• 제목/요약/키워드: K-way

검색결과 19,400건 처리시간 0.042초

세라믹 촉매 담체의 내구 설계 기준에 대한 실험 및 수치해석의 비교 (Comparison of Experimental and Numerical Analysis for Durability Design Criteria in Ceramic Catalyst Substrate)

  • 백석흠;조석수
    • 한국정밀공학회지
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    • 제27권9호
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    • pp.58-66
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    • 2010
  • This study examines thermal safety on three-way catalyst that dominates 70 % among whole exhaust gas purification device in 2003. Three-way catalyst durability in the Korea requires 5 years/80,000 km in 1988 but require 10 years/120,000 km after 2002. Three-way catalyst durability in the USA requires 7 years/120,000 km but require 10 years/160,000 km after 2004. Three-way catalyst maintains high temperature in interior domain but maintains low temperature on outside surface. Therefore this device shows tensile stress on outside surface. Temperature distribution of three-way catalyst was acquired by thermal flow analysis for predicted thermal flow parameter. Thermal stress analysis for three-way catalysis was performed based on this temperature distribution. Thermal safety of three-way catalyst was estimated by power law dynamic fatigue life estimation and strength reduction methods for thermal stress.

삼원 촉매의 열적 내구 성능 평가 (A Estimation of Thermal Fatigue Performance in Three-way Catalyst)

  • 이성룡;조석수
    • 한국산학기술학회논문지
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    • 제14권1호
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    • pp.13-19
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    • 2013
  • 국내 승용차용 삼원촉매의 경우 열적 내구성을 만족시키지 못하고 조기 파손되는 사례가 증가하고 있다. 이것은 차량의 배기가스 정화장치의 신뢰성에 치명적 손상을 유발시키므로 삼원촉매의 내구성 평가 모델을 파악할 필요가 있다. 따라서 본 연구에서는 세라믹 모노리스 담체에서 발생되는 열응력을 구한 뒤 강도저하계수모델과 파손확률을 기초로 삼원촉매의 열적 내구성을 평가하였다.

계획예방정비에 따른 Two Way Bidding Pool 가격 변동 (Two Way Bidding Pool Price Change by Maintenance Schedule)

  • 맹근호;허돈;송광재;박종근
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2003년도 하계학술대회 논문집 A
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    • pp.596-598
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    • 2003
  • 본 논문에서는 CBP 가격을 기반으로, TWBP시장의 가격을 분석하였다. KPX가 발표한 SMP와 수요예측자료로 누적입찰자료를 추정하었으며, 이를 이용하여 계획예방정비에 따른 TWBP가격 변동을 시뮬레이션 하였다.

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Ti-42.5at.%Ni-2.0at.%Cu합금의 인장 및 압축에 따른 형상기억특성에 관한 연구 (A Study on the Shape Memory Characteristic Behaviors of Ti-42.5at.%Ni-2.0at.%Cu Alloys in Tension and Compression Condition)

  • 우흥식;조재환;박용규
    • 한국안전학회지
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    • 제24권5호
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    • pp.1-5
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    • 2009
  • NiTiCu alloys can produce a large force per unit volume and operate with a simple mechanism. For this reasons, it has been widely studied for application as a micro actuator. So in this study, one-way and two way shape memory effects of Ti-42.5at%Ni-2.0at%Cu alloys are studied. In the case of one-way shape memory effects, shape memory recoverable stress and strain of this alloys were measured by means of tension and compression tests under constant temperature. The strains by tension and compression stress were perfectly recovered by heating at any testing conditions also shape memory recoverable stress increased to 116 MPa in tension tests and to 260 MPa in compression tests. In the case of two-way shape memory effects, transformation temperatures from thermal cycling under constant uniaxial applied tension and compression loads linearly increased by increasing external loads and their maximum recoverable strain is 3.8% at 100MPa tensile condition and 2.2% at 125 MPa compression condition.

양방향 복호전달 릴레이를 사용하는 레거시 OFDMA 시스템에서의 자원 할당 기법 (Resource Allocation Schemes for Legacy OFDMA Systems with Two-Way DF Relay)

  • 서종필;한철희;박성호;정재학
    • 한국통신학회논문지
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    • 제39A권10호
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    • pp.593-600
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    • 2014
  • OFDMA (orthogonal frequency division multiple access) 시스템은 주파수 선택적 페이딩 문제를 효율적으로 해결하며 최적의 부반송파 및 송신 전력을 할당함으로써 보다 향상된 성능을 얻는다. Two-way 릴레이는 양방향 통신을 통해 기존의 반이중 릴레이보다 향상된 주파수 효율을 제공한다. WiBro와 같은 레거시 OFDMA 시스템에 two-way DF (decode-and-forward) 릴레이를 적용 시 파일롯 재배치 문제와 자가 간섭으로 인한 채널 추정 및 수신 신호 복호가 어려운 문제가 발생한다. 본 논문에서는 WiBro와 같은 레거시 OFDMA 시스템에 적합한 two-way DF 릴레이 자원 할당 기법을 제안한다. 제안된 기법은 릴레이와 연결된 노드를 기지국과 직접 통신하는 노드로 간주하여 부반송파를 할당한다. 그리고 다른 노드가 사용하지 않는 부반송파를 중첩 할당함으로써 직교 할당으로 발생하는 대역폭 손실을 보완한다. 전산모의실험을 통해 제안된 자원 할당 기법의 성능 향상을 검증한다.

New Star Cluster Candidates in the Milky Way Found in the Infrared

  • Ryu, Jinhyuk;Lee, Myung Gyoon
    • 천문학회보
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    • 제38권2호
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    • pp.73.1-73.1
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    • 2013
  • It is believed that the current census of star clusters in the Milky Way is far from being complete, because of high extinction. Taking advantage of recent wide-field infrared surveys (the WISE as well as 2MASS, UKIDSS GPS, and VVV), we search for new star clusters in the central region of the Milky Way (720 $deg^2$-wide area at |1| < $30^{\circ}$ and |b| < $6^{\circ}$). We find 1840 candidates by visual inspection of the WISE images. The spatial distribution of these candidates show a strong concentration along the Milky Way, showing that most of them belong to the Milky Way. Among them, 26 are probably star clusters, considering their morphology, color-magnitude diagrams, and the degree of central concentration of stars. Eighteen of them appear to be very young in the embedded phase, and six of them are considered to be relatively old, showing a developed red giant branch. Implications of the primary results will be discussed.

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3-Way Doherty 증폭기의 선형성 및 효율 개선에 관한 연구 (A Study on Linearity and Efficiency Improvement for 3-Way Doherty Amplifier)

  • 홍용의;양승인
    • 한국전자파학회:학술대회논문집
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    • 한국전자파학회 2005년도 종합학술발표회 논문집 Vol.15 No.1
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    • pp.77-78
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    • 2005
  • In this paper, Compact Microstrip Resonants Cell(CMRC) have been employed to suppress IMD(Intermodulation Distortion) of the 3-Way Doherty amplifier. This method can not only improve the linearly and the efficiency but also is simpler, smaller and more inexpensive than existing linearly methods; (for example Harmonic feedback, Back off, Feed-forward, Predistortion and so on.) Also, the proposed 3-way Doherty amplifier using only one divider has been reduced size of existing 3-Way Doherty amplifier. As a result, the proposed Doherty amplifier using CMRC and only one divider has been improved for the IMD$_3$ by 4.474dBc, and the PAE by 9.199%, respectively.

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차세대 CPU를 위한 캐시 메모리 시스템 설계 (Design of Cache Memory System for Next Generation CPU)

  • 조옥래;이정훈
    • 대한임베디드공학회논문지
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    • 제11권6호
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    • pp.353-359
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    • 2016
  • In this paper, we propose a high performance L1 cache structure for the high clock CPU. The proposed cache memory consists of three parts, i.e., a direct-mapped cache to support fast access time, a two-way set associative buffer to reduce miss ratio, and a way-select table. The most recently accessed data is stored in the direct-mapped cache. If a data has a high probability of a repeated reference, when the data is replaced from the direct-mapped cache, the data is stored into the two-way set associative buffer. For the high performance and fast access time, we propose an one way among two ways set associative buffer is selectively accessed based on the way-select table (WST). According to simulation results, access time can be reduced by about 7% and 40% comparing with a direct cache and Intel i7-6700 with two times more space respectively.

멀티웨이 트리에서의 IP Prefix 업데이트 방안 (IP Prefix Update of Routing Protocol in the Multi-way Search Tree)

  • 이상연;이강복;이형섭
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 2001년도 하계종합학술대회 논문집(1)
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    • pp.269-272
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    • 2001
  • Since Multi-way Search Tree reduces the number of the memory access by increasing the branch factor, it is considered a method to archive the high-speed IP address lookup. Using the combination of initial 16 bit may and Multi-way Search Tree, it also reduces the search time of If address lookup. Multi-way Search Tree consists of K keys and K+1 key pointers. This paper shows how the E update of Multi-way Search Tree which consists of the one pointer within a node can be performed. Using the one pointer within a node, it increases the number of keys within a node and reduces the search time of IP lookup. We also describes IP updating methods such as modification, Insertion and Deletion of address entries. Our update scheme performs better than the method which rebuilds the entire IP routing table when IP update processes.

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