• Structural Engineering and Mechanics
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• 제35권2호
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• pp.205-215
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• 2010

Recently, earthquake proof technology has been widely applied to both new and existing structures and bridges. The analysis of bridge systems equipped with structural control devices, which possess large degrees of freedom and nonlinear characteristics, is a result in time-consuming task. Therefore, a piecewise exact solution is proposed in this study to simplify the seismic mitigation analysis process for bridge systems equipped with sliding-type isolators. In this study, the simplified system having two degrees of freedom, to reasonably represent the large number of degrees of freedom of a bridge, and is modeled to obtain a piecewise exact solution for system responses during earthquakes. Simultaneously, we used the nonlinear finite element computer program to analyze the bridge responses and verify the accuracy of the proposed piecewise exact solution for bridge systems equipped with sliding-type isolators. The conclusions derived by comparing the results obtained from the piecewise exact solution and nonlinear finite element analysis reveal that the proposed solution not only simplifies the calculation process but also provides highly accurate seismic responses of isolated bridges under earthquakes.

• 대한본초학회지
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• 제20권2호
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• pp.1-6
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• 2005

Objectives : The purpose of this study is to investigate genetic toxicity of Cervi pantotrichum Cornu herbal acupuncture solution(CPCHA). Methods : In this study, a series of investigation have been carried out to analyze the effects of Cervi pantotrichum Cornu herball acupuncture solution(CPCHA) on colony forming ability of NIH3T3cells, Hela cells and adrenorectal coloncell for genetic toxicity test. Results and Conclusions : From the above results, it is suggested that Cervi pantotrichum Cornu herball acupuncture solution(CPCHA) was limited 0.5-10ug/ml by test. Cervi pantotrichum Cornu herball acupuncture solution(CPCHA) did not exert the protective role to the genetic toxicity in kinds of cell lines used in this study. From these results, Cervi pantotrichum Cornu herbal aqua-acupuncture solution needs further study to prove it's function in cell culture system.

• Journal of Chest Surgery
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• 제15권1호
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• pp.35-39
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• 1982

Cold blood potassium cardioplegia, by two types of the infusion systems, was used in 45 patients who were undergone the open cardiac operation. Method A [in 25 patients] was the syringe infusion system and method B [in 20 patients] was the pump infusion system. Cold blood potassium cardioplegic solution was used less amount on method B than method A. Serum potassium was often increased significantly on method A as a result of excessive infusion of cold blood potassium cardioplegic solution. But method B, excessive infusion of cold blood potassium cardioplegic solution was prevented by reperfusion of the previous infused cold blood potassium cardioplegic solution through the recirculation system. Alteration of infused rate and concentration of potassium in cold blood potassium cardioplegic solution during infusion [which might be suggested on the method A] could be controlled on method B.

• Journal of Biosystems Engineering
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• 제20권4호
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• pp.383-389
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• 1995

This study was conducted to develop an automatic nutrient control system for trickle application of nutrient solution. Temperature, electric conductivity(EC). pH and dissolved oxygen(DO) were selected as control variables. A controller using single-chip microcomputer was constructed. An automatic control system for nutrient solution and a controller using single-chip microcomputer with control algorithm were developed. The control system was tested, and could control temperature, EC and pH within the error ranges of $pm 0.2^{circ} pm 0.2mS/cm, pm 0.1pH$, respectively.

• 대한안전경영과학회지
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• 제6권4호
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• pp.227-238
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• 2004

This development has tried to scheme out the convenience for users to use the 3D modeling solution which is developed from the existing programs. The extended 3D modeling solution, to be developed through the use of the API which is provided and Microsoft Access, database is able to reuse the parts, subassemblies of parts, and assemblies. A methodology exhibits the possibility to use a Spinfire Professional Spinfire Reader program. The web evaluation system, which is used to connected with the Internet explorer and to construct a web service, will repeat the evaluations of the company staffs and customers about the new products which the company have designed. The furniture manufacturing company will adopt the 3D modelling solution in modelling the new products and go through the web evaluation system to collect dissatisfied facts of the customers or the company staffs against the new product. Finally, it will contribute to the enormous benefit creation of the enterprise.

• 한국소음진동공학회논문집
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• 제26권7호
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• pp.795-805
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• 2016

Nonlinear normal modes(NNMs) is a branch of periodic solution of nonlinear dynamic systems. Determination of stable periodic solution is very important in many engineering applications since the stable periodic solution can be an attractor of such nonlinear systems. Periodic solutions of nonlinear system are usually calculated by perturbation methods and numerical methods. In this study, numerical method is used in order to calculate the NNMs. Iteration of the solution is presented by multiple shooting method and continuation of solution is presented by pseudo-arclength continuation method. The stability of the NNMs is analyzed using Floquet multipliers, and bifurcation points are calculated using indirect method. Proposed analyses are applied to two nonlinear numerical models. In the first numerical model nonlinear spring-mass system is analyzed. In the second numerical model Jeffcott rotor system which has unstable equilibria is analyzed. Numerical simulation results show that the multiple shooting method can be applied to self excited system as well as the typical nonlinear system with stable equilibria.

• 동력기계공학회지
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• 제15권2호
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• pp.55-60
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• 2011

The popularity of diesel engines is derived primarily from their higher thermal efficiency resulting from higher compression ratio. NOx removal from the diesel emissions is very important to meet stringent emission regulations. NOx emission from diesel engines is removed by an urea-SCR or an LNT system. The urea-SCR system needs the urea-solution supply system with concentration and level sensor. This study was carried out to develop a sensor for the measurement of urea-solution concentration by an electric conductivity method. Considering experimental parameters were the material of electrode, two kinds of electric power(AC or DC), the distance between two electrodes, and the length of electrode. It was found that the AC electric power was more useful to measure the urea-solution concentration compared to DC, because it prevented an ionization of the urea-solution. The silver rod coated with Pt is the most useful electrode, tendency of which is similar to Pt rod, and the cost is more economic. We could also find out the optimum distance between two electrodes and the length of electrode was 10mm and 3mm, respectively.

• 한국표면공학회지
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• 제47권4호
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• pp.174-180
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• 2014

In this study, TiAlSiN coatings have been successfully synthesized on stainless steel and tungsten carbide substrate by a hybrid coating method employing a cathodic arc and a magnetron sputtering source. TiAl and Si target were vaporized with the cathodic arc source and the magnetron sputtering source, respectively. Process gas was the mixture of nitrogen and argon gas. With the increase of Si content, the crystallinity and the grain size of TiAlSiN film was decreased. At the Si content of more than 8 at.%, grain size of TiAlSiN was saturated at around 2 nm. The hardness value of the TiAlSiN film increased with incorporation of Si, and had the maximum value of ~ 3,233 Hv at the Si content of 9.2 at.%. The oxidation resistance of TiAlSiN film was enhanced with the increase of Si content.

• 한국콘텐츠학회논문지
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• 제5권6호
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• pp.360-367
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• 2005

인터넷의 보급으로 인해 기업의 전산화가 발전함에 따라, 바이러스, 전산망 침해 등 정보화의 역기능도 크게 증가하고 있다. 따라서 오늘날, 기업 보안의 중요성이 매우 강조되고 있다. 이렇게 보안의 중요도가 높아짐으로 인하여 보안 솔루션도 함께 발전하고 있다. 보안 솔루션은 기존 단일 체제에서 통합 보안 관리 시스템으로 발전하고 있으며 통합보안관리 시스템에서 중요한 것은 각 보안 솔루션의 기능과 정책 의 적합한 설계이다. 기존의 보안 정책은 외부의 침입으로 부터의 보안을 중요시 해왔으나 현재는 내부의 보안도 그 중요도가 높아지고 있다 이를 위하여 새로운 구조의 통합 보안관리 시스템을 구축해야 한다. 본 논문에서는 침입탐지차단 시스템을 활용하여 내부보안을 강화한 통합 보안 관리 시스템을 제안, 구현하였으며. 내 외부의 IP와 ID접근을 실험하여 그 결과를 분석하였다.

• 한국산학기술학회논문지
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• 제10권8호
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• pp.2044-2054
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• 2009

ERP(Enterprise Resource Planning)는 제조 자원의 효율적 관리를 목적으로 하는 MRP(Material Requirement Planning)로부터 발전한 전사적 자원관리 시스템이라 할 수 있다. ERP 솔루션 분야는 최근까지 국내 솔루션 업체들이 주도해 왔으나 외산 솔루션 업체들이 본격 진출하면서 기업용 애플리케이션 업계의 격전지가 되었다. 이로 인해 국내 업체의 지속적인 품질 향상 노력이 요구되고 있다. 본 연구에서는 ERP 시스템 중, 건설 분야 ERP 시스템에 초점을 맞추어 품질향상을 위한 품질측정 방법으로서 품질특성 체계와 품질측정을 위한 척도를 개발하고 적용사례를 통해 효과적인 평가 방법을 제시하였다. 본 연구 결과를 건설 분야 EPR 시스템의 품질측정에 적용함으로써 품질향상에 기여할 수 있기를 기대한다.