• Journal of the Korean Operations Research and Management Science Society
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• v.6 no.2
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• pp.35-49
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• 1981

This paper is concerned with developing a Multi-period Behavioral Model for the portfolio selection problem. The unique feature of the model is that it treats a number of factors and decision variables considered germane in decision making on an interrelated basis. The formulated problem has the structure of a Chance Constrained programming Model. Then empoloying arguments of Central Limit Theorem and normality assumption the stochastic model is reduced to that of a Non-Linear Programming Model. Finally, a number of interesting properties for the reduced model are established.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.173-178
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• 2001

The cost on transmission and election of precast concrete members largely depends on the weight of them. In this study, the weight of prestressed precast beam could be reduced by control the section and prestressing force to meet the required strength on the basis of the optimum process. The top and bottom concrete stress of the section considered is required to check according to each construction step for this process. The original rectangular beam weight could be reduced up to 50~39% due to the development of a U-beams from the optimum process.

• Journal of the Korean Operations Research and Management Science Society
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• v.7 no.1
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• pp.11-16
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• 1982

A method is described for the solution of a linearly constrained program with parametric nonlinear objective function. The algorithm proposed in this paper may be regarded as an extension of the simplex method for parametric linear programming. Namely, it specifies the basis at each stage such that feasibility ana optimality of the original problem are satisfied by the optimal solution of the reduced parametric problem involving only nonbasic variables. It is shown that under appropriate assumptions the algorithm is finite. Parametric procedures are also indicated for solving each reduced parametric problem by maintaining the Kuhn-Tucker conditions as the parameter value varies.

• Journal of the Chungcheong Mathematical Society
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• v.35 no.3
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• pp.205-225
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• 2022

In this paper, we derive analytical closed results for the first (a, b)-KA index, the Sombor index, the modified Sombor index, the first reduced (a, b)-KA index, the reduced Sombor index, the reduced modified Sombor index, the second reduced (a, b)-KA index and the mean Sombor index mSO_α for the OTIS biswapped networks by considering basis graphs as path, wheel graph, complete bipartite graph and r-regular graphs. Network theory plays a significant role in electronic and electrical engineering, such as signal processing, networking, communication theory, and so on. A topological index (TI) is a real number associated with graph networks that correlates chemical networks with a variety of physical and chemical properties as well as chemical reactivity. The Optical Transpose Interconnection System (OTIS) network has recently received increased interest due to its potential uses in parallel and distributed systems.

• The Transactions of the Korea Information Processing Society
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• v.4 no.11
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• pp.2690-2700
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• 1997

This paper presents parallel sorting algorithm, SHARED-MEMORY-BS and REDUCED-BS, which are implemented on shared-memory parallel computers. These algorithm sort N keys in $O(log^2N)$ time. REDUCED-BS users a parity strategy which gives an idea for the efficient usage of the local memory associated with each processor. By taking advantage of the local memory associated with each processor, the communication of REDUCED-BS is decreased by approximately half that of SHARED-MEMORY-BS. On the basis of alleviating the communication, the algorithm REDUCED-BS results in a significant improvement of performance.

• International Journal of Control, Automation, and Systems
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• v.3 no.2
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• pp.217-224
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• 2005

Generally, the underwater flight vehicle (UFV) depth control system operates with the following problems: it is a multi-input multi-output (MIMO) system because the UFV contains both pitch and depth angle variables as well as multiple control planes, it requires robustness because of the possibility that it may encounter uncertainties such as parameter variations and disturbances, it requires a continuous control input because the system that has reduced power consumption and acoustic noise is more practical, and further, it has the speed dependency of controller parameters because the control forces of control planes depend on the operating speed. To solve these problems, an adaptive fuzzy sliding mode controller (AFSMC), which is based on the decomposition method using expert knowledge in the UFV depth control and utilizes a fuzzy basis function expansion (FBFE) and a proportional integral augmented sliding signal, is proposed. To verify the performance of the AFSMC, UFV depth control is performed. Simulation results show that the AFSMC solves all problems experienced in the UFV depth control system online.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.7 no.4
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• pp.205-211
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• 2014

This paper addresses the framework of object-oriented image coding, describing a new algorithm, based on monodimensional Legendre polynomials, for texture approximation. Through the use of 1D orthogonal basis functions, the computational complexity which usually makes prohibitive most of 2D region-oriented approaches is significantly reduced, while only a slight increment of distortion is introduced. In the aim of preserving the bidimensional intersample correlation of the texture information as much as possible, suitable pseudo-bidimensional basis functions have been used, yielding significant improvements with respect to the straightforward 1D approach. The algorithm has been experimented for coding still images as well as motion compensated sequences, showing interesting possibilities of application for very low bitrate video coding.

• Transactions of Materials Processing
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• v.27 no.1
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• pp.28-36
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• 2018

Electromagnetic forming is a type of high-speed forming process to deform a workpiece through a Lorentz force. As the high strain rate in an electromagnetic-forming simulation causes infeasibility in determining constitutive parameters, we employed inverse parameter estimation in the previous study. However, the inverse parameter estimation process required us to spend considerable time, which leads to an increase in computational cost. To overcome the computational obstacle, in this research, we applied two types of surrogate modeling methods and compared them to each other to evaluate which model is best for the electromagnetic-forming simulation. We exploited an artificial neural network and we reduced-order modeling methods. During the construction of a reduced-order model, we extracted orthogonal bases with proper orthogonal decomposition and predicted basis coefficients by utilizing an artificial neural network. After the construction of the surrogate models, we verified the artificial neural network and reduced-order models through training and testing samples. As a result, we determined the artificial neural network model is slightly more accurate than the reduced-order model. However, the construction of the artificial neural network model requires a considerably larger amount of time than that of the reduced-order model. Thus, a reduced order modeling method is more efficient than an artificial neural network for estimating the electromagnetic forming and for the rapid approximation of structural simulations which needs repetitive runs.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.35-36
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• 2006

This paper presents an effective multiplier in GF($2^m$) based on programmable cellular automata (PCA) and uses a normal basis. The proposed architecture has the advantage of high regularity and a reduced latency. The proposed architecture can be used in the effectual hardware design of exponentiation, division, inversion architectures.

• Tribology and Lubricants
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• v.4 no.1
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• pp.43-55
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• 1988

A Study on the effect of the additives in lubricating oil was investigated on the basis of the thermal activated wear theory in terms of their wear behaviours, using four ballwear machine. The sample oils, which included diethyl-3, 5-di-t-butyi-4-hydroxy-benzyl phosphonate (DEP), ZDDP and TCP additives respectively, showed distinct wear characteristics depending upon the bulk oil temperature and the sliding velocity. The newly synthesized additive, viz., DEP showed excellent antiwear performance cornpared with the conventional additives, ZDDP and TCP. On the basis of the experimental results, it is reduced that the wear mechanism of the conventional additives, viz., ZDDP and TCP is the protective film formation and their antiwear capability is depending upon the shearing strength of the film formed. On the other hand, the new additive, DEP showed that the secondary activation energy was much eliminated and so, the thermal instability was reduced by the hydrogen scavenging reaction of the new additive, which was virtually an endothermic reaction process.In conclusion, a new concept of antiwear mechanism is estabilished and testified. And new chemical, which showed the function of hydrogen and free radical scavenging role, is synthesized and introduced as the new, highly antiwear effective lubricating oil additive.