• Title/Summary/Keyword: population trend

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Efficient Estimation of the Mean for Populations with a Linear Trend : An Extension of Systematic Sampling (선형추세를 갖는 모집단에 대한 효율적인 모평균 추정 : 계통추출의 확장)

  • 김혁주;석은양
    • The Korean Journal of Applied Statistics
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    • v.13 no.2
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    • pp.457-476
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    • 2000
  • In this study, we have proposed a sampling method and an estimation method for efficiently estimating the mean of a population which has a linear trend. These methods involve drawing a sample by the so-called "centered balanced systematic sampling", which is an extension of systematic sampling, and then estimating the population mean with an adjusted estimator, not with the sample mean itself. We used the concept of interpolation in determining the adjusted estimator.\Ve compared the efficiency of the proposed estimator with those of the estimators from existing methods, under the expected mean square error criterion based on the infinite superpopulation model introduced by Cochran(1946). The proposed method is for use in the case when the sample size n(2 5) is an odd number and k(the reciprocal of the sampling fraction) is an even number. A good result was also obtained in an example using computer simulation. simulation.

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Early Stage Oral Tongue Cancer among Non-Tobacco Users - An Increasing Trend Observed in a South Indian Patient Population Presenting at a Single Centre

  • Krishnamurthy, Arvind;Ramshankar, Vijayalakshmi
    • Asian Pacific Journal of Cancer Prevention
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    • v.14 no.9
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    • pp.5061-5065
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    • 2013
  • Background: Oral tongue squamous cell carcinoma (OTSCC) is the most common cancer diagnosed within the oral cavity worldwide. Many studies in India report OTSCC ranking among the top two most common subsites within the oral cavity. India is often labeled the oral cancer capital of the world. The incidence of tongue cancers in the population-based cancer registry (PBCR) of Chennai is showing an increasing trend. A majority of the oral cavity cancers (85%) in our cancer center present in advanced stages (III and IV). In contrast, early tongue cancers (stages I and II) constitute nearly 45% of all OTSCCs. Aim: The aim of this study was to analyze the clinical profile and epidemiological trends in our early stage tongue cancer patients with an emphasis on tobacco and alcohol habits. Materials and Methods: This retrospective analysis was based on a prospectively collected database of 458 consecutive early stage OTSCC in-patients at a tertiary care oncology centre in Chennai between 1995 and 2008. Results: Our study suggests that the earlier trends have clearly changed whereby nearly half of our patients are now never-tobacco users. The findings of the study indicate that a majority of the patients were never alcohol users (86.4%) and nearly half of them were never tobacco users (49.3%), and they had the best survival outcomes. This increasing trend of OTSCC among non-tobacco users is in contrast to our earlier experience of tongue cancer more than five decades ago.The median age of patients in our study was 53.3 years; the male to female ratio was approximately 2:1. The median follow up for the 458 patients was 53 months. Conclusions: Our study importantly as well as interestingly shows a conspicuous absence of association with the traditional risk factors, tobacco and alcohol.

Trend and prediction of the Ecological Footprint in Korea (우리나라 생태발자국(EF) 추이와 예측)

  • Yeo, Min Ju;Kim, Yong Pyo
    • Journal of Environmental Impact Assessment
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    • v.23 no.5
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    • pp.364-378
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    • 2014
  • Ecological Footprint (EF) in Korea has increased steeply over the past 50 years and, thus, the overshoot. It has been known that the main causes of the overshoot are population growth and the increase of the consumption intensity per person. In this study, the EF trend in Korea is analyzed for the past 50 years and it is found the major cause of the rapid increase of EF in Korea is the increase of the consumption intensity per person. Among the sectors of the consumption, Carbon Footprint (CF) from the energy consumption and Grazing Land Footprint and Fishing Grounds Footprint from the protein consumption are the major players for the increase. It is also found that if current trend of the EF per person would be maintained until 2060, EF in Korea would be expected to increase also continuously, despite of the decrease of the population from 2031. Therefore, the direction of the environmental management should be considered for inducing the change of the individual consumption patterns and the behavioral changes.

The Analysis of Older Driver's Traffic Accident Characteristic at Express-way using Logit model (로짓모델을 이용한 고령운전자 고속도로 교통사고 특성 분석 연구)

  • Park, Jun-Tae;Kim, Young-Suck;Lee, Soo-Beom
    • International Journal of Highway Engineering
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    • v.11 no.4
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    • pp.1-7
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    • 2009
  • Traffic accident by aging drivers is expected to be on the rise rapidly as the number of aging drivers is rising along with the aging trend being progressed. In this study, traffic accident features depending on the classification of aging population and non aging one was evaluated. As a result of this evaluation, effect factors influencing over the aging population was found to be expressed differently from that of the non aging one. Odds ratio between the aging population and non aging one was evaluated through logit model and a model with potential accident probability of the aged drivers was developed. Accident risk of the aged drivers under the condition of curved road, cutting section and moistured road was revealed to be higher than that of the non aging population.

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Genetic diversity and population structure of rice accessions from South Asia using SSR markers

  • Cui, Hao;Moe, Kyaw Thu;Chung, Jong-Wook;Cho, Young-Il;Lee, Gi-An;Park, Yong-Jin
    • Korean Journal of Breeding Science
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    • v.42 no.1
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    • pp.11-22
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    • 2010
  • The population structure of a domesticated species is influenced by the natural history of the populations of its pre-domesticated ancestors, as well as by the breeding system and complexity of breeding practices implemented by humans. In the genetic and population structure analysis of 122 South Asia collections using 29 simple sequence repeat (SSR) markers, 362 alleles were detected, with an average of 12.5 per locus. The average expected heterozygosity and polymorphism information content (PIC) for each SSR locus were 0.74 and 0.72,respectively. The model-based structure analysis revealed the presence of three clusters with the 91.8% (shared > 75%) membership, with 8.2% showing admixture. The genetic distances of Clusters 1-3 were 0.55, 0.56, and 0.68, respectively. Polymorphic information content followed the same trend (Cluster 3 had the highest value and Cluster 1 had smallest value), with genetic distances for each cluster of 0.52, 0.52, and 0.65, respectively. This result could be used for supporting rice breeding programs in South Asia countries.

Evidence for the Luminosity Evolution of Type Ia Supernovae from the Ages of Early-type Host Galaxies

  • Lee, Young-Wook;Kang, Yijung;Kim, Young-Lo;Lim, Dongwook;Chung, Chul
    • The Bulletin of The Korean Astronomical Society
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    • v.38 no.2
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    • pp.56.1-56.1
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    • 2013
  • Supernovae type Ia (SNe Ia) cosmology is providing the only direct evidence for the presence of dark energy. This result is based on the assumption that the look-back time evolution of SNe Ia luminosity, after light-curve shape correction, would be negligible. However, the most recent compilation of SNe Ia data shows systematic difference in the Hubble residual (HR) between the E and Sd/Irr galaxies, indicating that the light-curve fitters used by the SNe Ia community cannot quite correct for a large portion of the population age effect. In order to investigate this possibility more directly, we have obtained low-resolution spectra for 30 nearby early-type host galaxies. This data set is used to estimate the luminosity-weighted mean ages and metallicities of host galaxies by employing the population synthesis models. We found an interesting trend between the host galaxy age and HR, in the sense that younger galaxies have positive residuals (i.e., light-curve corrected SNe Ia luminosity is fainter). This result is rather independent of the choice of the population synthesis models employed. Taken at face value, this age (evolution) effect can mimic a large fraction of the HR used in the discovery of the dark energy. This result is significant at 1.4 - 3 sigma levels, depending on the light curve fitters adopted, and further observations and analyses are certainly required to confirm the trend reported here.

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Analysis of Kimchi, vegetable and fruit consumption trends among Korean adults: data from the Korea National Health and Nutrition Examination Survey (1998-2012)

  • Kim, Eun-Kyung;Ha, Ae-Wha;Choi, Eun-Ok;Ju, Se-Young
    • Nutrition Research and Practice
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    • v.10 no.2
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    • pp.188-197
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    • 2016
  • BACKGROUND/OBJECTIVES: The purpose of this study is to analyze daily kimchi, vegetable and fruit consumption by general characteristics and vegetable and fruit consumption from 1998 to 2012 by the Korean population based on the data of the KNHANES (Korea National Health and Nutrition Examination Survey). SUBJECTS/METHODS: This study is based on the 1998-2012 KNHNES. Analysis data on 54,700 subjects aged 19 years and older were obtained from health behavior interviews and the 24-hour dietary recall method. RESULTS: Daily kimchi consumption and portion size of kimchi decreased significantly from 1998 to 2012 (adjusted P for trend < 0.0001). Meanwhile, daily consumption of both non-salted vegetable and fruit with and without kimchi did not significantly change between 1998 and 2012. Reduced consumption of kimchi, non-salted vegetable, and fruit was observed for both genders as well as daily meal episodes and cooking locations. Male and female subjects with insufficient non-salted vegetable and fruit intake were increased 1.4 times and 1.3 times, respectively, in 2012 than 1998. All subjects consumed at least 400 g/day of non-salted vegetable, fruit, and kimchi in each survey year, although they consumed insufficient amounts (< 400 g/day) of non-salted vegetable and fruit without kimchi. CONCLUSIONS: Since Koreans generally consume high amounts of fermented vegetables, including kimchi, total vegetables and fruit. Consumption of these foods by the Korean adult population reached 400 g, which is the recommended intake of the WCRF/AICR. Based on this result, it is necessary to promote consumption of kimchi in the Korean population and research the development of low sodium kimchi in the future.

A Statistical Homogeneity Analysis of Seoul Rainfall using Bootstrap (Bootstrap 기법을 이용한 서울지점 강우자료의 통계적 동질성 분석)

  • Hwang, Seok-Hwan;Kim, Joong-Hoon;Yoo, Chul-Sang;Jung, Sung-Won;Yoo, Do-Guen
    • Journal of Korea Water Resources Association
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    • v.42 no.10
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    • pp.795-807
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    • 2009
  • In this study, homogeneity analysis was performed between rainfall observation data set of Chukwooki (CWK) and rainfall observation data set of modern rain gage (MRG) using Bootstrap method. Since traditional statistical homogeneity test method are validated only when distribution of their population is known, meteorological data which their statistical distributions of population are complicated were difficult to verify the homogeneity and there were plenty of room for doubt for their statistical significance using historical method. In this reason, in this study homogeneity test was evaluated between two data sets using bootstrap method which is not necessary to infer distribution of population. The test results show that there was an statistical homogeneity between CWK and MRG except for slight impact of climatical trend.

A Change of Private Security Labor Market and Countermeasures by Population Aging (인구고령화에 따른 민간경비 노동시장 변화와 대응방안)

  • Park, Su Hyeon;Bae, Du Yeol
    • Convergence Security Journal
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    • v.15 no.1
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    • pp.11-18
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    • 2015
  • Our country is a nation accomplished the economic growth and democracy at the same time on the bases of human capitals. However, the laborers as human capitals are aging as well due to the population aging. These aging phenomena are impacting on our country's economy, society, and through the culture. It seems to increase the proportion of the elderly in the labor market of private security caused by continuously increasing the number of elderly employees in long-term trend and their preferences for the security services. These changes of labor market trend may result various problems including relevant laws and systems, the changes of laborers' ability, increase of crimes and so on. To prevent such potential problems, firstly the limits of maximum working hours of elderly private guards have to be set up, and the rest times for them must be secured. Furthermore, the declines of elderly laborers' abilities have to be reduced through the systematic educations relevant to their jobs to cover the rapidly declining elderly laborers' physical abilities. Lastly, the increase of crimes should be reduced through the education contents to be able to arouse their attentions by extending the time of job training and informing of criminal cases.

Epidemiology of Oral Cancer in Asia in the Past Decade- An Update (2000-2012)

  • Rao, Sree Vidya Krishna;Mejia, Gloria;Roberts-Thomson, Kaye;Logan, Richard
    • Asian Pacific Journal of Cancer Prevention
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    • v.14 no.10
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    • pp.5567-5577
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    • 2013
  • The prevalence of oral cancers (OC) is high in Asian countries, especially in South and Southeast Asia. Asian distinct cultural practices such as betel-quid chewing, and varying patterns of tobacco and alcohol use are important risk factors that predispose to cancer of the oral cavity. The aim of this review is to provide an update on epidemiology of OC between 2000 and 2012. A literature search for this review was conducted on Medline for articles on OC from Asian countries. Some of the articles were also hand searched using Google. High incidence rates were reported from developing nations like India, Pakistan, Bangladesh, Taiwan and Sri Lanka. While an increasing trend has been observed in Pakistan, Taiwan and Thailand, a decreasing trend is seen in Philippines and Sri Lanka. The mean age of occurrence of cancer in different parts of oral cavity is usually between 51-55 years in most countries. The tongue is the leading site among oral cancers in India. The next most common sites in Asian countries include the buccal mucosa and gingiva. The 5 year survival rate has been low for OC, despite improvements in diagnosis and treatment. Tobacco chewing, smoking and alcohol are the main reasons for the increasing incidence rates. Low socioeconomic status and diet low in nutritional value lacking vegetables and fruits contribute towards the risk. In addition, viral infections, such as HPV and poor oral hygiene, are other important risk factors. Hence, it is important to control OC by screening for early diagnosis and controlling tobacco and alcohol use. It is also necessary to have cancer surveillance at the national-level to collect and utilise data for cancer prevention and control programs.