• Tunnel and Underground Space
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• v.31 no.4
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• pp.211-220
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• 2021

Tunnel collapse often occurs during deep underground tunneling (> 40 m depth) in South Korea. Natural cavities as well as water supply pipes, sewer pipes, electric power cables, artificial cavities created by subway construction are complexly distributed in the artificial ground in the shallow depths of the urban area. For deep tunnel excavation, it is necessary to understand the properties of the ground which is characterized by porous elements and various geological structures, and their influence on the stability of the ground. This study analyzed geological factors for risk assessment in deep excavation in South Korea based on domestic and overseas case study. As a result, a total of 7 categories and 38 factors were derived. Factors with high weights were fault and fault clay, differential stress, rock type, groundwater and mud inrush, uniaxial compressive strength, cross-sectional area of tunnel, overburden thickness, karst and valley terrain, fold, limestone alternation, fluctuation of groundwater table, tunnel depth, dyke, RQD, joint characteristics, anisotropy, rockburst and so forth.

• Journal of Korean Clinical Nursing Research
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• v.15 no.2
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• pp.115-126
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• 2009

Purpose: The purpose of this study was to assess the frequency and characteristics of occupational blood and body fluid exposure for operating room personnel during surgical procedures and identify risk factors. Methods: A self-report questionnaire was used to survey 519 operating room personnel who participated in 132 surgeries in an acute care hospital in Seoul between April 12 and 20, 2006. Results: The response rate was 82% (530/646) and analyzed total 519 except for improper 11 questionnaires. Exposure rate was 45.5% (60/132) during operations and 20.4% (106/519) for operating room personnel. By job categories, the exposure rate was as follows; anesthesiologists and nurses 31.2% (44/141), operators and assistants 22.1% (32/145), circulating nurses 12.0% (11/92), scrub nurses 11.4% (14/123). The mucous membrane-eye exposure with a high risk of transmitting infection was 6.6% (7/106) and the most frequent route of exposure was blood and body fluid touching unprotected skin. In multivariate analysis, the risk factors of exposure were services, duration of operation, a patient who had a peripheral arterial catheter line, and job category. Conclusion: Educational programs and appropriate use of personal protective equipment are necessary to prevent operating room personnel from being exposed to blood and body fluid.

• Journal of Cardiovascular Imaging
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• v.30 no.1
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• pp.62-75
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• 2022

BACKGROUND: Due to its location very close to the bundle of His, mitral annulus calcification (MAC) might be associated with the development of atrioventricular (AV) conduction disturbances. This study assessed the association between MAC and AV conduction disturbances identified by cardiac implantable electronic device (CIED) use and electrocardiographic parameters. The association between MAC and traditional cardiovascular risk factors was also assessed. METHODS: This cross-sectional study analyzed 14,771 participants, predominantly men aged 60-75 years, from the population-based Danish Cardiovascular Screening trial. Traditional cardiovascular risk factors were obtained. Using cardiac non-contrast computed tomography imaging, MAC scores were measured using the Agatston method and divided into absent versus present and score categories. CIED implantation data were obtained from the Danish Pacemaker and Implantable Cardioverter Defibrillator Register. A 12-lead electrocardiogram was available for 2,107 participants. Associations between MAC scores and AV conduction disturbances were assessed using multivariate regression analyses. RESULTS: MAC was present in 22.4% of the study subjects. Participants with pacemakers for an AV conduction disturbance had significantly higher MAC scores (odds ratio [OR], 1.11; 95% confidence interval [CI], 1.01-1.23) than participants without a CIED, whereas participants with a CIED for other reasons did not. Prolonged QRS-interval was significantly associated with the presence of MAC (OR, 1.45; 95% CI, 1.04-2.04), whereas prolonged PQ-interval was not. Female sex and most traditional cardiovascular risk factors were significantly associated with high MAC scores. CONCLUSIONS: MAC was associated with AV conduction disturbances, which could improve our understanding of the development of AV conduction disturbances.

• Journal of Cerebrovascular and Endovascular Neurosurgery
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• v.25 no.2
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• pp.143-149
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• 2023

Objective: The purpose of this nationwide age- and sex- matched longitudinal study was to determine the pyogenic spondylitis (PS) increases the incidence of ischemic stroke (IS) in Korea. Methods: From the National Health Insurance Service (NHIS), we collected the patient data for the period from January 1, 2004 to December 31, 2015. PS was classified according to the International Classification of Disease codes M46.2-M46.8, M49.2, and M49.3. By using a 1:5 age- and sex- stratified matching, a total of 628 patients and 3140 control subjects were included in the study. The IS incidence rates in PS and control group was calculated by using the Kaplan-Meier method. The outcome of hazard ratio of IS was estimated by Cox proportional hazards regression analyses. This study did not exclude PS as a result of postoperative complications. Results: According to the study, 51 patients (8.12%) in the PS group and 201 patients (6.4%) in the control group experienced IS. The adjusted hazard ratio of IS in the PS group was 3.419 (95% CI: 2.473-4.729) after adjusting individual medical condition and demographics. Following the results of subgroup analysis, the risk ratio of IS was greater in most of the subgroup categories (male, female, age <65, age >65, non-diabetic, hypertensive, non-hypertensive, dyslipidemic and non-dyslipidemic subgroup). However, the risk of IS did not differ significantly in diabetic subgroup (95% CI: 0.953-4.360). Conclusions: The risk rate of IS increased in patient with pyogenic spondylitis.

• Environmental Analysis Health and Toxicology
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• v.20 no.2 s.49
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• pp.109-121
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• 2005

A chemical ranking and scoring (CRS-Korea) system was developed and proposed to use as the first step to prioritize the toxic chemicals for the purpose of monitoring and detailed risk assessment that might follow as necessary. The CRS-Korea system takes a basic concept of risk assessment (both human health risk and ecological risk) in that risk score is determined by the product of toxicity score and exposure score. Included in the toxicity category are acute toxicity, chronic/sub -chronic toxicity, carcinogenicity, and other toxicity. The exposure category consists of quantity released to the environment, bioconcentration, and persistence. A consistent scheme and a comprehensive chemical data base are offered in the CRS-Korea system to calculate a score for the each component in the two categories by using specific physicochemical, fate, and toxic properties and the quantity of the chemical used. The toxicity score is obtained by adding up all the individual scores for the components in the toxicity category. The exposure score is determined by multiplication of the score of the quantity released with the sum of persistent score and bioconcentration score. Equal weight is given to the toxicity score and the exposure score. As the CRS-Korea system was applied to identify 50 national priority chemicals, it was found that significant data gap exists on toxicity and fate properties and that the uncertainty associated with estimating the quantify released to the environment is notably high. The proposed CRS system is only a screening tool in the first step toward the priority setting and should be used with expert judgement and other considerations necessary.

• Korean Journal of Health Education and Promotion
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• v.19 no.3
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• pp.51-72
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• 2002

This research was conducted to understand and analyze the health-related behaviors of middle school students and get fundamental research data essential to provide efficient student guidance and public health service at school. The interview using Youth Risk Behavior Surveillance System(YRBSS). Translation and modification for Korean students of the YRBS. The Korean version of YRBS(Youth Risk Behavior Surveillance System) that translation and modification for Korean students of the YRBS developed by the Centers for Disease Control and Prevention(CDC)was used to assessment to health-related behaviors of youth. The interviewees were 1040 enrolled students at middle school in Daegu metropolitan city. YRBSS monitors six categories of priority health behaviors among youth and young adults behaviors that contribute to unintentional and intentional injuries; tobacco use; alcohol and other drug use, sexual behaviors that contribute to unintended pregnancy and sexually transmitted diseases(STDs)(including human immunodeficiency virus infection); unhealthy dietary behaviors; and physical activity. The result shows that over 30% of students rarely or never used safety belt and almost students were rarely or never wore a bicycle helmet. During the 12 months preceding the survey, 21.9% female students had felt so sad or hopeless almost every day for $\geq$ 2weeks in a row that they stopped doing some usually activities 20.5% of male middle school students have ever tried cigarette smoking. 26.2% of male students and 27.2% do female students had had over one drinks of alcohol during their lifetime(lifetime alcohol use). 47% of male students had had over one drinks of alcohol on $\geq$ 1 of the 30 days preceding the survey(current alcohol use). Over one half of female student were thought they were overweight. These results suggest that some risk behaviors be very prevalent in a korean middle school students and priority health-risk behaviors, which contribute to the leading cause of mortality and morbidity among youth and adult, often are establish during middle school age, extend into adulthood, are interrelated. Among both children and adults, the leading causes of death are closely linked to these behaviors. Among adults, chronic diseases such as cardiovascular disease, cancer, and diabetes are the national leading killers. Practicing healthy behaviors, such as eating low-fat, high-fruit-and-vegetable diets, getting regular physical activity, and refraining from tobacco use, would prevent many premature deaths. Because health-related behaviors are usually established in childhood, positive choices need to be promoted before damaging behaviors are initiated or become ingrained.

• Journal of Venture Innovation
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• v.5 no.2
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• pp.1-14
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• 2022

Mobile shopping goes beyond the level of a tool that simply supports consumers' shopping in-store and creates a new level of experience for consumers through offline connection. It is important to acquire new customers in order to gain a competitive advantage through mobile shopping, but it is more important to maintain a continuous transaction relationship with the secured customers. Existing mobile shopping-related studies can be largely classified into three categories such as a study on the characteristics of mobile consumers, a study on the characteristics of a mobile shopping mall, and a study on the characteristics of mobile shopping itself. Therefore, this study aimed to analyze the impact of perceived value, perceived risk, and innovativeness on trust in mobile shopping. In order to investigate the impact of perceived value, perceived risk, consumer innovativeness on the trust in mobile shopping, consumers who have experience in purchasing products through mobile were investigated. The data collected in this study were verified the reliability and validity of the measurement items based on the measurement validation process. In this study, regression analysis was performed by selecting perceived value, perceived risk, innovativeness as independent variables, and trust as dependent variables. As a result of the analysis, perceived value, innovativeness had a positive impact on trust and perceived risk had a negative impact on trust. As a result of analysis, three hypotheses were supported. Finally, implications of the research are presented, and limitations and directions for future research are described.

• Journal of Korean Tunnelling and Underground Space Association
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• v.18 no.5
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• pp.453-467
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• 2016

Overall risks that can occur in a shield TBM tunnelling are studied in this paper. Both the potential risk events that may occur during tunnel construction and their causes are identified, and the causal relationship between causes and events is obtained in a systematic way. Risk impact analysis is performed for the potential risk events and ways to mitigate the risks are summarized. Literature surveys as well as interviews with experts were made for this purpose. The potential risk events are classified into eight categories: cuttability reduction, collapse of a tunnel face, ground surface settlement and upheaval, spurts of slurry on the ground, incapability of mucking and excavation, and water leakage. The causes of these risks are categorized into three areas: geological, design and construction management factors. Bayesian Networks (BN) were established to systematically assess a causal relationship between causes and events. The risk impact analysis was performed to evaluate a risk response level by adopting an Analytic Hierarchy Process (AHP) with the consideration of the downtime and cost of measures. Based on the result of the risk impact analysis, the risk events are divided into four risk response levels and these levels are verified by comparing with the actual occurrences of risk events. Measures to mitigate the potential risk events during the design and/or construction stages are also proposed. Result of this research will be of the help to the designers and contractors of TBM tunnelling projects in identifying the potential risks and for preparing a systematic risk management through the evaluation of the risk response level and the migration methods in the design and construction stage.

• Proceedings of the Korea Concrete Institute Conference
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• 1993.04a
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• pp.47-52
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• 1993

Admixtures for concrete placed underwater have been developed to the stage that they are now widely used. The use of this type of product allows concrete to be placed underwater with far less risk than was previously possible. One of the problems facing users of underwater concreting admixtures is how does one test such products in order to access their performance initially while minimizing the expense of carrying out site trials. This paper will introduce three categories of laboratory test for underwater concrete listed next : fluidity test, non-segregation test, strength test. Trial underwater concretes were ordinary Portland cement. Strength and workability development and segregation resistance properties of the concrete under the coexistence of some kinds of superplasticizer were studied for this laboratory tests.

• Journal of Families and Better Life
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• v.26 no.6
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• pp.143-158
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• 2008

The purpose of the study was to investigate the wife and husband role division in household financial management between dual-income household and single-income household. Household financial management included the following five categories: financial planning, consumption/expenditure management, savings/investment management, risk management and credit management. Data for this research was collected through 610 married women living in Seoul, Korea. Using SAS-PC program, Chi-square and t-test Analyses were executed. The results showed that dual- and single-income households tend to have different perspectives on marital role division in household management. Wives of dual-income households had more significant roles in financial management rather than wives of single income households. Especially, wives of dual-income managed more active credit management and saving/investment management. On the other hand, wives of single-income households played a major role in making decision over cheap items than that of wives of dual-income household.