• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.5
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• pp.421-429
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• 2004

In Korea, the radiant heating system has been widely used as a residential heating method, which has been modernized to use hot water running into the tubes embedded in the floor structure. According to the recent improvement of living standard of residential buildings, the requirement of the thermal comfort and energy saving in heating system has been raised. Until now, the radiant floor heating system has been controlled by room thermostat installed in the living room, but for better thermal comfort, an individual room control method is adopted as an alternative. Therefore, it is necessary to evaluate the control performance between the current control method and the individual room control method. In this study, the control performance between the two systems is evaluated through the field experiment. And the control performances of room air temperature and energy performances are analyzed through the simulation using TRNSYS. Firstly, the simulations are performed in the various outdoor conditions and the flow rates and the simulation results are analyzed for the control performances. Also, to evaluate the energy performance, the simulations are performed under the operating conditions in which the set-point of the room air temperature is fixed or changed according to the schedule of occupancy, and the simulation results are analyzed between the two methods.

• Proceedings of the KAIS Fall Conference
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• 2012.05b
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• pp.704-707
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• 2012

현재 국내 농업은 고령화로 인하여 10년간 전체 농촌인구의 3분의 1이 감소하고 있으며 농업 인구의 공동화 현상이 진행되고 있다. 농촌 인구의 인력을 해결하기 위해서 농업 선진국들은 적은 인력으로 생산성을 증대하기 위해서 자동화 시스템을 도입하고 있다. 따라서 국내 농업 생산성 증대를 위해 자동화 시스템은 필수적이며 도입으로 인하여 인력 부족 현상을 해결하고 농가 소득을 필요성이 중요시되고 있다. 따라서 진정한 무인 자동화 시스템이 가능하려면 신뢰성이 보장되면서 일반 농가에서도 부담 없이 도입 할 수 있는 저가의 시스템이 필요하다. 이러한 시스템을 필요로 하는 농가에 시스템을 구축 시 들어가는 구축비용을 줄이기 위해 저가의 센서들을 네트워크로 연결하여 안정적으로 동작하는 서버 개발이 필요하며 이러한 서버를 통하여 실시간으로 손쉽게 눈으로 확인하기 위하여 스마트폰과에 연계 기술이 필요하다. 본 연구에서는 온도, 습도, Co2등의 다양한 영농 환경 정보들을 수집하고 이를 스마트폰으로 통하여 실시간으로 확인하게 할 뿐만 아니라 원격제어를 통하여 천장계폐와 LED를 손쉽게 제어 할 수 있도록 하였다. 이렇게 설계된 시스템으로 제어뿐만 아니라 수집된 데이터를 통하여 농가 환경을 분석하기 위한 정보로써 활용 될 수 있으며 유무선 공유기를 통하여 언제 어디서든 네트워크가 연결된 곳이라면 시스템에 접근이 가능 하도록 하였다.

• Journal of the Korea Computer Graphics Society
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• v.13 no.4
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• pp.1-6
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• 2007

In this paper we describe the method of controlling the animation of 3D characters according to ISO/IEC 19774 (H-Anim) specification, which has been released by Wed3D Consortium and ISO/IEC SC24 WG6. The animation structure of the H-Anim character can be defined and modified in our H-Anim editor program. Our H-Anim animator generates the character's motion automatically according to the input of motion parameters at the character's joints interactively. This paper is focused on the development of a motion generation tool for human-like characters defined by H-Anim structures.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.28 no.2
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• pp.69-74
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• 2016

Most hot water heating valves for apartments are constant-flow types, which limit the flow rate through an individual household for even distribution of heating water to other households. The constant-flow type is implemented by an on-off control. As a result, heating water is supplied intermittently and hence, indoor air temperature also fluctuates. Returning water temperature is also high, which reduces energy efficiency. To implement continuous feedback control, the indoor temperature dynamics was simulated to fit a measured temperature history by a state-of-the-art physical model. From the model, it was found that the most important disturbance is outdoor temperature and its effect on indoor temperature lasts about an hour. To cope with the slow response and the significant disturbance, a prediction control with proportional feedback is proposed. The control was found to be successful in implementing continuous heating water flow and improved indoor temperature control.

• Proceedings of the Korean Information Science Society Conference
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• 2005.07a
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• pp.298-300
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• 2005

웹데브는 HTTP1.1의 확장으로서 지역적으로 분산된 사용자들 사이에 공동 저작활동을 지원하는 표준 프로토콜이다. 웹데브의 주요 기능인 속성 관리는 저장소의 역할과 함께 자원의 추가 정보를 관리하고 활용할 수 있는 장점을 가지며, 웹데브 접근 제어 프로토콜을 이용하면 사용자에 대한 접근제어를 보다 효과적으로 설정, 관리할 수 있다. 따라서 웹데브 기반의 응용 프로그램을 개발하기 위해서는 사용자 정의 속성의 설계 및 속성의 효과적인 관리 그리고 사용자에 대한 접근 권한 설계가 매우 중요한 역할을 한다. 본 논문에서는 협업을 지원하는 팀작업장에 필요한 웹데브 사용자 정의 속성을 설계하고 설계된 속성을 효과적으로 관리하기 위한 방법 그리고 웹데브 접근 제어 프로토콜을 이용하여 사용자에 대한 접근 권한을 효과적으로 적용하는 방법을 제안한다. 웹데브를 기반으로 한 팀작업장이 개발됨으로써 협업을 위한 자료의 공유 및 교환을 보다 효율적으로 지원한다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.8
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• pp.21-29
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• 2002

In the present study, a passive control method, using a porous wall and cavity system, is applied to the shock wave/boundary layer interactions in transonic moist air flow. The two-dimensional, unsteady, compressible, Navier-Stokes equations, which are fully coupled with a droplet growth equation, are solved by the third-order MUSCL type TVD finite difference scheme. Baldwin-Lomax model is employed to close the governing equations. In order to investigate the effectiveness of the present control method, the total pressure loss of the flow and the time-dependent behaviour of shock motions are analyzed in detail. The computed results show that the present passive control method considerably reduces the total pressure losses due to the shock wave/boundary layer interaction in transonic moist air flow and suppresses the unsteady shock wave motions over the airfoil as well. It is also found that the location of the porous ventilation significantly affects the control effectiveness.

• Journal of Biomedical Engineering Research
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• v.23 no.1
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• pp.33-38
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• 2002

A Ventricular Assist Device(YAD) is used to support the injured natural heart So. when considering a control algorithm for YAD. it is important to reduce a natural heart's load to enhance its recovery condition. To reduce natural heart's load, a counterpulsation algorithm is used commonly. In this study, we developed a counterpulsation control algorithm for moving-actuator type VAD and tested its usefulness using in vitro MOCK circulatory system. To notice a natural heart's Pumping status, electrocardiogram(ECG) signal was used and as a result of test. the counterpulsation effect between YAD and a natural heart was occurred and Automatic Control Mode Transition was occurred properly.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.463-466
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• 2002

In order to examine the possibility of using a cavity as a passive device for reduction of skin friction and heat transfer, an intensive parametric study over a broad range of the cavity depth and length at different Reynolds numbers is performed for both laminar and turbulent boundary layers in the present study. Direct and large eddy simulation techniques are used for turbulent boundary layers at low and moderate Reynolds numbers, respectively. for both laminar and turbulent boundary layers over a cavity, a flow oscillation occurs due to the shear layer instability when the cavity depth and length are sufficiently large and it plays an important role in the determination of drag and heat-transfer increase or decrease. For a cavity sufficiently small to suppress the flow oscillation, both the total drag and heat transfer are reduced. Therefore, the applicability of a cavity as a passive device for reduction of drag and heat transfer is fully confirmed in the present study. Scaling based on the wall shear rate of the incoming boundary layer is also proposed and it is found to be valid in steady flow over a cavity.

• Journal of Digital Contents Society
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• v.6 no.1
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• pp.79-83
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• 2005

Our Digital Carousel enables user to share media objects through media synchronization mechanism. We implemented the Digital Carousel so that the users participated in collaborative work may refer shared media or error objects as the same view to others. This paper explains the design and implementation of the EC_DXS(Error Control in Digital Carousel System). EC_DCS is a system that is suitable for detecting sharing and recovering software error based on multimedia CSCW(Computer Supportes Cooperated Work). With error sharing system, a group cooperating users can share me. applications. From the perspective of multimedia collaborative environment, an error application becomes another interactive presentation error is shared with participant engaged in a cooperative work.

• Journal of Ocean Engineering and Technology
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• v.32 no.3
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• pp.208-212
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• 2018

In this paper, we focus on planing avoidance control for a supercavitating underwater vehicle based on the potential function method. The planing margin can be calculated using the relative position between the cavity center and vehicle center at the end of the vehicle. The planing margin was transformed into a limit variable such as the pitch angle and yaw angle limit. To prevent the vehicle attitude from exceeding the limit variable, a potential function based planing envelope protection method was proposed. The planing envelope protection system overrides commands from the tracking controller, and the vehicle attitude converges to a desired angle, in which the potential function is minimized. Numerical simulations were performed to analyze the physical feasibility and performance of the proposed method. The results showed that the proposed methods eliminated the planing, allowing the vehicle to follow tracking commands.