• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.1C
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• pp.63-75
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• 2012

This paper researched the operation methods of software video teleconferencing on the tactical communication networks under 1Mbps. The tactical communication networks have limited bandwidths, frequent data losses and transmission delays due to the unstable networks. In addition, the bandwidth for video teleconferencing has to be much smaller since the Army Tactical Command Information System(ATCIS) has priority of using the bandwidth. This paper analyzed such restrictions of tactical communication networks, presented some methods to improve the quality of the software video teleconferencing on the tactical communication networks and their actual experiments as well. It is applied in the first place to re-transmit the lost packets and to reduce the image size for the data traffic. Nothing is better for the video teleconferencing than to provide the bandwidth enough for every user. However, on the tactical communication networks with the limited bandwidth, video teleconferencing can be improved by optimizing the compression rate of image data, the number of image frames, the audio codec and the usage of audio compensation data.

• The Transactions of the Korea Information Processing Society
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• v.6 no.7
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• pp.1897-1908
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• 1999

Multimedia services(i.e. teleconferencing and Video on demand) have been developed on MBone. The video and audio data of them require Real-Time service using QoS(Quality of Service) guarantees. RSVP(Resource reSerVation Protocol) on the Internet has been suggested to support QoS guarantees. But currently, it has two problems : complexity and scalability. To solve these problems, this paper describes the design and implement of teleconferencing system with QoS guarantees by simplifying the resource reservation processing to solve the RSVP's complexity and scalability.

• The Transactions of the Korea Information Processing Society
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• v.4 no.2
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• pp.363-376
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• 1997

In this paper, we present a hardware architecture and a sofrware architecture for cimputer based teleconferencing systems.And also we analyse stream adtivation mechanisms for them form the viewpoint of delay. MuX that is a multimedia I/O server provides various processing elements for data I/O, synchronization, interleaving and mixing.We describe methods to build teleconferencing systems with the elements and compares the technique using master click with the techniquie using self clock.In the plase of dta input.the technique using self click is berrer than the technique using master clock.When we generate interleved stream from audio and video stream and activate channel objects by periodic audio stream as activation clock, dealy from imput audio stream to imterleved stream is reduced but delay for video stream is not reduced as much as in the case of audio stream.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1611-1614
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• 2005

In this paper, a new multi-view 3D video communication system for real-time Reality teleconferencing application is proposed by usin gthe IEEE 1394 digital cameras, Intel Xeon server computer system and Microsoft's DirectShow programming library and its performance is analyzed in terms of image-grabbing frame rate and number of views. The captured two-view image data is compressed by extraction of disparity data between them and transmitted to another client system through the communication network, in which multi-view could be synthesized with this received 2-view data using the intermediate view reconstruction technique and displayed on the multi-view 3D display system. From some experimental results, it is found that the proposed system can display 16-view 3D images with a gray of 8bits and a frame rate of 15fps.

• Journal of the Ergonomics Society of Korea
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• v.17 no.1
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• pp.23-36
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• 1998

The primary objective of this research was to establish and quantify the relationship between the physical degradation factors of multimedia telecommunications (teleconferencing) system and Subjective human perception. The research was performed in two stages. A field survey of the real users and pilot experiments were carried out in the first stage to determine customers' major complaints and corresponding system degradation factors. A prototype teleconferencing simulator was developed in two separate sound-treated chambers equipped with audio/video equipment running under a custom-developed software program. In the second stage, simulation experiments using the semantic differential methodology were performed utilizing 26 paid participants (14 college students and 12 housewives). The results indicated that audio/video synchronization and the frame rate were the main system factors for both subject groups, but different pattern of factors' influence was found according to the group, implying that the system configuration would hopefully accommodate the characteristics of the end users. Also, a single quality index, developed for system preference, was revealed to be highly correlated with user satisfaction. The results provide some fundamental data on the human subjective perception of multimedia telecommunications quality, and further can help establish the quality standards to enhance service level.

• Proceedings of the KOSOMBE Conference
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• v.1997 no.05
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• pp.104-107
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• 1997

A medical teleconferencing and medical image transmision system has been developed for diagnosis of the medical images between the medical doctors who are far away. The medical teleconferencing system transmits the voice and image of the doctors using the video and audio capture boards. The medical image transmission system software uses the medical image standard DICOM 3.0 for the future expansibility and the open system interconectivity. The medical images usually use CR images.

• Proceedings of the Korean Information Science Society Conference
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• 2004.10b
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• pp.691-693
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• 2004

비디오 시퀀스에서의 객체 추적은 보안 및 감시 시스템(Security and surveillance system), 비디오 원격 회의(Video teleconferencing)등과 같이 컴퓨터 비전 응용 분야에 널리 이용되어, 정정 그 중요성이 증가하고 있다 여러 가지 이유로 인친 카메라 덜(View)로부터 객체의 가시 상태가 변하는 경우, 하나의 뷰만을 이용해서는 좋은 결과를 가지기 어렵기 때문에 본 논문에서는 객체가 가장 잘 나타나는 뷰를 선택해서 객체를 추적하는 방법을 제안한다. 각각의 카메라 뷰에서 객체를 추적하기 위해 본 논문에서는 다중 후보가 결합된 Mean-shift 알고리즘을 이용한다. 제안된 시스템의 경우, 복잡한 환경으로 인해 객체의 가시 상태가 변하는 환경에서 단일 뷰를 이용하는 경우와 비교해 더 나은 성능을 가질 수 있었다.

• Proceedings of the Korean Information Science Society Conference
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• 1998.10a
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• pp.468-470
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• 1998

최근 영상회의 시스템과 관련하여 해결해야 할 문제 중 데이터 전송시 발생하는 지연에 관한 연구가 진행되고 있다. 본 논문에서는 영상회의 구성을 설명하고 영상회의 시 발생하는 전송 지연을 최소화 방법에 대해서 논한다. 전송 지연을 최소화하기 위해서 근원적으로 오디오와 비디오 데이터를 분리 시켜 전송하므로 전송 시 발생하는 지연을 최소화 시켰다. 또한 이를 효과적으로 지원할 수 있는 동시화 알고리즘을 제안하고, 이 알고리즘을 기반으로 영상회의 시스템을 설계하였다.

• Review of KIISC
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• v.2 no.4
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• pp.37-47
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• 1992

이 논문에서 우리는 여러 가지 분할 항등식을 유도했고 제한된 분할에 관한 새로운 항등식을 증명하고, 분할의 기본적인 이론과 분할함수(Partition Number Function)가 다항식 함수가 아니라는 것을 보이며, n의 분할의 수 p(n)에 대한 ㅎ계(Lower Bound)를 얻기 위해 Stirling의 n !에 대한 근사값을 소개한다. 그리고Hardy-Ramanujan 공식, Euler 항등식과 p(n)의 순환식을 유도하며, 그리고 d$_{m}$ (n)이 n을 m개의 부분으로 분할하는 분할의 수를 나타낼 때 우리는 d$_{m}$ (n) 에 관한 일반적인 공식을 p(n)과 함께 행렬식의 형태로 표현한다.

• Journal of Digital Convergence
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• v.10 no.8
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• pp.317-326
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• 2012

The study aims at analyzing and comparing the effect of video teleconferencing English class with native speakers on class satisfaction and self-efficacy of elementary school students according to grades. Revised Kim's self efficacy and researcher's class satisfaction measuring tools were used for this. Grade 3 got the highest score and grade 6 had the lowest one in class satisfaction. In post-testing on self efficacy, average score was lower than in pre-testing except grade 3. Grade 3 got the highest score and grade 6 had the lowest one in self efficacy. I conclude that as students' grade goes up, their interests decrease in teleconferencing class and native speaker teachers.