• 한국산업융합학회 논문집
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• 제4권3호
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• pp.263-266
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• 2001

In this paper, intelligent methods using digital protection relay in power SCADA system is developed in order to protect power systems by means of timely fault detection during operation and control at starting for induction motor which have various load environments and capacities in power systems. The digital protective relay was designed with DSP CPU(TMS320C31) to protect and measure more quickly and precisely. The test result on the basis of KEMC 1120 and IEC60255, show that the operation time error of the digital motor protection relay is improved within ${\pm}5%$. Also, we can control motors at starting according to starting types with simple method as programmable sequence editor. So we can improve the demerits of high cost and much manhour for rework.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2018년도 춘계 학술논문 발표대회
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• pp.224-225
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• 2018

Modern people are more interested in the indoor environment as they spend more time indoors than in the past. Among the air pollutants in the indoor air, ladon gas is a colorless, tasteless, odorless, inert gas produced by nuclear decomposition of naturally occurring uranium in rocks and soils. It has been proven that ladon gas is introduced into the room through cracks on the floor of the building or basement wall, and it causes various diseases such as lung cancer when exposed to radon during human breathing. The US Environmental Protection Agency (EPA) specifies 4pCi / L as a necessary measure for radon, and the Korea Environmental Protection Agency has implemented comprehensive indoor radon management measures since 2007. Therefore, in this study, we intend to adsorb and reduce radon in indoor air pollutants.

• Journal of Radiation Protection and Research
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• 제42권1호
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• pp.21-25
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• 2017

Background: We are developing L-band and S-band microwave dielectric absorption systems aiming novel dosimetry using DNAs, such as plasmid DNA and genomic DNA, and microwave technology. Materials and Methods: Each system is composed of a cavity resonator, analog signal generator, circulator, power meter, and oscilloscope. Since the cavity resonator is sensitive to temperature change, we have made great efforts to prevent the fluctuation of temperature. We have developed software for controlling and measurement. Results and Discussion: By using this system, we can measure the resonance frequency, f, and ${\Delta}Q$ (Q is a dimensionless parameter that describes how under-damped an oscillator or resonator is, and characterizes a resonator's bandwidth relative to its center frequency) within about 3 minutes with high accuracy. Conclusion: This system will be expected to be applicable to DNAs evaluations and to novel dosimetric system.

• 방재기술
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• 통권19호
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• pp.22-28
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• 1995

The rate of heat release is probably the single most important measure of fire hazard. Several tech-niques were developed for the measurement of rate of heat release, but were not suitable for fire test-ing purpose. Recently the application of oxygen consumption principle made it possible to development of well-characterized heat release rate measurement apparatus, the furniture calorimeter for large-scale fire tests and the cone calorimeter for bench-scale fire tests. The cone calorimeter can be used to determine the ignitability as well as heat release rate and smoke development, mass loss rate, combustion gas production etc. from burning materials. Thus, test method using cone calorimeter, an internationally recognized and accepted for the evalua-tion of fire properties, is a very promising tool for combustion study on various kind of materials and products.

• 식품과학과 산업
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• 제51권3호
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• pp.196-208
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• 2018

This paper described the contents of the WTO (world trade organization) SPS (world trade organization) Agreement and trends in the WTO SPS provisions such as equivalence, localization, transparency, and risk assessment. The purpose of the WTO SPS agreement is to promote international trade by preventing arbitrary and unreasonable use of SPS measures, which are the rights of a country for the protection of human health and animal and plant health, and by abolishing the non-tariff barriers. To this end, the requirements for implementing the SPS measures taken by the importing country are restricted to those that can scientifically prove to be inevitable for SPS protection. The major provisions in WTO SPS agreement were elaborated to promote international trades. When trade-restricted SPS measures such as prohibition of imports are made, a scientific basis should be provided. Therefore, it is essential to provide scientific evidence based on risk analysis to protect people's health from potentially harmful imported foods.

• 한국항행학회논문지
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• 제15권5호
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• pp.801-807
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• 2011

본 대부분의 기업들은 업무 프로세스가 전산화되어 있기 때문에 전산장애나 재해로 인해 시스템이 다운되면 기업의 신뢰성과 사업의 연속성에 치명적인 악영향을 미칠 수 있다. 이에 따라 기업에서는 데이터 손실이 없는 비즈니스 연속성에 대한 관심이 고도화되는 실정이다. 본 논문에서는 시스템 장애를 물리적 장애와 논리적 장애로 분리하여 정의하고 실시간 데이터백업에 필요한 IOPS 성능을 개선하기 위한 Flash SSD를 이용하는 CDP 시스템을 제안하였다. Flash SSD를 사용한 CDP의 IOPS 성능을 측정하기 위하여 실험 시스템을 구성하고, 블록크기의 변화에 따른 IOPS를 실험한 결과, Flash SSD를 이용한 CDP 시스템의 IOPS 성능이 S-ATA에 비해 약 50배 향상되는 것으로 확인하였다.

• Corrosion Science and Technology
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• 제6권6호
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• pp.269-274
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• 2007

The corrosion of steel in concrete is significant in marine environment. Salt damage is one of the most detrimental causes to concrete bridges and port structures. Especially, the splash and tidal zones around water line are comparatively important in terms of safety and life-time point of view. During the last several decades, cathodic protection (cp) has been commonly accepted as an effective technique for corrosion control in concrete structures. Zn-mesh sacrificial anode has been recently developed and started to apply to the bridge column cp in marine condition. The detailed parameters regarding Zn-mesh cp technique, however, have not well understood so far. This study is to investigate how much Zn-mesh cp influences along the concrete column at elevated temperature. About 100 cm column specimens with eight of 10 cm segment rebars have been used to measure the variation of cp potential with the distance from Zn-mesh anode at both $10^{\circ}C$ and $40^{\circ}C$ in natural seawater. The cp potential change and current diminishment along the column specimens have been discussed for the optimum design of cp by Zn-mesh sacrificial anode.

• International Journal of Naval Architecture and Ocean Engineering
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• 제6권4호
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• pp.826-839
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• 2014

Fire is a continuous threat to FPSO topside modules as large amounts of oil and gas are passing through the modules. As a conventional measure to mitigate structural failure under fire, passive fire protection (PFP) coatings are widely used on main structural members. However, an excessive use of PFP coatings can cause considerable cost for material purchase, installation, inspection and maintenance. Long installation time can be a risk since the work should be done nearly at the last fabrication stage. Thus, the minimal use of PFP can be beneficial to the reduction of construction cost and the avoidance of schedule delay. This paper presents a few case studies on how different applications of PFP have influence on collapse time of a FPSO module structure. A series of heat analysis and thermal elasto-plastic FE analysis are performed for different PFP coatings and the resultant collapse time and the amount of PFP coatings are compared with each other.

• 한국IT서비스학회지
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• 제14권3호
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• pp.131-146
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• 2015

The communications market can be characterized for its overflow of users, oligopoly business structure, 24/7 open service, incomplete sales, and operation of core platform function. These characteristics have lead users to continuously make complaints and suffer inconveniences, and thus the concept of user protection has come to receive attention. This study aims to propose solutions through communication channeling between businesses and users, based on website construction from the viewpoint of user protection. In particular, a research model was developed to display how the information symmetry of websites can be influential on the satisfaction, reliability, and continuous intention for using communication services. Total of 14 hypotheses were set to measure a significant degree of variables corelation and eight hypotheses were accepted finally. The analysis results showed that information symmetry of telecommunication service websites had a positive effect on intention for continuous usage. Through the research results, it is expected that communication service businesses will be able to consider important factors when constructing websites. Furthermore, the results are expected to be utilized as for ensuring users' continued usage of their communication services.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제48권11호
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• pp.717-723
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• 1999

The transient characteristics of grounding systems play a major role in the protection of power equipments, electronic circuits and info-communication facilities against surges which arise from lightning or ground faults. Electronic devices are very weak against lightning surges injected from grounding systems and can be damaged. The malfunction and damage of electronic circuits bring about bad operation performances, a lot of economical losses, and etc. Therefore, in order to obtain the effective protection measure of electronic devices from overvoltages and lightning surges, the analysis of the transient grounding impedances in essential. One of this work is to examine the transient behaviors of grounding impedances under steplike currents for various grounding systems. And the other of this work is to evaluate the transient behaviors of a grid with rods under impulse currents and to investigate the effect of grounding lead wire. Transient grounding impedances of a grid with rods under impulse current waves have been measured as a parameter of the length of the grounding leads. Z-t, Z-i and V-i curves of transient grounding impedance under impulse current waveforms have been measured and analyzed. It was found that the grounding impedance gives the inductive, resistive and capacitive aspects under steplike current. Transient grounding impedance characteristics were very different with shapes, geometries of ground electrodes. Also, they were dependent on the waveform and magnitude of impulse current.