Europe
A Theory of Meta-Diagnosis: Reasoning About Diagnostic Systems
Belard, Nuno (Airbus France, LAAS-CNRS, and Université) | Pencolé, Yannick (de Toulouse) | Combacau, Michel (LAAS-CNRS and Université)
In Model-Based Diagnosis, a diagnostic algorithm is typically used to compute diagnoses using a model of a real-world system and some observations. Contrary to classical hypothesis, in real-world applications it is sometimes the case that either the model, the observations or the diagnostic algorithm are abnormal with respect to some required properties; with possibly huge economical consequences. Determining which abnormalities exist constitutes a meta-diagnostic problem. We contribute, first, with a general theory of meta-diagnosis with clear semantics to handle this problem. Second, we propose a series of typically required properties and relate them between themselves. Finally, using our meta-diagnostic framework and the studied properties and relations, we model and solve some common meta-diagnostic problems.
Generalising the Interaction Rules in Probabilistic Logic
Hommersom, Arjen (Radboud University Nijmegen) | Lucas, Peter J. F. (Radboud University Nijmegen)
Probabilistic logics which is followed by the development of the main methods that support reasoning with probability distributions, used in generalising probabilistic Boolean interaction, and, such as ProbLog, use an implicit definition finally, default logic is briefly discussed. We will use probabilistic of an interaction rule to combine probabilistic evidence Boolean interaction as a sound and generic, algebraic about atoms. In this paper, we show that way to combine uncertain evidence, whereas default this interaction rule is an example of a more general logic will be used as our language to implement the interaction class of interactions that can be described by nonmonotonic operators, again reflecting this double perspective on the logics. We furthermore show that such probabilistic logic. The new probabilistic logical framework local interactions about the probability of an atom is described in Section 3 and compared to other approaches can be described by convolution. The resulting extended in Section 4. The achievements of this research are reflected probabilistic logic supports nonmonotonic upon in Section 5. reasoning with probabilistic information.
Minimum Search To Establish Worst-Case Guarantees in Coalition Structure Generation
Rahwan, Talal (University of Southampton) | Michalak, Tomasz P (University of Warsaw) | Jennings, Nicholas R (University of Southampton)
In this context, while it methods (see, e.g., [Shehory and Kraus, 1998; Sandholm et is desirable to generate a coalition structure that al., 1999; Sen and Dutta, 2000; Dang and Jennings, 2004; maximizes the sum of the values of the coalitions, Rahwan et al., 2009b]). In this context, an important line of the space of possible solutions is often too large research is the development of anytime CSG algorithms. In to allow exhaustive search. Thus, a fundamental particular, an algorithm is "anytime" if it can return a solution open question in this area is the following: Can we at any point of time during its execution, and the quality of its search through only a subset of coalition structures, solution improves monotonically until termination. This is and be guaranteed to find a solution that is within particularly desirable in the multi-agent system context since a desirable bound β from optimum? If so, what is the agents might not always have sufficient time to run the the minimum such subset?
Defeasible Inheritance-Based Description Logics
Straccia, Umberto (ISTI - CNR) | Casini, Giovanni (Scuola Normale Superiore)
Defeasible inheritance networks are a non-monotonic framework that deals with hierarchical knowledge. On the other hand, rational closure is acknowledged as a landmark of the preferential approach. We will combine these two approaches and define a new non-monotonic closure operation for propositional knowledge bases that combines the advantages of both. Then we redefine such a procedure for Description Logics, a family of logics well-suited to model structured information. In both cases we will provide a simple reasoning method that is build on top of the classical entailment relation.
LIMES — A Time-Efficient Approach for Large-Scale Link Discovery on the Web of Data
Ngomo, Axel-Cyrille Ngonga (University of Leipzig) | Auer, Sören (University of Leipzig)
The Linked Data paradigm has evolved into a powerful enabler for the transition from the document-oriented Web into the Semantic Web. While the amount of data published as Linked Data grows steadily and has surpassed 25 billion triples, less than 5\% of these triples are links between knowledge bases. Link discovery frameworks provide the functionality necessary to discover missing links between knowledge bases. Yet, this task requires a significant amount of time, especially when it is carried out on large data sets. This paper presents and evaluates LIMES, a novel time-efficient approach for link discovery in metric spaces. Our approach utilizes the mathematical characteristics of metric spaces during the mapping process to filter out a large number of those instance pairs that do not suffice the mapping conditions. We present the mathematical foundation and the core algorithms employed in LIMES. We evaluate our algorithms with synthetic data to elucidate their behavior on small and large data sets with different configurations and compare the runtime of LIMES with another state-of-the-art link discovery tool.
Computing Perfect Heuristics in Polynomial Time: On Bisimulation and Merge-and-Shrink Abstraction in Optimal Planning
Nissim, Raz (Ben-Gurion University) | Hoffmann, Joerg (INRIA) | Helmert, Malte (University of Freiburg)
A* with admissible heuristics is a very successful approach to optimal planning. But how to derive such heuristics automatically? Merge-and-shrink abstraction (M&S) is a general approach to heuristic design whose key advantage is its capability to make very fine-grained choices in defining abstractions. However, little is known about how to actually make these choices. We address this via the well-known notion of bisimulation. When aggregating only bisimilar states, M&S yields a perfect heuristic. Alas, bisimulations are exponentially large even in trivial domains. We show how to apply label reduction — not distinguishing between certain groups of operators — without incurring any information loss, while potentially reducing bisimulation size exponentially. In several benchmark domains, the resulting algorithm computes perfect heuristics in polynomial time. Empirically, we show that approximating variants of this algorithm improve the state of the art in M&S heuristics. In particular, a simple hybrid of two such variants is competitive with the leading heuristic LM-cut.
Trust Mechanisms for Online Systems
Witkowski, Jens (Albert-Ludwigs-Universität Freiburg)
The most prominent way to establish trust in online markets such as eBay are reputation systems that publish buyer feedback about a seller's past behavior. These systems, however, critically rely on assumptions that are rarely met in real-world marketplaces: first, it is assumed that there are no reporting costs and no benefits from lying so that buyers honestly report their private experiences. Second, it is assumed that every seller is long-lived, i.e. will continue to trade on the marketplace indefinitely and, third, it is assumed that sellers cannot whitewash, i.e. create new accounts once an old one is ran down. In my thesis, I address all of these assumptions and design incentive-compatible trust mechanisms that do not rely on any of the aforementioned assumptions. Moreover, I focus on designs that minimize common knowledge assumptions with respect to the players' valuations, costs and beliefs.
Efficient Rule-Based Inferencing for OWL EL
Krötzsch, Markus (University of Oxford)
We review recent results on inferencing for SROEL(×), a description logic that subsumes the main features of the W3C recommendation OWL EL. Rule-based deduction systems are developed for various reasoning tasks and logical sublanguages. Certain feature combinations lead to increased space upper bounds for materialisation, suggesting that efficient implementations are easier to obtain for suitable fragments of OWL EL.
From decision to action : intentionality, a guide for the specification of intelligent agents' behaviour
De Loor, Pierre, Pierre-Alexandre, Favier
This article introduces a reflexion about behavioural specification for interactive and participative agent-based simulation in virtual reality. Within this context, it is neces sary to reach a high level of expressivness in order to enforce interactions between the designer and the behavioural model during the in-line prototyping. This requires to consider the need of semantic very early in the design process. The Intentional agent model is here exposed as a possible answer. It relies on a mixed imperative and declarative approach which focuses on the link between decision and action. The design of a tool able to simulate virtual environment implying agents based on this model is discuss
A Temporal Neuro-Fuzzy Monitoring System to Manufacturing Systems
Mahdaoui, Rafik, Mouss, Leila Hayet, Mouss, Mohamed Djamel, Chouhal, Ouahiba
Fault diagnosis and failure prognosis are essential techniques in improving the safety of many manufacturing systems. Therefore, on-line fault detection and isolation is one of the most important tasks in safety-critical and intelligent control systems. Computational intelligence techniques are being investigated as extension of the traditional fault diagnosis methods. This paper discusses the Temporal Neuro-Fuzzy Systems (TNFS) fault diagnosis within an application study of a manufacturing system. The key issues of finding a suitable structure for detecting and isolating ten realistic actuator faults are described. Within this framework, data-processing interactive software of simulation baptized NEFDIAG (NEuro Fuzzy DIAGnosis) version 1.0 is developed. This software devoted primarily to creation, training and test of a classification Neuro-Fuzzy system of industrial process failures. NEFDIAG can be represented like a special type of fuzzy perceptron, with three layers used to classify patterns and failures. The system selected is the workshop of SCIMAT clinker, cement factory in Algeria.