• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.3D
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• pp.393-400
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• 2006

This study is intended to examine the characteristics of driver in the use of guide sign in urban areas. The good and bad points about guide sign based on landmark point and guide sign based on street name are demonstrated, and driver's preference between them are studied. The questionnaires given to general persons deal with general guide signs and road maps, and are designed to see if they can find out current location on the road map with guide sign. According to the results, drivers prefer guide sign based on street name to guide sign based on landmark. And guide sign based on street name took less time to find current location than with guide sign based on landmark.

• Proceedings of the Korean Information Science Society Conference
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• 2007.10b
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• pp.285-290
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• 2007

본 논문에서 구현하고자 하는 유비쿼터스 컴퓨팅 응용에 필요한 위치 인식 시스템의 주 요소는 블루투스 프로토콜 스택(BlueZ)에서 제공하는 RSSI(Received Signal Strength Indicator) 값을 측정하는 블루투스 AP, 측정된 RSSI 값을 위치 인식 서버에 전달하기 위한 무선 AP 공유기 그리고, 받은 데이터로 위치 값을 측정하는 위치 인식 서버 및 Context Broker(고 수준의 상황 정보를 추론하는 서버 역할)로 이루어져있다. 전체적인 동작 시스템은 위치 값을 측정하고자 하는 이동 매제(마스터)를 중심으로 최대 여덟 개까지 네트워크가 가능한 블루투스 AP(슬레이브)장치로 구성된 피코넷(Piconet) 영역에서 삼각측량 필요에 적절한 세 개의 블루투스 AP를 RSSI값을 이용하여 분류 한 후 이동 매체의 위치를 측정한다. 그 결과로 나온 데이터는 피코넷 영역에서 가장 가까운 무선 AP 공유기를 거쳐서 위치 값을 측정하는 위치 인식 서버에 전달한 후, 그 결과 값으로 Context Broker에서 상황 정보를 추론해서 Community Manager에서 유비쿼터스 컴퓨팅 응용에 맞게 서비스를 구현한다. 또한, 위와 같은 시스템 내부 구조 된 데이터처리는 리눅스 운영체제 내에서 디바이스 드라이버와 사용자 프로그램으로 구현된다.

• The Journal of the Acoustical Society of Korea
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• v.35 no.4
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• pp.310-318
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• 2016

This study deals with a method to localize a noise source occuring in a marine vehicle in a 3D environment. Even when access to the noise source is limited for a marine vehicle, such as a ship or a submarine in operation, the signal received on a hydrophone located elsewhere contains Doppler effected noise by moving relatively. This study suggests noise localization algorithm in 3D based on Doppler effect by moving marine vehicle. Using a known source mounted on the vehicle, the noise source was estimated by reducing the range of Doppler center and closest point of approach via the least square method. The algorithm was verified through various simulations and it was shown that the noise could be localized in 3D based on Doppler effect by employing two fixed hydrophones located at the vehicle's exterior points and a known reference signal generator located somewhere on the vehicle.

• Korean Journal of Remote Sensing
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• v.12 no.2
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• pp.111-125
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• 1996

A forecast technique using GMS-4(Geostationary Meteorological Satellite) infrared images and its $T_{BB}$ (Brightness Temperature) data to determine the tropical cyclone center and to analyze the tropical cyclone intensity has been developed. First, the determination of typhoon center using $T_{BB}$ distribution pattern is practiced by understanding a special feature of central cloud pattern and cloud band which is analyzed with the method of pseudo coloring. Then, to forecast the intensity of tropical cyclone, a relationship between the central pressure (or maximum wind speed) of tropical cyclone and $T_{BB}$ measured by GMS near the tropical cyclone center was investigated. The results showed a correlation with a high lag relationship between central pressures and $T_{BB}$. The mean Tee in the ring of 200~300km apart from the tropical cyclone center showed the best correlation to central pressure of the tropical cyclone after 24hour. From this relationship, a regression equation to forecast the central pressure (or maximum wind speed) was derived.

• Journal of radiological science and technology
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• v.32 no.4
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• pp.453-460
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• 2009

The purpose of this study was to determine the dose distribution and image quality according to slice thickness and BC(beam collimation) in the gantry aperture. CT scans were performed with a 64-slice MDCT(Brilliance 64, Philips, Cleveland, USA) scanner. To determine the dose distribution according to BC, a ionization chamber was placed at isocenter and 5, 10, 15, 20, 25 and 30 cm positions from the isocenter in the 12, 3, 6 and 9 o'clock directions. The dose distribution for phantom scan was also measured using CT head and body dose phantom with five holes at the center of the phantom and the positions of the 12, 3, 6 and 9 o'clock directions. The image noise measurement for different BCs was performed using an AAPM CT phantom. Water-filled block of the phantom was moved by 5 cm or 10 cm to the 12 o'clock direction, and the image noise was measured at the center of the phantom, and the points of 12, 3, 6 and 9 o'clock direction respectively. Some points were placed beyond the scan field of view (SFOV), so that measurement was not possible at that points. The results are as follows: The CTDIw showed a larger decrease as the source goes farther from the iso-center or the BC became wider. The CTDIw depends on the BC width more than the number of the channel of a detector array. The value of CTDIW decreased with increasing BC, but the value decreased 16.6~31.9% in the head phantom scan in air scan and 51.0~64.5% in the body phantom scan. The value of the noise was 3.9~5.9 in the head and 5.3~7.4 in the body except for BC of $2{\times}0.5\;mm$, regardless of the degree of deviation from the iso-center. When a subject was located within the SFOV, the position did not significantly affect image quality even if the subject was out of the center.

• Proceedings of the KOR-KST Conference
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• 1999.10a
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• pp.129-134
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• 1999

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1995.06a
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• pp.49-51
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• 1995

• The Journal of the Korea Contents Association
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• v.10 no.6
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• pp.35-42
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• 2010

Side information generation techniques play a great role in determining the overall performance of the DVC (Distributed Video Coding) coding system. Most conventional techniques for side information generation are mainly based on the block matching algorithm with symmetric motion estimation between the previously reconstructed key frames. But, these techniques tend to show mismatches between the motion vectors and the real placements of moving objects. So these techniques need to be modified so as to search well the real placements of moving objects. To overcome this problem, this paper proposes a block-centered symmetric motion estimation technique which uses the same coordinates with the given block. Through computer simulations, it is shown that the proposed algorithm outperforms the conventional schemes in the objective quality.

• 전자공학회논문지 IE
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• v.46 no.3
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• pp.19-25
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• 2009

In this paper, I suggested the character recognition methods which are used the centroid method and included the spherical transform from the rectangle coordination for the character recognition system and obtained the results of the above 78.14% average differential ratio for the character features. The character feature extraction system using the spherical transform method is suggested in this paper, and the possibilities of the method which is get the invariant feature for the character transition using the centroid are suggested through the differential ratio results.

• Journal of IKEEE
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• v.23 no.2
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• pp.419-424
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• 2019

The FCM algorithm finds the optimal solution through iterative optimization technique. In particular, there is a difference in execution time depending on the initial center of clustering, the location of noise, the location and number of crowded densities. However, this method gradually updates the center point, and the center of the initial cluster is shifted to one side. In this paper, we propose a TI-FCM(Triangular Inequality-Fuzzy C-Means) clustering algorithm that determines the cluster center density by maximizing the distance between clusters using triangular inequality. The proposed method is an effective method to converge to real clusters compared to FCM even in large data sets. Experiments show that execution time is reduced compared to existing FCM.