• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.1513-1518
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• 1996

A force reflecting hand controller can be used to provide more realistic information to the operator of a teleoperation system such as kinesthetic feedback from a slave robot. In this paper, a new design concept of a force reflecting 6-DOF hand controller utilizing the kinematic structure of a Stewart Platform is presented. Based on the optimal design technique of a Stewart Platform, a force reflecting hand controller has been designed and constructed to verify the technical feasibility of proposed design concept. In order to provide an operator with kinesthetic feedback information, a force mapping algorithm based on a reciprocal product of screws has been introduced. Finally, the technical feasibility of the design concept has been demonstrated through some of experimental results of the device under virtual environment on a real-time graphic system.

• Journal of Electrical Engineering and Technology
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• 제10권3호
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• pp.1349-1355
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• 2015

It is difficult to calculate the magnetic force of an object of magnetic material in contact with other objects using the existing methods, such as Maxwell stress tensor method, magnetic charge method, or magnetizing current method. These methods are applicable for force computation only when the object is surrounded by air. The virtual air-gap concept has been proposed for calculating the contact force. However, its application is limited to magneto-static system. In this paper, we present the virtual air-gap concept for contact surface force in the eddy-current system. Its validity and usefulness are shown by comparison between numerical and experimental examples.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 1999년도 춘계 학술발표회 논문집 Proceedings of EESK Conference-Spring
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• pp.161-168
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• 1999

The concept of seismic design was induced in our country which was poor in it for the scarcity of recognition and insufficiency of funds. Recently many specialists are enforcing the provisions of seismic design. But because seismic force of seismic design is very great and all the seismic force are concentrated on the fixed bearings and substructure the bearings are the seismic force are concentrated on the fixed bearings and substructure the bearings are destroyed so that seismic design lose its basic concept. In addition when the earthquake which exceeds seismic design force takes place the bridge is collapsed. For these reasons the developed seismic isolation design concept was appeared which diminishes seismic force itself by period shift and additional damping distributes it to each superstructures evenly. Therefore this study introduced the method which combines PC-LEADeR(design program for L.R.B) with SAP 2000(linear elastic analysis) and performs the seismic isolation design more elaborately and simply verified the propriety of that method and examined the force control of L. R. B.

• 전기학회논문지
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• 제58권2호
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• pp.278-284
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• 2009

The global force and interaction body force density were evaluated in permanent magnets by using the virtual air-gap scheme incorporating the finite-element method. Until now, the virtual air-gap concept has been successfully applied to calculate a contact force and a body force density in soft magnetic materials. These force calculating methods have been called as generalized methods such as the generalized magnetic charge force density method, the generalized magnetizing current force density method, and the generalized Kelvin force density method. For permanent magnets, however, there have been few research works on a contact force and a force density field. Unlike the conventional force calculating methods resulting in surface force densities, the generalized methods are novel methods of evaluating body force density. These generalized methods yield the actual total force, but their distributions have an irregularity, which seems to be random distributions of body force density. Inside permanent magnets, however, a smooth pattern was obtained in the interaction body force density, which represents the interacting force field among magnetic materials. To evaluate the interaction body force density, the intrinsic force density should be withdrawn from the total force density. Several analysis models with permanent magnets were tested to verify the proposed methods evaluating the interaction body force density and the contact force, in which the permanent magnet contacts with a soft magnetic material.

• 소성∙가공
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• 제10권6호
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• pp.449-456
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• 2001

The concept of stress wave was introduced through the quantized kinetic energy which is related to the potentional energy change of atom, molecular bond energy. Differentiated molecular bond energy $\varphi$() by the lst order displacement u becomes force F(F = d$\varphi$($u_i$)/du), if resversely stated, causing physically atomic displacement $u_i$. Such physical phenomena lead stress(force/area of applied force) can be expressed by wave equation of linearly quantized physical property. Through the stress wave concept, formation of dislocation, which could not explained easily from a theory of continuum mechanics, can be explained. Moreover, this linearly quantized stress wave equation with a stress concept for grains in a crystalline solid was applied to three typical metallic microstructures and a simple shape. The result appears to be a product from well treated equations of a quantized stress wave. From this result, it can be expected to answer the reason why the defect free and very fine diameters of long crystalline shapes exhibit ideal tensile strength of materials.

• Structural Engineering and Mechanics
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• 제3권5호
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• pp.475-495
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• 1995

In the past, physical models have been proposed, in compliance with the concept of the compressive-force path, for the realistic design of various statically determinate structural concrete members. The present work extends these models so as to encompass indeterminate RC structural forms. Pilot tests conducted on continuous beams and fixed-ended portal frames have revealed that designing such members to present-day concepts may lead to brittle types of failure. On the other hand, similar members designed on the basis of the proposed physical models attained very ductile failures. It appears that, unlike current design approaches, the compressive-force path concept is capable of identifying those areas where failure is most likely to be triggered, and ensures better load redistribution, thus improving ductility. The beneficial effect of proper detailing at the point of contraflexure in an indeterminate RC member is to be noted.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 추계학술대회논문집
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• pp.249-255
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• 2000

The design and test of an magnetostrictive linear motor(MLM) that operates based on self-moving cell concept is presented. The moving cell is composed of Terfenol-D linear actuator and a ring structure, and a cell train is constructed by connecting two cells in series. Since this motor uses the stroke of Terfenol-D actuators and friction force of the cells, it can essentially produce long stroke and large force. The overall performance of the MLM was measured in terms of speed and force. The pushing force is directly related with the friction force. This work is a proof-of-concept stage and investigation is necessary for realistic application.

• 한국국방경영분석학회지
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• 제36권2호
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• pp.39-52
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• 2010

미 국방성은 플랫폼중심전의 상향식소요제기에서 네트워크중심전의 하향식소요제기로 변화하고 능력기반전력구조개발에 힘쓰고 있으며, 한국군도 다변화하는 안보위협과 전시작전권전환을 앞두고 능력기반전력구조로의 전환을 시도하고 있으나 통합능력의 개념과 개발방법이 부족한 상태이다. 따라서 이 연구는 능력기반전력구조 개발을 위해 상 하위 조직 전체의 능력과 현재의 전력운용관점과 미래의 전력개발관점을 동시에 포함하는 통합능력프레임워크를 제시한다.

• Strategy21
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• 통권37호
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• pp.65-103
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• 2015

This study is an attempt to look into the future role of the ROKN and to provide a strategic way forward with a special focus on naval strategic concept and force planning. To accomplish this goal, this research takes four sequential steps for analysis: 1) assessing the role and utility of naval power of ROKN since its foundation back in 1945; 2) forecasting features of various maritime threats to influence the security of Korea in the future directly or indirectly; 3) identifying the roles to be undertaken by future ROKN; and 4) recommending Korean way of naval force planning and the operational concept of naval power. This study seeks to show that ROKN needs comprehensive role to better serve the nation with respect to national security, national prosperity and development, and future battle-space management. To safeguard the national security of Korea, it suggests three roles: 1) national guard for the peaceful unification; 2) protector of the maritime sovereignty; and 3) suppressor to maritime threats. Three more roles are highlighted for national prosperity: 1) escort of the national economy; 2) guardian for national maritime activities; and 3) contributor to the world peace. These roles need to be closely connected with the role for the battle-space management. This paper addresses the need for a dramatic shift of the central operational domain from land to maritime in the future. This will eventually offer future ROKN a leading role for developing strategic concept and force planning rather than merely a supporting one. This study finally suggests 'balanced' strategy both in concept development and force planning. A balanced force planning is a 'must' rather than an 'option' when considering a division of function between Task Fleets and Area Fleets, constructing cutting-edge conventional forces such as Aegis destroyer, CVs, or submarines, and the mix of high-profile platform and low-profile when composing future fleets. A 'balance' is also needed in operational concept. The fleet should be prepared to fulfill its missions based on two different types of force operation i.e., coercive or cooperative application of the utility of naval force. The findings and recommendations of the study are relevant today, and will be increasingly important in the future to achieve various political goals required by enhancing the utility of naval power.

• 한국과학교육학회지
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• 제36권3호
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• pp.423-434
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• 2016

이 연구의 목적은 연구자가 개발한 전향력 실험 장치를 통해 예비 지구과학 교사들이 가진 정신모형의 변화를 알아보는 것이다. 예비 지구과학 교사 5명을 대상으로 전향력에 대하여 질문지에 제시된 그림 그리기와 면담을 통해 전향력 실험 장치를 활용한 활동을 수행하기 전과 후의 정신모형을 조사하고 그 변화를 비교하였다. 정신모형 수준이 낮은 단계인 소박한 정신모형이었던 두 학생은 개발된 전향력 실험 장치를 통한 활동을 통해 정적 불안정 모형과 동적 불안정 모형으로 향상되었다. 그리고 활동 전 정적 불안정 모형을 보여주었던 두 학생은 활동 후 모두 동적 불안정 모형으로 변화하였다. 마지막으로 활동 전 동적 불안정 모형을 보여주었던 학생은 활동 후에도 동적 불안정 모형에 남아있었지만 이미 가지고 있었던 선개념이 과학적 개념으로 많이 변화한 모습을 보여주었다. 이 연구를 통해 개발된 전향력 실험 장치 활용이 학생들의 전향력 개념의 학습에서 안정적이고 과학적인 개념 형성에 효과적이었음을 확인할 수 있었다. 개발된 전향력 실험 장치가 학교 현장에서 전향력과 관련된 수업에 효과적으로 사용될 필요가 있으며 나아가 위의 예비 지구과학 교사들이 교사가 되어 학교 현장에서 학생들을 가르치는 동안 나타나는 정신모형의 변화에 대해서도 알아볼 필요가 있다.