engleski

PIE: End-User Programmable Internet Environment

Technological advances are driving the conventional human-centered Internet towards the "Internet of Things" that links together humans and devices with unique identity in a new form of cyberspace. Users of this new virtual world need new means of interaction with the cyberspace and its personalization. We developed three-layer SOPM (Service-Oriented Programming Model) that enables personalization of cyberspace through development of end-user applications. SOPM consists of execution, design, and translation environments. Distributed application execution environment is based on the Coopetition-Based Distributed Architecture (CBDA). We designed CBDA as the three-tiered coordination architecture that consists of Application services, Coopetition services, and Distributed programs. Application services implement coarse-grained fragments of computational logic. Coopetition services enable platform independent coordination and communication of the Application services. We have developed a set of Coopetition services that consists of Semaphore, MailBox, and EventChannel. Distributed programs handle cooperation and competition between Application services. They use Coopetition services in order to bind individual activities performed by Application services into a distributed application and execute application workflow without central control authority. In comparison with other models based on central control authority, CBDA reduces the distributed application execution time up to an order of magnitude. End-user distributed application design environment is based on the Simple Service Composition Language (SSCL). We defined a new programming language for service composition based on CBDA. Since SSCL is primarily intended for end-users, its syntax is simple but expressive enough to enable process modeling through Web service composition. In contrast to majority of XML-based orchestration and choreography languages, the SSCL is a statement-based textual language with simple syntax rules. Each SSCL primitive abstracts multiple WS-BPEL instruction blocks. Thus, SSCL programs hide all complexity of XML data handling, partner link definitions and initialization, SOAP message initialization, and other WS-BPEL programming constructs barely understandable to the end-user programmers. An SSCL program consists of a simple sequence of SSCL primitives. Three types of primitives are supported: service invocation, control-flow, and inter-service synchronization and communication. In comparison with other WS-BPEL based languages, SSCL language reduces the size of distributed application program up to three orders of magnitude and the distributed application design time up to two orders of magnitude. Distributed application translation environment is based on parallel distributed compilation and interpretation. In order to enable efficient execution of Distributed programs on CBDA, Distributed programs written in SSCL language are translated into CL (Coopetition Language). We defined CL language based on standard WS-BPEL and WSDL languages. Process description written in WS-BPEL language is ready for execution in any WS-BPEL compliant environment. We extended WS-BPEL language with WSDL descriptions of all invoked services in order to enable the distributed parallel interpretation of Distributed programs. Both translation processes, compilation of CL language from SSCL, and interpretation of CL language on the CBDA architecture, are executed as parallel distributed processes on arbitrary number of hosts. In comparison with other models based on centralized client-server architecture and service orchestration, our parallel distributed translation environment significantly reduces the distributed application translation time. We implemented the proposed SOPM model into end-user development framework PIE (Programmable Internet Environment). PIE is a web-browser based environment for building and running SOPM applications over the Internet. PIE provides facilities that enable installation and uninstallation of Application and Coopetition services, virtual network management, service composition, as well as translation and execution of Distributed programs. PIE is developed at School of Electrical Engineering and Computing, University of Zagreb, Croatia in cooperation with Ericsson Nikola Tesla d.d. The research is also sponsored by the Croatian Ministry of Science, Education, and Sports through national CroGrid project.

Consumer Computing

Google Mountain View, California, USA 06.01.2006.