• Title/Summary/Keyword: risk functions

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Parameter estimation of linear function using VUS and HUM maximization (VUS와 HUM 최적화를 이용한 선형함수의 모수추정)

  • Hong, Chong Sun;Won, Chi Hwan;Jeong, Dong Gil
    • Journal of the Korean Data and Information Science Society
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    • v.26 no.6
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    • pp.1305-1315
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    • 2015
  • Consider the risk score which is a function of a linear score for the classification models. The AUC optimization method can be applied to estimate the coefficients of linear score. These estimates obtained by this AUC approach method are shown to be better than the maximum likelihood estimators using logistic models under the general situation which does not fit the logistic assumptions. In this work, the VUS and HUM approach methods are suggested by extending AUC approach method for more realistic discrimination and prediction worlds. Some simulation results are obtained with both various distributions of thresholds and three kinds of link functions such as logit, complementary log-log and modified logit functions. It is found that coefficient prediction results by using the VUS and HUM approach methods for multiple categorical classification are equivalent to or better than those by using logistic models with some link functions.

농식품안전 정책방향

  • Jo, Jang-Yong
    • 한국환경농학회:학술대회논문집
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    • 2009.07a
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    • pp.3-18
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    • 2009
  • It is difficult for consumers to satisfy high safety request with post-management method such as inspection and surveillance, as various changes in-and-out of the country associated with food safety. In terms of food safety problems related to foods, it is crucial to recognize public health and consumer protection and construct pre-preventive Food Control System. A joint committee, FAO/WHO made the following consultations to the National Food Safety System. ${\circ}$ Approach entirely from farm to table ${\circ}$ Get ready for Risk Analysis System ${\circ}$ Secure transparency ${\circ}$ Establish the optimal policy by evaluating the effect of regulation When it comes to summarizing the consultation, it would be accumulated as two key words; "Efficiency" and "Credibility". Whereas the problem of efficiency focuses on precaution rather than post-management, it requires policy option to maximize consumer's benefit by evaluating the cost for the Food Safety Management and its benefit. Also, analyzing risk's character and amount, demanding an optimal means, and introducing scientific analysis system put much value on the stakeholder's communications are procedure's security which can satisfy both "Efficiency" and "Credibility" simultaneously. Especially, it is emphasized here that Risk Assessment need to be separated from Risk Management. This action is a valid means of credibility security throughout improving transparency. A number of nations and organizations have reformed the method of food management passing through reflection and examination of the prior National Food Safety Management since BSE occurred in Britain, 1996. FSA; Food Standard Agency, AFFSA, EFSA, BfR, and FSC are Risk Assessment Organization functionally separated from Risk Management Organization, JECFA, JMCFA, JMPR, JEMRA in Codex charge Risk Assessment internationally. In case of advanced countries excluding several those such as The U.S. and so forth, though these Risk Assessment Organizations are either separated functionally within Risk Management Organization or operated as apart organ, common factors are in which it has independence as Science Base. While securing independence of Risk Assessment Function, it is a tendency Risk Management should be functionally unified into efficiency as well. Though Germany constructs integral Risk Management System of diverse ways according to social and political conditions of each country such as GFOCP, DVFA, SNFA, CFIS and AQIS, there is a key word in the center, "Securing efficiency of Food Safety Management". However our nation has a representative plural;diversified system with The U.S., we took a step forward for unification as empowering policy's generalization;adjustment and Risk Assessment Function by means of enacting the "Food Safety Fundamental Law" in 2008 and establishing the "Food Safety Policy Commission" with private and governmental sectors in the Prime Minister's office. Even though the unification of Risk Management hereby increased, there is the lack of strengthening function of Risk Assessment and securing independence. It needs to be required for the professional committee in Food Safety Policy Commission to develop as a exclusive office of Risk Assessment by separating from a policy decision. Administrative Branches should reinforce feeble functions such as fundamental investigation;research for carrying out Risk Assessment with securing efficiency throughout reassessment of prior Risk Management Means.

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Concentration Response Functions for Particulate Matter related Health Risk Assessment in South Korea (입자상 대기오염물질의 건강 위해성 평가를 위한 국내 농도반응함수 도출)

  • Ha, Jongsik
    • Journal of Environmental Health Sciences
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    • v.43 no.3
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    • pp.202-213
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    • 2017
  • Objectives: HRA (Health Risk Assessment) is an important tool for measuring the health impacts of air pollution. HRA is already being used widely as an important reference for crafting air pollution policies. However, the absence of a domestic CRF (Concentration Response Function) standard, which is a main component for HRA, could cause confusion amongst policy-makers. The purpose of this study is to tabulate a domestic CRF standard for a PM (Particulate Matter)-related HRA. Methods: This study suggested a domestic CRF standard for HRA thorough a literature review. The literature review for meta-analysis was limited to the English language for epidemiological studies published from January 1980 to March 2016. This meta-analysis was conducted by assuming both fixed- and random-effects of CRF. In addition, studies that reported HRA of air pollution for WHO (World Health Organization), the EC (European Commission), and the EPA (Environmental Protection Agency) were reviewed to compare the CRFs of South Korea to the recommended CRFs of WHO, the EC, or the EPA. Additionally, a domestic CRF standard was supplemented by these. Results: Nineteen studies were selected for the CRF for South Korea. Fifty-three CRFs were derived for meta-analysis. CRFs with a standard for PM-related HRA were divided according to the following four criteria: air pollution, exposure characteristics, type of health impact, and age group. Finally, a domestic CRF standard was created comprised of 21 CRFs. Among these, six CRFs were derived from the results of foreign HRA studies. Conclusions: This study is important in that a domestic CRF standard is first suggested. In addition, this study suggests a further area of study for using HRA as a policy tool and a direction of epidemiological study.

Risk Evaluation in FMEA when the Failure Severity Depends on the Detection Time (FMEA에서 고장 심각도의 탐지시간에 따른 위험성 평가)

  • Jang, Hyeon Ae;Yun, Won Young;Kwon, Hyuck Moo
    • Journal of the Korean Society of Safety
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    • v.31 no.4
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    • pp.136-142
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    • 2016
  • The FMEA is a widely used technique to pre-evaluate and avoid risks due to potential failures for developing an improved design. The conventional FMEA does not consider the possible time gap between occurrence and detection of failure cause. When a failure cause is detected and corrected before the failure itself occurs, there will be no other effect except the correction cost. But, if its cause is detected after the failure actually occurs, its effects will become more severe depending on the duration of the uncorrected failure. Taking this situation into account, a risk metric is developed as an alternative to the RPN of the conventional FMEA. The severity of a failure effect is first modeled as linear and quadratic severity functions of undetected failure time duration. Assuming exponential probability distribution for occurrence and detection time of failures and causes, the expected severity is derived for each failure cause. A new risk metric REM is defined as the product of a failure cause occurrence rate and the expected severity of its corresponding failure. A numerical example and some discussions are provided for illustration.

Evaluation of Risk Factors in Water Supply Networks using PROMETHEE and ANP (PROMETHEE와 ANP 기법을 활용한 상수도관망의 위험요소 평가)

  • Hong, Sung-Jun;Lee, Yong-Dae;Kim, Sheung-Kown;Kim, Joong-Hoon
    • IE interfaces
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    • v.19 no.2
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    • pp.106-116
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    • 2006
  • In this study, the priority of risk factors in supplying water through water supply pipeline network was evaluated by PROMETHEE and ANP multi-criteria decision analysis. We chose 'corrosion', 'burst' and 'water pollution' in pipe as major reference criteria and selected eight risk factors to evaluate the priority, and then we compared the results of PROMETHEE with those of ANP. We also analyzed the results of the sensitivity analysis by changing the weights and parameters of preference functions in PROMETHEE. We investigated the possibility of integrating two methods by using the results of ANP as the weights of preference function in PROMETHEE. The priority of risk factors for supplying municipal water which is evaluated by this study may provide basic data to establish a contingency plan for accidents, or to establish the specific emergency response procedures.

A Meta-analysis of the Variables related to Depression in Korean Patients with a Stroke (한국 뇌졸중 환자의 우울관련 변인에 관한 메타분석)

  • Park, Eun-Young;Shin, In-Soo;Kim, Jung-Hee
    • Journal of Korean Academy of Nursing
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    • v.42 no.4
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    • pp.537-548
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    • 2012
  • Purpose: The purpose of this study was to use meta-analysis to evaluate the variables related to depression in patients who have had a stroke. Methods: The materials of this study were based on 16 variables obtained from 26 recent studies over a span of 10 years which were selected from doctoral dissertations, master's thesis and published articles. Results: Related variables were categorized into sixteen variables and six variable groups which included general characteristics of the patients, disease characteristics, psychological state, physical function, basic needs, and social variables. Also, the classification of six defensive and three risk variables group was based on the negative or positive effect of depression. The quality of life (ES=-.79) and acceptance of disability (ES=-.64) were highly correlated with depression in terms of defensive variables. For risk variables, anxiety (ES=.66), stress (ES=.53) showed high correlation effect size among the risk variables. Conclusion: These findings showed that defensive and risk variables were related to depression among stroke patients. Psychological interventions and improvement in physical functions should be effective in decreasing depression among stroke patients.

Some Theoretical Foundations on the Necessities and Functions of Global Electronic Transactions Act (전자무역 활성화를 위한 글로벌 전자무역거래법의 요건과 역할기능의 이론적 기초)

  • Kim, Ki-Sun
    • THE INTERNATIONAL COMMERCE & LAW REVIEW
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    • v.17
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    • pp.129-146
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    • 2002
  • The electronic technology development have occurred in the face of existing legal barriers to legal efficacy of computer information goods, and the liberating promise of electronic transactions cannot fully realized unless there is predictability in the legal rules that govern such transactions. This study analyzes some theoretical fundamentals of the Act. First, it proposes that the Act clarify and set forth uniform legal principles applicable to computer information transactions. Secondly, it suggests that if the individual is risk averse, the acceptance set for electronic transactions will be a convex set, and that the application of the Act will make the acceptance set more expanded by lowering the probability of conflicts and by downsizing the risk averness. Thirdly, it also suggest that through the mothod of contingent commodities analysis, the application of the Act by means of its restricted regulations will give more expected utility than the absence of the Act. Fourthly, it derives some implications that the degree of legitimate restriction will be affected by the objective risk inherent to the electronic transactions, and the individual's subjective risk-averseness. Finally, it concludes that harmonization of restriction and protection of individual's rights in electronic transaction process will be a necessary condition for more efficient body of law from the law-economic perspectives.

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Quality of Life, Frailty and Depression in Elderly in Rural Area (일부 농촌 지역 노인의 허약수준, 우울, 건강 관련 삶의 질)

  • Kang, Hee Gyoung
    • Journal of Korean Academy of Rural Health Nursing
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    • v.12 no.1
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    • pp.13-27
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    • 2017
  • Purpose: The purpose of this study is to identify health-related factors, especially for the elderly who are subject to visiting health care at vulnerable populations. Methods: Tools were Guide to Community Integrated Health Promotion Project 2016, Visit Health Care Health Interview Survey, measures of physical function, motor skills, composite mobility, BMI, and subjective fitness levels. Depression was measured with the Short Results: Older elders living alone were more vulnerable than those with living others. Elders with less education showed greater weakness but the difference was not significant. Average scores for frailty were 2.21 (healthy group), 7.66 (high-risk group) and 15.69 (frail group). Scores based on weakness level differed significantly with the exception of nutrition. Nine out of 10 elders in disadvantaged areas were in the frail group or at high risk. Conclusion: Results support the goal to maintain/improve physical/mental functions through individual management of high-risk/frail older adults at risk of becoming infirm. It is imperative to implement a public health care delivery system to ensure programs are operated effectively and personalized.

Development of Web-based Design Review System for Reliability and Safety Knowledge Management

  • Otsuka, Yuichi;Yukawa, Takashi;Mutoh, Yoshiharu
    • International Journal of Safety
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    • v.9 no.2
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    • pp.22-28
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    • 2010
  • This paper describes a web-based design review system as a knowledge management system relating reliability and safety system design. Since people's consciousness for safety and security become sensitive and increases the need of establishing a proactive prevention method for internal failures and relating risks in products. It also means that prevailing tacit knowledge in retired workers, in order to transform them to be easily used to support new system development, become more important. When considering safety and reliability design, at least two data sheet are necessary; Failure Modes and Effects Analyses (FMEA) and Risk Assessment (RA). These two data are practically made separately. However, it includes the concerns that a risk by failures during long-term use may not be noticed. To overcome this insufficiency, a support tool for integrating reliability evaluation and risk assessment data simultaneously is expected to be revealed. The authors have then developed a web-based design review system for reliability and safety system design. The system include various profitable functions; making FMEA and RA sheet, retrieving past data sheet for engineering change management and new product development and web-based discussion to increase the efficiency of discussion. The system is applied to one practical development works in order to demonstrate its effectiveness that is to be made clear by interviewing user's qualitative comment.

TREATING UNCERTAINTIES IN A NUCLEAR SEISMIC PROBABILISTIC RISK ASSESSMENT BY MEANS OF THE DEMPSTER-SHAFER THEORY OF EVIDENCE

  • Lo, Chung-Kung;Pedroni, N.;Zio, E.
    • Nuclear Engineering and Technology
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    • v.46 no.1
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    • pp.11-26
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    • 2014
  • The analyses carried out within the Seismic Probabilistic Risk Assessments (SPRAs) of Nuclear Power Plants (NPPs) are affected by significant aleatory and epistemic uncertainties. These uncertainties have to be represented and quantified coherently with the data, information and knowledge available, to provide reasonable assurance that related decisions can be taken robustly and with confidence. The amount of data, information and knowledge available for seismic risk assessment is typically limited, so that the analysis must strongly rely on expert judgments. In this paper, a Dempster-Shafer Theory (DST) framework for handling uncertainties in NPP SPRAs is proposed and applied to an example case study. The main contributions of this paper are two: (i) applying the complete DST framework to SPRA models, showing how to build the Dempster-Shafer structures of the uncertainty parameters based on industry generic data, and (ii) embedding Bayesian updating based on plant specific data into the framework. The results of the application to a case study show that the approach is feasible and effective in (i) describing and jointly propagating aleatory and epistemic uncertainties in SPRA models and (ii) providing 'conservative' bounds on the safety quantities of interest (i.e. Core Damage Frequency, CDF) that reflect the (limited) state of knowledge of the experts about the system of interest.