HUMAN RELIABILITY ANALYSIS DENGAN PENDEKATAN COGNITIVE RELIABILITY AND ERROR ANALYSIS METHOD (CREAM

Directory of Open Access Journals (Sweden)

Zahirah Alifia Maulida

2015-01-01

Full Text Available Kecelakaan kerja pada bidang grinding dan welding menempati urutan tertinggi selama lima tahun terakhir di PT. X. Kecelakaan ini disebabkan oleh human error. Human error terjadi karena pengaruh lingkungan kerja fisik dan non fisik.Penelitian kali menggunakan skenario untuk memprediksi serta mengurangi kemungkinan terjadinya error pada manusia dengan pendekatan CREAM (Cognitive Reliability and Error Analysis Method. CREAM adalah salah satu metode human reliability analysis yang berfungsi untuk mendapatkan nilai Cognitive Failure Probability (CFP yang dapat dilakukan dengan dua cara yaitu basic method dan extended method. Pada basic method hanya akan didapatkan nilai failure probabailty secara umum, sedangkan untuk extended method akan didapatkan CFP untuk setiap task. Hasil penelitian menunjukkan faktor- faktor yang mempengaruhi timbulnya error pada pekerjaan grinding dan welding adalah kecukupan organisasi, kecukupan dari Man Machine Interface (MMI & dukungan operasional, ketersediaan prosedur/ perencanaan, serta kecukupan pelatihan dan pengalaman. Aspek kognitif pada pekerjaan grinding yang memiliki nilai error paling tinggi adalah planning dengan nilai CFP 0.3 dan pada pekerjaan welding yaitu aspek kognitif execution dengan nilai CFP 0.18. Sebagai upaya untuk mengurangi nilai error kognitif pada pekerjaan grinding dan welding rekomendasi yang diberikan adalah memberikan training secara rutin, work instrucstion yang lebih rinci dan memberikan sosialisasi alat. Kata kunci: CREAM (cognitive reliability and error analysis method, HRA (human reliability analysis, cognitive error Abstract The accidents in grinding and welding sectors were the highest cases over the last five years in PT. X and it caused by human error. Human error occurs due to the influence of working environment both physically and non-physically. This study will implement an approaching scenario called CREAM (Cognitive Reliability and Error Analysis Method. CREAM is one of human

RELIABILITY ANALYSIS OF BENDING ELIABILITY ANALYSIS OF ...

African Journals Online (AJOL)

eobe

Reliability analysis of the safety levels of the criteria slabs, have been .... was also noted [2] that if the risk level or β < 3.1), the ... reliability analysis. A study [6] has shown that all geometric variables, ..... Germany, 1988. 12. Hasofer, A. M and ...

Reliability analysis techniques in power plant design

International Nuclear Information System (INIS)

Chang, N.E.

1981-01-01

An overview of reliability analysis techniques is presented as applied to power plant design. The key terms, power plant performance, reliability, availability and maintainability are defined. Reliability modeling, methods of analysis and component reliability data are briefly reviewed. Application of reliability analysis techniques from a design engineering approach to improving power plant productivity is discussed. (author)

Reliability analysis of shutdown system

International Nuclear Information System (INIS)

Kumar, C. Senthil; John Arul, A.; Pal Singh, Om; Suryaprakasa Rao, K.

2005-01-01

This paper presents the results of reliability analysis of Shutdown System (SDS) of Indian Prototype Fast Breeder Reactor. Reliability analysis carried out using Fault Tree Analysis predicts a value of 3.5 x 10 -8 /de for failure of shutdown function in case of global faults and 4.4 x 10 -8 /de for local faults. Based on 20 de/y, the frequency of shutdown function failure is 0.7 x 10 -6 /ry, which meets the reliability target, set by the Indian Atomic Energy Regulatory Board. The reliability is limited by Common Cause Failure (CCF) of actuation part of SDS and to a lesser extent CCF of electronic components. The failure frequency of individual systems is -3 /ry, which also meets the safety criteria. Uncertainty analysis indicates a maximum error factor of 5 for the top event unavailability

Reliability engineering analysis of ATLAS data reprocessing campaigns

International Nuclear Information System (INIS)

Vaniachine, A; Golubkov, D; Karpenko, D

2014-01-01

During three years of LHC data taking, the ATLAS collaboration completed three petascale data reprocessing campaigns on the Grid, with up to 2 PB of data being reprocessed every year. In reprocessing on the Grid, failures can occur for a variety of reasons, while Grid heterogeneity makes failures hard to diagnose and repair quickly. As a result, Big Data processing on the Grid must tolerate a continuous stream of failures, errors and faults. While ATLAS fault-tolerance mechanisms improve the reliability of Big Data processing in the Grid, their benefits come at costs and result in delays making the performance prediction difficult. Reliability Engineering provides a framework for fundamental understanding of the Big Data processing on the Grid, which is not a desirable enhancement but a necessary requirement. In ATLAS, cost monitoring and performance prediction became critical for the success of the reprocessing campaigns conducted in preparation for the major physics conferences. In addition, our Reliability Engineering approach supported continuous improvements in data reprocessing throughput during LHC data taking. The throughput doubled in 2011 vs. 2010 reprocessing, then quadrupled in 2012 vs. 2011 reprocessing. We present the Reliability Engineering analysis of ATLAS data reprocessing campaigns providing the foundation needed to scale up the Big Data processing technologies beyond the petascale.

Integrating reliability analysis and design

International Nuclear Information System (INIS)

Rasmuson, D.M.

1980-10-01

This report describes the Interactive Reliability Analysis Project and demonstrates the advantages of using computer-aided design systems (CADS) in reliability analysis. Common cause failure problems require presentations of systems, analysis of fault trees, and evaluation of solutions to these. Results have to be communicated between the reliability analyst and the system designer. Using a computer-aided design system saves time and money in the analysis of design. Computer-aided design systems lend themselves to cable routing, valve and switch lists, pipe routing, and other component studies. At EG and G Idaho, Inc., the Applicon CADS is being applied to the study of water reactor safety systems

Multi-Disciplinary System Reliability Analysis

Science.gov (United States)

Mahadevan, Sankaran; Han, Song

1997-01-01

The objective of this study is to develop a new methodology for estimating the reliability of engineering systems that encompass multiple disciplines. The methodology is formulated in the context of the NESSUS probabilistic structural analysis code developed under the leadership of NASA Lewis Research Center. The NESSUS code has been successfully applied to the reliability estimation of a variety of structural engineering systems. This study examines whether the features of NESSUS could be used to investigate the reliability of systems in other disciplines such as heat transfer, fluid mechanics, electrical circuits etc., without considerable programming effort specific to each discipline. In this study, the mechanical equivalence between system behavior models in different disciplines are investigated to achieve this objective. A new methodology is presented for the analysis of heat transfer, fluid flow, and electrical circuit problems using the structural analysis routines within NESSUS, by utilizing the equivalence between the computational quantities in different disciplines. This technique is integrated with the fast probability integration and system reliability techniques within the NESSUS code, to successfully compute the system reliability of multi-disciplinary systems. Traditional as well as progressive failure analysis methods for system reliability estimation are demonstrated, through a numerical example of a heat exchanger system involving failure modes in structural, heat transfer and fluid flow disciplines.

Fundamentals and applications of systems reliability analysis

International Nuclear Information System (INIS)

Boesebeck, K.; Heuser, F.W.; Kotthoff, K.

1976-01-01

The lecture gives a survey on the application of methods of reliability analysis to assess the safety of nuclear power plants. Possible statements of reliability analysis in connection with specifications of the atomic licensing procedure are especially dealt with. Existing specifications of safety criteria are additionally discussed with the help of reliability analysis by the example of the reliability analysis of a reactor protection system. Beyond the limited application to single safety systems, the significance of reliability analysis for a closed risk concept is explained in the last part of the lecture. (orig./LH) [de

Reliability analysis of software based safety functions

International Nuclear Information System (INIS)

Pulkkinen, U.

1993-05-01

The methods applicable in the reliability analysis of software based safety functions are described in the report. Although the safety functions also include other components, the main emphasis in the report is on the reliability analysis of software. The check list type qualitative reliability analysis methods, such as failure mode and effects analysis (FMEA), are described, as well as the software fault tree analysis. The safety analysis based on the Petri nets is discussed. The most essential concepts and models of quantitative software reliability analysis are described. The most common software metrics and their combined use with software reliability models are discussed. The application of software reliability models in PSA is evaluated; it is observed that the recent software reliability models do not produce the estimates needed in PSA directly. As a result from the study some recommendations and conclusions are drawn. The need of formal methods in the analysis and development of software based systems, the applicability of qualitative reliability engineering methods in connection to PSA and the need to make more precise the requirements for software based systems and their analyses in the regulatory guides should be mentioned. (orig.). (46 refs., 13 figs., 1 tab.)

R&D program benefits estimation: DOE Office of Electricity Delivery and Energy Reliability

Energy Technology Data Exchange (ETDEWEB)

None, None

2006-12-04

The overall mission of the U.S. Department of Energy’s Office of Electricity Delivery and Energy Reliability (OE) is to lead national efforts to modernize the electric grid, enhance the security and reliability of the energy infrastructure, and facilitate recovery from disruptions to the energy supply. In support of this mission, OE conducts a portfolio of research and development (R&D) activities to advance technologies to enhance electric power delivery. Multiple benefits are anticipated to result from the deployment of these technologies, including higher quality and more reliable power, energy savings, and lower cost electricity. In addition, OE engages State and local government decision-makers and the private sector to address issues related to the reliability and security of the grid, including responding to national emergencies that affect energy delivery. The OE R&D activities are comprised of four R&D lines: High Temperature Superconductivity (HTS), Visualization and Controls (V&C), Energy Storage and Power Electronics (ES&PE), and Distributed Systems Integration (DSI).

Power system reliability analysis using fault trees

International Nuclear Information System (INIS)

Volkanovski, A.; Cepin, M.; Mavko, B.

2006-01-01

The power system reliability analysis method is developed from the aspect of reliable delivery of electrical energy to customers. The method is developed based on the fault tree analysis, which is widely applied in the Probabilistic Safety Assessment (PSA). The method is adapted for the power system reliability analysis. The method is developed in a way that only the basic reliability parameters of the analysed power system are necessary as an input for the calculation of reliability indices of the system. The modeling and analysis was performed on an example power system consisting of eight substations. The results include the level of reliability of current power system configuration, the combinations of component failures resulting in a failed power delivery to loads, and the importance factors for components and subsystems. (author)

To transfer or not to transfer? Evidence from validity and reliability tests for international transfers of non-market adaptation benefits in river basins.

Science.gov (United States)

Andreopoulos, Dimitrios; Damigos, Dimitrios

2017-01-01

The attempt to design cost-effective adaptation policies incorporating non-market values to inhibit climate change impacts on water resources may increase the interest in applying the Benefit Transfer method. Benefit Transfer is a practical way to consider non-market values using functions and estimates acquired through primary valuation methods from other sites. Among the primary methods, Choice Experiments appear to particularly accommodate Benefit Transfer. Nevertheless, validity and reliability of international value transfers obtained from Choice Experiments have not been adequately examined. To this end, two identical Choice Experiments were conducted in Greece and Italy in the context of river services adaptation, testing validity and reliability of Benefit Transfer. The application of validity and reliability tests for different types of transfers is supportive for the use of Benefit Transfer, at least for the value transfer types. In particular the reliability of value transfer was higher when income adjustments were taken into account. Overall, Benefit Transfer can be attentively considered to evaluate cost-effective adaptation policies across countries experiencing similar climate change trends. The latter gains more importance given that an international Benefit Transfer setting as regards the non-market benefits of adaptation to climate change for river services is absent in the relevant literature. Copyright © 2016 Elsevier Ltd. All rights reserved.

Reliability analysis under epistemic uncertainty

International Nuclear Information System (INIS)

Nannapaneni, Saideep; Mahadevan, Sankaran

2016-01-01

This paper proposes a probabilistic framework to include both aleatory and epistemic uncertainty within model-based reliability estimation of engineering systems for individual limit states. Epistemic uncertainty is considered due to both data and model sources. Sparse point and/or interval data regarding the input random variables leads to uncertainty regarding their distribution types, distribution parameters, and correlations; this statistical uncertainty is included in the reliability analysis through a combination of likelihood-based representation, Bayesian hypothesis testing, and Bayesian model averaging techniques. Model errors, which include numerical solution errors and model form errors, are quantified through Gaussian process models and included in the reliability analysis. The probability integral transform is used to develop an auxiliary variable approach that facilitates a single-level representation of both aleatory and epistemic uncertainty. This strategy results in an efficient single-loop implementation of Monte Carlo simulation (MCS) and FORM/SORM techniques for reliability estimation under both aleatory and epistemic uncertainty. Two engineering examples are used to demonstrate the proposed methodology. - Highlights: • Epistemic uncertainty due to data and model included in reliability analysis. • A novel FORM-based approach proposed to include aleatory and epistemic uncertainty. • A single-loop Monte Carlo approach proposed to include both types of uncertainties. • Two engineering examples used for illustration.

Reliability analysis techniques for the design engineer

International Nuclear Information System (INIS)

Corran, E.R.; Witt, H.H.

1982-01-01

This paper describes a fault tree analysis package that eliminates most of the housekeeping tasks involved in proceeding from the initial construction of a fault tree to the final stage of presenting a reliability analysis in a safety report. It is suitable for designers with relatively little training in reliability analysis and computer operation. Users can rapidly investigate the reliability implications of various options at the design stage and evolve a system which meets specified reliability objectives. Later independent review is thus unlikely to reveal major shortcomings necessitating modification and project delays. The package operates interactively, allowing the user to concentrate on the creative task of developing the system fault tree, which may be modified and displayed graphically. For preliminary analysis, system data can be derived automatically from a generic data bank. As the analysis proceeds, improved estimates of critical failure rates and test and maintenance schedules can be inserted. The technique is applied to the reliability analysis of the recently upgraded HIFAR Containment Isolation System. (author)

A reliability analysis tool for SpaceWire network

Science.gov (United States)

Zhou, Qiang; Zhu, Longjiang; Fei, Haidong; Wang, Xingyou

2017-04-01

A SpaceWire is a standard for on-board satellite networks as the basis for future data-handling architectures. It is becoming more and more popular in space applications due to its technical advantages, including reliability, low power and fault protection, etc. High reliability is the vital issue for spacecraft. Therefore, it is very important to analyze and improve the reliability performance of the SpaceWire network. This paper deals with the problem of reliability modeling and analysis with SpaceWire network. According to the function division of distributed network, a reliability analysis method based on a task is proposed, the reliability analysis of every task can lead to the system reliability matrix, the reliability result of the network system can be deduced by integrating these entire reliability indexes in the matrix. With the method, we develop a reliability analysis tool for SpaceWire Network based on VC, where the computation schemes for reliability matrix and the multi-path-task reliability are also implemented. By using this tool, we analyze several cases on typical architectures. And the analytic results indicate that redundancy architecture has better reliability performance than basic one. In practical, the dual redundancy scheme has been adopted for some key unit, to improve the reliability index of the system or task. Finally, this reliability analysis tool will has a directive influence on both task division and topology selection in the phase of SpaceWire network system design.

Ethics and Cost-Benefit Analysis

DEFF Research Database (Denmark)

Arler, Finn

The purpose of this research report is threefold. Firstly, the author traces the origins and justification of cost-benefit analysis in moral and political philosophy. Secondly, he explain some of the basic features of cost-benefit analysis as a planning tool in a step-bystep presentation. Thirdly......, he presents and discusses some of the main ethical difficulties related to the use of cost-benefit analysis as a planning tool....

Cost benefit analysis vs. referenda

OpenAIRE

Martin J. Osborne; Matthew A. Turner

2007-01-01

We consider a planner who chooses between two possible public policies and ask whether a referendum or a cost benefit analysis leads to higher welfare. We find that a referendum leads to higher welfare than a cost benefit analyses in "common value" environments. Cost benefit analysis is better in "private value" environments.

Reliability Analysis of Adhesive Bonded Scarf Joints

DEFF Research Database (Denmark)

Kimiaeifar, Amin; Toft, Henrik Stensgaard; Lund, Erik

2012-01-01

element analysis (FEA). For the reliability analysis a design equation is considered which is related to a deterministic code-based design equation where reliability is secured by partial safety factors together with characteristic values for the material properties and loads. The failure criteria......A probabilistic model for the reliability analysis of adhesive bonded scarfed lap joints subjected to static loading is developed. It is representative for the main laminate in a wind turbine blade subjected to flapwise bending. The structural analysis is based on a three dimensional (3D) finite...... are formulated using a von Mises, a modified von Mises and a maximum stress failure criterion. The reliability level is estimated for the scarfed lap joint and this is compared with the target reliability level implicitly used in the wind turbine standard IEC 61400-1. A convergence study is performed to validate...

Reliability analysis and operator modelling

International Nuclear Information System (INIS)

Hollnagel, Erik

1996-01-01

The paper considers the state of operator modelling in reliability analysis. Operator models are needed in reliability analysis because operators are needed in process control systems. HRA methods must therefore be able to account both for human performance variability and for the dynamics of the interaction. A selected set of first generation HRA approaches is briefly described in terms of the operator model they use, their classification principle, and the actual method they propose. In addition, two examples of second generation methods are also considered. It is concluded that first generation HRA methods generally have very simplistic operator models, either referring to the time-reliability relationship or to elementary information processing concepts. It is argued that second generation HRA methods must recognise that cognition is embedded in a context, and be able to account for that in the way human reliability is analysed and assessed

Analysis of Parking Reliability Guidance of Urban Parking Variable Message Sign System

Directory of Open Access Journals (Sweden)

Zhenyu Mei

2012-01-01

Full Text Available Operators of parking guidance and information systems (PGIS often encounter difficulty in determining when and how to provide reliable car park availability information to drivers. Reliability has become a key factor to ensure the benefits of urban PGIS. The present paper is the first to define the guiding parking reliability of urban parking variable message signs (VMSs. By analyzing the parking choice under guiding and optional parking lots, a guiding parking reliability model was constructed. A mathematical program was formulated to determine the guiding parking reliability of VMS. The procedures were applied to a numerical example, and the factors that affect guiding reliability were analyzed. The quantitative changes of the parking berths and the display conditions of VMS were found to be the most important factors influencing guiding reliability. The parking guiding VMS achieved the best benefit when the parking supply was close to or was less than the demand. The combination of a guiding parking reliability model and parking choice behavior offers potential for PGIS operators to reduce traffic congestion in central city areas.

Culture Representation in Human Reliability Analysis

Energy Technology Data Exchange (ETDEWEB)

David Gertman; Julie Marble; Steven Novack

2006-12-01

Understanding human-system response is critical to being able to plan and predict mission success in the modern battlespace. Commonly, human reliability analysis has been used to predict failures of human performance in complex, critical systems. However, most human reliability methods fail to take culture into account. This paper takes an easily understood state of the art human reliability analysis method and extends that method to account for the influence of culture, including acceptance of new technology, upon performance. The cultural parameters used to modify the human reliability analysis were determined from two standard industry approaches to cultural assessment: Hofstede’s (1991) cultural factors and Davis’ (1989) technology acceptance model (TAM). The result is called the Culture Adjustment Method (CAM). An example is presented that (1) reviews human reliability assessment with and without cultural attributes for a Supervisory Control and Data Acquisition (SCADA) system attack, (2) demonstrates how country specific information can be used to increase the realism of HRA modeling, and (3) discusses the differences in human error probability estimates arising from cultural differences.

Reliability Analysis of a Steel Frame

Directory of Open Access Journals (Sweden)

M. Sýkora

2002-01-01

Full Text Available A steel frame with haunches is designed according to Eurocodes. The frame is exposed to self-weight, snow, and wind actions. Lateral-torsional buckling appears to represent the most critical criterion, which is considered as a basis for the limit state function. In the reliability analysis, the probabilistic models proposed by the Joint Committee for Structural Safety (JCSS are used for basic variables. The uncertainty model coefficients take into account the inaccuracy of the resistance model for the haunched girder and the inaccuracy of the action effect model. The time invariant reliability analysis is based on Turkstra's rule for combinations of snow and wind actions. The time variant analysis describes snow and wind actions by jump processes with intermittencies. Assuming a 50-year lifetime, the obtained values of the reliability index b vary within the range from 3.95 up to 5.56. The cross-profile IPE 330 designed according to Eurocodes seems to be adequate. It appears that the time invariant reliability analysis based on Turkstra's rule provides considerably lower values of b than those obtained by the time variant analysis.

Quantitative characterization of the reliability of simplex buses and stars to compare their benefits in fieldbuses

International Nuclear Information System (INIS)

Barranco, Manuel; Proenza, Julián; Almeida, Luís

2015-01-01

Fieldbuses targeted to highly dependable distributed embedded systems are shifting from bus to star topologies. Surprisingly, despite the efforts into this direction, engineers lack of analyses that quantitatively characterize the system reliability achievable by buses and stars. Thus, to guide engineers in developing adequate bus and star fieldbuses, this work models, quantifies and compares the system reliability provided by simplex buses and stars for the case of the Controller Area Network (CAN). It clarifies how relevant dependability-related aspects affect reliability, refuting some intuitive ideas, and revealing some previously unknown bus and star benefits. - Highlights: • SANs models that quantify the reliability of simplex buses/stars in fieldbuses. • Models cover system relevant dependability-related features abstracted in the literature. • Results refute intuitive ideas about buses and stars and show some unexpected effects. • Models and results can guide the design of reliable simplex bus/stars fieldbuses

An integrated approach to human reliability analysis -- decision analytic dynamic reliability model

International Nuclear Information System (INIS)

Holmberg, J.; Hukki, K.; Norros, L.; Pulkkinen, U.; Pyy, P.

1999-01-01

The reliability of human operators in process control is sensitive to the context. In many contemporary human reliability analysis (HRA) methods, this is not sufficiently taken into account. The aim of this article is that integration between probabilistic and psychological approaches in human reliability should be attempted. This is achieved first, by adopting such methods that adequately reflect the essential features of the process control activity, and secondly, by carrying out an interactive HRA process. Description of the activity context, probabilistic modeling, and psychological analysis form an iterative interdisciplinary sequence of analysis in which the results of one sub-task maybe input to another. The analysis of the context is carried out first with the help of a common set of conceptual tools. The resulting descriptions of the context promote the probabilistic modeling, through which new results regarding the probabilistic dynamics can be achieved. These can be incorporated in the context descriptions used as reference in the psychological analysis of actual performance. The results also provide new knowledge of the constraints of activity, by providing information of the premises of the operator's actions. Finally, the stochastic marked point process model gives a tool, by which psychological methodology may be interpreted and utilized for reliability analysis

Time-dependent reliability sensitivity analysis of motion mechanisms

International Nuclear Information System (INIS)

Wei, Pengfei; Song, Jingwen; Lu, Zhenzhou; Yue, Zhufeng

2016-01-01

Reliability sensitivity analysis aims at identifying the source of structure/mechanism failure, and quantifying the effects of each random source or their distribution parameters on failure probability or reliability. In this paper, the time-dependent parametric reliability sensitivity (PRS) analysis as well as the global reliability sensitivity (GRS) analysis is introduced for the motion mechanisms. The PRS indices are defined as the partial derivatives of the time-dependent reliability w.r.t. the distribution parameters of each random input variable, and they quantify the effect of the small change of each distribution parameter on the time-dependent reliability. The GRS indices are defined for quantifying the individual, interaction and total contributions of the uncertainty in each random input variable to the time-dependent reliability. The envelope function method combined with the first order approximation of the motion error function is introduced for efficiently estimating the time-dependent PRS and GRS indices. Both the time-dependent PRS and GRS analysis techniques can be especially useful for reliability-based design. This significance of the proposed methods as well as the effectiveness of the envelope function method for estimating the time-dependent PRS and GRS indices are demonstrated with a four-bar mechanism and a car rack-and-pinion steering linkage. - Highlights: • Time-dependent parametric reliability sensitivity analysis is presented. • Time-dependent global reliability sensitivity analysis is presented for mechanisms. • The proposed method is especially useful for enhancing the kinematic reliability. • An envelope method is introduced for efficiently implementing the proposed methods. • The proposed method is demonstrated by two real planar mechanisms.

Reliability and validity of risk analysis

International Nuclear Information System (INIS)

Aven, Terje; Heide, Bjornar

2009-01-01

In this paper we investigate to what extent risk analysis meets the scientific quality requirements of reliability and validity. We distinguish between two types of approaches within risk analysis, relative frequency-based approaches and Bayesian approaches. The former category includes both traditional statistical inference methods and the so-called probability of frequency approach. Depending on the risk analysis approach, the aim of the analysis is different, the results are presented in different ways and consequently the meaning of the concepts reliability and validity are not the same.

Structural Reliability Analysis of Wind Turbines: A Review

Directory of Open Access Journals (Sweden)

Zhiyu Jiang

2017-12-01

Full Text Available The paper presents a detailed review of the state-of-the-art research activities on structural reliability analysis of wind turbines between the 1990s and 2017. We describe the reliability methods including the first- and second-order reliability methods and the simulation reliability methods and show the procedure for and application areas of structural reliability analysis of wind turbines. Further, we critically review the various structural reliability studies on rotor blades, bottom-fixed support structures, floating systems and mechanical and electrical components. Finally, future applications of structural reliability methods to wind turbine designs are discussed.

Reliability analysis of reactor pressure vessel intensity

International Nuclear Information System (INIS)

Zheng Liangang; Lu Yongbo

2012-01-01

This paper performs the reliability analysis of reactor pressure vessel (RPV) with ANSYS. The analysis method include direct Monte Carlo Simulation method, Latin Hypercube Sampling, central composite design and Box-Behnken Matrix design. The RPV integrity reliability under given input condition is proposed. The result shows that the effects on the RPV base material reliability are internal press, allowable basic stress and elasticity modulus of base material in descending order, and the effects on the bolt reliability are allowable basic stress of bolt material, preload of bolt and internal press in descending order. (authors)

System reliability analysis with natural language and expert's subjectivity

International Nuclear Information System (INIS)

Onisawa, T.

1996-01-01

This paper introduces natural language expressions and expert's subjectivity to system reliability analysis. To this end, this paper defines a subjective measure of reliability and presents the method of the system reliability analysis using the measure. The subjective measure of reliability corresponds to natural language expressions of reliability estimation, which is represented by a fuzzy set defined on [0,1]. The presented method deals with the dependence among subsystems and employs parametrized operations of subjective measures of reliability which can reflect expert 's subjectivity towards the analyzed system. The analysis results are also expressed by linguistic terms. Finally this paper gives an example of the system reliability analysis by the presented method

Reliability analysis in intelligent machines

Science.gov (United States)

Mcinroy, John E.; Saridis, George N.

1990-01-01

Given an explicit task to be executed, an intelligent machine must be able to find the probability of success, or reliability, of alternative control and sensing strategies. By using concepts for information theory and reliability theory, new techniques for finding the reliability corresponding to alternative subsets of control and sensing strategies are proposed such that a desired set of specifications can be satisfied. The analysis is straightforward, provided that a set of Gaussian random state variables is available. An example problem illustrates the technique, and general reliability results are presented for visual servoing with a computed torque-control algorithm. Moreover, the example illustrates the principle of increasing precision with decreasing intelligence at the execution level of an intelligent machine.

STARS software tool for analysis of reliability and safety

International Nuclear Information System (INIS)

Poucet, A.; Guagnini, E.

1989-01-01

This paper reports on the STARS (Software Tool for the Analysis of Reliability and Safety) project aims at developing an integrated set of Computer Aided Reliability Analysis tools for the various tasks involved in systems safety and reliability analysis including hazard identification, qualitative analysis, logic model construction and evaluation. The expert system technology offers the most promising perspective for developing a Computer Aided Reliability Analysis tool. Combined with graphics and analysis capabilities, it can provide a natural engineering oriented environment for computer assisted reliability and safety modelling and analysis. For hazard identification and fault tree construction, a frame/rule based expert system is used, in which the deductive (goal driven) reasoning and the heuristic, applied during manual fault tree construction, is modelled. Expert system can explain their reasoning so that the analyst can become aware of the why and the how results are being obtained. Hence, the learning aspect involved in manual reliability and safety analysis can be maintained and improved

Advanced Reactor Passive System Reliability Demonstration Analysis for an External Event

Directory of Open Access Journals (Sweden)

Matthew Bucknor

2017-03-01

Full Text Available Many advanced reactor designs rely on passive systems to fulfill safety functions during accident sequences. These systems depend heavily on boundary conditions to induce a motive force, meaning the system can fail to operate as intended because of deviations in boundary conditions, rather than as the result of physical failures. Furthermore, passive systems may operate in intermediate or degraded modes. These factors make passive system operation difficult to characterize within a traditional probabilistic framework that only recognizes discrete operating modes and does not allow for the explicit consideration of time-dependent boundary conditions. Argonne National Laboratory has been examining various methodologies for assessing passive system reliability within a probabilistic risk assessment for a station blackout event at an advanced small modular reactor. This paper provides an overview of a passive system reliability demonstration analysis for an external event. Considering an earthquake with the possibility of site flooding, the analysis focuses on the behavior of the passive Reactor Cavity Cooling System following potential physical damage and system flooding. The assessment approach seeks to combine mechanistic and simulation-based methods to leverage the benefits of the simulation-based approach without the need to substantially deviate from conventional probabilistic risk assessment techniques. Although this study is presented as only an example analysis, the results appear to demonstrate a high level of reliability of the Reactor Cavity Cooling System (and the reactor system in general for the postulated transient event.

Advanced reactor passive system reliability demonstration analysis for an external event

Energy Technology Data Exchange (ETDEWEB)

Bucknor, Matthew; Grabaskas, David; Brunett, Acacia J.; Grelle, Austin [Argonne National Laboratory, Argonne (United States)

2017-03-15

Many advanced reactor designs rely on passive systems to fulfill safety functions during accident sequences. These systems depend heavily on boundary conditions to induce a motive force, meaning the system can fail to operate as intended because of deviations in boundary conditions, rather than as the result of physical failures. Furthermore, passive systems may operate in intermediate or degraded modes. These factors make passive system operation difficult to characterize within a traditional probabilistic framework that only recognizes discrete operating modes and does not allow for the explicit consideration of time-dependent boundary conditions. Argonne National Laboratory has been examining various methodologies for assessing passive system reliability within a probabilistic risk assessment for a station blackout event at an advanced small modular reactor. This paper provides an overview of a passive system reliability demonstration analysis for an external event. Considering an earthquake with the possibility of site flooding, the analysis focuses on the behavior of the passive Reactor Cavity Cooling System following potential physical damage and system flooding. The assessment approach seeks to combine mechanistic and simulation-based methods to leverage the benefits of the simulation-based approach without the need to substantially deviate from conventional probabilistic risk assessment techniques. Although this study is presented as only an example analysis, the results appear to demonstrate a high level of reliability of the Reactor Cavity Cooling System (and the reactor system in general) for the postulated transient event.

Advanced reactor passive system reliability demonstration analysis for an external event

International Nuclear Information System (INIS)

Bucknor, Matthew; Grabaskas, David; Brunett, Acacia J.; Grelle, Austin

2017-01-01

Many advanced reactor designs rely on passive systems to fulfill safety functions during accident sequences. These systems depend heavily on boundary conditions to induce a motive force, meaning the system can fail to operate as intended because of deviations in boundary conditions, rather than as the result of physical failures. Furthermore, passive systems may operate in intermediate or degraded modes. These factors make passive system operation difficult to characterize within a traditional probabilistic framework that only recognizes discrete operating modes and does not allow for the explicit consideration of time-dependent boundary conditions. Argonne National Laboratory has been examining various methodologies for assessing passive system reliability within a probabilistic risk assessment for a station blackout event at an advanced small modular reactor. This paper provides an overview of a passive system reliability demonstration analysis for an external event. Considering an earthquake with the possibility of site flooding, the analysis focuses on the behavior of the passive Reactor Cavity Cooling System following potential physical damage and system flooding. The assessment approach seeks to combine mechanistic and simulation-based methods to leverage the benefits of the simulation-based approach without the need to substantially deviate from conventional probabilistic risk assessment techniques. Although this study is presented as only an example analysis, the results appear to demonstrate a high level of reliability of the Reactor Cavity Cooling System (and the reactor system in general) for the postulated transient event

Life-Cycle Cost-Benefit Analysis

DEFF Research Database (Denmark)

Thoft-Christensen, Palle

2010-01-01

The future use of Life-Cycle Cost-Benefit (LCCB) analysis is discussed in this paper. A more complete analysis including not only the traditional factors and user costs, but also factors which are difficult to include in the analysis is needed in the future.......The future use of Life-Cycle Cost-Benefit (LCCB) analysis is discussed in this paper. A more complete analysis including not only the traditional factors and user costs, but also factors which are difficult to include in the analysis is needed in the future....

Analysis of Parking Reliability Guidance of Urban Parking Variable Message Sign System

OpenAIRE

Zhenyu Mei; Ye Tian; Dongping Li

2012-01-01

Operators of parking guidance and information systems (PGIS) often encounter difficulty in determining when and how to provide reliable car park availability information to drivers. Reliability has become a key factor to ensure the benefits of urban PGIS. The present paper is the first to define the guiding parking reliability of urban parking variable message signs (VMSs). By analyzing the parking choice under guiding and optional parking lots, a guiding parking reliability model was constru...

Bias in risk-benefit analysis

International Nuclear Information System (INIS)

Mazur, A.

1985-01-01

Risk-benefit analysis has become popular in the past decade as a means of improving decision making, especially in the area of technology policy. Here risk-benefit analysis is compared to other (equally defensible) approaches to decision making, showing how it favors some political interests more than others, and suggesting why it has recently come to the fore as a tool of political analysis. A considerable portion of the discussion concerns nuclear power. 6 references

Reliability analysis techniques for the design engineer

International Nuclear Information System (INIS)

Corran, E.R.; Witt, H.H.

1980-01-01

A fault tree analysis package is described that eliminates most of the housekeeping tasks involved in proceeding from the initial construction of a fault tree to the final stage of presenting a reliability analysis in a safety report. It is suitable for designers with relatively little training in reliability analysis and computer operation. Users can rapidly investigate the reliability implications of various options at the design stage, and evolve a system which meets specified reliability objectives. Later independent review is thus unlikely to reveal major shortcomings necessitating modification and projects delays. The package operates interactively allowing the user to concentrate on the creative task of developing the system fault tree, which may be modified and displayed graphically. For preliminary analysis system data can be derived automatically from a generic data bank. As the analysis procedes improved estimates of critical failure rates and test and maintenance schedules can be inserted. The computations are standard, - identification of minimal cut-sets, estimation of reliability parameters, and ranking of the effect of the individual component failure modes and system failure modes on these parameters. The user can vary the fault trees and data on-line, and print selected data for preferred systems in a form suitable for inclusion in safety reports. A case history is given - that of HIFAR containment isolation system. (author)

The benefits of integrating cost-benefit analysis and risk assessment

International Nuclear Information System (INIS)

Fisher, K.; Clarke-Whistler, K.

1995-01-01

It has increasingly been recognized that knowledge of risks in the absence of benefits and costs cannot dictate appropriate public policy choices. Recent evidence of this recognition includes the proposed EPA Risk Assessment and Cost-Benefit Analysis Act of 1995, a number of legislative changes in Canada and the US, and the increasing demand for field studies combining measures of impacts, risks, costs and benefits. Failure to consider relative environmental and human health risks, benefits, and costs in making public policy decisions has resulted in allocating scarce resources away from areas offering the highest levels of risk reduction and improvements in health and safety. The authors discuss the implications of not taking costs and benefits into account in addressing environmental risks, drawing on examples from both Canada and the US. The authors also present the results of their recent field work demonstrating the advantages of considering costs and benefits in making public policy and site remediation decisions, including a study on the benefits and costs of prevention, remediation and monitoring techniques applied to groundwater contamination; the benefits and costs of banning the use of chlorine; and the benefits and costs of Canada's concept of disposing of high-level nuclear waste. The authors conclude that a properly conducted Cost-Benefit Analysis can provide critical input to a Risk Assessment and can ensure that risk management decisions are efficient, cost-effective and maximize improvement to environmental and human health

Electric propulsion reliability: Statistical analysis of on-orbit anomalies and comparative analysis of electric versus chemical propulsion failure rates

Science.gov (United States)

Saleh, Joseph Homer; Geng, Fan; Ku, Michelle; Walker, Mitchell L. R.

2017-10-01

With a few hundred spacecraft launched to date with electric propulsion (EP), it is possible to conduct an epidemiological study of EP's on orbit reliability. The first objective of the present work was to undertake such a study and analyze EP's track record of on orbit anomalies and failures by different covariates. The second objective was to provide a comparative analysis of EP's failure rates with those of chemical propulsion. Satellite operators, manufacturers, and insurers will make reliability- and risk-informed decisions regarding the adoption and promotion of EP on board spacecraft. This work provides evidence-based support for such decisions. After a thorough data collection, 162 EP-equipped satellites launched between January 1997 and December 2015 were included in our dataset for analysis. Several statistical analyses were conducted, at the aggregate level and then with the data stratified by severity of the anomaly, by orbit type, and by EP technology. Mean Time To Anomaly (MTTA) and the distribution of the time to (minor/major) anomaly were investigated, as well as anomaly rates. The important findings in this work include the following: (1) Post-2005, EP's reliability has outperformed that of chemical propulsion; (2) Hall thrusters have robustly outperformed chemical propulsion, and they maintain a small but shrinking reliability advantage over gridded ion engines. Other results were also provided, for example the differentials in MTTA of minor and major anomalies for gridded ion engines and Hall thrusters. It was shown that: (3) Hall thrusters exhibit minor anomalies very early on orbit, which might be indicative of infant anomalies, and thus would benefit from better ground testing and acceptance procedures; (4) Strong evidence exists that EP anomalies (onset and likelihood) and orbit type are dependent, a dependence likely mediated by either the space environment or differences in thrusters duty cycles; (5) Gridded ion thrusters exhibit both

Human Reliability Analysis for Design: Using Reliability Methods for Human Factors Issues

Energy Technology Data Exchange (ETDEWEB)

Ronald Laurids Boring

2010-11-01

This paper reviews the application of human reliability analysis methods to human factors design issues. An application framework is sketched in which aspects of modeling typically found in human reliability analysis are used in a complementary fashion to the existing human factors phases of design and testing. The paper provides best achievable practices for design, testing, and modeling. Such best achievable practices may be used to evaluate and human system interface in the context of design safety certifications.

Human Reliability Analysis for Design: Using Reliability Methods for Human Factors Issues

International Nuclear Information System (INIS)

Boring, Ronald Laurids

2010-01-01

This paper reviews the application of human reliability analysis methods to human factors design issues. An application framework is sketched in which aspects of modeling typically found in human reliability analysis are used in a complementary fashion to the existing human factors phases of design and testing. The paper provides best achievable practices for design, testing, and modeling. Such best achievable practices may be used to evaluate and human system interface in the context of design safety certifications.

24 CFR 965.402 - Benefit/cost analysis.

Science.gov (United States)

2010-04-01

... 24 Housing and Urban Development 4 2010-04-01 2010-04-01 false Benefit/cost analysis. 965.402...-Owned Projects § 965.402 Benefit/cost analysis. (a) A benefit/cost analysis shall be made to determine... (Continued) OFFICE OF ASSISTANT SECRETARY FOR PUBLIC AND INDIAN HOUSING, DEPARTMENT OF HOUSING AND URBAN...

Cost benefit justification of nuclear plant reliability improvement

International Nuclear Information System (INIS)

El-Sayed, M.A.H.; Abdelmonem, N.M.

1985-01-01

The design of the secondary steam loop of the nuclear power plant has a significant effect on the reliability of the plant. Moreover, the necessity to cool a reactor safely has increased the reliability demanded from the system. The rapidly rising construction costs and fuel prices in recent years have stimulated a great deal in optimizing the productivity of a nuclear power plant through reliability improvement of the secondary steamloop and the reactor cooling system. A method for evaluating the reliability of steam loop and cooling system of a nuclear power plant is presented. The method utilizes the cut-set technique. The developed method can be easily used to show to what extent the overall reliability of the nuclear plant is affected by the possible failures in the steam and cooling subsystem. A model for calculating the increase in the nuclear plant productivity resulting from a proposed improvement in the two subsystems reliability is discussed. The model takes into account the capital cost of spare parts for several components, replacement energy, operating and maintenance costs

Systems reliability analysis for the national ignition facility

International Nuclear Information System (INIS)

Majumdar, K.C.; Annese, C.E.; MacIntyre, A.T.; Sicherman, A.

1996-01-01

A Reliability, Availability and Maintainability (RAM) analysis was initiated for the National Ignition Facility (NIF). The NIF is an inertial confinement fusion research facility designed to achieve controlled thermonuclear reaction; the preferred site for the NIF is the Lawrence Livermore National Laboratory (LLNL). The NIF RAM analysis has three purposes: (1) to allocate top level reliability and availability goals for the systems, (2) to develop an operability model for optimum maintainability, and (3) to determine the achievability of the allocated goals of the RAM parameters for the NIF systems and the facility operation as a whole. An allocation model assigns the reliability and availability goals for front line and support systems by a top-down approach; reliability analysis uses a bottom-up approach to determine the system reliability and availability from component level to system level

Mechanical reliability analysis of tubes intended for hydrocarbons

Energy Technology Data Exchange (ETDEWEB)

Nahal, Mourad; Khelif, Rabia [Badji Mokhtar University, Annaba (Algeria)

2013-02-15

Reliability analysis constitutes an essential phase in any study concerning reliability. Many industrialists evaluate and improve the reliability of their products during the development cycle - from design to startup (design, manufacture, and exploitation) - to develop their knowledge on cost/reliability ratio and to control sources of failure. In this study, we obtain results for hardness, tensile, and hydrostatic tests carried out on steel tubes for transporting hydrocarbons followed by statistical analysis. Results obtained allow us to conduct a reliability study based on resistance request. Thus, index of reliability is calculated and the importance of the variables related to the tube is presented. Reliability-based assessment of residual stress effects is applied to underground pipelines under a roadway, with and without active corrosion. Residual stress has been found to greatly increase probability of failure, especially in the early stages of pipe lifetime.

Reliability Analysis of Wind Turbines

DEFF Research Database (Denmark)

Toft, Henrik Stensgaard; Sørensen, John Dalsgaard

2008-01-01

In order to minimise the total expected life-cycle costs of a wind turbine it is important to estimate the reliability level for all components in the wind turbine. This paper deals with reliability analysis for the tower and blades of onshore wind turbines placed in a wind farm. The limit states...... consideres are in the ultimate limit state (ULS) extreme conditions in the standstill position and extreme conditions during operating. For wind turbines, where the magnitude of the loads is influenced by the control system, the ultimate limit state can occur in both cases. In the fatigue limit state (FLS......) the reliability level for a wind turbine placed in a wind farm is considered, and wake effects from neighbouring wind turbines is taken into account. An illustrative example with calculation of the reliability for mudline bending of the tower is considered. In the example the design is determined according...

Component reliability analysis for development of component reliability DB of Korean standard NPPs

International Nuclear Information System (INIS)

Choi, S. Y.; Han, S. H.; Kim, S. H.

2002-01-01

The reliability data of Korean NPP that reflects the plant specific characteristics is necessary for PSA and Risk Informed Application. We have performed a project to develop the component reliability DB and calculate the component reliability such as failure rate and unavailability. We have collected the component operation data and failure/repair data of Korean standard NPPs. We have analyzed failure data by developing a data analysis method which incorporates the domestic data situation. And then we have compared the reliability results with the generic data for the foreign NPPs

Reliability Analysis for Safety Grade PLC(POSAFE-Q)

International Nuclear Information System (INIS)

Choi, Kyung Chul; Song, Seung Whan; Park, Gang Min; Hwang, Sung Jae

2012-01-01

Safety Grade PLC(Programmable Logic Controller), POSAFE-Q, was developed recently in accordance with nuclear regulatory and requirements. In this paper, describe reliability analysis for digital safety grade PLC (especially POSAFE-Q). Reliability analysis scope is Prediction, Calculation of MTBF (Mean Time Between Failure), FMEA (Failure Mode Effect Analysis), PFD (Probability of Failure on Demand). (author)

Weibull distribution in reliability data analysis in nuclear power plant

International Nuclear Information System (INIS)

Ma Yingfei; Zhang Zhijian; Zhang Min; Zheng Gangyang

2015-01-01

Reliability is an important issue affecting each stage of the life cycle ranging from birth to death of a product or a system. The reliability engineering includes the equipment failure data processing, quantitative assessment of system reliability and maintenance, etc. Reliability data refers to the variety of data that describe the reliability of system or component during its operation. These data may be in the form of numbers, graphics, symbols, texts and curves. Quantitative reliability assessment is the task of the reliability data analysis. It provides the information related to preventing, detect, and correct the defects of the reliability design. Reliability data analysis under proceed with the various stages of product life cycle and reliability activities. Reliability data of Systems Structures and Components (SSCs) in Nuclear Power Plants is the key factor of probabilistic safety assessment (PSA); reliability centered maintenance and life cycle management. The Weibull distribution is widely used in reliability engineering, failure analysis, industrial engineering to represent manufacturing and delivery times. It is commonly used to model time to fail, time to repair and material strength. In this paper, an improved Weibull distribution is introduced to analyze the reliability data of the SSCs in Nuclear Power Plants. An example is given in the paper to present the result of the new method. The Weibull distribution of mechanical equipment for reliability data fitting ability is very strong in nuclear power plant. It's a widely used mathematical model for reliability analysis. The current commonly used methods are two-parameter and three-parameter Weibull distribution. Through comparison and analysis, the three-parameter Weibull distribution fits the data better. It can reflect the reliability characteristics of the equipment and it is more realistic to the actual situation. (author)

Development of cost-benefit analysis system

International Nuclear Information System (INIS)

Shiba, Tsuyoshi; Mishima, Tetsuya; Yuyama, Tomonori; Suzuki, Atsushi

2001-01-01

In order to promote the FDR development, it is necessary to see various benefits brought by introduction of FBR from multiple perspectives and have a good grasp of such benefits quantitatively and an adequate R and D investment scale which corresponds with them. In this study, the structured prototype in the previous study was improved to be able to perform cost-benefit analysis. An example of improvement made in the system is addition of subroutine used for comparison between new energy and benefits brought by introduction of FBR with special emphasis on addition of logic for analyzing externality about the new energy. Other improvement examples are modification of the Conventional Year Expense Ratio method of power generation cost to Average Durable Year Cost method, addition of database function and turning input data into database, and reviewing idea on cost by the type of waste material and price of uranium. The cost-benefit analysis system was also restructured utilizing Microsoft ACCESS so that it should have a data base function. As the result of the improvement mentioned above, we expect that the improved cost-benefit analysis system will have higher generality than the system before; therefore, great deal of benefits brought by application of the system in the future is expected. (author)

Reliability Analysis of Tubular Joints in Offshore Structures

DEFF Research Database (Denmark)

Thoft-Christensen, Palle; Sørensen, John Dalsgaard

1987-01-01

Reliability analysis of single tubular joints and offshore platforms with tubular joints is" presented. The failure modes considered are yielding, punching, buckling and fatigue failure. Element reliability as well as systems reliability approaches are used and illustrated by several examples....... Finally, optimal design of tubular.joints with reliability constraints is discussed and illustrated by an example....

Waste package reliability analysis

International Nuclear Information System (INIS)

Pescatore, C.; Sastre, C.

1983-01-01

Proof of future performance of a complex system such as a high-level nuclear waste package over a period of hundreds to thousands of years cannot be had in the ordinary sense of the word. The general method of probabilistic reliability analysis could provide an acceptable framework to identify, organize, and convey the information necessary to satisfy the criterion of reasonable assurance of waste package performance according to the regulatory requirements set forth in 10 CFR 60. General principles which may be used to evaluate the qualitative and quantitative reliability of a waste package design are indicated and illustrated with a sample calculation of a repository concept in basalt. 8 references, 1 table

Swimming pool reactor reliability and safety analysis

International Nuclear Information System (INIS)

Li Zhaohuan

1997-01-01

A reliability and safety analysis of Swimming Pool Reactor in China Institute of Atomic Energy is done by use of event/fault tree technique. The paper briefly describes the analysis model, analysis code and main results. Meanwhile it also describes the impact of unassigned operation status on safety, the estimation of effectiveness of defense tactics in maintenance against common cause failure, the effectiveness of recovering actions on the system reliability, the comparison of occurrence frequencies of the core damage by use of generic and specific data

Probabilistic risk assessment course documentation. Volume 3. System reliability and analysis techniques, Session A - reliability

International Nuclear Information System (INIS)

Lofgren, E.V.

1985-08-01

This course in System Reliability and Analysis Techniques focuses on the quantitative estimation of reliability at the systems level. Various methods are reviewed, but the structure provided by the fault tree method is used as the basis for system reliability estimates. The principles of fault tree analysis are briefly reviewed. Contributors to system unreliability and unavailability are reviewed, models are given for quantitative evaluation, and the requirements for both generic and plant-specific data are discussed. Also covered are issues of quantifying component faults that relate to the systems context in which the components are embedded. All reliability terms are carefully defined. 44 figs., 22 tabs

Benefit analysis of proposed information systems

OpenAIRE

Besore, Mark H.

1991-01-01

Approved for public release; distribution is unlimited This thesis reviewed two different approaches to benefit analysis, benefit comparison and user satisfaction, that could be applied to the evaluation of proposed information systems which are under consideration for acquisition by the federal government. Currently the General Services Administration only recommends that present value analysis methods be used in the analysis of alternatives even though the GSA specifies...

Analysis of employee satisfaction with benefits

OpenAIRE

Málková, Eliška

2013-01-01

This bachelor thesis is focused on an issue of providing employee benefits. The first part describes the benefits from a theoretical point of view, here is also mentioned a research about the benefits and an impact of the economic crisis on providing the benefits. The second part is focused on describing the benefits of a particular company, KOMIX Inc., an analysis of an employee satisfaction with the benefits with using a questionnaire survey and suggestion of ways to improve the current sys...

Regulatory analysis for the resolution of Generic Issue 115, enhancement of the reliability of the Westinghouse Solid State Protection System

International Nuclear Information System (INIS)

Basdekas, D.L.

1989-05-01

Generic Issue 115 addresses a concern related to the reliability of the Westinghouse reactor protection system for plants using the Westinghouse Solid State Protection System (SSPS). Several options for improving the reliability of the Westinghouse reactor trip function for these plants and their effect on core damage frequency (CDF) and overall risk were evaluated. This regulatory analysis includes a quantitative assessment of the costs and benefits associated with the various options for enhancing the reliability of the Westinghouse SSPS and provides insights for consideration and industry initiatives. No new regulatory requirements are proposed. 25 refs., 11 tabs

Human reliability analysis using event trees

International Nuclear Information System (INIS)

Heslinga, G.

1983-01-01

The shut-down procedure of a technologically complex installation as a nuclear power plant consists of a lot of human actions, some of which have to be performed several times. The procedure is regarded as a chain of modules of specific actions, some of which are analyzed separately. The analysis is carried out by making a Human Reliability Analysis event tree (HRA event tree) of each action, breaking down each action into small elementary steps. The application of event trees in human reliability analysis implies more difficulties than in the case of technical systems where event trees were mainly used until now. The most important reason is that the operator is able to recover a wrong performance; memory influences play a significant role. In this study these difficulties are dealt with theoretically. The following conclusions can be drawn: (1) in principle event trees may be used in human reliability analysis; (2) although in practice the operator will recover his fault partly, theoretically this can be described as starting the whole event tree again; (3) compact formulas have been derived, by which the probability of reaching a specific failure consequence on passing through the HRA event tree after several times of recovery is to be calculated. (orig.)

Fatigue Reliability Analysis of a Mono-Tower Platform

DEFF Research Database (Denmark)

Kirkegaard, Poul Henning; Sørensen, John Dalsgaard; Brincker, Rune

1991-01-01

In this paper, a fatigue reliability analysis of a Mono-tower platform is presented. The failure mode, fatigue failure in the butt welds, is investigated with two different models. The one with the fatigue strength expressed through SN relations, the other with the fatigue strength expressed thro...... of the natural period, damping ratio, current, stress spectrum and parameters describing the fatigue strength. Further, soil damping is shown to be significant for the Mono-tower.......In this paper, a fatigue reliability analysis of a Mono-tower platform is presented. The failure mode, fatigue failure in the butt welds, is investigated with two different models. The one with the fatigue strength expressed through SN relations, the other with the fatigue strength expressed...... through linear-elastic fracture mechanics (LEFM). In determining the cumulative fatigue damage, Palmgren-Miner's rule is applied. Element reliability, as well as systems reliability, is estimated using first-order reliability methods (FORM). The sensitivity of the systems reliability to various parameters...

Cost benefit analysis of power plant database integration

International Nuclear Information System (INIS)

Wilber, B.E.; Cimento, A.; Stuart, R.

1988-01-01

A cost benefit analysis of plant wide data integration allows utility management to evaluate integration and automation benefits from an economic perspective. With this evaluation, the utility can determine both the quantitative and qualitative savings that can be expected from data integration. The cost benefit analysis is then a planning tool which helps the utility to develop a focused long term implementation strategy that will yield significant near term benefits. This paper presents a flexible cost benefit analysis methodology which is both simple to use and yields accurate, verifiable results. Included in this paper is a list of parameters to consider, a procedure for performing the cost savings analysis, and samples of this procedure when applied to a utility. A case study is presented involving a specific utility where this procedure was applied. Their uses of the cost-benefit analysis are also described

Reliability Engineering Analysis of ATLAS Data Reprocessing Campaigns

CERN Document Server

Vaniachine, A; The ATLAS collaboration; Karpenko, D

2013-01-01

During three years of LHC data taking, the ATLAS collaboration completed three petascale data reprocessing campaigns on the Grid, with up to 2 PB of data being reprocessed every year. In reprocessing on the Grid, failures can occur for a variety of reasons, while Grid heterogeneity makes failures hard to diagnose and repair quickly. As a result, Big Data processing on the Grid must tolerate a continuous stream of failures, errors and faults. While ATLAS fault-tolerance mechanisms improve the reliability of Big Data processing in the Grid, their benefits come at costs and result in delays making the performance prediction difficult. Reliability Engineering provides a framework for fundamental understanding of the Big Data processing on the Grid, which is not a desirable enhancement but a necessary requirement. In ATLAS, cost monitoring and performance prediction became critical for the success of the reprocessing campaigns conducted in preparation for the major physics conferences. In addition, our Reliability...

Reliability Engineering Analysis of ATLAS Data Reprocessing Campaigns

CERN Document Server

Vaniachine, A; The ATLAS collaboration; Karpenko, D

2014-01-01

During three years of LHC data taking, the ATLAS collaboration completed three petascale data reprocessing campaigns on the Grid, with up to 2 PB of data being reprocessed every year. In reprocessing on the Grid, failures can occur for a variety of reasons, while Grid heterogeneity makes failures hard to diagnose and repair quickly. As a result, Big Data processing on the Grid must tolerate a continuous stream of failures, errors and faults. While ATLAS fault-tolerance mechanisms improve the reliability of Big Data processing in the Grid, their benefits come at costs and result in delays making the performance prediction difficult. Reliability Engineering provides a framework for fundamental understanding of the Big Data processing on the Grid, which is not a desirable enhancement but a necessary requirement. In ATLAS, cost monitoring and performance prediction became critical for the success of the reprocessing campaigns conducted in preparation for the major physics conferences. In addition, our Reliability...

Social cost-benefit analysis and nuclear futures

International Nuclear Information System (INIS)

Pearce, D.W.

1979-01-01

The usefulness of cost-benefit analysis in making nuclear power investment decisions is considered. The essence of social cost-benefit analysis is outlined and shown to be unavoidably value-laden. As a case study six issues relevant to the decision to build on oxide fuel reprocessing plant (THORP) are examined. The potential practical value of using cost-benefit analysis as an aid to decision-making is considered for each of these issues. It is concluded that cost-benefit approach is of limited value in the nuclear power case because of its inapplicability to such issues as the liberty of the individual and nuclear weapons proliferation. (author)

Prime implicants in dynamic reliability analysis

International Nuclear Information System (INIS)

Tyrväinen, Tero

2016-01-01

This paper develops an improved definition of a prime implicant for the needs of dynamic reliability analysis. Reliability analyses often aim to identify minimal cut sets or prime implicants, which are minimal conditions that cause an undesired top event, such as a system's failure. Dynamic reliability analysis methods take the time-dependent behaviour of a system into account. This means that the state of a component can change in the analysed time frame and prime implicants can include the failure of a component at different time points. There can also be dynamic constraints on a component's behaviour. For example, a component can be non-repairable in the given time frame. If a non-repairable component needs to be failed at a certain time point to cause the top event, we consider that the condition that it is failed at the latest possible time point is minimal, and the condition in which it fails earlier non-minimal. The traditional definition of a prime implicant does not account for this type of time-related minimality. In this paper, a new definition is introduced and illustrated using a dynamic flowgraph methodology model. - Highlights: • A new definition of a prime implicant is developed for dynamic reliability analysis. • The new definition takes time-related minimality into account. • The new definition is needed in dynamic flowgraph methodology. • Results can be represented by a smaller number of prime implicants.

Cost-benefit analysis: reality or illusion

International Nuclear Information System (INIS)

Tait, G.W.C.

1980-01-01

The problems encountered in the application of cost-benefit analysis to the setting of acceptable radiation exposure levels are discussed, in particular the difficulty of assigning a monetary value to human life or disability, and the fact that the customary optimization of cost-benefit is not consistent with the ICRP dose limitation system, especially the ALARA principle. It is concluded that the present ICRP recommendations should remain the basis of exposure control while a carefully limited use of cost-benefit analysis may be helpful in some cases. (U.K.)

Reliability Analysis of Elasto-Plastic Structures

DEFF Research Database (Denmark)

Thoft-Christensen, Palle; Sørensen, John Dalsgaard

1984-01-01

. Failure of this type of system is defined either as formation of a mechanism or by failure of a prescribed number of elements. In the first case failure is independent of the order in which the elements fail, but this is not so by the second definition. The reliability analysis consists of two parts...... are described and the two definitions of failure can be used by the first formulation, but only the failure definition based on formation of a mechanism by the second formulation. The second part of the reliability analysis is an estimate of the failure probability for the structure on the basis...

Bearing Procurement Analysis Method by Total Cost of Ownership Analysis and Reliability Prediction

Science.gov (United States)

Trusaji, Wildan; Akbar, Muhammad; Sukoyo; Irianto, Dradjad

2018-03-01

In making bearing procurement analysis, price and its reliability must be considered as decision criteria, since price determines the direct cost as acquisition cost and reliability of bearing determine the indirect cost such as maintenance cost. Despite the indirect cost is hard to identify and measured, it has high contribution to overall cost that will be incurred. So, the indirect cost of reliability must be considered when making bearing procurement analysis. This paper tries to explain bearing evaluation method with the total cost of ownership analysis to consider price and maintenance cost as decision criteria. Furthermore, since there is a lack of failure data when bearing evaluation phase is conducted, reliability prediction method is used to predict bearing reliability from its dynamic load rating parameter. With this method, bearing with a higher price but has higher reliability is preferable for long-term planning. But for short-term planning the cheaper one but has lower reliability is preferable. This contextuality can give rise to conflict between stakeholders. Thus, the planning horizon needs to be agreed by all stakeholder before making a procurement decision.

Reliability Analysis Techniques for Communication Networks in Nuclear Power Plant

International Nuclear Information System (INIS)

Lim, T. J.; Jang, S. C.; Kang, H. G.; Kim, M. C.; Eom, H. S.; Lee, H. J.

2006-09-01

The objectives of this project is to investigate and study existing reliability analysis techniques for communication networks in order to develop reliability analysis models for nuclear power plant's safety-critical networks. It is necessary to make a comprehensive survey of current methodologies for communication network reliability. Major outputs of this study are design characteristics of safety-critical communication networks, efficient algorithms for quantifying reliability of communication networks, and preliminary models for assessing reliability of safety-critical communication networks

Research review and development trends of human reliability analysis techniques

International Nuclear Information System (INIS)

Li Pengcheng; Chen Guohua; Zhang Li; Dai Licao

2011-01-01

Human reliability analysis (HRA) methods are reviewed. The theoretical basis of human reliability analysis, human error mechanism, the key elements of HRA methods as well as the existing HRA methods are respectively introduced and assessed. Their shortcomings,the current research hotspot and difficult problems are identified. Finally, it takes a close look at the trends of human reliability analysis methods. (authors)

Reliability analysis of grid connected small wind turbine power electronics

International Nuclear Information System (INIS)

Arifujjaman, Md.; Iqbal, M.T.; Quaicoe, J.E.

2009-01-01

Grid connection of small permanent magnet generator (PMG) based wind turbines requires a power conditioning system comprising a bridge rectifier, a dc-dc converter and a grid-tie inverter. This work presents a reliability analysis and an identification of the least reliable component of the power conditioning system of such grid connection arrangements. Reliability of the configuration is analyzed for the worst case scenario of maximum conversion losses at a particular wind speed. The analysis reveals that the reliability of the power conditioning system of such PMG based wind turbines is fairly low and it reduces to 84% of initial value within one year. The investigation is further enhanced by identifying the least reliable component within the power conditioning system and found that the inverter has the dominant effect on the system reliability, while the dc-dc converter has the least significant effect. The reliability analysis demonstrates that a permanent magnet generator based wind energy conversion system is not the best option from the point of view of power conditioning system reliability. The analysis also reveals that new research is required to determine a robust power electronics configuration for small wind turbine conversion systems.

Analysis of operating reliability of WWER-1000 unit

International Nuclear Information System (INIS)

Bortlik, J.

1985-01-01

The nuclear power unit was divided into 33 technological units. Input data for reliability analysis were surveys of operating results obtained from the IAEA information system and certain indexes of the reliability of technological equipment determined using the Bayes formula. The missing reliability data for technological equipment were used from the basic variant. The fault tree of the WWER-1000 unit was determined for the peak event defined as the impossibility of reaching 100%, 75% and 50% of rated power. The period was observed of the nuclear power plant operation with reduced output owing to defect and the respective time needed for a repair of the equipment. The calculation of the availability of the WWER-1000 unit was made for different variant situations. Certain indexes of the operating reliability of the WWER-1000 unit which are the result of a detailed reliability analysis are tabulated for selected variants. (E.S.)

Reliability analysis and assessment of structural systems

International Nuclear Information System (INIS)

Yao, J.T.P.; Anderson, C.A.

1977-01-01

The study of structural reliability deals with the probability of having satisfactory performance of the structure under consideration within any specific time period. To pursue this study, it is necessary to apply available knowledge and methodology in structural analysis (including dynamics) and design, behavior of materials and structures, experimental mechanics, and the theory of probability and statistics. In addition, various severe loading phenomena such as strong motion earthquakes and wind storms are important considerations. For three decades now, much work has been done on reliability analysis of structures, and during this past decade, certain so-called 'Level I' reliability-based design codes have been proposed and are in various stages of implementation. These contributions will be critically reviewed and summarized in this paper. Because of the undesirable consequences resulting from the failure of nuclear structures, it is important and desirable to consider the structural reliability in the analysis and design of these structures. Moreover, after these nuclear structures are constructed, it is desirable for engineers to be able to assess the structural reliability periodically as well as immediately following the occurrence of severe loading conditions such as a strong-motion earthquake. During this past decade, increasing use has been made of techniques of system identification in structural engineering. On the basis of non-destructive test results, various methods have been developed to obtain an adequate mathematical model (such as the equations of motion with more realistic parameters) to represent the structural system

Reliability analysis for wind turbines with incomplete failure data collected from after the date of initial installation

International Nuclear Information System (INIS)

Guo Haitao; Watson, Simon; Tavner, Peter; Xiang Jiangping

2009-01-01

Reliability has an impact on wind energy project costs and benefits. Both life test data and field failure data can be used for reliability analysis. In wind energy industry, wind farm operators have greater interest in recording wind turbine operating data. However, field failure data may be tainted or incomplete, and therefore it needs a more general mathematical model and algorithms to solve the model. The aim of this paper is to provide a solution to this problem. A three-parameter Weibull failure rate function is discussed for wind turbines and the parameters are estimated by maximum likelihood and least squares. Two populations of German and Danish wind turbines are analyzed. The traditional Weibull failure rate function is also employed for comparison. Analysis shows that the three-parameter Weibull function can obtain more accuracy on reliability growth of wind turbines. This work will be helpful in the understanding of the reliability growth of wind energy systems as wind energy technologies evolving. The proposed three-parameter Weibull function is also applicable to the life test of the components that have been used for a period of time, not only in wind energy but also in other industries

Analysis of the employee Benefits in Specific Organization

OpenAIRE

Procházková, Petra

2011-01-01

The main subject of my Bachelor's Thesis called "Analysis of employee Benefits in Specific Organization" is to analyze system of employee benefits used in company RWE Transgas, a. s. in 2010. Theoretical part will specify basic terms in general, which are important to cope with this issue. There will be especially importance, division, risks and trends in benefits. In practical part the analysis of employee benefits in specific joint-stock company is made. Part of this analysis is survey done...

Nurse manager succession planning: A cost-benefit analysis.

Science.gov (United States)

Phillips, Tracy; Evans, Jennifer L; Tooley, Stephanie; Shirey, Maria R

2018-03-01

This commentary presents a cost-benefit analysis to advocate for the use of succession planning to mitigate the problems ensuing from nurse manager turnover. An estimated 75% of nurse managers will leave the workforce by 2020. Many benefits are associated with proactively identifying and developing internal candidates. Fewer than 7% of health care organisations have implemented formal leadership succession planning programmes. A cost-benefit analysis of a formal succession-planning programme from one hospital illustrates the benefits of the programme in their organisation and can be replicated easily. Assumptions of nursing manager succession planning cost-benefit analysis are identified and discussed. The succession planning exemplar demonstrates the integration of cost-benefit analysis principles. Comparing the costs of a formal nurse manager succession planning strategy with the status quo results in a positive cost-benefit ratio. The implementation of a formal nurse manager succession planning programme effectively reduces replacement costs and time to transition into the new role. This programme provides an internal pipeline of future leaders who will be more successful than external candidates. Using an actual cost-benefit analysis equips nurse managers with valuable evidence depicting succession planning as a viable business strategy. © 2017 John Wiley & Sons Ltd.

Safety and reliability analysis based on nonprobabilistic methods

International Nuclear Information System (INIS)

Kozin, I.O.; Petersen, K.E.

1996-01-01

Imprecise probabilities, being developed during the last two decades, offer a considerably more general theory having many advantages which make it very promising for reliability and safety analysis. The objective of the paper is to argue that imprecise probabilities are more appropriate tool for reliability and safety analysis, that they allow to model the behavior of nuclear industry objects more comprehensively and give a possibility to solve some problems unsolved in the framework of conventional approach. Furthermore, some specific examples are given from which we can see the usefulness of the tool for solving some reliability tasks

Analysis of employee benefits in company

OpenAIRE

Burda, Tomáš

2011-01-01

The main subject of Bachelor's Thesis called "Analysis of employee benefits in company" is to analyze system of employee benefits used in company Saint-Gobain Construction Products a.s. The theoretical part focuses on the meaning of employee benefits, their categorization, terms of tax legislation a trends. In the practical section of the work, the current state of employee benefits in the firm is discussed and reviewed. A survey was conducted to investigate the satisfaction of employees towa...

System Reliability Analysis Considering Correlation of Performances

Energy Technology Data Exchange (ETDEWEB)

Kim, Saekyeol; Lee, Tae Hee [Hanyang Univ., Seoul (Korea, Republic of); Lim, Woochul [Mando Corporation, Seongnam (Korea, Republic of)

2017-04-15

Reliability analysis of a mechanical system has been developed in order to consider the uncertainties in the product design that may occur from the tolerance of design variables, uncertainties of noise, environmental factors, and material properties. In most of the previous studies, the reliability was calculated independently for each performance of the system. However, the conventional methods cannot consider the correlation between the performances of the system that may lead to a difference between the reliability of the entire system and the reliability of the individual performance. In this paper, the joint probability density function (PDF) of the performances is modeled using a copula which takes into account the correlation between performances of the system. The system reliability is proposed as the integral of joint PDF of performances and is compared with the individual reliability of each performance by mathematical examples and two-bar truss example.

System Reliability Analysis Considering Correlation of Performances

International Nuclear Information System (INIS)

Kim, Saekyeol; Lee, Tae Hee; Lim, Woochul

2017-01-01

Reliability analysis of a mechanical system has been developed in order to consider the uncertainties in the product design that may occur from the tolerance of design variables, uncertainties of noise, environmental factors, and material properties. In most of the previous studies, the reliability was calculated independently for each performance of the system. However, the conventional methods cannot consider the correlation between the performances of the system that may lead to a difference between the reliability of the entire system and the reliability of the individual performance. In this paper, the joint probability density function (PDF) of the performances is modeled using a copula which takes into account the correlation between performances of the system. The system reliability is proposed as the integral of joint PDF of performances and is compared with the individual reliability of each performance by mathematical examples and two-bar truss example.

Reliability analysis of digital based I and C system

Energy Technology Data Exchange (ETDEWEB)

Kang, I. S.; Cho, B. S.; Choi, M. J. [KOPEC, Yongin (Korea, Republic of)

1999-10-01

Rapidly, digital technology is being widely applied in replacing analog component installed in existing plant and designing new nuclear power plant for control and monitoring system in Korea as well as in foreign countries. Even though many merits of digital technology, it is being faced with a new problem of reliability assurance. The studies for solving this problem are being performed vigorously in foreign countries. The reliability of KNGR Engineered Safety Features Component Control System (ESF-CCS), digital based I and C system, was analyzed to verify fulfillment of the ALWR EPRI-URD requirement for reliability analysis and eliminate hazards in design applied new technology. The qualitative analysis using FMEA and quantitative analysis using reliability block diagram were performed. The results of analyses are shown in this paper.

Human reliability analysis of control room operators

Energy Technology Data Exchange (ETDEWEB)

Santos, Isaac J.A.L.; Carvalho, Paulo Victor R.; Grecco, Claudio H.S. [Instituto de Engenharia Nuclear (IEN), Rio de Janeiro, RJ (Brazil)

2005-07-01

Human reliability is the probability that a person correctly performs some system required action in a required time period and performs no extraneous action that can degrade the system Human reliability analysis (HRA) is the analysis, prediction and evaluation of work-oriented human performance using some indices as human error likelihood and probability of task accomplishment. Significant progress has been made in the HRA field during the last years, mainly in nuclear area. Some first-generation HRA methods were developed, as THERP (Technique for human error rate prediction). Now, an array of called second-generation methods are emerging as alternatives, for instance ATHEANA (A Technique for human event analysis). The ergonomics approach has as tool the ergonomic work analysis. It focus on the study of operator's activities in physical and mental form, considering at the same time the observed characteristics of operator and the elements of the work environment as they are presented to and perceived by the operators. The aim of this paper is to propose a methodology to analyze the human reliability of the operators of industrial plant control room, using a framework that includes the approach used by ATHEANA, THERP and the work ergonomics analysis. (author)

Development of RBDGG Solver and Its Application to System Reliability Analysis

International Nuclear Information System (INIS)

Kim, Man Cheol

2010-01-01

For the purpose of making system reliability analysis easier and more intuitive, RBDGG (Reliability Block diagram with General Gates) methodology was introduced as an extension of the conventional reliability block diagram. The advantage of the RBDGG methodology is that the structure of a RBDGG model is very similar to the actual structure of the analyzed system, and therefore the modeling of a system for system reliability and unavailability analysis becomes very intuitive and easy. The main idea of the development of the RBDGG methodology is similar with that of the development of the RGGG (Reliability Graph with General Gates) methodology, which is an extension of a conventional reliability graph. The newly proposed methodology is now implemented into a software tool, RBDGG Solver. RBDGG Solver was developed as a WIN32 console application. RBDGG Solver receives information on the failure modes and failure probabilities of each component in the system, along with the connection structure and connection logics among the components in the system. Based on the received information, RBDGG Solver automatically generates a system reliability analysis model for the system, and then provides the analysis results. In this paper, application of RBDGG Solver to the reliability analysis of an example system, and verification of the calculation results are provided for the purpose of demonstrating how RBDGG Solver is used for system reliability analysis

Risk-benefit analysis and public policy: a bibliography

Energy Technology Data Exchange (ETDEWEB)

Clark, E.M.; Van Horn, A.J.

1976-11-01

Risk-benefit analysis has been implicitly practiced whenever decision-makers are confronted with decisions involving risks to life, health, or to the environment. Various methodologies have been developed to evaluate relevant criteria and to aid in assessing the impacts of alternative projects. Among these have been cost-benefit analysis, which has been widely used for project evaluation. However, in many cases it has been difficult to assign dollar costs to those criteria involving risks and benefits which are not now assigned explicit monetary values in our economic system. Hence, risk-benefit analysis has evolved to become more than merely an extension of cost-benefit analysis, and many methods have been applied to examine the trade-offs between risks and benefits. In addition, new scientific and statistical techniques have been developed for assessing current and future risks. The 950 references included in this bibliography are meant to suggest the breadth of those methodologies which have been applied to decisions involving risk.

Risk-benefit analysis and public policy: a bibliography

International Nuclear Information System (INIS)

Clark, E.M.; Van Horn, A.J.

1976-11-01

Risk-benefit analysis has been implicitly practiced whenever decision-makers are confronted with decisions involving risks to life, health, or to the environment. Various methodologies have been developed to evaluate relevant criteria and to aid in assessing the impacts of alternative projects. Among these have been cost-benefit analysis, which has been widely used for project evaluation. However, in many cases it has been difficult to assign dollar costs to those criteria involving risks and benefits which are not now assigned explicit monetary values in our economic system. Hence, risk-benefit analysis has evolved to become more than merely an extension of cost-benefit analysis, and many methods have been applied to examine the trade-offs between risks and benefits. In addition, new scientific and statistical techniques have been developed for assessing current and future risks. The 950 references included in this bibliography are meant to suggest the breadth of those methodologies which have been applied to decisions involving risk

Cost-benefit analysis and non-utilitarian ethics

NARCIS (Netherlands)

Lowry, R.J.; Peterson, M.B.

2012-01-01

Cost-benefit analysis is commonly understood to be intimately connected with utilitarianism and incompatible with other moral theories, particularly those that focus on deontological concepts such as rights. We reject this claim and argue that cost-benefit analysis can take moral rights as well as

Advances in methods and applications of reliability and safety analysis

International Nuclear Information System (INIS)

Fieandt, J.; Hossi, H.; Laakso, K.; Lyytikaeinen, A.; Niemelae, I.; Pulkkinen, U.; Pulli, T.

1986-01-01

The know-how of the reliability and safety design and analysis techniques of Vtt has been established over several years in analyzing the reliability in the Finnish nuclear power plants Loviisa and Olkiluoto. This experience has been later on applied and developed to be used in the process industry, conventional power industry, automation and electronics. VTT develops and transfers methods and tools for reliability and safety analysis to the private and public sectors. The technology transfer takes place in joint development projects with potential users. Several computer-aided methods, such as RELVEC for reliability modelling and analysis, have been developed. The tool developed are today used by major Finnish companies in the fields of automation, nuclear power, shipbuilding and electronics. Development of computer-aided and other methods needed in analysis of operating experience, reliability or safety is further going on in a number of research and development projects

Human reliability analysis methods for probabilistic safety assessment

International Nuclear Information System (INIS)

Pyy, P.

2000-11-01

Human reliability analysis (HRA) of a probabilistic safety assessment (PSA) includes identifying human actions from safety point of view, modelling the most important of them in PSA models, and assessing their probabilities. As manifested by many incidents and studies, human actions may have both positive and negative effect on safety and economy. Human reliability analysis is one of the areas of probabilistic safety assessment (PSA) that has direct applications outside the nuclear industry. The thesis focuses upon developments in human reliability analysis methods and data. The aim is to support PSA by extending the applicability of HRA. The thesis consists of six publications and a summary. The summary includes general considerations and a discussion about human actions in the nuclear power plant (NPP) environment. A condensed discussion about the results of the attached publications is then given, including new development in methods and data. At the end of the summary part, the contribution of the publications to good practice in HRA is presented. In the publications, studies based on the collection of data on maintenance-related failures, simulator runs and expert judgement are presented in order to extend the human reliability analysis database. Furthermore, methodological frameworks are presented to perform a comprehensive HRA, including shutdown conditions, to study reliability of decision making, and to study the effects of wrong human actions. In the last publication, an interdisciplinary approach to analysing human decision making is presented. The publications also include practical applications of the presented methodological frameworks. (orig.)

Mathematical Methods in Survival Analysis, Reliability and Quality of Life

CERN Document Server

Huber, Catherine; Mesbah, Mounir

2008-01-01

Reliability and survival analysis are important applications of stochastic mathematics (probability, statistics and stochastic processes) that are usually covered separately in spite of the similarity of the involved mathematical theory. This title aims to redress this situation: it includes 21 chapters divided into four parts: Survival analysis, Reliability, Quality of life, and Related topics. Many of these chapters were presented at the European Seminar on Mathematical Methods for Survival Analysis, Reliability and Quality of Life in 2006.

Reliability analysis - systematic approach based on limited data

International Nuclear Information System (INIS)

Bourne, A.J.

1975-11-01

The initial approaches required for reliability analysis are outlined. These approaches highlight the system boundaries, examine the conditions under which the system is required to operate, and define the overall performance requirements. The discussion is illustrated by a simple example of an automatic protective system for a nuclear reactor. It is then shown how the initial approach leads to a method of defining the system, establishing performance parameters of interest and determining the general form of reliability models to be used. The overall system model and the availability of reliability data at the system level are next examined. An iterative process is then described whereby the reliability model and data requirements are systematically refined at progressively lower hierarchic levels of the system. At each stage, the approach is illustrated with examples from the protective system previously described. The main advantages of the approach put forward are the systematic process of analysis, the concentration of assessment effort in the critical areas and the maximum use of limited reliability data. (author)

Cost benefit analysis for optimization of radiation protection

International Nuclear Information System (INIS)

Lindell, B.

1984-01-01

ICRP recommends three basic principles for radiation protection. One is the justification of the source. Any use of radiation should be justified with regard to its benefit. The second is the optimization of radiation protection, i.e. all radiation exposure should be kept as low as resonably achievable. And the third principle is that there should be a limit for the radiation dose that any individual receives. Cost benefit assessment or cost benefit analysis is one tool to achieve the optimization, but the optimization is not identical with cost benefit analysis. Basically, in principle, the cost benefit analysis for the optimization of radiation protection is to find the minimum sum of the cost of protection and some cost of detriment. (Mori, K.)

Bayesian Inference for NASA Probabilistic Risk and Reliability Analysis

Science.gov (United States)

Dezfuli, Homayoon; Kelly, Dana; Smith, Curtis; Vedros, Kurt; Galyean, William

2009-01-01

This document, Bayesian Inference for NASA Probabilistic Risk and Reliability Analysis, is intended to provide guidelines for the collection and evaluation of risk and reliability-related data. It is aimed at scientists and engineers familiar with risk and reliability methods and provides a hands-on approach to the investigation and application of a variety of risk and reliability data assessment methods, tools, and techniques. This document provides both: A broad perspective on data analysis collection and evaluation issues. A narrow focus on the methods to implement a comprehensive information repository. The topics addressed herein cover the fundamentals of how data and information are to be used in risk and reliability analysis models and their potential role in decision making. Understanding these topics is essential to attaining a risk informed decision making environment that is being sought by NASA requirements and procedures such as 8000.4 (Agency Risk Management Procedural Requirements), NPR 8705.05 (Probabilistic Risk Assessment Procedures for NASA Programs and Projects), and the System Safety requirements of NPR 8715.3 (NASA General Safety Program Requirements).

Digital Processor Module Reliability Analysis of Nuclear Power Plant

International Nuclear Information System (INIS)

Lee, Sang Yong; Jung, Jae Hyun; Kim, Jae Ho; Kim, Sung Hun

2005-01-01

The system used in plant, military equipment, satellite, etc. consists of many electronic parts as control module, which requires relatively high reliability than other commercial electronic products. Specially, Nuclear power plant related to the radiation safety requires high safety and reliability, so most parts apply to Military-Standard level. Reliability prediction method provides the rational basis of system designs and also provides the safety significance of system operations. Thus various reliability prediction tools have been developed in recent decades, among of them, the MI-HDBK-217 method has been widely used as a powerful tool for the prediction. In this work, It is explained that reliability analysis work for Digital Processor Module (DPM, control module of SMART) is performed by Parts Stress Method based on MIL-HDBK-217F NOTICE2. We are using the Relex 7.6 of Relex software corporation, because reliability analysis process requires enormous part libraries and data for failure rate calculation

Review of some aspects of human reliability quantification

International Nuclear Information System (INIS)

Lydell, B.O.Y.; Spurgin, A.J.; Hannaman, G.W.; Lukic, Y.D.

1986-01-01

An area in systems reliability considered to be weak, is the characterization and quantification of the role of the operations and maintenance staff in combatting accidents. Several R and D programs are underway to improve the modeling of human interactions and some progress has been made. This paper describes a specific aspect of human reliability analysis which is referred to as modeling of cognitive processes. In particular, the basis for the so- called Human Cognitive Reliability (HCR) model is described and the focus is on its validation and on its benefits and limitations

Preliminary Analysis of LORAN-C System Reliability for Civil Aviation.

Science.gov (United States)

1981-09-01

overviev of the analysis technique. Section 3 describes the computerized LORAN-C coverage model which is used extensively in the reliability analysis...Xth Plenary Assembly, Geneva, 1963, published by International Telecomunications Union. S. Braff, R., Computer program to calculate a Karkov Chain Reliability Model, unpublished york, MITRE Corporation. A-1 I.° , 44J Ili *Y 0E 00 ...F i8 1110 Prelim inary Analysis of Program Engineering & LORAN’C System ReliabilityMaintenance Service i ~Washington. D.C.

Analysis of employee benefits in a certain company

OpenAIRE

Valderová, Lenka

2009-01-01

The aim of this bachelor's thesismis to present motivation, the employee benefits and possibilities of providing them by the employer. Next there will follow analysis of the provided employee benefits in a chosen company. The analysis should reveal if the company applies theoretical knowledge in providing the employee benefits into practical life to meet its employees satisfaction.

Reliability analysis of digital I and C systems at KAERI

International Nuclear Information System (INIS)

Kim, Man Cheol

2013-01-01

This paper provides an overview of the ongoing research activities on a reliability analysis of digital instrumentation and control (I and C) systems of nuclear power plants (NPPs) performed by the Korea Atomic Energy Research Institute (KAERI). The research activities include the development of a new safety-critical software reliability analysis method by integrating the advantages of existing software reliability analysis methods, a fault coverage estimation method based on fault injection experiments, and a new human reliability analysis method for computer-based main control rooms (MCRs) based on human performance data from the APR-1400 full-scope simulator. The research results are expected to be used to address various issues such as the licensing issues related to digital I and C probabilistic safety assessment (PSA) for advanced digital-based NPPs. (author)

Reliability analysis of stiff versus flexible piping

International Nuclear Information System (INIS)

Lu, S.C.

1985-01-01

The overall objective of this research project is to develop a technical basis for flexible piping designs which will improve piping reliability and minimize the use of pipe supports, snubbers, and pipe whip restraints. The current study was conducted to establish the necessary groundwork based on the piping reliability analysis. A confirmatory piping reliability assessment indicated that removing rigid supports and snubbers tends to either improve or affect very little the piping reliability. The authors then investigated a couple of changes to be implemented in Regulatory Guide (RG) 1.61 and RG 1.122 aimed at more flexible piping design. They concluded that these changes substantially reduce calculated piping responses and allow piping redesigns with significant reduction in number of supports and snubbers without violating ASME code requirements. Furthermore, the more flexible piping redesigns are capable of exhibiting reliability levels equal to or higher than the original stiffer design. An investigation of the malfunction of pipe whip restraints confirmed that the malfunction introduced higher thermal stresses and tended to reduce the overall piping reliability. Finally, support and component reliabilities were evaluated based on available fragility data. Results indicated that the support reliability usually exhibits a moderate decrease as the piping flexibility increases. Most on-line pumps and valves showed an insignificant reduction in reliability for a more flexible piping design

Reliability analysis for Atucha II reactor protection system signals

International Nuclear Information System (INIS)

Roca, Jose Luis

1996-01-01

Atucha II is a 745 MW Argentine Power Nuclear Reactor constructed by ENACE SA, Nuclear Argentine Company for Electrical Power Generation and SIEMENS AG KWU, Erlangen, Germany. A preliminary modular logic analysis of RPS (Reactor Protection System) signals was performed by means of the well known Swedish professional risk and reliability software named Risk-Spectrum taking as a basis a reference signal coded as JR17ER003 which command the two moderator loops valves. From the reliability and behavior knowledge for this reference signal follows an estimation of the reliability for the other 97 RPS signals. Because the preliminary character of this analysis Main Important Measures are not performed at this stage. Reliability is by the statistic value named unavailability predicted. The scope of this analysis is restricted from the measurement elements to the RPS buffer outputs. In the present context only one redundancy is analyzed so in the Instrumentation and Control area there no CCF (Common Cause Failures) present for signals. Finally those unavailability values could be introduced in the failure domain for the posterior complete Atucha II reliability analysis which includes all mechanical and electromechanical features. Also an estimation of the spurious frequency of RPS signals defined as faulty by no trip is performed

Reliability analysis for Atucha II reactor protection system signals

International Nuclear Information System (INIS)

Roca, Jose L.

2000-01-01

Atucha II is a 745 MW Argentine power nuclear reactor constructed by Nuclear Argentine Company for Electric Power Generation S.A. (ENACE S.A.) and SIEMENS AG KWU, Erlangen, Germany. A preliminary modular logic analysis of RPS (Reactor Protection System) signals was performed by means of the well known Swedish professional risk and reliability software named Risk-Spectrum taking as a basis a reference signal coded as JR17ER003 which command the two moderator loops valves. From the reliability and behavior knowledge for this reference signal follows an estimation of the reliability for the other 97 RPS signals. Because the preliminary character of this analysis Main Important Measures are not performed at this stage. Reliability is by the statistic value named unavailability predicted. The scope of this analysis is restricted from the measurement elements to the RPS buffer outputs. In the present context only one redundancy is analyzed so in the Instrumentation and Control area there no CCF (Common Cause Failures) present for signals. Finally those unavailability values could be introduced in the failure domain for the posterior complete Atucha II reliability analysis which includes all mechanical and electromechanical features. Also an estimation of the spurious frequency of RPS signals defined as faulty by no trip is performed. (author)

Interactive reliability analysis project. FY 80 progress report

International Nuclear Information System (INIS)

Rasmuson, D.M.; Shepherd, J.C.

1981-03-01

This report summarizes the progress to date in the interactive reliability analysis project. Purpose is to develop and demonstrate a reliability and safety technique that can be incorporated early in the design process. Details are illustrated in a simple example of a reactor safety system

Accident Sequence Evaluation Program: Human reliability analysis procedure

International Nuclear Information System (INIS)

Swain, A.D.

1987-02-01

This document presents a shortened version of the procedure, models, and data for human reliability analysis (HRA) which are presented in the Handbook of Human Reliability Analysis With emphasis on Nuclear Power Plant Applications (NUREG/CR-1278, August 1983). This shortened version was prepared and tried out as part of the Accident Sequence Evaluation Program (ASEP) funded by the US Nuclear Regulatory Commission and managed by Sandia National Laboratories. The intent of this new HRA procedure, called the ''ASEP HRA Procedure,'' is to enable systems analysts, with minimal support from experts in human reliability analysis, to make estimates of human error probabilities and other human performance characteristics which are sufficiently accurate for many probabilistic risk assessments. The ASEP HRA Procedure consists of a Pre-Accident Screening HRA, a Pre-Accident Nominal HRA, a Post-Accident Screening HRA, and a Post-Accident Nominal HRA. The procedure in this document includes changes made after tryout and evaluation of the procedure in four nuclear power plants by four different systems analysts and related personnel, including human reliability specialists. The changes consist of some additional explanatory material (including examples), and more detailed definitions of some of the terms. 42 refs

78 FR 45447 - Revisions to Modeling, Data, and Analysis Reliability Standard

Science.gov (United States)

2013-07-29

...; Order No. 782] Revisions to Modeling, Data, and Analysis Reliability Standard AGENCY: Federal Energy... Analysis (MOD) Reliability Standard MOD- 028-2, submitted to the Commission for approval by the North... Organization. The Commission finds that the proposed Reliability Standard represents an improvement over the...

State of the art report on aging reliability analysis

International Nuclear Information System (INIS)

Choi, Sun Yeong; Yang, Joon Eon; Han, Sang Hoon; Ha, Jae Joo

2002-03-01

The goal of this report is to describe the state of the art on aging analysis methods to calculate the effects of component aging quantitatively. In this report, we described some aging analysis methods which calculate the increase of Core Damage Frequency (CDF) due to aging by including the influence of aging into PSA. We also described several research topics required for aging analysis for components of domestic NPPs. We have described a statistical model and reliability physics model which calculate the effect of aging quantitatively by using PSA method. It is expected that the practical use of the reliability-physics model will be increased though the process with the reliability-physics model is more complicated than statistical model

Reliability of the Emergency Severity Index: Meta-analysis

Directory of Open Access Journals (Sweden)

Amir Mirhaghi

2015-01-01

Full Text Available Objectives: Although triage systems based on the Emergency Severity Index (ESI have many advantages in terms of simplicity and clarity, previous research has questioned their reliability in practice. Therefore, the aim of this meta-analysis was to determine the reliability of ESI triage scales. Methods: This metaanalysis was performed in March 2014. Electronic research databases were searched and articles conforming to the Guidelines for Reporting Reliability and Agreement Studies were selected. Two researchers independently examined selected abstracts. Data were extracted in the following categories: version of scale (latest/older, participants (adult/paediatric, raters (nurse, physician or expert, method of reliability (intra/inter-rater, reliability statistics (weighted/unweighted kappa and the origin and publication year of the study. The effect size was obtained by the Z-transformation of reliability coefficients. Data were pooled with random-effects models and a meta-regression was performed based on the method of moments estimator. Results: A total of 19 studies from six countries were included in the analysis. The pooled coefficient for the ESI triage scales was substantial at 0.791 (95% confidence interval: 0.787‒0.795. Agreement was higher with the latest and adult versions of the scale and among expert raters, compared to agreement with older and paediatric versions of the scales and with other groups of raters, respectively. Conclusion: ESI triage scales showed an acceptable level of overall reliability. However, ESI scales require more development in order to see full agreement from all rater groups. Further studies concentrating on other aspects of reliability assessment are needed.

The Aviation System Analysis Capability Air Carrier Cost-Benefit Model

Science.gov (United States)

Gaier, Eric M.; Edlich, Alexander; Santmire, Tara S.; Wingrove, Earl R.., III

1999-01-01

To meet its objective of assisting the U.S. aviation industry with the technological challenges of the future, NASA must identify research areas that have the greatest potential for improving the operation of the air transportation system. Therefore, NASA is developing the ability to evaluate the potential impact of various advanced technologies. By thoroughly understanding the economic impact of advanced aviation technologies and by evaluating how the new technologies will be used in the integrated aviation system, NASA aims to balance its aeronautical research program and help speed the introduction of high-leverage technologies. To meet these objectives, NASA is building the Aviation System Analysis Capability (ASAC). NASA envisions ASAC primarily as a process for understanding and evaluating the impact of advanced aviation technologies on the U.S. economy. ASAC consists of a diverse collection of models and databases used by analysts and other individuals from the public and private sectors brought together to work on issues of common interest to organizations in the aviation community. ASAC also will be a resource available to the aviation community to analyze; inform; and assist scientists, engineers, analysts, and program managers in their daily work. The ASAC differs from previous NASA modeling efforts in that the economic behavior of buyers and sellers in the air transportation and aviation industries is central to its conception. Commercial air carriers, in particular, are an important stakeholder in this community. Therefore, to fully evaluate the implications of advanced aviation technologies, ASAC requires a flexible financial analysis tool that credibly links the technology of flight with the financial performance of commercial air carriers. By linking technical and financial information, NASA ensures that its technology programs will continue to benefit the user community. In addition, the analysis tool must be capable of being incorporated into the

Reliability analysis in interdependent smart grid systems

Science.gov (United States)

Peng, Hao; Kan, Zhe; Zhao, Dandan; Han, Jianmin; Lu, Jianfeng; Hu, Zhaolong

2018-06-01

Complex network theory is a useful way to study many real complex systems. In this paper, a reliability analysis model based on complex network theory is introduced in interdependent smart grid systems. In this paper, we focus on understanding the structure of smart grid systems and studying the underlying network model, their interactions, and relationships and how cascading failures occur in the interdependent smart grid systems. We propose a practical model for interdependent smart grid systems using complex theory. Besides, based on percolation theory, we also study the effect of cascading failures effect and reveal detailed mathematical analysis of failure propagation in such systems. We analyze the reliability of our proposed model caused by random attacks or failures by calculating the size of giant functioning components in interdependent smart grid systems. Our simulation results also show that there exists a threshold for the proportion of faulty nodes, beyond which the smart grid systems collapse. Also we determine the critical values for different system parameters. In this way, the reliability analysis model based on complex network theory can be effectively utilized for anti-attack and protection purposes in interdependent smart grid systems.

Adjoint sensitivity analysis of dynamic reliability models based on Markov chains - II: Application to IFMIF reliability assessment

Energy Technology Data Exchange (ETDEWEB)

Cacuci, D. G. [Commiss Energy Atom, Direct Energy Nucl, Saclay, (France); Cacuci, D. G.; Balan, I. [Univ Karlsruhe, Inst Nucl Technol and Reactor Safetly, Karlsruhe, (Germany); Ionescu-Bujor, M. [Forschungszentrum Karlsruhe, Fus Program, D-76021 Karlsruhe, (Germany)

2008-07-01

In Part II of this work, the adjoint sensitivity analysis procedure developed in Part I is applied to perform sensitivity analysis of several dynamic reliability models of systems of increasing complexity, culminating with the consideration of the International Fusion Materials Irradiation Facility (IFMIF) accelerator system. Section II presents the main steps of a procedure for the automated generation of Markov chains for reliability analysis, including the abstraction of the physical system, construction of the Markov chain, and the generation and solution of the ensuing set of differential equations; all of these steps have been implemented in a stand-alone computer code system called QUEFT/MARKOMAG-S/MCADJSEN. This code system has been applied to sensitivity analysis of dynamic reliability measures for a paradigm '2-out-of-3' system comprising five components and also to a comprehensive dynamic reliability analysis of the IFMIF accelerator system facilities for the average availability and, respectively, the system's availability at the final mission time. The QUEFT/MARKOMAG-S/MCADJSEN has been used to efficiently compute sensitivities to 186 failure and repair rates characterizing components and subsystems of the first-level fault tree of the IFMIF accelerator system. (authors)

Adjoint sensitivity analysis of dynamic reliability models based on Markov chains - II: Application to IFMIF reliability assessment

International Nuclear Information System (INIS)

Cacuci, D. G.; Cacuci, D. G.; Balan, I.; Ionescu-Bujor, M.

2008-01-01

In Part II of this work, the adjoint sensitivity analysis procedure developed in Part I is applied to perform sensitivity analysis of several dynamic reliability models of systems of increasing complexity, culminating with the consideration of the International Fusion Materials Irradiation Facility (IFMIF) accelerator system. Section II presents the main steps of a procedure for the automated generation of Markov chains for reliability analysis, including the abstraction of the physical system, construction of the Markov chain, and the generation and solution of the ensuing set of differential equations; all of these steps have been implemented in a stand-alone computer code system called QUEFT/MARKOMAG-S/MCADJSEN. This code system has been applied to sensitivity analysis of dynamic reliability measures for a paradigm '2-out-of-3' system comprising five components and also to a comprehensive dynamic reliability analysis of the IFMIF accelerator system facilities for the average availability and, respectively, the system's availability at the final mission time. The QUEFT/MARKOMAG-S/MCADJSEN has been used to efficiently compute sensitivities to 186 failure and repair rates characterizing components and subsystems of the first-level fault tree of the IFMIF accelerator system. (authors)

A reliability simulation language for reliability analysis

International Nuclear Information System (INIS)

Deans, N.D.; Miller, A.J.; Mann, D.P.

1986-01-01

The results of work being undertaken to develop a Reliability Description Language (RDL) which will enable reliability analysts to describe complex reliability problems in a simple, clear and unambiguous way are described. Component and system features can be stated in a formal manner and subsequently used, along with control statements to form a structured program. The program can be compiled and executed on a general-purpose computer or special-purpose simulator. (DG)

Durability reliability analysis for corroding concrete structures under uncertainty

Science.gov (United States)

Zhang, Hao

2018-02-01

This paper presents a durability reliability analysis of reinforced concrete structures subject to the action of marine chloride. The focus is to provide insight into the role of epistemic uncertainties on durability reliability. The corrosion model involves a number of variables whose probabilistic characteristics cannot be fully determined due to the limited availability of supporting data. All sources of uncertainty, both aleatory and epistemic, should be included in the reliability analysis. Two methods are available to formulate the epistemic uncertainty: the imprecise probability-based method and the purely probabilistic method in which the epistemic uncertainties are modeled as random variables. The paper illustrates how the epistemic uncertainties are modeled and propagated in the two methods, and shows how epistemic uncertainties govern the durability reliability.

A methodology to incorporate organizational factors into human reliability analysis

International Nuclear Information System (INIS)

Li Pengcheng; Chen Guohua; Zhang Li; Xiao Dongsheng

2010-01-01

A new holistic methodology for Human Reliability Analysis (HRA) is proposed to model the effects of the organizational factors on the human reliability. Firstly, a conceptual framework is built, which is used to analyze the causal relationships between the organizational factors and human reliability. Then, the inference model for Human Reliability Analysis is built by combining the conceptual framework with Bayesian networks, which is used to execute the causal inference and diagnostic inference of human reliability. Finally, a case example is presented to demonstrate the specific application of the proposed methodology. The results show that the proposed methodology of combining the conceptual model with Bayesian Networks can not only easily model the causal relationship between organizational factors and human reliability, but in a given context, people can quantitatively measure the human operational reliability, and identify the most likely root causes or the prioritization of root causes caused human error. (authors)

Structural reliability analysis based on the cokriging technique

International Nuclear Information System (INIS)

Zhao Wei; Wang Wei; Dai Hongzhe; Xue Guofeng

2010-01-01

Approximation methods are widely used in structural reliability analysis because they are simple to create and provide explicit functional relationships between the responses and variables in stead of the implicit limit state function. Recently, the kriging method which is a semi-parameter interpolation technique that can be used for deterministic optimization and structural reliability has gained popularity. However, to fully exploit the kriging method, especially in high-dimensional problems, a large number of sample points should be generated to fill the design space and this can be very expensive and even impractical in practical engineering analysis. Therefore, in this paper, a new method-the cokriging method, which is an extension of kriging, is proposed to calculate the structural reliability. cokriging approximation incorporates secondary information such as the values of the gradients of the function being approximated. This paper explores the use of the cokriging method for structural reliability problems by comparing it with the Kriging method based on some numerical examples. The results indicate that the cokriging procedure described in this work can generate approximation models to improve on the accuracy and efficiency for structural reliability problems and is a viable alternative to the kriging.

Assessment of modern methods of human factor reliability analysis in PSA studies

International Nuclear Information System (INIS)

Holy, J.

2001-12-01

The report is structured as follows: Classical terms and objects (Probabilistic safety assessment as a framework for human reliability assessment; Human failure within the PSA model; Basic types of operator failure modelled in a PSA study and analyzed by HRA methods; Qualitative analysis of human reliability; Quantitative analysis of human reliability used; Process of analysis of nuclear reactor operator reliability in a PSA study); New terms and objects (Analysis of dependences; Errors of omission; Errors of commission; Error forcing context); and Overview and brief assessment of human reliability analysis (Basic characteristics of the methods; Assets and drawbacks of the use of each of HRA method; History and prospects of the use of the methods). (P.A.)

Reliability analysis of Angra I safety systems

International Nuclear Information System (INIS)

Oliveira, L.F.S. de; Soto, J.B.; Maciel, C.C.; Gibelli, S.M.O.; Fleming, P.V.; Arrieta, L.A.

1980-07-01

An extensive reliability analysis of some safety systems of Angra I, are presented. The fault tree technique, which has been successfully used in most reliability studies of nuclear safety systems performed to date is employed. Results of a quantitative determination of the unvailability of the accumulator and the containment spray injection systems are presented. These results are also compared to those reported in WASH-1400. (E.G.) [pt

Combined multi-criteria and cost-benefit analysis

DEFF Research Database (Denmark)

Moshøj, Claus Rehfeld

1996-01-01

The paper is an introduction to both theory and application of combined Cost-Benefit and Multi-Criteria Analysis. The first section is devoted to basic utility theory and its practical application in Cost-Benefit Analysis. Based on some of the problems encountered, arguments in favour...... of the application of utility-based Multi-Criteria Analyses methods as an extension and refinement of the traditional Cost-Benefit Analysis are provided. The theory presented in this paper is closely related the methods used in the WARP software (Leleur & Jensen, 1989). The presentation is however wider in scope.......The second section introduces the stated preference methodology used in WARP to create weight profiles for project pool sensitivity analysis. This section includes a simple example. The third section discusses how decision makers can get a priori aid to make their pair-wise comparisons based on project pool...

Reliability analysis of RC containment structures under combined loads

International Nuclear Information System (INIS)

Hwang, H.; Reich, M.; Kagami, S.

1984-01-01

This paper discusses a reliability analysis method and load combination design criteria for reinforced concrete containment structures under combined loads. The probability based reliability analysis method is briefly described. For load combination design criteria, derivations of the load factors for accidental pressure due to a design basis accident and safe shutdown earthquake (SSE) for three target limit state probabilities are presented

IEEE guide for the analysis of human reliability

International Nuclear Information System (INIS)

Dougherty, E.M. Jr.

1987-01-01

The Institute of Electrical and Electronics Engineers (IEEE) working group 7.4 of the Human Factors and Control Facilities Subcommittee of the Nuclear Power Engineering Committee (NPEC) has released its fifth draft of a Guide for General Principles of Human Action Reliability Analysis for Nuclear Power Generating Stations, for approval of NPEC. A guide is the least mandating in the IEEE hierarchy of standards. The purpose is to enhance the performance of an human reliability analysis (HRA) as a part of a probabilistic risk assessment (PRA), to assure reproducible results, and to standardize documentation. The guide does not recommend or even discuss specific techniques, which are too rapidly evolving today. Considerable maturation in the analysis of human reliability in a PRA context has taken place in recent years. The IEEE guide on this subject is an initial step toward bringing HRA out of the research and development arena into the toolbox of standard engineering practices

Discrete event simulation versus conventional system reliability analysis approaches

DEFF Research Database (Denmark)

Kozine, Igor

2010-01-01

Discrete Event Simulation (DES) environments are rapidly developing and appear to be promising tools for building reliability and risk analysis models of safety-critical systems and human operators. If properly developed, they are an alternative to the conventional human reliability analysis models...... and systems analysis methods such as fault and event trees and Bayesian networks. As one part, the paper describes briefly the author’s experience in applying DES models to the analysis of safety-critical systems in different domains. The other part of the paper is devoted to comparing conventional approaches...

Sensitivity analysis in a structural reliability context

International Nuclear Information System (INIS)

Lemaitre, Paul

2014-01-01

This thesis' subject is sensitivity analysis in a structural reliability context. The general framework is the study of a deterministic numerical model that allows to reproduce a complex physical phenomenon. The aim of a reliability study is to estimate the failure probability of the system from the numerical model and the uncertainties of the inputs. In this context, the quantification of the impact of the uncertainty of each input parameter on the output might be of interest. This step is called sensitivity analysis. Many scientific works deal with this topic but not in the reliability scope. This thesis' aim is to test existing sensitivity analysis methods, and to propose more efficient original methods. A bibliographical step on sensitivity analysis on one hand and on the estimation of small failure probabilities on the other hand is first proposed. This step raises the need to develop appropriate techniques. Two variables ranking methods are then explored. The first one proposes to make use of binary classifiers (random forests). The second one measures the departure, at each step of a subset method, between each input original density and the density given the subset reached. A more general and original methodology reflecting the impact of the input density modification on the failure probability is then explored. The proposed methods are then applied on the CWNR case, which motivates this thesis. (author)

Accident Sequence Evaluation Program: Human reliability analysis procedure

Energy Technology Data Exchange (ETDEWEB)

Swain, A.D.

1987-02-01

This document presents a shortened version of the procedure, models, and data for human reliability analysis (HRA) which are presented in the Handbook of Human Reliability Analysis With emphasis on Nuclear Power Plant Applications (NUREG/CR-1278, August 1983). This shortened version was prepared and tried out as part of the Accident Sequence Evaluation Program (ASEP) funded by the US Nuclear Regulatory Commission and managed by Sandia National Laboratories. The intent of this new HRA procedure, called the ''ASEP HRA Procedure,'' is to enable systems analysts, with minimal support from experts in human reliability analysis, to make estimates of human error probabilities and other human performance characteristics which are sufficiently accurate for many probabilistic risk assessments. The ASEP HRA Procedure consists of a Pre-Accident Screening HRA, a Pre-Accident Nominal HRA, a Post-Accident Screening HRA, and a Post-Accident Nominal HRA. The procedure in this document includes changes made after tryout and evaluation of the procedure in four nuclear power plants by four different systems analysts and related personnel, including human reliability specialists. The changes consist of some additional explanatory material (including examples), and more detailed definitions of some of the terms. 42 refs.

Cost-benefit analysis of FBR program

Energy Technology Data Exchange (ETDEWEB)

Suzuki, S [Japan Energy Economic Research Inst., Tokyo

1975-07-01

In several countries of the world, both financial and human resources are being invested to the development of fast breeder reactors. Quantitative determination of the benefit which will be expected as the reqard to these efforts of research and development - this is the purpose of the present study. It is cost-benefit analysis. The instances of this analysis are given, namely the work in The Institute of Energy Economics in Japan, and also the one by U.S.AEC. The effect of the development of fast breeder reactors is evaluated in this way ; and problems in the analysis method are indicated. These two works in Japan and the U.S. were performed before the so-called oil crisis.

Advanced Interval Management: A Benefit Analysis

Science.gov (United States)

Timer, Sebastian; Peters, Mark

2016-01-01

This document is the final report for the NASA Langley Research Center (LaRC)- sponsored task order 'Possible Benefits for Advanced Interval Management Operations.' Under this research project, Architecture Technology Corporation performed an analysis to determine the maximum potential benefit to be gained if specific Advanced Interval Management (AIM) operations were implemented in the National Airspace System (NAS). The motivation for this research is to guide NASA decision-making on which Interval Management (IM) applications offer the most potential benefit and warrant further research.

Reliability and risk analysis methods research plan

International Nuclear Information System (INIS)

1984-10-01

This document presents a plan for reliability and risk analysis methods research to be performed mainly by the Reactor Risk Branch (RRB), Division of Risk Analysis and Operations (DRAO), Office of Nuclear Regulatory Research. It includes those activities of other DRAO branches which are very closely related to those of the RRB. Related or interfacing programs of other divisions, offices and organizations are merely indicated. The primary use of this document is envisioned as an NRC working document, covering about a 3-year period, to foster better coordination in reliability and risk analysis methods development between the offices of Nuclear Regulatory Research and Nuclear Reactor Regulation. It will also serve as an information source for contractors and others to more clearly understand the objectives, needs, programmatic activities and interfaces together with the overall logical structure of the program

Representative Sampling for reliable data analysis

DEFF Research Database (Denmark)

Petersen, Lars; Esbensen, Kim Harry

2005-01-01

regime in order to secure the necessary reliability of: samples (which must be representative, from the primary sampling onwards), analysis (which will not mean anything outside the miniscule analytical volume without representativity ruling all mass reductions involved, also in the laboratory) and data...

A double-loop adaptive sampling approach for sensitivity-free dynamic reliability analysis

International Nuclear Information System (INIS)

Wang, Zequn; Wang, Pingfeng

2015-01-01

Dynamic reliability measures reliability of an engineered system considering time-variant operation condition and component deterioration. Due to high computational costs, conducting dynamic reliability analysis at an early system design stage remains challenging. This paper presents a confidence-based meta-modeling approach, referred to as double-loop adaptive sampling (DLAS), for efficient sensitivity-free dynamic reliability analysis. The DLAS builds a Gaussian process (GP) model sequentially to approximate extreme system responses over time, so that Monte Carlo simulation (MCS) can be employed directly to estimate dynamic reliability. A generic confidence measure is developed to evaluate the accuracy of dynamic reliability estimation while using the MCS approach based on developed GP models. A double-loop adaptive sampling scheme is developed to efficiently update the GP model in a sequential manner, by considering system input variables and time concurrently in two sampling loops. The model updating process using the developed sampling scheme can be terminated once the user defined confidence target is satisfied. The developed DLAS approach eliminates computationally expensive sensitivity analysis process, thus substantially improves the efficiency of dynamic reliability analysis. Three case studies are used to demonstrate the efficacy of DLAS for dynamic reliability analysis. - Highlights: • Developed a novel adaptive sampling approach for dynamic reliability analysis. • POD Developed a new metric to quantify the accuracy of dynamic reliability estimation. • Developed a new sequential sampling scheme to efficiently update surrogate models. • Three case studies were used to demonstrate the efficacy of the new approach. • Case study results showed substantially enhanced efficiency with high accuracy

Psychometric properties of the Exercise Benefits/Barriers Scale in Mexican elderly women

Directory of Open Access Journals (Sweden)

María Cristina Enríquez-Reyna

Full Text Available ABSTRACT Objective: analyze and assess the psychometric properties of the subscales in the Spanish version of the Exercise Benefits/Barriers Scale in an elderly population in the Northeast of Mexico. Method: methodological study. The sample consisted of 329 elderly associated with one of the five public centers for senior citizens in the metropolitan area of Northeast Mexico. The psychometric properties included the assessment of the Cronbach's alpha coefficient, the Kaiser Meyer Olkin coefficient, the inter-item correlation, exploratory and confirmatory factor analysis. Results: in the principal components analysis, two components were identified based on the 43 items in the scale. The item-total correlation coefficient of the exercise benefits subscale was good. Nevertheless, the coefficient for the exercise barriers subscale revealed inconsistencies. The reliability and validity were acceptable. The confirmatory factor analysis revealed that the elimination of items improved the goodness of fit of the baseline scale, without affecting its validity or reliability. Conclusion: the Exercise Benefits/Barriers subscale presented satisfactory psychometric properties for the Mexican context. A 15-item short version is presented with factorial structure, validity and reliability similar to the complete scale.

Reliability Analysis of Fatigue Fracture of Wind Turbine Drivetrain Components

DEFF Research Database (Denmark)

Berzonskis, Arvydas; Sørensen, John Dalsgaard

2016-01-01

in the volume of the casted ductile iron main shaft, on the reliability of the component. The probabilistic reliability analysis conducted is based on fracture mechanics models. Additionally, the utilization of the probabilistic reliability for operation and maintenance planning and quality control is discussed....

Reliability analysis of cluster-based ad-hoc networks

International Nuclear Information System (INIS)

Cook, Jason L.; Ramirez-Marquez, Jose Emmanuel

2008-01-01

The mobile ad-hoc wireless network (MAWN) is a new and emerging network scheme that is being employed in a variety of applications. The MAWN varies from traditional networks because it is a self-forming and dynamic network. The MAWN is free of infrastructure and, as such, only the mobile nodes comprise the network. Pairs of nodes communicate either directly or through other nodes. To do so, each node acts, in turn, as a source, destination, and relay of messages. The virtue of a MAWN is the flexibility this provides; however, the challenge for reliability analyses is also brought about by this unique feature. The variability and volatility of the MAWN configuration makes typical reliability methods (e.g. reliability block diagram) inappropriate because no single structure or configuration represents all manifestations of a MAWN. For this reason, new methods are being developed to analyze the reliability of this new networking technology. New published methods adapt to this feature by treating the configuration probabilistically or by inclusion of embedded mobility models. This paper joins both methods together and expands upon these works by modifying the problem formulation to address the reliability analysis of a cluster-based MAWN. The cluster-based MAWN is deployed in applications with constraints on networking resources such as bandwidth and energy. This paper presents the problem's formulation, a discussion of applicable reliability metrics for the MAWN, and illustration of a Monte Carlo simulation method through the analysis of several example networks

A Review: Passive System Reliability Analysis – Accomplishments and Unresolved Issues

Energy Technology Data Exchange (ETDEWEB)

Nayak, Arun Kumar, E-mail: arunths@barc.gov.in [Reactor Engineering Division, Reactor Design and Development Group, Bhabha Atomic Research Centre, Mumbai (India); Chandrakar, Amit [Homi Bhabha National Institute, Mumbai (India); Vinod, Gopika [Reactor Safety Division, Reactor Design and Development Group, Bhabha Atomic Research Centre, Mumbai (India)

2014-10-10

Reliability assessment of passive safety systems is one of the important issues, since safety of advanced nuclear reactors rely on several passive features. In this context, a few methodologies such as reliability evaluation of passive safety system (REPAS), reliability methods for passive safety functions (RMPS), and analysis of passive systems reliability (APSRA) have been developed in the past. These methodologies have been used to assess reliability of various passive safety systems. While these methodologies have certain features in common, but they differ in considering certain issues; for example, treatment of model uncertainties, deviation of geometric, and process parameters from their nominal values. This paper presents the state of the art on passive system reliability assessment methodologies, the accomplishments, and remaining issues. In this review, three critical issues pertaining to passive systems performance and reliability have been identified. The first issue is applicability of best estimate codes and model uncertainty. The best estimate codes based phenomenological simulations of natural convection passive systems could have significant amount of uncertainties, these uncertainties must be incorporated in appropriate manner in the performance and reliability analysis of such systems. The second issue is the treatment of dynamic failure characteristics of components of passive systems. REPAS, RMPS, and APSRA methodologies do not consider dynamic failures of components or process, which may have strong influence on the failure of passive systems. The influence of dynamic failure characteristics of components on system failure probability is presented with the help of a dynamic reliability methodology based on Monte Carlo simulation. The analysis of a benchmark problem of Hold-up tank shows the error in failure probability estimation by not considering the dynamism of components. It is thus suggested that dynamic reliability methodologies must be

Analysis and assessment of water treatment plant reliability

Directory of Open Access Journals (Sweden)

Szpak Dawid

2017-03-01

Full Text Available The subject of the publication is the analysis and assessment of the reliability of the surface water treatment plant (WTP. In the study the one parameter method of reliability assessment was used. Based on the flow sheet derived from the water company the reliability scheme of the analysed WTP was prepared. On the basis of the daily WTP work report the availability index Kg for the individual elements included in the WTP, was determined. Then, based on the developed reliability scheme showing the interrelationships between elements, the availability index Kg for the whole WTP was determined. The obtained value of the availability index Kg was compared with the criteria values.

Time-dependent reliability analysis of nuclear reactor operators using probabilistic network models

International Nuclear Information System (INIS)

Oka, Y.; Miyata, K.; Kodaira, H.; Murakami, S.; Kondo, S.; Togo, Y.

1987-01-01

Human factors are very important for the reliability of a nuclear power plant. Human behavior has essentially a time-dependent nature. The details of thinking and decision making processes are important for detailed analysis of human reliability. They have, however, not been well considered by the conventional methods of human reliability analysis. The present paper describes the models for the time-dependent and detailed human reliability analysis. Recovery by an operator is taken into account and two-operators models are also presented

Cost-benefit analysis of FBR program

International Nuclear Information System (INIS)

Suzuki, Shinji

1975-01-01

In several countries of the world, both financial and human resources are being invested to the development of fast breeder reactors. Quantitative determination of the benefit which will be expected as the reqard to these efforts of research and development - this is the purpose of the present study. It is cost-benefit analysis. The instances of this analysis are given, namely the work in The Institute of Energy Economics in Japan, and also the one by U.S.AEC. The effect of the development of fast breeder reactors is evaluated in this way ; and problems in the analysis method are indicated. These two works in Japan and the U.S. were performed before the so-called oil crisis. (Mori, K.)

Procedure for conducting a human-reliability analysis for nuclear power plants. Final report

International Nuclear Information System (INIS)

Bell, B.J.; Swain, A.D.

1983-05-01

This document describes in detail a procedure to be followed in conducting a human reliability analysis as part of a probabilistic risk assessment when such an analysis is performed according to the methods described in NUREG/CR-1278, Handbook for Human Reliability Analysis with Emphasis on Nuclear Power Plant Applications. An overview of the procedure describing the major elements of a human reliability analysis is presented along with a detailed description of each element and an example of an actual analysis. An appendix consists of some sample human reliability analysis problems for further study

Root cause analysis in support of reliability enhancement of engineering components

International Nuclear Information System (INIS)

Kumar, Sachin; Mishra, Vivek; Joshi, N.S.; Varde, P.V.

2014-01-01

Reliability based methods have been widely used for the safety assessment of plant system, structures and components. These methods provide a quantitative estimation of system reliability but do not give insight into the failure mechanism. Understanding the failure mechanism is a must to avoid the recurrence of the events and enhancement of the system reliability. Root cause analysis provides a tool for gaining detailed insights into the causes of failure of component with particular attention to the identification of fault in component design, operation, surveillance, maintenance, training, procedures and policies which must be improved to prevent repetition of incidents. Root cause analysis also helps in developing Probabilistic Safety Analysis models. A probabilistic precursor study provides a complement to the root cause analysis approach in event analysis by focusing on how an event might have developed adversely. This paper discusses the root cause analysis methodologies and their application in the specific case studies for enhancement of system reliability. (author)

DATMAN: A reliability data analysis program using Bayesian updating

International Nuclear Information System (INIS)

Becker, M.; Feltus, M.A.

1996-01-01

Preventive maintenance (PM) techniques focus on the prevention of failures, in particular, system components that are important to plant functions. Reliability-centered maintenance (RCM) improves on the PM techniques by introducing a set of guidelines by which to evaluate the system functions. It also minimizes intrusive maintenance, labor, and equipment downtime without sacrificing system performance when its function is essential for plant safety. Both the PM and RCM approaches require that system reliability data be updated as more component failures and operation time are acquired. Systems reliability and the likelihood of component failures can be calculated by Bayesian statistical methods, which can update these data. The DATMAN computer code has been developed at Penn State to simplify the Bayesian analysis by performing tedious calculations needed for RCM reliability analysis. DATMAN reads data for updating, fits a distribution that best fits the data, and calculates component reliability. DATMAN provides a user-friendly interface menu that allows the user to choose from several common prior and posterior distributions, insert new failure data, and visually select the distribution that matches the data most accurately

The development of a reliable amateur boxing performance analysis template.

Science.gov (United States)

Thomson, Edward; Lamb, Kevin; Nicholas, Ceri

2013-01-01

The aim of this study was to devise a valid performance analysis system for the assessment of the movement characteristics associated with competitive amateur boxing and assess its reliability using analysts of varying experience of the sport and performance analysis. Key performance indicators to characterise the demands of an amateur contest (offensive, defensive and feinting) were developed and notated using a computerised notational analysis system. Data were subjected to intra- and inter-observer reliability assessment using median sign tests and calculating the proportion of agreement within predetermined limits of error. For all performance indicators, intra-observer reliability revealed non-significant differences between observations (P > 0.05) and high agreement was established (80-100%) regardless of whether exact or the reference value of ±1 was applied. Inter-observer reliability was less impressive for both analysts (amateur boxer and experienced analyst), with the proportion of agreement ranging from 33-100%. Nonetheless, there was no systematic bias between observations for any indicator (P > 0.05), and the proportion of agreement within the reference range (±1) was 100%. A reliable performance analysis template has been developed for the assessment of amateur boxing performance and is available for use by researchers, coaches and athletes to classify and quantify the movement characteristics of amateur boxing.

A cost-benefit analysis of The National Map

Science.gov (United States)

Halsing, David L.; Theissen, Kevin; Bernknopf, Richard

2003-01-01

The Geography Discipline of the U.S. Geological Survey (USGS) has conducted this cost-benefit analysis (CBA) of The National Map. This analysis is an evaluation of the proposed Geography Discipline initiative to provide the Nation with a mechanism to access current and consistent digital geospatial data. This CBA is a supporting document to accompany the Exhibit 300 Capital Asset Plan and Business Case of The National Map Reengineering Program. The framework for estimating the benefits is based on expected improvements in processing information to perform any of the possible applications of spatial data. This analysis does not attempt to determine the benefits and costs of performing geospatial-data applications. Rather, it estimates the change in the differences between those benefits and costs with The National Map and the current situation without it. The estimates of total costs and benefits of The National Map were based on the projected implementation time, development and maintenance costs, rates of data inclusion and integration, expected usage levels over time, and a benefits estimation model. The National Map provides data that are current, integrated, consistent, complete, and more accessible in order to decrease the cost of implementing spatial-data applications and (or) improve the outcome of those applications. The efficiency gains in per-application improvements are greater than the cost to develop and maintain The National Map, meaning that the program would bring a positive net benefit to the Nation. The average improvement in the net benefit of performing a spatial data application was multiplied by a simulated number of application implementations across the country. The numbers of users, existing applications, and rates of application implementation increase over time as The National Map is developed and accessed by spatial data users around the country. Results from the 'most likely' estimates of model parameters and data inputs indicate that

Projected Benefits of Federal Energy Efficiency and Renewable Energy Programs. FY 2005 - FY 2050

Energy Technology Data Exchange (ETDEWEB)

None, None

2004-05-01

This report describes a benefits analysis undertaken by EERE to better understand the extent to which the technologies and market improvements funded by its FY 2005 budget request will make energy more affordable, cleaner, and more reliable. It summarizes the results of the analysis, which focused on economic, environmental, and security benefits related to energy. The report identifies specific measures or indicators of estimated benefits for FY 2005.

Reliability Worth Analysis of Distribution Systems Using Cascade Correlation Neural Networks

DEFF Research Database (Denmark)

Heidari, Alireza; Agelidis, Vassilios; Pou, Josep

2018-01-01

Reliability worth analysis is of great importance in the area of distribution network planning and operation. The reliability worth's precision can be affected greatly by the customer interruption cost model used. The choice of the cost models can change system and load point reliability indices....... In this study, a cascade correlation neural network is adopted to further develop two cost models comprising a probabilistic distribution model and an average or aggregate model. A contingency-based analytical technique is adopted to conduct the reliability worth analysis. Furthermore, the possible effects...

Space Mission Human Reliability Analysis (HRA) Project

Data.gov (United States)

National Aeronautics and Space Administration — The purpose of this project is to extend current ground-based Human Reliability Analysis (HRA) techniques to a long-duration, space-based tool to more effectively...

How (not) to Lie with Benefit-Cost Analysis

OpenAIRE

Scott Farrow

2013-01-01

Benefit-cost analysis is seen by some as a controversial activity in which the analyst can significantly bias the results. This note highlights some of the ways that analysts can "lie" in a benefit-cost analysis but more importantly, provides guidance on how not to lie and how to better inform public decisionmakers.

A new approach for reliability analysis with time-variant performance characteristics

International Nuclear Information System (INIS)

Wang, Zequn; Wang, Pingfeng

2013-01-01

Reliability represents safety level in industry practice and may variant due to time-variant operation condition and components deterioration throughout a product life-cycle. Thus, the capability to perform time-variant reliability analysis is of vital importance in practical engineering applications. This paper presents a new approach, referred to as nested extreme response surface (NERS), that can efficiently tackle time dependency issue in time-variant reliability analysis and enable to solve such problem by easily integrating with advanced time-independent tools. The key of the NERS approach is to build a nested response surface of time corresponding to the extreme value of the limit state function by employing Kriging model. To obtain the data for the Kriging model, the efficient global optimization technique is integrated with the NERS to extract the extreme time responses of the limit state function for any given system input. An adaptive response prediction and model maturation mechanism is developed based on mean square error (MSE) to concurrently improve the accuracy and computational efficiency of the proposed approach. With the nested response surface of time, the time-variant reliability analysis can be converted into the time-independent reliability analysis and existing advanced reliability analysis methods can be used. Three case studies are used to demonstrate the efficiency and accuracy of NERS approach

Reliable design of electronic equipment an engineering guide

CERN Document Server

Natarajan, Dhanasekharan

2014-01-01

This book explains reliability techniques with examples from electronics design for the benefit of engineers. It presents the application of de-rating, FMEA, overstress analyses and reliability improvement tests for designing reliable electronic equipment. Adequate information is provided for designing computerized reliability database system to support the application of the techniques by designers. Pedantic terms and the associated mathematics of reliability engineering discipline are excluded for the benefit of comprehensiveness and practical applications. This book offers excellent support

Methodology for reliability allocation based on fault tree analysis and dualistic contrast

Institute of Scientific and Technical Information of China (English)

TONG Lili; CAO Xuewu

2008-01-01

Reliability allocation is a difficult multi-objective optimization problem.This paper presents a methodology for reliability allocation that can be applied to determine the reliability characteristics of reactor systems or subsystems.The dualistic contrast,known as one of the most powerful tools for optimization problems,is applied to the reliability allocation model of a typical system in this article.And the fault tree analysis,deemed to be one of the effective methods of reliability analysis,is also adopted.Thus a failure rate allocation model based on the fault tree analysis and dualistic contrast is achieved.An application on the emergency diesel generator in the nuclear power plant is given to illustrate the proposed method.

Reliability analysis of protection system of advanced pressurized water reactor - APR 1400

International Nuclear Information System (INIS)

Varde, P. V.; Choi, J. G.; Lee, D. Y.; Han, J. B.

2003-04-01

Reliability analysis was carried out for the protection system of the Korean Advanced Pressurized Water Reactor - APR 1400. The main focus of this study was the reliability analysis of digital protection system, however, towards giving an integrated statement of complete protection reliability an attempt has been made to include the shutdown devices and other related aspects based on the information available to date. The sensitivity analysis has been carried out for the critical components / functions in the system. Other aspects like importance analysis and human error reliability for the critical human actions form part of this work. The framework provided by this study and the results obtained shows that this analysis has potential to be utilized as part of risk informed approach for future design / regulatory applications

Lean VOC-Air Mixtures Catalytic Treatment: Cost-Benefit Analysis of Competing Technologies

Directory of Open Access Journals (Sweden)

Gabriele Baldissone

2017-06-01

Full Text Available Various processing routes are available for the treatment of lean VOC-air mixtures, and a cost-benefit analysis is the tool we propose to identify the most suitable technology. Two systems have been compared in this paper, namely a “traditional” plant, with a catalytic fixed-bed reactor with a heat exchanger for heat recovery purposes, and a “non-traditional” plant, with a catalytic reverse-flow reactor, where regenerative heat recovery may be achieved thanks to the periodical reversal of the flow direction. To be useful for decisions-making, the cost-benefit analysis must be coupled to the reliability, or availability, analysis of the plant. Integrated Dynamic Decision Analysis is used for this purpose as it allows obtaining the full set of possible sequences of events that could result in plant unavailability, and, for each of them, the probability of occurrence is calculated. Benefits are thus expressed in terms of out-of-services times, that have to be minimized, while the costs are expressed in terms of extra-cost for maintenance activities and recovery actions. These variable costs must be considered together with the capital (fixed cost required for building the plant. Results evidenced the pros and cons of the two plants. The “traditional” plant ensures a higher continuity of services, but also higher operational costs. The reverse-flow reactor-based plant exhibits lower operational costs, but a higher number of protection levels are needed to obtain a similar level of out-of-service. The quantification of risks and benefits allows the stakeholders to deal with a complete picture of the behavior of the plants, fostering a more effective decision-making process. With reference to the case under study and the relevant operational conditions, the regenerative system was demonstrated to be more suitable to treat lean mixtures: in terms of time losses following potential failures the two technologies are comparable (Fixed bed

Benefit transfers and valuation of environmental improvements

International Nuclear Information System (INIS)

Krupnick, A.J.

1993-01-01

Growing demand for analyses of the benefits of environmental improvements (or the costs of environmental damages) has increased interest in using estimates of such benefits in one setting to calculate benefits in another setting. At present, some types of these benefits (or costs) - which can be categorized as effects on health, output, economics assets, and environmental assets - are more amenable to such benefit transfers than others. Original studies that value health effects, for example, do not always lend themselves to benefit transfers. Most of the studies that value mortality risk address the risk of accidental death, which is an inappropriate context for valuing deaths from environmental causes. One way to make benefit transfers more feasible and reliable is to design original research with the purpose of obtaining results to be used in benefit transfers. As an example, one of the most successful benefit-transfer exercises to date involves the US Environmental Protection Agency's cost-benefit analysis of regulations for phasing down the lead content of gasoline. In this analysis, the agency used existing benefit studies to estimate the values of reducing premature deaths an of avoiding acute health effects by decreasing individuals exposure to lead in gasoline. On the basis of these and other estimates, EPA argued that the phasedown made economic sense

Reliability analysis of diverse safety logic systems of fast breeder reactor

International Nuclear Information System (INIS)

Ravi Kumar, Bh.; Apte, P.R.; Srivani, L.; Ilango Sambasivan, S.; Swaminathan, P.

2006-01-01

Safety Logic for Fast Breeder Reactor (FBR) is designed to initiate safety action against Design Basis Events. Based on the outputs of various processing circuits, Safety logic system drives the control rods of the shutdown system. So, Safety Logic system is classified as safety critical system. Therefore, reliability analysis has to be performed. This paper discusses the Reliability analysis of Diverse Safety logic systems of FBRs. For this literature survey on safety critical systems, system reliability approach and standards to be followed like IEC-61508 are discussed in detail. For Programmable Logic device based systems, Hardware Description Languages (HDL) are used. So this paper also discusses the Verification and Validation for HDLs. Finally a case study for the Reliability analysis of Safety logic is discussed. (author)

Reliability analysis of safety systems of nuclear power plant and utility experience with reliability safeguarding of systems during specified normal operation

International Nuclear Information System (INIS)

Balfanz, H.P.

1989-01-01

The paper gives an outline of the methods applied for reliability analysis of safety systems in nuclear power plant. The main tasks are to check the system design for detection of weak points, and to find possibilities of optimizing the strategies for inspection, inspection intervals, maintenance periods. Reliability safeguarding measures include the determination and verification of the broundary conditions of the analysis with regard to the reliability parameters and maintenance parameters used in the analysis, and the analysis of data feedback reflecting the plant response during operation. (orig.) [de

Environmental cost/benefit analysis for fusion power plants

International Nuclear Information System (INIS)

Young, J.R.

1976-11-01

This document presents a cost/benefit analysis of use of fusion power plants early in the 21st century. The first section describes the general formulation of the analysis. Included are the selection of the alternatives to the fusion reactor, selection of the power system cases to be compared, and a general comparison of the environmental effects of the selected alternatives. The second section compares the cumulative environmental effects from 2010 to 2040 for the primary cases of the power system with and without fusion reactors. The third section briefly illustrates the potential economic benefits if fusion reactors produce electricity at a lower unit cost than LMFBRs can. The fourth section summarizes the cost/benefit analysis

Transmission cost allocation based on power flow tracing considering reliability benefit

International Nuclear Information System (INIS)

Leepreechanon, N.; Singharerg, S.; Padungwech, W.; Nakawiro, W.; Eua-Arporn, B.; David, A.K.

2007-01-01

Power transmission networks must be able to accommodate the continuously growing demand for reliable and economical electricity. This paper presented a method to allocate transmission use and reliability cost to both generators and end-consumers. Although transmission cost allocation methods change depending on the local context of the electric power industry, there is a common principle that transmission line capacity should be properly allocated to accommodate actual power delivery with an adequate reliability margin. The method proposed in this paper allocates transmission embedded cost to both generators and loads in an equitable manner, incorporating probability indices to allocate transmission reliability margin among users in both supply and demand sides. The application of the proposed method was illustrated using Bialek's tracing method on a multiple-circuit, six-bus transmission system. Probabilistic indices known as the transmission internal reliability margin (TIRM) and transmission external reliability margin (TERM) decomposed from the transmission reliability margin (TRM) were introduced, making true cost of using overall transmission facilities. 6 refs., 11 tabs., 5 figs

Reliability-Based Robustness Analysis for a Croatian Sports Hall

DEFF Research Database (Denmark)

Čizmar, Dean; Kirkegaard, Poul Henning; Sørensen, John Dalsgaard

2011-01-01

This paper presents a probabilistic approach for structural robustness assessment for a timber structure built a few years ago. The robustness analysis is based on a structural reliability based framework for robustness and a simplified mechanical system modelling of a timber truss system....... A complex timber structure with a large number of failure modes is modelled with only a few dominant failure modes. First, a component based robustness analysis is performed based on the reliability indices of the remaining elements after the removal of selected critical elements. The robustness...... is expressed and evaluated by a robustness index. Next, the robustness is assessed using system reliability indices where the probabilistic failure model is modelled by a series system of parallel systems....

Reliability analysis of prestressed concrete containment structures

International Nuclear Information System (INIS)

Jiang, J.; Zhao, Y.; Sun, J.

1993-01-01

The reliability analysis of prestressed concrete containment structures subjected to combinations of static and dynamic loads with consideration of uncertainties of structural and load parameters is presented. Limit state probabilities for given parameters are calculated using the procedure developed at BNL, while that with consideration of parameter uncertainties are calculated by a fast integration for time variant structural reliability. The limit state surface of the prestressed concrete containment is constructed directly incorporating the prestress. The sensitivities of the Choleskey decomposition matrix and the natural vibration character are calculated by simplified procedures. (author)

Modeling and Analysis of Component Faults and Reliability

DEFF Research Database (Denmark)

Le Guilly, Thibaut; Olsen, Petur; Ravn, Anders Peter

2016-01-01

This chapter presents a process to design and validate models of reactive systems in the form of communicating timed automata. The models are extended with faults associated with probabilities of occurrence. This enables a fault tree analysis of the system using minimal cut sets that are automati......This chapter presents a process to design and validate models of reactive systems in the form of communicating timed automata. The models are extended with faults associated with probabilities of occurrence. This enables a fault tree analysis of the system using minimal cut sets...... that are automatically generated. The stochastic information on the faults is used to estimate the reliability of the fault affected system. The reliability is given with respect to properties of the system state space. We illustrate the process on a concrete example using the Uppaal model checker for validating...... the ideal system model and the fault modeling. Then the statistical version of the tool, UppaalSMC, is used to find reliability estimates....

Cost-Benefit Analysis and the Democratic Ideal

OpenAIRE

Karine Nyborg; Inger Spangen

1997-01-01

In traditional cost-benefit analyses of public projects, every citizen’s willingness to pay for a project is given an equal weight. This is sometimes taken to imply that cost-benefit analysis is a democratic method for making public decisions, as opposed to, for example, political processes involving log-rolling and lobbying from interest groups. Politicians are frequently criticized for not putting enough emphasis on the cost-benefit analyses when making decisions. In this paper we discuss t...

Reliability analysis of wind embedded power generation system for ...

African Journals Online (AJOL)

This paper presents a method for Reliability Analysis of wind energy embedded in power generation system for Indian scenario. This is done by evaluating the reliability index, loss of load expectation, for the power generation system with and without integration of wind energy sources in the overall electric power system.

Reliability analysis for thermal cutting method based non-explosive separation device

International Nuclear Information System (INIS)

Choi, Jun Woo; Hwang, Kuk Ha; Kim, Byung Kyu

2016-01-01

In order to increase the reliability of a separation device for a small satellite, a new non-explosive separation device is invented. This device is activated using a thermal cutting method with a Ni-Cr wire. A reliability analysis is carried out for the proposed non-explosive separation device by applying the Fault tree analysis (FTA) method. In the FTA results for the separation device, only ten single-point failure modes are found. The reliability modeling and analysis for the device are performed considering failure of the power supply, the Ni-Cr wire burns failure and unwinds, the holder separation failure, the balls separation failure, and the pin release failure. Ultimately, the reliability of the proposed device is calculated as 0.999989 with five Ni-Cr wire coils

Reliability analysis for thermal cutting method based non-explosive separation device

Energy Technology Data Exchange (ETDEWEB)

Choi, Jun Woo; Hwang, Kuk Ha; Kim, Byung Kyu [Korea Aerospace University, Goyang (Korea, Republic of)

2016-12-15

In order to increase the reliability of a separation device for a small satellite, a new non-explosive separation device is invented. This device is activated using a thermal cutting method with a Ni-Cr wire. A reliability analysis is carried out for the proposed non-explosive separation device by applying the Fault tree analysis (FTA) method. In the FTA results for the separation device, only ten single-point failure modes are found. The reliability modeling and analysis for the device are performed considering failure of the power supply, the Ni-Cr wire burns failure and unwinds, the holder separation failure, the balls separation failure, and the pin release failure. Ultimately, the reliability of the proposed device is calculated as 0.999989 with five Ni-Cr wire coils.

Cost benefit analysis cost effectiveness analysis

International Nuclear Information System (INIS)

Lombard, J.

1986-09-01

The comparison of various protection options in order to determine which is the best compromise between cost of protection and residual risk is the purpose of the ALARA procedure. The use of decision-aiding techniques is valuable as an aid to selection procedures. The purpose of this study is to introduce two rather simple and well known decision aiding techniques: the cost-effectiveness analysis and the cost-benefit analysis. These two techniques are relevant for the great part of ALARA decisions which need the use of a quantitative technique. The study is based on an hypothetical case of 10 protection options. Four methods are applied to the data

Benefit-Risk Analysis for Decision-Making: An Approach.

Science.gov (United States)

Raju, G K; Gurumurthi, K; Domike, R

2016-12-01

The analysis of benefit and risk is an important aspect of decision-making throughout the drug lifecycle. In this work, the use of a benefit-risk analysis approach to support decision-making was explored. The proposed approach builds on the qualitative US Food and Drug Administration (FDA) approach to include a more explicit analysis based on international standards and guidance that enables aggregation and comparison of benefit and risk on a common basis and a lifecycle focus. The approach is demonstrated on six decisions over the lifecycle (e.g., accelerated approval, withdrawal, and traditional approval) using two case studies: natalizumab for multiple sclerosis (MS) and bedaquiline for multidrug-resistant tuberculosis (MDR-TB). © 2016 American Society for Clinical Pharmacology and Therapeutics.

Statistical models and methods for reliability and survival analysis

CERN Document Server

Couallier, Vincent; Huber-Carol, Catherine; Mesbah, Mounir; Huber -Carol, Catherine; Limnios, Nikolaos; Gerville-Reache, Leo

2013-01-01

Statistical Models and Methods for Reliability and Survival Analysis brings together contributions by specialists in statistical theory as they discuss their applications providing up-to-date developments in methods used in survival analysis, statistical goodness of fit, stochastic processes for system reliability, amongst others. Many of these are related to the work of Professor M. Nikulin in statistics over the past 30 years. The authors gather together various contributions with a broad array of techniques and results, divided into three parts - Statistical Models and Methods, Statistical

Comparison of methods for dependency determination between human failure events within human reliability analysis

International Nuclear Information System (INIS)

Cepis, M.

2007-01-01

The Human Reliability Analysis (HRA) is a highly subjective evaluation of human performance, which is an input for probabilistic safety assessment, which deals with many parameters of high uncertainty. The objective of this paper is to show that subjectivism can have a large impact on human reliability results and consequently on probabilistic safety assessment results and applications. The objective is to identify the key features, which may decrease of subjectivity of human reliability analysis. Human reliability methods are compared with focus on dependency comparison between Institute Jozef Stefan - Human Reliability Analysis (IJS-HRA) and Standardized Plant Analysis Risk Human Reliability Analysis (SPAR-H). Results show large differences in the calculated human error probabilities for the same events within the same probabilistic safety assessment, which are the consequence of subjectivity. The subjectivity can be reduced by development of more detailed guidelines for human reliability analysis with many practical examples for all steps of the process of evaluation of human performance. (author)

Comparison of Methods for Dependency Determination between Human Failure Events within Human Reliability Analysis

International Nuclear Information System (INIS)

Cepin, M.

2008-01-01

The human reliability analysis (HRA) is a highly subjective evaluation of human performance, which is an input for probabilistic safety assessment, which deals with many parameters of high uncertainty. The objective of this paper is to show that subjectivism can have a large impact on human reliability results and consequently on probabilistic safety assessment results and applications. The objective is to identify the key features, which may decrease subjectivity of human reliability analysis. Human reliability methods are compared with focus on dependency comparison between Institute Jozef Stefan human reliability analysis (IJS-HRA) and standardized plant analysis risk human reliability analysis (SPAR-H). Results show large differences in the calculated human error probabilities for the same events within the same probabilistic safety assessment, which are the consequence of subjectivity. The subjectivity can be reduced by development of more detailed guidelines for human reliability analysis with many practical examples for all steps of the process of evaluation of human performance

Validity and reliability of acoustic analysis of respiratory sounds in infants

Science.gov (United States)

Elphick, H; Lancaster, G; Solis, A; Majumdar, A; Gupta, R; Smyth, R

2004-01-01

Objective: To investigate the validity and reliability of computerised acoustic analysis in the detection of abnormal respiratory noises in infants. Methods: Blinded, prospective comparison of acoustic analysis with stethoscope examination. Validity and reliability of acoustic analysis were assessed by calculating the degree of observer agreement using the κ statistic with 95% confidence intervals (CI). Results: 102 infants under 18 months were recruited. Convergent validity for agreement between stethoscope examination and acoustic analysis was poor for wheeze (κ = 0.07 (95% CI, –0.13 to 0.26)) and rattles (κ = 0.11 (–0.05 to 0.27)) and fair for crackles (κ = 0.36 (0.18 to 0.54)). Both the stethoscope and acoustic analysis distinguished well between sounds (discriminant validity). Agreement between observers for the presence of wheeze was poor for both stethoscope examination and acoustic analysis. Agreement for rattles was moderate for the stethoscope but poor for acoustic analysis. Agreement for crackles was moderate using both techniques. Within-observer reliability for all sounds using acoustic analysis was moderate to good. Conclusions: The stethoscope is unreliable for assessing respiratory sounds in infants. This has important implications for its use as a diagnostic tool for lung disorders in infants, and confirms that it cannot be used as a gold standard. Because of the unreliability of the stethoscope, the validity of acoustic analysis could not be demonstrated, although it could discriminate between sounds well and showed good within-observer reliability. For acoustic analysis, targeted training and the development of computerised pattern recognition systems may improve reliability so that it can be used in clinical practice. PMID:15499065

Human reliability analysis of performing tasks in plants based on fuzzy integral

International Nuclear Information System (INIS)

Washio, Takashi; Kitamura, Yutaka; Takahashi, Hideaki

1991-01-01

The effective improvement of the human working conditions in nuclear power plants might be a solution for the enhancement of the operation safety. The human reliability analysis (HRA) gives a methodological basis of the improvement based on the evaluation of human reliability under various working conditions. This study investigates some difficulties of the human reliability analysis using conventional linear models and recent fuzzy integral models, and provides some solutions to the difficulties. The following practical features of the provided methods are confirmed in comparison with the conventional methods: (1) Applicability to various types of tasks (2) Capability of evaluating complicated dependencies among working condition factors (3) A priori human reliability evaluation based on a systematic task analysis of human action processes (4) A conversion scheme to probability from indices representing human reliability. (author)

DER Benefits Analysis Studies: Final Report

Energy Technology Data Exchange (ETDEWEB)

Iannucci, J. J.; Cibulka, L.; Eyer, J. M.; Pupp, R. L.

2003-09-01

The electric power industry in the United States is undergoing dramatic change. Once totally controlled by utilities that had monopolistic holds on the supply, transmission and distribution of electricity in their service areas, the electric power system is being deregulated, introducing competition among electricity providers who can distinguish themselves by price, services and other factors. The new electric power system will feature advanced technologies and services that can be used on-site or located in close proximity to the load, instead of depending solely upon large, central station generation and transmission. Using a variety of advanced modular generating technologies (including small-scale renewables), distributed energy resource (DER) plants supply base-load power, peaking power, backup power, remote power and/or heating and cooling, and in some cases supply higher and more reliable quality power. Currently, DER represent a minor part of the electric supply system. If the potential of DER is to be realized in the new electric power market, a full understanding of the value and benefits these technologies provide to the electric system is necessary. This report includes 30 key quantitative studies reporting on the values and benefits of distributed energy generation technologies (including renewables) in various applications, as well as a matrix that permits key comparisons.

Reliability Analysis and Optimal Design of Monolithic Vertical Wall Breakwaters

DEFF Research Database (Denmark)

Sørensen, John Dalsgaard; Burcharth, Hans F.; Christiani, E.

1994-01-01

Reliability analysis and reliability-based design of monolithic vertical wall breakwaters are considered. Probabilistic models of the most important failure modes, sliding failure, failure of the foundation and overturning failure are described . Relevant design variables are identified...

Reliability importance analysis of Markovian systems at steady state using perturbation analysis

Energy Technology Data Exchange (ETDEWEB)

Phuc Do Van [Institut Charles Delaunay - FRE CNRS 2848, Systems Modeling and Dependability Group, Universite de technologie de Troyes, 12, rue Marie Curie, BP 2060-10010 Troyes cedex (France); Barros, Anne [Institut Charles Delaunay - FRE CNRS 2848, Systems Modeling and Dependability Group, Universite de technologie de Troyes, 12, rue Marie Curie, BP 2060-10010 Troyes cedex (France)], E-mail: anne.barros@utt.fr; Berenguer, Christophe [Institut Charles Delaunay - FRE CNRS 2848, Systems Modeling and Dependability Group, Universite de technologie de Troyes, 12, rue Marie Curie, BP 2060-10010 Troyes cedex (France)

2008-11-15

Sensitivity analysis has been primarily defined for static systems, i.e. systems described by combinatorial reliability models (fault or event trees). Several structural and probabilistic measures have been proposed to assess the components importance. For dynamic systems including inter-component and functional dependencies (cold spare, shared load, shared resources, etc.), and described by Markov models or, more generally, by discrete events dynamic systems models, the problem of sensitivity analysis remains widely open. In this paper, the perturbation method is used to estimate an importance factor, called multi-directional sensitivity measure, in the framework of Markovian systems. Some numerical examples are introduced to show why this method offers a promising tool for steady-state sensitivity analysis of Markov processes in reliability studies.

Reliability importance analysis of Markovian systems at steady state using perturbation analysis

International Nuclear Information System (INIS)

Phuc Do Van; Barros, Anne; Berenguer, Christophe

2008-01-01

Sensitivity analysis has been primarily defined for static systems, i.e. systems described by combinatorial reliability models (fault or event trees). Several structural and probabilistic measures have been proposed to assess the components importance. For dynamic systems including inter-component and functional dependencies (cold spare, shared load, shared resources, etc.), and described by Markov models or, more generally, by discrete events dynamic systems models, the problem of sensitivity analysis remains widely open. In this paper, the perturbation method is used to estimate an importance factor, called multi-directional sensitivity measure, in the framework of Markovian systems. Some numerical examples are introduced to show why this method offers a promising tool for steady-state sensitivity analysis of Markov processes in reliability studies

A study of operational and testing reliability in software reliability analysis

International Nuclear Information System (INIS)

Yang, B.; Xie, M.

2000-01-01

Software reliability is an important aspect of any complex equipment today. Software reliability is usually estimated based on reliability models such as nonhomogeneous Poisson process (NHPP) models. Software systems are improving in testing phase, while it normally does not change in operational phase. Depending on whether the reliability is to be predicted for testing phase or operation phase, different measure should be used. In this paper, two different reliability concepts, namely, the operational reliability and the testing reliability, are clarified and studied in detail. These concepts have been mixed up or even misused in some existing literature. Using different reliability concept will lead to different reliability values obtained and it will further lead to different reliability-based decisions made. The difference of the estimated reliabilities is studied and the effect on the optimal release time is investigated

Integrated Reliability Estimation of a Nuclear Maintenance Robot including a Software

Energy Technology Data Exchange (ETDEWEB)

Eom, Heung Seop; Kim, Jae Hee; Jeong, Kyung Min [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2011-10-15

Conventional reliability estimation techniques such as Fault Tree Analysis (FTA), Reliability Block Diagram (RBD), Markov Model, and Event Tree Analysis (ETA) have been used widely and approved in some industries. Then there are some limitations when we use them for a complicate robot systems including software such as intelligent reactor inspection robots. Therefore an expert's judgment plays an important role in estimating the reliability of a complicate system in practice, because experts can deal with diverse evidence related to the reliability and then perform an inference based on them. The proposed method in this paper combines qualitative and quantitative evidences and performs an inference like experts. Furthermore, it does the work in a formal and in a quantitative way unlike human experts, by the benefits of Bayesian Nets (BNs)

Beyond reliability, multi-state failure analysis of satellite subsystems: A statistical approach

International Nuclear Information System (INIS)

Castet, Jean-Francois; Saleh, Joseph H.

2010-01-01

Reliability is widely recognized as a critical design attribute for space systems. In recent articles, we conducted nonparametric analyses and Weibull fits of satellite and satellite subsystems reliability for 1584 Earth-orbiting satellites launched between January 1990 and October 2008. In this paper, we extend our investigation of failures of satellites and satellite subsystems beyond the binary concept of reliability to the analysis of their anomalies and multi-state failures. In reliability analysis, the system or subsystem under study is considered to be either in an operational or failed state; multi-state failure analysis introduces 'degraded states' or partial failures, and thus provides more insights through finer resolution into the degradation behavior of an item and its progression towards complete failure. The database used for the statistical analysis in the present work identifies five states for each satellite subsystem: three degraded states, one fully operational state, and one failed state (complete failure). Because our dataset is right-censored, we calculate the nonparametric probability of transitioning between states for each satellite subsystem with the Kaplan-Meier estimator, and we derive confidence intervals for each probability of transitioning between states. We then conduct parametric Weibull fits of these probabilities using the Maximum Likelihood Estimation (MLE) approach. After validating the results, we compare the reliability versus multi-state failure analyses of three satellite subsystems: the thruster/fuel; the telemetry, tracking, and control (TTC); and the gyro/sensor/reaction wheel subsystems. The results are particularly revealing of the insights that can be gleaned from multi-state failure analysis and the deficiencies, or blind spots, of the traditional reliability analysis. In addition to the specific results provided here, which should prove particularly useful to the space industry, this work highlights the importance

Using a Hybrid Cost-FMEA Analysis for Wind Turbine Reliability Analysis

Directory of Open Access Journals (Sweden)

Nacef Tazi

2017-02-01

Full Text Available Failure mode and effects analysis (FMEA has been proven to be an effective methodology to improve system design reliability. However, the standard approach reveals some weaknesses when applied to wind turbine systems. The conventional criticality assessment method has been criticized as having many limitations such as the weighting of severity and detection factors. In this paper, we aim to overcome these drawbacks and develop a hybrid cost-FMEA by integrating cost factors to assess the criticality, these costs vary from replacement costs to expected failure costs. Then, a quantitative comparative study is carried out to point out average failure rate, main cause of failure, expected failure costs and failure detection techniques. A special reliability analysis of gearbox and rotor-blades are presented.

Reliability and statistical power analysis of cortical and subcortical FreeSurfer metrics in a large sample of healthy elderly.

Science.gov (United States)

Liem, Franziskus; Mérillat, Susan; Bezzola, Ladina; Hirsiger, Sarah; Philipp, Michel; Madhyastha, Tara; Jäncke, Lutz

2015-03-01

FreeSurfer is a tool to quantify cortical and subcortical brain anatomy automatically and noninvasively. Previous studies have reported reliability and statistical power analyses in relatively small samples or only selected one aspect of brain anatomy. Here, we investigated reliability and statistical power of cortical thickness, surface area, volume, and the volume of subcortical structures in a large sample (N=189) of healthy elderly subjects (64+ years). Reliability (intraclass correlation coefficient) of cortical and subcortical parameters is generally high (cortical: ICCs>0.87, subcortical: ICCs>0.95). Surface-based smoothing increases reliability of cortical thickness maps, while it decreases reliability of cortical surface area and volume. Nevertheless, statistical power of all measures benefits from smoothing. When aiming to detect a 10% difference between groups, the number of subjects required to test effects with sufficient power over the entire cortex varies between cortical measures (cortical thickness: N=39, surface area: N=21, volume: N=81; 10mm smoothing, power=0.8, α=0.05). For subcortical regions this number is between 16 and 76 subjects, depending on the region. We also demonstrate the advantage of within-subject designs over between-subject designs. Furthermore, we publicly provide a tool that allows researchers to perform a priori power analysis and sensitivity analysis to help evaluate previously published studies and to design future studies with sufficient statistical power. Copyright © 2014 Elsevier Inc. All rights reserved.

Reliability analysis of the automatic control and power supply of reactor equipment

International Nuclear Information System (INIS)

Monori, Pal; Nagy, J.A.; Meszaros, Zoltan; Konkoly, Laszlo; Szabo, Antal; Nagy, Laszlo

1988-01-01

Based on reliability analysis the shortcomings of nuclear facilities are discovered. Fault tree types constructed for the technology of automatic control and for power supply serve as input data of the ORCHARD 2 computer code. In order to charaterize the reliability of the system, availability, failure rates and time intervals between failures are calculated. The results of the reliability analysis of the feedwater system of the Paks Nuclear Power Plant showed that the system consisted of elements of similar reliabilities. (V.N.) 8 figs.; 3 tabs

An evaluation of the Browns Ferry Nuclear Plant preventive maintenance program based on reliability centered maintenance analysis

International Nuclear Information System (INIS)

McCullough, C.L.; McCullough, C.A.

1989-01-01

Reliability centered maintenance (RCM) techniques were used to support a preventative maintenance (PM) upgrade program (PMUP) performed at TVA Browns Ferry Nuclear Plant (BFNP). The purpose of the RCM analysis was to identify critical equipment based on risk and economic importance and to evaluate the PM activities applicable to that equipment. The analysis may be conveniently divided into three steps, which will be outlined in the Approach section of this paper. The net benefit of the RCM approach was a prioritization of the focus of the PM upgrade program so that plant components receive attention proportional to their importance, and assurance that PM activities properly address the most likely component failure causes

Probabilistic safety analysis and human reliability analysis. Proceedings. Working material

International Nuclear Information System (INIS)

1996-01-01

An international meeting on Probabilistic Safety Assessment (PSA) and Human Reliability Analysis (HRA) was jointly organized by Electricite de France - Research and Development (EDF DER) and SRI International in co-ordination with the International Atomic Energy Agency. The meeting was held in Paris 21-23 November 1994. A group of international and French specialists in PSA and HRA participated at the meeting and discussed the state of the art and current trends in the following six topics: PSA Methodology; PSA Applications; From PSA to Dependability; Incident Analysis; Safety Indicators; Human Reliability. For each topic a background paper was prepared by EDF/DER and reviewed by the international group of specialists who attended the meeting. The results of this meeting provide a comprehensive overview of the most important questions related to the readiness of PSA for specific uses and areas where further research and development is required. Refs, figs, tabs

Probabilistic safety analysis and human reliability analysis. Proceedings. Working material

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-12-31

An international meeting on Probabilistic Safety Assessment (PSA) and Human Reliability Analysis (HRA) was jointly organized by Electricite de France - Research and Development (EDF DER) and SRI International in co-ordination with the International Atomic Energy Agency. The meeting was held in Paris 21-23 November 1994. A group of international and French specialists in PSA and HRA participated at the meeting and discussed the state of the art and current trends in the following six topics: PSA Methodology; PSA Applications; From PSA to Dependability; Incident Analysis; Safety Indicators; Human Reliability. For each topic a background paper was prepared by EDF/DER and reviewed by the international group of specialists who attended the meeting. The results of this meeting provide a comprehensive overview of the most important questions related to the readiness of PSA for specific uses and areas where further research and development is required. Refs, figs, tabs.

BENEFIT-COST ANALYSIS IN U.S. ENVIRONMENTAL REGULATORY DECISIONS

OpenAIRE

Easter, K. William; Archibald, Sandra O.

1998-01-01

As the number and cost of environmental regulations have increased over the last thirty years, the regulated community, taxpayers, and policy makers have begun to demand that the benefits of regulations justify their costs. The use of benefit-cost analysis as an integral part of developing new regulations is increasing and the demands and expectations being placed on the method have expanded. Although benefit-cost analysis is expected to play an even greater role in environmental decision mak...

Reliability Analysis of Wireless Sensor Networks Using Markovian Model

Directory of Open Access Journals (Sweden)

Jin Zhu

2012-01-01

Full Text Available This paper investigates reliability analysis of wireless sensor networks whose topology is switching among possible connections which are governed by a Markovian chain. We give the quantized relations between network topology, data acquisition rate, nodes' calculation ability, and network reliability. By applying Lyapunov method, sufficient conditions of network reliability are proposed for such topology switching networks with constant or varying data acquisition rate. With the conditions satisfied, the quantity of data transported over wireless network node will not exceed node capacity such that reliability is ensured. Our theoretical work helps to provide a deeper understanding of real-world wireless sensor networks, which may find its application in the fields of network design and topology control.

Analysis of sodium valve reliability data at CREDO

International Nuclear Information System (INIS)

Bott, T.F.; Haas, P.M.

1979-01-01

The Centralized Reliability Data Organization (CREDO) has been established at Oak Ridge National Laboratory (ORNL) by the Department of Energy to provide a centralized source of data for reliability/maintainabilty analysis of advanced reactor systems. The current schedule calls for develoment of the data system at a moderate pace, with the first major distribution of data in late FY-1980. Continuous long-term collection of engineering, operating, and event data has been initiated at EBR-II and FFTF

Interrater reliability of videotaped observational gait-analysis assessments.

Science.gov (United States)

Eastlack, M E; Arvidson, J; Snyder-Mackler, L; Danoff, J V; McGarvey, C L

1991-06-01

The purpose of this study was to determine the interrater reliability of videotaped observational gait-analysis (VOGA) assessments. Fifty-four licensed physical therapists with varying amounts of clinical experience served as raters. Three patients with rheumatoid arthritis who demonstrated an abnormal gait pattern served as subjects for the videotape. The raters analyzed each patient's most severely involved knee during the four subphases of stance for the kinematic variables of knee flexion and genu valgum. Raters were asked to determine whether these variables were inadequate, normal, or excessive. The temporospatial variables analyzed throughout the entire gait cycle were cadence, step length, stride length, stance time, and step width. Generalized kappa coefficients ranged from .11 to .52. Intraclass correlation coefficients (2,1) and (3,1) were slightly higher. Our results indicate that physical therapists' VOGA assessments are only slightly to moderately reliable and that improved interrater reliability of the assessments of physical therapists utilizing this technique is needed. Our data suggest that there is a need for greater standardization of gait-analysis training.

The relationship between cost estimates reliability and BIM adoption: SEM analysis

Science.gov (United States)

Ismail, N. A. A.; Idris, N. H.; Ramli, H.; Rooshdi, R. R. Raja Muhammad; Sahamir, S. R.

2018-02-01

This paper presents the usage of Structural Equation Modelling (SEM) approach in analysing the effects of Building Information Modelling (BIM) technology adoption in improving the reliability of cost estimates. Based on the questionnaire survey results, SEM analysis using SPSS-AMOS application examined the relationships between BIM-improved information and cost estimates reliability factors, leading to BIM technology adoption. Six hypotheses were established prior to SEM analysis employing two types of SEM models, namely the Confirmatory Factor Analysis (CFA) model and full structural model. The SEM models were then validated through the assessment on their uni-dimensionality, validity, reliability, and fitness index, in line with the hypotheses tested. The final SEM model fit measures are: P-value=0.000, RMSEA=0.0790.90, TLI=0.956>0.90, NFI=0.935>0.90 and ChiSq/df=2.259; indicating that the overall index values achieved the required level of model fitness. The model supports all the hypotheses evaluated, confirming that all relationship exists amongst the constructs are positive and significant. Ultimately, the analysis verified that most of the respondents foresee better understanding of project input information through BIM visualization, its reliable database and coordinated data, in developing more reliable cost estimates. They also perceive to accelerate their cost estimating task through BIM adoption.

Reliability analysis of self-actuated shutdown system

International Nuclear Information System (INIS)

Itooka, S.; Kumasaka, K.; Okabe, A.; Satoh, K.; Tsukui, Y.

1991-01-01

An analytical study was performed for the reliability of a self-actuated shutdown system (SASS) under the unprotected loss of flow (ULOF) event in a typical loop-type liquid metal fast breeder reactor (LMFBR) by the use of the response surface Monte Carlo analysis method. Dominant parameters for the SASS, such as Curie point characteristics, subassembly outlet coolant temperature, electromagnetic surface condition, etc., were selected and their probability density functions (PDFs) were determined by the design study information and experimental data. To get the response surface function (RSF) for the maximum coolant temperature, transient analyses of ULOF were performed by utilizing the experimental design method in the determination of analytical cases. Then, the RSF was derived by the multi-variable regression analysis. The unreliability of the SASS was evaluated as a probability that the maximum coolant temperature exceeded an acceptable level, employing the Monte Carlo calculation using the above PDFs and RSF. In this study, sensitivities to the dominant parameter were compared. The dispersion of subassembly outlet coolant temperature near the SASS-was found to be one of the most sensitive parameters. Fault tree analysis was performed using this value for the SASS in order to evaluate the shutdown system reliability. As a result of this study, the effectiveness of the SASS on the reliability improvement in the LMFBR shutdown system was analytically confirmed. This study has been performed as a part of joint research and development projects for DFBR under the sponsorship of the nine Japanese electric power companies, Electric Power Development Company and the Japan Atomic Power Company. (author)

Reliability analysis framework for computer-assisted medical decision systems

International Nuclear Information System (INIS)

Habas, Piotr A.; Zurada, Jacek M.; Elmaghraby, Adel S.; Tourassi, Georgia D.

2007-01-01

We present a technique that enhances computer-assisted decision (CAD) systems with the ability to assess the reliability of each individual decision they make. Reliability assessment is achieved by measuring the accuracy of a CAD system with known cases similar to the one in question. The proposed technique analyzes the feature space neighborhood of the query case to dynamically select an input-dependent set of known cases relevant to the query. This set is used to assess the local (query-specific) accuracy of the CAD system. The estimated local accuracy is utilized as a reliability measure of the CAD response to the query case. The underlying hypothesis of the study is that CAD decisions with higher reliability are more accurate. The above hypothesis was tested using a mammographic database of 1337 regions of interest (ROIs) with biopsy-proven ground truth (681 with masses, 656 with normal parenchyma). Three types of decision models, (i) a back-propagation neural network (BPNN), (ii) a generalized regression neural network (GRNN), and (iii) a support vector machine (SVM), were developed to detect masses based on eight morphological features automatically extracted from each ROI. The performance of all decision models was evaluated using the Receiver Operating Characteristic (ROC) analysis. The study showed that the proposed reliability measure is a strong predictor of the CAD system's case-specific accuracy. Specifically, the ROC area index for CAD predictions with high reliability was significantly better than for those with low reliability values. This result was consistent across all decision models investigated in the study. The proposed case-specific reliability analysis technique could be used to alert the CAD user when an opinion that is unlikely to be reliable is offered. The technique can be easily deployed in the clinical environment because it is applicable with a wide range of classifiers regardless of their structure and it requires neither additional

Social Cost Benefit Analysis of HL-LHC

CERN Document Server

Bastianin, Andrea

2018-01-01

We present a Social Cost–Benefit Analysis (CBA) of the High Luminosity upgrade of the Large Hadron Collider (HL-LHC), assessing its economic costs and benefits up to 2038. The Net Present Value (NPV) of the HL-LHC project is positive at the end of the observation period. The ratio between incremental benefits and incremental costs of the HL-LHC with respect to continue operating the LHC under normal consolidation (i.e. without high-luminosity upgrade) is slightly over 1.7, meaning that each Swiss Franc invested in the HL-LHC upgrade project pays back approximately 1.7 CHF in societal benefits. Simulations based on 50000 Monte Carlo rounds show that there is a 94% chance to observe a positive NPV (i.e. a quantifiable economic benefit for the society). The attractiveness of CERN for Early Stage Researchers (ESR) is key for a positive CBA result. Given that benefits to ESRs are the single most important societal benefit, CERN should invest more in activities facilitating the transition to the international job...

A Note on the Validity and Reliability of Multi-Criteria Decision Analysis for the Benefit-Risk Assessment of Medicines.

Science.gov (United States)

Garcia-Hernandez, Alberto

2015-11-01

The comparative evaluation of benefits and risks is one of the most important tasks during the development, market authorization and post-approval pharmacovigilance of medicinal products. Multi-criteria decision analysis (MCDA) has been recommended to support decision making in the benefit-risk assessment (BRA) of medicines. This paper identifies challenges associated with bias or variability that practitioners may encounter in this field and presents solutions to overcome them. The inclusion of overlapping or preference-complementary criteria, which are frequent violations to the assumptions of this model, should be avoided. For each criterion, a value function translates the original outcomes into preference-related scores. Applying non-linear value functions to criteria defined as the risk of suffering a certain event during the study introduces specific risk behaviours in this prescriptive, rather than descriptive, model and is therefore a questionable practice. MCDA uses weights to compare the importance of the model criteria with each other; during their elicitation a frequent situation where (generally favourable) mild effects are directly traded off against low probabilities of suffering (generally unfavourable) severe effects during the study is known to lead to biased and variable weights and ought to be prevented. The way the outcomes are framed during the elicitation process, positively versus negatively for instance, may also lead to differences in the preference weights, warranting an appropriate justification during each implementation. Finally, extending the weighted-sum MCDA model into a fully inferential tool through a probabilistic sensitivity analysis is desirable. However, this task is troublesome and should not ignore that clinical trial endpoints generally are positively correlated.

A survey on reliability and safety analysis techniques of robot systems in nuclear power plants

Energy Technology Data Exchange (ETDEWEB)

Eom, H S; Kim, J H; Lee, J C; Choi, Y R; Moon, S S

2000-12-01

The reliability and safety analysis techniques was surveyed for the purpose of overall quality improvement of reactor inspection system which is under development in our current project. The contents of this report are : 1. Reliability and safety analysis techniques suvey - Reviewed reliability and safety analysis techniques are generally accepted techniques in many industries including nuclear industry. And we selected a few techniques which are suitable for our robot system. They are falut tree analysis, failure mode and effect analysis, reliability block diagram, markov model, combinational method, and simulation method. 2. Survey on the characteristics of robot systems which are distinguished from other systems and which are important to the analysis. 3. Survey on the nuclear environmental factors which affect the reliability and safety analysis of robot system 4. Collection of the case studies of robot reliability and safety analysis which are performed in foreign countries. The analysis results of this survey will be applied to the improvement of reliability and safety of our robot system and also will be used for the formal qualification and certification of our reactor inspection system.

A survey on reliability and safety analysis techniques of robot systems in nuclear power plants

International Nuclear Information System (INIS)

Eom, H.S.; Kim, J.H.; Lee, J.C.; Choi, Y.R.; Moon, S.S.

2000-12-01

The reliability and safety analysis techniques was surveyed for the purpose of overall quality improvement of reactor inspection system which is under development in our current project. The contents of this report are : 1. Reliability and safety analysis techniques suvey - Reviewed reliability and safety analysis techniques are generally accepted techniques in many industries including nuclear industry. And we selected a few techniques which are suitable for our robot system. They are falut tree analysis, failure mode and effect analysis, reliability block diagram, markov model, combinational method, and simulation method. 2. Survey on the characteristics of robot systems which are distinguished from other systems and which are important to the analysis. 3. Survey on the nuclear environmental factors which affect the reliability and safety analysis of robot system 4. Collection of the case studies of robot reliability and safety analysis which are performed in foreign countries. The analysis results of this survey will be applied to the improvement of reliability and safety of our robot system and also will be used for the formal qualification and certification of our reactor inspection system

Reliability analysis of service water system under earthquake

International Nuclear Information System (INIS)

Yu Yu; Qian Xiaoming; Lu Xuefeng; Wang Shengfei; Niu Fenglei

2013-01-01

Service water system is one of the important safety systems in nuclear power plant, whose failure probability is always gained by system reliability analysis. The probability of equipment failure under the earthquake is the function of the peak acceleration of earthquake motion, while the occurrence of earthquake is of randomicity, thus the traditional fault tree method in current probability safety assessment is not powerful enough to deal with such case of conditional probability problem. An analysis frame was put forward for system reliability evaluation in seismic condition in this paper, in which Monte Carlo simulation was used to deal with conditional probability problem. Annual failure probability of service water system was calculated, and failure probability of 1.46X10 -4 per year was obtained. The analysis result is in accordance with the data which indicate equipment seismic resistance capability, and the rationality of the model is validated. (authors)

Reliability demonstration test planning: A three dimensional consideration

International Nuclear Information System (INIS)

Yadav, Om Prakash; Singh, Nanua; Goel, Parveen S.

2006-01-01

Increasing customer demand for reliability, fierce market competition on time-to-market and cost, and highly reliable products are making reliability testing more challenging task. This paper presents a systematic approach for identifying critical elements (subsystems and components) of the system and deciding the types of test to be performed to demonstrate reliability. It decomposes the system into three dimensions (i.e. physical, functional and time) and identifies critical elements in the design by allocating system level reliability to each candidate. The decomposition of system level reliability is achieved by using criticality index. The numerical value of criticality index for each candidate is derived based on the information available from failure mode and effects analysis (FMEA) document or warranty data from a prior system. It makes use of this information to develop reliability demonstration test plan for the identified (critical) failure mechanisms and physical elements. It also highlights the benefits of using prior information in order to locate critical spots in the design and in subsequent development of test plans. A case example is presented to demonstrate the proposed approach

Small nuclear power reactor emergency electric power supply system reliability comparative analysis

International Nuclear Information System (INIS)

Bonfietti, Gerson

2003-01-01

This work presents an analysis of the reliability of the emergency power supply system, of a small size nuclear power reactor. Three different configurations are investigated and their reliability analyzed. The fault tree method is used as the main tool of analysis. The work includes a bibliographic review of emergency diesel generator reliability and a discussion of the design requirements applicable to emergency electrical systems. The influence of common cause failure influences is considered using the beta factor model. The operator action is considered using human failure probabilities. A parametric analysis shows the strong dependence between the reactor safety and the loss of offsite electric power supply. It is also shown that common cause failures can be a major contributor to the system reliability. (author)

Incremental ALARA cost/benefit computer analysis

International Nuclear Information System (INIS)

Hamby, P.

1987-01-01

Commonwealth Edison Company has developed and is testing an enhanced Fortran Computer Program to be used for cost/benefit analysis of Radiation Reduction Projects at its six nuclear power facilities and Corporate Technical Support Groups. This paper describes a Macro-Diven IBM Mainframe Program comprised of two different types of analyses-an Abbreviated Program with fixed costs and base values, and an extended Engineering Version for a detailed, more through and time-consuming approach. The extended engineering version breaks radiation exposure costs down into two components-Health-Related Costs and Replacement Labor Costs. According to user input, the program automatically adjust these two cost components and applies the derivation to company economic analyses such as replacement power costs, carrying charges, debt interest, and capital investment cost. The results from one of more program runs using different parameters may be compared in order to determine the most appropriate ALARA dose reduction technique. Benefits of this particular cost / benefit analysis technique includes flexibility to accommodate a wide range of user data and pre-job preparation, as well as the use of proven and standardized company economic equations

Reliability Evaluation of Machine Center Components Based on Cascading Failure Analysis

Science.gov (United States)

Zhang, Ying-Zhi; Liu, Jin-Tong; Shen, Gui-Xiang; Long, Zhe; Sun, Shu-Guang

2017-07-01

In order to rectify the problems that the component reliability model exhibits deviation, and the evaluation result is low due to the overlook of failure propagation in traditional reliability evaluation of machine center components, a new reliability evaluation method based on cascading failure analysis and the failure influenced degree assessment is proposed. A direct graph model of cascading failure among components is established according to cascading failure mechanism analysis and graph theory. The failure influenced degrees of the system components are assessed by the adjacency matrix and its transposition, combined with the Pagerank algorithm. Based on the comprehensive failure probability function and total probability formula, the inherent failure probability function is determined to realize the reliability evaluation of the system components. Finally, the method is applied to a machine center, it shows the following: 1) The reliability evaluation values of the proposed method are at least 2.5% higher than those of the traditional method; 2) The difference between the comprehensive and inherent reliability of the system component presents a positive correlation with the failure influenced degree of the system component, which provides a theoretical basis for reliability allocation of machine center system.

Optimizing the design and operation of reactor emergency systems using reliability analysis techniques

International Nuclear Information System (INIS)

Snaith, E.R.

1975-01-01

Following a reactor trip various reactor emergency systems, e.g. essential power supplies, emergency core cooling and boiler feed water arrangements are required to operate with a high degree of reliability. These systems must therefore be critically assessed to confirm their capability of operation and determine their reliability of performance. The use of probability analysis techniques enables the potential operating reliability of the systems to be calculated and this can then be compared with the overall reliability requirements. However, a system reliability analysis does much more than calculate an overall reliability value for the system. It establishes the reliability of all parts of the system and thus identifies the most sensitive areas of unreliability. This indicates the areas where any required improvements should be made and enables the overall systems' designs and modes of operation to be optimized, to meet the system and hence the overall reactor safety criteria. This paper gives specific examples of sensitive areas of unreliability that were identified as a result of a reliability analysis that was carried out on a reactor emergency core cooling system. Details are given of modifications to design and operation that were implemented with a resulting improvement in reliability of various reactor sub-systems. The report concludes that an initial calculation of system reliability should represent only the beginning of continuing process of system assessment. Data on equipment and system performance, particularly in those areas shown to be sensitive in their effect on the overall nuclear power plant reliability, should be collected and processed to give reliability data. These data should then be applied in further probabilistic analyses and the results correlated with the original analysis. This will demonstrate whether the required and the originally predicted system reliability is likely to be achieved, in the light of the actual history to date of

Structural reliability analysis and seismic risk assessment

International Nuclear Information System (INIS)

Hwang, H.; Reich, M.; Shinozuka, M.

1984-01-01

This paper presents a reliability analysis method for safety evaluation of nuclear structures. By utilizing this method, it is possible to estimate the limit state probability in the lifetime of structures and to generate analytically the fragility curves for PRA studies. The earthquake ground acceleration, in this approach, is represented by a segment of stationary Gaussian process with a zero mean and a Kanai-Tajimi Spectrum. All possible seismic hazard at a site represented by a hazard curve is also taken into consideration. Furthermore, the limit state of a structure is analytically defined and the corresponding limit state surface is then established. Finally, the fragility curve is generated and the limit state probability is evaluated. In this paper, using a realistic reinforced concrete containment as an example, results of the reliability analysis of the containment subjected to dead load, live load and ground earthquake acceleration are presented and a fragility curve for PRA studies is also constructed

Recent advances in computational structural reliability analysis methods

Science.gov (United States)

Thacker, Ben H.; Wu, Y.-T.; Millwater, Harry R.; Torng, Tony Y.; Riha, David S.

1993-10-01

The goal of structural reliability analysis is to determine the probability that the structure will adequately perform its intended function when operating under the given environmental conditions. Thus, the notion of reliability admits the possibility of failure. Given the fact that many different modes of failure are usually possible, achievement of this goal is a formidable task, especially for large, complex structural systems. The traditional (deterministic) design methodology attempts to assure reliability by the application of safety factors and conservative assumptions. However, the safety factor approach lacks a quantitative basis in that the level of reliability is never known and usually results in overly conservative designs because of compounding conservatisms. Furthermore, problem parameters that control the reliability are not identified, nor their importance evaluated. A summary of recent advances in computational structural reliability assessment is presented. A significant level of activity in the research and development community was seen recently, much of which was directed towards the prediction of failure probabilities for single mode failures. The focus is to present some early results and demonstrations of advanced reliability methods applied to structural system problems. This includes structures that can fail as a result of multiple component failures (e.g., a redundant truss), or structural components that may fail due to multiple interacting failure modes (e.g., excessive deflection, resonate vibration, or creep rupture). From these results, some observations and recommendations are made with regard to future research needs.

Reliability Analysis Study of Digital Reactor Protection System in Nuclear Power Plant

International Nuclear Information System (INIS)

Guo, Xiao Ming; Liu, Tao; Tong, Jie Juan; Zhao, Jun

2011-01-01

The Digital I and C systems are believed to improve a plants safety and reliability generally. The reliability analysis of digital I and C system has become one research hotspot. Traditional fault tree method is one of means to quantify the digital I and C system reliability. Review of advanced nuclear power plant AP1000 digital protection system evaluation makes clear both the fault tree application and analysis process to the digital system reliability. One typical digital protection system special for advanced reactor has been developed, which reliability evaluation is necessary for design demonstration. The typical digital protection system construction is introduced in the paper, and the process of FMEA and fault tree application to the digital protection system reliability evaluation are described. Reliability data and bypass logic modeling are two points giving special attention in the paper. Because the factors about time sequence and feedback not exist in reactor protection system obviously, the dynamic feature of digital system is not discussed

Efficient surrogate models for reliability analysis of systems with multiple failure modes

International Nuclear Information System (INIS)

Bichon, Barron J.; McFarland, John M.; Mahadevan, Sankaran

2011-01-01

Despite many advances in the field of computational reliability analysis, the efficient estimation of the reliability of a system with multiple failure modes remains a persistent challenge. Various sampling and analytical methods are available, but they typically require accepting a tradeoff between accuracy and computational efficiency. In this work, a surrogate-based approach is presented that simultaneously addresses the issues of accuracy, efficiency, and unimportant failure modes. The method is based on the creation of Gaussian process surrogate models that are required to be locally accurate only in the regions of the component limit states that contribute to system failure. This approach to constructing surrogate models is demonstrated to be both an efficient and accurate method for system-level reliability analysis. - Highlights: → Extends efficient global reliability analysis to systems with multiple failure modes. → Constructs locally accurate Gaussian process models of each response. → Highly efficient and accurate method for assessing system reliability. → Effectiveness is demonstrated on several test problems from the literature.

Exploratory factor analysis and reliability analysis with missing data: A simple method for SPSS users

Directory of Open Access Journals (Sweden)

Bruce Weaver

2014-09-01

Full Text Available Missing data is a frequent problem for researchers conducting exploratory factor analysis (EFA or reliability analysis. The SPSS FACTOR procedure allows users to select listwise deletion, pairwise deletion or mean substitution as a method for dealing with missing data. The shortcomings of these methods are well-known. Graham (2009 argues that a much better way to deal with missing data in this context is to use a matrix of expectation maximization (EM covariances(or correlations as input for the analysis. SPSS users who have the Missing Values Analysis add-on module can obtain vectors ofEM means and standard deviations plus EM correlation and covariance matrices via the MVA procedure. But unfortunately, MVA has no /MATRIX subcommand, and therefore cannot write the EM correlations directly to a matrix dataset of the type needed as input to the FACTOR and RELIABILITY procedures. We describe two macros that (in conjunction with an intervening MVA command carry out the data management steps needed to create two matrix datasets, one containing EM correlations and the other EM covariances. Either of those matrix datasets can then be used asinput to the FACTOR procedure, and the EM correlations can also be used as input to RELIABILITY. We provide an example that illustrates the use of the two macros to generate the matrix datasets and how to use those datasets as input to the FACTOR and RELIABILITY procedures. We hope that this simple method for handling missing data will prove useful to both students andresearchers who are conducting EFA or reliability analysis.

Reliability analysis of the solar array based on Fault Tree Analysis

International Nuclear Information System (INIS)

Wu Jianing; Yan Shaoze

2011-01-01

The solar array is an important device used in the spacecraft, which influences the quality of in-orbit operation of the spacecraft and even the launches. This paper analyzes the reliability of the mechanical system and certifies the most vital subsystem of the solar array. The fault tree analysis (FTA) model is established according to the operating process of the mechanical system based on DFH-3 satellite; the logical expression of the top event is obtained by Boolean algebra and the reliability of the solar array is calculated. The conclusion shows that the hinges are the most vital links between the solar arrays. By analyzing the structure importance(SI) of the hinge's FTA model, some fatal causes, including faults of the seal, insufficient torque of the locking spring, temperature in space, and friction force, can be identified. Damage is the initial stage of the fault, so limiting damage is significant to prevent faults. Furthermore, recommendations for improving reliability associated with damage limitation are discussed, which can be used for the redesigning of the solar array and the reliability growth planning.

Reliability analysis of the solar array based on Fault Tree Analysis

Energy Technology Data Exchange (ETDEWEB)

Wu Jianing; Yan Shaoze, E-mail: yansz@mail.tsinghua.edu.cn [State Key Laboratory of Tribology, Department of Precision Instruments and Mechanology, Tsinghua University,Beijing 100084 (China)

2011-07-19

The solar array is an important device used in the spacecraft, which influences the quality of in-orbit operation of the spacecraft and even the launches. This paper analyzes the reliability of the mechanical system and certifies the most vital subsystem of the solar array. The fault tree analysis (FTA) model is established according to the operating process of the mechanical system based on DFH-3 satellite; the logical expression of the top event is obtained by Boolean algebra and the reliability of the solar array is calculated. The conclusion shows that the hinges are the most vital links between the solar arrays. By analyzing the structure importance(SI) of the hinge's FTA model, some fatal causes, including faults of the seal, insufficient torque of the locking spring, temperature in space, and friction force, can be identified. Damage is the initial stage of the fault, so limiting damage is significant to prevent faults. Furthermore, recommendations for improving reliability associated with damage limitation are discussed, which can be used for the redesigning of the solar array and the reliability growth planning.

Kuhn-Tucker optimization based reliability analysis for probabilistic finite elements

Science.gov (United States)

Liu, W. K.; Besterfield, G.; Lawrence, M.; Belytschko, T.

1988-01-01

The fusion of probability finite element method (PFEM) and reliability analysis for fracture mechanics is considered. Reliability analysis with specific application to fracture mechanics is presented, and computational procedures are discussed. Explicit expressions for the optimization procedure with regard to fracture mechanics are given. The results show the PFEM is a very powerful tool in determining the second-moment statistics. The method can determine the probability of failure or fracture subject to randomness in load, material properties and crack length, orientation, and location.

Test-retest reliability of trunk accelerometric gait analysis

DEFF Research Database (Denmark)

Henriksen, Marius; Lund, Hans; Moe-Nilssen, R

2004-01-01

The purpose of this study was to determine the test-retest reliability of a trunk accelerometric gait analysis in healthy subjects. Accelerations were measured during walking using a triaxial accelerometer mounted on the lumbar spine of the subjects. Six men and 14 women (mean age 35.2; range 18...... a definite potential in clinical gait analysis....

Developing safety performance functions incorporating reliability-based risk measures.

Science.gov (United States)

Ibrahim, Shewkar El-Bassiouni; Sayed, Tarek

2011-11-01

Current geometric design guides provide deterministic standards where the safety margin of the design output is generally unknown and there is little knowledge of the safety implications of deviating from these standards. Several studies have advocated probabilistic geometric design where reliability analysis can be used to account for the uncertainty in the design parameters and to provide a risk measure of the implication of deviation from design standards. However, there is currently no link between measures of design reliability and the quantification of safety using collision frequency. The analysis presented in this paper attempts to bridge this gap by incorporating a reliability-based quantitative risk measure such as the probability of non-compliance (P(nc)) in safety performance functions (SPFs). Establishing this link will allow admitting reliability-based design into traditional benefit-cost analysis and should lead to a wider application of the reliability technique in road design. The present application is concerned with the design of horizontal curves, where the limit state function is defined in terms of the available (supply) and stopping (demand) sight distances. A comprehensive collision and geometric design database of two-lane rural highways is used to investigate the effect of the probability of non-compliance on safety. The reliability analysis was carried out using the First Order Reliability Method (FORM). Two Negative Binomial (NB) SPFs were developed to compare models with and without the reliability-based risk measures. It was found that models incorporating the P(nc) provided a better fit to the data set than the traditional (without risk) NB SPFs for total, injury and fatality (I+F) and property damage only (PDO) collisions. Copyright © 2011 Elsevier Ltd. All rights reserved.

Reliability analysis and initial requirements for FC systems and stacks

Science.gov (United States)

Åström, K.; Fontell, E.; Virtanen, S.

In the year 2000 Wärtsilä Corporation started an R&D program to develop SOFC systems for CHP applications. The program aims to bring to the market highly efficient, clean and cost competitive fuel cell systems with rated power output in the range of 50-250 kW for distributed generation and marine applications. In the program Wärtsilä focuses on system integration and development. System reliability and availability are key issues determining the competitiveness of the SOFC technology. In Wärtsilä, methods have been implemented for analysing the system in respect to reliability and safety as well as for defining reliability requirements for system components. A fault tree representation is used as the basis for reliability prediction analysis. A dynamic simulation technique has been developed to allow for non-static properties in the fault tree logic modelling. Special emphasis has been placed on reliability analysis of the fuel cell stacks in the system. A method for assessing reliability and critical failure predictability requirements for fuel cell stacks in a system consisting of several stacks has been developed. The method is based on a qualitative model of the stack configuration where each stack can be in a functional, partially failed or critically failed state, each of the states having different failure rates and effects on the system behaviour. The main purpose of the method is to understand the effect of stack reliability, critical failure predictability and operating strategy on the system reliability and availability. An example configuration, consisting of 5 × 5 stacks (series of 5 sets of 5 parallel stacks) is analysed in respect to stack reliability requirements as a function of predictability of critical failures and Weibull shape factor of failure rate distributions.

Reliability analysis of maintenance operations for railway tracks

International Nuclear Information System (INIS)

Rhayma, N.; Bressolette, Ph.; Breul, P.; Fogli, M.; Saussine, G.

2013-01-01

Railway engineering is confronted with problems due to degradation of the railway network that requires important and costly maintenance work. However, because of the lack of knowledge on the geometrical and mechanical parameters of the track, it is difficult to optimize the maintenance management. In this context, this paper presents a new methodology to analyze the behavior of railway tracks. It combines new diagnostic devices which permit to obtain an important amount of data and thus to make statistics on the geometric and mechanical parameters and a non-intrusive stochastic approach which can be coupled with any mechanical model. Numerical results show the possibilities of this methodology for reliability analysis of different maintenance operations. In the future this approach will give important informations to railway managers to optimize maintenance operations using a reliability analysis

Distribution System Reliability Analysis for Smart Grid Applications

Science.gov (United States)

Aljohani, Tawfiq Masad

Reliability of power systems is a key aspect in modern power system planning, design, and operation. The ascendance of the smart grid concept has provided high hopes of developing an intelligent network that is capable of being a self-healing grid, offering the ability to overcome the interruption problems that face the utility and cost it tens of millions in repair and loss. To address its reliability concerns, the power utilities and interested parties have spent extensive amount of time and effort to analyze and study the reliability of the generation and transmission sectors of the power grid. Only recently has attention shifted to be focused on improving the reliability of the distribution network, the connection joint between the power providers and the consumers where most of the electricity problems occur. In this work, we will examine the effect of the smart grid applications in improving the reliability of the power distribution networks. The test system used in conducting this thesis is the IEEE 34 node test feeder, released in 2003 by the Distribution System Analysis Subcommittee of the IEEE Power Engineering Society. The objective is to analyze the feeder for the optimal placement of the automatic switching devices and quantify their proper installation based on the performance of the distribution system. The measures will be the changes in the reliability system indices including SAIDI, SAIFI, and EUE. The goal is to design and simulate the effect of the installation of the Distributed Generators (DGs) on the utility's distribution system and measure the potential improvement of its reliability. The software used in this work is DISREL, which is intelligent power distribution software that is developed by General Reliability Co.

Reliability analysis and utilization of PEMs in space application

Science.gov (United States)

Jiang, Xiujie; Wang, Zhihua; Sun, Huixian; Chen, Xiaomin; Zhao, Tianlin; Yu, Guanghua; Zhou, Changyi

2009-11-01

More and more plastic encapsulated microcircuits (PEMs) are used in space missions to achieve high performance. Since PEMs are designed for use in terrestrial operating conditions, the successful usage of PEMs in space harsh environment is closely related to reliability issues, which should be considered firstly. However, there is no ready-made methodology for PEMs in space applications. This paper discusses the reliability for the usage of PEMs in space. This reliability analysis can be divided into five categories: radiation test, radiation hardness, screening test, reliability calculation and reliability assessment. One case study is also presented to illuminate the details of the process, in which a PEM part is used in a joint space program Double-Star Project between the European Space Agency (ESA) and China. The influence of environmental constrains including radiation, humidity, temperature and mechanics on the PEM part has been considered. Both Double-Star Project satellites are still running well in space now.

Reliability analysis for new technology-based transmitters

Energy Technology Data Exchange (ETDEWEB)

Brissaud, Florent, E-mail: florent.brissaud.2007@utt.f [Institut National de l' Environnement Industriel et des Risques (INERIS), Parc Technologique Alata, BP 2, 60550 Verneuil-en-Halatte (France); Universite de Technologie de Troyes (UTT), Institut Charles Delaunay (ICD) and STMR UMR CNRS 6279, 12 rue Marie Curie, BP 2060, 10010 Troyes cedex (France); Barros, Anne; Berenguer, Christophe [Universite de Technologie de Troyes (UTT), Institut Charles Delaunay (ICD) and STMR UMR CNRS 6279, 12 rue Marie Curie, BP 2060, 10010 Troyes cedex (France); Charpentier, Dominique [Institut National de l' Environnement Industriel et des Risques (INERIS), Parc Technologique Alata, BP 2, 60550 Verneuil-en-Halatte (France)

2011-02-15

The reliability analysis of new technology-based transmitters has to deal with specific issues: various interactions between both material elements and functions, undefined behaviours under faulty conditions, several transmitted data, and little reliability feedback. To handle these particularities, a '3-step' model is proposed, based on goal tree-success tree (GTST) approaches to represent both the functional and material aspects, and includes the faults and failures as a third part for supporting reliability analyses. The behavioural aspects are provided by relationship matrices, also denoted master logic diagrams (MLD), with stochastic values which represent direct relationships between system elements. Relationship analyses are then proposed to assess the effect of any fault or failure on any material element or function. Taking these relationships into account, the probabilities of malfunction and failure modes are evaluated according to time. Furthermore, uncertainty analyses tend to show that even if the input data and system behaviour are not well known, these previous results can be obtained in a relatively precise way. An illustration is provided by a case study on an infrared gas transmitter. These properties make the proposed model and corresponding reliability analyses especially suitable for intelligent transmitters (or 'smart sensors').

Reliability on intra-laboratory and inter-laboratory data of hair mineral analysis comparing with blood analysis.

Science.gov (United States)

Namkoong, Sun; Hong, Seung Phil; Kim, Myung Hwa; Park, Byung Cheol

2013-02-01

Nowadays, although its clinical value remains controversial institutions utilize hair mineral analysis. Arguments about the reliability of hair mineral analysis persist, and there have been evaluations of commercial laboratories performing hair mineral analysis. The objective of this study was to assess the reliability of intra-laboratory and inter-laboratory data at three commercial laboratories conducting hair mineral analysis, compared to serum mineral analysis. Two divided hair samples taken from near the scalp were submitted for analysis at the same time, to all laboratories, from one healthy volunteer. Each laboratory sent a report consisting of quantitative results and their interpretation of health implications. Differences among intra-laboratory and interlaboratory data were analyzed using SPSS version 12.0 (SPSS Inc., USA). All the laboratories used identical methods for quantitative analysis, and they generated consistent numerical results according to Friedman analysis of variance. However, the normal reference ranges of each laboratory varied. As such, each laboratory interpreted the patient's health differently. On intra-laboratory data, Wilcoxon analysis suggested they generated relatively coherent data, but laboratory B could not in one element, so its reliability was doubtful. In comparison with the blood test, laboratory C generated identical results, but not laboratory A and B. Hair mineral analysis has its limitations, considering the reliability of inter and intra laboratory analysis comparing with blood analysis. As such, clinicians should be cautious when applying hair mineral analysis as an ancillary tool. Each laboratory included in this study requires continuous refinement from now on for inducing standardized normal reference levels.

Construct validity and reliability of a checklist for volleyball serve analysis

Directory of Open Access Journals (Sweden)

Cicero Luciano Alves Costa

2018-03-01

Full Text Available This study aims to investigate the construct validity and reliability of the checklist for qualitative analysis of the overhand serve in Volleyball. Fifty-five male subjects aged 13-17 years participated in the study. The overhand serve was analyzed using the checklist proposed by Meira Junior (2003, which analyzes the pattern of serve movement in four phases: (I initial position, (II ball lifting, (III ball attacking, and (IV finalization. Construct validity was analyzed using confirmatory factorial analysis and reliability through the Cronbach’s alpha coefficient. The construct validity was supported by confirmatory factor analysis with the RMSEA results (0.037 [confidence interval 90% = 0.020-0.040], CFI (0.970 and TLI (0.950 indicating good fit of the model. In relation to reliability, Cronbach’s alpha coefficient was 0.661, being this value considered acceptable. Among the items on the checklist, ball lifting and attacking showed higher factor loadings, 0.69 and 0.99, respectively. In summary, the checklist for the qualitative analysis of the overhand serve of Meira Junior (2003 can be considered a valid and reliable instrument for use in research in the field of Sports Sciences.

Reliability analysis of nuclear containment without metallic liners against jet aircraft crash

Energy Technology Data Exchange (ETDEWEB)

Siddiqui, N.A.; Iqbal, M.A.; Abbas, H. E-mail: abbas_husain@hotmail.com; Paul, D.K

2003-09-01

The present study presents a methodology for detailed reliability analysis of nuclear containment without metallic liners against aircraft crash. For this purpose, a nonlinear limit state function has been derived using violation of tolerable crack width as failure criterion. This criterion has been considered as failure criterion because radioactive radiations may come out if size of crack becomes more than the tolerable crack width. The derived limit state uses the response of containment that has been obtained from a detailed dynamic analysis of nuclear containment under an impact of a large size Boeing jet aircraft. Using this response in conjunction with limit state function, the reliabilities and probabilities of failures are obtained at a number of vulnerable locations employing an efficient first-order reliability method (FORM). These values of reliability and probability of failure at various vulnerable locations are then used for the estimation of conditional and annual reliabilities of nuclear containment as a function of its location from the airport. To study the influence of the various random variables on containment reliability the sensitivity analysis has been performed. Some parametric studies have also been included to obtain the results of field and academic interest.

[Reliability theory based on quality risk network analysis for Chinese medicine injection].

Science.gov (United States)

Li, Zheng; Kang, Li-Yuan; Fan, Xiao-Hui

2014-08-01

A new risk analysis method based upon reliability theory was introduced in this paper for the quality risk management of Chinese medicine injection manufacturing plants. The risk events including both cause and effect ones were derived in the framework as nodes with a Bayesian network analysis approach. It thus transforms the risk analysis results from failure mode and effect analysis (FMEA) into a Bayesian network platform. With its structure and parameters determined, the network can be used to evaluate the system reliability quantitatively with probabilistic analytical appraoches. Using network analysis tools such as GeNie and AgenaRisk, we are able to find the nodes that are most critical to influence the system reliability. The importance of each node to the system can be quantitatively evaluated by calculating the effect of the node on the overall risk, and minimization plan can be determined accordingly to reduce their influences and improve the system reliability. Using the Shengmai injection manufacturing plant of SZYY Ltd as a user case, we analyzed the quality risk with both static FMEA analysis and dynamic Bayesian Network analysis. The potential risk factors for the quality of Shengmai injection manufacturing were identified with the network analysis platform. Quality assurance actions were further defined to reduce the risk and improve the product quality.

Integrated system reliability analysis

DEFF Research Database (Denmark)

Gintautas, Tomas; Sørensen, John Dalsgaard

Specific targets: 1) The report shall describe the state of the art of reliability and risk-based assessment of wind turbine components. 2) Development of methodology for reliability and risk-based assessment of the wind turbine at system level. 3) Describe quantitative and qualitative measures...

Practice of value-based distribution reliability assessment (VBDRA) at Scarborough Public Utilities

International Nuclear Information System (INIS)

Chen, R-L.

1995-01-01

The development of value-based distribution reliability assessment (VBDRA) at Scarborough Public Utilities was described. Load point reliability indices, customer interruption costs (CIC), continuity and service reliability, accuracy of CIC, and the aspects of application of VBDRA were addressed. The application of VBDRA to a long-term rebuild plan for 4.16 kV distribution system was described. The importance of a cost-benefit analysis for implementation of VBDRA was emphasized. In the case of the Scarborough Public Utilities Commission the enhanced feeder reliability assessment was found to influence the allocation of funding to where it provided the most value to customers. 14 refs., 3 tabs., 3 figs

ERP Reliability Analysis (ERA) Toolbox: An open-source toolbox for analyzing the reliability of event-related brain potentials.

Science.gov (United States)

Clayson, Peter E; Miller, Gregory A

2017-01-01

Generalizability theory (G theory) provides a flexible, multifaceted approach to estimating score reliability. G theory's approach to estimating score reliability has important advantages over classical test theory that are relevant for research using event-related brain potentials (ERPs). For example, G theory does not require parallel forms (i.e., equal means, variances, and covariances), can handle unbalanced designs, and provides a single reliability estimate for designs with multiple sources of error. This monograph provides a detailed description of the conceptual framework of G theory using examples relevant to ERP researchers, presents the algorithms needed to estimate ERP score reliability, and provides a detailed walkthrough of newly-developed software, the ERP Reliability Analysis (ERA) Toolbox, that calculates score reliability using G theory. The ERA Toolbox is open-source, Matlab software that uses G theory to estimate the contribution of the number of trials retained for averaging, group, and/or event types on ERP score reliability. The toolbox facilitates the rigorous evaluation of psychometric properties of ERP scores recommended elsewhere in this special issue. Copyright © 2016 Elsevier B.V. All rights reserved.

Cost benefit analysis of instrumentation, supervision and control systems for nuclear power plants

International Nuclear Information System (INIS)

Hagen, P.

1973-08-01

A cost benefit analysis is carried out on a BWR type reactor power plant in which an on-line computer performs plant supervision, reporting, logging, calibration and control functions, using display devices and plotters, while an off-line computer is available for bigger jobs such as fuel management calculations. All on-line functions are briefly described and specified. Three types of computer system are considered, a simplex system, a dual computer system and a multi-processor system. These systems are analysed with respect to reliability, back-up instrumentation requirements and costs. While the multiprocessor system gave in all cases the lowest annual failure costs, the margin to the duplex system was so small that hardware, maintenance and software costs would play an important role in making a decision. (JIW)

Analysis of benefits

OpenAIRE

Kováříková, Kamila

2012-01-01

This master thesis deals with employee benefits in the current labour market, especially from the perspective of young employees. The first part is focused on the theory of motivation and employee benefits also with their tax impact on employee's income. Employee benefits in the current labour market, employee's satisfaction and employer's attitude to this issue are analyzed in the second part of this thesis.

THE RELIABILITY ANALYSIS OF EXISTING REINFORCED CONCRETE PILES IN PERMAFROST REGIONS

Directory of Open Access Journals (Sweden)

Vladimir S. Utkin

2017-06-01

Full Text Available The article describes the general problem of safe operation of buildings and structures with the dynamics of permafrost in Russia and other countries. The global warming on Earth will lead to global disasters such as failures of buildings and structures. The main reason of these failures will be a reduction of bearing capacity and the reliability of foundations. It is necessary to organize the observations (monitoring for the process of reducing the bearing capacity of foundations to prevent such accidents and reduce negative consequences, to development of preventive measures and operational methods for the piles reliability analysis. The main load-bearing elements of the foundation are reinforced concrete piles and frozen ground. Reinforced concrete piles have a tendency to decrease the bearing capacity and reliability of the upper (aerial part and the part in the soil. The article discusses the problem of reliability analysis of existing reinforced concrete piles in upper part in permafrost regions by the reason of pile degradation in the contact zone of seasonal thawing and freezing soil. The evaluation of the probability of failure is important in itself, but also it important for the reliability of foundation: consisting of piles and frozen soil. Authors offers the methods for reliability analysis of upper part of reinforced concrete piles in the contact zone with seasonally thawed soil under different number of random variables (fuzzy variables in the design mathematical model of a limit state by the strength criterion.

Benefit-cost analysis framework for evaluating inter-city transit investment.

Science.gov (United States)

2008-10-01

This report describes the development and application of a benefit/cost analysis (BCA) model to support the evaluation of investment decisions for intercity bus services. The model recognizes two principle types of intercity bus benefits: benefits th...

Cost-benefit analysis in decision making for diagnostic radiology

International Nuclear Information System (INIS)

Fabrikant, J.I.; Hilberg, A.W.

1982-02-01

This paper reviews certain current concepts and methods relating to benefit-risk analysis, in terms of economic costs and raidation risks to health, in relation to the benefits from diagnostic radiology in clinical medicine

Reliability analysis of the service water system of Angra 1 reactor

International Nuclear Information System (INIS)

Tayt-Sohn, L.C.; Oliveira, L.F.S. de.

1984-01-01

A reliability analysis of the service water system is done aiming to use in the evaluation of the non reliability of the Component Cooling System (SRC) for great loss of cooling accidents in nuclear power plants. (E.G.) [pt

Reliability analysis of the service water system of Angra 1 reactor

International Nuclear Information System (INIS)

Oliveira, L.F.S. de; Fleming, P.V.; Frutuoso e Melo, P.F.F.; Tayt-Sohn, L.C.

1983-01-01

A reliability analysis of the service water system is done aiming to use in the evaluation of the non reliability of the component cooling system (SRC) for great loss of cooling accidents in nuclear power plants. (E.G.) [pt

A study in the reliability analysis method for nuclear power plant structures (I)

Energy Technology Data Exchange (ETDEWEB)

Oh, Byung Hwan; Choi, Seong Cheol; Shin, Ho Sang; Yang, In Hwan; Kim, Yi Sung; Yu, Young; Kim, Se Hun [Seoul, Nationl Univ., Seoul (Korea, Republic of)

1999-03-15

Nuclear power plant structures may be exposed to aggressive environmental effects that may cause their strength and stiffness to decrease over their service life. Although the physics of these damage mechanisms are reasonably well understood and quantitative evaluation of their effects on time-dependent structural behavior is possible in some instances, such evaluations are generally very difficult and remain novel. The assessment of existing steel containment in nuclear power plants for continued service must provide quantitative evidence that they are able to withstand future extreme loads during a service period with an acceptable level of reliability. Rational methodologies to perform the reliability assessment can be developed from mechanistic models of structural deterioration, using time-dependent structural reliability analysis to take loading and strength uncertainties into account. The final goal of this study is to develop the analysis method for the reliability of containment structures. The cause and mechanism of corrosion is first clarified and the reliability assessment method has been established. By introducing the equivalent normal distribution, the procedure of reliability analysis which can determine the failure probabilities has been established. The influence of design variables to reliability and the relation between the reliability and service life will be continued second year research.

Reliability Analysis of Free Jet Scour Below Dams

Directory of Open Access Journals (Sweden)

Chuanqi Li

2012-12-01

Full Text Available Current formulas for calculating scour depth below of a free over fall are mostly deterministic in nature and do not adequately consider the uncertainties of various scouring parameters. A reliability-based assessment of scour, taking into account uncertainties of parameters and coefficients involved, should be performed. This paper studies the reliability of a dam foundation under the threat of scour. A model for calculating the reliability of scour and estimating the probability of failure of the dam foundation subjected to scour is presented. The Maximum Entropy Method is applied to construct the probability density function (PDF of the performance function subject to the moment constraints. Monte Carlo simulation (MCS is applied for uncertainty analysis. An example is considered, and there liability of its scour is computed, the influence of various random variables on the probability failure is analyzed.

Costs and benefits of railway urban logistics: a prospective social cost benefit analysis

OpenAIRE

Gonzalez-Feliu, Jesus

2014-01-01

This paper presents a general framework to assess urban rail logistics suitability via a socio-economic cost benefit analysis. Firstly, we propose an overview on the basic notions of CBA and SCBA. Secondly, we identify and present the main types of costs and benefits or railway urban logistics services and the related final delivery services using low emission road vehicles to serve customers where the rail systems cannot. Thirdly, as an example of application, we propose to assess a scenario...

Reliability model analysis and primary experimental evaluation of laser triggered pulse trigger

International Nuclear Information System (INIS)

Chen Debiao; Yang Xinglin; Li Yuan; Li Jin

2012-01-01

High performance pulse trigger can enhance performance and stability of the PPS. It is necessary to evaluate the reliability of the LTGS pulse trigger, so we establish the reliability analysis model of this pulse trigger based on CARMES software, the reliability evaluation is accord with the statistical results. (authors)

Design and Analysis of Transport Protocols for Reliable High-Speed Communications

NARCIS (Netherlands)

Oláh, A.

1997-01-01

The design and analysis of transport protocols for reliable communications constitutes the topic of this dissertation. These transport protocols guarantee the sequenced and complete delivery of user data over networks which may lose, duplicate and reorder packets. Reliable transport services are

System Reliability Engineering

International Nuclear Information System (INIS)

Lim, Tae Jin

2005-02-01

This book tells of reliability engineering, which includes quality and reliability, reliability data, importance of reliability engineering, reliability and measure, the poisson process like goodness of fit test and the poisson arrival model, reliability estimation like exponential distribution, reliability of systems, availability, preventive maintenance such as replacement policies, minimal repair policy, shock models, spares, group maintenance and periodic inspection, analysis of common cause failure, and analysis model of repair effect.

Comment 1 on workshop in economics - a note on benefit-cost analysis and the distribution of benefits: The greenhouse effect

International Nuclear Information System (INIS)

Quinn, K.G.

1992-01-01

The application of benefit-cost analysis to environmental problems in general, and to global warming as demonstrated by Kosobud in particular, is a very useful tool. Depending upon the limitations of the relevant data available benefit-cost analysis can offer information to society about how to improve its condition. However, beyond the criticism of its estimate of the Pareto optimal point benefit-cost analysis suffers from a fundamental weakness: It cannot speak to the distribution of the net benefits of implementation of an international greenhouse policy. Within an individual country, debate on a particular policy intervention can effectively separate the issues of achieving a potential Pareto optimum and distributing the benefits necessary to actually accomplish Pareto optimality. This situation occurs because (theoretically, anyway) these decisions are made in the presence of a binding enforcement regime that can redistribute benefits as seen fit. A policy can then be introduced in the manner that achieves the best overall net benefits, and the allocation of these benefits can be treated as a stand-alone problem

Analysis of employee benefits in Factoring KB, a.s.v

OpenAIRE

Vachoušek, Stanislav

2011-01-01

The main objective of this work is to analyze employee benefits - benefits of Factoring KB, a.s. The theoretical part of the generally specifies the basic concepts related to employee benefits needed to cope with the analytical part. The content of this section is primarily a system of employee benefits, classification of employee benefits, tax savings and marginally trends in providing benefits. The analytical part is devoted exclusively to Factoring KB, there is an analysis of employee bene...

Cost-benefit analysis for management of low-level radioactive waste

International Nuclear Information System (INIS)

Jacobs, D.G.

1979-01-01

There are several types of cost-benefit analyses that can be used in evaluating a technical activity such as waste management. A direct comparison can be made of the benefits to be gained versus the costs to be accrued. If the balance is favorable the activity is considered to be acceptable. In many cases, however, a number of alternatives may be available requiring a comparative cost-benefit analysis so that the most favorable option is chosen. After the basic option is chosen, a further analysis is required in which additional control technologies can be considered to further reduce specific types of impact; this represents a differential cost-benefit analysis or, perhaps more properly, a study of cost-effectiveness. Also, because of the wide variety of parameters that go into a cost-benefit analysis and the range of value judgements that may be applied by different interest groups, it is likely that each additional increment of technology will have a slightly different balance point. Factors and impacts that need to be considered in management of low-level wastes will be discussed and a simplified example will be used to demonstrate the difficulties that may be encountered

Cost-benefit analysis for management of low-level radioactive waste

International Nuclear Information System (INIS)

Jacobs, D.G.

1977-01-01

There are several types of cost-benefit analyses that can be used in evaluating a technical activity such as waste management. A direct comparison can be made of the benefits to be gained versus the costs to be accrued. If the balance is favorable, the activity is considered to be acceptable. In many cases, however, a number of alternatives may be available requiring a comparative cost-benefit analysis so that the most favorable option is chosen. After the basic option is chosen, a further analysis is required in which additional control technologies can be considered to further reduce specific types of impact; this represents a differential cost-benefit analysis or, perhaps more properly, a study of cost-effectiveness. Also, because of the wide variety of parameters that go into a cost-benefit analysis and the range of value judgements that may be applied by different interest groups, it is likely that each additional increment of technology will have a slightly different balance point. Factors and impacts that need to be considered in management of low-level wastes will be discussed and a simplified example will be used to demonstrate the difficulties that may be encountered

A Benefit Analysis of Infusing Wireless into Aircraft and Fleet Operations - Report to Seedling Project Efficient Reconfigurable Cockpit Design and Fleet Operations Using Software Intensive, Network Enabled, Wireless Architecture (ECON)

Science.gov (United States)

Alexandrov, Natalia; Holmes, Bruce J.; Hahn, Andrew S.

2016-01-01

We report on an examination of potential benefits of infusing wireless technologies into various areas of aircraft and airspace operations. The analysis is done in support of a NASA seedling project Efficient Reconfigurable Cockpit Design and Fleet Operations Using Software Intensive, Network Enabled Wireless Architecture (ECON). The study has two objectives. First, we investigate one of the main benefit hypotheses of the ECON proposal: that the replacement of wired technologies with wireless would lead to significant weight reductions on an aircraft, among other benefits. Second, we advance a list of wireless technology applications and discuss their system benefits. With regard to the primary hypothesis, we conclude that the promise of weight reduction is premature. Specificity of the system domain and aircraft, criticality of components, reliability of wireless technologies, the weight of replacement or augmentation equipment, and the cost of infusion must all be taken into account among other considerations, to produce a reliable estimate of weight savings or increase.

Reliability Analysis of Operation for Cableways by FTA (Fault Tree Analysis Method

Directory of Open Access Journals (Sweden)

Sergej Težak

2010-05-01

Full Text Available This paper examines the reliability of the operation of cableway systems in Slovenia, which has major impact on the quality of service in the mountain tourism, mainly in wintertime. Different types of cableway installations in Slovenia were captured in a sample and fault tree analysis (FTA was made on the basis of the obtained data. The paper presents the results of the analysis. With these results it is possible to determine the probability of faults of different types of cableways, which types of faults have the greatest impact on the termination of operation, which components of cableways fail most, what is the impact of age of cableways on the occurrence of the faults. Finally, an attempt was made to find if occurrence of faults on individual cableway installation has also impact on traffic on this cableway due to reduced quality of service. KEYWORDS: cableways, aerial ropeways, chairlifts, ski-tows, quality, faults, fault tree analysis, reliability, service quality, winter tourism, mountain tourist centre

Cost-Benefit Analysis of Smart Grids Implementation

International Nuclear Information System (INIS)

Tomsic, Z.; Pongrasic, M.

2014-01-01

Paper presents guidelines for conducting the cost-benefit analysis of Smart Grid projects connected to the implementation of advanced technologies in electric power system. Restrictions of presented electric power networks are also mentioned along with solutions that are offered by advanced electric power network. From an economic point of view, the main characteristic of advanced electric power network is big investment, and benefits are seen after some time with risk of being smaller than expected. Therefore it is important to make a comprehensive analysis of those projects which consist of economic and qualitative analysis. This report relies on EPRI methodology developed in American institute for energy. The methodology is comprehensive and useful, but also simple and easy to understand. Steps of this methodology and main characteristics of methodologies which refer to EPRI methodology: methodology developed in Joint Research Center and methodologies for analysing implementation of smart meters in electricity power network are explained. Costs, benefits and categories in which they can be classified are also defined. As a part of qualitative analysis, social aspect of Smart Grid projects is described. In cost defining, special attention has to be paid to projects of integrating electricity from variable renewable energy sources into the power system because of additional costs. This work summarized categories of additional costs. In the end of this report, an overview is given of what has been done and what will be done in European Union. (author).

Reliability Analysis Of Fire System On The Industry Facility By Use Fameca Method

International Nuclear Information System (INIS)

Sony T, D.T.; Situmorang, Johnny; Ismu W, Puradwi; Demon H; Mulyanto, Dwijo; Kusmono, Slamet; Santa, Sigit Asmara

2000-01-01

FAMECA is one of the analysis method to determine system reliability on the industry facility. Analysis is done by some procedure that is identification of component function, determination of failure mode, severity level and effect of their failure. Reliability value is determined by three combinations that is severity level, component failure value and critical component. Reliability of analysis has been done for fire system on the industry by FAMECA method. Critical component which identified is pump, air release valve, check valve, manual test valve, isolation valve, control system etc

Cost benefit analysis of reactor safety systems

International Nuclear Information System (INIS)

Maurer, H.A.

1984-01-01

Cost/benefit analysis of reactor safety systems is a possibility appropriate to deal with reactor safety. The Commission of the European Communities supported a study on the cost-benefit or cost effectiveness of safety systems installed in modern PWR nuclear power plants. The following systems and their cooperation in emergency cases were in particular investigated in this study: the containment system (double containment), the leakage exhaust and control system, the annulus release exhaust system and the containment spray system. The benefit of a safety system is defined according to its contribution to the reduction of the radiological consequences for the environment after a LOCA. The analysis is so far performed in two different steps: the emergency core cooling system is considered to function properly, failure of the emergency core cooling system is assumed (with the possible consequence of core melt-down) and the results may demonstrate the evidence that striving for cost-effectiveness can produce a safer end result than the philosophy of safety at any cost. (orig.)

The quantitative failure of human reliability analysis

Energy Technology Data Exchange (ETDEWEB)

Bennett, C.T.

1995-07-01

This philosophical treatise argues the merits of Human Reliability Analysis (HRA) in the context of the nuclear power industry. Actually, the author attacks historic and current HRA as having failed in informing policy makers who make decisions based on risk that humans contribute to systems performance. He argues for an HRA based on Bayesian (fact-based) inferential statistics, which advocates a systems analysis process that employs cogent heuristics when using opinion, and tempers itself with a rational debate over the weight given subjective and empirical probabilities.

Reliability analysis of HVDC grid combined with power flow simulations

Energy Technology Data Exchange (ETDEWEB)

Yang, Yongtao; Langeland, Tore; Solvik, Johan [DNV AS, Hoevik (Norway); Stewart, Emma [DNV KEMA, Camino Ramon, CA (United States)

2012-07-01

Based on a DC grid power flow solver and the proposed GEIR, we carried out reliability analysis for a HVDC grid test system proposed by CIGRE working group B4-58, where the failure statistics are collected from literature survey. The proposed methodology is used to evaluate the impact of converter configuration on the overall reliability performance of the HVDC grid, where the symmetrical monopole configuration is compared with the bipole with metallic return wire configuration. The results quantify the improvement on reliability by using the later alternative. (orig.)

Reliability analysis of neutron transport simulation using Monte Carlo method

International Nuclear Information System (INIS)

Souza, Bismarck A. de; Borges, Jose C.

1995-01-01

This work presents a statistical and reliability analysis covering data obtained by computer simulation of neutron transport process, using the Monte Carlo method. A general description of the method and its applications is presented. Several simulations, corresponding to slowing down and shielding problems have been accomplished. The influence of the physical dimensions of the materials and of the sample size on the reliability level of results was investigated. The objective was to optimize the sample size, in order to obtain reliable results, optimizing computation time. (author). 5 refs, 8 figs

An exact method for solving logical loops in reliability analysis

International Nuclear Information System (INIS)

Matsuoka, Takeshi

2009-01-01

This paper presents an exact method for solving logical loops in reliability analysis. The systems that include logical loops are usually described by simultaneous Boolean equations. First, present a basic rule of solving simultaneous Boolean equations. Next, show the analysis procedures for three-component system with external supports. Third, more detailed discussions are given for the establishment of logical loop relation. Finally, take up two typical structures which include more than one logical loop. Their analysis results and corresponding GO-FLOW charts are given. The proposed analytical method is applicable to loop structures that can be described by simultaneous Boolean equations, and it is very useful in evaluating the reliability of complex engineering systems.

Damage tolerance reliability analysis of automotive spot-welded joints

International Nuclear Information System (INIS)

Mahadevan, Sankaran; Ni Kan

2003-01-01

This paper develops a damage tolerance reliability analysis methodology for automotive spot-welded joints under multi-axial and variable amplitude loading history. The total fatigue life of a spot weld is divided into two parts, crack initiation and crack propagation. The multi-axial loading history is obtained from transient response finite element analysis of a vehicle model. A three-dimensional finite element model of a simplified joint with four spot welds is developed for static stress/strain analysis. A probabilistic Miner's rule is combined with a randomized strain-life curve family and the stress/strain analysis result to develop a strain-based probabilistic fatigue crack initiation life prediction for spot welds. Afterwards, the fatigue crack inside the base material sheet is modeled as a surface crack. Then a probabilistic crack growth model is combined with the stress analysis result to develop a probabilistic fatigue crack growth life prediction for spot welds. Both methods are implemented with MSC/NASTRAN and MSC/FATIGUE software, and are useful for reliability assessment of automotive spot-welded joints against fatigue and fracture

Optimization Of Methodological Support Of Application Tax Benefits In Regions: Practice Of Perm Region

Directory of Open Access Journals (Sweden)

Alexandr Ivanovich Tatarkin

2015-03-01

Full Text Available In the article, the problem of the methodological process support of regional tax benefits is reviewed. The method of tax benefits assessment, accepted in Perm Region, was chosen as an analysis object because the relatively long period of application of benefits has allowed to build enough statistics base. In the article, the reliability of budget, economic, investment, and social effectiveness assessments of application benefits, based on the Method, is investigated. The suggestions of its perfection are formulated

Probabilistic analysis of modernization options

International Nuclear Information System (INIS)

Wunderlich, W.O.; Giles, J.E.

1991-01-01

This paper reports on benefit-cost analysis for hydropower operations, a standard procedure for reaching planning decisions. Cost overruns and benefit shortfalls are also common occurrences. One reason for the difficulty of predicting future benefits and costs is that they usually cannot be represented with sufficient reliability by accurate values, because of the many uncertainties that enter the analysis through assumptions on inputs and system parameters. Therefore, ranges of variables need to be analyzed instead of single values. As a consequence, the decision criteria, such as net benefit and benefit-cost ratio, also vary over some range. A probabilistic approach will be demonstrated as a tool for assessing the reliability of the results

Development and application of a cost-benefit framework for energy reliability. Using probabilistic methods in network planning and regulation to enhance social welfare. The N-1 rule

International Nuclear Information System (INIS)

Nooij, Michiel de; Baarsma, Barbara; Bloemhof, Gabriel; Dijk, Harold; Slootweg, Han

2010-01-01

Although electricity is crucial to many activities in developed societies, guaranteeing a maximum reliability of supply to end-users is extremely costly. This situation gives rise to a trade-off between the costs and benefits of reliability. The Dutch government has responded to this trade-off by changing the rule stipulating that electricity networks must be able to maintain supply even if one component fails (known as the N-1 rule), even in maintenance situations. This rule was changed by adding the phrase 'unless the costs exceed the benefits.' We have developed a cost-benefit framework for the implementation and application of this new rule. The framework requires input on failure probability, the cost of supply interruptions to end-users and the cost of investments. A case study of the Dutch grid shows that the method is indeed practicable and that it is highly unlikely that N-1 during maintenance will enhance welfare in the Netherlands. Therefore, including the limitation 'unless the costs exceed the benefits' in the rule has been a sensible policy for the Netherlands, and would also be a sensible policy for other countries. (author)

Applying reliability analysis to design electric power systems for More-electric aircraft

Science.gov (United States)

Zhang, Baozhu

The More-Electric Aircraft (MEA) is a type of aircraft that replaces conventional hydraulic and pneumatic systems with electrically powered components. These changes have significantly challenged the aircraft electric power system design. This thesis investigates how reliability analysis can be applied to automatically generate system topologies for the MEA electric power system. We first use a traditional method of reliability block diagrams to analyze the reliability level on different system topologies. We next propose a new methodology in which system topologies, constrained by a set reliability level, are automatically generated. The path-set method is used for analysis. Finally, we interface these sets of system topologies with control synthesis tools to automatically create correct-by-construction control logic for the electric power system.

Reliability of three-dimensional gait analysis in cervical spondylotic myelopathy.

LENUS (Irish Health Repository)

McDermott, Ailish

2010-10-01

Gait impairment is one of the primary symptoms of cervical spondylotic myelopathy (CSM). Detailed assessment is possible using three-dimensional gait analysis (3DGA), however the reliability of 3DGA for this population has not been established. The aim of this study was to evaluate the test-retest reliability of temporal-spatial, kinematic and kinetic parameters in a CSM population.

Reliability Calculations

DEFF Research Database (Denmark)

Petersen, Kurt Erling

1986-01-01

Risk and reliability analysis is increasingly being used in evaluations of plant safety and plant reliability. The analysis can be performed either during the design process or during the operation time, with the purpose to improve the safety or the reliability. Due to plant complexity and safety...... and availability requirements, sophisticated tools, which are flexible and efficient, are needed. Such tools have been developed in the last 20 years and they have to be continuously refined to meet the growing requirements. Two different areas of application were analysed. In structural reliability probabilistic...... approaches have been introduced in some cases for the calculation of the reliability of structures or components. A new computer program has been developed based upon numerical integration in several variables. In systems reliability Monte Carlo simulation programs are used especially in analysis of very...

Hybrid Structural Reliability Analysis under Multisource Uncertainties Based on Universal Grey Numbers

Directory of Open Access Journals (Sweden)

Xingfa Yang

2018-01-01

Full Text Available Nondeterministic parameters of certain distribution are employed to model structural uncertainties, which are usually assumed as stochastic factors. However, model parameters may not be precisely represented due to some factors in engineering practices, such as lack of sufficient data, data with fuzziness, and unknown-but-bounded conditions. To this end, interval and fuzzy parameters are implemented and an efficient approach to structural reliability analysis with random-interval-fuzzy hybrid parameters is proposed in this study. Fuzzy parameters are first converted to equivalent random ones based on the equal entropy principle. 3σ criterion is then employed to transform the equivalent random and the original random parameters to interval variables. In doing this, the hybrid reliability problem is transformed into the one only with interval variables, in other words, nonprobabilistic reliability analysis problem. Nevertheless, the problem of interval extension existed in interval arithmetic, especially for the nonlinear systems. Therefore, universal grey mathematics, which can tackle the issue of interval extension, is employed to solve the nonprobabilistic reliability analysis problem. The results show that the proposed method can obtain more conservative results of the hybrid structural reliability.

Inclusion of task dependence in human reliability analysis

International Nuclear Information System (INIS)

Su, Xiaoyan; Mahadevan, Sankaran; Xu, Peida; Deng, Yong

2014-01-01

Dependence assessment among human errors in human reliability analysis (HRA) is an important issue, which includes the evaluation of the dependence among human tasks and the effect of the dependence on the final human error probability (HEP). This paper represents a computational model to handle dependence in human reliability analysis. The aim of the study is to automatically provide conclusions on the overall degree of dependence and calculate the conditional human error probability (CHEP) once the judgments of the input factors are given. The dependence influencing factors are first identified by the experts and the priorities of these factors are also taken into consideration. Anchors and qualitative labels are provided as guidance for the HRA analyst's judgment of the input factors. The overall degree of dependence between human failure events is calculated based on the input values and the weights of the input factors. Finally, the CHEP is obtained according to a computing formula derived from the technique for human error rate prediction (THERP) method. The proposed method is able to quantify the subjective judgment from the experts and improve the transparency in the HEP evaluation process. Two examples are illustrated to show the effectiveness and the flexibility of the proposed method. - Highlights: • We propose a computational model to handle dependence in human reliability analysis. • The priorities of the dependence influencing factors are taken into consideration. • The overall dependence degree is determined by input judgments and the weights of factors. • The CHEP is obtained according to a computing formula derived from THERP

Infusing Reliability Techniques into Software Safety Analysis

Science.gov (United States)

Shi, Ying

2015-01-01

Software safety analysis for a large software intensive system is always a challenge. Software safety practitioners need to ensure that software related hazards are completely identified, controlled, and tracked. This paper discusses in detail how to incorporate the traditional reliability techniques into the entire software safety analysis process. In addition, this paper addresses how information can be effectively shared between the various practitioners involved in the software safety analyses. The author has successfully applied the approach to several aerospace applications. Examples are provided to illustrate the key steps of the proposed approach.

Medicares Hospice Benefit - Analysis of Utilization and..

Data.gov (United States)

U.S. Department of Health & Human Services — Descriptive analyses reported in Medicares Hospice Benefit - Analysis of Utilization and Resource Use, published in Volume 4, Issue 3 of the Medicare and Medicaid...

Multidisciplinary Inverse Reliability Analysis Based on Collaborative Optimization with Combination of Linear Approximations

Directory of Open Access Journals (Sweden)

Xin-Jia Meng

2015-01-01

Full Text Available Multidisciplinary reliability is an important part of the reliability-based multidisciplinary design optimization (RBMDO. However, it usually has a considerable amount of calculation. The purpose of this paper is to improve the computational efficiency of multidisciplinary inverse reliability analysis. A multidisciplinary inverse reliability analysis method based on collaborative optimization with combination of linear approximations (CLA-CO is proposed in this paper. In the proposed method, the multidisciplinary reliability assessment problem is first transformed into a problem of most probable failure point (MPP search of inverse reliability, and then the process of searching for MPP of multidisciplinary inverse reliability is performed based on the framework of CLA-CO. This method improves the MPP searching process through two elements. One is treating the discipline analyses as the equality constraints in the subsystem optimization, and the other is using linear approximations corresponding to subsystem responses as the replacement of the consistency equality constraint in system optimization. With these two elements, the proposed method realizes the parallel analysis of each discipline, and it also has a higher computational efficiency. Additionally, there are no difficulties in applying the proposed method to problems with nonnormal distribution variables. One mathematical test problem and an electronic packaging problem are used to demonstrate the effectiveness of the proposed method.

Reliability test and failure analysis of high power LED packages

International Nuclear Information System (INIS)

Chen Zhaohui; Zhang Qin; Wang Kai; Luo Xiaobing; Liu Sheng

2011-01-01

A new type application specific light emitting diode (LED) package (ASLP) with freeform polycarbonate lens for street lighting is developed, whose manufacturing processes are compatible with a typical LED packaging process. The reliability test methods and failure criterions from different vendors are reviewed and compared. It is found that test methods and failure criterions are quite different. The rapid reliability assessment standards are urgently needed for the LED industry. 85 0 C/85 RH with 700 mA is used to test our LED modules with three other vendors for 1000 h, showing no visible degradation in optical performance for our modules, with two other vendors showing significant degradation. Some failure analysis methods such as C-SAM, Nano X-ray CT and optical microscope are used for LED packages. Some failure mechanisms such as delaminations and cracks are detected in the LED packages after the accelerated reliability testing. The finite element simulation method is helpful for the failure analysis and design of the reliability of the LED packaging. One example is used to show one currently used module in industry is vulnerable and may not easily pass the harsh thermal cycle testing. (semiconductor devices)

Environmentally based Cost-Benefit Analysis

International Nuclear Information System (INIS)

Magnell, M.

1993-11-01

The fundamentals of the basic elements of a new comprehensive economic assessment, MILA, developed in Sweden with inspiration from the Total Cost Assessment-model are presented. The core of the MILA approach is an expanded cost and benefit inventory. But MILA also includes a complementary addition of an internal waste stream analysis, a tool for evaluation of environmental conflicts in monetary terms, an extended time horizon and direct allocation of costs and revenues to products and processes. However, MILA does not ensure profitability for environmentally sound projects. Essentially, MILA is an approach of refining investment and profitability analysis of a project, investment or product. 109 refs., 38 figs

Reliability analysis based on the losses from failures.

Science.gov (United States)

Todinov, M T

2006-04-01

The conventional reliability analysis is based on the premise that increasing the reliability of a system will decrease the losses from failures. On the basis of counterexamples, it is demonstrated that this is valid only if all failures are associated with the same losses. In case of failures associated with different losses, a system with larger reliability is not necessarily characterized by smaller losses from failures. Consequently, a theoretical framework and models are proposed for a reliability analysis, linking reliability and the losses from failures. Equations related to the distributions of the potential losses from failure have been derived. It is argued that the classical risk equation only estimates the average value of the potential losses from failure and does not provide insight into the variability associated with the potential losses. Equations have also been derived for determining the potential and the expected losses from failures for nonrepairable and repairable systems with components arranged in series, with arbitrary life distributions. The equations are also valid for systems/components with multiple mutually exclusive failure modes. The expected losses given failure is a linear combination of the expected losses from failure associated with the separate failure modes scaled by the conditional probabilities with which the failure modes initiate failure. On this basis, an efficient method for simplifying complex reliability block diagrams has been developed. Branches of components arranged in series whose failures are mutually exclusive can be reduced to single components with equivalent hazard rate, downtime, and expected costs associated with intervention and repair. A model for estimating the expected losses from early-life failures has also been developed. For a specified time interval, the expected losses from early-life failures are a sum of the products of the expected number of failures in the specified time intervals covering the

Johnson Space Center's Risk and Reliability Analysis Group 2008 Annual Report

Science.gov (United States)

Valentine, Mark; Boyer, Roger; Cross, Bob; Hamlin, Teri; Roelant, Henk; Stewart, Mike; Bigler, Mark; Winter, Scott; Reistle, Bruce; Heydorn,Dick

2009-01-01

The Johnson Space Center (JSC) Safety & Mission Assurance (S&MA) Directorate s Risk and Reliability Analysis Group provides both mathematical and engineering analysis expertise in the areas of Probabilistic Risk Assessment (PRA), Reliability and Maintainability (R&M) analysis, and data collection and analysis. The fundamental goal of this group is to provide National Aeronautics and Space Administration (NASA) decisionmakers with the necessary information to make informed decisions when evaluating personnel, flight hardware, and public safety concerns associated with current operating systems as well as with any future systems. The Analysis Group includes a staff of statistical and reliability experts with valuable backgrounds in the statistical, reliability, and engineering fields. This group includes JSC S&MA Analysis Branch personnel as well as S&MA support services contractors, such as Science Applications International Corporation (SAIC) and SoHaR. The Analysis Group s experience base includes nuclear power (both commercial and navy), manufacturing, Department of Defense, chemical, and shipping industries, as well as significant aerospace experience specifically in the Shuttle, International Space Station (ISS), and Constellation Programs. The Analysis Group partners with project and program offices, other NASA centers, NASA contractors, and universities to provide additional resources or information to the group when performing various analysis tasks. The JSC S&MA Analysis Group is recognized as a leader in risk and reliability analysis within the NASA community. Therefore, the Analysis Group is in high demand to help the Space Shuttle Program (SSP) continue to fly safely, assist in designing the next generation spacecraft for the Constellation Program (CxP), and promote advanced analytical techniques. The Analysis Section s tasks include teaching classes and instituting personnel qualification processes to enhance the professional abilities of our analysts

Analysis of NPP protection structure reliability under impact of a falling aircraft

International Nuclear Information System (INIS)

Shul'man, G.S.

1996-01-01

Methodology for evaluation of NPP protection structure reliability by impact of aircraft fall down is considered. The methodology is base on the probabilistic analysis of all potential events. The problem is solved in three stages: determination of loads on structural units, calculation of local reliability of protection structures by assigned loads and estimation of the structure reliability. The methodology proposed may be applied at the NPP design stage and by determination of reliability of already available structures

Economic impact analysis for global warming: Sensitivity analysis for cost and benefit estimates

International Nuclear Information System (INIS)

Ierland, E.C. van; Derksen, L.

1994-01-01

Proper policies for the prevention or mitigation of the effects of global warming require profound analysis of the costs and benefits of alternative policy strategies. Given the uncertainty about the scientific aspects of the process of global warming, in this paper a sensitivity analysis for the impact of various estimates of costs and benefits of greenhouse gas reduction strategies is carried out to analyze the potential social and economic impacts of climate change

Reliability Analysis of Retaining Walls Subjected to Blast Loading by Finite Element Approach

Science.gov (United States)

GuhaRay, Anasua; Mondal, Stuti; Mohiuddin, Hisham Hasan

2018-02-01

Conventional design methods adopt factor of safety as per practice and experience, which are deterministic in nature. The limit state method, though not completely deterministic, does not take into account effect of design parameters, which are inherently variable such as cohesion, angle of internal friction, etc. for soil. Reliability analysis provides a measure to consider these variations into analysis and hence results in a more realistic design. Several studies have been carried out on reliability of reinforced concrete walls and masonry walls under explosions. Also, reliability analysis of retaining structures against various kinds of failure has been done. However, very few research works are available on reliability analysis of retaining walls subjected to blast loading. Thus, the present paper considers the effect of variation of geotechnical parameters when a retaining wall is subjected to blast loading. However, it is found that the variation of geotechnical random variables does not have a significant effect on the stability of retaining walls subjected to blast loading.

Space solar array reliability: A study and recommendations

Science.gov (United States)

Brandhorst, Henry W., Jr.; Rodiek, Julie A.

2008-12-01

Providing reliable power over the anticipated mission life is critical to all satellites; therefore solar arrays are one of the most vital links to satellite mission success. Furthermore, solar arrays are exposed to the harshest environment of virtually any satellite component. In the past 10 years 117 satellite solar array anomalies have been recorded with 12 resulting in total satellite failure. Through an in-depth analysis of satellite anomalies listed in the Airclaim's Ascend SpaceTrak database, it is clear that solar array reliability is a serious, industry-wide issue. Solar array reliability directly affects the cost of future satellites through increased insurance premiums and a lack of confidence by investors. Recommendations for improving reliability through careful ground testing, standardization of testing procedures such as the emerging AIAA standards, and data sharing across the industry will be discussed. The benefits of creating a certified module and array testing facility that would certify in-space reliability will also be briefly examined. Solar array reliability is an issue that must be addressed to both reduce costs and ensure continued viability of the commercial and government assets on orbit.

Reliability Engineering

International Nuclear Information System (INIS)

Lee, Sang Yong

1992-07-01

This book is about reliability engineering, which describes definition and importance of reliability, development of reliability engineering, failure rate and failure probability density function about types of it, CFR and index distribution, IFR and normal distribution and Weibull distribution, maintainability and movability, reliability test and reliability assumption in index distribution type, normal distribution type and Weibull distribution type, reliability sampling test, reliability of system, design of reliability and functionality failure analysis by FTA.

Decision theory, the context for risk and reliability analysis

International Nuclear Information System (INIS)

Kaplan, S.

1985-01-01

According to this model of the decision process then, the optimum decision is that option having the largest expected utility. This is the fundamental model of a decision situation. It is necessary to remark that in order for the model to represent a real-life decision situation, it must include all the options present in that situation, including, for example, the option of not deciding--which is itself a decision, although usually not the optimum one. Similarly, it should include the option of delaying the decision while the authors gather further information. Both of these options have probabilities, outcomes, impacts, and utilities like any option and should be included explicitly in the decision diagram. The reason for doing a quantitative risk or reliability analysis is always that, somewhere underlying there is a decision to be made. The decision analysis therefore always forms the context for the risk or reliability analysis, and this context shapes the form and language of that analysis. Therefore, they give in this section a brief review of the well-known decision theory diagram

Inclusion of fatigue effects in human reliability analysis

Energy Technology Data Exchange (ETDEWEB)

Griffith, Candice D. [Vanderbilt University, Nashville, TN (United States); Mahadevan, Sankaran, E-mail: sankaran.mahadevan@vanderbilt.edu [Vanderbilt University, Nashville, TN (United States)

2011-11-15

The effect of fatigue on human performance has been observed to be an important factor in many industrial accidents. However, defining and measuring fatigue is not easily accomplished. This creates difficulties in including fatigue effects in probabilistic risk assessments (PRA) of complex engineering systems that seek to include human reliability analysis (HRA). Thus the objectives of this paper are to discuss (1) the importance of the effects of fatigue on performance, (2) the difficulties associated with defining and measuring fatigue, (3) the current status of inclusion of fatigue in HRA methods, and (4) the future directions and challenges for the inclusion of fatigue, specifically sleep deprivation, in HRA. - Highlights: >We highlight the need for fatigue and sleep deprivation effects on performance to be included in human reliability analysis (HRA) methods. Current methods do not explicitly include sleep deprivation effects. > We discuss the difficulties in defining and measuring fatigue. > We review sleep deprivation research, and discuss the limitations and future needs of the current HRA methods.

Modeling of seismic hazards for dynamic reliability analysis

International Nuclear Information System (INIS)

Mizutani, M.; Fukushima, S.; Akao, Y.; Katukura, H.

1993-01-01

This paper investigates the appropriate indices of seismic hazard curves (SHCs) for seismic reliability analysis. In the most seismic reliability analyses of structures, the seismic hazards are defined in the form of the SHCs of peak ground accelerations (PGAs). Usually PGAs play a significant role in characterizing ground motions. However, PGA is not always a suitable index of seismic motions. When random vibration theory developed in the frequency domain is employed to obtain statistics of responses, it is more convenient for the implementation of dynamic reliability analysis (DRA) to utilize an index which can be determined in the frequency domain. In this paper, we summarize relationships among the indices which characterize ground motions. The relationships between the indices and the magnitude M are arranged as well. In this consideration, duration time plays an important role in relating two distinct class, i.e. energy class and power class. Fourier and energy spectra are involved in the energy class, and power and response spectra and PGAs are involved in the power class. These relationships are also investigated by using ground motion records. Through these investigations, we have shown the efficiency of employing the total energy as an index of SHCs, which can be determined in the time and frequency domains and has less variance than the other indices. In addition, we have proposed the procedure of DRA based on total energy. (author)

A Benefit-Risk Analysis Approach to Capture Regulatory Decision-Making: Multiple Myeloma.

Science.gov (United States)

Raju, G K; Gurumurthi, Karthik; Domike, Reuben; Kazandjian, Dickran; Landgren, Ola; Blumenthal, Gideon M; Farrell, Ann; Pazdur, Richard; Woodcock, Janet

2018-01-01

Drug regulators around the world make decisions about drug approvability based on qualitative benefit-risk analysis. In this work, a quantitative benefit-risk analysis approach captures regulatory decision-making about new drugs to treat multiple myeloma (MM). MM assessments have been based on endpoints such as time to progression (TTP), progression-free survival (PFS), and objective response rate (ORR) which are different than benefit-risk analysis based on overall survival (OS). Twenty-three FDA decisions on MM drugs submitted to FDA between 2003 and 2016 were identified and analyzed. The benefits and risks were quantified relative to comparators (typically the control arm of the clinical trial) to estimate whether the median benefit-risk was positive or negative. A sensitivity analysis was demonstrated using ixazomib to explore the magnitude of uncertainty. FDA approval decision outcomes were consistent and logical using this benefit-risk framework. © 2017 American Society for Clinical Pharmacology and Therapeutics.

The Monte Carlo Simulation Method for System Reliability and Risk Analysis

CERN Document Server

Zio, Enrico

2013-01-01

Monte Carlo simulation is one of the best tools for performing realistic analysis of complex systems as it allows most of the limiting assumptions on system behavior to be relaxed. The Monte Carlo Simulation Method for System Reliability and Risk Analysis comprehensively illustrates the Monte Carlo simulation method and its application to reliability and system engineering. Readers are given a sound understanding of the fundamentals of Monte Carlo sampling and simulation and its application for realistic system modeling.   Whilst many of the topics rely on a high-level understanding of calculus, probability and statistics, simple academic examples will be provided in support to the explanation of the theoretical foundations to facilitate comprehension of the subject matter. Case studies will be introduced to provide the practical value of the most advanced techniques.   This detailed approach makes The Monte Carlo Simulation Method for System Reliability and Risk Analysis a key reference for senior undergra...

Summary of component reliability data for probabilistic safety analysis of Korean standard nuclear power plant

International Nuclear Information System (INIS)

Choi, S. Y.; Han, S. H.

2004-01-01

The reliability data of Korean NPP that reflects the plant specific characteristics is necessary for PSA of Korean nuclear power plants. We have performed a study to develop the component reliability DB and S/W for component reliability analysis. Based on the system, we had have collected the component operation data and failure/repair data during plant operation data to 1998/2000 for YGN 3,4/UCN 3,4 respectively. Recently, we have upgraded the database by collecting additional data by 2002 for Korean standard nuclear power plants and performed component reliability analysis and Bayesian analysis again. In this paper, we supply the summary of component reliability data for probabilistic safety analysis of Korean standard nuclear power plant and describe the plant specific characteristics compared to the generic data

Benefit/risk analysis of cardiac pacemakers powered by Betacel 147Pm batteries

International Nuclear Information System (INIS)

Smith, T.H.; Greenborg, J.; Matheson, W.E.

1975-01-01

Cardiac pacemakers powered by Betacel 147 Pm nuclear batteries are undergoing clinical evaluation in Europe and the United States. This benefit/risk study analyzes the potential effects from unrestricted use of 20,000 pacemakers powered by these betavoltaic batteries. The beneficial effects of this device (lives saved and reduced medical expenses) result from improved reliability and operating lifetime (approximately 9 yr) compared with widely available chemical batteries of substantially shorter life (approximately 2 1 / 2 yr). Calculated benefits are $16,800,000/yr savings to society and 76 lives (approximately 800 life-years) saved per year. Risks to the patient and the general population are generally less than those from natural accidents such as landslides and lightning strikes. The calculated benefit/risk ratios of 180 in terms of lives and 440 in monetary terms are in the range commonly accepted by the public. (U.S.)

State of the art in benefit-risk analysis: introduction.

Science.gov (United States)

Verhagen, H; Tijhuis, M J; Gunnlaugsdóttir, H; Kalogeras, N; Leino, O; Luteijn, J M; Magnússon, S H; Odekerken, G; Pohjola, M V; Tuomisto, J T; Ueland, Ø; White, B C; Holm, F

2012-01-01

Risk-taking is normal in everyday life if there are associated (perceived) benefits. Benefit-Risk Analysis (BRA) compares the risk of a situation to its related benefits and addresses the acceptability of the risk. Over the past years BRA in relation to food and food ingredients has gained attention. Food, and even the same food ingredient, may confer both beneficial and adverse effects. Measures directed at food safety may lead to suboptimal or insufficient levels of ingredients from a benefit perspective. In BRA, benefits and risks of food (ingredients) are assessed in one go and may conditionally be expressed into one currency. This allows the comparison of adverse and beneficial effects to be qualitative and quantitative. A BRA should help policy-makers to make more informed and balanced benefit-risk management decisions. Not allowing food benefits to occur in order to guarantee food safety is a risk management decision much the same as accepting some risk in order to achieve more benefits. BRA in food and nutrition is making progress, but difficulties remain. The field may benefit from looking across its borders to learn from other research areas. The BEPRARIBEAN project (Best Practices for Risk-Benefit Analysis: experience from out of food into food; http://en.opasnet.org/w/Bepraribean) aims to do so, by working together with Medicines, Food Microbiology, Environmental Health, Economics & Marketing-Finance and Consumer Perception. All perspectives are reviewed and subsequently integrated to identify opportunities for further development of BRA for food and food ingredients. Interesting issues that emerge are the varying degrees of risk that are deemed acceptable within the areas and the trend towards more open and participatory BRA processes. A set of 6 'state of the art' papers covering the above areas and a paper integrating the separate (re)views are published in this volume. Copyright © 2011 Elsevier Ltd. All rights reserved.

reliability analysis of a two span floor designed according

African Journals Online (AJOL)

user

deterministic approach, considering both ultimate and serviceability limit states. Reliability analysis of the floor ... loading, strength and stiffness parameters, dimensions .... to show that there is a direct relation between the failure probability (Pf) ...

New values of time and reliability in passenger transport in the Netherlands

NARCIS (Netherlands)

Kouwenhoven, M.; de Jong, G.; Koster, P.R.; van den Berg, V.A.C.; Verhoef, E.T.; Bates, J.; Warffemius, P.

2014-01-01

We have established new values of time (VOTs) and values of travel time reliability (VORs) for use in cost-benefit analysis (CBA) of transport projects in The Netherlands. This was the first national study in The Netherlands (and one of the first world-wide) to investigate these topics empirically

Reliability analysis and updating of deteriorating systems with subset simulation

DEFF Research Database (Denmark)

Schneider, Ronald; Thöns, Sebastian; Straub, Daniel

2017-01-01

An efficient approach to reliability analysis of deteriorating structural systems is presented, which considers stochastic dependence among element deterioration. Information on a deteriorating structure obtained through inspection or monitoring is included in the reliability assessment through B...... is an efficient and robust sampling-based algorithm suitable for such analyses. The approach is demonstrated in two case studies considering a steel frame structure and a Daniels system subjected to high-cycle fatigue....

Use of COMCAN III in system design and reliability analysis

International Nuclear Information System (INIS)

Rasmuson, D.M.; Shepherd, J.C.; Marshall, N.H.; Fitch, L.R.

1982-03-01

This manual describes the COMCAN III computer program and its use. COMCAN III is a tool that can be used by the reliability analyst performing a probabilistic risk assessment or by the designer of a system desiring improved performance and efficiency. COMCAN III can be used to determine minimal cut sets of a fault tree, to calculate system reliability characteristics, and to perform qualitative common cause failure analysis

Structural systems reliability analysis

International Nuclear Information System (INIS)

Frangopol, D.

1975-01-01

For an exact evaluation of the reliability of a structure it appears necessary to determine the distribution densities of the loads and resistances and to calculate the correlation coefficients between loads and between resistances. These statistical characteristics can be obtained only on the basis of a long activity period. In case that such studies are missing the statistical properties formulated here give upper and lower bounds of the reliability. (orig./HP) [de

Reliability analysis of containment isolation systems

International Nuclear Information System (INIS)

Pelto, P.J.; Ames, K.R.; Gallucci, R.H.

1985-06-01

This report summarizes the results of the Reliability Analysis of Containment Isolation System Project. Work was performed in five basic areas: design review, operating experience review, related research review, generic analysis and plant specific analysis. Licensee Event Reports (LERs) and Integrated Leak Rate Test (ILRT) reports provided the major sources of containment performance information used in this study. Data extracted from LERs were assembled into a computer data base. Qualitative and quantitative information developed for containment performance under normal operating conditions and design basis accidents indicate that there is room for improvement. A rough estimate of overall containment unavailability for relatively small leaks which violate plant technical specifications is 0.3. An estimate of containment unavailability due to large leakage events is in the range of 0.001 to 0.01. These estimates are dependent on several assumptions (particularly on event duration times) which are documented in the report

Sensitivity analysis in optimization and reliability problems

International Nuclear Information System (INIS)

Castillo, Enrique; Minguez, Roberto; Castillo, Carmen

2008-01-01

The paper starts giving the main results that allow a sensitivity analysis to be performed in a general optimization problem, including sensitivities of the objective function, the primal and the dual variables with respect to data. In particular, general results are given for non-linear programming, and closed formulas for linear programming problems are supplied. Next, the methods are applied to a collection of civil engineering reliability problems, which includes a bridge crane, a retaining wall and a composite breakwater. Finally, the sensitivity analysis formulas are extended to calculus of variations problems and a slope stability problem is used to illustrate the methods

Sensitivity analysis in optimization and reliability problems

Energy Technology Data Exchange (ETDEWEB)

Castillo, Enrique [Department of Applied Mathematics and Computational Sciences, University of Cantabria, Avda. Castros s/n., 39005 Santander (Spain)], E-mail: castie@unican.es; Minguez, Roberto [Department of Applied Mathematics, University of Castilla-La Mancha, 13071 Ciudad Real (Spain)], E-mail: roberto.minguez@uclm.es; Castillo, Carmen [Department of Civil Engineering, University of Castilla-La Mancha, 13071 Ciudad Real (Spain)], E-mail: mariacarmen.castillo@uclm.es

2008-12-15

The paper starts giving the main results that allow a sensitivity analysis to be performed in a general optimization problem, including sensitivities of the objective function, the primal and the dual variables with respect to data. In particular, general results are given for non-linear programming, and closed formulas for linear programming problems are supplied. Next, the methods are applied to a collection of civil engineering reliability problems, which includes a bridge crane, a retaining wall and a composite breakwater. Finally, the sensitivity analysis formulas are extended to calculus of variations problems and a slope stability problem is used to illustrate the methods.

Development and Reliability Analysis of HTR-PM Reactor Protection System

International Nuclear Information System (INIS)

Li Duo; Guo Chao; Xiong Huasheng

2014-01-01

High Temperature Gas-Cooled Reactor-Pebble bed Module (HTR-PM) digital Reactor Protection System (RPS) is a dedicated system, which is designed and developed according to HTR-PM NPP protection specifications. To decrease the probability of accident trips and increase the system reliability, HTR-PM RPS has such features as a framework of four redundant channels, two diverse sub-systems in each channel, and two level two-out-of-four logic voters. Reliability analysis of HTR-PM RPS is based on fault tree model. A fault tree is built based on HTR-PM RPS Failure Modes and Effects Analysis (FMEA), and special analysis is focused on the sub-tree of redundant channel ''2-out-of-4'' logic and the fault tree under one channel is bypassed. The qualitative analysis of fault tree, such as RPS weakness according to minimal cut sets, is summarized in the paper. (author)

Method of reliability allocation based on fault tree analysis and fuzzy math in nuclear power plants

International Nuclear Information System (INIS)

Chen Zhaobing; Deng Jian; Cao Xuewu

2005-01-01

Reliability allocation is a kind of a difficult multi-objective optimization problem. It can not only be applied to determine the reliability characteristic of reactor systems, subsystem and main components but also be performed to improve the design, operation and maintenance of nuclear plants. The fuzzy math known as one of the powerful tools for fuzzy optimization and the fault analysis deemed to be one of the effective methods of reliability analysis can be applied to the reliability allocation model so as to work out the problems of fuzzy characteristic of some factors and subsystem's choice respectively in this paper. Thus we develop a failure rate allocation model on the basis of the fault tree analysis and fuzzy math. For the choice of the reliability constraint factors, we choose the six important ones according to practical need for conducting the reliability allocation. The subsystem selected by the top-level fault tree analysis is to avoid allocating reliability for all the equipment and components including the unnecessary parts. During the reliability process, some factors can be calculated or measured quantitatively while others only can be assessed qualitatively by the expert rating method. So we adopt fuzzy decision and dualistic contrast to realize the reliability allocation with the help of fault tree analysis. Finally the example of the emergency diesel generator's reliability allocation is used to illustrate reliability allocation model and improve this model simple and applicable. (authors)

Optimal real time cost-benefit based demand response with intermittent resources

International Nuclear Information System (INIS)

Zareen, N.; Mustafa, M.W.; Sultana, U.; Nadia, R.; Khattak, M.A.

2015-01-01

Ever-increasing price of conventional energy resources and related environmental concern enforced to explore alternative energy sources. Inherent uncertainty of power generation and demand being strongly influenced by the electricity market has posed severe challenges for DRPs (Demand Response Programs). Definitely, the success of such uncertain energy systems under new market structures is critically decided by the advancement of innovative technical and financial tools. Recent exponential growth of DG (distributed generations) demanded both the grid reliability and financial cost–benefits analysis for deregulated electricity market stakeholders. Based on the SGT (signaling game theory), the paper presents a novel user-aware demand-management approach where the price are colligated with grid condition uncertainties to manage the peak residential loads. The degree of information disturbances are considered as a key factor for evaluating electricity bidding mechanisms in the presence of independent multi-generation resources and price-elastic demand. A correlation between the cost–benefit price and variable reliability of grid is established under uncertain generation and demand conditions. Impacts of the strategies on load shape, benefit of customers and the reduction of energy consumption are inspected and compared with Time-of-Used based DRPs. Simulation results show that the proposed DRP can significantly reduce or even eliminate peak-hour energy consumption, leading to a substantial raise of revenues with 18% increase in the load reduction and a considerable improvement in system reliability is evidenced. - Highlights: • Proposed an optimal real time cost-benefit based demand response model. • Used signaling game theory for the information disturbances in deregulated market. • Introduced a correlation between the cost–benefit price and variable grid reliability. • Derive robust bidding strategies for utility/customers successful participation. �

LIF: A new Kriging based learning function and its application to structural reliability analysis

International Nuclear Information System (INIS)

Sun, Zhili; Wang, Jian; Li, Rui; Tong, Cao

2017-01-01

The main task of structural reliability analysis is to estimate failure probability of a studied structure taking randomness of input variables into account. To consider structural behavior practically, numerical models become more and more complicated and time-consuming, which increases the difficulty of reliability analysis. Therefore, sequential strategies of design of experiment (DoE) are raised. In this research, a new learning function, named least improvement function (LIF), is proposed to update DoE of Kriging based reliability analysis method. LIF values how much the accuracy of estimated failure probability will be improved if adding a given point into DoE. It takes both statistical information provided by the Kriging model and the joint probability density function of input variables into account, which is the most important difference from the existing learning functions. Maximum point of LIF is approximately determined with Markov Chain Monte Carlo(MCMC) simulation. A new reliability analysis method is developed based on the Kriging model, in which LIF, MCMC and Monte Carlo(MC) simulation are employed. Three examples are analyzed. Results show that LIF and the new method proposed in this research are very efficient when dealing with nonlinear performance function, small probability, complicated limit state and engineering problems with high dimension. - Highlights: • Least improvement function (LIF) is proposed for structural reliability analysis. • LIF takes both Kriging based statistical information and joint PDF into account. • A reliability analysis method is constructed based on Kriging, MCS and LIF.

Using reliability analysis to support decision making\\ud in phased mission systems

OpenAIRE

Zhang, Yang; Prescott, Darren

2017-01-01

Due to the environments in which they will operate, future autonomous systems must be capable of reconfiguring quickly and safely following faults or environmental changes. Past research has shown how, by considering autonomous systems to perform phased missions, reliability analysis can support decision making by allowing comparison of the probability of success of different missions following reconfiguration. Binary Decision Diagrams (BDDs) offer fast, accurate reliability analysis that cou...

Human Reliability Analysis in Support of Risk Assessment for Positive Train Control

Science.gov (United States)

2003-06-01

This report describes an approach to evaluating the reliability of human actions that are modeled in a probabilistic risk assessment : (PRA) of train control operations. This approach to human reliability analysis (HRA) has been applied in the case o...

An Intelligent Method for Structural Reliability Analysis Based on Response Surface

Institute of Scientific and Technical Information of China (English)

桂劲松; 刘红; 康海贵

2004-01-01

As water depth increases, the structural safety and reliability of a system become more and more important and challenging. Therefore, the structural reliability method must be applied in ocean engineering design such as offshore platform design. If the performance function is known in structural reliability analysis, the first-order second-moment method is often used. If the performance function could not be definitely expressed, the response surface method is always used because it has a very clear train of thought and simple programming. However, the traditional response surface method fits the response surface of quadratic polynomials where the problem of accuracy could not be solved, because the true limit state surface can be fitted well only in the area near the checking point. In this paper, an intelligent computing method based on the whole response surface is proposed, which can be used for the situation where the performance function could not be definitely expressed in structural reliability analysis. In this method, a response surface of the fuzzy neural network for the whole area should be constructed first, and then the structural reliability can be calculated by the genetic algorithm. In the proposed method, all the sample points for the training network come from the whole area, so the true limit state surface in the whole area can be fitted. Through calculational examples and comparative analysis, it can be known that the proposed method is much better than the traditional response surface method of quadratic polynomials, because, the amount of calculation of finite element analysis is largely reduced, the accuracy of calculation is improved,and the true limit state surface can be fitted very well in the whole area. So, the method proposed in this paper is suitable for engineering application.

Who gains? allocation of freight transport user benefits from international infrastructure projects in multicountry cost-benefit analysis

DEFF Research Database (Denmark)

Fosgerau, Mogens; Kristensen, Niels Buus

2005-01-01

A public decision by several countries on whether to cofinance an international infrastructure project is the subject of a cost-benefit analysis (CBA). The CBA elements are broken out and analyzed for each country. The issue of freight user benefits is discussed, and results are derived from...

Dynamic decision-making for reliability and maintenance analysis of manufacturing systems based on failure effects

Science.gov (United States)

Zhang, Ding; Zhang, Yingjie

2017-09-01

A framework for reliability and maintenance analysis of job shop manufacturing systems is proposed in this paper. An efficient preventive maintenance (PM) policy in terms of failure effects analysis (FEA) is proposed. Subsequently, reliability evaluation and component importance measure based on FEA are performed under the PM policy. A job shop manufacturing system is applied to validate the reliability evaluation and dynamic maintenance policy. Obtained results are compared with existed methods and the effectiveness is validated. Some vague understandings for issues such as network modelling, vulnerabilities identification, the evaluation criteria of repairable systems, as well as PM policy during manufacturing system reliability analysis are elaborated. This framework can help for reliability optimisation and rational maintenance resources allocation of job shop manufacturing systems.

[A cost-benefit analysis of occupational disease reporting in China].

Science.gov (United States)

Tang, X Z; Zeng, Q; Liu, D S

2017-03-20

Objective: To perform a cost-benefit analysis of the occupational disease reporting system in China, and to provide a basis for effective resource allocation. Methods: The data on the cost of occupational diseases were collected from China Health Statistics Yearbook 2013, the estimated benefit data were collected from published articles in China and foreign countries, and the probability data were collected from the occupational diseasereports published by health and family planning administrative departments. Adecision-making tree was used for the cost-benefit analysis. Results: The estimated cost of occupational disease reporting was about 102.47 million yuan/year, consisting of a cost of reporting in national medical institutions of 1.25 million yuan/year, a management cost of 30.35 million yuan/year, a management cost in local public health institutions of 69.80 million yuan/year, a management cost in national public health institutions of 370 thousand yuan/year, and a cost of construction and maintenance of reporting system of 700 thousand yuan/year. The results of the decision tree analysis showed that when an occupational disease monitoring system was established, the incremental input for occupational disease monitoring and prevention/control was 2.1 billion yuan/year, the output was 6.5 billion yuan/year, and the benefit of occupational disease reporting system was 4.4 billion yuan/year. Conclusion: The benefit of occupational disease reporting system depends on the cost-benefit of occupational disease prevention and control measures, and proper prevention and control measures are extremely important for improving the benefit of occupational disease reporting system.

Reliability analysis of production ships with emphasis on load combination and ultimate strength

Energy Technology Data Exchange (ETDEWEB)

Wang, Xiaozhi

1995-05-01

This thesis deals with ultimate strength and reliability analysis of offshore production ships, accounting for stochastic load combinations, using a typical North Sea production ship for reference. A review of methods for structural reliability analysis is presented. Probabilistic methods are established for the still water and vertical wave bending moments. Linear stress analysis of a midships transverse frame is carried out, four different finite element models are assessed. Upon verification of the general finite element code ABAQUS with a typical ship transverse girder example, for which test results are available, ultimate strength analysis of the reference transverse frame is made to obtain the ultimate load factors associated with the specified pressure loads in Det norske Veritas Classification rules for ships and rules for production vessels. Reliability analysis is performed to develop appropriate design criteria for the transverse structure. It is found that the transverse frame failure mode does not seem to contribute to the system collapse. Ultimate strength analysis of the longitudinally stiffened panels is performed, accounting for the combined biaxial and lateral loading. Reliability based design of the longitudinally stiffened bottom and deck panels is accomplished regarding the collapse mode under combined biaxial and lateral loads. 107 refs., 76 refs., 37 tabs.

Risk-benefit analysis of 18FDG PET cancer screening

International Nuclear Information System (INIS)

Murano, Takeshi; Daisaki, Hiromitsu; Terauchi, Takashi; Iinuma, Takeshi; Tateno, Yukio; Tateishi, Ukihide; Kato, Kazuaki; Inoue, Tomio

2008-01-01

The benefits of 18 F-fluorodeoxyglucose ( 18 FDG) positron emission tomography (PET) cancer screening are expected to include a large population of examinees and are intended for a healthy group. Therefore, we attempted to determine the benefit/risk ratio, estimated risk of radiation exposure, and benefit of cancer detection. We used software that embodied the method of the International Commission on Radiological Protection (ICRP) to calculate the average duration of life of radiation exposure. We calculated the lifesaving person years of benefit to be obtained by 18 FDG PET cancer screening detection. We also calculated the benefit/risk ratio using life-shortening and lifesaving person years. According to age, the benefit/risk ratio was more than 1 at 35-39 years old for males and 30-34 years old for females. 18 FDG PET cancer screening also is effective for examinees older than this. A risk-benefit analysis of 18 FDG-PET/computed tomography (CT) cancer screening will be necessary in the future. (author)

Systems reliability/structural reliability

International Nuclear Information System (INIS)

Green, A.E.

1980-01-01

The question of reliability technology using quantified techniques is considered for systems and structures. Systems reliability analysis has progressed to a viable and proven methodology whereas this has yet to be fully achieved for large scale structures. Structural loading variants over the half-time of the plant are considered to be more difficult to analyse than for systems, even though a relatively crude model may be a necessary starting point. Various reliability characteristics and environmental conditions are considered which enter this problem. The rare event situation is briefly mentioned together with aspects of proof testing and normal and upset loading conditions. (orig.)

Application of Reliability Analysis for Optimal Design of Monolithic Vertical Wall Breakwaters

DEFF Research Database (Denmark)

Burcharth, H. F.; Sørensen, John Dalsgaard; Christiani, E.

1995-01-01

Reliability analysis and reliability-based design of monolithic vertical wall breakwaters are considered. Probabilistic models of some of the most important failure modes are described. The failures are sliding and slip surface failure of a rubble mound and a clay foundation. Relevant design...

Reliability Analysis of the CERN Radiation Monitoring Electronic System CROME

CERN Document Server

AUTHOR|(CDS)2126870

For the new in-house developed CERN Radiation Monitoring Electronic System (CROME) a reliability analysis is necessary to ensure compliance with the statu-tory requirements regarding the Safety Integrity Level. The required Safety Integrity Level by IEC 60532 standard is SIL 2 (for the Safety Integrated Functions Measurement, Alarm Triggering and Interlock Triggering). The first step of the reliability analysis was a system and functional analysis which served as basis for the implementation of the CROME system in the software “Iso-graph”. In the “Prediction” module of Isograph the failure rates of all components were calculated. Failure rates for passive components were calculated by the Military Standard 217 and failure rates for active components were obtained from lifetime tests by the manufacturers. The FMEA was carried out together with the board designers and implemented in the “FMECA” module of Isograph. The FMEA served as basis for the Fault Tree Analysis and the detection of weak points...

Condition-based fault tree analysis (CBFTA): A new method for improved fault tree analysis (FTA), reliability and safety calculations

International Nuclear Information System (INIS)

Shalev, Dan M.; Tiran, Joseph

2007-01-01

Condition-based maintenance methods have changed systems reliability in general and individual systems in particular. Yet, this change does not affect system reliability analysis. System fault tree analysis (FTA) is performed during the design phase. It uses components failure rates derived from available sources as handbooks, etc. Condition-based fault tree analysis (CBFTA) starts with the known FTA. Condition monitoring (CM) methods applied to systems (e.g. vibration analysis, oil analysis, electric current analysis, bearing CM, electric motor CM, and so forth) are used to determine updated failure rate values of sensitive components. The CBFTA method accepts updated failure rates and applies them to the FTA. The CBFTA recalculates periodically the top event (TE) failure rate (λ TE ) thus determining the probability of system failure and the probability of successful system operation-i.e. the system's reliability. FTA is a tool for enhancing system reliability during the design stages. But, it has disadvantages, mainly it does not relate to a specific system undergoing maintenance. CBFTA is tool for updating reliability values of a specific system and for calculating the residual life according to the system's monitored conditions. Using CBFTA, the original FTA is ameliorated to a practical tool for use during the system's field life phase, not just during system design phase. This paper describes the CBFTA method and its advantages are demonstrated by an example

Cost Benefit Analysis: Bypass of Prešov city

Directory of Open Access Journals (Sweden)

Margorínová Martina

2017-01-01

Full Text Available The paper describes decision making process based on economic evaluation, i.e. Cost Benefit Analysis for motorway bypass of the Prešov city. Three variants were evaluated by means of the Highway Development and Management Tool (HDM-4. HDM-4 is a software system for evaluating options for investing in road transport infrastructure. Vehicle operating costs and travel time costs were monetized with the use of the software. The investment opportunities were evaluated in terms of Cost Benefit Analysis results, i.e. economic indicators.

Problems Related to Use of Some Terms in System Reliability Analysis

Directory of Open Access Journals (Sweden)

Nadezda Hanusova

2004-01-01

Full Text Available The paper deals with problems of using dependability terms, defined in actual standard STN IEC 50 (191: International electrotechnical dictionary, chap. 191: Dependability and quality of service (1993, in a technical systems dependability analysis. The goal of the paper is to find a relation between terms introduced in the mentioned standard and used in the technical systems dependability analysis and rules and practices used in a system analysis of the system theory. Description of a part of the system life cycle related to reliability is used as a starting point. The part of a system life cycle is described by the state diagram and reliability relevant therms are assigned.

Measuring reliability under epistemic uncertainty: Review on non-probabilistic reliability metrics

Directory of Open Access Journals (Sweden)

Kang Rui

2016-06-01

Full Text Available In this paper, a systematic review of non-probabilistic reliability metrics is conducted to assist the selection of appropriate reliability metrics to model the influence of epistemic uncertainty. Five frequently used non-probabilistic reliability metrics are critically reviewed, i.e., evidence-theory-based reliability metrics, interval-analysis-based reliability metrics, fuzzy-interval-analysis-based reliability metrics, possibility-theory-based reliability metrics (posbist reliability and uncertainty-theory-based reliability metrics (belief reliability. It is pointed out that a qualified reliability metric that is able to consider the effect of epistemic uncertainty needs to (1 compensate the conservatism in the estimations of the component-level reliability metrics caused by epistemic uncertainty, and (2 satisfy the duality axiom, otherwise it might lead to paradoxical and confusing results in engineering applications. The five commonly used non-probabilistic reliability metrics are compared in terms of these two properties, and the comparison can serve as a basis for the selection of the appropriate reliability metrics.

Reliability calculations

International Nuclear Information System (INIS)

Petersen, K.E.

1986-03-01

Risk and reliability analysis is increasingly being used in evaluations of plant safety and plant reliability. The analysis can be performed either during the design process or during the operation time, with the purpose to improve the safety or the reliability. Due to plant complexity and safety and availability requirements, sophisticated tools, which are flexible and efficient, are needed. Such tools have been developed in the last 20 years and they have to be continuously refined to meet the growing requirements. Two different areas of application were analysed. In structural reliability probabilistic approaches have been introduced in some cases for the calculation of the reliability of structures or components. A new computer program has been developed based upon numerical integration in several variables. In systems reliability Monte Carlo simulation programs are used especially in analysis of very complex systems. In order to increase the applicability of the programs variance reduction techniques can be applied to speed up the calculation process. Variance reduction techniques have been studied and procedures for implementation of importance sampling are suggested. (author)

Subset simulation for structural reliability sensitivity analysis

International Nuclear Information System (INIS)

Song Shufang; Lu Zhenzhou; Qiao Hongwei

2009-01-01

Based on two procedures for efficiently generating conditional samples, i.e. Markov chain Monte Carlo (MCMC) simulation and importance sampling (IS), two reliability sensitivity (RS) algorithms are presented. On the basis of reliability analysis of Subset simulation (Subsim), the RS of the failure probability with respect to the distribution parameter of the basic variable is transformed as a set of RS of conditional failure probabilities with respect to the distribution parameter of the basic variable. By use of the conditional samples generated by MCMC simulation and IS, procedures are established to estimate the RS of the conditional failure probabilities. The formulae of the RS estimator, its variance and its coefficient of variation are derived in detail. The results of the illustrations show high efficiency and high precision of the presented algorithms, and it is suitable for highly nonlinear limit state equation and structural system with single and multiple failure modes

Cost-benefit analysis on FBR cycle R and D for the world

International Nuclear Information System (INIS)

Kawasaki, Hirotsugu

2006-01-01

This analysis was estimated on the assumption that the nuclear power generation will be changed by FBR and both LWR and FBR indicate same nuclear power generation cost and the environmental load. The cost-benefit analysis results on FBR cycle R and D in the world showed that increase of power generation cost with increase of uranium fuel cost will be avoided and decrease of power generation cost by introducing FBR. The cost-benefit analysis results on FBR cycle R and D in Japan showed that about 9 billions yen will be obtained by the above two economic effects. Cost-benefit effects by introducing FBR, economic estimation method of cost-benefit effect, range and contents of cost-benefit effect on FBR R and D, preconditions of evaluation, and evaluation results are explained. (S.Y.)

Integral Cost-Benefit Analysis of Maglev Rail Projects Under Market Imperfections

Directory of Open Access Journals (Sweden)

J. Paul Elhorst

2008-07-01

Full Text Available This article evaluates a new mode of high speed ground transportation, the magnetic levitation rail system (Maglev. The outcomes of this evaluation provide policy information on the interregional redistribution of employment and population and the national welfare improvement of two Dutch urban-conglomeration and two Dutch core-periphery projects. This article also compares the results of an integral cost- benefit analysis with those of a conventional cost-benefit analysis and concludes that the additional economic benefits due to market imperfections vary from –1% to +38% of the direct transport benefits, depending on the type of regions connected and the general condition of the economy.

Needs-based sewerage prioritization: alternative to conventional cost-benefit analysis.

Science.gov (United States)

Rashid, Md M; Hayes, Donald F

2011-10-01

This paper presents an empirical approach to select and prioritize sewerage projects within set budgetary limitations. The methodology includes a model which quantifies benefits of a sewerage project as an index or dimensionless number. The index considers need and urgency of sewerage and other project goals. Benefit is defined as the difference in anticipated impact between the current condition (without the project) and the expected condition with the project. Anticipated benefits primarily include reduction in environmental pollution, reduction of human diseases and morbidity, and other tangible and intangible improvement. This approach is a powerful decision tool for sewerage prioritization and an effective alternative to conventional cost-benefit analysis. Unlike conventional analysis, this approach makes no attempt to convert project benefits and other impacts into a monetary measure. This work recognizes that the decision to provide sewerage based solely on net benefits is not practical. Instead, benefit-cost ratios (B/C) are calculated utilizing cost-effectiveness approach. Using these ratios, 16 unserviced areas of Ensenada, Mexico are ranked. The prioritization rankings produced by this method must be further scrutinized and carefully reviewed for logic, accuracy of input data, and practicality of implementation. A similar framework may also be useful for prioritizing other public works projects. Copyright © 2011 Elsevier Ltd. All rights reserved.

Fifty Years of THERP and Human Reliability Analysis

Energy Technology Data Exchange (ETDEWEB)

Ronald L. Boring

2012-06-01

In 1962 at a Human Factors Society symposium, Alan Swain presented a paper introducing a Technique for Human Error Rate Prediction (THERP). This was followed in 1963 by a Sandia Laboratories monograph outlining basic human error quantification using THERP and, in 1964, by a special journal edition of Human Factors on quantification of human performance. Throughout the 1960s, Swain and his colleagues focused on collecting human performance data for the Sandia Human Error Rate Bank (SHERB), primarily in connection with supporting the reliability of nuclear weapons assembly in the US. In 1969, Swain met with Jens Rasmussen of Risø National Laboratory and discussed the applicability of THERP to nuclear power applications. By 1975, in WASH-1400, Swain had articulated the use of THERP for nuclear power applications, and the approach was finalized in the watershed publication of the NUREG/CR-1278 in 1983. THERP is now 50 years old, and remains the most well known and most widely used HRA method. In this paper, the author discusses the history of THERP, based on published reports and personal communication and interviews with Swain. The author also outlines the significance of THERP. The foundations of human reliability analysis are found in THERP: human failure events, task analysis, performance shaping factors, human error probabilities, dependence, event trees, recovery, and pre- and post-initiating events were all introduced in THERP. While THERP is not without its detractors, and it is showing signs of its age in the face of newer technological applications, the longevity of THERP is a testament of its tremendous significance. THERP started the field of human reliability analysis. This paper concludes with a discussion of THERP in the context of newer methods, which can be seen as extensions of or departures from Swain’s pioneering work.

Reliability of Computerized Neurocognitive Tests for Concussion Assessment: A Meta-Analysis.

Science.gov (United States)

Farnsworth, James L; Dargo, Lucas; Ragan, Brian G; Kang, Minsoo

2017-09-01

  Although widely used, computerized neurocognitive tests (CNTs) have been criticized because of low reliability and poor sensitivity. A systematic review was published summarizing the reliability of Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) scores; however, this was limited to a single CNT. Expansion of the previous review to include additional CNTs and a meta-analysis is needed. Therefore, our purpose was to analyze reliability data for CNTs using meta-analysis and examine moderating factors that may influence reliability.   A systematic literature search (key terms: reliability, computerized neurocognitive test, concussion) of electronic databases (MEDLINE, PubMed, Google Scholar, and SPORTDiscus) was conducted to identify relevant studies.   Studies were included if they met all of the following criteria: used a test-retest design, involved at least 1 CNT, provided sufficient statistical data to allow for effect-size calculation, and were published in English.   Two independent reviewers investigated each article to assess inclusion criteria. Eighteen studies involving 2674 participants were retained. Intraclass correlation coefficients were extracted to calculate effect sizes and determine overall reliability. The Fisher Z transformation adjusted for sampling error associated with averaging correlations. Moderator analyses were conducted to evaluate the effects of the length of the test-retest interval, intraclass correlation coefficient model selection, participant demographics, and study design on reliability. Heterogeneity was evaluated using the Cochran Q statistic.   The proportion of acceptable outcomes was greatest for the Axon Sports CogState Test (75%) and lowest for the ImPACT (25%). Moderator analyses indicated that the type of intraclass correlation coefficient model used significantly influenced effect-size estimates, accounting for 17% of the variation in reliability.   The Axon Sports CogState Test, which

Probabilistic economic analysis of green roof benefits for policy design

International Nuclear Information System (INIS)

Clark, C.; Adriaens, P.; Talbot, B.

2006-01-01

The installation costs of green roofs continue to deter widespread use of green roof technology. Analyses of the boundary conditions for the cost differential between a green roof and a conventional roof are usually compared to environmental benefits such as storm water reduction and building energy savings. However, evidence is emerging that green roofs may play a role in urban air quality improvement. This paper discussed a methodology for developing probabilistic ranges of benefits and cost analyses. A probabilistic analysis was conducted to prepare a generalized cost-benefit analysis for application to a range of green roof projects. Environmental benefits of roof greening were quantified on a per unit surface area to assess environmental impact at the building scale. Parameters included conventional and green roof installation costs; storm water fees and fee reductions for green roofs; energy costs due to heat flux and the resultant savings through the installation of a green roof and the additional economic valuation of the public health benefits due to air pollution mitigation. Results were then integrated into an economic model to determine the length of time required for a return on investment in a green roof, assuming that a traditional roof would require replacement after 20 years. A net present value analysis was performed for an average-sized university roof. Results of the study showed that a valuation of environmental benefits can reduce the time required for a return on investment in a moderately priced green roof. While reduced installation costs reduced the time required for a return on investment, optimizing the green roof system for maximum environmental benefit had a greater potential to provide a higher return. It was concluded that the benefit of improved air quality should not be ignored by green roof policy-makers as a valuation tool. 10 refs., 3 tabs., 1 fig

Inclusion of fatigue effects in human reliability analysis

International Nuclear Information System (INIS)

Griffith, Candice D.; Mahadevan, Sankaran

2011-01-01

The effect of fatigue on human performance has been observed to be an important factor in many industrial accidents. However, defining and measuring fatigue is not easily accomplished. This creates difficulties in including fatigue effects in probabilistic risk assessments (PRA) of complex engineering systems that seek to include human reliability analysis (HRA). Thus the objectives of this paper are to discuss (1) the importance of the effects of fatigue on performance, (2) the difficulties associated with defining and measuring fatigue, (3) the current status of inclusion of fatigue in HRA methods, and (4) the future directions and challenges for the inclusion of fatigue, specifically sleep deprivation, in HRA. - Highlights: →We highlight the need for fatigue and sleep deprivation effects on performance to be included in human reliability analysis (HRA) methods. Current methods do not explicitly include sleep deprivation effects. → We discuss the difficulties in defining and measuring fatigue. → We review sleep deprivation research, and discuss the limitations and future needs of the current HRA methods.

Reliability analysis of the reactor protection system with fault diagnosis

International Nuclear Information System (INIS)

Lee, D.Y.; Han, J.B.; Lyou, J.

2004-01-01

The main function of a reactor protection system (RPS) is to maintain the reactor core integrity and reactor coolant system pressure boundary. The RPS consists of the 2-out-of-m redundant architecture to assure a reliable operation. The system reliability of the RPS is a very important factor for the probability safety assessment (PSA) evaluation in the nuclear field. To evaluate the system failure rate of the k-out-of-m redundant system is not so easy with the deterministic method. In this paper, the reliability analysis method using the binomial process is suggested to calculate the failure rate of the RPS system with a fault diagnosis function. The suggested method is compared with the result of the Markov process to verify the validation of the suggested method, and applied to the several kinds of RPS architectures for a comparative evaluation of the reliability. (orig.)

Reliability Analysis for Adhesive Bonded Composite Stepped Lap Joints Loaded in Fatigue

DEFF Research Database (Denmark)

Kimiaeifar, Amin; Sørensen, John Dalsgaard; Lund, Erik

2012-01-01

-1, where partial safety factors are introduced together with characteristic values. Asymptotic sampling is used to estimate the reliability with support points generated by randomized Sobol sequences. The predicted reliability level is compared with the implicitly required target reliability level defined......This paper describes a probabilistic approach to calculate the reliability of adhesive bonded composite stepped lap joints loaded in fatigue using three- dimensional finite element analysis (FEA). A method for progressive damage modelling is used to assess fatigue damage accumulation and residual...... by the wind turbine standard IEC 61400-1. Finally, an approach for the assessment of the reliability of adhesive bonded composite stepped lap joints loaded in fatigue is presented. The introduced methodology can be applied in the same way to calculate the reliability level of wind turbine blade components...

An Evidential Reasoning-Based CREAM to Human Reliability Analysis in Maritime Accident Process.

Science.gov (United States)

Wu, Bing; Yan, Xinping; Wang, Yang; Soares, C Guedes

2017-10-01

This article proposes a modified cognitive reliability and error analysis method (CREAM) for estimating the human error probability in the maritime accident process on the basis of an evidential reasoning approach. This modified CREAM is developed to precisely quantify the linguistic variables of the common performance conditions and to overcome the problem of ignoring the uncertainty caused by incomplete information in the existing CREAM models. Moreover, this article views maritime accident development from the sequential perspective, where a scenario- and barrier-based framework is proposed to describe the maritime accident process. This evidential reasoning-based CREAM approach together with the proposed accident development framework are applied to human reliability analysis of a ship capsizing accident. It will facilitate subjective human reliability analysis in different engineering systems where uncertainty exists in practice. © 2017 Society for Risk Analysis.

Reliability Approach of a Compressor System using Reliability Block ...

African Journals Online (AJOL)

pc

2018-03-05

Mar 5, 2018 ... This paper presents a reliability analysis of such a system using reliability ... Keywords-compressor system, reliability, reliability block diagram, RBD .... the same structure has been kept with the three subsystems: air flow, oil flow and .... and Safety in Engineering Design", Springer, 2009. [3] P. O'Connor ...

Infrastructures and Life-Cycle Cost-Benefit Analysis

DEFF Research Database (Denmark)

Thoft-Christensen, Palle

2012-01-01

Design and maintenance of infrastructures using Life-Cycle Cost-Benefit analysis is discussed in this paper with special emphasis on users costs. This is for several infrastructures such as bridges, highways etc. of great importance. Repair or/and failure of infrastructures will usually result...

Statistical reliability analyses of two wood plastic composite extrusion processes

International Nuclear Information System (INIS)

Crookston, Kevin A.; Mark Young, Timothy; Harper, David; Guess, Frank M.

2011-01-01

Estimates of the reliability of wood plastic composites (WPC) are explored for two industrial extrusion lines. The goal of the paper is to use parametric and non-parametric analyses to examine potential differences in the WPC metrics of reliability for the two extrusion lines that may be helpful for use by the practitioner. A parametric analysis of the extrusion lines reveals some similarities and disparities in the best models; however, a non-parametric analysis reveals unique and insightful differences between Kaplan-Meier survival curves for the modulus of elasticity (MOE) and modulus of rupture (MOR) of the WPC industrial data. The distinctive non-parametric comparisons indicate the source of the differences in strength between the 10.2% and 48.0% fractiles [3,183-3,517 MPa] for MOE and for MOR between the 2.0% and 95.1% fractiles [18.9-25.7 MPa]. Distribution fitting as related to selection of the proper statistical methods is discussed with relevance to estimating the reliability of WPC. The ability to detect statistical differences in the product reliability of WPC between extrusion processes may benefit WPC producers in improving product reliability and safety of this widely used house-decking product. The approach can be applied to many other safety and complex system lifetime comparisons.

Cost-benefit analysis of the ATM automatic deposit service

Directory of Open Access Journals (Sweden)

Ivica Županović

2015-03-01

Full Text Available Bankers and other financial experts have analyzed the value of automated teller machines (ATM in terms of growing consumer demand, rising costs of technology development, decreasing profitability and market share. This paper presents a step-by-step cost-benefit analysis of the ATM automatic deposit service. The first step is to determine user attitudes towards using ATM automatic deposit service by using the Technology Acceptance Model (TAM. The second step is to determine location priorities for ATMs that provide automatic deposit services using the Analytic Hierarchy Process (AHP model. The results of the previous steps enable a highly efficient application of cost-benefit analysis for evaluating costs and benefits of automatic deposit services. To understand fully the proposed procedure outside of theoretical terms, a real-world application of a case study is conducted.

Reliability-based optimization of engineering structures

DEFF Research Database (Denmark)

Sørensen, John Dalsgaard

2008-01-01

The theoretical basis for reliability-based structural optimization within the framework of Bayesian statistical decision theory is briefly described. Reliability-based cost benefit problems are formulated and exemplitied with structural optimization. The basic reliability-based optimization...... problems are generalized to the following extensions: interactive optimization, inspection and repair costs, systematic reconstruction, re-assessment of existing structures. Illustrative examples are presented including a simple introductory example, a decision problem related to bridge re...

Quality of the Critical Incident Technique in practice: Interrater reliability and users' acceptance under real conditions

Directory of Open Access Journals (Sweden)

ANNA KOCH

2009-03-01

Full Text Available The Critical Incident Technique (CIT is a widely used task analysis method in personnel psychology. While studies on psychometric properties of the CIT so far primarily took into account relevance ratings of task-lists or attributes, and hence, only a smaller or adapted part of the CIT, little is known about the psychometric properties of the complete CIT in its most meaningful and fruitful way. Therefore, the aim of the present study was to assess interrater reliability and the participants’ view of the CIT under real conditions and especially to provide data for the key step of the CIT: the classification of behavior descriptions into requirements. Additionally, the cost-benefit-ratio and practicability were rated from the participants’ views as an important indicator for the acceptance of the task analysis approach in practice. Instructors of German Institutions for Statutory Accidents Insurance and Prevention as well as their supervisors took part in a job analysis with the CIT. Moderate interrater reliability for the relevance rating was found while the classification step yielded unexpectedly low coefficients for interrater reliability. The cost-benefit-ratio and practicability of the complete CIT were rated very positive. The results are discussed in relation to determinants that facilitate or impede the application of task analysis procedures.

Qualitative analysis in reliability and safety studies

International Nuclear Information System (INIS)

Worrell, R.B.; Burdick, G.R.

1976-01-01

The qualitative evaluation of system logic models is described as it pertains to assessing the reliability and safety characteristics of nuclear systems. Qualitative analysis of system logic models, i.e., models couched in an event (Boolean) algebra, is defined, and the advantages inherent in qualitative analysis are explained. Certain qualitative procedures that were developed as a part of fault-tree analysis are presented for illustration. Five fault-tree analysis computer-programs that contain a qualitative procedure for determining minimal cut sets are surveyed. For each program the minimal cut-set algorithm and limitations on its use are described. The recently developed common-cause analysis for studying the effect of common-causes of failure on system behavior is explained. This qualitative procedure does not require altering the fault tree, but does use minimal cut sets from the fault tree as part of its input. The method is applied using two different computer programs. 25 refs

A discrete-time Bayesian network reliability modeling and analysis framework

International Nuclear Information System (INIS)

Boudali, H.; Dugan, J.B.

2005-01-01

Dependability tools are becoming an indispensable tool for modeling and analyzing (critical) systems. However the growing complexity of such systems calls for increasing sophistication of these tools. Dependability tools need to not only capture the complex dynamic behavior of the system components, but they must be also easy to use, intuitive, and computationally efficient. In general, current tools have a number of shortcomings including lack of modeling power, incapacity to efficiently handle general component failure distributions, and ineffectiveness in solving large models that exhibit complex dependencies between their components. We propose a novel reliability modeling and analysis framework based on the Bayesian network (BN) formalism. The overall approach is to investigate timed Bayesian networks and to find a suitable reliability framework for dynamic systems. We have applied our methodology to two example systems and preliminary results are promising. We have defined a discrete-time BN reliability formalism and demonstrated its capabilities from a modeling and analysis point of view. This research shows that a BN based reliability formalism is a powerful potential solution to modeling and analyzing various kinds of system components behaviors and interactions. Moreover, being based on the BN formalism, the framework is easy to use and intuitive for non-experts, and provides a basis for more advanced and useful analyses such as system diagnosis

On Bayesian System Reliability Analysis

Energy Technology Data Exchange (ETDEWEB)

Soerensen Ringi, M

1995-05-01

The view taken in this thesis is that reliability, the probability that a system will perform a required function for a stated period of time, depends on a person`s state of knowledge. Reliability changes as this state of knowledge changes, i.e. when new relevant information becomes available. Most existing models for system reliability prediction are developed in a classical framework of probability theory and they overlook some information that is always present. Probability is just an analytical tool to handle uncertainty, based on judgement and subjective opinions. It is argued that the Bayesian approach gives a much more comprehensive understanding of the foundations of probability than the so called frequentistic school. A new model for system reliability prediction is given in two papers. The model encloses the fact that component failures are dependent because of a shared operational environment. The suggested model also naturally permits learning from failure data of similar components in non identical environments. 85 refs.

On Bayesian System Reliability Analysis

International Nuclear Information System (INIS)

Soerensen Ringi, M.

1995-01-01

The view taken in this thesis is that reliability, the probability that a system will perform a required function for a stated period of time, depends on a person's state of knowledge. Reliability changes as this state of knowledge changes, i.e. when new relevant information becomes available. Most existing models for system reliability prediction are developed in a classical framework of probability theory and they overlook some information that is always present. Probability is just an analytical tool to handle uncertainty, based on judgement and subjective opinions. It is argued that the Bayesian approach gives a much more comprehensive understanding of the foundations of probability than the so called frequentistic school. A new model for system reliability prediction is given in two papers. The model encloses the fact that component failures are dependent because of a shared operational environment. The suggested model also naturally permits learning from failure data of similar components in non identical environments. 85 refs

Simulation Approach to Mission Risk and Reliability Analysis, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — It is proposed to develop and demonstrate an integrated total-system risk and reliability analysis approach that is based on dynamic, probabilistic simulation. This...

Dual discounting in cost-benefit analysis for environmental impacts

International Nuclear Information System (INIS)

Kula, Erhun; Evans, David

2011-01-01

Discounting has been a long-established intertemporal efficiency tool in cost-benefit analysis which focuses on project selection at communal level with a view to maximising the social welfare. However, with the relentless growth in environmental stress that, in good parts, stems from investment projects the established criterion in discounting appears to be inadequate especially when environmental issues are taken into consideration. This paper looks at how dual focus on efficiency and sustainability can be achieved by using dual discounting, i.e. discounting environmental benefits separately and differently from other costs and benefits and applies this alternative criterion to an afforestation scheme in the United Kingdom which contains carbon sequestration in addition to timber benefits.

Mechanical system reliability analysis using a combination of graph theory and Boolean function

International Nuclear Information System (INIS)

Tang, J.

2001-01-01

A new method based on graph theory and Boolean function for assessing reliability of mechanical systems is proposed. The procedure for this approach consists of two parts. By using the graph theory, the formula for the reliability of a mechanical system that considers the interrelations of subsystems or components is generated. Use of the Boolean function to examine the failure interactions of two particular elements of the system, followed with demonstrations of how to incorporate such failure dependencies into the analysis of larger systems, a constructive algorithm for quantifying the genuine interconnections between the subsystems or components is provided. The combination of graph theory and Boolean function provides an effective way to evaluate the reliability of a large, complex mechanical system. A numerical example demonstrates that this method an effective approaches in system reliability analysis

Stochastic reliability analysis using Fokker Planck equations

International Nuclear Information System (INIS)

Hari Prasad, M.; Rami Reddy, G.; Srividya, A.; Verma, A.K.

2011-01-01

The Fokker-Planck equation describes the time evolution of the probability density function of the velocity of a particle, and can be generalized to other observables as well. It is also known as the Kolmogorov forward equation (diffusion). Hence, for any process, which evolves with time, the probability density function as a function of time can be represented with Fokker-Planck equation. In stochastic reliability analysis one is more interested in finding out the reliability or failure probability of the components or structures as a function of time rather than instantaneous failure probabilities. In this analysis the variables are represented with random processes instead of random variables. A random processes can be either stationary or non stationary. If the random process is stationary then the failure probability doesn't change with time where as in the case of non stationary processes the failure probability changes with time. In the present paper Fokker Planck equations have been used to find out the probability density function of the non stationary random processes. In this paper a flow chart has been provided which describes step by step process for carrying out stochastic reliability analysis using Fokker-Planck equations. As a first step one has to identify the failure function as a function of random processes. Then one has to solve the Fokker-Planck equation for each random process. In this paper the Fokker-Planck equation has been solved by using Finite difference method. As a result one gets the probability density values of the random process in the sample space as well as time space. Later at each time step appropriate probability distribution has to be identified based on the available probability density values. For checking the better fitness of the data Kolmogorov-Smirnov Goodness of fit test has been performed. In this way one can find out the distribution of the random process at each time step. Once one has the probability distribution

Outline of cost-benefit analysis and a case study

Science.gov (United States)

Kellizy, A.

1978-01-01

The methodology of cost-benefit analysis is reviewed and a case study involving solar cell technology is presented. Emphasis is placed on simplifying the technique in order to permit a technical person not trained in economics to undertake a cost-benefit study comparing alternative approaches to a given problem. The role of economic analysis in management decision making is discussed. In simplifying the methodology it was necessary to restrict the scope and applicability of this report. Additional considerations and constraints are outlined. Examples are worked out to demonstrate the principles. A computer program which performs the computational aspects appears in the appendix.

High-Reliable PLC RTOS Development and RPS Structure Analysis

Energy Technology Data Exchange (ETDEWEB)

Sohn, H. S.; Song, D. Y.; Sohn, D. S.; Kim, J. H. [Enersys Co., Daejeon (Korea, Republic of)

2008-04-15

One of the KNICS objectives is to develop a platform for Nuclear Power Plant(NPP) I and C(Instrumentation and Control) system, especially plant protection system. The developed platform is POSAFE-Q and this work supports the development of POSAFE-Q with the development of high-reliable real-time operating system(RTOS) and programmable logic device(PLD) software. Another KNICS objective is to develop safety I and C systems, such as Reactor Protection System(RPS) and Engineered Safety Feature-Component Control System(ESF-CCS). This work plays an important role in the structure analysis for RPS. Validation and verification(V and V) of the safety critical software is an essential work to make digital plant protection system highly reliable and safe. Generally, the reliability and safety of software based system can be improved by strict quality assurance framework including the software development itself. In other words, through V and V, the reliability and safety of a system can be improved and the development activities like software requirement specification, software design specification, component tests, integration tests, and system tests shall be appropriately documented for V and V.

High-Reliable PLC RTOS Development and RPS Structure Analysis

International Nuclear Information System (INIS)

Sohn, H. S.; Song, D. Y.; Sohn, D. S.; Kim, J. H.

2008-04-01

One of the KNICS objectives is to develop a platform for Nuclear Power Plant(NPP) I and C(Instrumentation and Control) system, especially plant protection system. The developed platform is POSAFE-Q and this work supports the development of POSAFE-Q with the development of high-reliable real-time operating system(RTOS) and programmable logic device(PLD) software. Another KNICS objective is to develop safety I and C systems, such as Reactor Protection System(RPS) and Engineered Safety Feature-Component Control System(ESF-CCS). This work plays an important role in the structure analysis for RPS. Validation and verification(V and V) of the safety critical software is an essential work to make digital plant protection system highly reliable and safe. Generally, the reliability and safety of software based system can be improved by strict quality assurance framework including the software development itself. In other words, through V and V, the reliability and safety of a system can be improved and the development activities like software requirement specification, software design specification, component tests, integration tests, and system tests shall be appropriately documented for V and V.

PSA applications and piping reliability analysis: where do we stand?

International Nuclear Information System (INIS)

Lydell, B.O.Y.

1997-01-01

This reviews a recently proposed framework for piping reliability analysis. The framework was developed to promote critical interpretations of operational data on pipe failures, and to support application-specific-parameter estimation

Enabling More than Moore: Accelerated Reliability Testing and Risk Analysis for Advanced Electronics Packaging

Science.gov (United States)

Ghaffarian, Reza; Evans, John W.

2014-01-01

For five decades, the semiconductor industry has distinguished itself by the rapid pace of improvement in miniaturization of electronics products-Moore's Law. Now, scaling hits a brick wall, a paradigm shift. The industry roadmaps recognized the scaling limitation and project that packaging technologies will meet further miniaturization needs or ak.a "More than Moore". This paper presents packaging technology trends and accelerated reliability testing methods currently being practiced. Then, it presents industry status on key advanced electronic packages, factors affecting accelerated solder joint reliability of area array packages, and IPC/JEDEC/Mil specifications for characterizations of assemblies under accelerated thermal and mechanical loading. Finally, it presents an examples demonstrating how Accelerated Testing and Analysis have been effectively employed in the development of complex spacecraft thereby reducing risk. Quantitative assessments necessarily involve the mathematics of probability and statistics. In addition, accelerated tests need to be designed which consider the desired risk posture and schedule for particular project. Such assessments relieve risks without imposing additional costs. and constraints that are not value added for a particular mission. Furthermore, in the course of development of complex systems, variances and defects will inevitably present themselves and require a decision concerning their disposition, necessitating quantitative assessments. In summary, this paper presents a comprehensive view point, from technology to systems, including the benefits and impact of accelerated testing in offsetting risk.

Evolving Cuban-CARICOM relations : a comparative cost/benefit analysis

Directory of Open Access Journals (Sweden)

Michael Erisman

1995-01-01

Full Text Available Survey of the basic developmental dynamics involved in the evolving Cuban-CARICOM relationship. On the basis of a cost-risk/benefit analysis, the author provides some projections regarding the future of this relationship. He concludes that there appear sufficient potential benefits for both sides to deepen the relationship. Cuban-CARICOM integration, however, has no top priority for either partner.

Reliability analysis and prediction of mixed mode load using Markov Chain Model

International Nuclear Information System (INIS)

Nikabdullah, N.; Singh, S. S. K.; Alebrahim, R.; Azizi, M. A.; K, Elwaleed A.; Noorani, M. S. M.

2014-01-01

The aim of this paper is to present the reliability analysis and prediction of mixed mode loading by using a simple two state Markov Chain Model for an automotive crankshaft. The reliability analysis and prediction for any automotive component or structure is important for analyzing and measuring the failure to increase the design life, eliminate or reduce the likelihood of failures and safety risk. The mechanical failures of the crankshaft are due of high bending and torsion stress concentration from high cycle and low rotating bending and torsional stress. The Markov Chain was used to model the two states based on the probability of failure due to bending and torsion stress. In most investigations it revealed that bending stress is much serve than torsional stress, therefore the probability criteria for the bending state would be higher compared to the torsion state. A statistical comparison between the developed Markov Chain Model and field data was done to observe the percentage of error. The reliability analysis and prediction was derived and illustrated from the Markov Chain Model were shown in the Weibull probability and cumulative distribution function, hazard rate and reliability curve and the bathtub curve. It can be concluded that Markov Chain Model has the ability to generate near similar data with minimal percentage of error and for a practical application; the proposed model provides a good accuracy in determining the reliability for the crankshaft under mixed mode loading

Adjoint sensitivity analysis of dynamic reliability models based on Markov chains - I: Theory

International Nuclear Information System (INIS)

Cacuci, D. G.; Cacuci, D. G.; Ionescu-Bujor, M.

2008-01-01

The development of the adjoint sensitivity analysis procedure (ASAP) for generic dynamic reliability models based on Markov chains is presented, together with applications of this procedure to the analysis of several systems of increasing complexity. The general theory is presented in Part I of this work and is accompanied by a paradigm application to the dynamic reliability analysis of a simple binary component, namely a pump functioning on an 'up/down' cycle until it fails irreparably. This paradigm example admits a closed form analytical solution, which permits a clear illustration of the main characteristics of the ASAP for Markov chains. In particular, it is shown that the ASAP for Markov chains presents outstanding computational advantages over other procedures currently in use for sensitivity and uncertainty analysis of the dynamic reliability of large-scale systems. This conclusion is further underscored by the large-scale applications presented in Part II. (authors)

Adjoint sensitivity analysis of dynamic reliability models based on Markov chains - I: Theory

Energy Technology Data Exchange (ETDEWEB)

Cacuci, D. G. [Commiss Energy Atom, Direct Energy Nucl, Saclay, (France); Cacuci, D. G. [Univ Karlsruhe, Inst Nucl Technol and Reactor Safety, D-76021 Karlsruhe, (Germany); Ionescu-Bujor, M. [Forschungszentrum Karlsruhe, Fus Program, D-76021 Karlsruhe, (Germany)

2008-07-01

The development of the adjoint sensitivity analysis procedure (ASAP) for generic dynamic reliability models based on Markov chains is presented, together with applications of this procedure to the analysis of several systems of increasing complexity. The general theory is presented in Part I of this work and is accompanied by a paradigm application to the dynamic reliability analysis of a simple binary component, namely a pump functioning on an 'up/down' cycle until it fails irreparably. This paradigm example admits a closed form analytical solution, which permits a clear illustration of the main characteristics of the ASAP for Markov chains. In particular, it is shown that the ASAP for Markov chains presents outstanding computational advantages over other procedures currently in use for sensitivity and uncertainty analysis of the dynamic reliability of large-scale systems. This conclusion is further underscored by the large-scale applications presented in Part II. (authors)

Risk and reliability analysis theory and applications : in honor of Prof. Armen Der Kiureghian

CERN Document Server

2017-01-01

This book presents a unique collection of contributions from some of the foremost scholars in the field of risk and reliability analysis. Combining the most advanced analysis techniques with practical applications, it is one of the most comprehensive and up-to-date books available on risk-based engineering. All the fundamental concepts needed to conduct risk and reliability assessments are covered in detail, providing readers with a sound understanding of the field and making the book a powerful tool for students and researchers alike. This book was prepared in honor of Professor Armen Der Kiureghian, one of the fathers of modern risk and reliability analysis.

Summary of the preparation of methodology for digital system reliability analysis for PSA purposes

International Nuclear Information System (INIS)

Hustak, S.; Babic, P.

2001-12-01

The report is structured as follows: Specific features of and requirements for the digital part of NPP Instrumentation and Control (I and C) systems (Computer-controlled digital technologies and systems of the NPP I and C system; Specific types of digital technology failures and preventive provisions; Reliability requirements for the digital parts of I and C systems; Safety requirements for the digital parts of I and C systems; Defence-in-depth). Qualitative analyses of NPP I and C system reliability and safety (Introductory system analysis; Qualitative requirements for and proof of NPP I and C system reliability and safety). Quantitative reliability analyses of the digital parts of I and C systems (Selection of a suitable quantitative measure of digital system reliability; Selected qualitative and quantitative findings regarding digital system reliability; Use of relations among the occurrences of the various types of failure). Mathematical section in support of the calculation of the various types of indices (Boolean reliability models, Markovian reliability models). Example of digital system analysis (Description of a selected protective function and the relevant digital part of the I and C system; Functional chain examined, its components and fault tree). (P.A.)

Data collection on the unit control room simulator as a method of operator reliability analysis

International Nuclear Information System (INIS)

Holy, J.

1998-01-01

The report consists of the following chapters: (1) Probabilistic assessment of nuclear power plant operation safety and human factor reliability analysis; (2) Simulators and simulations as human reliability analysis tools; (3) DOE project for using the collection and analysis of data from the unit control room simulator in human factor reliability analysis at the Paks nuclear power plant; (4) General requirements for the organization of the simulator data collection project; (5) Full-scale simulator at the Nuclear Power Plants Research Institute in Trnava, Slovakia, used as a training means for operators of the Dukovany NPP; (6) Assessment of the feasibility of quantification of important human actions modelled within a PSA study by employing simulator data analysis; (7) Assessment of the feasibility of using the various exercise topics for the quantification of the PSA model; (8) Assessment of the feasibility of employing the simulator in the analysis of the individual factors affecting the operator's activity; and (9) Examples of application of statistical methods in the analysis of the human reliability factor. (P.A.)

Perceived risk and benefits of e-cigarette use among college students.

Science.gov (United States)

Copeland, Amy L; Peltier, MacKenzie R; Waldo, Krystal

2017-08-01

Recent data demonstrates that the use of e-cigarettes is growing, especially among college students and young adults. This trend is increasingly problematic, as many of these individuals report never using traditional tobacco cigarettes, but nevertheless are using e-cigarettes. The present study sought to develop the Risks and Benefits of E-cigarettes (RABE) questionnaire to assess the perceptions about e-cigarette use among college students. College students (N=734) completed the RABE via online survey. Principal components analysis yielded two reliable scales representing perceptions about e-cigarette use. Based on the two-factor solution, subscales were named according to item content. The resulting 30 items demonstrated excellent internal consistency (Risks scale α=0.92; Benefits scale α=0.89). Subsequent confirmatory factor analysis generally supported the 2-factor structure. As an initial measure of construct validity, scale scores were compared across smoking status groups. Smoking status groups were defined by the following: "e-cigarette users" were current daily users of e-cigarettes, "conventional smokers" were daily traditional cigarette users, and "dual users" were individuals who used both e-cigarettes and traditional cigarettes daily. Scale scores for perceived Benefits of e-cigarette use differed significantly across groups (pe-cigarette use. Scale scores for perceived Risks of e-cigarette use across smoking status groups did not significantly differ. The present results indicate that the RABE is a reliable instrument to measure college student's perceived risks and benefits of e-cigarettes. Copyright © 2017 Elsevier Ltd. All rights reserved.

Wind Turbine Drivetrain Reliability Collaborative Workshop: A Recap

Energy Technology Data Exchange (ETDEWEB)

Keller, Jonathan [National Renewable Energy Lab. (NREL), Golden, CO (United States); Sheng, Shuangwen [National Renewable Energy Lab. (NREL), Golden, CO (United States); Cotrell, Jason [National Renewable Energy Lab. (NREL), Golden, CO (United States); Greco, Aaron [Argonne National Lab. (ANL), Argonne, IL (United States)

2016-08-01

The Wind Turbine Drivetrain Reliability Collaborative Workshop was convened by the National Renewable Energy Laboratory (NREL), Argonne National Laboratory, and the U.S. Department of Energy to explore the state of the art in wind turbine drivetrain mechanical system reliability as well as research and development (R&D) challenges that if solved could have significant benefits. The workshop was held at the Research Support Facility on NREL's main campus in Golden, Colorado, from February 16-17, 2016. More than 120 attendees participated from industry, academia, and government. Plenary presentations covered wind turbine drivetrain design, testing, and analysis; tribology -- the science and engineering of interacting surfaces in relative motion -- and failure modes; and condition monitoring and data analytics. In addition to the presentations, workshops were held in each of these areas to discuss R&D challenges. This report serves as a summary of the presentations, workshops, and conclusions on R&D challenges in wind turbine drivetrain reliability.

The design and use of reliability data base with analysis tool

Energy Technology Data Exchange (ETDEWEB)

Doorepall, J.; Cooke, R.; Paulsen, J.; Hokstadt, P.

1996-06-01

With the advent of sophisticated computer tools, it is possible to give a distributed population of users direct access to reliability component operational histories. This allows the user a greater freedom in defining statistical populations of components and selecting failure modes. However, the reliability data analyst`s current analytical instrumentarium is not adequate for this purpose. The terminology used in organizing and gathering reliability data is standardized, and the statistical methods used in analyzing this data are not always suitably chosen. This report attempts to establish a baseline with regard to terminology and analysis methods, to support the use of a new analysis tool. It builds on results obtained in several projects for the ESTEC and SKI on the design of reliability databases. Starting with component socket time histories, we identify a sequence of questions which should be answered prior to the employment of analytical methods. These questions concern the homogeneity and stationarity of (possible dependent) competing failure modes and the independence of competing failure modes. Statistical tests, some of them new, are proposed for answering these questions. Attention is given to issues of non-identifiability of competing risk and clustering of failure-repair events. These ideas have been implemented in an analysis tool for grazing component socket time histories, and illustrative results are presented. The appendix provides background on statistical tests and competing failure modes. (au) 4 tabs., 17 ills., 61 refs.

The design and use of reliability data base with analysis tool

International Nuclear Information System (INIS)

Doorepall, J.; Cooke, R.; Paulsen, J.; Hokstadt, P.

1996-06-01

With the advent of sophisticated computer tools, it is possible to give a distributed population of users direct access to reliability component operational histories. This allows the user a greater freedom in defining statistical populations of components and selecting failure modes. However, the reliability data analyst's current analytical instrumentarium is not adequate for this purpose. The terminology used in organizing and gathering reliability data is standardized, and the statistical methods used in analyzing this data are not always suitably chosen. This report attempts to establish a baseline with regard to terminology and analysis methods, to support the use of a new analysis tool. It builds on results obtained in several projects for the ESTEC and SKI on the design of reliability databases. Starting with component socket time histories, we identify a sequence of questions which should be answered prior to the employment of analytical methods. These questions concern the homogeneity and stationarity of (possible dependent) competing failure modes and the independence of competing failure modes. Statistical tests, some of them new, are proposed for answering these questions. Attention is given to issues of non-identifiability of competing risk and clustering of failure-repair events. These ideas have been implemented in an analysis tool for grazing component socket time histories, and illustrative results are presented. The appendix provides background on statistical tests and competing failure modes. (au) 4 tabs., 17 ills., 61 refs

Microgrid Design Analysis Using Technology Management Optimization and the Performance Reliability Model

Energy Technology Data Exchange (ETDEWEB)

Stamp, Jason E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Eddy, John P. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Jensen, Richard P. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Munoz-Ramos, Karina [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2016-01-01

Microgrids are a focus of localized energy production that support resiliency, security, local con- trol, and increased access to renewable resources (among other potential benefits). The Smart Power Infrastructure Demonstration for Energy Reliability and Security (SPIDERS) Joint Capa- bility Technology Demonstration (JCTD) program between the Department of Defense (DOD), Department of Energy (DOE), and Department of Homeland Security (DHS) resulted in the pre- liminary design and deployment of three microgrids at military installations. This paper is focused on the analysis process and supporting software used to determine optimal designs for energy surety microgrids (ESMs) in the SPIDERS project. There are two key pieces of software, an ex- isting software application developed by Sandia National Laboratories (SNL) called Technology Management Optimization (TMO) and a new simulation developed for SPIDERS called the per- formance reliability model (PRM). TMO is a decision support tool that performs multi-objective optimization over a mixed discrete/continuous search space for which the performance measures are unrestricted in form. The PRM is able to statistically quantify the performance and reliability of a microgrid operating in islanded mode (disconnected from any utility power source). Together, these two software applications were used as part of the ESM process to generate the preliminary designs presented by SNL-led DOE team to the DOD. Acknowledgements Sandia National Laboratories and the SPIDERS technical team would like to acknowledge the following for help in the project: * Mike Hightower, who has been the key driving force for Energy Surety Microgrids * Juan Torres and Abbas Akhil, who developed the concept of microgrids for military instal- lations * Merrill Smith, U.S. Department of Energy SPIDERS Program Manager * Ross Roley and Rich Trundy from U.S. Pacific Command * Bill Waugaman and Bill Beary from U.S. Northern Command * Tarek Abdallah, Melanie

Reliability analysis of component-level redundant topologies for solid-state fault current limiter

Science.gov (United States)

Farhadi, Masoud; Abapour, Mehdi; Mohammadi-Ivatloo, Behnam

2018-04-01

Experience shows that semiconductor switches in power electronics systems are the most vulnerable components. One of the most common ways to solve this reliability challenge is component-level redundant design. There are four possible configurations for the redundant design in component level. This article presents a comparative reliability analysis between different component-level redundant designs for solid-state fault current limiter. The aim of the proposed analysis is to determine the more reliable component-level redundant configuration. The mean time to failure (MTTF) is used as the reliability parameter. Considering both fault types (open circuit and short circuit), the MTTFs of different configurations are calculated. It is demonstrated that more reliable configuration depends on the junction temperature of the semiconductor switches in the steady state. That junction temperature is a function of (i) ambient temperature, (ii) power loss of the semiconductor switch and (iii) thermal resistance of heat sink. Also, results' sensitivity to each parameter is investigated. The results show that in different conditions, various configurations have higher reliability. The experimental results are presented to clarify the theory and feasibility of the proposed approaches. At last, levelised costs of different configurations are analysed for a fair comparison.

Application of reliability analysis methods to the comparison of two safety circuits

International Nuclear Information System (INIS)

Signoret, J.-P.

1975-01-01

Two circuits of different design, intended for assuming the ''Low Pressure Safety Injection'' function in PWR reactors are analyzed using reliability methods. The reliability analysis of these circuits allows the failure trees to be established and the failure probability derived. The dependence of these results on test use and maintenance is emphasized as well as critical paths. The great number of results obtained may allow a well-informed choice taking account of the reliability wanted for the type of circuits [fr

Signal Quality Outage Analysis for Ultra-Reliable Communications in Cellular Networks

DEFF Research Database (Denmark)

Gerardino, Guillermo Andrés Pocovi; Alvarez, Beatriz Soret; Lauridsen, Mads

2015-01-01

Ultra-reliable communications over wireless will open the possibility for a wide range of novel use cases and applications. In cellular networks, achieving reliable communication is challenging due to many factors, particularly the fading of the desired signal and the interference. In this regard......, we investigate the potential of several techniques to combat these main threats. The analysis shows that traditional microscopic multiple-input multiple-output schemes with 2x2 or 4x4 antenna configurations are not enough to fulfil stringent reliability requirements. It is revealed how such antenna...... schemes must be complemented with macroscopic diversity as well as interference management techniques in order to ensure the necessary SINR outage performance. Based on the obtained performance results, it is discussed which of the feasible options fulfilling the ultra-reliable criteria are most promising...

An application of the fault tree analysis for the power system reliability estimation

International Nuclear Information System (INIS)

Volkanovski, A.; Cepin, M.; Mavko, B.

2007-01-01

The power system is a complex system with its main function to produce, transfer and provide consumers with electrical energy. Combinations of failures of components in the system can result in a failure of power delivery to certain load points and in some cases in a full blackout of power system. The power system reliability directly affects safe and reliable operation of nuclear power plants because the loss of offsite power is a significant contributor to the core damage frequency in probabilistic safety assessments of nuclear power plants. The method, which is based on the integration of the fault tree analysis with the analysis of the power flows in the power system, was developed and implemented for power system reliability assessment. The main contributors to the power system reliability are identified, both quantitatively and qualitatively. (author)

Cost-benefit analysis for waste segregation at Lawrence Livermore National Laboratory

International Nuclear Information System (INIS)

1992-02-01

This report presents a cost-benefit analysis for the segregation of mixed, hazardous, and nonhazardous wastes at Lawrence Livermore National Laboratory (LLNL). The cost-benefit analysis was conducted to determine if current waste segregation practices and additional candidates for waste segregation at LLNL might have the potential for significant waste source reduction and annual savings in treatment and disposal costs. In the following cost-benefit analysis, capital costs and recurring costs of waste segregation practices are compared to the economic benefits of savings in treatment and disposal costs. Indirect or overhead costs associated with these wastes are not available and have not been included. Not considered are additional benefits of waste segregation such as decreased potential for liability to LLNL for adverse environmental effects, improved worker safety, and enhanced LLNL image within the community because of environmental improvement. The economic evaluations in this report are presented on a Lab-wide basis. All hazardous wastes generated by a program are turned over to the Hazardous Waste Management (HWM) group, which is responsible for the storage, treatment, or disposal of these wastes and funded funded directly for this work

Maintenance management of railway infrastructures based on reliability analysis

International Nuclear Information System (INIS)

Macchi, Marco; Garetti, Marco; Centrone, Domenico; Fumagalli, Luca; Piero Pavirani, Gian

2012-01-01

Railway infrastructure maintenance plays a crucial role for rail transport. It aims at guaranteeing safety of operations and availability of railway tracks and related equipment for traffic regulation. Moreover, it is one major cost for rail transport operations. Thus, the increased competition in traffic market is asking for maintenance improvement, aiming at the reduction of maintenance expenditures while keeping the safety of operations. This issue is addressed by the methodology presented in the paper. The first step of the methodology consists of a family-based approach for the equipment reliability analysis; its purpose is the identification of families of railway items which can be given the same reliability targets. The second step builds the reliability model of the railway system for identifying the most critical items, given a required service level for the transportation system. The two methods have been implemented and tested in practical case studies, in the context of Rete Ferroviaria Italiana, the Italian public limited company for railway transportation.

Solid Rocket Booster Large Main and Drogue Parachute Reliability Analysis

Science.gov (United States)

Clifford, Courtenay B.; Hengel, John E.

2009-01-01

The parachutes on the Space Transportation System (STS) Solid Rocket Booster (SRB) are the means for decelerating the SRB and allowing it to impact the water at a nominal vertical velocity of 75 feet per second. Each SRB has one pilot, one drogue, and three main parachutes. About four minutes after SRB separation, the SRB nose cap is jettisoned, deploying the pilot parachute. The pilot chute then deploys the drogue parachute. The drogue chute provides initial deceleration and proper SRB orientation prior to frustum separation. At frustum separation, the drogue pulls the frustum from the SRB and allows the main parachutes that are mounted in the frustum to unpack and inflate. These chutes are retrieved, inspected, cleaned, repaired as needed, and returned to the flight inventory and reused. Over the course of the Shuttle Program, several improvements have been introduced to the SRB main parachutes. A major change was the replacement of the small (115 ft. diameter) main parachutes with the larger (136 ft. diameter) main parachutes. Other modifications were made to the main parachutes, main parachute support structure, and SRB frustum to eliminate failure mechanisms, improve damage tolerance, and improve deployment and inflation characteristics. This reliability analysis is limited to the examination of the SRB Large Main Parachute (LMP) and drogue parachute failure history to assess the reliability of these chutes. From the inventory analysis, 68 Large Main Parachutes were used in 651 deployments, and 7 chute failures occurred in the 651 deployments. Logistic regression was used to analyze the LMP failure history, and it showed that reliability growth has occurred over the period of use resulting in a current chute reliability of R = .9983. This result was then used to determine the reliability of the 3 LMPs on the SRB, when all must function. There are 29 drogue parachutes that were used in 244 deployments, and no in-flight failures have occurred. Since there are no

Analysis of Employee Benefits

OpenAIRE

Burešová, Lenka

2013-01-01

The target of this bachelor thesis is to analyze employee benefits from the perspective of employees and to employers suggest possible ideas to improve their provision. The work is divided into two parts: theoretical and practical. The theoretical part describes the overal remuneration of employees, payroll system and employee benefits. Benefits are included in the remuneration system, broken and some of them are defined. The practical part presents a survey among employees in the Czech Repub...

A Cost to Benefit Analysis of a Next Generation Electric Power Distribution System

Science.gov (United States)

Raman, Apurva

This thesis provides a cost to benefit analysis of the proposed next generation of distribution systems- the Future Renewable Electric Energy Distribution Management (FREEDM) system. With the increasing penetration of renewable energy sources onto the grid, it becomes necessary to have an infrastructure that allows for easy integration of these resources coupled with features like enhanced reliability of the system and fast protection from faults. The Solid State Transformer (SST) and the Fault Isolation Device (FID) make for the core of the FREEDM system and have huge investment costs. Some key features of the FREEDM system include improved power flow control, compact design and unity power factor operation. Customers may observe a reduction in the electricity bill by a certain fraction for using renewable sources of generation. There is also a possibility of huge subsidies given to encourage use of renewable energy. This thesis is an attempt to quantify the benefits offered by the FREEDM system in monetary terms and to calculate the time in years required to gain a return on investments made. The elevated cost of FIDs needs to be justified by the advantages they offer. The result of different rates of interest and how they influence the payback period is also studied. The payback periods calculated are observed for viability. A comparison is made between the active power losses on a certain distribution feeder that makes use of distribution level magnetic transformers versus one that makes use of SSTs. The reduction in the annual active power losses in the case of the feeder using SSTs is translated onto annual savings in terms of cost when compared to the conventional case with magnetic transformers. Since the FREEDM system encourages operation at unity power factor, the need for installing capacitor banks for improving the power factor is eliminated and this reflects in savings in terms of cost. The FREEDM system offers enhanced reliability when compared to a

A methodology for strain-based fatigue reliability analysis

International Nuclear Information System (INIS)

Zhao, Y.X.

2000-01-01

A significant scatter of the cyclic stress-strain (CSS) responses should be noted for a nuclear reactor material, 1Cr18Ni9Ti pipe-weld metal. Existence of the scatter implies that a random cyclic strain applied history will be introduced under any of the loading modes even a deterministic loading history. A non-conservative evaluation might be given in the practice without considering the scatter. A methodology for strain-based fatigue reliability analysis, which has taken into account the scatter, is developed. The responses are approximately modeled by probability-based CSS curves of Ramberg-Osgood relation. The strain-life data are modeled, similarly, by probability-based strain-life curves of Coffin-Manson law. The reliability assessment is constructed by considering interference of the random fatigue strain applied and capacity histories. Probability density functions of the applied and capacity histories are analytically given. The methodology could be conveniently extrapolated to the case of deterministic CSS relation as the existent methods did. Non-conservative evaluation of the deterministic CSS relation and availability of present methodology have been indicated by an analysis of the material test results

Intra-observer reliability and agreement of manual and digital orthodontic model analysis.

Science.gov (United States)

Koretsi, Vasiliki; Tingelhoff, Linda; Proff, Peter; Kirschneck, Christian

2018-01-23

Digital orthodontic model analysis is gaining acceptance in orthodontics, but its reliability is dependent on the digitalisation hardware and software used. We thus investigated intra-observer reliability and agreement / conformity of a particular digital model analysis work-flow in relation to traditional manual plaster model analysis. Forty-eight plaster casts of the upper/lower dentition were collected. Virtual models were obtained with orthoX®scan (Dentaurum) and analysed with ivoris®analyze3D (Computer konkret). Manual model analyses were done with a dial caliper (0.1 mm). Common parameters were measured on each plaster cast and its virtual counterpart five times each by an experienced observer. We assessed intra-observer reliability within method (ICC), agreement/conformity between methods (Bland-Altman analyses and Lin's concordance correlation), and changing bias (regression analyses). Intra-observer reliability was substantial within each method (ICC ≥ 0.7), except for five manual outcomes (12.8 per cent). Bias between methods was statistically significant, but less than 0.5 mm for 87.2 per cent of the outcomes. In general, larger tooth sizes were measured digitally. Total difference maxilla and mandible had wide limits of agreement (-3.25/6.15 and -2.31/4.57 mm), but bias between methods was mostly smaller than intra-observer variation within each method with substantial conformity of manual and digital measurements in general. No changing bias was detected. Although both work-flows were reliable, the investigated digital work-flow proved to be more reliable and yielded on average larger tooth sizes. Averaged differences between methods were within 0.5 mm for directly measured outcomes but wide ranges are expected for some computed space parameters due to cumulative error. © The Author 2017. Published by Oxford University Press on behalf of the European Orthodontic Society. All rights reserved. For permissions, please email: journals.permissions@oup.com

A fast approximation method for reliability analysis of cold-standby systems

International Nuclear Information System (INIS)

Wang, Chaonan; Xing, Liudong; Amari, Suprasad V.

2012-01-01

Analyzing reliability of large cold-standby systems has been a complicated and time-consuming task, especially for systems with components having non-exponential time-to-failure distributions. In this paper, an approximation model, which is based on the central limit theorem, is presented for the reliability analysis of binary cold-standby systems. The proposed model can estimate the reliability of large cold-standby systems with binary-state components having arbitrary time-to-failure distributions in an efficient and easy way. The accuracy and efficiency of the proposed method are illustrated using several different types of distributions for both 1-out-of-n and k-out-of-n cold-standby systems.

Integrating Life-cycle Assessment into Transport Cost-benefit Analysis

DEFF Research Database (Denmark)

Manzo, Stefano; Salling, Kim Bang

2016-01-01

Traditional transport Cost-Benefit Analysis (CBA) commonly ignores the indirect environmental impacts of an infrastructure project deriving from the overall life-cycle of the different project components. Such indirect impacts are instead of key importance in order to assess the long......-term sustainability of a transport infrastructure project. In the present study we suggest to overcome this limit by combining a conventional life-cycle assessment approach with standard transport cost-benefit analysis. The suggested methodology is tested upon a case study project related to the construction of a new...... fixed link across the Roskilde fjord in Frederikssund (Denmark). The results are then compared with those from a standard CBA framework. The analysis shows that indirect environmental impacts represent a relevant share of the estimated costs of the project, clearly affecting the final project evaluation...

Reliability data banks

International Nuclear Information System (INIS)

Cannon, A.G.; Bendell, A.

1991-01-01

Following an introductory chapter on Reliability, what is it, why it is needed, how it is achieved and measured, the principles of reliability data bases and analysis methodologies are the subject of the next two chapters. Achievements due to the development of data banks are mentioned for different industries in the next chapter, FACTS, a comprehensive information system for industrial safety and reliability data collection in process plants are covered next. CREDO, the Central Reliability Data Organization is described in the next chapter and is indexed separately, as is the chapter on DANTE, the fabrication reliability Data analysis system. Reliability data banks at Electricite de France and IAEA's experience in compiling a generic component reliability data base are also separately indexed. The European reliability data system, ERDS, and the development of a large data bank come next. The last three chapters look at 'Reliability data banks, - friend foe or a waste of time'? and future developments. (UK)

A framework for intelligent reliability centered maintenance analysis

International Nuclear Information System (INIS)

Cheng Zhonghua; Jia Xisheng; Gao Ping; Wu Su; Wang Jianzhao

2008-01-01

To improve the efficiency of reliability-centered maintenance (RCM) analysis, case-based reasoning (CBR), as a kind of artificial intelligence (AI) technology, was successfully introduced into RCM analysis process, and a framework for intelligent RCM analysis (IRCMA) was studied. The idea for IRCMA is based on the fact that the historical records of RCM analysis on similar items can be referenced and used for the current RCM analysis of a new item. Because many common or similar items may exist in the analyzed equipment, the repeated tasks of RCM analysis can be considerably simplified or avoided by revising the similar cases in conducting RCM analysis. Based on the previous theory studies, an intelligent RCM analysis system (IRCMAS) prototype was developed. This research has focused on the description of the definition, basic principles as well as a framework of IRCMA, and discussion of critical techniques in the IRCMA. Finally, IRCMAS prototype is presented based on a case study

Reliability analysis of digital safety systems at nuclear power plants

International Nuclear Information System (INIS)

Sopira Vladimir; Kovacs, Zoltan

2015-01-01

Reliability analysis of digital reactor protection systems built on the basis of TELEPERM XS is described, and experience gained by the Slovak RELKO company during the past 20 years in this domain is highlighted. (orig.)

Reliability analysis of protection systems in NPP applying fault-tree analysis method

International Nuclear Information System (INIS)

Bokor, J.; Gaspar, P.; Hetthessy, J.; Szabo, G.

1998-01-01

This paper demonstrates the applicability and limits of dependability analysis in nuclear power plants (NPPS) based on the reactor protection refurbishment project (RRP) in NPP Paks. This paper illustrates case studies from the reliability analysis for NPP Paks. It also investigates the solutions for the connection between the data acquisition and subsystem control units (TSs) and the voter units (VTs), it analyzes the influence of the voting in the VT computer level, it studies the effects of the testing procedures to the dependability parameters. (author)

A cost-benefit analysis for materials management information systems.

Science.gov (United States)

Slapak-Iacobelli, L; Wilde, A H

1993-02-01

The cost-benefit analysis provided the system planners with valuable information that served many purposes. It answered the following questions: Why was the CCF undertaking this project? What were the alternatives? How much was it going to cost? And what was the expected outcome? The process of developing cost-benefit the document kept the project team focused. It also motivated them to involve additional individuals from materials management and accounts payable in its development. A byproduct of this involvement was buy-in and commitment to the project by everyone in these areas. Consequently, the project became a team effort championed by many and not just one. We were also able to introduce two new information system processes: 1) a management review process with goals and anticipated results, and 2) a quality assurance process that ensured the CCF had a better product in the end. The cost-benefit analysis provided a planning tool that assisted in successful implementation of an integrated materials management information system.

Study on reliability analysis based on multilevel flow models and fault tree method

International Nuclear Information System (INIS)

Chen Qiang; Yang Ming

2014-01-01

Multilevel flow models (MFM) and fault tree method describe the system knowledge in different forms, so the two methods express an equivalent logic of the system reliability under the same boundary conditions and assumptions. Based on this and combined with the characteristics of MFM, a method mapping MFM to fault tree was put forward, thus providing a way to establish fault tree rapidly and realizing qualitative reliability analysis based on MFM. Taking the safety injection system of pressurized water reactor nuclear power plant as an example, its MFM was established and its reliability was analyzed qualitatively. The analysis result shows that the logic of mapping MFM to fault tree is correct. The MFM is easily understood, created and modified. Compared with the traditional fault tree analysis, the workload is greatly reduced and the modeling time is saved. (authors)

A comparison between fault tree analysis and reliability graph with general gates

International Nuclear Information System (INIS)

Kim, Man Cheol; Seong, Poong Hyun; Jung, Woo Sik

2004-01-01

Currently, level-1 probabilistic safety assessment (PSA) is performed on the basis of event tree analysis and fault tree analysis. Kim and Seong developed a new method for system reliability analysis named reliability graph with general gates (RGGG). The RGGG is an extension of conventional reliability graph, and it utilizes the transformation of system structures to equivalent Bayesian networks for quantitative calculation. The RGGG is considered to be intuitive and easy-to-use while as powerful as fault tree analysis. As an example, Kim and Seong already showed that the Bayesian network model for digital plant protection system (DPPS), which is transformed from the RGGG model for DPPS, can be shown in 1 page, while the fault tree model for DPPS consists of 64 pages of fault trees. Kim and Seong also insisted that Bayesian network model for DPPS is more intuitive because the one-to-one matching between each node in the Bayesian network model and an actual component of DPPS is possible. In this paper, we are going to give a comparison between fault tree analysis and the RGGG method with two example systems. The two example systems are the recirculation of in Korean standard nuclear power plants (KSNP) and the fault tree model developed by Rauzy

Reliability analysis of containment isolation systems

International Nuclear Information System (INIS)

Pelto, P.J.; Counts, C.A.

1984-06-01

The Pacific Northwest Laboratory (PNL) is reviewing available information on containment systems design, operating experience, and related research as part of a project being conducted by the Division of Systems Integration, US Nuclear Regulatory Commission. The basic objective of this work is to collect and consolidate data relevant to assessing the functional performance of containment isolation systems and to use this data to the extent possible to characterize containment isolation system reliability for selected reference designs. This paper summarizes the results from initial efforts which focused on collection of data from available documents and briefly describes detailed review and analysis efforts which commenced recently. 5 references

Reliability analysis of pipelines and pressure vessels at nuclear power plants

International Nuclear Information System (INIS)

Klemin, A.I.; Shiverskij, E.A.

1979-01-01

Reliability analysis of pipelines and pressure vessels at NPP is given. The main causes and failure mechanisms of these elements, the ways of reliability improvement and preventing of great damages are considered. The reliability estimation methods both according to the statistical operation data and under the conditions of absence of failure statistics are given. The main characteristics and actual reliability factors of pipelines and pressure vessels of three home NPP: the first in the world NPP, VK-50 and Beloyarsk NPP, are presented. From the start-up there were practically no failures of the pipelines and pressure vessels at the VK-50 pilot installation. The analysis of the operation experience of the first and second blocks of the Beloyarsk NPP, as well as the first in the world NPP, shows that the most part of failures of the pipelines and pressure vessels of these energy blocks with the channel reactors is connected with the coolant leakage at minority pipelines of a small diameter. The most part of failures at individual pipelines of the first and second blocks of the Beloyarsk NPP are connected with the leakages of stuffing boxes of switching off devices. It is noted that serious failures of large pipelines and pressure vessels at all home NPP under operation have not been observed

Is Job Sharing Worthwhile? A Cost-Benefit Analysis in UK Universities.

Science.gov (United States)

Harris, Geoff

1997-01-01

Data from a survey of personnel directors in United Kingdom universities were used to conduct a cost-benefit analysis of job sharing from the institutions' perspective. Results show a 5% rise in productivity would raise the ratio of benefits to cost to 14.3 to 1. Retention of staff, reduction of stress, and reduced unemployment are also benefits.…

Human reliability analysis of Lingao Nuclear Power Station

International Nuclear Information System (INIS)

Zhang Li; Huang Shudong; Yang Hong; He Aiwu; Huang Xiangrui; Zheng Tao; Su Shengbing; Xi Haiying

2001-01-01

The necessity of human reliability analysis (HRA) of Lingao Nuclear Power Station are analyzed, and the method and operation procedures of HRA is briefed. One of the human factors events (HFE) is analyzed in detail and some questions of HRA are discussed. The authors present the analytical results of 61 HFEs, and make a brief introduction of HRA contribution to Lingao Nuclear Power Station

Spatial reliability analysis of a wind turbine blade cross section subjected to multi-axial extreme loading

DEFF Research Database (Denmark)

Dimitrov, Nikolay Krasimirov; Bitsche, Robert; Blasques, José Pedro Albergaria Amaral

2017-01-01

This paper presents a methodology for structural reliability analysis of wind turbine blades. The study introduces several novel elements by taking into account loading direction using a multiaxial probabilistic load model, considering random material strength, spatial correlation between material...... properties, progressive material failure, and system reliability effects. An example analysis of reliability against material failure is demonstrated for a blade cross section. Based on the study we discuss the implications of using a system reliability approach, the effect of spatial correlation length......, type of material degradation algorithm, and reliability methods on the system failure probability, as well as the main factors that have an influence on the reliability. (C) 2017 Elsevier Ltd. All rights reserved....

Reliability Information Analysis Center 1st Quarter 2007, Technical Area Task (TAT) Report

Science.gov (United States)

2007-02-05

Library or [twField/Test 217Plus Ally w/ a.romtu DAAData Experience Data Need t( rdito Trqnd • s aa(Model) develol analisis Mappng & ANLED217Plu...of collected reliability data and have discovered that even with sparse data, analysis of the data shows clustering of reliability data by equipment...intended search target. Conceptually cluster discovered data to allow more detailed analysis by equipment type. For example, it may be useful to

Diakoptical reliability analysis of transistorized systems

International Nuclear Information System (INIS)

Kontoleon, J.M.; Lynn, J.W.; Green, A.E.

1975-01-01

Limitations both on high-speed core availability and computation time required for assessing the reliability of large-sized and complex electronic systems, such as used for the protection of nuclear reactors, are very serious restrictions which continuously confront the reliability analyst. Diakoptic methods simplify the solution of the electrical-network problem by subdividing a given network into a number of independent subnetworks and then interconnecting the solutions of these smaller parts by a systematic process involving transformations based on connection-matrix elements associated with the interconnecting links. However, the interconnection process is very complicated and it may be used only if the original system has been cut in such a manner that a relation can be established between the constraints appearing at both sides of the cut. Also, in dealing with transistorized systems, one of the difficulties encountered is that of modelling adequately their performance under various operating conditions, since their parameters are strongly affected by the imposed voltage and current levels. In this paper a new interconnection approach is presented which may be of use in the reliability analysis of large-sized transistorized systems. This is based on the partial optimization of the subdivisions of the torn network as well as on the optimization of the torn paths. The solution of the subdivisions is based on the principles of algebraic topology, with an algebraic structure relating the physical variables in a topological structure which defines the interconnection of the discrete elements. Transistors, and other nonlinear devices, are modelled using their actual characteristics, under normal and abnormal operating conditions. Use of so-called k factors is made to facilitate accounting for use of electrical stresses. The approach is demonstrated by way of an example. (author)

TRICARE Applied Behavior Analysis (ABA) Benefit: Comparison with Medicaid and Commercial Benefits.

Science.gov (United States)

Maglione, Margaret; Kadiyala, Srikanth; Kress, Amii; Hastings, Jaime L; O'Hanlon, Claire E

2017-01-01

This study compared the Applied Behavior Analysis (ABA) benefit provided by TRICARE as an early intervention for autism spectrum disorder with similar benefits in Medicaid and commercial health insurance plans. The sponsor, the Office of the Under Secretary of Defense for Personnel and Readiness, was particularly interested in how a proposed TRICARE reimbursement rate decrease from $125 per hour to $68 per hour for ABA services performed by a Board Certified Behavior Analyst compared with reimbursement rates (defined as third-party payment to the service provider) in Medicaid and commercial health insurance plans. Information on ABA coverage in state Medicaid programs was collected from Medicaid state waiver databases; subsequently, Medicaid provider reimbursement data were collected from state Medicaid fee schedules. Applied Behavior Analysis provider reimbursement in the commercial health insurance system was estimated using Truven Health MarketScan® data. A weighted mean U.S. reimbursement rate was calculated for several services using cross-state information on the number of children diagnosed with autism spectrum disorder. Locations of potential provider shortages were also identified. Medicaid and commercial insurance reimbursement rates varied considerably across the United States. This project concluded that the proposed $68-per-hour reimbursement rate for services provided by a board certified analyst was more than 25 percent below the U.S. mean.

ANALYSIS OF AVAILABILITY AND RELIABILITY IN RHIC OPERATIONS

International Nuclear Information System (INIS)

PILAT, F.; INGRASSIA, P.; MICHNOFF, R.

2006-01-01

RHIC has been successfully operated for 5 years as a collider for different species, ranging from heavy ions including gold and copper, to polarized protons. We present a critical analysis of reliability data for RHIC that not only identifies the principal factors limiting availability but also evaluates critical choices at design times and assess their impact on present machine performance. RHIC availability data are typical when compared to similar high-energy colliders. The critical analysis of operations data is the basis for studies and plans to improve RHIC machine availability beyond the 50-60% typical of high-energy colliders

ESTIMATING RELIABILITY OF DISTURBANCES IN SATELLITE TIME SERIES DATA BASED ON STATISTICAL ANALYSIS

Directory of Open Access Journals (Sweden)

Z.-G. Zhou

2016-06-01

Full Text Available Normally, the status of land cover is inherently dynamic and changing continuously on temporal scale. However, disturbances or abnormal changes of land cover — caused by such as forest fire, flood, deforestation, and plant diseases — occur worldwide at unknown times and locations. Timely detection and characterization of these disturbances is of importance for land cover monitoring. Recently, many time-series-analysis methods have been developed for near real-time or online disturbance detection, using satellite image time series. However, the detection results were only labelled with “Change/ No change” by most of the present methods, while few methods focus on estimating reliability (or confidence level of the detected disturbances in image time series. To this end, this paper propose a statistical analysis method for estimating reliability of disturbances in new available remote sensing image time series, through analysis of full temporal information laid in time series data. The method consists of three main steps. (1 Segmenting and modelling of historical time series data based on Breaks for Additive Seasonal and Trend (BFAST. (2 Forecasting and detecting disturbances in new time series data. (3 Estimating reliability of each detected disturbance using statistical analysis based on Confidence Interval (CI and Confidence Levels (CL. The method was validated by estimating reliability of disturbance regions caused by a recent severe flooding occurred around the border of Russia and China. Results demonstrated that the method can estimate reliability of disturbances detected in satellite image with estimation error less than 5% and overall accuracy up to 90%.

Reliability analysis of neutron flux monitoring system for PFBR

International Nuclear Information System (INIS)

Rajesh, M.G.; Bhatnagar, P.V.; Das, D.; Pithawa, C.K.; Vinod, Gopika; Rao, V.V.S.S.

2010-01-01

The Neutron Flux Monitoring System (NFMS) measures reactor power, rate of change of power and reactivity changes in the core in all states of operation and shutdown. The system consists of instrument channels that are designed and built to have high reliability. All channels are required to have a Mean Time Between Failures (MTBF) of 150000 hours minimum. Failure Mode and Effects Analysis (FMEA) and failure rate estimation of NFMS channels has been carried out. FMEA is carried out in compliance with MIL-STD-338B. Reliability estimation of the channels is done according to MIL-HDBK-217FN2. Paper discusses the methodology followed for FMEA and failure rate estimation of two safety channels and results. (author)

Re-evaluation of a radiation protection cost benefit analysis study in brachytherapy

International Nuclear Information System (INIS)

Broek, J.G. van den; Weatherburn, H.

1994-01-01

This study investigates changes in the NRPB advice concerning cost benefit analysis over the last 10 years by correcting all figures for inflation and applying them to a particular radiation protection example, a previously published case of the introduction of afterloading brachytherapy equipment at the Christie Hospital, Manchester. It has been shown that for this example NRPB advice at one time led to a large cost benefit, at another time led to a large cost deficit and later still it again gives a large cost benefit. Application of cost benefit analysis to decision making in radiation protection is therefore shown to be in need of further investigation and clarification. (author)

Early infant male circumcision: Systematic review, risk-benefit analysis, and progress in policy.

Science.gov (United States)

Morris, Brian J; Kennedy, Sean E; Wodak, Alex D; Mindel, Adrian; Golovsky, David; Schrieber, Leslie; Lumbers, Eugenie R; Handelsman, David J; Ziegler, John B

2017-02-08

To determine whether recent evidence-based United States policies on male circumcision (MC) apply to comparable Anglophone countries, Australia and New Zealand. Articles in 2005 through 2015 were retrieved from PubMed using the keyword "circumcision" together with 36 relevant subtopics. A further PubMed search was performed for articles published in 2016. Searches of the EMBASE and Cochrane databases did not yield additional citable articles. Articles were assessed for quality and those rated 2+ and above according to the Scottish Intercollegiate Grading System were studied further. The most relevant and representative of the topic were included. Bibliographies were examined to retrieve further key references. Randomized controlled trials, recent high quality systematic reviews or meta-analyses (level 1++ or 1+ evidence) were prioritized for inclusion. A risk-benefit analysis of articles rated for quality was performed. For efficiency and reliability, recent randomized controlled trials, meta-analyses, high quality systematic reviews and large well-designed studies were used if available. Internet searches were conducted for other relevant information, including policies and Australian data on claims under Medicare for MC. Evidence-based policy statements by the American Academy of Pediatrics (AAP) and the Centers for Disease Control and Prevention (CDC) support infant and later age male circumcision (MC) as a desirable public health measure. Our systematic review of relevant literature over the past decade yielded 140 journal articles that met our inclusion criteria. Together, these showed that early infant MC confers immediate and lifelong benefits by protecting against urinary tract infections having potential adverse long-term renal effects, phimosis that causes difficult and painful erections and "ballooning" during urination, inflammatory skin conditions, inferior penile hygiene, candidiasis, various sexually transmissible infections in both sexes, genital

Development and psychometric evaluation of the Dialysis patient-perceived Exercise Benefits and Barriers Scale.

Science.gov (United States)

Zheng, Jing; You, Li-Ming; Lou, Tan-Qi; Chen, Nian-Chang; Lai, De-Yuan; Liang, Yan-Yi; Li, Ying-Na; Gu, Ying-Ming; Lv, Shao-Fen; Zhai, Cui-Qiu

2010-02-01

Perceptions of exercise benefits and barriers affect exercise behavior. Because of the clinical course and treatment, dialysis patients differ from the general population in their perceptions of exercise benefits and barriers, especially the latter. At present, no valid instruments for assessing perceived exercise benefits and barriers in dialysis patients are available. Our goal was to develop and test the psychometric properties of the Dialysis patient-perceived Exercise Benefits and Barriers Scale (DPEBBS). A literature review and two focus groups were conducted to generate the initial item pool. An expert panel examined the content validity. Then, 269 Chinese hemodialysis patients were recruited by convenience sampling. Exploratory and confirmatory factor analyses were used to test construct validity. Finally, internal consistency and test-retest reliability were assessed. The expert panel determined that the content validity index was satisfactory. The final 24-item scale consisted of six factors explaining 57% of the total variance in the data. Confirmative factor analysis supported the six-factor structure and a higher-order model. Cronbach's alpha was 0.87 for the total scale, and 0.84 for test-retest reliability. The DPEBBS was a valid and reliable instrument for evaluating dialysis patients' perceived benefits and barriers to exercise. The application value of this scale remains to be investigated by increasing the sample size and evaluating patients undergoing different dialysis modalities and coming from different regions and cultural backgrounds. Copyright 2009 Elsevier Ltd. All rights reserved.

Human Reliability Analysis: session summary

International Nuclear Information System (INIS)

Hall, R.E.

1985-01-01

The use of Human Reliability Analysis (HRA) to identify and resolve human factors issues has significantly increased over the past two years. Today, utilities, research institutions, consulting firms, and the regulatory agency have found a common application of HRA tools and Probabilistic Risk Assessment (PRA). The ''1985 IEEE Third Conference on Human Factors and Power Plants'' devoted three sessions to the discussion of these applications and a review of the insights so gained. This paper summarizes the three sessions and presents those common conclusions that were discussed during the meeting. The paper concludes that session participants supported the use of an adequately documented ''living PRA'' to address human factors issues in design and procedural changes, regulatory compliance, and training and that the techniques can produce cost effective qualitative results that are complementary to more classical human factors methods

Development of the GO-FLOW reliability analysis methodology for nuclear reactor system

International Nuclear Information System (INIS)

Matsuoka, Takeshi; Kobayashi, Michiyuki

1994-01-01

Probabilistic Safety Assessment (PSA) is important in the safety analysis of technological systems and processes, such as, nuclear plants, chemical and petroleum facilities, aerospace systems. Event trees and fault trees are the basic analytical tools that have been most frequently used for PSAs. Several system analysis methods can be used in addition to, or in support of, the event- and fault-tree analysis. The need for more advanced methods of system reliability analysis has grown with the increased complexity of engineered systems. The Ship Research Institute has been developing a new reliability analysis methodology, GO-FLOW, which is a success-oriented system analysis technique, and is capable of evaluating a large system with complex operational sequences. The research has been supported by the special research fund for Nuclear Technology, Science and Technology Agency, from 1989 to 1994. This paper describes the concept of the Probabilistic Safety Assessment (PSA), an overview of various system analysis techniques, an overview of the GO-FLOW methodology, the GO-FLOW analysis support system, procedure of treating a phased mission problem, a function of common cause failure analysis, a function of uncertainty analysis, a function of common cause failure analysis with uncertainty, and printing out system of the results of GO-FLOW analysis in the form of figure or table. Above functions are explained by analyzing sample systems, such as PWR AFWS, BWR ECCS. In the appendices, the structure of the GO-FLOW analysis programs and the meaning of the main variables defined in the GO-FLOW programs are described. The GO-FLOW methodology is a valuable and useful tool for system reliability analysis, and has a wide range of applications. With the development of the total system of the GO-FLOW, this methodology has became a powerful tool in a living PSA. (author) 54 refs

Analysis of Benefits of an Energy Imbalance Market in the NWPP

Energy Technology Data Exchange (ETDEWEB)

Samaan, Nader A.; Bayless, Rich; Symonds, Mark; Nguyen, Tony B.; Jin, Chunlian; Wu, Di; Diao, Ruisheng; Makarov, Yuri V.; Kannberg, Landis D.; Guo, Tao; Dennison-Leonard , Sarah; Goodenough, Mike; Schellberg, Ron; Conger, Sid; Harris, Kevin; Rarity, Matt; Wallace, Steven; Austin, Jamie; Noteboom, Rod; Van Blaricom , Tim; McRunnel, Kim; Apperson, John; Empey, Marshall; Etingov, Pavel V.; Warady, Debra; Brush, Ray; Newkirk, Joshua; Williams, Peter; Landauer, Marv; Owen, Hugh; Morter, Wayne; Haraguchi, Keli; Portouw, Jim; Downey, kathryn; Sorey, Steve; Williams, Stan; Gossa, Teyent; Kalich, Clint; Damiano, Patrick; Macarthur, Clay; Martin, Tom; Hoerner, Joe; Knudsen, Steve; Johnson, Anders; Link, Rick; Holcomb, Dennis

2013-10-18

the NWPP depending on what assumptions are made. The instructions from the MC were to determine a "minimum high confidence" range of potential benefits. The results for the Base Case indicate that the EIM benefits ranged from approximately $40 million to $70 million in annual savings from the operation of an EIM in the NWPP footprint. A number of additional relevant sensitivity cases were performed, including low and high water conditions, low and high natural gas prices, and various flex reserve requirements, resource operations, and amounts of resource capability held back during the preschedule period. Along with the results for the Base Case, the results for these studies yielded EIM benefits that clustered within the range of $70 to $80 million dollars per year with potential benefits ranging from approximately $125 million to as little as $17 million per year. Because the design and operation of an EIM could enable participating Balancing Authorities (BAs) to collectively lower the quantity of resources they must carry to meet within-hour balancing needs, a sensitivity case was also performed to analyze the impact that such reductions might have on the benefits from an EIM. The results for this sensitivity case indicate that such reductions could increase the benefits from the operation of an EIM in the NWPP into the range of approximately $130 million to $160 million per year. Also, a sensitivity case for a WECC-wide EIM was performed with the results indicating that the potential benefits to the NWPP could increase into the range of $197 million to $233 million per year. While there may be potential reliability benefits from the coordinated dispatch process underlying the operation of an EIM, reliability benefits from an EIM were out of the scope of this study. The EIM benefit analyses that were performed by the Analytical Team are provided in this report.