| 1. |
- Ahmadi, Alireza, et al.
(author)
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Risk of operational consequences of aircraft system failure
- 2010
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In: International Journal of Performability Engineering. - 0973-1318. ; 6:2, s. 149-158
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Journal article (peer-reviewed)abstract
- The purpose of this paper is to describe a methodology for identifying different operational consequences and associated costs caused by aircraft system failure, in order to facilitate and enhance the capability of taking correct and efficient decisions when analyzing the cost-effectiveness of maintenance tasks. The paper focuses on the operational consequences of failures that lead to delay. To identify the operational consequences of aircraft system failures, Empirical studies of possible scenarios involving aircraft failures and their operational consequences for a commercial airline have been performed. Empirical data were extracted through document studies and interviews, guided by the application of an Event Tree Analysis (ETA). In order to effectively utilize the knowledge of field experts in the assessment process, a pairwise comparison technique was adopted for quantifying the contribution of different factors to the operational. The work was performed together with experienced practitioners from both an aircraft manufacturer and commercial airlines, which contributed to a continuous verification of the outcome of the study.The study shows that the proposed methodology based on ETA and pairwise comparison can be used to identify and quantify the cost of operational consequences of failures in aircraft operation, when there is no sufficient and reliable data.
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| 2. |
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| 3. |
- Block, Jan, et al.
(author)
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Fleet-Level Reliability Analysis of Repairable Units: A Non-Parametric Approach using the Mean Cumulative Function
- 2013
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In: International Journal of Performability Engineering. - 0973-1318. ; 9:3, s. 333-344
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Journal article (peer-reviewed)abstract
- Complex technical systems are normally repaired rather than replaced when they fail. It is often desirable to analyze the reliability characteristics of these systems based on data generated in a customer use environment, in order to assess the reliability, frequency of failure or other parameters which may be influenced by the systems’ age and usage. Despite the advantages of continuously analyzing reliability data to be able to improve the maintenance programme continuously, methods such as parametric and non-parametric analysis are often ignored due to a belief that the mean time between failures (MTBF) is sufficient to describe the reliability pattern of repairable units. This paper describes the use of the mean cumulative function (MCF) and linear estimates based on the recurrence rate to predict the expected number of failures in the future. Reliability data from two repairable units are used to verify the procedure and comparison. The empirical data used in the paper is based on field data gathered during the operational life of the Swedish military aircraft system FPL 37 Viggen from 1977 to 2006, which essentially is the whole life cycle of the system.
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| 4. |
- Block, Jan, et al.
(author)
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Fleet-level Reliability of Multiple Repairable Units: a Parametric Approach using the Power Law Process
- 2014
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In: International Journal of Performability Engineering. - 0973-1318. ; 10:3, s. 239-250
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Journal article (peer-reviewed)abstract
- The application of parametric reliability analysis methods for repairable units, such as Power law process, is quite clear and straightforward for a single repairable unit. However, in practice, the analyst needs to know the reliability characteristics of units at a fleet level. The application of parametric reliability analysis methods at the fleet level, even if it is limited in scope, is quite complex. The aim of this paper is to describe the use of the power law process for multiple repairable units with differing reliability characteristics, to predict the expected number of failures at fleet level. The empirical data used in the paper are based on field data gathered during the operational life of two types of multi repairable units used in the Swedish military aircraft system FPL 37 Viggen from 1977 to 2006. The paper performs the trend test using TTT-based MIL-HDBK-189 and Laplace tests, and assesses the equality of shape-parameters for the intensity function of the power law process for multiple units. Estimation of the scale- and shape-parameters using maximum likelihood estimation is also performed. The parametric approach using power law process was found to yield relatively accurate estimations of number of failures, compared to empirical data
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| 5. |
- Candell, Olov, et al.
(author)
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Development of information system for e-maintenance solutions within the aerospace industry
- 2011
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In: International Journal of Performability Engineering. - 0973-1318. ; 7:6, s. 583-592
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Journal article (peer-reviewed)abstract
- Maintenance and support providers to modern aircraft need to manage an increasing amount of information generated by growing system complexity and stakeholder requirements. This introduces new risks in the information management process and makes traditional information services and systems inadequate. However, recent advancements in information and communication technology (ICT) have contributed to the emerging approach of e-Maintenance, which forms an important building block to achieve the desired information logistics. e-Maintenance enables remote and real time maintenance, and includes; collection, monitoring, analysis and distribution of data and information as decision-support to stakeholders of the maintenance and support processes, independent of organization or geographical location, 24 hours a day and 7 days a week (24/7). This paper describes a proposed development of information products by linking theories to practical methodologies and tools (e.g., Quality Function Deployment, QFD) through the development of a demonstrator of a stakeholder-based information product in the context of a modern combat aircraft. Read more about November 2011 P8 - Development of Information System for e-Maintenance Solutions within the Aerospace Industry by www.ijpe-online.com
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| 6. |
- Eker, O.F., et al.
(author)
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SVM based diagnostics on railway turnouts
- 2012
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In: International Journal of Performability Engineering. - 0973-1318. ; 8:3, s. 289-298
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Journal article (peer-reviewed)abstract
- Railway turnout systems are one of the most critical pieces of equipment in railway infrastructure. Early identification of failures in turnout systems is important to obtain increased availability and safety, and reduced operating and support costs. This paper aims to develop a method to identify 'drive-rod out-of-adjustment' failure mode, one of the most frequently observed failure modes. Support Vector Machine (SVM) with Gaussian kernel is used for diagnosis. In addition, the results of feature selection with statistical t-test and feature reduction with principal component analysis (PCA) are compared in the paper
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| 7. |
- Flammini, Francesco, Senior Lecturer, 1978-
(author)
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Model-based analysis of 'k out of m' correlation techniques for diverse redundant detectors
- 2013
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In: International Journal of Performability Engineering. - : RAMS Consultants. - 0973-1318. ; 9:5, s. 551-560
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Journal article (peer-reviewed)abstract
- Sensors are widespread in applications ranging from environmental monitoring to distributed surveillance for physical security. Novel protocols and appropriate topologies enable large networks of cheap smart-sensors with the main objective of providing pervasiveness and resilience. In this paper we provide a model-based analysis of a 'k-out-of-m' ('KooM') voting approach which can be used to correlate data coming from heterogeneous event detecting devices. The approach is based on the assumption of diverse redundancy on sensor technologies. The Bayesian Network formalism is employed to perform the analysis. The results show that by choosing appropriate correlation logics an optimal trade-off can be achieved among probability of detection, false alarm rate, availability and robustness against spoofing attempts, depending on the specific application. Furthermore, it will be shown that majority voting on detector outputs allows for a high cost effectiveness in obtaining performance improvements. © RAMS Consultants.
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| 8. |
- Fuqing, Yuan, et al.
(author)
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A comparative study of artificial neural networks and support vector machine for fault diagnosis
- 2013
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In: International Journal of Performability Engineering. - 0973-1318. ; 9:1, s. 49-60
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Journal article (peer-reviewed)abstract
- Fault detection is a crucial step in condition based maintenance requiring. The importance of fault diagnosis necessitates an efficient and effective failure pattern identification method. Artificial Neural Networks (ANN) and Support Vector Machines (SVM) emerging as prospective pattern recognition techniques in fault diagnosis have been showing its adaptability, flexibility and efficiency. Regardless of variants of the two techniques, this paper discusses the principle of the two techniques, and discusses their theoretical similarity and difference. Eventually using the commonest ANN, SVM, a case study is presented for fault diagnosis using a wide used bearing data. Their performances are compared in terms of accuracy, computational cost and stability
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| 9. |
- Fuqing, Yuan, et al.
(author)
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A cost model for repairable system considering multi-failure type over finite time horizon
- 2011
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In: International Journal of Performability Engineering. - 0973-1318. ; 7:2, s. 186-194
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Journal article (peer-reviewed)abstract
- In general, downtime of a system can be attributed due to multiple failure categories and repair costs for each failure categories can be different. Many of these failure types are repaired to a state which can be called as bad as old and such repair actions are termed as “minimal repair”. Many system or components are replaced after a certain number of such minimal repair actions. In this study, we intend to prove that if the system failure process can be described by NHPP (Non Homogenous Poisson Process), then each failure category can also be modelled by NHPP. Based on this, a cost model is developed by using the decomposition of the NHPP and renewal theory. Using the cost model, a model is developed to obtain the optimal number of minimum repair action every failure category. Since it is not possible to find any analytical solution, solution to the renewal function, an approximate approach is introduced to obtain numerical solution. Finally, a numerical example is presented to demonstrate the method.
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| 10. |
- Fuqing, Yuan, et al.
(author)
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Complex system reliability evaluation using support vector machine for incomplete data-set
- 2011
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In: International Journal of Performability Engineering. - 0973-1318. ; 7:1, s. 32-42
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Journal article (peer-reviewed)abstract
- Support Vector Machine (SVM) is an artificial intelligence technique that has been successfully used in data classification problems, taking advantage of its learning capacity. In systems modelled as networks, SVM has been used to classify the state of a network as failed or operating to approximate the network reliability. Due to the lack of information, or high computational complexity, the complete analytical expression of system states may be impossible to obtain, that is to say, only incomplete data-set can be obtained. Using these incomplete data-sets, depending on amount of missed data-set, this paper proposes two different approaches named rough approximation method and simulation based method to evaluate system reliability. SVM is used to make the incomplete data-set complete. Simulation technique is also employed in the so called simulation based approximation method. Several examples are presented to illustrate the approaches.
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| 11. |
- Fuqing, Yuan, et al.
(author)
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Proportional Intensity Model considering imperfect repair for repairable systems
- 2013
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In: International Journal of Performability Engineering. - 0973-1318. ; 9:2, s. 163-174
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Journal article (peer-reviewed)abstract
- The Proportional Intensity Model (PIM) extends the classical Proportional Hazard Model (PHM) in order to deal with repairable systems. This paper develops a more general PIM model which uses the imperfect model as baseline function. By using the imperfect model, the effectiveness of repair has been taken into account, without assuming an "as-bad-as-old" or an "as-good-as-new" scheme. Moreover, the effectiveness of other factors, such as the environmental conditions and the repair history, is considered as covariant in this PIM. In order to solve the large number parameters estimation problem, a Bayesian inference method is proposed. The Markov Chain Monte Carlo (MCMC) method is used to compute the posterior distribution for the Bayesian method. The Bayesian Information Criterion (BIC) is employed to perform model selection, namely, selecting the baseline function and remove the nuisance factors in this paper. In the final, a numerical example is provided to demonstrate the proposed model and method.
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| 12. |
- Fuqing, Yuan, et al.
(author)
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Statistical index development from time domain for rolling element bearings
- 2014
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In: International Journal of Performability Engineering. - 0973-1318. ; 10:3, s. 313-324
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Journal article (peer-reviewed)abstract
- Feature extraction is crucial to efficiently diagnose fault. This paper discusses a number of time-domain statistical features, including Kurtosis or the Crest Factor, the Mean by Deviation Ratio (MDR), and Symbolized Sequence Shannon Entropy (SSSE). The SSSE reflects the spatial distribution of the signal which is complementary with the statistical features. A new feature, Normalized Normal Negative Likelihood (NNNL), is used to improve the Normal Negative Likelihood (NNL). A Separation Index (SI) called the Extended SI (ESI) evaluates the performance of each feature and to remove noise feature. The Multi-Class Support Vector Machine (MSVM) recognizes bearing defect patterns. A numerical case is presented to demonstrate these features, their feature subset selection method and the pattern recognition method. The MSVM is used to detect three different types of bearing defects: defects in the inner race, outer race and bearing ball
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| 13. |
- Haftor, Darek, et al.
(author)
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Information Logistics as a Guide for
Research and Practice of e-Maintenance Operations
- 2011
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In: International Journal of Performability Engineering. - 0973-1318. ; 7:6, s. 593-603
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Journal article (peer-reviewed)abstract
- Although the development of e-maintenance operations is understood to offer promising opportunities, it seems to be mainly driven by Information and Communication Technologies (ICT) applications development. This is unfortunate, as ICT has no value in itself; rather its benefit comes from the way in which it is utilized within its particular context. Thus, a conceptual framework is proposed to guide both the practice and the research of e-maintenance operations. The framework combines an Industrial Value Chain with a Buyer- Consumer Value Chain, where their intersections articulated in terms of categories derived from Information Logistics. This provides a structure for the conception of e-maintenance that needs to be populated with published research and current e-maintenance practice. This may uncover white spaces where research efforts deserve particular attention and are driven by value generation – for instance, economic. A brief case study, from a leading European truck- manufacturer, illustrates the proposed conceptual framework in application.
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| 14. |
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| 15. |
- Hoseinie, Hadi, et al.
(author)
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Monte Carlo reliability simulation of coal shearer machine
- 2013
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In: International Journal of Performability Engineering. - 0973-1318. ; 9:5, s. 487-494
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Journal article (peer-reviewed)abstract
- In this paper the Kamat-Riley (K-R) event-based Monte Carlo simulation method was used for reliability analysis of longwall shearer machine. Shearer machine consists of six subsystems; water, haulage, electrical, hydraulic, cutting arms and cable systems in a series network configuration. A shearer in the Tabas coal mine was selected as case study and its all failure data were collected and used for reliability analysis of subsystems. With negligible assumption of time to repair, a flowchart was built for programming the simulation process. The Matlab mathematical programming software was used for reliability simulation process. Finally the reliability plot of longwall shearer machine was achieved and upper and lower bound reliability were calculated. The results illustrate that the reliability of shearer machine reduces to zero in a period of 100h. There is a 50% chance that the shearer will not fail for the first 12h of operation.
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| 16. |
- Kajko-Mattsson, Mira, et al.
(author)
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Essential components of e-maintenance
- 2011
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In: International Journal of Performability Engineering. - 0973-1318. ; 7:6, s. 555-571
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Journal article (peer-reviewed)abstract
- Many intellectual, societal, business and technological forces are continuously pushing forward the frontiers of science. When combined, they provide an umbrella for generating new fields and exploring new grounds. One such a new field is e-Maintenance. e-Maintenance addresses new needs and provides various benefits in form of increased availability, reduced lifecycle cost and increased customer value. However, it suffers from lack of a commonly defined basis supporting the existence of e-Maintenance and determining the essential components inherent in the e-Maintenance domain. In this paper, we suggest an initial set of components that serve as the groundwork of the e-Maintenance universe. The set outlines ten initial components. These are definition, business,organization, product,service,methodology,technology,information,customer,and education and training. The paper also suggests a definition of e-Maintenance, places eMaintenance in the context of other e-Domains, and elicits e-Maintenance intellectual opportunities and challenges to be met by both the academia and industry.
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| 17. |
- Kumar, Rupesh, et al.
(author)
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Improving maintainability in extreme cold climatic conditions
- 2012
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In: International Journal of Performability Engineering. - 0973-1318. ; 8:5, s. 563-572
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Journal article (peer-reviewed)abstract
- The maintainability issue is critical for the successful and effective operation of any industry in the extreme cold climatic conditions as the working conditions are made very difficult by low temperature, ice, short period of daylight and lack of support facilities. The objective of this paper is to identify potential risk factors in cold conditions and to provide ergonomic guidelines to reduce risk factors and increase maintainability of industries deployed in cold climate
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| 18. |
- Kumar, Uday, et al.
(author)
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Current trends in maintenance engineering
- 2011
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In: International Journal of Performability Engineering. - : RAMS Consultants. - 0973-1318. ; 7:6, s. 503-504
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Journal article (other academic/artistic)
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| 19. |
- Lin, Jing, et al.
(author)
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Bayesian survival analysis in reliability for complex system with a cure fraction
- 2011
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In: International Journal of Performability Engineering. - 0973-1318. ; 7:2, s. 109-120
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Journal article (peer-reviewed)abstract
- In traditional methods for reliability analysis, one complex system is often considered as being composed by some subsystems in series. Usually, the failure of any subsystem would be supposed to lead to the failure of the entire system. However, some subsystems' lifetimes are long enough and even never fail during the life cycle of the entire system. Moreover, such subsystems' lifetimes will not be influenced equally under different circumstances. In practice, such interferences will affect the model's accuracy, but it is seldom considered in traditional analysis. To address these shortcomings, this paper presents a new approach to do reliability analysis for complex systems. Here a certain fraction of the subsystems is defined as a "cure fraction" under the consideration that such subsystems' lifetimes are long enough and even never fail during the life cycle of the entire system. By introducing environmental covariates and the joint power prior, the proposed model is developed within the Bayesian survival analysis framework, and thus the problem for censored (or truncated) data in reliability tests can be resolved. In addition, a Markov chain Monte Carlo computational scheme is implemented and a numeric example is discussed to demonstrate the proposed model
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| 20. |
- Patra, Ambika Prasad, et al.
(author)
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Cost Effective Maintenance Policy: A Case Study
- 2010
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In: International Journal of Performability Engineering. - India : RAMS Consultants. - 0973-1318. ; 6:6, s. 595-603
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Journal article (peer-reviewed)abstract
- The European Rail Traffic Management System (ERTMS) is a major venture initiated by the European Union in order to create an interoperable railway network within Europe. The manufacturers of the ERTMS strive to attain a competitive edge by demonstrating the efficiency of their systems. Achieving the optimal cost effectiveness is one of the significant ways to address the efficiency of the system and involves maximising the availability and minimising the life cycle cost of the system over the system life cycle. One of the important ways of maximising the cost effectiveness of the system is to optimise the maintenance policy. This paper demonstrates the estimation of the cost effectiveness of an ERTMS system. The degradation and repair process of the system is modelled by Petri-Nets. Failure, maintenance and cost data are used as parameters for the model. The model will be useful for systems that experience degradations and are subjected to imperfect maintenance.
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| 21. |
- Söderholm, Peter, et al.
(author)
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Design of experiment and simulation for identification of significant e-maintenance services
- 2011
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In: International Journal of Performability Engineering. - 0973-1318. ; 7:1, s. 77-90
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Journal article (peer-reviewed)abstract
- The purpose of this paper is to present a methodology and a supporting toolbox that identify information-based maintenance support services using an evaluation of the services' impacts on the effectiveness of complex technical systems. A hypothetical aircraft and its support system are simulated in SIMLOX. The variables included in the model, as well as their expected effects on critical measures of system-effectiveness, were identified through interviews and studies of documents and the literature. The simulations have been planned and analysed according to established Design of Experiment (DoE) principles supported by MATLAB. Microsoft Access and Microsoft Visual Studio.NET has been used to integrate SIMLOX and MATLAB. The outcome of the study was scrutinised by both practitioners and statisticians. The methodology and its toolbox are useful for those involved in simulation work or the development of information services that support maintenance activities. The proposed systematic methodology, along with its supporting toolbox, identifies information-based services that are currently lacking when applying a Service-Oriented Architecture (SOA) approach during design and are considered valuable in identifying information-based maintenance support services within an eMaintenance solution
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