• 한국해양공학회지
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• 제34권3호
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• pp.180-193
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• 2020

In this study, the end-effector tracking performance of a manipulator installed on a remotely operated vehicle (ROV) for autonomous underwater intervention is verified. The underwater manipulator is an ARM 7E MINI model produced by the ECA group, which consists of six joints and one gripper. Of the six joints of the manipulator, two are revolute joints and the other four are prismatic joints. Velocity control is used to control the manipulator with forward and inverse kinematics. When the manipulator approaches a target object, it is difficult for the ROV to maintain its position and posture, owing to various disturbances, such as the variation in both the center of mass and the reaction force resulting from the manipulator motion. Therefore, it is necessary to compensate for the influences and ensure the relative distance to the object. Simulations and experiments are performed to track the trajectory of a virtual object, and the tracking performance is verified from the results.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.113-118
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• 2005

Robots today have wider application fields than they ever have before. They need to work close to humans and fluid and compliable motions are expected of them. This requires redundant degrees of freedom for completing specific task. And conventional motion teaching method cannot be applied to redundant link structures. In this paper, the authors present a proficient, cost-effective and intuitive method for motion teaching. New software to apply this method to a humanoid is also presented. This new method utilizes current sensors to determine which joints to rotate. The experiment shown in this paper is a case of closed link where arms cannot move independently due to the restrictions in between the hands. After the input of several passing points of motion trajectory, the curve fitting is performed by the developed software. This software can insert new points, delete erroneous points and modify existing points. The developed motion teaching method is applied to the Kumdo robot, which is developed by the authors.

• 한국정밀공학회지
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• 제19권10호
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• pp.120-129
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• 2002

An integrated structure and controller design approach for rotating cantilever beam is presented. An optimization method is developed for improving positioning performance considering the elastic deformations during high speed rotation and adopting the beam shape and the control gains as design variables. For this end, a dynamic model is setup by the finite element method according to the shape of the beam. The mass and stiffness of the beam are distributed in such a way that the closed-loop poles of the control system should be located leftmost in the complex s-plane. For optimization method, the simulated annealing method is employed which has higher probability to find the global minimum than the gradient-based down-hill methods. Sequential design and simultaneous design methods are proposed to obtain the optimal shape and controller. Simulations are performed with new designs by the two methods to verify the effectiveness of the approach and the results show that the settling time is improved for point-to-point position controls.

• 한국수산과학회지
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• 제36권5호
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• pp.480-485
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• 2003

Morphology of the spermatozoa from the testes of the catfish (Pseudobagrus brevicorpus) was studied by transmission and scanning electron microscopy. The spermatozoa of P. brevicorpus are approximately $82.25\pm0.06\;{\mu}m$ in length and relatively simple cells composed of a spherical head, a short midpiece and a tail as in most teleost fish, The nucleus measuring about $2.00\pm0.02\;{\mu}m$ in length is depressed with a deep nuclear fossa of about $1.05\pm0.03\;{\mu}m$ in length three fifths of the nuclear length. The nuclear fossa contains the proximal and distal centrioles. The two centrioles are oriented approximately $150^{\circ}$ to each other. The mitochondria are arranged in two layers and their number is 12 or more. They are separated from the axoneme by the cytoplasmic canal. The axoneme is the 9+2 microtubular pattern and has inner but no outer dynein arms as in other bagrids. The axonemal fins were the closed to axonemal doublet 3 and 8. The axonemal fins and lost outer dynein arm are shared in Bagridae and the deep nuclear fossa is shared in Siluriformes. The axonemal fins observed in Bagridae and Amblycipitidae of Siluriformes might be the apomorphic character in Ostariophysi.

• International Journal of Aeronautical and Space Sciences
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• 제4권1호
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• pp.75-87
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• 2003

The primary objective of this study is to demonstrate ground-based experiment for the attitude control of spacecraft. A two-axis rotational simulator with a flexible ann is constructed with on-off air thrusters as actuators. The simulator is also equipped with payload pointing capability by simultaneous thruster and DC servo motor actuation. The azimuth angle is controlled by on-off thruster command while the payload elevation angle is controlled by a servo-motor. A thruster modulation technique PWM(Pulse Width Modulation) employing a time-optimal switching function plus integral error control is proposed. An optical camera is used for the purpose of pointing as well as on-board rate sensor calibration. Attitude control performance based upon the new closed-loop control law is demonstrated by ground experiment. The modified switching function turns out to be effective with improved pointing performance under external disturbance. The rate sensor calibration technique by Kalman Filter algorithm led to reduction of attitude error caused by the bias in the rate sensor output.

• Archives of Plastic Surgery
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• 제45권1호
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• pp.85-88
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• 2018

Local flaps exhibit excellent color matching that no other type of flap can compete with. Moreover, surgery using a local flap is easier and faster than surgery using a distant or free flap. However, local flaps can be much more difficult to design. We designed 2 templates to plan a V-Y rotation advancement flap. The template for a unilateral V-Y rotation advancement flap was used on the face (n=5), anterior tibia (n=1), posterior axilla (n=1), ischium (n=1), and trochanter (n=2). The template for a bilateral flap was used on the sacrum (n=8), arm (n=1), and anterior tibia (n=1). The causes of the defects were meningocele (n=3), a decubitus ulcer (n=5), pilonidal sinus (n=3), and skin tumor excision (n=10). The meningocele patients were younger than 8 days. The mean age of the adult patients was 50.4 years (range, 19-80 years). All the donor areas of the flaps were closed primarily. None of the patients experienced wound dehiscence or partial/total flap necrosis. The templates guided surgeons regarding the length and the placement of the incision for a V-Y rotation advancement flap according to the size of the wound. In addition, they could be used for the training of residents.

• Steel and Composite Structures
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• 제45권5호
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• pp.697-713
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• 2022

In the context of the finite elements method, the dynamic behavior of porous functionally graded double wishbone vehicle suspension structural system incorporating joints flexibility constraints under road bump excitation is studied and analyzed. The functionally graded material properties distribution through the thickness direction is simulated by the power law including the porosity effect. To explore the porosity effects, both classical and adopted porosity models are considered based on even porosity distribution pattern. The dynamic equations of motion are derived based on the Hamiltonian principle. Closed forms of the inertia and material stiffness components are derived. Based on the plane frame isoparametric Timoshenko beam element, the dynamic finite elements equations are developed incorporating joint flexibilities constraints. The Newmark's implicit direct integration methodology is utilized to obtain the transient vibration time response under road bump excitation. The presented procedure is validated by comparing the computational model results with the available numerical solutions and an excellent agreement is observed. Obtained results show that the decrease of porosity percentage and material graduation tends to decrease the deflection as well as the resulting stresses of the control arms thus improving the dynamic performance and increasing the service lifetime of the control arms.

• 대한한방부인과학회지
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• 제26권4호
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• pp.30-47
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• 2013

목 적: 본 연구는 만성 스트레스로 인한 갱년기 우울증 모델에서 사물탕가향부자(SGH)의 항우울 효과를 검증하여 실험적 유의성을 확인하고자 시행되었다. 방 법: 난소적출 흰쥐에 4주간 만성 스트레스를 가하고 SGH(100 and 400 mg/kg/day)를 투여한 후 행동검사인 sucrose intake test(SIT), elevated plus maze(EPM), forced swimming test(FST) 및 Morris water maze test(MWMT) 등을 통한 우울행동 변화와 혈청 corticosterone(CORT), IL-$1{\beta}$ 및 IL-4 등의 변화를 측정하였고, 또한 뇌 내 hippocampus와 hypothalamus에서 5-HT의 변화를 측정하였다. 결 과: 1. SIT에서 SGH 400 mg/kg/day 투여군은 대조군에 비해서 자당 섭취가 유의하게 증가하였다(p<0.05). 2. EPM에서 SGH 400 mg/kg/day 투여군은 대조군에 비해서 open arms에 머무는 시간이 유의하게 증가하였고(p<0.01), open arms와 closed arms를 교차하는 횟수도 대조군에 비해서 유의하게 증가하였다(p<0.05). 3. FST에서 SGH 100 mg/kg/day, 400 mg/kg/day 투여군 모두 대조군에 비해서 immobility시간이 유의하게 줄어들었다(SGH 100 p<0.05, SGH 400 p<0.01). 4. MWMT에서 SGH 100 mg/kg/day, 400 mg/kg/day 투여군은 모두 대조군에 비해서 실험 4일째에서 acquisition trials 수행 시간이 유의하게 단축되었고(p<0.05), SGH 400 mg/kg/day 투여군은 대조군에 비해서 retention trials 수행 시간이 유의하게 증가하였다(p<0.05). 5. CORT와 IL-4 측정에서 대조군과 SGH 투여군 모두 유의한 변화가 없었고, IL-$1{\beta}$ 측정에서 대조군에서는 유의하게 증가하였지만 SGH 투여군에서는 대조군에 비해서 유의한 변화가 없었다. 6. Hippocampus에서의 5-HT 측정에서 SGH 400 mg/kg/day 투여군은 대조군에 비해서 유의하게 증가하였다(p<0.05). Hypothalamus에서의 5-HT수준은 SGH 투여군 모두 대조군에 비해서 유의하게 증가하였다(SGH 100 p<0.05, SGH 400 p<0.01). 결 론: 이상의 결과로 SGH는 만성 스트레스를 가한 난소적출 흰쥐에서 항우울 효과가 있음을 알 수 있었고, HPA axis, immune system 보다 5-HT system에 작용하는 것으로 사료된다.

• 대한골관절종양학회지
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• 제9권1호
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• pp.1-11
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• 2003

목적: 전이암 혹은 악성 혈액질환에 의한 상완골의 병적골절의 비관혈적 고합성 골수강내 금속정 삽입술에 대한 임상적 및 방사선학적 결과를 분석하였다. 대상 및 방법: 전이암 혹은 다발성 골수종에 의한 상완골 병적골절 혹은 임박골절로 치료받은 29명중 비관혈적 정복 및 고합성 골수강내 금속정 고정술로 치료 받은 13명 16례를 대상으로 병적기록과 방사선 사진을 분석하였다. 통증 완화와 기능 회복의 평가는 Perez 등의 방법을 변형하여 우수, 양호, 보통, 불량으로 하였다. 결과: 원발암은 다발성 골수종 4명, 폐암 3명, 유방암 2명, 그 외에 선암(adenocarcinoma), 신장암, 위암 및 대장암이 각각 1명이었다. 2명에서는 상완골의 병적골절 후 원발암이 진단되었고, 11명에서는 원발암 진단 후 최소 1개월, 최장 10년, 평균 28.9개월에 상완골 병적골절이 발견되었다. 상완골로의 전이가 발견된 후 최단10주(신장암), 최장 4년 7개월(다발성 골수종), 평균 11.7개월간 생존하였다. 상완골 전이 16례중 13례에서 보통이상의 통증 완화와 기능회복을 보였으나, 수술 후 골 파괴가 진행되었거나 동측 수부로 전이한 3례에서는 불량한 결과를 보였다. 이들 3례와 수술 후 3개월 이전에 사망한 3례를 제외한 10례에서 골유합을 얻을 수 있었으며, 수술 후 감염, 신경마비 등 수술과 관계되는 합병증은 없었다. 결론: 전이암 혹은 악성 혈액질환에 의한 상완골 병적골절은 골절전의 기능상태, 원발암의 종류, 예상되는 생존기간, 환자의 전신상태, 전이암의 국소 및 전신 침범정도에 따라 수술방법을 달리해야 할 것으로 사료된다.

• 대한본초학회지
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• 제21권2호
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• pp.63-75
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• 2006

Objectives : We investigated the effects of Liriopis Tuber on the nervous protection. Methods : We measured the reaction behavior with EPM(Elevated Plus Maxe) and MWM(Morris Water Maze) after applying restraint stress to rats. Also, the degrees of AchE generation were measured with immunohistochemical method in the regions of hippocampus, and the degree of TH generation in the regions of VTA and LC, respectively. Results : 1. As the results of measuring how long EPM which reflects anxiety reaction stayed in the open arm, there was the trend which can suppress anxiety reaction in the MMD+stress group(Liriopis Tuber+stress) but no statistical significance. The counting results how many EPM passed between opened and closed arm showed suppression trend against a physical activity in the saline+stress group but there was no statistical significance. 2. According to the result of MWM, the saline+stress group showed the learning retardation which means increased time arriving at goal compared to ti1e normal group at the second and third day of measurement. On the contrary, a learning retardation was significantly decreased in the MMD+stress group. Among the probe trial test a memory loss occurred in the saline+stress group, meanwhile memory ability was notably increased in the saline-stress group. 3. The degree of TH generation was investigated at the VTA and LC respectively after test animals treated with drug. In the saline+stress group, TH-immunoreactive cells were significantly increased, and these stress-induced TH increases were suppressed in the saline+stress group at the VTA region. However, the saline+stress group did not show any significant difference. 4. the degree of AchE generation was investigated at the CA3 of hippocampus. The saline+stress group showed that AchE-immunoreactive cells were significantly decreased. Those stress-induced reductions of AchE cells were meaningfully recovered in the saline+stress group. Although the cells showed recovery trend in the region of CA1 of hippocampus, statistical significance was not observed. Conclusion : The results of our study indicate that Liriopis Tuber can improve spatial memory ability of rats applied a restraint stress. This improvement of the spatial memory ability is considered to have an efficacy of nervous protection that Liriopis Tuber suppresses the generation of AchE in the hippocampus region and enhances the generation of TH in the VTA.