• 대한물리의학회지
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• 제8권3호
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• pp.425-431
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• 2013

PURPOSE: The purpose of this study was to examine the effect of visual control on gait speed and balance in patients with stroke. Static balance and gait speed were investigated with comparison and fixed direction of visual. METHODS: We included twenty-six patients with stroke. Participants were measured static balance while standing on a forceplate with one of 4 different visual direction in front, floor, non-affected side and affected side for 30 seconds. To compare of the gait speed, participants had to walk with one of fixed visual direction. And to compare of gait speed with visual dispersion, gait speed were measured with visual change in left and right, up and down direction every 5m, 2m and 1m intervals. RESULTS: The result of the static balance with fixed visual showed that the affected side and the non-affected side were shown significantly increased sway of total sway length, mediolateral distance, anteroposterior distance, average velocity(p<.05). The gait speed with fixed visual showed that affected side was significantly slower(p<.05). And the gait speed significantly increased as interval of visual dispersion decrease in the sagittal and horizontal plane(p<.05). CONCLUSION: The results from this study showed that the visual direction effected on static balance and the faster visual movement made to increase the gait speed. Therefore the rehabilitation training with visual control may be implemented for stroke patients.

• 충청수학회지
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• 제34권1호
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• pp.37-53
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• 2021

In this paper we define scaled visual curvature and visual Frenet frame that can be visually accepted for discrete space curves. Scaled visual curvature is relatively simple compared to multi-scale visual curvature and easy to control the influence of noise. We adopt scaled minimizing directions of height functions on each neighborhood. Minimizing direction at a point of a curve is a direction that makes the point a local minimum. Minimizing direction can be given by a small noise around the point. To reduce this kind of influence of noise we exmine the direction whether it makes the point minimum in a neighborhood of some size. If this happens we call the direction scaled minimizing direction of C at p ∈ C in a neighborhood Br(p). Normal vector of a space curve is a second derivative of the curve but we characterize the normal vector of a curve by an integration of minimizing directions. Since integration is more robust to noise, we can find more robust definition of discrete normal vector, visual normal vector. On the other hand, the set of minimizing directions span the normal plane in the case of smooth curve. So we can find the tangent vector from minimizing directions. This lead to the definition of visual tangent vector which is orthogonal to the visual normal vector. By the cross product of visual tangent vector and visual normal vector, we can define visual binormal vector and form a Frenet frame. We examine these concepts to some discrete curve with noise and can see that the scaled visual curvature and visual Frenet frame approximate the original geometric invariants.

• 한국철도학회논문집
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• 제8권4호
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• pp.330-336
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• 2005

This paper presents a development of the control and the virtual reality visual system for a tilting train simulator. The user of the tilting train simulator is able to set up the environmental and operating conditions through the user interface provided by the control system. In the control system, an arbitrary track which has user-defined curve radius, length and direction can be generated. The virtual reality visual system provides an artificial environment that is composed of several facilities such as station, platform, track, bridge, tunnel and signaling system. In order to maximize the reality, all of the 3D modeling were based on the real photographs taken in the Jungang line. A dome screen with 1600mm diameter was used to maximize the view angle. The hemispherical screen can ensure the view angle of the 170 degrees of vertical direction and 135 degrees of lateral direction.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.1121-1125
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• 2003

In this paper we deal with visual servoing that can control a robot arm with a camera using information of images only, without estimating 3D position and rotation of the robot arm. Here it is assumed that the robot arm is calibrated and the camera is uncalibrated. We use a pinhole camera model as the camera one. The essential notion can be show, that is, epipolar geometry, epipole, epipolar equation, and epipolar constrain. These play an important role in designing visual servoing. For easy understanding of the proposed method we first show a design in case of the calibrated camera. The design is constructed by 4 steps and the directional motion of the robot arm is fixed only to a constant direction. This means that an estimated epipole denotes the direction, to which the robot arm translates in 3D space, on the image plane.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.23.2-23
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• 2001

In this paper we deal with visual servoing that can control a robot arm with a camera using information of images only, without estimating 3D position and rotation of the robot arm. Here it is assumed that the robot arm is calibrated and the camera is uncalibrated. We use a pinhole camera model as the camera one. The essential notion can be show, that is, epipolar geometry, epipole, epipolar equation, and epipolar constrain. These play an important role in designing visual servoing. For easy understanding of the proposed method we first show a design in case of the calibrated camera. The design is constructed by 4 steps and the directional motion of the robot arm is fixed only to a constant direction. This means that an estimated epipole denotes the direction, to which the robot arm translates in 3D space, on the image plane.

• The Journal of Korean Physical Therapy
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• 제19권6호
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• pp.37-41
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• 2007

Purpose: Hemiplegic patients usually present with difficulties in maintaining their balance. Balance retraining is a major component of a rehabilitation program for patients with neurological impairments. This study compared the effects of prorpioceptive exercise and visual feedback program on the limits of stability (LOS) in chronic hemiplegia patients. Methods: Thirty subjects (mean age $57.0{\pm}9.8$) were recruited. The subjects were divided into a proprioceptive group and a visual group. The subjects for the proprioceptive group participated in the proprioceptive exercise program for 4 weeks, and the visual group were treated with visual feedback training using a Balance Master. Results: At the 4 week follow-up test, the LOS in the proprioceptive group improved significantly in all directions (p<0.05). However, improvement was only observed in the forward direction in the visual feedback group. Therefore, the proprioceptive control approach improves the LOS in chronic hemiplegia patients. Conclusion: These results suggest that compared with physical therapy alone using a proprioceptive control approach to hemiplegia, there was no additional benefit of visual feedback training, such as Balance Master, when administrated in combination with other physical therapy interventions.

• Ocean Systems Engineering
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• 제7권1호
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• pp.39-51
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• 2017

Fishes detect various sensory stimuli, which may be used to direct their behavior. Especially, the visual and water flow detection information are critical for locating prey, predators, and school formation. In this study, we examined the specific role of these two different type of stimulation (vision and vibration) during the obstacle avoidance behavior of carp, Cyprinus carpio. When a visual obstacle was presented, the carp efficiently turned and swam away in the opposite direction. In contrast, vibration stimulation of the left or right side with a vibrator did not induce strong turning behavior. The vibrator only regulated the direction of turning when presented in combination with the visual obstacle. Our results provide first evidence on the innate capacity that dynamically coordinates visual and vibration signals in fish and give insights on the novel modulation method of fish behavior without training.

• International Journal of Automotive Technology
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• 제7권1호
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• pp.35-41
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• 2006

Driving simulations were performed to evaluate the effect of providing both visual information and body sensory information on changes in steering characteristics and the amount of perspiration in drift cornering. When the driver is provided with body sensory information and visual information, the amount of perspiration increases and the driver can perform drift control with a moderate level of tension. With visual information only, the driver tends to easily go into a spin because drift control is difficult. In this case, the amount of perspiration increases greatly as compared with the case where body sensory information is also provided, reflecting a very high perception of risk. When body sensory information is provided, the driver can control drift adequately, feeding back the roll angle information in steering. The importance of the driver's perception of the state of the vehicle was thus confirmed, and a desirable future direction for driver assistance systems was determined.

• 한국콘텐츠학회논문지
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• 제10권9호
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• pp.285-292
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• 2010

본 연구는 8방향 경사와 회전운동이 만성요통환자의 통증과 동적균형에 미치는 영향을 알아보고자 시행되었다. 20명의 만성요통환자가 실험에 참여하였다. 10명(실험군)은 물리치료기구[온열팩{Hot Pack(H/P), 경피신경자극{Transcutaneous Electric Nerve Stimulation(TENS)}, 초음파{Ultra Sound(U/S)}]를 이용한 치료를 받은 후에 8방향 경사와 회전운동을 실시하였고 나머지 10명(대조군)은 물리치료기구를 이용한 치료만 실시되었다. 치료 중재는 주 3회, 6주 동안 적용되었다. 동적균형과 통증은 Star Excursion Balance Test(SEBT)과 Visual Analog Scale(VAS)를 이용하여 측정하였다. VAS 점수는 두 그룹 모두 감소하였으나 실험군에서 보다 유의하게 감소하였다. 동적균형 능력 또한 실험군에서 보다 유의한 증가를 나타내었다. 따라서 8방향 경사와 회전운동은 만성요통환자의 통증과 동적균형에 효과가 있었다고 사료된다.

• 한국정보기술응용학회:학술대회논문집
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• 한국정보기술응용학회 2005년도 6th 2005 International Conference on Computers, Communications and System
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• pp.113-117
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• 2005

This paper describes a visual control scheme, fuzzy logic system for visual servoing of an autonomous mobile robot. An existing communication autonomous mobile robot always needs to keep the object in image to detect the moving object. This is a problem in an autonomous mobile robot for spontaneous activity. To solve it, some features for an object are taken from an image and then use in the design of fuzzy logic system for decision of moving location and direction of visual servoing contrivance(apparatus). So continuous tracking is possible by moving the visual servoing contrivance. We present some simulation results and further studies in the Section of Simulation and Concluding Remarks.