• Title/Summary/Keyword: interest force

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The New Challenges for the Republic of Korea Navy and the Development of Maritime Task Flotilla's Force Development (한국해군의 새로운 도전과 기동전단의 발전 방향)

  • Kim, Duk-ki
    • Strategy21
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    • s.39
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    • pp.163-197
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    • 2016
  • The completion of Jeju Naval Base on February 2016 made the Republic of Korea Navy(ROKN) review the size and role of the Maritime Task Flotilla(MTF). The new strategic environment for the 12st century and the new challenges require the Navy to counter North Korea's provocations and prevent potential enemy's threat. The Navy is also required to take part in the variety of international roles and missions commensurated with Korea's global status to maximize the national interest. Despite these changes, Korea's military construction concept is still unable to break away from the old paradigm of the North Korean threat largely centered. In order to develop the current MTF into the Task Group with the construction of Jeju Naval Base, the Navy must newly not only establish new force development plan and fleet management concepts but also go to persuade and convince policy decision makers. To this end, the following efforts should be promoted. First, the ROK Navy steps up efforts in order to share with the Task Group's vision and strategy. The Navy should also provide the size and structure as well as the missions and roles of the Task Group to react to new maritime security environment. Second, the Navy analyse the MTF's ability and what is required and necessary to perform its duty. After that, it must set out the direction of the Task Group's force development. Third, the current missions and roles of the MTF should be re-established to respond various threats. Finally, accommodating of new technology to the MTF should intensify its strengths. The ROK Navy has a mixed force structure consisting of three fixed- base fleets and a MTF. The fixed base fleet has a passive force to defend and protect its own sea areas, but the MTF should actively not only counter North Korea's threats, including ballistic missiles, but also fight potential threats and takes international missions as a primary task force. However, the MTF has a limited capability to accomplish given missions and long-range operations, and thus, the ROK Navy is strongly required to construct the Task Group.

Electromagnetic Force Calculation Using Magnetic Vector Potentials in 3-D Problems (자기벡터포텐셜을 이용한 3차원 전자력 계산)

  • 양재진;이복용;이기식
    • Journal of the Korean Magnetics Society
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    • v.6 no.2
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    • pp.106-111
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    • 1996
  • Electric machines such as motors which have rmving parts are designed for producing mechanical force or torque. The accurate calculations of electromagnetic force and torque are important in the design these machines. Electromagnetic force calculation method using the results of Finite Element Method(FEM) has been presented variously in 2-D problems. Typically the Maxwell's Stress Tensor method and the method of virtual work are used. The former calculates forces by integrating the surface force densities which can be expressed in terms of Maxwell Stress Tensor(MST), and the latter by differentiating the electromagnetic energy with respect to the virtual dis¬placement of rigid bodies of interest. In the problems including current source, magnetic vector potentials(MVP) have rmstly been used as unknown variables for field analysis by a numerical method; e. g. FEM. This paper, thus, introduces the two both methods using MVP in 3-D case. To verify the usefulness of presented methods, a solenoid model is chosen and analyzed by 3-D and axisymmetric FEM. It is found that the force calculation results are in good agreement for several mesh schemes.

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A Study on the Public Interest Role of the Detective Industry for Music Copyright Protection (음악저작권 보호를 위한 탐정산업의 공익적 역할 연구)

  • Kim Mi Ok;Yun Sou Bin;Yeom Keon Ryeong
    • Industry Promotion Research
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    • v.8 no.1
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    • pp.23-33
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    • 2023
  • In modern times, damage caused by the spread of the Internet has become very diverse. In particular, due to the craze of K-pop since 2008, the damage caused by copyright infringement in the domestic and international music markets has become the biggest problem in the Internet market. However, the manpower of the police and copyright protection agencies to solve these increasingly intelligent crimes is insufficient. Therefore, we are trying to find out the role of the public interest detective as a supplementary force for the public authority and as a substitute for the copyright protection agency that can provide legitimate help for victims in the prevention of music copyright infringement and disputes. For this study, first, the concept and types of music copyright, the concept of public interest detectives, the current status and system of music copyright were identified, and the role of detectives for music copyright protection was explored through system operation and status analysis of protection agencies and literature review. Through the results of this study, it is hoped that the role of a professional detective in the public interest dimension of music copyright protection can be a good soil for the development of the detective industry in the future.

A study on the Design of Bidirectional Actuator using NITINOL (NITINOL을 이용한 차동식 액츄에이터의 설계에 관한 연구)

  • 정상화;김현욱;신형성;차경래;신병수
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2002.04a
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    • pp.670-674
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    • 2002
  • In the recent years, as the research and the development of micro and precision machinery become active, the interest of micro actuators using SMA(Shape Memory Alloy) has been increased. The dynamic characteristic analysis of SMA is necessary for actuator application and many common researches report the material characteristics of SMA sufficiently. However, the research on dynamic characteristics is very deficient. In this paper, the helical spring are fabricated with NiTi SMA wire of high resistivity. The force, response speed, temperature, and displacement are measured by digital force gauge, infrared thermometer, and laser displacement sensor so that the dynamic characteristics of this SMA is analyzed. Also, bidirectional actuator was fabricated and experimented for its performance.

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A study on the Improvement of the Performance of Bidirectional SMA Actuator (차동식 형상기억합금 액츄에이터의 동작성능향상을 위한 연구)

  • 정상화;김현욱
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2004.04a
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    • pp.155-159
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    • 2004
  • In the recent years, as the research and the development of micro and precision machinery become active, the interest of micro actuators using SMA(Shape Memory Alloy) has been increased. The dydnamic characteristic analysis of SMA is necessary for actuator application and many common researches report the material characteristics of SMA sufficiently. However the research for dynamic characteristics is very deficient. In this paper, the helical suing are fabricated with NiTi SMA wire of high resistivity. The force, response speed, temperature, and displacement are measured by digital force gauge, infrared thermometer, and laser displacement sensor so that the dynamic characteristics of this SMA is analyzed. Also, bidicrectional actuator was fabricated and experimented for its performance.

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Experimental Study on the Stiffness and Damping Coefficients of a Tilting Pad Journal Bearing (틸팅패드 저널베어링의 유막 강성 및 감쇠계수에 대한 실험적 연구)

  • Ha, Hyun-Cheon;Yang, Seong-Heon
    • The KSFM Journal of Fluid Machinery
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    • v.2 no.2 s.3
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    • pp.32-38
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    • 1999
  • An experimental study is performed to investigate the frequency effects of the excitation force on the linear stiffness and damping coefficients of a LOP (load on pad) type five-pad tilting pad journal bearing with the diameter of 300.91 mm and the length of 149.80 mm. The main parameter of interest in the present work is excitation frequency to shake the test bearing. The excitation frequency is controlled independently, using orthogonally mounted hydraulic exciters. The relative movement between the bearing and shaft, and the acceleration of the bearing casing are measured as a function of excitation frequency using the different values of bearing load and shaft speed. Measurements show that the variation of excitation frequency has quite a little effect on both stiffness and damping coefficients. Both direct stiffness and damping coefficients in the direction of bearing load decrease by the increase of shaft speed, but increase with the bearing load.

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Experimental Study on the Stiffness and Damping Coefficients of a Tilting Pad Journal Bearing (틸팅패드 저어널 베어링의 유막 강성 및 감쇠 계수에 대한 실험적 연구)

  • Ha, Hynn Cheon;Yang, Seong Heon
    • 유체기계공업학회:학술대회논문집
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    • 1998.12a
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    • pp.173-179
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    • 1998
  • An experimental study is performed to investigate the frequency effects of the excitation force on the linear stiffness and damping coefficients of a LOP (load on pad) type five-pad tilting pad journal bearing with the diameter of 300.91 mm and the length of 149.80 mm. The main parameter of interest in the present work is excitation frequency to shake the test bearing. The excitation frequency is controlled independently, using orthogonally mounted hydraulic exciters. The relative movement between the bearing and shaft, and the acceleration of the bearing casing are measured as a function of excitation frequency using the different values of bearing load and shaft speed. Measurements show that the variation of excitation frequency has quite a little effect on both stiffness and damping coefficients. Both direct stiffness and damping coefficients in the direction of bearing load decrease by the increase of shaft speed, but increase with the bearing load.

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A study on Bidirectional NiTi-Shape Memory Alloy Actuator (차동식 NiTi-형상기억합금 액츄에이터의 동특성연구)

  • 정상화;김현욱;장우양;김경석;신현성;차경래;나윤철
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2001.10a
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    • pp.75-79
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    • 2001
  • In the recent years, as the research and the development of micro and precision machinery become active, the interest of micro actuators using SMA(Shape Memory Alloy) has been increased. The dynamic characteristic analysis of SMA is necessary for actuator application and many common researches report the material characteristics of SMA sufficiently. However, the research on dynamic characteristics is very deficient. In this paper, the helical spring are fabricated with NiTi SMA wire of high resistivity, The force, response speed, temperature, and displacement are measured by digital force gauge, infrared thermometer, and laser displacement sensor so that the dynamic characteristics of this SMA is analyzed. Also, bidirectional actuator was fabricated and experimented for its performance.

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Design and Analysis of Square Beam Type Piezoelectric Vibrating Gyroscope (압전세라믹을 이용한 사각보형 진동자이로의 설계 및 성능분석)

  • 이정훈;박연규;이종원
    • Journal of KSNVE
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    • v.5 no.3
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    • pp.403-411
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    • 1995
  • Square beam type piezoelectric vibrating gyro is developed for the measurement of angular velocity, which is compact, small in size and mass- producible. It features that three pieces of piezoelectric ceramics and bonded onto one face of equilateral square bar type gyro head. Two of them are used as sentuators which drive the gyro head and measure Coriolis force. The third piece is used for the feedback signal in order to resonate the gyro head and measure Coriolis force. The third piece is used for the feedback signal in order to resonate the gyro head with its fundamental natural frequency. Matching two fundamental natural frequencies in the gyro head with its driving frequency is found critical in the design of vibration gyro. Calibration results show that the vibrating gyro developed has the dynamic characteristics of first-order system within the frequency range of interest, which can be easily compensated by a lead compensator.

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A Study on the Economic Activities of Marginal Labor Force (한계노동력 경제활동참가 형태에 대한 연구)

  • Yun, Heesuk
    • KDI Journal of Economic Policy
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    • v.27 no.2
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    • pp.155-203
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    • 2005
  • This paper intends to provide information about whichgroups should receive particular attention from policies aimed at raising participation and employment. A detailed portrait of the diversity of non-employment is presented with description of the extent the under-represented groups stayed in situations of labor inactivity. Also, once in employment, how these groups move from one sector to another is a main interest in the analysis. Using longitudinal data (1998-2002) constructed from 'the economically active population survey', I followed individuals over a five-year period and analyzed how frequently inactive persons enter the labor market and how they change industries and statuses.

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