• Journal of Electrical Engineering and Technology
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• v.8 no.4
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• pp.694-703
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• 2013

In electric power system, the line stability indices adopted in most of the instances laid stress on variation of reactive power than real power variation of the transmission line. In this paper, a proposal is made with the formulation of a New Voltage Stability Index (NVSI) which originates from the equation of a two bus network, neglecting the resistance of transmission line, resulting in appreciable variations in both real and reactive loading. The efficacy of the index and fuzzy based load flow are validated with IEEE 30 bus and Tamil Nadu Electricity Board (TNEB) 69 bus system, a practical system in India. The results could prove that the identification of weak bus and critical line in both systems is effectively done. The weak area of the practical system and the contingency ranking with overloading either line or generator outages are found by conducting contingency analysis using NVSI.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.335-337
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• 2005

The purpose of this work is to explain techniques achieved while developing a transient stability program which is suitable to Korean power system, and to add a module for contingency screening. It concentrates on the development of Contingency Screening Module. In this thesis, a fast contingency screening algorithm SIME(Single Machin Equivalent), which is one of the Hybrid methods for the transient stability assessment is used to develop the contingency screening module. The proposed module is applied to a KEPCO system, and simulation results obtained from the program are compared to those of commercial programs.

• Journal of the Korean Society of Costume
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• v.59 no.5
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• pp.41-52
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• 2009

In contemporary art, soft materials are used in various forms and ways as a medium expressing contingency beyond a simple nature of materials. In the late 1960's, the appearance of soft sculpture as a refusal of the stereotyped 'Erection' characteristic of traditional sculpture served as an opportunity for more attention to soft materials. Fashion is the reflection of age, and the mirror of society, culture and arts. In other words, soft sculpture and fashion are artistic behaviors in the same context, which have neither been fixed nor erected. This study finds its significance in analyzing correlation between soft sculpture and fashion, and the importance of contingency as artistic expression means in this age when boundaries between genres are obscure, and artistic values are given to fashion. By doing so, it aims to present the direction toward which fashion should face in the future, establishing a new aesthetic consciousness with which more creative and various expressions are available in fashion as well. This study presented as its theoretical background the concept of soft sculpture affected by Marcel Duchamp among representative examples of the contingency that started to appear in art starting in the early 20th century. It also analyzed the soft sculpture appeared in 1960s and the expression methods and features of contingency appeared in fashion after late 1990s through a new approach of piling up, hanging up, and tying, three categories classified by Maurice $Fr{\acute{e}}churet$. Common features of the contingency expressed in soft sculpture and fashion were derived in the analysis, which are intensive effects of energy, values given to physical properties themselves, and esthetics of anti-form.

• Journal of the Korean Statistical Society
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• v.28 no.3
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• pp.347-358
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• 1999

Correspondence analysis is an exploratory method for two-way contingency tables intended to display the association pattern between row and column categories. It has been developed for several decades mainly in France and Japan and, nowadays, is popular worldwide. For the special case, however, that the column consists of ordered categories, correspondence analysis may yield ackward result so that it cannot be fully accommodated. That's because the row and column categories are assumed to be nominal in the ordinary correspondence analysis. The aim of this study is to develop the correspondence analysis for two-way contingency tables with ordered column categories. It is based on two specific algorithms,

• Communications for Statistical Applications and Methods
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• v.21 no.4
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• pp.275-284
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• 2014

Matched pairs are twice continuously measured data with the same categories. They can be represented as the square contingency tables. We can also consider symmetry and marginal homogeneity. Moreover, we can infer the matched pairs models; the symmetry model, the quasi-symmetry model, and the ordinal quasi-symmetry model. These inferences are involved in assumptions for special distributions. In this study, we visualize matched pairs models using modified correspondence analysis. Modified correspondence analysis can be used when square contingency tables are given; consequently, it is involved in the square and asymmetric correspondence matrix. This technique does not need assumptions for special distributions and is more helpful than the correspondence analysis to visualize matched pairs models.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2003.10a
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• pp.297-302
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• 2003

This study was carried out to check the contingency planning methods under the analysis of oil spill potential and make a guide line to apply the results to the port of Busan. The expected spilled oil drift patterns are considered with the most probable scenarios under the base of the oil spill potential. The results obtained from this study are as follows: (1) Analysis method of oil spill potent was proposed and the applicability was proved by the application example to the port of Busan to make the contingency plan. (2) Responsible oil spill contingency planning methods / flow are suggested considered environmental factors and the oil spill potential. (3) The coastal waters of Busan was consist of rocky flat, man-made solid shore and beach shore. Marine traffic have high density of oil tanker and cargo ship. Also, oil tanker ship are examined in the small ships to be less than 3000t to supply oil to the ship moored / anchored as well as the large amount of oil tank / basin are located along the coast of Busan port. These systems are introduced to make in put data to the analysis of oil spill potential. (4) According to the analysis of historical records of oil spill accident in Busan, the frequency of accidents by cargo ship rank highest and 45% of accidents is caused by carelessness. about 65% of total accidents shows a small spill accident of less than $10k{\ell}$.

• KIEE International Transactions on Power Engineering
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• v.3A no.3
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• pp.161-167
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• 2003

This paper presents a study performed to investigate the steady-state operational strategies of UPFCs in the Jeollanam-Do system in Korea. The objective of the study was to determine the UPFC operating points under normal and contingency conditions. The study consists of developing load flow models to simulate different load levels with and without UPFCs in the system, assessing the effectiveness of UPFCs by contingency analysis, and introducing optimal corrective actions for removing voltage problems caused by contingencies. The paper describes analytical tools, models and approach. It also includes analysis and discussion of the study results. The paper contributes to the area of transmission operational studies with FACTS applications.

• Journal of Electrical Engineering and Technology
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• v.4 no.3
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• pp.353-359
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• 2009

This paper proposes a novel technique for calculating the security costs that properly includes ramping constraints in the operation of a deregulated power system. The ramping process is modeled by a piecewise linear function with certain assumptions. During this process, a ramping cost is incurred if the permissible limits are exceeded. The optimal production costs of the power producers are calculated with the ramping cost included, considering a time horizon with N-1 contingency cases using contingency constrained optimal power flow (CCOPF), which is solved by the primal-dual interior point method (PDIPM). A contingency analysis is also performed taking into account the severity index of transmission line outages and its sensitivity analysis. The results from an illustrative case study based on the IEEE 30-bus system are analyzed. One attractive feature of the proposed approach is that an optimal solution is more realistic than the conventional approach because it satisfies physical constraints, such as the ramping constraint.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.3
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• pp.149-155
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• 2004

This paper presents how to find proper operating points of FACTS devices to enhance the steady-state security level considering line contigency analysis. Three generic types of FACTS devices such as series controllers, shunt controllers, and series-shunt controllers are introduced and applied to moximize a security margin and to minimize security indices. Security indices related to line flows and bus voltages are utilized and minimized iteratively in this paper. Contingency analysis is performed to detect the most severe single line fault. In various load conditions, FACTS devices are tested to establish appropriate preventive or corrective action without generation re-dispatching or load shedding. The FACTS operation scheme is verified on the IEEE 57-bus system in a line-faulted contingency.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.4D
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• pp.617-626
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• 2006

The purpose of contingency estimate is to manage the increase in construction cost and the extension of the term of works due to the inevitable occurrence of uncertain situations. The aim of contingency strategies have two intentions. One thing, can be called a passive strategy, gets ready for construction cost increase due to uncertainty factors, the other thing, can be called a active strategy, gets rid of the obstruction factors of work prior to construction performance. Therefore, from the view point of medium and long term, there is necessary to accumulate data in conjunction with design modification cases and carefully analyze uncertainty factors from construction types and characters. Therefore, this thesis will analyze design modification case at a special work such as highway and select factors that affect construction cost and present contingency estimate process using regression analysis.