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TAYLOR-IDE, DANIEL and CARLE. TAYLOR (eds.). Just and Lasting Change: When Communities Own Their Futures. Baltimore, MD: The John Hopkins University Press, 2002, 350 pp.). Just and Lasting Change provides [...]

A simple method for the design of the finite-impulse-response prototype filter for maximally decimated overlapped complex-modulated transmultiplexers with near perfect reconstruction property is presented. The procedure is unified for all values of overlap factor and leads to a prototype filter with excellent frequency selectivity and fast sidelobe fall-off rate. The high stopband attenuation and fast sidelobe fall-off rate, which is justified analytically, make the proposed filters suitable candidates for high-speed data communication applications employing multicarrier modulation. Index Terms--Complex modulation, filter banks, multicarrier systems, multirate, near-perfect reconstruction, overlapped filter banks, pseudo-quadrature mirror filter (QMF), transmultiplexes.

Academic analysis of racial violence can often run the risk of generalising, therefore overlooking the specific context in which racial tensions can emerge. Against this background, it is useful to look at the extreme racial violence which took place in the East End of London, England, in late 1993 and 1994, giving particular attention to the realities of street life. It is vital that researchers understand the factors which create and define social problems .

An improved algorithm for discovering repfigit numbers yields the numbers 24769286411 and 96189170155. A computer search shows that no 10-digit repfigit exists. The limit of repfigit numbers and the multiple repfigits are discussed. A repfigit is a replicating Fibonacci digit, or an n-termed integer which appears in a Fibonacci-like sequence comprised of the first n terms of that integer.

A second-order adaptive filter structure is proposed here that can be used for frequency estimation and enhancement of an input sinusoid. Unlike other gradient based adaptive line enhancement schemes, this filter has the advantage that it can be made to converge arbitrarily fast by increasing the step size of the update, while still retaining stability. This becomes possible because the adaptation strategy has its roots in hyperstability theory. A limitation of the scheme is that it gives a biased estimate in the presence of noise; however, some techniques are described here that bring the bias down to a low level.

A generalized filter-bank structure is developed, to implement an arbitrary transform in a time-recursive manner. It is based on the NxN basis matrix of the transform, and for the general case, has a complexity of O(N squared); however, its complexity reduces considerably, to approximately 4N-5N, for the case of trigonometric transforms such as the DFT, DCT, and DST. As far as hardware complexity is concerned, it is similar to frequency sampling structures, but unlike them, it has much better behavior under finite precision arithmetic; it remains stable under coefficient truncation, and also does not sustain limit cycles if magnitude truncation is applied. The linear complexity, modularity, and good finite precision behavior of the structure make it extremely suitable for implementation using VLSI circuits or digital signal processors.

The game 'Scouts in the Desert' can be generalized to n dimensions to become 'Scouts in Hyperspace.' A hyperplane of (n-1) dimensions divides the space in half, with an army of individual points on one side which must advance by checkers jumps into the other side. The goal is to find the smallest army which can move any k steps into the other side. Properties of the game include a main theorem that 3n-1 is the upper bound on movement and lower bounds on army sizes to move 3n-2 steps.