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Top1. Introduction
Interoperability is the ability of a system to interact with other systems, possibly from different manufacturers, with the intent of sharing services and data among them. Middleware plays an important role in bridging the barrier between heterogeneous systems by providing a layer of abstraction to mask the heterogeneity of the underlying operating systems and hardware devices used. As long as there is one middleware standard operating, interoperability among the systems can be achieved. However, such common standards in the field of distributed systems are rare owing to the plethora of various middleware standards competing on the market. Recent distributed systems contribute to a wider variety of services such as sensor-based, mobile, ubiquitous and Internet-based. The level of heterogeneity, exhibited through the usage of hardware devices, operating systems, varying communication styles -infrastructure-based, ad-hoc and mobile- and new programming paradigms, significantly surpasses that of previous generation distributed systems. Given the high heterogeneity and dynamicity of evolving systems, the level of complexity in achieving interoperability has considerably increased. It is clear that such a problem necessitates more advanced and principled solutions that go beyond the state-of-the-art in middleware. This implies investigating new methodologies to explore the heterogeneity issue in distributed systems at run time. In particular, this paper looks into the potential use of ontologies to address heterogeneity in distributed systems, more specifically in VANETs. The aims of this work can be summed up as:
- 1.
To investigate the potential role of ontologies in an emergent middleware architecture to resolve the underlying heterogeneity arising at different levels in a system
- 2.
To investigate the potential role of ontologies in an emergent middleware architecture to enable a semantic reasoning at a conceptual level of a system
The work presented in this paper was carried out for a PhD thesis, and detailed information about this proposed framework can be found at (Nundloll, 2013).
Top2. Illustrating The Challenges
Interoperation is possible between two distributed systems if both are able to interact at their application, middleware and network levels. Applications differ in terms of their data formats and interface methods; middleware protocols differ in their behaviour and message formats, and network protocols differ in their communication styles and packet formats. The need to handle heterogeneity in a distributed system has been highlighted in (Bennaceur, 2015), where a unified approach is adopted to deal with the interoperability issue at the application and the middleware layers. The emergent middleware concept has been contributed by the distributed system community whereby different systems are able to establish a dynamic connection at run time. The purpose of such an emergent middleware is to provide a level of abstraction on the different middleware standards employed by these systems. (Blair, 2011; Grace, 2009; Nundloll, 2011) present the contributions of the Connect project in enabling interoperability through an emergent middleware.