Li-Jie Jin

eFlow: a platform for developing and managing composite e-services

Today, companies are using the Web to connect with their back-end systems and perform e-commerce transactions. The next chapter of the Internet story is the evolution of todays access/content focused portals into e-services hubs. While many traditional services become available on the Internet as e-services, almost all of them are single point services. In order to offer higher value, end-to-end services, it should be possible to compose, customize, and deploy e-services in a very flexible and efficient way. To support e-service delivery, we have developed a platform, called eFlow, that provides the service developer with a simple, easy to use, yet powerful mechanism for defining the composite service starting from basic services. Composite services can be preassembled or created on the fly, and can dynamically adapt to changes in the business environment, such as the introduction of new basic services. In addition, eFlow includes components that allow users to monitor, analyze, and modify a service while in execution.

Adaptive and Dynamic Service Composition in eFlow

E-Services are typically delivered point-to-point. However, the e-service environment creates the opportunity for providing value-added, integrated services, which are delivered by composing existing e-services. In order to enable organizations to pursue this business opportunity we have developed eFlow, a system that supports the specification, enactment, and management of composite e-services, modeled as processes that are enacted by a service process engine. Composite e-services have to cope with a highly dynamic business environment in terms of services and service providers. In addition, the increased competition forces companies to provide customized services to better satisfy the needs of every individual customer. Ideally, service processes should be able to transparently adapt to changes in the environment and to the needs of different customers with minimal or no user intervention. In addition, it should be possible to dynamically modify service process definitions in a simple and effective way to manage cases where user intervention is indeed required. In this paper we show how eFlow achieves these goals.

Load balancing in distributed workflow management system

Management Systems (WFMS) play a very important role in constructing todays e-commerce environment through automating intra-enterprise business processes and inter-enterprise services. To handle the rapidly changing business environment and global competition, WFMSs should have flexibility and scalability to meet the business requirement and to quickly introduce new and efficient business services. Achieving load balancing is essential to ensure scalability in a distributed WFMS. In this paper we discuss load-balancing technology for distributed WFMSs. First, we introduce a workflow load index to measure load level of workflow engines. Then we present a WFMS cluster architecture with a load balancing subsystem. We compare the performance of round robin versus load- aware scheduling under the same load pattern. The experimental results show that the load index that we define in this paper is a good indicator of the load level in a distributed WMFS. The results also suggest that the load- aware scheduling algorithm can distribute workload fairly on heterogeneous WFMSs; instead, the round robin scheduling can only guarantee load balance in uniform WFMS with uniform workload and resource capabilities.