• Title, Summary, Keyword: Population size

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A Study on a New Lifetime allocation Method of Genetic Algorithm with Varying Population Size (개체군 변환 유전자 알고리즘의 새로운 수명 할당 방식에 관한 연구)

  • Kwon, Key-Ho
    • Journal of the Korean Institute of Telematics and Electronics C
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    • v.36C no.1
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    • pp.66-72
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    • 1999
  • In this paper, we suggest a new lifetime allocation method of genetic algorithm with varying population size. This method can control the size of the population according to the fitness values. The population size is stabilized near the neighbourhood of the optimal value. We used the diploidy method in the coding of the chromosomes. Several simulations confirm that the new allocation method can control the size of the population.

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Trend of Population Change and Future Population in Korea - Korean Future in Year 2000; Long Term National Development - (인구변동 추이와 전망 -2000년대를 향한 국가장기발전 구상을 중심으로-)

  • 고갑석
    • Korea journal of population studies
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    • v.8 no.1
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    • pp.87-117
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    • 1985
  • In Principle, the distriction should be understood between projections and forecasts. When the author or user of a projection is willing to describe it as indicating the most likely population at a give date, then he has made a forecast Population change since 1 960 has been reviewed briefly in order to forecast the population of Korea in the year 2,000 which is a leading factor in long term national development plan for which Korea Institute for Population and Health (KIPH) has been participated since 1983. The author of this paper introduced the population forecast prepared for the long term national development plan and an attempt of comparisons with other forecasts such as D.P. Smith's, T. Frejka's, Economic Planning Board's (EPB), UN's and S.B. Lee's was made. Those six forecasts of Korean future population in year 2,000 varried from 48.5 million to 50.0 million due to the base population and assumption of fertility and mortality however the range of total population size is not large enough. Taking four forecasts such as KIPH, EPB, UN, and Lee based on 1980 population census results and latest data of fertility and mortality, KIPH and UN forecast are close in total population size even though there was a slight difference in fertility and mortality assumptions. The smallest size of total population was shown by S.B. Lee (see Table 13) although the difference between KIPH and Lee was approximately one million which is two percent of total population in year 2,000. As a summary of conclusion the author pointed out that one can take anyone of forecasts prepared by different body because size and proportion wise of the Korean population until early I 990s can not be different much and new population projections must be provided by using 1985 population census data and other latest fertility and mortality information coflected by Korea Institute for Population and Health and Economic Planning Board in forth comming year.

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Design of Adaptive Population-size on Bias in Genetic Algorithms (유전자 알고리즘에서 bias에 의한 adaptive한 개체군 크기의 설정)

  • 김용범;오충환
    • Journal of the Society of Korea Industrial and Systems Engineering
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    • v.18 no.36
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    • pp.133-141
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    • 1995
  • One of the problems brought up in the effective execution of genetic algorithms is that if they come under any influences according as the population size is large or small. In the case of small population size the opportunities of premature convergence are increased when the greatly powerful or no good individual is generated during search of the solution space. And searching the solution space in the case of large population size, the difficulties under the execution cause to searching all for one by one individual in every generation applied is limited, this gives the many interruptions to the convergence of final solution. Now this paper gives a suggestion to set up the adaptive population size which could compute the more correct solution and simplify the development of computation performance.

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Preventing Premature Convergence in Genetic Algorithms with Adaptive Population Size (유전자 집단의 크기 조절을 통한 Genetic Algorithm의 조기 포화 방지)

  • 박래정;박철훈
    • Journal of the Korean Institute of Telematics and Electronics B
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    • v.32B no.12
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    • pp.1680-1686
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    • 1995
  • GAs, effective stochastic search algorithms based on the model of natural evolution and genetics, have been successfully applied to various optimization problems. When population size is not large, GAs often suffer from the phenomenon of premature convergence in which all chromosomes in the population lose the diversity of genes before they find the optimal solution. In this paper, we propose that a new heuristic that maintains the diversity of genes by adding some chromosomes with random mutation and selective mutation into population during evolution. And population size changes dynamically with supplement of new chromosomes. Experimental results for several test functions show that when population size is rather small and the length of chromosome is not long, this method is effective.

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An Overview of Bootstrapping Method Applicable to Survey Researches in Rehabilitation Science

  • Choi, Bong-sam
    • Physical Therapy Korea
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    • v.23 no.2
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    • pp.93-99
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    • 2016
  • Background: Parametric statistical procedures are typically conducted under the condition in which a sample distribution is statistically identical with its population. In reality, investigators use inferential statistics to estimate parameters based on the sample drawn because population distributions are unknown. The uncertainty of limited data from the sample such as lack of sample size may be a challenge in most rehabilitation studies. Objects: The purpose of this study is to review the bootstrapping method to overcome shortcomings of limited sample size in rehabilitation studies. Methods: Articles were reviewed. Results: Bootstrapping method is a statistical procedure that permits the iterative re-sampling with replacement from a sample when the population distribution is unknown. This statistical procedure is to enhance the representativeness of the population being studied and to determine estimates of the parameters when sample size are too limited to generalize the study outcome to target population. The bootstrapping method would overcome limitations such as type II error resulting from small sample sizes. An application on a typical data of a study represented how to deal with challenges of estimating a parameter from small sample size and enhance the uncertainty with optimal confidence intervals and levels. Conclusion: Bootstrapping method may be an effective statistical procedure reducing the standard error of population parameters under the condition requiring both acceptable confidence intervals and confidence level (i.e., p=.05).

Asymptotic Distribution in Estimating a Population Size

  • Choi, Ki-Heon
    • Journal of the Korean Data and Information Science Society
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    • v.10 no.2
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    • pp.313-318
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    • 1999
  • Suppose that there is a population of hidden objects of which the total number N is unknown. From such data, we derive an asymptotic distribution.

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Population Dynamics of Symplocarpus renifolius 1. Population Structure and Vegetative Growth (앉은부채 (Symplocarpus renifolius) 개체군의 동태 1.개체군의 구조와 영양생장)

  • Min, Byeong-Mee;Kang, Hyun-Jung
    • The Korean Journal of Ecology
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    • v.17 no.4
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    • pp.453-461
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    • 1994
  • Size class structure and vegetative growth of a perennial herb of the temperate deciduous forests, Symplocarpus renifolius Schott, were studied from 1991 to 1994 in Namhansansung, Kyonggi Province, Korea. The size class structures of leaf number and leaf area per individual followed bell-shape curve, i.e. frequency of middle class was relatively high. The leaf area increased from the late-March to mid-May. At the end of the growing season, leaf area(length X breadth) was proportional to biomass, especially aboveground biomass. The leaf number and leaf area per individual increased at the rate of 0.08 leaf/year and 9.7 $cm^2/year$, respectively. The size of the individuals in large-sized classes, in leaf number and leaf area, decreased in next year, while the size of the individuals in small-sized classes increased. Therefore, it was concluded that the size class structure of S. renifolius population was largely determined by the growth form.

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Effect of an unsampled population on the estimation of a population size (집단 크기 추정에 대한 미표본 집단의 영향)

  • Chung, Yujin
    • The Korean Journal of Applied Statistics
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    • v.33 no.3
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    • pp.347-355
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    • 2020
  • An Isolation-with-Migration (IM) model is used to estimate extant population sizes, the splitting time of populations split away from their common ancestral populations, and migration rates between the extant populations. An evolutionary model such as IM models is estimated by analyzing DNA sequences sampled from the extant populations in the model. When a true model includes an unsampled 'ghost' population without data, the unsampled population is often ignored from the evolutionary model to infer. In this paper, we conduct a simulation study to investigate the effect of an unsampled population on the estimation of the size of the sampled population. When there exists an unsampled population that shares migrations with the sampled population, the size estimation of the sampled population was biased. However, the size estimation was improved if an evolutionary model, including the unsampled population, was estimated.

Optimum Population Projection in Korea: An Environmental Perspective (환경 측면에서 한국의 적정인구 추계)

  • Jeong, Dae-Yuon
    • Korea journal of population studies
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    • v.29 no.1
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    • pp.269-292
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    • 2006
  • The current environmental problem is global, and threatens the very existence of human beings. Many factors have been argued as the causes of environmental problem. The examples include anthroponcentric human perspective on nature, increase in the knowledge on nature, development of technology, economic growth and unequal distribution, and population increase, etc. The scholars who argues population increase have focused on over-population. However, the estimation of optimum population size has not been attempted in terms of environmental carrying capacity. In such a context, this paper aims at estimating optimum population size in South Korea in terms of environmental carrying capacity. The estimation was done from two approaches. One was based on the state of environment, the other was based on 'the desirable state of environment' Koreans expect. The former is termed an objective approach, while the latter is termed an approach based on social consensus. About 47.5 millions were estimated from the former approach, and 48.5 millions from the latter approach. However, optimum population size increase by 50.5 millions if government increase environmental budget to 2.00% among total budget. As such, different optimum population size is estimated according to the values of variables. The most significant variable determining optimum population size is environmental budget, and followed by supply of clean energy. The estimated optimum population size was based on the time-series data from 1993 to 2002. Therefore, time-series data collected from other years will result in different estimation model, and then different optimum population size will be estimated.

A Combination Capture-Recapture and Line Transect Model in Clustered Population

  • Choi, Jin-Sik;Pyong, Nam-Kung
    • Communications for Statistical Applications and Methods
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    • v.6 no.3
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    • pp.729-748
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    • 1999
  • In this paper we present combined estimator of capture-recapture and line transect model using bivariate detection function and detection probability according to objects being in cluster population. Here bivariate detection function use distance and cluster size. The simulation shows that combined estimator approaches the more true value the larger size parameter. Therefore this estimator using the bivariate detection function is more efficient in estimate the population size and density by size parameter.

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