• Journal of Chest Surgery
• /
• v.36 no.10
• /
• pp.741-747
• /
• 2003

Background: Coronary artery bypass graf t (CABG) has been settled as most safe surgery among the open heart surgeries. However, in patients with cardiogenic shock, the emergency CABG has higher mortality than elective CABG. We analyzed thirty four patients who underwent emergency CABG and report the middle and long-term results. Material and Method: From June 1994 to December 2001, 34 patients who underwent emergency CABG at Kang-dong Sacred Heart Hospital were include in this study. On the basis of hospital databases and Out Patient Department (OPD) follow up data, preoperative diagnosis, risk factor, coronary artery anatomy, operation technique, postoperative mortality, complication, recurrence of symptom, and mid and long term mortality were analyzed retrospectively. Result: Indications for emergency CABG were 29 cardiogenic shocks (85.3%), 4 intractable chest pains (11.8%), and 1 polymorphic ventricular tachycardia (2.9%). Preoperative angiographic diagnoses were triple vessel disease in 16 (47.1%) and left main disease in 8 (23.5%) patients. We used saphenous vein grafts in 81 and left internal thoracic artery grafts in 14 anastomosis. The mean number of grafts per patients was 2.8$\pm$0.8. The mean aortic cross clamp time was 91.9$\pm$34.6 minutes and the mean cardiopulmonary bypass time was 262.7$\pm$198.3 minutes. Early mortality was 50% and the most common cause of early mortality was low cardiac output in 7 (20.6%) patients. The mean follow-up period was 30.9$\pm$35.7 months. There were no recurrences of symptom and late mortality. Conclusion: In the case of emergency operation, aggressive and proper management with drugs and IABP should be done for preoperative hemodynamic stability and early surgical intervention is the most important factor for patient salvage.

• Journal of radiological science and technology
• /
• v.29 no.3
• /
• pp.167-175
• /
• 2006

With the recent prevalence of helical CT and multi-slice CT, which deliver higher radiation dose than conventional CT due to overbeaming effect in X-ray exposure and interpolation technique in image reconstruction. Although multi-detector and helical CT scanner provide a variety of opportunities for patient dose reduction, the potential risk for high radiation levels in CT examination can't be overemphasized in spite of acquiring more diagnostic information. So much more concerns is necessary about dose characteristics of CT scanner, especially dose efficient design as well as dose modulation software, because dose efficiency built into the scanner's design is probably the most important aspect of successful low dose clinical performance. This study was conducted to evaluate z-axis geometric dose efficiency in single detector CT and each level multi-detector CT, as well as to compare z-axis dose efficiency with change of technical scan parameters such as focal spot size of tube, beam collimation, detector combination, scan mode, pitch size, slice width and interval. The results obtained were as follows ; 1. SDCT was most highest and 4 MDCT was most lowest in z-axis geometric dose efficiency among SDCT, 4, 8, 16, 64 slice MDCT made by GE manufacture. 2. Small focal spot was 0.67-13.62% higher than large focal spot in z-axis geometric dose efficiency at MDCT. 3. Large beam collimation was 3.13-51.52% higher than small beam collimation in z-axis geometric dose efficiency at MDCT. 4. Z-axis geometric dose efficiency was same at 4 slice MDCT in all condition and 8 slice MDCT of large beam collimation with change of detector combination, but was changed irregularly at 8 slice MDCT of small beam collimation and 16 slice MDCT in all condition with change of detector combination. 5. There was no significant difference for z-axis geometric dose efficiency between conventional scan and helical scan, and with change of pitch factor, as well as change of slice width or interval for image reconstruction. As a conclusion, for reduction of patient radiation dose delivered from CT examination we are particularly concerned with dose efficiency of equipment and have to select proper scanning parameters which increase z-axis geometric dose efficiency within the range of preserving optimum clinical information in MDCT examination.

• Journal of Chest Surgery
• /
• v.39 no.5 s.262
• /
• pp.347-353
• /
• 2006

Background: Despite recent advances in surgical technique and perioperative care of total anomalous pulmonary venous return (TAPVR), post-repair pulmonary vein stenosis (PVS) remains as a serious complication. We thought that the most important factors of TAPVR repair to prevent PVS were good exposure, proper alignment, and sufficient stoma size. We analyzed our experience retrospectively. Material and Method: Between Jan. 1995 and Feb. 2005, we studied 74 patients diagnosed with TAPVR suitable for biventricular repair. Supra-cardiac type (n=41, 55.4%) was the most common. Mean CPB time, ACC time, and TCA (40.5%, 30/74) time were $92.1{\pm}25.9\;min,\;39.1{\pm}10.6\;min$, and $30.2{\pm}10.7\;min$, respectively. Mean follow-up duration was $41.4{\pm}29.1$ months and follow-up was possible in all patients. Result: The median age and body weight at operation were 28.5 days ($0{\sim}478$ days) and 3.4 kg $(1.4{\sim}9\;kg)$. Early mortality was 4.1% (3/74). Causes of death were pulmonary hypertensive crisis, sepsis, and sudden death. There was PR-PVS in 2 patients (early: 1, late: 1). Both patients were cardiac type TAPVR drained to coronary sinus. Re-operations were done but only one patient survived. Cumulative survival rate in 5 year and percent freedom from PVS were $94.5{\pm}2.7%\;and\;97.2{\pm}2.0%$, respectively. Conclusion: There was no PVS in patients who underwent extra-cardiac anatomosis between LA and CPVC. Therefore it could be said that our principle might be effective in preventing PR-PVS in patients suitable two-ventricle.

• Journal of Intelligence and Information Systems
• /
• v.17 no.3
• /
• pp.187-201
• /
• 2011

KOSPI200 index is the Korean stock price index consisting of actively traded 200 stocks in the Korean stock market. Its base value of 100 was set on January 3, 1990. The Korea Exchange (KRX) developed derivatives markets on the KOSPI200 index. KOSPI200 index futures market, introduced in 1996, has become one of the most actively traded indexes markets in the world. Traders can make profit by entering a long position on the KOSPI200 index futures contract if the KOSPI200 index will rise in the future. Likewise, they can make profit by entering a short position if the KOSPI200 index will decline in the future. Basically, KOSPI200 index futures trading is a short-term zero-sum game and therefore most futures traders are using technical indicators. Advanced traders make stable profits by using system trading technique, also known as algorithm trading. Algorithm trading uses computer programs for receiving real-time stock market data, analyzing stock price movements with various technical indicators and automatically entering trading orders such as timing, price or quantity of the order without any human intervention. Recent studies have shown the usefulness of artificial intelligent systems in forecasting stock prices or investment risk. KOSPI200 index data is numerical time-series data which is a sequence of data points measured at successive uniform time intervals such as minute, day, week or month. KOSPI200 index futures traders use technical analysis to find out some patterns on the time-series chart. Although there are many technical indicators, their results indicate the market states among bull, bear and flat. Most strategies based on technical analysis are divided into trend following strategy and non-trend following strategy. Both strategies decide the market states based on the patterns of the KOSPI200 index time-series data. This goes well with Markov model (MM). Everybody knows that the next price is upper or lower than the last price or similar to the last price, and knows that the next price is influenced by the last price. However, nobody knows the exact status of the next price whether it goes up or down or flat. So, hidden Markov model (HMM) is better fitted than MM. HMM is divided into discrete HMM (DHMM) and continuous HMM (CHMM). The only difference between DHMM and CHMM is in their representation of state probabilities. DHMM uses discrete probability density function and CHMM uses continuous probability density function such as Gaussian Mixture Model. KOSPI200 index values are real number and these follow a continuous probability density function, so CHMM is proper than DHMM for the KOSPI200 index. In this paper, we present an artificial intelligent trading system based on CHMM for the KOSPI200 index futures system traders. Traders have experienced on technical trading for the KOSPI200 index futures market ever since the introduction of the KOSPI200 index futures market. They have applied many strategies to make profit in trading the KOSPI200 index futures. Some strategies are based on technical indicators such as moving averages or stochastics, and others are based on candlestick patterns such as three outside up, three outside down, harami or doji star. We show a trading system of moving average cross strategy based on CHMM, and we compare it to a traditional algorithmic trading system. We set the parameter values of moving averages at common values used by market practitioners. Empirical results are presented to compare the simulation performance with the traditional algorithmic trading system using long-term daily KOSPI200 index data of more than 20 years. Our suggested trading system shows higher trading performance than naive system trading.

• Journal of Radiation Protection and Research
• /
• v.11 no.2
• /
• pp.114-122
• /
• 1986

At present, the treatments of the radiation-induced diseases are only performing by the palliative treatment technique. Moreover, radiation protective agents are a little toxic for human being and this seriously limits their applicability with various complications in clinical uses. Accordingly, as a part of the aim of gain of the basic data for protective roles of some radioprotectors, the present investigation was carried out to evaluate the comparative radioprotective effects by the administration of DDC, MEA, WR-2721. Results are shown for statistically significant analysis and correlation with each group as follows; 1. The proper doses of the radioprotectors were DDC; 1,550 mg/kg, MEA; 450 mg/kg, WR-2721; 780 mg/kg of the mouse body weight. 2. DMF(Dose modification factor) of LD 50/10 and LD 50/30 for whole body irradiation was DDC; 1.2, MEA; 1.4, WR-2721; 1.9 and DDC; 1.7, MEA; 1.8, WR-2721; 2.5 respectively. 3. DMF for radiation reaction of jejunal crypt was DDC: 1.07, MEA: 1.21 and WR-2721: 1.76 and that of jejunal crypt cell was DDC: 1.04, MEA: 1.08 and WR-2721: 1.38 respectively. 4. Conclusively, WR-2721 was the most effective drung among the three radioprotectors and this result must be a supportive data for further study for clinical application.

• Journal of agricultural medicine and community health
• /
• v.9 no.1
• /
• pp.56-66
• /
• 1984

Giardia lamblia is a pathogenic flagellate causing intestinal disorders such as diarrhea, abdominal pain and malabsorption of nutrients. Giardia is mainly infected by the ingestion of contaminated foods per os. Craun (1979) has recently reported that mass infection of this flagellate through the contaminated water supply systems is one of public health hazards. Also, so-called traveller's diarrhea is sometimes caused by Giardia infection (CDC, U.S.A., 1971). However, a few epidemiological studies figuring out the mode of infection or control measures of Giardia infection has been done so far in Korea. The present study was aimed to know the prevalence of Giardia infection in several Korean populations, detectability of this flagellate in water systems and the viability of the cysts against sewages and disinfectants applying to drinking water. In the present study, 388 stool specimens from orphanage children in Chun-joo, Chung-joo, On-yang and Chun-an areas and 538 stool specimens from inhabitants in Woo-do, In-chon, and Chun-joo were examined by formalin-ether concentration technique to detect out Giardia cysts. On the other hand, water samples from 14 sites of Han River and its tributaries were collected in May through July, 1984. Fifty liter of water sample in each sampling site was then filtered through water filtering system deviced by U.S. Environmental Proutection Agency and the sediments rinsed out from the thread rolls, a part of water filtering system, were examined to detect out the Giardia cysts. In order to observe the viability of Giardia cysts in the sewage samples, the cysts were treated in it at $4^{\circ}C$ or $25^{\circ}C$ for 7 through 28 days. For this purpose, the cysts were also exposed to various concentrations of disinfectants such as chlorine, iodine and ozone gas for proper time intervals. After treatment, the viability test of the Giardia cysts were carried out by method of Rice and Schaefer (1981) with minor modification. The results obtained in this study were as follows : 1) The detection rates of G lamblia cysts in the stool specimens were 18.3% in orphans and 4.3% in general examinees. 2) The prevalences of Giardia Infection were higher in the young age groups than in-adults. The highest positive rate was 18.4% in the age group less than 10. 3) Of 14 water specimens sampled from Han River system and its tributaries around the Seoul area, the Giardia cysts were detected from 4 samples, and no cyst was found in the water supply systems. 4) The cysts treated in the sewage survived for 28 days at $4^{\circ}C$ and for 13 days at $25^{\circ}C$. 5) The cysts were completely destroyed within 60 minutes by exposure to 8 mg/l of residual chlorine at 4g and within 30 minutes by exposure to the same concentration of chlorine at $25^{\circ}C$. 6) The cysts were all dead when exposed to 1 mg/1 of iodine for 60 minutes at $4^{\circ}C$ or $25^{\circ}C$. 7) The cysts were destroyed after 10 minute exposure in 0.15 mg to 0.25mg of residual ozone gas per liter. Summarizing the above results, it is considered that Giardia infection is regarded as water-borne disease and the cysts are able to be controlled by the application with the disinfectants in the water supply systems.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
• /
• v.19 no.3 s.31
• /
• pp.134-145
• /
• 2006

Objective : This study was carried out to investigate what type of assumption and conditions are needed for the application of various statistical techniques such as descriptive statistics, t-test, analysis of variance, correlation analysis, regression analysis and chi-square test and to evaluate that they are used correctly in the research process. Methods : One more methods of statistical analysis were used in 91 papers among 162 papers selected from the journal of Korean oriental medical Ophthalmology & Otolaryngology & Dermatology from April 2003 to December 2005. So we analysed the type of statistical analysis method in 91 papers(clinical and experimental study) and assessed the their validity of statistical techniques by the check list consisting of 34 items(3 items for validity assessment of descriptive statistics, 6 items for t-test, 7 items for analysis of variance, correlation analysis and regression analysis, respectively, 4 items for chi-square test) Results : 1. The type of 65(40%) cases is experimental trial, the type of 55(34%) cases is case report, the type of 26(16%) cases is clinical trial and the type of 16(10%) cases is review, in 91 papers using statistical techniques among 162 papers selected from the journal of Korean oriental medical Ophthalmology & Otolaryngology & Dermatol-ogy from April 2003 to December 2005. 2. One more methods of statistical analysis were used in the experimental and clinical study. When we classified 125 units using statistical analysis methods in 91 papers according to statistical techniques such as descriptive statistics, t-test, analysis of variance, correlation analysis, regression analysis and chi-square test, the number of independent sample t-test is 33(26%), the number of only descriptive statistics is 28(22%), the number of independent sample t-test is 33(26%), the number of only descriptive statistics is 28(22%), the number of one way ANOVA is 15(12%), the number of non-parametric test 10(8%). 3. After carrying out one way ANOVA, the number of using multiple comparison methods is 15(Scheffe:6(26%), Duncan:4(17%), Dunnett:3(13%), Tukey:2(9%)) out of 23 (total case carrying out one way ANOVA). 8(35%) out of 23 did not enforce multiple comparison methods after carrying out one way ANOVA. 4. From the assessment of validity about 63 cases using statistical techniques(except descriptive statistics), 5(8%) cases are proper, the other 58(92%) are improper, so we recognized a serious misuse of statistical application in our journal. 5. The number of case below 10 sample size in experimental and clinical study(except descriptive statistics) is 31(34%) and frequent. Also the number of case containing no mention of sample size is 41(45%, including culture study). 6. For example of statistical error, there are wrong choice of statistical technique, lack of check on standard assumption(such as standard distribution, equivariance, independence), and so on. Conclusions : We investigated the validity of statistical analysis methods in our journal by check list consisting of 34 items and suggested correct statistical analysis methods. We should practice the spread of education about statistical analysis methods and precis application, enhance objectivity and reliability of our thesis and further correspond with purpose of scientific study.

• Journal of Chest Surgery
• /
• v.43 no.3
• /
• pp.254-259
• /
• 2010

Background: Diagnosing chronic pulmonary embolism at an early stage is difficult because of the patient’s nonspecific symptoms. This condition is not prevalent in Korea, and in fact, there have been only a few case reports on this in the Korean medical literature. We analyzed the surgical outcome of performing pulmonary thromboendarterectomy in patients with chronic pulmonary embolism. Material and Method: The study subjects included those patients who underwent surgery for chronic pulmonary embolism from 1996 to 2008. For making the diagnosis, echocardiography, chest CT and a pulmonary perfusion scan were performed on the patients who complained of chronic dyspnea. Result: Pulmonary endarterectomy was performed as follows: by incision via a mid-sternal approach (7 patients); by incision via a left posterolateral approach (1 patient); using the deep hypothermic circulatory arrest technique (4 patients); under ventricular fibrillation (3 patients); and under cardioplegic arrest (1 patient). The postoperative systolic pulmonary artery blood pressure significantly decreased from a preoperative value of $78.9{\pm}14.5\;mmHg$ to $45.6{\pm}17.6\;mmHg$ postoperatively (p=0.000). The degree of tricuspid regurgitation was less than grade II after surgery. Two patients died early on, including one patient who had persistent pulmonary hypertension without improvement and right heart failure. Conclusion: Patients who have chronic pulmonary embolism are known to have a poor prognosis. However, we think that early surgical treatment along with making the proper diagnosis before the aggravation of right heart failure can help improve the quality of a patient's life.

• Culinary science and hospitality research
• /
• v.1
• /
• pp.57-89
• /
• 1995

Despite prologed business stagnation of both international and domestic economy, hotel business as well as tourist industry has continuously been keeping growing, owing to increase of surplus income and world flowing population. During recent 4 years, growth rate of yearly mean in domestic hotels reached 9.9% and especially that of the superior class hotels 15.2%. In the composition of domestic tourist hotel's revenue, the earnings of guest rooms form 37.4%, on the other hand those of food & beverage 39.9%. This result is that our hotel business is concentrated on its interest in FOOD & BEVERAGE of which productivity per unit dimension can be increased to an unlimited extent and extent and superior class hotels strengthened in F&B are increasing in comparison with European or American hotels which are focused on guest rooms in their management. For value added rate of F&B is low as compared with increase of their earnings, they are interested in the management techniques which focus on rising the rate. As for the cost of Food & Beverage, personnel expenditure forms 36.5% and the direct materials 31.5%. Therefore how to manage personnel and materials costs which compose as much as 68% of total revenue will greatly affect net profit. We can say that an effective management technique in cost of Food & Beverage is one of the most important know-hows in hotel management. Especially management know-how for the Kitchen Department where the most of foods come out makes a great effects on various expenses, productivity and it is the achievement from hotel management. For the most of the hotel's top managers, they don't seriously take the fact that KITCHEN SYSTEM affects greatly total expenditure. This study starts from the point of recognizing the question of fundamental cause affecting tow largest cost elements incurred in Food & Beverage and trying to present an effective kitchen system. To settle the questions raised, I compared and analyzed productivity and cost of food & beverage and unit kitchen centered around superior class hotels in Seoul, which vary in Kitchen Systems. In order to attain the aforementioned study effectively purpose of this study, I compared Room-Service and Coffee-Shop Menu, flow of basic food in the kitchen, extent and result of division of labor and integration in the kitchen, scale of outlet kitchen, productivity, the turnover rate of food in store, food cost rate one another which all vary in Kitchen Systems. All these elements are compared and analyzed each other being divided into two main groups such as①. Main Production kitchen and Banquet Kitchen, and ②. coffee-shop kitchen and Room-service Kitchen. Therefore this study is to point out the problems in managing kitchens of superior class hotels which are different in systems. An effort was made to find out the better Kitchen System for superior deluxe hotels. I emphasize the followings on the proper scale of division of labor and integration of unit kitchen and a disposition plan for outlet kitchens of restaurant. First, KITCHEN SYSTEM as a sub-system of Hotel Management System is composed of sub-systems of outlet unit kitchen. Basic food materials are cooked and served for the guests while support kitchen and out restaurant kitchen interact organically each other. So Kitchen should be considered as a system composed of integrated sub-systems. Second, support and banquet kitchens should be integrated to be managed. And these unit kitchens have to be designed to be placed in the back of banquet rooms area. Third, coffee-shop kitchen and room-service kitchen should be integrated to be managed. Fourth, several unit business kitchens should be place on the same floor. Fifth, main production kitchens ought to be located near the loading duck, food store and large refrigerator. Sixth, considering the limits of supervision, duties should be adjusted as 12-20 cooks in two shifts a day for a sub-kitchen, and 18-30 cooks in three shifts a day so that labor division can be made. Last, I would like to two points for direction and task of future study. Firstly, I compare the effective income and increasing costs each other, which are incurred by increasing the use rate of the second processing materials for foods perched outside and through the results. I can find out the better points of the processing production and circulation system, and then I study this effects made on hotel kitchen system. Secondly, I can point out that more efficient kitchen system shall be established through comparing and analyzing the matter of amount of indirect costs and flow of food in different kitchen systems.

• Asia pacific journal of information systems
• /
• v.19 no.2
• /
• pp.157-178
• /
• 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.