the effects of configuration options, and detect feature interactions. options, and detect feature interactions.)
Tracking False Information Online + (Digital media enables fast sharing of info … Digital media enables fast sharing of information and discussions among users. While this comes with many benefits to today’s society, such as broadening information access, the manner in which information is disseminated also has obvious downsides. Since fast access to information is expected by many users and news outlets are often under financial pressure, speedy access often comes at the expense of accuracy, which leads to misinformation. Moreover, digital media can be misused by campaigns to intentionally spread false information, i.e. disinformation, about events, individuals or governments. In this talk, I will present on different ways false information is spread online, including misinformation and disinformation. I will then report findings from our recent and ongoing work on automatic fact checking, stance detection and framing attitudes.g, stance detection and framing attitudes.)
Aktivitaet2105 + (Director of the School of Embedded Composite AI (SECAI))
Don’t Repeat Yourself: Termination of the Skolem Chase on Disjunctive Existential Rules + (Disjunctive Existential Rules are a fragme … Disjunctive Existential Rules are a fragment of first order logic that is already expressive enough to capture many description logics. Conjunctive Query answering is an important reasoning task over such rules. Although this problem is undecidable, different variants of the chase provide sound and complete algorithms that can be used as a reasoning basis. Since it is undecidable if these algorithms terminate for a specific rule set, sufficient conditions for termination, called acyclicity notions, are introduced. We develop Disjunctive Model Faithful Acyclicity (DMFA) as a novel acyclicity notion for the disjunctive skolem chase variant by using ideas from Model Faithful Acyclicity (MFA) for the non-disjunctive skolem chase and Restricted Model Faithful Acyclicity (RMFA) for the restricted chase. Our research shows that our notion captures MFA and is able give a better approximation for termination on disjunctive existential rules. Acyclicity notions for the restricted chase like RMFA still capture DMFA but these notions are not sound for the disjunctive skolem chase. Our results encourage the use of the disjunctive skolem chase in practical applications, which is implementable using well optimized ASP solvers. Slides available at: https://gitlab.com/m0nstR/defence-grosser-beleg/-/blob/master/build/defence-lukas-gerlach.pdfeg/-/blob/master/build/defence-lukas-gerlach.pdf)
Don’t Repeat Yourself: Termination of the Skolem Chase on Disjunctive Existential Rules + (Disjunctive Existential Rules are a fragme … Disjunctive Existential Rules are a fragment of first order logic that is already expressive enough to capture many description logics. Conjunctive Query answering is an important reasoning task over such rules. Although this problem is undecidable, different variants of the chase provide sound and complete algorithms that can be used as a reasoning basis. Since it is undecidable if these algorithms terminate for a specific rule set, sufficient conditions for termination, called acyclicity notions, are introduced. We develop Disjunctive Model Faithful Acyclicity (DMFA) as a novel acyclicity notion for the disjunctive skolem chase variant by using ideas from Model Faithful Acyclicity (MFA) for the non-disjunctive skolem chase and Restricted Model Faithful Acyclicity (RMFA) for the restricted chase. Our research shows that our notion captures MFA and is able give a better approximation for termination on disjunctive existential rules. Acyclicity notions for the restricted chase like RMFA still capture DMFA but these notions are not sound for the disjunctive skolem chase. Our results encourage the use of the disjunctive skolem chase in practical applications, which is implementable using well optimized ASP solvers.This talk is a defence of the speakers "Großer Beleg".Furthermore it will be held online and take approximately 45 minutes which consist of an uninterrupted talk and a following question and answers part. If there is any interest in attending, please send an e-mail to thomas.feller@tu-dresden.de. an e-mail to thomas.feller@tu-dresden.de.)
Award1012 + (Dr. Anni-Yasmin Turhan received the Georg- … Dr. Anni-Yasmin Turhan received the Georg-Helm Award of the Technische Universität Dresden for her PhD thesis 'On the Computation of Common Subsumers in Description Logics'. Here is a [https://lat.inf.tu-dresden.de/research/GeorgHelmPreis2008.html picture] of the award ceremony.s2008.html picture] of the award ceremony.)
Award1019 + (Dr. Boontawee Suntisrivaraporn is nominate … Dr. Boontawee Suntisrivaraporn is nominated by the faculty for the [https://lat.inf.tu-dresden.de/research/CommerzbankPreisSun.pdf Commerzbank dissertation prize] for his PhD thesis on 'Polynomial-Time Reasoning Support for Design and Maintenance of Large-Scale Biomedical Ontologies'.nce of Large-Scale Biomedical Ontologies'.)
Award1005 + (Dr. Carsten Lutz received the [http://people.kmi.open.ac.uk/marta/papers/ieee2006.pdf 'AI's Ten to Watch'] award of the [https://www.computer.org/web/computingnow/intelligentsystems IEEE Intelligent Systems Magazine].)
Award1018 + (Dr. Rafael Peñaloza received the Best Diss … Dr. Rafael Peñaloza received the Best Dissertation Award from [http://go.sap.com/corporate/en/company/innovation-quality.html SAP Research Center, Dresden] for his PhD thesis on 'Axiom-Pinpointing in Description Logics and Beyond'. Here is a [https://lat.inf.tu-dresden.de/research/SAPPreis2010.html picture] of the award ceremony.s2010.html picture] of the award ceremony.)
Award1006 + (Dr. Sebastian-Philipp Brandt received the … Dr. Sebastian-Philipp Brandt received the Georg-Helm Award of the Technische Universität Dresden for his PhD thesis on 'Standard and Non-standard Reasoning in Description Logics'. Here is a [https://lat.inf.tu-dresden.de/research/GeorgHelmPreis2006.html picture] of the award ceremony.s2006.html picture] of the award ceremony.)
Award1010 + (Dr. Stefan Schulz, Boontawee Suntisrivarap … Dr. Stefan Schulz, Boontawee Suntisrivaraporn and Prof. Franz Baader received one of the three Best Paper Awards (from 900 submissions and 300 presented papers) of the [http://dblp.uni-trier.de/db/conf/medinfo/medinfo2007.html Medinfo 2007 Congress] in Brisbane, Australia in August 2007 for their article 'SNOMED CT's Problem List: Ontologists' and Logicians' Therapy Suggestions'.ists' and Logicians' Therapy Suggestions'.)
Neuer Mitarbeiter: Dr. Stephan Mennicke + (Dr. Stephan Mennicke has joined the [https … Dr. Stephan Mennicke has joined the [https://iccl.inf.tu-dresden.de/web/Wissensbasierte_Systeme/en Knowledge-Based Systems] group in May 2020 as a postdoctoral researcher. Good luck, Stephan! Before joining TU Dresden, Stephan received his PhD in Computer Science from the TU Braunschweig, where he was working as a research assistant. Click [https://iccl.inf.tu-dresden.de/web/Phdthesis3014 here] for more information about his PhD thesis, which is titled "Non-Standard Semantics of Graph Query Languages".on-Standard Semantics of Graph Query Languages".)
Neuer Mitarbeiter: Stefan Ellmauthaler + (Dr. [[Stefan_Ellmauthaler/en|Stefan Ellmauthaler]] … Dr. [[Stefan_Ellmauthaler/en|Stefan Ellmauthaler]] has joined the [[Wissensbasierte Systeme/en|Knowledge-Based Systems]] group in January 2021. For the next few years, he will be working as a postdoc researcher in the group of Prof. Dr. [[Markus Krötzsch]] on the project [[ScaDS.AI]]. Before joining TU Dresden, Stefan received his PhD at the Leipzig University. You can find more information about his research [[Stefan_Ellmauthaler/en|here]]. Good luck, Stefan![Stefan_Ellmauthaler/en|here]]. Good luck, Stefan!)
NAVAS + (Due to the continuous development in recen … Due to the continuous development in recent years, a large number of demanding combinatorial search problems of enormous practical relevance can now be efficiently solved by Answer Set Programming (ASP). Depending on the scope of the problem to be solved, a "combinatorial explosion" of the number of solutions can occur very quickly. While modern ASP solvers can easily calculate several million solutions in a short time, this poses a new problem for the user: How should the enormous solution space be handled and made accessible? Typically, the Answer Sets are output in any order. However, many of these solutions are very similar. In practice, however, often only solutions are of interest that are sufficiently different from each other, that have special properties, or that are similar to a given set of solutions. Such features are not yet supported by ASP solvers. To enable an interactive and transparent navigation in ASP solution spaces the project NAVAS will deal with the following topics:# Development of methods for interactive and transparent navigation in the Answer Set solution space;# Implementation of the methods with efficient algorithms;# Evaluation of the prototype on use cases from the areas of configuration and argumentation theory.We are confident that the knowledge, developments and implementations achieved in NAVAS will make ASP technology more accessible to a wider audience. We see a particular immediate potential in the area of industrial applications, for example product configuration.'''News:'''[https://iccl.inf.tu-dresden.de/web/Sarah_Alice_Gaggl/NAVAS_Workshop-Wien] First NAVAS Workshop in Vienna (23.-24.05.2022)[https://iccl.inf.tu-dresden.de/web/News78] Honorable Mention at LPNMR 2022eb/News78] Honorable Mention at LPNMR 2022)
Big Data in SAT Solving - Heuristiken von Beweisen lernen + (During search SAT Solvers generate a lot o … During search SAT Solvers generate a lot of data, which is usually not used to drive the solvers heuristics. Using this data - in this thesis the unsatisfiability proof - might improve lead to a more efficient search process.In this project the heuristics of a SAT solver should be improved by looking at data that is present in unsatisfiability proofs.hat is present in unsatisfiability proofs.)
EPCL PhD Workshop + (During the PhD workshop, members of each d … During the PhD workshop, members of each doctoral candidate's advisory board will be present to discuss, refine and, if needed, readjust the PhD projects. Other doctoral candidates, researches from the partner universities as well as staff from the associated partners may attend the PhD workshop.The participation in the PhD workshop shall enhance the doctoral candidates' skills to define, implement, and successfully complete a research project. The PhD workshop is organized by the doctoral candidates themselves, thus developing and enhancing their skills to plan, organize, and run scientific events.plan, organize, and run scientific events.)
EPCL PhD Workshop 2012 + (During the PhD workshop, members of each d … During the PhD workshop, members of each doctoral candidate's advisory board will be present to discuss, refine and, if needed, readjust the PhD projects. Other doctoral candidates, researches from the partner universities as well as staff from the associated partners may attend the PhD workshop.The participation in the PhD workshop shall enhance the doctoral candidates' skills to define, implement, and successfully complete a research project. The PhD workshop is organized by the doctoral candidates themselves, thus developing and enhancing their skills to plan, organize, and run scientific events.plan, organize, and run scientific events.)
Sebastian Rudolph erhält ERC Consolidator Grant + (ERC grants, awarded by the European Resear … ERC grants, awarded by the European Research Council (ERC) are among the most prestigious European scientific awards with the purpose of supporting leading scientists in conducting visionary foundational research. Sebastian Rudolph's project "A Grand Unified Theory of Decidability in Logic-Based Knowledge Representation" (DeciGUT) with a duration of five years and a total funding volume of 1.8 Mio € will investigate foundational principles of decidability of query answering over logically specified knowledge. The addressed problem – algorithmic realizability of inference tasks – is of high relevance to diverse scientific fields like mathematical logic, artificial intelligence, and database theory with potentially far-reaching impact in areas such as semantic technologies and information systems.Press release of the ERC: https://erc.europa.eu/news/erc-2017-consolidator-grants-resultsopa.eu/news/erc-2017-consolidator-grants-results)
Aktivitaet2129 + (Editorial Advisor for the journal Theory and Practice of Logic Programming (TPLP))

Aktivitaet2004 + (Editorial board of Kybernetika)

Body-Mind-Language: Embodied Cognition in Natural Language + (Embodied cognition starts from the assumpt … Embodied cognition starts from the assumption that conceptual structure in our minds derives from sensorimotor experiences. Cognitive linguistics has provided compelling evidence that semantic structure in natural language reflects that conceptual structure arising from our embodied experience in the world. Thus, natural language provides an excellent source of knowledge to study embodied cognition. To capture this cognitive conceptual structure, a set of spatio-temporal building blocks called image schemas was introduced by George Lakoff and Mark Johnson. Detecting image schemas in natural language can provide further insights into how we encode embodied experiences in our communication and potentially contribute to research on conceptual understanding and symbol grounding in cognitive systems. However, due to their abstract nature and lack of formalization they are difficult to detect in language. In this talk, I will first briefly introduce the general idea of image schemas, which has been presented to this group before by my co-author Maria Hedblom, and then proceed to machine learning techniques to extract them from multilingual text. Furthermore, I will provide a short overview on existing approaches and our ongoing work on formalizing image schemas.ongoing work on formalizing image schemas.)
Nichtmonotones Schließen + (Entailment in classical logics (e.g. first … Entailment in classical logics (e.g. first-order predicate logic) is ''montone'', that is, if a formula F follows from a set S of formulas, then F also follows from any superset of S.Non-monotonic reasoning is concerned with entailment relations that do not satisfy monotonicity. Such relations can be used to model default assumptions (such as “delivery is free of charge unless stated otherwise”), rules with exceptions (e.g. “birds typically fly, but penguins do not fly”) or priorities between rules (e.g. federal law trumping state law).The research area investigates the formal modelling of various approaches to non-monotonic reasoning, analyses and compares such entailment relations and also deals with implementations and applications, e.g. in knowledge representation, logic programming, legal reasoning, or [[Natural-Language Understanding]].l-Language Understanding]].)
Existenzielle Regeln + (Existential Rules are a knowledge represen … Existential Rules are a knowledge representation formalism used in artificial intelligence and database theory. Their syntactic flexibility enables an easy integration of both semantic knowledge and databases. Syntactically close to Datalog rules, an important distinguishing feature is the possibility to describe individuals whose existence was not originally known, which is of great help for modeling purposes. All these features have motivated an intense research effort on how to query data under such rules. Questions typically tackled with this respect are the following: which query language achieve a good tradeoff between expressivity and complexity? What ensures the decidability of the query answering problem? What is the complexity of specific classes of rules? How to build efficient reasoners?f rules? How to build efficient reasoners?)
Characterization of the Expressivity of Existential Rule Queries + (Existential rules (also known as Datalog+/ … Existential rules (also known as Datalog+/- or tuple-generating dependencies) have been intensively studied in recent years as a prominent formalism in knowledge representation and database systems. We consider them here as a querying formalism, extending classical Datalog, the language of deductive databases. It is well known that the classes of databases recognized by (Boolean) existential rule queries are closed under homomorphisms. Also, due to the existence of a semi-decision procedure (the chase), these database classes are recursively enumerable. We show that, conversely, every homomorphism-closed recursively enumerable query can be expressed as an existential rule query, thus arriving at a precise characterization of existential rules by model-theoretic and computational properties. Although the result is very intuitive, the proof turns out to be non-trivial. This result can be seen as a very expressive counterpart of the prominent Lyndon-Los-Tarski-Theorem characterizing the homomorphism-closed fragment of first-order logic. Notably, our result does not presume the existence of any additional built-in structure on the queried data, such as a linear order on the domain, which is a typical requirement for other characterizations in the spirit of descriptive complexity.This is joint work with Sebastian Rudolph.This is joint work with Sebastian Rudolph.)
Optimierung des logischen Schließens mit existentiellen Regeln durch die Analyse von Abhängigkeiten + (Existential rules are a powerful formalism … Existential rules are a powerful formalism for describing implicit knowledge contained within a knowledge base. Extracting such knowledge can be achieved with the chase, which is a well-known algorithm for computing universal models. This is done by exhaustively calculating the consequences of each given rule. However, the order in which the rules are selected can have a significant impact on the run time of the procedure as well as the number of derived facts. It was discovered in recent work that core-stratified rule sets allow for a selection strategy that is guaranteed to produce so-called core models, which correspond to the smallest possible universal models if they are finite. The strategy is based on considering certain syntactic relationships between the rules called reliances. These indicate whether it is possible for a rule to produce facts used by another or if selecting a rule in the wrong order may introduce redundant facts into the result. In this work, we utilize these reliances to devise rule application strategies that optimize the chase procedure based on the following criteria: First, we try to minimize the number of times rules are applied during the chase, aiming to improve run times. Second, we want to avoid applying rules in a way which introduces redundant facts. The goal here is to minimize the size of the resulting model, ideally producing a core. While it is always possible to derive a core model in core-stratified rule sets, we show situations where our approach is guaranteed to produce cores even if the rule set is not stratified. Moreover, we give a detailed description of the algorithms necessary for detecting a reliance relationship between two given rules as well as prove their correctness. We implement our approach into the rule reasoning engine VLog and evaluate its effectiveness on several knowledge bases used for benchmarking as well as some real-world data sets. We find a significant improvement in the run times for a small portion of the considered knowledge bases and are able to match VLog in the remaining ones.nd are able to match VLog in the remaining ones.)
Capturing Homomorphism-Closed Decidable Queries with Existential Rules + (Existential rules are a very popular ontol … Existential rules are a very popular ontology-mediated query language for which the chase represents a generic computational approach for query answering. It is straightforward that existential rule queries exhibiting chase termination are decidable and can only recognize properties that are preserved under homomorphisms. In this paper, we show the converse: every decidable query that is closed under homomorphism can be expressed by an existential rule set for which the standard chase universally terminates. Membership in this fragment is not decidable, but we show via a diagonalization argument that this is unavoidable.This work has been presented in a relatively short presentation at KR 2021. This extended talk will have room for more in-depth explanations and discussions.The talk is via BigBlueButton, link:https://bbb.tu-dresden.de/b/ali-zgz-l8d-52nttps://bbb.tu-dresden.de/b/ali-zgz-l8d-52n)
Normalisations of Existential Rules: Not so Innocuous! + (Existential rules are an expressive knowle … Existential rules are an expressive knowledge representation language mainly developed to query data. In the literature, they are often supposed to be in some normal form that simplifies technical developments. For instance, a common assumption is that rule heads are atomic, i.e., restricted to a single atom. Such assumptions are considered to be made without loss of generality as long as all sets of rules can be normalised while preserving entailment. However, an important question is whether the properties that ensure the decidability of reasoning are preserved as well. We provide a systematic study of the impact of these procedures on the different chase variants with respect to chase (non-)termination and FO-rewritability. This also leads us to study open problems related to chase termination of independent interest.chase termination of independent interest.)
Reliance-Based Optimization of Existential Rule Reasoning + (Existential rules is a powerful formalism … Existential rules is a powerful formalism for describing implicit knowledge contained within a dataset. Extracting such knowledge can be achieved with the chase, which is a well-known algorithm for computing universal models. This is done by exhaustively calculating the consequences of each given rule. However, the order in which the rules are selected can have a significant impact on the run time of the procedure as well as the number of derived facts. It was discovered in recent work that core-stratified rule sets allow for a selection strategy that is guaranteed to produce so-called core models, which, in the finite case, correspond to the smallest possible universal models. The strategy is based on considering certain syntactic relationships between the rules called reliances. These indicate whether it is possible for a rule to produce facts used by another or if selecting a rule in the wrong order may introduce redundant facts into the result.In this work, we utilize these reliances to devise rule application strategies that optimize the chase procedure based on the following criteria: First, we try to minimize the number of times rules are applied during the chase, aiming to improve run times. Second, we want to avoid applying rules in a way which introduces redundant facts. The goal here is to minimize the size of the resulting model, ideally producing a core. While it is always possible to derive a core model in core-stratified rule sets, we show situations where our approach is guaranteed to produce cores even if the rule set is not stratified. Moreover, we give a detailed description of the algorithms necessary for detecting a reliance relationship between two given rules as well as prove their correctness. We implement our approach into the rule reasoning engine VLog and evaluate its effectiveness on several knowledge bases used for benchmarking as well as some real-world datasets. We find a significant improvement in the run times for a small portion of the considered knowledge bases and are able to match VLog in the remaining ones.This is a diploma defense, the talk is online.Link: https://bbb.tu-dresden.de/b/ali-zgz-l8d-52nttps://bbb.tu-dresden.de/b/ali-zgz-l8d-52n)
Ankündigung: Themenvergabe für studentische Projekte + (Exiting news! On April 25th, in room APB 3 … Exiting news!On April 25th, in room APB 3027, the KBS group will present several student projects Along the different study programs, students from the [https://tu-dresden.de/ing/informatik faculty of computer science] at [https://tu-dresden.de/ TU Dresden] are required to develop projects that would train their habilities and prepare them for their future careers. Each semester the [https://iccl.inf.tu-dresden.de/web/Wissensbasierte_Systeme KBS group] collects and presents several research topics to students looking for projects. Such projects can be used by the students in different modules depending on their study program. "We are looking forward to present our exiting research ideas and to find motivated students willing to participate in our projects and do research with us" [[Markus Krötzsch]] said, when asked about the event.More information can be found at the [https://iccl.inf.tu-dresden.de/web/Projekte_und_Studienarbeiten_Wissensbasierte_Systeme/en projects and thesis page]udienarbeiten_Wissensbasierte_Systeme/en projects and thesis page])
Aktivitaet2064 + (Expert in the Blackmarket for Useful Knowledge and Non-Knowledge)
Reasonable Highly Expressive Query Languages + (Expressive query languages are gaining rel … Expressive query languages are gaining relevance in knowledge representation (KR), and new reasoning problems come to the fore. Especially query containment is interesting in this context. The problem is known to be decidable for many expressive query languages, but exact complexities are often missing. We introduce a new query language, guarded queries (GQ), which generalizes most known languages where query containment is decidable. GQs can be nested (more expressive), or restricted to linear recursion (less expressive). Our comprehensive analysis of the computational properties and expressiveness of (linear/nested) GQs also yields insights on many previous languages.ields insights on many previous languages.)
Award1017 + (Felix Distel received the best paper award … Felix Distel received the best paper award of the [http://w3.uqo.ca/icfca10/ 8th International Conference on Formal Concept Analysis] (ICFCA 2010) in Agadir, Morocco in March 2010 for his paper on 'Complexity of Enumerating Pseudo-Intents in the Lectic Order'.ating Pseudo-Intents in the Lectic Order'.)
Characterizing common argumentation semantics using branch evaluations for justification systems + (First introduced in 2015 by Denecker, Brew … First introduced in 2015 by Denecker, Brewka and Strass, justification theory is formalism providing a new way of characterizing semantics for both logic programs and Dung style argumentation frameworks. Justification theory uses branch evaluation functions operating on a body of rules and an interpretation to define a set of justified facts. Fixpoints of the branch evaluation function on a given body of rules are called justified interpretations. Common semantics for argumentation frameworks can be obtained using these justified interpretations. In this work we characterize these semantics using branch evaluations with the goal of characterizing exactly the desired semantics with no additional conditions imposed on the justified interpretations.We present a grounded branch evaluation yielding grounded semantics for argumentation. This grounded branch evaluation coincides with the branch evaluations providing well founded and Kripke-Kleene semantics for logic programming. Furthermore we show that for admissible, preferred and stable argumentation semantics an exact characterization in the general case is not possible.ation in the general case is not possible.)
CACM-Blogartikel über die Vereinbarkeit von Familie und Beruf im akademischen Umfeld von ICCL-Forscherin Luisa Herrmann + (Following up on her keynote at this year's … Following up on her keynote at this year's Logic Mentoring Workshop ([https://logic-mentoring-workshop.github.io/csl24/ LMW 2024]), our colleague [[Luisa Herrmann]], member of the [[Computational Logic]] group and [https://scads.ai/ ScaDS.AI] was invited to summarize her reflections on this vital subject for the blog of [https://cacm.acm.org/ Communications of the ACM], the leading online and print publication for the computing and information technology fields. We feel that raising awareness of this topic is crucial in our ongoing pursuit for gender equality and family-friendliness at academic institutions.ily-friendliness at academic institutions.)
On the Complexity of k-Piecewise Testability and the Depth of Automata + (For a non-negative integer k, a language i … For a non-negative integer k, a language is k-piecewise testable (k-PT) if it is a finite boolean combination of languages of the form \Sigma^*a1\Sigma^*...\Sigma^*an for ai in \Sigma and 0 <= n <= k. We study the following problem: Given a DFA recognizing a piecewise testable language, decide whether the language is k-PT. We provide a complexity bound on this problem and a detailed analysis for small k's. The result can be use to find the minimal k for which the language is k-PT. We show that the upper bound on k given by the depth of the minimal DFA can be exponentially bigger than the minimal possible k, and provide a tight upper bound on the depth of the minimal DFA recognizing a k-PT language.Joint work with [[Michaël Thomazo]][[Michaël Thomazo]])
Lehr- und Prüfungsbetrieb während der COVID-19 Pandemie + (For more information on how to conduct exa … For more information on how to conduct examinations and teaching during the COVID-19 pandemic, see the following links: <ul> <li>[https://tu-dresden.de/ing/informatik/studium/news/covid19-lehr-und-pruefungsbetrieb-an-der-fakultaet-informatik COVID19: Teaching and examinations at the faculty of computer science]</li> <li>[https://tu-dresden.de/studium/im-studium/coronavirus/ Teaching and learning during the COVID-19 pandemic]</li></ul>um/coronavirus/ Teaching and learning during the COVID-19 pandemic]</li> </ul>)
SEMECO-Q1 + (For more information, see the [https://digitalhealth.tu-dresden.de/projects/semeco/ external project website].)
Detecting Non-Existence of Finite Universal Models for Existential Rules + (For reasoning over ontologies, (finite) un … For reasoning over ontologies, (finite) universal models play an important role in tasks like conjunctive query answering, which is undecidable. The (restricted) chase is a sound and complete algorithm for computing (finite) universal models of ontologies featuring existential rules. Termination of the chase is undecidable and various sufficient conditions for termination and non-termination have been studied. If the chase terminates, we obtain a finite universal model. However, if the chase does not terminate, a finite universal model may still exist. In recent work, it has been shown that for certain ontologies for which the chase terminates, there exists a chase sequence that yields a universal model that is a core and therefore is the smallest universal model for the given rule set up to isomorphism. We extend this result to non-terminating chase sequences. By that, we are able to introduce a sufficient condition for the existence of an infinite universal model that is a core which in turn implies that no finite universal model exists.Note that this talk acts as a colloquium/examination for the module INF-PM-FPG. It will take place online via BigBlueButton. To access the room, take one of the following links: with ZIH-login:https://selfservice.zih.tu-dresden.de/l/link.php?m=86971&p=30896df0without ZIH-login:https://selfservice.zih.tu-dresden.de/link.php?m=86971&p=83001746.zih.tu-dresden.de/link.php?m=86971&p=83001746)
ICCL von der TU Dresden als Leuchtturm ausgewählt + (For the first time, and in order to recogn … For the first time, and in order to recognize and promote international presence of the TU Dresden, the International Affairs Commission has distinguished 22 associated organizations as shining examples of internationalization and granted them the status of international lighthouses.Among these organizations, the ICCL gained such recognition in the "Local network with international radiance" category due to its outstanding international research impact. We congratulate all people who make this recognition possible, and hope that ICCL continues as an example of internationalization.More information [https://tu-dresden.de/tu-dresden/internationales/dezentrale-partnerschaften-netzwerke-und-programme?set_language=en here]zwerke-und-programme?set_language=en here])
Visualization and navigation paradigms for triadic formal concept analysis + (Formal Concept Analysis (FCA) is a mathema … Formal Concept Analysis (FCA) is a mathematical discipline that describes conceptual hierarchies arising from a binary incidence structures (so-called formal contexts) in terms of lattice theory. In a concept lattice, formal concepts are ordered by subconcept-superconcept relationship, giving rise to very intuitive ways of visualizing and navigating data sets. FCA has become an extremely active and important field of research having made impressive progress over the last years.This research focuses on Triadic FCA, an extension of “classical” FCA considering ternary incidence structures (tricontexts with objects, attributes and conditions) giving rise to so-called triconcepts. Although such ternary incidence structures arise naturally in diverse data analysis settings, the structure of the corresponding trilattices is still not so well-understood and previous attempts to develop intuitive visualizations have led to unsatisfactory results. This presentation aims to introduce new ideas for a visualization and navigation framework that enable human users to explore and interact with triadic data sets in an intuitive and natural manner.a sets in an intuitive and natural manner.)
Membership Constraints in Formal Concept Analysis + (Formal Concept Analysis (FCA) is a promine … Formal Concept Analysis (FCA) is a prominent field of applied mathematics using object-attribute relationships to define formal concepts — groups of objects with common attributes — which can be ordered into conceptual hierarchies, so-called concept lattices. We consider the problem of satisfiability of membership constraints, i.e., to determine if a formal concept exists whose object and attribute set include certain elements and exclude others. We analyze the computational complexity of this problem in general and for restricted forms of membership constraints. We perform the same analysis for generalizations of FCA to incidence structures of arity three (objects, attributes and conditions) and higher. We present a generic answer set programming (ASP) encoding of the membership constraint satisfaction problem, which allows for deploying available highly optimized ASP tools for its solution. Finally, we discuss the importance of membership constraints in the context of navigational approaches to data analysis.This talk is based on joint work with Diana Troancă.is based on joint work with Diana Troancă.)
Formale Begriffsanalyse + (Formal Concept Analysis is a mathematical … Formal Concept Analysis is a mathematical theory which describes concepts and conceptual hierarchies by means of lattice theory. Thereby, the basis are ''formal contexts'', elementary data structures that describe objects and their attributes. A ''formal concept'' is then composed of a set of objects and a set of attributes which -- in line with philosophical and linguistic traditions -- are called ''concept extent'' and ''concept intent'', respectively. Formal concepts can then be put into relation to each other, forming a hierarchy of sub- and superconcepts.Formal Concept Analysis was founded in the 1980s in Darmstadt in the group of Rudolf Wille and has become a discipline with numerous practical applications in diverse areas, including data- and textmining, [[Wissensrepräsentation und logisches Schließen/en|knowledge management]], [[Semantische Technologien/en|Semantic Web]], software engineering, economics or biology.oftware engineering, economics or biology.)
Metamodellierung in der Formalen Begriffsanalyse + (Formal Concept Analysis starts from a very … Formal Concept Analysis starts from a very basic data structure comprising objects and their attributes. Sometimes, however, it is benefitial to also define attributes of attributes (so-called meta attributes). The general goal of this project is to develop a framework for this kind of Meta-Modelling in FCA, including formal definitions and appropriate visualizations.efinitions and appropriate visualizations.)
Automatic and Interactive Search in Flexible Dispute Derivations for Assumption-Based Argumentation + (Formal argumentation (FA) is a branch of k … Formal argumentation (FA) is a branch of knowledge representation and reasoning in artificial intelligence, which offers ways of resolving potential conflicts within a knowledge base and inferring which claims can be trusted. FA can be further divided between abstract- and structured argumentation, with the first one treating arguments as atomic entities and the latter allowing to further investigate their internal structure. Assumption-based argumentation (ABA) is one of the main general structured argumentation frameworks, in which dispute derivations (DDs) are methods for determining the acceptance of claims in dialectical manner. With DDs arguments and counter-arguments are constructed interchangeably between, as can be conceived, two fictitious players – the proponent and the opponent of a set of claims under scrutiny.Among the many formalisations of DDs for ABA, which have been proposed throughout the past decades, flexible dispute derivations (FlexDDs) are the latest. FlexDDs offer a number of solutions unprecedented in the former versions, including reusing one player’s arguments by the other player or support for complete and stable argumentation semantics to name a few. Most notably however, alongside the regular, backward, top-down reasoning from claims to premises they also allow for construction of forward, bottom-up arguments, from premises to claims. Moreover, FlexDDs comes in two versions – a more high-level and abstract argument-based version as well as a more concrete and implementation-focused rule-based version.In this thesis we focus on automatized search of successful dispute derivations for flexible dispute derivations. We devise procedures and examine the properties of strategies tailored for specific semantics, with the aim of isolating features impacting the efficiency, among other concerns.Furthermore, we investigate the influence of forward reasoning on the performance of the search procedures.We have performed a thorough empirical evaluation, the results of which are presented and interpreted, to back up our claims and hypotheses. Moreover, our implementation for FlexDDs has been significantly extended, currently capable of following the defined search strategies in an automatic search for successful DDs as well as having rich support for interactive reasoning, besides many other notable features which we report on in this work. features which we report on in this work.)
Conceptual Visualization and Navigation Methods for Polyadic Formal Concept Analysis + (Formal concept analysis (FCA) is the core … Formal concept analysis (FCA) is the core of Conceptual Knowledge Processing, being closely related to a deeper understanding of existing facts and relationships, while at the same time trying to find explanations for their existence. Polyadic formal concept analysis is an extension of classical FCA that instead of binary relations uses an n-ary incidence relation to define formal concepts, i.e. data clusters in which all elements are interrelated. In this thesis, we introduce new methods of visualization, navigation and exploration based on polyadic formal concept analysis for n-adic datasets with n = 3. In the first part, we introduce a triadic approach to study the Web usage behavior of an e-learning platform. We analyze temporal aspects of the users' behavior and visualize the results in a circular layout using the Circos tool. In the subsequent chapter, we define methods to reduce the size of a triadic dataset without altering its underlying structure. For this purpose, we extend the notions of clarification and reduction from the dyadic to the triadic setting and show that these processes have an influence solely on the efficiency and not on the results of any further analysis. Next, we introduce a navigation paradigm based on a reachability relation among formal concepts. This relation gives rise to so-called reachability clusters containing mutually reachable concepts. We discuss theoretical aspects about the properties of the formal concepts arising from the defined reachability relation and describe the framework of the proposed navigation paradigm. Subsequently, we consider the problem of satisfiability of membership constraints in order to determine if a formal concept exists whose components include and exclude certain elements. We analyze the computational complexity of this problem for particular cases as well as for the general n-adic problem and present an answer set programming encoding for the membership constraint satisfaction problem. Next, we propose a navigation paradigm based on membership constraints and implement it for the dyadic, triadic and tetradic case using different strategies, one based on the proposed ASP encoding and one using an exhaustive search in the whole concept set, precomputed with an external FCA tool. We evaluate and compare the implementations and discuss the limitations and the possibility of generalizations of each approach. In the final part of the thesis, we describe the achievements of our research as well as possible directions for future work.ll as possible directions for future work.)