• Title/Summary/Keyword: mathematical assessment

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Comparison of the Regulatory Models Assessing Off-Site Radiological Dose due to the Routine Releases of Tritium (삼중수소의 환경방출에 따른 주민선량 규제모델의 비교)

  • Hwang W. T.;Kim E. H.;Han M. H.;Choi Y. H.;Lee H. S.;Lee C. W.
    • Proceedings of the Korean Radioactive Waste Society Conference
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    • 2005.06a
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    • pp.464-473
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    • 2005
  • Methodologies of NEWTRIT model, NRC model and AIRDOS-EPA model, which are off-site dose assessment models for regulatory compliance from routine releases of tritium into the environment, were investigated. Using the domestic data, if available, the predictive results of the models were compared. Among them, recently developed NEWTRIT model considers only doses from organically bounded tritium (OBT) due to environmental releases of tritiated water (HTO). A total dose from all exposure pathways predicted from AIRDOS-EPA model was 1.03 and 2.46 times higher than that from NEWTRIT model and NRC model, respectively. From above result, readers should not have an understanding that a predictive dose from NRC model may be underestimated compared with a realistic dose. It is because of that both mathematical models and corresponding parameter values for regulatory compliance are based on the conservative assumptions. For a dose by food consumption predicted from NEWTRIT model, the contribution of OBT was nearly equivalent to that of HTO due to relatively high consumption of grains in Korean. Although a total dose predicted from NEWTRIT model is similar to that from AIRDOS-EPA model, NEWTRIT model may be have a meaning in the understanding of phenomena for the behavior of HTO released into the environment.

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Development of Predictive Growth Model of Imitation Crab Sticks Putrefactive Bacteria Using Mathematical Quantitative Assessment Model (수학적 정량평가모델을 이용한 게맛살 부패균의 성장 예측모델의 개발)

  • Moon, Sung-Yang;Paek, Jang-Mi;Shin, Il-Shik
    • Korean Journal of Food Science and Technology
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    • v.37 no.6
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    • pp.1012-1017
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    • 2005
  • Predictive growth model of putrefactive bacteria of surimi-based imitation crab in the modified surimi-based imitation crab (MIC) broth was investigated. The growth curves of putrefactive bacteria were obtained by measuring cell number in MIC broth under different conditions (Initial cell number, $1.0{\times}10^2,\;1.0{\times}10^3$ and $1.0{\times}10^4$ colony forming unit (CFU)/mL; temperature, $15^{\circ}C,\;20^{\circ}C\;and\;25^{\circ}C$) and applied them to Gompertz model. The microbial growth indicators, maximum specific growth rate constant (k), lag time (LT) and generation time (GT), were calculated from Gompertz model. Maximum specific growth rate (k) of putrefactive bacteria was become fast with rising temperature and fastest at $25^{\circ}C$. LT and GT were become short with rising temperature and shortest at $25^{\circ}C$. There were not significant differences in k, LT and GT by initial cell number (p>0.05). Polynomial model, $k=-0.2160+0.0241T-0.0199A_0$, and square root model, $\sqrt{k}=0.02669$ (T-3.5689), were developed to express the combination effects of temperature and initial cell number, The relative coefficient of experimental k and predicted k of polynomial model was 0.87 from response surface model. The relative coefficient of experimental k and predicted k of square root model was 0.88. From above results, we found that the growth of putrefactive bacteria was mainly affected by temperature and the square root model was more credible than the polynomial model for the prediction of the growth of putrefactive bacteria.

Development of Predictive Growth Model of Listeria monocytogenes Using Mathematical Quantitative Assessment Model (수학적 정량평가모델을 이용한 Listeria monocytogenes의 성장 예측모델의 개발)

  • Moon, Sung-Yang;Woo, Gun-Jo;Shin, Il-Shik
    • Korean Journal of Food Science and Technology
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    • v.37 no.2
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    • pp.194-198
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    • 2005
  • Growth curves of Listeria monocytogenes in modified surimi-based imitation crab (MIC) broth were obtained by measuring cell concentration in MIC broth at different culture conditions [initial cell numbers, $1.0{\times}10^{2},\;1.0{\times}10^{3}\;and\;1.0{\times}10^{4}$, colony forming unit (CFU)/mL; temperature, 15, 20, 25, 37, and $40^{\circ}C$] and applied to Gompertz model to determine microbial growth indicators, maximum specific growth rate constant (k), lag time (LT), and generation time (GT). Maximum specific growth rate of L. monocytogenes increased rapidly with increasing temperature and reached maximum at $37^{\circ}C$, whereas LT and GT decreased with increasing temperature and reached minimum at $37^{\circ}C$. Initial cell number had no effect on k, LT, and GT (p > 0.05). Polynomial and square root models were developed to express combined effects of temperature and initial cell number using Gauss-Newton Algorism. Relative coefficients of experimental k and predicted k of polynomial and square root models were 0.92 and 0.95, respectively, based on response surface model. Results indicate L. monocytogenes growth was mainly affected by temperature and square root model was more effective than polynomial model for growth prediction.

Convolutional Neural Networks for Rice Yield Estimation Using MODIS and Weather Data: A Case Study for South Korea (MODIS와 기상자료 기반 회선신경망 알고리즘을 이용한 남한 전역 쌀 생산량 추정)

  • Ma, Jong Won;Nguyen, Cong Hieu;Lee, Kyungdo;Heo, Joon
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.34 no.5
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    • pp.525-534
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    • 2016
  • In South Korea, paddy rice has been consumed over the entire region and it is the main source of income for farmers, thus mathematical model for the estimation of rice yield is required for such decision-making processes in agriculture. The objectives of our study are to: (1) develop rice yield estimation model using Convolutional Neural Networks(CNN), (2) choose hyper-parameters for the model which show the best performance and (3) investigate whether CNN model can effectively predict the rice yield by the comparison with the model using Artificial Neural Networks(ANN). Weather and MODIS(The MOderate Resolution Imaging Spectroradiometer) products from April to September in year 2000~2013 were used for the rice yield estimation models and cross-validation was implemented for the accuracy assessment. The CNN and ANN models showed Root Mean Square Error(RMSE) of 36.10kg/10a, 48.61kg/10a based on rice points, respectively and 31.30kg/10a, 39.31kg/10a based on 'Si-Gun-Gu' districts, respectively. The CNN models outperformed ANN models and its possibility of application for the field of rice yield estimation in South Korea was proved.

Vegetation Structure and Management Strategies of Glaux maritima var. obtusifolia Community on the Southernmost Distribution Area in Korea (멸종위기 식물인 갯봄맞이 최남단 군락의 식생구조)

  • Lim, Jeong Cheol;Lee, Cheol Ho;Kim, Eui Ju;Choi, Byoung Ki
    • Journal of Wetlands Research
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    • v.20 no.1
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    • pp.1-13
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    • 2018
  • Glaux maritima var. obtusifolia is distributed in very limited areas in South Korea and thus designated and protected as an endangered species. This study aimed to identify the diversity of vegetation in the Dangsa coast wetlands, the southern limit of G. maritima var. obtusifolia and to assess determinants of the vegetation and the importance of habitats. The phytosociological method of the $Z{\ddot{u}}rich-Montpellier$ School was used for vegetation classification and mathematical and statistical analyses were also conducted to analyze environmental factors and their relationship with the vegetation. The results of this study showed that there were 4 vegetation units in the Dangsa coast wetlands: Glaux maritima var. obtusifolia-Triglochin maritimum community (included three subcommunities), Puccinellia nipponica s.l. community, Beckmannia syzigachne-Isachne globosa community and Typha laxmannii-Phragmites communis community. It was also found that major determinants of the vegetation include moisture environment, soil depth, water level disturbance, vegetation height, community structure, etc. Glaux maritima was identified to grow most dominantly in the typicum subassociation of Glaux. maritima var. obtusifolia-Triglochin maritimum community, and the species compositions and dominant situations were observed to be similar to those in the southern limit in Japan, adjacent to South Korea. The assessment results indicated that the Dangsa coastal wetlands have a significant meaning from phytogeographical and syngeographical aspects, and contribute as a shelter for diverse species. It is required to establish conservation strategies to accurately determine the value of the wetlands of the Dangsa coast from various perspectives, and to protect and manage them.

The Application of Fuzzy Logic to Assess the Performance of Participants and Components of Building Information Modeling

  • Wang, Bohan;Yang, Jin;Tan, Adrian;Tan, Fabian Hadipriono;Parke, Michael
    • Journal of Construction Engineering and Project Management
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    • v.8 no.4
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    • pp.1-24
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    • 2018
  • In the last decade, the use of Building Information Modeling (BIM) as a new technology has been applied with traditional Computer-aided design implementations in an increasing number of architecture, engineering, and construction projects and applications. Its employment alongside construction management, can be a valuable tool in helping move these activities and projects forward in a more efficient and time-effective manner. The traditional stakeholders, i.e., Owner, A/E and the Contractor are involved in this BIM system that is used in almost every activity of construction projects, such as design, cost estimate and scheduling. This article extracts major features of the application of BIM from perspective of participating BIM components, along with the different phrases, and applies to them a logistic analysis using a fuzzy performance tree, quantifying these phrases to judge the effectiveness of the BIM techniques employed. That is to say, these fuzzy performance trees with fuzzy logic concepts can properly translate the linguistic rating into numeric expressions, and are thus employed in evaluating the influence of BIM applications as a mathematical process. The rotational fuzzy models are used to represent the membership functions of the performance values and their corresponding weights. Illustrations of the use of this fuzzy BIM performance tree are presented in the study for the uninitiated users. The results of these processes are an evaluation of BIM project performance as highly positive. The quantification of the performance ratings for the individual factors is a significant contributor to this assessment, capable of parsing vernacular language into numerical data for a more accurate and precise use in performance analysis. It is hoped that fuzzy performance trees and fuzzy set analysis can be used as a tool for the quality and risk analysis for other construction techniques in the future. Baldwin's rotational models are used to represent the membership functions of the fuzzy sets. Three scenarios are presented using fuzzy MEAN, AND and OR gates from the lowest to intermediate levels of the tree, and fuzzy SUM gate to relate the intermediate level to the top component of the tree, i.e., BIM application final performance. The use of fuzzy MEAN for lower levels and fuzzy SUM gates to reach the top level suggests the most realistic and accurate results. The methodology (fuzzy performance tree) described in this paper is appropriate to implement in today's construction industry when limited objective data is presented and it is heavily relied on experts' subjective judgment.

MDA Assessment of NaI(Tl), LaBr3(Ce), and CeBr3 Detectors for Freshly Deposited Radionuclides on the Soil (지표면 침적 방사성핵종에 대한 NaI(Tl), LaBr3(Ce) 및 CeBr3 검출기의 MDA 비교 평가)

  • Lee, Jun-Ho;Kim, Bong-Gi;Lee, Dong Myung;Byun, Jong-In
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.17 no.3
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    • pp.321-328
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    • 2019
  • The detection performances of the NaI(Tl), $LaBr_3$(Ce) and $CeBr_3$ scintillation detectors, which can be used to rapidly evaluate the major artificial radionuclides deposited on the soil surface in a nuclear accident or radiological emergency, were compared. Detection performance was assessed by calculating the minimum detectable activity (MDA). The detection efficiency of each detector for artificial radionuclides was semi-empirically determined using mathematical modelling and point-like sources having certified radioactivity. The background gamma-ray energy spectrum for MDA evaluation was obtained from relatively wide and flat grassland, and the MDA values of each detector for the major artificial radionuclides that could be released in nuclear accidents were calculated. As a result, the relative MDA values of each detector regarding surface deposition distribution at normal environmental radiation level were evaluated as high in the order of the NaI(Tl), $LaBr_3$(Ce), and $CeBr_3$ detectors. These results were compared based on each detector's intrinsic and measurement environment background, detection efficiency, and energy resolution for the gamma-ray energy region of the radionuclide of interest.

A Mathematical Programming Method for Minimization of Carbon Debt of Bioenergy (바이오에너지의 탄소부채 최소화를 위한 수학적 계획법)

  • Choi, Soo Hyoung
    • Clean Technology
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    • v.27 no.3
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    • pp.269-274
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    • 2021
  • Bioenergy is generally considered to be one of the options for pursuing carbon neutrality. However, for a period of time, combustion of harvested plant biomass inevitably causes more carbon dioxide in the atmosphere than combustion of fossil fuels. This paper proposes a method that predicts and minimizes the total amount and payback period of this carbon debt. As a case study, a carbon cycle impact assessment was performed for immediate switching of the currently used fossil fuels to biomass. This work points out a fundamental vulnerability in the concept of carbon neutrality. As an action plan for the sustainability of bioenergy, formulas for afforestation proportional to the decrease in the forest area and surplus harvest proportional to the increase in the forest mass are proposed. The results of optimization indicate that the carbon debt payback period is about 70 years, and the carbon dioxide in the atmosphere increases by more than 50% at a maximum and 3% at a steady state. These are theoretically predicted best results, which are expected to be worse in reality. Therefore, biomass is not truly carbon neutral, and it is inappropriate as an energy source alternative to fossil fuels. The method proposed in this work is expected to be able to contribute to the approach to carbon neutrality by minimizing present and future carbon debt of the bioenergy that is already in use.

Exploring Factors Influencing Affective Characteristics in Elementary School Students: Focusing on School Mathematics Education and Social Environment (초등학생의 정의적 특성에 영향을 미치는 요인 탐색: 학교에서의 수학 교육 및 사회적 환경을 중심으로)

  • Kwon, Jeom-Rae;Kwon, Misun
    • Education of Primary School Mathematics
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    • v.26 no.3
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    • pp.199-217
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    • 2023
  • Affective characteristics have been consistently emphasized in mathematics education, but students' confidence or interest in mathematics has not changed significantly. This study analyzes the factors affecting the affective characteristics according to students' academic achievements, which have not been studied so far. The study was surveyed 593 students in the 5th and 6th grades, divided into school mathematics education and social-environmental factors. As a result of the study, students cited 'mathematics class at school' as the factor that had the most influence on their affective characteristics, regardless of academic achievement. Excluding 'mathematics classes at school', upper level students said that 'private education' and 'college entrance exams and jobs', had the most influence on their affective characteristics. Middle level students said that 'assessment at school' and 'private education' had the most influence on their affective characteristics. Lower-level students said that 'school evaluation' and 'mathematics textbook' had the most influence on the affective characteristics. In particular, as the academic achievement level decreased, students' participation in classes decreased rapidly. Most students said that the mathematics content they were learning was too difficult for that reason. Considering these research results, it would be effective to apply methods according to students' academic achievement to some extent in order to improve affective characteristics.

Evaluation of Hazardous Zones by Evacuation Scenario under Disasters on Training Ships (실습선 재난 시 피난 시나리오 별 위험구역 평가)

  • SangJin Lim;YoonHo Lee
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.30 no.2
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    • pp.200-208
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    • 2024
  • The occurrence a fire on a training ship with a large number of people on board can lead to severe casualties. Hence the Seafarers' Act and Safety Life At Sea(SOLAS) emphasizes the importance of the abandon ship drill. Therefore, in this study, the training ship of Mokpo National Maritime University, Segero, which has a large number of people on board, was selected as the target ship and the likelihood and severity of fire accidents on each deck were predicted through the preliminary hazard analysis(PHA) qualitative risk assessment. Additionally, assuming a fire in a high-risk area, a simulation of evacuation time and population density was performed to quantitatively predict the risk. The the total evacuation time was predicted to be the longest at 501s in the meal time scenario, in which the population distribution was concentrated in one area. Depending on the scenario, some decks had relatively high population densities of over 1.4pers/m2, preventing stagnation in the number of evacuees. The results of this study are expected to be used as basic data to develop training scenarios for training ships by quantifying evacuation time and population density according to various evacuation scenarios, and the research can be expanded in the future through comparison of mathematical models and experimental values.