• The Transactions of the Korean Institute of Electrical Engineers A
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• v.54 no.11
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• pp.507-517
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• 2005

This paper presents the results of critical contingency analysis for the Korean power system which is performed to identify the impact of the critical contingencies on the Korean power system and set up a short term system operation planning for the purpose of preventing large scale blackout. The static and dynamic simulation is carried out for each critical contingency and the simulation results for each contingency are shown under the peak load condition for the year 2005, 2007 and 2010.

• 한국연소학회:학술대회논문집
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• 2012.04a
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• pp.35-36
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• 2012

Part load operation usually covers large periods of the total operation time on the economic ground and electricity demand in small-scale boilers. Performance analysis of part load behavior is very important for the purpose of boiler operation optimization. A simple thermal calculation approach is applied to predict performance of a pilot-scale circulating fluidized bed (CFB) boiler at part load operation. Verification has been carried out by comparing between calculation results an operation data of the boiler.

• The Transactions of the Korean Institute of Power Electronics
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• v.20 no.1
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• pp.59-64
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• 2015

This paper proposes an analysis and operation strategy of a grid-connected wind turbine system using a diode rectifier. The currents of generators are the same as that of a small wind turbine system. Therefore, the analysis of generator torque is required as opposed to an analysis of blade speed. In this paper, the appropriate MPPT control method is proposed to control generator torque. Usefulness of the proposed operation strategy is verified by simulations and experiments.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.636-641
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• 2008

In this paper, the analysis methods of available information are reviewed and it is elicited to the method of which the analysis results are applied to the Autonomous Decentralized Train Management System for the optimization at the point of the route control time and for making the efficiency shunting plan in the Autonomous Centralized Station Operation Control System. As the statistics and estimated information which are got through the utilizable information analysis are applied for the automatic route control function and the shunting plan management of the station operation control system, it is possible to use efficiently the station information by the autonomous route control system. And as the exact forecast information needed for the shunting plan establishment and the operation is provided to the operator, it is established to the efficient train operation plan.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.5
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• pp.102-107
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• 2014

Because of high oil prices and emission gas problems, many governments tighten regulation of fuel economy and emission gas. For Passenger car, there are many researches for plug-in hybrid electric vehicles and they are being manufactured. On the other hand, there are few researches for plug-in hybrid electric bus that is heavy commercial vehicle. In this study, analysis of fuel economy for series plug-in hybrid electric bus according to engine operation strategy based on simulation is conducted. Forward simulator is developed using Autonomie. Engine operation strategies consist on constant engine operation strategy and engine on/off operation strategy. Considering the engine operation strategy, results of vehicle speed, engine operating points and fuel economy are obtained and analyzed. As a result, engine on/off operation strategy has more advantage than constant engine operation strategy in terms of fuel economy.

• The KSFM Journal of Fluid Machinery
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• v.15 no.6
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• pp.18-24
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• 2012

This study simulated the operation of a steam injected gas turbine combined heat and power (CHP) system. A full off-design analysis was carried out to examine the change in the turbine blade temperature caused by steam injection. The prediction of turbine blade temperature was performed for the operating modes suggested in the previous study where the limitation of compressor surge margin reduction was analyzed in the steam injected gas turbine. It was found that both the fully injected and partially injected operations suggested in the previous study would cause the blade temperature to exceed that of the pure CHP operation and the under-firing operation would provide too low blade temperature. An optimal operation was proposed where both the turbine inlet temperature and the injection amount were modulated to keep both the reference turbine blade temperature and the minimum compressor surge margin. The modulation was intended to maintain a stable compressor operation and turbine life. It was shown that the optimal operation would provide a larger power output than the under-firing operation and a higher efficiency than the original partially injected operation.

• Journal of Nutrition and Health
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• v.39 no.4
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• pp.417-425
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• 2006

The purpose of this study were to a) investigate operation of human resource in contract foodservice management company (CFMC), b) identify the staffing indices for the establishment an labor productivity for CFMC, and c) develop standardized model of staffing demand as foodservice's scale in CFMC. The data was collected using FS intra-net system from 138 contract-managed foodservice operations in A CFMC and statistical analysis was completed using the SAS/win package (ver. 8.0) for description analysis, ANOVA, Duncan multiple comparison, pearson correlation analysis, and regression analysis. The types of operation were included factory (45%), small scale operation (26%), office (11%), department store (10%), training institute (4%), and hospital (3%). The distribution of foodservice scale was classified by meal served was as follows; 'less than 500 meals (47%)', 'from 500 to 1500 meals (25%)', 'from 1500 to 2500 meals (17%)', and 'more than 2500 meals (12%)'. There was two types of contract method, fee-contract (53%) and profit-and-loss contract (46%) Some variables were significantly high operation indices such as selling price, food cost, monthly sales, net profit and others were significantly low operation indices such as labor, meal time a day in the small foodservice on meal scale (p<.001). The more foodservice was large, the more human resource was disposed on dietitian, cook, cooking employee altogether (p<.001). Foodservice in A CFMC was divided into 2 groups by 500 meals a day, according to comparative analysis of labor productivity as meal scale per working hour, meal scale a day and operation indices as meal per foodservice employee, meal per cooking employee (p<.001). The regression equation model was developed as 'the number of employees=1.82+0.014 ${\times}$ meal served' in the operation of less than 500 meals, 'the number of employees=9.42+0.013 ${\times}$ meal scale a day -0.94 ${\times}$ meal scale per working hour' in the operation over 500 meal scale using labor productivity indices and operation indices. Therefore, CFMC could be enhanced efficiency of human resource arrangement using the standardized model of staffing demand and would be increased effectiveness of profit.

• Architectural research
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• v.7 no.1
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• pp.11-18
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• 2005

In today's building industry the emphasis has been geared more towards construction, thus building maintenance and life cycle have been neglected until now. A direct result of this neglect is the rapid aging of building, which leads to more cost-effective decision making methods for the prolongation of building life span. The following study is conducted in the area of Daegu and Seoul in order to develop the estimation analysis method of the annual operation cost of the Korean high-rise condominiums for the cost-effective decision making support through mathematical and statistical analyses including the present value and standardized measurement corrections. Based on the assumption that the life expectancy of the high rise condominium is 50 years, initial cost is ￦421,212/$m^2$, and a total sum of yearly operation cost during life expectancy is ￦2,154,499//$m^2$), yearly accumulated operation cost is shown as below: $AOC=0.7097t^4-38.803t^3+806.95t^2+11045t-496.52$ ($R^2=0.98$) (Here, AOC = Accumulated Operation Cost, t = given years)

• Bulletin of the Korean Space Science Society
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• 2003.10a
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• pp.108-108
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• 2003

본 논문에서는 과학위성 2호의 주 탑재체인 LIST의 Operation에 대한 개념을 소개하고자 한다. LIST는 태양 진공자외선(Lyman-$\alpha$)의 full disk 영상을 획득하고 분석함으로서 채층과 전이영역의 구조와 진화, ‘Quiet Sun’의 진공자외선 복사 변화 모델, 그리고 태양 진공자외선의 복사로 인한 지구 고층 대기의 변화를 밝혀내는 것이 목표이다. 이러한 목표를 성공적으로 수행하기 위해서는 LIST Operation 개념의 정립과 철저한 규정이 필요하다. 따라서 본 연구진은 Operation을 크게 두 부분으로 세분하였다. 즉, LIST의 각 구성 요소들이 유기적으로 작용, 목적하는 데이터의 성공적인 획득을 위한 ‘Technical Operation’과 획득된 데이터를 활용하여 효과적으로 분석하고 목적한 과학적 성과를 달성하기 위한 ‘Scientific Operation’으로 구분하여 규정하였다. 또한 효율적인 Data System의 관리를 위해 데이터의 흐름을 ‘LIST Observing System’, ‘LIST Data Acquisition System’, ‘LIST Data Reduction and Analysis’, 그리고 ‘LIST Data Analysis and Publication’의 네 가지 단계로 나누어 Data의 활용 중에 나타날 수 있는 위험들을 최소화 하고자 하였다.

• Journal of Information Technology Services
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• v.14 no.4
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• pp.31-44
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• 2015

Local governments in Korea are involved in three types of online shopping sites : 'direct operation', 'outsourced operation', and 'sales agency.' They are different in terms of the site operator and the charging mechanism among a local government, the site operator, and local producers. This study analyzes their differences in site traffic, local producers' participation, promotion, and partnership. The results from the investigation of 72 shopping sites are the following. First, shopping sites of the 'direct operation' type and the 'outsourced operation' type show significantly higher participation of local producers. Second, the 'marketing agency' type has significantly higher number of promotional activities than the 'oursourced type' which has significantly higher number than the 'direct operation' type. Third, the number of partnerships in the 'marketing agency' type is the highest. The 'direct operation' type is the second and significantly higher than the 'outsourced type.' On the basis of the analysis results, this paper suggests an incubation ecosystem model as a better way of involvement by local governments in online shopping sites.