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  • Title/Summary/Keyword: 확률 과정

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Effects of Sterilization and Cultivation Temperatures of Oak Sawdust Medium on Lentinula edodes Hyphal Growth (참나무 톱밥배지의 살균 및 배양온도가 표고 균사생장에 미치는 영향)

  • Koo, Chang-Duck;Lee, Hwa-Yong;Lee, Gwi-Yong
    • Journal of Korean Society of Forest Science
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    • v.101 no.1
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    • pp.77-82
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    • 2012
  • Sterilization of oak sawdust at 65C for Lentinula edodes bed cultivation can be efficient in sterilization facility cost, but its effect on the mushroom production is uncertain due to high contamination probability. The effective conditions for L. edodes hyphal growth in the low temperature sterilized oak sawdust were investigated with combinations of three sterilization temperatures (65C, 100C and 121C) and four cultivation temperatures (15C, 20C, 25C, and 30C). L. edodes inoculation density effect was also tested with 1 cm, 2 cm, and 4 cm distance in the sawdust (4%, 11% and 25% inoculation rate by surface area). L. edodes hyphal growth in the sawdust sterilized at 65C was as much as at those 100C and 121C when the fungus cultured below 25C, but it was greatly reduced when cultured at 30C. And the sawdust medium with 1cm distance inoculation density was fully occupied with L. edodes hyphae, but those with 2~4cm distance inoculation were contaminated by 4~33%. Therefore, we conclude that low temperature sterilized oak sawdust needs to be cultured under 25C after sufficient inoculation by 25% for successful bed cultivation of L. edodes.

Statistical Inference for Process Capability Indices and 6 Sigma Qualify Levels (공정능력지수들과 6 시그마 품질수준에 대한 통계적 추론)

  • Cho, Joong-Jae;Sim, Kyu-Young;Park, Byoung-Sun
    • Communications for Statistical Applications and Methods
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    • v.15 no.3
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    • pp.451-464
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    • 2008
  • Six sigma is the rating that signifies "best in clas", with only 3.4 defects per million units or operations. Higher sigma quality level is generally perceived by customers as improved performance by assigning a correspondingly higher satisfaction score. The process capability indices and the sigma level Zst have been widely used in six sigma industries to assess process performance. Most evaluations on process capability indices focus on point estimates, which may result in unreliable assessments of process performance. In this paper, we consider statistical inference for process capability indices Cp, Cpk and Cpm. Also, we study better testing procedure on assessing sigma level Zst and capability index Cpm, for practitioners to use in determining whether a given process is capable. The proposed method is easy to use and the decision making is more reliable. Whether a process is clearly normal or nonnormal, our bootstrap testing procedure could be applied effectively without the complexity of calculation. A numerical result based on our proposed method is illustrated.

A development of Bayesian Copula model for a bivariate drought frequency analysis (이변량 가뭄빈도해석을 위한 Bayesian Copula 모델 개발)

  • Kim, Jin-Young;Kim, Jin-Guk;Cho, Young-Hyun;Kwon, Hyun-Han
    • Journal of Korea Water Resources Association
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    • v.50 no.11
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    • pp.745-758
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    • 2017
  • The copula-based models have been successfully applied to hydrological modeling including drought frequency analysis and time series modeling. However, uncertainty estimation associated with the parameters of these model is not often properly addressed. In these context, the main purposes of this study are to develop the Bayesian inference scheme for bivariate copula functions. The main applications considered are two-fold: First, this study developed and tested an approach to copula model parameter estimation within a Bayesian framework for drought frequency analysis. The proposed modeling scheme was shown to correctly estimate model parameters and detect the underlying dependence structure of the assumed copula functions in the synthetic dataset. The model was then used to estimate the joint return period of the recent 2013~2015 drought events in the Han River watershed. The joint return period of the drought duration and drought severity was above 100 years for many of stations. The results obtained in the validation process showed that the proposed model could effectively reproduce the underlying distribution of observed extreme rainfalls as well as explicitly account for parameter uncertainty in the bivariate drought frequency analysis.

A Health Risk Assessment of Tributyltin Compounds in Fishes and Shellfishes in Korea. (국내 유통중인 어패류 섭취에 따른 유기주석화합물의 인체 위해성 평가)

  • Choi, Shi-Nai;Choi, Hye-Kyung;Song, Hoon;Oh, Chang-Hwan;Park, Jong-Sei
    • Journal of Food Hygiene and Safety
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    • v.17 no.3
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    • pp.137-145
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    • 2002
  • Tributyltin compounds have been increasingly used in the form of plastic stabilizers, catalytic agents, industrial agricultural biocides, antifouling paint, and pesticides. Among these organotin compounds, large amounts of tributyltin(TBT) and triphenyltin(TPT) have been used as antifouling agents because they have a superior ability to prevent marine organism from being encrusted on ship bottoms and in culturing nets. Environmental pollution by these organotin compounds in the aquatic environment were undertaken. The international maritime Organization's established a provisional tolerable daily intake(TDI) of 1.6[micro]g TBTO/kg/ B.W. The Food and Agiculture Organization (of the United Nations)/world Health Organization's (FAO/WHO) proposed a TDI of 0.5ug TPT/kg BW/d. This study is conducted monitoring of TBT on seafoods in Korea and risk assessment for exposure on TBT in seafoods. Total hazard index(using Reference Dose : 0.3 ug TBTO/kg B.W/day) of intake exposure on seafoods is 0.04 as the 50th percentile, 0.08 as the 95th percentile. This value is estimated by Monte-Carlo simulation using Crystal Ball(Decisioneering Co., 2001).

Quantitative Cyber Security Scoring System Based on Risk Assessment Model (위험 평가 모델 기반의 정량적 사이버 보안 평가 체계)

  • Kim, Inkyung;Park, Namje
    • Journal of the Korea Institute of Information Security & Cryptology
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    • v.29 no.5
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    • pp.1179-1189
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    • 2019
  • Cyber security evaluation is a series of processes that estimate the level of risk of assets and systems through asset analysis, threat analysis and vulnerability analysis and apply appropriate security measures. In order to prepare for increasing cyber attacks, systematic cyber security evaluation is required. Various indicators for measuring cyber security level such as CWSS and CVSS have been developed, but the quantitative method to apply appropriate security measures according to the risk priority through the standardized security evaluation result is insufficient. It is needed that an Scoring system taking into consideration the characteristics of the target assets, the applied environment, and the impact on the assets. In this paper, we propose a quantitative risk assessment model based on the analysis of existing cyber security scoring system and a method for quantification of assessment factors to apply to the established model. The level of qualitative attribute elements required for cyber security evaluation is expressed as a value through security requirement weight by AHP, threat influence, and vulnerability element applying probability. It is expected that the standardized cyber security evaluation system will be established by supplementing the limitations of the quantitative method of applying the statistical data through the proposed method.

Predicting Cooperative Relationships between Engineering Companies in World Bank's ODA Projects (세계은행 공적개발원조사업의 엔지니어링 기업 간 협력관계 예측모델 개발)

  • Yu, Youngsu;Koo, Bonsang;Lee, Kwanhoon;Han, Seungheon
    • Korean Journal of Construction Engineering and Management
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    • v.20 no.6
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    • pp.107-116
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    • 2019
  • Korean construction engineering firms want to pave the way for expansion of overseas markets through the World Bank's Official Development Assistance (ODA) projects as a way to improve their overseas project performance. However, since the World Bank project competes with global companies for limited projects, building partnerships with suitable business partners is essential to gain an upper hand in bidding competition and meet the institutional conditions of the recipient country. In this regard, many network studies have been conducted in the past through Social Network Analysis (SNA), but few have been analyzed based on the process of changes in the network. So, This study collected winning data from the three Southeast Asian countries that ended after the World Bank's ODA project performed smoothly, and established a learning-based link prediction model that reflected the dynamic nature of the network. As a result, the 11 main variables acting on building a cooperative relationship between winning companies were derived and the effect of each variables on the probability value of cooperation between individual links was identified.

1D, 2D interpretation of stream flooding by HEC-RAS and TELEAMC-2D (HEC-RAS, TELEMAC-2D 모형을 이용한 1, 2차원 하천 범람 해석)

  • Sim, Gyu Hyeon;Song, Si Hoon;Lee, Byung Jun
    • Proceedings of the Korea Water Resources Association Conference
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    • 2015.05a
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    • pp.394-394
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    • 2015
  • 급격히 변화하고 있는 산업화와 도시화로 지구 온난화 현상으로 기상이변의 발생빈도가 높아졌고 기후가 불안정하여 예전보다 많은 집중호우가 발생하면서, 홍수로 인한 제내지 침수가 발생되기도 한다. 기후변화로 인한 수재해에 대응하기 위하여 하천 호소 수리 예측 모형의 개선이 필요한 실정이다. 하지만, 자연하천 유역의 강우-유출 상관관계와 지표면 유출현상 및 하도 수리 특성을 자연현상의 복잡성, 강우발생의 시간적 공간적인 발생과정의 임의성, 정확한 해석방법 및 확률 분석에 따르는 불확실성 들을 토대로 단순한 이론과 제한적인 경험공식 등에 의해서 해석, 재현 및 평가를 한다는 것은 매우 어려운 문제이다. 최근 IT 기술의 발전과 더불어, 많은 연구자, 엔지니어들이 기존 수리 수문학적 지식과 IT기술을 융합하여 복잡 다단한 수자원 환경 문제를 해결하고자 한다. 이와 같은 최근 연구 동향에 의거하여, 본 연구에서는 HEC-RAS, TELEMAC-2D 1, 2차원 수리 모형을 연계하여 하천 흐름 분석 및 홍수 범람 해석에 적용하였다. 본 연구에서는 HEC-RAS, TELEMAC 모형을 적용하여 2012년 태풍 '산바(SANBA)'로 인해 홍수 피해를 입은 고령군에 위치한 낙동강 본류 회천 유역(상류 회천교 ~ 하류 도진교)의 하도 내 흐름 분석과 하천 인근 제내지 홍수범람을 예측하였다. 범람해석에 필요한 지형자료를 기초로 하여 각 지형의 조건에 맞게 수치자료를 이용하여 작성하였고, 수자원 정보를 이용하여 유랑, 수위 등 시계열자료를 지류 및 상 하류의 경계조건으로 설정하고, 조도계수 등 하천 기본정보들을 입력하였다. HEC-RAS 모형은 회천교부터 도진교까지 전구간에 대한 종단면과 횡단면별 홍수침수범위 및 홍수위 크기 등 거시적인 1차원 수리해석에 적용하였고, TELEMAC 모형은 HEC-RAS 시뮬레이션 결과를 바탕으로 HEC-RAS에서 나타내기 힘든 2차원 흐름특성, 침수현상 등 일부 범람 구간에 대해 수리해석에 적용하였다. HEC-RAS 시스템은 수공구조물들의 영향과 하천의 영향을 종 횡단면으로 다양한 홍수침수 범위를 1차원으로 나타 낼 수 있으며, TELEMAC 시스템 수리 모의를 통해 얻어진 결과는 유속, 유량, 수심, 하상고 높이 등 2차원으로 나타낼 수 있다. TELEMAC 시스템을 활용한 2차원 분석은 실측자료와 비교적 유사하고 시각, 공간적으로 이해하기 쉽게 표현되므로, 모형 적용성이 우수한 것으로 판단된다. 향후 유역 해석을 위한 수치데이터, 수위, 유량자료를 확보하여 HEC-RAS, TELEMAC 1, 2차원 연계 모형을 적용 한다면, 하천 준설, 하천 구조물 설치, 홍수피해 등 전반적인 하천관리 계획에 활용할 수 있을 것이라 판단된다.

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Development of Computer Code for Simulation of Multicomponent Aerosol Dynamics -Uncertainty and Sensitivity Analysis- (다성분 에어로졸계의 동특성 묘사를 위한 전산 코드의 개발 -불확실성 및 민감도 해석-)

  • Na, Jang-Hwan;Lee, Byong-Whi
    • Nuclear Engineering and Technology
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    • v.19 no.2
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    • pp.85-98
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    • 1987
  • To analyze the aerosol dynamics in severe accidents of LMFBR, a new computer code entitled MCAD (Multicomponent Aerosol Dynamics) has been developed. The code can treat two component aerosol system using relative collision probability of each particles as sequences of accident scenarios. Coagulation and removal mechanisms incorporating Brownian diffusion and gravitational sedimentation are included in this model. In order to see the effect of particle geometry, the code makes use of the concept of density correction factor and shape factors. The code is verified using the experimental result of NSPP-300 series and compared to other code. At present, it fits the result of experiment well and agrees to the existing code. The input variables included are very uncertain. Hence, it requires uncertainty and sensitivity analysis as a supplement to code development. In this analysis, 14 variables are selected to analyze. The input variables are compounded by experimental design method and Latin hypercube sampling. Their results are applied to Response surface method to see the degree of regression. The stepwise regression method gives an insight to which variables are significant as time elapse and their reasonable ranges. Using Monte Carlo Method to the regression model of LHS, the confidence level of the results of MCAD and their variables is improved.

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Determinants Factors Analysis of Job Retention for Injured Workers after Return-to-Work Using Recurrent Event Survival Analysis (산재근로자의 직업복귀 이후 고용유지 영향 요인 : 재발사건생존분석을 중심으로)

  • Han, Ki myung;Lee, Min ah
    • Korean Journal of Social Welfare Studies
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    • v.48 no.4
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    • pp.221-249
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    • 2017
  • This study aims to investigate determinants that affect job retention of injured workers depending upon types of return to work in order to suggest define the intervention priority for those who returned to original works and for those who did not. After constructing explaining variables based on literature reviews, determinants were verified analyzing 1,292 people using Panel Study of Worker's Compensation Insurance(PSWCI) data. The job retention period turned out to be 46.6 months for those who returned to original work and 34.2 month for those who returned to new works. Injured workers who return to new works tend to have more unemployment experiences. As a result of Cox proportional regression analysis, the longer it takes to return to work, the longer both groups tend to retain after the accident. Age, recuperation period, health status, psycho-social rehabilitation, education and occupational training also affect on job retention probability for those who return to new work. Based upon the analyzed result, setting up an adequate duration for return-to-work, intervention for injured workers who experienced vulnerable working condition before the accident and continuous case management after return-to-work are suggested.

Depressive Symptoms of Caregiving Grandmothers in South Korea (손자녀를 돌보는 한국 조모들의 돌봄 특성에 따른 우울 증상)

  • Lee, Ja-kyung;Jang, Soong-nang
    • 한국노년학
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    • v.36 no.3
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    • pp.693-709
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    • 2016
  • This study was to investigate depressive symptoms of caregiving grandmothers in South Korea and related factors focusing on caregiving characteristics. The data were drawn from the fourth wave of Korean Longitudinal Study on Ageing (KLoSA). The study participants were 3,291 grandmothers who had at least one grandchild, and we limited our analysis to 127 grandmothers who had provided care for their grandchild(ren) during the past one year. As for the depressive symptoms, Center for Epidemiological Survey-Depression 10(CES-D 10) short version were applied. Caregiving characteristics including caregiving duration by weeks per year, caregiving hours per week and the number of grandchildren who received grandmother care were examined. A multiple logistic regression was performed to detect association between caregiving characteristics and depressive symptoms while adjusting for general socioeconomic characteristics and health status of caregiving grandmothers. The longer duration of caregiving lowered the depressive symptoms and in contrast, those who spent more hours for providing care to their grandchildren were more exposed to the depressive symptoms. Physical pain significantly increased their depressive symptoms and low income level were more likely to induce depressive symptoms. More detailed studies on grandchild caregiving patterns among grandmothers were needed. Also, tailored support policy and services should be considered to alleviate their burden and depression in the future.