• Journal of Electrical Engineering and Technology
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• v.12 no.6
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• pp.2196-2207
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• 2017

This paper presents a two-stage market auction model in a pool-based electricity market, which explicitly takes into account the system network security. The security network-constrained market auction model considers the use of corrective control to yield economically efficient actions in the post-contingency state, while ensuring a certain security level. Under this framework, the proposed model shows not only for quantifying the correlation between secure system operation and efficient market operation, but also for providing transparent information on the pricing system security for market participants. The two-stage market auction procedure is formulated using Benders decomposition (BD). In the first stage, the market participants bid in the market for maximizing their profit, and the independent system operator (ISO) clears the market based on social welfare maximization. System network constraints incorporating post-contingency control actions are described in the second stage of the market auction procedure. The market solutions, along with the BD, yield nodal spot prices (NSPs) and nodal congestion prices (NCPs) as byproducts of the proposed two-stage market auction model. Two benchmark systems are used to test and demonstrate the effectiveness of the proposed model.

• Journal of Electrical Engineering and Technology
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• v.12 no.4
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• pp.1397-1405
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• 2017

As the introduction of wind power is steadily increasing, negative effects of wind power become more important. To operate a power system more reliable, the system operator needs to recognize the maximum required capacity of available generators for a certain period. For recognizing the maximum capacity, this paper proposes a methodology to determine an optimal reserve requirement considering wind power, for the certain period in the mid-term perspective. As wind speed is predicted earlier, the difference of the forecasted and the actual wind speed becomes greater. All possible forecast errors should be considered in determining optimal reserve, and they are represented explicitly by the proposed matrix form in this paper. In addition, impacts of the generator failure are also analyzed using the matrix form. Through three main stages which are the scheduling, contingency and evaluation stages, costs associated with power generation, reserve procurement and the usage, and the reliability cost are calculated. The optimal reserve requirement is determined so as to minimize the sum of these costs based on the cost/reliability analysis. In case study, it is performed to analyze the impact of wind power penetration on the reserve requirement, and how major factors affect it.

• Communications for Statistical Applications and Methods
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• v.19 no.3
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• pp.495-500
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• 2012

We consider a Bayesian test of independence in a two-way contingency table that has some zero cells. To do this, we take a three-stage hierarchical Bayesian model under each hypothesis. For prior, we use Dirichlet density to model the marginal cell and each cell probabilities. Our method does not require complicated computation such as a Metropolis-Hastings algorithm to draw samples from each posterior density of parameters. We draw samples using a Gibbs sampler with a grid method. For complicated posterior formulas, we apply the Monte-Carlo integration and the sampling important resampling algorithm. We compare the values of the Bayes factor with the results of a chi-square test and the likelihood ratio test.

• Communications for Statistical Applications and Methods
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• v.27 no.1
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• pp.15-35
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• 2020

In research on behavioral studies, significant attention has been paid to the stage-sequential process for multiple latent class variables. We now explore the stage-sequential process of multiple latent class variables using the multivariate latent class profile analysis (MLCPA). A latent profile variable, representing the stage-sequential process in MLCPA, is formed by a set of repeatedly measured categorical response variables. This paper proposes the extended MLCPA in order to explain an association between the latent profile variable and the latent group variable as a form of a two-dimensional contingency table. We applied the extended MLCPA to the National Longitudinal Survey on Youth 1997 (NLSY97) data to investigate the association between of developmental progression of depression and substance use behaviors among adolescents who experienced Authoritarian parental styles in their youth.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.50 no.5
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• pp.225-233
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• 2001

SIME(SIngle Machine Equivalent) method has been recognized as a useful tool to determine transient stability of power systems. In this paper, SIME method is used to develop the KEPCO transient stability assessment (TSA) tool. A new screening algorithm that can be implemented in SIME method is proposed. The salient feature of the proposed screening algorithm is as follows. First, critical generators are identified by a new index in the early stage of the time domain simulation. Thus, computational time required to find OMIB(One Machine Infinite Bus) can be reduced significantly. Second, clustering critical machines can be performed even in very stable cases. It enables to be avoid extra calculation of time trajectory that is needed in SIME for classifying the stable cases. Finally, using power-angle trajectory and subdividing contingency classification have improved the screening capability. This algorithm is applied to the fast TSA of the KEPCO system.

• Journal of KIEE
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• v.11 no.1
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• pp.55-61
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• 2001

SIME(Single Machine Equivalent) method has been recognized as a useful tool to determine transient stability of power system. In this paper, SIME method is used to develop the KEPCO transient stability assessment (TSA) tool. A new screening algorithm that can be generators are identified by a new index in the early stage of the time domain simulation. Thus, computational time require to find OMIB(One Machine Infinite Bus) can be reduced significantly. Second, clustering critical machines can be performed even in very stable cases. It enables to be avoid extra calculation of time trajectory that is needed in SIME for classifying the stable cases. This algorithm is applied to the fast TSA of the KEPCO system in the year of 2010.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.4
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• pp.1627-1631
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• 2015

Background: Stage at diagnosis is one of the most important prognostic factors of breast cancer survival. Because in the breast cancer case this may vary with socioeconomic characteristics, this study was performed to recognize the relationship between demographic and socioeconomic factors with stage at diagnosis in Iran. Materials and Methods: This cross-sectional, descriptive study conducted on 526 patients suffering from breast cancer and registered in Cancer Research Center of Shahid Beheshti University of Medical Sciences from 2008 to 2013. A reliable and valid questionnaire about family levels of socioeconomic status filled in by interviewing the patients via phone. For analyzing the data, Multinomial logistic regression, Kendal tau-b correlation coefficient and Contingency Coefficient tests were executed by SPSS22. Economic status, educational attainment of patient and household head and/or a combination of these were considered as parameters for socioeconomic status. First, the relationship between stage at diagnosis and demographic and socioeconomic status was assessed in univariate analysis then these relationships assessed in two different models of multinomial logistic regression. Results: The mean age of the patients was 48.3 (SD=11.4). According to the results of this study, there were significant relationships between stage at diagnosis of breast cancer with patient education (p=0.011), living place (p=0.044) and combined socioeconomic status (p=0.024). These relationships persisted in multiple multinomial logistic regressions. Other variables, however, had no significant correlation. Conclusions: Patient education, combined socioeconomic status and living place are important variables in stage at diagnosis of breast cancer in Iranian women. Interventions have to be applied with the aim of raising women's accessibility to diagnostic and medical facilities and also awareness in order to reducing delay in referring. In addition, covering breast cancer screening services by insurance is recommended.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2006.11a
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• pp.295-300
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• 2006

In this research, risk factors which can raise project cost are identified in the initial stage and picked out through the decision maker's baseline. And also this probable risks are implemented to the project cash flow to estimate the contingency and to build a risk management system in the level of project. The risks that affect the projects profits were classified in two categories in the risk checklist. Firstly, financial risks derived from the external economic conditions for example exchange rate, escalation, interest rates etc. are analyzed through the stochastic methods, Monte-Carlo Simulation. Secondly, the project individual risks which are come from the project characteristics, for example country risk, clime, owner etc., are evaluated using the utility curve of the decision maker. Finally these risk analysis methods are used to forecast the actual project cash flow and final profit.

• Journal of National Security and Military Science
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• s.8
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• pp.169-238
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• 2010

The year 2010 is the 60th anniversary commemorating the Korean War. China intervened in the Korean War with the logics such as "To Resist the U.S.'s Aggression and Aid North Korea," "Save Endangered Home & defend Nation," and "If the Lips Are Gone, the Teeth Will Be Exposed to the Cold or If One of Them Falls, the Other is in Danger." However, China had a deep and long connection with North Korea through 1st Chinese Civil War, war against Japan imperialism, and 2nd Chinese Civil War. China has consulted with Kim Il-sung on his invasion of South Korea at the initial stage of development and played a casting vote role in the execution of the invasion plan. During the Korean War, the PLA supported the North Korea's regime by its action, and made the Korea Peninsula divide into two semi-permanently. Even after the war, China continues to maintain relations with North Korea by helping North Korea build the Kim Il-sung's Kingdom. Currently, whenever any issue related to North Korea rises in the international society, China definitely gets involved in those issues and exercises its power. Conditionally 'either armed aggression or, and wartime' in North Korea, China would follow the "Clause of Military Auto Intervention." In addition, China is very likely to establish refugee camps for North Koreans in the Northeastern-Three-Province and to provide rear bases or guerrilla camps for pro-Chinese sects. Furthermore, voluntarily playing a role as spokesman of North Korean Regime in the international society, China will exercise enormous influence on the reunification of the Korean Peninsula.

• Journal of the Korean Society of Clothing and Textiles
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• v.22 no.1
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• pp.49-60
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• 1998

This study found through that Fortuny's art world with design aesthetics was devided into historicism, purism, exoticism and mysticism of color. \circled1 Fortuny's aesthetic observation dazzled at that time and he apply well-grounded opinion in historicism of his all creation and then accomplish on the whole mysticism of art and technique dwelled creativity, \circled2 Fortuny's Delphos gown realized new creation of beauty intact by that the simplicity and contingency was inquired into the art at that time. He revived that aesthetic was included in the drapery of ancient Greece, so indirectly express outline of the human body and realized pure image used a natural curved line of the human body. \circled3 Fortuny's creations included a exotic special quality. His clothes expected so many characteristics of 20C fashion and exotic, visionary fashion revolution in addition influenced on stage costume. ㉧ Fortune created new color specially "Tempera" and expressed mysticism of color that found a harmonious color character and texture through the ancient techniques included experimental mind of a multilateral try.teral try.