• 한국운동역학회지
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• 제15권4호
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• pp.43-53
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• 2005

This study is to define how the difference of athletic change influence on the last regrasp after somersault in Belle movement of parallel bars. For his study, the following conclusion was produced by analysis of athletic change by means of three dimensional visual image in three athlete of nation. 1. As the picture of S1, there are total used time(2.01 sec), S3(2.17 sec) and S2(2.19 sec). In case of a short needed time, it is difficult for them to perform the remaining movement of the vertical elevating flight easily and comfortably, it is judged as performing the small movement with restrict swing. 2 In the change of body center sped by each event, it is calculated as $-89.1^{\circ}$ the narrowest in S1, $-81.96^{\circ}$ the widest and then $86.34^{\circ}$ in S3. In E3 event, average compound speed is 4.07m/s, S2 showed the fastest speed of 4.14m/s whereas S1 the narrowest angle of 3.95m/s. 3. A shoulder joint and coxa are the period of mention in E3. In E4 which was pointed out the longest vertical distance, S2 that is indicated the highest vertical height as the period of detach in parallel bars. showed -3.91m. This is regarded as a preparatory movement for dynamic performance after using effectively elastic movement of shoulder joint and coxa while easily going up with turning back movement. In the 5th phrase, long airborne time and vertical change position is showed as the start while regrasping securely air flight movement from high position. 4. In E5, a long flight time and a long vertical displacement were shown as the regrasp after somersault efficiently in high position with stability from the point of the highest peak of the center of the body. Especially, S2 is marked as a little bit long position, while S1 is reversely indicated as performing somersault and unstable motion in a low position. 5. In E3, at the point of the largest extension of the shoulder joint and hip joint the shoulder joint is largely marked in $182^{\circ}$ and the hip point $182^{\circ}$ in S2. The shoulder joint is marked at the smallest angle in $177^{\circ}$ and the hip point $176^{\circ}$ in S1. And S1 is being judged by its performance of the less self - confident motion with lessening a breath of swing. S2 makes the most use of flexion and extension of the shoulder joint and the hip joint effectively. It was performed greatly with swinging and dropping the rotary movement and the rotary inertia naturally. 6. In E6, as the point of regrasp of the upper arm in parallel bars it is recognized by the that of components of vertical and horizontal velocity stably. During this study, the insufficient thing and the study on the parallel bars at a real game later are more activated than now. If it is really used as the basic materials by means of Belle Picked Study of Super E level after Bell movement, you may perceive the technique movement previously and perform without difficulty. Especially, such technique as crucifix is quite advantageous for oriental people thanks to small body shape condition. In conclusion we will nicely prepare for our suitable environment to gradually lessen trials and errors by analyzing and studying kinematically this movement.

• 한국CDE학회논문집
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• 제6권2호
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• pp.69-77
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• 2001

This paper describes a method of calculating the feedrate for the constant cutting speed at a CL-point in 5-axis machining. Unlike 3-axis machining, 5-axis machining has the flexibility of the tool motions due to two rotation axes. But the feedrate at joint space differs from the feedrate at a tool tip(the CL-point) of the 3D Euclidean space for the tool motions. The proposed algorithm adjusts the feedrate based on 5-axis NC data, the kinematics of a machine, and the tool length. The following calculations is processed for each NC block to generate the new feedrate; 1) calculating the moving distance at the CL-point, 2) calculating the moving time by the given feedrate, 3) calculating the feedrate of each axis, 4) getting the new feedrate. The proposed algorithm was applied to a 5-axis machine which had a tilting spindle and a rotary table. Totally, the result of the algorithm reduced the machining time and smoothed the cutting-load by the constant cutting speed at the CL-point.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 추계 학술발표회
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• pp.1289-1293
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• 2010

A slipring or FORJ are usually adopted in order for power supply of Geo-centrifuge and input/output data acquisition. Since using slipring causes quite a lot electrical noise, an optical communication using FORJ becomes more general for data acquisition. Such data acquisition devices, however, require frequent maintenance and replacement due to deterioration by long term usage. DICT has set up a real-time wireless date acquisition system using wireless communication technology instead of FORJ. The system enables a remote measurement at any inertial acceleration field up to 100g level and provides as same performance as FORJ. The priority of this system is to use a normal modem substituting a special FORJ.

• 조명전기설비학회논문지
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• 제27권8호
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• pp.75-82
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• 2013

We propose a fiber grating sensor system for condition monitoring of large scale wind turbine blades. For the feasibility test of the proposed sensor system, a down-scaled wind turbine has been constructed and experimented. Fiber grating sensors were attached on a blade surface for distributed strain and temperature measurements. An optical rotary joint was used to transmit optical signals between the FBG sensor array and the signal processing unit. Instead of broadband light source, we used a wavelength-swept fiber laser to obtain high output power density. A spectrometer demodulation is used to alleviate the nonlinear wavelength tuning problem of the laser source. With the proposed sensor system we could measure dynamic strain and temperature profiles at multi-positions of rotating wind turbine blades.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2006년도 춘계학술대회 논문집
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• pp.353-358
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• 2006

A three-dimensional finite element approach to process analysis and design for joining the socket with the ball by a kind of the rotary forging processes is presented in this paper. The rigid-plastic finite element method is employed and its results are used to reduce the number of process design tryouts. The approach is applied to developing a concave piston assembly for a high pressure hydraulic pump. Experiments show that the developed piston assembly satisfies the quality requirement on geometrical tolerance.

• 천문학회보
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• 제37권2호
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• pp.217.2-217.2
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• 2012

저궤도위성 관제용 소형안테나시스템의 송수신채널은 저궤도위성의 특성상 안테나구동부의 물리적인 제약조건을 갖으며 이러한 제약조건은 Rotary Joint 포트 수에 의존한다. 다목적 실용위성 5호와 같이 RH 및 LH 편파를 동시 사용하는 위성의 경우 지상안테나의 RF채널은 물리적으로 4포트가 필요하게 된다. 이러한 물리적 채널을 구현하기위해서는 안테나구동부가 대형화될 뿐만 아니라 고비용의 소요된다. 이와 같이 대형화 및 고비용의 단점을 극복하기위하여 Channel Combine Filter를 적용하여 채널이중화를 구현하였으며 단일채널을 갖는 저궤도위성 지상안테나시스템을 RH 및 LH 편파를 동시수신 가능하도록 성능을 개선하였다. 금번 개발된 Channel Combiner는 하나의 물리적 채널을 이용하여 위성으로부터 수신되는 수신신호 및 지상에서 송신하는 송신신호를 동시에 전송하도록 설계한 것으로서 수신되는 신호대비 송신신호의 크기가 상대적으로 고출력이기 때문에 송수신신호간의 간섭영향을 최소화할 수 있도록 설계하였다. 따라서 본 논문에서는 채널이중화를 위하여 개발된 Channel Combiner의 설계방법 및 성능 시험결과에 대하여 상세하게 기술하였으며, 최종적으로 RH 및 LH 편파를 동시에 사용하는 저궤도 위성을 이용한 수신결과에 대하여 기술하였다.

• 대한조선학회논문집
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• 제37권2호
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• pp.118-126
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• 2000

용접이음재에서는 용착금속, 열영항부 및 모재가 열사이클 및 조직의 변화에 의하여 각종 기계적 성질의 차이가 있으며, 특히 부식환경에서는 이들의 영향이 현저하게 나타나는 경우가 많다. 또 용접이음재의 피로강도는 이음형식, 용접금속 및 열영향부의 특성, 사용환경과 응력의 종류에 따라 변화한다. 따라서 본 연구에서는 현재 선박 및 해양구조물의 건조에 많이 채용되고 있는 TMCP 강재의 $CO_2$ 가스 용접이음재의 열영향부에 대한 대기중 및 부식환경중에서의 회전굽힘피로시험을 실시하여 피로균열의 발생 및 성장거동을 조사 검토하였다. 또한 대기중의 피로강도와 부식환경중의 피로강도를 비교함으로써 부식효과 및 응력집중효과 등을 고려한 용접이음재의 부식환경중에서의 피로강도 평가법 및 피로강도 설계곡선을 검토하였다.

• 한국운동역학회지
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• 제16권3호
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• pp.173-181
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• 2006

The purpose of this study is grasp the problem of the gymnast, Kim, Dong-Hwa's Kip to Swallow Motion in Rings, and make up for the weak points to help him to perform a better performance. Therefore, two tryouts for $28^{th}$ Athens Olympic Games were filmed using video camera then finalized with Kinematical Analysis using 3D motion analysis program followings are the form of conclusions. 1. In the very first tryout, when he was doing a Swallow Support Scale, his CM position was high and arm slope was deduction because when he was doing Kip, the ascent velocity was low and he tried excessively to pull him on rings due to relying upon angular movement of shoulder joint. 2. When he was doing drop, he let his hip angle bend only little bit and let fall so making shoulder angle wider and maintain the level horizontally occurs strong drop motion when vertical descent is happening. 3. As a result, lowering the direction of a kick makes CM's movement path lower, increase vertical ascent velocity, and it helps to do the Swallow Support motion in short period of time. 4. After a strong drop motion, which is deep and fast, would make rope of ring shake so there is a defect that the body moves to forward area. However, it does not effect in Swallow Support Scale motion. 5. In the second tryout, trunk rotation angle and arm slope was fixed decrease while doing rotary motion. When rotary motion was happening, before the body was going under the rings, maintained his arm slope horizontally so his Swallow Support Scale motion was nearly perfect.

• 대한관절경학회지
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• 제5권2호
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• pp.135-139
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• 2001

목적 : 진구성 후방, 후외측 또는 후내측 회전 불안정성에 대한 수술시 후방 관절막 파열을 발견할 수는 있으나 이에 관한 관절경적 치료 방법에 대한 보고는 아직 없다. 저자들은 후내측 또는 후외측 관절막 파열을 후방 경격막 도달법을 이용한 새로운 관절경적 봉합술을 소개하고자 한다. 대상 및 방법 : 슬관절의 관절경적 기본검사 후, 후내측 도달법과 후외측 도달법을 개설하여 후방 경격막 도달법을 확보한 후 관절경적 시야 하에서 봉합용 갈고리를 이용하여 파열된 후내측 또는 후외 측 관절막을 봉합한다. 결론 : 후방 십자인대 재건술 또는 후외측 회전 불안정성에 대한 재건술시, 후내측 또는 후외측 관절막 파열을 후방 경격막 도달법을 이용한 관절경적 봉합술은, 충분한 시야 확보로 파열된 관절막을 정확히 봉합할 수 있었으며 불안정성을 현저히 감소시킬 수 있어 보다 우수한 수기로 판단된다.

• 한국군사과학기술학회지
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• 제16권5호
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• pp.653-658
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• 2013

For towing the new type armored vehicle and maintaining the close support, the armored recovery vehicle(ARV) with winch and crane has been developed. In case of crane, it is mainly used to salvage heavy objects by rotational and vertical motion. Especially, the crane bracket is very important parts due to fixing the ARV's body and rotary joint and preventing the force rotation of crane. Therefore, the crane bracket needs to have an enough strength to endure the high load and it is very important to analyze the stress distribution under loads. In the present work, the experimental and analytical investigation on structural integrity evaluation of crane bracket were carried out. The simulation of three-dimensional finite element method(FEM) was compared with experimental datum. From the numerical results, the FEM simulations corresponded well with th experimental results and the structural safety was confirmed by safety factor.