• 한국통신학회논문지
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• 제34권8A호
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• pp.600-609
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• 2009

기존의 IEEE 802.11 DCF(Distributed Coordination Function)와 같은 전통적인 CSMA(carrier sense multiple access) 프로토콜은 네트워크 규모가 커짐에 따라서 성능의 급격한 감쇠와 전송 지연 증가를 초래한다. 이러한 문제를 효과적으로 해결하기 위하여 본 논문에서는 무선 센서 네트워크에 적합한 MAC(medium access control) 프로토콜을 제안한다. 기존의 DCF 프로토콜은 데이터 전송을 위한 슬롯(slot)을 선택할 때 패킷 충돌로 인한 재전송이 반복될 때 마다 크기가 커지는 경쟁 윈도우(contention window) 내에서 일반 확률 분포(uniform probability distribution)를 이용한 랜덤(random) 선택 기법을 사용하지만 제안한 프로토콜에서는 전송 지연을 최대한 감소시키기 위하여 경쟁 윈도우의 크기를 고정시키고, 전송 슬롯을 보다 효율적으로 선택하도록 비 균등(non-uniform)확률 분포를 사용하여 전송 슬롯을 랜덤하게 선정한다. 시뮬레이션을 통하여 제안한 프로토콜이 802.11 MAC 표준에 비하여 전송 지연이 감소함을 보여 전송 지연에 민감한 실시간 무선 센서 네트워크의 최적 지연 한계점(best latency bound)을 충족시키는 프로토콜임을 입증한다.

• 한국멀티미디어학회논문지
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• 제24권1호
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• pp.30-39
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• 2021

Research in the field of health lighting has continued to advance to reproduce the color temperature of natural light which periodically changes. However, most of this research could only reproduce a uniform circadian color temperature of natural light, therefore failing to realize the characteristics of the circadian cycle of color temperature difference by latitude and longitude. To reproduce the color temperature of natural light on which the characteristics of a region are reflected, the collection technology of real-time characteristics of natural light is needed. If the color temperatures which are not within a periodical pattern due to climate changes, etc., are measured, it will be difficult to judge the occurrence (presence) of the anomalies and to reproduce the circadian cycle of the color temperature of natural light. Therefore, this study proposes an algorithm for judging the anomalies in real time based on the sliding window to reproduce the color temperature of natural light. First, the natural light characteristics DB collected through the on-site measurement were analyzed, the differential values at a one-minute interval were calculated and examined, and then representative color temperature circadian patterns by solar terms were drawn. The anomalies were then detected by the application of the sliding window that calculated the deviation of the color temperature for the measured color temperature data set, which was collected through RGB sensors, while moving along the time sequence. In addition, the presence of anomalies was verified through the comparison study between the detection results and the representative circadian cycle of the color temperature by solar term. The judgment method for the anomalies from the measured color temperature of natural light was proposed for the first time, confirming that the proposed method was capable of detecting the anomalies with an average accuracy of 94.6%.

• 대한인간공학회지
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• 제25권2호
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• pp.23-32
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• 2006

Window buttons located on a task bar provide information about windows that have been open as well as active. When the number of buttons on the task bar increases, the button size gets smaller and as a result, it is more difficult to identify. This study proposes new alternatives of presenting window buttons to search for a target button efficiently. An experiment was conducted to evaluate the usability of the new. Factors manipulated in the experiment include 'button arrangement methods' and 'order of buttons'. The 'button arrangement methods' factor is composed of three levels, 'one line', 'changeable line', and 'grouping buttons'. The 'order of buttons' factor is composed of three levels, 'fixed order', 'click-right', and 'order control by user'. The results showed that the main effects were significant in search time. In subjective satisfaction, the interaction effect was also significant. The results could be applied to the design of small screens such as PDA or cellular phones.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2018년도 추계 학술논문 발표대회
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• pp.138-139
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• 2018

The purpose of this study is to analyze the work of the existing manpower dependent cleaning method by investigating the window cleaning site. In this study, detailed work contents were confirmed by on-site investigation and interview with experts, and the relationship, procedure, repetition work, and time required for each work were analyzed. The future analysis results will be used as a basic data for comparative analysis of productivity and economical efficiency with the window cleaning device to be developed.

• 한국통신학회논문지
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• 제22권3호
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• pp.593-603
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• 1997

Connection admission decision in ATM networks requires decision made in real time using fast algorithm. It is difficult to construct a model of the multiplexed traffic and thus, approximation of the traffic load is necessary. In this paper, we propose a measurement-based dynamic CAC(Connection admission Control) in ATM(Asynchronous Transfer Mode) networks, which observes current traffic by the moving window and set the window size to the value which is computed from the measured cell loss amount. It is based on the measurements of the traffic load over an admission period that is load enough to reflect the current traffic behavior instead of analytic modeling. And, the dynamic reallocation of bandwidth for each class leads to effective bandwidth utilization. The performance of proposed method is analyzed through computer simulation. The performance of proposed method is analyzed by using SIMAN simulation package and FORTRAN language. As can be seen in the simulation result, cell loss performance and bandwidth utilization have been increased.

• 한국화재소방학회논문지
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• 제27권3호
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• pp.8-13
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• 2013

건물 내부에서 화재 발생 시 외벽에 설치된 유리벽이나 창이 파손되며 이를 통해 화염이 밖으로 노출되면 화재는 외벽을 타고 수직상승하며 급격히 확대될 수 있다. 이를 막기 위한 효과적인 방법으로는 현재 내화유리를 사용하거나 또는 유리가 화염에 견딜 수 있도록 냉각수 등으로 방호해주는 윈도우 스프링클러 방식이 있다. 본 연구에서는 실내 유리창 상단에 설치되어 화재 시 열기류에 의해 감열체가 개방되면 유리에 냉각수를 방수하며 화염으로부터 유리를 방호해주는 윈도우 헤드를 개발하여 이의 내화성능을 평가하고자 하였으며 이를 위해 실규모 수직가열로를 이용해 유리창 시험체를 표준 온도-시간곡선에 따라 가열하여 윈도우 헤드의 내화시험을 실시하였다. 실험결과 1개의 윈도우 헤드로 최대 너비 2,400 mm의 유리창을 2시간 동안 방호하는데 성공하였으며 이 때 유리창 이면의 최고온도는 국소적으로 $126^{\circ}C$까지 상승하였으나 평균 $100^{\circ}C$를 유지하며 안정된 내화성능을 나타내었다.

• 산업공학
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• 제4권1호
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• pp.63-69
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• 1991

In this paper, the Go-Back-N ARQ protocol with decoding in communication network is considered. The time delay and throughput are respectively analyzed as a function of window size and decoding time out. Packets arrive continuously at the decoder, and are stored in a buffer if the decoder is busy upon its arrival. The decoder devotes no more than a time-out period of predetermined length to the decoding of any single packet. If packet decoding is completed within that period, the packet leaves the system. Otherwise, it is retransimitted and its decoding starts anew. The time delay and throughput are obtained using recursive formula and difference equation. An appropriate time out and window size that satisfies the grade of service can be determined.

• 한국통신학회논문지
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• 제22권11호
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• pp.2401-2408
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• 1997

The measured pulse shapes provided in the given data package demonstrated pulse distortions due to laser speckle. the distorted pulse shapes were carefully analyzed, modeled, and then applied to the DTTL(Digital-data Transition Tracking Loop)[1] bit synchronizer simulator to measure the mean time delay and its delay variation performance. The result showed that the maximum mean time delay variation with the modeled data was 12.5% when window size equals 1. All the data given were located within this modeled boundary and the maximum eman time delay variation was 7% in this case. The mean time delay variation was known to be smaller by reducing the window size [2][5][6]. The mitigated delay variation was 2.5% in the modeled case and 1.4% in the data set given when the windown size equals 0.1. With the digital DTTL insteal of analog DTTL, similar results was obtained.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1998년도 추계학술대회
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• pp.185-186
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• 1998

The discrete Wigner-distribution(DWD) was implemented for the time-frequency analysis of heart rate variability signals. The smoothed cross-DWD was used to estimate time-varying power spectrum. Spurious cross-terms were suppressed using a smoothing data window and a Gauss frequency window. The DWD is very easy to implement using the FFT algorithm. Experiment show that the DWD follows well the instantaneous changes of spectral content of heart rate variability signals, which characterize the dynamics of autonomic nervous system response.

• 산업경영시스템학회지
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• 제21권45호
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• pp.365-374
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• 1998

Control Chart is a powerful tool to detect that process is in control or out of control. CIM can have real effect when CIM involve automated quality control. A neural network approach is used for unnatural pattern detecting of control chart. The previous moving window method uses all unnatural pattern that is detected as moving time window. Therefore, It trains a large number of unnatural pattern and takes training time long. In this paper, the proposed method tests a small number of training unnatural pattern which modifies test data without repeating time. We shows that the proposed method has differences In training time and identification rate on the previous moving windows method. As results, we reduced training time and obtain the same identification rate.