No abstract

While the concept of UDDI supports the automatic discovery of services implementing a common public tModel interface, there have been only few attempts to find a standardized form to describe the quality of service (QoS) properties of Web services.We introduce our approach "Web service QoS (WSQoS)" that enables an efficient, dynamic, and QoS-aware selection and monitoring of Web services. The prototype of our approach is implemented with the .NET technology, including the following components: a WSQoS Editor for the specification of QoS properties, a WSQoS Requirement Manager for retrieving QoS requirements specified by client applications, a Web service broker for an efficient and QoS-aware selection of Web service offers, and a WS-QoS Monitor for checking the compliance of the service offers.

Eiiergy conservation plays a crucial in wireless sensor networks since such networks are designed to be placed in hostile and non-accessible areas. While battery-driven sensors will run out of battery sooner or late< the use of renewable energy sources such as solar power or gravitation may extend the lifetime of a sensor network. We propose to utilize solar power in wireless sensor networks and extend LEACH a well-known cluster-based protocol for sensor networks to become solar-aware. The presented simulation results show that making LEACH solar-aware significantly extends the lifetime of sensor networks.

Sensor networks are designed especially for deployment in adverse and non-accessible areas without a fixed infrastructure. Therefore, energy conservation plays a crucial role for these networks. We propose to utilize solar power in wireless sensor networks, establishing a topology where -changing over time -some nodes can receive and transmit packets without consuming the limited battery resources. We propose and evaluate two protocols that perform solaraware routing. The presented simulation results show that both protocols provide significant energy savings when utilizing solar power. The paper shows that incorporating the solar status of nodes in the routing decision is feasible and results in reduced overall battery consumption.

Wireless sensor networks are based on the collaborative efforts of many small wireless sensor nodes, which collectively are able to form networks through which sensor information can be gathered. Such networks usually cannot operate in complete isolation, but must be connected to an external network to which monitoring and controlling entities are connected. As TCP/IP, the Internet protocol suite, has become the de-facto standard for large-scale networking, it is interesting to be able to connect sensornets to TCP/IP networks. In this paper, we discuss three different ways to connect sensor networks with TCP/IP networks: proxy architectures, DTN overlays, and TCP/IP for sensor networks. We conclude that the methods are in some senses orthogonal and that combinations are possible, but that TCP/IP for sensor networks currently has a number of issues that require further research before TCP/IP can be a viable protocol family for sensor networking.