• Proceedings of the ESK Conference
• /
• 1997.10a
• /
• pp.359-365
• /
• 1997

When grasping a movable object or making an object move, humans feel kinesthetic sense. Kinesthetic sense is the human sense that the human feels in response to the motion acted on the human. The objecive of the paper is tranforming the kinesthetic sense to quantitized data that is useful from the viewpoint of engineering. To provide various motion patterns, 2-dimensional motion generator was built using 2-axis linear motors. Active stiffness and active damping were implemented by means of current control and force feedback techniques. Based on Taguchi method, the most dominant factors to affect kinesthetic sense were investigated. Also, some functions adequate to quantize the kinesthetic sense were found.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2008.04a
• /
• pp.71-76
• /
• 2008

This paper is concerned with the active vibration control of elevator by means of the active roller guide. To this end, a dynamic model for the horizontal vibration of the elevator consisting of a supporting frame, cage and active roller guides was derived using the energy method. Free vibration analysis was then carried out based on the equations of motion. Active vibration controller was designed based on the equations of motion using the LQR theory and applied to the numerical model. Rail irregularity and wind pressure variation were considered as external disturbance in the numerical simulations. The numerical results show that the active vibration control of elevator is possible.

• Proceedings of the Korean Society of Broadcast Engineers Conference
• /
• 2009.01a
• /
• pp.714-718
• /
• 2009

3D reconstruction of a human face from an image sequence remains an important problem in computer vision. We propose a method, based on a factorization algorithm, that reconstructs a 3D face model from short image sequences exhibiting rotational motion. Factorization algorithms can recover structure and motion simultaneously from one image sequence, but they usually require that all feature points be well tracked. Under rotational motion, however, feature tracking often fails due to occlusion and frame out of features. Additionally, the paucity of images may make feature tracking more difficult or decrease reconstruction accuracy. The proposed 3D reconstruction approach can handle short image sequences exhibiting rotational motion wherein feature points are likely to be missing. We implement the proposal as a reconstruction method; it employs image sequence division and a feature tracking method that uses Active Appearance Models to avoid the failure of feature tracking. Experiments conducted on an image sequence of a human face demonstrate the effectiveness of the proposed method.

• Journal of information and communication convergence engineering
• /
• v.2 no.1
• /
• pp.52-57
• /
• 2004

In this paper, we propose a panorama-based object tracking scheme for wide-view surveillance systems that can detect and track moving objects with a pan-tilt camera. A dynamic mosaic of the background is progressively integrated in a single image using the camera motion information. For the camera motion estimation, we calculate affine motion parameters for each frame sequentially with respect to its previous frame. The camera motion is robustly estimated on the background by discriminating between background and foreground regions. The modified block-based motion estimation is used to separate the background region. Each moving object is segmented by image subtraction from the mosaic background. The proposed tracking system has demonstrated good performance for several test video sequences.

• Journal of Korean Physical Therapy Science
• /
• v.1 no.1
• /
• pp.145-163
• /
• 1994

This study was done to determine differences in effect of postoperative pain control in patients receiving auricular electroacustimulation vs transcutaneous electrical nerve stimualtion following total knee replacement surgery. Thirty-one cases referred to physical therapy department after treated by total knee replacement surgery by orthopedic surgery department at the Pohang St. Mary's Hospital from January 1993 through June 1994. Of 31 total knee replacement cases, 13 cases were auricular electroacustimulation group, 11 cases were transcutaneous electrical nerve stimulation group, and 7 cases were control group. The results of the study summerized are as follows: Thirty-one total knee replacement cases(male in 12 cases, female in 19 cases), ranging in age from 34 to 61 years(mean${\pm}$SD=49.90 7.56) with diagnoses of degenerative arthritis(20 cases), rheumatoid arthritis(9 cases), and other(2 cases). In auricular electroacustimulation group, there was a significant change of pain intensity, unpleasantness, and active range of motion after treatment(p<0.01). In transcutaneous electrical nerve stimulation group, there was a significant change of pain intensity, unpleasantness, and active range of motion after treatment(p<0.01). In control group, did not show significant pre-posttreatment differences in pain intensity, unpleasantness, active range of motion(p>0.05). The mean change in pain intensity and unpleasantness, active range of motion from pretreatment baseline for the 3 groups. Auricular electroacustimulation group showed the large magnitude of increase in pain intensity and unpleasantness, active range of motion when compared to its own pretreatment cycle. Transcutaneous electrical nerve stimulation group showed small magnitude of increase in pain intensity and unpleasantness, active range of motion when compared to its own pretreatment cycle. No significant changes were observed in control group. Highly significant differences in pain intensity, unpleasantness, and active rage of motion were found using an ANOVA measures between treatment groups and control group(p<0.01). The squares correlation coefficients of pain and function measures pretreatment-posttreatment differences for each group. In treatment group, there was significant correlation between pain scale and function(p<0.001). In control group, there was no correlation between the pain scale and function (p>0.05). The continuous study is needd for many interesting issues of auricular electroacustimulation in new future.

• Journal of the Korean Society for Precision Engineering
• /
• v.14 no.12
• /
• pp.114-120
• /
• 1997

For compensating the error motion of hydrostatic tables, we have introduced a way that the clearance of table is controlled corresponding to the amount of eror with the actively controlled variable capillary, named as ACC. In previous paper, through the basic test, it was confirmed that by the use of ACC, the error motion within 2.7$\mu$ m of a hydrostatic table could be compensated with the resolution of 27nm, 1/100 contollable range, and with the frequency bandwidth of 5.5Hz, structurally. In this paper, we performed practical compensation of the linear and angular motion error of hydrostatic table using ACC. For improving the compensated motion accuracy, iterative control method is put into the control system. The experimental results show that by the simultaneous compensation of error, the linear and angular motion error are improved upto 0.25$\mu$ m and 0.4arcsec, which are about 1/10 and 1/3 of the non-compensated motion errors respectively.

• Journal of Korean Physical Therapy Science
• /
• v.15 no.4
• /
• pp.27-34
• /
• 2008

Background: This study was designed to analyze Repetitive dorsiflexion exercises in ankles have effects on the active range of flexion and extension motion through lumbar, cervical spine and ankle, wrist joints. Methods: 30 female college students in their twenties who frequently wear high heels participated the number of the experimental group was 15 persons and the number of the control group was 15 persons. They did exercise at the physical therapy room in M college, from the 8th of March to the 11th of April 2007. The experimental group had used the model of dorsiflexion repetitive exercise three times per week, for 4 weeks, but the control group did not exercise at all. In the sagittal plane active ROM of the these spine and joints were measured before and after the experiment using a digital goniometer. The results of two groups were compared and analyzed using paired T-test. Results: The active range of flexion and extension motion of the vertebra(especially lumbar flexion) and distal joints were significantly different in exercise group(p<.05). Conclusion: The model of repetitive dorsiflexion exercise of the ankle joint had positive effects on improving the active range of flexion and extension motion of the lumbar vertebra and distal joints of limbs. The results suggest that the repetitive dorsiflexion exercise is useful and also effective therapy for improving motion in women usually wearing high-heel.

• Journal of the Korean Society for Precision Engineering
• /
• v.26 no.2
• /
• pp.109-117
• /
• 2009

This paper presents a linear air bearing stage with compensated motion errors by active control of preloads generated by magnetic actuators with combination of permanent and electromagnets. A 1-axis linear stage motorized with a linear motor with 240mm of travel range is built for verifying this design concept and tested its performances. The three motions of the table are controlled with four magnetic actuators driven by current amplifiers and a DSP based digital controller. Three motion errors were measured combined method with laser interferometer and two-probe method with $0.085{\mu}m$ of repeatability for straightness error. The measured motion errors were modeled as functions of the stage position, and compensation were carried out with feedforward control because the characteristics of the motion control with magnetic actuators are linear and independent for each degree-of-freedoms. As the results, the errors were reduced from $1.09{\mu}m$ to $0.11{\mu}m$ for the vertical motion, from 9.42 sec to 0.18 sec for the pitch motion and from 2.42 sec to 0.18 sec for roll motion.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.15 no.3 s.96
• /
• pp.364-370
• /
• 2005

The active magnetic bearing (AMB) systems mounted in moving vehicles are exposed to the disturbances due to the base motion, often leading to malfunction or damage as well as inaccurate positioning of the systems. Thus, in the controller design of such AMB systems, robustness to base disturbances becomes an essential requirement. In this study, effective control schemes are proposed for the homo-polar AMB system, which uses permanent magnets for generation of bias magnetic flux, when it is subject to base motion, and its control performance is experimentally evaluated. The base motion of AMB system is modeled as the dynamic disturbances in the gravity and base excitation forces. To effectively compensate for the disturbances, the angle feed-forward controller based on the inverse dynamic model and the acceleration feed-forward controller based on the normalized filtered-X LMS algorithm are proposed. The performance test of the prototype AMB system is carried out, when the system is mounted on rate table. The experimental results show that the performance of the proposed controllers for the AMB system is satisfactory in compensating for the disturbances due to the base motion.

• Journal of the Korean Society for Precision Engineering
• /
• v.14 no.8
• /
• pp.130-136
• /
• 1997

For compensating the error motion of hydrostatic guideways, we introduce a way that the clearance of table is actively controlled corresponding to the amount of error with the variable capillary. The structure and the theoretical design method of active controlled capillary using piezo actuator, named ACC, are proposed in this paper. Basic characteristics such as the maximum controllable range, micro step response and available dynamic bandwidth are tested for confirmation of structural suitability of ACC, and these characteristics are also tested on the table mounted with ACC for verifying the availability. The experimental result showed that by the use of ACC, the error motion within 2.7 .mu. m of a hydrostatic guideway can be compensated with the resolution of 2.7nm, 1/100 contollable range, and the frequency bandwidth of 5.5 Hz. From these results, it is confirmed that the ACC is very effective to improve the motion accuracy of high or ultra precision hydrostatic guideways.