• The Journal of Engineering Geology
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• v.17 no.1 s.50
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• pp.57-64
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• 2007

This study was conducted to characterize on the relationships among rainfall intensity, slope angle and pore water pressure in the gneissic weathered soil by landslide laboratory flume tests. Under the several test conditions dependent on rainfall intensity and slope angle, the authors measured pore water pressure, failure and displacement of slope on a regular time interval. According to the test results, the increasing times of pore water pressures have direct proportional trends to the rainfall intensity. The pore water pressure was increased earlier at the head part of slope than the toe part. Compared with the test results of Chae et al(2006), the results of this study explain that the seepage velocity in the gneissic weathered soil is slower than that in the standard sands. It results in faster and ear-lier increase of pore water pressure at the head part of slope due to slow flow of water in the gneissic weathered soil. In case of the relationship between slope angle and pore water pressure, gentle slope angle has faster increase of pore water pressure than steeper slope angle. It is also thought to be due to slow seepage velocity and flow velocity in the gneissic weathered soil.

• The Korean Journal of Applied Statistics
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• v.23 no.4
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• pp.705-713
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• 2010

Predicting survival from microarray data is not easy due to the problem of high dimensionality of data and the existence of censored observations. Also the limitation of individual gene analysis causes the shift of focus to the level of gene sets with functionally related genes. For developing a survival prediction model based on pathway information, the methods for selecting a supergene using principal component analysis and testing its significance for each pathway are discussed. Besides, the performance of gene filtering is compared.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.8
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• pp.4013-4017
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• 2016

Background: To compare the pathological findings and oncologic outcomes of stage IA cervical carcinoma patients, between adenocarcinoma and squamous cell carcinoma cases. Materials and Methods: A total of 151 medical records of stage IA cervical carcinoma patients undergoing primary surgical treatment during 2006-2013 were reviewed. Information from pathological diagnosis and recurrence rates were compared with descriptive statistical analysis. The Kaplan-Meier method and Cox proportional hazards model were used for survival analysis. Results: The median age was 48.9 years. There was no significant difference in rates of lymph node, parametrium, uterine, vaginal, or ovarian metastasis, when comparing adenocarcinoma with squamous cell carcinoma. Overall recurrence rates of adenocarcinoma (5.7%) and squamous cell carcinoma (2.6%) were not statistically significant different, even when stratified by stage. When comparing progression free survival with squamous cell carcinoma, adenocarcinoma had an HR of 0.448 (0.073-2.746), p=0.386. Conclusions: Microinvasive adenocarcinoma of cervix has similar rate of extracervical involvement and oncologic outcomes to squamous cell carcinoma.

• Journal of Korean Academy of Nursing
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• v.44 no.5
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• pp.573-580
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• 2014

Purpose: This study was conducted to analyze intubation survival rates according to characteristics and to identify the risk factors affecting deliberate self-extubation. Methods: Data were collected from patients' electronic medical reports from one hospital in B city. Participants were 450 patients with endotracheal intubation being treated in intensive care units. The collected data were analyzed using Kaplan-Meier estimation, Log rank test, and Cox's proportional hazards model. Results: Over 15 months thirty-two (7.1%) of the 450 intubation patients intentionally extubated themselves. The patients who had experienced high level of consciousness, agitation. use of sedative, application of restraints, and day and night shift had significantly lower intubation survival rates. Risk factors for deliberate self-extubation were age (60 years and over), unit (neurological intensive care), level of consciousness (higher), agitation, application of restraints, shift (night), and nurse-to-patient ratio (one nurse caring for two or more patients). Conclusion: Appropriate use of sedative drugs, effective treatment to reduce agitation, sufficient nurse-to-patient ratio, and no restraints for patients should be the focus to diminish the number of deliberate self-extubations.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.4
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• pp.1563-1566
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• 2014

Background: Esophageal squamous cell carcinoma (ESCC) accounts for most esophageal cancer in Asia, and is the sixth common cause of cancer-related deaths worldwide. Previous studies indicated HOXB7 is overexpressed in ESCC tissues, but data on prognostic value are limited. Methods: A total of 76 advanced ESCC cases were investigated. Immunohistochemistry (IHC) was used to detect the expression levels of HOXB7 and Kaplan-Meier curves and Cox regression models to determine prognostic significance. Stratified analysis was also performed according to lymph node (LN) status. Results: Kaplan-Meier curve analysis indicated that HOXB7 positive patients had significantly shorter overall survival (OS) than HOXB7 negative patients. Multivariate analysis using the Cox proportional hazards model indicated only TNM stage and HOXB7 expression to be independent predictors of overall survival of advanced ESCC patients. HOXB7 indicated poor OS in both lymph node negative (LN-) and lymph node positive (LN+) patients. Conclusion: HOXB7 predicts poor prognosis of advanced ESCC patients and can be applied as an independent prognostic predictor.

• Safety and Health at Work
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• v.10 no.4
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• pp.428-436
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• 2019

Background: Metalworking fluids (MWFs) are mixtures with inhalation exposures as mists, dusts, and vapors, and dermal exposure in the dispersed and bulk liquid phase. A quantitative risk assessment was performed for exposure to MWF and respiratory disease. Methods: Risks associated with MWF were derived from published studies and NIOSH Health Hazard Evaluations, and lifetime risks were calculated. The outcomes analyzed included adult onset asthma, hypersensitivity pneumonitis, pulmonary function impairment, and reported symptoms. Incidence rates were compiled or estimated, and annual proportional loss of respiratory capacity was derived from cross-sectional assessments. Results: A strong healthy worker survivor effect was present. New-onset asthma and hypersensitivity pneumonitis, at 0.1 mg/㎥ MWF under continuous outbreak conditions, had a lifetime risk of 45%; if the associated microbiological conditions occur with only 5% prevalence, then the lifetime risk would be about 3%. At 0.1 mg/㎥, the estimate of excess lifetime risk of attributable pulmonary impairment was 0.25%, which may have been underestimated by a factor of 5 or more by a strong healthy worker survivor effect. The symptom prevalence associated with respiratory impairment at 0.1 mg/㎥ MWF was estimated to be 5% (published studies) and 21% (Health Hazard Evaluations). Conclusion: Significant risks of impairment and chronic disease occurred at 0.1 mg/㎥ for MWFs in use mostly before 2000. Evolving MWFs contain new ingredients with uncharacterized long-term hazards.

• Journal of Preventive Medicine and Public Health
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• v.47 no.6
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• pp.289-297
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• 2014

Objectives: This community-based cohort study was performed to investigate the incidence of and factors related to self-reported fragility fractures among middle-aged and elderly women living in rural Korea. Methods: The osteoporosis cohort recruited 430 women 40 to 69 years old in 1999, and 396 of these women were followed over 11 years. In 1999, questionnaires from all participants assessed general characteristics, medical history, lifestyle, menstrual and reproductive characteristics, and bone mineral density. In 2010, self-reported fractures and the date, site, and cause of these fractures were recorded. Cox proportional hazards models were used to calculate hazard ratios (HRs). Results: Seventy-six participants among 3949.7 person-years experienced fragility fractures during the 11-year follow-up. The incidence of fragility fractures was 1924.2 per 100 000 person-years (95% confidence interval [CI], 1491.6 to 2356.8). In the multivariate model, low body mass index (HR, 2.66; 95% CI, 1.13 to 6.24), a parental history of osteoporosis (HR, 2.03; 95% CI, 1.18 to 3.49), and postmenopausal status (HR, 3.50; 95% CI, 1.05 to 11.67) were significantly related to fragility fracture. Conclusions: Fracture prevention programs are needed among postmenopausal, rural, Korean women with a low body mass index and parental history of osteoporosis Korea.

• Research in Community and Public Health Nursing
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• v.17 no.1
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• pp.17-25
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• 2006

Purpose: The goals of this research are to find out factors influencing the duration of work-related disability and to present implications for policies to prevent delayed recovery. Method: The subjects of this study were 238 workers who had been proved to be industrial disaster victims for occupational low back pain between January 1 2000 and December 31 2003. Kaplan-Meier method was used to estimate the proportion of duration of disability associated with low back pain, and Cox proportional hazards analysis was used to identify factors predicting it. The model distinguished main symptom variables affecting acute(${\leq}90\;days$) and chronic phase of disability (>90 days). Result: Fifty percent of the workers had not recovered in 408 days. The results of Cox regression show that delayed duration of disability was predicted by diagnosis, pain radiation (in chronic phase), sex, the size and labor union of the workplace, scheduled rest, compensation from the company, and operation. Conclusion: Duration of disability associated with compensated low back pain is influenced not only by factors related to the company and compensation system but also by individual factors. Thus, future efforts to reduce duration of disability may need to take into account all these factors.

• Knowledge Management Research
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• v.20 no.4
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• pp.131-148
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• 2019

E-commerce in Korea has grown steadily in recent years. E-commerce has provided firms with an effective method to approach potential customers by overcoming geographical and physical barriers. However, despite the rapid growth, many e-commerce businesses closed their businesses and were not able to survive. This study aims to empirically examine the factors that determine the survival of e-commerce businesses in Korea. In particular, this study focuses on the factors related to the notion of institution-based trust that includes delivery, privacy, and security management. This research used the data set about 31,295 e-commerce businesses that have been registered in Seoul. We found that the e-commerce business that does not require extra personal information beyond the standard terms and conditions or provides a feedback mechanism by having an online board to submit a complaint has a higher chance of survival. In addition, the e-commerce business that has a secured web server, shows the specific information about the date of delivery, or provides escrow services is likely to survive longer than others. The research has extended the extant literature on the importance of trust in e-commerce by empirically examining the effects of the institution-based trust factors on the actual survival of e-commerce businesses.

• Communications for Statistical Applications and Methods
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• v.25 no.5
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• pp.471-488
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• 2018

In this paper, we propose extending proportional hazards frailty models to allow a discrete distribution for the frailty variable. Having zero frailty can be interpreted as being immune or cured. Thus, we develop a new survival model induced by discrete frailty with zero-inflated power series distribution, which can account for overdispersion. This proposal also allows for a realistic description of non-risk individuals, since individuals cured due to intrinsic factors (immunes) are modeled by a deterministic fraction of zero-risk while those cured due to an intervention are modeled by a random fraction. We put the proposed model in a Bayesian framework and use a Markov chain Monte Carlo algorithm for the computation of posterior distribution. A simulation study is conducted to assess the proposed model and the computation algorithm. We also discuss model selection based on pseudo-Bayes factors as well as developing case influence diagnostics for the joint posterior distribution through ${\psi}-divergence$ measures. The motivating cutaneous melanoma data is analyzed for illustration purposes.