• 한국산학기술학회논문지
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• 제21권12호
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• pp.253-260
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• 2020

본 연구는 다양한 좌석 높이에서 일어서기 훈련이 뇌졸중환자의 균형에 미치는 영향에 대해 알아보고자 연구를 실시하였다. 연구의 대상자는 뇌졸중환자 20명이며 무작위로 표준좌석 높이 그룹 10명과 낮아지는 좌석높이그룹 10명으로 분류하여 2019년 3월에서 6월까지 주 3회 6주간 훈련을 실시하였다. 정적균형과 동적균형을 측정하였으며 그룹 내 훈련 전·후의 변화를 검증을 위하여 대응표본 t-검정을 실시하고, 그룹 간 훈련 전·후 변화의 차이를 검증하기 위하여 독립표본 t-검정을 실시하였다. 연구 결과, 그룹 내 훈련 전·후의 변화는 정적균형 및 동적 균형 모두 유의한 변화를 보였으나(p<.05), 그룹 간 훈련 전·후 변화량의 차이는 눈 감은 상태의 선자세 정적균형만 유의한 차이를 보이지 않았다(p>.05). 본 연구의 훈련이 뇌졸중 환자의 균형에 유의한 효과가 있음을 확인하였으며 특히, 훈련 시 좌석의 높이를 점진적으로 낮추어 제공하는 것이 뇌졸중 환자의 균형회복을 위한 새로운 치료방법으로 임상에서 활용되어 재활의 다양한 방향성을 제시되었음으로 사료된다. 그리고 연구 결과의 일반화를 위해 추후 연구는 많은 대상자에게 훈련의 적용이 필요하며 좌석 높이의 무작위 조성과 같은 다양한 훈련방법에 관한 연구들이 필요할 것이다.

• 대한인간공학회지
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• 제32권1호
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• pp.145-152
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• 2013

Objective: The aim of this study is to develop an ergonomic office chair that has an alarm function for the unbalanced sitting postures. Background: Contrary to expectation, it is reported that office workers sit on their chairs much more in unbalanced postures during daily work. Even though an office worker uses an ergonomically good-designed chair and begins their work in a good sitting posture, his/her posture is likely to shift to the unbalanced bad posture. Therefore, a posture alarm system would be very helpful in keeping office workers' good postures. Method: We developed a prototype chair with four load cells under a seat pan and one load cell beneath a backrest. Through some experiments, we set the criteria for unbalanced bad postures then implemented the criteria into the alarm system of the prototype chair. The chair called e-BASE chair could detect unbalance postures and show alarms for chair users. We also enhanced back support by developing a step-wised folding backrest. Results: The e-BASE chair showed better performance in interface pressure distributions and balanced posture ratio in VDT work. Conclusion: The ergonomic chair with posture alarm function(e-BASE chair) was developed. It showed better performance in seat pressure distribution and in keeping good posture during office work. Application: The posture alarm system and folding backrest can be applied to the new models of office chair.

• 대한인간공학회지
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• 제35권6호
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• pp.493-501
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• 2016

Objective: This study analyzes the effect of angle conditions of rehabilitation equipment used for supporting hemiplegic patients on their rehabilitation training for standing action. The study was performed by adjusting the rear angle of seat inclination through a motion analysis. Background: Owing to a loss of muscle rigidity and degradation of muscle control ability, hemiplegic stroke patients suffer from asymmetrical posture, abnormal body balance, and degraded balance abilities due to poor weight-shifting capacity. The ability to shift and maintain one's weight is extremely essential for mobility, which plays an important role in our daily life. Thus, to improve patients' ability to maintain weight evenly and move normally, they need to undergo orthostatic and ambulatory training. Method: Using a motion analysis system, knee movements on both hemiplegic side and non-hemiplegic side were measured and analyzed in five angles ($0^{\circ}$, $10^{\circ}$, $30^{\circ}$, $50^{\circ}$, $70^{\circ}$) while supported by the sit-to-stand rehabilitation equipment. Results: The knee movements on both sides increased as the angle increased in angle support interval to support a hemiplegic patient's standing up position. In standing up interval, a hemiplegic patient's knee movement deviations on both sides decreased, and the movement differences between hemiplegic and non-hemiplegic legs also decreased as the angle increased. Conclusion: The results of this study showed that the rehabilitation effectiveness increases as the angle increases, leading to a balanced standing posture through the decrease of movement difference between hemiplegic and non-hemiplegic sides and an improved standing up ability through the increase of knee movement on both sides. However, angles higher than $50^{\circ}$ didn't provide a significant effect. Therefore, a support angle under $50^{\circ}$ was proposed in this study. Application: The results of this study are expected to be applicable to the design of sit-to-stand support equipment to improve the effectiveness of the rehabilitation process of hemiplegic patients.

• 한국기계가공학회지
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• 제19권7호
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• pp.41-51
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• 2020

This paper presents the development of a robotic system for rehabilitation of the trunk's ability to maintain postural control under different balance conditions. The system, developed with extensive input from rehabilitation and biomedical engineering experts, consists of a seat mounted on a robotic mechanism capable of moving it with four degrees of freedom (3 rotational and 1 translational). The seat surface has built in instrumentation to gauge the movements of the user's center of pressure (COP) and it can be moved either to track the movements of the COP or according to operator given commands. The system allows two types of leg support. A ground mounted footrest allows participation of legs in postural control while a seat connected footrest constrains the leg movement and limits their involvement in postural control. The design evolution over several prototypes is presented and computer aided structural analysis is used to determine the feasibility of the designed components. The system is pilot tested by a stroke patient and is determined to have potential for use as a trunk rehabilitation tool. Future works involve more detailed studies to evaluate the effects of using this system and to determine its efficacy as a rehabilitation tool.

• Physical Therapy Rehabilitation Science
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• 제5권2호
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• pp.63-69
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• 2016

Objective: To evaluate the effects of sit-to-stand (STS) imagery group training (IGT) on STS movement and balance performance for chronic hemiparetic stroke. Design: Randomized controlled trial. Methods: A total of 30 people with chronic hemiparetic stroke (15 for STS-IGT group and 15 for control) were recruited in this study. The STS-IGT group participated in a videotape-based STS-IGT for 30 minutes a day, five days a week for six weeks, while the control group watched a documentary on television for the same period. The STS-IGT focused on a five-stage protocol. Specifically, external imagery was used during the four phases of the STS movement from the seat of the chair to standing up. All of the participants also participated in a regular rehabilitation program. STS movement and balance performance were assessed using three clinical measures. Results: After training, time to perform the 5-repetition STS test significantly increased in the STS-IGT group (change value, $4.0{\pm}2.0$ sec) compared with the control group (change value, $0.9{\pm}0.7$ sec) (p<0.05). There was a greater improvement in Berg balance scale scores in the STS-IGT group (change value, $0.2{\pm}4.1$ points) compared with the control group (change value, $0.3{\pm}0.9$ points) (p<0.05). There was a greater improvement in Timed Up and Go scores in the STS-IGT group (change value, $2.6{\pm}1.5$ sec) compared with the control group (change value, $0.9{\pm}1.0$ sec) (p<0.05). Conclusions: STS-IGT can be considered as a useful option for restoration of STS movement and balance performance for individuals with chronic hemiparetic stroke who are unable to fully participate in physical activities.

• 디지털콘텐츠학회 논문지
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• 제19권8호
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• pp.1585-1592
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• 2018

휠체어에 대한 균형을 맞추지 못하는 체중 배분으로 인해 기존의 휠체어 시스템은 휠체어가 언덕으로 올라갈 때 뒤집히거나 떨어질 위험에 직면합니다. 이 논문에서는 휠체어를 타는 동안보다 안전하기 위해 통합 된 자이로 센서와 틸트 센서를 사용하여 균형을 제어하는 실시간 새 솔루션을 제안했습니다. 휠체어의 전형적인 특성은 발을 움직이는 데 어려움을 겪는 특수 사용자를위한 것이기 때문에 휠체어 시스템의 균형을 유지하는 것이 중요하고 도움이되었습니다. 우리의 방법에서는 경사 센서의 정보를 이용하여 시트 각을 계산한다. 그러나 휠체어가 움직이는 관성의 법칙으로 인해 틸트 센서의 출력 값에 편차가 있습니다. 따라서 자이로 센서의 출력 인 가속도를 이용하여 각도 값을 최적화해야합니다. Gyro 센서와 Tilt 센서의 조합을 사용하여 이점을 얻었습니다. 또한 전체 시스템의 소비 문제도 해결했습니다. ZigBee 센서 모듈을 사용하여 다양한 실험을 통해 밸런싱 시스템의 전력 소비가 크게 줄어 들었습니다.

• 전기학회논문지
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• 제59권1호
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• pp.138-143
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• 2010

This paper presents the analysis, the fabrication and the test results of a micro passive gas pressure regulator to keep the outlet pressure costant even for a widely-varying inlet pressure. This device is to regulate the outlet pressure according to the applied reference pressure based on the pressure balancing mechanism of the structure including a membrane and a valve. This regulator consists of four layers; a bulk-micromachined silicon substrate, a sandblasted glass substrate, a PDMS valve seat layer and a glass valve layer. The device size is $10\times13\times1.7 mm3$. The device was fabricated by micromachining. The characteristic of the device was analyzed and tested. The characteristic of the fabricated pressure regulator is similar to that obtained from the analysis. The pressure regulator of this paper is feasible for portable systems and miniature drug delivery systems.

• Tribology and Lubricants
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• 제12권3호
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• pp.79-84
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• 1996

One of the greatest dangers in mechanical face seals is the formation of heat checking and thermal stress cracks on the sliding surfaces. These thermal distortions due to non-uniform heating lead to increase the leakage of the sealed fluids and wear, and with balance of the seal can cause the seal faces to part. In this study heat checking and thermal stress cracks are investigated experimentally. These thermal distortions are explained using the thermal models of the conatct geometries between the seal ring and the seal seat. To overcome these thermal problems, the thermohydrodynamic seal is presented. The newly developed mechanical seal may substantially reduce the friction torque, frictional heating which causes heat checking and thermal stress cracks, and wear.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.415-420
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• 2007

The objective of this study analyzes the influence of shimmy & shake phenomena due to tire design parameters which are RFV(radial force variation), DB(dynamic balance), RRO(radial run out) and air pressure. These parameters are inspection items for Q.C. after tires are manufactured. In order to analyze these parameters on this study, vehicle driving tests were achieved. The test modes are two type which are constant speed and coast-down driving. On this tests the dynamic characteristics of shimmy & shake are measured by the 3-axises accelerometers at the various positions that are knuckle(left & right), rack pinion, seat and steering wheel. In according to analyzed results, the longitudinal vibration of knuckle parts affects the lateral vibration of rack pinion and this vibration affects the lateral vibration of steering wheel that is the shimmy phenomena. Also the over and under DB by comparison with normal DB and the increment of RRO affect the occurrence of shimmy & shake phenomena.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2016년도 춘계학술대회
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• pp.537-538
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• 2016

최근 현대인들은 많은 업무와 학업으로 인한 좌식 생활의 빈도가 증가하면서 잘못된 자세와 잘못된 습관으로 인해 습관성 척추-골반 질병이 많이 발생하고 있다. 따라서 이를 방지하고 지속적인 바른 자세를 유도하기 위해서는 착석 정보를 기반으로 자세정보를 판단하여 유도할 수 있는 시스템이 요구된다. 본 논문에서는 자세안정도를 평가하기 위하여 추적 계측할 수 있는 장비의 개발과 잘못된 자세가 검출될 시에는 사용자에게 알려주어 실시간 모니터링을 통해 스스로 자세를 교정하는데 도움을 주는 어플리케이션의 구현에 대해 기술하였다.