• 대한기계학회논문집B
• /
• 제20권4호
• /
• pp.1510-1520
• /
• 1996

An experimental study on the flow over the axisymmetric backward-facing step was carried out. The purpose of the present study is to investigate the effect of the separating streamline curvature on the reattachment length and to understand the structure of recirculating flows. Local mean and fluctuating velocity components were measured in the separating and reattaching axisymmetric region of turbulent boundary layer on the wall of convex cylinder placed in a water tunnel by using 2-color 4-beam fiber optics laser Doppler velocimetry. The study demonstrates that the reattachment length increases with increasing separating streamline curvature. It is also observed that the reverse flow velocity and turbulent kinetic energy increase with an increase in the separating streamline curvature. In addition, the behavior of maximum turbulent stresses show that the effect of separating streamline curvature is larger in the region of recirculating zone(X/H<2) than in the region of reattachment point.

• 보건의료산업학회지
• /
• 제6권3호
• /
• pp.219-229
• /
• 2012

In these days, the interest on medical industry is increasing around the world. This paper attempts to estimate the economic effects of the medical and measuring instrument industry through the Input-Output Analysis. Especially, 78*78 Sector Tables were used as the first analysis tool. So then, 79*79 Sector Tables adjusted were used for that industry. The main analysis tools of this study are comparing and analyzing backward and forward linkage effect, the induced effect of the self industry and other industries and the induced coefficients such as products, value-added, employee's pay, sales surplus, employment. According to the result of analysis, the medical and measuring instrument industry has great economic impacts which affects the major macroeconomic factors such as production and backward linkage effect. And the induced effects of the self medical and measuring instrument industry are significant compared to other industries in aspects of production, employee's pay and sales surplus.

• 한국산학기술학회논문지
• /
• 제13권5호
• /
• pp.2199-2205
• /
• 2012

본 논문은 속도변화에 따른 후방보행 훈련이 하지의 넙다리 근육에 미치는 영향을 알아보기 위한 것으로 30명의 대상자를 무작위로 세 집단; 실험군I(전방보행 5km/h: 10명), 실험군II(후방보행 5km/h: 10명), 실험군III(후방보행 2.5km/h: 10명)으로 나누어 실험하였다. 실험은 4주간 주 4회 30분씩 실시하였으며 실험 전과 실험 4주 후에 각 실험군의 넙다리곧은근의 활성도와 넙다리네갈래근의 근력을 측정하였다. 연구의 결과 넙다리곧은근의 활성도는 전방 보행 군보다 후방보행 군에서 더 의미 있는 변화를 보였으며 실험군III보다 실험군II에서 더 의미 있는 변화를 나타냈다. 넙다리네갈래근의 근력 또한 전방보행 군보다 후방보행 군에서 더 의미 있는 변화를 보였으며 실험군III보다 실험군II에서 더 의미 있는 변화를 나타냈다. 이상의 결과에 따라 후방보행이 전방보행에 비해 넙다리 근육의 근 활성도와 근력에 보다 효과적이라고 할 수 있으며 초기 재활에서 느린 속도의 후방보행이 효과적으로 활용될 수 있음을 알 수 있다.

• Physical Therapy Rehabilitation Science
• /
• 제6권3호
• /
• pp.120-126
• /
• 2017

Objective: The purpose of this study was to investigate the effects of backward treadmill gait training between underwater and ground environments on strength, proprioception, and walking ability in persons with stroke. Design: Randomized control trial. Methods: Twenty eight subjects participated in the study in which they were randomly assigned to either the underwater backward treadmill training (UBTT) group (n=13) or the BTT group (n=15). In both groups, forward gait training was performed for 20 minutes on the ground treadmill. The UBTT group performed backward gait on an underwater treadmill for 20 minutes while the BTT group performed backward gait on a ground treadmill for 20 minutes. The gait training in each group was performed twice a week for a total of six weeks. Muscle strength, proprioception, and gait ability was assessed using a digital power meter, joint angle recurrence method using the smartphone protractor application, the Figure-of-Eight walk test (F8W) and the functional gait assessment (FGA) respectively. Results: Both groups showed significant improvement in strength, F8W and FGA scores after training (p<0.05). However, there was no statistically significant difference between the two groups. Both groups showed significant improvement in proprioception after training (p<0.05). In the comparison between the two groups, there was a greater significant change in the UBTT group for joint proprioception (p<0.05). Conclusions: In this study, it was found that both backward treadmill gait training programs were effective on strength, proprioception, and gait ability, and that underwater training was particularly effective on proprioception compared to ground training.

• 지역연구
• /
• 제31권4호
• /
• pp.71-90
• /
• 2015

본 연구는 R&D 사업의 효과분석을 위해서는 기간별 성과를 비교하며 분석하는 것이 당해 연도 성과만을 분석하며 비교하는 것보다 타당하다는 연구문제에서 출발한다. 이에 개별 기업이 지니는 성과 특성을 시계열 자료의 종적 비교 분석을 통해 기간에 따라 파악함으로써 지역연구개발사업의 효과를 입체적으로 파악하고 있다. 기업의 성과에 대한 객관적인 평가를 위해서 해당 R&D 사업 참여 기업의 매출액과 영업이익을 핵심변수로 하여 R&D 예산 투자의 경제적 성과를 중심으로 파악하고자 하였다. 경제적 성과에 대한 분석을 위해 Within 분석을 '기업 내 효과 분석'으로 조작적 정의(operational definition)하였으며 이를 토대로 국가 R&D 투자효과를 측정을 위한 방법론을 설정하였다. 분석결과 전기효과가 후기효과에 비해 큰 것으로 나타났으며 이는 지역R&D투자에 따른 성과가 지원기간 이후까지 지속되기보다 지원기간에 한시적으로 나타남을 의미한다.

• 한국소음진동공학회논문집
• /
• 제14권12호
• /
• pp.1338-1346
• /
• 2004

The positions of rotating sound sources have been localized by experiments with the Doppler effects removed. In order to de-Dopplerize the sound signals emitted from moving sources, two kinds of signal reconstruction methods were applied. One is the forward propagation method and the other is the backward propagation method. Forward propagation method analyze the source emission time based on the instantaneous distance between sensors and the assumed source position, then the signals are reconstructed with respect to the emission time. On the other hand, the backward method uses time delay to do-Dopplerize the acquired data for the received time of reference. In both techniques. the reconstructed signal data were processed using beamforming algorithm to produce power distributions at the frequencies of interest. Experiments have been carried out for varying frequencies, rotating speeds and the object distances. It is shown that the forward propagation method gives better performance in locating source position than the backward propagation method.

• 한국정보통신학회:학술대회논문집
• /
• 한국해양정보통신학회 2007년도 춘계종합학술대회
• /
• pp.171-174
• /
• 2007

본 논문은 역전파 알고리즘을 이용한 FF-PID 제어 시스템 구현에 관한 연구이다. 영상의 인식은 신경망 역전파를 사용하여 학습시킨다. FF-PID 제어기는 신경망의 목표치에 대한 출력층 오차값을 제어값으로 사용하여 이동물체의 응답특성을 향상시킨다. 실험결과, 시스템의 응답시간은 약 2.7(sec)였으며, 일반적인 차영상기법에 비하여 약 15% 목표치 응답이 향상되어, 효과적인 이동물체의 제어가 가능하였다.

• 한국전문물리치료학회지
• /
• 제4권1호
• /
• pp.30-38
• /
• 1997

The patients with hemiplegia show different body weight distribution as compared to normal subjects. These patients load their body weight more on sound leg than affected leg. The purpose of this study was to examine the effect of foot placement under three conditions: forward, intermediate, and backward placement, on body weight distribution and time needed to rise while assuming sit-to-stand. Fourteen patients with hemiplegia participated in the study. Their body weight distributions during sit-to-stand under the three different conditions were measured by a limb loader and time needed to rise was measured by a stopwatch. The data were analysed by the repeated measure of one-way ANOVA. Statistical Analysis demonstrated that body weight distribution was less asymmetric in backward foot placement. The difference of body weight bearing rate between sound leg and affected leg was significantly decreased as foot placement moved from forward to backward. These results show that backward foot placement during sit-to-stand make patient with henuplegia distribute their body weight more evenly on the lower extremity.

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 2003년도 춘계학술대회논문집
• /
• pp.347-350
• /
• 2003

The metal forming behavior and defect formation in Ti-6Al-4V tube during hot backward extrusion were investigated. To predict the forming-defects such as shear band, inner cracks or surface cracks, dynamic material model(DMM) including Ziegler's instability criterion and modified Cockcroft-Latham fracture criterion(C-L model) were used. These models were coupled to the internal variables generated from FE analysis. The chilling effect and friction indicated a great influence on the deformation mode of the tube and the formation of surface cracks. The simulation results for the backward extrusion were compared with the experimental observations.

• 한국농업기계학회:학술대회논문집
• /
• 한국농업기계학회 1993년도 Proceedings of International Conference for Agricultural Machinery and Process Engineering
• /
• pp.1147-1156
• /
• 1993

In order to analyze lateral control in the backward maneuver of a tractor -trailer combination , a kinematic vehicle model and a human operator model with time delay were utilized for the operator/vehicle system. The analysis was carried out using the frequency domain approach. The open-loop stability of the vehicle motion was analyzed through the transfer functions. The sensitivity of the stability of the vehicle motion. to a change in the steering angle, was also analyzed. A mathematical model of the closed -loop operator/vehicle system was then formulated. The closed -loop stability of the operator /vehicle system was then analyzed. The effect of the delay time on the system was also analyzed through computer simulation.