scholarly journals Posbist Reliability Theory for Typical Systems with Multicomponents

2020 ◽  
Vol 2020 ◽  
pp. 1-18
Author(s):  
Jiaojiao Ren ◽  
Cong Wu
Keyword(s):  
Upper Bound ◽  
Probabilistic Models ◽  
Epistemic Uncertainty ◽  
Fuzzy Variable ◽  
Reliability Theory ◽  
Insufficient Data ◽  
Typical System ◽  
Binary State ◽  
Possibility Space ◽  
Parallel Series

This paper investigates Posbist reliability theory for typical systems with multicomponents. This theory is based on possibility and binary-state assumptions. It works well under situations of insufficient data and epistemic uncertainty. When the lifetime of every component of a typical system is assumed unrelated and a normal, strictly convex fuzzy variable in some possibility space, the Posbist reliability is concretely derived where the exactly value can be obtained at any moment, unlike existing ones only given by a lower and upper bound. We numerically compare the Posbist reliability between typical systems of four types: series, parallel, series-parallel, and parallel-series. Moreover, numerical safety evaluations are given based on possibilistic and probabilistic models.

Computing the Risk Indicators in Fuzzy Systems

2012 ◽  
Vol 5 (4) ◽  
pp. 63-84 ◽  
Author(s):  
Irina Georgescu
Keyword(s):  
Risk Aversion ◽  
Risk Premium ◽  
Stochastic Dominance ◽  
Probabilistic Models ◽  
Fuzzy Variable ◽  
Risk Indicators ◽  
Credibility Theory ◽  
Fuzzy Variables ◽  
Risk Situation ◽  
Definition Of

The modeling of complex risk situations imposes the existence of multiple ways to represent the risk and compare the risk situations between them. In probabilistic models, risk is described by random variables and risk situations are compared by stochastic dominance. In possibilistic or credibilistic models, risk is represented by fuzzy variables. This paper concerns three indicators of dominance associated with fuzzy variables. This allows the definition of three notions of fuzzy dominance: dominance in possibility, dominance in necessity and dominance in credibility. These three types of dominance are possibilistic and credibilistic versions of stochastic dominance. Each type offers a modality of ranking risk situations modeled by fuzzy variables. In the paper some properties of the three indicators of dominance are proved and relations between the three types of fuzzy dominance are established. For triangular fuzzy numbers formulas for the computation of these indicators are obtained. The paper also contains a contribution on a theory of risk aversion in the context of credibility theory. Using the credibilistic expected utility a notion of risk premium is defined as a measure of risk aversion of an agent in front of a risk situation described by a fuzzy variable and an approximate calculation formula of this indicator is proved.

Risk Study on Subway Construction Based on Reliability Theory

2010 ◽  
Vol 44-47 ◽  
pp. 1872-1877
Author(s):  
Ping Zhao ◽  
Feng Tian Hao
Keyword(s):  
Control System ◽  
System Reliability ◽  
Risk Control ◽  
Construction Safety ◽  
Reliability Theory ◽  
Distribution Theory ◽  
Allocation Method ◽  
Subway Construction ◽  
Parallel Series

This paper described the present risks existing in subway construction and proposed the idea that reliability theory can be applied in the field of subway construction. Based on this, a parallel-series model of risk control system was established. According to the required target of system reliability, combining with the reliability distribution theory, the reliabilities of each subsystem that constituted the parallel-series model can be determined. Aiming at the basic events that constituted the subsystem, average allocation method was taken to solve the basic events reliabilities and an example was given. This studies showed that reliability theory can be successfully applied in the field of subway construction and can fulfill the optimization of construction safety under a given security target.

ANALYSIS AND ALGORITHMS OF BIFUZZY SYSTEMS

2004 ◽  
Vol 12 (03) ◽  
pp. 357-376 ◽  
Author(s):  
JIAN ZHOU ◽  
BAODING LIU
Keyword(s):  
Numerical Experiments ◽  
Fuzzy Variable ◽  
Expected Value ◽  
Real Numbers ◽  
Fuzzy Variables ◽  
Chance Distribution ◽  
Expected Value Operator ◽  
Possibility Space ◽  
Bifuzzy Variable

A fuzzy variable is a function from a possibility space to the set of real numbers, while a bifuzzy variable is a function from a possibility space to the set of fuzzy variables. In this paper, a concept of chance distribution is originally presented for bifuzzy variable, and the linearity of expected value operator of bifuzzy variable is proved. Furthermore, bifuzzy simulations are designed and illustrated by some numerical experiments.

scholarly journals Gender fluidity as affordance negotiation

2020 ◽  
Author(s):  
Mahault Albarracin ◽  
Pierre Poirier
Keyword(s):  
Prediction Error ◽  
Probabilistic Models ◽  
Predictive Processing ◽  
Gender Fluidity ◽  
Social Scripts ◽  
Sensorimotor Interaction ◽  
Binary State ◽  
Gender Scripts ◽  
Cultural Niche ◽  
The Brain

Gender is often viewed as static binary state for people to embody, based on the sex they were assigned at birth. However, cultural studies increasingly understand gender as neither binary nor static, a view supported both in psychology and sociology. On this view, gender is negotiated between individuals, and highly dependent on context. Specifically, individuals are thought to be offered culturally gendered social scripts that allow them and their interlocutors the ability to predict future actions, and to understand the scene being set, establishing roles and expectations. We propose to understand scripts in the framework of enactive-ecological predictivism, which integrates aspects of ecological enactivism, notably the importance of dynamical sensorimotor interaction with an environment conceived as a field of affordances, and predictive processing, which views the brain as a predictive engine that builds its probabilistic models in an effort to reduce prediction error. Under this view, script-based negotiation can be linked to the enactive neuroscience concept of a cultural niche, as a landscape of cultural affordances. Affordances are possibilities for action that constrain what actions are pre-reflectively felt possible based on biological, experiential and cultural multisensorial cues. With the shifting landscapes of cultural affordances brought about by a number of recent social, technological and epistemic developments, the gender scripts offered to individuals are less culturally rigid, which translates in an increase in the variety of affordance fields each individual can negotiate. This entails that any individual has an increased possibility for gender fluidity, as shown by the increasing number of people currently identifying outside the binary.

Decision-Based Approach for Reliability Design

2006 ◽  
Vol 129 (5) ◽  
pp. 466-475 ◽  
Author(s):  
Efstratios Nikolaidis
Keyword(s):  
Probabilistic Models ◽  
Epistemic Uncertainty ◽  
Reliability Based Design Optimization ◽  
Insufficient Information ◽  
Design Problems ◽  
Reliability Design ◽  
Reliability Based Design ◽  
Trade Offs ◽  
New Formulation ◽  
Robust Reliability

We propose a decision-based approach for reliability design when there is insufficient information for constructing probabilistic models. The approach enables a designer to perform reliability-cost trade-offs and to assess the importance of variability and epistemic uncertainty. A method for decision under epistemic uncertainty is first presented and justified by presenting axioms on a decision maker’s (DM’s) preferences and by assuming that the DM’s goal is to find the most immune act (in terms of having undesirable consequences) to deviations of the state of the world from an expected state. Thus, the philosophy of the method is similar to that of robust reliability (Ben Haim, Y., 1996, Robust Reliability in the Mechanical Sciences, Springer-Verlag, Berlin). A new formulation of reliability design problems is proposed based on the above decision method and is compared to two reliability-based design optimization formulations that minimize cost given a maximum acceptable failure probability or maximize expected utility. The method is demonstrated on a decision where a designer has to choose between two materials for a structure.

Expected Value Operator of Random Fuzzy Variable and Random Fuzzy Expected Value Models

2003 ◽  
Vol 11 (02) ◽  
pp. 195-215 ◽  
Author(s):  
Yian-Kui Liu ◽  
Baoding Liu
Keyword(s):  
Fuzzy Variable ◽  
Expected Value ◽  
Fuzzy Simulation ◽  
Hybrid Intelligent Algorithm ◽  
Random Fuzzy Variable ◽  
Decision Systems ◽  
Expected Value Operator ◽  
Fuzzy Expected Value ◽  
Possibility Space ◽  
Definition Of

Random fuzzy variable is mapping from a possibility space to a collection of random variables. This paper first presents a new definition of the expected value operator of a random fuzzy variable, and proves the linearity of the operator. Then, a random fuzzy simulation approach, which combines fuzzy simulation and random simulation, is designed to estimate the expected value of a random fuzzy variable. Based on the new expected value operator, three types of random fuzzy expected value models are presented to model decision systems where fuzziness and randomness appear simultaneously. In addition, random fuzzy simulation, neural networks and genetic algorithm are integrated to produce a hybrid intelligent algorithm for solving those random fuzzy expected valued models. Finally, three numerical examples are provided to illustrate the feasibility and the effectiveness of the proposed algorithm.

Truncated Models for Probabilistic Weighted Retrieval

2022 ◽  
Vol 40 (3) ◽  
pp. 1-24
Author(s):  
Jiaul H. Paik ◽  
Yash Agrawal ◽  
Sahil Rishi ◽  
Vaishal Shah
Keyword(s):  
Performance Improvement ◽  
Upper Bound ◽  
Probabilistic Models ◽  
Modeling Error ◽  
Large Magnitude ◽  
Retrieval Models ◽  
Document Collections ◽  
Probabilistic Retrieval ◽  
Two Factors ◽  
Significant Performance

Existing probabilistic retrieval models do not restrict the domain of the random variables that they deal with. In this article, we show that the upper bound of the normalized term frequency ( tf ) from the relevant documents is much smaller than the upper bound of the normalized tf from the whole collection. As a result, the existing models suffer from two major problems: (i) the domain mismatch causes data modeling error, (ii) since the outliers have very large magnitude and the retrieval models follow tf hypothesis, the combination of these two factors tends to overestimate the relevance score. In an attempt to address these problems, we propose novel weighted probabilistic models based on truncated distributions. We evaluate our models on a set of large document collections. Significant performance improvement over six existing probabilistic models is demonstrated.

Generalisation of Dedekind's problem of the enumeration of coherent structures

1981 ◽  
Vol 89 (3-4) ◽  
pp. 239-248 ◽  
Author(s):  
J. Ansell ◽  
A. Bendell ◽  
S. Humble
Keyword(s):  
Coherent Structures ◽  
Upper Bound ◽  
Reliability Theory ◽  
Systematic Improvement ◽  
Enumeration Problem ◽  
Better Than

SynopsisIn the context of reliability theory, two definitions are given for coherent functions of n variables, where both function and variables can take any of l possible levels. The enumeration problem for such functions is discussed and several recursive bounds are derived. In the case of l = 2 (the Dedekind problem) a recursive upper bound is derived which is better than the previous best explicit upper bound forn < 15, and also provides a systematic improvement on this bound for larger values of n.

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