• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.745-748
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• 2002

Many malfunctions take place in container crane spreader due to impact. So we designed a 2DOF hydraulic impact absorbing system and studied the change of impulse with respect to the variation of falling height and weight. The falling height becomes higher than 1m and the falling weight goes up heavier than 100kg, the impact absorbing rate was lower. When spreader is bumped against container and impulse force concentrates on one point, impact absorbing equipment would not be operated properly and make some trouble.

• Journal of Korea Society of Industrial Information Systems
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• v.4 no.3
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• pp.28-36
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• 1999

Environmental problems arise from the rapidly developing personal computers and are gradually becoming a significant part of problems. Computer industry are usually viewed as relatively clean. However, discarded personal computer and related equipment which are piling up at warehouse, or going to landfills has on the negative effects of hazardous substance on health and the ecosystem are growing problems which did not trouble society a few years ago. This paper will estimate the quantity of the obsolete personal computer in 1999 and suggest the alternatives of its disposition.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.12
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• pp.4685-4690
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• 2010

New E-EGR valve design to suppress a carbon deposit causing a trouble in the valve by improving gas flow velocity is proposed. With CFD simulations of various shapes of valve disk and rod, the velocities and quantities of flowing fluid are observed. The proposed unique design of having round grooves on the disk head shows the improved performance of flow velocity about 10 % without sacrificing the flow quantity.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.252-253
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• 2011

Many errors are broken out when hydro power plants are operating connected to electric power system. To minimize ripple effects of accidents, a hydro power plant is separated by a circuit breaker consisting of each protection equipments. In this paper, I will analyze a cause of abnormal events of emergency stop and therefore I take measures and suggest solutions for similar cases.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.55-59
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• 2004

Recently, life cycle and lead-time of products have been shortened with the demand of customers. Therefore, it is important to reduce time and cost at the step of manufacturing trial molds. In order to realize three dimensional shape on CAD, the machining process has been widely used because it offers practical advantages such as precision and versatility. However, traditional machining process spends a lot of time in cutting product and the remained material causes trouble such as inconvenience for clean. In this work, a new machining process using the hot tool has been proposed to overcome those limitations. In the process, the hot tool moves the predetermined path and the heat of the tool decomposes the remained material. In order to set up the process, the hot tool to satisfy requirements is designed and the material thermal properties are obtained using the DSC and TGA machine. The relationships between process parameters and thermal radius of the tool are obtained through experiment.

• Journal of the Korean Society of Safety
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• v.7 no.4
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• pp.33-43
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• 1992

A methodology to develop an expert system for chemical plant fault diagnosis based on functional-structure of chemical plant is proposed. A methodology to generalize and utilize the heuristic know-edge of plant operators is also developed. A plant can be seen as a Hierarchical set of subsystems. Each subsystem is called a SCOPE. The state of the plant and the behavior of each subsystem is managed by the SCOPES. An expert system based on this functional structure and knowledge base has been developed and ar plied to the subprocess of etylene plant to evaluate the effectiveness of the methodology.

• Korean Journal of Microbiology
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• v.1 no.1
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• pp.26-29
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• 1963

1. Cooked soybean was fermented for about a week by Bacillus megatherium 88-3, D-28 and D-28a; and compared with the cooked soybean which was not fermented, this fermented soybean showed much increase in vitamin $B_{12}$ and $B_2$, while vitamin $B_1$ decreased. 2. In the process of fermenting the cooked soybean, Bacillus megatherium, 88-3 is the bacteria which produces brown pigment; and Bacillus megatherium D-28 and D-28a is the bacteria which produces yellow pigment. 3. In weight, fermented soybean-fed rat showed more increase than the unfermented soybean-fed rat. But the growth of the rat fed with Bacillus megatherium 88-3 fermented soybean was not good. Probably, this phenomenon came from the trouble in rat's metabolism by brown pigment. 4. In food efficiency, Bacillus megatherium D-28a is 4.3% lower than Bacillus megatherium B-938, but it is 17.l% higher than the unfermented cooked soybean. Bacillus megatherium 88-3, which is 47.1% lower in food efficiency than the unfermented cooked soybean, has been found "not good" in the growth of rat.th of rat.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.1059-1064
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• 2001

This study is about accurate steel column position method in the Top down method's delicate part. When the concrete is placing, it is required that complementary measures to the transformation due to concrete pressure, column buckling, the trouble due to bar net inserting and so on. To solve the problem of exist method, the concrete is placed at the bottom of excavated hole in advance. then, the steel column is inserted into the excavated hole. With a new method try, the problem due to placing pressure and others is could be prevented. In this study, the concrete is examined with test-slump, slump flow, and compressive strength to do quantitative analysis of concrete. The factors of the experiment is plasticizer, retarder addition rate, fly ash substitution rate to cement. Considering of the new method try, the retarder added concrete properties-fluidity, viscosity, strength-is investigated as time lapsing.

• Journal of Environmental Health Sciences
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• v.27 no.3
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• pp.43-48
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• 2001

Terephthalic acid and ethylene glycol resulting form the weight-reduction process of polyester make trouble in the operation of activated sludge process. Also, polyester weight loss wastewater shows high pH, high organic strength and wide variation of organic loading. Therefore, this study was conducted in order to improve treatment efficiency by activated sludge process with Pseudomonas sp degrading components of polyester weight loss wastewater. The CO $D_{Mn}$ and BO $S_{5}$ of the waste wastewater were 560~3,000 mg/$\ell$ and 8000~3,000 mg/$\ell$, respectively. pH was 11.8~12.3. COD removal efficiency by activated sludge-coagulation process with Pseudomonas sp was 94.1~95.8% for 35 hr of hydraulic retention time. Total organic carbon removal efficiency was 97.1%. Ethylene glycol and terephthalic acid in the wastewater were completely degraded during 32 hr of hydraulic retention time.e.

• The Journal of the Korea institute of electronic communication sciences
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• v.2 no.1
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• pp.34-39
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• 2007

Submarine cable is the leading means of international communication across oceans. However, when such important submarine cable is damaged, that causes not only huge amount for the repair but also losing the nation's reliability internationally, and has brought about much difficulty and loss due to the interruption of communication. So, in order to deduce methods for the stability of submarine cables, this paper is studying the present status of submarine cables and the causes of cable faults, and suggesting techniques and regulations to protect from the trouble of submarine cables.