• Journal of information and communication convergence engineering
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• 제6권3호
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• pp.343-347
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• 2008

Wakeup schemes that turn off sensors' radio when communication is not necessary have great potential in energy saving. At the start of each beacon interval in the IEEE 802.11 power saving mode specified for DCF, each node periodically wakes up for duration called the ATIM Window. However, in the power saving mechanism specified in IEEE 802.11, all nodes use the same ATIM window size. Since the ATIM window size critically affects throughput and energy consumption, a fixed ATIM window does not perform well in all situations. This paper proposes an adaptive mechanism to dynamically choose an ATIM window size according to network condition. Simulation results show that the proposed scheme outperforms the IEEE 802.11 power saving mechanism in terms of the amount of power consumed and the packet delivery ratio.

• 동력기계공학회지
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• 제14권5호
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• pp.63-70
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• 2010

Recently the power window system is widely used in automobiles to increase convenience of passengers and drivers. However some accidents or injuries have been caused by malfunction or misusage of the system. Therefore safety regulations of the system to cope up with these accidents have been strengthened gradually in many countries. Especially in America, since 2005, all vehicles which had power window system should be contented with FMVSS 118-S5 regulations. We suggest very low-cost anti-pinch window control system satisfying the regulation in this paper. Hall sensors are used and installed around a motor rotor with ring magnet to detect motor speed for anti-pinch. The optimum number of hall sensor and location angel of them are mainly investigated to get sufficient speed resolution for anti-pinch. Through some experiments, the validity of the suggested system was verified to satisfy the regulation.

• 한국융합학회논문지
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• 제3권4호
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• pp.29-34
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• 2012

자동차는 2만 여개가 넘는 부품들로 구성되어 있다. 또한, 새시와 함께 자동차 내부에는 조향장치, 파워장치, 도어 록 장치 등 많은 전기 전자 및 센서들이 부가되어 수송 외 운전자가 주행 중 운전을 용이하게 수행할 수 있는 여러 가지 장치들이 별도로 차체내부 혹은 외부에 부착되어 있다. 그 가운데 자동차의 도어 유리 부위는 제작 초기에는 운전자가 직접 휠을 회전시켜 유리문을 상하로 개폐하였으나 최근 들어 모터, 센서, 스위치 류 등의 발달로 버튼하나로 문을 상하로 개폐시키는 방법을 사용하게 되었다. 유리문을 상하로 개폐시키는 조립부위를 자동차에서는 power window motor assembly라고 이를 개발하는 것이 본 연구의 목적이다. 현재는 anti-pinch type power window motor에 ECU(Electronic Control Unit) system이 국내에서 개발되지 못하고 있다. 뿐만 아니라, 이 연구에서는 CAE 해석과 개발을 통해 anti-pinch power motor gear housing 및 cylindrical gear를 국산화 개발하고 ECU 일체형 적용을 함으로 인해 조립공정의 단순화 및 원가절감에 기여하고자 한다.

• 동력기계공학회지
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• 제9권2호
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• pp.73-80
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• 2005

Both theoretical and experimental investigations were conducted to analyze defrosting behavior of a window heater operating in the low outdoor temperature($-20^{\circ}C$). To achieve this purpose, first a warm-chamber experiment($23^{\circ}C$) was performed to measure inner and outer surface temperature of the rear window(heated by the electric heater supplying 195 W) as functions of both time and position. Secondly, a cold chamber experiment was made to continuously record defrosting process of the frosted window. From the comparisons of the two experimental results, it was found that there was a similarity between the spatial distributions of both temperature and remaining frost. Thus, the temperature data from the warm-chamber experiments can be utilized to predict an expected zone covered with remaining frosts, and this approach can also be adopted in the inspection process in order to economically guarantee optimized performance of the window heater. Finally, an analytical model based on one-dimensional, steady-state heat transfer theories was proposed and successfully predicted the outer surface temperature of the rear window surrounded by cold air($-20^{\circ}C$) for the given operating conditions(heater power, inside and outside heat transfer coefficients, and surrounding air temperature, etc.).

• ETRI Journal
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• 제31권3호
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• pp.292-297
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• 2009

The power spectral density of a signal can be estimated most accurately by using a window with a narrow bandwidth and large sidelobe attenuation. Conventional windows generally control these characteristics by only one parameter, so there is a trade-off problem: if the bandwidth is reduced, the sidelobe attenuation is also reduced. To overcome this problem, we propose using a Butterworth window with two control parameters for power spectral density estimation and analyze its characteristics. Simulation results demonstrate that the sidelobe attenuation and the 3 dB bandwidth can be controlled independently. Thus, the trade-off problem between resolution and spectral leakage in the estimated power spectral density can be overcome.

• 대한전자공학회논문지SD
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• 제45권11호
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• pp.56-62
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• 2008

현대 마이크로프로세서는 적정수준의 전력소모에 고성능의 애플리케이션성능을 요구한다. 전력소모와 성능향상의 상호보정 측면에서 볼때, 명령어 윈도우(Instruction window)는 특별히 중요한 구성요소이다. 이는 명령어 윈도우의 크기를 확장하면 성능향상을 가능하도록 하지만, 기존의 명령어 구조를 그대로 이용하여 크기만 늘리는 것은 전력소모와 복잡도 측면에서 불리하기 때문이다. 본 연구에서는 전력소모를 감소하기 위해서 직접 검색 테이블(Direct table lookup :DTL)을 사용하여 명령어 윈도우에서 발생하는 연관 검색을 최소화한다. 이를 위해 비트 벡터(bit-vector) 기반의 태그 변환 기법을 제안하여 데이터 종속성 및 자원 충돌 현상을 효과적으로 해결한다. 본 논문에서는 SPEC2000 벤치마크를 활용하여 성능평가를 수행하여 제안된 기법이 기존 방법 대비 24.45%의 전력소모 개선 효과를 나타냄을 확인하였다.

• 설비공학논문집
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• 제12권1호
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• pp.40-49
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• 2000

The flow and heat transfer characteristics of the exhaust airflow window system were studied numerically by a finite volume method. Attention was paid to see the decrease in indoor cooling load. The exhaust air flow rate, solar energy power and aspect ratio of window were considered as main variables. From the result of the comparison between the exhaust airflow window and the enclosed window, the indoor heat gain was reduced remarkably by 76%. It is also suggested that in the design of the exhaust airflow window optimum values of aspect ratio, H/W and exhaust air flow rate, Re were about 0.05 and 600, respectively.

• 토지주택연구
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• 제11권1호
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• pp.87-94
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• 2020

To implement the planning of zero-energy buildings, their energy performance must be improved, and renewable energy applications must also be included. To accelerate the use of renewable energies in such buildings, BIPVs should be actively used in windows and on roofs. Window-type BIPVs are being developed in various forms depending on the size, composition, area ratio of the window, specification of glass, and so on. To analyze the applicability of various solar cells as window-type BIPVs, in this study, we evaluated their applicability, at the current development level, by analyzing the indoor illuminance, heat gain and heat loss; the cooling, heating, and lighting energy levels; and the generation performance of the various solar cells. To enhance the future applicability of window type BIPV, we analyze the overall energy performance of the building, according to changes in visible light transmittance and generation efficiency. The main research results are as follows. The area ratios above the standard illuminance, based on the window type and according to the VLT, were in order of low-e glazing, a-Si window, DSSC window, and c-Si window. The heat gain of the semi-transparent solar cell winodw was remarkably low. The energy consumption of buildings was highest in the order of c-Si window, DSSC window, a-Si window, and clear low-e window. However, in the case of including the power generation performance of the solar cell, the energy consumption was found to be high in order of DSSC window, c-Si window, a-Si window, and clear low-e window. In the future, if a window-type BIPV is developed, we believe that improvement in power generation performance and improvement in visible light transmittance will be needed.

• 전기학회논문지
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• 제59권12호
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• pp.2298-2305
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• 2010

The paper presents the Model Based Design(MBD) method which design and verify control algorithm for safety power window. Safety power window are required to work together with the anti-pinch function and have to meet FMVSS118 S5 requirements and equivalent ECC requirements. To meet the requirements, this paper presents the establishment of SILS and RCP environments. The design process can reduce time and support more performance-assured design. As a result of study, it met the regulations and achieved reaction force that close to common products.

• 정보처리학회논문지C
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• 제14C권6호
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• pp.475-480
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• 2007

최근 무선 네트워킹 장치들이 등장 하면서 제한된 배터리에 의존하는 무선 호스트들의 전력 절감은 중요한 이슈 가 되었다. 특히 Ad-Hoc에서 배터리는 제한된 에너지를 제공하기 때문에 무선 호스트에 의해서 소모되어지는 에너지의 양을 감소시키기 위한 기술은 대단히 중요하다. 특히 MAC 과 라우팅 에서 전력 절감을 이루기 위한 논문들이 기존에 발표 되었다. 이 논문에서는 IEEE 802.11 표준의 DCF(Distributed Coordination Function)에서의 전력 절감 메카니즘을 향상 시킨 논문 이다. DCF를 위한 IEEE 802.11 전력 절감 메카니즘에서는 비콘 간격 이라는 시간으로 나누어지며 또한 이러한 각각의 비콘 간격이 시작될 때 각각의 노드들은 ATIM 창 동안 깨어 있어야 한다. 물론 모든 노드는 같은 시간에 깨어 있기 위해서는 동기화 되는 것이 필요하다. ATIM 창 동안 노드들은 비콘 기간 동안 깨어 있는 상태로 있을 것인지를 결정하기 위해서 control packet을 교환 한다. 이러한 ATIM 창 크기는 각각의 노드들의 전력 절감에 상당한 영향을 미친다. 따라서 이 논문은 ATIM 창 크기를 동적으로 증감시켜서 보다 에너지 효율을 발휘 하고자 하는 논문이다.