Africa
Learning Inadmissible Heuristics During Search
Thayer, Jordan Tyler (University of New Hampshire) | Dionne, Austin (University of New Hampshire) | Ruml, Wheeler (University of New Hampshire)
Suboptimal search algorithms offer shorter solving times by sacrificing guaranteed solution optimality. While optimal searchalgorithms like A* and IDA* require admissible heuristics, suboptimalsearch algorithms need not constrain their guidance in this way. Previous work has explored using off-line training to transform admissible heuristics into more effective inadmissible ones. In this paper we demonstrate that this transformation can be performed on-line, during search. In addition to not requiring training instances and extensive pre-computation, an on-line approach allows the learned heuristic to be tailored to a specific problem instance. We evaluate our techniques in four different benchmark domains using both greedy best-first search and bounded suboptimal search. We find that heuristics learned on-line result in both faster search andbetter solutions while relying only on information readily available in any best-first search.
Heuristics for Planning with SAT and Expressive Action Definitions
Rintanen, Jussi (The Australian National University)
We present the first effective SAT heuristics for planning with expressive planning languages such as ADL. Recently, SAT heuristics for STRIPS planning have been introduced. In this work we show that the basic ideas in the heuristic can be generalized to actions with conditional effects but without disjunction, and that disjunction requires a more fundamental analysis of the STRIPS heuristic, which, despite complications, will still lead to a natural heuristic which can be implemented efficiently. The experimental analysis shows substantial and systematic improvements over the state of the art in planning with SAT with ADL.
Modeling Interventions Using Belief Causal Networks
Boukhris, Imen (LARODEC - Universite de Tunis) | Elouedi, Zied (LARODEC - Universite de Tunis) | Benferhat, Salem (CRIL - Universite d'Artois)
Causality plays an important role in our comprehension of the world. It amounts to determine what truly causes what and what it matters. Interventions allow the identification of elements in a sequence of events that are related in a causal way. In this paper, we introduce belief causation and we proposea method for handling interventions in graphical model under an uncertain environment where the uncertainty is represented by belief masses, so-called belief causal networks. More specifically, we propose a generalization of the “DO” operator and explain the needed changes on the structure of the graph to model a belief causal network on which interventions are proceeded.
Statistical Machine Translation with Factored Translation Model: MWEs, Separation of Affixes, and Others
Okita, Tsuyoshi (Dublin City University) | Ceausu, Alexandru (Dublin City University) | Way, Andy (Dublin City University)
Expressions (MWEs) (Okita et al. 2010), this may improve the overall translation. For example in EN-JP, the empirical evidences 2007; Koehn 2010) intends to handle morphologically rich suggest that we separate affix(es) and word stem(s) since it languages in the target side by integrating additional linguistic obtains better BLEU score than the case when we do not separate markup at the word level, where each type of additional them although the adequacy decreases.
Opinion Extraction and Classification Based on Semantic Similarities
Elkhlifi, Aymen (Paris-Sorbonne University) | Bouchlaghem, Rihab (LARODEC, ISG de Tunis) | Faiz, Rim
This paper presents an automatic extraction and classification approach of opinions in texts. Therefore, we propose a similarity measurement calculating semantically similarities between a word and predefined subgroups of seed words. We have evaluated our approach on the semantic evaluation company “SemEval 2007” corpus, and we obtained promising results: the best value of Precision, 62%; and F1, 61%; as an improvement of 20 % compared to the participant systems.
Event Extraction Approach for French Language
Sellmi, Oussama (SOIE, ISG de Tunis)
S. Tenier, A. Napoli, X. Polanco and Y.Toussaint (2006) With the proliferation of news articles from thousands of developed an automatic WebPages semantic annotation different sources now available on the Web, summarization system. The objective is to classify pages concerning teams of such information is becoming increasingly important. of research, in order to be able to determine for example Considering the large number of news source (for who works where, on what and with whom (use of examples, BBC, Reuters, CNN…), every day, thousands of ontology of the domain). It consists, first, of the articles are produced in the entire world concerning a given identification of the syntactic structure characterizing the event.
Given Bilingual Terminology in Statistical Machine Translation: MWE-Sensitve Word Alignment and Hierarchical Pitman-Yor Process-Based Translation Model Smoothing
Okita, Tsuyoshi (Dublin City University) | Way, Andy (Dublin City University)
This paper considers a scenario when we are given almost perfect knowledge about bilingual terminology in terms of a test corpus in Statistical Machine Translation (SMT). When the given terminology is part of a training corpus, one natural strategy in SMT is to use the trained translation model ignoring the given terminology. Then, two questions arises here. 1) Can a word aligner capture the given terminology? This is since even if the terminology is in a training corpus, it is often the case that a resulted translation model may not include these terminology. 2) Are probabilities in a translation model correctly calculated? In order to answer these questions, we did experiment introducing a Multi-Word Expression-sensitive (MWE-sensitive) word aligner and a hierarchical Pitman-Yor process-based translation model smoothing. Using 200k JP--EN NTCIR corpus, our experimental results show that if we introduce an MWE-sensitive word aligner and a new translation model smoothing, the overall improvement was 1.35 BLEU point absolute and 6.0% relative compared to the case we do not introduce these two.
Combination of Topology and Nonmonotonic Logics for Typicality in a Scientific Field: Paleoanthropology
Jouis, Christophe (LIP6 (UPMC / CNRS)) | Jouis, Claude (Ecole Polytechnique) | Guy, Franck (Universite de Poitiers) | Habib, Bassel (LIP6 (UPMC / CNRS)) | Ganascia, Jean-Gabriel (LIP6 (UPMC / CNRS))
In computer science, ontology is a model of a domain in the form of classes and of relationships between these classes. Classes are organized in a graph the arrows of which are semantic relations. Ontology is static because the class hierarchy is fixed. In paleontology, systematic (i.e., the class hierarchies and the class relationships) is complicated by the time variable. Morphological changes over time yield, by natural selection, the emergence of new forms (taxa) differing from the ancestral morph and contemporaneous taxa of the same class hierarchy. Discovering new taxa implies, therefore, the rearrangement of the class hierarchy or the definition of new classes, based on the degree of atypicality of the new morph. Note that this phenomenon occurs in many domains such as physics, biology, linguistics, for example.
Combining Ontology Development Methodologies and Semantic Web Platforms for E-government Domain Ontology Development
Dombeu, Jean Vincent Fonou, Huisman, Magda
One of the key challenges in electronic government (e-government) is the development of systems that can be easily integrated and interoperated to provide seamless services delivery to citizens. In recent years, Semantic Web technologies based on ontology have emerged as promising solutions to the above engineering problems. However, current research practicing semantic development in e-government does not focus on the application of available methodologies and platforms for developing government domain ontologies. Furthermore, only a few of these researches provide detailed guidelines for developing semantic ontology models from a government service domain. This research presents a case study combining an ontology building methodology and two state-of-the-art Semantic Web platforms namely Protege and Java Jena ontology API for semantic ontology development in e-government. Firstly, a framework adopted from the Uschold and King ontology building methodology is employed to build a domain ontology describing the semantic content of a government service domain. Thereafter, UML is used to semi-formally represent the domain ontology. Finally, Protege and Jena API are employed to create the Web Ontology Language (OWL) and Resource Description Framework (RDF) representations of the domain ontology respectively to enable its computer processing. The study aims at: (1) providing e-government developers, particularly those from the developing world with detailed guidelines for practicing semantic content development in their e-government projects and (2), strengthening the adoption of semantic technologies in e-government. The study would also be of interest to novice Semantic Web developers who might used it as a starting point for further investigations.