| 1. |
- Bergman, Bo, et al.
(författare)
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Letter to the editors
- 1988
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Ingår i: Reliability Engineering & System Safety. - : Elsevier BV. - 0951-8320 .- 1879-0836. ; 21:2, s. 155-160
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 2. |
- Hollnagel, Erik
(författare)
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Looking for errors of omission and commission or The Hunting of the Snark revisited
- 2000
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Ingår i: Reliability Engineering & System Safety. - 0951-8320 .- 1879-0836. ; 68:2, s. 135-145
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Tidskriftsartikel (refereegranskat)abstract
- Since the early 1990s, considerable effort has been spent to understand what is meant by an `error of commission' (EOC), to complement the traditional notion of an `error of omission' (EOO). This paper argues that the EOO-EOC dyad, as an artefact of the PSA event tree, is insufficient for human reliability analysis (HRA) for several reasons: (1) EOO-EOC fail to distinguish between manifestation and cause, (2) EOO-EOC refer to classes of incorrect actions rather than to specific instances: (3) there is no unique way of classifying an event using EOO-EOC, (4) the set of error modes that cannot reasonably be classified as EOO is too diverse to fit into any single category of its own. Since the use of EOO-EOC leads to serious problems for HRA. an alternative is required. This can be found in the concept of error modes, which has a long history in risk analysis. A specific system for error mode prediction was tested in a simulator experiment. The analysis of the results showed that error modes could be qualitatively predicted with sufficient accuracy (68% correct) to propose this method as a way to determine how operator actions can fail in PSA-cum-HRA. Although this still leaves the thorny issue of quantification, a consistent prediction of error modes provides a better starting point for determining probabilities than the EOO-EOC dyad. It also opens a possibility for quantification methods where the influence of the common performance conditions is prior to and more important than individual failure rates.
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| 3. |
- Kumar, Dhananjay, et al.
(författare)
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Proportional hazards model : a review
- 1994
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Ingår i: Reliability Engineering & System Safety. - : Elsevier BV. - 0951-8320 .- 1879-0836. ; 44:2, s. 177-188
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Tidskriftsartikel (refereegranskat)abstract
- The proportional hazards model was introduced in 1972 by D. R. Cox in order to estimate the effects of different covariates influencing the times to the failures of a system. The model has been used rather extensively in biomedicine and, recently, interest in its application in reliability engineering has increased. The main purpose of this expository paper is to review the existing literature on the proportional hazards model. At first, the characteristics of the method are explained and its importance in reliability analysis is presented. Subsequently, methods for estimating parameters, along with the small and large sample properties of the estimators, are briefly discussed. Afterwards, work carried out so far on topics such as the effects of interaction, omission, measurement error, misclassification, monotonicity, multicolinearity and time dependency of covariates on the estimator are summarized. Some goodness-of-fit tests, especially those based on graphical methods, are described. We also describe some possible extensions of this model considered so far and available computer programs and packages for estimating the parameters of this model. Finally, some areas for further research are also discussed. (100 refs.)
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| 4. |
- Kumar, Dhananjay, et al.
(författare)
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Reliability analysis of power transmission cables of electric mine loaders using the proportional hazards model
- 1992
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Ingår i: Reliability Engineering & System Safety. - : Elsevier BV. - 0951-8320 .- 1879-0836. ; 37:3, s. 217-222
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Tidskriftsartikel (refereegranskat)abstract
- The proportional hazards model (PHM) is a powerful technique which can be used to investigate the effects of operating environment and the diagnostic variables (covariates) associated with an item on its life length. The effects of two different designs and maintenance on the reliability of a power transmission cable of an electric mine loader is investigated using PHM. The purpose is to illustrate the application of this model in making decisions about selecting the proper material or designing an item to meet the required purpose efficiently. (11 refs.)
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| 5. |
- Kumar, Uday, et al.
(författare)
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Reliability analysis of hydraulic systems of LHD machines using the power law process model
- 1992
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Ingår i: Reliability Engineering & System Safety. - : Elsevier BV. - 0951-8320 .- 1879-0836. ; 35:3, s. 217-224
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Tidskriftsartikel (refereegranskat)abstract
- Previously, a preliminary study of the reliability characteristics of a fleet of load-haul-dump (LHD) machines deployed at Kiruna mine showed that the engine and the hydraulics are the two most critical subsystems. Hydraulic systems are selected for further study because such systems are still under a development phase. Maintenance data for two years for these machines are analyzed. The tests for trends and serial correlation show that times between successive failures for the hydraulic systems are in most cases not independent and identically distributed. Goodness-of-fit tests show that the power law process model provides a good fit to the failure data of the hydraulic systems. Methods for parameter estimation in the power law process model and estimation of optimal maintenance intervals for such systems are presented. Emphasis is on the use of graphical methods for data analysis (14 refs.)
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| 6. |
- Kumar, Uday, et al.
(författare)
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Reliability investigation for a fleet of load haul dump machines in a Swedish mine
- 1989
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Ingår i: Reliability Engineering & System Safety. - : Elsevier BV. - 0951-8320 .- 1879-0836. ; 26:4, s. 341-361
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Tidskriftsartikel (refereegranskat)abstract
- The recent trends of deployment of complex and capital intensive equipment in mines has created interest in the field of maintenance and operational reliability of this equipment. The failure consequences associated with random equipment failures have considerable influence on the total operating cost of a highly mechanized mining system. Keeping this in view, a reliability investigation was initiated for a fleet of diesel operated load-haul-dump (LHD) machines in a Swedish mine. The goal is to estimate the operational reliability of these machines, locate items or assemblies which need improvement in design to enhance the reliability and to decide the duration of optimal preventive maintenance. Failure data for one year of LHD machines are analysed using the recently developed graphical technique of total time on test (TTT) plotting. Analytical methods like Kolmogorov-Smirnov test and maximum likelihood estimation are used in the analysis. The importance of testing the reliability data for the presence of trends and serial correlation is also emphasized.
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| 7. |
- Sjöberg, Lennart
(författare)
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Author's reply: Whose risk perception should influence decisions?
- 2001
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Ingår i: Reliability Engineering & System Safety. - : Elsevier Ltd. - 1879-0836 .- 0951-8320. ; 72:2, s. 149-151
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- My paper is being commented upon in three interesting papers [1], [2], [3]. I will deal with them in turn since they are quite different and will finish with a discussion of a common theme.
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| 8. |
- Sjöberg, Lennart
(författare)
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Political decisions and public risk perception
- 2001
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Ingår i: Reliability Engineering & System Safety. - : Elsevier Ltd. - 1879-0836 .- 0951-8320. ; 72:2, s. 115-123
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Tidskriftsartikel (refereegranskat)abstract
- Should the public's risk perception be an input into political and administrative decision making? It is clear that it does have an influence, but perhaps not to the extent of explaining all, or even most, of the tremendous inconsistencies in the allocation of resources for risk mitigation. Risk perception models could be of help to understand such phenomena, but contemporary models of risk perception have been misleading and their weaknesses are discussed. Similarly, experts' risk perception has been asserted to be very different from that of the public but that is argued here to be a mistaken opinion. Should we let the experts run risk policy? Several arguments against this idea are put forward here, the most important being that the whole issue is one of democracy. Those who are unhappy about the decisions made by the government can always argue their case and maybe gain political power to change things. This is as true of risk policy as it is of everything else.
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| 9. |
- Allahvirdizadeh, Reza, et al.
(författare)
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Improved dynamic design method of ballasted high-speed railway bridges using surrogate-assisted reliability-based design optimization of dependent variables
- 2023
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Ingår i: Reliability Engineering & System Safety. - : Elsevier BV. - 0951-8320 .- 1879-0836. ; 238
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Tidskriftsartikel (refereegranskat)abstract
- Operating high-speed trains imposes excessive vibrations to bridges raising concerns about their safety. In this context, it was shown that some conventional design methods such as those related to the running safety suffer from a vague scientific background questioning their reliability or optimality. Therefore, the current article is devoted to updating the conventional design methodology, using Reliability-Based Design Optimization (RBDO) to propose the minimum allowable mass and stiffness which assures satisfying the target reliability. These proposed minimum design values can conceptually replace the conventional partial safety factor-based design method for running safety without the need for dynamic analysis. If the mass and stiffness resulting from the control of other limit states meet the proposed minimum values, the desired target reliability for running safety will be assured. This is achieved by adaptively training Kriging meta-models as a surrogate for the computational models decoupling the RBDO problem. In this regard, a new stopping criteria is proposed using mis-classification ratio of the cross-validated model; which reduces the generalization error of the trained meta-model and consequently the estimated failure probability. Moreover, due to the dependence of the design variables, the Copula concept is used to refine the augmented space and reformulate the RBDO problem.
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| 10. |
- Arias Chao, Manuel, et al.
(författare)
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Fusing physics-based and deep learning models for prognostics
- 2022
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Ingår i: Reliability Engineering & System Safety. - : Elsevier. - 0951-8320 .- 1879-0836. ; 217
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Tidskriftsartikel (refereegranskat)abstract
- Physics-based and data-driven models for remaining useful lifetime (RUL) prediction typically suffer from two major challenges that limit their applicability to complex real-world domains: (1) the incompleteness of physics-based models and (2) the limited representativeness of the training dataset for data-driven models. Combining the advantages of these two approaches while overcoming some of their limitations, we propose a novel hybrid framework for fusing the information from physics-based performance models with deep learning algorithms for prognostics of complex safety-critical systems. In the proposed framework, we use physics-based performance models to infer unobservable model parameters related to a system’s components health by solving a calibration problem. These parameters are subsequently combined with sensor readings and used as input to a deep neural network, thereby generating a data-driven prognostics model with physics-augmented features. The performance of the hybrid framework is evaluated on an extensive case study comprising run-to-failure degradation trajectories from a fleet of nine turbofan engines under real flight conditions. The experimental results show that the hybrid framework outperforms purely data-driven approaches by extending the prediction horizon by nearly 127%. Furthermore, it requires less training data and is less sensitive to the limited representativeness of the dataset as compared to purely data-driven approaches. Furthermore, we demonstrated the feasibility of the proposed framework on the original CMAPSS dataset, thereby confirming its superior performance.
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