• 한국정보전자통신기술학회논문지
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• 제13권1호
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• pp.1-7
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• 2020

음향 시스템의 지향성 제어기술은 음향의 품질 향상을 위한 핵심 기술이다. 음향 시스템에서 점 음원이 아닌 선음원을 제공하면 원거리에서 감쇠 간섭의 영향을 줄일 수 있기 때문에, 고품질의 음향을 제공할 수 있다. 특히, 라인 어레이(line-array) 스피커 시스템을 이용하면 원거리까지 균일한 고품질의 음향을 제공할 수 있다. 그러나, 고음은 파장이 짧기 때문에 라인 어레이 시스템의 스피커간의 거리가 짧아야 하지만 물리적인 한계가 있다. 본 논문에서 이러한 문제점을 해결하기 위해 웨이브 가이드를 설계하고 스피커 유닛에 장착하였다. 개발된 스피커의 성능 확인을 위해 다양한 음향특성을 측정하고 테스트 하였다. 그 결과 개발된 스피커를 이용하여 라인 어레이 음향 시스템을 구성하면 고음 영역을 포함한 모든 영역에서 선 음원을 제공할 수 있기 때문에 단일 확장 음원과 같은 효과를 얻을 수 있고, 원거리까지 고품질의 음향을 제공할 수 있음을 확인하였다.

• 한국가스학회지
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• 제14권4호
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• pp.56-62
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• 2010

본 논문은 LPG 엔진의 전자제어센서에 대한 고장사례를 분석하고 고찰한 연구이다. LP가스의 연료 분사량을 컨트롤하는 크랭크 각도센서의 기능이상은 불규칙하고 불균일한 파형형태로 나타나고 있다. 크랭크 각도센서의 노이즈에 관련된 파형은 톱니형의 불규칙한 피크형상으로 나타났고, 2.46V 정도의 노이즈 레벨이 간헐적으로 발생하고 있다. 1번 TDC센서의 내부불량으로 인해 발생한 고장사례는 엔진의 출력을 떨어뜨리고 시동을 간헐적으로 꺼지게 하는 문제점을 초래한다. 산소센서의 성능이상은 센서의 배선에서 연결이 단절되었기 때문에 발생한 것으로 차량의 울컥거리는 현상과 엔진의 부조화 현상이 나타나고 있다. 에어 크리너를 이종품으로 사용한 경우는 신기가 정상적으로 공급되지 못했기 때문에 차량의 가속불량과 엔진의 부조화 현상이 발생하는 원인으로 작용하고 있었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.324-327
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• 2005

An electrophoretic display using $TiO_2$ particles is the most promising candidate because it offers various advantages such as ink-on-paper appearance, good contrast ratio, wide viewing angle, image stability in the off-state and extremely low power consumption. The core technology of electrophoretic display is the dispersion controlling of $TiO_2$ nano particles in nonaqueous solution. To prepare an ink for electronic paper using electrophoretic properties of $TiO_2$ nano particles, cyclohexane with low dielectric constant and transparency, polyethylene for producing polymer coating layer which reduces apparent gravity of $TiO_2$, and $TiO_2$ powders were mixed together by planetary-mill. The zeta-potential value of $TiO_2$ particles in cyclohexane was measured about -40mV, but was measured over -110mV by dispersant attached to polyethylene-coated $TiO_2$ surface. Prepared electronic ink was filled in cross patterned micro-wall with $200{\mu}m$ in width and $40{\mu}m$ in height on ITO glass designed by photolithography. The response time of electronic paper evaluated by mobility of $TiO_2$ particle between micro-walls was measured 0.067sec, but the drift velocity from reflectance wave form during reverse from of electronic ink was measured 0.07cm/sec.

• 한국식품과학회지
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• 제38권1호
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• pp.16-21
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• 2006

본 연구는 야자유를 190, $220^{\circ}C$에서 24시간 가열한 후 6개의 MOS로 구성된 전자코로 산패정도를 판별하였다. 주성분분석 결과 제1주성분 값이 열처리 시간에 따라 +0.952에서 0.325로 감소하였다. 가열 온도를 높임에 따라 야자유의 산패정도도 증가하였다. 또 다른 방법에 하나로 GC를 바탕으로 한 SAW센서가 부착된 전자코를 사용한 결과 후각이미지가 뚜렷하게 차이가 나는 것을 보여주었다. 160, $220^{\circ}C$에서 가열한 야자유로부터 휘발 성분에 대한 GC peak의 수와 넓이가 가열온도와 가열 처리 시간에 따라 증가함을 보여주었다. 이러한 방법은 신속하면서도 곧바로 알기 쉽게 데이터를 이미지화함으로써 가열 처리된 야자유의 휘발성분을 전자코로 신속하고 간편하게 분석하여 가열 처리 정도가 예측 가능하였다.

• 한국산학기술학회논문지
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• 제15권5호
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• pp.2655-2661
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• 2014

본 연구는 치유예술로서의 춤이 여성노인의 뇌기능에 어떤 영향을 미치는 지, 2channel system EEG를 통해 검증하였다. 연구 대상은 K시 소재 65세이상 여성노인 60명, 연구기간은 2013년 3월에서 2013년 7월까지, 주 1회, 회기 당 60분씩, 총 16주 동안 프로그램을 실시하였다. 참여대상 30명은 실험집단, 30명은 통제집단으로 구성하여 프로그램 실시전후에 뇌파를 측정하였다. 연구 결과는, 실험집단에서 기초율동지수 좌뇌 사후(79.11/89.56, p<.015), 주파수우뇌 사후 평균값(8.33/9.37, p<.003), 진폭좌뇌 사후 평균값(39.87/47.19, p<.006), 진폭우뇌 사후(40.09/49.87, p<.000)의 상승을 보였다. 따라서 치유예술로서의 춤이 여성노인의 기초율동지수, 주파수와 진폭을 상승시켜 뇌기능 향상 프로그램으로서의 효용과 가치를 검증하였다.

• 한국ITS학회 논문지
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• 제14권1호
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• pp.1-12
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• 2015

매설형 검지기는 검지 성능이 타 검지기에 비해 우수하지만, 설치 및 관리비용이 클 뿐 아니라 도로의 재포장이나 도로파손으로 인해 수명이 짧다는 단점이 있다. 이에 반해 기존 지주에 부착하여 사용하는 검지시스템인 비매설형검지기는 도로 노면을 손상시키지 않기 때문에 설치가 쉽고, 유지관리비용이 적다는 장점이 있다. 비매설식 검지기는 이러한 장점에도 불구하고, 검지 성능이 낮아 아직까지 신호제어용으로 사용하지 못하는 실정이다. 본 연구에서는 비매설형검지기 중에 정확도가 가장 높은 FMCW 방식의 레이더에 대해 성능평가를 수행하고, 신호제어용 검지용도별로 현장적용 유/무 결과를 제시하였다.

• 수산해양기술연구
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• 제54권4호
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• pp.343-352
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• 2018

In this study, a motion control problem for the vessels towed by tugboats or towing ships on the sea is considered. The towed vessel looks like the barge ship, which is used for many purposes. In these vessels, basically, the power propulsion system is not installed but just towed by a towing vessel such as tugboats with ropes and wires. It means that the motions of towed vessel are basically dependent on the tracking route of towing boat. Therefore, in some cases, undesirable and unpredictable motions may be made by environmental factors such as wave, wind attack and so on. As a result, a collision accident with others may occur during maneuvering situation. Based on these facts, the authors try to encourage the steering performance of the towed vessel by using controllable rudders without any propulsion system. In this study, especially, a controllable vessel with three rudders is considered, and a mathematical model is induced for the future study. The model is described as surge, sway motion and inertia moment by following the general representation method for the surface ship.

• 한국운동역학회지
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• 제29권2호
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• pp.105-112
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• 2019

Objective: The main purpose of this study was to investigate the effects of wearing an ankle weight belt while performing gait in water by focusing on the effect of using ankle weights have on the gait kinematics and the muscle activities for developing optimum training strategies. Method: A total of 10 healthy male university students were recruited for the study. Each participant was instructed to perform 3 gait conditions; normal walking over ground, walking in water chest height, and walking in water chest height while using ankle weights. All walking conditions were set at control speed of $4km/h{\pm}0.05km/h$. The depth of the swimming pool was at 1.3 m, approximately chest height. The motion capture data was recorded using 6 digital cameras and the EMG was recorded using waterproof Mini Wave. From the motion capture data, the following variables were calculated for analysis; double and single support phase (s), swing phase (s), step length (%height), step rate (m/s), ankle, knee, and hip joint angles ($^{\circ}$). From the electromyography the %RVC of the lower limb muscles medial gastrocnemius, rectus femoris, erector spinae, semitendinosus, tibialis anterior, vastus lateralis oblique was calculated. Results: The results show significant differences between the gait time, and step length between the right and left leg. Additionally, the joint angular velocities and gait velocity were significantly affected by the water resistance. As expected, the use of the ankle weights increased all of the lower leg maximum muscle activities except for the lower back muscle. Conclusion: In conclusion, the ankle weights can be shown to stimulate more muscle activity during walking in chest height water and therefore, may be useful for rehabilitation purposes.

• Advances in Computational Design
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• 제4권1호
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• pp.53-72
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• 2019

Safety measures for tower cranes are extremely important among the seismic countermeasures at high-rise building construction sites. In particular, the collapse of a tower crane from a high position is a very serious catastrophe. An example of such an accident due to an earthquake is the case of the Taipei 101 Building (the author was the project director), which occurred on March 31, 2002. Failure of the bolted joints of the tower-crane mast was the direct cause of the collapse. Therefore, it is necessary to design for this eventuality and to take the necessary measures on construction sites. This can only be done by understanding the precise dynamic behavior of mast joints during an earthquake. Consequently, we created a new hybrid-element model (using beam, shell, and solid elements) that not only expressed the detailed behavior of the site joints of a tower-crane mast during an earthquake but also suppressed any increase in the total calculation time and revealed its behavior through computer simulations. Using the proposed structural model and simulation method, effective information for designing safe joints during earthquakes can be provided by considering workability (control of the bolt pretension axial force and other factors) and less construction cost. Notably, this analysis showed that the joint behavior of the initial pretension axial force of a bolt is considerably reduced after the axial force of the bolt exceeds the yield strength. A maximum decrease of 50% in the initial pretension axial force under the El Centro N-S Wave ($v_{max}=100cm/s$) was observed. Furthermore, this method can be applied to analyze the seismic responses of general temporary structures in construction sites.

• 패션비즈니스
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• 제23권2호
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• pp.156-169
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• 2019

The objective of this study was to develop lightweight, stretchable, tight-fit smart sportswear using the conductive yarns into the garment and demonstrating its usefulness. Sportswears with the ability to control LEDs with respect to lighting of the surrounding were developed by applying embroidery with conductive yarns to 2 types of men's T-shirts and 2 types of women's leggings pants for outdoor activities and exercise purposes. LEDs were applied to the front and back of men's T-shirts and to the rear of the waist of women's leggings. Men's T-shirts were printed where the LEDs were to be applied, and inside, they were embroidered with conductive threads on the hot-melt fabric to be attached, and then connected with LED. Women's pants were embroidered on the elastic band, in the form of a sine wave that gives it ability to stretch, and finally the elastic band was hidden inside the waistband. The operation of the light sensor in the dark provided the ability to protect joggers from night drivers or cyclists. LEDs were activated when the wearer turns on the fashionable device on his/her shoulder by pressing it. It was able to reduce the risk of accidents by giving recognizability to vehicles, bicycles, and athletes approaching or passing by at night, and securing safe distance from vehicles, etc. Internal embroidery technology had the same flexible and lightweight functions as ordinary clothing products, making it possible to apply to tight-fit smart T-shirts or leggings pants designs.