A mechanism for creating web service interface to scientific applications.

Science is becoming increasingly multi-disciplinary and complicated. To solve complex scientific problems, we often need to integrate software and customize workflows to suit a particular problem. To make progress on key scientific issues, extended scientific collaborations are growingly dependent on complex workflows for data analysis and simulation. Service Oriented Architecture has gained popularity in recent years within scientific research community. It has been broadly accepted as a means of structuring interactions among distributed software services. Service Oriented Architecture is a new paradigm for accessing, integrating and coordinating loosely coupled software systems in a standardized way. It aims to reduce the cost of building and maintaining complex software systems while increasing their re-usability. However, most of the large industrial and scientific applications available today were written well before the introduction of Grid computing and Service Oriented Architectures. Hence, they are neither service oriented nor Grid-aware. There is a growing need to integrate them into Grid-aware applications based on Service Oriented Architecture. How to integrate these legacy applications into the Grid with the least possible effort and the best performance has become a crucial point. The majority of the applications developed and used by scientific communities are command-line applications. They are written in FORTRAN, C, and a host of scripting languages. In addition to being fast and efficient, these applications represent state-of- the-art science; however, they are bound by many limitations which make it difficult to compose complex workflows from them and run them on a distributed set of resources. By converting these command-line legacy applications into Application Services, it becomes easy to compose complex workflows from them and run them on the distributed resources. There are some research programs aiming at integrating the legacy codes into Grid infrastructure. Some frameworks have been developed to compose and run scientific workflows on a Grid. A number of systems are available to allow scientists to Grid- enabling their existing applications without having to write extra code or modify their applications. But most of them do not provide a toolkit for wrapping an application as a Grid-aware Web service. Few of the systems have addressed the issue of security. This thesis presents an approach to reducing the required effort needed in developing Application Services for end users. Also during the execution of complex scientific workflows, Application Services often become unavailable primarily due to the unreliable nature of the resources that host them. When an Application Service becomes unavailable, all workflows that are accessing it have to stop, and this means wasting a great deal of time and resources. This thesis offers a new solution to this problem, via providing a mechanism by which Application Service can be created on-demand from workflows in case it is unavailable