• 전기학회논문지P
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• 제63권4호
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• pp.322-326
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• 2014

Recently, the LOE(loss of excitation) incidents are occurred in domestic synchronous generator frequently, the synchronous generator protection system has been much attention for the LOE protection of the incidents that threats synchronous generators and power systems. This paper was showed the characteristics and practices of distance relay that widely used LOE protection relaying in generator. Firstly, the operating characteristics and the impedance locus for LOE of the generator protection were introduced. Even if the conventional simulation program is used for modeling, but it is difficult to implement a LOE modeling and simulation of synchronous generator. So, the LOE relay operation data collected from thermal power plant and nuclear power plant in real fields were analyzed. By reviewing the applications of GE Mho relays, the reliability of LOE for synchronous generator protection in domestic were improved.

• 전기학회논문지P
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• 제63권3호
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• pp.149-156
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• 2014

Generator of hydroelectric generating unit is to be protected by the digital protection IED. Now, any IED of large capacity for hydro power plant was not developed by domestic technology. This is because it is required for the generator of the high reliability technology and considered as due to the sale of the market of IED device is small. However, the protection IED must be develop by domestic technology to meet the advanced needs of the construction and replacement of electrical equipment in accordance with the new power plant development. In this paper, a digital algorithms for protection IED of large size of hydroelectric generating unit were designed. The algorithms consist of the stator protection, anti-motoring, overexcitation and loss of excitation. The performance of the algorithms were evaluated by using the simulation data collected from the PSCAD/EMTDC software. From test results, it can be seen that the developed algorithms were not maloperation.

• 지식경영연구
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• 제18권3호
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• pp.63-80
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• 2017

Big Data environment is established by accumulating vast amounts of data as users continuously share and provide personal information in online environment. Accordingly, the more data is accumulated in online environment, the more data is accessible easily by third parties without users' permissions compared to the past. By utilizing strategies based on data-driven, firms recently make it possible to predict customers' preferences and consuming propensity relatively exactly. This Big Data environment, on the other hand, establishes 'Dataveillance' which means anybody can watch or control users' behaviors by using data itself which is stored online. Main objective of this study is to identify the relationship between Dataveillance and users' online privacy protection behaviors. To achieve it, we first investigate perceived online service efficiency; loss of control on privacy; offline surveillance; necessity of regulation influences on users' perceived threats which is generated by Dataveillance.

• 전기학회논문지P
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• 제63권2호
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• pp.74-80
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• 2014

Generator protection device has to detects an internal fault conditions in generator and abnormal operating conditions must be due to the hazards. Loss of excitation may cause generator itself failure as well as serious operating problem in power system, and then requires an appropriate response of generator protection device. Details modeling of generator control system and analysis of transient states in generator are important for optimal operation in power plants. In addition, the fault simulation data are also used for testing the characteristics of IED. In this paper, the hydro generator control system using PSCAD/EMTDC, visual simulation for power systems, was modeled. The generator control system which is composed of generator, turbine, exciter, governor was implemented. The parameters of generator control system model were obtained from field power plant. Loss of excitation simulations were performed while varying the fixed load. Several signals analysis were also performed so as to analyze transients phenomena.

• Journal of Advanced Marine Engineering and Technology
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• 제20권2호
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• pp.92-92
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• 1996

Recently, with the rapid development in the oceanic systems such as the oceanic structures and vessel, there occurs much interest in the impingement erosion-corrosion. In this paper, Cu-metal was tested by using of erosion apparatus with water-jet type and was investigated under the behaviour of impingement erosion-corrosion according to various environmental conditions, and the properties of Cu-metal were evaluated through the measurement by weight loss, weight loss rate, protective efficiency. The results were compared with those obtained using Cu-metal applied to cathodic protection and Cu-alloys added to Zn or Al-metal. As a basis of those results, the best protective efficiencies could be taken as using cathodic protection method and Cu-alloy with Al & Zn material addings, and will be suggested as the fundamental data of the anti-impingement erosion-corrosion on Cu-metal of impeller material for oceanic centrifugal pump.

• Journal of Advanced Marine Engineering and Technology
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• 제20권2호
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• pp.24-31
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• 1996

Recently, with the rapid development in the oceanic systems such as the oceanic structures and vessel, there occurs much interest in the impingement erosion-corrosion. In this paper, Cu-metal was tested by using of erosion apparatus with water-jet type and was investigated under the behaviour of impingement erosion-corrosion according to various environmental conditions, and the properties of Cu-metal were evaluated through the measurement by weight loss, weight loss rate, protective efficiency. The results were compared with those obtained using Cu-metal applied to cathodic protection and Cu-alloys added to Zn or Al-metal. As a basis of those results, the best protective efficiencies could be taken as using cathodic protection method and Cu-alloy with Al & Zn material addings, and will be suggested as the fundamental data of the anti-impingement erosion-corrosion on Cu-metal of impeller material for oceanic centrifugal pump.

• 한국정보전자통신기술학회논문지
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• 제4권3호
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• pp.217-224
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• 2011

본 논문에서는 동적 데이터베이스 환경에서 발생할 수 있는 개인 정보 노출 문제를 해결할 수 있는 동적 데이터 보호 기법(Dynamic Data Protection Technique)을 제안하였다. 본 논문에서 제안한 DDPT은 다중 속성 일반화 알고리즘을 이용해 MAG(Multi-Attribute Generalization) 규칙을 생성하고, 그 MAG 규칙에 따라 k-anonymity를 만족하는 EC(Equivalence Class)를 생성한다. 그리고 데이터 변경 시 MAG 규칙에 따라 EC를 재구성 하도록 하여, EC의 변경으로 인한 식별 노출을 방지할 수 있다. 또한, ${\ell}$-diversity를 만족하는 EC의 정보손실 정도를 측정하고, 임계치 이하의 EC를 선정해서 데이터의 정확성을 유지함으로써 개인 정보 보호를 향상시켰다.

• 한국화재소방학회논문지
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• 제16권4호
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• pp.59-64
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• 2002

버터플라이 밸브의 압력손실과 캐비테이션에 대한 유동특성 연구를 수행하였다. 밸브의 열림각에 대한 압력손실계수는 Carnot 방정식을 응용하여 수식화하였다. 캐비테이션(캐비테이션의 발단, 슈퍼 캐비테이션, 캐비테이션 손상, 초킹 캐비테이션과 같은)은 밸브의 압력손실계수로부터 예측되었다. 압력손실과 캐비테이션 예측은 밸브의 열림각에 대한 두께 비의 변화에 따라 수행하였다. 예측 데이터는 버터플라이 밸브를 개발하는데 필요한 엔지니어링 데이터로 활용하고자 한다.

• International Journal of Computer Science & Network Security
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• 제21권1호
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• pp.119-124
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• 2021

Elastic Optical Networks (EONs) allow to solve the high demand for bandwidth due to the increase in the number of internet users and the explosion of multicast applications. To support multicast applications, network operator computes a tree-shaped path, which is a set of optical channels. Generally, the demand for bandwidth on an optical channel is enormous so that, if there is a single fiber failure, it could cause a serious interruption in data transmission and a huge loss of data. To avoid serious interruption in data transmission, the tree-shaped path of a multicast connection may be protected. Several works have been proposed methods to do this. But these works may cause the duplication of some resources after recovery due to a link failure. Therefore, this duplication can lead to inefficient use of network resources. Our work consists to propose a method of protection that eliminates the link that causes duplication so that, the final backup path structure after link failure is a tree. Evaluations and analyses have shown that our method uses less backup resources than methods for protection of a multicast connection.

• 융합보안논문지
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• 제18권5_1호
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• pp.121-126
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• 2018

현대의 정보통신 기술과 네트워크 기술이 발달은 기업의 운영환경을 스마트하게 변화시켰으며, 그 가운데서 수많은 데이터들이 생성되고 저장되고 사용되고 있다. 기업경영의 에너지원이 되는 중요한 정보는 경제적인 이윤과 가치를 생성하고 또한 강력한 영향력의 근거로 활용된다. 따라서 주요정보는 그 가용성과 편의성을 확보해야 함과 동시에 기밀성과 무결성을 담보해야 하는 것이며 이것이 바로 정보보호의 기본목표가 된다고 할 수 있다. 그러나 대부분의 기업들은 중요한 내부정보가 유출되어 심각한 피해를 야기하는 사고가 증가하고 있다. 이에 본 연구에서는 내부정보유출을 방지하고 안정적인 데이터보안 및 정보보호관리 구축을 위한 DLP(Data Loss Prevention) 기술과 솔루션에 대해 살펴본다.