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How agents accomplish a goal task in a multi-agent system is usually specified by multi-agent plans built from basic actions (e.g. operators) of which the agents are capable. The plan specification provides the agents with a shared mental model for how they are supposed to collaborate with each other to achieve the common goal. Making sure that the plans are reliable and fit for the purpose for which they are designed is a critical problem with this approach. To address this problem, this paper presents a formal approach to modeling and analyzing multi-agent behaviors using Predicate/Transition (PrT) nets, a high- level formalism of Petri nets. We model a multi-agent problem by representing agent capabilities as transitions in PrT nets. To analyze a multi-agent PrT model, we adapt the planning graphs as a compact structure for reachability analysis, which is coherent to the concurrent semantics. We also demonstrate that one can analyze whether parallel actions specified in multi-agent plans can be executed in parallel and whether the plans can achieve the goal by analyzing the dependency relations among the transitions in the PrT model.

In this paper, we apply π-calculus^1,2 to the planning for agents. First, we have proposed a new language for describing agent plans based on π-calculus, called PDL (Plan Description Language), and the model to execute them. The plans described in PDL can be changed dynamically while they are executing, because π-calculus provides dynamically-changing structures. By using this property, agents can change their plans to adapt to the environment around them by themselves in executing their plans. This property called reflection is very important to agents. We state the properties as theorems and prove them. Second, we have implemented an interpreter for PDL. In order to implement the system, we propose a primitive language, called PiL (Pi-calculus Language). PiL can be used on computers more easily than using the mathematical notations of π-calculus. We have shown that this system executes programs correctly and a plan written in PDL can be executed on the system. Finally, we have proved that the PDL is useful in the dynamically-changing environment by experiments.

Tuomela's philosophical account of joint intentions is formalized in a special setting in which fully specified plans are available for the execution of the intended joint action. Using additional modal logical assumptions the definition is simplified and used to investigate how the presence of a joint intention can be efficiently checked.

This paper explores the role of plans, as objects, in the formation of new innovation practice in organisations. A vocabulary for analysis is developed from innovation object theory. First, findings from an ethnographic study in a hospital organisation show that a plan serves several functions depending on its activation for use: a checklist of past practice (tertiary object), an opener for debates over current practice (secondary object) and a trigger for future practice development (primary object). Second, a framework is offered that shows how a plan supports different functionalities (evaluating, debating, further exploring) in a temporal dynamics of practice formation. Third, thus, plans play a significant role not only in planning activities, but also as connectors that shape and patch together pieces of past, present and future into what actually become new organisational practice. Finally, implications for innovation theory and management are drawn from these novel contributions.

This paper highlights perhaps one of the most fundamental issues constraining strategic environmental assessment (SEA) practice — its definition. Current reviews fail to explain why certain assessments are referred to as strategic while others are not. Furthermore, there appears to be very little attention given to the basic characteristics of strategy in the environmental assessment of proposed or existing policies, plans and programmes. This paper attempts to identify the characteristics of SEA that make it strategic and therefore different from other forms of impact assessment. A review of selected case studies is undertaken with the purpose of identifying those assessments that actually conform to the characteristics of a "strategic assessment". It is argued here that if SEA methodology and practice is to advance, then a common understanding of its definition and characteristics must first be achieved.

The Environmental Impact Assessment Law (EIA Law) of the People's Republic of China was adopted on 28 October 2002. It is the most progressive legislation addressing environmental issues in China to be developed over the past decade. The new EIA Law explicitly states that environmental impact assessment (EIA) is required for both new construction projects and plans. The types of plans covered by the new EIA Law include: (1) integrated plans for land use and regional development, development of drainage areas and marine areas; (2) specific plans for industry, agriculture, animal husbandry, forestry, energy, water management, transportation, urban construction, tourism and the development of natural resources. EIA for construction projects has been implemented in China for more than 20 years. Through this new EIA Law, the legal status of EIA for construction projects has been elevated from administrative legislation to State Law. EIA for plans is a type of strategic environmental assessment (SEA) where the concept of SEA is for the first time being advocated by the State at this level. This paper emphasises the legal requirements of SEA set forth by this new EIA Law, such as major purposes, key elements and procedures of EIA for plans.