When voice traffic is transported over a packet-based network, a number of conditions different from the ones in the traditional circuit-switched network will have an influence on the quality of the speech signal as perceived by the users. In particular, distortion of the voice signal due to delay jitter and partial loss of signal caused by packet loss will have an important impact. Therefore, in order to determine the influence of delay jitter and packet loss on the perceived quality, an objective speech quality assessment system, called DSLA, is used to predict the Mean Opinion Score for voice connections, which are set up on a test-bed, subject to artificially introduced network conditions. A decomposition of the voice degradation is made into different parts, due to sampling, digitization, encoding/decoding, packet loss and delay jitter, respectively. It Is found that delay jitter has a devastating influence on the perceived quality, when no dejittering buffer is used. However, when the received signal is dejittered, the degradation due to jitter is similar to the one caused by packet loss

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In this paper; we address the design of a generic and scalable platform f o r cluster computing. The architecture of the platforni is based on middleware technology in order to ensure easy distribution of the software components along the participating workstations and to exploit advanced comniunication techniques, such as event notifkation and object registration. The computational tasks are referred to as Intelligent Agents, which ure software agents that are capable of executing particular algorithms on input data. The developed platform offers advanced features such as transpurent load balancing, task scheduling, run time compilation of agent code and niigration of tasks. The architecture of the platjorni will be outlined from a computational point of view arid each component will be described in detail. Furthernrore, the engineering aspects of the platforni will be covered. In addition, a sample scenario f o r coniputational tasks in the area @ teleconimunication network design and niunagenient will be described.

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