G.Palubeckis. Steepest Ascent: a Generalization of the Greedy Algorithm for the Maximum Clique Problem. Information technology and control, Kaunas, Technologija, 2003, No. 3(28), 7 - 13.
G.Palubeckis. Steepest Ascent: a Generalization of the Greedy Algorithm for the Maximum Clique Problem. Information technology and control, Kaunas, Technologija, 2003, No. 3(28), 7 - 13.In this paper, we describe a steepest ascent algorithm for the maximum clique problem. The algorithm comes from the unconstrained binary quadratic formulation of the problem and is a generalization of the well-known greedy heuristic. We also develop two variations of the iterated steepest ascent technique. We report computational experience on a set of standard benchmark graphs.
E.Bareiša, V.Jusas, K.Motiejūnas, R.Šeinauskas. A Simulation-Based Test Generation Method for Target Fault. Information technology and control, Kaunas, Technologija, 2003, No. 3(28), 14 - 20.In the area of automatic test pattern generation for sequential circuits both deterministic and simulation-based algorithms have been used. The main drawback of the deterministic methods is that they are defect-oriented, while in contemporary digital devices the diversity of the real physical defects is very wide. Fault simulation-based test generators can be easier adapted to new defects by using a fault simulator suitable for the new fault model. The weakness of simulation-based test generation approaches generally lies in an impossibility to identify undetectable faults due to absence of any deterministic test generation procedure. In addition, almost all deterministic, simulation-based methods and test pattern generation systems are related to certain specific circuit description level - either to gate level or to functional level. We propose a new simulation-based algorithm of test pattern generation for synchronous sequential circuits that is independent both from the circuit description level and defect type. Also, we prove that the proposed algorithm is exact - it either builds a test sequence that detects target fault or states that the target fault is undetectable.
V.Vaitkus, A.Gelžinis, R.Simutis. Decision Support System for Deflection Yoke Tuning. Information technology and control, Kaunas, Technologija, 2003, No. 3(28), 21 - 26.A high quality Deflection Yoke (DY) is one of the most important factors for a high quality monitor. The role of the deflection yoke is to deflect electron beams in horizontal and vertical directions. If the magnetic field of the DY is formed incorrectly, misconvergence of beams may occur resulting in blurred image on the screen of the monitor. The magnetic field of DY may be corrected by sticking one or several ferroelastic shunts on the inside surface of the deflection yoke. The tuning operators usually do this correction. Because of the process complexity the training of the tuning operators is long and expensive. Therefore, intelligent decision support systems for DY tuning are highly desirable in industry. This paper presents a fuzzy logic based system wich helps to identify the number of ferroelastic correction shunts and their positions during DY tuning process.
D.Levišauskas, V.Plaškutė. Optimization and Inferential Control of Biosurfactant Production in Fed-batch Culture "Azotobacter vinelandii". Information technology and control, Kaunas, Technologija, 2003, No. 3(28), 27 - 32.The paper deals with the optimization and control problems of biosurfactant production in fed-batch culture Azotobacter vinelandii 21 in order to maximize the yield of biosurfactant at the end of biotechnological process. Optimization problem is solved using hybrid model, consisting of mass-balance equations, kinetic equations for modeling the rates of biochemical transformations and artificial neural network for modeling the biosurfactant production rate. The calculated optimal feed-rate time profile can be realized as the process program control algorithm. In order to improve the process control under unpredictable variations of process behavior the inferential control algorithm, based on available on-line measurements of the process state variables, is developed and investigated via computer simulation.
G.Kazakeviciute, E.Januskevicius. Public Key Watermarking in Wavelet Domain. Information technology and control, Kaunas, Technologija, 2003, No. 3(28), 33 - 41.The paper describes a framework for public key watermarking and presents experimental results. Our scheme is based on wavelet transform and due to this reason could be included as a part of JPEG2000 or other wavelet based image compression standard. Our investigation is concentrated on finding the most reliable methods to include them into the proposed public key watermarking system.
A.Palevičius, M.Ragulskis, V.Kravčenkienė, R.Palevičius. The Influence of Perceptive Projection to the Analysis of the Holographic Interferograms of 3D Shell Type Structures. Information technology and control, Kaunas, Technologija, 2003, No. 3(28), 42 - 46.The inverse problem of reconstruction of motion from time average laser holographic holograms involves a complex and error sensitive procedure, especially if the analysed body is a 3-D shell type structure. Naturally, a straightforward interpretation of the pattern of fringes can lead to incorrect misleading results. Evaluation of the effects of perceptive projection helps to decrease the uncertainty of reconstruction.
The paper deals with the problem of segmentation of ischemic stroke in computer tomography images of the human brain. The thorough analysis of stroke regions in images shows up several useful features that can be used in early but rough image pre-processing stages. Based on these features a procedure for segmentation of ischemic stroke regions from 2D images into 3D shape is developed, presented and proved by experimentation. It can be used for evaluation of stroke volume and support the decision making about patient disability.
S.Balevičius, J.Novickij, A.Kačeniauskas, R.Kačianauskas, E.Stupak, N.Žurauskienė. Decoupled Algorithm for Coupled Magneto-mechanical Analysis of Coils by the FEM Software. Information technology and control, Kaunas, Technologija, 2003, No. 3(28), 54 - 61.The main purpose of this work is construction of the effective algorithm and user's utilities for magneto-mechanical analysis of stranded coils in FEM framework and ANSYS software by decoupling of magnetic and mechanical analysis. Proposed algorithm uses smaller data structures, especially for mechanical analysis and saves computational resources.
I.Katilius, I.Skučas, V.Melninkaitė. Simulation of Business Processes According to Petri Net Theory. Information technology and control, Kaunas, Technologija, 2003, No. 3(28), 62 - 66.Reengineering of business processes is a very hot subject of present days, but while implementing ERP systems we face with the absence of a mathematical model. The dynamical part of the model can be described by the entirety of management functions. Management functions describe what operation must be proceeded, how data should be changed. One of the tools allowing dynamic business process modeling is Petri net. Petri net is the formalism allowing analysis of the parallelism of the processes without an initial analysis of the parallel processes. Petri net helps to find out the integrated parts and functional models of organizations.
G.Liutkus, J.Budreckytė. Enhancement of Algorithms for Virtual Exposure. Information technology and control, Kaunas, Technologija, 2003, No. 3(28), 67 - 75.In this paper we describe possible enhancemens for the exposure algorithms. Major purpose of it is to map 2D-layout onto 3D-body. We proposed a couple of improvements to the existing data structures as well as triangulation algorithms. A lot of experimental results are provided in this paper as well.
E.Sakalauskas, T.Burba. Basic Semigroup Primitive for Cryptographic Session Key Exchange Protocol (SKEP). Information technology and control, Kaunas, Technologija, 2003, No. 3(28), 76 - 80.The construction of basic semigroup primitive for a cryptographic Session Key Exchange Protocol (SKEP) implementation is presented. The semigroup formalism for SKEP is known since 1993 and originates a new fundamental trend in cryptographic primitive's construction. The structure of a semigroup and its commutative subsemigroup as well are presented. The semigroup consists of functions that maps a finite set to itself. The commutative subsemigroups consist of a set of monogenic semigroups. The SKEP realization is presented in semigroup action level. The security of the protocol is based on hard solution of the Problems 1, 2 formulated by originators of cryptographic semigroup primitive. An expanded system of keys for initial keys distribution is presented.