Nicholas Asher

Bio: Nicholas Asher is an academic researcher from Centre national de la recherche scientifique. The author has contributed to research in topics: Semantics & Discourse representation theory. The author has an hindex of 41, co-authored 211 publications receiving 8889 citations. Previous affiliations of Nicholas Asher include University of Stuttgart & Aix-Marseille University.

Logics of conversation

Abstract: Preface Acknowledgements 1 Motivations 2 Semantic models of discourse interpretation 3 Pragmatic models of discourse interpretation 4 The logical form of discourse 5 Building logical forms for discourse 6 The lexicon and discourse structure 7 Discourse relations for dialogue 8 Disputes in dialogue 9 Cognitive modelling 10 Some concluding remarks: A Objections and replies B Notation index C The semantics of DRT D Glossary of discourse relations E Summary of discourse update F Some proofs in the glue logic References Indexes

Indirect Speech Acts

Abstract: In this paper, we address several puzzles concerning speech acts,particularly indirect speech acts. We show how a formal semantictheory of discourse interpretation can be used to define speech actsand to avoid murky issues concerning the metaphysics of action. Weprovide a formally precise definition of indirect speech acts, includingthe subclass of so-called conventionalized indirect speech acts. Thisanalysis draws heavily on parallels between phenomena at the speechact level and the lexical level. First, we argue that, just as co-predicationshows that some words can behave linguistically as if they're `simultaneously'of incompatible semantic types, certain speech acts behave this way too.Secondly, as Horn and Bayer (1984) and others have suggested, both thelexicon and speech acts are subject to a principle of blocking or ``preemptionby synonymy'': Conventionalized indirect speech acts can block their`paraphrases' from being interpreted as indirect speech acts, even ifthis interpretation is calculable from Gricean-style principles. Weprovide a formal model of this blocking, and compare it withexisting accounts of lexical blocking.

Reference to Abstract Objects in Discourse

Abstract: Preface. Introduction. 1. From Events to Propositions: a Tour of Abstract Entities, Eventualities and the Nominals that Denote them. 2. A Crash Course in DRT. 3. Attitudes and Attitude Descriptions. 4. The Semantic Representation for Sentential Nominals. 5. Problems for the Semantics of Nominals. 6. Anaphora and Abstract Entities. 7. A Theory of Discourse Structure for an Analysis of Abstract Entity Anaphora. 8. Applying the Theory of Discourse Structure to the Anaphoric Phenomena. 9. Applications of the Theory of Discourse Structure to Concept Anaphora and VP Ellipsis. 10. Model Theory for Abstract Entities and its Philosophical Implications. Conclusion. Bibliography. Index.

Temporal interpretation, discourse relations and commonsense entailment

Abstract: This paper presents a formal account of how to determine the discourse relations between propositions introduced in a text, and the relations between the events they describe. The distinct natural interpretations of texts with similar syntax are explained in terms of defeasible rules. These characterise the effects of causal knowledge and knowledge of language use on interpretation. Patterns of defeasible entailment that are supported by the logic in which the theory is expressed are shown to underly temporal interpretation.

Lexical Meaning in Context: A Web of Words

Abstract: Preface Part I. Foundations: 1. Lexical meaning and predication 2. Types and lexical meaning 3. Previous theories of prediction Part II. Theory: 4. Type composition logic 5. The complex type 6. Type presuppositions in TCL Part III. Development: 7. Restricted predication 8. Rethinking coercion 9. Other coercions 10. Syntax and type transformations 11. Modification, coercion and loose talk 12. Generalizations and conclusions Part IV. Coda: References Index.

Intelligent Agents: Theory and Practice

Abstract: The concept of an agent has become important in both Artificial Intelligence (AI) and mainstream computer science. Our aim in this paper is to point the reader at what we perceive to be the most important theoretical and practical issues associated with the design and construction of intelligent agents. For convenience, we divide these issues into three areas (though as the reader will see, the divisions are at times somewhat arbitrary). Agent theory is concerned with the question of what an agent is, and the use of mathematical formalisms for representing and reasoning about the properties of agents. Agent architectures can be thought of as software engineering models of agents;researchers in this area are primarily concerned with the problem of designing software or hardware systems that will satisfy the properties specified by agent theorists. Finally, agent languages are software systems for programming and experimenting with agents; these languages may embody principles proposed by theorists. The paper is not intended to serve as a tutorial introduction to all the issues mentioned; we hope instead simply to identify the most important issues, and point to work that elaborates on them. The article includes a short review of current and potential applications of agent technology.

Sentiment Analysis and Opinion Mining

Abstract: Sentiment analysis and opinion mining is the field of study that analyzes people's opinions, sentiments, evaluations, attitudes, and emotions from written language. It is one of the most active research areas in natural language processing and is also widely studied in data mining, Web mining, and text mining. In fact, this research has spread outside of computer science to the management sciences and social sciences due to its importance to business and society as a whole. The growing importance of sentiment analysis coincides with the growth of social media such as reviews, forum discussions, blogs, micro-blogs, Twitter, and social networks. For the first time in human history, we now have a huge volume of opinionated data recorded in digital form for analysis. Sentiment analysis systems are being applied in almost every business and social domain because opinions are central to almost all human activities and are key influencers of our behaviors. Our beliefs and perceptions of reality, and the choices we make, are largely conditioned on how others see and evaluate the world. For this reason, when we need to make a decision we often seek out the opinions of others. This is true not only for individuals but also for organizations. This book is a comprehensive introductory and survey text. It covers all important topics and the latest developments in the field with over 400 references. It is suitable for students, researchers and practitioners who are interested in social media analysis in general and sentiment analysis in particular. Lecturers can readily use it in class for courses on natural language processing, social media analysis, text mining, and data mining. Lecture slides are also available online.

BDI Agents: From Theory to Practice

Abstract: The study of computational agents capable of rational behaviour has received a great deal of attention in recent years. Theoretical formalizations of such agents and their implementations have proceeded in parallel with little or no connection between them. Tkis paper explores a particular type of rational agent, a BeliefDesire-Intention (BDI) agent. The primary aim of this paper is to integrate (a) the theoretical foundations of BDI agents from both a quantitative decision-theoretic perspective and a symbolic reasoning perspective; (b) the implementations of BDI agents from an ideal theoretical perspective and a more practical perspective; and (c) the building of large-scale applications based on BDI agents. In particular, an air-trafflc management application will be described from both a theoretical and an implementation perspective.

Introduction to Multiagent Systems

Abstract: From the Publisher: An agent is an entity with domain knowledge, goals and actions. Multi-agent systems are a set of agents which interact in a common environment. Multi-agent systems deal with the construction of complex systems involving multiple agents and their coordination. A multi-agent system (MAS) is a distributed computing system with autonomous interacting intelligent agents that coordinate their actions so as to achieve its goal(s) jointly or competitively.

Lexicon-based methods for sentiment analysis

Abstract: We present a lexicon-based approach to extracting sentiment from text. The Semantic Orientation CALculator (SO-CAL) uses dictionaries of words annotated with their semantic orientation (polarity and strength), and incorporates intensification and negation. SO-CAL is applied to the polarity classification task, the process of assigning a positive or negative label to a text that captures the text's opinion towards its main subject matter. We show that SO-CAL's performance is consistent across domains and in completely unseen data. Additionally, we describe the process of dictionary creation, and our use of Mechanical Turk to check dictionaries for consistency and reliability.