• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 1996년도 International Conference on Agricultural Machinery Engineering Proceedings
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• pp.906-917
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• 1996

This study was conducted to find possible application areas of the by-products generated from the incineration of rice husk. To this end, a pilot-scale rice husk incinerator system was constructed and its performed test was carried. Major findings are summarized as follows. 1. The rice husk incinerator system developed in this study performed satisfactory in terms of thermal efficiencies. At the optimum operating conditions, thermal conversion efficiency and heat exchanger efficiency was 97% ad 60%, respectively, while overall thermal efficiency of the system was 58%. Under all conditions tested, temperatures in the combustion chamber were quite uniform and crystallization of SiO$_2$ in the ash was negligible. 2. NOx and SOx content in the flue gas was well below the legal limit but the CO concentration was around the legal limit. 3. Thermal energy from combustion was successfully recovered by a heat exchanger to provide hot water, ash was found a good supplementary cementing m terial, and the flue gas also was an acceptable $CO_2$ supplier to greenhouses.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 1996년도 International Conference on Agricultural Machinery Engineering Proceedings
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• pp.834-841
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• 1996

Egg production in Korea is becoming automated with a large scale farm. Although many operations in egg production have been and cracks are regraded as a critical problem. A computer vision system was built to generate images of a single , stationary egg. This system includes a CCD camera, a frame grabber board, a personal computer (IBM PC AT 486) and an incandescent back lighting system. Image processing algorithms were developed to inspect egg shell and to sort eggs. Those values of both gray level and area of dark spots in the egg image were used as criteria to detect holes in egg and those values of both area and roundness of dark spots in the egg and those values of both area and roundness of dark spots in the egg image were used to detect cracks in egg. Fro a sample of 300 eggs. this system was able to correctly analyze an egg for the presence of a defect 97.5% of the time. The weights of eggs were found to be linear to both the projected area and the perimeter of eggs v ewed from above. Those two values were used as criteria to sort eggs. Accuracy in grading was found to be 96.7% as compared with results from weight by electronic scale.

• Journal of Biosystems Engineering
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• 제27권4호
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• pp.273-282
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• 2002

This study was intended to measure and analyze hand-transmitted vibrations from cultivator in idle and operation modes for three different types of field works. Based on this analysis a time for the white finger syndrome to appear on 10% of the operators was estimated assuming that their daily exposure is 3 hours. The 4 methods to reduce the hand vibration were also proposed and compared with each other. The results of the study were summarized as follows : The highest vibration level was recorded during trenching operation, resulting in a total average vibration of 11.5 m/s$^2$. Followings were 7.6 m/s$^2$ during rotary tillage and 7.0 m/s$^2$ for weeding. When exposed to these levels of vibrations three hours a day, the white finger syndrome is likely to appear in 4 years for trenching, 6.2 years for rotary tillage and 6.8 years for weeding operations. Isolation of hand vibration performed by a rubber pad, anti-vibration gloves, a handle anti-vibration device and engine mounts were respectively 15.7%, 16.5%. 26.1% and 27.0%, resulting in most effective methods of the handle anti-vibration device and engine mounts. A better performance of about 33.9% was achieved when both the handle anti-vibration device and engine mounts were used.

• Journal of Biosystems Engineering
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• 제4권1호
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• pp.24-34
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• 1979

현재 실용테라스 (Terrace) 축조비용의 추정은 단위 테라스장이나 이동토양의 단가에 근거하고 있다. 그런, 근래 l국의 옥수수 지대 (corn belt)에서 널리 이용되고 있는 평행형 테라스의 경우 각 지점마다 성토 및 절토양이 다르기 때문에 이들 방법은 적합하지 않다. 이들 테라스의 경우 테라스장을 따라 토양의 이동이 불가피하므로 차륜형 자적식 스크레이퍼(scraper)가 테라스 축조에 널리 사용되고 있다. 본연구의 목적은 테라스 축조기계의 운행거리에 근거하여 테라스 축조시의 토공비용을 추정하기 위한 새로운 방법을 개발하는데 있었다. 테라스 축조시 토공작업은 전적으로 스크레이퍼에 의해서 , 그리고 테라스 경호장의 마무리 작업은 모트그레이터 (motor grader )에 의하여 수행되는 것을 가정하였다. 이들 기계의 세부적인 수행동작은 테라스 각지점에서의 절토와 성토량 및 이들 토양의 처리를 디지털 컴퓨터(digital computer)를 이용하므로서 계산할 수 있었다. 또한 테라스 축조에 소요되는 토양은 전적으로 테라스 수로부문에서 절취하는 것으로 가정하였다. (즉, 테라스 전장의 총절토양 과 총성토양은 같음) 연구결과 다음과 같은 결론을 얻었다. 1. 성토 및 절토양이 균형된 테라스에 있어서는 스크레이퍼의 운행거리에 근거하여 토공비용을 추정할 수 있는 방법의 개발이 가능하다. 2. 스크레이퍼의 수행구간, 회수 및 토공비용을 결정하기 위해서는 컴퓨터 방법을 이용하는 것이 필요하다. 3. 새로운 컴퓨터 모델은 예시의 테라스에 적용한 결과 테라스 토공비용을 추정하는 데 적합함을 보여주었다. 4. 이 방법은 테라스 축조에 있어서 효율적인 스크레이퍼의 적용에 지침이 될 수 있다.

• 한국재료학회지
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• 제12권1호
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• pp.27-35
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• 2002

In laser materials processing, localized heating, melting and evaporation caused by focused laser radiation forms a vapor on the material surface. The plume is generally an unstable entity, fluctuating according to its own dynamics. The beam is refracted and absorbed as it traverses the plume, thus modifying its power density on the surface of the condensed phases. This modifies material evaporation and optical properties of the plume. A laser-produced plasma plume simulation is completed using axisymmetric, high-temperature gas dynamic model including the laser radiation power absorption, refraction, and reflection. The physical properties and velocity profiles are verified using the published experimental and numerical results. The simulation results provide the effect of plasma plume fluctuations on the laser power density and quantitative beam radius changes on the material surface. It is proved that beam absorption, reflection and defocusing effects through the plume are essential to obtain appropriate mathematical simulation results. It is also found that absorption of the beam in the plume has much less direct effect on the beam power density at the material surface than defocusing does and helium gas is more efficient in reducing the beam refraction and absorption effect compared to argon gas for common laser materials processing.

• International Journal of Fluid Machinery and Systems
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• 제9권1호
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• pp.17-27
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• 2016

Researches on the mechanism of surging and the surge behaviors in the systems of pumps, or fans or compressors, and the effects of flow-paths had been initiated and had made a great progress in Japan in the decades from the nineteen-forties to the nineteen-sixties. In 1947, the essential cause of the surges, i.e., self-excited oscillation nature of the flow-system, was discovered analytically by Professor Sumiji Fujii of Tokyo University, and most of the characteristic behaviors of the phenomena had been explained clearly. Successive studies by many other Japanese researchers continued to prove experimentally the mechanism, to extend the analytical studies, and to attempt preventing surge occurrence, etc. in the following two decades. The historical information on the early surge studies could be helpful to some concerned people. At the same time, the basic and plain ways of discussions and reasoning about the phenomena in the pioneering researches could give us much to be learned even in the present time of high-power computing systems. Regrettably, many of the original research works have been published only in Japanese. The present review introduces very briefly the situations in memories of the pioneering researchers and engineers.

• 한국지열·수열에너지학회논문집
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• 제10권2호
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• pp.1-6
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• 2014

As Korea's economy is entering a period of gradual growth, rate of growth on the construction market is becoming slow like that in developed countries. Remodeling construction market will be gradually expanded due to change in the social environment and diversification of individual demand. This study aims to promote the status of building equipment field with corresponding strategies based on the current situation that the importance of building equipment field is emphasized. Although it is desirable that building equipment construction companies lead remodeling construction, the building equipment part of general construction companies take the important role may be a advisable way, because the technology of building equipment construction companies is a little insufficient. Though building equipment field has become more important, the number of credits and professor of the field is still small than other fields of architectural engineering. More practical curriculums are necessary to meet the expectation of companies. Mechanical part of building equipment construction does not have independent law otherwise the other parts of building equipment construction. Establishing the independent law is urgent to promote the remodeling construction technology.

• Journal of Biosystems Engineering
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• 제25권4호
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• pp.273-278
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• 2000

The hybrid heat pump system of the air to air and / or air to water was composed and its COP was analyzed with the ambient temperature on the opened and closed loop system respectively. The results be indicated by the equation(7) that the COP(Coefficient of Performance) of air-source(air to air and / or air-water) heat pump is effected with the ambient air temperature and AVACTHE.(Automatic Variable Area Capillary Type Heat Exchanger) 2. The COP of air-to-water heat pump without AVACTHE decreased in accordance with the ambient temperature decrease, however in case of the heat pump with AVACTHE the COP was maintained at 2.8∼3.0 level when the ambient temperature decrease from -$5^{\circ}C$ to $-11^{\circ}C$. 3. The COP of the air-to-water heat pump operated on the open loop was higher 40∼58% than that of the heat pump operated on the close loop. 4. The lower ambient temperature air effect on the COP of the air-to-air heat pump operated on the semi closed loop could be controlled using the AVACTHE, and at the high ambient air temperature the COP increased using the Bypass circuit.

• 한국정보전자통신기술학회논문지
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• 제8권3호
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• pp.239-242
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• 2015

시각장애인들은 외출을 하기 위해 보행 보조기기를 사용하고 있다. 또한, 최근에는 보행 보조기기뿐만 아니라 음성인식 명령기능을 탑재한 스마트폰도 이용하고 있다. 이러한 추세에 따라, 본 논문에서는 시각장애인 보행 보조를 위한 스마트 폰 케이스를 설계하고 구현하였다. 조도 센서와 스마트폰 카메라 플래시를 이용하여 어두운 장소에서 자신의 위치를 알려주는 자기 위치 알림 시스템과 초음파 센서를 이용하여 장애물을 감지하고 시각장애인들에게 음성으로 경고를 해주는 음성 경고 시스템을 제공한다. 이를 이용하면 시각장애인은 어두운 곳에서 자신의 위치를 알리고, 전방의 장애물을 피해갈 수 있어서 보다 안전하게 보행하여 사고를 방지할 수 있다.

• 한국정보통신학회논문지
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• 제12권6호
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• pp.1064-1069
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• 2008

본 논문은 인터프레임 확률분포에 의한 비디오 감시 시스템 설계 구현에 관한 것이다. 시스템은 비디오 분석 알고리즘과 표준 JPEG 압축 알고리즘을 처리하기 위해 고성능 DSP 프로세서 기반으로 구현된다. 비디오 분석은 가중치, 평균, 분산의 3변량정규분포에 의한 인터프레임 확률분포 분석을 이용하여 특정 영역에 물체를 검출하는 알고리즘을 사용한다. 실험 결과, 시스템 처리시간이 D1$(720{\times}480)$ 영상 프레임 당 85ms 소요되었고 초당 12프레임 정도 처리한다. 규칙에 따른 특정영역 물체감시는 움직임 빠르지 않는 물체에 대해 100% 검출되었다.