• Journal of the Institute of Electronics Engineers of Korea SP
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• v.48 no.6
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• pp.105-114
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• 2011

The snake algorithm is widely adopted to track objects by extracting the active contour of the object from background. However, it fails to track the target converging to the background if there exists background whose gradient is greater than that of the pixels on the contour. Also, the contour may shrink when the target moves fast and the snake algorithm misses the boundary of the object in its searching window. To alleviate these problems, we propose an improved algorithm that can track object contour more robustly. Firstly, we propose two external energy functions, the edge energy and the contrast energy. One is designed to give more weight to the gradient on the boundary and the other to reflect the contrast difference between the object and background. Secondly, by computing the motion vector of the contour from the difference of the two consecutive frames, we can move the snake pointers of the previous frame near the region where the object boundary is probable at the current frame. Computer experiments show that the proposed method is more robust to the complicated background than the previously known methods and can track the object with fast movement.

• Journal of Biomedical Engineering Research
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• v.28 no.2
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• pp.218-228
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• 2007

Modem concepts of gait rehabilitation after stroke favor a task-specific repetitive approach. In practice, the required physical effort of the therapists limits the realization of this approach. Therefore, a mechanized gait trainer enabling nonambulatory patients to have the repetitive practice of a gait-like movement without overstraining therapists was constructed. In this study, we developed an active gait training system for patients with gait disorder. This system provides joint movements to patients who cannot carry out an independent gait. It provides a normal stance-swing ratio of 60:40 using an eccentric configuration of two gears. Joint motions of the knee and the ankle were evaluated with using the 3D motion analysis system and compared with the results from the multi-body dynamics simulation. In addition, clinical investigations were also performed for low stroke patients during the 6-week gait training. Results from the dynamics simulation showed that joint movements of the knee and the ankle were affected by the gear size, the step length and the length of the foot plate, except the radius of curvature of the foot guide plate. Also, the 6-week gait training revealed relevant improvements of the gait ability in all low subjects. Functional ambulation category levels of subjects after training were 2 in three patients and 1 in a patient. The developed active gait trainer seems feasible as an adjunctive tool in gait rehabilitation after stroke.

• Physical Therapy Korea
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• v.21 no.2
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• pp.57-66
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• 2014

The objective of this study was to determine the duration of maintained calf muscle flexibility gained in young adults with calf muscle tightness, as measured by increases in ankle active and passive dorsiflexion range of motion (DFROM) after three stretching interventions. Twenty subjects (5 men and 15 women) with calf muscle tightness received the following three stretching interventions in one leg (assigned at random): static stretching (SS), eccentric training on stable surface (ETS), and eccentric training on unstable surfaces (ETU). The subjects received all three interventions to the same leg, applied in a random order. Each intervention had a break of at least 24 h in-between, in order to minimize any carryover effect. Each intervention used two types of stretching: with the calf muscle stretched and both knees straight, and with the knee slightly bent in order to maximize the activation of the soleus muscle. All three interventions were performed for 200 seconds. We measured the duration of maintained calf muscle flexibility through active and passive ankle DFROM before intervention, immediately after intervention (time 0), and then 3, 6, 9, 15, and 30 min after intervention. We found a difference in the duration of maintained calf muscle flexibility between the three interventions. In the ETS and ETU interventions, a significant improvement in calf muscle flexibility, both ankle active and passive dorsiflexion ranges of motion (ADFROM and PDFROM), was maintained for 30 min. In the SS intervention, however, ADFROM before 9 min and PDFROM before 6 min were statistically different from the baseline. Our results suggest that ETS and ETU may be more effective than SS for maintaining calf muscle flexibility in young adults.

• Journal of the Korean Society of Physical Medicine
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• v.13 no.2
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• pp.129-135
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• 2018

PURPOSE: The imbalance of pretibial muscles can be a factor contributing to the development of pes planus. However, no study has yet compared the muscle activity of the tibials anterior (TA) to that of the extensor digitorum longus (EDL). The purpose of this study was to determine whether there are differences in the electromyographic (EMG) TA and EDL amplitude indexes (AIs) between normal and pes planus feet. METHODS: A total of 14 subjects with normal feet and 15 subjects with bilateral pes planus participated in this study. TA and EDL muscle activities were measured using a wireless EMG system and the angles of ankle dorsiflexion and eversion of the subtalar joint were measured using a universal goniometer during active ankle dorsiflexion in the prone position. AI was calculated as follows: $\text{amplitude_{TA}-amplitude_{EDL}/(amplitude_{TA}+amplitude_{EDL})}/2{\times}100$. RESULTS: The AIs of the TA and EDL were significantly lower in pes planus feet than in normal feet (p<.05). The angle of subtalar eversion was significantly greater in pes planus feet than in normal feet during active ankle dorsiflexon (p<.05). However, there was no significant difference in the angle of ankle dorsiflexion between normal feet and pes planus feet (p>.05). CONCLUSION: This study showed that TA muscle activation was lower in pes planus feet than in normal feet, resulting from greater eversion range of motion during active ankle dorsiflexion. We suggest that the imbalance of ankle dorsiflexors must be considered in pes planus management.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.23 no.2
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• pp.9-16
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• 2017

Background: The purpose of this study was to investigate the relationship between the spine and the flat-foot, the stability and the alignment of the posture of the neck to prevent the alignment of the ankle joint operation and the lower back flexibility of the lumbar region according to the type of treatment using active stretching of the triceps, back pain, and to see how they affect weight bearing differences. Methods: The subjects of this study were 24 chronic low back pain patients. They were randomly divided into experimental group and control group. In the experimental group, ankle joint mobilization and active scraping of triceps were performed three times a week for a total of 6 weeks. The control group was performed in the same way without articulation. The range of flexion and extension motion of the lumbar spine and pain degree and difference of weight-bearing were measured before and after the experiment. Results: The model of ankle joint mobilization and calf muscle elongation of flat foot significantly improved the range of flexion and extension motion of the vertebrae (p<.05) and the VAS and distribution of weight-bearing were decreased in both of two groups (p<.05). In other words, the exercise and mobilization help to recover of the balance of the whole musculoskeletal, the vertebrae. Conclusions: The active exercise of the triceps muscle of the lower leg in this study It affects the flexibility of the lumbar spine, the pain and the difference in the weight support of the lower extremities, when we performed ankle joint mobilization for exercise and cramping, pain and the difference in weight support between the two lower limbs.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.1015-1017
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• 2013

Object tracking, in general, is a challenging problem. Difficulties in tracking objects can arise due to abrupt object motion, changing appearance patterns of both the object and the scene, non-rigid object structures, object-to-object and object-to-scene occlusions, and camera motion. Tracking is usually performed in the context of higher-level applications that require the location or the shape of the object in every frame. This paper describes an object tracking system based on active vision with two cameras, into algorithm of single camera tracking system an object active visual tracking and object locked system based on Extend Kalman Filter (EKF) is introduced, by analyzing data from which the next running state of the object can be figured out and after the tracking is performed at each of the cameras, the individual tracks are to be fused (combined) to obtain the final system object track.

• Clinics in Shoulder and Elbow
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• v.25 no.4
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• pp.311-320
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• 2022

Background: The outcomes of patients 50-55 years old or younger undergoing prosthetic shoulder arthroplasty (PSA) may not generalize to younger patients. We report outcomes following PSA in a consecutive series of patients 40 years or younger. We hypothesize that total shoulder arthroplasty (TSA) provides better outcome and durability than resurfacing hemiarthroplasty (RHA). Methods: Patients were stratified by diagnosis and surgical procedure performed, RHA or TSA. Active range of motion and self-assessed outcome were evaluated preoperatively and at final follow-up. Results: Twenty-nine consecutive PSAs were identified in 26 patients, comprising 9 TSAs and 20 RHAs, with a minimum of 2-year follow-up. Twelve PSAs were performed for chondrolysis. Mean active forward elevation, abduction, external rotation, and internal rotation improved significantly (p<0.001 for all). Mean pain score improved from 6.3 to 2.1, Simple Shoulder Test from 4.0 to 9.0, and American Shoulder and Elbow Surgeons score from 38 to 75 (p<0.001 for all). Patients undergoing RHA and TSA had similar outcomes; but three RHAs required revision, two of these within 4 years of implantation. Four of five patients undergoing revision during the study period had an original diagnosis of chondrolysis. Conclusions: PSA in young patients provides substantial improvement in active range of motion and patient reported outcomes irrespective of diagnosis and glenoid management. However, patients undergoing RHA, especially for chondrolysis, frequently require subsequent revision surgery, so that RHA should be considered with caution in young patients and only after shared decision-making and counsel on the risk of early revision to TSA.

• Journal of Convergence for Information Technology
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• v.12 no.2
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• pp.174-183
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• 2022

This study was conducted to investigate the effect of the active exercise program using sling on the pain and balance of total knee replacement patients. Subjects were 20 patients who received total knee replacement and are hospitalized, 10 patients in each group were randomly assigned to a group (CPM group) that applied only CPM (Continuous passive motion) and a group (CSG) that combined CPM with a active exercise program using sling. CG was performed CPM 5 days a week, CSG performed CPM 2 days a week and a active exercise program using sling 3 days a week, and each intervention was performed for 40 minutes a day for a total of 4 weeks. Pain was evaluated using VAS (Visual analog scale), and balance was measured using BT4 (Balance training 4) to measure C90 area, trace length, and Sway average velocity with eyes open and closed. As a result, there was a significant decrease in pain in both groups, and there was also a significant difference in the amount of change between groups. In balance, all variables except C90 of CG showed significant changes after intervention, and there was a significant difference between C90 and Vel with eyes closed in the amount of change between groups. Therefore, we believe that CPM and active exercise program using sling are effective interventions to reduce pain and improve balance in total knee replacement patients.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.2 s.233
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• pp.188-200
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• 2005

Control of a multi-fingered robotic hand is usually based on the theoretical analysis for kinematics and dynamics of fingers and of object. However, the implementation of such analyses to robotic hands is difficult because of errors and uncertainties in the real situations. This article presents the control method for estimating the kinematic constraint of an unknown object by active sensing. The experimental system has a two-fingered robotic hand suspended vertically for manipulation in the vertical plane. The fingers with three degrees-of-freedom are driven by wires directly connected to voice-coil motors without reduction gears. The fingers are equipped with three-axis force sensors and with dynamic tactile sensors that detect slippage between the fingertip surfaces and the object. In order to make an accurate estimation for the kinematic constraint of the unknown object, i.e. the constraint direction and the constraint center, four kinds of the active sensing and feedback control algorithm were developed: two position-based algorithms and two force-based algorithms. Furthermore, the compound and effective algorithm was also developed by combining two algorithms. Force sensors are mainly used to adapt errors and uncertainties encountered during the constraint estimation. Several experimental results involving the motion of lifting a finger off an unknown object are presented.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.123-128
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• 2005

A novel tri-mode ultraprecision positioning system for machine tools and measuring machine is proposed. The basic coarse mode uses a Twist-roller Friction Drive (abbr. TFD), and controls several tens of millimeters of the machine-table travel with nanometer order of positioning resolution. The fine mode also utilizes the TFD with a fine adjusting mechanism. The resolution of the fine mode is in the range of sub-nanometer. For realizing picometer positioning, the ultra-fine mode is executed by using an active aerostatic guideway. On the bearing surface of this active guideway, several Active Inherent Restrictors (abbr. AIRs) are embedded for controlling the table position. An AIR unit consists of a piezoelectric actuator having a through hole, one end of the hole on the bearing surface acts as an inherent restrictor. Owing to the aerostatic mechanism of the AIR, the deformation of the piezoelectric actuator in the AIR unit causes much reduced table displacement. Such motion reduction is effective for ultraprecision positioning. Current positioning resolution of the ultra-fine mode is 50pm, however the final goal of the positioning resolution is expected to be in the order of picometer.