• International Journal of Air-Conditioning and Refrigeration
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• 제17권1호
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• pp.1-6
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• 2009

The optimum design of back pressure chamber is one of the most important factors in designing scroll compressors because it has a great influence on the efficiency and other design parameters. The design process can be divided into 2 parts. One is obtaining the optimum pressure of the chamber and keeping it in constant value. The other is finding out the minimum inflow rate of medium with which back pressure chamber is filled. In this study we are focused on the first step. At first we added a simple structure that can change back pressure without reassembling compressor. It makes possible to obtaining optimum back pressure. Then we designed an equipment that the back pressure control valve assembly could be independently tested with. Spring was redesigned to decrease stiffness variation. Also sealing mechanism of back pressure control valve was improved to more effective way. As a result, it was verified that in a real mode test back pressure variation could be retained in 2.3% with discharge pressure and operating frequency varied. In addition the integrated structure of back pressure control valve is expected to contribute to effective manufacturing process.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2007년도 동계학술발표대회 논문집
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• pp.364-369
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• 2007

A system heat pump provides the benefits of comfort, energy conservation and easy maintenance. Recently, the system heat pump has been employed in small and medium-sized buildings. However, the performance data and control algorithm for system heat pump are limited in literature due to complicated system parameters and operating conditions. In the present study, the performance of a system heat pump with two indoor unit is measured by varying indoor loads, EEV opening, and compressor speed. In addition, the integral optimum regulator which includes MIMO control algorithm is proposed. The capacity modulation and optimum capacity for each indoor unit can be adjusted by utilizing the EEVs opening and compressor speed. The proposed scheme shows appropriate control performance at test conditions.

• 한국식품저장유통학회지
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• 제5권2호
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• pp.177-185
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• 1998

For the purpose of enhanceing soybean-sprouts quality, the optimum conditions for ozone treatment of soybean during soaking before cultivation at 18~2$0^{\circ}C$ were evaluated with ozone concentration, treatment time and treatment frequency by response surface methodology. Germination rates of cleaned soybean by ozone water in the conditions of solubilized-ozone concentrations of 0.15 to 0.35ppm, ozone-treatment frequency of 1.5 to 2.3 times and ozone-treatment time of 30 to 36min. increased 18.8 to 24.0% for the control products. And, length of hypocotyl in conditions of 0.12 to 0.33ppm, 1.7 to 2.7 times and 45 to 90min. were also increased by 69.36 to 79.40%. On the other hand, weight of roots with ozone treatment were decreased in the conditions of solubilized ozone concentrations of 0.1 to 0.2ppm and ozone-treatment time of 30 to 57min. But, ozone-treatment frequency did not affected root growth. Putrefaction rates of the control were 5 to 15%, but those of ozone-treated samples during cultivation did not show. The overall optimum conditions for above 16% germination rates, above 9% hypocotyl yields compared to the control samples and below 98% of the control root weight were solubilized-ozone concentrations of 0.25 to 0.30ppm, ozone-treatment time of 43 to 49min. and ozone-treatment frequency of one time.

• 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.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1997년도 전력전자학술대회 논문집
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• pp.182-187
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• 1997

In this paper, a instantaneous speed measurement method using a three phase sinusoidal encoder is described and it's simulations are developed. The proposed method can easily detect the AC motor speed by using that the encoder is propotion to the AC motor speed. The performance of proposed method is confirmed by computer simulation and experiment results. The high accuracy of the optimum control system, AC motor speed detection is designed and proposed.

• 전자공학회논문지B
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• 제31B권3호
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• pp.141-149
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• 1994

In this paper, we could find optimum quantum sequence(OQS) to minimize the output ripple voltage of the quantum series resonant converter(QSRC). This sequence control is so general that it is irrelevant to the voltage gain so far as it is operating in the continuous conduction mode(CCM). Further more the dynamic range of QSRC is much extended by the optimum quantum sequence control(OQSC). Througuout the time-domain analysis, the solution of steady state and the boundary condition between continuous and discontinuous mode is QSRC is obtained. This feature is verified by simulations and experiments with good agreements.

• 전기의세계
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• 제22권4호
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• pp.11-16
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• 1973

This paper presents an optimum control of the field resistance for the self-excited DC shunt generator to keep a constant terminal voltage in case of the load change or the torque variation in the system. The non-linearity of the system is linearized by applying the small signal technique and the linearized equation is solved by the maximum principle with the digital computer. The optimal control value of the field resistance for the step error of the generator output voltage is obtained and the transient voltage characteristics in the system are investigated.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2002년도 춘계학술대회 논문집
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• pp.404-410
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• 2002

In this study, we have analyzed the optimum control of wheel for coach car in maintenance process to grasp the problem relating to this coach's wheel exchanged. So, these problems brought about decrement maintenance cost. This study were deliberated to solve problems concerning maintenance process of wheel exchanged and wheel specification in rolling stock workshops of KNR. Here, we describe some results.

• 전기의세계
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• 제20권1호
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• pp.9-18
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• 1971

The characteristics of optimum control for the second order P.W.M. sampled-data system with linear plants are investigated, with the development of method for finding the cannonical represetations for the initial states, as well as the optimality of modulator output for the P.W.M. system, which contains the electro-mechanical components, by dividing the phase plane into several regions, in which the position of the system in the phase plane are converted into the pulse polarity and pulse width.

• 한국기계가공학회지
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• 제7권1호
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• pp.17-21
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• 2008

Recently developed automotive components are of lightweight nature, providing automobiles with a high fuel efficiency and performance. In response to those trends of car developments, this study proposes a structural optimization method for the lower control ann. Lightweight design of lower control am can be achieved through two approaches: design and material technology. In this research, the former includes optimization technology, and the latter the technologies for selecting aluminum as a steel-substitute material. In this research, the design of experiments(DOE) built in ANSYS WORKBENCH are utilized to determine the optimum shape of a Lower Control Arm. And optimum design is compared first model and reduced design variable model that considered sensitivity using orthogonal array.