• The Transactions of the Korean Institute of Electrical Engineers
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• 제34권8호
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• pp.308-316
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• 1985

This paper proposes an analytic tool for long-term generation expansion planning based on the maximum principle. Many research works have been performed in the field of generation expansion planning. But few works can be found with the maxinmum principle. A recently published one worked by professor Young Moon Park et al. shows remarkable improvements in modeling and computation. But this modeling allows only thermal units. This paper has extended Professor Park's model so that the optimal pumped-storage operation is taken into account. So the ability for practical application is enhanced. In addition, the analytic supply-shortage cost function is included. The maximum principle is solved by gradient search due to its simplicity. Every iteration is treated as if mathematical programming such that all controls from the initial to the terminal time are manipulated within the same plane. Proposed methodology is tested in a real scale power system and the simulation results are compared with other available package. Capability of proposed method is fully demonstrated. It is expected that the proposed method can be served as a powerful analytic tool for long-term generation expansion planning.

• Transactions of the Korean Society of Mechanical Engineers A
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• 제26권12호
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• pp.2631-2635
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• 2002

The semi-analytic sensitivity analysis using Pade approximation is presented for linear elastic structures. Although the semi-analytic method has several advantages, accuracy of the method prevents it from practical application. One of promising remedies is the use of geometric series for the matrix inversion. Though series expansion of order three has been successfully applied to the calculation of the structural sensitivity in the most range of the design perturbation, it is prone to have a slow convergence for large perturbation. To overcome this shortage, Pade approximation is introduced so that it can broaden the trust region of the perturbation without adding expansion terms. Numerical results show that the confident sensitivity can be obtained with tiny expenses of computation effort.

• Steel and Composite Structures
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• 제31권6호
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• pp.591-600
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• 2019

Based on the energy-variational principle, a coupling vibration analysis model of high-speed railway simply supported beam bridge-track structure system (HSRBTS) was established by considering the effect of shear deformation. The vibration differential equation and natural boundary conditions of HSRBTS were derived by considering the interlayer slip effect. Then, an analytic calculation method for the natural vibration frequency of this system was obtained. By taking two simply supported beam bridges of high-speed railway of 24 m and 32 m in span as examples, ANSYS and MIDAS finite-element numerical calculation methods were compared with the analytic method established in this paper. The calculation results show that two of them agree well with each other, validating the analytic method reported in this paper. The analytic method established in this study was used to evaluate the natural vibration characteristics of HSRBTS under different interlayer stiffness and length of rails at different subgrade sections. The results show that the vertical interlayer compressive stiffness had a great influence on the high-order natural vibration frequency of HSRBTS, and the effect of longitudinal interlayer slip stiffness on the natural vibration frequency of HSRBTS could be ignored. Under different vertical interlayer stiffness conditions, the subgrade section of HSRBTS has a critical rail length, and the critical length of rail at subgrade section decreases with the increase in vertical interlayer compressive stiffness.

• Transactions of the Korean Society of Mechanical Engineers
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• 제19권4호
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• pp.941-949
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• 1995

An efficient method based on analytic solutions is applied to solve anti-plane Mode III crack problems. The analytic technique developed earlier by the present authors for Laplace's equation in a simply-connected region is now extended to general Mode III crack problems. Unlike typical numerical methods which require fine meshing near crack tips, the present method divides the cracked bodies, typically non-convex or multiply-connected, into only a few super elements. In each super element, an element stiffness matrix, relating the series coefficients of the traction and displacement, is first formed. Then an assembly algorithm similar to that used in the finite elements, is first formed. Then an assembly algorithm similar to that used in the finite elements, is developed. A big advantage of the present method is that only the boundary conditions are to be satisfied in the solution procedure due to the use of analytic solutions. Several numerical results demonstrate the efficiency and accuracy of the present method.

• Proceedings of the Safety Management and Science Conference
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• 대한안전경영과학회 2005년도 춘계학술대회
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• pp.39-44
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• 2005

Process control and autonomous safety control by applying PSM(Process Safety Management) method using AHP(Analytic Hierarchy Process) and to development of PSIM(Process Safety Information Management) evaluation method in the construction. The reason why PSIM method should be quantitative and substantial progress is because it contributes Korean constructing companies to enhancing their safety control ability and to taking an equal stance just like developed countries, thereby strengthening their competitive edges.

• Journal of the Korean Society for Precision Engineering
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• 제17권9호
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• pp.174-180
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• 2000

A reliable analytic model that determines the cross sectional shape of a workpiece(material) in round-oval(or oval-round) pass sequence has been developed. the cross sectional shape of an outgoing workpiece is predicted by using the linear interpolation of the radius of curvature of an incoming workpiece and that of roll groove to the roll axis direction. The requirements we placed on the choice of the weighting function were to ensure boundary conditions specified. The validity of the analytic model has been examined by hot rod rolling experiment with the roll gap and specimen size changed. The cross sectional shape and area of a workpiece predicted by the proposed analytic model were good agreement with those obtained experimentally. It was found that the analytic model has not only simplicity and accuracy for practical usage but also save a large amount of computational time compared with finite element method.

• The Transactions of the Korean Institute of Electrical Engineers B
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• 제48권6호
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• pp.309-315
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• 1999

Coupling loss is generated by the time-varying external magnetic field in the normal matrix of the multi-filamentary HTS tape. This paper calculates the coupling loss in the HTS tape. Analytic calculation of the coupling loss cannot consider the effect of the different shapes and the arrangement of the filaments. Numerical calculation by using finite element method and analytic calculation of the coupling loss have been done in this paper and results of two calculations have been compared. Transverse magnetic field and longitudinal magnetic field were considered as the external field.

• Journal of Korean Society of Industrial and Systems Engineering
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• 제28권4호
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• pp.7-13
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• 2005

Many domestic studies related to service quality are performed but the study on computing Service Quality Score is not yet activated. Because Service quality measurement plays an important role in assessing service performance and diagnosing service problems, it is very important that service quality is measured exactly. Therefore this study offered realistic approach method for computing Service Quality Score by using T.L. Saaty's Analytic Hierarchy Process technique. That is, Service Quality Score of this study is computed by using customer's priority(weights) for five dimensions(Tangible, Reliability, Assurance, Responsiveness, Empathy). This method is more realistic than the existing method computed by an arithmetical average of dimension's variables.

• Journal of Industrial Technology
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• 제25권A호
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• pp.75-80
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• 2005

A trapezoidal fin is analyzed by using one-dimensional analytic method. For two boundary conditions, the heat transfer rate is given instead of specified temperature at the fin base and heat conduction into the fin tip is equal to heat convection from the tip. Temperatures at three different points within the trapezoidal fin are measured by using experimental apparatus. A comparison of the temperature between one-dimensional analytic method and experimentation is made as a function of dimensionless fin length under both free convection and forced convection conditions. The ratio of heat loss from the fin tip surface to that through the fin base is presented as a function of dimensionless fin length and Biot number. One of results shows that the relative error increases as the air velocity increases for forced convection conditions.

• Industrial Engineering and Management Systems
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• 제1권1호
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• pp.93-98
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• 2002

It is important to evaluate the performance of candidates mathematically from various aspects, and reflect it on decision making. In decision making, we judge the candidates through two steps, classification of objects and comparison of objects or candidates with plural elements. In the former step, Analytic Hierarchy Process (AHP) is useful method to evaluate candidates from plural viewpoints, and in the later step, Data Envelopment Analysis (DEA) is also useful method to evaluate candidates with plural categorized data. In fact, each candidate has plural elements, nevertheless it has been more important to evaluate from various aspects in IT society. So, we propose a new procedure complementing AHP with DEA.