• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2002.07a
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• pp.327-332
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• 2002

식물조직배양용 바이오리액터내 배양액의 pH, DO 농도를 on-line으로 계측하고 제어하기 위한 시스템을 개발하여 시스템의 성능시험과 경시간격별 배양액의 농도변화를 계측하였으며, 주요 연구결과는 다음과 같다. 가. 복수의 바이오리액터내 배양액의 pH, DO 농도를 전극을 이용하여 on-line으로 계측하며, 농도의 계측값과 목표값을 비교하여 피드백으로 제어할 수 있는 시스템을 개발하였다. 나. 배양액의 농도변화를 계측한 결과 pH는 배양초기 5.0에서 배양이 경과됨에 따라 서서히 떨어져 2개월 후에는 3.8까지 떨어지는 것으로 나타났다. 다. 배양액의 성분중 배양초기에는 암모니아태 질소의 흡수가 질산태 질소보다 많이 이루어져 구근으로부터 H+이온을 유출시킴으로 pH의 값이 떨어지는 것으로 나타났다. 라 오염이 발생한 리액터내의 배양액 성분은 pH의 값이 3이하로 떨어졌으며, 이로부터 배양액의 오염경보를 할 수 있는 것으로 나타났다.

• Proceedings of the Korean Information Science Society Conference
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• 2001.10c
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• pp.847-849
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• 2001

방대한 양의 실시간 연산을 요구하는 영상 신호처리, 소나, 레이다와 같은 시스템에서는 성능을 최대화하기 위해 병렬 신호처리 시스템의 사용이 불가피하다. 본 논문은 2개의 DSP칩(TMS320C6701)을 사용하여 설계 및 구현한 병렬 신호처리보드의 구성과 이를 구동시키기 위한 소프트웨어 구성체계를 제시한다.

• KIEAE Journal
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• v.4 no.4
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• pp.45-52
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• 2004

Simulation of daylighting by computer program is a method to avoid unnecessary efforts in manufacture of its testing models, to reduce its measuring tolerances and be able to provide variations of various weather conditions as well. Many simulation programs on daylighting have been released freely or commercialized for selling, however, a demonstration of their availability and validity as a tool for evaluating daylighting performance is required since each one has its own characteristics. The objectives of this study lie in suggesting an application method of evaluation tools and demonstration of limits and characteristics so as to more easily determine the daylightingperformance in the very initial stages of planning for an arbitrary office space in which windows with daylight access are built. We produced scale model of the general light inducing type side lighting with lightshelfand ceiling, and the luminance (at 78 measuring points) and illuminance (at 84 measuring points) were measured in a clear sky. And a comparison of the measured values and the calculated values from a computer simulation using the Lightscape program was performed.

• Proceedings of the KIEE Conference
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• 2001.04a
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• pp.222-226
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• 2001

본 논문에서는 단상 H-bridge 구조의 VSC (Voltage Source Converter)를 이용하여 계통전원을 사용하는 부하의 고조파 전류 보상기능과 전원 Back-up 기능을 갖는 부하전력보상기를 보여준다. 이 두 제어 기능은 전원전압의 유무에 따라 APF의 컨버터 동작과 UPS의 인버터로 동작하게 함으로써 기존 UPS에 부하 전류의 고조파 보상이라는 부가적인 이득을 갖는 이중전력보상기(Dual Function Power Compensator)라 할 수 있다. 컨버터 제어는 Battery 충전 동작과 APF 동작을 동시에 수행하며, 인버터 제어는 정전시 부하에 전원을 공급하는 UPS로서의 동작을 수행하게 된다. 두가지 동작이 성공적으로 수행되기 위해서는 1. 전원전압의 신속한 검출과 판단, 2. 컨버터의 Battery 충전, 3. APF동작을 위한 부하전류의 고조파 전류계산, 4. 전원전압의 동기추종 등이 각각의 동작모드별로 순조롭게 연계동작 되어 야 한다. 본 논문에서는 DFPC의 발생배경과 제안된 DFPC 제어모드의 구분을 결정하는 전원전압의 검출방법에 대하여 소개한다. 그리고 제안된 DFPC의 실제 시스템을 제작하여 각각의 동작상황과 성능을 시험하여 그 결과를 보여준다.

• 유체기계공업학회:학술대회논문집
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• 2004.12a
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• pp.552-557
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• 2004

Effects of a booster inducer on the suction performance of turbopumps are investigated in this paper. To see the effect of the booster inducer, suction performance tests are conducted with and without the booster inducer for three turbopumps. It is shown that the booster inducer can enhance the suction performance of turbopumps when the tip clearance of the main inducers are relatively large. Numerical analysis are also carried out to see the effects of the booster inducer on the performance of the main inducer. The booster inducer is shown to increase the static pressure at the inlet of the main inducer and prevent growing of inlet back flows which are believed to have deleterious effects on the suction performance of the inducer.

• 유체기계공업학회:학술대회논문집
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• 2004.12a
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• pp.558-563
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• 2004

Experiments were performed to see the effect of radial tip clearance on a turbopump inducer, which has two blades with inlet tip blade angle of 7.8 degree and tip solidity of 2.7. Hydraulic and cavitation tests were done for three cases of tip clearance ratio, that is, 0.026, 0.053, and 0.079. With increase in the tip clearance, inducer head and pressure on the inducer tip decreased. Attached cavitation and cavitation surge were found in the cavitation tests. In the attached cavitation one cell rotated at the same rotational speed as that of the inducer. Cavitation performance deteriorated with increase in the tip clearance. The level of casing vibration increased in the cavitation condition and the level was very high when the attached cavitation appeared.

• Journal of the Korea Safety Management & Science
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• v.14 no.2
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• pp.185-192
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• 2012

It has been a huge amount of capacity of 10GB data base in a decade ago so far. Nowadays, however, 10TB is the common data base and even bigger capacities are available. So, new generation of Very Large Data Base (VLDB) has begun. Moving in to the new generation of VLDB has been caused major problems like backing up, restoring, and managing especially performance. It is very hard to export necessary data rapidly now due to the huge amount of data base. In the past, such kind of problems was out of the questions because of less data. As time goes on, however, optimization of performance became a big issue when the VLDB is common. Therefore, new professional technics are urgently required to maintain and optimize the data base that has become a VLDB or one that is in the progress of becoming one.

• Proceedings of the Safety Management and Science Conference
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• 2010.04a
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• pp.167-172
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• 2010

EPCIS(EPC Information Service)시스템은 EPC기반의 정보교환을 목표로 EPC global Network 상에서 RFID 태그에 기록된 화물의 EPC데이터, 인식시점, 인식장소 등의 정보를 제공하는 EPCglobal Architecture Framework의 구성요소 중 핵심부분이라고 할 수 있다. 본 논문에서는 EPCIS 시스템의 구성요소 중 동시에 수많은 RFID 단말기로부터 입력되는 대용량의 EPCIS Event 데이터를 지속적으로 저장하고 관리하는 EPCIS Repository를 효율적으로 관리하기 위하여 고성능이 필요한 데이터와 대용량이 필요한 데이터를 모두 처리할 수 있는 Hybrid DBMS를 적용하여 EPCIS Repository를 효율적으로 관리할 수 있는 방안을 제시하고자 한다.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.1225-1230
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• 2008

Recently the building material have been developed with the concept of controlling the indoor environment as well as the concept of emitting contaminants less. So, a lot of products with humidity control characteristics put it on the market. However, objective evaluation to these products doesn't work out. Thus consumers cannot obtain accurate information to these products. Therefore, we selected inorganic paint in the functionality materials and evaluated its humidity control characteristic in this research. We divided by four stages and evaluated this inorganic paint. The 1st and 2nd third experiments were executed on a natural condition and the fourth experiment was executed with humidity had been raised by using the humidifier.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.714-719
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• 2008

In a domestic construction field, after floor is constructed, protector for construction surface is set up to prevent the surface of the floor being scratched and polluted. However, the problem is that contaminants discharged with the removal of the protector for construction surface exert a bad influence for the indoor air quality. In the research, it tested to the contaminant reduction performance of the adsorption protector for construction surface using powder of charcoal by the alternative proposal of such protectors for construction surface