• Journal of Intelligence and Information Systems
• /
• v.17 no.3
• /
• pp.25-41
• /
• 2011

Recently, support vector machines (SVMs) are being recognized as competitive tools as compared with other data mining techniques for solving pattern recognition or classification decision problems. Furthermore, many researches, in particular, have proved them more powerful than traditional artificial neural networks (ANNs) (Amendolia et al., 2003; Huang et al., 2004, Huang et al., 2005; Tay and Cao, 2001; Min and Lee, 2005; Shin et al., 2005; Kim, 2003).The classification decision, such as a binary or multi-class decision problem, used by any classifier, i.e. data mining techniques is so cost-sensitive particularly in financial classification problems such as the credit ratings that if the credit ratings are misclassified, a terrible economic loss for investors or financial decision makers may happen. Therefore, it is necessary to convert the outputs of the classifier into wellcalibrated posterior probabilities-based multiclass credit ratings according to the bankruptcy probabilities. However, SVMs basically do not provide such probabilities. So it required to use any method to create the probabilities (Platt, 1999; Drish, 2001). This paper applied AdaBoost algorithm-based support vector machines (SVMs) into a bankruptcy prediction as a binary classification problem for the IT companies in Korea and then performed the multi-class credit ratings of the companies by making a normal distribution shape of posterior bankruptcy probabilities from the loss functions extracted from the SVMs. Our proposed approach also showed that their methods can minimize the misclassification problems by adjusting the credit grade interval ranges on condition that each credit grade for credit loan borrowers has its own credit risk, i.e. bankruptcy probability.

• Journal of Korean Society of Transportation
• /
• v.22 no.1 s.72
• /
• pp.43-62
• /
• 2004

Conventionally the estimation method of the origin-destination Matrix has been developed by implementing the expansion of sampled data obtained from roadside interview and household travel survey. In the survey process, the bigger the sample size is, the higher the level of limitation, due to taking time for an error test for a cost and a time. Estimating the O-D matrix from observed traffic count data has been applied as methods of over-coming this limitation, and a gradient model is known as one of the most popular techniques. However, in case of the gradient model, although it may be capable of minimizing the error between the observed and estimated traffic volumes, a prior O-D matrix structure cannot maintained exactly. That is to say, unwanted changes may be occurred. For this reason, this study adopts a conjugate gradient algorithm to take into account two factors: estimation of the O-D matrix from the conjugate gradient algorithm while reflecting the prior O-D matrix structure maintained. This development of the O-D matrix estimation model is to minimize the error between observed and estimated traffic volumes. This study validates the model using the simple network, and then applies it to a large scale network. There are several findings through the tests. First, as the consequence of consistency, it is apparent that the upper level of this model plays a key role by the internal relationship with lower level. Secondly, as the respect of estimation precision, the estimation error is lied within the tolerance interval. Furthermore, the structure of the estimated O-D matrix has not changed too much, and even still has conserved some attributes.

• The korean journal of orthodontics
• /
• v.29 no.1 s.72
• /
• pp.51-72
• /
• 1999

In orthodontic field, it is very important to understand the normal growth. Such an understanding can be derived from observation of normal growth in various samples from childhood to adulthood, and this builds a foundation from which growth abnormality or variation can be defined. Thus, a broad data collection of normal children, as well as basic study reviewing such data become necessary. The relationship between the mean values of cephalometric measurements in Growth and Development was studied among the groups(boys and girls) of Korean chidren from the ages 6-years to 16-years. 220 boys 170 girls were chosen as subjects : Cephalometric X-ray were taken for 3 years and hard tissue analysis on McNamara and Ricketts Analysis which was divided into measurements of 5 parts(Cranial base, Cranial base and Maxilla & Mandible, Maxilla and Mandible, Mandible, Dental measurements). The relationship of craniofacial growth was studied. The following conclusions were obtained: 1. There were statistically significant differences in anterior cranial base between the two sexes of 14 and 15-year grouips. 2. In comparison of growth amounts among different age groups, statistically singnificant difference in Posterior facial height exhisted among $10\~11,\;12\~13\;and\;14\~15$ year-old interval groups. This pattern increased with aging. 3. Na perpendicular to A showed earlier growth peak in females(11-12years) than males(12-13years). When horizontal measurements of point A and Pogonion are compared, mandibular growth appeared to be greater. 4. Maximum growth peak of cranial base and mandible was earlier in females (11-12years) than males(13-14 years). 5. Upper central incisor flared out with aging, and there were increases in lower incisor to A-Pg, and lower incisor inclination There was significant difference between the two sexes in 10-year-old group.

• Korean Journal of Ichthyology
• /
• v.19 no.1
• /
• pp.1-7
• /
• 2007

The effect of water temperature (T) and body weight (W) on the oxygen consumption of the fasted black rockfish, Sebastes schlegeli was investigated to provide empirical data for the culture management and bioenergetic growth model of this species. The mean wet body weights of two fish groups used for the present experiment were $12.9{\pm}2.7g$ ($mean{\pm}SD$) and $351.1{\pm}9.2g$. The oxygen consumption rate (OCR) was measured under three water temperature regimes (15, 20 and $25^{\circ}C$) at an interval of 5 minutes for 24 hours using a continuous flow-through respirometer. In each treatment three replicates were set up and 45 fish in small size groups and 6 fish in large size groups were used. The OCRs increased with increasing water temperature in both size groups (p<0.001). Mean OCRs at 15, 20 and $25^{\circ}C$ were 414.2, 691.5 and $843.8mg\;O_2\;kg^{-1}h^{-1}$ in small size groups, and 182.0, 250.7 and $328.2mg\;O_2\;kg^{-1}h^{-1}$ in large size groups, respectively. The OCRs decreased with increasing body weights in three water temperature groups (p<0.001). The mass effect on metabolic rate can be expressed by the power of 0.69~0.75. The data are best described by the relationship: OCR=89.12+28.79T-1.17W. $Q_{10}$ values ranged 1.90~2.79 between 15 and $20^{\circ}C$, 1.49~1.71 between 20 and $25^{\circ}C$, and 1.80~2.03 over the full temperature range, respectively. The energy loss by metabolic cost increased with increasing water temperature and decreasing body weight (p<0.001). Mean energy loss rates by oxygen consumption at 15, 20 and $25^{\circ}C$ were 282.9, 472.3 and $576.3kJ\;kg^{-1}d^{-1}$ in small size groups and 124.3, 171.3 and $224.1kJ\;kg^{-1}d^{-1}$ in large size groups, respectively.

• Journal of dental hygiene science
• /
• v.16 no.3
• /
• pp.217-224
• /
• 2016

The aim of this study was to evaluate whether the number of existing permanent teeth is associated with chronic obstructive pulmonary disease (COPD) in a representative sample of Korean adults. Data from 3,107 subjects who participated in the 2009 Korea National Health and Nutrition Examination Survey were examined. The dependent variable was COPD and the independent variable was the number of existing permanent teeth. Spirometry results were classified into three groups (normal pattern, restrictive pattern, and obstructive pattern) by trained technicians. We used dichotomized COPD variables (no vs. yes). The number of existing permanent teeth was evaluated by oral examination and divided into 3 groups (0~19, 20~27, and 28). Demographic factors (age group and sex group), socioeconomic status (education and income), health behaviors (smoking and drinking), oral health and behavior (frequency of toothbrushing; periodontitis; decayed, missing, filled, permanent teeth index; and denture status), and general health status (body mass index, diabetes mellitus, and hypertension) were included as confounders in the analysis. Bivariate analysis and multivariate logistic regression analyses including confounders were applied, and all analyses considered a complex sampling design. Stratified analysis was performed by smoking status. After controlling for various confounders, there was a significant association between the number of existing permanent teeth and COPD (odds ratio [OR], 1.90; 95% confidence interval [CI], 1.20~3.00 for the 20~27 group; OR, 3.93; 95% CI, 1.75~8.84 for the 0~19 group). The association was more significant in current smokers (OR, 8.90; 95% CI, 2.53~31.33). Our data indicate that the number of existing permanent teeth was independently associated with COPD, especially in current smokers. Further longitudinal research is needed to determine whether oral health promotion plays a role in the improvement of lung function and prevention of COPD.

• The Journal of Korean Academy of Prosthodontics
• /
• v.39 no.6
• /
• pp.709-734
• /
• 2001

The aims of this experiment were to investigate the strain and temperature changes simultaneously within autopolymerzing acrylic resin specimens. A computerized data acquisition system with an electrical resistance strain gauge and a thermocouple was used over time periods up to 180 minutes. The overall strain kinetics, the effects of stress relaxation and additional heat supply during the polymerization were evaluated. Stone mold replicas with an inner butt-joint rectangular cavity ($40.0{\times}25.0mm$, 5.0mm in depth) were duplicated from a brass master mold. A strain gauge (AE-11-S50N-120-EC, CAS Inc., Korea) and a thermocouple were installed within the cavity, which had been connected to a personal computer and a precision signal conditioning amplifier (DA1600 Dynamic Strain Amplifier, CAS Inc., Korea) so that real-time recordings of both polymerization-induced strain and temperature changes were performed. After each of fresh resin mixture was poured into the mold replica, data recording was done up to 180 minutes with three-second interval. Each of two poly(methyl methacrylate) products (Duralay, Vertex) and a vinyl ethyl methacrylate product (Snap) was examined repeatedly ten times. Additionally, removal procedures were done after 15, 30 and 60 minutes from the start of mixing to evaluate the effect of stress relaxation after deflasking. Six specimens for each of nine conditions were examined. After removal from the mold, the specimen continued bench-curing up to 180 minutes. Using a waterbath (Hanau Junior Curing Unit, Model No.76-0, Teledyne Hanau, New York, U.S.A.) with its temperature control maintained at $50^{\circ}C$, heat-soaking procedures with two different durations (15 and 45 minutes) were done to evaluate the effect of additional heat supply on the strain and temperature changes within the specimen during the polymerization. Five specimens for each of six conditions were examined. Within the parameters of this study the following results were drawn: 1. The mean shrinkage strains reached $-3095{\mu}{\epsilon},\;-1796{\mu}{\epsilon}$ and $-2959{\mu}{\epsilon}$ for Duralay, Snap and Vertex, respectively. The mean maximum temperature rise reached $56.7^{\circ}C,\;41.3^{\circ}C$ and $56.1^{\circ}C$ for Duralay, Snap, and Vertex, respectively. A vinyl ethyl methacrylate product (Snap) showed significantly less polymerization shrinkage strain (p<0.01) and significantly lower maximum temperature rise (p<0.01) than the other two poly(methyl methacrylate) products (Duralay, Vertex). 2. Mean maximum shrinkage rate for each resin was calculated to $-31.8{\mu}{\epsilon}/sec,\;-15.9{\mu}{\epsilon}/sec$ and $-31.8{\mu}{\epsilon}/sec$ for Duralay, Snap and Vertex, respectively. Snap showed significantly lower maximum shrinkage rate than Duralay and Vertex (p<0.01). 3. From the second experiment, some expansion was observed immediately after removal of specimen from the mold, and the amount of expansion increased as the removal time was delayed. For each removal time, Snap showed significantly less strain changes than the other two poly(methyl methacrylate) products (p<0.05). 4. During the external heat supply for the resins, higher maximum temperature rises were found. Meanwhile, the maximum shrinkage rates were not different from those of room temperature polymerizations. 5. From the third experiment, the external heat supply for the resins during polymerization could temporarily decrease or even reverse shrinkage strains of each material. But, shrinkage re-occurred in the linear nature after completion of heat supply. 6. Linear thermal expansion coefficients obtained from the end of heat supply continuing for an additional 5 minutes, showed that Snap exhibited significantly lower values than the other two poly(methyl methacrylate) products (p<0.01). Moreover, little difference was found between the mean linear thermal expansion coefficients obtained from two different heating durations (p>0.05).

• Journal of dental hygiene science
• /
• v.15 no.4
• /
• pp.445-456
• /
• 2015

The aim of this study was to identify an effective control method of metabolic syndrome (MS) and oral diseases by investigating relationship between of MS and periodontal disease, tooth loss of the adult men and woman. We analyzed and concluded as follows, using a nationwide representative sample, in 8,225 middle senior citizens based on raw data of the 5th National Nutrition Survey in 2010, 2012. The data were analyzed by descriptive statistics, chi-squared test, and logistic regression using SAS ver. 9.2 program. The results are as follows, for correlation of metabolic component to periodontal disease, it was found that in men, the periodontal disease odds ratio of the group with abnormal fasting blood glucose increased 1.27 fold (95% confidence interval [CI], 1.04~1.54), and in woman, the odds ratios of the group with abnormal high density lipoprotein cholesterol increased 1.45 fold (95% CI, 1.22~1.72) and the odds ratio of the group with abnormal obesity increased 1.44 fold (95% CI, 1.17~1.77). For correlation of MS to periodontal disease, it was found that the odds ratio of periodontal disease in the woman at-risk group increased 1.55 fold (95% CI, 1.19~2.01) and that of the group with MS increased 2.25 fold (95% CI, 1.68~3.02). For correlation of woman's metabolic component to missing teeth, it was found that the odds ratio of group with abnormal blood pressure increased 1.41 fold (95% CI, 1.10~1.82). For correlation of woman's MS to missing teeth, it was found that the odds ratio of missing teeth in the group with MS increased 1.48 fold (95% CI, 1.07~2.04). It is considered that a public health project comprising preventive and systematic disease management is necessary for controlling MS and oral disease. The findings of the study are expected to lay the foundation for the development of oral health promotion programs.

• Radiation Oncology Journal
• /
• v.11 no.1
• /
• pp.51-58
• /
• 1993

We tried to establish the theoretical basis of clinical use of combined modality of hyperthermia and radiation therapy. For this purpose, we made an in vitro experiment in order to get the synergistic and/or additive effects on the cell killing of hyperthermia combined with radiation therapy by using the microwave-hyperthermia machine already installed at our department. In our experiment, we use two human cell lines: MKN-45 (adenocarcinoma of stomach) and K-562 (leukemia cell lines). In cases of combined treatments of hyperthermia and gamma-irradiation, the therapeutic effect was the highest in the simultaneous trial. Hyperthermia after gamma irradiation showed slightly higher therapeutic effect than that before irradiation without significant difference, but its effect was the same in the interval of 6 hours between hyperthermia and irradiation. The higher temperature and the longer treatment time were applied, the higher therapeutic effects were observed. We could observe the thermoresistance by time elapse at $43^{\circ}C$. When hyperthermia was done for 30 minutes at the same temperature, thermal enhancement ratio (TER) at DO. 01 (dose required surviving fraction of 0.01) were $2.5{\pm}0.08,\;3.75{\pm}0.18$, and $5.0{\pm}0.15\;at\;436{\circ}C,\;44^{\circ}C,\;and\;45^{\circ}C$ respectively in K-562 leukemia cell lines. Our experimental data showed that more cell killing effect can be obtained in the leukemia cell lines, although they usually are known to be radiosensitive, when treated with combined hyperthermia and radiation therapy. Furthermore, our data show that leukemia cell lines may have various intrinsic radiosensitivity, especially in vitro experiments. The magnitude of cell killing effect, however, will be less than that of MKN-45.

• Journal of Veterinary Clinics
• /
• v.30 no.3
• /
• pp.178-185
• /
• 2013

This study evaluated the effects of milk yield on the postpartum health and reproductive performance of dairy cows. In total, data were collected from 1,060 cows on six dairy farms, including their milk production, body condition score (BCS), postpartum disorders, and reproductive performance. The lactation data were grouped based on the 305-day milk yield into control (< 10,000 kg, n = 445) and high milk yield (${\geq}$ 10,000 kg, n = 615) groups. The milk fat and protein, and BCS were lower during the first 5 months postpartum in the high milk yield group compared with the control group (p < 0.01). Ovarian cysts were more frequent (p < 0.0001) in the high milk yield group (28.6%) than in the control group (15.3%), whereas endometritis tended to be less frequent in the high milk yield group (29.6%) than in the control group (35.1%, p = 0.06). A higher proportion of cows tended to receive reproductive hormones (p = 0.06) in the high milk yield group (62.4%) than in the control group (56.6%). The probability of a pregnancy after first insemination tended to be lower (odds ratio = 0.78, p = 0.07) in the high milk yield group (30.2%) than in the control group (35.2%). Furthermore, the hazard of pregnancy by 210 days in milk was lower in the high milk yield group (hazard ratio = 0.84, p = 0.04) than in the control group, which resulted in a 20-day increase in the median interval to pregnancy. In conclusion, high milk yield was related to lower milk fat and protein, lower BCS, an increased incidence of ovarian cysts, and increased use of reproductive hormones, which resulted in decreased reproductive performance of dairy cows.

• Journal of Oral Medicine and Pain
• /
• v.30 no.2
• /
• pp.141-148
• /
• 2005

Since many reports for the influence of the essential oils on the oral microorganism were presented, it is important to use the essential oils in clinical field. At the present day which emphasized the quality of life, oral malodor is one of the serious problems, so we need to try to decrease of oral malodor. This study was designed to make on evidence of the effect of essential oils to oral malodor clinically and to develop on effective treatment for oral malodor by using the dental paste which contains essential oils. 40 dental students volunteered to participate in this study and double blind test was used. At the beginning, all subjects were measured their morning malodor prior to this experiment, at the 3cm posterior to their incisal edge of the oral cavity by Halimeter(Interscan Co. Chatsworth, CA). After that we divided the students in half into two groups A and B. We have supplied different tooth pastes, dental paste A and B, to two groups respectively. The dental paste B contained essential oils which are tea tree, lemon and peppermint. All students used different tooth pastes everyday for 3 weeks. And all students were measured their morning malodor every week with the same method by using Halimeter. This study was resulted that ; 1. The dental paste which contains essential oils has continuously decreased the morning malodor during the whole period of experiments. 2. The number of students with increase in their morning malodor was generally decreased in the group B who used the toothpaste which contains essential oils, compared with the group A who used the toothpaste which didn't contain essential oils on the 2nd and 3rd week of the experiment. 3. In the group B, the average data on increasing rate of morning malodor was less than in the group A. 4. In the 2nd and 3rd week of the experiment, the data on the rate of morning malodor of the group B was generally decreased continuously compared with the group A. These results have statistically significance under 95% confidence interval of the difference.(p$\leq$0.05) As the result, the toothpaste which was containing essential oils was effective in decreasing the morning malodor.