• Nuclear Engineering and Technology
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• 제53권5호
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• pp.1658-1663
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• 2021

Research on climate change and global warming on the power generation systems are rapidly increasing because of the Importance of the sustainable energy supply, thus the electricity supply since its growing share, in the end, uses energy supply. However, some researchers conducted this field, but many research gaps are not mentioned and filled in this field's literature since the lack of general statements and the quantitative models and formulation of the issue. In this research, an exergy-based model is implemented to model a set of six power generation technologies (combined cycle, gas turbine, nuclear plant, solar PV, and wind turbine) and use this model to simulate each technology's responses to climate change impacts. Finally, using these responses to define and calculate a formulation for the relationship between the system's energy performance in different environmental situations and a dimensionless index to quantize each power technology's reliability against the climate change impacts called the Pahlev reliability index (P-index) of the power technology. The results have shown that solar and nuclear technologies are the most, and wind turbines are the least reliable power generation technologies.

• Journal of Electrical Engineering and Technology
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• 제10권2호
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• pp.465-473
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• 2015

The increasing need to improve transient security assessment of existing or forecasted operating conditions of networks by power system operators is major concern of the power system security monitoring problem at the Energy Management Systems. This paper proposes a preventive control of transient stability with generation rescheduling based on rotor trajectory index obtained using time domain simulations. This index may help power engineers in making operational decision and to obtain a generation configuration with better transient security dispatch. The effectiveness of the proposed methodology is demonstrated on IEEE 39-bus New England system for a three phase fault at different loading conditions with single and multiple line outage cases.

• ETRI Journal
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• 제45권4호
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• pp.636-649
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• 2023

Renewable energy generation cannot be consistently predicted or controlled. Therefore, it is currently not widely used in the electricity market, which requires dependable production. In this study, reliability- and variance-based controls of energy storage strategies are proposed to utilize renewable energy as a steady contributor to the electricity market. For reliability-based control, photovoltaic (PV) generation is assumed to be registered in the power generation plan. PV generation yields a reliable output using energy storage units to compensate for PV prediction errors. We also propose a runtime state-ofcharge management method for sustainable operations. With variance-based controls, changes in rapid power generation are limited through ramp rate control. This study introduces new reliability and variance indices as indicators for evaluating these strategies. The reliability index quantifies the degree to which the actual generation realizes the plan, and the variance index quantifies the degree of power change. The two strategies are verified based on simulations and experiments. The reliability index improved by 3.1 times on average over 21 days at a real power plant.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 추계학술대회 논문집 전력기술부문
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• pp.202-204
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• 2003

This paper suggests an optimal parameter setting method by use of parametric protectability index, as the objective function. In this paper, a gradient based optimization method is used under the assumption that the initial values of a parameter is in a convex set including the optimal value, which is verified by a plenty of simulation studies. The proposed method is applied to a sample distribution network to shows its effectiveness.

• 가족자원경영과 정책
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• 제20권3호
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• pp.115-129
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• 2016

This study is about the happiness of married women from the baby boom generation. The study aims to understand the impact of the married life of such women on the happiness index and to improve the happiness of married women by improving married life. The data for this study were drawn from the National Women and Family Panel Survey (4th year data) carried out by the Korean Women's Development Institute. The subjects for the final analysis totaled 885 married women from the baby boom generation, born between 1955 and 1963. Of these, 550 were married women in a dual income family, and 335 were married women in a husband-income family. IBM SPSS Statistic 21.0 was used. The findings from this study are as follows: First, the women's happiness index was higher in cases where the women had a more positive view of their husbands, the more often they were involved in leisure activities, the better their conflict resolution whenever there was a clash of opinions, and the more satisfied they were with the division of household labor. Second, in the case of dual income families, the women's happiness index was higher where they had a positive view of their husbands, their conflicts were better resolved, and the more satisfied they were with the division of household labor. Third, in the case of married women in a husband-income family, their happiness index rose the more positively they perceived their husbands, the more often they were involved in leisure activities together, and the more satisfied they were with the division of household labor.

• 한국정보통신학회논문지
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• 제23권5호
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• pp.508-515
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• 2019

소프트웨어 관련 R&D 사업의 결과의 성공여부를 판단하는 기준으로 다양한 정량지표를 많이 사용하고 있으나, 어떠한 정량지표를 선정하는 것이 적절한지에 대한 판단은 다소 어려운 부분이 있다. 본 논문에서는 소프트웨어 개발의 정량적 평가지표 선정에 기준을 제공하기 위해 소프트웨어 품질 수준의 표준으로 활용되고 있는 ISO/IEC25023를 활용하여 소프트웨어 제품 개발의 정량적 평가지표 생성프로세스를 제안한다. 제안 프로세스는 2단계로 구성되어 있다. 첫 번째 단계에서는 ISO/IEC25023 표준규격의 품질특성과 부특성을 도출하고, 두 번째 단계에서는 1단계 결과인 품질특성과 부특성에 부합하는 평가지표 가이드를 도출한다. 제안하는 정량적 평가지표 생성 프로세스는 소프트웨어 개발 프로젝트의 특성에 맞는 정량적 평가지표 선정에 도움이 될 것으로 기대한다.

• 한국기후변화학회지
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• 제8권4호
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• pp.357-367
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• 2017

Electricity generation in Korea mainly depends on thermal power and nuclear power. Especially the coal power has led to the increase in $CO_2$ emissions. This paper intends to analyze the current status of $CO_2$ emissions from electricity generation in Korea during the period 1990~2016, and apply the logarithmic mean Divisia index (LMDI) technique to find the nature of the factors influencing the changes in $CO_2$ emissions. The main results as follows: first, $CO_2$ emission from electricity generation has increased by $165.9MtCO_2$ during the period of analysis. Coal products is the main fuel type for thermal power generation, which accounts about 73% $CO_2$ emissions from electricity generation. Secondly, the increase of real GDP is the most important contributor to increase $CO_2$ emissions from electricity generation. The carbon intensity and the electricity intensity also affected the increase in $CO_2$ emission, but the energy intensity effect and the dependency of thermal power effect play the dominant role in decreasing $CO_2$ emissions.

• 설비공학논문집
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• 제26권3호
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• pp.108-114
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• 2014

On a large scale of data center, heat generation rates from sever computers occupy almost the entire cooling load of the building, and it is gradually increasing. The efficiency of air distribution system in data centers can be affected by heat generation rates of server computers. In this study, the distributions of airflow and temperature in a data center have been investigated by CFD simulations under various conditions of heat generation rates for server computers. From the results, air around the cold aisle which has high temperature flows tremendously into the cold aisle according to the increase of heat generation rates for server computers and the air temperature in the cold aisle becomes higher. The SHI (supply heat index) and RHI (return temperature index) show almost similar values to the cases study because the air inflow rates to server computers increase with the heat generation rates of server computers.

• Journal of Welding and Joining
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• 제16권3호
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• pp.95-101
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• 1998

Waveforms of $CO_2$ gas shielded arc welding in short circuit transfer mode was studied with the waveform analysis program, which can calculate various waveform factors such as number of short circuit event, mean and standard deviation of short circuit time and arc time. The calculated values of these factors were correlated independently or in combination with the spatter generation rate to figure out the most reliable index for evaluating spatter generation and further for arc stability. As a result this study, it was confirmed that the spatter generation tends to decrease with the increase of short circuit frequency. Further to this, it was also found that as the short circuit frequency increases the short circuit event becomes more uniform resulting in the decrease of standard deviations ($\sigma$values) of short circuit time and arc time. This result demonstrated that these factors are strongly correlated with each other and thus any one of these factors can be used for the evaluation index. In the discussion, however, short circuit frequency was proposed for the most practical index in evaluating the arc stability of short circuit transfer mode since it is the one which could be monitored in-process condition without any complex caculation process.

• 한국융합학회논문지
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• 제10권4호
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• pp.33-38
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• 2019

최근 다양한 LBS(location-based service) 서비스를 지원하기 위해 실제 공간 네트워크를 고려한 연구가 활발하게 진행 중이다. 이를 위해, 도로 네트워크에서 데이터 처리를 위한 실험 데이터가 다수 존재한다. 그러나 이러한 이동 객체의 궤적을 처리하기 위한 데이터는 이용하기에 적합하지 않다. 따라서 본 논문에서는 도로 네트워크 환경에서 궤적 데이터를 처리할 수 있는 색인 구조와 궤적 데이터 생성 알고리즘을 제안한다. 또한, 제안하는 구조와 알고리즘의 우수성을 입증하기 위해, 샌프란시스코 맵으로부터 만들어진 데이터를 이용하여 제안하는 알고리즘을 통해 에지 기반의 궤적 데이터를 생성됨을 보인다.