• Title/Summary/Keyword: diversity antenna

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The Study of Alamouti Transmission for Improvement of Wireless Communication Based Train Control (CBTC) System (무선통신 기반의 열차제어시스템 성능 향상을 위한 Alamouti 방식 적용에 관한 연구)

  • An, Yun-Sub;Kim, Dong-Ho;Jenong, Deuk-Young
    • Proceedings of the KSR Conference
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    • 2010.06a
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    • pp.1680-1684
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    • 2010
  • CBTC(Communication-Based Train Control) system which is based on wireless communication can provide high density operation of the train using location tracking between ground and onboard train. It can also reduces maintenance expense because it does not require the ground equipment for tracking circuit and signal flag and so on. Recently, research and interest have been done on CBTC system. The high-speed trains up to 300km/h experience multi-path fading channel which bring about the performance degradation of wireless CBTC system. In this paper, we consider MIMO (Multi-Input Multi-Output) antenna-based CBTC system for trains with Alamoutip-type space-time diversity transmission for reliable communication. Also we model a channel considering practical environment and evaluate performance improvement of proposed CBTC system.

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First Record of Paranebalia longipes (Crustacea: Phyllocarida: Leptostraca) from South Korea

  • Song, Ji-Hun;Kim, Min-Seop;Min, Gi-Sik
    • Animal Systematics, Evolution and Diversity
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    • v.28 no.4
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    • pp.221-229
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    • 2012
  • Paranebalia longipes (Willemoes-Suhm, 1875) is cosmopolitan and has been usually found in the algal and sponge debris on the sandy mud substrates. This species can be clearly distinguished from other species of Paranebalia by the presence of serration on posterior margin of pleopods, the number of articles on antennule and antenna, and number of teeth on flange of antennule fourth article. The genus Paranebalia is new to Korea. In this paper, we provide detail descriptions of the diagnostic characteristics and illustrations of the P. longipes. Additionally, type locality and world distribution of the genus Paranebalia are provided.

First Record of the Genus Paragrandidierella (Crustacea: Amphipoda: Aoridae) from Korea

  • Jung, Tae Won;Yoon, Seong Myeong
    • Animal Systematics, Evolution and Diversity
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    • v.29 no.3
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    • pp.259-266
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    • 2013
  • A newly recorded aorid species, Paragrandidierella minima Ariyama, 2002, from Korean waters is reported with a description and illustrations, and its generic features are considered. This species is characterized by the carpochelate gnathopod 1 in matured male, the posterodistal protrusion on peduncle 5 of antenna 2, the absence of the apical spine on inner plate of maxilliped, the minute apical projection on inner lobe of lower lip, the acute posteroproximal extension on the basis of each pereopod 5 and 6, the shape of uropods and telson, and the large inter-ramal process of uropod 1. This is the first report of the genus Paragrandidierella from Korea.

Multichannel Blind Equalization using Multistep Prediction and Adaptive Implementation

  • Ahn, Kyung-Seung;Hwang, Ho-Sun;Hwang, Tae-Jin;Baik, Heung-Ki
    • Proceedings of the IEEK Conference
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    • 2001.06a
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    • pp.69-72
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    • 2001
  • Blind equalization of transmission channel is important in communication areas and signal processing applications because it does not need training sequence, nor does it require a priori channel information. Recently, Tong et al. proposed solutions for this problem exploit the diversity induced by antenna array or time oversampling, leading to the second order statistics techniques, fur example, subspace method, prediction error method, and so on. The linear prediction error method is perhaps the most attractive in practice due to the insensitive to blind equalizer length mismatch as well as for its simple adaptive filter implementation. Unfortunately, the previous one-step prediction error method is known to be limited in arbitrary delay. In this paper, we induce the optimal delay, and propose the adaptive blind equalizer with multi-step linear prediction using RLS-type algorithm. Simulation results are presented to demonstrate the proposed algorithm and to compare it with existing algorithms.

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Adaptive Eigenvalue Decomposition Approach to Blind Channel Identification

  • Byun, Eul-Chool;Ahn, Kyung-Seung;Baik, Heung-Ki
    • Proceedings of the IEEK Conference
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    • 2001.06a
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    • pp.317-320
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    • 2001
  • Blind adaptive channel identification of communication channels is a problem of important current theoretical and practical concerns. Recently proposed solutions for this problem exploit the diversity induced by antenna array or time oversampling leading to the so-called, second order statistics techniques. And adaptive blind channel identification techniques based on a off-line least-squares approach have been proposed. In this paper, a new approach is proposed that is based on eigenvalue decomposition. And the eigenvector corresponding to the minimum eigenvalue of the covariance matrix of the received signals contains the channel impulse response. And we present a adaptive algorithm to solve this problem. The performance of the proposed technique is evaluated over real measured channel and is compared to existing algorithms.

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A New Species of Anthessius (Copepoda, Poecilostomatoida , Anthessiidae) from the Pen Shell, Atrina pectinata (Linn) in Korea (한국산 키조개에서 채집된 Anthessius (Copepoda, Poecilostomatoida , 'Anthessidae)의 1 신종)

  • 서해립;최상덕
    • Animal Systematics, Evolution and Diversity
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    • v.7 no.1
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    • pp.45-54
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    • 1991
  • An anthessiid copepod ; Anthessius atrinae n.sp., is described based on the specimens recorved in the mantle cavity of Atrina pectinata (Linn) taken from Korean waters. This is distinguished from congeners by formula II, I, 5 on distal segment of exopod of the fourth leg, three terminal claws on distal segment of the second antenna , and the shape of caudal ramus.

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Complete Larval Development of Gaillardiellus orientalis (Odhner, 1925) (Crustacea : Decapoda: Xanthidae) Reared in the Laboratory (털부채게 (갑각 강: 십각 목: 부채게 과)의 유생 발생)

  • 고현숙
    • Animal Systematics, Evolution and Diversity
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    • v.15 no.1
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    • pp.51-65
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    • 1999
  • Gaillardiellus orientalis (Odhner, 1925) has been reared in the laboratory, form hatching to the first young crab stage at $25^{\circ}C$. The four zoeal stages and one megalopal stage are described and illustrated in detail. Within the subfamily Actaeinae, the zoea of G. orientalis differs from the other known zoeae in the characteristics of the antenna and the telson.

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A comparison study of the performance and computational complexity of various MIMO technoques in WiBro downlink system (WiBro 다운링크 환경에서 여러 가지 MIMO 기법의 성능 및 연산량에 대한 비교 연구)

  • Hong, Gyeong-Hua;Oh, Tae-Youl;Choi, Seung-Won
    • Journal of Korea Society of Digital Industry and Information Management
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    • v.4 no.2
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    • pp.49-55
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    • 2008
  • Combining OFDMA with MIMO is the key technology for the 4G mobile communication. OFDMA can relieve inherent difficulties of high-speed transmission. MIMO technology can be largely categorized into two techniques: one is STC for diversity gain and the other is SM for high frequency efficiency. In this paper, we depict various MIMO techniques of two transmit antenna and compare the computational complexity of decoding process for the techniques. Then, we analysis the performance of the techniques in the WiBro downlink environment based on OFDMA. We perfer ML algorithm which is the optimum performance and ZF algorithm of least computational complexity for SM detection.

Decision Feedback Detector for Space-Time Block Codes over Time-Varying Channels

  • Ahn, Kyung-Seung;Baik, Heung-Ki
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.28 no.5C
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    • pp.506-513
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    • 2003
  • Most existing space-time coding (STC) schemes have been developed for flat fading channels. To obtain antenna diversity gain, they rely on channel state information (CSI) required at the receiver through channel estimation techniques. This paper proposes a new decision feedback decoding scheme for Alamouti-based space-time block coding (STBC) transmission over time-selective fading channels. In wireless channels, time-selective fading effects arise mainly due to Doppler shift and carrier frequency offset, Modelling the time-selective fading channels as the first-order Gauss-Markov processes, we use recursive algorithms such as Kalman filtering, LMS and RLS algorithms for channel tracking. The proposed scheme consists of the symbol decoding stage and channel tracking algorithms. Computer simulations confirm that the proposed scheme shows the better performance and robustness to time-selectivity.

Modiolicola avadeevi, a New Sabelliphilid Copepod (Poecilostomatoida) from a Bivalve in the Sea of Japan (동해의 털담치(이매패류)에 공생하는 요각류 1신종, Modiolicola avdeevi)

  • Kim, Il-Hoi
    • Animal Systematics, Evolution and Diversity
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    • v.11 no.3
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    • pp.315-321
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    • 1995
  • A new species of Copepoda, Modiolicola avdeevi (Poecilostomatoida, Sabelliphilidae) associated with the bivalve Modiolus difficilis Kuroda and Habe in the Sea of Japan, is described . Although resembling close to Modiolicola bifidus Tanaka, 1961 in the body form, the new species is distinguished from M.bifidus by the more slender antenna, stouter caudal rami and more slender leg 5.

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