• Journal of the Korean Society of Safety
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• v.32 no.2
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• pp.52-58
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• 2017

One of the most important elements of the management of chemical accident is threat zone estimation of fires, explosions and toxic gas dispersion based on chemical releases. The threat zone estimation is going to be standard of emergency response for the first defender and base line data of off-site risk assesment (hereinafter referred to as "ORA") and risk management plan (hereinafter referred to as "RMP"). Generally, ALOHA form EPA(U.S.) and Kora(from KOREA MINISTRY OF ENVIRONMENT) has been used for the off-site consequence analysis in Korea. However it is hard to predict accurate consequences rapidly in case of emergency. Hydrochloric acid is a multipurpose raw material used in many industrial applications such as chemical, metal and food industries. It is usually treated in concentrations from 10 ~ 35 %, and release accident have occurred frequently. In this study, we have developed a simplified estimating method and equation to calculate threat zone easily in case of emergency due to release accident of hydrochloric acid.

• Korean Journal of Ichthyology
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• v.32 no.2
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• pp.55-62
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• 2020

The Relative weight index is an index for evaluating nutritional condition of fish by calculating a ratio of observed weight to standard weight. The purpose of this study is estimating standard Length-Weight relationships (standard LWRs) to calculate standard weight for application of relative weight index and analyze frequency distribution of relative weight index of 10 freshwater fish in the South Korea. The standard LWRs for each species was calculated by the Length-Weight data sets from 798 times of captures at 141 sites. The correlation of determination (r²) for all species was over 0.9 and values of parameter b were within the expected range according to Froese (2006). We calculated in increments of 10 from 10 to 90 percentile of relative weight index for each species, and it could be used as a standard for quantitative assessment of nutritional condition of freshwater fish.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.16 no.2
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• pp.23-40
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• 2013

The natural environment restoration industry has been newly included in the environment area of engineering technology. Accordingly, the enactment of a standard of estimate for determining the 'Cost plus Fixed Fee' method has become necessary for the implementation and vitalization of natural environment restoration projects. The purpose of this study is to determine the standards for which the prices for engineering projects are calculated with respect to the enactment of an engineering project standard of estimate in the natural environment restoration field. These include the scope of the technological work, standard area, manpower requirements by technical grade that are necessary for carrying out the technological tasks. Relevant laws and regulations, systems and precedent case studies were investigated and analyzed to establish a price calculation standard. The overall results of the analysis were used and applied to questionnaires, public hearings, and expert delphi techniques. The study showed the following results： The scope of the technological work was categorized into 'Biotopes', 'Eco-corridors' and 'Ecological restoration'. The standard area was set up as $1,000m^2$ for 'Biotopes' and $5,000m^2$ for 'Eco-corridors' and 'Ecological restoration'. The manpower requirements by technical grade that are necessary for carrying out the technological tasks were determined. The suitability of the costs, standard area, manpower requirements by technical grade of ordered engineering projects that are determined by applying the standard of estimate for natural environment restoration that may be enacted pursuant to this study may be effectively investigated and analyzed. Moreover, further studies on the calculation of standard prices that can ensure the stability of natural environment restoration projects will be necessary.

• Journal of Korean Society for Quality Management
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• v.42 no.4
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• pp.747-756
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• 2014

Purpose: The purpose of this study is to apply the Bayesian estimation methodology for producing 'Korean Standard -Quality Excellence Index' model and prove the effectiveness of the new approach based on survey data by comparing the current index with the new index produced by Bayesian estimation method. Methods: The 'Korean Standard -Quality Excellence Index' was produced through the collected survey data by Bayesian estimation method and comparing the deviation with two results for confirming the effectiveness of suggested application. Results: The statistical analysis result shows that suggested estimator, that is, empirical Bayes estimator improves the effectiveness of the index with regard to reduce the error under specific loss function, which is suggested for checking the goodness of fit. Conclusion: Considering the Bayesian techniques such as empirical Bayes estimator for producing the quality excellence index reduces the error for estimating the parameter of interest and furthermore various Bayesian perspective approaches seems to be meaningful for producing the corresponding index.

• Journal of Environmental Impact Assessment
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• v.21 no.1
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• pp.161-169
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• 2012

Recently various attempts have been made to apply HSPF model to calculate runoff and diffuse pollution loads of stream and reservoir watersheds. Because the role of standard flow is very important in the water quality modelling of Total Water Pollution Load Management, HSPF was used as a means of estimating standard flow. In this study, BASINS 4.0 and WinHSPF was applied to the Gomakwoncheon watershed, genetic algorithm(GA) and influence coefficient algorithm were used to calibrate the runoff parameters of the WinHSPF. The objective function is the sum of the squares of the normalized residuals of the observed and calculated flow and it is optimized using GA. Estimates of the optimum runoff parameters are made at each iteration of the influence coefficient algorithm. The calibration results showed a relatively good correspondence between the observed and the calculated values. The standard flow(Q275) of the Gomakwoncheon watershed was estimated using the ten years of weather data.

• Journal of Korean Society for Quality Management
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• v.17 no.2
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• pp.81-92
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• 1989

A class of standard optimization techniques to estimate the stationary transition probabilities among states is discussed. With the use of aggregate time series data on employed labor in industrial sectors, the alternative restricted estimates including minimum absolute deviation, unweighted, weighted, generalized inverse, minimum chi-square and maximum likelihood are evaluated and compared. Analytic and numerical results are shown favorably with the viewpoint of the validity and predictive potentiality of model.

• Proceedings of the Korean Statistical Society Conference
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• 2004.11a
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• pp.205-210
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• 2004

A weighted self-tuning robust regression estimator (WSTE) has the high breakdown point for estimating regression parameters such as other well known high breakdown estimators. In this paper, we propose to obtain standard quantities like confidence intervals, and it is found to be superior to the other high breakdown regression estimators when a sample is contaminated

• Journal of the Korean Statistical Society
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• v.30 no.1
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• pp.31-39
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• 2001

For estimating parameters of possibly nonlinear and/or non-stationary seasonal autoregressive(AR) processes, we introduce a new instrumental variable method which use the direction vector of the regressors in the same period as an instrument. On the basis of the new estimator, we propose new seasonal random walk tests whose limiting null distributions are standard normal regardless of the period of seasonality and types of mean adjustments. Monte-Carlo simulation shows that he powers of he proposed tests are better than those of the tests based on ordinary least squares estimator(OLSE).

• Journal of the Korean Data and Information Science Society
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• v.14 no.4
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• pp.853-861
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• 2003

An improved K-means document clustering method has been presented, where a concept vector is manipulated for each cluster on the basis of cosine similarity of text documents. The concept vectors are unit vectors that have been normalized on the n-dimensional sphere. Because the standard K-means method is sensitive to initial starting condition, our improvement focused on starting condition for estimating the modes of a distribution. The improved K-means clustering algorithm has been applied to a set of text documents, called Classic3, to test and prove efficiency and correctness of clustering result, and showed 7% improvements in its worst case.

• Journal of the Korean Statistical Society
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• v.36 no.3
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• pp.397-410
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• 2007

For the two groups data from multivariate binomial distribution, we consider a bootstrap approach to inferring the simultaneous confidence level and its standard error of a collection of the dependent confidence intervals for the difference of proportions with an experimentwise error rate at the a level are presented. The bootstrap method is used to estimate the simultaneous confidence probability for the difference of proportions.