• Journal of the Korean Society for Aviation and Aeronautics
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• v.12 no.3
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• pp.13-24
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• 2004

It is easier to view flow visualization by using a water tunnel rather than a smoke wind tunnel because of low speed at same Reynolds number. Using a water tunnel also produces more definite flow visualization by the use of various color dyes. The flow uniformity in test section is very significant for accuracy of the test because most flow experiments elicit results through the installation of a model in uniform flow. The purpose of small-size desktop-type water tunnel is not to produce quantitative measurements, but rather to give a visualization of the fluid flow phenomenon. However, uniformity in the test section affects the accuracy of the results. Accordingly, this research estimates uniformity in a water tunnel test section by using the commercially available CFD code FLUENT. Results of the CFD analysis show that the flow uniformity of the test section is good.

• Proceedings of the Korean Information Science Society Conference
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• 2003.04c
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• pp.561-563
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• 2003

Ubiquitous computing 환경에서 휴대용 단말기는 중요한 위치를 차지하고 새로운 Interface와의 연결을 통해 다양한 어플리케이션이 생성하게 된다. 본 논문에서는 휴대용 단말기와 칼라코드 인터페이스를 이용하여서 새로운 형태의 온-오프라인 통합 상거래 서비스 시스템을 제안하고자 한다. 휴대용 단말기를 이용해서 오프라인 쇼핑의 눈으로 볼 수 있다는 정과 온라인 쇼핑의 장바구니 기능과 검색기능을 합친 새로운 형태의 쇼핑을 지원하는 시스템이다. 사용자는 물건의 칼라코드를 인식함으로써 물건의 내역을 입력받고 전자 결제를 사용함으로써 손쉽게 결제할 수 있는 장점을 얻게 되고 대형마켓에서는 인력 절감과 편리한 서비스를 제공한다는 장점이 있다.

• Proceedings of the Korea Contents Association Conference
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• 2003.05a
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• pp.245-250
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• 2003

Of all wireless technologies for personal communications, CDMA(Code Devision Multiple Access) offers the best combination of good signal quality, high security and system reliability. CDMA2000 provides Internet and internet services for variable multimedia aplications. However, good educational CDMA web contents, which focus on the easy understability and good readability, are rare dute to the difficulties and the broad range of CDMA technologies. This content is developed based upon the following two aspects. First, a basic CDMA communication theoy, which contains much color figures and animation, is introduced combing the experimental results and corresponding explanations utilizing the information obtained by the TIMS CDMA equitments. It can improve the understabiliy virtual experience of the site visitors interested in the CDMA. Secondly, the recent CDMA coverage prediction and engineering technology is introduced using the RF plan tool C24 combined for the CDMA engineers

• Proceedings of the Korea Information Processing Society Conference
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• 2003.11a
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• pp.41-44
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• 2003

본 논문에서는 저작권 보호를 위하여 칼라 영상에서의 하다마드 변환을 이용한 워터마킹 기법을 제안한다. 하다마드 변환은 간단한 행렬값으로 사용할 수 있고, 고속변환이 가능하여 영상적용에 용이한 변환이다. 제안한 알고리즘은 RGB 영상을 YIQ 영역으로 전환한 후, Y 영상을 $8{\times}8$의 크기를 갖는 블록으로 나누어서 $H_{3}$ 행렬값을 사용하여 하다마드 변환을 한 후, PN-Code를 이용하여 좌표를 결정하여 워터마킹 알고리즘에 의하여 워터마크를 삽입한다. 실험결과 압축이나 이미지 영상처리 공격에 대해서 강인하게 워터마크가 추출되었고, 추출된 워터마크의 왜곡정도가 양호하여 시각적으로인지가 가능하였다.

• The KSFM Journal of Fluid Machinery
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• v.10 no.4
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• pp.39-46
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• 2007

In large pump station, vortex generation such as free-surface vortex and submerged vortex occurring around pump intake, or at bell-mouth inlet has been an important flow characteristics which should be considered always to keep away the suction of air-entrained or cavitated flow. In this study, a commercial CFD code was used to predict accurately the vortex generation for the specified intake design. These result shows the preliminary result of submerged vortex prediction for the Turbo-machinery Society of Japan Sump Test CFD standard model. At bottom wall, air volume fraction (red color) was found in a large scale to explain the submerged vortex generation at particular operation and configuration condition. And these indicate the free surface formation behind the bell mouth. Particularly, non-uniform approaching flow is a major parameter to govern the occurrence of the free-surface vortex. Futhermore the comparison between turbulence ($k-{\epsilon}$ & $k-{\omega}$ model) mode were executed in this study.

• Proceedings of the IEEK Conference
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• 2003.07b
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• pp.1149-1152
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• 2003

Now a days, many different kinds of display technologies such as Liquid Crystal Display (LCD), Organic Light Emitting Diode (OLED), and Liquid Crystal On Silicon (LCOS) are designed. And these display technologies will be used in many application products like High Definition Televisions (HDTVs) or mobile devices. In this paper, pattern generation circuit for display test is proposed. The proposed circuit will be embedded in the control circuit of display chip. Two differenct kinds of patterns is generated by the circuit. One is block pattern for color test, and the other is line pattern for pixel test. The shape of test pattern is determined by the values of registers in pattern generation circuit. The circuit is designed using Verilog HDL RTL code.

• International Journal of Contents
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• v.8 no.1
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• pp.16-22
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• 2012

In this paper we propose a method for verifying video in a video telephony system implemented in DM6446 DaVinci Processor. Each frame is categorized either error free frame or error frame depending on the predefined criteria. Human face is chosen as a basic means for authenticating the video frame. Skin color based algorithm is implemented for detecting the face in the video frame. The video frame is classified as error free frame if there is single face object with clear view of facial features (eyes, nose, mouth etc.) and the background of the image frame is not different then the predefined background, otherwise it will be classified as error frame. We also implemented the image histogram based NCC (Normalized Cross Correlation) comparison for video verification to speed up the system. The experimental result shows that the system is able to classify frames with 90.83% of accuracy.

• Proceedings of the Korean Information Science Society Conference
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• 2001.04b
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• pp.406-408
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• 2001

인간 사이의 상호작용이 증대됨에 따라 명함과 같은 인적 정보의 교환도 더욱더 많아지고 있으며 이에 따른 효율적 사용과 관리에 어려움이 커지고 있다. 그러므로 인적정보를 디지털화하여 실세계와 사이버세계를 연결하여 관리할 수 있다면 보다 다양하고 편리한 서비스를 이용할 수 있을 것이다. 본 논문에서는 컬러 코드를 이용한 온.오프라인 통합 개인정보 관리 시스템인 CPIMS(Colorcode personal Information Management System)를 개발하였다. 사용자는 컬러 코드가 인쇄된 명함을 받았을 때 명함 중인의 개인 정보를 주소록에 자동으로 입력 받을 수 있게 된다. 그리고 명함주인의 정지화상 및 동영상이나 음성메시지 등과 같은 부가 정보도 제공받을 수 있는 특징을 가진다. 이러한 원리는 명함에 부착된 컬러 코드를 PC 카메라를 사용하여 인식하게 하고 상응하는 정보를 데이터베이스에서 불러오는 것이다. PC 카메라의 보급과 PDA, IMA-2000 등의 카메라가 장착되는 이동컴퓨팅 장비의 사용이 확대되고 있으므로 본 논문에서 제안한 시스템은 온.오프라인을 통합하는 효과적인 미디어 시스템이 될 것으로 기대된다.

• The Korean Journal of Applied Statistics
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• v.16 no.1
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• pp.129-140
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• 2003

This study was to develop a fruit sorting system using statistical image processing. Histogram was used to compare fruit colors to standard fruit color and edge detector using Wilcoxon test was used to calculate an accurate geometrical characteristics of fruit including perimeter, area, major axis and minor axis length and roundness. The experimental result obtained from using our system for sorting apples was presented.

• Journal of Astronomy and Space Sciences
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• v.14 no.1
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• pp.33-43
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• 1997

New BVR CCD photometric observations of EB type close binary V388 Cyg were obtained at the Sobaeksan Astronomy Observatory during 10 nights from October to December 1995. We analyse new 3 color (B, V & R) light curves simultaneously using the Wilson-Devinney code. Now, it is not yet clear whether V388 Cyg is contact or semidetached system. Published epochs of times of minima to data were used to study the changes in period of the system, and calculated a new light elements with the secular terms, $-4.83{\times}10^{-10}$, which indicated the continuous decrease of the period.