• Title/Summary/Keyword: space diversity

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A Study on the OFDM System Using Multi-Block SDM (Multi-Block SDM을 이용한 OFDM 시스템에 관한 연구)

  • Lee, Kyu-Jin;Kim, Ji-Sung;Kim, Nam-Il;Lee, Kye-San
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.7 no.5
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    • pp.122-130
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    • 2008
  • Improving the transmission rates of multi-media delivery, such as moving pictures and internet services, has become increasingly important in modern society. To satisfy such high data rate requirements, the MIMO technique, which has the capacity to transmit large amounts of data using limited frequency resources, was developed. The Space Division Multiplexing (SDM) system is one of the MIMO techniques to be able to improve the transmission capacity. However, it is unable to achieve diversity gain because of interference due to the use of multiple antennas. In this paper, an SDM system that utilizes a Multi-Block method as an advanced transmission technique in a wireless communication system to obtain diversity gain is proposed and discussed fur the performance of the proposed system.

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Concatenated Diversity System for Bandwidth Efficient Communication of Flight Type Air Node in Unstable Channel Environments (비정형 통신 채널 환경에서 비행형 에어노드의 대역 효율적인 통신을 위한 연접 다이버시티 시스템)

  • Kang, Chul-Gyu;Park, Jin-Hee;Oh, Chang-Heon
    • Journal of Advanced Navigation Technology
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    • v.16 no.2
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    • pp.247-254
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    • 2012
  • In this paper, we propose a concatenated diversity system to assure the data transmission reliability between flight type air nodes which move according to their atypical orbit, then its performance is analyzed using computer simulation and it is designed with hdl. The proposed system cannot only improve a bandwidth efficient and coding gain from diversity TCM code but also the reliability of data transmission is high. From the computer simulation result about bit error rate(BER) of the proposed system, we confirm that its BER performance is about 11dB greater than TCM code at $10^{-2}$ and about 11dB greater than space time block code at $10^{-3}$ which has a full diversity gain. In addition, when we compare its BER performance with space time trellis code which has both a diversity gain and a coding gain, the performance of the proposed system is greater than about 1.5dB at $10^{-5}$. Lastly, after designing the proposed system with HDL, we can confirm that the operation result is correct.

A Study on the Spatial Presentation Strategies for Cafe as 'The Third Space' - Focused on the cafes located in regions where 'Street culture' was formed - ('제3의 공간'으로서 카페의 공간연출 전략에 관한 연구 - '길(street) 문화'가 형성된 지역을 중심으로 -)

  • Moon, Geun-Yi;Lyu, Ho-Chang
    • Korean Institute of Interior Design Journal
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    • v.22 no.5
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    • pp.68-77
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    • 2013
  • 'The Third space,' which is the concept that embraces sociological, spatial, and marketing concepts, refers to the place which is other than the home and the workplace and which is a comfortable frequented place where meditation, psychological relaxation, and social needs can be satisfied. 'The Third space' has the characteristics of comfort, openness, interactivity, playfulness, and diversity. In modern times, most of consumption spaces play the role of 'the Third space,' and the typical example is $Caf{\acute{e}}$. $Caf{\acute{e}}$ began from its origin with the characteristics of 'the Third space,' and recently it has become the complex cultural space of urban dwellers. $Caf{\acute{e}}$ as 'the Third space' has the characteristics of a healing space, communication space, personalized space, value-expressive space, culture and consumption space, nomad space. Such characteristics of $Caf{\acute{e}}$ are well represented in the cafes around the regions where 'street culture' has recently been formed. As examined through the examples, $Caf{\acute{e}}$ as 'the Third space' can be more strategically produced by establishing themes through storytelling, giving spatial identity through style creation, diversifying the sequence through complex space organization, and establishing interaction devices through experience elements.

A Review of PCA Rules for Arbitration of Disputes Relating to Outer Space Activities (우주활동분쟁에 관한 PCA 중재규칙에 관한 소고)

  • Young-Ju Kim
    • Journal of Arbitration Studies
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    • v.33 no.2
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    • pp.109-137
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    • 2023
  • This paper reviews legal framework, characteristics and main contents of the 'Optional Rules for the Arbitration of Disputes Relating to Outer Space Activity' enacted by the Permanent Court of Arbitration (PCA) in 2011. Space activities, which began in the 1950s, are undergoing significant changes according to the international characteristics and development of science and technology. New Space and the space business will be the key factors driving these changes. However, the diversity of disputes caused by New Space space activities and the characteristics of each type of dispute must be considered together. This is because the space business can be maintained and developed by securing the effectiveness of dispute resolution. This paper identifies that the PCA Space Dispute Arbitration Rules have important legislative and policy significance in this respect. Specifically, in this paper, the international space law system, the draft convention of the International Law Association, and the PCA arbitration rules were introduced in an overview of the international dispute settlement system related to space activities. Afterwards, it examines that the systematic structure and some major contents of the PCA Space Dispute Arbitration Rules in detail. Based on this, the paper suggests some points of application of the PCA Arbitration Rules and the legislative policy implications.

Expansion and Evolution of Artist-in-residence Program: From Structure of Creative City to the Nations' Cooperation (예술가 해외거주 프로그램(Artist-in-residence)의 확산과 진화 - 창조도시 구도에서 국가 간 협력 프로그램까지)

  • Park, Shin-Eui
    • The Journal of Art Theory & Practice
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    • no.6
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    • pp.123-145
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    • 2008
  • Artist-in-residence which gets chances to create by artists' moving and encountering new culture is heightening its level in 21th century. Under the circumstance that issue of cultural diversity and the role of artists which is for city revitalization and sustainability are affect residency program in the midst of highly proceeded globalization that international exchange. Therefore, in the aspect of creative city, a new model is creating by reuse of abandoned industrial facilities and Asia or Eastern country become the subject in residency program management, the issue of cultural diversity is getting more important, programs based on project not just residence are managing. Furthermore, it has inter-country cooperating system in the rage of cultural management. It means that artists' space of creating activity has a new, social role in spontaneously we need to approach to following model in Korea, as well.

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Design of OFDM receiver for 18GHz wireless video transmission (18GHz 객실감시시스템의 터널구간에서의 영상전송특성 시험 18GHz 무선 영상 전송을 위한 OFDM 수신기의 설계)

  • Jeong, Sang-Guk;An, Tae-Ki;Kim, Back-Hyun;Choi, Gab-Bong;Hong, Dong-Kyu
    • Proceedings of the KSR Conference
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    • 2010.06a
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    • pp.2089-2094
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    • 2010
  • The importance of broadband wireless communication implemented at subway tunnels is growing up. At 18GHz wireless video transmission system, the transmitter requires a digital modulation method. At subway tunnel, A 18GHz's influence of the multi-pass padding is strong. OFDM digital modulation that is strong for multi-pass padding is recommended. In this paper, Suitable to a subway wireless video transmission OFDM receiver is designed. OFDM receiver system has 6dB gaion because uses diversity of space diversity and MRC(Maximum Ratio Combining) diversity. The transmitter system use C&ITechnologies's transmitter board. IF frequency of receiver is 480MHz. OFDM modulation parameter is as follow, The bandwidth is 8MHz, The numuber of carrier if 2,000, The modulation methode is QAM16, The guard interval is 1/32.

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Epiphytic Lichens on Chery trees in Korea. (벗나무에 부착된 지의식물의 생태적 연구)

  • Park Seung Tai
    • The Korean Journal of Ecology
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    • v.2 no.1
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    • pp.1-8
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    • 1978
  • Epiphytic lichens were sampled quantitatively on the cherry trees (Prunus serrulata) at Jeonju and Hadong along both north and south exposures of tat trees. Coverage of lichens was determinated for each species by 10*20cm quadrat. Lichen species diversities such as total diversity (D), mean diversity (D), Shannon diversity (D') and redundancy (R) were estimated according to Brillouin and Shannon equation. The importance value of lichen species was meassured by niche preemption model, The importance value transformed into some fraction k of the niche space. The value of k was compared with aggregation of lichens communities in to areas. The ten most important awariensis, Parmelia incurva, Parmelia crinita, Dirinaria applanta, Parmelia wallichiana, Parmelia austrosinensis and Cetraria platyphylla. The mean coverage epiphytic lichens on north side of tree was higher than of south side in two areas. The species diversities of epiphytic lichen of two areas shows that a change in the value of D' along vertical was not paralled with the D and R. In Kumsan-sa, D, D and D' increased upward along the tree of north exposure, but did not follow this trend in south, However in Sangge-sa, D, D and D' of both sides increased.

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Performance Analysis of CDMA-OFDM System via Cooperative Communication in Wireless Fading Environment

  • Jeong Hwi-Jae;Kong Hyung-Yun
    • Journal of electromagnetic engineering and science
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    • v.6 no.3
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    • pp.176-181
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    • 2006
  • Signal distortion due to the path loss, shadow, and multi-path fading is very serious in radio channel. In this paper, we propose CDMA-OFDM cooperative communication system based on DFP(Decode and Forward Protocol) to overcome these phenomena using spread spectrum technique, orthogonal sub-carrier, and the space diversity. We simulated proposed system under Rayleigh flat fading channel environment. A variety of simulation results reveal the cooperation can provide performance gain of up to 12 dB over direct communications in ideal inter-user case at BER of $10^{-3}$. And we can also confirm variation of diversity effect as channel environment changes.

Wireless Ad-hoc Networks Using Cooperative Diversity-based Routing in Fading Channel

  • Kim, Nam-Soo;An, Beong-Ku;Kim, Do-Hyeon;Lee, Ye-Hoon
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.33 no.2B
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    • pp.69-75
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    • 2008
  • We propose new routing scheme, Cooperative Diversity-based Routing (CDR)which utilize the cooperative space diversity for power saving and for performance enhancement of wireless ad-hoc networks. The end-to-end performance of the proposed routing, CDR, is analyzed based on the Haenggi's link model. The improved performance is compared with Multi-hop Relay Routing (MRR) by analytical methods. When the required outage probability is $1{\times}10^{-3}$ at the destination node in ad-hoc networks with 7 nodes, we noticed that each node can save power consumption by 21.5 dB in average, by using our proposed CDR compared to MRR.

Design of the Open-Loop Combined Meandered-Line 1-Layer Radiator for Diversity Antennas with Size-Reduction and Improved Isolation (다이버시티 안테나의 소형화와 격리도 향상을 위한 미앤더 선로와 개방형 루프가 결합된 방사구조의 설계)

  • Mok, Se-Gyoon;Kahng, Sung-Tek;Kim, Yong-Jin
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.61 no.1
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    • pp.110-116
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    • 2012
  • This paper proposes a new diversity antenna which is the base of MIMO, tunable and reconfigurable antennas. The antenna has a small size and high inter-antenna isolation resulting from the compact radiating element comprising a meandered line and an open-loop combined in one limited uniplanar space and a modified T-shaped decoupling structure, respectively. In a WiMAX band, the radiating element and the entire antenna are $0.092{\lambda}$ and $0.2216{\lambda}$ in size, which shows effective size-reduction and the gain and efficiency of the proposed antenna attached to the ground of a handheld device are 3.7dBi and 56% acceptable to the industrial standard.