• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 춘계학술대회논문집
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• pp.780-785
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• 2003

Recently the trends in information storage devices need small size, mobility, high capacity, and low power consumption etc. To satisfy those, the development of high performance actuator is an important issue. Compared with general linear actuator for optical disk drive, swingarm type rotary actuator is suitable to design in small form factor and has fast access time for random access. Swingarm actuator is designed considering the structural problem and the actuating force of VCM(Voice Coil Motor). The increase of mass caused by optical components makes vibration problems of swing-arm, therefore resonance frequency should be increased and inertia has to be reduced. ANSYS FEM tool is employed in optimizing swingarm. The VCM is designed using 3-D electro-magnetic analysis, and parameters of magnetic circuit are determined to matte large flux density. The large flux density enables to achieve low power consumption. VCM holder is designed to get the mass balance of total actuator and this balance reduces the magnitude of critical mode relative to pivot bearing, It is expected that swingarm type rotary actuator designed by this method is available to variable type of micro optical disk drives.

• Wind and Structures
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• 제18권4호
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• pp.391-422
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• 2014

The high frequency force balance (HFFB) technique provides convenient measurements of integrated forces on rigid building models in terms of base bending moments and torque and/or base shear forces. These base moments or forces are then used to approximately estimate the generalized forces of building fundamental modes with mode shape corrections. This paper presents an analysis framework for coupled dynamic response of tall buildings with HFFB technique. The empirical mode shape corrections for generalized forces with coupled mode shapes are validated using measurements of synchronous pressures on a square building surface from a wind tunnel. An alternative approach for estimating the mean and background response components directly using HFFB measurements without mode shape corrections is introduced with a discussion on higher mode contributions. The uncertainty in the mode shape corrections and its influence on predicted responses of buildings with both uncoupled and coupled modal shapes are examined. Furthermore, this paper presents a comparison of aerodynamic base moment spectra with available data sets for various tall building configurations. Finally, e-technology aspects in conjunction with HFFB technique such as web-based on-line analysis framework for buildings with uncoupled mode shapes used in NALD (NatHaz Aerodynamic Loads Database) is discussed, which facilitates the use of HFFB data for preliminary design stages of tall buildings subject to wind loads.

• 대한기계학회논문집A
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• 제40권5호
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• pp.483-488
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• 2016

플러그인 디지털 프레임웍은 계의 구성요소가 블랙박스 형태로 구성되어 있을 때 계의 응답을 해석하는 도구이다. 일반적으로 구성요소를 연결하는 동역학계의 연결부는 계의 응답에 크게 영향을 미치게 되고, 많은 경우 연결부의 특성은 변위와 주파수에 따라 달라지는 특성을 보인다. 그러므로 연결부의 특성에 대한 민감도의 계산은 전역적으로 수행되어야 한다. 본 연구에서는 플러그인 디지털 프레임웍에서 연결부의 전역민감도를 계산하는 방법을 주파수응답함수 기반의 부분구조합성법을 기반으로 제시한다. 일차 전역민감도는 무작위균형설계법을 이용하여 적은 수의 샘플링으로 각 인자영향을 계산할 수 있다. 이 방법은 승용차의 실내소음에 대한 각 연결부 강성의 민감도를 계산하는 예에 적용함으로써 그 효용성을 검증하였다.

• 대한통합의학회지
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• 제10권2호
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• pp.73-83
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• 2022

Purpose : Low back pain (LBP) is reported as a risk of experiencing musculoskeletal disorders due to muscle stiffness and hypokinetics. The lumbar spine in an unstable state causes imbalance and lumbar instability. Therefore, This study examined the effects of lumbar stabilization exercise and self-complex exercise program on pain, function, psychosocial level, static balance ability, and transverse abdominal muscle (TrA) thickness and contraction ratio in patients with lumbar instability. Methods : The design of this is a randomized controlled trial (RCT). Twenty-six LBP patients participated in this study. Screening tests were performed and assigned to the experimental group (n=13) and control group (n=13) using a random allocation program. Both groups underwent a lumbar stabilization exercise program. In addition, the experimental group implemented the self-complex exercise program. All interventions were applied three times per week for four weeks. The quadruple visual analog (QVAS), the Korean version of the Oswestry disability index (K-ODI), Korean version of fear-avoidance belief questionnaire (FABQ), static balance ability, TrA thickness, and contraction ratio were compared to evaluate the effect on intervention. Statistical significance was set at 𝛼=.05. Results : Both groups showed significant differences before and after the intervention in QVAS, K-ODI, FABQ, static balance ability, and TrA thickness in contraction (p<.05). In addition, significant differences in K-ODI and FABQ were observed between the experimental group and control group (p<.05). Conclusion : A lumbar stabilization exercise and self-complex exercise program resulted in reduced dysfunctions, psychosocial stability in patients with lumbar instability. Therefore, Lumbar stabilization exercise and self-complex exercise program for patients with lumbar instability are effective method with clinical significance in improving the function and psychosocial stability.

• 한국전자파학회논문지
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• 제13권2호
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• pp.208-216
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• 2002

본 논문에서는 X-형 모노펄스 축 곡조를 가지는 도파관 광벽 슬롯 배열 모노펄스 안테나의 설계 방법을 제안하고, 제작을 통하여 방법의 타당성과 안테나 특성을 검증하였다. 본 논문에서의 안테나는 크기가 작아서 연속 함수의 복사면 분포함수가 부적합하며, 모노펄스 축 구조가 X-형이기 때문에 안테나 자 분면이 대칭적이지 않다. 또한 도파관 높이가 0.1파장 정도로 매우 낮기 때문에 일반적인 경우와 같이 슬롯 특성을 쉽게 모델링 하기가 어렵다 이러한 이유 때문에, 본 논문에서는 무작위수를 이용하여 복사면 분포를 최적화하고, 이 과정에서 안테나 각 분면의 출력 파워가 같도록 복사 분면 가중치를 조절하였다. 또한 내삽법을 이용해서 모멘트 행렬의 일부를 미리 계산해서 사용함으로써 계산 속도를 높이고. 배열 합성 프로그램의 부프로그램으로 첨부하여 필요할 때마다 직접 계산해서 사용될 수 있도록 하였다. 이러한 방범으로 설계된 안테나를 직접 제작하여 28 ㏈i의 이득을 확인하였으며, 안테나 빔폭, 효율, 부엽준위도 설계치와 유사한 특성을 보였다.

• 지역사회간호학회지
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• 제18권1호
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• pp.56-68
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• 2007

Purpose: The present study analyzed the contents of exercise programs for the elderly in Korean and foreign articles. Method: This study analyzed 27 Korean and 20 foreign exercise-related articles selected from Web DBs using keywords 'exercise', 'exercise program' and 'exercise effect'. The collected data were analyzed using SPSS 11.5 through descriptive statistics, $x^2$ test and Fisher's exact test. Results: In the description of population, random sampling and informed consents, foreign articles were higher than Korean articles. In research design, foreign articles randomized controlled trials (RCTs) higher than Korean articles. The contents of exercise programs in the Korean and foreign articles were aerobic, walking and stretching. On the effects of exercise programs in the Korean articles, walking showed the highest frequency in the physical strength as well as muscle strength, balance and flexibility. In the foreign articles, walking and stretching showed high frequency in physical strength. Conclusion: Contents significant in exercise programs for the elderly were walking and stretching. In addition, regular exercise had a positive effect on muscle strength, flexibility and balance in the elderly.

• 대한물리치료과학회지
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• 제27권2호
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• pp.36-47
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• 2020

Background: This study purposed to provide meaningful information for the accumulation of knowledge on coordinative locomotor training in patients with stroke. Design: Meta-analysis. Methods: This study collected articles which the coordinative locomotor training in patients with stroke. For systematic meta-analysis, 6 articles were finally selected after searching based on the PICOSD criteria. This meta-analysis was conducted according to PRISMA guidelines. Randomized controlled trials were included and the risk of bias was evaluated for each study. Pooled standardized mean differences were calculated using a random effects model. To extract the effect size of each study, the R 3.5.3 software was used. Results: The meta-analysis showed that a total effects size was 1.23 indicating that coordinative locomotor training for patients with stroke had a maximum effect size. Conclusion: A meta-analysis is warranted for further research to determine the effects of coordinative locomotor training in patients with stroke on muscle strength, walking and range of motion.

• Physical Therapy Rehabilitation Science
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• 제9권4호
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• pp.252-260
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• 2020

Objective: Disorder of the autonomic nervous system is considered to be the cause of primary dysmenorrhea. The spine has a close relationship with the autonomic nervous system, and the sacrum is mechanically and neurologically connected to the uterus through ligaments. Therefore, this study was conducted to check the effect on the autonomic nervous system through measurement of heart rate variability by applying manual therapy to the sacroiliac joints of subjects with primary dysmenorrhea and to suggest an effective treatment method for dysmenorrhea. Design: Randomized controlled trial. Methods: Thirty females with dysmenorrhea were assigned to either the manual therapy group and sham treatment group according to the random treatment method. The manual therapy was applied to the sacroiliac joints, and the sham treatment was only treated with the hands placed in the same position of the intervention. Heart rate variability and the Visual Analogue Scale (VAS) were measured on the day when menstruation began ±2. Interventions were performed between the groups, followed by a 5-minute break and then re-measurements were made. Results: There were significant differences in autonomic balance and VAS scores in the manual therapy group before and after the intervention between groups (p<0.05). In the sham treatment group, there were significant differences in low frequency, autonomic balance, and VAS scores (p<0.05). There were significant differences in autonomic balance between groups (p<0.05). Conclusions: In females with primary dysmenorrhea, manual therapy applied to the sacroiliac joint was found to be effective for a short time on autonomic activity.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 추계학술대회 논문집 학회본부 B
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• pp.654-656
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• 1998

This paper presents an optimal identification method of nonlinear and complex system that is based on fuzzy-neural network(FNN). The FNN used simplified inference as fuzzy inference method and Error Back Propagation Algorithm as learning rule. And we use a HCM Algorithm to find initial parameters of membership function. And then to obtain optimal parameters, we use the genetic algorithm. Genetic algorithm is a random search algorithm which can find the global optimum without converging to local optimum. The parameters such as membership functions, learning rates and momentum coefficients are easily adjusted using the genetic algorithms. Also, the performance index with weighted value is introduced to achieve a meaningful balance between approximation and generalization abilities of the model. To evaluate the performance of the FNN, we use the time series data for 9as furnace and the sewage treatment process.

• Advances in Computational Design
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• 제1권3호
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• pp.275-296
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• 2016

This article presents an adaptive directional differential evolution (ADDE) algorithm and its application in solving discrete sizing truss optimization problems. The algorithm is featured by a new self-adaptation approach and a simple directional strategy. In the adaptation approach, the mutation operator is adjusted in accordance with the change of population diversity, which can well balance between global exploration and local exploitation as well as locate the promising solutions. The directional strategy is based on the order relation between two difference solutions chosen for mutation and can bias the search direction for increasing the possibility of finding improved solutions. In addition, a new scaling factor is introduced as a vector of uniform random variables to maintain the diversity without crossover operation. Numerical results show that the optimal solutions of ADDE are as good as or better than those from some modern metaheuristics in the literature, while ADDE often uses fewer structural analyses.