• Title/Summary/Keyword: Risk Rating System

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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.

Integration of Similarity Values Reflecting Rating Time for Collaborative Filtering

  • Lee, Soojung
    • Journal of the Korea Society of Computer and Information
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    • v.27 no.1
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    • pp.83-89
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    • 2022
  • As a representative technique of recommender systems, collaborative filtering has been successfully in service through many commercial and academic systems. This technique recommends items highly rated by similar neighbor users, based on similarity of ratings on common items rated by two users. Recently research on time-aware recommender systems has been conducted, which attempts to improve system performance by reflecting user rating time of items. However, the decay rate uniform to past ratings has a risk of lowering the rating prediction performance of the system. This study proposes a rating time-aware similarity measure between users, which is a novel approach different from previous ones. The proposed approach considers changes of similarity value over time, not item rating time. In order to evaluate performance of the proposed method, experiments using various parameter values and types of time change functions are conducted, resulting in improving prediction accuracy of existing traditional similarity measures significantly.

A Study on Utilization Ratio and Operation of Transmission Lines (송전선로의 이용률 평가 및 합리적 운영에 관한 연구)

  • Kim, Dong-Min;Bae, In-Su;Cho, Jong-Man;Kim, Jin-O
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.55 no.10
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    • pp.426-432
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    • 2006
  • This paper describes the concepts of Static Line Rating (SLR) and Dynamic Line Rating (DLR) and the computational methods to demonstrate them. Calculation of the line capacity needs the heat balance equation which is also used for computing the reduced tension in terms of line aging. SLR is calculated with the data from the worst condition of weather throughout the year. Even now, the utilization ratio is obtained from this SLR data in Korea. DLR is the improved method compared to SLR. A process for DLR reveals not only improved line ratings but also more accurate allowed line ratings based on line aging and real time conditions of weather. In order to reflect overhead transmission line aging in DLR, this paper proposes the method that considers the amount of decreased tension since the lines have been installed. Therefore, the continuous allowed temperature for remaining life time is newly acquired. In order to forecast DLR, this paper uses weather forecast models, and applies the concept of Thermal Overload Risk Probability (TORP). Then, the new concept of Dynamic Utilization Ratio (DUR) is defined, replacing Static Utilization Ratio (SUR). For the case study, the two main transmission lines which are responsible for the north bound power flow in the Seoul metropolitan area are chosen for computing line rating and utilization ratio. And then line rating and utilization ratio are analyzed for each transmission line, so that comparison of the present and estimated utilization ratios becomes available. Finally, this paper proves the validity of predictive DUR as the objective index, with simulations of emergency state caused by system outages, overload and so on.

Developing Fire-Danger Rating Model (산림화재예측(山林火災豫測) Model의 개발(開發)을 위(爲)한 연구(硏究))

  • Han, Sang Yeol;Choi, Kwan
    • Journal of Korean Society of Forest Science
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    • v.80 no.3
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    • pp.257-264
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    • 1991
  • Korea has accomplished the afforestation of its forest land in the early 1980's. To meet the increasing demand for forest products and forest recreation, a development of scientific forest management system is needed as a whole. For this purpose the development of efficient forestfire management system is essential. In this context, the purpose of this study is to develop a theoretical foundation of forestfire danger rating system. In this study, it is hypothesized that the degree of forestfire risk is affected by Weather Factor and Man-Caused Risk Factor. (1) To accommodate the Weather Factor, a statistical model was estimated in which weather variables such as humidity, temperature, precipitation, wind velocity, duration of sunshine were included as independent variables and the probability of forestfire occurrence as dependent variable. (2) To account man-caused risk, historical data of forestfire occurrence was investigated. The contribution of man's activities make to risk was evaluated from three inputs. The first, potential risk class is a semipermanent number which ranks the man-caused fire potential of the individual protection unit relative to that of the other protection units. The second, the risk sources ratio, is that portion of the potential man-caused fire problem which can be charged to a specific cause. The third, daily activity level is that the fire control officer's estimate of how active each of these sources is, For each risk sources, evaluate its daily activity level ; the resulting number is the partial risk factor. Sum up the partial risk factors, one for each source, to get the unnormalized Man-Caused Risk. To make up the Man-Caused Risk, the partial risk factor and the unit's potential risk class were considered together. (3) At last, Fire occurrence index was formed fire danger rating estimation by the Weather Factors and the Man-Caused Risk Index were integrated to form the final Fire Occurrence Index.

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Risk Assessment for Disaster Reduction in Small-Scale Construction Sites (소규모 건축현장 재해감소를 위한 위험성평가 방안)

  • Choi, Hyun-Jun
    • Journal of the Society of Disaster Information
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    • v.18 no.2
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    • pp.395-404
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    • 2022
  • Purpose: Small-scale construction sites have insufficient systematic safety management activities, and due to the characteristics of the construction site, the production structure is complex due to external environmental factors, and the risk of construction equipment is very high. We would like to propose a checklist method among practical risk assessment techniques that can derive risk factors for disaster prevention at small construction sites and reduce disasters. Method: Risk factors were derived by analyzing literature research and disaster cases, and detailed work for a checklist of risk assessment suitable for small-scale construction sites was classified based on risk factor items. Result: Hazard factors were divided into 6 major categories, and 29 detailed types of work were classified based on actual work types, and 80 detailed works were classified accordingly. Conclusion: By arranging risk factors suitable for small-scale construction sites according to the classification system, the lack of expertise in the construction site can be supplemented, and risk factors can be derived more easily and disaster reduction can be expected through establishment of safety measures.

Comparison of Rating Methods by Disaster Indicators (사회재난 지표별 등급화 기법 비교: 가축질병을 중심으로)

  • Lee, Hyo Jin;Yun, Hong Sic;Han, Hak
    • Journal of the Society of Disaster Information
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    • v.17 no.2
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    • pp.319-328
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    • 2021
  • Purpose: Recently, a large social disaster has called for the need to diagnose social disaster safety, and the Ministry of Public Administration and Security calculates and publishes regional safety ratings such as regional safety index and national safety diagnosis every year. The existing safety diagnosis system uses equal intervals or normal distribution to grade risk maps in a uniform manner. Method: However, the equidistant technique can objectively analyze risk ratings, but there is a limit to classifying risk ratings when the distribution is skewed to one side, and the z-score technique has a problem of losing credibility if the population does not follow a normal distribution. Because the distribution of statistical data varies from indicator to indicator, the most appropriate rating should be applied for each data distribution. Result: Therefore, in this paper, we analyze the data of disaster indicators and present a comparison and suitable method for traditional equidistant and natural brake techniques to proceed with optimized grading for each indicator. Conclusion: As a result, three of the six new indicators were applied differently from conventional grading techniques

A Basic Study on the Derivation of Vulnerability Factors for Safety Management of old Buildings (노후 건축물의 안전관리를 위한 취약성 요소 도출 기본연구)

  • Oh, Gyuho;Cha, Inhyuck;Ahn, Sungjin
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2023.05a
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    • pp.275-276
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    • 2023
  • In order to prevent disaster risks caused by building aging in advance, the prevailing opinion is that it is urgent to actively improve systems such as mandatory safety inspections, and to calculate risks and develop safety management systems due to building aging. The need for systematic risk management continues to be emphasized in the process of safety inspection and repair of old buildings, but the risk management and safety management techniques of each construction entity have not been established in practice. Accordingly, this study aims to analyze the vulnerability factors of aging buildings and provide basic data on the development of a risk rating calculation model for old buildings and the efficiency of safety management systems in the future.

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Decreased Concentration of Plasma Brain-Derived Neurotrophic Factor in Suicide Attempters (자살 시도자에서 혈장 Brain-Derived Neurotrophic Factor 농도 저하)

  • Won, Seong-Doo;Shim, Se-Hoon;Yang, Jong-Chul;Lee, Heon-Jeong;Lee, Bun-Hee;Han, Chang-Su;Kim, Kye-Hyun;Kim, Yong-Ku
    • Korean Journal of Biological Psychiatry
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    • v.12 no.2
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    • pp.189-195
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    • 2005
  • Objects:Some studies have suggested that brain-derived neurotrophic factor(BDNF), one of the most important neurotrophins, is involved in pathophysiology of depression and suicide. This study was performed to determine whether there is an abnormality in plasma BDNF concentration in suicidal attempters. Methods:The subjects were 71 suicidal attempters who visited emergency rooms in multi-medical centers. All subjects had been interviewed by using Structured Clinical Interview for DSM-IV(SCID), Hamilton Depression Rating Scale(HDRS), Young Mania Rating Scale(YMRS), and Positive And Negative Syndrome Scale(PANSS). The severity of the suicidal behavior was measured by Lethality of Suicide Attempt Rating Scale(LSARS) and Risk-Rescue Rating(RRR) system. Seventy-one age, sex, and diagnosis matched non-suicidal psychiatric patients who were consecutively admitted to a psychiatric ward during the same period recruited as psychiatric controls. They were drug-naive or drug-free at least more than 2 months. In addition, 80 healthy controls were randomly selected as normal controls. Plasma BDNF level was measured by the enzyme linked immunosorbent assay(ELISA) methods. Results:In overall F-test, differences of the plasma BDNF levels among the groups were statistically significant(F=20.226, p<0.001). In the multiple comparisons(Scheffe), while mean levels of plasma BDNF between normal controls and non-suicidal psychiatric patients were similar(p=0.984), the BDNF levels of suicidal attempters were lower than those of other two groups(p<0.001). LSARS and RRR did not reveal any significant correlations with BDNF levels in suicidal attempters. Conclusion:These results suggest that reduction of plasma BDNF level is related to suicidal behavior and BDNF level may be a biological marker of suicidal behavior.

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A Study on the Problems and Improvement of International Factoring System in China (중국 국제팩토링제도의 문제점과 개선방안에 관한 연구)

  • Park, Se Hun;Lee, Gyu Chang;Seo, Kyung
    • THE INTERNATIONAL COMMERCE & LAW REVIEW
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    • v.59
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    • pp.159-178
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    • 2013
  • International factoring is very useful to transfer credit risk, to promote cash flow, to collect debt and to reduce cost and expenses. However, International factoring system in china shows imperfection especially in gap of legal vacuum and its limit to be developed. Here I suggest a practical alternative for development of International factoring system in china as follow. First, legal environment in China for factoring system should be rearranged. Even law and contract law have relative clauses for factoring system there are many difficulty to be applied. It is necessary to prepare legal ground for factoring system. Second, without recourse for International factoring system should be fixed. Without recourse is the essential point for factoring system in international trade. In fact chinese factors are partially applied only for those big global companies. However International factoring system is especially useful for small-medium companies lacked of a good credit rating. It is necessary to promote special factors by combining financial organizations as it does in developed countries. Third, they need to make legal ground to prohibit unlicensed factoring companies. Forth, they need to educate usefulness of factoring system. The settlement system in China is to be developed by systematic researches and promotion for International factoring system.

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Evaluation of Introducing Feasibility of Blockchain Technology to Food Safety Management Network (식품안전관리망 강화를 위한 블록체인 기술 도입의 적절성 평가)

  • Kwon, So-Young;Min, Kyong-Se;Cho, Seung Yong
    • Journal of Food Hygiene and Safety
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    • v.34 no.5
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    • pp.489-494
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    • 2019
  • The appropriateness of introducing blockchain technology into food safety management systems was evaluated by conducting a survey of experts on the effectiveness and constraint evaluation indicators, and a portfolio analysis was conducted to set the priorities of blockchain application. The food safety management activities considered in this study were issuing documents on food import/export, food hygiene rating scheme, civil complaint management in the food sector, food- related certification, risk information management, and food traceability systems. The sectors that can be expected to be effective in the introduction of blockchain technology were food- related certification, food hygiene rating scheme, risk information management, and issuing documents on food import/export. In the case of food traceability systems and civil complaint management, the introduction of blockchain technology was not recommended due to ineffectiveness. From the evaluation of the constraints (e.g., technical limits, cost, legal amendment, personal information disclosure, timeliness, and ease of connection) to be overcome when introducing blockchain into food safety management, it was found that there are more than average constraints in all six areas. In particular, the food traceability system was evaluated to have the most constraints. Issuing documents on food import/export is very effective with the introduction of blockchain technology, but due to high cost and legal restrictions, it is necessary to improve the institutional system in order to introduce blockchain. Among the evaluation sectors, food- related certification, food hygiene rating scheme, and risk information management on foods were suitable for preferentially adopting blockchain technology since these areas might experience greatly improved reliability and transparency through the introduction of blockchain, with relatively low constraints.