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The probabilistic and possibilistic methods of reliability analysis of structures have been developed independently. However, the designers will prefer the flexibility of modeling the structural parameter uncertainty either probabilistically or possibilistically depending on the nature and quality of the available data. Thereby, the complex structural model will involve both types of uncertain parameters...
It is conducive to ensuring the safety and reliability of the power system that the timely and accurate evaluation of the reliability of the large generator. A composite evaluation method of the fault probability for the large generator based on the multi-characteristic parameters is proposed in this paper, and it can be employed to solve the difficult problem how the occurrence probability of fault...
In conventional fault tree analysis (FTA), some complex and uncertain events such as human errors cannot be handled effectively. Fuzzy fault tree analysis (fuzzy FTA) integrating fuzzy set evaluation and probabilistic estimation is proposed to evaluate vague events. The reliability of water supply subsystem in fire protection systems is analyzed using the proposed approach and the results prove the...
The uncertainty associated with load forecast is a challenging issue in reliability evaluation and transmission planning. The uncertainty cannot be always represented by a probability distribution. This paper presents a method to include a fuzzy load model in reliability evaluation of mixed AC-DC supply systems. The presented fuzzy load model and three-state probability model for HVDC poles can be...
According to the relationship between the natural frequency of a system and the excitation frequency, the resonance rule of fuzzy failure for the multi-freedom vibration system is built. The fuzzy resonance reliability of vibration system based on the importance sampling method has a more reasonable measurement of the probability of vibration system on resonant failure. The example on fuzzy resonance...
A technique using a fuzzy search method which is based on fuzzy multi-criteria function has been proposed for GMS(generator maintenance scheduling) in order to consider uncertainties of forced outage rate of generators and multi-objective function. This paper evaluates the results of maintenance scheduling of the seven generation company obtained by the previous proposed method. Especially this paper...
In this paper transmission power system structure optimization is performed via a minimal spanning tree based encoded fuzzy logic self-controlled hybrid genetic algorithm (GA). During the redundancy optimization of the power system network a binary encoded GA is used for a modified transmission network expansion problem, finding the optimal power line type with respect to the net present value (NPV)...
According to characteristics of bracing engineering for deep foundation pit in metro, an index system for supporting scheme is established. Using the theory of fuzzy probability and analytic hierarchy process (AHP), a comprehensive assessment model is constructed to optimize supporting scheme for deep excavation of metro. In order to assess the index weights scientifically, the fuzzy weighted value...
It shows probabilities of each basic event for burning and blasting of LPG tanks applying triangle fuzzy numerals. The distribution of probability for top event is calculated on the base of fault tree and fuzzy operators. Median method is applied to analyze fuzzy significance. Combined with sequence of each fuzzy significance, the major sequence of hidden danger and harmful factors for burning and...
This paper introduces a method to analyze the performance of a system through the rank correlation between the fuzzy probist reliability of its components. The fuzzy probist reliability of each component is obtained using restricted fuzzy algebra and linear programming technique. And the proposed method is illustrated by analyzing the performance of the Web page `Departments' of the Web site www.ssn...
Information Fusion is a valid way which can decrease the uncertainty of making decision, and is also a hotspot. The paper makes some work on a important problem about Fuzzy Integral, that is how to get the Fuzzy Density, and compares two typical means. Based on 11 UCI data set, this paper conducts the compared experiment of several Information Fusion methods. It is compared with references 4 and 5...
Fuzzy travel time reliability on road network is presented in the paper, which shows travelers' expected travel time and tolerance to delay by membership function. In virtue of the stochastic users' equilibrium model, the fuzzy travel time reliability is obtained under day-to-day variations in travel demand. A scenario-based analysis method is proposed to estimate the probability of a path travel...
Fuzzy reliability analysis is of great importance for structural engineering such as arch dams, large concrete dams etc. In this paper, an improved method of fuzzy reliability analysis on deep sliding surface in rock foundation under dam is established. Firstly, this paper discussed how to determine the probability density function of structure. Secondly, according to the knowledge of fuzzy mathematics...
Traditional fault tree analysis method need obtain exact value of the event occurrence's probability, un-completeness and fuzziness of the data is ignored. Fuzzy fault tree analysis method is proposed in study on the system reliability. The fuzzy fault tree of the AUV is established. Using operational rule calculated the fuzzy probability of the top event which is AUV can't work normally and analysis...
Dempster's combination rule is the most popular rule of combinations, but it is a poor solution for the management of the conflict between various information sources at the normalization step. Even when it faces high conflict information, the classical Dempster-Shafer theory can involve counter-intuitive results. To solve this problem, this paper combines fuzzy theory to put forward new improved...
A conceptual possibility-probability based framework is proposed to manage the uncertainties encountered in distribution system reliability. Probability distribution of reliability parameters, the failure rate, the load point outage duration and the power injection of feeder branch are transformed consistently into the corresponding possibilistic distribution function. Under the proposed framework,...
An evaluation based upon the freshness degree of agricultural products for reliability of logistics services is proposed. Considering freshness, the failure possibility of logistics services is not only of randomness, but also of fuzziness. Past studies are probability models based on determined criteria, disregarding the fuzziness of the failure of logistics services. In this paper, both the randomness...
The process industry has always been faced with the difficult task of determining the required integrity of safeguarding systems such as safety instrumented systems (SISs). The ANSI/ISA S84.01-1996 and IEC 61508 safety standards provide guidelines for the design, installation, operation, maintenance, and test of SIS. However, in the field, there is a considerable lack of understanding of how to apply...
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