• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.6
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• pp.1027-1037
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• 1994

While the value of unidirectional delay was used as the preference of a node in the previous research on the performance of the leader, this paper proposes the value of bidirectional delay as a preference of a node and analyzies election strategies in the case of the various number of candidates through simulation. We made a comparative study to evaluate the quality of leaders chosen by the bidirectional preference and unidirectional preference in terms of relative error and from the standpoint of the probability of choosing the optimal leader.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.1
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• pp.79-85
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• 2016

Recently, visible light communication(VLC) is being actively researched as green wireless communication services are drawing attention. Currently, VLC mostly uses LED for transmission and PD(Photo Diode) for receiving. However, this kind of system has limited applications. Therefore, we design and propose in this paper, a LED-to-LED two way VLC system that doesn't use PD(Photo Diode). This system has the following features and contributions. First, this system uses just LED at both transmitter and receiver with analog switch, Second, this system support both one-way communication and two way communication together. One way communication can support multi-hop communication. The performance evaluation of the proposed system is conducted at a place with standard light. We test the success or failure of one way communication by changing distance and baud rate while test the success and failure of two way communication by changing distance. We expect that the proposed LED-to-LED system in this paper can be applied for various application fields.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.553-556
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• 2013

Currently green growth and energy saving are major issues and solution using low-power LED lighting devices are gaining popularity. There are a few standards to control these LED lighting equipment and DMX512 protocol is a typical communication control standard used. DMX512 lighting control protocol is one of standard protocols widely used in various fields which include mainly stage lighting and landscape lighting. But in DMX512 protocol, line is to be connected to a wired connection. Advantage of wired connection is stable data transfer operation but it adds complexity and certain constraints as well in wired connection. To solve this problem, wired connection can be replaced efficiently with a wireless connection but for wireless, problem of data loss and two way communications arises. In this paper, these problems of wireless communication for DMX512 have been addressed and solutions for two way communications and data loss problem have been proposed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.2C
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• pp.57-64
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• 2011

A two-way relay channel is a bidirectional cooperative communication channel between two nodes using a relay. In many cooperative communication schemes, a relay transmits its data to each node using separate channels. However, in the two-way relay channel, a relay can broadcast the network-coded signal to both nodes in a same time slot, which can increase the system throughput. In this paper, a new cooperative network error correcting scheme using distributed turbo code in a two-way relay channel is proposed. The proposed scheme not only increases the system throughput using network code but also improves the performance by utilizing the LLR information from relay node and other user node through distributed turbo code. Also, a power allocation scheme is investigated for various channel conditions to improve the system performance.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1990.06a
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• pp.663-666
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• 1990

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1990.06a
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• pp.547-550
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• 1990

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1995.06a
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• pp.446-449
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• 1995

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.4C
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• pp.350-357
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• 2010

In this paper, we present an auto-range fast bilateral filter (FBF) for high-dynamic-range (HDR) images, which increases computation speed by using adaptive standard deviations for range filter (RF) of FBF in iCAM06. Many images that cover the entire dynamic range of the scene with different exposure times are fused into one High Dynamic Range (HDR) image. The representative algorithm for HDR image rendering is iCAM06, which is based on the iCAM framework, such as the local white point adaptation, chromatic adaptation, and the image processing transform (IPT) uniform color space. FBF in iCAM06 uses constant standard deviation in RF. So, it causes unnecessary FBF computation in high stimulus range with broad and low distribution. To solve this problem, the low stimulus image and high stimulus image of CIE tri-stimulus values (XYZ) divided by the threshold are respectively processed by adaptive standard deviation based on its histogram distribution. Experiment results show that the proposed method reduces computation time than the previous FBF.

• 한국정보통신설비학회:학술대회논문집
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• 2009.08a
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• pp.301-304
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• 2009

현재의 IPTV 시비스는 VoD+PPV와 같이 단순한 형태로 서비스를 제공하고 있다. IPTV 서비스 사업자들은 IPTV의 새로운 수익모델인 양방항성 통신특성에 최적화된 서비스를 제공해야 한다. 양방향 통신의 대표적인 서비스로는 T-commerce가 있다. T-commerce 서비스 제공시 IPTV 가입자의 정보가 제3의 서비스 사업자로 전송되기 때문에 개방된 IP망에서 가입자의 정보가 전송되므로 개인정보보호의 중요성이 커지게 될 것이다. 양방향 서비스를 제공하면서 개인정보보호를 유지하는 방안으로 ID를 통합적으로 관리하는 기술인 IdM(Identity Management)을 IPTV에 적용하는 방안이 고려되고 있다. 본 논문에서는 NGN(Next Generation Network)기반 IPTV의 IdM 적용방안에 대해 기술한다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.5
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• pp.1-9
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• 2011

Nowadays it is necessary to replace electrical wires with another intelligent connection method because the consumers, who have much experience with mobile smart devices, are expecting easier and smarter connectivity in their home electronics such as wireless linking. In this paper a bidirectional CEC control scheme is newly proposed to expand the controllability from one to two way in a millimeter band image transmission system because two degree of freedom controllability presents more intelligent convenience in HDMI interface systems. Experimental study shows the feasibility of the proposed system as an advanced image transmission solution in millimeter band including an intelligent 2 DOF CEC interface with the performance result of 3.0 Gbps transmission band for 1080p full-HD image steaming.