• Title/Summary/Keyword: Pivot

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Unsteady Fluid Forces Acting on a Pitching Foil (피칭 운동익에 작용하는 비정상 유체력)

  • Yang, C.J.
    • The KSFM Journal of Fluid Machinery
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    • v.8 no.6 s.33
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    • pp.47-54
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    • 2005
  • An oscillating foil can produce a driving force through the generation of a reversed $K\'{a}rm\'{a}n$ vortex street, and it can be expected to be a new highly effective propulsion system. A simple pitching foil model was made and it was operated within a water channel. The wake formation behind a pitching foil was visualized and unsteady fluid forces were measured using a 6-axis force sensor based on force and moment detectors. We have been examined various conditions such as reduced frequency, amplitude and pivot point in NACA 0010. The results showed that thrust coefficients increased with a reduced frequency. We also presented the experimental results on the characteristics of a pitching foil at various parameters.

Three OOP Haptic Simulator for a Needle Biopsy (3자유도 힘반향 장치를 이용한 침생검 햅틱 시뮬레이터)

  • 권동수;경기욱;감홍식;박현욱;나종범
    • 제어로봇시스템학회:학술대회논문집
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    • 2000.10a
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    • pp.539-539
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    • 2000
  • This paper shows how to implement force reflection for a needle insertion problem. The target is a needle spine biopsy simulator for tumor inspection by needle insertion. Simulated force is calculated from the relationship of volume graphic data and the orientation and Position of the needle, and it is generated using PHANTOM$^{TM}$. To generate realistic force reflection, the directional force of the needle has been generated by tissue model. The other rotational force is generated using a pivot to keep the needle in the initial inserted direction after puncturing the skin. Since the used haptic device has limitation for generating high stiffness and large damping, scale downed model and digital filter are used to stabilize the system.m.

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A Study on the Modeling and Control of High-Speed/High-Accuracy Position Control System (고속/정밀 위치제어시스템의 모델링 및 제어에 관한 연구)

  • 신호준;박민규;윤석찬;한창수
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2000.10a
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    • pp.83-89
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    • 2000
  • This paper presents a dynamic modeling and a sliding mode controller for the high-speed / high-accuracy position control system. Selected target system is the wire bonder head assembly which is used in semiconductor assembly process. This system is a reciprocating one around the pivot point that consists of VCM(voice coil motor) as a actuator and transducer horn as a bonding tool. For the modeling elements, the system is divided into electrical circuit, magnetic circuit and mechanical system. Each system is modeled by using the bond graph method and united into the full system. Two major aims are considered in the design of the controller. The first one is that the horn must track the given reference trajectory. The second one is that the controller must be realizable by using the DSP board. Computer simulation and experimental results show that the designed sliding mode controller provides better performance than the PID controller.

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Modeling of Lateral Dynamics of a Moving Web by Using the System Identification Technique (System Identification 기법을 이용한 이송중인 웹의 사행 거동에 대한 모델링)

  • 권순오;김상훈;신기현
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2002.10a
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    • pp.624-627
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    • 2002
  • Experimental study showed that the existing mathematical model doesn't fully describe the lateral motion of a moving web fur different operating conditions. So, a physically interpretable model of lateral motion of a moving web in a typical web guidance system, operated at Konkuk Univ., was developed using the system identification technique. A well-known Least Square Method based on ARX model was used for the system identification. Lateral displacement of the web was measured at the exit of each span by infrared sensors. The model obtained from identifying a linear time-invariant system for a typical operating condition yields an improved prediction capability of the lateral dynamics of the moving web compared to other mathematical models proposed in literature.

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The Study on Park Designing for Users of Common Residential Room (공동주거 공간의 이용자 중심형 공원계획에 대한 연구)

  • Cho, Kyoung-Deuk
    • Journal of The Korean Digital Architecture Interior Association
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    • v.7 no.1
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    • pp.35-42
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    • 2007
  • Common residential environment is synthetic forms promote with organic organization of varied cultures and images. Users perceive and classify about these environments of feeling and atmosphere of each elements through their experiences and memories, not fixed point of view. In Korea, park designing of common residential room is in operation monotonously attach importance to economical efficiency without aesthetic structures, varied tries of materials, multiplicity, congruity of surrounding, and user-oriented plan. Recently, in policy of park designing has elements that obstruct to characteristic of environment because of applied to wrong guidelines which are end in investigation to model of an advanced countries'. In conclusion, this investigation shows improve on quality of park planning with the pivot of the matter is for users of common residential room. and park planning needs to multidimensional achieve.

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An Implementation of Preprocessing for Interior Point Methods for Linear Programming (내부점 방법을 위한 사전처리의 구현)

  • 성명기;임성묵;박순달
    • Journal of the Korean Operations Research and Management Science Society
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    • v.24 no.1
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    • pp.1-11
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    • 1999
  • We classified preprocessing methods into (1) analytic methods, (2) methods for removing implied free variables, (3) methods using pivot or elementary row operations, (4) methods for removing linearly dependent rows and columns and (5) methods for dense columns. We noted some considerations to which should be paid attention when preprocessing methods are applied to interior point methods for linear programming. We proposed an efficient order of preprocessing methods and data structures. We also noted the recovery process for dual solutions. We implemented the proposed preprocessing methods. and tested it with 28 large scale problems of NETLIB. We compared the results of it with those of preprocessing routines of HOPDM, BPDPM and CPLEX.

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A Study on Electric Data Interchange System with Format Server under Intranet Environments (인트라넷 환경하에서 문서형식 서버를 갖는 전자문서교환 시스템에 관한 연구)

  • Chang, Tae-Woo;Sung, Che-Hoon;Seo, Yong-Won;Hahm, Ju-Ho
    • IE interfaces
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    • v.10 no.3
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    • pp.55-62
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    • 1997
  • Among the driving methods of CALS, Electronic Data Interchange (EDI), the pivot of procurement and logistics, is becoming the standard of data interchange. In this article, we examine the standard, growth, and status of EDI, and present a scheme to make it available via Internet that grow to be a standardized network, in comparison with a method to use a Value Added Network(VAN). So we studied an implementation of EDI system to exchange and process the business intra-works in order to integrate it into Intranet environment. As well, we present a client/server model running under Intranet environment, and a system with a format server to share the load of server and client. To do this, we list the functions and requirements of EDI system, connect a database to the Intranet, and develop applications using $Java^{TM}$.

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An Optimal Parallel Sort Algorithm for Minimum Data Movement (최소 자료 이동을 위한 최적 병렬 정렬 알고리즘)

  • Hong, Seong-Su;Sim, Jae-Hong
    • The Transactions of the Korea Information Processing Society
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    • v.1 no.3
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    • pp.290-298
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    • 1994
  • In this paper we propose parallel sorting algorithm, taking 0( $n^{n}$ log n) time complexity, 0( $n^{x}$ log n) cost (parallel running time * number of processors) and 0( $n^{1-}$x+ $n^{x}$ )data movement complexity under the ERWW- PRAM model. The methods for solving these problems similar. Parallel algorithm finds pivot for partitioning the data into ordered subsets of approximately equal size by using encording pointers..

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Research about SMT Performance Improvement Through Automatic Corpus Expansion (말뭉치 자동 확장을 통한 SMT 성능 향상에 대한 연구)

  • Choi, Gyu-Hyun;Shin, Jong-Hun;Kim, Young-Kil
    • Annual Conference on Human and Language Technology
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    • 2016.10a
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    • pp.296-299
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    • 2016
  • 현재 자동번역에는 통계적 방법에 속하는 통계기반 자동번역 시스템(SMT)이 많이 사용되고 있지만, 학습 데이터로 사용되는 대용량의 병렬 말뭉치를 수동으로 구축하는데 어려움이 있다. 본 연구의 목적은 통계기반 자동번역의 성능을 향상시키기 위해 기존 다른 언어쌍의 말뭉치와 SMT 자동번역 기술을 이용하여 대상이 되는 언어쌍의 SMT 병렬 말뭉치를 자동으로 확장하는 방법을 제안한다. 제안 방법은 서로 다른 언어 B와 C의 병렬 말뭉치를 얻기 위해, A와 B의 SMT 자동번역 시스템을 구축하고 기존의 A-C 말뭉치의 A를 SMT를 통해 B로 번역하여 B와 C의 말뭉치를 자동으로 확장한다. 실험을 통해 확장한 병렬 말뭉치가 통계기반 자동번역 시스템의 성능을 향상시킬 수 있음을 확인한다.

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Pivot-based Bilingual Lexicon Extraction Using Word2Vec and CCA (중간언어 기반의 Word2Vec와 CCA를 이용한 이중언어 사전 추출)

  • Kim, Jeong-Tae;Kim, Chang-Hyun;Cheon, Min-Ah;Kim, Jae-Hoon;Kim, Jae-Hwan
    • Annual Conference on Human and Language Technology
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    • 2016.10a
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    • pp.307-309
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    • 2016
  • 이중언어 사전은 자연어처리 분야에서 매우 유용한 자원으로 사용되고 있다. 그러나 초기사전이나 병렬말뭉치 등 자원이 부족한 언어 쌍에 대해서 이중언어 사전을 추출하는 것은 쉽지 않다. 이러한 문제를 해결하기 위해 본 논문에서는 중간 언어 기반으로 Word2Vec와 CCA를 이용하여 이중언어 사전을 추출하는 방법을 제안한다. 본 논문에서 제안하는 방법의 성능을 평가하기 위해서 중간언어로 영어를 사용하여 스페인어-한국어에 대한 이중언어 사전을 추출하는 실험을 하였다. 무작위로 뽑은 200개의 단어에 대한 번역 정확도를 구하였다. 그 결과 최상위에서 37.5%, 상위 10위에서 63%, 그리고 상위 20위에서는 69.5%의 정확도를 얻을 수 있었다.

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