Showing papers by "Ralph Deters published in 2006"

Scheduling of composite web services

Abstract: Composite Web Services (CWS) aggregate multiple Web Services (WS) in one logical unit to accomplish a complex task (e.g business process) This aggregation is achieved by defining a workflow that orchestrates the underlying Web Services in a manner consistent with the desired functionality Since CWS can aggregate atomic WS and/or other CWS they foster the development of service layers and reuse of already existing functionality An important issue in the deployment of services is their run-time performance under various loads Due to the complex interactions of the underlying services, a CWS they can exhibit problematic and often difficult to predict behaviours in overload situations. This paper focuses on the use of request scheduling for improving CWS performance in overload situations Different scheduling policies are investigated in regards to their effectiveness in helping with bulk arrivals.

Seamless Communication and Access to Information for Mobile Users in a Wireless Environment

Abstract: Providing mobile workers with mobile devices such as a Compaq iPaq with a CDPD card can support them in retrieving information from centralized information systems. More specifically, mobile devices can enable mobile users to make notifications for schedule changes and add new data into the information system. In addition these devices can facilitate group communication anytime and anywhere. This paper presents different ways of providing non-critical information in a timely fashion for nomadic users of mobile devices using a wireless network. A distributed application prototype to support nomadic users is proposed, and a simulated environment is used to evaluate the prototype. Since solutions for seamless access are highly domain specific, the study involves homecare workers at Saskatoon District Health (SDH). By keeping track of the users’ current context (time, location etc.) and a user task model, it is possible to predict the information needs of mobile users and to provide context dependent adaptation of both the content and the functionality. Moreover, to avoid interrupts in the user’s interaction with the main information sources, methods for mobile transactions management using agent-based smart proxies that buffer, delay or pre-fetch information/data are introduced.