• 한국전문물리치료학회지
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• 제4권3호
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• pp.34-44
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• 1997

The purpose of this study was to compare the balance ability at different foot angle with KAT 2000 (Breg, Inc., Vista, CA. 1994). Forty-nine (male 24, female 25) normal subjects participated in this study. All subjects were assessed under two conditions. One was eye-opened condition and the other one was eye-closed one in 3 psi surface condition. All subjects were tested at different foot angle that were toe-in $25^{\circ}$, $45^{\circ}$, toe-out $25^{\circ}$ and $45^{\circ}$. The subject attempted to keep the platform as stable as possible with eyes closed and with eyes opened for every 20 seconds. The starting position was that subject crossed their arms across chest and flexed knees slightly. The results of each test were showed by a score on screen, which meant balance index. The se collected data were analyzed by using oneway ANOVA, Scheffe test, and t-test. The results of this study were as follows: 1. When the foot angle were changed, balance index was the lowest in toes-out $25^{\circ}$ condition and greatest with toes-in $45^{\circ}$ with eyes opened and with eyes closed. There were statistically significant difference with eyes opened and with eyes closed (p<0.05). 2. There was statistically significant difference in balance index according to visual condition and the balance index tested with eyes closed was higher than with eyes closed(p<0.05). 3. There was statistically significant difference in balance index by gender(p<0.05).

• 한국철도학회논문집
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• 제11권2호
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• pp.126-138
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• 2008

논문은 CDMA(Code Division Multiple Access)기반의 mobilePOST SMSC(Short Message Service Center) 플랫폼에서 고성능 단문메시지 처리를 위한 향상된 메시지 저장 기법에 관한 것이다. 본 논문에서 제 안한 메시지 저장 방법은 i)단문 메시지의 전송 성능을 극대화하기 위하여 시스템 내부 프로세스들간에 공유 메모리 방식을 이용하였고, ii)시스템이 불안정하거나 초기화되었을 때 분실될 가능성이 있는 공유메모리에 존재하는 단문메시지를 파일 시스템에 복사하고 또한 iii)단문메시지의 전송이 완료된 후 과금처리 및 기타 관리를 위하여 공유메모리에 존재하는 단문메시지를 관계형 데이터베이스로 저장하는 3가지 방식을 사용하였다.

• 한국지능시스템학회논문지
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• 제22권1호
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• pp.69-74
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• 2012

본 논문에서는 무게중심 변동이 존재하는 차륜형 역진자가 경사면을 주행하는 경우에 대한 일반적인 운동방정식이 유도되었고 기존 역진자와의 차별점들이 고찰되었다. 차륜형 역진자는 점유면적이 작은 특성 때문에 협소한 장소에서 운용되는 다양한 분야에서 이동 플랫폼으로 채용되고 있다. 차륜형 역진자는 기존 역진자의 불안정한 특성을 그대로 계승하고 있으며, 넘어지지 않고 직립하게 위해서 지속적인 제어가 실행되어야 한다. 차륜형 역진자용 고성능 제어기를 설계하기 위해서는 다양한 환경과 운용조건에서 동작하는 차륜형 역진자를 대상으로 하는 운동방정식과 그 특성을 고려하는 것은 필수적이다.

• International Journal of Advanced Culture Technology
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• 제4권4호
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• pp.81-86
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• 2016

In this paper, we propose a simple and effective vision-based tracking controller design for autonomous object tracking using multicopter. The multicopter based automatic tracking system usually unstable when the object moved so the tracking process can't define the object position location exactly that means when the object moves, the system can't track object suddenly along to the direction of objects movement. The system will always looking for the object from the first point or its home position. In this paper, PID control used to improve the stability of tracking system, so that the result object tracking became more stable than before, it can be seen from error of tracking. A computer vision and control strategy is applied to detect a diverse set of moving objects on Raspberry Pi based platform and Software defined PID controller design to control Yaw, Throttle, Pitch of the multicopter in real time. Finally based series of experiment results and concluded that the PID control make the tracking system become more stable in real time.

• Nuclear Engineering and Technology
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• 제53권4호
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• pp.1088-1099
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• 2021

Time-frequency analysis technique is an effective analysis tool for non-stationary processes. In the field of reactor neutron noise, the time-frequency analysis method has not been thoroughly researched and widely used. This work has studied the time-frequency analysis of the reactor neutron noise experimental signals under bubble disturbance and control rod vibration. First, an experimental platform was established, and it could be employed to reactor neutron noise experiment and data acquisition. Secondly, two types of reactor neutron noise experiments were performed, and valid experimental data was obtained. Finally, time-frequency analysis was conducted on the experimental data, and effective analysis results were obtained in the low-frequency part. Through this work, it can be concluded that the time-frequency analysis technique can effectively investigate the core dynamics behavior and deepen the identification of the unstable core process.

• 대한물리치료과학회지
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• 제29권2호
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• pp.20-27
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• 2022

Background: The purpose of the present study was to determine whether balance training combined with light touch improves the postural sway and gait speed in stroke patients. Design: Randomized Controlled Trial Study Methods: The current study included 40 stroke patients, who were randomly divided into two groups: the balance training with light touch (LT) group (n=20) and the balance training with heavy touch (HT) group (n=20). Both groups performed balance training on a stable and unstable ground. Additionally, the LT group provided light touch stimulation, and the HT group provided heavy touch stimulation. All the participants underwent 20 sessions of STS training (thirty minutes, five days per week for four weeks). In this study, postural sway was measured using a force platform, and walking speed was measured using a 10 meter walk test. Results: The improvements in postural sway and gait speed were observed to be significantly greater in the LT group, compared to the HT group (p<0.05). Conclusion: The results of the current study imply that balance training combined with light touch is a beneficial and effective therapeutic modality that can be employed to improve the postural sway and gait speed in stroke patients.

• 한국운동역학회지
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• 제17권4호
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• pp.17-25
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• 2007

The purpose of the study is to give basic data for the improvement of the skill and to show an exemplary position for squash club members or trainers thru a comparative analysis on the kinematics and kinetics variables on the forehand drive motion in playing squash. The objects of the research are divided into two sections, skilled group(n=8) and unskilled group(n=8). The skilled group is composed of professional players currently working and unskilled group is career of six month, both of lives in B city. In this research, to gather the data 3D motion analysis and test result analysis using force platform was used. The variables are duration, position, segment velocity, segment acceleration and etc. in using force platform. The results are as follows: 1. The duration per phase of the skilled is 0.18sec P1(DS) while that of unskilled is 0.32sec. in P2(FT), the duration of the skilled is 0.29sec, that of unskilled is 0.34sec. Average of the duration of the skilled is 0.48sec, while the unskilled, 0.66sec. 2. Regarding positional movements per event, the unskilled has a relatively higher position in center of gravity, shoulder joint, elbow joint compared with that of the skilled. Generally speaking, positions of the unskilled is higher than the skilled. 3. In segment velocity per event, R-shank, R-upper arm, R-forearm and racket. The skilled is faster than the unskilled. we found a big dig difference in shank. 4. In acceleration per event, there was a big difference in upper-arm and fore-arm of the impact. 5. The skilled group on the force platform shows relatively stable and regular changes while the unskilled shows unstable from the touch down to initial 20% the force value of central support period after the impact moment decreases rapidly and the center of gravity is not moved well. 6. The maximum force value of the skilled is 1019.7N. it is found 19.86% of the total duration. That of the unskilled is 639.2N, it is found 20.67% of total duration.

• 대한의용생체공학회:의공학회지
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• 제28권5호
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• pp.628-635
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• 2007

We studied the effect of vibratory stimulations of different leg muscles, tibialis anterior(TA) and triceps surae(TS), and plantar zones in ten healthy subjects during 1) quiet standing, 2) forward lean of body, 3) backward lean of body, 4) right lean of body, and 5) left lean of body. The experiments were performed on the force platform. The effect of vibration were measured by monitoring the area of COP(Center of pressure) sway. The subjects wore a vibratory stimulation system on foot and ankles and were given the instruction not to resist against the applied perturbations. The results show that all vibratory stimulations to lower limb muscles and plantar zones reduced the COP sway area. This reduction of the COP sway area occurred also in partial vibratory stimulations during quiet standing. In forward lean of body, vibratory stimulations to TA reduced the COP sway area. During backward lean of body, vibratory stimulations to TS reduced the COP sway area. When the subject was tilted right, vibratory stimulations to left plantar zone reduced the COP sway area. During left lean of body, vibratory stimulations to right plantar zone reduced the COP sway area. Thus, the influence of vibratory stimulations to leg muscle and plantar zones differed significantly depending on the lean of body. We suggest that the vibration stimuli from leg muscles and plantar zones could be selectively used to help maintaining postural balance stable.

• 한국인터넷방송통신학회논문지
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• 제17권1호
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• pp.145-151
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• 2017

본 논문은 선박 평형수 처리 시스템에서 여러 센서 장치들이 원격으로 전송한 데이터 특성을 토대로 장치의 고장 예측과 목적지 운항경로 상의 수리지점 대상 가장 효율적인 지점 선정 및 수리 예약하는 시스템의 설계 및 구현을 제시하였다. 이러한 데이터는 선박에 평형수를 채우거나 비울 시에 실시간으로 수집되며, 정상과 비정상의 테이타 특성을 분석하여 비 안정적 특성을 보이는 장치에 대한 사전 수리가 필수적이다. 선박이 다음 목적지를 향한 항로 운항 중 이네비게이션을 기반한 가장 효율적인 수리 센터를 선택하여 예약하는 고장 예측 및 수리 예약을 위한 소프트웨어 플랫폼을 제시하였다. 본 시스템의 적용은, 해양 오염 방지를 위한 IMO의 협약이 2017년도에 발표됨에 따라, 선박들의 안정적인 입출항과 해양 생태계 보호하며, 또한 안정적 화물 운항으로 인한 경제적 효과가 매우 높다.

• 한국산학기술학회논문지
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• 제16권11호
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• pp.7941-7948
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• 2015

열차 운행시에 발생하는 전동소음은 열차 차륜과 레일 표면조도의 불균일성에 의하여 가진된 진동에 의해 발생된다. 따라서 열차 전동소음의 전달, 예측 및 분석을 위해서는 차륜과 레일표면의 음향조도(acoustic roughness)의 정확한 측정과 분석이 필요하다. 그러나 현재의 레일표면의 조도측정을 위한 장치와 방법은 작업자의 수작업에 의존한 트롤리 장치를 사용함으로써, 불일정한 측정속도와 흔들림과 같은 불안정한 인터페이스를 야기하여 측정값의 오차와 외란을 증대시키는 단점을 지닌다. 본 논문은 철도궤도의 레일상에서 자율 정속 주행하면서 레일표면의 음향조도를 측정하는 자동화 측정장치 및 플랫폼을 개발함으로써, 측정정밀도를 향상시키고 측정값의 불균일성을 감소시켰다. 또한 측정값의 신뢰도와 정확도 향상을 위해 동일한 복수의 변위센서 적용법을 제안하였으며 표준레일구간의 현장측정을 통해 동일 변위센서로부터 융합된 데이터의 정확성을 검증하였다.