• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.21 no.12
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• pp.715-732
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• 2009

This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2008. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) Research trends in thermal and fluid engineering have been surveyed in the categories of general fluid flow, fluid machinery and piping, new and renewable energy, and fire. Well-developed CFD technologies were widely applied in developing facilities and their systems. New research topics include fire, fuel cell, and solar energy. Research was mainly focused on flow distribution and optimization in the fields of fluid machinery and piping. Topics related to the development of fans and compressors had been popular, but were no longer investigated widely. Research papers on micro heat exchangers using nanofluids and micro pumps were also not presented during this period. There were some studies on thermal reliability and performance in the fields of new and renewable energy. Numerical simulations of smoke ventilation and the spread of fire were the main topics in the field of fire. (2) Research works on heat transfer presented in 2008 have been reviewed in the categories of heat transfer characteristics, industrial heat exchangers, and ground heat exchangers. Research on heat transfer characteristics included thermal transport in cryogenic vessels, dish solar collectors, radiative thermal reflectors, variable conductance heat pipes, and flow condensation and evaporation of refrigerants. In the area of industrial heat exchangers, examined are research on micro-channel plate heat exchangers, liquid cooled cold plates, fin-tube heat exchangers, and frost behavior of heat exchanger fins. Measurements on ground thermal conductivity and on the thermal diffusion characteristics of ground heat exchangers were reported. (3) In the field of refrigeration, many studies were presented on simultaneous heating and cooling heat pump systems. Switching between various operation modes and optimizing the refrigerant charge were considered in this research. Studies of heat pump systems using unutilized energy sources such as sewage water and river water were reported. Evaporative cooling was studied both theoretically and experimentally as a potential alternative to the conventional methods. (4) Research papers on building facilities have been reviewed and divided into studies on heat and cold sources, air conditioning and air cleaning, ventilation, automatic control of heat sources with piping systems, and sound reduction in hydraulic turbine dynamo rooms. In particular, considered were efficient and effective uses of energy resulting in reduced environmental pollution and operating costs. (5) In the field of building environments, many studies focused on health and comfort. Ventilation. system performance was considered to be important in improving indoor air conditions. Due to high oil prices, various tests were planned to examine building energy consumption and to cut life cycle costs.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.5 no.1
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• pp.125-141
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• 1998

The purpose of this research is to analyze the effects of aerobic exercise on body composition, cardiopulmonary function, serum lipid level and antioxidants of obese and normal college female students. The subject group was made up of 13 normal students (below 30% body fat ratio) and 12 obese students (above 30% body fat ratio). After a pretest, the subjects were given an 8-week aerobic program. Then the subjects were given a posttest and analyzed of body composition, serum lipid level, antioxidants and cardiopulmonary function after the 6th and the 8th week of the program. The program schedule was made up of 4 days per week, 60 minutes per day. Test includes B.W., subscapular and triceps subcutaneous fat thickness, change of respiratory gas, and two blood sampling before treadmill exercise and post all out state, which analyzed serum lipid and antioxidants. The subjects performed treadmill exercise starting with 4km/hr of walking and then gradually increase the speed of 1km/hr per minute until all out state. The obtained data were analyzed using SAS program. The statistical methods employed here were one-way ANOVA with repeated measure, Duncan Multiple range test, paired-t test and t-test. The test results and conclusion of this research were as follows. 1. The effects of aerobic exercise on body composition were as follows ; Percent body fat was significantly reduced 6 weeks after the program and lean body mass was significantly increased 8 weeks after the program in both groups(obese group: F=3.44 P=.044, normal group: F=3.30 P=.048). subscapular skinfold of the obese group showed a remarkable decrease after the 6th week(F=4.33 P=.021) triceps skinfold of the normal group showed a remarkable decrease after the 6th and the 8th week(F=4.55 P=.017) compared with readings before the aerobic program, the aerobic program made a bigger difference concerning body fat, lean body mass, subscapular skinfold in the obese group than in the normal group(t=2.41 P=.024, t=2.40 p=.025, t=2.43 p=.028). 2. The effects of aerobic exercise on cardiopulmonary function were as follows ; Maximal $O_2$ uptake/kg was significantly increased 6 weeks after the program in the obese group(F=3.20 P=.054), but not much difference was observed in the normal group. Maximal pulse rate was significantly reduced in both groups after 6 weeks of the program(obese group: F=2.77 P=.087, normal group: F=7.17 P=.001). 3. The effects of aerobic exercise on serum lipid level were as follows ; In a resting period, total cholesterol, Triglyceride, and LDL-cholesterol were slightly higher in the obese group than in the normal group, but HDL-cholesterol was higher in the normal group. But, with the aerobic program, total-cholesterol, Triglyceride, LDL-cholesterol were reduced gradually and HDL-choleterol got increased in both groups, but not much change was noticed in the normal group. However, in the obese group, serum HDL-cholesterol level got increased significantly(F=5.12 P=.012). 4. The effects of aerobic exercise in serum antioxidants were as follows ; In a resting period, the obese group's serum Free Radical and GSSG content were higher than the normal group's and the normal group's serum GSH content was higher than the obese group's. After 6 weeks of the aerobic program, Free Radical was reduced significantly in both groups(obese group: F=13.87 P=.000, normal group: F=18.60 P=.000) In the obese group, 8 weeks after the program, GSH was increased significantly(F=13.78, P=.000). In the normal group, 6 weeks after the program, GSH was reduced but increased again after 8 weeks(F=6.07 P=.005). Plasma GSSG was significantly increased after 8 weeks of exercise in both groups(obese group: F=19.75 P=.000, normal group: F=22.42 P=.000,) Compared with readings before the aerobic program, the aerobic program made a bigger difference serum GSH in the normal group than in the obese group(t=3.37 p=.003). As this result shows, it is known that the regular aerobic exercise improves cardiopulmonary function, body composition, serum lipid effectively and through the serum Free Radical reduction and antioxidant system activation, oxidant stress was suppressed. This effect was higher in the obese group than in the normal one. At least 6weeks exercise period need for improvement of body composition, cardiopulmonary function and activation of antioxidant system. This result suggest that improvement of serum lipid profile was needed longer than 8weeks exercise period.

• Journal of Acupuncture Research
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• v.22 no.3
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• pp.253-270
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• 2005

Objective : The purpose of this study is to establish a category for acupuncture therapy by appropriate etiological analysis and differenciation of edema. Methods : We arrange Huang Di Nei Jing and thirty four kinds of literature about edema. Results : 1. The cause of Edema is functional disorder of lung, spleen, kidney, bladder and tri-energizer by six kinds of natural factors, internal injury and loss of nutritions. 2. Edema compartmentalize into the water of five zang organs, several kinds of edema(e,g. 5, 10, 12, 24) and yang & yin edema. 3. An ultimate cause of edema pathogenesis is the disturbance of Qi function in kidney. 4. In view of the results so far achived,'GV26(水淸)' is a vitally important acupoint in acupuncture treatment of edema.'GV26(水淸)' and 'CV9(水分)' are very useful acupoints in moxibustion. 5. In the acupuncture and moxibustion treatment of yang edema, we can use acupoints as like 'GV26(水溝)', 'S36(足三里)', 'B20(脾兪)' and 'SP9(陰陵泉)' by purgation and reduction for expelling wind, reducing fever and eliminating dampness. In an instance of yin edema, we can use acupoints as like 'CV9(水分)' 'S36(足三里)', 'CV6(氣海)', 'B20(脾兪)', 'B23(腎兪)' and 'K3(太谿)' by reinforcement for tonifying spleen yang-middle energizer-, qi-transmission and water promoting.

• Journal of Periodontal and Implant Science
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• v.32 no.1
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• pp.187-198
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• 2002

The ultimate goal of periodontal therapy is the regeneration of periodontal tissue which has been lost due to destructive periodontal disease. To achieve periodontal regeneration, various kinds of methods have been investigated and developed, including guided tissue regeneration and bone graft. Bone graft can be catagorized into autografts, allografts, xenografts, bone substitutes. And materials of all types have different biological activity and the capacity for periodontal regeneration, but ideal graft material has not been developed that fits all the requirement of ideal bone graft material. Recently, bioactive glass that has been utilized in plastic surgery is being investigated for application in dental practice. But, there has not been any long-term assessment of bioactive glass when used in periodontal intrabony defects. The present study evaluates the long-term effects of bioactive glass on the periodontal regeneration in intrabony defects of human and the effect of plaqu control on long term treatment results after dividing patients into those who underwent 3-month regular check-up and those who didn't under go regular check-up The clinical effect on 74sites from 17 infrabony pockets of 11 patients were analyzed 36months after treatment. 51 sites which underwent regular check up were classified as the Follow-up group(F/U group), and 23 sites which did not undergo regular check up were classified as Non Follow-up group(Non F/U group). After comparing the probing depth, attachment loss, bone probing depth before and 36months after treatment, the following results could be concluded. 1. The changes of probing pocket depth showed a statistically significant decrease between after baseline and 36 months after treatment in F/U group(1.79${\pm}$0.68mm) and did no show astatistically significant decrease between after baseline and 36months after treatment in Non F/U group(0.61${\pm}$0.54mm) (P<0.05). 2. The changes of loss of attachment showed a statistically significant decrease between after baseline and 36 months after treatment in F/U group(1.44${\pm}$0.74mm) and did no show astatistically significant decrease between after baseline and 36months after treatment in Non F/U group(1.18${\pm}$1.54) (P<0.05). 3. The changes of bone probing depth showed a statistically significant decrease between after baseline and 36 months after treatment in both F/U(1.35${\pm}$0.28) and Non F/U group(0.78${\pm}$0.55mm) (P<0.05). The results suggest that treatment of infrabony defects with bioactive glass resulted in significan reduction of attachment loss and bone probing depth 36months after the treatment. The use of bioactive glass in infrabony defects, combined with regular check-up and proper plaque control generally shows favorable clinical results. This measn that bioactive glass could be a useful bone substitute.

• Journal of Periodontal and Implant Science
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• v.30 no.4
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• pp.851-870
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• 2000

The major goals of periodontal therapy is the functional regeneration of periodontal supporting structures already destructed by periodontal disease as well as the reduction of signs and symptoms of progressive periodontal disease. There have been many efforts to develop materials and therapeutic methods to promote periodontal wound healing. There have been increasing interest on the chitosan made by chitin. Chitin is second only to cellulose as the most abundant natural biopolymer. It is a structural component of the exoskeleton of invertebrates(e.g., shrimp, crabs, lobsters), of the cell wall of fungi, and of the cuticle of insects. Chitosan is a derivative of chitin made by deacetylation of side chains. Many experiments using chitosan in various animal models have proven its beneficial effects. The aim of this study is to evaluate the osteogenesis of chitosan on the calvarial critical size defect in Sprague Dawley rats. An 8 mm surgical defect was produced with a trephine bur in the area of the midsagittal suture. The rats were divided into two groups: Untreated control group versus experimental group with 50mg of soluble chitosan gel. The animals were sacrificed at 2, 4 and 8 weeks after surgical procedure. The specimens were examined by histologic, histomorphometric and radiodensitometric analyses. The results are as follows: 1. The length of newly formed bone in the defects was $102.91{\pm}25.46{\mu}m$, $219.46{\pm}97.81{\mu}m$ at the 2 weeks, $130.95{\pm}39.24{\mu}m$, $212.39{\pm}89.22{\mu}m$ at the 4 weeks, $181.53{\pm}76.35{\mu}m$ and $257.12{\pm}51.22{\mu}m$ at the 8 weeks in the control group and experimental group respectively. At all periods, the means of experimental group was greater than those of control group. But, there was no statistically significant difference between the two groups. 2. The area of newly formed bone in the defects was $2962.06{\pm}1284.48{\mu}m^2$, $5194.88{\pm}1247.88{\mu}m^2$ at the 2 weeks, $5103.25{\pm}1375.88{\mu}m^2$, $7751.43{\pm}2228.20{\mu}m^2$ at the 4 weeks and $8046.20{\pm}818.99{\mu}m^2$, $15578.57{\pm}5606.55{\mu}m^2$ at the 8 weeks in the control group and experimental group respectively. At all periods, the means of experimental group was greater than those of control group. The experimental group showed statistically significant difference to the control group at the 2 and 8 weeks. 3. The density of newly formed bone in the defects was $14.26{\pm}6.33%$, $27.91{\pm}6.65%$ at the 2 weeks, $20.06{\pm}9.07%$, $27.86{\pm}8.20%$ at the 4 weeks and $22.99{\pm}3.76%$, $32.17{\pm}6.38%$ at the 8 weeks in the control group and experimental group respectively. At all periods, the means of experimental group was greater than those of control group. The experimental group showed statistically significant difference to the control group at the 2 and 8 weeks. These results suggest that the use of chitosan on the calvarial defects in rats has significant effect on the regeneration of bone tissue in itself

• Journal of Periodontal and Implant Science
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• v.35 no.4
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• pp.1019-1037
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• 2005

The major goals of periodontal therapy are the functional regeneration of periodontal supporting structures already destructed by periodontal disease as well as the reduction of signs and symptoms of progressive periodontal disease. There have been many efforts to develop materials and therapeutic methods to promote periodontal wound healing. There have been increasing interest on the chitosan made by chtin. Chitosan is a derivative of chitin made by deacetylation of side chains. Chitosan has been widely studied as bone substitution and membrane material in periodontology. Many experiments using chitosan in various animal models have proven its beneficial effects. Tetracycline has been considered for use in the treatment of chronic periodontal disease and gingivitis. The aim of this study is to evlauate the osteogenesis of tetracycline blended chitosan membranes on the calvarial critical size defect in Sprague Dawley rats. An 8mm surgical defect was produced with a trephine bur in the area of the midsagittal suture. The rats were divided into five groups: Untreated control group versus four experimental group. Four types of membranes were made and comparative study was been done. Two types of non-woven membranes were made by immersing non-woven chitosan into either the tetracycline solution or chitosan-tetracycline solution. Other two types of sponge membranes were fabricated by immersing chitosan sponge into the tetracycline solution, and subsequent freeze-drying. The animals were sacrificed at 2 and 8 weeks after surgical procedure. The specimens were examined by histologic analyses. The results are as follows: 1. Clinically the use of tetracycline blended chitosan membrane showed great healing capacity. 2. The new bone formations of all the experimental group, non-woven and sponge type membranes were greater than those of control group. But, there was no significant difference between the experimental groups. 3. Resorption of chitosan membranes were not shown in any groups at 2 weeks and 8 weeks. These results suggest that the use of tetracycline blended chitosan membrane on the calvarial defects in rats has significant effect on the regeneration of bone tissue in itself. And it implicate that tetracycline blended chitosan membrane might be useful for guided tissue regeneration.

• The Journal of Korean Academy of Prosthodontics
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• v.47 no.4
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• pp.435-444
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• 2009

Statement of problem: The clinical use of electric and electomagnetic fields for fracture healing applications began in the early 1970s. Since then, several technologies have been developed and shown to promote healing of fractures. Developments of these devices have been aided in recent years by basic research and several well controlled clinical trials not only in the medical field but in dentistry. Purpose: The purpose of this study was to compare alveolar bone reduction following immediate implantation using implants onto which magnets were attached in fresh extracted sockets. Material and methods: Four mongrel dogs were involved. Full buccal and lingual mucoperiosteal flaps were elevated and third and fourth premolars of the mandible were removed. Implants with magnets and implants without magnets were installed in the fresh extracted sockets and after 3 months of healing the animals were sacrificed. The mandibles were dissected and each implant sites were sampled and processed for histological examination. Results: The marginal gaps that were present between the implant and walls of the sockets at the implantation stage disappeared in both groups as a result of bone fill and resorption of the bone crest. The buccal bone crests were located apical of its lingual counterparts. At the 12 week interval the mean of marginal bone resorption in the control group was significantly higher than that of the magnet group. The majority of specimens in magnet group presented early bone formation and less resorption of the buccal marginal bone compared to the control group. Conclusion: Within the limitations of this study, it could be concluded that implants with magnets attached in the early stages of implantation may provide more favorable conditions for early bone formation and reduce resorption and remodeling of marginal bone.

• Journal of Gastric Cancer
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• v.5 no.3 s.19
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• pp.174-179
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• 2005

Purpose: The 5-year survival rate is the most useful parameter for evaluating the effect of management on most malignant tumors. Recurrence after a curative resection for gastric cancer occurs mostly within 3 years of the operation, which caused us to evaluate whether a 3-year disease-free survival (3DFS) can be substituted for a 5-year overall survival (5OS). Materials and Methods: We reviewed the medical records of 656 consecutive patients who had undergone a curative resection for gastric cancer To assess whether 3DFS represents 5OS, we used a simple linear regression with survival probability calculated by using the survival function. Results: Recurrence was found in 175 cases during the follow-up periods. The accumulative frequencies of recurrence at postoperative 1 year, 3 years, and 5 years were 46% (81 cases), 89% (156 cases), and 97% (170 cases), respectively. The correlation coefficient (r) and the coefficient of determination $(r^2)$ between 3DFS and 5OS were 0.87 and 0.76, respectively, and the regression equation was $5OS=0.18+(0.80{\times}3DFS)$. The r and $R^2$ according to the type of recurrence were 0.89 and 0.80 in peritoneal seeding, 0.88 and 0.78 in hematogeneous metastasis, and 0.86 and 0.73 in local recurrence, respectively. The r (0.77) and $r^2$ (0.60) were relatively lower in low stages (stage I and II) compared to r (0.88) and $r^2(0.77)$ in high stages (stage III and IV). Conclusion: The 3DFS is an excellent predictor of 5OS. Therefore, if we use the former as the treatment evaluating method, 2-year time reduction in assessing and reporting treatment results is expected.

• Tuberculosis and Respiratory Diseases
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• v.48 no.6
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• pp.887-897
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• 2000

Background : Since the exact pathogenesis of sepsis-induced ARDS has not been elucidated, the mechanisms of enhanced neutrophilic respiratory burst were probed in endotoxin primed neutrophils associated with the roles of phospholipase A2(PLA2), platelet activating factor(PAF) and apoptosis. Methods : In isolated fresh human neutrophils, effects of the inhibition of PLA2 and PAF on the apoptosis were examined by the method of Annexin-FITC/dual PIflow cytometry. The roles of PLA2 and PAF on the neutrophilic respiratory burst were also examined by measuring oxidant generation in cytochrome-c reduction assay. Activities of the PLA2 and lysoPAF acetyltransferase (lysoPAF AT) of the neutrophils were determined to understand the effect of endotoxin on these enzymatic activities which may be related to the neutrophilic respiratory burst and apoptosis. In addition, the role roles of PLA2 and PAF in neutrophilic adhesion to bovine endothelial cells were examined in vitro by neutrophil adhesion assay. To investigate the effect of oxidants on pulmonary surfactant, cytochemical ultrastructural microscopy was performed. To inhibit PLA2 and PAF, non-specific PLA2 inhibitor mepacrine (100 nM) and WEB 2086 (100 nM) or ketotifen fumarate (10 ${\mu}g$/ml) were used respectively in all in vitro experimental sets. WEB 2086 is PAF receptor antagonist, and ketotifen fumarate is a lyso PAF AT inhibitor. Results: The mapacrine treatment, provided and the endotoxin (ETX) treatment, resulted in increased apoptosis of neutrophils (p<0.001) while treatments of WEB 2086 and ketotifen did not. The inhibition of PLA2 and PAF decreased (p<0.001) production of oxidants from PMA-stimulated neutrophils. While endotoxin increased the PLA2 activity of neutrophils (p<0.01), mepacrine supressed (p<0.001) the activity, provided after treatment of ETX. The lyso PAF actyltransferase activity (lyso PAF AT) increased (p<0.01) after treatment of ETX. In contrast, mepacrine, WEB 2086 and ketotifen showed a tendency of decreasing the activity after treatment of ETX. The treatment of ETX incresed (p<0.001) neutrophil adhesion to endothelial cells, which was reversed by inhibition of PLA2 and PAF (p<0.01). The binding of oxidants to pu1monary surfactant was identified histologically. Conclusions : The enhanced neutrophilic respiratory burst by ETX plays a pivotal role in the pathogenesis of ARDS in terms of oxidayive oxidative stress. Increased production of oxidants from neutrophils is mediated by the activations of PLA2 and lyso PAF AT.

• Journal of Intelligence and Information Systems
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• v.16 no.4
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• pp.99-112
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• 2010

Ensemble learning is a method for improving the performance of classification and prediction algorithms. It is a method for finding a highly accurateclassifier on the training set by constructing and combining an ensemble of weak classifiers, each of which needs only to be moderately accurate on the training set. Ensemble learning has received considerable attention from machine learning and artificial intelligence fields because of its remarkable performance improvement and flexible integration with the traditional learning algorithms such as decision tree (DT), neural networks (NN), and SVM, etc. In those researches, all of DT ensemble studies have demonstrated impressive improvements in the generalization behavior of DT, while NN and SVM ensemble studies have not shown remarkable performance as shown in DT ensembles. Recently, several works have reported that the performance of ensemble can be degraded where multiple classifiers of an ensemble are highly correlated with, and thereby result in multicollinearity problem, which leads to performance degradation of the ensemble. They have also proposed the differentiated learning strategies to cope with performance degradation problem. Hansen and Salamon (1990) insisted that it is necessary and sufficient for the performance enhancement of an ensemble that the ensemble should contain diverse classifiers. Breiman (1996) explored that ensemble learning can increase the performance of unstable learning algorithms, but does not show remarkable performance improvement on stable learning algorithms. Unstable learning algorithms such as decision tree learners are sensitive to the change of the training data, and thus small changes in the training data can yield large changes in the generated classifiers. Therefore, ensemble with unstable learning algorithms can guarantee some diversity among the classifiers. To the contrary, stable learning algorithms such as NN and SVM generate similar classifiers in spite of small changes of the training data, and thus the correlation among the resulting classifiers is very high. This high correlation results in multicollinearity problem, which leads to performance degradation of the ensemble. Kim,s work (2009) showedthe performance comparison in bankruptcy prediction on Korea firms using tradition prediction algorithms such as NN, DT, and SVM. It reports that stable learning algorithms such as NN and SVM have higher predictability than the unstable DT. Meanwhile, with respect to their ensemble learning, DT ensemble shows the more improved performance than NN and SVM ensemble. Further analysis with variance inflation factor (VIF) analysis empirically proves that performance degradation of ensemble is due to multicollinearity problem. It also proposes that optimization of ensemble is needed to cope with such a problem. This paper proposes a hybrid system for coverage optimization of NN ensemble (CO-NN) in order to improve the performance of NN ensemble. Coverage optimization is a technique of choosing a sub-ensemble from an original ensemble to guarantee the diversity of classifiers in coverage optimization process. CO-NN uses GA which has been widely used for various optimization problems to deal with the coverage optimization problem. The GA chromosomes for the coverage optimization are encoded into binary strings, each bit of which indicates individual classifier. The fitness function is defined as maximization of error reduction and a constraint of variance inflation factor (VIF), which is one of the generally used methods to measure multicollinearity, is added to insure the diversity of classifiers by removing high correlation among the classifiers. We use Microsoft Excel and the GAs software package called Evolver. Experiments on company failure prediction have shown that CO-NN is effectively applied in the stable performance enhancement of NNensembles through the choice of classifiers by considering the correlations of the ensemble. The classifiers which have the potential multicollinearity problem are removed by the coverage optimization process of CO-NN and thereby CO-NN has shown higher performance than a single NN classifier and NN ensemble at 1% significance level, and DT ensemble at 5% significance level. However, there remain further research issues. First, decision optimization process to find optimal combination function should be considered in further research. Secondly, various learning strategies to deal with data noise should be introduced in more advanced further researches in the future.