• 제어로봇시스템학회논문지
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• 제17권5호
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• pp.490-498
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• 2011

In this paper, we present a two-stage vision-based approach to detect multi views of pedestrian in road scene images. The first stage is HG (Hypothesis Generation), in which potential pedestrian are hypothesized. During the hypothesis generation step, we use a vertical, horizontal edge map, and different colors between road background and pedestrian's clothes to determine the leg position of pedestrian, then a novel symmetry peaks processing is performed to define how many pedestrians is covered in one potential candidate region. Finally, the real candidate region where pedestrian exists will be constructed. The second stage is HV (Hypothesis Verification). In this stage, all hypotheses are verified by Support Vector Machine for classification, which is robust for multi views of pedestrian detection and recognition problems.

• Journal of Power Electronics
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• 제18권6호
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• pp.1920-1929
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• 2018

In order to provide a source for nine phases suitable for 18-pulse ac to dc power, this paper proposes a new structure for a step-up asymmetrical delta-connected transformer for converting three-phase ac power to nine-phase ac power. The design allows for symmetry between the nine output voltages to improve the power quality of the supply current and to minimize the THD. The results show that this new structure proves the equality between the output voltages with $40^{\circ}-{\alpha}$ and $40^{\circ}+{\alpha}$ phase shifting and produces symmetrical output currents. This result in the elimination of harmonics in the network current and provides a simulated THD that is equal to 5.12 %. An experimental prototype of the step-up asymmetrical delta-autotransformer is developed in the laboratory and the obtained results give a network current with a THD that is equal to 5.35%. Furthermore, a finite element analysis with a 3D magnetic field model is made based on the dimensions of the 4kVA, 400 V laboratory prototype three-phase with three-limb delta-autotransformer with a six-stacked-core in each limb. The magnetic distribution flux, field intensity and magnetic energy are carried out under open-circuit operation or load-loss.

• 대한물리치료과학회지
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• 제10권2호
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• pp.17-28
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• 2003

The aim of this study was to investigate the effects of treadmill gait training on the functional characteristics and the temporal-distance parameters of gait in hemiplegic patients, as compared with conventional gait training. The subjects of this study were 32 hemiplegic patients who had been admitted or were visited out-patients at Kangdong Sacred Heart Hospital, Hallym University, from March 3 through April 25, 2003. These subjects were randomly divided into treadmill gait training group or conventional gait training group. We evaluated the gait ability, motor functions, muscle strength, spasticity, physiological cost index, and temporal-distance parameters. We analyzed the changes between pre and post training in each groups, and the difference between two groups. Temporal-distance parameters were obtained using the ink footprint method and then energy consumption using physiological cost index. The results were as follows: 1. After a six-week training, treadmill gait training group significantly improved, as. compared to pre-training, in gait ability, motor functions for the leg and trunk and gross function, muscle strength of the lower limb, gait speed, cadence, step length both on the affected and on the unaffected side, step length symmetry, and energy consumption(p<0.05). 2. After a six-week training, conventional gait training group significantly improved, as compared to pretraining, in gait ability, motor functions for the leg and trunk, muscle strength of the lower limb, spasticity the upper limb, gait speed, cadence, step length both on the affected and on the unaffected side, and energy consumption(p<0.05). 3. After a six-week training, the treadmill gait training group significantly improved, as compared to the conventional gait, training, in gait speed and step length on the unaffected side. These results show that treadmill gait training was improved gait speed and step length on the unaffected side of hemiplegic patients, as compared with conventional gait training. Further research is needed to confirm the generalization of these findings and to identify which hemiplegic patients might benefit from treadmill gait training.

• 대한물리치료과학회지
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• 제29권3호
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• pp.75-84
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• 2022

Background: This study was to investigate the effect of non-invasive transcranial direct current stimulation due to hemiplegic patients due to stroke on temporal and spatial gait ability. Design: Randomized sham controlled trial. Methods: For the study method, 42 patients with hemiplegia due to stroke were randomly assigned to 14 patients each, and the general walking group, tDCS walking group, and tDCS (sham) walking group were subjected to 5 times a week, 30 minutes a day, and 6 weeks. In the temporal gait variables of hemiplegic patients due to stroke, the effect of the gait time, gait cycle, single support, double support, swing phase, stance phase, gait speed, cadence were measured. In spatial variables, one step length and one step length were measured. Results: As a result of the study, the EG group significantly increased in the step time, gait velocity, and cadence of the paralysis side in the comparison of temporal walking variables between groups according to the application of tDCS of walking ability in hemiplegic patients due to stroke patients(p<.05). In the change in spatial walking variables between groups according to the application of tDCS, the step length and stride length of the EG group showed a significant increase. Both the comparison of temporal and spatial symmetry walking variables between groups according to tDCS application was not significant(p>.05) Conclusion: As a result, tDCS has an effective effect on the improvement of the gait ability of stroke patients. In particular, it is an effective method of physical therapy that can improve the cadence and speed of gait, which can be combined with the existing gait training to effectively increase the gait of hemiplegia due to stroke patients.

• 한국컴퓨터정보학회논문지
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• 제14권12호
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• pp.63-73
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• 2009

본 논문에서는 단순화한 색상 정보에 기반한 컨벌류션 정합(Convolution Matching)을 이용하여 차량을 검출하는 기법을 제안한다. 입력 영상을 화소 색상 벡터의 방향을 고려해 8방향 색상(Red, Green, Blue Cyan, Yellow, Magenta, White, Black)으로 표현한다. 8 방향 색상의 표현은 조명이나 환경 변화에 강인한 영상을 제공한다. 본 논문의 차량 검출 단계는 크게 후보 영역 검출 단계와 차량 검증 단계로 구성된다. 후보 영역 검출 단계에서는 수직 에지와 그림자 등을 고려하여 차량의 후보 영역을 결정한다. 차량 검증 단계에서는 차량을 판별하기 위해 컨벌류션 정합과 후보 영역내의 에지 복잡도를 사용한다. 제안하는 차량 검출 알고리즘은 조명이나 환경이 변화하는 다양한 실험들에서 빠르고 높은 검출률을 보였다.

• 대한물리의학회지
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• 제8권3호
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• pp.351-360
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• 2013

PURPOSE: The purpose of this study was to investigate the effects of observed action gait training on stroke patients. METHODS: 22 subjects were randomized into two groups. The observed action gait training performed that watched a video of normal gait before gait training and the general gait training without watching it. The experimental group(n=11) performed observed action gait training and the control group(n=11) performed general gait training. Both group received gait training for 3 times per week during 8 weeks. RESULTS: The experimental group showed significant differences in the cadence, gait velocity, stride, step, single limb support, double limb support, stride length and step length(p<.05). The control group showed significant differences only in the stride(p<.05). CONCLUSION: The observed action gait training affected coordination and weight shift, as well as symmetry of the body. Plasticity of the brain was facilitated by repetitive visual and sensory stimulation. The observed action gait training promoted the normal gait by watching the normal gait pattern. In conclusion, motor learning through the sensory stimulation promotes brain plasticity that could improve motor function, and observed action gait training indirectly identified stimulated brain activities.

• 한국막학회:학술대회논문집
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• 한국막학회 1997년도 추계 총회 및 학술발표회
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• pp.39-45
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• 1997

Introduction : Polyimides are one of the most important classes of the high performance polymers due to their excellent electrical, thermal, and high-temperature mechanical properties. But their uses are limited because of their poor solubility. Most polyimide derivatives are processed in the form of polyamic acids, which are subsequently converted into the imide structures.Recently, it has been found that the soluble polyimides with large molecular weight sufficient to application. For enhancing processability, the majority of approaches have involved the following factors. As much as, the separation of the imide ring along the back-bone, that is to say, reducing the density of imide ring in the repeat structure. The introduction of bulky substituents along the back-bone, in order to enhance the free volume of main-chain. The incorporation of flexible or thermally stable linkages in the main-chain, reducing the packing force. The disruption of symmetry or recurrence regularity through copolymerization in order to reduce crystallnity.The objectives of this investigation are the synthesis and characterization of soluble polyimides as membrane materials by the single-step polymerization and the preparation of the asymmetric polyimide membrane by using phase inversion technique. In the present study, three series of polyimide derivatives are synthesized; H series is homopolyimides, A series is prepared from single dianhydride and two diamines, B series is yielded from two dianhydrides and a diamine. The dope solution was directly prepared from the PI solution via one step polymerization from monomers.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.3099-3103
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• 2011

In measurement of risk voltages; the step and touch voltage, the distance between the current electrode and the ground electrode recedes up to several hundred meters as the scale of grounding system increases. This paper dealt with the measurement method of risk voltage in a restricted space. The risk voltage was analyzed depending on the distance and the direction of the current electrode from the ground electrode in a $10[m]{\times}10[m]$ mesh grounding system. The average value of risk voltages measured at a point 20 [m] away from the current electrode was deviated below 5 [%] from that measured at 100 [m] point. Consequently, the evaluation of risk voltage of a large-scale grounding system buried in a spatially restricted place is available if the current electrode is installed in symmetry to the ground electrode.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 제13회 신호처리 합동 학술대회 논문집
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• pp.901-904
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• 2000

A direct authentication from gray-scale image, instead of the conventional multi-step preprocessing, is proposed using Gabor filter-based features from the gray-scale fingerprint around core point. The core point is located as a reference point for the translation invariant matching. And its principal symmetry axis is detected for the rotation invariant matching from its neighboring region centered at the core point. And then fingerprint is divided into non-overlapping blocks with respect to the core point and features are directly extracted form the blocked gray level fingerprint using Gabor filter. The proposed fingerprint authentication is based on the Euclidean distance between the corresponding Gabor features of the input and the template fingerprints. Experiments are conducted on 300${\times}$300 fingerprints obtained from a CMOS sensor with 500 dpi resolution, and the proposed method could lower the False Reject Rate(FRR) to 18.2% under False Acceptance Rate(FAR) of 0%.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.458-461
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• 1995

A new type of rotational motor which is developed has a resolution smaller than 10 $^{-4}$ radian and can be accessed for full rotational angles. The operation principle of the motor is based on inchworm motion of two belt driving mechanism. Flexure hinge mechanism, which is pertinent to symmetry construction of the motor, is designed to minimze the effort to frame and is analyzed by using finite element method. Depending on input signal amplitude, rotational angle by one cycle is varied form 0.2*10 $^{-4}$ rad to 9.76* $^{-4}$ rad. This shows that it has the capability of getting very small rotational angle by considering radius of rotor and amplitude of input signal.