• 인터넷정보학회논문지
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• 제15권3호
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• pp.91-100
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• 2014

IT 보안의 중요성으로 인해 IT 보안 솔루션의 성능 및 기업의 보안에 대한 투자는 꾸준히 증가하고 있지만, 보안 사고 발생으로 인한 기업의 금전적 손실 감소는 여전히 기대에 미치지 못하고 있는 상황이다. 보안 솔루션을 운영하고 있는 기업을 상대로 한 조사 결과에 따르면, 기업의 보안 솔루션에 대한 이해 부족과 잘못된 투자 전략이 기업의 투자 대비 보안 효율성 향상을 기대에 미치지 못하게 하는 주요한 원인으로 분석되었다. 본 논문에서는 기업의 보안 솔루션에 대한 잘못된 투자로 인한 투자 대비 보안 효율성 저하 문제를 해결하기 위한 보안 투자 결정 모델을 제안한다. 구체적으로는, IT 자산의 취약성 이용 공격으로 인한 조직의 피해 발생 이전에 보안 사고 예방이 가능한 사전 보안 솔루션(Proactive Security Solutions, PSSs)과 조직의 피해 발생 이후에 보안 사고를 조사 및 분석할 수 있는 사후 보안 솔루션 (Reactive Security Solutions, PSSs)에 대한 기업의 투자 방법론을 결정하기 위한 포괄적인 수학적 모델을 제안한다. 또한, 제안된 분석 모델을 사용하여 보안 솔루션의 다양한 매개 변수 영향력 아래에서 조직의 IT 보안 투자 예상 순 이익(expected net benefit)을 극대화하기 위한 최적의 방안을 모색한다.

• Bulletin of the Korean Chemical Society
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• 제31권12호
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• pp.3573-3578
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• 2010

Recently it is suggested that it may be possible to obtain the approximate or exact bound state solutions of nonrelativistic Schr$\ddot{o}$dinger equation from relativistic Klein-Gordon equation, which seems to be counter-intuitive. But the suggestion is further elaborated to propose a more detailed method for obtaining nonrelativistic solutions from relativistic solutions. We demonstrate the feasibility of the proposed method with the Morse potential as an example. This work shows that exact relativistic solutions can be a good starting point for obtaining nonrelativistic solutions even though a rigorous algebraic method is not found yet.

• 한국IT서비스학회지
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• 제2권1호
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• pp.85-97
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• 2003

This research has designed and implemented the standard conformance test system for e-Business solutions that supports the ebXML, which is currently being focused on as the leading electronic commerce framework. The adoption of standards such as ebXML is probably the best way to achieve interoperability among electronic commerce systems, and more and more e-Business solutions around the world are supporting ebXML. This research primarily discusses the concept and needs for the standard conformance tests on e-Business solutions. The standard conformance test system is developed based on the detailed specifications of the ebXML framework. This system was used to test commercial e-Business solutions supporting ebXML. The system implemented in this research will provide a significant basis for the standard conformance certification of e-Business solutions, and could also provide clear decision criteria for e-Business solutions currently in market, thus activate the overall e-Business market.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 춘계학술대회 논문집
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• pp.363-368
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• 1995

A general method of solving inverse kinematics of three-joint manipulator composed of revolute joints or prismatic joints or combinations of those joints is presented in this study. In completing real-time control, it is very important to obtain the closed form solutions of inverse kinematics rather than iterative numerical solutions, because iterative numerical solutions are generally much slower than the corresponding closed form solutions. If it is possible to obtain the inverse kinematic solutions for general cases of considering twist anlges and offsets, the manipulator work space can be designed and enlarged more effciently for specific task. Moreover, in idustrial manipulators, the effect of main three joints is larger than that of the other three joints related to orientation in the view of work space. Therfore the solutions of manin three-joint are considered. Even The inverse kinematic equations are complicatedly coupled, the systematical solving process by using symbolic calculation is presented.

• 산업공학
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• 제23권1호
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• pp.1-11
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• 2010

There are various ways to manage the patient flow of the hospital outpatient system. However, it is difficult to apply many implementation solutions to the real outpatient system at once. Because first, the expected effects of each different solution are very much depend on the real situation of the system and applied other solutions, and second, owing to the limited resources, each solution should be implemented according to the priority. In order to overcome these difficulties, this paper focuses on proposing the comprehensive subset of implementation solutions, which is one of the most effective among various kinds of subsets, and verifying the effects of it. The comprehensive subset of solutions is derived from conducting design of experiments and simulation which determine the optimum set of different solutions and analyze the particular interactions and priority order among them. This implementation strategy can solve the difficulties of applying different kinds of various solutions to the hospital outpatient system.

• 대한수학회보
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• 제51권6호
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• pp.1697-1710
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• 2014

The initial-boundary value problem for a class of nonlinear higher-order wave equations system with a damping and source terms in bounded domain is studied. We prove the existence of global solutions. Meanwhile, under the condition of the positive initial energy, it is showed that the solutions blow up in the finite time and the lifespan estimate of solutions is also given.

• 호남수학학술지
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• 제24권1호
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• pp.35-41
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• 2002

The solutions of a homogeneous system in state space form $\dot{x}=Ax$ are to the form $x=e^{At}x_0$ and the solutions of an inhomogeneous system $\dot{x}=Ax(t)+f(t)$ are to the form $x=e^{At}x_0+{{\int}_0^t}\;e^{A(t-{\tau})}f({\tau})d{\tau}$. In this note we show that the solution of descriptor systems under some conditions exists, and is unique, moreover it is interesting to know the solutions of descriptor system are schematically like the solutions as in the state space form. Also we will give some algorithms to compute these solutions.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제26권1호
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• pp.49-66
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• 2022

The G-Euler process has been proposed to overcome the difficulties of the calculation of the exponential function of the Jacobian. It is an explicit method that uses the exponential function of the scalar skew-symmetric matrix. We define the moving shapes of true solutions and the moving shapes of numerical solutions. It is discussed whether the moving shape of the numerical solution matches the moving shape of the true solution. The match rates of these two kinds of moving shapes are sequentially calculated by the G-Euler process without using the true solution. It is shown that the closer the minimum match rate is to 100%, the more closely the numerical solutions follow the true solutions to the end. The minimum match rate indicates the reliability of the numerical solution calculated by the G-Euler process. The graphs of the Lorenz system in Perko [1] are different from those drawn by the G-Euler process. By the way, there is no basis for claiming that the Perko's graphs are reliable.

• Journal of Advanced Marine Engineering and Technology
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• 제13권2호
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• pp.43-63
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• 1989

Various kinds of corrosion prevention methods have been developed. It is known that the method of electrochemical protection is more effective and economical than any other method on the large scale metal structures in corrosive solutions. Strong acid solutions such as nitric and sulfuric acid solutions are often used in industries, and the expensive stainless steel is almost exclusively used for the equipment that comes in contact with such acid solutions. However, it is more reasonable that carbon steel is used rather than stainless steel depending upon concentration of those acid solutions from the economical viewpoint. In this study, the typical strong acid solution such as nitric and sulfuric acid solutions are chosen for the experiment and the selected materials of specimen are the stainless steels of SUS 304L and SUS 316L, the carbon steels of SS 41, SM 50 and RA 32, and highly pure lead. Electrochemical protection diagrams can be drawn with data from the external cathodic and anodic polarization curves of SUS 304L, SUS 316L and SM 50 steels in 5-60% nitric acid solutions and from those polarization curves of SS 41, RA 32, SM 50 and SUS 316L steels, and highly pure lead in 2.5-98% sulfuric acid solutions at the slow scanning rate. The data obtained with using the determination method of the optimum cathodic protection potential, the Tafel extrapolation method and the characteristics of anodic polarization curves. The main results obtained from the diagrams are as follows: 1) In nitric acid solution : (1) Corrosion potentials exist in each of those corrosion zones on the stainless steels in the lower concentration than about 12% solutions and on the high tensile strength steels in the lower concentration than about 30% solutions, but the corrosion current (density) in each zone is small on the above mentioned former steels and large on the latter ones. (2) The stainless steels can be self-passivated in the higher concentration than 15% solutions, and the high tensile strength steels gives rise to the same phenomenon in the higher concentration than 35% solutions. (3) The stainless steels in the lower concentration than 60% solutions and the high tensile strength steels in the higher concentration than 35% solutions can be used without protection, but the latter steels must ve protected anodically in the lower conccentration than about 30% solutions. 2) In sufuric acid solution : (1) The carbon steels can be self-passivated in the higher concentration than 45% solutions, and the SUS 316L steel in higher concentration than 75% solutions and the lead in all concentration solutions also gives rise to the same phenomenon. (2) The lead in the lower concentration than 80% solutions and the SUS 316L steel in the higher concentration than 80% solutions can be used without protection. (3) The carbon steels in the higher concentration than 50% solutions also can be used without protecting economically, but the SUS 316L steel in the 20-70% solutions are considerably corrosive without protecting anodically.

• 대한수학회지
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• 제37권5호
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• pp.871-884
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• 2000

Polyharmonic operator with Dirichlet boundary condition is considered in a n-dimensional cone. The regularity properties of weak solutions are studied. In particular, it is proved the Holder contionuity of solutions near the vertex of the cone for dimensions n=2m+3,2m+4, where 2m is the order of the polyharmonic operator.