• Journal of Preventive Medicine and Public Health
• /
• v.34 no.2
• /
• pp.157-165
• /
• 2001

Objectives : To identify the risk factors of cerebrovascular disorders(CVD) in Koreans using a nested case-control study. Methods : The cohort consisted of beneficiaries who had taken health examinations of the Korea Medical Insurance Corporation (KMIC cohort: 115,600 persons) in 1990 and 1992 consecutively. Four hundred and twenty five (425) cases were selected following the validation of diagnosis among 2,026 reported CVD (160-168) inpatients during the year from 1993 to 1997. Controls were matched (1:1) with age and gender of the cases among inpatients without CVD during the same period. The source of data in this study were the files of the 1990 health examinations and the 1992 health questionnaires, as well as an additional telephone survey undertaken from March to November 1999. Results : In a bivariate analysis and multiple logistic regression analysis, risk factors for total CVD were hyperglycemia and hypertension. Unrespectively, the odds ratio of ex-smoker was significantly lower than that of those who had never smoked. The risk factors for ischemic CVD also were hyperglycemia and hypertension. However, only blood pressure was found to be a risk factor for hemorrhagic CVD. Hypercholesterolemia was not a risk factor for total CVD, ischemic CVD, and hemorrhagic CVD. Conclusion : We concluded that the most important risk factor for CVD (including subtype) in Koreans was hypertension.

• Journal of the Korea Convergence Society
• /
• v.12 no.8
• /
• pp.215-228
• /
• 2021

The purpose of this qualitative study was to identify cultural factors among older Americans that could influence them to accept new welfare technologies. This study also explored how social and cultural-based plans could increase the acceptability of welfare technologies for improving the quality of life of older adults in the future. In-depth interviews were conducted with ten professionals who work with older adults. The collected interview data were subsequently analyzed using a two-cycle open coding process. The data analysis generated 29 codes that were organized into 7 primary codes, or categories, and 22 secondary codes nested within the primary codes. Several themes were identified: individualism, family-oriented culture, pragmatism, low-context culture, privacy, fun-seeking culture, and a less hierarchical culture. These findings will inform the development of a future survey to examine the relationship between older adults' intentions when using technology and socio-cultural factors in community settings. In order to explore the different impact levels of the cultural factors found in this study, the future study will need to include measures for identifying socio-cultural variations among individuals in one country or across countries.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.46 no.1
• /
• pp.10-23
• /
• 2009

In this paper we propose a novel mobile terminal software architecture supporting energy efficient handover operation in heterogeneous networks. Since the legacy proposals for L3 handover are mostly dependent on IETF Mobile IP which has some problems in movement detection mechanism and no considerations on nested heterogeneous network environment as a result they make serious overload on networks and terminals by performing unnecessary handover in such network environments. The proposed architecture has terminal-oriented network selection and switching architecture where a mobile terminal periodically monitors network status and selects the optimum network, and reduces energy consumption by making L3 handover of Mobile IP to the finally selected network. The network selection method first picks up some candidate networks by considering a terminal speed and power consumption estimation, and determines the final target handover network among the candidates after evaluating multiple factors including QoS required by a terminal, network status, user preference and terminal battery status. Finally we verify the functionality and performance of the energy efficient vertical handover architecture by means of adopting it into a real mobile terminal.

• Journal of Genetic Medicine
• /
• v.9 no.2
• /
• pp.78-83
• /
• 2012

Purpose: The aim of this nested case-control study was to investigate the association between hepatocyte growth factor (HGF) concentrations in maternal plasma and the risk of developing preeclampsia. Materials and Methods: Plasma HGF concentration were measured in 52 women who subsequently developed preeclampsia and 104 normal pregnant women at the time of genetic amniocentesis (15-20 weeks) by enzyme-linked immunosorbent assay. Results: Maternal plasma HGF concentrations were significantly higher in women with subsequent preeclampsia (median: 737.8 ng/mL vs. 670.4 ng/mL, P=0.003) than in normal controls. However, HGF concentrations were not significantly different between subgroups by preeclamptic complications. After adjusting for potential confounding factors, women with HGF concentrations ${\geq}702.5ng/mL$ had a 3.2-fold increased risk (95% CI 2.7-5.4, P<0.001) of subsequent development of preeclampsia compared with women with HGF concentrations <702.5 ng/mL. Conclusion: Elevated maternal plasma HGF concentrations in the early second-trimester are associated with an increased risk of developing preeclampsia.

• The Journal of Korean Association of Computer Education
• /
• v.16 no.1
• /
• pp.51-61
• /
• 2013

This study is to investigate the effecting factors on using ICT ability, and using computers for learning through PISA 2009 Korean data. Multi-level analysis is adapted to hierarchical nested data. Results show as follows: First, using ICT ability is affected by variables on the student level, but not on the school level, except in ESCS. Second, using computers for the purpose of learning at home is also affected by variables on the student level, but not on the school level, except in ESCS and in the size of region. Third, using computers for learning at the school is more influenced by variables on the school level like ESCS, the size of region, the ratio of computers, and the student-teacher ratio. The results suggest planning a computer education policy with considering both personal and school differences based on the multi-level approach.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.43 no.8 s.350
• /
• pp.25-34
• /
• 2006

In this paper DynaMoNET is suggested as a novel IPv6-based multi-homed mobile network architecture which is composed of nested mobile ad hoc networks dynamically coming together through wireless personal area networks. Each ad hoc network has a mobile router which may work as a root mobile router instead of fixed mobile routers in a DynaMoNET. A root mobile router provides the reliable Internet connectivity for the entire mobile network. This paper includes a innovative handover protocol for multi-homed mobile networks, network switchover algorithm considering multiple decision factors, root mobile router election process based on token-based algorithm fast root mobile router discovery algorithm and fault avoidance mechanism to support reliable Internet connectivity. Finally the system architecture of a mobile router is given in detail.

• Journal of Korean Society of Transportation
• /
• v.22 no.3 s.74
• /
• pp.41-48
• /
• 2004

This research develops a model of participation and scheduling choice of urban leisure activity. A nested legit model was found to be an appropriate approach. Data collected from Deagu and Pohang City were used for empirical estimation of model parameters. The empirical results confirmed several behavioral aspects associated with participation and scheduling choice of urban leisure activity. The paper presents a discussion on implications that can be inferred from the empirical results. Finally, future potential research question are also discussed.

• Biotechnology and Bioprocess Engineering:BBE
• /
• v.11 no.6
• /
• pp.510-515
• /
• 2006

The putative EPA synthesis gene cluster was mined from the entire genome sequence of Shewanella oneidensis MR-1. The gene cluster encodes a PKS-like pathway that consists of six open reading frames (ORFs): ORFSO1602 (multi-domain beta-ketoacyl synthase, KS-MAT-4ACPs-KR), ORFSO1600 (acyl transferase, AT), ORFSO1599 (multi-domain beta-ketoacyl synthase, KS-CLF-DH-DH), ORFSO1597 (enoyl reductase, ER), ORFSO1604 (phosphopentetheine transferase, PPT), and ORFSO1603 (transcriptional regulator). In order to prove involvement of the PKS-like machinery in EPA synthesis, a 20.195-kb DNA fragment containing the genes was amplified from S. oneidensis MR-1 by the long-PCR method. Its identity was confirmed by the methods of restriction enzyme site mapping and nested PCR of internal genes orfSO1597 and orfSO1604. The DNA fragment was cloned into Escherichia coli using cosmid vector SuperCos1 to form pCosEPA. Synthesis of EPA was observed in four E. coli clones harboring pCosEPA, of which the maximum yield was 0.689% of the total fatty acids in a clone designated 9704-23. The production yield of EPA in the E. coli clone was affected by cultivation temperature, showing maximum yield at $20^{\circ}C$ and no production at $30^{\circ}C$ or higher. In addition, production yield was inversely proportional to glucose concentration of the cultivation medium. From the above results, it was concluded that the PKS-like modules catalyze the synthesis of EPA. The synthetic process appears to be subject to regulatory mechanisms triggered by various environmental factors. This most likely occurs via the control of gene expression, protein stability, or enzyme activity.

• Journal of Preventive Medicine and Public Health
• /
• v.45 no.4
• /
• pp.235-243
• /
• 2012

Objectives: Nail has been a substitute DNA source for genotyping. To investigate the integrity and consistency of nail DNA amplification for biomarker study, nail clippings from 12 subjects were collected at monthly intervals. The possibility of longer amplification and existence of GAPDH RNA/protein, were also investigated with three nail samples. Methods: Three primer sets were designed for quantitative amplification of nuclear and mitochondrial genes and analysis of their consistency. The mean threshold cycles in amplification of the target genes were compared to test the consistency of polymerase chain reaction (PCR) performance among individual factors including age groups, sex, family, the nail source, and by the size of the amplification segments. Results: The amplification of the target genes from nail DNA showed similar integrity and consistency between the nail sources, and among the serial collections. However, nail DNA from those in their forties showed earlier threshold cycles in amplification than those in their teens or seventies. Mitochondrial DNA (mtDNA) showed better DNA integrity and consistency in amplification of all three targets than did nuclear DNA (nucDNA). Over 9 kb of mtDNA was successfully amplified, and nested quantitative PCR showed reliable copy numbers (%) between the two loci. Reverse transcription PCR for mRNA and immunoblotting for GAPDH protein successfully reflected their corresponding amounts. Regarding the existence of RNA and protein in nails, more effective extraction and detection methods need to be set up to validate the feasibility in biomarker study. Conclusions: Nail DNA might be a feasible intra-individual monitoring biomarker. Considering integrity and consistency in target amplification, mtDNA would be a better target for biomarker research than nucDNA.

• Korea Real Estate Review
• /
• v.28 no.3
• /
• pp.21-35
• /
• 2018

The recent performance of residential mortgages demonstrated how default risk operated separately from prepayment risk. In this study, we investigated the determinants of the borrowers' decisions pertaining to early termination through default from the mortgage performance data released by Freddie Mac, involving securitized mortgage loans from January 2011 to September 2013. We estimated a Cox-type, proportional hazard model with a single risk on fundamental factors associated with default options for individual mortgages. We proposed a mortgage default model that included two specifications of delinquency: one using a delinquency binary variable, while the other using a delinquency probability. We also compared the results obtained from two specifications with respect to goodness-of-fit proposed in the spirit of Vuong (1989) in both overlapping and nested models' cases. We found that a model with our proposed delinquency probability variable showed a statistically significant advantage compared to a benchmark model with delinquency dummy variables. We performed a default prediction power test based on the method proposed in Shumway (2001), and found a much stronger performance from the proposed model.