This paper explores the truism that people think about what they say. It proposes that, to satisfy their own goals, people often plan their speech acts to affect their listeners' beliefs, goals, and emotional states. Such language use can be modelled by viewing speech acts as operators in a planning system, thus allowing both physical and speech acts to be integrated into plans. Methodological issues of how speech acts should be defined in a planbased theory are illustrated by defining operators (...) for requesting and informing. Plans containing those operators are presented and comparisons are drawn with Searle's formulation. The operators are shown to be inadequate since they cannot be composed to form questions (requests to inform) and multiparty requests (requests to request). By refining the operator definitions and by identifying some of the side effects of requesting, compositional adequacy is achieved.The solution leads to a metatheoretical principle for modelling speech acts as planning operators. (shrink)

Much previous work in artificial intelligence has neglected representing time in all its complexity. In particular, it has neglected continuous change and the indeterminacy of the future. To rectify this, I have developed a first‐order temporal logic, in which it is possible to name and prove things about facts, events, plans, and world histories. In particular, the logic provides analyses of causality, continuous change in quantities, the persistence of facts (the frame problem), and the relationship between tasks and actions. It (...) may be possible to implement a temporal‐inference machine based on this logic, which keeps track of several “maps” of a time line, one per possible history. (shrink)

In this paper we present a framework for describing cooperative work in informal domains such as an office. We argue that standard models of such work are inadequate for describing the adaptibility and variability observed in offices, and are fundamentally misleading as metaphors for understanding the skills and knowledge needed by computers or people to do the work. The basic claim in our alternative framework is that an agent's work is defined in terms of making and fulfilling commitments to other (...) agents, and that the tasks described in those commitments are merely agreed upon methods for fulfilling the commitments. Determining the intended meaning of those task descriptions in specific situations is an important component of the work, and the agents making the commitments decide in any given situation how and whether a given commitment has been fulfilled. We analyze subcontracting relationships, noting that the task's client and contractor both play a role in defining the subcontractor's work. Also, we analyze the use and role of procedures in informal domains, noting the interdependencies among the agents performing them, the problem solving required to perform each step, and ways in which they can be made more adaptive. Our analysis indicates that “intelligent” capabilities such as planning, plan monitoring, and negotiation are required to do even simple cooperative work. (shrink)