• 수산해양기술연구
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• 제46권1호
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• pp.70-81
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• 2010

A mathematical model is formulated to study the effect of wall mass on the thermal performance of four different houses of different construction. This analytical study was motivated by the experimental work of Burch et al. An analytical solution of one -dimensional, linear, partial differential equation for wall temperature profiles and room air temperatures is obtained using the Laplace transform method. Typical Meteorological Year data are processed to yield hourly average monthly values. These discrete data are then converted to a continuous, time dependent form using a Fast Fourier Transform method. This study is conducted using weather data from four different locations in the United States: Albuquerque, New mexico; Miami, Florida; Santa Maria, California; and Washington D.C. for both winter and summer conditions. A computer code is developed to calculate the wall temperature profile, room air temperature, and energy consumption loads. Three sets of results are calculated one for no auxiliary energy and two for different control mechanism -- an on-off controller and a proportional controller. Comparisons are made for the cases of two controllers. Heavy weight houses with insulation in mild weather areas (such as August in Santa Maria, California) show a high comfort level. Houses using proportional control experience a higher comfort level in comparison to houses using on-off control. The result shows that there is an effect of mass on the thermal performance of a heavily constructed house in mild weather conditions.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2003년도 추계학술대회
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• pp.233-236
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• 2003

In this Paper, the temperature control error and cooling characteristics of inverter typ coolers are evaluated to predict application validity of coolers under heating pattern and amount The temperature control error of coolers small in 15~70% range of the max. cooling ability. At less than 15% of max. cooling ability has the inverter type cooler a basic temperature control error $\pm0.5^{\circ}C$ and acts as on/off type coolers. The inverter type cooler is unsuitable for precision temperature control under the complex heating pattern. But PID control of cooler including the heating system is an alternative for the case.

• 조명전기설비학회논문지
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• 제27권2호
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• pp.7-13
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• 2013

The portion of lighting power consumption for our country is up to 20~30% of the total amount. Currently, most of the DSM(Demand side management) of lighting power is delivered in supply of high efficient lighting to customers. On the contrary, applications of lighting power to power load leveling are still rare. In this paper, the simulations for various control types of lighting power for load leveling are tried, and we obtained the cost effective and optimal control method through that. This simulation was executed in test office with fluorescent light by us based on applying 8 control types(on, off & dimming), considering customers' satisfaction, for instance, minimum intensity of illumination allowed. According to the result of this test, we found that mixed type(chessboard(on-off) plus dimming control(10%)) is most effective.

• 한국주거학회논문집
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• 제19권1호
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• pp.89-96
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• 2008

This study measured the thermal environment and residents' control behaviors of cooing according to 3 groups of household type-families with preschool children, families of middle age and families of senior. The object of this study are to fmd the difference of the actual condition of indoor thermal environment and cooling control behavior by age or household type and to develop user oriented climate control system. The results were summarized as follows. When the age of members at household is younger, the indoor mean temperature and temperature that people turned off the air conditioner became lower. These different indoor thermal environment of each group means that younger generation is familiar with cooler from their early age and these early uses of cooler made them prefer cooler condition than family of senior. Therefore, this results show that different indoor thermal environment is influenced by factors such as household type and metabolism difference and so on.

• 한국정보통신학회논문지
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• 제5권3호
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• pp.503-516
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• 2001

현재 국내의 산업 자동화 관련의 온실 환경 제어 시스템은 노동 집약적 시설에 타이머를 이용하여 각 장치를 제어하는 on/off식 제어반으로 구성되어 있다. 그러나 이러한 시스템은 야간이나 원격지에 있을 경우에는 온실의 상태 파악이 어렵다. 따라서, 본 논문에서는 기존의 on/off식 제어 방식을 액정 패널로 수동 제어를 하고, 컴퓨터로 수통 및 자동 제어 상황을 모니터링할 수 있는 시스템을 개발하였다. 또한, 재배 작물에 대한 관련 정보를 DB로 구축하여 사용자에게 정보 획득의 편의성을 제공하도록 한다.

• 정보보호학회논문지
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• 제13권1호
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• pp.147-155
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• 2003

인터넷 인프라의 보급과 이용인구의 급속한 증가는 off-line을 통해서 물리적으로 제공받아 이용하던 다양한 정보와 자료, 그리고 디지탈 컨텐츠를 인터넷을 통해서 쉽고 빠르게 이용할 수 있는 서비스의 기반이 되고 있다. 그러나 인터넷 서비스를 통해서 제공되는 다양한 컨텐츠의 저작권 보호와 불법 복제 등과 같은 문제는 해당 사업의 발전을 저해하는 위험요소가 되고 있다. 이와 같은 문제를 해결하기 위한 방안으로 컨텐츠를 이용할 수 있는 정당한 자격을 소유한 사용자만이 해당 컨텐츠를 정상적으로 이용할 수 있도록 하는 접근제어(Access Control, AC) 기술이 연구되고 있다. 위성 방송에서 사용되고 있는 제한수신 시스템(Conditional Access System, CAS)과 인터넷 컨텐츠 서비스에 사용되고 있는 디지탈 저작권 관리 시스템(Distal Right Management System DRMS)은 현재 상용화되어 있는 AC의 대표적인 모델이라 할 수 있다. CAS와 DRMS는 지불 구조에 기반을 둔 형태(Payment Based Type, PBT)의 AC 기술이라 할 수 있다. 본 논문에서는 ［5］에서 제시된 지불 구조에 독립적인 형태(Payment Free Type, PFT)의 AC를 위한 보안 체계를 살펴보고, 각각의 특징을 간략하게 정리한다. 또한 효과적인 운영을 위한 PRT 기반의 새로운 AC 구조를 제시한다.

• 한국추진공학회지
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• 제19권2호
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• pp.17-28
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• 2015

본 논문에서는 ON/OFF 작동과 같이 단순화된 구동 메커니즘을 가지면서도 구동 명령 한계가 있는 시스템의 구동 위치 제어 기법 설계를 수행하였다. 가장 먼저 구동기 시험데이터를 이용하여 고려되는 구동기의 PWM 명령을 입력으로 하는 비선형/선형 구동 동역학 모델링을 수행 하였다. 선형화된 모델을 이용하여 목표로 하는 제어 성능 요구조건을 만족시키기 위한 고전적인 PI 제어기법을 설계하였으며, PWM 제어명령 한계에 따른 제어 성능 감소를 해소하기 위한 제어 알고리즘을 제안하여 유효 제어 범위 내에서 설계된 제어 성능이 구현되도록 하였다. 최종적으로 제어 시뮬레이션을 통해 설계 방법을 검증하고 해당 제어기법 적용에 따른 성능 개선 정도를 평가하였다.

• 한국표면공학회지
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• 제39권4호
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• pp.153-159
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• 2006

Nanodiamond films were deposited on Si substrate by introducing a time dependent on/off modulation of $CH_4\;and\;O_2$ flows in a vertical-type microwave plasma enhanced chemical vapor deposition system. Surface morphology and diamond quality of the film were investigated as a function of the on/off modulation time interval. The diamond nucleation density on the substrate was enhanced under low temperature and low pressure condition. In addition, the diamond nucleation density was enhanced by increasing the on/off modulation time interval. Enhanced diamond quality was noticeable under the condition of a longer on/off modulation time interval. It was suggested that the nanodiamond nuclei formed the cluster formation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1991년도 하계학술대회 논문집
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• pp.443-446
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• 1991

In the conventional current control methods for the current-type reactive power compensators, it is usual to compare the reactive reference current signal with the triangular wave and hence to generate the ON-OFF signals for the semiconductor reactive power compensator. To improve the response as well as the control capability, the delta modulated current control technique is proposed in this paper and studied theoretically.

• 설비공학논문집
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• 제25권3호
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• pp.137-142
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• 2013

A small air-conditioner or chiller for a constant temperature bath normally uses a constant speed compressor. The constant speed compressor is relatively inexpensive, but it uses on/off control for capacity modulation. The on/off control has several disadvantages, specifically energy loss and large temperature fluctuation. Continuous operation with a bypass system can be an alternative to on/off control, for capacity modulation. In this study, a heat pump system having a hot-gas bypass and a liquid bypass was adopted. The performance of the bypass-type heat pump was measured, by varying the bypass valve opening. The differences of the COP between the hot-gas bypass and the liquid bypass, in the cooling and heating operations, were within 2% and 1%, respectively. The liquid bypass showed a wider range of capacity control in the cooling operation but the hot-gas bypass showed a wider range of capacity control in the heating operation.