• The Korean Journal of Nuclear Medicine
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• v.33 no.2
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• pp.131-142
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• 1999

Purpose: Either gated myocardial perfusion SPECT or attenuation corrected SPECT can be used to improve specificity in the diagnosis of coronary artery disease. We investigated in this study whether gating or attenuation correction improved diagnostic performance of rest/stress perfusion SPECT in patients having intermediate pre-test likelihood of coronary artery disease. Materials and Methods: Sixty-eight patients underwent rest attenuation-corrected T1-20l/dipyridamole stress gated attenuation-corrected Tc-99m -MIBI SPECT using an ADAC vertex camera (M:F=29:39, aged $59{\pm}12$ years, coronary artery stenosis ${\geq}70%$, one vessel: 13, two vessel: 18, three vessel: 8, normal: 29). Using a five-point scale, three physicians graded the post-test likelihood of coronary artery disease for each arterial territory (1:normal, 2: possibly normal, 3:equivocal, 4. possibly abnormal, 5: abnormal). Sensitivity, specificity and area under receiver-operating-characteristic curves were compared for each operator between three methods : (A) non-attenuation-corrected SPECT; (B) gated SPECT added to (A): and (C) attenuation-corrected SPECT added to (B). Results: When grade 3 was used as the criteria for coronary artery disease, no differences in sensitivity and specificity were found between the three methods for each operator. Areas under receiver-operating-characteristic curves for diagnosis of coronary artery disease revealed no differences between each modality (p>0.05). Conclusion: In patients at intermediate risk of coronary artery disease, gated SPECT and attenuation- corrected SPECT did not improve diagnostic performance.

• Journal of Korea Water Resources Association
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• v.45 no.4
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• pp.393-407
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• 2012

This study suggests the results of temporal and spatial variations for rainfall data in the Korean Peninsula. We got the index of the rainfall amount, frequency and extreme indices from 65 weather stations. The results could be easily understood by drawing the graph, and the Mann-Kendall trend analysis was also used to determine the tendency (up & downward/no trend) of rainfall and temperature where the trend could not be clear. Moreover, by using the FARD, frequency probability rainfalls could be calculated for 100 and 200 years and then compared each other value through the moment method, maximum likelihood method and probability weighted moments. The Average Rainfall Index (ARI) which is meant comprehensive rainfalls risk for the flood could be obtained from calculating an arithmetic mean of the RI for Amount (RIA), RI for Extreme (RIE), and RI for Frequency (RIF) and as well as the characteristics of rainfalls have been mainly classified into Amount, Extremes, and Frequency. As a result, these each Average Rainfall Indices could be increased respectively into 22.3%, 26.2%, and 5.1% for a recent decade. Since this study showed the recent climate change trend in detail, it will be useful data for the research of climate change adaptation.

• Korean Journal of Agricultural and Forest Meteorology
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• v.19 no.3
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• pp.93-101
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• 2017

The distribution of inter-annual variation in temperature would help evaluate the likelihood of a climatic risk and assess suitable zones of crops under climate change. In this study, we evaluated two methods to estimate the standard deviation of temperature in the areas where weather information is limited. We calculated the monthly standard deviation of temperature by collecting temperature at 0600 and 1500 local standard time from 10 automated weather stations (AWS). These weather stations were installed in the range of 8 to 1,073m above sea level within a mountainous catchment for 2011-2015. The observed values were compared with estimates, which were calculated using a geospatial correction scheme to derive the site-specific temperature. Those estimates explained 88 and 86% of the temperature variations at 0600 and 1500 LST, respectively. However, it often underestimated the temperatures. In the spring and fall, it tended to had different variance (e.g., increasing or decreasing pattern) from lower to higher elevation with the observed values. A regression analysis was also conducted to quantify the relationship between the standard deviation in temperature and the topography. The regression equation explained a relatively large variation of the monthly standard deviation when lapse-rate corrected temperature, basic topographical variables (e.g., slope, and aspect) and topographical variables related to temperature (e.g., thermal belt, cold air drainage, and brightness index) were used. The coefficient of determination for the regression analysis ranged between 0.46 and 0.98. It was expected that the regression model could account for 70% of the spatial variation of the standard deviation when the monthly standard deviation was predicted by using the minimum-maximum effective range of topographical variables for the area.

• Journal of Food Hygiene and Safety
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• v.33 no.4
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• pp.259-265
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• 2018

Since Korean housewives are responsible for the dietary practices of family at home, it is important to know what information will make them to buy safe food. This study was designed to determine the role of perceived threats, behavioral assessments, and self-efficacy factors known to promote healthy behavior in health belief models (HBM) based on food safety awareness and behavior of housewives. This study involved 191 housewives, based on key variables such as perceived severity, perceived susceptibility, perceived benefits, perceived barriers, self-efficacy, and purchase behavior. The results showed that higher levels of education and urbanization increased the threat perception and the likelihood of buying safe food. The correlation analysis showed that increased awareness and knowledge of safe foods and interest in health contributed to higher relative benefit or self-efficiency of food, and thus, ensured food safety. The conceptual model of food safety behavior based on the HBM was verified via structural equation analysis. The findings suggest that a suitable model showcasing knowledge levels and relative benefits resulted in a greater impact on purchasing behavior than perceived threats. This study suggests that it is more effective for housewives to provide more preventive information than risk information to purchase safe food.

• Journal of the military operations research society of Korea
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• v.36 no.1
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• pp.77-90
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• 2010

Adapting commercial equipments to military operations may provide the advantage of low cost, reduced acquisition time, and technology advancement. On the other hand, it may also offer the opportunity for a reliability and logistics risk because commercial products, standards, and practices may not meet military requirements. In addition to this, commercial vendors have little experience in providing the technical data required to support military deployment logistics. As more companies are equipped with data aquisition systems for their products, considerable amount of field warranty data has been accumulated. Typically, the field data for a given product comprise with the sales volume and the number of the claims for each period. Three types of product data are considered in this study: military designed equipment operating in a military environment, commercial equipment operating in a military environment, and commercial equipment operating in a commercial environment. We construct a estimation model for each type of data and propose an reliability transform method from a commercial environment to a military environment. Parametric methods for estimating the product reliability are proposed based on maximum likelihood criteria and least square criteria. Then a reliability transform procedure for handling different types of data is proposed in a consistent fashion. A case study is investigated to characterize our model based on a real field warranty data set.

• Proceedings of the KOSOMBE Conference
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• v.1997 no.05
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• pp.374-378
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• 1997

Operative procedures such as core drilling with and without fibular bone grafting have been recognized as the treatment methods for osteonecrosis of femoral head(ONFH) by delaying or preventing the collapse of the femoral head. In addition, core drilling with cementation using polymethylmethacrylate (PMMA) has been proposed recently as another surgical method. However, no definite treatment modality has been found yet while operative procedures remain controversial to many clinicians In this study, a finite element method(FEM) was employed to analyze and compare various surgical procedures of ONFH to provide a biomechanical insight. This study was based upon biomechanical findings which suggest stress concentration within the femoral head may facilitate the progression of the necrosis and eventual collapse. For this purpose, five anatomically relevant hip models were constructed in three dimensions : they were (1) intact(Type I), (2) necrotic(Type II), (3) core drilled only(Type III), (4) core drilled with fibular bone graft(Type IV), and (5) core drilled with cementation(Type V). Physiologically relevant loading were simulated. Resulting stresses were calculated. Our results showed that the volumetric percentage subjected to high stress in the necrotic cancellous region was greatest in the core drilled only model(Type III), followed by the necrotic(Type II), the bone graft (Type IV), and the cemented(Type V) models. Von Mises stresses at the tip of the graft(Type IV) was found to be twice more than those of cemented core(Type V) indicating the likelihood of the implant failure. In addition, stresses within the cemented core(Type V) were more evenly distributed and relatively lower than within the fibular bone graft(Type IV). In conclusion, our biomechanical analyses have demonstrated that the bone graft method(Type IV) and the cementation method(Type V) are both superior to the core decompression method(Type III) by reducing the high stress regions within the necrotic cancellous bone. Also it was found that the core region filled with PMMA(Type V) provides far smoother transfer of physiological load without causing the concentration of malignant stresses which may lead to the failure than with the fibular bone graft(Type IV). Therefore, considering the above results along with the degree of difficulties and risk of infection involved with preparation of the fibular bone graft, the cementation method appears to be a promising surgical treatment for the early stage of osteonecrosis of the femoral head.

• Fire Science and Engineering
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• v.24 no.6
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• pp.1-6
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• 2010

A smoldering ground fire can be a probable cause of reignition of surface fire when transmitted from Fermentation layer to Humus layer with temperature higher than that of ignition. Purpose of this paper is to identify experimental methodology on the potential risk of a smoldering ground fire, which is similar to the real surface fuel bed, and its combustion characteristics. The fuel model designed in this study is composed of 3 layers such as Litter layer, Fermentation layer and Humus layer and 8 Thermocouples are set through 3 layer at each boundary and in between to detect the temperature change and duration of smoldering and propagation velocity. As a result, it was observed that ignition conditions in the boundary between L layer and F layer determined transmission and non-transmisstion to F-H layer. In addition, range of critical humidity at which a smoldering ground fire was transmitted in a material layer was 33~44% and when temperature exceeds $350^{\circ}C$, likelihood of transmission of a smoldering ground fire was high. In the research, the experimental model for multi-layer smoldering ground fire is suggested and information about propagation of smoldering fire, possibility of reignition according to moisture content, propagation velocity and temperature change are obtained, Also, the built-up methods were established to help analyze basic characteristics of smoldering ground fire.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.4
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• pp.459-464
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• 2009

Data and pedigree information for Lori-Bakhtiari sheep used in this study were 6,239 records of lamb mortality from 246 sires and 1,721 dams, collected from 1989 through 2007 from a Lori-Bakhtiari flock at Shooli station in Shahrekord. The traits investigated were cumulative lamb mortality from birth up to 7 days, up to 14 days, up to 21 days, and up to 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 and 12 months of age. The models included fixed factors that had significant effects and random direct genetic, maternal genetic and maternal permanent environmental effects. Variance components were estimated using the restricted maximum likelihood procedure applying three animal models with and without maternal and common environmental effects. The overall mean of cumulative lamb mortality rate was 22.95% from birth to 1 year of age, while the overall mortality rate up to 3 and from 3 to 6 months of age was 6.14% and 12.76%, respectively. The mortality rate after 6 months of age declined as the lambs grew older. The age of dam had no important effect on lamb mortality. The type of birth was more important during the preweaning period than at later ages, and lamb mortality rate was higher in twins. The year of birth, month of birth and sex of lamb significantly (p${\leq}$0.01) affected the cumulative lamb mortality rate at all ages. The least square mean of mortality during the final one-third of the lambing period was higher than the first and middle onethird of the lambing period. Male lambs were found to be at a higher risk of mortality than females. Birth weight of the lamb had a highly significant (p${\leq}$0.01) effect on lamb mortality at all ages as a quadratic regression. Direct and maternal heritability estimates of lamb mortality ranged from 0.01 to 0.13 and 0.01 to 0.05, respectively. Direct heritability increased with age of lamb, while maternal effects (genetic and common environmental) were important in the preweaning period. These results indicate that lamb mortality can be reduced first through farm management practices and secondly by genetic selection. Both animal and maternal effects should be considered in breeding programmes for reducing lamb mortality at preweaning.

• Journal of Yeungnam Medical Science
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• v.17 no.1
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• pp.66-74
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• 2000

Background: During the follow up period after transarterial embolization(TAE), cases of pulmonary metastasis were more prevalent in TAE-treated patients than in TAE-untreated patients. Therefore, a study was conducted to evaluate whether TAE increases the incidence of pulmonary metastasis of hepatocellular carcinoma and to clarify the risk factors for pulmonary metastasis. Methods: From March 1991 to March 1995, 156 patients who had been diagnosed with hepatocellular carcinoma by serology, and radiographic and histologic methods at Yeungnam University hospital were involved in this study. We excluded 12 patients with lung metastasis on initial diagnosis and the others. The remaining 144 patients had been followed up for at least 5 months and, divided into four groups according to lung metastasis and trans-arterial embolization treatment, and evaluated for age, sex, child-pugh score, liver cirrhosis, and level of AFP. Results: Pulmonary metastasis was found in 18.0% (26/144), of which 92.3%(24/26) and 7.7%(2/26) of the patients with and without transarterial chemoembolization, respectively. Of the patients, 23.5% (24/102) with TAE had lung metastais during follow-up periods and 4.7% (2/42) without TAE had lung metastasis. There was more likelihood for lung metastasis after TAE. but there was no difference between two groups in age, sex, child-pugh class, the presence of liver cirrhosis, and AFP. Conclusions: The incidence of pulmonary metastasis of hepatocellular carcinoma after TAE was higher. Child-pugh class was the only related clinical preciptating factors for pulmonary metastasis in TAE in our study. Our results suggest that regular chest X-ray check-ups may be more frequently needed by patients who had TAE treatment for hepatocellular carcinoma.

• Korean Journal of Clinical Laboratory Science
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• v.50 no.2
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• pp.155-163
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• 2018

Bilirubin has an anti-inflammatory effect as an endogenous antioxidant and has been reported to be inversely correlated with hypertension, diabetes, metabolic syndrome, and insulin resistance. On the other hand, there is a lack of research evaluating the association between bilirubin and metabolic syndrome compared to liver-specific indicators. This study examined the association between the total bilirubin and metabolic syndrome prevalence in Korean adults who underwent health screening compared to ALT and GGT. This cross sectional study included 22,568 adult males and females aged 20 years or older who underwent a health examination at the General Hospital of Gyeonggi Province from March 2015 to February 2018. Metabolic syndrome was diagnosed based on the American Heart Association/National Heart, Lung, and Blood Institute (AHA/NHLBI) guidelines. In both genders, the metabolic syndrome diagnosed group had higher liver enzymes, and the total bilirubin and direct bilirubin were lower than those without the metabolic syndrome risk factors. The serum total bilirubin showed a weak inverse correlation with abdominal obesity (r=-0.066 vs r=-0.055) and triglyceride (r=-0.127 vs r=-0.136) in both males and females, which is weaker than ALT and GGT The data were statistically significant. In addition, total bilirubin as well as ALT and GGT in both men and women were not predictors of the likelihood of developing metabolic syndrome.