• 산업경영시스템학회지
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• 제25권2호
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• pp.19-26
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• 2002

In this paper a software program is given for food product life (shelf life) estimation. There are many modules of related operations, considering the characteristic of food industry so that users can easily use and understand the software, and we make the related data referenced In data base. In food industry acceleration tests depend on food deterioration differential equations. Based on such equations, etc, this paper suggests a shelf life estimation software program.

• Communications for Statistical Applications and Methods
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• 제27권1호
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• pp.97-108
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• 2020

This paper compares several methods for estimating parameters of normal inverse Gaussian distribution. Ordinary maximum likelihood estimation and the method of moment estimation often do not work properly due to restrictions on parameters. We examine the performance of adjusted estimation methods along with the ordinary maximum likelihood estimation and the method of moment estimation by simulation and real data application. We also see the effect of the initial value in estimation methods. The simulation results show that the ordinary maximum likelihood estimator is significantly affected by the initial value; in addition, the adjusted estimators have smaller root mean square error than ordinary estimators as well as less impact on the initial value. With real datasets, we obtain similar results to what we see in simulation studies. Based on the results of simulation and real data application, we suggest using adjusted maximum likelihood estimates with adjusted method of moment estimates as initial values to estimate the parameters of normal inverse Gaussian distribution.

• 분석과학
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• 제27권3호
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• pp.153-160
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• 2014

세계적으로 석면분석방법에 관한 다양한 연구사례가 발표되고 있는 가운데, 분석방법의 차이에 따른 석면함유물질(ACM, Asbestos Containing Material) 결과에 대한 관심이 대두되고 있다. 본 연구에서는 균질성이 확보된 ACM 시료를 시야평가법(visual estimation method)과 포인트계수법(point counting method)의 분석결과에 대한 비교 평가를 통하여 분석기관 및 분석자의 신뢰성 향상과 더불어 편광현미경 분석의 기초자료를 확보고자 하였다. 석면분석은 정성분석과 정량분석으로 구분하였으며, 석면정량을 위한 방법은 EPA 600-R-93-116의 시야평가법과 포인트계수법으로 총 400지점을 계수하는 방법으로 실시하였다. 먼저 준비된 시료의 균질성을 분산분석을 이용하여 확인한 결과 이상이 없음을 확인하였다. 정성분석의 결과는 백석면과 갈석면으로 확인되었고 정량분석결과는 포인트계수법이 시야평가법과 비교하여 전체적인 석면함유량이 저평가되는 경향과 함께 포인트계수법은 분석과정이 조금 복잡하고 분석시간이 많이 소요되었다.

• 생물환경조절학회지
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• 제31권2호
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• pp.98-103
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• 2022

엽면적의 비파괴적 추정은 잎 절단에 의한 방법에 비해 간단하고 시간을 절약하므로 다양한 원예 작물에 대한 잎 면적 예측 모델이 개발되었습니다. 그러나 딸기 잎 면적 추정에 대한 연구는 제한적이다. 본 연구는 국내산 딸기 5품종('아리향', '죽향', '금실', '매향', '설향')의 3복엽의 잎길이와 폭을 이용한 비선형회귀분석을 통해 잎면적을 예측하기 위해 수행되었다. 실제 잎 면적과 전개식을 통해 추정된 잎 면적의 관계에 대한 결정계수(R²)는 0.923에서 0.973까지 다양하였다. R² 값이 0.96 이상인 '죽향', '설향' 및 '매향' 3 품종의 잎면적은 본 연구에서 개발한 모델을 사용하여 비파괴적으로 예측할 수 있습니다. 반면 묘의 상태가 좋지 못하고 과한 생장을 했던 '아리향'과 '금실'은 각각 0.938, 0.923으로 약간 낮은 R² 값을 보였다. 본 연구에서 개발한 품종별 잎 면적 추정 모델을 Python으로 코딩하여 본 논문에 첨부하였다. 개발된 추정 모델은 많은 딸기 관련 연구에 광범위하게 사용될 수 있습니다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제17권6호
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• pp.69-81
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• 2012

Diverse geostatistical tools such as kriging have been used to estimate the volume and spatial coverage of contaminated soil needed for remediation. However, many approaches frequently yield estimation errors, due to inherent geostatistical uncertainties. Such errors may yield over- or under-estimation of the amounts of polluted soils, which cause an over-estimation of remediation cost as well as an incomplete clean-up of a contaminated land. Therefore, it is very important to use a better estimation tool considering uncertainties arising from incomplete field investigation (i.e., contamination survey) and mathematical spatial estimation. In the current work, as better estimation tools we propose stochastic simulation approaches which allow the remediation volume to be assessed more accurately along with uncertainty estimation. To test the efficiency of proposed methods, heavy metals (esp., Pb) contaminated soil of a shooting range area was selected. In addition, we suggest a quantitative method to delineate the confident interval of estimated volume (and spatial extent) of polluted soil based on the spatial aspect of uncertainty. The methods proposed in this work can improve a better decision making on soil remediation.

• 한국수학교육학회지시리즈A:수학교육
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• 제55권3호
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• pp.317-334
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• 2016

Knowledge and data interpretation on statistical estimation was important to have statistical literacy that current curriculum was said not to satisfy. The author investigated mathematics teachers' MKT on statistical estimation concerning interpretation of confidence interval by using questionnaire and interview. SMK of teachers' confidence was limited to the area of textbooks to be difficult to interpret data of real life context. Most of teachers wrongly understood SMK of interpretation of confidence interval to have influence upon PCK making correction of students' wrong concept. SMK of samples and sampling distribution that were basic concept of reliability and confidence interval cognized representation of samples rather exactly not to understand importance and value of not only variability but also size of the sample exactly, and not to cognize appropriateness and needs of each stage from sampling to confidence interval estimation to have great difficulty at proper teaching of statistical estimation. PCK that had teaching method had problem of a lot of misconception. MKT of sample and sampling distribution that interpreted confidence interval had almost no relation with teachers' experience to require opportunity for development of teacher professionalism. Therefore, teachers were asked to estimate statistic and to get confidence interval and to understand concept of the sample and think much of not only relationship of each concept but also validity of estimated values, and to have knowledge enough to interpret data of real life contexts, and to think and discuss students' concepts. So, textbooks should introduce actual concepts at real life context to make use of exact orthography and to let teachers be reeducated for development of professionalism.

• Journal of Preventive Medicine and Public Health
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• 제55권1호
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• pp.10-18
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• 2022

Disability-adjusted life-year (DALY) estimates may vary according to factors such as the standard life expectancy, age weighting, time preference and discount rate, calculation of disability weights, and selection of the estimation method. DALY estimation methods are divided into the following 3 approaches: the incidence-based approach, the pure prevalence-based approach, and the hybrid approach. These 3 DALY estimation approaches each reflect different perspectives on the burden of disease using unique characteristics, based on which the selection of a suitable approach may vary by the purpose of the study. The Global Burden of Disease studies, which previously estimated DALYs using the incidence-based approach, switched to using the hybrid approach in 2010, while the National Burden of Disease studies in Korea still mainly apply the incidence-based approach. In order to increase comparability with other international burden of disease studies, more DALY studies using the prevalence-based approach need to be conducted in Korea. However, with the limitations of the hybrid approach in mind, it is necessary to conduct more research using a disease classification system suitable for Korea. Furthermore, more detailed and valid data sources should be established before conducting studies using a broader variety of DALY estimation approaches. This review study will help researchers on burden of disease use an appropriate DALY estimation approach and will contribute to enhancing researchers' ability to critically interpret burden of disease studies.

• 한국태양에너지학회 논문집
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• 제23권1호
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• pp.57-67
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• 2003

This study aims to presents Evaluation Method of Green Remodeling that analyze the value of environment through expense, using the method of life cycle cost and life cycle assessment simultaneously. The results of this study are summarized as follows. Evaluation Model developed in this study can convert economical value of environment into cost by integrating. In addition, the model can apply as a useful tool to estimation of economical design alternative as well as quantification of environmental loads and costs. Evaluation Model presented In this study observe energy consumption and the environmental load emission with qualification, it can forecast effect of environmental cost that cost estimation is expected to be added to energy cost rate by being possible. Synthetically, when Estimation Model and computer program that developed in this study is applies to the construction industry; reasonable management of environmental load is convenient at each step of Green Remodeling. In addition, at preliminary design phase, practical use may be possible by reasonable yardstick about various alternatives and improvement of design alternatives likewise by grasping environmental effect.

• Structural Engineering and Mechanics
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• 제23권6호
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• pp.651-674
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• 2006

The fatigue cracks initiate and propagate in the Armored Vehicle Launch Bridge (AVLB) components, especially like the splice doubler angle, splice plate, and bottom chord, due to the cyclic loading by repeated AVLB-launchings and tank-crossings. In this study, laboratory fatigue tests were conducted on six aluminum 2014-T6, four aluminum 7050-T76511, and four ASTM A36 steel compact-tension specimens to evaluate the crack growth behavior of the materials used for the components. The experimental results provide the relationship (Paris Law) between crack growth rate, da/dn, and stress intensity range, ${\Delta}K$, whose material dependent constants C and m can later be used in the life estimation of the components. Finite Element Method (FEM) was used to obtain the stress intensity factor, K, of the components with cracks. Because of the complexity of loading conditions and component geometry, several assumptions and simplifications are made in the FEM modeling. The FEM results, along with the results obtained from laboratory fatigue tests, are then utilized to estimate critical crack length and remaining life of the components.

• Journal of the Korean Data and Information Science Society
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• 제16권4호
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• pp.923-931
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• 2005

The two parameter generalized exponential distribution was recently introduced by Gupta and Kundu (1999). It is observed that the generalized exponential distribution can be used quite effectively to analyze skewed data set. This paper develops the accelerated life test model using generalized exponential distribution and considers maximum likelihood estimation of parameters under the tampered random variable model. To show the performance of proposed maximum likelihood estimates, some simulation will be performed. Using a real data set, an example will be given.