• Title/Summary/Keyword: Survival data

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Estimation of mortality coefficients and survivorship curves for minke whales (Balaenoptera acutorostrata) in Korean waters

  • Zhang, Chang-Ik;Song, Kyung-Jun;Na, Jong-Hun
    • Animal cells and systems
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    • v.14 no.4
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    • pp.291-296
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    • 2010
  • Population ecological characteristics of growth and mortality play an important role in understanding the population dynamics of marine mammals. The instantaneous coefficients of natural and bycatch mortality were estimated for minke whales (Balaenoptera acutorostrata) in Korean waters using a population assessment model composed of bycatch and abundance data. The survivorship curve of this population was fitted to the data, and then the curve was revised using age-specific relative bycatchability coefficients ($q_t$). Instantaneous coefficients of natural and bycatch mortality of minke whales were estimated as 0.024/year and 0.076/year, respectively, and from this the survival rate was estimated as 0.905. This estimated survival rate was comparable to other cetaceans in other regions. The $q_t$ for this population ranged from 0.020 to 0.193. The revised survival rates were higher when the $q_t$ was taken into account. The mortality coefficient, survival rate, $q_t$ and survivorship curves had not previously been determined for minke whale in this area. This estimate could serve as fundamental information to assess the status of this population and for conservation and rational management.

Exploring the Impact of Live Commercial Anchors on Business Performance and Survival Strategy: Focusing on Resource Configuration and Environmental Choice

  • ZHANG, Li-Jie;HUANG, Fei
    • East Asian Journal of Business Economics (EAJBE)
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    • v.10 no.4
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    • pp.1-18
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    • 2022
  • Purpose - Through the analysis and research of different characteristics and related mechanisms of live commerce anchors, this paper aimed to help live commerce anchors to strengthen their characteristic advantages, beautify the live broadcast environment, improve resource allocation and enhance business performance, so as to help live commerce anchors to achieve better high-quality development. Research design, data, and methodology - This study was conducted by sample survey method on 361 live commercial anchors who have experience in using major online shopping malls for more than one year. Data analysis methods were frequency analysis, confirmatory factor analysis, reliability analysis, correlation analysis, and structural equation model analysis. Result - Hypothesis 1 through Hypothesis 5 were all supported. The results of this study suggest that professionalism and mutual entertainment of live commercial anchors have a significant impact on business performance, survival strategy, resource allocation and environment selection. The resource allocation and environment selection of live commercial anchors play a mediating role in the professionalism and mutual entertainment of live commercial anchors on business performance and survival strategy. Conclusion -The results implied that the professionalism and inter entertainment of live commercial anchors have a positive impact on business performance and survival strategy. In the new situation, live commercial anchors should further improve their professionalism and mutual entertainment, so as to achieve better development.

The Effect of Situational, Transformational, and Transactional Leadership on Firm Survival During the Crisis of Covid-19: Empirical Evidence from Restaurants Distribution in Thailand

  • Purit PONGPEARCHAN;Jirayu RATTANABORWORN
    • Journal of Distribution Science
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    • v.21 no.8
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    • pp.11-21
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    • 2023
  • Purpose: This study examined the effect of situational, transformational, and transactional leadership on the firm survival of restaurants distribution in Thailand during the COVID-19 pandemic. Following the existing literature, situational, transformational, and transactional leadership are the origin of firm performance leading to firm survival. Therefore, situational, transformational, and transactional leadership were the critical factors in creating the firm implementation of restaurants distribution in Thailand. Research design, data, and methodology: The sample consisted of 400 restaurants in Thailand, and the statistical approach for data analysis was an ordinary least-squares regression. The study analyzed the response bias, validity, and reliability. Results: Significantly, these findings firmly revealed that situational, transformational, and transactional leadership primarily positively affected firm performance. However, the uncertain environmental conditions had a moderate impact, resulting in a negative correlation between the three leadership styles and the company's performance. Conclusions: Despite the COVID-19 situation in Thailand, the research findings show no significant positive correlation between the performance of restaurants distribution and their survival as a business due to the COVID-19 pandemic is rare for firms to endure and survive, including restaurants distribution in Thailand. In conclusion, we have presented practical and theoretical ideas and recommendations for future research.

Comparison of Survival Function Estimators for the Cox's Regression Model using Bootstrap Method (Cox 회귀모형(回歸模型)에서 붓스트랩방법(方法)에 의한 생존함수추정량(生存函數推定量)의 비교연구(比較硏究))

  • Cha, Young-Joon
    • Journal of the Korean Data and Information Science Society
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    • v.4
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    • pp.1-11
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    • 1993
  • The Cox's regression model is frequently used for covariate effects in survival data analysis, But, much of the statistical work has focused on asymptotic behavior so the small sample evaluation has been neglected. In this paper, we compare the small or moderate sample performances of the survival function estimators for the Cox's regression model using bootstrap method. The smoothed PL type estimator and the Link estimator are slightly better than corresponding the PL type estimator and the Nelson type estimator in the sense of the achieved error rates.

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Development of a Rural Population Model Considering Shift-Share Effects in Cohort-Survival Method (집단생잔모델에 변화할당효과를 고려한 농촌지역 인구모델의 개발)

  • Jung, Nam-Su;Lee, Haeng-Woo
    • Journal of Korean Society of Rural Planning
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    • v.12 no.3 s.32
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    • pp.39-42
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    • 2006
  • The purpose of this study is to develop rural population model adapting cohort survival method with sift-share effects. Administrative district in this study is below Myun: about 2,000 population. Population data of rural area in 1990, 1995, and 2000 by age cohort were selected for applying developed model. Damping coefficient from population data was calculated as 7% and results applying this coefficient in rural population data below the error from 12% to 1.06%. In detail, most of cohorts fitted with developed model except from 15 to 29 age groups. Application result of small population area; DaesulMyun revealed that main factor of population change is not natural change but migration.

Conditional Bootstrap Methods for Censored Survival Data

  • Kim, Ji-Hyun
    • Journal of the Korean Statistical Society
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    • v.24 no.1
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    • pp.197-218
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    • 1995
  • We first consider the random censorship model of survival analysis. Efron (1981) introduced two equivalent bootstrap methods for censored data. We propose a new bootstrap scheme, called Method 3, that acts conditionally on the censoring pattern when making inference about aspects of the unknown life-time distribution F. This article contains (a) a motivation for this refined bootstrap scheme ; (b) a proof that the bootstrapped Kaplan-Meier estimatro fo F formed by Method 3 has the same limiting distribution as the one by Efron's approach ; (c) description of and report on simulation studies assessing the small-sample performance of the Method 3 ; (d) an illustration on some Danish data. We also consider the model in which the survival times are censered by death times due to other caused and also by known fixed constants, and propose an appropriate bootstrap method for that model. This bootstrap method is a readily modified version of the Method 3.

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Bayesian Semi-Parametric Regression for Quantile Residual Lifetime

  • Park, Taeyoung;Bae, Wonho
    • Communications for Statistical Applications and Methods
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    • v.21 no.4
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    • pp.285-296
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    • 2014
  • The quantile residual life function has been effectively used to interpret results from the analysis of the proportional hazards model for censored survival data; however, the quantile residual life function is not always estimable with currently available semi-parametric regression methods in the presence of heavy censoring. A parametric regression approach may circumvent the difficulty of heavy censoring, but parametric assumptions on a baseline hazard function can cause a potential bias. This article proposes a Bayesian semi-parametric regression approach for inference on an unknown baseline hazard function while adjusting for available covariates. We consider a model-based approach but the proposed method does not suffer from strong parametric assumptions, enjoying a closed-form specification of the parametric regression approach without sacrificing the flexibility of the semi-parametric regression approach. The proposed method is applied to simulated data and heavily censored survival data to estimate various quantile residual lifetimes and adjust for important prognostic factors.

A Comparison of Testing Methods for Equality of Survival Distributions with Interval Censored Data

  • Kim, Soo-Hwan;Lee, Shin-Jae;Lee, Jae-Won
    • The Korean Journal of Applied Statistics
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    • v.25 no.3
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    • pp.423-434
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    • 2012
  • A two-sample test for equality of survival distribution is one of the important issues in survival analysis, especially for clinical and epidemiological research. With interval censored data, some testing methods have been developed. This study introduces some testing methods and compares them under various situations through simulation study. Based on simulation result, it provides some useful information on choosing the most appropriate testing method in a given situation.

Survival Rates of Cervical Cancer Patients in Malaysia

  • Muhamad, Nor Asiah;Kamaluddin, Muhammad Amir;Adon, Mohd Yusoff;Noh, Mohamed Asyraf;Bakhtiar, Mohammed Faizal;Tamim, Nor Saleha Ibrahim;Mahmud, Siti Haniza;Aris, Tahir
    • Asian Pacific Journal of Cancer Prevention
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    • v.16 no.7
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    • pp.3067-3072
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    • 2015
  • Cervical cancer is the most common malignant cancer of the female reproductive organs worldwide. Currently, cervical cancer can be prevented by vaccination and detected at an early stage via various screening methods. Malaysia, as a developing country faces a heavy disease burden of cervical cancer as it is the second most common cancer among Malaysian women. This population based study was carried out to fulfil the primary aim of determining the survival rates of Malaysian women with cervical cancer and associated factors. Data were obtained from two different sources namely, the Malaysian National Cancer Registry (MNCR) and National Health Informatics Centre (NHIC) from 1st January 2000 to 31st December 2005. Kaplan Meier analyses were conducted to identify the overall survival rates and median survival time. Differences in survival among different ethnic and age group were compared using the log-rank test. A total of 5,859 patients were included. The median survival time for cervical cancer in this study was 65.8 months and the 5-year survival rate was 71.1%. The overall observed survival rates at 1, 3 and 5 years were 94.1%, 79.3% and 71.1% respectively. The log-rank test finding also showed that there were significant differences in the 5-year survival rate among different ethnic groups. Malays had the lowest survival rate of 59.2% followed by Indians (69.5%) and Chinese (73.8%). The overall 5-year survival rate among patients with cervical cancer in Malaysia is relatively good. Age and ethnic groups remain as significant determining factors for cervical cancer survival rate.

Survival Rate of Cancer Patients of National Merit (국가유공자 암환자의 생존율)

  • Park, Un-Je
    • Health Policy and Management
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    • v.31 no.1
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    • pp.35-45
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    • 2021
  • Background: As a descriptive study targeting 2,068 cancer patients as men of national merit in 2013, this study aims to provide the basic data for systematizing the early diagnosis and treatment of cancer by comparatively analyzing the 5-year survival rate. Methods: This study researched the survival of cancer patients through Electronic Medical Record and Patriots-Veterans Qualification Program, targeting 2,068 newly-diagnosed cancer patients verified in five veterans hospitals and consigned management system. This study verified differences between general characteristics of cancer patients as men of national merit and analyzed their survival rate. Results: The cancer patients as men of national merit were super-aged as their average age was 72.5. In the analysis of general characteristics of five major prevalent cancers, there were statistically significant differences according to age, region, cancer diagnostic path, differentiation, diagnostic method, treatment method, SEER stage, and survival period, except for the types of the man of national merit (p<0.001). The whole survival rate of cancer patients as men of national merit was 50%. The 5-year survival rates of predisposing cancers were shown as prostate cancer (79%), colorectal cancer (64%), gastric cancer (57%), liver cancer (32%), and lung cancer (12%). In the cancer diagnostic path, all the predisposing cancers showed the highest survival rate in medical examination. In the treatment method, the surgery showed the highest survival rate. The cancer patients as men of national merit showed a lower survival rate than the general cancer patients of Korea. Conclusion: It would be needed to guarantee the honorable and happy life through health recovery as special treatment of contribution and sacrifice of super-aged men of national merit by increasing the cancer survival rates through regular checkup, early diagnosis, and high-quality treatment system that could have important effects on the survival rate according to the occurrence of cancers.