• Industrial Engineering and Management Systems
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• v.12 no.1
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• pp.46-50
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• 2013

In insurance statistics, the sum of homogeneous insurance is often needed. The sum is called individual risk model which is a fundamental model in risk analysis for insurance. This paper first presents an individual risk model based on the uncertainty theory. Then its uncertainty distribution is provided. Finally, its arithmetic is shown by a numerical example.

• Journal for History of Mathematics
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• v.25 no.1
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• pp.1-13
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• 2012

Possibility theory is a kind of mathematics of uncertainty for handling incomplete information. In this paper, we discuss vagueness and randomness as some causes of uncertainty and we introduce the possibility theory as a way of dealing with uncertainty, comparing it with the probability theory.

• Journal of the Korean Institute of Intelligent Systems
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• v.1 no.2
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• pp.4-45
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• 1991

Measures of two types of uncertainty that coexist in the Dempster-Shafer theory are overivewed. A measure of one type of uncertainty, which expresses nonspecificity of evidential claims, is well justified on both intuitive and mathermatical grounds. Proposed measures of the other types of uncertainty, which attempt to capture conflicts among evidential claims, are shown to have some deficiencies. To alleviate these deficiencies, a new measure is proposed. This measure, which is called a measure of discord, is not only satisfactory on intuitive grounds, but has alos desirable mathematical properties. A measure of total uncertainty, which is defined as the sum of nonspecificity and discord, is also discussed. The paper focuses on conceptual issues. Mathematical properties of the measure of idscord are only stated ; their proofs are given in a companion paper.

• Nuclear Engineering and Technology
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• v.40 no.5
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• pp.327-348
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• 2008

A risk-informed regulatory approach implies that risk insights be used as supplement of deterministic information for safety decision-making purposes. In this view, the use of risk assessment techniques is expected to lead to improved safety and a more rational allocation of the limited resources available. On the other hand, it is recognized that uncertainties affect both the deterministic safety analyses and the risk assessments. In order for the risk-informed decision making process to be effective, the adequate representation and treatment of such uncertainties is mandatory. In this paper, the risk-informed regulatory framework is considered under the focus of the uncertainty issue. Traditionally, probability theory has provided the language and mathematics for the representation and treatment of uncertainty. More recently, other mathematical structures have been introduced. In particular, the Dempster-Shafer theory of evidence is here illustrated as a generalized framework encompassing probability theory and possibility theory. The special case of probability theory is only addressed as term of comparison, given that it is a well known subject. On the other hand, the special case of possibility theory is amply illustrated. An example of the combination of probability and possibility for treating the uncertainty in the parameters of an event tree is illustrated.

• Child Health Nursing Research
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• v.4 no.2
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• pp.207-220
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• 1998

The purpose of this study was to build a substantive theory about the experience of the maternal uncertainty in childhood chronic illness. The qualitative research method used was grounded theory. The interviewees were 12 mothers who have cared for a child who had chronic illness. The data were collected through in-depth interviews with audiotape recording done by the investigator over a period of nine months. The data were analyzed simutaneously by a constant comparative method in which new data were continuously coded into categories and properties according to Strauss and Corbin's methodology. The 34 concepts were identified as a result of analyzing the grounded data. Ten categories emerged from the analysis. The categories were lack of clarity, unpredictability, unfamiliarity, negative change, anxiety, devotion normalization and burn-out. Causal conditions included : lack of clarity, unpredictability, unfamiliarity and change ; central phenomena : anxiety, being perplexed ; context. seriousness of illness, support ; intervening condition : belief action/interaction strategies devotion, overprotection ; consequences : normalization, burn-out. These categories were synthesized into the core concept-anxiety. The process of experiencing uncertainty was 1) Entering the world of uncertainty, 2) Struggling in the tunnel of uncertainty, 3) Reconstruction of the situation of uncertainty. Four hypotheses were derived from the analysis : (1) The higher the lack of clarity, unpredictability, unfamiliaity, change, the higher the level of uncertainty (2) The more serious the illness and the less the support, the higher the level of uncertainty. (3) The positive believes will influence the devoted care and normalization of the family life. Through this substantive theory, pediatric nurses can understand the process of experiencing maternal uncertainty in childhood chronic illness. Further research to build substantive theories to explain other uncertainties may contribute to a formal theory of how normalization is achieved in the family with chronically ill child.

• Ocean Systems Engineering
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• v.6 no.2
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• pp.191-201
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• 2016

Stern bearing is a key component of marine propulsion plant. Its environment is diverse, working condition changeable, and condition severe, so that stern bearing load is of strong time variability, which directly affects the safety and reliability of the system and the normal navigation of ships. In this paper, three affecting factors of the stern bearing load such as hull deformation, propeller hydrodynamic vertical force and bearing wear are calculated and characterized by random theory. The uncertainty mathematical model of stern bearing load is established to research the relationships between factors and uncertainty load of stern bearing. The validity of calculation mathematical model and results is verified by examples and experiment yet. Therefore, the research on the uncertainty load of stern bearing has important theoretical significance and engineering practical value.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.27 no.6
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• pp.605-613
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• 2014

Epistemic uncertainty, the lack of knowledge, is often more important than aleatory uncertainty, variability, in estimating reliability of a system. While the probability theory is widely used for modeling aleatory uncertainty, there is no dominant approach to model epistemic uncertainty. Different approaches have been developed to handle epistemic uncertainties using various theories, such as probability theory, fuzzy sets, evidence theory and possibility theory. However, since these methods are developed from different statistics theories, it is difficult to interpret the result from one method to the other. The goal of this paper is to compare different methods in handling epistemic uncertainty in the view point of calculating the probability of failure. In particular, four different methods are compared; the probability method, the combined distribution method, interval analysis method, and the evidence theory. Characteristics of individual methods are compared in the view point of reliability analysis.

• Journal of the military operations research society of Korea
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• v.23 no.2
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• pp.45-71
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• 1997

There has been considerable research recently on uncertainty handling in the fields of artificial intelligence and knowledge-based system. Various numerical and non-numerical methods have been proposed for representing and propagating uncertainty in knowledge-based system. The Bayesian method, the Dempster-Shafer's Evidence Theory, the Certainty Factor model and the Fuzzy Set Theory are most frequently appeared in the knowledge-based system. Each of these four methods views uncertainty from a different perspective and propagates it differently. There is no single method which can handle uncertainty properly in all kinds of knowledge-based systems' domain. Therefore a knowledge-based system will work more effectively when the uncertainty handling method in the system fits to the system's environment. This paper proposed a framework for selecting proper uncertainty handling methods in knowledge-based system with respect to characteristics of problem domain and cognitive styles of experts. A schema with strategic/operational and unstructured/structured classification is employed to differenciate domain. And a schema with systematic/intuitive and preceptive/receptive classification is employed to differenciate experts' cognitive style. The characteristics of uncertainty handling methods are compared with characteristics of problem domains and cognitive styles respectively. Then a proper uncertainty handling method is proposed for each category.

• Industrial Engineering and Management Systems
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• v.11 no.2
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• pp.176-182
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• 2012

This paper presents a new approach to risk comparison in uncertain environment. Based on the uncertainty theory, some uncertain risk measures and risk comparison rules are proposed. Afterward the bridges are built between uncertain risk measures and risk comparison rules. Finally, several comparable examples are given.

• Korean Journal of Adult Nursing
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• v.15 no.1
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• pp.146-153
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• 2003

연구목적: 본 연구는 대표적인 중간범위 간호이론인 Mishel의 Uncertainty in Illness모델에 관한 연구문헌 고찰이다. 기존의 간호이론에 근거해서 새로운 간호연구가 시행되고 있으며, 이러한 연구들의 결과는 또한, 근거이론을 지지 및 수정보완을 통해서 간호이론의 타당성과 유용성을 강화해왔다. Mishel의 모델에 근거한 불확실감에 관한 연구의 수행에 앞서, 근거이론에 관한 현지식의 상태와 부족한 영역을 탐구하여, 이에 기여할 수 있는 연구계획을 수립하는데 문헌고찰의 주요한 목적이 있다. 연구방법: 본 문헌고찰은 중간범위 간호이론인 Mishel's Uncertainty in Illness에서의 주요 개념간의 관계에 대해서 선행연구 결과를 토대로 분석하였다. 연구결과: 불확실감의 선행요소들(antecedents)과 불확실감, 불확실감의 평가(appraisal of uncertainty), 불확실감 모델내에서 건강 통제위(health locus of control)의 역할, 및 불확실감의 결과, 적응(adaptation)에 관하여 고찰하였다. 결론: 문헌고찰 결과로서, 불확실감 이론에 관한 현지식의 상태를 확인하였고 이 이론의 타당성과 유용성을 확인하기 위한 추후연구에 대한 방향도 제언되었다.