• 정보관리학회지
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• 제40권1호
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• pp.1-21
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• 2023

본 연구는 텍스트 분류를 위한 효율적인 자질선정 방법으로 자질 순위화 기법의 성능을 구체적으로 검토하였다. 지금까지 자질 순위화 기법은 주로 문헌빈도에 기초한 경우가 대부분이며, 상대적으로 용어빈도를 사용한 경우는 많지 않았다. 따라서 텍스트 분류를 위한 자질선정 방법으로 용어빈도와 문헌빈도를 개별적으로 적용한 단일 순위화 기법들의 성능을 살펴본 다음, 양자를 함께 사용하는 조합 순위화 기법의 성능을 검토하였다. 구체적으로 두 개의 실험 문헌집단(Reuters-21578, 20NG)과 5개 분류기(SVM, NB, ROC, TRA, RNN)를 사용하는 환경에서 분류 실험을 진행하였고, 결과의 신뢰성 확보를 위해 5-fold cross validation과 t-test를 적용하였다. 결과적으로, 단일 순위화 기법으로는 문헌빈도 기반의 단일 순위화 기법(chi)이 전반적으로 좋은 성능을 보였다. 또한, 최고 성능의 단일 순위화 기법과 조합 순위화 기법 간에는 유의한 성능 차이가 없는 것으로 나타났다. 따라서 충분한 학습문헌을 확보할 수 있는 환경에서는 텍스트 분류의 자질선정 방법으로 문헌빈도 기반의 단일 순위화 기법(chi)을 사용하는 것이 보다 효율적이라 할 수 있다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 A
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• pp.105-107
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• 2002

This paper presents a algorithm for contingency ranking using the real power ratio. The fundamemtal cause of voltage collapse is considered due to excessive power trnsfer through the line. To obtain contingency ranking, maximum real power tansferred to the load is obtained when load impedance $Z_r$ equal to line impedance $Z_s$. This algorithm is verified by simulation on a 6-bus test system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 학술대회 논문집 전문대학교육위원
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• pp.146-148
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• 2002

This paper presents a algorithm for contingency ranking using the real power ratio, The fundamemtal cause of voltage collapse is considered due to excessive power trnsfer through the line To obtain contingency ranking, maximum real power tansferred to the load is obtained when load $impedance^{Z_r}$ equal to line $impedance^{Z_s}$, This algorithm is verified by simulation on a 6-bus test system.

• Journal of Electrical Engineering and Technology
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• 제4권4호
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• pp.438-442
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• 2009

Voltage instability is a phenomenon that could occur in power systems due to stressed conditions. The result would be an occurrence of voltage collapse leading to total blackout of the system. Therefore, voltage collapse prediction is an important part of power system planning and operation, and can help ensure that voltage collapse due to voltage instability is avoided. Line outages in power systems may also cause voltage collapse, thereby implying the contingency in the system. Contingency problems caused by line outages have been identified as one of the main causes of voltage instability in power systems. This paper presents a new technique for contingency ranking based on voltage stability conditions in power systems. A new line stability index was formulated and used to identify the critical line outages and sensitive lines in the system. Line outage contingency ranking was performed on several loading conditions in order to identify the effect of an increase in loading to critical line outages. Correlation studies on the results obtained from contingency ranking and voltage stability analysis were also conducted, and it was found that line outages in weak lines would cause voltage instability conditions in a system. Subsequently, using the results from the contingency ranking, weak areas in the system can be identified. The proposed contingency ranking technique was tested on the IEEE reliability test system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 학술대회 논문집 전문대학교육위원
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• pp.95-98
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• 2000

This paper presents a technique for contingency ranking using line capacity calculation method and outage distribution factors (LODF) which are established by generation shift distribution factors from DC load flow solutions. By using the LODF, the line flow can be calculated a ccording to the modification of base load flow if the contingency occur. To obtain contingency ranking, maximum power tansferred to the load is obtained when load impedance $Z_r$ equal to line impedance $Z_s$. The proposed algorithm has been validated in tests on a 6-bus test system.

• 조명전기설비학회논문지
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• 제12권1호
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• pp.20-25
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• 1998

본 논문은 전력설비의 신속한 상정사고 선택을 위한 앨고리즘을 제시한다. 이 방법은 DC법에 의한 선로와 모선사이의 감도계수인 GSDF(Generation Shigt Distribution Factor)를 이용하여 계산되는 선로개방분배계수 (LODF : Line Outage Distribution Factor)를 사용하여 정상상태에서의 선로조류로부터 상정사고시의 선로조류를 계산하였다. 상정사고 선택을 신속히 하기 위하여 정상상태에서 용량대비 선로조류가 35〔%〕(154〔kV〕에서는 60〔%〕)이상의 선로만을 대상으로 하였다. 본 논문에서 제시한 앨고리즘 및 프로그램의 효율성을 입증하기 위하여 6모선 11선로 모델계통을 선정하여 적용하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 B
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• pp.760-763
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• 1996

This paper presents an algorithm for the contingency ranking in a power system. The method utilizes line outage distribution factors(LODF) which are established from DC load flow solutions. The LODF are formulated using changes in network power generations to simulate the outaged line from the network. To abtain better ranking. one can take a line loading of 60% over into account in the computation of PI. The proposed algorithm has been validated in tests on a 6-bus test system.

• International Journal of Contents
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• 제14권3호
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• pp.46-52
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• 2018

The objective of this study was to determine the status of star chart game applications in the Google play store in Korea. The share of game genres in paid and free star charts of game applications was searched. Also, the average reviewer's rating, average number of reviews, and average age rating based on the genre of paid and free star charts of game applications, and the average price of paid applications based on genre were analyzed. Hypothesis tests for the differences in average reviewer's rating, average number of reviews, average age rating according to the genre of game applications were performed. Also, hypothesis tests for the differences in average reviewer's rating, average number of reviews, average age rating between the paid and free game applications along with the hypothesis test for the differences in price according to the genre of paid game applications were performed. Lastly, hypothesis tests for the correlation between the start chart ranking and number of reviews in association with the correlation between the start chart ranking and reviewer's rating were performed. Statistically significant differences in average reviewer's rating, average number of reviews, average age rating according to the genre of game applications, and between the paid and free game applications were verified. However, the correlation between the start chart ranking and number of reviews in association with the correlation between the start chart ranking and reviewer's rating were not statistically significant.

• 인지과학
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• 제13권1호
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• pp.1-11
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• 2002

본 논문에서는 먼저 Anchor Text의 단어들이 키워드로 적합한지 TFIDF를 이용하여 테스트하였다. 그 결과는 가중치가 높아서 키워드로 적합한 단어가 있었는가 하면. 아예 문서에 나오지도 않는 단어가 있어 키워드로 적합하지 않은 단어도 있었다. 이를 해결하기 위하여 새로운 키워드 추출 방법을 제시하였다. 본 논문에서는 적합하지 않은 키워드를 제거함으로써 새로운 키워드를 만들어 내고 TFIDF값을 각 키워드의 가중치로 이용하여 Ranking이 가능하게 하였다. 이렇게 추출된 키워드는 기존의 방법보다 정확도가 높아졌음 증명했다.

• 대한안전경영과학회:학술대회논문집
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• 대한안전경영과학회 2012년 춘계학술대회
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• pp.579-583
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• 2012

The Design of Experiment (DOE) is a most practical technique when establishing an optimal condition for production technology in Six Sigma innovation project. This research proposes the assessment of properties of error terms, such as normality, equal variance, unbiasedness and independence. The properties of six nonparametric ranking techniques for checking normality assumption are discussed as well as run test which is used to identify the randomness, and to check unbiased assumption. Furthermore, Durbin-Watson (DW) statistics and ARIMA (p,d,q) process are discussed to identify the serial correlation.