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Corporate Bond Rating Using Various Multiclass Support Vector Machines (다양한 다분류 SVM을 적용한 기업채권평가)

  • Ahn, Hyun-Chul;Kim, Kyoung-Jae
    • Asia pacific journal of information systems
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    • v.19 no.2
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    • pp.157-178
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    • 2009
  • Corporate credit rating is a very important factor in the market for corporate debt. Information concerning corporate operations is often disseminated to market participants through the changes in credit ratings that are published by professional rating agencies, such as Standard and Poor's (S&P) and Moody's Investor Service. Since these agencies generally require a large fee for the service, and the periodically provided ratings sometimes do not reflect the default risk of the company at the time, it may be advantageous for bond-market participants to be able to classify credit ratings before the agencies actually publish them. As a result, it is very important for companies (especially, financial companies) to develop a proper model of credit rating. From a technical perspective, the credit rating constitutes a typical, multiclass, classification problem because rating agencies generally have ten or more categories of ratings. For example, S&P's ratings range from AAA for the highest-quality bonds to D for the lowest-quality bonds. The professional rating agencies emphasize the importance of analysts' subjective judgments in the determination of credit ratings. However, in practice, a mathematical model that uses the financial variables of companies plays an important role in determining credit ratings, since it is convenient to apply and cost efficient. These financial variables include the ratios that represent a company's leverage status, liquidity status, and profitability status. Several statistical and artificial intelligence (AI) techniques have been applied as tools for predicting credit ratings. Among them, artificial neural networks are most prevalent in the area of finance because of their broad applicability to many business problems and their preeminent ability to adapt. However, artificial neural networks also have many defects, including the difficulty in determining the values of the control parameters and the number of processing elements in the layer as well as the risk of over-fitting. Of late, because of their robustness and high accuracy, support vector machines (SVMs) have become popular as a solution for problems with generating accurate prediction. An SVM's solution may be globally optimal because SVMs seek to minimize structural risk. On the other hand, artificial neural network models may tend to find locally optimal solutions because they seek to minimize empirical risk. In addition, no parameters need to be tuned in SVMs, barring the upper bound for non-separable cases in linear SVMs. Since SVMs were originally devised for binary classification, however they are not intrinsically geared for multiclass classifications as in credit ratings. Thus, researchers have tried to extend the original SVM to multiclass classification. Hitherto, a variety of techniques to extend standard SVMs to multiclass SVMs (MSVMs) has been proposed in the literature Only a few types of MSVM are, however, tested using prior studies that apply MSVMs to credit ratings studies. In this study, we examined six different techniques of MSVMs: (1) One-Against-One, (2) One-Against-AIL (3) DAGSVM, (4) ECOC, (5) Method of Weston and Watkins, and (6) Method of Crammer and Singer. In addition, we examined the prediction accuracy of some modified version of conventional MSVM techniques. To find the most appropriate technique of MSVMs for corporate bond rating, we applied all the techniques of MSVMs to a real-world case of credit rating in Korea. The best application is in corporate bond rating, which is the most frequently studied area of credit rating for specific debt issues or other financial obligations. For our study the research data were collected from National Information and Credit Evaluation, Inc., a major bond-rating company in Korea. The data set is comprised of the bond-ratings for the year 2002 and various financial variables for 1,295 companies from the manufacturing industry in Korea. We compared the results of these techniques with one another, and with those of traditional methods for credit ratings, such as multiple discriminant analysis (MDA), multinomial logistic regression (MLOGIT), and artificial neural networks (ANNs). As a result, we found that DAGSVM with an ordered list was the best approach for the prediction of bond rating. In addition, we found that the modified version of ECOC approach can yield higher prediction accuracy for the cases showing clear patterns.

A Study on the Pain in Patients with Temporomandibular Disorders using Korean Pain Rating Scale (측두하악장애환자에서 한국어 통증척도를 이용한 통증에 관한 연구)

  • Yoing-Gyu Bae;Kyung-Soo Han
    • Journal of Oral Medicine and Pain
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    • v.19 no.2
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    • pp.169-180
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    • 1994
  • The aim of this study was to compare pain descriptions in common dental patients with those in patients with Temporomandibular disorders(TMDs). The study sample consisted of 104 common dental patients and 74 patients with TMDs, and their chief complaint was pain, Subjects were classified common dental pain group and TMDs pain group, respectively. All the subjects completed Korean Pain Rating Scale(KPRS) on first visit. KPRS contains 90 pain terms, which divided into 20 subclasses in 3 dimensions. Each subclass contains 3-6 pain terms. each patient had chosen only one term from each subclass. If there was no proper term, subject could pass the subclass without completion. Words chosen were categorized into sensory, affective, miscellaneous and total dimension. Thereafter they were processed and analyzed by SPSS/PC+ statistical package program with respect to rank values, scale values, number of words chosen and frequency of each subclass. The obtained results of this study were as follows : 1. Total mean number of words chosen was 7.6. 2. Chronic patients groups with Temporomandibular disorders had chosen more freuently from the subclasses in affective dimension than the patients in acute common dental pain group. 3. Frequency of affective dimension was higher in chronic patients groups with Temporomandibular disorders than that of acute patients group with Temporomandibular disorders. 4. Chronic patients group with Temporomandibular disorders had higher frequency in constrictive pressure pain, traction pressure pain, dull pain and fatigue-related pain terms than acute common dental patients group. 5. Acute patients group with Temporomandibular disorders had higher frequency in traction pressure pain and dull pain terms but had lower frequency in chemical pain, peripheral nerve pain and cold pain terms than acute common dental patients groups. 6. There were high positive correlation between the scale- and rank-value in the pain rating index.

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Connectedness rating among commercial pig breeding herds in Korea

  • Wonseok Lee;JongHyun Jung;Sang-Hyon Oh
    • Journal of Animal Science and Technology
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    • v.66 no.2
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    • pp.366-373
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    • 2024
  • This study aims to estimate the connectedness rating (CR) of Korean swine breeding herds. Using 104,380 performance and 83,200 reproduction records from three swine breeds (Yorkshire, Landrace and Duroc), the CR was estimated for two traits: average daily gain (ADG) and number born alive (NBA) in eight breeding herds in the Republic of Korea (hereafter, Korea). The average CR for ADG in the Yorkshire breed ranges from 1.32% to 28.5% depending on the farm. The average CR for NBA in the Yorkshire herd ranges from 0% to 12.79%. A total of 60% of Yorkshire and Duroc herds satisfied the preconditions suggested for genetic evaluation among the herds. The precondition for the genetic evaluation of CR for ADG, as a productive trait, was higher than 3% and that of NBA, as a reproductive trait, was higher than 1.5%. The ADG in the Yorkshire herds showed the highest average CR. However, the average CR of ADG in the Landrace herds was lower than the criterion of the precondition. The prediction error variance of the difference (PEVD) was employed to assess the validation of the CR, as PEVDs exhibit fluctuations that are coupled with the CR across the herds. A certain degree of connectedness is essential to estimate breeding value comparisons between pig herds. This study suggests that it is possible to evaluate the genetic performance together for ADG and NBA in the Yorkshire herds since the preconditions were satisfied for these four herds. It is also possible to perform a joint genetic analysis of the ADG records of all Duroc herds since the preconditions were also satisfied. This study provides new insight into understanding the genetic connectedness of Korean pig breeding herds. CR could be utilized to accelerate the genetic progress of Korean pig breeding herds.

Determination of the Initial Tendon Force using Rating Factor Equation in Composite Girders Strengthened with External Tendons (외부 긴장재로 보강된 강합성보의 내하율 산정식을 이용한 초기 긴장력 결정)

  • Choi, Dong Ho;Chung, Sang Hwan;Yoo, Dong Min
    • Journal of Korean Society of Steel Construction
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    • v.17 no.5 s.78
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    • pp.527-536
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    • 2005
  • A method of reinforcement using external tendons has been found to be one of the effective techniques of reinforcement and its application is increasing. In this paper, the method to calculate the initial tendon force is proposed for the improvement of load-carrying capacity in existing steel-concrete composite bridges. An equation for the increment of tendon force was derived for tendon configurations and live load types, and the effect of reinforcement in a composite beam was numerically studied. The method to calculate the number of tendon and initial tendon force was presented by proposing the new method to calculate the rating factor, which considers the increment of tendon force. The method was shown to be effective for an existing steel-concrete bridge.

A Comparative Study of ADL, IADL in Urban and Rural Elderly - Taejon, Koje Area (일 도시.농촌노인의 ADL, IADL 비교연구 -대전.거제지역을 중심으로-)

  • Li, Chun-Yu;Kim, Keum-Ee;Kim, Hyun-Li
    • Research in Community and Public Health Nursing
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    • v.8 no.2
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    • pp.225-236
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    • 1997
  • This study was conducted to investigate the elderly in urban and rural ares. The subjects were selected in a convenient sampling and the total number was 189(Urban : 95, Rur al : 94). The data were collected by one to one interviews in the period of Sep. 1-30, 1995(Koje) and March 15-28, 1997 (Taejon). The study tools for this study were 1) ADL and IADL 2) Self rating scores for health status. The data were analyzed by percentage, T-test, ANOVA, $X^2$ Test, Pearson correlation coefficiency by SPSS pc WIN. 7.0 program. The results were as follows: 1. The self rating score for health status of the elderly in urban area was lower than that of the rural when compared in the same age group. 2. In the comparison of ADL scores between the elderly in urban and rural areas, there was no statistically significant difference. The IADL score of the rural elderly were higher than that of the urban elderly and there was a statistically significant difference. 3. In the comparison of ADL & IADL scores according to the self rating score for health status, there was a statistically significant difference among health status levels.

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Comparative Analysis of Current Science Textbooks on Category (중학교 과학 교과서의 범주별 분석 비교)

  • Koo, Soo-Jeong;Choi, Don-Hyung
    • Journal of The Korean Association For Science Education
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    • v.12 no.2
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    • pp.97-107
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    • 1992
  • ln this study, we analyzed 5 science textbooks currently used for the 7th graders quantitatively by using the science textbook rating system of Collette and Chiappetta(1986), making meta-analysis of the results of 17 graduate school students of Seoul National University. The rating system consists of 11 categories with detailed items respectively : content, organization, reading level, instruction approach, illustrations, end-chapter teaching aids, laboratory activities in text and/or accompanying manual, teacher aids, indices and glossaries and mechanical makeup of text. Each item in the checklist is to be given between one and five points and the total number of possible points in this rating system is 290. It was shown that 5 science textbooks currently used for 7th-year-students were all "poor" in terms of total points and had, at large, uniformed results especially in 10 items; 7 items concerning moral and ethical implications of science, vocabulary lists, accompanying laboratory manual, annotated editions for test, supply list for laboratory program, student workbook and glossary with low points, while 3 items concerning facilities needed for laboratory activities, activities relevant to the content and textbook size with high points. A Science teachers could get a broad view with a correct impression of the books usefulness in making an evaluation of available textbooks.

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The Conformity Effect in Online Product Rating: The Pattern Recognition Approach

  • Kim, Hyung Jun;Kim, Songmi;Kim, Wonjoon
    • International Journal of Contents
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    • v.13 no.4
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    • pp.80-87
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    • 2017
  • Since the advent of the Internet, and the development of smart devices, people have begun to spend more time in online platforms; this phenomenon has created a large number of online Words of Mouth (WOM) daily. Under these changes, one of the important aspects to consider is the conformity effect in online WOM; that is, whether an individual's own opinion would be influenced by the majority opinion of other people. This study, therefore, investigates whether there is the conformity effect in online product ratings for Amazon.com using the method called Markov Chain analysis. Markov Chain analysis considers the stochastic process that satisfies the Markov property, and we assume that the generation of online product ratings follows the process. Under the assumption that people are usually independent when they express their opinion in online platforms, we analyze the interdependency among rating sequences, and we find weak evidence that there exists the conformity effect in online product rating. This suggests that people who leave online product ratings consider others' opinions.

Machine Learning-based model for predicting changes in user evaluation reflecting the period of the product (제품 사용 기간을 반영한 기계학습 기반 사용자 평가 변화 예측 모델)

  • Boo Hyunkyung;Kim Namgyu
    • Journal of Korea Society of Digital Industry and Information Management
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    • v.19 no.1
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    • pp.91-107
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    • 2023
  • With the recent expansion of the commerce ecosystem, a large number of user evaluations have been produced. Accordingly, attempts to create business insights using user evaluation data have been actively made. However, since user evaluation can change after the user experiences the product, it is difficult to say that the analysis based only on reviews immediately after purchase fully reflects the user's evaluation of the product. Moreover, studies conducted so far on user evaluation have overlooked the fact that the length of time a user has used a product can affect the user's product evaluation. Therefore, in this study, we build a model that predicts the direction of change in the user's rating after use from the user's rating and reviews immediately after purchase. In particular, the proposed model reflects the product's period of use in predicting the change direction of the star rating. However, since the posterior information on the duration of product use cannot be used as input in the inference process, we propose a structure that utilizes information about the product's period of use using an auxiliary classifier. As a result of an experiment using 599,889 user evaluation data collected from the shopping platform 'N' company, we confirmed that the proposed model performed better than the existing model in terms of accuracy.

Determination of the Initial Tendon Force in Two-span Continuous Steel-Concrete Composite Beam Strengthened with External Tendons (외부 긴장재로 보강된 2경간 연속 강합성보의 초기 긴장력 결정)

  • Choi, Dong Ho;Yoo, Dong Min;Jung, Jae Dong;Kim, Eun Ji
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.10 no.4
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    • pp.145-154
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    • 2006
  • This paper presents a method to enhance the load carrying capacity for a two-span continuous steel-concrete composite beam strengthened with external tendons. The tendon is placed at the bottom of steel beam where the positive bending moment occurs. This results in the reduction of the negative bending moment as well as the positive bending moment. This paper describes the procedure to determine the number of tendon and the initial tendon force for the target rating factor in the rating factor equation. An example beam is given to demonstrate the proposed procedure, and it validity is confirmed.

Factors Affecting Webtoon's Success: An Empirical Study (웹툰(Webtoon)의 흥행 결정요인 연구)

  • Yang, Ji Hoon;Lee, Ji Young;Lee, Sang Woo
    • The Journal of the Korea Contents Association
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    • v.16 no.5
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    • pp.194-204
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    • 2016
  • With the fast diffusion of smart media, Webtoon has become popular contents among Korean people. Webtoon's content is being used in various content industries, such as movies and drama, and thus its cultural influence is increasing. Using ordinal Regression analysis, this study tried to find major factors affecting webtoon's success. This study found that readers' rating, number of likes, OSMU, author power, genre, picture style are important factors affecting the success of webtoon. This study has several business implications for the Korean webtoon industry.