• 제어로봇시스템학회논문지
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• 제20권8호
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• pp.875-881
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• 2014

The redundancy resolution of the seven DOF (Degree of Freedom) upper limb exoskeleton is key to the synchronous motion between a robot and a human user. According to the seven DOF human arm model, positioning and orientating the wrist can be completed by multiple arm configurations that results in the non-unique solution to the inverse kinematics. This paper presents analysis on the kinematic and dynamic aspect of the human arm movement and its effect on the redundancy resolution of the seven DOF human arm model. The redundancy of the arm is expressed mathematically by defining the swivel angle. The final form of swivel angle can be represented as a linear combination of two different swivel angles achieved by optimizing two cost functions based on kinematic and dynamic criteria. The kinematic criterion is to maximize the projection of the longest principal axis of the manipulability ellipsoid of the human arm on the vector connecting the wrist and the virtual target on the head region. The dynamic criterion is to minimize the mechanical work done in the joint space for each of two consecutive points along the task space trajectory. The contribution of each criterion on the redundancy was verified by the post processing of experimental data collected with a motion capture system. Results indicate that the bimodal redundancy resolution approach improved the accuracy of the predicted swivel angle. Statistical testing of the dynamic constraint contribution shows that under moderate speeds and no load, the dynamic component of the human arm is not dominant, and it is enough to resolve the redundancy without dynamic constraint for the realtime application.

• Imaging Science in Dentistry
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• 제36권4호
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• pp.199-206
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• 2006

Purpose: The purpose of this study was to evaluate comparison of static MRI and pseudo-dynamic (cine) MRI in temporomandibular joint (TMJ) disorder patients. Materials and Methods: In this investigation, 33 patients with TMJ disorders were examined using both conventional static MRI and pseudo-dynamic MRI. Multiple spoiled gradient recalled acquisition in the steady state (SPGR) images were obtained when mouth opened and closed. Proton density weighted images were obtained at the closed and open mouth position in static MRI. Two oral and maxillofacial radiologists evaluated location of the articular disk, movement of condyle and bony change respectively and the posterior boundary of articular disk was obtained. Results: No statistically significant difference was found in the observation of articular disk position, mandibular condylar movement and posterior boundary of articular disk using static MRI and pseudo-dynamic MRI (P<0.05). Statistically significant difference was noted in bony changes of condyle using static MRI and pseudo-dynamic MRI (P<0.05). Conclusion: This study showed that pseudo-dynamic MRI didn't make a difference in diagnosing internal derangement of TMJ in comparison with static MRI. But it was considered as an additional method to be supplemented in observing bony change.

• 한국콘텐츠학회논문지
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• 제18권12호
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• pp.468-488
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• 2018

메이커 운동은 필요한 물건을 직접 만드는 사람들이 모여, 창의적 만들기를 통해 지식과 경험을 공유하는 사회와 문화의 움직임이다. 그러나 지난 10년간 메이커 운동이 빠르게 성장하면서, 어디까지를 메이커 운동으로 볼 것인지에 대한 공감대가 아직 부족하다. 앞으로의 발전 방향성을 모색하기 위해서는, 지금까지 메이커 운동이 어떻게 변화해 왔는지를 조망하는 것이 필요하다. 본 연구는 메이커 운동에 대한 이슈가 일반 미디어에서 어떻게 변화됐는지를 파악하기 위하여 언론 기사들을 텍스트 기반의 빅데이터 분석 방법론을 활용하여 분석한다. 특히 시간에 따른 관심의 변화를 다각도로 분석하기 위하여 키워드 네트워크 분석과 동적 토픽 모델을 통합적으로 적용한다. 키워드 네트워크는 메이커 운동의 발전을 분석하기 위하여 단어 수준에서 시기별 주요 키워드를 도출하고, 동적 토픽 모델은 메이커 운동이 아우르는 다양한 분야 관점에서 관심도의 변화를 단어와 토픽, 문서의 세 가지 수준에서 파악할 수 있도록 도와준다. 결과적으로 주요 토픽은 창업, 메이커스페이스, 메이커 교육 등이 식별되었고, 주요 키워드는 3D프린터와 기업에서 교육으로 변화된 것을 확인할 수 있다.

• 한국화재소방학회논문지
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• 제34권3호
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• pp.110-115
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• 2020

본 연구는 소방훈련시 화학보호복 착용시 동작만족도를 분석하여 소방공무원의 안전을 위한 기초자료 제공을 목적으로 한다. 정적 동작만족도는 일반근무복에 비하여 화학보호복의 경우 21.7%~47.8% 정도 낮게 나타났다. 화학보호복 착용시 정적 동작자세에서는 고개 최대한 젖혀서 천장보기, 두팔 몸 앞에서 끌어안기, 비스듬히 굽혀 앉기, 과도하게 쪼그리고 앉기의 동작들이 낮게 나타났으며 통계적으로도 유의하게 낮은 결과를 보였다(p < .001). 동적 동작만족도는 일반근무복에 비하여 화학보호복의 경우 19.2%~47.8% 정도 낮게 나타났다. 화학보호복 착용시 동적 동작자세에서는 뛰기, 중량물 20 kg 허리까지 들어올리기, 중량물 20 kg 들어 1 m 옮기기, 들것 들고 앞으로 걷기, 들것 들고 뒤로 걷기의 동작들이 낮게 나타났으며 통계적으로도 유의하게 낮은 결과를 보였다(p < .001).

• 소성∙가공
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• 제5권4호
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• pp.327-336
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• 1996

The effect of dynamic strain aging on high temperature deformation behaviour of the A-Mg alloy was investigated by strain rate change tests and stress relaxation tests between 20$0^{\circ}C$and 50$0^{\circ}C$. Yield point, short stress transient and periodic discontinuities on the stress-strain curve were considered as an evidence of the effect of dynamic strain aging. With this criterion two distinct strain rate-temperature regimes could be manifested. Dynamic strain aging was considered to be effective in the high temperature-low strain rate regime, whereas dynamic recovery was a dominant deformation mechanism in the low temperature-high strain rate regime. It was found that dynamic strain aging in the high temperature deformation was governed by the mechcanism of diffusion-controlled, viscous dislocation movement.

• 한국실내디자인학회논문집
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• 제20권3호
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• pp.3-12
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• 2011

The purpose of this study is to analyse the diagrammatic design approaches and programmatic design approaches in contemporary architecture, so that this reveals the sequential systems of circulation in the space and liberal movement of the visitors in the buildings of those diagrammatic and programmatic architecture. Contemporary architecture generates the new forms and meanings through the dynamic visions and perspectives. Such a variation of sequential vistas and dynamic visions produce a perception of time and a potential movements of axis in the perspective. This study give the systematic body to the relations among visions, movements, sequences, forms, circulations and time. Diagrammatic and programmatic design approaches show the heterogeneous spaces and the informal architectures in contemporary architecture. Therefore, movements of various view points, differrentiations of objects in the perspectives, and multiple view frames appears in the designs of initiative architects. In conclusion, this study systemizes the concepts of time, sequential movements, and perceptions of events in contemporary architecture through the analyse of 18 architectural works of important architects in 2000s. And this shows details of the transitional movement of space and the perception of time in contemporary Architecture. The Being of the active time constructs formal transformations, spacial differentiations, accumulations of human behaviors, and movements of circulations involved with experiences of the field of senses. Therefore, Zeitlichkeit is perceived through concepts of the sequences of those spaces, forms, behaviors, and memories.

• 대한인간공학회:학술대회논문집
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• 대한인간공학회 1995년도 추계학술대회논문집
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• pp.156-163
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• 1995

An experimental protocol was developed and tested in this study in order to quantify the motor control capability of the trunk movement for both healthy subjects and low-back pain (LBP) patients. Information processing capacity (bits/second) (Fitts, 1954) and dynamic motor perfor- mance such as flexion/extension velocity and acceleration were measured as motor control parameters under the controlled range of motion (ROM). In this study, the original experimental propocol (Kim et al., 1993, 1994) was re-designed to reduce the length of the test via a series of statistical analyses for clinical application. The accuracy of the shortened protocol was statistically examined and indicated no difference conpared to the original protocol in terms of evaluating information processing capacity. This protocol was also tested among ten healthy subjects and ten LBP patients for validation purpose. The results showed that the information processing capacity was not significantly diffenent between two groups due to the large variation although there was an apparent mean difference. Average movement time showed a significant increase in LBP patients com- pared to healthy subjects. In conclusion, it was found that the new short experimental protocol could quantify the motor control capability of neuromuscular system of the trunk and also showed the applicability to patient population.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1998년도 춘계학술대회 논문집
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• pp.143-147
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• 1998

As the accuracy of manufactured goods needed high-accuracy processing has made the efficiency of NC and measurment technology develop, the innovation of machine tools has influence the development of the semi-conductor and optical technology. We can mention that a traction role of the acceleration for the development like that depends on the development of the measurement technics - Stylus instrument method, STM, SEM, Laser interferometer method - which are used for measuring the movement accuracy of machine tools. The movement error factors in movement accuracy are expressed as yaw, roll, and pitch etc. Machining center has 21 movement error factors including of 3 axies joint errors because that has 3 axies and has been measured as the standard of the unloaded condition until now inspite of getting static, dynamic, and servo-gain errors in the case of expending the error range. Therefore, this study tries to measure position accuracy according to loading on the X-Y table of the machining center.

• International Journal of Naval Architecture and Ocean Engineering
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• 제3권2호
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• pp.122-125
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• 2011

In this work, the movement pattern of a floating breakwater is numerically analyzed using Smoothed Particle Hydrodynamic (SPH) method as a Lagrangian scheme. At the seaside, the regular incident waves with varying height and period were considered as the dynamic free surface boundary conditions. The smooth and impermeable beach slope was defined as the bottom boundary condition. The effects of various boundary conditions such as incident wave characteristics, beach slope, and water depth on the movement of the floating body were studied. The numerical results are in good agreement with the available experimental data in the literature The results of the movement of the floating body were used to determine the transmitted wave height at the corresponding boundary conditions.

• The Journal of Korean Physical Therapy
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• 제16권2호
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• pp.22-32
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• 2004

The purpose of this study was to examine the effect of ankle-foot orthosis and lumbosacral orthosis on movement patterns used to rise from the supine position to erect stance. Thirty-two healthy adults participated. Subjects were videotaped while rising from a supine position on a floor mat. Each subject performed 10 trials each of three condition;general condition, right ankle-foot orthosis, lumbosacral orthosis. subjects rose most commonly using a symmetrical push pattern of the upper extremities, a symmetrical squat pattern in the lower extremities, a symmetrical in the trunk under each of three conditions. Changes in the incidence of movement patterns occurred in lower extremities of the ankle-foot orthosis and lumbosacral orthosis condition and trunk of the ankle-foot orthosis condition. From a dynamic pattern theory perspective, ankle motion is a control variable for the supine position to erect standing movement.