• Nuclear Engineering and Technology
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• v.46 no.5
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• pp.569-580
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• 2014

Seismic isolation is a viable strategy for protecting safety-related nuclear structures from the effects of moderate to severe earthquake shaking. Although seismic isolation has been deployed in nuclear structures in France and South Africa, it has not seen widespread use because of limited new build nuclear construction in the past 30 years and a lack of guidelines, codes and standards for the analysis, design and construction of isolation systems specific to nuclear structures. The funding by the United States Nuclear Regulatory Commission of a research project to the Lawrence Berkeley National Laboratory and MCEER/University at Buffalo facilitated the writing of a soon-to-be-published NUREG on seismic isolation. Funding of MCEER by the National Science Foundation led to research products that provide the technical basis for a new section in ASCE Standard 4 on the seismic isolation of safety-related nuclear facilities. The performance expectations identified in the NUREG and ASCE 4 for seismic isolation systems, and superstructures and substructures are described in the paper. Robust numerical models capable of capturing isolator behaviors under extreme loadings, which have been verified and validated following ASME protocols, and implemented in the open source code OpenSees, are introduced.

• Solar Energy
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• v.11 no.2
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• pp.29-33
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• 1991

The present paper deals with two types of heating methods widely used for the Radiant Floor heating systems in Korea. Of these, one method circulates hot water according to the predefined schedule ("intermittent heating") while the other runs the system with the aid of thermostats ("continuous heating"). The standard version of SERI-RES has been modified for the numerical simulation of the problem. Preliminary results show relatively large temperature swings in the case of intermittent heating with solar availability. On the other hand, the case of continuous heating would avoid such undesirable temperature fluctuations. These results are also verified by experimental evaluations.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.8 no.3
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• pp.361-374
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• 1996

In general, a cooling tower has two major noise sources, one is the fan and the other is the falling water. The fan noise is produced by passage of its blades through the air and radiates from the fan stack. Noises from the falling water are caused by splashing and dropping of water cascading over the internal filler of the cooling tower and into the basin and radiate from the louvered face. In this paper, the noise measurements and its frequency analysis are carried out for the locations facing the louvered side and near the fan stack referring the related code and standards in order to study the noise characteristics of the induced-draft cooling tower, especially for the buildings. As a result, it is found that for every doubling of distance from the noise source the noise level decreases by 2~4dBA in the near field with reflect surfaces and decreases by about 6dBA also in the far field without reflect surfaces. As a supplement to the noise measurements, a computer program with simple algorithm is developed in order to estimate the noise level at a distance from the cooling tower, so that the user could apply and modify it for the particular boundary conditions easily.

• Earthquakes and Structures
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• v.8 no.3
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• pp.591-617
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• 2015

Standards for seismic assessment and retrofitting of buildings provide deformation limit states for structural members and connections. However, in order to perform fully consistent performance-based seismic analyses of soil-structure systems; deformation limit states must also be available for foundations that are vulnerable to nonlinear actions. Because such limit states have never been established in the past, a laboratory testing program was conducted to study the rotational capacity of small-scale foundation models under combined axial load and moment. Fourteen displacement-controlled monotonic and cyclic tests were performed using a cohesionless soil contained in a $2.0{\times}2.0{\times}1.2m$ container box. It was found that the foundation models exhibited a stable hysteretic behavior for imposed rotations exceeding 0.06 rad and that the measured foundation moment capacity complied well with Meyerhof's equivalent width concept. Simplified code-based soil-structure analyses of an 8-story building under an array of strong ground motions were also conducted to preliminary evaluate the implication of finite rotational capacity of vulnerable foundations. It was found that for the same soil as that of the experimental program foundations would have a deformation capacity that far exceeds the imposed rotational demands under the lateral load resisting members so yielding of the soil may constitute a reliable source of energy dissipation for the system.

• Journal of the Semiconductor & Display Technology
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• v.13 no.4
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• pp.1-5
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• 2014

The plasma density distribution in between the electrode and lateral wall of a narrow gap CCP was investigated. The plasma density distribution was obtained using single Langmuir probe, having two peaks of density distribution at the center of electrode and at the peripheral area of electrodes. The plasma density distribution was compared with the RF fluctuation of plasma potential taken from capacitive probe. Ionization reactions obtained from numerical analysis using CFD-$ACE^+$ fluid model based code. The peaks in two region for plasma density and voltage fluctuation have similar spatial distribution according to input power. It was found that plasma density distribution between the electrode and the lateral wall is closely related with the local ionization.

• The KIPS Transactions:PartD
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• v.8D no.6
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• pp.843-852
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• 2001

Statistics concerning software errors indicate that more errors are introduced in analysis and design phase than implementation phase. Therefore, it is needed to check whether the design modeling is appropriate for own function and structure. This paper discussed the effective test method for the object-oriented design model, i.e., UML. A new method was proposed for generating test data. This method consists of category partition theory by the representation each element in UML model with OCL (Object Constraint Language). Test data generated in this way can be used for testing the source code functionality as well as for checking the design model.

• Journal of the Korean Society of Safety
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• v.26 no.5
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• pp.99-104
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• 2011

An ILRT Interval for a nuclear power plant in Korea was extended from once in five years to once in ten years. Therefore, it is necessary to evaluate risk impact for ILRT interval extensions. In this paper, input data were generated for the reference plants, KSNP, using raw data such as meteorological data, population distribution data and source term data. And, using MACCS II code the risk impact assessment was performed based on the two methodologies of NUREG-1493 and NEI Interim Report. The risk impact derived from an ILRT interval extension was identified not to be significant. It is considered to apply this study and results to making an accident management plan and safety goal, and to the field of public acceptance.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 2003.12a
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• pp.458-462
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• 2003

기존의 고정적 웹 페이지에, 실시간적으로 변화하는 내용의 제공을 가능하게 하기 위해, 추가적으로 코드를 첨가할 수 있도록 만든 것이 웹 응용 프로그램이다. 그 예로는 cgi, php, jsp, java, python 등이 있다. 많은 수의 언어와 다수의 프로그램들이 빠른 속도로 개발됨에 따라 많은 수의 보안 문제점들이 발생하였고 실제로 대단히 많은 서버들이 침입의 대상이 되었다. 웹 응용 프로그램의 보안에 많은 문제점이 발생한 이유는 첫번째, 기존의 서버 응용 프로그램들에 비하여 웹 응용 프로그램은 휠씬 많은 수가 아주 빠르게 개발되었다는 점이다. 두 번째는 웹 응용 프로그램에서 발생한 새로운 종류의 보안 위험성을 들 수 있다. 기존의 서버 응용 프로그램에서 발생하는 위험성들은 서버프로그램의 버그를 이용한 것이었고, 이들은 외부 입력의 내용보다는 그 크기 등의 간단히 검사 가능한 특징에 의존하는 경우가 많았다. 하지만, 웹 응용 프로그램이 외부 입력의 내용을 코드의 일부로 사용하는 경우가 많음으로 인해서, 웹 응용 프로그램에서는 간단히 검사하기 어려운 특징인 입력의 내용에 의존하는 위험성들이 많이 발생한다. 본 논문에서는 이러한 새로운 방식의 위험성을 소스코드를 이용해서 어떻게 자동적으로 검사할 수 있을 지에 관해서 새로운 아이디어를 제시한다. 이 아이디어는 현재 구현 중에 있으며, 초기 실험 결과 기존의 검사 프로그램들이 찾아내지 못하는 취약점들을 찾아낼 수 있음이 확인되었다.

• International Journal of Computer Science & Network Security
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• v.21 no.8
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• pp.137-140
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• 2021

The article is devoted to the study of the issue of liability for the dissemination of inaccurate information on the Internet. The article emphasizes that now the public opinion of socially active segments of the population is mainly formed on the basis of not critical but subjective ("consumer") analysis of the received information. The modern realities show that the main source of its origin is the Internet: electronic media and, above all, the relevant social networks. The problem of dissemination by the mass media of inaccurate information obtained via the Internet is solved; it is seen in bringing the laws of Ukraine, which regulate public relations regarding the dissemination of information, into compliance with the Civil Code of Ukraine. The issues of development and implementation of new legislative acts aimed at regulating the status of subjects of informational relations on the Internet and establishing the grounds for their liability are also investigated.

• KEPCO Journal on Electric Power and Energy
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• v.5 no.2
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• pp.103-111
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• 2019

The combined cycle plant is an integration of gas turbine and steam turbine, combining the advantages of both cycles. It recovers the heat energy from gas turbine exhaust to use it to generate steam. The heat recovery steam generator plays a crucial role in combined cycle plants, providing the link between the gas turbine and the steam turbine. Simulation of the performance of the HRSG is required to study its effect on the entire cycle and system. Computational fluid dynamics has potential to become a useful to validate the performance of the HRSG. In this study a solver has been implemented in the open source code, OpenFOAM, for combustion simulation in the heat recovery steam generator. The solver is based on the steady laminar flamelet model to simulate detailed chemical reaction mechanism. Thereafter, the solver is used for simulation of HRSG system. Three cases with varying fuel injections and gas turbine exhaust gas flow rates were simulated and the results were compared with measurements at the system outlet. Predicted temperature and emissions and those from measurements showed the same trend and in quantitative agreement.