Multi-mode resource availability cost problem with recruitment and release dates for resources

This paper investigates the multi-mode resource availability cost problem with recruitment and release dates for resources. This problem is a more realistic model and extended case of the resource availability cost problem. The project contains activities interrelated by finish–start precedence relations with zero time lags, which require a set of renewable resources. First, a mixed integer programming formulation is proposed for the problem. Then, simulated annealing (SA) algorithm is proposed to obtain a satisfying solution for this NP-hard problem. The effectiveness of the proposed algorithm is demonstrated through comprehensive experimentation based on 300 test problems. The results are analyzed and discussed.     

Forecasting the partisan composition of the house as a function of seniority

This note examines the influence of seniority of the partisan composition of the House of Representatives. A model is developed to compute the re-election probabilities as a function of the levels of seniority. These estimates, together with the composition of the immediately preceding congress, are then used to estimate the composition of any congress and the results compared to the actual electoral outcomes. The end result is a partisan composition or the House independent of the short-term fluctuations created by issues relevant to the individual elections. In addition, measures of accuracy of the estimates are computed in order to assertain how much of the variation in the data is left to be explained by issue-oriented factors.     

Numerical analysis of the weighted particle method applied to the semiconductor Boltzmann equation

Summary The semiconductor Boltzmann equation involves an integral operator, the kernel of which is a measure supported by a surface. This feature introduces some singularities of the exact solution, which makes the numerical approximation of this equation difficult. This paper is devoted to the error analysis of the weighted particle method (introduced by Mas-Gallic and Raviart [14]) applied to the space homogeneous semiconductor Boltzmann equation. The results are commented in view of the practical use of the method. This paper is closely related to [12], where results of numerical simulations on both test and real problems are given.     

The Durand-Kerner polynomials roots-finding method in case of multiple roots

The convergence of the Durand-Kerner algorithm is quadratic in case of simple roots but only linear in case of multiple roots. This paper shows that, at each step, the mean of the components converging to the same root approaches it with an error proportional to the square of the error at the previous step. Since it is also shown that it is possible to estimate the multiplicity order of the roots during the algorithm, a modification of the Durand-Kerner iteration is proposed to preserve a quadratic-like convergence even in case of multiple zeros.This work is supported in part by the Research Program C3 of the French CNRS and MEN, and by the Direction des Recherches et Etudes Techniques (DGA).     

On the numerical analysis of the Von Karman equations: Mixed finite element approximation and continuation techniques

Summary The purpose of this paper is to study the approximation of the Von Karman equations by the mixed finite element scheme of Miyoshi and to follow the solutions arcs at a neighbourhood of the first eigenvalue of the linearized problem. This last problem is solved by a continuation method.     

A variational principle for fractal dimensions

A new definition of the dimension of probability measures is introduced. It is related with the fractal dimension of sets by a variational principle. This principle is applied in the theory of iterated function systems.     

Optimal allocation of service rates in Jackson network of queues with total finite accommodating space

This paper deals with the solutions of problems of optimal allocation of service rates in Jackson network of queues with total finite accommodating space. The optimal service rates have been found by using geometric programming techniques.Numerical results have also been given in the text.     

A constraint linearization method for nondifferentiable convex minimization

Summary This paper presents a readily implementable algorithm for solving constrained minimization problems involving (possibly nonsmooth) convex functions. The constraints are handled as in the successive quadratic approximations methods for smooth problems. An exact penalty function is employed for stepsize selection. A scheme for automatic limitation of penalty growth is given. Global convergence of the algorithm is established, as well as finite termination for piecewise linear problems. Numerical experience is reported.Sponsored by Program CPBP 02.15     

Clones on three elements preserving a binary relation

We describe the clones on 3 elements that can be expressed as Pol ρ for ρ a binary relation. We present the poset of these clones ordered by inclusion. This article is a shortened version of the author’s thesis, to give an idea of the whole work. Presented by R. P?schel. Received March 24, 2005; accepted in final form December 20, 2005.     

On convolution equations with semi-almost periodic symbols on a finite interval

This note concerns a class of Wiener-Hopf operators on a finite interval, acting between Sobolev multi-index spaces. Necessary and sufficient conditions for such an operator to be Fredholm are given, as well as a formula for the index. The argument is based on a reduction procedure of convolution operators on a finite interval to operators of the same type on the half-line.supported by the Netherlands organization for scientific research (NWO)supported in part by NSF Grant 9101143     

Boundedness and Regularity Properties of Semismooth Reformulations of Variational Inequalities

The Karush-Kuhn-Tucker (KKT) system of the variational inequality problem over a set defined by inequality and equality constraints can be reformulated as a system of semismooth equations via an nonlinear complementarity problem (NCP) function. We give a sufficient condition for boundedness of the level sets of the norm function of this system of semismooth equations when the NCP function is metrically equivalent to the minimum function; and a sufficient and necessary condition when the NCP function is the minimum function. Nonsingularity properties identified by Facchinei, Fischer and Kanzow, 1998, SIAM J. Optim. 8, 850–869, for the semismooth reformulation of the variational inequality problem via the Fischer-Burmeister function, which is an irrational regular pseudo-smooth NCP function, hold for the reformulation based on other regular pseudo-smooth NCP functions. We propose a new regular pseudo-smooth NCP function, which is piecewise linear-rational and metrically equivalent to the minimum NCP function. When it is used to the generalized Newton method for solving the variational inequality problem, an auxiliary step can be added to each iteration to reduce the value of the merit function by adjusting the Lagrangian multipliers only. This work is supported by the Research Grant Council of Hong Kong This paper is dedicated to Alex Rubinov on the occasion of his 65th Birthday     

The indicatrix method. II

Summary This paper extends the earlier results by the author on two-dimensional free boundary problems. The main aim consists in derivation of an optimal error bound for the approximations of the free boundary.     

Remarks on parameter identification. I

Summary In this paper a method for constructing a spatially varying diffusion coefficient for a parabolic, partial differential equation is given. This function is obtained as the limit of a sequence of functions which are obtained by solving a sequence of finite dimensional optimization problems.Dedicated to Professor Lothar Collatz on the occasion of his 75th birthdaySupported in part by a grant from NORCUS with funds provided by the Department of Energy as part of the Basalt Waste Isolation Project     

Subplane covered affine planes

Projective or affine planes that are covered by subplanes in a prescribed manner are studied and classified. This provides a generalization of the concept of regular spread.This research begun while the second author was a C.N.R. visiting professor in Italy during May–June 1994.     

Approximation of multivariable functions with respect to random points less than 2 k,k dimension of space

Summary The problem of the numerical approximation of multivariable functions has been solved by the Monte Carlo method when the data points are assumed to be given on discrete lattice points [5, 8, 2]. When the data points are randomly distributed and very numerous there are some results in the literature [3, 6] but if the number of the points is less than 2 ^k , wherek is the dimension of the space, it is very difficult to develop approximation formulas. This paper gives a solution to this problem by local approximations.     

Defect correction from a Galerkin viewpoint

Summary We consider the numerical solution of systems of nonlinear two point boundary value problems by Galerkin's method. An initial solution is computed with piecewise linear approximating functions and this is then improved by using higher-order piecewise polynomials to compute defect corrections. This technique, including numerical integration, is justified by typical Galerkin arguments and properties of piecewise polynomials rather than the traditional asymptotic error expansions of finite difference methods.     

A convergence condition for the quadrilateral Wilson element

Summary The paper deals with the convergence properties of the nonconforming quadrilateral wilson element which violates the patch test. The convergence of the element is proved under a certain condition on mesh subdivisions without any modifications of the variational formulation. This result extends the range of applicability of Wilson's element. The necessity of the proposed condition is also discussed.This work was written while the author was visiting the University of Frankfurt, Federal Republic of Germany, on a grant by the Alexander von Humboldt Foundation     

A pointwise quasi-Newton method for unconstrained optimal control problems

Summary For a class of unconstrained optimal control problems we propose a quasi-Newton method that exploits the structure of the problem. We define a new type of superlinear convergence for sequences in function spaces and prove superlinear convergence of the iterates generated by the quasi-Newton method in this sense.This author supported by NSF grants # DMS-8300841 and # DMS-8500844     

A volume formula for hyperbolic tetrahedra in terms of edge lengths

We give a closed formula for volumes of generic hyperbolic tetrahedra in terms of edge lengths. The cue of our formula is by the volume conjecture for the Turaev-Viro invariant of closed 3-manifolds, which is defined from the quantum 6j -symbols. This formula contains the dilogarithm functions, and we specify the adequate branch to get the actual value of the volumes.     

A finite element lumped mass scheme for solving eigenvalue problems of circular arches

Summary This study is a continuation of a previous paper [4] in which the numerical results are given by using single precision arithmetic. In this paper, we show the numerical results which experess the sharper convergence properties than those of [4], by using double precision arithmetic.Dedicated to Prof. Masaya Yamaguti on the occasion of his 60th birthday