• 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.

• Asia pacific journal of information systems
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• v.18 no.1
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• pp.97-115
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• 2008

Introduction The e-government is concerned with using Internet and Web technologies to exchange information and services with citizens, businesses and other related organizations, and it centers on three functions, namely informational, interactive, and transactional [UN, 2001]. Many developed countries like the U.S. have been actively involved in e-government projects, since they enable both more effective public services for citizens and more efficient internal operations. Korea is among these leading countries that are planning to leverage computer and communication technologies to provide for integration of work processes and information as well as convenient access to information and services. For this reason, evaluating e-government projects is becoming a crucial issue for both researchers and policy-makers. However, most research to date has primarily focused on a model of success of an e-government system designed for citizens, overlooking internal systems specifically created for employees working in a public organization. This paper is intended to propose a model to measure the success of a Web-based information system designed for use by internal users at Chungwadae, the executive branch of Korea's central government. The paper is also aimed at applying the model to the assessment of the present system being used at Chungwadae in comparison with the preceding system. Evaluating an e-Government System The most widely cited model of information systems success today is that of DeLone and McLean[1992, 2003, 2004]. The original model states that the success of an information system can be measured using six dimensions, including system quality, information quality, use, user satisfaction, individual impact, and organizational impact. Although the ultimate success of an information system may be reflected in the impact that the system has upon individuals as well as an organization, aspects of using the system such as system use and user satisfaction can play an important role in determining the system success, because the system would be a sheer failure if users don't like and use the system. As a response to criticisms given by numerous researchers, the authors adapted their model to fit the emerging Web-based environment. The revised model[DeLone and McLean, 2003] they offered included an additional quality dimension, namely service quality, and combined individual and organizational impacts into net benefits which can also influence user satisfaction. The e-government system success model can be built around this updated model. Our model incorporates information quality, system quality, and service quality as in the DeLone and McLean model. However, the 'system use' dimension has been replaced by perceived usefulness, as suggested by Seddon[1998]. In addition, because the e-government systems that this paper focuses on are internal public systems used in government agencies, the 'net benefits' dimension has been replaced by perceived work efficiency. Based on the proposed model, a total of nine hypotheses have been formulated which we tested using an empirical analysis. Methods A questionnaire form has been created with items that are designed to examine the relationships among the variables in the model. The questionnaire has been handed over, in person, to 65 members of Chungwadae staff who are now actively using the E-Support System, the present information system created to support internal work at Chungwadae. We made arrangements to meet with each individual who agreed to participate in our survey, and helped to fill out the survey form with explanations. Of the 65 copies that were delivered, only 33 were returned, and 30 responses of these have been adopted for our analysis, since three were not valid. The extremely small sample size was due to the limited number of staff members who had adequate experience required of this study. Results We gathered data from the questionnaire survey and analyzed them using a regression analysis to test the hypotheses. As shown in the table below, the results indicated that all three dimensions of an information system’s quality are positively related to user satisfaction. However, information quality and system quality were found to be positively related to perceived usefulness, while service quality was not. In addition, perceived usefulness is not positively related to user satisfaction, implying that a user may find a system useful, but may not be satisfied with it. Finally, user satisfaction and perceived usefulness both are positively related to perceived work efficiency. This suggests that workers' positive experience with the system is important to guarantee favorable work efficiency. Conclusions We conclude that the proposed model proved useful in measuring the success of an internal information system used by a government agency. To demonstrate the applicability and usefulness of the model in the paper, we applied the model to the assessment of the present internal system used at Chungwadae in comparison with the preceding system. The results showed that the present system outperforms the preceding one in a statistically significant way. Future research will have to focus on applying the model to Korea's governmental agencies other than Chungwadae and examine whether it proves applicable in different types of governmental organizations.

• Journal of Chest Surgery
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• v.36 no.2
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• pp.73-78
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• 2003

The Fontan operation has undergone a number of major modifications and clinical results have been improving over time. Nevertheless, during the follow-up period, life-threatening complications develop and affect the long-term outcomes. Surgical interventions for these complications are needed and are increasing. Material and Method: From April 1988 to January 2000, 16 patients underwent reoperations for complications after Fontan operation. The mean age at reoperation was 8.8 :-5.5 years. Initial Fontan operations were atriopulmonary connections in 8 and total cavopulmonary connections in 8. Total cavopulmonary connections were accomplished with intracardiac lateral tunnel in 5 and extracardiac epicardial lateral tunnel in 3. Five patients had variable sized fenestrations. The reasons for reoperations included residual shunt in 6, pulmonary venous obstruction in 3, atrial flutter in 3, atrioventricular valve regurgitation in 2, Fontan pathway stenosis in 1, and protein-losing enteropathy in 1 Result: There were 3 early and late deaths respectively Patients who had residual shunts underwent primary closure of shunt site (n=2), atrial reseptation for separation between systemic and pulmonary vein (n=2), conversion to lateral tunnel (n=1), and conversion to one and a half ventricular repair (n=1). Four patients who had stenotic lesion of pulmonary vein or Fontan pathway underwent widening of the lesion (n=3) and left pneumonectomy (n=1) In cases of atrial flutter, conversion to lateral tunnel after revision of atriopulmonary connections was performed (n=3). For the atrioventricular valve regurgitation (n=2), we performed a replacement with mechanical valve. In one patient who had developed protein-losing enteropathy, aorto-pulmonary collateral arteries were obliterated via thoracotomy. Cryoablation was performed concomitantly in 4 patients as an additional treatment modality of atrial arrhythmia. Conclusion: Complications after Fontan operation are difficult to manage and have a considerable morbidity and mortality. However, more accurate understanding of Fontan physiology and technical advancement increased the possibility of treatment for such complications as well as Fontan operation itself. Appropriate surgical treatment for these patients relieved the symptoms and improved the functional class, Although the results were not satisfactory enough in all patients.

• Journal of Chest Surgery
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• v.37 no.1
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• pp.1-10
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• 2004

Background: Currently, the cardiopulmonary machine with non-pulsatile pumps, which are low in internal circuit pressure and cause little damage to blood cells, is widely used. However, a great number of experimental studies shows that pulsatile perfusions are more useful than non-pulsatile counterparts in many areas, such as homodynamic, metabolism, organ functions, and micro-circulation. Yet, many concerns relating to pulsatile cardiopulmonary machines, such as high internal circuit pressure and blood cell damage, have long hindered the development of pulsatile cardiopulmonary machines. Against this backdrop, this study focuses on the safety and effectiveness of the pulsatile cardiopulmonary machines developed by a domestic research lab. Material and Method: The dual-pulsatile cardiopulmonary bypass experiment with total extracorporeal circulation was conducted on six calves, Extracorporeal circulation was provided between superior/inferior vena cava and aorta. The membrane oxygenator, which was placed between the left and right pumps, was used for blood oxygenation. Circulation took four hours. Arterial blood gas analysis and blood tests were also conducted. Plasma hemoglobin levels were calculated, while pulse pressure and internal circuit pressure were carefully observed. Measurement was taken five times; once before the operation of the cardiopulmonary bypass, and after its operation it was taken every hour for four hours. Result: Through the arterial blood gas analysis, PCO2 and pH remained within normal levels. PO2 in arterial blood showed enough oxygenation of over 100 mmHg. The level of plasma hemoglobin, which had total cardiopulmonary circulation, steadily increased to 15.87 $\pm$ 5.63 after four hours passed, but remained below 20 mg/㎗. There was no obvious abnormal findings in blood test. Systolic blood pressure which was at 97.5$\pm$5.7 mmHg during the pre-circulation contraction period, was maintained over 100 mmHg as time passed. Moreover, diastolic blood pressure was 72.2 $\pm$ 7.7 mmHg during the expansion period and well kept at the appropriate level with time passing by. Average blood pressure which was 83$\pm$9.2 mmHg before circulation, increased as time passed, while pump flow was maintained over 3.3 L/min. Blood pressure fluctuation during total extracorporeal circulation showed a similar level of arterial blood pressure of pre-circulation heart. Conclusion: In the experiment mentioned above, pulsatile cardiopulmonary machines using the doual-pulsatile structure provided effective pulsatile blood flow with little damage in blood cells, showing excellence in the aspects of hematology and hemodynamic. Therefore, it is expected that the pulsatile cardiopulmonary machine, if it becomes a standard cardiopulmonary machine in all heart operations, will provide stable blood flow to end-organs.

• Journal of Gastric Cancer
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• v.6 no.4
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• pp.257-262
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• 2006

Purpose: We analyzed the clinicopathologic features, including treatment and outcome, and the survival rates between young and elderly patients with gastric cancer. Materials and Methods: Clinical information was reviewed for 1086 patients who had undergone a gastrectomy for gastric cancer during a 10-year period from 1990 to 1999, and the patients were assigned to one of two groups: the A group (<40 years of age, 91 patients) and the B group (${\geq}70\;years\;of\;age,\;85\;patients)$). Results: Compared to the B group, the A group had more females (47.3% vs 32.9%), a greater frequency of family history of cancer (15.4% vs 3.5%), and greater proportions of histologically poorly differentiated tumors (84.5% vs 40.2%) and Lauren diffuse-type tumors (69.1% vs 35.1%)(P<0.05). There was no difference in TNM stage. Cardiopulmonary co-morbidities were more in the B group, respectively, 1.1% (A group) and 11.8% (B group)(P<0.01), but the morbidity and the mortality were similar. Although there was no difference in curability, the B group underwent less aggressive operations in lymph-node dissection above D3 and had a shorter operation time, a smaller number of retrieved lymph nodes, and less adjuvant chemotherapy (P<0.001). However, there were no differences in the disease-specific 5-year survival rates, 67.6% and 67.0% respectively. Conclusion: Young and elderly patients with gastric cancer had different clinicopathological features. Especially, elderly patients underwent relatively less aggressive treatment. In spite of these facts, the outcome of treatment and the disease-specific survival rates were not different.

• Journal of Gastric Cancer
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• v.8 no.4
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• pp.256-261
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• 2008

Purpose: Intra-abdominal fluid collection is one of the risk factors associated with postoperative morbidity or mortality for patients who undergo gastric cancer surgery. The aim of this study was to analyze the clinicopathological characteristics of the patients with postoperative intra-abdominal fluid collection and to identify the indications for inserting a percutaneous drain (PCD) in patients with intra-abdominal fluid collection. Materials and Methods: Among the 1,277 patients who underwent operations for gastric cancer at Seoul National University Hospital between April 2005 and July 2006, the data of 117 patients with an intra-abdominal fluid collection were reviewed. Results: The number of patients' with pathologic stage I, II, III and IV disease was 42 (36.8%), 23 (20.2%), 16 (14%) and 33 (28.9%), respectively. Forty-three patients (36.3%) underwent PCD insertion and the other 43 patients received conservative management. A univariate analysis of multiple clinical variables revealed that age, gender, diabetes, liver disease, lymph node dissection, the pathologic stage and the body mass index (BMI, $kg/m^2$) were not significantly associated with PCD insertion (P>0.05). However, the univariate analysis showed that two characteristics were associated with a significantly high incidence of PCD insertion: a diameter of an intra-abdominal fluid collection greater than 4 cm and infectious signs such as leukocytosis, fever and bacteremia. Conclusion: About two thirds of the intra-abdominal fluid collections after surgery for gastric cancer were managed with only conservative method without other morbidities of mortality. Surgeons should consider performing PCD insertion if the largest diameter of an intra-abdominal fluid collection is over 4 cm or if infectious signs are seen.

• Journal of Chest Surgery
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• v.32 no.3
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• pp.294-298
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• 1999

Background: Video-assisted thoracoscopic surgery(VATS) has been established as a new method for treatment of spontaneous pneumothorax. We compared the clinical results of VATS with those of thoracotomy performed during the recent 5 years. Material and Method: We analyzed 126 patients whose medical records were available among the 154 patients who underwent operations for spontaneous pneumothorax from 1992 to 1996. The mean age was 27.1 years(15 to 75 years). 87 patients were operated on by VATS(Group A) and the other 39 by thoracotomy(Group B). The mean follow-up period was 14.7 months. Result: The operation time was shorter in group A than in group B(90.6${\pm}$38.6minutes: 117.2${\pm}$58.9minutes, p<0.05). The duration of postoperative hospital stay was shorter in group A than in group B(6.7${\pm}$4.2: 9.4${\pm}$3.3 days, p<0.05). The amount of analgesics(nalbuphin HCl, ketoprofen) used postoperatively were 2.4${\pm}$2.8 ampules in group A, which is less than the 6.5${\pm}$5.6 ampules in group B(p<0.05). The number of staples used in group A was smaller(2.7${\pm}$1.3 in group A, 1.76${\pm}$1.1 in group B, p<0.05). The duration of chest tube indwelling(4.3${\pm}$4.0 days in group A, and 5.6${\pm}$3.0 days in group B, NS), the recurrence rate(13.8% in group A, 2.6% in group B, NS), and the duration of air leakage(1.3${\pm}$3.3 days in group A, and 1.0${\pm}$2.5days in group B, NS) were not statistically different between the two groups. Conclusion: The application of VATS for the treatment of spontaneous pneumothorax has brought in better clinical results(shorter operation time, shorter hospital stay, less pain, and better cosmetic merits) than the thoracotomy without increasing any morbidity. However no advantages in recurrence rates and duration of postoperative air leakages are revealed.

• Korean Journal of Environmental Biology
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• v.38 no.4
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• pp.733-743
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• 2020

We estimated the carbon storage of coal mines reclaimed using Betula platyphylla (BP), Pinus koraiensis (PK), and Pinus spp. (PS, Pinus densiflora, Pinus rigida, and Pinus thunbergii). The carbon storage of tree biomass (TB), forest floor(FF), mineral soil (MS), and the total forest were quantified. Reclaimed sites were located in Gangwon-do, Gyeongsangbuk-do, and Jeollanam-do; reclamation was conducted at various times in each region. The carbon storage (ton C ha^-1) in FF (BP: 3.31±0.59, PK: 3.60±0.93, PS: 4.65±0.92), MS (BP: 28.62±2.86, PK: 22.26±5.72, PS: 19.95±3.90), and the total forest(BP: 54.81±7.22, PK: 47.29±8.97, PS: 45.50±6.31) were lower than that of natural forests (NF). The carbon storage in TB was lower in BP (22.57±6.18) compared to NF, while those in PK(21.17±8.76) and PS (20.80±6.40) were higher than in NF. While there were no significant differences in the carbon storage of TB, FF, and the total forest among tree species, results from MS showed a significant difference among species. TB and the total forest carbon storages in all sites increased after reclamation. Soil pH and cation exchange capacity values in BP and PS were lower than in NF. Amounts of labile carbon, available phosphate, and microbial biomass carbon in reclaimed sites were less than half of NF. There are a number of methods that could increase the reclamation efficiency. Applications of lime or organic fertilizers, as well as tillage operations, may improve soil properties in reclaimed coal mines. Additionally, pruning and thinning would increase tree growth thereby increasing carbon storage.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.4
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• pp.527-536
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• 2022

The purpose of this study is to predict changing traffic environments and related economic effects by reflecting the changed KTDB and socio-economic indicators pertaining to Mulgeum station, a general railway stop, when it is confirmed as a KTX stop. To analyze the data of this study, socioeconomic indicators and the general status of transportation facility operations were investigated with reference to related statistical data, centered on the country overall and on Yangsan city in particular. In addition, we investigated and referenced the railroad facility construction plan and train operation plan, which are national high-level plans related to land development and transportation network construction. Currently, there are only ITX trains (4 times/day) and Mugunghwa trains (29 times/day) that stop at Mulgeum station in Yangsan, meaning that passengers cannot use KTX trains in the Yangsan area. In particular, the need for a KTX stop at Mulgeum station has been continuously raised because train users in the Yangsan area have inconvenient transportation in that they must travel 40 minutes to Ulsan station or 30 minutes to Gupo station to use the KTX. As a result of analyzing railroad transportation demand that will change in the future as the KTX stop at Mulgeum station is confirmed, the number of passengers boarding and arriving at Mulgeum station is predicted to be 1,674 passengers/day by 2025. In addition, the numbers of train passengers that are converted from Ulsan and Gupo stations due to the stop at Mulgeum station are predicted to be 594 passengers/day boarding and 562 passengers/day arriving by 2025. In the future, if Yangsan citizens use the KTX Mulgeum station, the access time to Mulgeum station can be shortened to 22 minutes from 65 minutes, and it is predicted that the inconvenience of transferring between railroads will be resolved, with the waiting time for transfers reduced by up to a maximum of 40 minutes. Therefore, the economic effect of creating a KTX stop at Mulgeum station was analyzed to be B/C=1.823 when general railroad operating costs are not taken into account and B/C=2.127 when general railroad operating costs are considered. In conclusion, when using KTX trains to visit the Seoul Metropolitan Area, it takes 2 hours and 43 minutes to use Mulgeum station without using Ulsan station or Gupo station, which is considered to be very effective for reducing travel times and improving the economic feasibility of this development; it is also expected that Yangsan city will be able to improve accessibility and mobility to the Seoul Metropolitan Area by breaking free from the disgrace of being a remote location given its link to KTX in the future.

• The Korean Society of Law and Medicine
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• v.22 no.2
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• pp.111-138
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• 2021

'Unlicensed medical practice by a non-medical practitioner' often represented by surrogate surgery or so-called 'ghost surgery,' causes irreparable damage to life or body, and therefore calls for very strict and effective controls. The 'bill on installment of CCTVs in an operating room' to prevent unlicensed surrogate surgery has been discussed for a long time, but due to numerous issues and heated confrontations, it has been pending in the National Assembly. Nevertheless, it is expected that the bill will be discussed again in earnest in the National Assembly because surrogate surgery and factory-type cosmetic surgery, which has been performed mainly in the field of cosmetic surgery, has also been occurring in the field of therapeutic surgery. In general, an operating room is considered as being locked or closed, as well as disallowing implicit complicity among insiders. Hence, if the insiders conspire to commit or cover up an illegal act, or if a surgeon performs rapid cosmetic surgery and then leaves the recipient (or medical institution) so as to perform more operations for profit - even if it is legitimate practice - it may result in serious consequences in terms of the recovery of a patient. In this case, installation of CCTVs can be of great help in identifying an illegal act and assessing any occurrence of negligence. On the other hand, while the fundamental purpose of therapeutic surgery is to restore a patient's life or body - that is, lifesaving - installation of CCTVs may base the relationship between a surgeon and a patient on distrust and surveillance, so it may increase the number of requests for CCTV footage or lead to more disputes, as well as placing a burden on the surgeon when best results are not achieved for a patient. As a result, the surgeon may choose non-invasive treatment contrary to conscience instead of risky but necessary surgery, or he/she may have significant difficulty in determining the timing of surgery, which may limit the provision of effective surgical medical care. Then, in terms of the relationship between a surgeon and patient, and in the long run, there could be significant disadvantages for the public and patients if CCTV footage is allowed. In this paper, we review domestic and overseas cases and issues regarding installation of CCTVs in an operating room, and present various viewpoints and suggestions to promote legislation with minimized legal problems and side effects, thereby contributing to protection of the lives and health of the public, patients, and recipients of surgery.