Abstract
Advances in the mobile device manufacture, rapid growth of Web services development and progression of wireless communication with the widespread use of Internet applications are the most recent trends in distributed information systems. The evolution of these trends yields the emergence of Mobile Web Services technology (MWS). Adaptive service provision and execution in mobile environments is a new avenue in MWS. It is emanated from the need to cope with the existence of mobile resource limitations to allow the reliable provision of a number of useful services that are hosted on these mobile devices. This research argues that the mechanisms used to facilitate service distribution allow non-interrupted provision of MWS efficiently. The objective of this research is to investigate these mechanisms and define a system for applying them. The main criteria for this system are flexibility, dynamicity and transparency. Simple Object Access Protocol (SOAP)-based Mobile Host Web service Framework (MHWF) is reproduced and extended as part of this research, to allow deploying, providing and executing SOAP-based services. Correspondingly, Representational State Transfer (RESTful) MHWF is defined and developed for providing RESTful-based services. Both frameworks have been analysed and compared in terms of performance, scalability, reliability and resource consumptions. Moreover, they both have been extended to allow service distribution through offloading, which is the first explored distribution mechanism. RESTful-based technology has shown that it is more convenient for mobile environment. This research also classifies the distribution strategies into three classes: Contentment Distribution (CD), Simple Partial Distribution (SPD) and Complex Partial Distribution (CPD). The distinction emerges from variance in the types and complexity levels of services that influence the quantity and quality of the distribution mechanisms’ usage. Novel approaches are proposed in order to exploit these mechanisms and to define and setup the building blocks for the corresponding MHWFs. The correct behaviour of these frameworks is empirically validated and their safety properties are also verified analytically using formal methods. This is complemented by a proof of concept demonstration. Furthermore, an evaluation of their performance is carried out by simulation. These evaluation results are interpreted as Fuzzy logic rules that are used to trigger and control distribution schemes. Last but not least, an innovative approach to partition and orchestrate the execution tasks of the distributed services is followed based on the hierarchical structure used for representing the Uniform Resource Identifier (URI) of the invoked services.