We consider the problem of planning in complex domains where actions are stochastic, non-instantaneous, may occur concurrently, and time is represented explicitly. Our approach is based on the situation calculus based language Golog. Instead of general search for a sequence of actions, as in classical planning, we consider the problem of computing a deterministic, sequential program (with stoch...

Are the sources of ethnocentrism rather more sociological than psychological in nature? In order to answer this question, we review a classic debate between sociologists and psychologists. From this debate we distil two implicit theoretical models which are transposed into explicit and competitive models. A number of lacunas are filled with recent theoretical contributions and, subsequently, th...

I present a language for specifying planning problems in which there are external events, that is, events beyond the direct control of the planner which may happen while a plan is being executed. The language is based on Miller and Shanahan’s representation of narratives in the situation calculus. I describe an implemented planner that produces correct plans for this language, and discuss how s...

Projection in the situation calculus refers to answering queries about the future evolutions of the modeled domain, while progression refers to updating the logical representation of the initial state so that it reflects the changes due to an executed action. In the general case projection is not decidable and progression may require second-order logic. In this paper we focus on a recent result...

Traditional theories of delinquency causation generally fail to consider delinquency in the context of norms and age-role transitions peculiar to adolescence. Hence, in this study, an age-based theory of delinquency causation is developed, which assumes the importance of norms and roles specific to adolescence. This theory draws upon the assumption that socialization is recurrent, in contrast t...

BACKGROUND Previous studies have shown that in semi-spontaneous speech, individuals with Broca's and anomic aphasia produce relatively many direct speech constructions. It has been claimed that in 'healthy' communication direct speech constructions contribute to the liveliness, and indirectly to the comprehensibility, of speech. AIMS To examine the effects of the occurrence of direct speech c...

To compensate for the common inability of people with lexical production impairments to access and express intended concepts, we make use of models of human semantic memory that build on the notion of semantic similarity and relatedness. Such models, constructed on evidence gained from psycholinguistic experiments, form the basis of a large lexical database, WORDNET. We augment WORDNET with man...

This paper describes the case of an anomic patient (FH) who is impaired at naming pictures of objects but has no difficulties in recalling the names of familiar people. Even though his performance on McKenna's (1997) Category Specific Naming Test was at the first percentile, he consistently recalled the names of familiar people as successfully as controls. It is argued that the pattern of perfo...