Asif Akram

Evaluation of BPEL to Scientific Workflows

We investigate the requirements of Scientific Workflows in context of the Business Process Execution Language for Web Services (BPEL4WS/ BPEL. The complexity, unpredictability and inter-dependency of the components in a scientific workflow often demand flexibility in a workflowlanguage in order to support; 1) exception handling, 2) recovery from uncertain situations, 3) user interactions to facilitate interactive steering and monitoring, 4) dynamism to adapt to the changing environment, 5) compensation handling to roll back, and 6) support for dynamic selection of services. We illustrate these requirements with examples taken from a real scientific workflow; the e-HTPX project for high throughput protein crystallography. In this paper, we discuss the application of BPEL, which is widely regarded as the de-facto standard for orchestrating Web Services for Business Workflows with a large set of features to support complex requirements. These features, along with other standard tools, can be adapted to fulfill the requirements of Scientific Workflows.

Organization of grid resources in communities

Locating suitable resources within a Grid is a computationally intensive process, with no guarantee of quality and suitability of the discovered resources. An alternative approach is a middleware to categorize resources based on the services they provide - leading to the interaction of peers with common goals to form societies/communities. The middleware organizing resources in different communities is suggested to be useful for efficient resource discovery. The communities can be adaptive in nature and evolve based on changes in their operating environment -- such as changes in neighboring communities and user requirements. We have implemented JXTA prototype to illustrate the concepts of community formation in which Peers offering different services can be grouped together based on different criteria.

A workflow portal supporting multi-language interoperation and optimization

In this paper we present a workflow portal for Grid applications, which supports different workflow languages and workflow optimization. We present an XSLT converter that converts from one workflow language to another and enables the interoperation between different workflow languages. We discuss strategies for choosing the optimal service from several semantically equivalent Web services in a Grid application. The dynamic selection of Web services involves discovering a set of semantically equivalent services by filtering the available services based on metadata, and selecting an optimal service based on real‐time data and/or historical data recorded during prior executions. Finally, we describe the framework and implementation of the workflow portal which aggregates different components of the project using Java portlets. Copyright

Developing portals/portlets using Enterprise JavaBeans for Grid users

A Web‐based portal acting as a presentation layer to the Grid allows us to provide a transparent means of access to Grid resources. Our previous experiences in developing Grid portals have shown that there is a need to draw a clear high‐level picture of the architecture. This could be defined using the J2EE component‐oriented architecture, which enables a clear separation between the presentation, business logic and data layers. Additional benefits come with J2EE 1.4 making it possible to build up advanced service‐based Grid portals by exposing stateless session beans as Web services. In this paper, lessons learnt from our prototype portal/portlet development using Enterprise JavaBeans (EJB) are reported. Copyright

Comparison of JXTA and WSRF

Virtual collaboration among geographically dispersed resources, groups or organizational units requires support from their environment. The establishment, management and exploitation of dynamic, cross-organizational sharing relationship require new technology, which is independent of any proprietary technology and have backing of mainstream development and research institutes. This paper critically compares two peer-to-peer (P2P) protocols i.e. JXTA and Web services resource framework (WSRF) with respect to their effectiveness for virtual collaboration. The comparison is based on our experiences of developing a prototype for virtual organization. This paper is result of out going research to build community for efficient resource discovery.

CCLRC Portal infrastructure to support research facilities: Research Articles

Web portals are one of the possible ways to access the remote computing resources offered by Grid environments. Since the emergence of the first middleware for the Grid, works have been conducted on delivering the functionality of Grid services on the Web. Many interesting Grid portal solutions have been designed help organize remote access to Grid resources and applications from within Web browsers. They are technically advanced and more and more widely used around the world, resulting in feedback from the community. Some of these user comments concern the flexibility and user-friendliness of the developed solutions. In this paper we present how we addressed the need for a flexible and user-friendly Grid portal environment within the PROGRESS project and how our approach facilitates the use of the Grid within Web portals. Copyright

Organization of Virtual Communities

Locating suitable resources within a Grid system is a computationally intensive process, with no guarantee of quality and suitability of the discovered resources. An alternative approach is to categorize resources based on the services they provide -- leading to the interaction of peers with common goals to form societies/communities. Organization of resources in different communities is suggested to be useful for efficient resource discovery. We have implemented JXTA prototype to illustrate the concepts of community formation in which Peers offering different services can be grouped together based on different criteria.