Форум: Проблемы искусственного интеллекта

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Автор	Тема: На: Ai Drew :: IJCAI 09 :: Междунар. ии конфа: Позднее лето-2009 - Коротко о Главном
Capt.Drew Сообщений: 4179	На: Ai Drew :: IJCAI 09 :: Междунар. ии конфа: Позднее лето-2009 - Коротко о Главном Добавлено: 21 авг 09 7:05 PART-3: KNOWLEDGE REPRESENTATION, REASONING, and LOGIC: =142=> 0830p Forgetting & Uniform Interpolation in Large-Scale Description Logic Terminologies, Boris Konev, Dirk Walther, Frank Wolter, http://ijcai.org/papers09/Abstracts/142.html We develop a framework for forgetting concepts and roles (aka uniform interpolation) in terminologies in the lightweight description logic EL extended with role inclusions and domain and range restrictions. Three different notions of forgetting, preserving, respectively, concept inclusions, concept instances, and answers to conjunctive queries, with corresponding languages for uniform interpolants are investigated. Experiments based on SNOMED CT (Systematised Nomenclature of Medicine Clinical Terms) and NCI (National Cancer Institute Ontology) demonstrate that forgetting is often feasible in practice for large-scale terminologies. text: http://ijcai.org/papers09/Papers/IJCAI09-142.pdf [Ответ][Цитата]
Capt.Drew Сообщений: 4179	На: Ai Drew :: IJCAI 09 :: Междунар. ии конфа: Позднее лето-2009 - Коротко о Главном Добавлено: 21 авг 09 7:05 PART-3: KNOWLEDGE REPRESENTATION, REASONING, and LOGIC: =143=> 0836p Minimal Module Extraction from DL-Lite Ontologies using QBF Solvers, Roman Kontchakov, Luca Pulina, U.Sattler, T.Schneider, P.Selmer, Frank Wolter, Michael Zakharyaschev, http://ijcai.org/papers09/Abstracts/143.html We present a formal framework for (minimal) module extraction based on an abstract notion of inseparability w.r.t. a signature between ontologies. Two instances of this framework are discussed in detail for DL-Lite ontologies: concept inseparability, when ontologies imply the same complex concept inclusions over the signature, and query inseparability, when they give the same answers to existential queries for any instance data over the signature. We demonstrate that different types of corresponding minimal modules for these inseparability relations can be automatically extracted from large-scale DL-Lite ontologies by composing the tractable syntactic locality-based module extraction algorithm with intractable extraction algorithms using the multi-engine QBF solver AQME. The extracted minimal modules are compared with those obtained using non-logic-based approaches. text: http://ijcai.org/papers09/Papers/IJCAI09-143.pdf [Ответ][Цитата]
Capt.Drew Сообщений: 4179	На: Ai Drew :: IJCAI 09 :: Междунар. ии конфа: Позднее лето-2009 - Коротко о Главном Добавлено: 21 авг 09 7:05 PART-3: KNOWLEDGE REPRESENTATION, REASONING, and LOGIC: =144=> 0842p A Semantical Account of Progression in the Presence of Defaults, Gerhard Lakemeyer, Hector J. Levesque, http://ijcai.org/papers09/Abstracts/144.html In previous work, we proposed a modal fragment of the situation calculus called ES, which fully captures Reiter's basic action theories. ES also has epistemic features, including only-knowing, which refers to all that an agent knows in the sense of having a knowledge base. While our model of only-knowing has appealing properties in the static case, it appears to be problematic when actions come into play. First of all, its utility seems to be restricted to an agent's initial knowledge base. Second, while it has been shown that only-knowing correctly captures default inferences, this was only in the static case, and undesirable properties appear to arise in the presence of actions. In this paper, we remedy both of these shortcomings and propose a new dynamic semantics of only-knowing, which is closely related to Lin and Reiter's notion of progression when actions are performed and where defaults behave properly. text: http://ijcai.org/papers09/Papers/IJCAI09-144.pdf [Ответ][Цитата]
Capt.Drew Сообщений: 4179	На: Ai Drew :: IJCAI 09 :: Междунар. ии конфа: Позднее лето-2009 - Коротко о Главном Добавлено: 21 авг 09 7:05 PART-3: KNOWLEDGE REPRESENTATION, REASONING, and LOGIC: =145=> 0848p The Complexity of Learning Separable Ceteris Paribus Preferences, Jérôme Lang, Jérôme Mengin, http://ijcai.org/papers09/Abstracts/145.html We address the problem of learning preference relations on multi-attribute (or combinatorial) domains. We do so by making a very simple hypothesis about the dependence structure between attributes that the preference relation enjoys, namely separability (no preferential dependencies between attributes). Given a set of examples consisting of comparisons between alternatives, we want to output a separable CP-net, consisting of local preferences on each of the attributes, that fits the examples. We consider three forms of compatibility between a CP-net and a set of examples, and for each of them we give useful characterizations as well as complexity results. text: http://ijcai.org/papers09/Papers/IJCAI09-145.pdf [Ответ][Цитата]
Capt.Drew Сообщений: 4179	На: Ai Drew :: IJCAI 09 :: Междунар. ии конфа: Позднее лето-2009 - Коротко о Главном Добавлено: 21 авг 09 7:05 PART-3: KNOWLEDGE REPRESENTATION, REASONING, and LOGIC: =146=> 0854p Combining RCC-8 with Qualitative Direction Calculi: Algorithms and Complexity, Weiming Liu, Li Sanjiang, Renz Jochen, http://ijcai.org/papers09/Abstracts/146.html Increasing the expressiveness of qualitative spatial calculi is an essential step towards meeting the requirements of applications. This can be achieved by combining existing calculi in a way that we can express spatial information using relations from both calculi. The great challenge is to develop reasoning algorithms that are correct and complete when reasoning over the combined information. Previous work has mainly studied cases where the interaction between the combined calculi was small, or where one of the two calculi was very simple. In this paper we tackle the important combination of topological and directional information for extended spatial objects. We combine some of the best known calculi in qualitative spatial reasoning (QSR), the RCC8 algebra for representing topological information, and the Rectangle Algebra (RA) and the Cardinal Direction Calculus (CDC) for directional information. Although CDC is more expressive than RA, reasoning with CDC is of the same order as reasoning with RA. We show that reasoning with basic RCC8 and basic RA relations is in P, but reasoning with basic RCC8 and basic CDC relations is NP-Complete. text: http://ijcai.org/papers09/Papers/IJCAI09-146.pdf [Ответ][Цитата]
Capt.Drew Сообщений: 4179	На: Ai Drew :: IJCAI 09 :: Междунар. ии конфа: Позднее лето-2009 - Коротко о Главном Добавлено: 21 авг 09 7:05 PART-3: KNOWLEDGE REPRESENTATION, REASONING, and LOGIC: =147=> 0860p On First-Order Definability and Computability of Progression for Local-Effect Actions and Beyond, Yongmei Liu, Gerhard Lakemeyer, http://ijcai.org/papers09/Abstracts/147.html In a seminal paper, Lin and Reiter introduced the notion of progression for basic action theories in the situation calculus. Unfortunately, progression is not first-order definable in general. Recently, Vassos, Lakemeyer, and Levesque showed that in case actions have only local effects, progression is first-order representable. However, they could show computability of the first-order representation only for a restricted class. Also, their proofs were quite involved. In this paper, we present a result stronger than theirs that for local-effect actions, progression is always first-order definable and computable. We give a very simple proof for this via the concept of forgetting. We also show first-order definability and computability results for a class of knowledge bases and actions with non-local effects. Moreover, for a certain class of local-effect actions and knowledge bases for representing disjunctive information, we show that progression is not only first-order definable but also efficiently computable. text: http://ijcai.org/papers09/Papers/IJCAI09-147.pdf [Ответ][Цитата]
Capt.Drew Сообщений: 4179	На: Ai Drew :: IJCAI 09 :: Междунар. ии конфа: Позднее лето-2009 - Коротко о Главном Добавлено: 21 авг 09 7:06 PART-3: KNOWLEDGE REPRESENTATION, REASONING, and LOGIC: =148=> 0867p A Logic for Reasoning about Counterfactual Emotions, Emiliano Lorini, F.Schwarzentruber, http://ijcai.org/papers09/Abstracts/148.html The aim of this work is to propose a logical framework for the specification of cognitive emotions that are based on counterfactual reasoning about agents’ choices. An example of this kind of emotions is regret. In order to meet this objective, we exploit the well-known STIT logic [Belnap et al., 2001; Horty, 2001]. STIT logic has been proposed in the domain of formal philosophy in the nineties and, more recently, it has been imported into the field of theoretical computer science where its formal relationships with other logics for multiagent systems such as ATL and Coalition Logic (CL) have been studied. STIT is a very suitable formalism to reason about choices and capabilities of agents and groups of agents. Unfortunately, the version of STIT with agents and groups has been recently proved to be undecidable. In this work we study a decidable fragment of STIT with agents and groups which is sufficiently expressive for our purpose of formalizing counterfactual emotions. text: http://ijcai.org/papers09/Papers/IJCAI09-148.pdf [Ответ][Цитата]
Capt.Drew Сообщений: 4179	На: Ai Drew :: IJCAI 09 :: Междунар. ии конфа: Позднее лето-2009 - Коротко о Главном Добавлено: 21 авг 09 7:06 PART-3: KNOWLEDGE REPRESENTATION, REASONING, and LOGIC: =149=> 0873p Labellings and Games for Extended Argumentation Frameworks, Sanjay Modgil, http://ijcai.org/papers09/Abstracts/149.html Dung's abstract theory of argumentation has become established as a general framework for various species of non-monotonic reasoning, and reasoning in the presence of conflict. A Dung framework consists of arguments related by attacks, and the extensions of a framework, and so the status of arguments, are defined under different semantics. Developments of Dung's work have also defined argument labellings as an alternative way of characterising extensions, and dialectical argument game proof theories for establishing the status of individual arguments. Recently, Extended Argumentation Frameworks extend Dung's theory so that arguments not only attack arguments, but attacks themselves. In this way, the extended theory provides an abstract framework for principled integration of meta-level argumentation about defeasible preferences applied to resolve conflicts between object level arguments. In this paper we formalise labellings and argument games for a selection of Dung's semantics defined for the extended frameworks. text: http://ijcai.org/papers09/Papers/IJCAI09-149.pdf [Ответ][Цитата]
Capt.Drew Сообщений: 4179	На: Ai Drew :: IJCAI 09 :: Междунар. ии конфа: Позднее лето-2009 - Коротко о Главном Добавлено: 21 авг 09 7:06 PART-3: KNOWLEDGE REPRESENTATION, REASONING, and LOGIC: =150=> 0879p A Fixed-Parameter Tractable Algorithm for Spatio-Temporal Calendar Management, Bernhard Nebel, Jochen Renz, http://ijcai.org/papers09/Abstracts/150.html Calendar management tools assist users with coordinating their daily life. Different tasks have to be scheduled according to the user preferences. In many cases, tasks are at different locations and travel times have to be considered. Therefore, these kinds of calendar management problems can be regarded as spatio-temporal optimisation problems and are often variants of traveling salesman problems (TSP) or vehicle routing problems. While standard TSPs require a solution to include all tasks, prize-collecting TSPs are more suited for calendar management problems as they require a solution that optimises the total sum of prizes we assigned to tasks at different locations. If we now add time windows that limit when tasks can occur, these prize-collecting TSPs with time windows (TW-TSP) are excellent abstractions of spatio-temporal optimisation problems such as calendar management. Due to the inherent complexity of TW-TSPs, the existing literature considers mainly approximation algorithms or special cases. We present a novel algorithm for TW-TSPs that enables us to find the optimal solution to TW-TSP problems occurring in real-world calendar management applications efficiently. Our algorithm is a fixed-parameter tractable algorithm that depends on the maximal number of tasks that can be revisited from some other task, a parameter which is small in the application scenario we consider.text: http://ijcai.org/papers09/Papers/IJCAI09-150.pdf [Ответ][Цитата]
Capt.Drew Сообщений: 4179	На: Ai Drew :: IJCAI 09 :: Междунар. ии конфа: Позднее лето-2009 - Коротко о Главном Добавлено: 21 авг 09 7:06 PART-3: KNOWLEDGE REPRESENTATION, REASONING, and LOGIC: =151=> 0885p Reasoning with Knowledge, Action and Time in Dynamic and Uncertain Domains, Theodore Patkos, Dimitris Plexousakis, http://ijcai.org/papers09/Abstracts/151.html We propose a new framework for reasoning about knowledge, action and time for domains that include actions with non-deterministic and context-dependent effects. The axiomatization is based on the Event Calculus and combines the expressiveness of possible worlds semantics with the efficiency of approaches that dispense the use of the accessibility relation. The framework is proved logically sound and, when restricted to deterministic domains, is also logically complete. To prove correctness of the approach, we construct a knowledge theory based on a branching version of the Event Calculus and study their correlation. text: http://ijcai.org/papers09/Papers/IJCAI09-151.pdf [Ответ][Цитата]
Capt.Drew Сообщений: 4179	На: Ai Drew :: IJCAI 09 :: Междунар. ии конфа: Позднее лето-2009 - Коротко о Главном Добавлено: 21 авг 09 7:06 PART-3: KNOWLEDGE REPRESENTATION, REASONING, and LOGIC: =152=> 0891p Model-based Revision Operators for Terminologies in Description Logics, Guilin Qi, Jianfeng Du, http://ijcai.org/papers09/Abstracts/152.html The problem of revising an ontology consistently is closely related to the problem of belief revision which has been widely discussed in the literature. Some syntax-based belief revision operators have been adapted to revise ontologies in Description Logics (DLs). However, these operators remove the whole axioms to resolve logical contradictions and thus are not fine-grained. In this paper, we propose three model-based revision operators to revise terminologies in DLs. We show that one of them is more rational than others by comparing their logical properties. Therefore, we focus on this revision operator. We also consider the problem of computing the result of revision by our operator with the help of the notion of concept forgetting. Finally, we analyze the computational complexity of our revision operator. text: http://ijcai.org/papers09/Papers/IJCAI09-152.pdf [Ответ][Цитата]
Capt.Drew Сообщений: 4179	На: Ai Drew :: IJCAI 09 :: Междунар. ии конфа: Позднее лето-2009 - Коротко о Главном Добавлено: 21 авг 09 7:07 PART-3: KNOWLEDGE REPRESENTATION, REASONING, and LOGIC: =153=> 0898p Dialectical Abstract Argumentation: A Characterization of the Marking, Nicolas Rotstein, Martin Moguillansky, Guillermo Simari Criterion, http://ijcai.org/papers09/Abstracts/153.html This article falls within the field of abstract argumentation frameworks. In particular, we focus on the study of frameworks using a proof procedure based on dialectical trees. These trees rely on a marking procedure to determine the warrant status of their root argument. Thus, our objective is to formulate rationality postulates to characterize the marking criterion over dialectical trees. The behavior of the marking procedure is closely tied to the alteration of trees, which is the keystone of any model of change based on dialectical argumentation. Hence, the results achieved in this work will benefit research on dynamics in argumentation. text: http://ijcai.org/papers09/Papers/IJCAI09-153.pdf [Ответ][Цитата]
Capt.Drew Сообщений: 4179	На: Ai Drew :: IJCAI 09 :: Междунар. ии конфа: Позднее лето-2009 - Коротко о Главном Добавлено: 21 авг 09 7:07 PART-3: KNOWLEDGE REPRESENTATION, REASONING, and LOGIC: =154=> 0904p Composition of ConGolog Programs, Sebastian Sardina, Giuseppe De Giacomo, http://ijcai.org/papers09/Abstracts/154.html We look at composition of (possibly nonterminating) high-level programs over situation calculus action theories. Specifically the problem we look at is as follows: given a library of available ConGolog programs and a target program not in the library, verify whether the target program executions be realized by composing fragments of the executions of the available programs; and, if so, synthesize a controller that does the composition automatically. This kind of composition problems have been investigated in the CS and AI literature, but always assuming finite states settings. Here, instead, we investigate the issue in the context of infinite domains that may go through an infinite number of states as a result of actions. Obviously in this context the problem is undecidable. Nonetheless, by exploiting recent results in the AI literature, we devise a sound and well characterized technique to actually solve the problem. text: http://ijcai.org/papers09/Papers/IJCAI09-154.pdf [Ответ][Цитата]
Capt.Drew Сообщений: 4179	На: Ai Drew :: IJCAI 09 :: Междунар. ии конфа: Позднее лето-2009 - Коротко о Главном Добавлено: 21 авг 09 7:07 PART-3: KNOWLEDGE REPRESENTATION, REASONING, and LOGIC: =155=> 0911p Automated Theorem Proving for General Game Playing, Stephan Schiffel, Michael Thielscher, http://ijcai.org/papers09/Abstracts/155.html A general game player is a system that understands the rules of an unknown game and learns to play this game well without human intervention. To succeed in this endeavor, systems need to be able to extract and prove game-specific knowledge from the mere game rules. We present a practical approach to this challenge with the help of Answer Set Programming. The key idea is to reduce the automated theorem proving task to a simple proof of an induction step and its base case. We prove correctness of this method and report on experiments with an off-the-shelf Answer Set Programming system in combination with a successful general game player. text: http://ijcai.org/papers09/Papers/IJCAI09-155.pdf [Ответ][Цитата]
Capt.Drew Сообщений: 4179	На: Ai Drew :: IJCAI 09 :: Междунар. ии конфа: Позднее лето-2009 - Коротко о Главном Добавлено: 21 авг 09 7:07 PART-3: KNOWLEDGE REPRESENTATION, REASONING, and LOGIC: =156=> 0917p Nominals for Everyone, Lutz Schröder, Dirk Pattinson, Clemens Kupke, http://ijcai.org/papers09/Abstracts/156.html It has been recognised that the expressivity of description logics benefits from the introduction of non-standard modal operators beyond existential and number restrictions. Such operators support notions such as uncertainty, defaults, agency, obligation, or evidence, whose semantics often lies outside the realm of relational structures. Coalgebraic hybrid logic serves as a unified setting for logics that combine non-standard modal operators and nominals, which allow reasoning about individuals. In this framework, we prove a generic EXPTIME upper bound for concept satisfiability over general TBoxes, which instantiates to novel upper bounds for many individual logics including probabilistic logic with nominals. text: http://ijcai.org/papers09/Papers/IJCAI09-156.pdf [Ответ][Цитата]
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