• Nuclear Engineering and Technology
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• 제56권2호
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• pp.498-505
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• 2024

In this paper, a cable-driven endoscopic manipulator (CEM) is designed for the Chinese latest compact fusion reactor. The whole CEM arm is more than 3000 mm long and includes end vision tools, an endoscopic manipulator/control system, a feeding system, a drag chain system, support systems, a neutron shield door, etc. It can cover a range of ±45° of the vacuum chamber by working in a wrap-around mode, etc., to meet the need for observation at any position and angle. By placing all drive motors in the end drive box via a cable drive, cooling, and radiation protection of the entire robot can be facilitated. To address the CEM motion control problem, a discrete trajectory tracking method is proposed. By restricting each joint of the CEM to the target curve through segmental fitting, the trajectory tracking control is completed. To avoid the joint rotation angle overrun, a joint limit rotation angle optimization method is proposed based on the equivalent rod length principle. Finally, the CEM simulation system is established. The rationality of the structure design and the effectiveness of the motion control algorithm are verified by the simulation.

• Journal of Mechanical Science and Technology
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• 제19권10호
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• pp.1919-1931
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• 2005

Human joint motion can be kinematically described in three planes, typically the frontal, sagittal, and transverse, and related to experimentally measured data. The selection of reference systems is a prerequisite for accurate kinematic analysis and resulting development of the equations of motion. Moreover, the development of analysis techniques for the minimization of errors, due to skin movement or body deformation, during experiments involving human locomotion is a critically important step, without which accurate results in this type of experiment are an impossibility. The traditional kinematic analysis method is the Angular-based method (ABM), which utilizes the Euler angle or the Bryant angle. However, this analysis method tends to increase cumulative errors due to skin movement. Therefore, the objective of this study was to propose a new kinematic analysis method, Position-based method (PBM), which directly applies position displacement data to represent locomotion. The PBM presented here was designed to minimize cumulative errors via considerations of angle changes and translational motion between markers occurring due to skin movements. In order to verify the efficacy and accuracy of the developed PBM, the mean value of joint dislocation at the knee during one gait cycle and the pattern of three dimensional translation motion of the tibiofemoral joint at the knee, in both flexion and extension, were accessed via ABM and via new method, PBM, with a Local Reference system (LRS) and Segmental Reference system (SRS), and then the data were compared between the two techniques. Our results indicate that the proposed PBM resulted in improved accuracy in terms of motion analysis, as compared to ABM, with the LRS and SRS.

• Journal of Korean Neurosurgical Society
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• 제60권1호
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• pp.30-39
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• 2017

Objective : To compare the clinical outcomes and biomechanical effects of total disc replacement (TDR) and posterior cervical foraminotomy (PCF) and to propose relative inclusion criteria. Methods : Thirty-five patients who underwent surgery between 2006 and 2008 were included. All patients had single-level disease and only radiculopathy. The overall sagittal balance and angle and height of a functional segmental unit (FSU; upper and lower vertebral body of the operative lesion) were assessed by preoperative and follow-up radiographs. C2-7 range of motion (ROM), FSU, and the adjacent segment were also checked. Results : The clinical outcome of TDR (group A) was tended to be superior to that of PCF (group B) without statistical significance. In the group A, preoperative and postoperative upper adjacent segment level motion values were $8.6{\pm}2.3$ and $8.4{\pm}2.0$, and lower level motion values were $8.4{\pm}2.2$ and $8.3{\pm}1.9$. Preoperative and postoperative FSU heights were $37.0{\pm}2.1$ and $37.1{\pm}1.8$. In the group B, upper level adjacent segment motion values were $8.1{\pm}2.6$ and $8.2{\pm}2.8$, and lower level motion values were $6.5{\pm}3.3$ and $6.3{\pm}3.1$. FSU heights were $37.1{\pm}2.0$ and $36.2{\pm}1.8$. The postoperative FSU motion and height changes were significant (p<0.05). The patient's satisfaction rates for surgery were 88.2% in group A and 88.8% in group B. Conclusion : TDR and PCF have favorable outcomes in patients with unilateral soft disc herniation. However, patients have different biomechanical backgrounds, so the patient's biomechanical characteristics and economic status should be understood and treated using the optimal procedure.

• 한국운동역학회지
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• 제18권3호
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• pp.51-59
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• 2008

본 연구는 국가대표 절단장애 휠체어 탁구선수를 대상으로 절단장애 휠체어 탁구의 일반적 스트로크 운동형태를 알아보기 위해 실행되었다. 연구대상은 절단장애 1명을 선발하여 10회에 걸쳐 스트로크 하는 영상을 수집하였다. 그 중 대상자와 코치가 지정하는 3개의 영상을 연구대상으로 정하였다. 스트로크 하는 팔의 팔꿈치의 굴곡신전, 어깨의 굴곡신전, 어깨의 회전, 그리고 허리의 회전을 분석하였다. 포핸드 스트로크는 일반적으로 치는 듯한 동작을 나타낼 것으로 예상했으나 오른팔의 외측회전으로 만들어진 백스윙과 내측회전으로 만들어지는 회전에 의지하여 스트로크하고 있었다. 백핸드 스트로크는 예상대로 기시부인 몸통이 스트로크에 관여하지 않고 말초부인 오른팔이 내측회전 백스윙을 이루고 외측회전으로 임팩트를 이루는 미는 듯한 동작을 나타내고 있었다. 포핸드 스트로크 일반적인 스윙동작을 나타내는 다중분절시스템의 원리에 의해 치는 듯한 동작을 보일 것으로 예상했지만 절단장애인인 대상자는 기시부와 말초부로 이어지는 연결구조가 명확하게 나타나지 않았다. 다만 어깨의 회전폭이 스트로크 성공여부를 결정지었다.

• 한국운동역학회지
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• 제23권4호
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• pp.369-376
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• 2013

The purposes of this study were to assess dynamic stability toward pelvis-spine column distortion during running and to compare the typical three-dimensional angular kinematics of the trunk motion; cervical, thoracic, lumbar segment spine and the pelvis from the multi-segmental spine model between exercise group and non-exercise group. Subjects were recruited as exercise healthy women on regular basis (group A, n=10) and non-exercise idiopathic scoliosis women (group B, n=10). Data was collected by using a vicon motion capture system (MX-T40, UK). The pelvis, spine segments column and lower limbs analysiaed through the 3D kinematic angular ROM pattern. There were significant differences in the time-space variables, the rotation motion of knee joint in lower limbs and the pelvis variables; obliquity in side bending, inter/outer rotation in twisting during running leg movement. There were significant differences in the spinal column that is lower-lumbar, upper-lumbar, upper-thoracic, mid-upper thoracic, mid-lower thoracic, lower thoracic and cervical spine at inclination, lateral bending and twist rotation between group A and group B (<.05, <.01 and <.001). As a results, group B had more restrictive motion than group A in the spinal column and leg movement behaved like a 'shock absorber". And the number of asymmetry index (AI) showed that group B was much lager unbalance than group A. In conclusion, non-exercise group was known to much more influence the dynamic stability of equilibrium for bilateral balance. These finding suggested that dynamic stability aimed at increasing balance of the trunk ROM must involve methods and strategies intended to reduce left/right asymmetry and the exercise injury.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1993년도 추계학술대회 논문집
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• pp.75-79
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• 1993

The Thermally Stimulated Current(TSC) method has been allied to study the influence of the structural change and interface on the electrical properties of epoxy composites. Three DGBA- MeTHPA matrix model samples mixed different ratios arts silica(SiO$_2$) filled sample and silaln treating-filled sample have been studied. Above room temperature, the relaxation mode ${\alpha}$ peak associated with T$\_$g/ has been located at 110$^{\circ}C$. Below glass transition temperature(T$\_$g/), three relaxation modes are observed in all samples : a ${\beta}$ mode situated at 10$^{\circ}C$, a ${\gamma}$ mode located at -40$^{\circ}C$ and a $\delta$mode appeared in -120$^{\circ}C$, which may be due to segmental motion, side chains, substitution and terminal groups. The analysis of its fine structure indicates that constitution of elementary processes is characterized by the activation energy and relaxation time. Also the change of the molecular structure and their thermal motion are compared with the relaxation mode and conduction mechanism in TSC spectra through the dielectric properties and FTIR measurements.

• 한국정밀공학회지
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• 제27권2호
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• pp.137-144
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• 2010

In general, spinal fusion surgery takes pressure off the pain induced nerves, by restoring the alignment of the spine. Therefore spinal fixation system is used to maintain the alignment of spine. In this study, a biomechanical study was performed comparing the SROM(Spinal Range Of Motion) of three types of system such as Rigid, Dynesys, and Fused system to analyze the behavior of spinal fixation system inserted in vertebra. Dynesys system, a flexible posterior stabilization system that provides an alternative to fusion, is designed to preserve inter-segmental kinematics and alleviate loading at the facet joints. In this study, SROM of inter-vertebra with spinal fixation system installed in the virtual vertebra from L4 to S1 is estimated. To compare with spinal fixation system, a simulation was performed by BRG. LifeMOD 2005.5.0 was used to create the human virtual model of spinal fixation system. Through this, each SROM of flexion, extension, lateral bending, and axial rotation of human virtual model was measured. The result demonstrates that the movement of Dynesys system was similar to normal condition through allowing the movement of lumbar.

• 대한골관절종양학회지
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• 제2권1호
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• pp.101-105
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• 1996

Prosthetic reconstruction of musculoskeletal defects about the knee for tumor has many advantages, particularly the maintenance of motion and immediate functional restoration. But, prosthetic reconstruction has inherent limitations in terms of long-term durability. The authors have reported here a patient who had mechanical failure at 61 months later following use of a modular resection system to reconstruct the segmental defect of proximal tibia in osteosarcoma. In this case, another technique of extensor mechanism reconstruction using Achilles tendon allograft was attempted. Because of the concerns involving durability of tumor prosthesis, increased emphasis has to be placed on innovation in prosthetic design.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.187-187
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• 2006

A new type solid polymer electrolyte (SPE) composed of poly (vinyl alcohol) (PVA) and lithium trifluoromethanesulfonate ($LiCF_{3}SO_{3}$) was prepared by means of the solution cast technique to observe that Li ion can move by ion hopping decoupled from polymer segmental motion inside of the 'fast cationic transport process'. The highest ion conductivity of the SPEs obtained from ac impedance measurements was $1.42{\times}10^{-3}S/cm$ at room temperature for SPE with 80wt% of salt concentration. Using LSV, we found that the SPEs had good electrochemical stabilities and using FT-IR and AFM, we found the formation of network-like structure.

• 한국기계가공학회지
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• 제10권5호
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• pp.51-57
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• 2011

The lightweight and compact actuator with high power is required to perform motion with multiple degrees of freedom. To reduce the size and inertia of a robot manipulator, the mechanical transmission system is used. The shape memory alloy(SMA) is similar to the muscle-tendon-bone network of a human hand. However, there are some drawback and nonlinearity, such as the hysteresis and the stress dependence. In this paper, the design of the underactuated robot hand is studied. The 3-finger dexterous hand is driven by the SMA actuator using segmental mechanism. This digital approach enables to overcome the nonlinearity of SMA wire. The translational displacement of SMA actuator required to bend a phalanx of the underactuated robot hand is estimated and the bending angle of the underactuated robot hand according to input displacement of SMA actuator is predicted by the multi-body dynamic analysis.