— The microstructure identification problem is treated : given certain phases in given volume fractions, how to mix them in aperiodic cell so that the effective material constants of the periodic composite lie the closest possible to certain prescribed values ? The problem is studied for the linear conduction équation. It is stated in terms of optimal con trol theory ; the admissible micro geom...

Given a set of nodes N (i 1, 2, ..., n) which may represent cities and a set of requirements ria which may represent the number of telephone calls between N and N j, the problem is to build a spanning tree connecting these n nodes such that the total cost of communication of the spanning tree is a minimum among all spanning trees. The cost of communication for a pair of nodes is r;a multiplied ...

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This paper presents an approach to the wordlength allocation and optimization problem for linear digital signal processing systems implemented in Field-Programmable Gate Arrays. The proposed technique guarantees an optimum set of wordlengths for each internal variable, allowing the user to trade-off implementation area for error at system outputs. Optimality is guaranteed through modelling as a...

In [2], Duhamel obtained the optimal endfire array excitation by extending the Riblet’s broadside array design method. So, similar to the Riblet’s distribution, the obtained endfire distribution is limited to odd numbered arrays. In this section, authors present a broadened formulation which can be used for both even as well as odd numbered arrays. The basic idea behind this formulation comes f...

In this manuscript, we discuss the problem of determining the optimum stratification of a study (or main) variable based on the auxiliary variable that follows a uniform distribution. If the stratification of survey variable is made using the auxiliary variable it may lead to substantial gains in precision of the estimates. This problem is formulated as a Nonlinear Programming Problem (NLPP), w...

the chemical surfactant flooding can mobilize the trapped oil by lowering the interfacial tension between oil and brine and in some cases altering the reservoir rock wettability. in this work, the effect of surfactants on oil/brine interfacial tension was experimentally investigated. first, the effect of surfactants concentration was surveyed. afterwards, the effect of salinity on surfactant be...