• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.2100-2101
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• 2008

This paper is studied on a protective control system for electrical fire and electrical faults due to over current or electric short circuit faults by using electrical thermal characteristics of PTC (Positive Temperature Coefficient) thermistor and current response characteristics of high sensitive reed switch. The PTC thermistor has characteristic of positive resistivity temperature coefficient according to the temperature variation, which is construction of a regular square and cube demarcation with BaTiO3_Ceramics of positive temperature coefficient. Also PTC thermistor shows the phenomenon which is rapidly increased in the resistivity if the temperature is increased over Curie temperature point, and reed switch, which is used for electrical fault current sensing devices, have a excellent characteristic of response velocity in degree of ${\mu}s{\sim}ms$ that sensing magnetic flux in proportion to dimension of line current. This paper is proposed on a protective control system use PTC thermistor and reed switch for sensor which is protected from electrical fire due to overload faults or electric short circuit faults. Some experimental results of the proposed electric safety control device are confirmed to the validity of the analytical results.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.2102-2103
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• 2008

The major causes of electrical fire are classified to short circuit fault, overload fault, electric leakage and electric contact failure. The occurrence factor of the fire is electric arc or spark accompanied with electrical faults. Residual Current Protective Device(RCD) of high sensitivity type used at low voltage wiring cuts off earth leakage and overload, but the RCD can't cut off electric arc or spark to be a major factor of electrical fire. As the RCDs which are applied low voltage distribution panel are prescribed to rated breaking time about 30[ms](KS C 4613), the RCDs can't perceive to the periodic electric arc or spark of more short wavelength level. To be improved on such problem, this paper is proposed to a electrical fire disaster prevention device(EFDPD) for a RCD trip or a self circuit-breaking function on electric arc or spark due to electrical fire. Some experimental results of the proposed apparatus is confirmed to the validity of the analytical results.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.922-923
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• 2008

This paper is proposed to a novel DC-DC buck-boost converter added electric isolation by using a soft switching method. To be achieved of high efficiency system, the proposed converter is constructed by using a partial resonant circuit. The control switches using in the converter are operated with soft switching for a partial resonant method. The controlling switches are operated without increasing their voltage and current stresses by the soft switching technology. The result is that the switching loss is very low and the converter efficiency is high. And the proposed converter is added in a electric isolation. When the power conversion system is required to electric isolation, the proposed converter is adopted with system development of high efficiency. The soft switching operation and the system efficiency of the proposed converter is verified by digital simulation and experimental results.

• Proceedings of the KIPE Conference
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• 2010.07a
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• pp.107-108
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• 2010

Uncertainty and insecurity is a serious issue in all aspects of our society today as the change in environmental and societal conditions became more apparent than ever before through various disasters. Thus, it is now an important point in time for the government and responsible firms to implement an innovative scientific disaster management method that can lead to establishing a more secure and stable future. Therefore, authors have developed ubiquitous- based disaster prevention automation system(DPAS). The system would follow up after sensors detecting fires, thefts, torrents, floods, and infrastructural leaks. It prevents disasters in advance by utilizing a wireless communications net or ethernet to conduct real-time monitoring from a remote place. The system also has an advantage as it is designed in a compact size that applies a precision-focused programmable logic controller(PLC) of one-chip type.

• Proceedings of the KIEE Conference
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• 2008.10c
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• pp.142-144
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• 2008

This paper is studied on the characteristic analyses of a high performance buck-boost converter added electric isolation by using a soft switching method. To be achieved of a high performance system, the proposed buck-boost converter is constructed by using a partial resonant circuit. The control switches using in the converter are operated with soft switching for a Partial resonant method. The controlling switches are operated without increasing their voltage and current stresses by the soft switching technology. The result is that the switching loss is very low and the converter efficiency is high. And the proposed converter is added in a electric isolation. When the power conversion system is required to electric isolation, the proposed converter is adopted with the system development of high efficiency. The soft switching operation and system efficiency of the proposed converter is verified by digital simulation and experimental results.

• Korean Journal of Environmental Biology
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• v.24 no.1 s.61
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• pp.29-37
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• 2006

We investigated the feeding habits of Rhynchocypris kumgangensis in Hongcheon River of Saenggokri, Seoseokmyeon, Hongcheongun, Gangwon-do, Korea from April 2002 to March 2003. The fish is korean endemic species upper streams in Korea. It was asscertained that R. kumgangensis is a carnivore and consumes mainly Ephemeroptera, Diptera, Terrestrial insects and Trichoptera. The most important prey was chironomids: Chironomus sp. Their feeding habits changed according to growth. Small fish fed mainly on small prey organisms such as Diptera, while larger fish fed much more on Ephemeroptera and Terrestrial insects. There were also seasonal changes in the relative proportion of their food items.

• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.435-437
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• 2007

Authors propose a PFC(power factor correction) Buck-Boost AC-DC converter by soft switching method. The proposed converter for a discontinuous conduction mode eliminates the complicated control requirement and reduces the size of components. The input current waveform in the converter is got to be a sinusoidal form of discontinuous pulse in proportion to magnitude of ac input voltage under the constant duty cycle switching.Therefore,the input power factor is nearly unity and the control algorithm is simple. To achieve high efficiency system, the proposed converter is constructed by using a partial resonant technique. The control switches using in the converter are operated with soft switching for a partial resonant. The control switches are operated without increasing their voltage and current stresses by the soft switching method. The result is that the switching loss is very low and the efficiency of converter is high.

• Proceedings of the KIEE Conference
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• 2009.04b
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• pp.266-268
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• 2009

In this paper, authors deal with a power conditioning system (PCS) of high efficiency for a proton exchange membrane fuel cell (PEMFC) generation system. Fuel cells are a direct current (DC) power generators. They generate electricity through an electrochemical process that converts the energy stored in a fuel directly into electricity. Fuel cells have many benefits, which produce no particulate matter, nitrogen or sulfur oxides. And they have few moving parts and produce little or no noise. When fueled by hydrogen, they yield only heat and water as byproducts. Their wide application can reduce our dependence on fossil fuels and foreign sources of petroleum. This paper studies on a novel PCS circuit topology of high efficiency using in PEMFC generation system The controlling switches in the PCS is operated to soft switching. Some digital simulation results and experimental results for the proposed PCS is confirmed to the validity of the analytical results.

• Korean Journal of Veterinary Service
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• v.33 no.4
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• pp.401-409
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• 2010

From 2006 through 2007, the highest need for the most urgent attention in Gangwon-do Wild Animal Rescue Center was wildlifevehicle collisions (WVC). The Korean Ministry of Environment reported 6543 WVC's in 2005 and 5565 cases of WVC's in 2006. In this study, data from the Gangwon-do Wild Animal Rescue Center was utilized to analyze WVC incidents and the movement of wildlife near roadways in Korea. From 2006 through the first half of 2008, the portable GPS device recorded accident location of the injured wildlife. Attempts were made to track and monitor the movements of four raccoon dogs and five Korean water deers near the roads. One raccoon dog and one Korean water deer were successfully tracked and monitored. Their locations were transmitted to cell phones. The amount of WVC's was highest amongst the roads near the forests of Gangwon-do. The devices installed on the nearby roads did not protect the wildlife from WVC's. Results using the CDMA-type GPS collar showed that wildlife often crossed the road even with devices installed to prevent this from crossing roads. This research analyzed the behaviors of different wildlife animals and WVC's. New preventative measures need to be established to avoid roadkill. It is suggested that new streets be built or for an appropriate speed limit be implemented.

• Korean Journal of Veterinary Research
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• v.29 no.4
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• pp.525-530
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• 1989

In order to enumerate the T-lymphocytes in bovine peripheral blood lymphocytes (PBL) by E rosette assay, KGRBC were treated with various concentrations of 2-aminoethylisothiouronium bromide(AET) and dextran(Dex), singly or in combination. To further standardize the assay, optimum concentration of AET- and/or Dex-treatment and incubation time for rosette forming cell(RFC) counts were determined. The levels of B-lymphocytes in the PBL were evaluated by erythzocyte-antibody($EA_{Fc}$)- and erythrocyte-antibody-complement (EAC)-rosetting techniques. The results obtained were as follows; The PBL from 20 clinically normal Korean cattle were formed as low percentage of spontaneous E-rosette ($6.7{\pm}2.4%$) in control group, whereas in KGRBC treated with 0.1M AET for 20 minutes and 8% Dex were formed as $37.3{\pm}2.7%$ and $45.1{\pm}2.1%$, respectively. And the synergistic effects were noted no less than $66.5{\pm}5.6%$ when the KGRBC treated with 0.1M AET and 8% Dex subsequently and rate of RFR did not change significantly between 3~24 hours incubation time at $4^{\circ}C$, EA-and EAC-RFR were $23.3{\pm}9.1%$ and $23.1{\pm}7.9%$, respectively. These results suggest that the KGRBC would be a useful agent for the enumeration of T-lymphocytes by E rosette assay and B-lymphocytes by EA- or EAC-rosette assay in cattle-PBL.