• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.11
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• pp.1545-1550
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• 2014

Fault detection and diagnosis (FDD) of photovoltaic (PV) power systems is one of significant techniques for reducing economic loss due to abnormality occurred in PV modules. This paper presents a new FDD method against PV power systems by using statistical comparison. This comparative approach includes deviation signals between the outputs of two neighboring PV modules. We first define a binary hypothesis testing under such deviation and make use of a generalized likelihood ratio testing (GLRT) theory to derive its FDD algorithm. Additionally, a recursive computational mechanism for our proposed FDD algorithm is presented for improving a computational effectiveness in practice. We carry out a real-time experiment to test reliability of the proposed FDD algorithm by utilizing a lab based PV test-bed system.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.35-40
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• 2003

Immense quantities of coal combustion by-products are produced every year, and only a small fraction of them are currently utilized. The purpose of this study is to investigate reused techniques of coal to highly economic growth and expansion of country base industry. So, in this study, artificial aggregate was developed to recycle coal ash by non-sintering technique and crush method. And characteristic of developed artificial aggregate was examined. Also, noise barriers using developed artificial aggregate was made by link of development of ECO-construction product and is preparing sound absorption and transmission loss experiment. Result of study was showed that artificial aggregate was more proper to use a noise barriers and this is expected to satisfy sound absorption standard in this study. So, if shape and color considering surround and design technology is studied continuously, it can be expected to make ECO-precast product as well as maximize waste recycling.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.2
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• pp.231-238
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• 2003

The fuel of light water reactor is used for several years under high temperature and pressure, so it needs to be clad with high corrosion resistance material. The cladding materials must have the characteristics of low absorption of a neutron and high corrosion resistance. Zircaloy-2 in Boiling Water Reactor, Zircaloy-4 in Pressurized Water Reactor have been used as cladding materials and Zirlo has been developed as the material for preventing the corrosion. If the fracture of the cladding tube occurs during operation, it will cause the economic loss to shut down and replace the system. So it is needed to evaluate the integrity of the cladding materials. In this paper, the tensile characteristics of the cladding materials were investigated for the basic research of fracture characteristics. Also the residual stress was analyzed to compare the tube type(original type) specimen and the flattened type specimen.

• Korean Journal of Veterinary Service
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• v.22 no.1
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• pp.9-13
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• 1999

Mycoplasmal pneumonia of swine(MPS) cause by Mycoplasma hyopneumoniae has been recognized as a serious impediment to swine production due to chronic respiratory disorder which result in the weight loss and decreased feed conversion. The disease causes a great economic losses in pig industry by characterizing with high morbidity, low mortality, growth retardation and low feed efficiency. The present study was conducted to investigate the titers of antibody against M hyopneumoniae from the regional and seasonal groups of the slaughtered pigs by enzyme-linked immunosorbent assay(ELISA). The result have shown that the average seropositive rate of M hyopneumoniae infection was 84.6% . The regional seropositive rate in Korea showed 87.4% in Kyonggj, 83.4n in Kangwon, 89.2% in Chungnam and 77.6% in Chungbuk area, respectively. Also the seasonal seropositive rate was appeared as 78.6% in spring,90.1% in summer, 76.9% in autumn and 83.8% in winter, respectively.

• Korean Journal of Veterinary Research
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• v.33 no.3
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• pp.555-565
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• 1993

The studies on the liver fluke of Korea have been reviewed. The fluke is Fasciola hepatica. Its intermediate host is Lymnaea biridis, whose principal habitats are rice paddies. The first fascioliasis of Korean native(beef) cattle was reported in 1915. Bovine fascioliasis is present throughout the conuntry, including north Korea, with the average prevalence of 30%. The prevalence of the disease is about the same in dairy cattle, which have been imported from other countries since 1960s. The disease was also found in Korea in other species of animals such as sheep, goats, deer of zoo and farms, and guinea pigs of a laboratory. Human fascioliasis was reported ; 35 cases by fecal examination and 11 by both parasitology and pathology. Of the latter 11 cases, 5 were ectopic parasitism. Economic loss due to the reduced carcass weight and milk production, and liver condemnation was great. Almost all flukicides developed in other countries are commercially available in Korea.

• Journal of the Korean Society of Safety
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• v.21 no.1 s.73
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• pp.1-5
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• 2006

The damage of important equipments for the nuclear power plant by the earthquake brings the loss of human lives and economic losses. Therefore safety-related equipment of nuclear power plant must be proved that function must be designed and structural integrity so that it can be maintained also from accident condition of various kinds. In this study, the computer room air conditioner to be delivered at the nuclear power plant applied to this qualification, try to develop an optimum model. This model ended up with good results which were under suitably allowable conditions about structurally safe earthquake.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2008.10b
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• pp.164-169
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• 2008

The increasing late-payment rate of credit card customers caused by a recent economic downturn are incurring not only reduced profit of department stores but also significant loss. Under this pressure, the objective of credit forecasting is extended from presumption of good or bad customers to contribution to revenue growth. As a method of managing defaults of department store credit card, this study classifies credit delinquents into some clusters, analyzes repaying patterns of customers in each cluster, and develops credit forecasting system to manage delinquents of department store credit card using data of Korean D department store's delinquents. The model presented by this study uses Kohonen network, a kind of artificial neural network of data mining techniques to cluster credit delinquents into groups. Logistic regression model is also used to predict repayment rate of customers of each cluster per period. The accuracy of presented system for the whole clusters is 92.3%.

• Transactions of the Korean hydrogen and new energy society
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• v.22 no.1
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• pp.29-34
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• 2011

This study examined the effect of environmental variables, such as the NaOH concentration and solution temperature, on the rate of hydrogen generation from NaOH solutions through the corrosion of used aluminum cans as a potential candidate material for the safe and economic production of hydrogen. Corrosion of the used aluminum cans was promoted by increasing the NaOH concentration and solution temperature because of the loss of aluminum passivity. The measured rate of hydrogen generation from the NaOH solutions increased with increasing NaOH concentration due to the catalytic activity of NaOH in the hydrolysis process. However, at higher solution temperatures, the rate of hydrogen generation rate was less affected by the NaOH concentration than that at lower temperature.

• Proceedings of the KIEE Conference
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• 2001.11b
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• pp.9-14
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• 2001

On the side of that necessity, it is known that the development of Amorphous metal take effects on lowering eddy current loss in a core system. If a amorphous transformer and a motor to which "Amorphous Metal" is applied be widespread, electricity saving should be enormous with the several hundreds billion won of economic effects like cutting the cost of power plants and the unhealthy gases. This paper carried out general evaluation about the characters of Amorphous metal, the expected energy saving effects of a amorphous transformer, the environmental contribution, the increasement of electricity quality, and the features of harmonic.

• Proceedings of the KIEE Conference
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• 1997.07b
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• pp.550-554
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• 1997

It is important to select a reliable electronic control system in power plants because a trip of a power plant caused by malfunction of the control system can lead to a great deal of economic and social loss. In this paper. environmental test specifications for evaluating the reliability of the electronic control system were developed in order to select a reliable one. Also, the electronic control systems made by domestic manufacturers were tested based on these developed environmental test specifications.