43,286 research outputs found

    How to be causal: time, spacetime, and spectra

    Full text link
    I explain a simple definition of causality in widespread use, and indicate how it links to the Kramers Kronig relations. The specification of causality in terms of temporal differential eqations then shows us the way to write down dynamical models so that their causal nature /in the sense used here/ should be obvious to all. To extend existing treatments of causality that work only in the frequency domain, I derive a reformulation of the long-standing Kramers Kronig relations applicable not only to just temporal causality, but also to spacetime "light-cone" causality based on signals carried by waves. I also apply this causal reasoning to Maxwell's equations, which is an instructive example since their casual properties are sometimes debated.Comment: v4 - add Appdx A, "discrete" picture (not in EJP); v5 - add Appdx B, cause classification/frames (not in EJP); v7 - unusual model case; v8 add reference

    Reformulation in planning

    Get PDF
    Reformulation of a problem is intended to make the problem more amenable to efficient solution. This is equally true in the special case of reformulating a planning problem. This paper considers various ways in which reformulation can be exploited in planning

    ā€œIn Other Words, ā€¦ā€: A Corpus-based Study of Reformulation in Judicial Discourse

    Get PDF
    The language of the law has been a favourite subject of investigation for both legal professionals and linguists for more than a decade now. Linguists, for instance, have paid increasing attention to the interplay of precise and ļ¬‚exible terms in legal drafting, and language variation across the genres of legal discourse. Among the latter, judgments have been discussed as a case in point by argumentation scholars, although the linguistic components of judicial argumentative discourse have often been overlooked. In the light of this, the aim of this paper is to carry out a corpus-based analysis of the open-ended category of reformulation markers as outstanding discursive items of judicial discourse in two comparable corpora of authentic judgments issued by two different courts of last resort, namely the Court of Justice of the European Communities and Irelandā€™s Supreme Court. By combining a qualitative with a quantitative analysis, the study shows that reformulation markers tend to activate a variety of discursive conļ¬gurations across the two courts. Hence, data reveal that reformulation strengthens the quality of both judicial narrative, as it were ā€“ as is clear from its deployment in clarifying the normative background and specifying the factual framework of disputes ā€“ and at once judicial argument, when judges characterise, reļ¬ne or grade reported arguments/interpretations or they wish to make their reasoning more solid and convincing

    A framework for investigating the interaction in information retrieval

    Get PDF
    To increase retrieval effectiveness, information retrieval systems must offer better supports to users in their information seeking activities. To achieve this, one major concern is to obtain a better understanding of the nature of the interaction between a user and an information retrieval system. For this, we need a means to analyse the interaction in information retrieval, so as to compare the interaction processes within and across information retrieval systems. We present a framework for investigating the interaction between users and information retrieval systems. The framework is based on channel theory, a theory of information and its flow, which provides an explicit ontology that can be used to represent any aspect of the interaction process. The developed framework allows for the investigation of the interaction in information retrieval at the desired level of abstraction. We use the framework to investigate the interaction in relevance feedback and standard web search

    Reasoning about Explanations for Negative Query Answers in DL-Lite

    Full text link
    In order to meet usability requirements, most logic-based applications provide explanation facilities for reasoning services. This holds also for Description Logics, where research has focused on the explanation of both TBox reasoning and, more recently, query answering. Besides explaining the presence of a tuple in a query answer, it is important to explain also why a given tuple is missing. We address the latter problem for instance and conjunctive query answering over DL-Lite ontologies by adopting abductive reasoning; that is, we look for additions to the ABox that force a given tuple to be in the result. As reasoning tasks we consider existence and recognition of an explanation, and relevance and necessity of a given assertion for an explanation. We characterize the computational complexity of these problems for arbitrary, subset minimal, and cardinality minimal explanations

    Analysing how constraints impact architectural decision-making

    Get PDF
    Architectural design projects are characterised by a high number of constraints. Along with planning, energy performance and fire safety regulations, current designers have to face constraining factors related to budget, acoustics, orientation, wind turbulence, accessibility for the disabled, and so forth. These constraints steer the design process implicitly and explicitly in certain directions as soon as architectural designers aim at satisfying design briefs. We aim in this article at analysing the impact of such constraints on the design process. At this end, we have studied four design sessions in a particular (student) design use case. In analysing these four sessions, we used linkography as a method, because this appeared to be one of the better options to obtain a more quantitative assessment of the design process. The linkography method was combined with an interview of the student design team, in order to check the correctness of our conclusions
    • ā€¦
    corecore