• 제목/요약/키워드: dual space

검색결과 616건 처리시간 0.025초

Development of a Dual-Circular Polarizer for the KVN Receivers

  • Chung, Moon-Hee;Je, Do-Heung;Han, Seog-Tae;Lee, Jung-Won
    • Journal of Astronomy and Space Sciences
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    • 제26권3호
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    • pp.345-354
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    • 2009
  • A stepped septum polarizer has been designed and fabricated for the 43 GHz band KVN receiver system. The dual-circular polarizer converts left and right hand circularly polarized signals into linear polarizations in two separated rectangular waveguides. Measurements show that the performance of the designed septum polarizer covering 42-48 GHz frequency band is adequate to meet the requirement of KVN receivers. Especially, a polarizer for the KVN receiver of 85-95 GHz frequency band can be fabricated by scaling the dimensions of the septum polarizer developed in this paper.

Maximum Ratio Transmission for Space-Polarization Division Multiple Access in Dual-Polarized MIMO System

  • Hong, Jun-Ki;Jo, Han-Shin;Mun, Cheol;Yook, Jong-Gwan
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제9권8호
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    • pp.3054-3067
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    • 2015
  • The phenomena of higher channel cross polarization discrimination (XPD) is mainly observed for future wireless technologies such as small cell network and massive multiple-input multiple-output (MIMO) system. Therefore, utilization of high XPD is very important and space-polarization division multiple access (SPDMA) with dual-polarized MIMO system could be a suitable solution to high-speed transmission in high XPD environment as well as reduction of array size at base station (BS). By SPDMA with dual-polarized MIMO system, two parallel data signals can be transmitted by both vertically and horizontally polarized antennas to serve different mobile stations (MSs) simultaneously compare to conventional space division multiple access (SDMA) with single-polarized MIMO system. This paper analyzes the performance of SPDMA for maximum ratio transmission (MRT) in time division duplexing (TDD) system by proposed dual-polarized MIMO spatial channel model (SCM) compare to conventional SDMA. Simulation results indicate that how SPDMA utilizes the high XPD as the number of MS increases and SPDMA performs very close to conventional SDMA for same number of antenna elements but half size of the array at BS.

Some Properties of the Closure Operator of a Pi-space

  • Mao, Hua;Liu, Sanyang
    • Kyungpook Mathematical Journal
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    • 제51권3호
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    • pp.311-322
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    • 2011
  • In this paper, we generalize the definition of a closure operator for a finite matroid to a pi-space and obtain the corresponding closure axioms. Then we discuss some properties of pi-spaces using the closure axioms and prove the non-existence for the dual of a pi-space. We also present some results on the automorphism group of a pi-space.

Internal force-based coordinated motion control of dual redundant manipulator

  • Kim, Hyunsoo;Chung, Wan-Kyun;Youm, Youngil
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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    • pp.237-240
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    • 1996
  • Internal Force based control of dual redundant manipulator is proposed. One is resolved acceleration type control in the decoupled joint space which includes null motion space and the other is in the impedance control fashion in which the desired impedances are decoupled in three subspace, internal motion controlled space, orthogonal to that space, and the null motion controlled space. The internal force is formulated with its basis set meaningful. The object dynamics is also briefly evolved beforehand.

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우주 물체 충돌 위험 분석을 위한 이중 모드 프레임워크 (Dual-Mode Framework for Space Object Collision Risk Assessment)

  • 김시우;이진성;최은정;조성기;안재명
    • 우주기술과 응용
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    • 제2권1호
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    • pp.13-29
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    • 2022
  • 최근 지구 주변 우주 물체 수의 급격한 증가와 함께 우주 위험 대응 기술에 대한 중요성이 높아지고 있다. 본 연구에서는 우주 위험 중 하나인 우주 물체 간 충돌 위험을 분석하기 위한 방법론에 대해 기술하였다. 주어진 정보와 상황에 적합한 충돌 위험 정보를 도출하기 위해 일대일 충돌 사건에 초점을 맞춘 미시적 모드와, 관심 대상이 통과하는 공간에 초점을 맞춘 거시적 모드로 이루어진 이중 모드 프레임워크가 제안되었으며, 각 모드에 적합한 사례 연구를 통해 그 효용성을 검증하였다.

저전력 비동기식 시스템 설계를 위한 혼합형 dual-rail data encoding 방식 제안 및 검증 (Mixed Dual-rail Data Encoding Method Proposal and Verification for Low Power Asynchronous System Design)

  • 지화준;김상만;박주성
    • 전자공학회논문지
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    • 제51권7호
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    • pp.96-102
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    • 2014
  • 본 논문에서는 dual-rail data encoding방식을 적용하여 비동기식시스템을 설계할 때, 신호천이를 줄이고 소비전력을 줄이기 위하여 4-phase handshaking 프로토콜과 2-phase handshaking 프로토콜을 혼합한 dual-rail data encoding방식을 제안한다. 기존의 dual-rail data encoding 4-phase handshaking 프로토콜은 space state가 존재함으로 말미암아 신호 천이가 많이 발생하게 되고 많은 전력소비를 발생한다. 이론적으로 dual-rail data encoding 2-phase handshaking 프로토콜은 dual-rail data encoding 4-phase handshaking 프로토콜보다 빠르고 신호천이도 적지만 표준 라이브러리를 사용하여 설계할 수 없다. 제안하는 혼합형 dual-rail data encoding 방식의 성능을 평가하기 위하여 Adder블록, Multiplier블록, Latch를 포함한 benchmark회로를 설계를 설계하였다. Benchmark회로를 이용하여 시뮬레이션해본 결과, 제안하는 혼합형 dual-rail data encoding방식은 기존의 dual-rail data encoding 4-phase handshaking 프로토콜에 비해 35%이상 전력소비가 감소되는 결과를 얻었다.