Tuple Space Middleware for Wireless Networks

Abstract

Wireless networks define a very challenging scenario for the application programmer. Indeed, the fluidity inherent in the wireless media cannot be entirely masked at the communication layer: issues such as disconnection and a continuously changing execution context most often must be dealt with according to the application logic. Appropriate abstractions, usually provided as part of a middleware, are therefore required to support and simplify the programming task.Coordination [1] is a programming paradigm whose goal is to separate the definition of the individual behavior of application components from the mechanics of their interaction. This goal is usually achieved by using either message passing or data sharing as a model for interaction. Publish-subscribe, described in Chapter ?? is an example of the former, where coordination occurs only through the exchange of messages (events) among publishers and subscribers. While message passing, in its pure form, is inherently stateless, data sharing enables coordination among components by manipulating the (distributed) state of the system. The tuple space abstraction, the subject of this chapter, is a typical example of a data sharing approach. The two models, publish-subscribe and tuple spaces, have sometimes crossed paths in the scientific literature: their expressive power has been compared on formal grounds in [2]; the limits of an implementation of a stateful tuple space on top of a stateless publish-subscribe layer has been investigated in [3]; some extensions of publish-subscribe with stateful features exist (e.g., the ability to query over past events as in [4]). A thorough discussion of the relationship between the two is outside the scope of this chapter, and hereafter we focus solely on tuple spaces.Linda [5] is generally credited with bringing the tuple space abstraction to the attention of the programming community. In Linda, components communicate through a shared tuple space, a globally accessible, persistent, content-addressable data structure containing elementary data structures called tuples. Each tuple is a sequence of typed fields, as in "foo", 9, 27.5 , containing the information being communicated. A tuple t is inserted in a tuple space through an out(t) oper-1

Developing pervasive multi-agent systems with nature-inspired coordination

“…Indeed, middleware infrastructures for distributed network environments have been proposed that extend tuple-based model with the the specific aim of facilitating the expression of stigmergic features (for example through pheromone evaporation and diffusion) [52]. In the case of pervasive systems, stigmergic coordination has also been supported by exploiting pervasive devices such as sensor networks [56] or RFID tags [53,57].…”

A Novel Semantic IoT Middleware for Secure Data Management: Blockchain and AI-Driven Context Awareness

“…Database-oriented Centralises IoT data management [27][28][29] Structured data storage, support for complex queries Overheads, scalability issues, single points of failure Tuple spaces Distributed shared memory concept [30][31][32] Flexibility, synchronous/asynchronous communication…”

A Formal Approach to the Engineering of Domain-Specific Distributed Systems

“…Scel combines the idea of dynamically forming ensembles of agents -getting together to cooperatively work towards some collective goals -which has been extensively analysed [80,81] in the area of distributed artificial intelligence and multi-agent systems [82], with other concepts that have emerged from different research fields of Computer Science and Engineering. Indeed, it borrows from software engineering the importance of component-based design and separation of concerns [83], from multi-agent systems the relevance of knowledge handling and of spatial representation [84,85,86,87,88], from middleware and network architectures the importance of flexibility in communication [89,90,91,92,93], from distributed systems' security the role of policies [94], from actors and process algebras the importance of minimality and formality [95,96].…”