The Load Model Composition Method in Power Systems Using Artifcial Neural Network

Rae‑Jun Park,송경빈,Kyungsang Lee 대한전기학회 2020 Journal of Electrical Engineering & Technology Vol.15 No.2

An accurate load model is necessary to improve the accuracy of power systems dynamic stability analysis. Recent studies to estimate accurate load model have mainly been focused on the measurement-based load modeling and the method to estimate a single representative load model called load model composition or load representation. The current load model used for the dynamic stability analysis in South Korea power system was aggregated with the measurement data from only three distribution stations. The proposed algorithm is the load model composition method based on artifcial neural network technique using more measurement data than the algorithm to estimate the current load model. The proposed load model composition method using the artifcial neural network uses the load composition ratio as the input value and the ZIP model parameter, which is the estimation result at each distribution line, as the output value. The measurement data to estimate the parameter were collected from 105 distribution lines of 9 substations. The performance of proposed algorithm was verifed for three perspectives in the case studies. The accuracy of the proposed algorithm has been improved by comparing the measurement data with the calculated result by using the proposed model. The mean absolute percentage error (MAPE) between the measured data and the proposed model is 1.7%. The proposed algorithm could be applied to estimate the representative load model using data measured at multiple measurement points.

조세회피와 발생액에 의한 이익조정이 회사채 신용등급에 미치는 영향

조영래(Cho, Young-Rae),김용(Kim, Yong) 한국산업비즈니스학회 2021 한국비즈니스연구 (비즈니스연구) Vol.5 No.1

본 연구에서는 2011년부터 2015년까지 유가증권시장에 상장된 기업들을 대상으로 신용등급이 상승하거나 또는 하락할 경우에 조세회피 및 발생액에 의한 이익조정이 회사채 신용등급에 어떠한 영향을 미치는 지를 분석하였다. 추가로 조세회피 및 이익조정의 지속성이 신용등급에 어떤 영향을 미치는지에 대해서도 분석하였다. 분석결과는 신용등급이 상승하는 경우에 조세회피가 1% 수준에서 유의적인 음(-)의 관계를 나타내었으며, 조세회피와 신용등급 상승의 상호작용변수는 유의적인 양(+)의 관계를 나타내었다. 이는 조세회피가 직전년도와 비교하여 신용등급이 상승하였을 때는 조세회피를 하려는 경향이 감소하기 때문이며, 또한 신용평가기관에서 신용등급이 상승할 때 조세회피는 감소할 것이라고 예측하여 보고된 이익을 그대로 반영하였기 때문이라고 판단된다. 그러나 신용등급이 하락하는 경우에는 이와 정반대의 결과를 도출하였다. 그러나 발생액에 의한 이익조정은 신용등급과 유의적인 관계를 나타내지 못하였다. 추가로 지속성이 회사채 신용등급에 영향을 미치는지를 검증하였는데, OLS회귀분석과 순서형 로짓회귀분석 모두 일부 이익조정(수정 Jones모형)의 경우 5% 수준에서 유의적인 음(-)의 관계를 나타내었다. 따라서 이익조정의 지속성은 신용등급에 부정적인 영향을 미친다고 볼 수 있다. 다만, 이들 관계는 측정치에 따라 차이가 나타나고 있다. 이러한 분석결과는 신용평가기관이 조세회피를 제대로 포착하지 못함으로써 신용위험을 왜곡시키고 나아가 신용등급에 대한 신뢰성을 떨어뜨릴 수 있다는 점을 시사하는 것으로 판단된다. This study empirically analyzed how tax avoidance affects bond credit ratings of listed companies on the korea exchange from 2011 to 2015. The results of this study are summarized as follows. First, the relationship between tax avoidance, earnings management and bond credit ratings was not statistically significant in all models. But In the case of a rise in bond credit rating, the relationship between the five years of accumulated cash effective tax rate(cashETR) were showed a significant negative(-) relationship at a 1% level. Also, if the bond credit rating declines, the results is the opposite of the case where the bond credit rating rises. Second, in determining whether continuous tax avoidance affects bond credit rating ratings, either the OLS analysis, or ordered logistics regression analysis, showed a significant negative(-) relationships only in the Jones Model at a 5% level. Third, The interaction effect of the decline in credit rating and persistence showed a significant negative(-) relationship at 1% level in all three models. Thus, the persistence of the tax avoidance can be seen to affect bond credit rating when combined with other factors that can interact. The results of this study suggest that many companies still avoid tax, but credit rating agencies are not able to capture them properly, thus distorting credit risk and decreasing credibility of credit rating.

기업가지향성과 조직문화가 기업성과에 미치는 영향에 관한 연구

조형래(Jo, Hyung-Rae) 글로벌경영학회 2012 글로벌경영학회지 Vol.9 No.4

조직성과에 관한 오랜 연구에서는 그에 영향을 주는 요인들을 기업이 보유하고 있는 자원역량, 환경요 인, 전략적 구성, 경영관리 특성 등으로 보고 그러한 요인들을 중심으로 주요한 분석들을 수행해 왔다. 본 연구에서는 기업들의 성과에 영향을 줄 것으로 기대되는 조직문화적인 변수들을 중심으로 분석하였 다. 이를 통해 조직의 더 근원을 이루는 요소들을 분석함으로써 기업들에게 다른 시사점을 전해 줄 수있을 것으로 기대할 수 있다. 구체적으로 기업성과에 영향을 주는 조직문화의 요인으로서 기업가지향성, 참여적 문화, 사명감 문화 등을 고려하였다. 이론적 고찰의 결과 기업가지향성은 신제품개발에의 성과를 비롯한 여러 기업성과에 영향을 주는 요인으로 나타났고 참여적 문화, 사명감 문화도 기업의 여러 성과에 영향을 주는 요인으로 분석되었다. 따라서 연구의 모형과 가설은 이들 변수들이 기업성과에 어떻게 영향을 주는가 라는 점에 초점을 맞추어 수립되었다. 실증분석을 위해 89개의 기업체 자료들이 수집되 었다. 요인분석 결과 기업가지향성, 참여적 문화, 전략적 초점, 비전 공유의 4가지 변수들이 최종적인 독립변수로 선정되었고 기업성과는 재무적 성과, 비재무적성과, 전반적 성과의 세 가지로 구성되었다. 가설검증을 위한 회귀분석 결과 전략적 초점은 모든 종속변수에 중요하게 영향을 주는 변수로 나타났다. 기업가지향성은 비재무적 성과에 영향을 주는 것으로 나타났다. 조직문화 차원의 변수들이 고려되었으 므로 향후 기업들에서 얻을 수 있는 시사점들이 그에 따라 제시되었다. 즉 향후 기업에서 전략적 초점을 가지도록 하는 명시적인 경영 실무 뿐만 아니라 이러한 점들이 기업의 하나의 저변을 이루는 문화로서 정착될 수 있는 노력이 필요하다는 점을 기업들에게 말해 주고 있다. Until now most research on the performance of firms has dealt with management characteristics, strategic formulation, and firm capabilities as major influential variables. This study analyze the organizational cultural variables mainly which are expected to influence the performance of firms. We may anticipate to give some implications to companies through the analysis of more fundamental elements of an organization. Specifically entrepreneurial orientation, involvement culture, mission culture are considered as cultural variables. By theoretical review, we found that entrepreneurial orientation had influenced various firm performance including new product development performance as well as involvement culture and mission culture. Accordingly, we established research model and hypotheses focusing on how these variables influences firm performance. For empirical analysis, 89 samples of firms were gathered. By the result of factor analysis, we selected 4 main independent variables of entrepreneurial orientation, involvement culture, strategic focus, share of vision and 3 main dependent variables of financial performance, non-financial performance, comprehensive performance. After we implemented the regression analysis for the hypotheses testing, we found that strategic focus have significant influence on all of the performace indicators and that entrepreneurial orientation have significant influence on the non-financial performance. As we adopted variables of organizational cultural variables as main research variables, the implications of this research suggest that company should stress not only on the explicit management practices related to the strategic focus but also on the efforts which make these aspects to be set up as the culture underlying the organization.

二十一世紀 韓國體育·스포츠의 果題와 展望

李來華 慶北大學校 師範大學 體育學硏究會 1991 體育學會誌 Vol.19 No.-

When we meet the 1945 Liberation of Korea in past days, we need to recollect and appreciate the result of the confusion, the stupefaction, the disorder and the defenselessness because everything isn't the request of the preparation and the counterproposal, though it is unavoidable. And we need the wisdom and the decision to ruminate it today. Who considers any athletics and sports the desirable Korean athletics and sports in the 21th century? It is too much to say that the history of the athletics and sports has been described as the answer to this question. The theory of the athletics and sports is also the answer of this question. It isn't produced without the presnet rigid criticism and the prospect in the future. When politics, economy, culture and education(athletics)in the past days are at a crisis, we have conquered it by resisting and contending against the persecution because the new axiology is presented boldly, The change of the new axiology from the old axiology is born not the order from transcendental existence but the contents from the old one. And the power to have promoted the human history is treasured up the contradiciton of the situation. From this viewpoint we have to present and grope for the athletics and sports in the 21th century.

Aristoteles의 敎育思想에 나타난 體育觀 : 그 現代的인 意義 Their Modern Significance

李來華 慶北大學校 1976 論文集 Vol.22 No.-

The following is a summary of physical education Views appeared in Aristoteles's thought of education. 1. First of all, Aristoteles pointed out physical superiority in the nature of physical culture as an important element of individual happiness which is the ultimate goal of state and his views left us profound implicit suggestions and lessons in our modern health education. 2. He wmarned the precoccupied sonse of then people only for the results of games in athletic activities. His views valued highly of the processes than the results, emphasizing the harmony bet-ween pleasure and pain primarily in the merit of patience and hardship toward the altimate goal of mental and physical development where lies a need for physical culture. 3. He evolved the methodology and the contents of physical culture in its three phases of analysis of intrinsic Nature, Habit, and Conscience and denounced the Spartan phsical training which produced deforming physical look and brutality, defining it as most vicious system. He also made a critical warning against the heavy slant only on techniques in the games or play activites while emphasizing to place a focuss in developing the resourceful qualities adaptable to the behavior of free man to an extent possible. 4. He, from a view point of the national eugenics, respected highly of prenatal influence together with health of the pregnant and prescribed the qualities necessary for marriage. He stressed these factors should come under the control of state and further, extended his views to the formation of construtive health environment of state and of sound sxual ethics, which are now presenting us considerable hints precept.

ISO 14001(환경경영체제)의 효율적 연구

이내형 瑞逸大學 1998 論文集 Vol.16 No.-

Socrates. 그 體育的 示唆와 思想史的 敎訓 : 體育哲學의 原初的 吟味

李來華 경북대학교 1978 논문집 Vol.10 No.-

The intention of this paper is to understand the outlook on life and the educational philosophy of Socrates which are inseparable from his practical knowledge about physical education, and to search for the origins of his philosophy of physical education. My purpose is to recall salient implications and the great instruction he gives to the present; these implications are summarized in the following order; 1) Natural philosophy as it existed before Socrates changed after the incident of the Oracle at Delphi, which Socrates had interpreted as an approval of agonoticism. Thereafter, he presented and established a theory of philosophy which was primarily based on the importance of humanness, and on his belief in Daimonion. 2) Throughout his life, Socrates never lost the virtue of moderation, which he made a religion of, through will power and self-control. His thinking on education was that well-trained individuals are key to keeping order in the home,and that well-administered governmetns make it possible to ensure peace in the world. To this he related his practical wisdom which comes from his thought that wisdom means virtue. 3) The philosophy of Socrates is grounded on the conviction that justice comes about only through the moderate of the good and the beautiful. In the course of this, the individual must pay attention to Eros, love of teacher, and his soul for his and government's happiness. 4) Socrates took the lead in putting his wisdom into practice so that to be conscious of wisdom on both part of the individual and citizen might be heightened to the state of virtue. For this reason we may call him the teacher of the human race. 5) The dogmas in the philosophy of Socrates are that self should be controlled, wisdom should be treated as virtue, and wisdom, as practice. Consideration of the status quo of the present atelete would reveal that they are lacking in subjectivity and consistency between what they say and what they do. The same goes for sports in action: they are losing their educational function. This can be due to the difference between theory and reality. On this point, it is urgent to adopt the philosophy of Socrates into the present sports. 6) Socrates's view of humanbeing is biased in favor of the spirit; however, when it comes to health problem, we can find that he put a great emphasis on the necessity of having information about what it is and how to be healthy, and that he insisted on the rightness of practising good health for oneself, which is the enact reflection of the appearence and reality of today's health education. 7) The tendency to regard sports as a hobby, or as a self-advertisement, and to play sports for the sake of victory provides clear evidence that today's physical education is derailed out of its original purpose and principle, and even in a sense, doing harm to good health. Compared with ths phenomenon, the moral importance and the necessity of the physical and spiritual discipline declared by Socrates long time ago, now gives us some meaningful implications and valuable instruction.

신경회로망을 이용한 인쇄체 한글 인식에 관한 연구

장래복,이근영 成均館大學校 科學技術硏究所 1992 論文集 Vol.43 No.1

본 논문에서는 신경회로망을 이용한 인쇄체 한글 문자의 인식에 대해서 연구하였다. 입력 방식은 스캐너를 사용하였고 문자 분리 및 세선화과정을 거친후 자모를 분리하였다. 배율 조정과 음영부호 방식을 사용하여 데이터를 압축하였고 모음과 자음을 분리하여 역전파 신경회로망을 학습하였으며, 실험 결과 자음과 모음 각각에 대하여 98%의 인식율을 얻을 수 있었다. This paper describes recognition of printed KOREAN characters using multilayer perceptrons. Scanned image is segmented and thinned as preprocessings. Through normalizing the size of the character patterns and obtaining shadow codes from each segmented patterns, input data of the neural network are reduced significantly. Two separate networks are used to train the vowel and consonant patterns respectively and trained by using back propagation algorithm. Result of this method showed same recognition rate of about 98% on both vowel and consonant characters.

勞動環境變化와 韓國勞使關係의 進路

朴來榮 홍익대학교 경제연구소 1996 經濟硏究 Vol.11 No.-

國際資源波動의 展開 : focussed on Mineral Resources 鑛物資源을 中心으로

朴來榮 弘益大學校 1974 弘大論叢 Vol.6 No.-

The Middle-east War in October, 1973 has induced the oil shock which has brought about the depression and the galloping inflation all over the world. This oil crise, however, seems to be one of the critical outbreaks of the growing worse of world resource situations, because the symptoms of current resource crises have already appeared from the later 1960's The situations around the mineral resources have been degenerated from the beginning of later half of this century. The demand for some important mineral resources were rapidly increased due to the diversification of the world resource consumption; the most developed countries took the pattern of higher consumption of mineral resources for raising the level of living of their peoples, the resource consumption of later industrialized nations were accerelated by taking the capital using methods of production and the proportion of developing countries to the total world resource consumption was also expanded for their economic growth through industrialization. Nevertheless, the constraints on resource supply which have been immanced during long period due to the characteristics of natural resource and to the oligopoly of the supply channel were not mitigated. Geographic maldistribution as well as the risky and expensive discoveries or exploitations of the natural resources are the main constraint coming from the characteristics. For these restrictions, most of the resource development have been oligopolied by large international capital from the beginning and the quantities and prices of the resources have also be controlled by these major companies of the rich countries. These changing situation of demand and supply of the mineral resources, however, is not the direct causes but the potentiality of current cirses. The direct and cirtical causes have come from the changing power relation between the developed nations and the developing nations, and from the severe competition among the developed countries who have not owned enough resources. Most of the developing countries who have owned the natural resources asked to the sovereignty, while the developed countries want to continue the existing interational legal relations on the problems of the natural resources. Up to 1950's, international resource supplies were commanded by mighty nations and their capital. But the power equilibrium ruled by these mighty nations have broken out by the combinating power of the developing countries since the resolution on the sovereignty of natural resources have been adopted by the 21th general meeting of the United Nations in 1966. The groups of the developing countries who owned the natural resources, such as OPEC and CIPEC, have also affected to the change of power relation between the resource owned countries and the resource consuming countries. The blasting fuse of current resource crise is the intensifing competition for buying up the resources among the developed countries who have not owned or who needed more resources just for their national interests. The United States of America and England have stimulated their private companies, while West Germany, France and Italy have formulated the national companies for taking more resources. Japanese who could have accumulated the dollars by expanding their export during two decades after the Korean War have urged to corner the resources which needed for continuing growth of their economy. The spiral of rise-up and buying-up of the resources which have been aroused by the Japanese atteck and the America's response seems to be continued in near future.