• Title/Summary/Keyword: 링크의 변형 측정

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A Study on Passive Force Control of a Flexible Manipulator (유연 매니퓨레이터의 피동적인 힘 제어에 관한 연구)

  • Kim, Jin-Soo
    • Journal of the Korean Society for Precision Engineering
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    • v.16 no.10
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    • pp.209-216
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    • 1999
  • 일반적으로 힘 제어는 힘 센서의 사용 여부에 따라 능동적 힘 제어와 피동적 힘 제어로 분류시킬 수 있다. 능동적 힘 제어는 힘 세서를 이용하여 구속력을 목표한 힘에 근접하도록 제어한다. 유연 매니퓨레이터의 함수(위치, 속도, 가속도)를 이용하여 일정한 힘에 근접하도록 제어한다. 유연 매티퓨레이터에 있어서 링크 선단의 강성 증대는 힘 제어뿐만이 아니라, 링크의 진동을 크게 유발함으로서 위치 제어에 불리하게 작용한다. 주로 사용되고 있는 힘 센서는 많은 변형 게이지(strain gauge)로 구성되어 있다. 유연 매니퓨레이터 또한 링크 선단의 변형을 측정하기 위해 변형 게이지를 사용하고 있다. 본 논문에서는 이점에 착안하여, 유연 매니퓨레이터의 선단의 탄성 변형을 측정하기 위해 장착한 변형 게이지를 이용한 위치/힘 제어를 제안한다. 먼저, 유연 매니퓨레이터의 집중 정수 모델로부터 링크의 탄성 변형과 구속력 관계를 도출한 후 이 관계를 이용하여 3차원 실험 유연 매니퓨레이터를 실시간 위치/힘 제어 실험을 수행하였다. 또한 범용 동력학 해석 소프트웨어인 ADAMS FEM 을 이용하여 해석하였다. 마지막으로, 실험 결과와 해석 결과를 비교 분석하여 본 논문에서 제안한 유연 매니퓨레이터의 위치/힘 제어의 타당성을 입증시켰다.

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Spanning Tree Aggregation Using Attribute of Service Boundary Line (서비스경계라인 속성을 이용한 스패닝 트리 집단화)

  • Kwon, So-Ra;Jeon, Chang-Ho
    • The KIPS Transactions:PartC
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    • v.18C no.6
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    • pp.441-444
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    • 2011
  • In this study, we present a method for efficiently aggregating network state information. It is especially useful for aggregating links that have both delay and bandwidth in an asymmetric network. Proposed method reduces the information distortion of logical link by integration process after similar measure and grouping of logical links in multi-level topology transformation to reduce the space complexity. It is applied to transform the full mesh topology whose Service Boundary Line (SBL) serves as its logical link into a spanning tree topology. Simulation results show that aggregated information accuracy and query response accuracy are higher than that of other known method.

Triangle Betweenness Centrality in Weighted Directed Networks (가중 방향성 네트워크에서 삼각매개중심성의 측정 방법)

  • Jae Yun Lee
    • Journal of the Korean Society for information Management
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    • v.41 no.3
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    • pp.511-533
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    • 2024
  • This study aims to develop novel centrality measures applicable to networks that include both directional and weighted information, such as interlibrary loan networks and logistics transportation networks. While weighted PageRank has traditionally been used in such cases, experimental results reveal that it yields similar outcomes to neighborhood centrality, which measures local centrality. However, triangle betweenness centrality (TBC), despite assessing global centrality in weighted networks, does not consider link directions. To address these limitations, we propose two modified versions of the existing TBC measure: TBC-T for trust networks and TBC-F for flow networks. Applying these measures to two interlibrary loan networks, we find that TBC-T considers only the weights of inlinks, while TBC-F incorporates both inlink and outlink weights. These newly developed measures are expected to be useful for measuring node global centrality in weighted directed networks.

Analysis of Dynamic Deformation of 4-Bar Linkage Mechanism(II) (4절 링크 기구의 동적 변형 해석 (II))

  • 조선휘;박종근;주동인
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.16 no.5
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    • pp.910-923
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    • 1992
  • Experimental verification of numerical results is conducted by measuring the dynamic strains of mid-points of the coupler and the lever for the 4-bar linkage mechanism with rigid bearing and flexible bearing, respectively. For the axial strain of lever mid-point, the numerical results including geometric stiffness almost agree with the experimental ones, however, the numerical results excluding geometric stiffness almost agree with the experimental ones for the axial strain of coupler mid-point. It is supposed that these phenomena should be caused by the fact that the motion of the coupler is more complicated than of the lever. The signals of dynamic strains of coupler and lever mid-points, measured by strain gages, are transformed into frequency domain by fast fourier transformer. From this experiment, the lst resonance frequencies of the coupler and the lever are obtained. It is made clear that the former almost agrees with the fundamental and the latter the 2nd mode natural frequency of the mechanism system calculated by numerical analysis.

A Spam Mail Classification Using Link Structure Analysis (링크구조분석을 이용한 스팸메일 분류)

  • Rhee, Shin-Young;Khil, A-Ra;Kim, Myung-Won
    • Journal of KIISE:Software and Applications
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    • v.34 no.1
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    • pp.30-39
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    • 2007
  • The existing content-based spam mail filtering algorithms have difficulties in filtering spam mails when e-mails contain images but little text. In this thesis we propose an efficient spam mail classification algorithm that utilizes the link structure of e-mails. We compute the number of hyperlinks in an e-mail and the in-link frequencies of the web pages hyperlinked in the e-mail. Using these two features we classify spam mails and legitimate mails based on the decision tree trained for spam mail classification. We also suggest a hybrid system combining three different algorithms by majority voting: the link structure analysis algorithm, a modified link structure analysis algorithm, in which only the host part of the hyperlinked pages of an e-mail is used for link structure analysis, and the content-based method using SVM (support vector machines). The experimental results show that the link structure analysis algorithm slightly outperforms the existing content-based method with the accuracy of 94.8%. Moreover, the hybrid system achieves the accuracy of 97.0%, which is a significant performance improvement over the existing method.

Modified LEACH Protocol improving the Stabilization of Topology in Metal Obstacle Environment (금속 장애물 환경에서 토폴로지 안정성을 개선한 변형 LEACH 프로토콜)

  • Yi, Ki-One;Lee, Jae-Kee;Kwark, Gwang-Hoon
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.34 no.12B
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    • pp.1349-1358
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    • 2009
  • Because of the limitation of supporting power, the current WSN(Wireless Sensor Network) Technologies whose one of the core attributes is low power consumption are the best solution for shipping container networking in stack environment such as on vessel. So it is effective to use the Wireless Sensor Network Technology. In this case, many nodes join in the network through a sink node because there are difficulties to get big money and efforts to set up a lot of sink node. It needs clustering-based proactive protocol to manage many nodes. But it shows low reliability because they have effect on radio frequency in metal obstacle environments(interference, distortion, reflection, and etc) like the intelligent container. In this paper, we proposed an improved Modified LEACH Protocol for stableness radio frequency environment. In the proposed protocol, we tried to join the network and derived stable topology composition after the measuring of link quality. Finally, we verified that the proposed protocol is composing more stable topology than previously protocol in metal obstacle environment.

A Technique for Measuring the Self-Production of Internet Newspapers (인터넷 신문기사의 자체 생산량 측정 기술)

  • Kim, Dong-Joo;Kim, Han-Woo
    • Proceedings of the Korean Society of Computer Information Conference
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    • 2009.01a
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    • pp.445-449
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    • 2009
  • 인터넷의 발달과 인터넷 문화의 보편화로 인하여 사용자들은 폭발적으로 증가하는 다양한 정보를 접할 수 있게 되었으며, 자체 생산하거나 다른 신문사들로부터 생산된 기사들을 단순 유통, 링크를 통하여 정보검색 사이트들뿐만 아니라 각종 포털 사이트, 인터넷신문사들은 많은 다양한 경로로 기사를 제공할 수 있게 되었다. 이에 따라 인터넷산문을 규정하고 법적, 테두리에 넣기 위한 법률이 제정되었으며, 인터넷신문사에 대해 기사의 자체 생산량이라는 요건 검증에 대한 요구가 증가하고 있다. 본 논문은 인터넷신문 자체기사 생산량을 측정하기 위해 필요한 기술들을 조사하고 타당성을 검토하여 이에 적합한 기술을 제시한다. 제시한 방법은 대량의 기사의 비교를 빠른 시간에 수행한 수 있도록 하기 위해 인간의 단어 인지와 관련한 경험적 정보의 반영을 통하여 변형한 편집거리 기반 방법이다. 제시하는 방법의 정확성을 검증하기 위해 실제 소량의 인터넷 신문 기사를 대상으로 실험하였다.

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Development of Load Cell Using Fiber Brags Grating Sensors and Differential Method for Structural Health Monitoring (구조 건전성 모니터링을 위한 광섬유 브래그 격자 센서와 차동법을 적용한 로드셀 개발)

  • Kim, Dae-Hyun
    • Journal of the Korean Society for Nondestructive Testing
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    • v.29 no.4
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    • pp.299-307
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    • 2009
  • Emerging fiber optic sensor technologies have shown great potential to overcome the difficulties associated with conventional sensors. Fiber optic sensors are immune to EM noise and electric shock and thus can be used in explosion-prone areas. Several kinds of fiber optic sensors have been developed over the last two decades to take advantage of these merits. There have also been many field applications of fiber optic sensors for structural health monitoring as NDT/HDE. However, very few sensors, particularly a load cell have been successfully commercialized. This Paper Presents a load cell using fiber Bra99 gra1ing (FBG) sensors. The shape of the load cell is a link type, and three FBG sensors are used for measuring strains at three different points. Especially, these strains are processed with a differential method in order to exclude common mode noise such as temperature. Moreover, the sensitivity, the linearity and the resolution of the load cell were successfully verified from the experiment of tension test.

Design of a Modified Alford Loop Antenna for On-Body Devices (인체 부착형 기기를 고려한 변형된 Alford 루프 안테나 설계)

  • Park, Joongki;Lee, Juneseok;Choi, Jaehoon
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.25 no.1
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    • pp.25-31
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    • 2014
  • In this paper, a modified Alford loop antenna for on-body communication system is proposed. The proposed antenna operating in the ISM band is designed with consideration of human body effect. One of advantages of the Alford loop antenna structure is low-profile, however the Alford loop antenna is not suitable for on-body devices since it does not have a ground plane for other electronic part of on-body system and requires balanced feeding structure. To be embedded on on-body devices, the proposed antenna is design with the unbalanced feed structure and ground. The performance of the proposed antenna is simulated and measured when it is placed on the human body phantom to consider the effect of the human body. The proposed antenna a 10 dB return loss bandwidth over the ISM band and monopole-like radiation pattern with low-profile. The antenna has the surface of appropriate for on-body communication environment.

Design and Optimization of Active Transfemoral Prosthesis System (능동형 대퇴의지 시스템의 설계 및 최적화 연구)

  • Chung, J.H.;Lee, K.H.;Lee, C.H.
    • Journal of rehabilitation welfare engineering & assistive technology
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    • v.8 no.4
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    • pp.283-289
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    • 2014
  • This paper presents a design and optimization of the fully-active transfemoral prosthesis leg system. As it has one degree of freedom in knee joint, this prosthesis leg can imitate the human's gait. The weight of system, which makes the users more comfortable due to less tiredness, and the knee joint torque to rise stability of the system are major factors of prosthesis leg system. Thus the mechanism of prosthesis changes from 3-linkage type to geared type. The sensorized foot is also designed to effectively determine human's gait by measuring deformation of the foot during gait. Topology optimization is carried out for the sensorized foot to remove its unnecessary weight. The safety of optimized foot is verified by carrying out finite element analysis.

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