• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.17 no.5
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• pp.427-435
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• 2005

This paper investigates the thermal storage performance of the office building which has adopted an air conditioning system with its slab structure as a regenerator. Four cases of the thermal storage performance experiment were conducted. Room air temperatures, floor slab temperatures, temperatures around the air conditioning unit were logged and analyzed. The load handling capacity of the air conditioning unit and the amount of heat stored in the slab were decided from those experiments. Several efficiencies were investigated to evaluate the performance of the thermal storage. The results concluded that the slab as a regenerator is very effective in cutting down peak loads of the office building.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.25 no.4
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• pp.40-45
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• 2002

An AS/RS construction cost minimization model under throughput rate requirement constraint has been developed, whose objective function includes S/R machine cost, storage rack cost, and interrace conveyor cost. S/R machine cost is a function of the storage rack height, the unit load weight, and the control logic used by the system, while storage rack cost is a function of the storage rack height, the weight and the volume of the unit load. Since the model is a nonlinear integer programming problem which is very hard to solve exactly with large problem size, a solution procedure is developed to determine the height and the length of the storage rack with a fixed number of S/R machines, while increasing the number of S/R machines one by one to meet the throughput rate requirement.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.37 no.10
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• pp.675-682
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• 1988

An improved algorithm for optimal daily hydrothermal unit commitment is proposed in this paper. Especially, for the purpose of guarantee on the existence of feasible solution all the time, the secondary states as well as the primary state are considered at each step in the procedure of solution by Hybird Dynamic Programming to solve the problem of which solution may not exist due to the increased number of constraints to be taken into account. The computational problem which may be caused in the course of considering secondary policies through whole steps of the period examined is solved by the heuristic judgement in every step taking load variation rates into account. The effectivness of the algorithm has been demonstrated by applying it to a sample power system.

• Journal of Korean Institute of Industrial Engineers
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• v.29 no.3
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• pp.222-229
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• 2003

In this paper, we address a layout design problem, PTN[2], for determining an appropriate 2-class-based dedicated storage layout in a class of unit load storage systems. Our strong conjecture is that PTNI2] is NP-hard. Restricting PTN[2], we provide three solvable cases of PTN[2] in which an optimal solution to the solvable cases is one of the partitions based on the PAI(product activity index)-nonincreasing ordering. However, we show with a counterexample that a solution based on the PAI-non increasing ordering does not always give an optimal solution to PTN[2]. Utilizing the derived properties, we construct an effective heuristic algorithm for solving PTN[2] based on a PAI-non increasing ordering with performance ratio bound. Our algorithm with O($n^2$) is effective in the sense that it guarantees a better class-based storage layout than a randomized storage layout in terms of the expected single command travel time.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.34 no.6
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• pp.220-229
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• 1985

This paper proposes a new optimal unit commitment algorithm for the rational operation of electric power systems. Especially, the algorithm is improved by considering transmission line capacity limits and load forecasting uncertainty with the consideration of the participation factors of each units, so that the method becomes more reliable and flexible one. The transmission losses are considered by using updated penalty factors obtained from the constant matrixes of the fast decoupled load flow method, the system loads are distributed at each buses, and the several necessary operational constraints are also considered for the purpose of presenting a more practicable scheme. Finally, the effectiveness of the proposed algorithm has been demonstrated by applying to the 23-bus model system.

• Journal of Korean Society on Water Environment
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• v.23 no.5
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• pp.620-627
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• 2007

In this study a general analysis method for watersheds with the entire runoff conditions and corresponding water quality is proposed and its applicability based on the currently available information is investigated. Using the 8-day-interval data set of runoff and water quality observed by Nakdong River Environment Research Center, the flow duration curve and discharge-load relation curve for each unit watershed are established, then the load duration curve is finally constructed. This paper discusses how the load duration curve can be used in the assessment of TMDL. The entire Nakdong river watershed is also divided into prior managing areas of point sources or non-point sources in a way of general management. It is thought that LDC can be a great tool for visualizing overall probabilities of current water quality and thus for the TMDL management.

• 전기의세계
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• v.24 no.2
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• pp.84-91
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• 1975

This paper describes the results of a study for the system characteristics, especislly for the abnormal frequency drop of power system, when a large generation unit such as Kori Nuclear 1 (595MW) pulls out from the system. The automatic load shedding method now adopted in our system was re-studied to ameliorate the above problem. From the results of the study, a new under-frequency relay with an element for detecting the slope of frequency change and with time delay element to raise the lowered frequency to a desired value, was found to be effective, and should be purchased and utilized. By this study, an optimal and concrete load shedding method was recommended for reliable operation of power system.

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.432-434
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• 1997

In order to find the steady-state operating condition of HVDC system interacting with AC power system, the load flow calculation of AC/HVDC system is performed. For the calculation, each generating unit is modeled by an equivalent voltage source and coupled impedance. The rectifier station is modeled by a controlled DC voltage source. EMTP simulation of the AC/HVDC system is also performed to verify the result of the load flow calculation.

• Pallet News
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• s.51
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• pp.15-19
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• 2008

본 내용은 지난 10월 23일 대한상공회의소에서 있었던 한 중 일 아시아 유닛로드시스템 컨퍼런스 발표자로써 중국물류구매연합회 파렛트전문위원회 오청일 주임이 발표한 내용입니다.

• Pallet News
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• s.65
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• pp.5-14
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• 2012

원고는 지난 2011년 11월 11일 기술표준원 중강당에서 열린 "2011 유닛로드시스템 컨퍼런스"의 발표원고로 아시아파렛트시스템연맹(APSF) 서병륜 회장이 발표하였습니다.