N2 (18) April-June 2008 CONTENTS

Karpuk A.A. Algorithms for multivariate assignment problem (p. 5)

The multivariate assignment problem is considered. This problem is obtained from a classical assignment problem under the following additional assumptions: one applicant can be assigned to se-veral posts; assignments could lead to incompatibility between applicants. The multivariate assignment problem is NP-hard problem and is reduced to a problem of maximal full subhypergraph search with a minimal sum of weights of verteces and edges in a weighed n-partite hypergraph. For solving a multivariate assignment problem greedy algorithms and algorithms of local search in a neighbourhood of an initial solution are proposed.

Ivanov D.G., Kundas S.P., Lemzikov A.V. A mathematical model of the residual stresses formation process in steel pieces during induction hardening (p. 14)

The features of induction hardened steel pieces residual macrostresses are described. A mathematical model for simulation of stress-strained state of steel pieces under induction heating is proposed. The model includes such phenomena as a thermal and phase transformation deformations as well as phase transformation induced plasticity. The mathematical description is adapted for integrating with thermal and phase transformation calculations and allows to take into account the thermal dependencies of mechanical steel parameters. A computer implementation of algorithm is presented.

O.I. Eskova, I.I. Kikot Simulation inventory model in conditions of financial restrictions (p. 26)

The authors discuss investigation technology of inventory systems, based on simulation method. Financial restrictions are considered: discounts, crediting and non-stable behavior of percent rates.

Swed O.L. А dual description of elastic-viscoplastic process of material deforming (p. 35)

The correctness of the viscous stress tensor definition that is introduced as an admissible approximation is shown. The presentation of the process as two strain spaces that eliminates the influence of the elastic turns and allows to construct unambiguously the fluidity surface for elastic-viscoplastic material model is proposed.

Belozersky L.A. Modeling of remote sensing image histograms for object change analysis (p. 45)

Peculiarities and assumptions of remote sensing image histogram modeling methodology for object changes detection are considered and specified. Model identification methods are discussed. Model application for satellite images is demonstrated and directions of further research are discussed.

Gaiduk О.N., Gromyko G.F., Shnip A.I., Antanevish Y.A. Mathematical simulation of nonstationary rectification processes in gas oil vacuum hydroconversion plant (p. 54)

Nonstationary rectification processes in rectification towers are considered. A nonstationary mathematic model of rectification processes in rectification towers was developed for creation of a dynamic training simulator for gas oil vacuum hydroconversion plant. Rectification processes are considered together with hydrodynamics mathematic models describing fluid and gas motion, and heat and mass transfer models characterizing the transfer of heat and mass. Implicit finite difference schemes and realization algorithms for heat and mass transfer equations approximation are proposed. The results of computational experiment are presented.

Avdeev N.A., Bibilo P.N. Delay determination of regular circuits with serial connection of transistors (p. 69)

A problem of the delay determination of a regular circuit with serial connection of transistors is considered. The delay is suggested to be determined by SPICE simulation, the number of test vectors is minimized. An algorithm for rearranging the input wires of the circuits is proposed that provides decreasing the delay in a number of cases.

Ivaniuk A.A., Stepanov A.V. Functional random access memory faults injection into VHDL-projects of digital devices (p. 81)

A methodology to inject functional RAM faults into the VHDL-projects of digital devices is presented. An approach to describe the fault models and memory test algorithms using VHDL language is proposed. It is shown that the proposed methodology allows to evaluate the system’s behavior in case of the faults and to realize memory test algorithm verification.

Cheremisinova L.D. Topological optimization of regular MOS-structures by means of bipartite folding (p. 92)

The problem under consideration is to reduce the area of the layout of two-dimensional matrix RMOS structures of control logic of custom VLSI during the topological design. The bipartite folding of regular RMOS structures is used as the most suitable for structures of this type. Some restrictions imposed on the folding mode are formulated taking into account the peculiarities of structures consisting of MOS transistors. An efficient method is presented to find an optimal or near optimal solution of the task of bipartite column folding of regular RMOS structures.

Pottosin Yu.V., Toropov N.R., Shestakov E.A. Method for minimizing a system of completely specified boolean functions (p. 102)

A problem of minimization of a system of disjunctive normal forms (DNFs) that is given in a matrix form is considered. The criterion of minimization is the total number of different elementary conjunctions in the obtained DNF system. A technique to obtain the reduced DNF is described. A novel way to reduce this problem to the problem of the shortest covering is suggested that is based on a simple operation of set intersection. The results of testing the computer program are given.

Neudakh M.M., Zilbergleit M.A. Systematization of information characteristics of educational texts using cluster analysis (p. 111)

Clustering of 49 text information characteristics using a statistical package SPSS is described. The following group similarity measures were used: Euclidean distance, squared Euclidean distance, cosine of angle, correlation coefficient, Chebychev distance, city block distance, Minkowski distance. As a result of clusterization all attributes were partitioned into nine conditional groups. It is sufficient to use one attribute from each group for further processing.

Cherniavsky A.F., Chvarkova I.L., Sadov V.S. Key-schemes steadfastness in steganographic information embedding (p. 119)

The questions of steganographic steadfastness improvement of information protection using key schemes of data embedding are described. It was shown that it is possible to increase essentially the steadfastness by a proper choice of coding scheme and system parameters without significant decreasing steganographic channel capacity.

Likhoded N.A., Tolstikov A.A. Parallel versions of multi-dimensional loop nests (p. 129)

Conditions for the parallelization of loop nests by slight modification of initial codes are stated. Processor capacity and a problem of computation grain choice are investigated.

Yakimau A.I. Technology of software package BelSim modernization for organization of distributed calculations (p. 137)

A modernization of software package on the basis of MPI-technology for distribution of calculations is offered. Multiple use of simulation technologies, distributed calculations and XML-technologies allow to build a software package for imitations of complex systems integrated into automated information system of industrial enterprise.

Arkadij Dmitrievich Zakrevskij (On his 80th birthday) (p. 143)

Evguenij Alexandrovich Starodetko – one of the pioneers of CAD (p. 146)