• 한국물환경학회지
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• 제22권5호
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• pp.905-912
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• 2006

In this paper, simulation methods of the system dynamics model developed by Das et al. (1997) for activated-sludge wastewater treatment plants are illustrated in an attempt to determine the operating rules and the policies related to capacity expansion of an activated-sludge wastewater treatment plant. For existing conditions, the analyses were performed by varying activated-sludge return rate to observe changes in effluent water quality and treatment efficiency. The effluent water quality is also analyzed for various average daily inflow conditions and activated-sludge return rates. As a result, without expanding the aeration tank, maximum average daily inflow that can satisfy the effluent water quality standard of BOD $0.02kg/m^3$ was determined as $2,840m^3/hr$, subject to 100% of activated-sludge return rate while other factors remain constant. When the activated-sludge return rate is less than 100%, expansion of the aeration tank is necessary and minimum sizes of the aeration tank to satisfy the effluent water quality standard were determined for various activated-sludge return rates. In addition, the total operating and maintenance as well as unit treatment cost regression equations for activated-sludge wastewater treatment plants are suggested by using the cost data that are obtained from Water and Wastewater Division, Ministry of Environment. The regression analyses showed that the economies of scale phenomena exist in the operating and maintenance costs of activated-sludge wastewater treatment plants.

• 한국건설안전학회 논문집
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• 제2권2호
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• pp.76-81
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• 2019

무인타워크레인의 운전자격 취득이 쉬워지고 불법개조가 늘어나며 소규모 건설현장에서도 무인타워크레인이 점차 활용되고 있다. 그러나 운전경험이 부족한 타워크레인 운전자의 문제가 커지면서 안전사고도 늘고 작업자도 사고위험에 노출되고 있다. 본 연구에서는 무인타워크레인 사고를 분석하여 사고 원인을 도출하였다. 그 후, 사고 원인의 중요도를 도출하기 위해 AHP 기법을 사용하여 분석하였다. 이 연구의 결과는 무인타워크레인을 사용하는 사업자와 건설 노동자들이 작업 규칙을 따르지 않는다는 것이다.

• 한국도서관정보학회지
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• 제12권
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• pp.133-160
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• 1985

In college or university libraries, the data of dissertations is one of the important academic information data. But traditional cataloging rules of dissertations and the method of operation is not only didn't unify but also fit to actual circumstances of library. This reason make librarians waste of time and the situation about piling up of unprocessed data don't make library services properly. In this papers, to analyze the above mentioned problems, I have investigated with questionaries about actual examples of construction methods of call number and item describing form of dissertations which is being used now in every college library in Korea. With the replied 61 questionaries which was compared with and investigated to merits and faults about library itself, I have showed revision ways. The characteristics of the revision ways are the followings. 1) Deleted informal and unmeaning descriptions and simplified describing. 2) Recommended to operating one or two kinds describing items which are only necessary. 3) Made call number specifically and then it make us easy to identify data and simultaneously call number can do its original action. 4) shelving range of data is made to colleges, years, departments, majors but in same departments, author's name is recommended by Korean alphabetical ordering. Besides, for proper and systematic management and operating of data. It must be necessary to recommend that reading systems of closed shelves type, incoming and outgoing and shelving by fulltime exclusive charged librarian, separate management of items and data are recommended.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1991년도 하계학술대회 논문집
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• pp.738-743
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• 1991

A multiobjective analysis technique was applied for the optimum operation of pumps and reservoirs in service water transmission systems. Three major objectives were identified and assessed on the normally operating service water transmission systems. They are, 1) stability of pump operation; 2) economic point of view in minimizing the energy cost for pumping; 3) reliability in meeting the stochasticaly varying demands. The measures of these objectives were required times of pump on-offs in stability, required total energy cost in economics, and minimum required storage during the operating horizon in reliability. In order to find the best meeting solution to the decision maker, a set of non-dominated solutions which show the tradeoff relationships between the considering objectives were generated. The DM selects the best solution from this explicit tradeoff relationships using his heuristic decision rules or experience. The theory was verified by applying to the Kumi Service Water System. A combined technique of the ${\varepsilon}-constraint$ and the weighting methods was used to generate the nondominated solutions, and the dynamic programming algorithm was applied to find the optimal solution for the discretized multi-objective analysis problems.

• 전기학회논문지
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• 제57권11호
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• pp.1922-1928
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• 2008

The thermal rating of a conductor are maximum continuous current capacity and short time emergency current capacity. The overload operation for a faults have an effect on a conductor lifetime. Its time duration and overload level are limited to facility conditions of transmission lines. The short time emergency current capacity in KOREA observe the KEPCO's DESIGN RULE 1210, but its rules are not included to concept of an allowable short time duration. This papers are described to the calculation concept of short time emergency current capacity considering a time duration and an overload level. And we suggested a operation grouping and its maximum conductor temperature considering facility conditions - conductor lifetime, stability of connection points, conductor height above ground and clearance, in the operating and new T/L.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.173-175
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• 2004

This paper presents a novel design of a self tuning PI controller of induction motor using fuzzy control. In this approach, the fuzzy tuning of a PI controller gains is achieved through fuzzy rules deduced from many robustness simulation tests applied to several induction motors, for a variety of operating conditions such as response to speed command from standstill, step load torque application and speed variations, with nominal parameters and an changed rotor resistance, self inductance and inertia. Simulation results on a speed controller of induction motor are presented to show the effectiveness of the proposed gain tuner. And this controller is better than the fixed gains one in terms of robustness, even under great variations of operating conditions and load disturbance.

• 제어로봇시스템학회논문지
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• 제19권9호
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• pp.839-845
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• 2013

A CSTR (Continuous Stirred Tank Reactor) is a highly nonlinear process with varying parameters during operation. Therefore, tuning of the controller and determining the transition policy of controller parameters are required to guarantee the best performance of the CSTR for overall operating regions. In this paper, a methodology employing the 2DOF (Two-Degree-of-Freedom) PID controller, the anti-windup technique and a fuzzy gain scheduler is presented for the temperature control of the CSTR. First, both a local model and an EA (Evolutionary Algorithm) are used to tune the optimal controller parameters at each operating region by minimizing the IAE (Integral of Absolute Error). Then, a set of controller parameters are expressed as functions of the gain scheduling variable. Those functions are implemented using a set of "if-then" fuzzy rules, which is of Sugeno's form. Simulation works for reference tracking, disturbance rejecting and noise rejecting performances show the feasibility of using the proposed method.

• 조명전기설비학회논문지
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• 제23권7호
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• pp.29-40
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• 2009

This paper proposes a modeling and controller design approach for a hybrid wind power generation system that considers a fixed wind-turbine and a dump load. Since operating conditions are kept changing, it is challenge to design a control for reliable operation of the overall system To consider variable operating conditions, Takagi-Sugeno (TS) fuzzy model is taken into account to represent time-varying system by expressing the local dynamics of a nonlinear system through sub-systems, partitioned by linguistic rules. Also, each fuzzy model has uncertainty. Thus, in this paper, a modem nonlinear control design technique, the sliding mode nonlinear control design, is utilized for robust control mechanism In the simulation study, the proposed controller is compared with a proportional-integral (PI) controller. Simulation results show that the proposed controller is more effective against disturbances caused by wind speed and load variation than the PI controller, and thus it contributes to a better quality wind-hybrid power generation system.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제4권2호
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• pp.187-192
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• 2004

In this paper, we proposed the method to design fuzzy controller using the experience of the operating expert and experimental numeric data for the robust control about the noise and disturbance instead of the traditional PID controller for the main steam temperature control of the thermal power plant. The temperature of main steam temperature process has to be controlled uniformly for the stable electric power output. The process has the problem of the hunting for the cases of various disturbances. In that case, the manual action of the operator happened to be introduced in some cases. We adopted the TSK (Takagi-Sugeno-Kang) model as the fuzzy controller and designed the fuzzy rules using the informations extracted directly from the real plant and various operating condition to solve the above problems and to apply practically. We implemented the real fuzzy controller as the Function Block module in the DCS(Distributed Control System) and evaluated the feasibility through the experimental results of the simulation.

• 한국기록관리학회지
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• 제9권1호
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• pp.51-75
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• 2009

공공기관에서 생산된 기록물이 제대로 활용하기 위해서는 기록물 공개가 우선되어야 한다. 어떤 기록물이 어떤 시점에 공개되어야 하는지를 판단하는 것은 매우 까다롭고, 무엇보다 이러한 판단에는 다양한 이해관계가 얽혀 있기 때문에 관련 규정과 운영현황을 재검토해 볼 필요가 있다. 이를 위해 본 연구에서는 기록물 활용단계별 공개제도의 특성을 토대로 현재 운영하고 있는 공개제도의 문제점을 살펴보고, 국내외 공개제도 분석을 통해 보다 전문적으로 효율적인 서비스 제공을 위한 우리나라 공개제도 운영 개선방안을 제안하였다. 특히 통합형 공개제도 운용과 분리형 공개제도 운영의 장단점 분석을 통해 우리나라에 적합한 공개제도 운영모델을 구상하는 데 초점을 두었다.