• Asia-Pacific Journal of Business
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• v.9 no.4
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• pp.157-180
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• 2018

This paper empirically analyzes how working conditions of employees and executives affect Korean companies' survival. To this end, a survival analysis based on the accelerated failure time model is conducted from the end of December 2012 to the end of September 2018 on the 2012 year-end financial data for corporations whose common stocks have ever been listed either in the KOSPI market or in the KOSDAQ market with fiscal year ending at the end of December. The analysis shows that the average wage level per employee and the number of executives relative to the number of employees threaten while the average duration of service for female employees prolongs firm survival. Here, the average wage level per employee has turned out to worsen firm survivability regardless of the gender of employees in question while the average duration of service improves firm survivability only in case the employees are female: the average duration of service for male employees or the entire employees has turned out not to have any statistically significant influence on firm survival. The average compensation per executive and the percentage of temporary employees have turned out not to have any statistically significant influence on firm survival while the percentage of female employees has shown statistically significant positive influence on firm survival in some, although not all, models employed in our study. These results are expected to be a good reference in the course of our reaching agreements regarding the improvement of working conditions either between firms and employees or among the members of the entire society.

• Biomedical Science Letters
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• v.25 no.1
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• pp.32-39
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• 2019

Conventional high-flux hemodialysis (HD) is not as good as normal kidney function. Morbidity and mortality rates of patients receiving HD are still very high. To increase mid-to-large molecule clearance by combining diffusion and convection, on-line hemodiafiltration (HDF) is required. The objective of this study was to compare long-term survival rate of patients treated with on-line HDF to those who received conventional high-flux HD by reviewing data from Chonnam National University Hospital (CNUH). We selected patients who attended the 'CUNH dialysis center' and agreed to participate in the study. Overall, 40 patients with ESRD switched from high flux HD to on-line HDF or started on-line HDF from August 2007 to December 2009. Additionally, a total of 42 patients receiving conventional high-flux HD during the same period were enrolled. We then reviewed long-term survival rate of patients receiving on-line HDF over the next seven years. When we compared survival rates for seven years, the survival rate of the group receiving on-line HDF was 65% (26/40) while that of the group receiving the conventional high-flux HD was 54.8% (23/42). Although the number of patients was small to see survival difference clearly by one specific dialysis modality, there was somewhat difference in survival rate between the two groups. Indicators such as anemia, calcium-phosphate metabolism, nutritional status, treatment adequacy, and hospitalization were also improved in the group receiving HDF. Overall, results of our study showed beneficial effects of on-line HDF on clinical outcomes and survival in chronic HD patients.

• Industry Promotion Research
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• v.7 no.1
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• pp.1-8
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• 2022

We investigated various types of machine learning methods that can be applied to censored data. Exploratory data analysis reveals the distribution of each feature, relationships among features. Next, classification problem has been set up where the dependent variable is death_event while the rest of the features are independent variables. After applying various machine learning methods to the data, it has been found that just like many other reports from the artificial intelligence arena random forest performs better than logistic regression. But recently well performed artificial neural network and gradient boost do not perform as expected due to the lack of data. Finally Kaplan-Meier and Cox proportional hazard model have been employed to explore the relationship of the dependent variable (t_i, δ_i) with the independent variables. Also random forest which is used in machine learning has been applied to the survival analysis with censored data.

• Journal of the Korean Society of Safety
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• v.32 no.5
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• pp.115-121
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• 2017

This paper is to introduce the main modeling assumptions and data structures associated with right-censored data to describe the successful methodological ideas for analyzing such a field-failure-data when components operating in different environments. The Kaplan - Meier method is the most popular method used for survival analysis. Together with the log-rank test, it may provide us with an opportunity to estimate survival probabilities and to compare survival between groups. An important advantage of the Kaplan - Meier curve is that the method can take into account some types of censored data, particularly right-censoring. The above non-parametric method was used to verify the equality of parts life used in different environments. After that, we performed the life distribution analysis using the parametric method. We simulated data from three distributions: exponential, normal, and Weibull. This allowed us to compare the results of the estimates to the known true values and to quantify the reliability indices. Here we used the Akaike information criterion to find a suitable life time distribution. If the Akaike information criterion is the smallest, the best model of failure data is presented. In this paper, no-nparametrics and parametrics methods are analyzed using R program which is a popular statistical program.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.12
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• pp.7401-7407
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• 2013

Aim: To compare survival outcomes after whole brain radiation therapy (WBRT), stereotactic radiosurgery (SRS), and WBRT plus SRS combination therapy in Korea, by performing a quantitative systematic review. Materials and Methods: We searched 10 electronic databases for reports on Korean patients treated with WBRT or SRS for brain metastases published prior to July 2010. Independent reviewers screened all articles and extracted the data. When a Kaplan-Meier survival curve was available, median survival time and standard errors were calculated. Summary estimates for the outcomes in each study were calculated using the inverse variance random-effects method. Results: Among a total of 2,761 studies, 20 studies with Korean patients (n=1,053) were identified. A combination of 12 studies (n=566) with WBRT outcomes showed a median survival time of 6.0 months (95%CI: 5.9-6.2), an overall survival rate of 5.6% (95%CI: 1-24), and a 6-month survival rate of 46.5% (95%CI: 37.2-56.1). For nine studies (n=412) on SRS, the median survival was 7.9 months (95%CI: 5.1-10.8), and the 6-month survival rate was 63.1% (95%CI: 49.8-74.8). In six studies (n=75) using WBRT plus SRS, the median survival was 10.7 months (95%CI: 4.7-16.6), and the overall and 6-month survival rates were 16.8% (95%CI: 6.2-38.2) and 85.7% (95%CI: 28.3-96.9), respectively. Conclusions: WBRT plus SRS showed better 1-year survival outcome than of WBRT alone for Korean patients with metastatic brain tumors. However, the results of this analysis have to be interpreted cautiously, because the risk factors of patients were not adjusted in the included studies.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.4
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• pp.2125-2129
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• 2016

Background: Stomach cancer is an aggressive malignancy that is difficult to detect at an early stage and therefore is characterized by poor survival rates. Over the last two decades, there has been no report of gastric cancer survival in Khon Kaen province, Thailand. The aim of this retrospective cohort study was to provide up-to-date information about the survival of gastric cancer patients in this province. Materials and Methods: Data from Khon Kaen population-based cancer registry, Faculty of Medicine, Khon Kaen University were newly obtained on 650 patients who were diagnosed with stomach cancer during the period 1 January, 2000 to 31 December, 2012. These were then followed up until death or the end of the study (31 December 2014). We calculated the observed survival with the actuarial life table method, and relative survival, defined as the ratio of observed survival in the group of the stomach cancer patients to the expected survival in the entire Thai population from the estimated generation life tables for Thailand of five-year birth cohorts from 1900 - 2000. Results: The 5 year observed and 5 year relative survival rates were 17.2 % (95% CI: 13.54-21.14) and 18.2 % (95% CI: 14.3-22.4), respectively. The highest 5 year relative survival rates were demonstrated among patients aged 45-65, with stage I or II lesions, with adenocarcinomas, with a body of stomach location, well differentiated and receiving surgery and/or chemotherapy. Conclusions: The observed and relative survival rates were close to each other. Our findings provide basic information beneficial to development of an effective treatment system and appropriately improved population-based cancer registration.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.15
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• pp.6773-6777
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• 2015

We used to LASSO-Cox method for determining prognostic factors of male breast cancer survival and showed the superiority of this method compared to Cox proportional hazard model in low sample size setting. In order to identify and estimate exactly the relative hazard of the most important factors effective for the survival duration of male breast cancer, the LASSO-Cox method has been used. Our data includes the information of male breast cancer patients in Fars province, south of Iran, from 1989 to 2008. Cox proportional hazard and LASSO-Cox models were fitted for 20 classified variables. To reduce the impact of missing data, the multiple imputation method was used 20 times through the Markov chain Mont Carlo method and the results were combined with Rubin's rules. In 50 patients, the age at diagnosis was 59.6 (SD=12.8) years with a minimum of 34 and maximum of 84 years and the mean of survival time was 62 months. Three, 5 and 10 year survival were 92%, 77% and 26%, respectively. Using the LASSO-Cox method led to eliminating 8 low effect variables and also decreased the standard error by 2.5 to 7 times. The relative efficiency of LASSO-Cox method compared with the Cox proportional hazard method was calculated as 22.39. The19 years follow of male breast cancer patients show that the age, having a history of alcohol use, nipple discharge, laterality, histological grade and duration of symptoms were the most important variables that have played an effective role in the patient's survival. In such situations, estimating the coefficients by LASSO-Cox method will be more efficient than the Cox's proportional hazard method.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.10
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• pp.6031-6034
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• 2013

This study describes recent trends in incidence, survival and prevalence of subgroups of esophageal and gastric cancer in Linzhou city between 2003 and 2009. Data of esophageal and gastric cancer for the period of interest were extracted from the Linzhou Cancer Registry. Using information on tumor morphology or anatomical site, data were divided into six groups; esophageal squamous cell carcinoma, esophageal adenocarcinoma, other and unspecified types of esophageal cancer, and cardia, non-cardia, and unspecified anatomical site of stomach cancer. Incidence, survival and prevalence rates for each of the six cancer groups were calculated. The majority of esophageal cancers were squamous cell carcinomas (82%). Cardiac cancer was the major gastric cancer group (64%). The incidence of esophageal squamous cell carcinoma and gastric cardiac cancer increased between 2003 and 2009. Both esophageal and gastric cancer had a higher incidence in males compared with females. Overall survival was poor in all sub-groups with 1 year survival ranging from 45.9 to 65.6% and 5 year survival ranging from 14.7 to 30.5%. Prevalence of esophageal squamous cell carcinoma and gastric cardiac cancer was high (accounting for 80% overall). An increased focus on prevention and early diagnosis, especially in esophageal squamous cell carcinoma and gastric cardiac cancer, is required.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.3
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• pp.937-940
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• 2012

Due to lack of sufficient data on characteristics of breast cancer patients and risk factors for developing metastasis in Iran this study was designed to understand clinical aspects impacting on survival. A cross-sectional study on breast cancer patients was conducted in an oncology clinic of the university hospital between 1995 and 2010. Data were retrieved from medical records and included age, menopausal status, tumor diameter, number of involved nodes, histopathological type, estrogen and progesterone receptor expression, c-erbB-2, primary and secondary metastasis sites, overall survival, disease free interval and type of chemotherapy protocol. The results were analyzed with SPSS 13 software. The mean age of the patients was 49.2 (27-89) years. The primary tumors were mainly ER positive (48%) and PR negative (49.3%). The status of lymph nodes dissected and examined in these patients was unknown in 19 patients (25.3%) while 18 patients (24%) had positive lymph nodes with no report on the number of involved nodes. All of the patients had received antracyclin based chemotherapy in an adjuvant or metastatic setting. Adjuvant hormonal therapy was administered to receptor positive patients. In average, overall survival after recurrence was 30 months (95%CI 24.605-35.325) for non-skeletal versus 42 months (95%CI 31.211-52.789) for skeletal metastasis (P= 0.002). The median survival was also greater for receptor positive patients; 39 months (95%CI 33.716-44.284) for PR+ versus 26 months (95%CI 19.210-32.790) for PR- (P=0.047) and 38 months (95%CI 32.908-43.092) for ER+ versus 27 months (95%CI 18.780-35.220) for ER- patients (P=0.016). No relation was found between site of first metastasis and hormone receptor, age, tumor diameter, DFI and menopausal status. Sites of metastasis were independent of age, size of the tumor, menopausal and hormone receptor status in this study. Overall survival provided significant relations with respect to receptor status and bone metastasis.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.2
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• pp.760-766
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• 2014

This study was performed to determine the effect factors in the survival of cardiac arrest patients. This study involved 4,092 cardiac arrest patients of K province, who were transported by 119 during 2010. The data collection involved using 119 rescue daily reports, cardiopulmonary arrest patients emergency treatment detail reports and 119 paramedics survival data. In conclusion, 119 rescue's interventions in the patients with pre-hospital cardiac arrest have significantly increased survival rates. 119 rescue's interventions included early defibrillation, oxygen supply, airway open, and intravenous access affected significantly survival rate. Therefore there is need to increase 119 rescue's interventions performance to improve survival rate of cardiac arrest patients.