• Title/Summary/Keyword: Single-index model

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A Study on the Development of "Bufo gargarizans" Habitat Suitability Index(HSI) (두꺼비 서식지 적합성 지수(HSI) 모델개발을 위한 연구)

  • Cho, Gun-Young;Koo, Bon-Hak
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.25 no.2
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    • pp.23-38
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    • 2022
  • This study investigates the characteristics and physical habitat requirements for each Bufo gargarizans life history through a literature survey. After deriving variables for each component of Bufo gargarizans, in order to reduce regional deviations from eight previously studied literature research areas for deriving the criteria for variables, a total of 12 natural habitats of Bufo gargarizanss are selected as spatial ranges by selecting four additional sites such as Umyeonsan Ecological Park in Seoul, Wonheungibangjuk in Cheongju in the central region, Changnyeong Isan Reservoir in the southern region, and Mangwonji in Daegu. This study presents Bufo gargarizans SI, a species endemic to Korea, whose population is rapidly declining due to large-scale housing site development and road development, and develops a Bufo gargarizans HSI model accordingly to improve the function of the damaged Bufo gargarizans habitat and to present an objective basis for site selection of alternative habitat. At the same time, it provides basic data for adaptive management and follow-up monitoring. The three basic habitat requirements of amphibians, the physical habitat requirements of Bufo gargarizans, synthesized with shelter, food, and water, and the characteristics of each life history, are classified into five components by adding space and threats through literature research and expert advice. Variables are proposed by synthesizing and comparing the general characteristics of amphibians, among the previously studied single species of amphibians, the components of HSI of goldfrogs and Bufo gargarizans, and the ecological and physical environmental characteristics of Bufo gargarizans. Afterwards, through consultation with an amphibian expert, a total of 10 variables are finally presented by adjacent forest area(ha), the distance between spawning area and the nearest forest land(m), the soil, the distance from the wetland(m), the forest layered structure, the low grassland space, the permanent wetland area(ha), shoreline slope(%), PH, presence of predators, distance from road(m), presence or absence of obstacles. n order to derive the final criteria for each of the 10 variables, the criteria(alternative) for each variable are presented through geographic information analysis of the site survey area and field surveys of the previously studied literature research area. After a focus group interview(FGI) of 30 people related to the Bufo gargarizans colony in Cheongju, a questionnaire and in-depth interviews with three amphibians experts are conducted to verify and supplement the criteria for each final variable. Based on the finally developed Bufo gargarizans HSI, the Bufo gargarizans habitat model is presented through the SI graph model and the drawing centering on the Bufo gargarizans spawning area

Along and across-wind vibration control of shear wall-frame buildings with flexible base by using passive dynamic absorbers

  • Ivan F. Huergo;Hugo Hernandez-Barrios;Roberto Gomez-Martinez
    • Wind and Structures
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    • v.38 no.1
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    • pp.15-42
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    • 2024
  • A flexible-base coupled-two-beam (CTB) discrete model with equivalent tuned mass dampers is used to assess the effect of soil-structure interaction (SSI) and different types of lateral resisting systems on the design of passive dynamic absorbers (PDAs) under the action of along-wind and across-wind loads due to vortex shedding. A total of five different PDAs are considered in this study: (1) tuned mass damper (TMD), (2) circular tuned sloshing damper (C-TSD), (3) rectangular tuned sloshing damper (R-TSD), (4) two-way liquid damper (TWLD) and (5) pendulum tuned mass damper (PTMD). By modifying the non-dimensional lateral stiffness ratio, the CTB model can consider lateral deformations varying from those of a flexural cantilever beam to those of a shear cantilever beam. The Monte Carlo simulation method was used to generate along-wind and across-wind loads correlated along the height of a real shear wall-frame building, which has similar fundamental periods of vibration and different modes of lateral deformation in the xz and yz planes, respectively. Ambient vibration tests were conducted on the building to identify its real lateral behavior and thus choose the most suitable parameters for the CTB model. Both alongwind and across-wind responses of the 144-meter-tall building were computed considering four soil types (hard rock, dense soil, stiff soil and soft soil) and a single PDA on its top, that is, 96 time-history analyses were carried out to assess the effect of SSI and lateral resisting system on the PDAs design. Based on the parametric analyses, the response significantly increases as the soil flexibility increases for both type of lateral wind loads, particularly for flexural-type deformations. The results show a great effectiveness of PDAs in controlling across-wind peak displacements and both along-wind and across-wind RMS accelerations, on the contrary, PDAs were ineffective in controlling along-wind peak displacements on all soil types and different kind of lateral deformation. Generally speaking, the maximum possible value of the PDA mass efficiency index increases as the soil flexibility increases, on the contrary, it decreases as the non-dimensional lateral stiffness ratio of the building increases; therefore, there is a significant increase of the vibration control effectiveness of PDAs for lateral flexural-type deformations on soft soils.

The Prognostic Value of the Charlson's Comorbidity Index in Patients with Prolonged Acute Mechanical Ventilation: A Single Center Experience

  • Song, Seung Eon;Lee, Sang Hee;Jo, Eun-Jung;Eom, Jung Seop;Mok, Jeong Ha;Kim, Mi-Hyun;Kim, Ki Uk;Lee, Min Ki;Lee, Kwangha
    • Tuberculosis and Respiratory Diseases
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    • v.79 no.4
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    • pp.289-294
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    • 2016
  • Background: The aim of our study was to evaluate the prognostic value of Charlson's weighted index of comorbidities (WIC) in patients with prolonged acute mechanical ventilation (PAMV, ventilator care ${\geq}96$ hours). Methods: We retrospectively enrolled 299 Korean PAMV patients who were admitted in a medical intensive care unit (ICU) of a university-affiliated tertiary care hospital between 2008 and 2013. Survivors were defined as patients who survived for 60 days after ICU admission. Results: The patients' mean age was $65.1{\pm}14.1$ years and 70.6% were male. The mean ICU and hospital length of stay was $21.9{\pm}19.7$ and $39.4{\pm}39.1$ days, respectively. In addition, the 60-day mortality rate after ICU admission was 35.5%. The mean WIC was $2.3{\pm}1.8$, with significant differences between nonsurvivors and survivors ($2.7{\pm}2.1$ vs. $2.1{\pm}1.7$, p<0.05). The area under the curve of receiver-operating-characteristics curve for WIC was 0.593 (95% confidence interval [CI], 0.523-0.661; p<0.05). Based on Kaplan-Meier curves of 60-day survival, WIC ${\geq}5$ had statistically lower survival than WIC <5 (logrank test, p<0.05). In a multivariate Cox proportional hazard model, WIC ${\geq}5$ was associated with poor prognosis (hazard ratio, 1.901; 95% CI, 1.140-3.171; p<0.05). The mortality rate of patients with WIC ${\geq}5$ was 54.2%. Conclusion: Our study showed a WIC score ${\geq}5$ might be helpful in predicting 60-day mortality in PAMV patients.

The relationship between intake of nutrients and food groups and insulin resistance in Korean adults: Using the Fourth Korea National Health and Nutrition Examination Survey (KNHANES IV, 2007-2009) (우리나라 성인의 인슐린 저항성과 관련된 영양소 및 식품군 섭취: 제 4기 국민건강영양조사 자료를 활용하여)

  • Song, SuJin;Paik, Hee-Young;Song, YoonJu
    • Journal of Nutrition and Health
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    • v.46 no.1
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    • pp.61-71
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    • 2013
  • The aim of this study was to examine the relationship between dietary variables and the prevalence of insulin resistance (IR) in middle-aged Korean adults using data from the 2007-2009 Korea National Health and Nutrition Examination Survey. Because IR is closely linked with metabolic syndrome, subjects were divided into three groups according to symptoms of metabolic syndrome: the 'Normal group' without any symptoms, the 'Risk group' with one or two symptoms, and the Metabolic syndrome (MetS) group' with three or more symptoms. Subjects between the ages of 30 and 65 years with no prior diagnosis or treatment for diabetes, hypertension, or dyslipidemia were selected. The number of subjects per group was as follows: 2,085 adults in the Normal group, 3,699 adults in the Risk group, and 1,160 adults in the MetS group. Metabolic syndrome was defined according to Adult Treatment Panel III criteria with modified waist circumference cutoff values (men ${\geq}$ 90 cm, women ${\geq}$ 85 cm). Subjects with HOMA-IR > 2.0 were classified as IR. Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) was calculated using the following formula: (fasting plasma glucose ${\times}$ fasting plasma insulin)/22.5. Nutrients and food groups intake were obtained from a single 24-hour recall. Subjects with IR in the Normal group were more obese and less physically active than non-IR subjects. In the MetS group, subjects with IR were more obese and had a lower prevalence of smoking and drinking, compared with non-IR subjects. Men with IR in the Normal group had a tendency to consume more oils and sugars than non-IR men, while women with IR in the same group had higher intake of carbohydrate, dietary glycemic index, and dietary glycemic load than non-IR women. Women with IR in the Risk group had lower energy intake but higher intake of oils and sugars than non-IR women. In the MetS group, consumption of fruits was higher in subjects with IR than in non-IR subjects. In conclusion, findings of this study suggest that dietary carbohydrate intake, including glycemic index, may be associated with IR in healthy women. Further research in prospective cohort studies in order to examine the effects of dietary carbohydrate on IR incidence will be necessary.

An Analysis on the Anti-poverty Effectiveness of Public and Private Income Transfers; After the Enactment of National Basic Livelihood Security Act (공적 이전과 사적 이전의 빈곤 감소 효과 분석 : 기초생활보장제도 도입 이후를 중심으로)

  • Hong, Kyung-Zoon
    • Korean Journal of Social Welfare
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    • v.50
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    • pp.61-85
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    • 2002
  • Using the 2001 Family Income and Expenditure Survey micro-data, this study analyses the anti-poverty effectiveness of public and private income transfers. In this study, the anti-poverty effectiveness of income transfers is summarized in two ways; 1) the poverty reduction effect of the income transfers, and 2) the poverty reduction efficiency of the income transfers. The poverty reduction effects are measured with several poverty indices including the head-count ratio, poverty gap, and Sen index. Using Beckerman's model, this study also analyses the poverty reduction efficiency of income transfers. This analysis documents substantial differences in the anti-poverty effectiveness of public and private income transfers. Although the private income transfers contribute more to reduce the head-count poverty ratio and Sen index than public income transfers, their differences are significantly reduced after the enactment of National Basic Livelihood Security Act. The results also reveal that the anti-poverty effectiveness of public and private income transfers vary by the types of families. In families headed by elderly and working aged, private income transfers have more anti-poverty effectiveness. But, public income transfers contribute more to reduce poverty than private income transfers among families headed by single adults with children. The results of this study suggest that recent changes in anti-poverty policies in Korea have been strengthened the Government's responsibility. And more importantly, to effectively reduce poverty among the poor families, anti-poverty polices must be designed to consider different family types.

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Modeling the Effect of Intake Depth on the Thermal Stratification and Outflow Water Temperature of Hapcheon Reservoir (취수 수심이 합천호의 수온성층과 방류 수온에 미치는 영향 모델링)

  • Sun-A Chong;Hye-Ji Kim;Hye-Suk Yi
    • Journal of Environmental Impact Assessment
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    • v.32 no.6
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    • pp.473-487
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    • 2023
  • Korea's multi-purpose dams, which were constructed in the 1970s and 1980s, have a single outlet located near the bottom for hydropower generation. Problems such as freezing damage to crops due to cold water discharge and an increase the foggy days have been raised downstream of some dams. In this study, we analyzed the effect of water intake depth on the reservoir's water temperature stratification structure and outflow temperature targeting Hapcheon Reservoir, where hypolimnetic withdrawal is drawn via a fixed depth outlet. Using AEM3D, a three-dimensional hydrodynamic water quality model, the vertical water temperature distribution of Hapcheon Reservoir was reproduced and the seasonal water temperature stratification structure was analyzed. Simulation periods were wet and dry year to compare and analyze changes in water temperature stratification according to hydrological conditions. In addition, by applying the intake depth change scenario, the effect of water intake depth on the thermal structure was analyzed. As a result of the simulation, it was analyzed that if the hypolimnetic withdrawal is changed to epilimnetic withdrawal, the formation location of the thermocline will decrease by 6.5 m in the wet year and 6.8 m in the dry year, resulting in a shallower water depth. Additionally, the water stability indices, Schmidt Stability Index (SSI) and Buoyancy frequency (N2), were found to increase, resulting in an increase in thermal stratification strength. Changing higher withdrawal elevations, the annual average discharge water temperature increases by 3.5℃ in the wet year and by 5.0℃ in the dry year, which reduces the influence of the downstream river. However, the volume of the low-water temperature layer and the strength of the water temperature stratification within the lake increase, so the water intake depth is a major factor in dam operation for future water quality management.

Numerical analysis of geomorphic changes in rivers due to dam pulse discharge of Yeongju Dam (댐 펄스방류로 인한 하천의 지형변화 수치모의 분석(영주댐 중심으로))

  • Baek, Tae Hyoa;Jang, Chang-Laeb;Lee, Kyung Su
    • Journal of Korea Water Resources Association
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    • v.56 no.12
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    • pp.871-881
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    • 2023
  • This study investigates the geomorphic changes and Bed Relief Index of the river downstream of the Yeongju Dam by Nays2DH, a two-dimensional numerical model, in order to grasp the dynamics of the downstream river while applying various flow patterns such as pulse discharge. It shows that the geomorphic and the bed elevations changes are the largest under the condition of the normalized pulse discharge. The total change in the riverbed is 29.88 m for uniform flow, 27.46 m for normalized hydrograph, 29.63 m for pulse flow and 31.87 m for pulse flow with normalized hydrograph which result in the largest variation in scour and deposition. The Bed Relief Index (BRI) increases with time under conditions of uniform flow, pulse flow and pulse flow with normalized hydrograph. However, BRI increased rapidly until 30 hrs after the peak flow (14 hrs), but decreased from 56 hrs under the condition of normalized hydrograph. Therefore, the condition of normalized hydrograph gives greater dynamics than the condition of a single flood or constant flow, and the dynamics increase downstream than upstream, resulting in an effect on improving the environment of the river downstream of the dam.

A Promoter SNP (rs1800682, -670C/T) of FAS Is Associated with Stroke in a Korean Population

  • Kang, Sung-Wook;Chung, Joo-Ho;Kim, Dong-Hwan;Yun, Dong-Hwan;Yoo, Seung-Don;Kim, Hee-Sang;Seo, Wan;Yoon, Jee-Sang;Baik, Hyung-Hwan
    • Genomics & Informatics
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    • v.8 no.4
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    • pp.206-211
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    • 2010
  • The Fas (TNF receptor superfamily, member 6) (FAS)/FAS ligand (FASLG) interaction plays a central role in the regulation of programmed cell death. FAS and FASLG polymorphisms in promoter regions affect transcriptional activities. To investigate whether FAS and FASLG polymorphisms are associated with the development and clinical phenotypes of stroke, 2 promoter single nucleotide polymorphisms (SNPs) in FAS (rs1800682, -670C/T) and FASLG (rs763110, -844C/T) were selected and genotyped by direct sequencing in 220 stroke patients [107 ischemic stroke (IS), 77 intracerebral hemorrhage (ICH), and 36 subarachnoid hemorrhage (SAH)] and 369 control subjects. For the analysis of clinical symptoms, all stroke patients were divided into 3 clinical phenotypes according to the respective results of the National Institutes of Health Stroke Survey (NIHSS) and the Modified Barthel Index (MBI) and the presence or absence of complex regional pain syndrome (CRPS). The SNPStats, SNPAnalyzer, and Helixtree programs were used to analyze the genetic data. Multiple logistic regression models (codominant, dominant, and recessive) were used to estimate odds ratios (ORs), 95% confidence intervals (CIs), and p-values. The promoter SNP rs1800682 was associated with stroke in the codominant (OR=0.48, 95% CI=0.25-0.94, p=0.04) and dominant models (OR=0.51, 95% CI=0.30-0.87, p=0.011). However, a FASLG SNP (rs763110) was not in Hardy-Weinberg equilibrium (p<0.05). In the analysis of stroke types, rs1800682 was associated with IS in the codominant (OR=0.30, 95% CI=0.12-0.74, p=0.025), dominant (OR=0.44, 95% CI=0.23-0.88, p=0.018), and recessive models (OR=0.45, 95% CI=0.21-0.99, p=0.042). The genotype frequencies of rs1800682 were different between ICH and controls in the dominant model (OR=0.49, 95% CI=0.26-0.94, p=0.031) but not between SAH and controls. In the analysis of clinical symptoms, however, rs1800682 was not related to the 3 clinical phenotypes (NIHSS, MBI, and CRPS). These results suggest that a promoter SNP (rs1800682, -670C/T) in FAS may be associated with the development of stroke in the Korean population.

Single Nucleotide Polymorphisms in the Gc Gene for Vitamin D Binding Protein in Common Cancers in Thailand

  • Maneechay, Wanwisa;Boonpipattanapong, Teeranut;Kanngurn, Samornmas;Puttawibul, Puttisak;Geater, Sarayut Lucien;Sangkhathat, Surasak
    • Asian Pacific Journal of Cancer Prevention
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    • v.16 no.8
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    • pp.3339-3344
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    • 2015
  • Background: This case-control study aimed to determine if there were any associations between the two single nucleotide polymorphisms (SNPs) in Gc, rs7041 (Asp416Glu) and rs4588 (Thr420Lys) and 3 common cancers (breast, lung and colorectal) in Thai patients. Materials and Methods: Two hundred and eighty two colorectal, 101 breast and 113 lung cancer patients were recruited from one institute during 2011-2013. The controls were age-matched volunteers who had a negative history of index cancers. In addition, vitamin D levels were compared among different genotypes in the 2 SNPs. Results: The minor allele frequencies of rs7041 (G) and rs4588 (A) were 0.32 and 0.24, respectively. Under the dominant model, the study found significant associations between minor-allele genotypes of the SNP rs7041 (TG/GG) and lung cancer (odds ratio [OR] 1.78, 95% CI 1.05-3.03). When subgroup analysis was performed according to sex and age at diagnosis, the study found that the minor-allele genotypes of rs7041 (TG/GG) were significantly associated with colorectal cancer in patients whose age at diagnosis was more than 60 years (OR 1.67, 95%CI 1.06-2.61) and the minor-allele genotypes of rs4588 (CA/AA) were significantly associated with colorectal cancer in males aged 60 years or less (OR 2.34, 95%CI 1.25-4.37). When SNP combinations (rs7041-rs4588) were examined, the TT-CA combination had a significant protective association with lung cancer (OR 0.44, 95% CI 0.22-0.85). On evaluation of serum 25(OH)D levels in 205 individuals without cancer (males 144, females 61), the proportion of subjects with low serum vitamin D (< 20 ng/ml) in those harboring CA or AA genotypes of rs4588 (41.7%) was significantly higher than the CC genotype (15.5%, p-value < 0.01). Conclusions: Genetic polymorphisms in Gc were associated with lung and colorectal cancers in Thai patients. Lower serum 25(OH)D in minor variants of rs4588 may explain this association.

Effects of macronutrients in mixed meals on postprandial glycemic response (식품 및 음식의 다량영양소 구성 성분에 따른 혈당 반응 연구)

  • Park, Mi-Hyeon;Chung, Sang-Jin;Shim, Jae Eun;Jang, Sung-Hee;Nam, Ki-Sun
    • Journal of Nutrition and Health
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    • v.51 no.1
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    • pp.31-39
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    • 2018
  • Purpose: The aim of study was to determine the effects of carbohydrate, fat, protein, and fiber contents on glycemic responses in a single food item or meal. Methods: Glycemic responses were measured in 30 healthy young adults (17 males and 13 females) with various test foods, including rice, egg whites, bean sprouts, olive oil, noodles, prune, broccoli, Korean dishes, Western dishes, and salad dishes, etc. Test foods were designed to contain various carbohydrate, fat, protein, and fiber contents in single or mixed foods or dishes. After 12 hours of fasting, participants consumed test foods, and the glycemic response was measured for a subsequent 120 min (0, 15, 30, 60, 90, and 120 min). Three hundred and fifty three glycemic responses from 62 foods were collected. The incremental area under the curve (AUC) was calculated for each test food for each subject to examine glycemic responses. Statistical analysis was conducted to identify which macronutrient (carbohydrate, fat, protein and fiber) affected the AUC using a mixed model. Results: Carbohydrates (${\beta}=37.18$, p < 0.0001) significantly increased while fat (${\beta}=-32.70$, p = 0.0054) and fiber (${\beta}=-32.01$, p = 0.0486) significantly reduced the glycemic response. Conclusion: It can be concluded that the glycemic response of a meal can be modified depending on the fat and fiber contents of ingredient foods, even though carbohydrate content is maintained.