• Journal of Korean Society of Industrial and Systems Engineering
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• v.20 no.43
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• pp.299-319
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• 1997

Since a convergence strategy in interactive procedure is the origin of a lot of the restrictions and inconvenience of many methods, a new flexible convergence strategy is necessary for developing that is applicable for interactive MOLP as well as interactive multiple objective integer programming(MOIP). A method for computing the volume of the interval defined subsets of weighting vector space is developed using Sobol's LP$_{i}$, Generator. Since the interactive procedure requires a number of iterations, with a fixed number of solutions presented per iteration, a convergence strategy is needed to control the rate at which the interactive procedure converges to a final solution. Thus, in this paper, a new convergency strategy is developed.

• Information and Communications Magazine
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• v.21 no.4
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• pp.47-54
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• 2004

21세기에 접어들면서 통신서비스의 새로운 조류는 단연 "Convergence"이다. 기존의 서비스들은 개개의 서비스 매체에 따른 개별망을 통해 제공되어왔으나, 광대역 인터넷의 대중화로 인해 IP 기반으로 발전하고 있으며, 궁극적으로는 가입자 단말기, 유무선 액세스망, 서비스 핵심망, 서비스 플랫폼이 IP기반으로 발전될 전망이다. 이러한 통신 패러다임의 변화에 따라, 급변하는 통신환경의 변화에 적응하고 보다 다양한 멀티미디어 서비스를 하나의 공통된 Network하에 제공하고자 하는 움직임이 Broadband Convergency Network(BCN : 이하 BCN)이라고 할 수 있다. 따라서 궁극적인 광대역 통합망을 통한 멀터미디어 서비스 제공의 시발점은 광대역 IP망을 통한 음성 및 데이터 통합 서비스(이하 인터넷전화)라 볼 수 있으며 인터넷전화와 BCN은 분리시켜 생각할 수 없는 이유 중의 하나이다. 그러면 "인터넷전화로 시작되는 BCN은 사업자 및 이용자측면에서 어떠한 의미를 갖는가\ulcorner"를 살펴보기로 한다.(중략)

• The Transactions of the Korean Institute of Electrical Engineers
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• v.43 no.5
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• pp.739-746
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• 1994

This paper present an efficient methodology to solve the unit commitment problem for large scaled power system which involves various type of generation. We introduce the global optimization approach to coordinate the thermal type, hydro type and pumped storage type generation. To overcome the shortcomings in dynamic programming for thermal unit commitment, an improved heurisitic method using lambda(λ) was proposed, Hydro and pumped type allocation was Solved by analytical approach using λ which exculde undisirable iteration for satisfying the energy usage constraints. The case studies for proposed algorithm are proven by sample system and KEPCO practical system, which produced very resonable both computing requirements and convergency.

• Proceedings of the KIEE Conference
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• 2003.07d
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• pp.2088-2090
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• 2003

A practical recursive weighted least square(WLS) solution is proposed to solve the passive ranging problem. Apart from the previous works based on the extended Kalman filter(EKF), to ensure the convergency at long-range, the proposed scheme makes use of line-of-sight(LOS) rate instead of bearing information. The influence of LOS rate measurement errors is investigated and it is asserted that the WLS estimates contain bias and scale factor errors. Together with simple compensation algorithm, the estimation errors of proposed filter can be reduced dramatically.

• Proceedings of the KIEE Conference
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• 1996.11a
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• pp.130-132
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• 1996

The power flow calculations(PFc) are the most important and powerful tools in power systems engineering. The conventional power now problem is solved generally with numerical methods such as Newton-Raphson. The conventional numerical method generally have some convergency problem, which is sensitive to initial value, and numerical stability problem concerned with matrix inversion. This paper presents a new power flow calculation algorithm based on the genetic algorithm(GA) which can overcome the disadvantages mentioned above. Some case studies with IEEE 6 bus system also presented to show the performance of proposed algorithm.

• Proceedings of the KIEE Conference
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• 1993.07a
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• pp.117-119
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• 1993

This paper presents a new method for solving unit commitment problem including hydro and pumped storage hydro units in a large scale power system. The proposed method makes it possible to get variable power of hydro and pumped storage hydro units and results in the better unit commitment with good convergency. Moreover this paper proposes an unit commitment algorithm to consider variable power of these units effectively by Lagrangian Relaxation method. By applying the proposed method to the test system, it is verified the usefulness of this method.

• Proceedings of the KIEE Conference
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• 1993.07a
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• pp.192-194
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• 1993

This paper presents an efficient method for determining the economic dispatch of thermal generator using an alternative Jacobian matrix considering system constraints. The transmission loss is approximately expressed as a funtion of generating powers and the generalized generation factor. From this expression, the Jacobian matrix is formulated and solved by the Newton Raphson Method. In this method, the economic dispatch problem is solved rapidly without calculating the penalty factor. The proposed method has fast convergency characteristic and good accuracy. The feasibility of this method is demonstrated by means of examples.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.24 no.7
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• pp.907-915
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• 2000

The preconditioned Krylov subspace methods were applied to the incompressible Navier-Stoke's equations for convergence acceleration. Three of the Krylov subspace methods combined with the five of the preconditioners were tested to solve the lid-driven cavity flow problem. The MILU preconditioned CG method showed very fast and stable convergency. The combination of GMRES/MILU-CG solver for momentum and pressure correction equations was found less dependency on the number of the grid points among them. A guide line for stopping inner iterations for each equation is offered.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.604-607
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• 2005

The free vibration of solid circular plates has been studied using the differential transformation method(DTM). The effects such as mass at edge and elastic restraints have been considered. In order to avoid the singularity problem at the solid circular center two regularity conditions were applied with respect to the number of circumferential nodal line. The non-dimensional natural frequencies of the general circular plates were obtained for various boundary conditions. The results obtained by this method were compared with previous works. DTM showed fast convergency, accuracy, efficiency and validity in solving vibration problem of general circular plates.

• Structural Engineering and Mechanics
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• v.7 no.3
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• pp.289-302
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• 1999

An approximate method for analyzing the bending problems of irregular-shaped plates is proposed. In this paper irregular-shaped plates are such plates as plate with opening, circular plate, semi-circular plate, elliptic plate, triangular plate, skew plate, rhombic plate, trapezoidal plate or the other polygonal plates which are not uniform rectangular plates. It is shown that these irregular-shaped plates can be considered finally as a kind of rectangular plates with non-uniform thickness. An opening in a plate can be considered as an extremely thin part of the plate, and a non-rectangular plate can be translated into a circumscribed rectangular plate whose additional parts are extremely thin or thick according to the boundary conditions of the original plate. Therefore any irregular-shaped plate can be replaced by the equivalent rectangular plate with non-uniform thickness. For various types of irregular-shaped plates the convergency and accuracy of numerical solution by proposed method are investigated.