• 융합신호처리학회논문지
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• 제3권3호
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• pp.6-13
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• 2002

본 논문에서는 신호 교차로에서 red-time 및 green-time의 backward moving 충격파 속도를 자동 측정하는 영상처리 기반 방법을 제안한다. 충격파(shockwave)란 서로 다른 교통류 상태가 만나는 불연속적인 경계선을 의미하며, 충격파 속도는 충격파가 움직이는 속도 즉, 경계선의 기울기로 구해진다. 본 논문에서는 충격파 속도를 자동 측정하기 위해 거리-시간 다이어그램(distance-time diagram)을 작성하였다. 차량의 전역 추적을 통해서 모든 개별 차량의 이동 경로를 거리-시간 다이어그램에 나타내었고, 이동 경로 곡선의 기울기 변화 패턴을 분석하여 red-time 및 green-time의 backward moving 충격파 속도를 계산하였다. 제안된 방법을 신호 교차로에서 실험하였고 red-time 및 green-time backward moving 충격파 속도의 측정 결과를 얻었다. 충격파 속도를 측정하게 되면 차량 진행 방향의 교통 혼잡 상황을 쉽게 파악할 수 있으므로 고속 도로의 진입차선 제어, 교차로의 자동 신호제어에 효과적으로 응용할 수 있다.

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

• 한국산학기술학회논문지
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• 제16권11호
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• pp.7285-7292
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• 2015

본 연구의 목적은 생체역학적 변인을 근거로 하여 후진보법의 전방향 보행(댄스보행)이 후방보행처럼 재활과 걷기운동으로써의 가능성을 규명하는 것이다. 실험대상자는 13명의 여성댄스 전문가로 자료수집을 위하여 12대의 적외선카메라와 2대의 지면반력기가 동조되어 사용되었다. 연구결과에 따르면 댄스보행의 보속, 활보장과 양 하지지지기시간은 후방보행보다 크고, 활보폭은 작았으며 관절각범위, 관절모멘트와 관절파워의 최대치 출현 빈도에서 댄스보행이 후방보행보다 더 많았다. 이러한 결과들은 댄스보행이 재활과 걷기운동에 후방보행에 버금가는 훌륭한 도구임을 판단하는데 충분하다.

• 대한물리치료과학회지
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• 제28권2호
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• pp.1-9
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• 2021

Background: The requirements for postural and motor control in backward walking training (BWT) may improve balance and walking speed in patients with acute stroke. The aim of this study was to analyze the effect of BWT on balance, balance confidence, and fall efficacy in this population. Design: Randomized controlled pilot trial. Methods: This study included 14 subjects with acute stroke (onset of illness less than one month). They were randomly allocated to a BWT (n=7) or forward walking training (n=7) group and observed five times in a week for a period of two weeks. Measurements were taken before and after the experiment using the Berg balance scale (BBS), Activities-specific balance confidence scale (ABC), and Fall efficacy scale (FES). Results: The BBS, ABC and FES scores obtained in both groups after the experiment were significantly higher than those before the experiment (p<0.05). In addition, the BBS, ABC, and FES scores in the experimental group were significantly higher than those in the control group (p<0.05). Conclusion: These findings indicate that BWT improved balance and balance confidence and decreased the risks of fall in patients with acute stroke. Further study is needed to better understand the effects of backward walking in acute stroke patients.

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

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2003년도 The 8th Asian Symposium on Precision Forging ASPF
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• pp.162-166
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• 2003

In combined forward-backward extrusion with controlled forward speed by a counter punch, accurate parts with forward rod can be formed. As an extension of this method, reverse extrusion is proposed, in which the extruded forward rod is pushed back while the main punch is kept at the final position after the forward-backward extrusion process. The experiment is carried out using lead as a model material. With the reverse extrusion method, longer forward rods can be formed without under-filling defect than that by combined extrusion with controlling extrusion speed.

• Nuclear Engineering and Technology
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• 제43권6호
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• pp.531-546
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• 2011

The backward differentiation formula (BDF) method is applied to a three-dimensional reactor kinetics calculation for efficient yet accurate transient analysis with adaptive time step control. The coarse mesh finite difference (CMFD) formulation is used for an efficient implementation of the BDF method that does not require excessive memory to store old information from previous time steps. An iterative scheme to update the nodal coupling coefficients through higher order local nodal solutions is established in order to make it possible to store only node average fluxes of the previous five time points. An adaptive time step control method is derived using two order solutions, the fifth and the fourth order BDF solutions, which provide an estimate of the solution error at the current time point. The performance of the BDF- and CMFD-based spatial kinetics calculation and the adaptive time step control scheme is examined with the NEACRP control rod ejection and rod withdrawal benchmark problems. The accuracy is first assessed by comparing the BDF-based results with those of the Crank-Nicholson method with an exponential transform. The effectiveness of the adaptive time step control is then assessed in terms of the possible computing time reduction in producing sufficiently accurate solutions that meet the desired solution fidelity.

• 한국항공우주학회지
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• 제40권10호
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• pp.840-845
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• 2012

본 논문에서는 후향계단(Backward Facing Step) 유동장의 유동운동에 대한 ARX(Auto Regressive eXogenous) 모델링 기법을 제시한다. BFS 유동장 모델링을 위해 밀도를 모드분석을 통해 고유 공간모드와 시간계수를 추출한다. 입력 차수와 상태변수 차수는 각각 유동장 스팩트럼 분석과 시간계수 분석을 통해 결정한다. 또한, 유동장의 속도 분석을 통해 ARX의 입력 지연 차수를 결정한다. 한편, ARX 모델의 계수는 신경망을 이용하여 설계한다.

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

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2003년도 Proceeding
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• pp.236-242
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• 2003

ATM ABR service controls network traffic using feedback information on the network congestion situation in order to guarantee the demanded service qualities and the available cell rates. In this paper we apply the control method using queue length prediction to the formation of feedback information for more efficient ABR traffic control. If backward node receive the longer delayed feedback information on the impending congestion, the switch can be already congested from the uncontrolled arriving traffic and the fluctuation of queue length can be inefficiently high in the continuing time intervals. The feedback control method proposed in this paper predicts the queue length in the switch using the slope of queue length prediction function and queue length changes in time-series. The predicted congestion information is backward to the node. NLMS and neural network are used as the predictive control functions, and they are compared from performance on the queue length prediction. Simulation results show the efficiency of the proposed method compared to the feedback control method without the prediction. Therefore, we conclude that the efficient congestion and stability of the queue length controls are possible using the prediction scheme that can resolve the problems caused from the longer delays of the feedback information.