Middleware for ubiquitous context-awareness

Ricardo Couto A. da Rocha, Markus Endler, Thiago Senador de Siqueira
2008 Proceedings of the 6th international workshop on Middleware for pervasive and ad-hoc computing - MPAC '08  
This position paper discusses the challenges and trade-offs of implementing a middleware that supports ubiquitous contextawareness, i.e., a scenario where context-aware applications may move throught network environments without suffering disruptions in their context-based interactions. We present a middleware approach based on the concept of context domains that satisfy some of the requirements of this scenario. they migrate between different environments, be they logical or physical
more » ... ts. Thus, currently environments enabling some form of context-awareness are isolated and independent, and do not support any application-transparent handover among each other. We call these isolated environments context-aware islands, because they hinder the implementation of applications with cross-environmental interest in context information, i.e., the context-aware interest of an application is a combination of contextual situations provided by context sources of different environments. Some middleware systems support such a scenario by offering distributed platforms for context management [12, 10, 8, 3] , federations of context-aware systems [7, 14, 2], or through bridges [11] between context-aware systems. However, we argue that such middlewares do not provide effective solutions, because their generality or scalability is limited. On one hand, more generic and flexible solutions usually only work properly with a small client base, since they impose high complexity on the context management mechanism. On the other hand, solutions that scale with the number of clients often support only lower-level abstractions for context usage for a specific application domain. We characterize this challenge as the development of a middleware that supports ubiquitous context-awareness. Ubiquitous context-awareness is thus the capability of a context-aware system or middleware to provide anytime access to heterogeneous, distributed, and un-anticipated context information in global scale and for distinct scenarios, allowing clients to discover new context types and information, restricted to a specific environment, and without compromising semantic context interoperability. In order to support this scenario, research in middleware must tackle issues such as: (context) generality, extensibility, computing and communication costs, portability, evolution support, and scalability [5] . There is a trade-off between these aspects and, unfortunately, there is not a single solution that adequately satisfies all these requirements. This paper discusses the challenges, requirements and tradeoffs of developing a middleware that provides ubiquitous context-awareness. We present an approach for context management that deals with some of these challenges and discuss some of our design decisions. UBIQUITOUS CONTEXT-AWARENESS Ubiquitous context-awareness is the ability to dynamically discover context-aware computational environments associated with the physical environment, and to keep both the access to context sources and the feasibility of the corre-
doi:10.1145/1462789.1462797 dblp:conf/middleware/RochaES08 fatcat:erifnqifivhg7ct5rm4jmt6ixa