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Liste der Ergebnisse

Raum APB 3105 + (Dies ist der ovale Besprechungsraum in der dritten Etage des Andreas-Pfitzmann-Bau.)
Raum SCH A252 + (Dies ist ein Seminarraum im Georg-Schumann-Bau. Er enthält etwa 30 Sitzplätze.)
Raum APB E005 + (Dies ist einer der Seminarräume im Erdgeschoss des Andreas-Pfitzmann-Baus. Er enthält etwa 30 Sitzplätze und mehrere große Kreidetafeln.)
Raum APB E007 + (Dies ist einer der Seminarräume im Erdgeschoss des Andreas-Pfitzmann-Baus. Er enthält etwa 30 Sitzplätze und mehrere große Kreidetafeln.)
Raum APB E009 + (Dies ist einer der Seminarräume im Erdgeschoss des Andreas-Pfitzmann-Baus. Er enthält etwa 30 Sitzplätze und mehrere große Kreidetafeln.)
Raum APB E010 + (Dies ist einer der Seminarräume im Erdgeschoss des Andreas-Pfitzmann-Baus. Er enthält etwa 30 Sitzplätze und mehrere große Kreidetafeln.)
Raum REC C118 + (Dies ist einer der Seminarräume im ersten Obergeschoss des Recknagel-Baus. Er enthält etwa 30 Sitzplätze und mehrere Kreidetafeln sowie einen Beamer.)
Raum APB E008 + (Dies ist einer der kleineren Seminarräume im Erdgeschoss des Andreas-Pfitzmann-Baus. Er enthält etwa 30 Sitzplätze.)
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 der 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 ist seit Mai 2020 neu … Dr. Stephan Mennicke ist seit Mai 2020 neues Mitglied der Gruppe für [https://iccl.inf.tu-dresden.de/web/Wissensbasierte_Systeme Wissensbasierte Systeme]. Er wird als Postdoktorand mit der Gruppe von Prof. Markus Krötzsch forschen. Viel Erfolg, Stephan! Vor seiner Zeit an der TU Dresden wurde Stephan an der TU Braunschweig promoviert. Dort war er ebenfalls als wissenschaftlicher Mitarbeiter tätig. Seine [https://iccl.inf.tu-dresden.de/web/Phdthesis3014 Arbeit] deckt Nichtstandardsemantiken von Graphanfragesprachen ab.tstandardsemantiken von Graphanfragesprachen ab.)
Markus Krötzsch erhält wichtigsten deutschen Nachwuchspreis + (Dr. [[Markus Krötzsch/en|Markus Krötzsch]] v … Dr. [[Markus Krötzsch/en|Markus Krötzsch]] vom Institut für Theoretische Informatik wird mit dem [http://www.dfg.de/foerderung/programme/preise/leibnitz-preis/ Heinz Maier-Leibnitz-Preis] 2016 der Deutschen Forschungsgemeinschaft (DFG) und des Bundesministeriums für Bildung und Forschung (BMBF) ausgezeichnet. Der Heinz Maier-Leibnitz-Preis, benannt nach dem Atomphysiker und früheren DFG-Präsidenten, wird seit 1977 jährlich an hervorragende junge Forscher verliehen. Er gilt als der wichtigste seiner Art für den Forschernachwuchs in Deutschland. Für die diesjährige Preisrunde waren insgesamt 134 Wissenschaftler aus allen Fachgebieten vorgeschlagen worden. Zehn von ihnen erhalten die mit jeweils 20.000 Euro dotierte Auszeichnung in einer offiziellen Verleihung am 18. Mai 2016 in Berlin.Markus Krötzsch wird ausgezeichnet für seine Arbeiten auf dem Gebiet der [[Wissensrepräsentation und logisches Schließen|Wissensrepräsentation]], welches sich mit der maschinenlesbaren Darstellung und der intelligenten automatischen Verarbeitung menschlichen Wissens durch den Computer beschäftigt. Diese Basistechnologie ermöglicht die intelligente Handhabung großer und komplexer Daten in vielfältigen Anwendungsgebieten. Die Forschung in der Wissensrepräsentation befasst sich mit den formalen Grundlagen, der Entwicklung und Optimierung von Softwaresystemen sowie der Anwendung dieser Systeme. Unter anderem würdigte die Auswahlkommission auch Krötzschs Beitrag zur Schaffung von [[Wikidata]], einer „Wikipedia der Daten“, die Wikipedia-Ausgaben in allen Sprachen mit Daten versorgt, welche bereits in Millionen von Artikeln sichtbar sind.Mit dem Preisträger freuen sich neben dem [[ICCL]] und der [http://www.inf.tu-dresden.de/ Fakultät Informatik] auch das Exzellenzcluster [https://www.cfaed.tu-dresden.de/ cfaed] und der Sonderforschungsbereich [[HAEC]], mit denen Krötzsch eng verbunden ist. Die TU Dresden kann sich in diesem Jahr zudem über einen weiteren Maier-Leibnitz-Preisträger freuen: [https://tu-dresden.de/die_tu_dresden/fakultaeten/philosophische_fakultaet/ig/age/mitarbeiter/Lundgreen Christoph Lundgreen] vom Lehrstuhl für Alte Geschichte erhält ebenfalls einen der begehrten Preise.hält ebenfalls einen der begehrten Preise.)
Neuer Mitarbeiter: Stefan Ellmauthaler + (Dr. [[Stefan_Ellmauthaler|Stefan Ellmauthaler]] … Dr. [[Stefan_Ellmauthaler|Stefan Ellmauthaler]] ist seit Januar 2021 in der Gruppe [[Wissensbasierte Systeme]] tätig. Für die nächsten Jahre wird er als Postdoc in der Gruppe von Prof. Dr. [[Markus Krötzsch]] am Projekt [[ScaDS.AI]] arbeiten. Vor seinem Eintritt an die TU Dresden promovierte Stefan an der Universität Leipzig. Weitere Informationen zu seiner Forschung finden Sie [[Stefan_Ellmauthaler|hier]]. Viel Glück, Stefan!fan_Ellmauthaler|hier]]. Viel Glück, Stefan!)
NAVAS + (Durch die kontinuierliche Weiterentwicklun … Durch die kontinuierliche Weiterentwicklung in den letzten Jahren können heute eine Vielzahl anspruchsvoller kombinatorischer Suchprobleme von enormer praktischer Relevanz effizient durch Answer Set Programming (ASP) gelöst werden. Dabei kann es je nach Umfang des zu lösenden Problems sehr rasch zu einer “kombinatorischen Explosion” der Menge von Lösungen kommen. Während moderne ASP Solver problemlos mehrere Millionen von Lösungen in kurzer Zeit berechnen können, stellt dies den Anwender vor ein neues Problem: Wie soll der enorme Lösungsraum gehandhabt und zugänglich gemacht werden?Typischer Weise werden die Answer Sets in beliebiger Reihenfolge ausgegeben. Jedoch sind viele dieser Lösungen sehr ähnlich. In der Praxis sind hingegen oft nur Lösungen von Interesse, die sich hinreichend voneinander unterscheiden, die besondere Eigenschaften aufweisen, oder die einer gegebenen Menge von Lösungen ähnlich sind. Derlei Features werden allerdings bis jetzt noch nicht von ASP Solvern unterstützt.Um eine interaktive und transparente Navigation in ASP-Lösungsräumen zu ermöglichen wird sich das Projekt NAVAS mit den folgenden Themen befassen:# Entwicklung von Methoden zur interaktiven und transparenten Navigation im Lösungsraum der Answer Sets; # Implementierung der Methoden mit effizienten Algorithmen; # Evaluation des Prototyps anhand von Anwendungsfällen aus den Bereichen Konfiguration und Argumentation. Wir sind zuversichtlich, dass ASP-Technologie durch die in NAVAS erzielten Erkenntnisse, Entwicklungen und Implementierungen auch für eine breitere Masse zugänglicher wird. Hierbei sehen wir ein besonderes unmittelbares Potential im Bereich industrieller Anwendungen, etwa zur Produktkonfiguration.'''News:'''[https://iccl.inf.tu-dresden.de/web/Sarah_Alice_Gaggl/NAVAS_Workshop-Wien] Erster NAVAS Workshop in Wien (23.-24.05.2022)[https://iccl.inf.tu-dresden.de/web/News78] Honorable Mention bei LPNMR 2022b/News78] Honorable Mention bei LPNMR 2022)
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.)
Aktivitaet2129 + (Editorial Advisor für das Journal Theory and Practice of Logic Programming (TPLP))

Aktivitaet2004 + (Editorial Board von 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.)
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.)
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)
Existenzielle Regeln + (Existenzielle Regeln sind ein Formalismus … Existenzielle Regeln sind ein Formalismus zur Wissensrepräsentation mit Anwendungen in der künstlichen Intelligenz und Datenbanken. Ihre syntaktische Allgemeinheit erlauben eine Integration von Formalismen aus der Wissensrepräsentation und aus dem Datenbankbereich. Syntaktisch sind existenzielle Regeln verwandt mit Datalog; ihre wesentliche zusätzliche Ausdrucksstärke besteht in der Möglichkeit, die Existenz von Domänenelementen zu beschreiben, die nicht von vornherein namentlich bekannt sind. Existenzielle Regeln, sind seit längerem unter verschiedenen Bezeichnungen bekannt und die Beantwortung von Anfragen an Daten unter Einbeziehung von existenziellen Regeln ist zur Zeit Gegenstand intensiver Forschung. Typische Fragestellungen hierbei sind beispielsweise: Welche Fragmente existenzieller Regeln verbinden hohe Ausdrucksstärke mit geringer Berechnungsaufwand? Welche allgemeinen Prinzipien garantieren die Entscheidbarkeit der Anfragebeantwortung? Was sind die spezifischen Komplexitäten konkreter Fragmente? Wie entwickelt man effiziente Softwaretools für diese Aufgaben?fiziente Softwaretools für diese Aufgaben?)
Aktivitaet2064 + (Expertin beim Schwarzmarkt für Nützliches Wissen und Nicht-Wissen Nr. 22)
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.)
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]])
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)
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.)
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.)
Metamodellierung in der Formalen Begriffsanalyse + (Formale Begriffsanalyse geht von einer seh … Formale Begriffsanalyse geht von einer sehr grundlegenden Datenstruktur aus, welche Gegenstände und Merkmale in Beziehung setzt. Manchmal ist es allerdings sinnvoll, darüber hinaus Merkmale von Merkmalen (sogenannte Metamerkmale) zu definieren. Das Ziel dieses Projektes besteht darin, ein Framework für Metamodellierung in der FBA zu entwickeln, einschließlich formaler Definitionen und angemessener Visualisierungen.itionen und angemessener Visualisierungen.)
Happy World Logic Day 2021! + (Formale Logik ist für die Informatik das, … Formale Logik ist für die Informatik das, was die Analysis für die Ingenieurswissenschaften darstellt. Logik hat sich als nützliches Werkzeug in der künstlichen Intelligenz (KI), der Haltung und Verwaltung großer Datenmengen, der Analyse und Entwicklung zuverlässiger Systeme, und vielen anderen Themengebieten herausgestellt. Bei uns am ICCL ist Logik zentraler Forschungsgegenstand, z.B. bei [[Wissensrepräsentation_und_logisches_Schließen|der Wissensrepräsentation und dem logischen Schließen]], der Entwicklung [[Semantische_Technologien|semantischer Technologien]] und [[Abstrakte_Argumentation|der abstrakten Argumentation]].Mit der wachsenden Wahrnehmung der Bedeutung von Logik für Wissenschaft und Gesellschaft, hat die [https://unesco.org/ UNESCO] gemeinsam mit der [http://www.icphs.org/ ICPHS] den '''World Logic Day''' ins Leben gerufen, der jährlich am 14. Januar zelebriert wird. Dabei steht die Erhöhung der Sichtbarkeit dieses wichtigen Teilgebiets der Mathematik, Philosophie, der Ingenieurswissenschaften sowie der Informatik im Vordergrund.Die TU Dresden stellt hier einen Vorreiter bei der Erreichung dieses Ziels dar. Schon seit dem Jahr 1997 können hier internationale Studierende ihren Masterabschluss im Studiengang ''Computational Logic'' erreichen. In über zwanzig Jahre haben in diesem Studiengang eine Vielzahl an Modulen die Rolle der Logik in der Informatik hervorgehoben. Seit dem vergangenen Jahr hat die '''[[Logical Modeling/en|logische Modellierung]]''' diese Themen in dem neuen internationalen und interdisziplinären Master-Studiengang ''[https://tu-dresden.de/ing/informatik/studium/studienangebot/master-studiengaenge/computational-modeling-and-simulation/uebersichtsseite Computational Modeling and Simulation]'' übernommen.Das ICCL wünscht allen Studierenden, Forschenden sowie Anwendern der Logik einen frohen World Logic Day 2021!r Logik einen frohen World Logic Day 2021!)
Most Probable Explanations for Probabilistic Database Queries + (Forming the foundations of large-scale kno … Forming the foundations of large-scale knowledge bases, probabilistic databases have been widely studied in the literature. In particular, probabilistic query evaluation has been investigated intensively as a central inference mechanism. However, despite its power, query evaluation alone cannot extract all the relevant information encompassed in large-scale knowledge bases. To exploit this potential, we study two inference tasks; namely finding the most probable database and the most probable hypothesis for a given query. As natural counterparts of most probable explanations (MPE) and maximum a posteriori hypotheses (MAP) in probabilistic graphical models, they can be used in a variety of applications that involve prediction or diagnosis tasks. We investigate these problems relative to a variety of query languages, ranging from conjunctive queries to ontology-mediated queries, and provide a detailed complexity analysis.nd provide a detailed complexity analysis.)
Gruppe Wissensbasierte Systeme erhält Best Paper Award der International Semantic Web Conference + (Forscher der Professur [[Wissensbasierte Systeme]] … Forscher der Professur [[Wissensbasierte Systeme]] haben auf der 17. International Semantic Web Conference (ISWC) in Monterey, Kalifornien den Best Paper Award im "In Use" Track gewonnen. Ihre Arbeit "[[Inproceedings3044|Getting the Most out of Wikidata: Semantic Technology Usage in Wikipedia’s Knowledge Graph]]" beschreibt, wie Informationen aus Wikipedias Schwesterprojekt [[Wikidata]] mit Hilfe einer Graph-Datenbank besser zugreifbar gemacht werden konnten. Der zu diesem Zweck angebotene öffentliche Anfragedienst wurde in 2015 unter Mitarbeit von [[Markus Krötzsch|Prof. Dr. Markus Krötzsch]] entwickelt und wird inzwischen intensiv genutzt: Monatlich werden mehr als 100 Millionen Anfragen beantwortet. Dadurch ermöglicht der Dienst eine Vielfalt von Anwendungen, von leicht bedienbaren mobilen Apps bis zu komplexen Datenanalysen. Betrieben wird der Anfragedienst von der Wikimedia Foundation, welche auch Wikipedia und Wikidata hostet, und mit der die Dresdner Forscher eng zusammenarbeiten.Das Dresdner Team, das neben Professor Krötzsch noch [[Adrian Bielefeldt]], [[Julius Gonsior]] und [[Larry González]] umfasst, interessierte sich auch dafür, was genau hinter den Millionen von Anfragen steckt. Dazu untersuchten Sie deren genaue Struktur und inhaltliche Ausrichtung und gewannen Erkenntnisse zur Verwendung der zugrundeliegenden Datenbankanfragesprache SPARQL, die zur Teil stark von bisherigen Annahmen abweichen. Nach einer umfangreichen Anonymisierung konnten die ausgewerteten Anfragen zudem auch anderen Forschern frei zugänglich gemacht werden. Unterstützt wurde die Arbeit durch den Dresdner [[HAEC|Sonderforschungsbereich 912 "HAEC"]], wo die Ergebnisse in die Entwicklung energieeffizienter Graph-Datenbanken einfließen.Die International Semantic Web Conference ist die führende internationale Zusammenkunft im Bereich semantischer Technologien und Wissensgraphen. Die jährlich stattfindende Veranstaltung ist ein Forum für aktuelle Grundlagenforschung, neuartige Anwendungen und Ressourcen (Datensätze, Software). In jedem der drei Bereiche wurde je ein Best Paper Award vergeben. Aus den insgesamt 254 Einreichungen wurden in diesem Jahr 62 akzeptiert (24%). Die Konferenz wird im kommenden Jahr in Auckland, Neuseeland, stattfinden.* Wikidata Anfragdienst: https://query.wikidata.org/* Veröffentlichte Datensätze von Anfragen: https://kbs.inf.tu-dresden.de/WikidataSPARQL* Sonderforschungsbereich HAEC: https://tu-dresden.de/ing/forschung/sfb912https://tu-dresden.de/ing/forschung/sfb912)
ICCL-Forschende mit Distinguished Paper Award geehrt + (Forscher:innen des [https://iccl.inf.tu-dr … Forscher:innen des [https://iccl.inf.tu-dresden.de/ International Center for Computational Logic] (ICCL) der [https://tu-dresden.de/ TU Dresden] wurden mit dem Harol Boley Distinguished Paper Award auf der diesjährigen [https://2023.declarativeai.net/events/ruleml-rr RuleML+RR] Konferenz ausgezeichnet. Auf der [https://2023.declarativeai.net/events/ruleml-rr International Joint Conference on Rules and Reasoning] (RuleML+RR) treffen sich jedes Jahr führende Experten:innen auf dem Gebiet der regelbasierten Logik. Die Konferenz bietet damit eine gemeinsame Plattform für Foscher:innen sowie Fachleuten aus der Industrie, sich über die neusten Entwicklungen und Ideen in diesem Gebiet auszutauschen. Das mit dem Award ausgezeichnete Paper "Combining Proofs for Description Logic and Concrete Domain Reasoning" von [https://iccl.inf.tu-dresden.de/web/Christian_Al-Rabbaa Christian Alrabbaa], [[Franz Baader]], [[Stefan Borgwardt]], [https://research.vu.nl/en/persons/patrick-koopmann Patrick Koopmann] und [https://lat.inf.tu-dresden.de/~alisa/ Alisa Kovtunova] befasst sich mit Methoden, um Beweise für die von DL-Reasonern abgeleiteten Fakten möglichst benutzerfreundlich darzustellen. Diese herausragende Leistung demonstriert das Engagement des Instituts, zukunftsweisende Forschung in den Bereichen künstliche Intelligenz und Wissensrepräsentation voranzutreiben.n künstliche Intelligenz und Wissensrepräsentation voranzutreiben.)
Algebra und Diskrete Strukturen + (Forschungsgruppe am [https://tu-dresden.de … Forschungsgruppe am [https://tu-dresden.de/mn/math/algebra?set_language=de Institut für Algebra] an der [https://tu-dresden.de/mn/math?set_language=de Fakultät Mathematik] der [https://tu-dresden.de/?set_language=de TU Dresden].Fields of Interest:* Constraint satisfaction problems: algorithms and complexity* Universal algebra, clones on infinite domains, infinite permutation groups* Finite model theory and descriptive complexity* Classical model theory, homogeneous structures, structural Ramsey theory* Enumerative combinatorics Ramsey theory * Enumerative combinatorics)
Second Workshop on Human Reasoning and Computational Logic + (From the 10th to the 12th of April 2018, w … From the 10th to the 12th of April 2018, we organize the second workshop on Human Reasoning and Computational Logic at TU Dresden, Germany. The goal of this workshop is to provide a platform for the scientific exchange with respect to Human Reasoning between the areas of Cognitive Science and Computational Logic.Cognitive Science and Computational Logic.)
Third Workshop on Human Reasoning and Computational Logic + (From the 4th to the 5th of April 2019, we … From the 4th to the 5th of April 2019, we organize the third workshop on Human Reasoning and Computational Logic at TU Dresden, Germany. The goal of this workshop is to provide a platform for the scientific exchange with respect to Human Reasoning between the areas of Cognitive Science and Computational Logic.Cognitive Science and Computational Logic.)
Employing DL-Lite reasoners for fuzzy query answering: Take a FLite! + (Fuzzy Description Logics generalize crisp … Fuzzy Description Logics generalize crisp ones by providing membership degree semantics for concepts and roles by fuzzy sets. Recently, answering of conjunctive queries has been investigated and implemented in optimized reasoner systems based on the rewriting approach for crisp DLs. In this talk we investigate how to employ such existing implementations for query answering in DL-Lite_R over fuzzy ontologies. To this end we give an extended rewriting algorithm for the case of fuzzy DL-Lite_R-ABoxes that employs the one for crisp DL-Lite_R and investigate the limitations of this approach. We also tested the performance of our proto-type implementation FLite of this method.-type implementation FLite of this method.)