• Journal of Mechanical Science and Technology
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• 제20권12호
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• pp.2105-2114
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• 2006

In this paper, a simplified model is studied to predict analytically the vibration from the helical gear system due to an axial excitation of helical gears. The simplified model describes gear, shaft, bearing, and housing. In order to obtain the axial force of helical gears, the mesh stiffness is calculated in the load deflection relation. The axial force is obtained from the solution of the equation of motion, using the mesh stiffness. It is used as a longitudinal excitation of the shaft, which in turn drives the gear housing through the bearing. In this study, the shaft is modeled as a rod, while the bearing is modeled as a parallel spring and damper only supporting longitudinal forces. The gear housing is modeled as a clamped circular plate with viscous damping. For the modeling of this system, transfer matrices for the rod and bearing are used, using a spectral method with four pole parameters. The model is validated by finite element analysis. Using the model, parameter studies are carried out. As a result, the linearized dynamic shaft force due to the gear excitation in the frequency domain was proposed. Out-of-plan displacement from the forced vibrating circular plate and the renewed mode normalization constant of the circular plate were also proposed. In order to control the axial vibration of the helical gear system, the plate was more important than the shaft and the bearing. Finally, the effect of the dominant design parameters for the gear system can be investigated by this model.

• 만화애니메이션 연구
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• 통권25호
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• pp.41-63
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• 2011

1995년 경 부터 국가의 애니메이션 산업 부흥 책에 의한 수많은 제작업체와 교육기관과 들이 생겨났다. 적극적인 국가적 재정지원에 힘입어 제작산업은 급속히 활성화되었고, 제작기술은 비약적 발전되었으며, 교육기관을 통해 수많은 인력들이 사회로 배출되고 있다. 많은 개발도상국들도 우리와 비슷한 애니메이션 산업화에 역점을 두는 양상을 보이고 있는 현실상황은, 산업적으로 우리에게 큰 압박이 되고 있다. 단시간 내 특정분야를 세계적으로 경쟁력 있는 산업으로 발전시킨다는 것은 결코 쉽지않다. 이러한 국제적 상황에 따른 우리의 대응책은, 기존 제작방식에서 벗어난, 혁신성과 창의성, 그리고 수준 높은 애니메이션 전문 인력 양산에 있다고 판단된다. 본 논문은 국가 경쟁력 강화를 위한 새로운 교육방식의 제안서이다. 애니메이션 제작의 핵심인 애니메이팅 작업은, 철저히 애니메이터의 예술적, 기술적 기량에 좌우된다. 기존의 이론위주, 현장성이 결여된 학습내용의 맹점을 보완하고, 좀 더 실제적 애니메이팅 학습법을 구현하기 위해, 선호도 높은 작품의 빈도수 많은 캐릭터 동작을 바탕으로, 동작을 서서히 행하는 가운데, 역학적 원리를 감각적으로 스스로 체득하게 하는 슬로우 모션(Slow Motion) 효과를 병합하여, 애니메이터 지망 학생들의 감각적인 연기동작과 연출력 향상에 도움을 주기 위한 동작 학습법을 제시하고자 한다.

• 대한가정학회지
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• 제20권4호
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• pp.155-168
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• 1982

What is attempted here is to find out an optimum method for the design of physical environments that could save human energy expenditures and safely perform household duties. There are, if any, very little amount of research done in this area. This is particulary so when the work relates to the designing of household storage facilities in the light of the energy metabolism of human body. The first step to this study, therefore, is to find out the ways by which we can determine the energy metabolism of human body accurately. To measure the volume and the concentration of human respiration continuously and automatically, a new apparatus is selected here. This includes the recording system with the Wright Respirometer and the Expired Gas Analyzer as well as the computer system to multiply volume by concentration of human respiration and to integrate them for a given time. Then, the author experimented on the reliability of this apparatus and came to the conclusion that this apparatus satisfied our need to research the energy metabolism of human body. Next, the general plan and procedures to experiment with this apparatus have been determined as follows: 1) subjects are three young and sound females. Their physical characteristics are shown in Table 1 and most approximates the standard characteristics of Japanese females, 2) height of open shelves is selected in such away as to correspond to the respective height of each subject(see Table 2), 3) utensils to be stored are box shaped object, which weight is 0.5kg, 1.0kg, 2.0kg or 3.0kg, 4) working motions are given while one or two hands as to place utensil on each shelf from the standard working board, 85 cm in height and then to place back it on the board from the shelf and repeated in constant velocity as 10 times per a minute, 5) each posture of motion is chosen by each subject in free, 6) procedures of measurement of human energy metabolism ard shown at(6), 1, Section 3 as specific methods for using this apparatus. Findings of this study are as follows: 1. Human energy expenditures for storing utensils on shelves by each subject are shown in quantity more accurately than in any other studies, under varying conditions about height of shelves, load of utensils and working motion with one hand and two hands (see Fig. 8~13 and Table 3). 2. Experimental formulae of human energy expenditure for that work are shown as formula (8), (9) and (10), to generalize results of 1. and to apply those for working motion under given conditions. 3. As results of analysis on gained data, we are able to show the standard model of human energy expenditures for storing untensils on shelves by the standard Japanese female (see Table 7 and Fig. 14).

• 대한예방한의학회지
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• 제16권2호
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• pp.17-30
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• 2012

Objectives : This study was to analyse the reasons for the early termination of our clinical trials that were to know the influences of Tai-chi on non-motor symptoms of Parkinson's disease. Methods : We stopped the primary study of Tai-chi to observe the changes of non-motor symptoms of Parkinson's disease. So we carried out the survey to our participants of clinical trials. We conducted the survey about the patient's characteristics of usual exercise, experience of Tai-chi, appropriate time allocation, difficulties of proceeding the program and patient's opinion for the improvement of education. And the 4 questions about the contributiveness of Tai-chi for the Parkinson's disease, usability of supplied references, difficulties and time allocation of education were using the questionaries form of 5-point scale(Likert scale). Results : The results of survey showed that the benefits of Tai-chi program for the improvement of symptoms was $3.15{\pm}0.89$ and difficulty of lecture was $3.76{\pm}1.09$. 41% of participants answered that the motions of the Tai-chi is difficult to follow and 17% of participants felt the imbalance during the motion of Tai-chi. Conclusions : Participants replied that the Tai-chi is hard for the patients of Parkinson's disease and the time for the education was too short to keep doing exercise. Thus we have plan to educate the patients of Parkinson's disease with Tai-chi program consists of easier motion by developing ourselves or searching previous studies.

• 한국콘텐츠학회논문지
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• 제14권9호
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• pp.1-13
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• 2014

가상 세계의 에이전트의 설계를 위해서 물리적 사실감뿐만 아니라 동적으로 변하는 상황에 대응하는 에이전트의 다양한 물리적 행동들의 구현이 필수적이다. 본 연구는 다양한 행동을 구현하기 위한 기본 동작들을 재활용한 복합적 행동 및 에이전트가 즉시 주위의 환경에 반응할 수 있는 기법을 구현한다. 또한 관절에 대한 에이전트의 신체 구조를 설계하고 기본 동작 또는 복합 동작을 실시간으로 표현한다. 이 기법을 구현하기 위해서, 기본적인 관절 회전을 위한 애니메이션 함수와 기본 동작으로 이루어진 전체적 동작을 구성하는 기능을 구현한다. 이러한 동작들은 에이전트의 목적을 달성하는 계획에 포함될 수 있다. 즉, 재활용된 기본 동작을 이용하여 다양한 행동을 쉽게 생성하는 기법을 개발한다. 본 연구는 '걸으면서 먹다'와 같은 병렬 행동을 구현할 때 뚜렷한 장점을 가진다. 이는 두 개 이상의 행동들은 우선순위에 따라 자연스럽게 병렬 행동으로 조합된다. 이를 증명하기 위해 몇 개의 복합 행동 및 병렬 행동을 구현한다.

• KIEAE Journal
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• 제14권2호
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• pp.37-46
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• 2014

University buildings are energy-guzzling facility that consume more than 10,000TOE within a campus annually. Even the consumption is on an upswing trend. Behind such high consumption are there cheap power rates for education facility, lack of high-efficiency equipment and ever-increasing use of various information equipment. Being keenly aware that greenhouse gas emission increases due to such rise of energy consumption, the present study carried out a case study. In the case study, the study chose the buildings of E university from top 10 universities that consume energy most in Seoul and examined the current status of their energy consumption and greenhouse gas emission. And then it set the reduction target of greenhouse gas by year. Putting aside a middle and long-termed strategy for later endeavor, it first established the 1st year's implementation plan (2014) for energy saving and greenhouse gas reduction with limited budget and according to greenhouse gas reduction target. The plan is specified as follows. Targets for energy saving are mainly divided into two sectors: machine equipment and electric equipment. 7 ideas were proposed. Three ideas to improve machine equipment are to replace with high-efficiency boilers and chillers and to adjust the position of the cooling tower. By doing so, it was estimated that energy could be saved by 176.34TOE in total and greenhouse gas could be reduced by 370.771t$CO_2$-eq. Four ideas to improve electric equipment include the replacement with LED lights, LED emergency lights and high-efficiency motors and the installation of motion sensors. It was calculated that such replacement could conserve 1,076.08TOE (electric energy) and reduce 2,181.420t$CO_2$-eq (greenhouse gas).

• International Journal of Ocean System Engineering
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• 제4권1호
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• pp.19-28
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• 2014

The tension leg platform (TLP) is a vertically moored structure with excess buoyancy. The TLP is regarded as moored structure in horizontal plan, while inherit stiffness of fixed platform in vertical plane. In this paper, a numerical study using modified Morison equation was carried out in the time domain to investigate the influence of nonlinearities due to hydrodynamic forces and the coupling effect between surge, sway, heave, roll, pitch and yaw degrees of freedom on the dynamic behavior of TLP's. The stiffness of the TLP was derived from a combination of hydrostatic restoring forces and restoring forces due to cables and the nonlinear equations of motion were solved utilizing Newmark's beta integration scheme. The effect of tethers length and wave characteristics such as wave period and wave height on the response of TLP's was evaluated. Only uni-directional waves in the surge direction was considered in the analysis. It was found that for short wave periods (i.e. 10 sec.), the surge response consisted of small amplitude oscillations about a displaced position that is significantly dependent on tether length, wave height; whereas for longer wave periods, the surge response showed high amplitude oscillations about that is significantly dependent on tether length.

• 한국콘텐츠학회논문지
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• 제15권3호
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• pp.40-47
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• 2015

ICT(정보통신: Information and Communication Technologies)에서 주요 분야로 각광받고 있는 가상현실(VR: Virtual Reality)영역은 이미 엔터테인먼트, 디자인 및 시뮬레이션 교육 등 다양한 분야에서 활용되고 있다. 특히, 문화관광분야를 비롯하여 사회 전반적인 영역에 더욱 확산 되고 있는 추세이다. 따라서, 본 논문에서는 문화관광 분야에서 가상현실 콘텐츠의 시장 선점 가능성 및 경쟁력 확보를 위하여 개선된 VR 콘텐츠를 기획 및 제작하였다. HMD(Head Mounted Display)에서 발생하는 인지부조화로 인한 시뮬레이션 멀미(simulation sickness) 현상을 개선시키기 위해 아웃포커스, 렌즈더스트, 모션블러 효과, 흔들림 효과를 최소화 하였다. 또한, 제작된 콘텐츠는 사용자의 몰입도 향상을 위해 효과적인 UI 디자인을 고려하여 설계하였다.

• 한국의학물리학회지:의학물리
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• 제19권2호
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• pp.89-94
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• 2008

토모치료기는 선형가속기에서 사용되는 세기 변조방사선치료와 Mega-voltage Computed Tomography (MVCT) 3차원 영상정보에 의한 영상유도방사선치료(Image Guide Radiation Therapy, IGRT)가 가능하고 나선식 빔 조사를 통해 표적과 정상조직에 효율적으로 선량(dose)을 집중하고 분산할 수 있다는 장점을 가진다. 이에 본 논문에서는 2006년 9월부터 운용을 시작한 국립암센터의 토모치료기를 이용하여 10명의 두경부암 환자를 대상으로 토모치료계획과 선형가속기기반 세기변조방사선치료계획의 선량분포를 비교하였으며 또한, 영상유도 방사선치료장치가 구비되지 못하여 환자의 위치보정이 부정확한 구형 세기변조방사선치료기에 대해 표적의 움직임에 따라 균일성(Homogeneity)과 정상조직부작용율(Normal Tissue Complication Probability, NTCP)이 상대적으로 어떻게 변화하는지 연구하였다. 이 연구를 위하여 토모치료기의 치료계획용 시스템인 Hi-Art (Hi-Art2_2_4 2.2.4.15, TomoTherapy Incorporated, 1240 Doming Way, Madison, WI S3717-1954, USA)와 선형가속기기반 세기변조방사선치료계획용 시스템인 CadPlan (CadPlan R.6.4.7, Varian Medical System Inc. 3100 Hansen Way, Palo Alto, CA 94304-1129, USA)을 이용한 역치료계획(inverse Planning)이 수행되었으며 치료계획은 각각의 환자에 대해 같은 표적과 최적화조건을 가지도록 고려되었다. 총 10명의 환자를 대상으로 한 연구결과, 환자의 신체내 외부가 완전히 고정되어 있는 이상적인 경우에 대해서 토모치료기를 이용한 치료계획이 선형가속기에 의한 세기 변조 방식보다 표적에 대해 보다 높고 일정한 선량분포를 주면서도 주변 장기의 선량이 선량체적 히스토그램(Dose Volume Histogram, DVH)에서 오히려 감소함을 보여 주었다 또한 토모치료기의 MVCT를 이용하여 한 달간 토모 환자의 표적위치변화를 측정하였고, 이를 토대로 평균 표적위치변화를 고려하였을 경우 선형가속기기반 세기변조방사선치료계획인 CadPlan에서 표적의 등가균질선량(Equivalant Uniform Dose, EUD)이 감소하고 정상조직의 부작용율의 발생가능성이 상대적으로 증가함을 발견하였다.

• Journal of Acupuncture Research
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• 제35권3호
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• pp.120-128
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• 2018

Background: Adhesive capsulitis (AC) is a common condition that includes shoulder pain and limited movement. Despite more than 100 years of AC treatment, the most efficacious treatment remains unclear. The aim of this study was to evaluate the feasibility of a randomized controlled trial (RCT) using acupuncture for AC. Methods: Thirty participants with AC were randomly assigned to acupuncture (A) or sham acupuncture (SA) groups. The participants received 15 acupuncture sessions over 6 weeks, and follow-up occurred for an additional 4 weeks thereafter. The primary clinical outcome was the numeric rating scale (NRS) for shoulder pain 6 weeks from the baseline. Secondary outcomes included range of motion (ROM) in the shoulder, the shoulder pain and disability index (SPADI), the EuroQol-5 dimensions (EQ-5D), the Pittsburgh sleep quality index (PSQI), and the patient global impression of change (PGIC). Results: Thirty participants were enrolled out of 37 screened individuals. Recruitment was conducted between August 2014 until May 2015. A total of 28 participants (93%) completed the 6-week intervention, and 26 participants (87%) completed the study. NRS, ROM, SPADI, EQ-5D, PSQI, and PGIC scores improved in both the experimental group and the sham group after 6 weeks, but the difference between the groups was not statistically significant. Adverse events were reported by 12 participants, although these events were not associated with acupuncture. Conclusion: A future RCT for AC may be feasible with some modifications to the recruitment plan and the secondary outcome measurement methods.