• Journal of Korea Planning Association
• /
• v.54 no.5
• /
• pp.76-90
• /
• 2019

The purpose of this study is to analyze the survival characteristics of the restaurant business by trade area type (major and side street). By the increase of the unemployment rate, the new foundation of selt-employment type is increasing. However, due to high competition and economic recession, the sustainability of new foundation is not high. Therefore, in this study, survival analysis was performed considering the individual and commercial characteristics focused on the ordinary restaurants. The major findings are as follow. First, the characteristics of parcel unit and adjacent area have a significant effect on the survival. This means the micro-scopic spatial characteristics should be considered for survival in the location choice. Second, the regional economic characteristics in trade area have a significant effect on survival. Furthermore, these characteristics are different by the trade area type. Third. the development characteristics have a different effect on survival by the building usage and trade area type. Finally, regional economic characteristics have a significant effect on survival. These results are expected to be used as basic data for commercial location selection and trade area analysis system in the private and public sectors.

• Communications for Statistical Applications and Methods
• /
• v.31 no.1
• /
• pp.155-178
• /
• 2024

Regression discontinuity (RD) design is one of the most widely used methods in causal inference for estimation of treatment effect when the treatment is created by a cutpoint from the covariate of interest. There has been little attention to RD design, although it provides a very useful tool for analysis of treatment effect for censored data. In this paper, we define the causal effect for survival function in RD design when the treatment is assigned deterministically by the covariate of interest. We propose estimators of this causal effect for survival data by using transformation, which leads unbiased estimator of the survival function with local linear regression. Simulation studies show the validity of our approach. We also illustrate our proposed method using the prostate, lung, colorectal and ovarian (PLCO) dataset.

• Journal of Gastric Cancer
• /
• v.1 no.3
• /
• pp.136-143
• /
• 2001

Purpose: The prognosis for gastric cancer with peritoneal seeding is very poor, and the role of surgical intervention is limited. We evaluated the effect of radical removal of primary and metastatic lesions on survival in gastric cancer with peritoneal seeding. Materials and Methods: From May 1989 to March 1999 at Kosin University Gospel Hospital, 115 patients revealed gastric cancer with peritoneal seeding but without liver or lung metastasis and without follow-up loss. The study group included 86 patients who underwent surgery for radical removal of primary gastric and metastatic peritoneal lesions. The control group included 29 patients who experienced incomplete removal of primary or metastatic lesions. Both groups received intraoperative intraperitoneal chemotherapy using mytomycin or cisplatin, and 25 patients underwent postoperative intravenous chemotherapy. Results: The median survival times in the study and the control groups were 13 months and 4 months, respectively (p<0.0001). The 1-year, 2-year, and 5-year survival rates were, respectively, $50.6\%,\;18.1\%$, and $11.3\%$ in the study group and $14.8\%,\;3.7\%$ and $0\%$ in the control group (p<0.0001). In the study group, neither postoperative intravenous chemotherapy nor microscopic invasion of the resection margin had any effect on survival, but intraoperative intraperitoneal chemotherapy and degree of peri-toneal seeding, especially the amount of peritoneal seeding, had an effect on survival. In the control group, neither intraperitoneal nor intravenous chemotherapy had any effect on survival, but resection of the primary gastric lesion improved survival. Conclusion: Radical removal of primary gastric and metastatic peritoneal lesions improved the survival rate for gastric cancer with peritoneal seeding. However, a randomized prospective study is needed to correctly evaluate the effect of intraperitoneal or intravenous chemotherapy.

• Oral Biology Research
• /
• v.42 no.4
• /
• pp.228-234
• /
• 2018

The aim of this study was to determine the condition of supportive periodontal therapy (SPT) in implant patients and the effect of SPT on implant long-term survival. Implants placed at the Dept. of Periodontology, Chonnam National University Dental Hospital over a 5-year period, were traced for up to 8 years. Patients who had visited the hospital at least once a year were defined as regular SPT, and patients who were treated by active periodontal therapy were defined as patients with periodontitis. Kaplan-Meier survival analysis was performed based on the observation periods, and the effect of SPT and history of periodontitis on implant survival assessed by chisquare test. A total of 183 patients (age: 21-91, 98 males and 85 females), and 508 implants were used for this study. Three hundred eight implants were under SPT and 87 implants was under regular SPT. For the patients with periodontitis 136 implants were placed. The 5-year survival rate was 94.8%. The overall survival rate in patients who received SPT was 97.1% and 91.0% for those who did not (p=0.004). The survival rate in patients who received regular SPT was 97.7%, and 96.8% for patients received irregular SPT. The survival rate was 93.4% in patients with periodontitis and 95.2% in patients without periodontitis. Among patients with periodontitis, the survival rate was 100.0% in patients who received regular SPT and 89.2% for irregular SPT (p=0.012). These results suggest that regular SPT improves implant survival rate and is more effective in patients with periodontitis.

• STI Policy Review
• /
• v.9 no.1
• /
• pp.55-76
• /
• 2018

This study analyzed the effect of the government R&D subsidy program on long-term firm survival. In order to estimate the average treatment effect for the treated group, we used the survival analysis and matching method by constituting a comprehensive dataset of more than 90,000 observations. The analysis results show that the government R&D subsidy has a negative impact on long-term firm survival. In particular, not only the subsidy does not have a statistically significant effect on firm survival in the relatively short-term, the survival probability of the subsidized firms is statistically significantly lower than the non-subsidized firms after six years. These results can be seen as weakening the justification of government R&D support. There may be problems in the subsidy policy itself and the process of selection of subsidy awardees; however, the more fundamental problem is that the subsidy policy is concluded as the one-time event. Admittedly, it would be difficult for the government to precisely manage the subsidized projects over a long term period. However, in the case of a project in which short-term performance is detected, it would be necessary to provide a step-by-step support to strengthen the firm's competitiveness through further support and continuous development of performance. Of course, mid- and long-term evaluations of subsidy support policy should be performed in parallel with such phased support.

• Communications for Statistical Applications and Methods
• /
• v.10 no.3
• /
• pp.1017-1024
• /
• 2003

An estimation problem of treatment effect for bivariate censored survival data is considered under location shift model between two sample. The proposed estimator is very intuitive and can be obtained in a closed form. Asymptotic results of the proposed estimator are discussed and simulation studies are performed to show the strength of the proposed estimator.

• BMB Reports
• /
• v.35 no.1
• /
• pp.87-93
• /
• 2002

Neural cell survival is an essential concern in the aging brain and many diseases of the central nervous system. Neural transplantation of the stem cells are already applied to clinical trials for many degenerative neurological diseases, including Huntington's disease, Parkinson's disease, and strokes. A critical problem of the neural transplantation is how to reduce their apoptosis and improve cell survival. Neurotrophic factors generally contribute as extrinsic cues to promote cell survival of specific neurons in the developing mammalian brains, but the survival factor for neural stem cell is poorly defined. To understand the mechanism controlling stem cell death and improve cell survival of the transplanted stem cells, we investigated the effect of plausible neurotrophic factors on stem cell survival. The neural stem cell, HiB5, when treated with PDGF prior to transplantation, survived better than cells without PDGF. The resulting survival rate was two fold for four weeks and up to three fold for twelve weeks. When transplanted into dorsal hippocampus, they migrated along hippocampal alveus and integrated into pyramidal cell layers and dentate granule cell layers in an inside out sequence, which is perhaps the endogenous pathway that is similar to that in embryonic neurogenesis. Promotion of the long term-survival and differentiation of the transplanted neural precursors by PDGF may facilitate regeneration in the aging adult brain and probably in the injury sites of the brain.

• Journal of the Korea Safety Management & Science
• /
• v.11 no.4
• /
• pp.261-267
• /
• 2009

The purposes of this article is to analyse how market competition of credit card company affect price(interest rate) and survival length of card users. This paper uses individual account data from a large Korean credit card company during the periods from 2002 to 2006. The findings of our study are as follows. First, market competition of credit card company have a negative effect with interest rate of credit card. Second, market competition of credit card company have a affirmative effect with survival length. Finally, The effect of Increasing delinquency rate due to price increase is smaller than decreasing delinquency rate due to extending survival length.

• Journal of Ginseng Research
• /
• v.15 no.3
• /
• pp.167-170
• /
• 1991

Radiation protective fraction was Isolated and partially purified from Korean white ginseng. The effect of the fraction was studied on the cell survival of W-damaged CHO-Kl cells. As a result, it was found that the fraction increased the survival rate of damaged cells significantly within the dose range of which cytotoxicity did not appear This fraction was separated into two parts by adding butanol, namely the precipitated protein component and the butanol extract. Damaged cells were treated with each of these components and their survival rates were measured. The protein component demonstrated significant increase in the survival rates, while the butanol extract showed no such increment. These results suggest that the radiation protective effect of the ginseng fraction is originated from the butanol-precipitated protein component, not from the butanol-soluble compounds.

• Asian Pacific Journal of Cancer Prevention
• /
• v.16 no.13
• /
• pp.5237-5242
• /
• 2015

Background: Socioeconomic factors are associated with screening in terms of reducing the risk of cervical cancer. This study aimed to clearly establish the effect of screening on variation in socio-economic factor-specific survival estimates. Materials and Methods: Survival estimates were calculated using the life table method for 165 women from the routine care control arm and 67 from the visual inspection with acetic acid screening arm diagnosed with cervical cancer during 2000-2006 in rural south India. Kaplan-Meier survival curves were plotted to compare the variation in survival by socioeconomic factors. Results: Whereas there was a significant variation in survival estimates of the different categories of age at diagnosis among the screen-detected cancers with women aged<50 years having an improved survival, no significant variation was noted among women diagnosed with cervical cancer from the control arm. Compared to the variation among the cancer cases detected in the unscreened control group, screening widened the variation in survival estimates by age and type of house, and reduced the variation by education. The direction of the magnitude of the survival estimates was reversed within the different categories of occupation, marital status and household income in the screen-detected cancer cases compared to control group cancer cases. Also, women diagnosed with stage 1 disease had a very good survival. Conclusions: Screening changed the pattern of survival by socio-economic factors. We found improved survival rates in screened women aged <50 years, with no formal education, manual workers and married women.