Mechanisms for environments in multi-agent systems: Survey and opportunities <s> Name: Resource and context manager. <s> The increasing need to access and elaborate dynamic and heterogeneous information sources distributed over Internet calls for new models and paradigms for application design and development. The mobile agent paradigm promotes the design of applications where agents roam through Internet sites to locally access ad elaborate information and resources, possibly cooperating with each other. This paper focuses on mobile agent coordination, and discusses the TuCSoN coordination model for Internet applications based on mobile information agents. The model is based on the notion of tuple centre, a tuple-based interaction space associated to each site and to be used both for inter-agent cooperation and for accessing to local infromation sources. TuCSoN tuple centres enhance tuple spaces because their behaviour in response to communication events can be programmed. This can be used to deal with heterogeneity and dynamicity of the information sources, as well as to ensure some degree of global data integrity. The effectiveness of the TuCSoN model is shown by means of an application example in the area of Internet information retrieval. <s> BIB001 </s> Mechanisms for environments in multi-agent systems: Survey and opportunities <s> Name: Resource and context manager. <s> Mobility introduces peculiar coordination problems in agent-based Internet applications. First, it suggests the exploitation of an infrastructure based on a multiplicity of local interaction spaces. Second, it may require coordination activities to be adapted both to the characteristics of the execution environment where they occur and to the needs of the application to which the coordinating agents belong. This paper introduces the concept of context-dependent coordination based on programmable interaction spaces. On the one hand, interaction spaces associated to different execution environments may be independently programmed so as to lead to differentiated, environment-dependent, behaviors. On the other hand, agents can program the interaction spaces of the visited execution environments to obtain an application-dependent behavior of the interaction spaces themselves. Several examples show how an infrastructure for context-dependent coordination can be exploited to simplify the design of Internet applications based on mobile agents. In addition, the MARS coordination infrastructure is presented as an example of a system in which the concept of context-dependent coordination has found a clean and efficient implementation. <s> BIB002 </s> Mechanisms for environments in multi-agent systems: Survey and opportunities <s> Name: Resource and context manager. <s> Coordinating the interactions of applications running on the diversity of both mobile and embedded devices that will be common in ubiquitous computing environments is still a difficult and not completely solved problem. We look at one such environment, an interactive workspace, where groups come together to collaborate on solving problems. Such a space will contain a heterogeneous collection of both new and legacy applications and devices. We propose the Event Heap, a coordination model most similar to tuplespaces, as being appropriate for such environments. We also present a prototype implementation of the Event Heap, and show that the system has performed well in actual use over the last two years in our prototype interactive workspace, the iRoom. <s> BIB003
Motivations: Need to represent context information and resources in an efficient way. Constituent atoms: Handling primitives and repositories. Creation and maintenance: Protocols to wrap new resources types (interfacing and deployment); algorithms to manage repositories. Usage: Agents access the repositories to interact efficiently. Examples: TuCSoN, Event Heap BIB002 BIB003 BIB001 These mechanisms are named as managers to emphasize their role in storing context information and interfacing with resources. Examples of this category of mechanisms are programmable tuple spaces, such as the MARS middleware BIB002 , TuCSoN BIB001 , and EventHeap BIB003 . A programmable tuple space is a middleware that offers two kinds of functionalities. On the one hand, it provides a shared data repository that can be accessed via pattern matching. It is possible to store in the tuple space any kind of contextual information (e.g. <temperature, 30 • C>), which can be retrieved later and shared among multiple agents (e.g. with the pattern <temperature, *>). On the other hand, the tuple space allows specific actions to execute when agents exploit it, e.g. to easily access data, to aggregate information, or to enforce security constraints. These functionalities rely on the programmable characteristics of the mechanism that consequently differs from standard tuple space  and blackboard architectures  . These mechanisms can serve both to communicate context-data about the environment and to exchange information among agents.