• Nuclear Engineering and Technology
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• 제53권4호
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• pp.1345-1356
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• 2021

Damage to nuclear power plants causes human casualties and environmental disasters. There are electrical facilities that control safety-related devices in nuclear power plants, and seismic performance is required for them. The 2016 Gyeongju earthquake had many high-frequency components. Therefore, there is a high possibility that an earthquake involving many high frequency components will occur in South Korea. As such, it is necessary to examine the safety of nuclear power plants against an earthquake with many high-frequency components. In this study, the shaking table test of electrical facilities was conducted against the design earthquake for nuclear power plants with a large low-frequency components and an earthquake with a large high-frequency components. The response characteristics of the earthquake with a large high-frequency components were identified by deriving the amplification factors of the response through the shaking table test. In addition, safety of electrical facility against the two aforementioned types of earthquakes with different seismic characteristics was confirmed through limit-state seismic tests. The electrical facility that was performed to the shaking table test in this study was a motor control center (MCC).

• 분석과 대안
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• 제1권2호
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• pp.2-12
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• 2017

Research on democratic transitions has relatively ignored the question of why some countries experience a regressive form of political pacts, while others do not. This paper develops a simple game-theoretic model to explain the phenomenon of collusive pacts in the process of democratization. Trasformismo is a term that refers to a system of political exchange based on informal clientelistic politics. The existing studies of the politics of trasformismo have emphasized the timing of industrialization and the tradition of strong state as conditions of the politics of trasformismo. However, not every late industrializers and not every strong states experienced some variants of collusive political pacts in their trajectories of democratization. In this paper, I contend that the politics of trasformismo is rather a generalizable pattern of political elites' behavior under particular circumstances. By developing a simple game theoretic model, this paper suggests the conditions under which political actors are likely to collude to a regressive form of political pacts. The model shows that the likelihood of collusion to a regressive form of political pacts is a function of a set of parameters. First, a higher level of incumbency advantage in electoral competition is likely to be associated with a higher probability of collusive political pacts. Second, a higher degree of the monopoly of political representation of political parties without a close link with a variety of societal forces is likely to induce collusive behavior among politicians. Third, the ruling party leader's expectations about the likelihood of a safe extrication are related to collusive political pacts. This paper then engages in a case study of the 1990 three-party merger in South Korea. The 1990 Korean case is interesting in that the ruling party created a new party after having merged with two opposition parties. This case can be considered a result of political maneuver in a context of democratization. The case study suggests the empirical relevance of the game-theoretic model. As the game of trasformismo and the case study of the 1990 three-party merger in South Korea have shown, the collusive political pact was neither determined by a certain stage of economic development nor by a particular cultural systems. Rather, it was a product of the art of trasformismo based on party leaders' rational calculations of the expected likelihood of taking governing power.

• 산업경영시스템학회지
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• 제12권20호
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• pp.55-61
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• 1989

The main contribution this research is the development of methodology which is capable of solving problems associated with the capacity expansion and operating schedule of energy industries. The principal concern of such industries is the proper allocation of primary energy which are required for the production of sufficient supply of electricity and petroleum products for the Korea`s energy needs. Nonlinear programming models are developed for power generation expansion planning and for the oil refinery industry. In order to deal with uncertainties about future demands for final energy, chance-constrained programming is used to formulate appropriate constraints. The methodology of the model can be used to evaluate Korean energy and expansion planning in the energy industry, especially the electric power generation industry and the refinery industry.

• 시스템엔지니어링학술지
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• 제16권2호
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• pp.1-15
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• 2020

Nuclear power plants in South Korea are operated to cover the baseload demand. Hence they are operated at 100% rated power and do not deploy power tracking control except for startup, shutdown, or during transients. However, as the contribution of renewable energy in the energy mix increases, load follow operation may be needed to cover the imbalance between consumption and production due to the intermittent nature of electricity produced from the conversion of wind or solar energy. Load follow operation may be quite challenging since the operators need to control the axial power distribution and core reactivity while simultaneously conducting the power maneuvering. In this paper, a systems engineering approach for multi-physics load follow simulation of APR1400 is performed. RELAP5/SCDAPSIM/MOD3.4/3DKIN multi-physics package is selected to simulate the Korean Advanced Power Reactor, APR1400, under load follow operation to reflect the impact of feedback signals on the system safety parameters. Furthermore, the systems engineering approach is adopted to identify the requirements, functions, and physical architecture to provide a set of verification and validation activities that guide this project development by linking each requirement to a validation or verification test with predefined success criteria.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2007년도 학술발표회 논문집
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• pp.58-66
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• 2007

This paper introduces the new generic dynamic neuro-fuzzy local modeling system (DNFLMS) that is based on a dynamic Takagi-Sugeno (TS) type fuzzy inference system for complex dynamic hydrological modeling tasks. The proposed DNFLMS applies a local generalization principle and an one-pass training procedure by using the evolving clustering method to create and update fuzzy local models dynamically and the extended Kalman filtering learning algorithm to optimize the parameters of the consequence part of fuzzy local models. The proposed DNFLMS is applied to develop the inference model to forecast the flow of Waikoropupu Springs, located in the Takaka Valley, South Island, New Zealand, and the influence of the operation of the 32 Megawatts Cobb hydropower station on springs flow. It is demonstrated that the proposed DNFLMS is superior in terms of model accuracy, model complexity, and computational efficiency when compared with a multi-layer perceptron trained with the back propagation learning algorithm and well-known adaptive neural-fuzzy inference system, both of which adopt global generalization.

• 한국환경농학회지
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• 제41권4호
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• pp.252-260
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• 2022

BACKGROUND: The number of biomass power plants is increasing around the world and the amount of wastes from power plants is expected to increase. But the bottom ash (BA) is not recycled and has been dumped in landfill. This study was conducted to find out functional groups of BA and adsorption rate of heavy metals on BA. METHODS AND RESULTS: The BA was dried in oven at 105℃ for 24 hours, and characterized by analyzing the chemistry, functional group, and surface area. The adsorption rates of heavy metals on BA were evaluated by different concentration, time, and pH. As a result, the adsorption amount of the heavy metals was high in the order of Zn> Cu> Cd> Ni and the removal rates of Zn, Cu, Cd, and Ni by BA was 49.75, 30.20, 32.46, and 36.10%, respectively. Also, the maximum adsorption capacity of BA was different by the heavy metal in the environmental conditions, and it was suggested that the isotherms for Zn, Ni, Cd, and Cu were adequate to Langmuir model. CONCLUSION(S): It is suggested that it would be effective to remove heavy metals in aqueous solution by using BA from biomass power plants in South Korea.

• Journal of Advanced Research in Ocean Engineering
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• 제3권4호
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• pp.184-192
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• 2017

The Korea Offshore Wind Power (KWOP) cooperation is planning to construct offshore wind energy farms with an overall rated power of 2.5 GW along the southwestern coast by 2019. Hitherto, various structural types of support structures for offshore wind turbines have been being proposed, but these structures have lacked economic analysis studies. Therefore, their economical superiority to existing types has been difficult to guarantee. An offshore structure with economic efficiency will have a minimum amount of mobilizing equipment and short offshore construction period because of the application of rapid installation methods. Thus, the development of a new support structure with economic efficiency is generally considered to be necessary. Accordingly, this paper proposes a newly developed and more economical jacket type for the offshore support structure. This study confirmed its structural safety and performance by conducting a structural analysis and eigenvalue analysis. The manufacturing and installation costs were then estimated. As a result, the new jacket type of offshore support structure proposed in this study significantly reduced the manufacturing and installation costs. Therefore, it is expected that the proposed jacket will contribute to reducing construction expenses for new wind power farms and invigorating wind power farm businesses.

• Journal of Electrical Engineering and Technology
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• 제9권4호
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• pp.1163-1170
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• 2014

Due to global environmental regulations and policies with rapid advancement of renewable energy technologies, the development type of renewable energy sources (RES) in power systems is expanding from small-scale distributed generation to large-scale grid-connected systems. In the near future, it is expected that RES achieves grid parity which means the equilibrium point where the power cost of RES is equal to the power costs of conventional generators. However, although RES would achieve the grid parity, the cost related with development of large-scale RES is still a big burden. Furthermore, it is hard to determine a suitable capacity of RES because of their output characteristics affected by locations and weather effects. Therefore, to determine an optimal capacity for RES becomes an important decision-making problem. This study proposes a method for determining an optimal installed capacity of RES from the business viewpoint of an independent power plant (IPP). In order to verify the proposed method, we have performed case studies on real power system in Incheon and Shiheung areas, South Korea.

• 한국IT서비스학회지
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• 제15권1호
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• pp.67-79
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• 2016

This study aims to present the necessary elements that should be part of South Korea's National Defense Strategy against the recent North Korean cyber-attacks. The elements proposed in this study also reflect the recent trend of cyber-attack incidents that are happening in the Unites States and other countries and have been classified into the three levels of cyber incidents: cyberwarfare, cyberterrorism and cybercrime. As such, the elements proposed are presented in accordance with this classification system. In order to properly take into account the recent trend of cyber-attacks perpetrated by North Korea, this paper analyzed the characteristics of recent North Korean cyber-attacks as well as the countermeasures and responses of South Korea. Moreover, by making use of case studies of cyber-attack incidents by foreign nations that threaten national security, the response measures at a national level can be deduced and applied as in this study. Thus, the authors of this study hope that the newly proposed elements here within will help to strengthen the level of Korea's cyber security against foreign attacks, specifically that of North Korea such as the KHNP hacking incidents and so on. It is hoped that further damage such as leakage of confidential information, invasion of privacy and physical intimidation can be mitigated.

• 전기학회논문지
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• 제63권6호
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• pp.758-763
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• 2014

These days, the advantages of DC power system are consistently stand out in korea that was a small power loss and high stability. Needs of DC power transmission technology is focused In the midst of a smart grid and environment friendly generation technology boom that is needed for next generation technology. Researches and businesses for HVDC(High Voltage Direct Current) system has been began. But, Needs of HVDC equipment and system commissioning technology are not on the rise until now. In particular, South Korea's HVDC technology is after the foot runner of advanced country and company. In addition, There is no experience for equipment verification and commissioning technology. And Experts of HVDC are rare. Who has been fully understood hardware and system as a whole, and identified all the equipment's characteristic. Recently, Academia and industry are recognized a needs of HVDC technology. But it does not received a recognition of technical value. In this paper, introduce issues when we apply the IEEE's verification method for HVDC system, especially DC current measurement system, DC CT(Direct Current Transformer), among the HVDC equipments. And Proposes remedial methods on the issue in order to recognize the necessity that was HVDC equipments's verification and commissioning technology research should be focused on.