• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.6 no.2
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• pp.88-94
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• 2013

In this paper, an efficient signal interference control technique to improve the convergence speed of LMS algorithm is introduced. The convergence characteristics of the proposed algorithm,whose coefficients are multiply adapted in a symbol time period by recycling the received data,are analyzed to prove theoretically the improvement of convergence speed. According as thestep-size parameter ${\mu}$ is increased, the rate of convergence of the algorithm is controlled. Increasing the eigenvalue spread has the effect of controlling down the rate of convergence of the adaptive equalizer and also increasing the steady-state value of the average squared error and also demonstrate the superiority of signal interference control to the filter algorithm increasing convergence speed by (B+1) times due to the data-recycling LMS technique.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.9A
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• pp.1329-1338
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• 1999

In this paper, an efficient signal interference control technique to improve the convergence speed of LMS algorithm is introduced. The convergence characteristics of the proposed algorithm, whose coefficients are multiply adapted in a symbol time period by recycling the received data, are analyzed to prove theoretically the improvement of convergence speed. According as the step-size parameter $\mu$ is increased, the rate of convergence of the algorithm is controlled. Also, a increase in the step-size parameter $\mu$ has the effect of reducing the variation in the experimentally computed learning curve. Increasing the eigenvalue spread has the effect of controlling down the rate of convergence of the adaptive equalizer and also increasing the steady-state value of the mean squared error and also demonstrate the superiority of signal interference control to the filter algorithm increasing convergence speed by (B+1) times due to the data-recycling LMS technique.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.4
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• pp.787-795
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• 1998

In this paper, we have improved the speed of gradient operation, which needs to calculate Optical Flow for estimating a moving object, and proposed a method which estimate the contour of a moving object by the logical operationg of Optical Flow and edge in noisy images. The proposed method, which recognize to a moving ogject and traking a moving object, using logical operation of Optical Flow and edge in low-level has a advantage that is simpler than the known method for moving objects estimation. In addition, we have simulated several images using method I and method II on improved Gradient operation speed. When we have compared the average value of total operation time, method I is improved with 12% of operation speed compared with the known method, method II is improved with 38% operation speed.

• Journal of the Korean Magnetics Society
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• v.22 no.4
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• pp.136-141
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• 2012

In the this research, two simultaneous peaks of radial artery pulse wave and ECG pulse wave measured by using clip-type pulsimeter and ECG were investigated in order to analyze pulse wave velocity. The measured value of a pulse wave velocity is about 5~7 m/s, it is proved one new method to measure an exact value of pulse wave velocity more than the typical biomedical signal monitoring system. This result implies that data measured by the oriental medical diagnosis apparatus as pulsimeter is clinically used in future.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.1841-1844
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• 2009

일반 하천에서의 유량측정 방법은 하천 조건에 따라 다르다. 전통적인 방법으로는 구조물에 의한 방법, 유속계 측정에 의한 유속-면적법, 부자에 의한 방법, 그리고 희석법 등이 있다. 그러나 이러한 방법들은 측정 위험성을 가지고 있다. 홍수시 발생되는 고유속과 심한 난류, 거대한 부유물질들은 하천 접근에 어려움을 가져오고, 측정 기기의 파손 위험성뿐만 아니라 인명피해까지 발생시킬 가능성이 있다. 최근 기존 방법들의 문제점을 해결하기 위하여 음파, 초음파, 레이더 등을 이용한 유량 측정 방법과 장비들이 개발되었다. 본 연구에서 사용한 레이더 유속계는 하천의 표면유속을 측정하는 비접촉식 센서로 홍수기 전 미리 유속 측정 단면 측량을 실시한다면 홍수시에도 비교적 신속하고 안전하게 유속을 측정할 수 있다. 따라서 본 연구에서는 레이더 유속계를 충청북도 괴산군 달천에 위치한 수전교에 설치하여 괴산댐 방류량 및 동시유량 측정 성과와 비교하였다. 2007년 7월부터 2008년 8월까지 $36m^3/s\;\sim\;821m^3/s$의 사상에서 총 10회 측정한 결과, 레이더 유속계를 사용하여 측정한 유량의 상대오차는 댐방류량 대비 -3.3% $\sim$ 27.5%로 나타나 평균11.8%의 상대오차를 보였다. 레이더 유속계 측정과 동시에 실시한 유속-면적법 측정, ADCP법 측정의 상대오차는 각각 평균 5.7%, 6.5%로 나타난 것과 비교한다면 다소 높은 오차를 보였다. 그러나 측정 시간의 경우 수위에 따라 다소 차이는 있지만 레이더 유속계를 이용하면 30분 정도의 시간이 소요되었으며, 유속면적법은 1시간 이상, ADCP법은 40분의 시간이 소요되었다. 이와 같이 레이더 유속계는 다른 방법에 비해 정확성은 다소 떨어지지만 측정 속도와 안정성 면에서는 우수하다고 판단된다. 문제점으로 지적되는 정확도 측면의 경우 레이더 유속계로 측정되는 표면유 속과 평균 유속 사이의 보정계수 문제를 보완한다면 보다 정확한 측정이 가능할 것으로 판단된다.

• Journal of Digital Convergence
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• v.13 no.9
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• pp.235-242
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• 2015

Social network technology has been increasing interest in the big data service and development. However, the data stored in the distributed server and not on the central server technology is easy enough to find and extract. In this paper, we propose a big data management techniques to minimize the processing time of information you want from the content server and the management server that provides big data services. The proposed method is to link the in-group data, classified data and groups according to the type, feature, characteristic of big data and the attribute information applied to a hash chain. Further, the data generated to extract the stored data in the distributed server to record time for improving the data index information processing speed of the data classification of the multi-attribute information imparted to the data. As experimental result, The average seek time of the data through the number of cluster groups was increased an average of 14.6% and the data processing time through the number of keywords was reduced an average of 13%.

• 대한공업교육학회지
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• v.33 no.2
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• pp.287-299
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• 2008

HTTP is one of the most widely used protocols of the WWW. Currently it uses TCP as the transport layer protocol to provide reliability. The HTTP uses separate TCP connection for each file request and adds unnecessary head-of-line blocking overhead for the file retrieval. The web application is short sized and affected by the increased handover latency of TCP in wireless environment. SCTP has attractive features such as multi-streaming and multi-homing. SCTP's multi-streaming and multi-homing avoid head-of-line blocking problem of TCP and reduce handover latency of TCP in wired and wireless environment. Mean response time is the important measure in most web application. In this paper, we present the comparison of mean response time between HTTP over SCTP with that of HTTP over TCP in wired and wireless environments using NS-2 simulator. We measured mean response time for varying packet loss rate, bandwidth, RTT, and the number of web objects in wired environment and mean response time and packet loss rate for varying moving speed and region size in wireless environment. Our experimental result shows that SCTP reduces the mean response time of TCP based web traffic.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.19 no.4
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• pp.45-54
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• 2020

This study investigated basic data on walking characteristics, including walking speed and cognitive-response for the elderly, and based on these, the time of walking signal was calculated. The on-site survey examined the actual pedestrian crossing speed using a stopwatch, and the age was divided into groups of ordinary people and the elderly. Analysis of the data showed that the average walking speed for the general public was 1.29 m/s, while the average walking speed for the elderly was 1.13 m/s, higher than that of the general public. In addition, the lower speed of the 15th percentile was analyzed to 1.01 m/s for the general population and 0.85 m/s for the elderly, showing a lower walking speed than the standard for the general area and 0.8 m/s for the protected area. However, for senior citizens who use walking sticks or wheelchairs, the speed of the lower 15th-percentile is 0.73 m/s, which is lower than the current standard of protected areas, according to the analysis.

• Proceedings of the Korea Multimedia Society Conference
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• 2002.05c
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• pp.518-523
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• 2002

우리는 생활 속에서의 원활한 의사소통을 위해 수 많은 관계와의 좋은 인터페이스를 여러 각도로 요구하며 살고 있다. 본 논문에서는 효율적인 사용자 중심의 인터페이스를 설계하기 위하여 문맥조사를 인터페이스 디자인 초기단계에 적용하는 프로토타입 제작기법을 고안하였다. 그 적용사례로 ATM(현금지급기)를 시뮬레이션 하여 분석한 결과, 기존의 시스템보다 개별 사용자의 현금지급기 서비스 처리 수행속도가 평균 40초 이상 단축되었다. 사용자 이용 시간의 단축은 비용절감과 만족도의 향상을 의미한다.

• Journal of the Korean Society for Railway
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• v.16 no.5
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• pp.402-409
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• 2013

In metropolitan railway systems, the average commuting time keeps increasing as the scheduled speed increases, and this leads to a decline of rail service usage and competitiveness. Therefore, effective express operation for urban trains is required to improve the scheduled speed. In this study, based on the obtainable time shortening efficiency and economic viability, several express operations are suggested for urban railways and these suggestions are compared by considering high performance trains with acceleration/deceleration and maximum speed improvement. As a result, the optimum express system, which can minimize the cost for sidetrack construction, is suggested.