Search

A mathematical model is presented that provides a well-defined formulation of the logical configuration problem of ATM networks (the carriers of future B-ISDN) with the objective of maximizing the total expected network revenue, given the physical network parameters and the traffic requirements of each virtual subnetwork. A two-phase solution procedure is developed in which the decision variables are the logical link capacities that specify the logical decomposition into virtual subnetworks, and the load sharing parameters. The first phase of the solution finds a global optimum in a rougher model. The second phase uses this as an initial point for a gradient-based hill climbing that applies the partial derivatives of the network revenue function obtained in a more refined model. >

Scatternet formation is one of the most important issues of emerging Wireless Personal Area Networks (WPANs). Numerous papers pointed out that the performance of a WPAN highly depends on the scatternet structure; however, for next generation WPANs (IEEE 802.15.3 and 802.15.4) the issue of scatternet formation is not discussed in the literature so far. This paper presents the techniques, constraints and effects of scatternet formation. First, the theoretically based problem is formulated in Integer Linear Programming (ILP) framework. Two heuristic methods are proposed for high-rate WPANs (802.15.3), which can be extended for low-rate WPANs (802.15.4) as well. The constructed networks are analyzed based on two metrics: (1) total network load, (2) amount of piconets. We show that network performance highly depends on the used algorithm: the network load can be reduced by up to 30% by using a proper scatternet formation algorithm. Furthermore, the scatternet can be optimized depending on the actual network traffic and individual objectives..

The efficient allocation of bandwidth in a cellular network with integrated heterogeneous ATM traffic poses a challenging problem, as the exact traffic mix or other detailed traffic descriptions are typically unknown in these networks. We present a an efficient solution that uses traffic parameters consisting only of the aggregated average traffic load in each cell and the available total bandwidth for each cluster of cells. We demonstrate that the proposed "Fair Share" algorithm can do significantly better than the intuitive load proportional bandwidth allocation. Furthermore, while for practicality the proposed method uses only aggregated traffic information, the solution provides a performance guarantee for even the most congested cells. The solution, built on nontrivial mathematical results, is simple, robust and well suited for practical implementation.

For pitch detection, voiced/unvoiced decisions and speech/nonspeech decisions, an improved average magnitude difference function (AMDF) is described that has given promising results: adaptation improves accuracy and skeletonization speeds up computation. A novel definition of time-warped distance results in decreased error probability in speech recognition; however, no fast algorithm for its computation has yet been found. The concept of time-warped average, on the other hand, is easy to compute and results in better speech recognition score. Both improved AMDF and time-warped distance are discussed for use in the speaker identification environment. >

The close similarity of the voices of consanguineous persons has suggested that there must exist hereditary phonetic parameters. To test this hypothesis, a method for characterizing numerically the similarity or dissimilarity of voices of twins with zygosity previously established by anthropological methods was elaborated. By speech processing and appropriate classification strategy the method has attained the discriminating power of blood-group determination for zygosity. The hereditability of certain physical parameters of the human voice has also been suggested.