• Journal of Korea Society of Digital Industry and Information Management
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• v.6 no.3
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• pp.103-109
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• 2010

Total performance is improved by minimizing the channel interference between links in wireless mesh networks (WMNs). The paper refines on the CB-CA [1] to be suitable for multi-radio multi-channel (MRMC) WMNs. The CB-CA is the cluster-based channel assignment algorithm for one radio three channel WMN based on IEEE 802.11b/g. The CB-CA does not perform the channel scanning and the channel switching between the cluster heads (CHs) and the edge gateway nodes (EGs). However, the use of co-channel for links between CHs and EGs brings the problem of channel interference among many nodes. We propose and evaluate an improved CB-CA algorithm to solve this problem in MRMC WMNs. The proposed algorithm discriminates between transmission channel and receive channel and assigns channels to each interface randomly and advertises this information to neighbor clusters in order to be assigned no-interference channel between clusters. Therefore, the proposed algorithm can minimize the interference between clusters and also improve QoS, since it can use multiple interfaces and multiple channels.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.10a
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• pp.609-610
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• 2017

Cognitive radio communication techniques have been attracting attention to efficiently use the scarce spectrum as the wireless communication service increases. In cognitive radio communication, efforts to minimize interference to the primary user are important technical factors. In a multi-hop wireless ad hoc network, multi-hop transmission requires path and channel selection considering channel interference as well as collision with primary users. In the multi-channel environment, cognitive radio network has different capacities depending on the inter-channel interference and collision with the main users. In this paper, we propose a multi-hop transmission scheme that minimizes inter-channel interference and reduce collision with primary users.

• Proceedings of the IEEK Conference
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• 2003.07a
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• pp.422-425
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• 2003

Software reconfigurable radio will give future users a number of benefits like global roaming, multi mode, multi band, and multi standard. It will also offer complete programmability and reconfigurability to both multi mode and multi functional communication terminal and network nodes. This configuration will be implemented by application of different combination of radio configurable software. In this paper, It proposes the algorithm needed for reconfiguration with basic explanation of the software download. A description of an implementation such reconfiguration processes as partial download and full download and critical and non-critical download installation using the registration table in included.

• Journal of Korea Society of Digital Industry and Information Management
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• v.12 no.4
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• pp.81-87
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• 2016

Recently, as the heterogeneous network (HetNet) has been deployed widely to support various kinds of Radio Access Networks(RANs) with a combination of Macro, Pico, and/or Femto cells, research and standardization efforts have been very active regarding the concept of Licensed Shared Access (LSA) for supporting spectrum sharing. In order for a mobile device to efficiently support the spectrum sharing, the mobile device shall be reconfigurable, meaning that its radio application code has to be adaptively changed in accordance with the hopping of desired spectral band. Especially, Working Group 2 (WG2) of Technical Committee (TC) Reconfigurable Radio System (RRS) of European Telecommunications Standards Institute (ETSI) has been a main driving force for developing standard architecture for Multi-mode Mobile Device (MD) that can be applied to the LSA system. In this paper, we introduce the Multi-mode MD architecture for supporting LSA-based spectrum sharing. An implementation of a test-bed of Multi-mode MD is presented in order to verify the feasibility of the standard MD architecture for the purpose of LSA-based spectrum sharing through various experimental tests.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.11
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• pp.1574-1580
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• 2021

This paper designs and presents the results of an air network simulation radio transmission link applied with a multi-beam active phase array antenna simulator in a testbed system for verifying an air network currently underway as a technology development task. Using the Ku band, the Radio transmission link was designed in consideration of the link budget to satisfy the requirements for the system being developed. Considering short-distance links and long-distance links, the required EIRP and G/T performance scales of multi-beam repeaters and mission planes were applied to confirm the minimum and maximum link margins based on Eb/No. In this Radio Transmission Link design, the application analysis results such as rainfall availability are used to effectively establish standards when selecting the operating radius of the multi-beam relay system and related system standards.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.05a
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• pp.911-914
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• 2009

멀티 네트워크는 여러 무선 접속 기술을 동시에 접속할 수 있도록 구성된 시스템으로 정의되며 Ambient Networks(ANs) 프로젝트로 연구가 진행 중에 있다. 우선 ANs은 여러 다른 무선 장치와 Multi-Radio Access(MRA) 기술이 군집된 동적 통신 환경에서의 네트워킹 개념이다. 따라서 3 세대로 불리는 Global System for Mobile communications(GSM), Universal Mobile Telecommunications System(UMTS) 그리고 무선랜(WLAN)등 다양한 네트워크 인터페이스로 구성된 mobile terminal(MT)이 다양한 무선 접속 기술을 지원하는 멀티네트워크에 접속하여 "Always Best Connected" 관점에서 효율적 접속 서비스를 제공 받아야 한다. 본 논문에서는 멀티네트워크 환경에서 단말에 high-performance를 제공하기 위한 자원관리 모델인 MRRM/RARM(Multi-Radio/Radio Access Resource Management)과 GLL(Generic Link Layer)에 대한 기술 요소를 정의하고 분석한다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.05a
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• pp.481-484
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• 2009

멀티 네트워크는 여러 무선 접속 기술을 동시에 접속할 수 있도록 구성된 시스템으로 정의되며 Ambient Networks(ANs) 프로젝트로 연구가 진행 중에 있다. 우선 ANs은 여러 다른 무선 장치와 Multi-Radio Access(MRA) 기술이 군집된 동적 통신 환경에서의 네트워킹 개념이다. 따라서 3 세대로 불리는 Global System for Mobile communications(GSM), Universal Mobile Telecommunications System(UMTS) 그리고 무선랜(WLAN)등 다양한 네트워크 인터페이스로 구성된 mobile terminal(MT)이 다양한 무선 접속 기술을 지원하는 멀티네트워크에 접속하여 "Always Best Connected" 관점에서 효율적 접속 서비스를 제공 받아야 한다. 본 논문에서는 멀티네트워크 환경에서 단말에 high-performance를 제공하기 위한 자원관리 모델인 MRRM/RARM(Multi-Radio/Radio Access Resource Management)과 GLL(Generic Link Layer)에 대한 기술 요소를 정의하고 분석한다.

• Journal of Broadcast Engineering
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• v.12 no.4
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• pp.333-341
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• 2007

Multi-view video has recently gained much attraction from academic and commercial fields because it can deliver the immersive viewing of natural scenes. This paper presents multi-view video processing being composed of intermediate view reconstruction (IVR), graphics composition, and multi-view video viewer. First we generate virtual views between multi-view cameras using depth and texture images of the input videos. Then we mix graphic objects to the generated view images. The multi-view video viewer is developed to examine the reconstructed images and composite images. As well, it can provide users with some special effects of multi-view video. We present experimental results that validate our proposed method and show that graphic objects could become the inalienable part of the multi-view video.

• Journal of Astronomy and Space Sciences
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• v.23 no.1
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• pp.19-28
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• 2006

The noise temperature of existing millimeter-wave receivers is already within two or three times quantum noise limit. One of practical ways to increase the observation speed of single dish radio telescope without longer integration time is use of multi-beam focal plane array receiver as demonstrated in several large single dish radio telescopes. In this context the TRAO (Taeduk Radio Astronomy Observatory), which operates a 143n Cassegrain radio telescope, is planning to develop a 4 x 4 beams focal plane array SIS receiver system for 86-115 GHz band. Even though millimeter-wave HEMT LNA-based receivers approach the noise temperature comparable to the SIS receiver at W-band, it is believed that the receiver based on SIS mixer seems to offer a bit more advantages. The critical part of the multi-beam array receiver will be sideband separating SIS mixers. Employing such a type of SIS mixer makes it possible to simplify the quasi-optics of receiver. Otherwise, an SSB filter should be used in front of the mixer or some sophisticated post-processing of observation data is needed. In this paper we will present a preliminary design concept and components needed for the development of a new 3 mm band multi-beam focal plane array receiver.

• Journal of Broadcast Engineering
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• v.11 no.4 s.33
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• pp.458-470
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• 2006

This paper describes issues and consideration on authoring of interactive multi-view visual content based on MPEG-4. The issues include types of multi-view visual content; scene composition for rendering; functionalities for user-interaction; and multi-view visual content file format. The MPEG-4 standard, which aims to provide an object based audiovisual coding tool, has been developed to address the emerging needs from communications, interactive broadcasting as well as from mixed service models resulting from technological convergence. Due to the feature of object based coding, the use of MPEG-4 can resolve the format diversity problem of multi-view visual contents while providing high interactivity to users. Throughout this paper, we will present which issues need to be determined and how they can be realized by means of MPEG-4 Systems.