• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 2000년도 THE THIRD INTERNATIONAL CONFERENCE ON AGRICULTURAL MACHINERY ENGINEERING. V.II
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• pp.498-505
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• 2000

Performance of a hydraulic system is influenced by its working temperature. Therefore, it is very important to make the system perform uniformly in an entire range of the working temperature. In this study a simulation of a hydraulic control system for the powershift transmission of tractors was conducted and the effect of the temperature was investigated in terms of design conditions of the system. Results of the simulation are as follows. The hydraulic control system with a spring accumulator was found to be more convenient to control the shifting time than that with a gas accumulator. By returning the oil from the clutches to the system through a path between the filter and pump, the time delay due to the pressure difference between the low and high temperatures could be reduced. Therefore, it was recommended that the hydraulic control system for the powershift transmission of tractors must be equipped with a spring accumulator and a circuit to return oil from the clutches to the system through a path between the filter and pump.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1992년도 추계학술대회 논문집
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• pp.158-160
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• 1992

To control internal temperature distribution of moulding machine is very important in molding products such as Polycabonate. Nylon and PVDF. In this experiment, we developed temperature measurement system in order to control temperature of moulding machine. It was measured by telemetering system because of rotational mechanism. Form experimental results, it was sufficient to apply to moulding machine under 250 .deg C.

• Journal of Advanced Marine Engineering and Technology
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• 제32권8호
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• pp.1303-1308
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• 2008

Keeping cooling water temperature higher within the allowable range helps marine engines to run in more efficient condition especially when the engine load is low. Temperature control of jacket cooling water in outlet side of main engine has been more widely adopted to ships these days for the purpose to reduce fuel consumption rate. But If the temperature sensor for the control loop is placed at the outlet of engine, it brings more difficulties in attaining stable and desirable properties due to dead times included in pipe length and engine itself comparing to the case where the measuring point is at the inlet side of main engine. In relation with this problem, Feed-forward control could be one of realistic solutions as it reveals good properties and requires less cost for system configuration. This study suggests a forward control system which leads to improved temperature control performances to disturbance signals which could arise from variation of engine load or weather condition. Two dead times in the modelling were described, considering pipe length between the actuator and the engine as well as the thermal process inside the engine. The results of analysis were shown by simulations to confirm responses under different conditions.

• 설비공학논문집
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• 제14권4호
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• pp.350-357
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• 2002

Optimal control algorithms for the full storage ice cooling system were developed by using a dynamic simulation program. Control algorithms for the storage charging mode were developed for the chiller outlet temperature setpoint control and the chiller capacity control. Control algorithms for the storage discharging mode were developed for the proper mode selection, the storage-only mode control, and the storage-priority chiller-shared mode control. Two different cases of the expected outdoor air temperature profile and the expected cooling load profile were used to analyze the effectiveness of these algorithms. Simulation results show the energy savings and the satisfactory controls of the ice storage system. Therefore, control algorithms developed for this study may effectively be used for the improved control of the ice storage cooling system.

• 수산해양기술연구
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• 제58권4호
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• pp.359-366
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• 2022

In this study, the load fluctuation of the main engine is considered to be a disturbance for the jacket coolant temperature control system of the low-speed two-stroke main diesel engine on the ships. A nonlinear PID temperature control system with satisfactory disturbance rejection performance was designed by rapidly transmitting the load change value to the controller for following the reference set value. The feed-forwarded load fluctuation is considered the set points of the dual loop control system to be changed. Real-coded genetic algorithms were used as an optimization tool to tune the gains for the nonlinear PID controller. ITAE was used as an evaluation function for optimization. For the evaluation function, the engine jacket coolant outlet temperature was considered. As a result of simulating the proposed cascade nonlinear PID control system, it was confirmed that the disturbance caused by the load fluctuation was eliminated with satisfactory performance and that the changed set value was followed.

• Transactions on Control, Automation and Systems Engineering
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• 제3권2호
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• pp.133-138
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• 2001

This paper describes a system that can used to recognize an unknown material regardless of the change of ambient tem-perature using temperature response curve fitting and fuzzy neural network(FNN). There are some problems to realize the recogni-tion system using temperature response. It requires too many memories to store the vast temperature response data and it has to be filtered to remove noise which occurs in experiment. And the temperature response is influenced by the change of ambient tempera-ture. So, this paper proposes a practical method using curve fitting the remove above problems of memories and nose. And FNN is propose to overcome the problem caused by the change of ambient temperature. Using the FNN which is learned by temperature responses on fixed ambient temperature and known thermal conductivity, the thermal conductivity of the material can be inferred on various ambient temperature. So the material can be recognized by the thermal conductivity.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2011년도 춘계학술발표대회 논문집
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• pp.199-203
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• 2011

With the improvement of standard of manufacturing process, oil cooling unit for manufacturing machine has been developed. A control system must be designed in order to keep oil temperature of the machine within a very restricted range and also to reduce energy consumption. In order to get the low deviation of the controlled temperature and the low efficiency, the on/off control scheme is gradually being replaced by a variable speed refrigeration system (VSRS) with an inverter driven compressor over recent decades. This paper gives the flowchart to control the compressor speed and also the electronic expansion valve (EEV) aperture in oil cooling unit refrigeration system using R22 as the refrigerant. This control scheme has already tested in experiment apparatus with room temperature condition constant at $25^{\circ}C$ and variable load condition at 4kW, 6kW, 7kW, 8kW and 10kW.

• 한국전자통신학회논문지
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• 제10권4호
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• pp.433-439
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• 2015

CCTV용 함체 내부는 일정한 습도와 온도를 유지시켜 습윤에 의한 단락방지, 온도차에 의한 결로방지, 고온방지 등의 항온항습장치가 요구되며 이를 대응한 함체에 최적화된 형태와 구조, 에너지활용 정도의 항온항습 자동제어장치개발이 필요하다. 함체내부에 있는 고가의 영상장비를 온도 변환에 따른 해저드로부터 장치보호, 단락사고를 예방할 수 있는 항온항습 제어장치가 필요하다. 이는 영상기록 및 현장상황에 신뢰성 있는 영상의 저장 및 전송을 위한 부속장치가 절대적으로 요구되는 시스템이다.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 2000년도 THE THIRD INTERNATIONAL CONFERENCE ON AGRICULTURAL MACHINERY ENGINEERING. V.III
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• pp.676-683
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• 2000

For high quality storage of agricultural products, temperature, humidity and gas conditions in a storage house should be controlled properly. But most of the low temperature storage house is depending on temperature control. This study aimed to develop an automatic control system for low temperature storage house that can control storage conditions such as temperature, humidity and $CO_2$ gas concentration. The developed system alarms the user, by telephone or beeper, when abnormal condition has occurred. The farmer can also monitor the inside condition of warehouse in his residence, by Internet. From the results of the performance test, the temperature and relative humidity in the warehouse is controlled within the range of ${\pm}0.5^{circ}C$ and ${\pm}2%$, respectively.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2006년도 하계학술발표대회 논문집
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• pp.795-800
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• 2006

A common approach to achieve better thermal comfort with hydronic radiant floor heating system is supply water temperature control. This is the control method through which supply water temperature is varied with outdoor temperature. In this study, a comprehensive, yet simple calculation method to find optimum supply water temperature is evaluated by combining heat loss from the building and heat emission from the hydronic radiant floor heating system. And then the control performance of suggested calculation method is confirmed through experiment. It is shown that indoor air temperature is stably maintained around the set point.