WorldWideScience

Sample records for architecture reliability analysis

  1. Architecture-Based Reliability Analysis of Web Services

    Science.gov (United States)

    Rahmani, Cobra Mariam

    2012-01-01

    In a Service Oriented Architecture (SOA), the hierarchical complexity of Web Services (WS) and their interactions with the underlying Application Server (AS) create new challenges in providing a realistic estimate of WS performance and reliability. The current approaches often treat the entire WS environment as a black-box. Thus, the sensitivity…

  2. Architecture for interlock systems: reliability analysis with regard to safety and availability

    International Nuclear Information System (INIS)

    Wagner, S.; Apollonio, A.; Schmidt, R.; Zerlauth, M.; Vergara-Fernandez, A.

    2012-01-01

    For particle accelerators like LHC and other large experimental physics facilities like ITER, the machine protection relies on complex interlock systems. In the design of interlock loops for the signal exchange in machine protection systems, the choice of the hardware architecture impacts on machine safety and availability. The reliable performance of a machine stop (leaving the machine in a safe state) in case of an emergency, is an inherent requirement. The constraints in terms of machine availability on the other hand may differ from one facility to another. Spurious machine stops, lowering machine availability, may to a certain extent be tolerated in facilities where they do not cause undue equipment wear-out. In order to compare various interlock loop architectures in terms of safety and availability, the occurrence frequencies of related scenarios have been calculated in a reliability analysis, using a generic analytical model. This paper presents the results and illustrates the potential of the analysis method for supporting the choice of interlock system architectures. The results show the advantages of a 2003 (3 redundant lines with 2-out-of-3 voting) over the 6 architectures under consideration for systems with high requirements in both safety and availability

  3. Analysis of fault tolerance and reliability in distributed real-time system architectures

    International Nuclear Information System (INIS)

    Philippi, Stephan

    2003-01-01

    Safety critical real-time systems are becoming ubiquitous in many areas of our everyday life. Failures of such systems potentially have catastrophic consequences on different scales, in the worst case even the loss of human life. Therefore, safety critical systems have to meet maximum fault tolerance and reliability requirements. As the design of such systems is far from being trivial, this article focuses on concepts to specifically support the early architectural design. In detail, a simulation based approach for the analysis of fault tolerance and reliability in distributed real-time system architectures is presented. With this approach, safety related features can be evaluated in the early development stages and thus prevent costly redesigns in later ones

  4. Reliability analysis of multicellular system architectures for low-cost satellites

    Science.gov (United States)

    Erlank, A. O.; Bridges, C. P.

    2018-06-01

    Multicellular system architectures are proposed as a solution to the problem of low reliability currently seen amongst small, low cost satellites. In a multicellular architecture, a set of independent k-out-of-n systems mimic the cells of a biological organism. In order to be beneficial, a multicellular architecture must provide more reliability per unit of overhead than traditional forms of redundancy. The overheads include power consumption, volume and mass. This paper describes the derivation of an analytical model for predicting a multicellular system's lifetime. The performance of such architectures is compared against that of several common forms of redundancy and proven to be beneficial under certain circumstances. In addition, the problem of peripheral interfaces and cross-strapping is investigated using a purpose-developed, multicellular simulation environment. Finally, two case studies are presented based on a prototype cell implementation, which demonstrate the feasibility of the proposed architecture.

  5. Extending Failure Modes and Effects Analysis Approach for Reliability Analysis at the Software Architecture Design Level

    NARCIS (Netherlands)

    Sözer, Hasan; Tekinerdogan, B.; Aksit, Mehmet; de Lemos, Rogerio; Gacek, Cristina

    2007-01-01

    Several reliability engineering approaches have been proposed to identify and recover from failures. A well-known and mature approach is the Failure Mode and Effect Analysis (FMEA) method that is usually utilized together with Fault Tree Analysis (FTA) to analyze and diagnose the causes of failures.

  6. Design and reliability analysis of DP-3 dynamic positioning control architecture

    Science.gov (United States)

    Wang, Fang; Wan, Lei; Jiang, Da-Peng; Xu, Yu-Ru

    2011-12-01

    As the exploration and exploitation of oil and gas proliferate throughout deepwater area, the requirements on the reliability of dynamic positioning system become increasingly stringent. The control objective ensuring safety operation at deep water will not be met by a single controller for dynamic positioning. In order to increase the availability and reliability of dynamic positioning control system, the triple redundancy hardware and software control architectures were designed and developed according to the safe specifications of DP-3 classification notation for dynamically positioned ships and rigs. The hardware redundant configuration takes the form of triple-redundant hot standby configuration including three identical operator stations and three real-time control computers which connect each other through dual networks. The function of motion control and redundancy management of control computers were implemented by software on the real-time operating system VxWorks. The software realization of task loose synchronization, majority voting and fault detection were presented in details. A hierarchical software architecture was planed during the development of software, consisting of application layer, real-time layer and physical layer. The behavior of the DP-3 dynamic positioning control system was modeled by a Markov model to analyze its reliability. The effects of variation in parameters on the reliability measures were investigated. The time domain dynamic simulation was carried out on a deepwater drilling rig to prove the feasibility of the proposed control architecture.

  7. Architectural design and reliability analysis of a fail-operational brake-by-wire system from ISO 26262 perspectives

    International Nuclear Information System (INIS)

    Sinha, Purnendu

    2011-01-01

    Next generation drive-by-wire automotive systems enabling autonomous driving will build on the fail-operational capabilities of electronics, control and software (ECS) architectural solutions. Developing such architectural designs that would meet dependability requirements and satisfy other system constraints is a challenging task and will possibly lead to a paradigm shift in automotive ECS architecture design and development activities. This aspect is becoming quite relevant while designing battery-driven electric vehicles with integrated in-wheel drive-train and chassis subsystems. In such highly integrated dependable systems, many of the primary features and functions are attributed to the highest safety critical ratings. Brake-by-wire is one such system that interfaces with active safety features built into an automobile, and which in turn is expected to provide fail-operational capabilities. In this paper, building up on the basic concepts of fail-silent and fail-operational systems design we propose a system-architecture for a brake-by-wire system with fail-operational capabilities. The design choices are supported with proper rationale and design trade-offs. Safety and reliability analysis of the proposed system architecture is performed as per the ISO 26262 standard for functional safety of electrical/electronic systems in road vehicles.

  8. A study of digital hardware architectures for nuclear reactors protection systems applications - reliability and safety analysis methods

    International Nuclear Information System (INIS)

    Benko, Pedro Luiz

    1997-01-01

    A study of digital hardware architectures, including experience in many countries, topologies and solutions to interface circuits for protection systems of nuclear reactors is presented. Methods for developing digital systems architectures based on fault tolerant and safety requirements is proposed. Directives for assessing such conditions are suggested. Techniques and the most common tools employed in reliability, safety evaluation and modeling of hardware architectures is also presented. Markov chain modeling is used to evaluate the reliability of redundant architectures. In order to estimate software quality, several mechanisms to be used in design, specification, and validation and verification (V and V) procedures are suggested. A digital protection system architecture has been analyzed as a case study. (author)

  9. Reliability Engineering for Service Oriented Architectures

    Science.gov (United States)

    2013-02-01

    Common Object Request Broker Architecture Ecosystem In software , an ecosystem is a set of applications and/or services that grad- ually build up over time...Enterprise Service Bus Foreign In an SOA context: Any SOA, service or software which the owners of the calling software do not have control of, either...SOA Service Oriented Architecture SRE Software Reliability Engineering System Mode Many systems exhibit different modes of operation. E.g. the cockpit

  10. Sustainable, Reliable Mission-Systems Architecture

    Science.gov (United States)

    O'Neil, Graham; Orr, James K.; Watson, Steve

    2007-01-01

    A mission-systems architecture, based on a highly modular infrastructure utilizing: open-standards hardware and software interfaces as the enabling technology is essential for affordable and sustainable space exploration programs. This mission-systems architecture requires (a) robust communication between heterogeneous system, (b) high reliability, (c) minimal mission-to-mission reconfiguration, (d) affordable development, system integration, and verification of systems, and (e) minimal sustaining engineering. This paper proposes such an architecture. Lessons learned from the Space Shuttle program and Earthbound complex engineered system are applied to define the model. Technology projections reaching out 5 years are mde to refine model details.

  11. ARCHITECTURE AND RELIABILITY OF OPERATING SYSTEMS

    Directory of Open Access Journals (Sweden)

    Stanislav V. Nazarov

    2018-03-01

    Full Text Available Progress in the production technology of microprocessors significantly increased reliability and performance of the computer systems hardware. It cannot be told about the corresponding characteristics of the software and its basis – the operating system (OS. Some achievements of program engineering are more modest in this field. Both directions of OS improvement (increasing of productivity and reliability are connected with the development of effective structures of these systems. OS functional complexity leads to the multiplicity of the structure, which is further enhanced by the specialization of the operating system depending on scope of computer system (complex scientific calculations, real time, information retrieval systems, systems of the automated and automatic control, etc. The functional complexity of the OS leads to the complexity of its architecture, which is further enhanced by the specialization of the operating system, depending on the computer system application area (complex scientific calculations, real-time, information retrieval systems, automated and automatic control systems, etc.. That fact led to variety of modern OS. It is possible to estimate reliability of different OS structures only as results of long-term field experiment or simulation modeling. However it is most often unacceptable because of time and funds expenses for carrying out such research. This survey attempts to evaluate the reliability of two main OS architectures: large multi-layered modular core and a multiserver (client-server system. Represented by continuous Markov chains which are explored in the stationary mode on the basis of transition from systems of the differential equations of Kolmogorov to system of the linear algebraic equations, models of these systems are developed.

  12. The ATLAS Analysis Architecture

    International Nuclear Information System (INIS)

    Cranmer, K.S.

    2008-01-01

    We present an overview of the ATLAS analysis architecture including the relevant aspects of the computing model and the major architectural aspects of the Athena framework. Emphasis will be given to the interplay between the analysis use cases and the technical aspects of the architecture including the design of the event data model, transient-persistent separation, data reduction strategies, analysis tools, and ROOT interoperability

  13. An architectural model for software reliability quantification: sources of data

    International Nuclear Information System (INIS)

    Smidts, C.; Sova, D.

    1999-01-01

    Software reliability assessment models in use today treat software as a monolithic block. An aversion towards 'atomic' models seems to exist. These models appear to add complexity to the modeling, to the data collection and seem intrinsically difficult to generalize. In 1997, we introduced an architecturally based software reliability model called FASRE. The model is based on an architecture derived from the requirements which captures both functional and nonfunctional requirements and on a generic classification of functions, attributes and failure modes. The model focuses on evaluation of failure mode probabilities and uses a Bayesian quantification framework. Failure mode probabilities of functions and attributes are propagated to the system level using fault trees. It can incorporate any type of prior information such as results of developers' testing, historical information on a specific functionality and its attributes, and, is ideally suited for reusable software. By building an architecture and deriving its potential failure modes, the model forces early appraisal and understanding of the weaknesses of the software, allows reliability analysis of the structure of the system, provides assessments at a functional level as well as at a systems' level. In order to quantify the probability of failure (or the probability of success) of a specific element of our architecture, data are needed. The term element of the architecture is used here in its broadest sense to mean a single failure mode or a higher level of abstraction such as a function. The paper surveys the potential sources of software reliability data available during software development. Next the mechanisms for incorporating these sources of relevant data to the FASRE model are identified

  14. Power electronics reliability analysis.

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Mark A.; Atcitty, Stanley

    2009-12-01

    This report provides the DOE and industry with a general process for analyzing power electronics reliability. The analysis can help with understanding the main causes of failures, downtime, and cost and how to reduce them. One approach is to collect field maintenance data and use it directly to calculate reliability metrics related to each cause. Another approach is to model the functional structure of the equipment using a fault tree to derive system reliability from component reliability. Analysis of a fictitious device demonstrates the latter process. Optimization can use the resulting baseline model to decide how to improve reliability and/or lower costs. It is recommended that both electric utilities and equipment manufacturers make provisions to collect and share data in order to lay the groundwork for improving reliability into the future. Reliability analysis helps guide reliability improvements in hardware and software technology including condition monitoring and prognostics and health management.

  15. Human reliability analysis

    International Nuclear Information System (INIS)

    Dougherty, E.M.; Fragola, J.R.

    1988-01-01

    The authors present a treatment of human reliability analysis incorporating an introduction to probabilistic risk assessment for nuclear power generating stations. They treat the subject according to the framework established for general systems theory. Draws upon reliability analysis, psychology, human factors engineering, and statistics, integrating elements of these fields within a systems framework. Provides a history of human reliability analysis, and includes examples of the application of the systems approach

  16. Multidisciplinary System Reliability Analysis

    Science.gov (United States)

    Mahadevan, Sankaran; Han, Song; Chamis, Christos C. (Technical Monitor)

    2001-01-01

    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 Glenn 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 multidisciplinary 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.

  17. Analysis and Application of Reliability

    International Nuclear Information System (INIS)

    Jeong, Hae Seong; Park, Dong Ho; Kim, Jae Ju

    1999-05-01

    This book tells of analysis and application of reliability, which includes definition, importance and historical background of reliability, function of reliability and failure rate, life distribution and assumption of reliability, reliability of unrepaired system, reliability of repairable system, sampling test of reliability, failure analysis like failure analysis by FEMA and FTA, and cases, accelerated life testing such as basic conception, acceleration and acceleration factor, and analysis of accelerated life testing data, maintenance policy about alternation and inspection.

  18. Enterprise Architecture Analysis with XML

    OpenAIRE

    Boer, Frank; Bonsangue, Marcello; Jacob, Joost; Stam, A.; Torre, Leon

    2005-01-01

    htmlabstractThis paper shows how XML can be used for static and dynamic analysis of architectures. Our analysis is based on the distinction between symbolic and semantic models of architectures. The core of a symbolic model consists of its signature that specifies symbolically its structural elements and their relationships. A semantic model is defined as a formal interpretation of the symbolic model. This provides a formal approach to the design of architectural description languages and a g...

  19. Enterprise Architecture Analysis with XML

    NARCIS (Netherlands)

    F.S. de Boer (Frank); M.M. Bonsangue (Marcello); J.F. Jacob (Joost); A. Stam; L.W.N. van der Torre (Leon)

    2005-01-01

    htmlabstractThis paper shows how XML can be used for static and dynamic analysis of architectures. Our analysis is based on the distinction between symbolic and semantic models of architectures. The core of a symbolic model consists of its signature that specifies symbolically its structural

  20. 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

  1. SEARCH FOR A RELIABLE STORAGE ARCHITECTURE FOR RHIC

    International Nuclear Information System (INIS)

    BINELLO, S.; KATZ, R.A.; MORRIS, J.T.

    2007-01-01

    Software used to operate the Relativistic Heavy Ion Collider (RHIC) resides on one operational RAID storage system. This storage system is also used to store data that reflects the status and recent history of accelerator operations. Failure of this system interrupts the operation of the accelerator as backup systems are brought online. In order to increase the reliability of this critical control system component, the storage system architecture has been upgraded to use Storage Area Network (SAN) technology and to introduce redundant components and redundant storage paths. This paper describes the evolution of the storage system, the contributions to reliability that each additional feature has provided, further improvements that are being considered, and real-life experience with the current system

  2. SEARCH FOR A RELIABLE STORAGE ARCHITECTURE FOR RHIC.

    Energy Technology Data Exchange (ETDEWEB)

    BINELLO,S.; KATZ, R.A.; MORRIS, J.T.

    2007-10-15

    Software used to operate the Relativistic Heavy Ion Collider (RHIC) resides on one operational RAID storage system. This storage system is also used to store data that reflects the status and recent history of accelerator operations. Failure of this system interrupts the operation of the accelerator as backup systems are brought online. In order to increase the reliability of this critical control system component, the storage system architecture has been upgraded to use Storage Area Network (SAN) technology and to introduce redundant components and redundant storage paths. This paper describes the evolution of the storage system, the contributions to reliability that each additional feature has provided, further improvements that are being considered, and real-life experience with the current system.

  3. 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.

  4. Software architecture analysis tool : software architecture metrics collection

    NARCIS (Netherlands)

    Muskens, J.; Chaudron, M.R.V.; Westgeest, R.

    2002-01-01

    The Software Engineering discipline lacks the ability to evaluate software architectures. Here we describe a tool for software architecture analysis that is based on metrics. Metrics can be used to detect possible problems and bottlenecks in software architectures. Even though metrics do not give a

  5. 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...

  6. A study of digital hardware architectures for nuclear reactors protection systems applications - reliability and safety analysis methods; Um estudo de arquiteturas de hardware para aplicacao em sistemas digitais de protecao de reatores nucleares - metodos de analise de confiabilidade e seguranca

    Energy Technology Data Exchange (ETDEWEB)

    Benko, Pedro Luiz

    1997-07-01

    A study of digital hardware architectures, including experience in many countries, topologies and solutions to interface circuits for protection systems of nuclear reactors is presented. Methods for developing digital systems architectures based on fault tolerant and safety requirements is proposed. Directives for assessing such conditions are suggested. Techniques and the most common tools employed in reliability, safety evaluation and modeling of hardware architectures is also presented. Markov chain modeling is used to evaluate the reliability of redundant architectures. In order to estimate software quality, several mechanisms to be used in design, specification, and validation and verification (V and V) procedures are suggested. A digital protection system architecture has been analyzed as a case study. (author)

  7. 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

  8. 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)

  9. Scyllac equipment reliability analysis

    International Nuclear Information System (INIS)

    Gutscher, W.D.; Johnson, K.J.

    1975-01-01

    Most of the failures in Scyllac can be related to crowbar trigger cable faults. A new cable has been designed, procured, and is currently undergoing evaluation. When the new cable has been proven, it will be worked into the system as quickly as possible without causing too much additional down time. The cable-tip problem may not be easy or even desirable to solve. A tightly fastened permanent connection that maximizes contact area would be more reliable than the plug-in type of connection in use now, but it would make system changes and repairs much more difficult. The balance of the failures have such a low occurrence rate that they do not cause much down time and no major effort is underway to eliminate them. Even though Scyllac was built as an experimental system and has many thousands of components, its reliability is very good. Because of this the experiment has been able to progress at a reasonable pace

  10. 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

  11. 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

  12. Architectural Analysis of Dynamically Reconfigurable Systems

    Science.gov (United States)

    Lindvall, Mikael; Godfrey, Sally; Ackermann, Chris; Ray, Arnab; Yonkwa, Lyly

    2010-01-01

    oTpics include: the problem (increased flexibility of architectural styles decrease analyzability, behavior emerges and varies depending on the configuration, does the resulting system run according to the intended design, and architectural decisions can impede or facilitate testing); top down approach to architecture analysis, detection of defects and deviations, and architecture and its testability; currently targeted projects GMSEC and CFS; analyzing software architectures; analyzing runtime events; actual architecture recognition; GMPUB in Dynamic SAVE; sample output from new approach; taking message timing delays into account; CFS examples of architecture and testability; some recommendations for improved testablity; and CFS examples of abstract interfaces and testability; CFS example of opening some internal details.

  13. Risk analysis and reliability

    International Nuclear Information System (INIS)

    Uppuluri, V.R.R.

    1979-01-01

    Mathematical foundations of risk analysis are addressed. The importance of having the same probability space in order to compare different experiments is pointed out. Then the following topics are discussed: consequences as random variables with infinite expectations; the phenomenon of rare events; series-parallel systems and different kinds of randomness that could be imposed on such systems; and the problem of consensus of estimates of expert opinion

  14. Network Analysis, Architecture, and Design

    CERN Document Server

    McCabe, James D

    2007-01-01

    Traditionally, networking has had little or no basis in analysis or architectural development, with designers relying on technologies they are most familiar with or being influenced by vendors or consultants. However, the landscape of networking has changed so that network services have now become one of the most important factors to the success of many third generation networks. It has become an important feature of the designer's job to define the problems that exist in his network, choose and analyze several optimization parameters during the analysis process, and then prioritize and evalua

  15. 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

  16. 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...

  17. 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.

  18. 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 ...

  19. 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.

  20. 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)

  1. RSAM: An enhanced architecture for achieving web services reliability in mobile cloud computing

    Directory of Open Access Journals (Sweden)

    Amr S. Abdelfattah

    2018-04-01

    Full Text Available The evolution of the mobile landscape is coupled with the ubiquitous nature of the internet with its intermittent wireless connectivity and the web services. Achieving the web service reliability results in low communication overhead and retrieving the appropriate response. The middleware approach (MA is highly tended to achieve the web service reliability. This paper proposes a Reliable Service Architecture using Middleware (RSAM that achieves the reliable web services consumption. The enhanced architecture focuses on ensuring and tracking the request execution under the communication limitations and service temporal unavailability. It considers the most measurement factors including: request size, response size, and consuming time. We conducted experiments to compare the enhanced architecture with the traditional one. In these experiments, we covered several cases to prove the achievement of reliability. Results also show that the request size was found to be constant, the response size is identical to the traditional architecture, and the increase in the consuming time was less than 5% of the transaction time with the different response sizes. Keywords: Reliable web service, Middleware architecture, Mobile cloud computing

  2. 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.)

  3. Architectural Techniques to Enable Reliable and Scalable Memory Systems

    OpenAIRE

    Nair, Prashant J.

    2017-01-01

    High capacity and scalable memory systems play a vital role in enabling our desktops, smartphones, and pervasive technologies like Internet of Things (IoT). Unfortunately, memory systems are becoming increasingly prone to faults. This is because we rely on technology scaling to improve memory density, and at small feature sizes, memory cells tend to break easily. Today, memory reliability is seen as the key impediment towards using high-density devices, adopting new technologies, and even bui...

  4. Architecture of high reliable control systems using complex software

    International Nuclear Information System (INIS)

    Tallec, M.

    1990-01-01

    The problems involved by the use of complex softwares in control systems that must insure a very high level of safety are examined. The first part makes a brief description of the prototype of PROSPER system. PROSPER means protection system for nuclear reactor with high performances. It has been installed on a French nuclear power plant at the beginnning of 1987 and has been continually working since that time. This prototype is realized on a multi-processors system. The processors communicate between themselves using interruptions and protected shared memories. On each processor, one or more protection algorithms are implemented. Those algorithms use data coming directly from the plant and, eventually, data computed by the other protection algorithms. Each processor makes its own acquisitions from the process and sends warning messages if some operating anomaly is detected. All algorithms are activated concurrently on an asynchronous way. The results are presented and the safety related problems are detailed. - The second part is about measurements' validation. First, we describe how the sensors' measurements will be used in a protection system. Then, a proposal for a method based on the techniques of artificial intelligence (expert systems and neural networks) is presented. - The last part is about the problems of architectures of systems including hardware and software: the different types of redundancies used till now and a proposition of a multi-processors architecture which uses an operating system that is able to manage several tasks implemented on different processors, which verifies the good operating of each of those tasks and of the related processors and which allows to carry on the operation of the system, even in a degraded manner when a failure has been detected are detailed [fr

  5. Lightweight metrics for enterprise architecture analysis

    NARCIS (Netherlands)

    Singh, Prince Mayurank; van Sinderen, Marten J.; Abramowicz, Witold

    2015-01-01

    The role of an Enterprise Architecture model is not limited to a graphical representation of an organization and its dynamics. Rather, it is also a tool for analysis and rational decision making. If firms do not use their enterprise architecture model to aid decision making then they run the risk of

  6. 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

  7. Analysis of Architecture Pattern Usage in Legacy System Architecture Documentation

    NARCIS (Netherlands)

    Harrison, Neil B.; Avgeriou, Paris

    2008-01-01

    Architecture patterns are an important tool in architectural design. However, while many architecture patterns have been identified, there is little in-depth understanding of their actual use in software architectures. For instance, there is no overview of how many patterns are used per system or

  8. 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

  9. 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.

  10. 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

  11. Cost analysis of reliability investigations

    International Nuclear Information System (INIS)

    Schmidt, F.

    1981-01-01

    Taking Epsteins testing theory as a basis, premisses are formulated for the selection of cost-optimized reliability inspection plans. Using an example, the expected testing costs and inspection time periods of various inspection plan types, standardized on the basis of the exponential distribution, are compared. It can be shown that sequential reliability tests usually involve lower costs than failure or time-fixed tests. The most 'costly' test is to be expected with the inspection plan type NOt. (orig.) [de

  12. ARCHITECTURE OF A SENTIMENT ANALYSIS PLATFORM

    Directory of Open Access Journals (Sweden)

    CRISTIAN BUCUR

    2015-06-01

    Full Text Available A new domain of research evolved in the last decade, called sentiment analysis that tries to extract knowledge from opinionated text documents. The article presents an overview of the domain and present an architecture of a system that could perform sentiment analysis processes. Based on previous researches are presented two methods for performing classification and the results obtained.

  13. Reliability Analysis of Money Habitudes

    Science.gov (United States)

    Delgadillo, Lucy M.; Bushman, Brittani S.

    2015-01-01

    Use of the Money Habitudes exercise has gained popularity among various financial professionals. This article reports on the reliability of this resource. A survey administered to young adults at a western state university was conducted, and each Habitude or "domain" was analyzed using Cronbach's alpha procedures. Results showed all six…

  14. 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)

  15. 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.)

  16. 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)

  17. 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...

  18. Within- and between-session reliability of medial gastrocnemius architectural properties

    Directory of Open Access Journals (Sweden)

    JJ McMahon

    2016-05-01

    Full Text Available This study aimed to determine the within- and between-session reliability of medial gastrocnemius (MG architecture (e.g. muscle thickness (MT, fascicle length (FL and pennation angle (PA, as derived via ultrasonography followed by manual digitization. A single rater recorded three ultrasound images of the relaxed MG muscle belly for both legs of 16 resistance trained males, who were positioned in a pronated position with their knees fully extended and the ankles in a neutral (e.g. 90° position. A subset of participants (n = 11 were retested under the same conditions ~48-72 hours after baseline testing. The same rater manually digitized each ultrasound image on three occasions to determine MG MT, FL and PA before pooling the data accordingly to allow for within-image (n = 96, between-image (n = 32 and between-session reliability (n = 22 to be determined. Intraclass correlation coefficients (ICCs demonstrated excellent within-image (ICCs = 0.99-1.00, P < 0.001 and very good between-image (ICCs = 0.83-0.95, P < 0.001 and between-session (ICCs = 0.89- 0.95, P < 0.001 reliability for MT, FL and PA. Between-session coefficient of variation was low (≤ 3.6% for each architectural parameter and smallest detectible difference values of 10.6%, 11.4% and 9.8% were attained for MT, FL and PA, respectively. Manually digitizing ultrasound images of the MG muscle at rest yields highly reliable measurements of its architectural properties. Furthermore, changes in MG MT, FL and PA of ≥ 10.6%, 11.4% and 9.8% respectively, as brought about by any form of intervention, should be considered meaningful.

  19. 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.

  20. 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.

  1. Reliability analysis using network simulation

    International Nuclear Information System (INIS)

    Engi, D.

    1985-01-01

    The models that can be used to provide estimates of the reliability of nuclear power systems operate at many different levels of sophistication. The least-sophisticated models treat failure processes that entail only time-independent phenomena (such as demand failure). More advanced models treat processes that also include time-dependent phenomena such as run failure and possibly repair. However, many of these dynamic models are deficient in some respects because they either disregard the time-dependent phenomena that cannot be expressed in closed-form analytic terms or because they treat these phenomena in quasi-static terms. The next level of modeling requires a dynamic approach that incorporates not only procedures for treating all significant time-dependent phenomena but also procedures for treating these phenomena when they are conditionally linked or characterized by arbitrarily selected probability distributions. The level of sophistication that is required is provided by a dynamic, Monte Carlo modeling approach. A computer code that uses a dynamic, Monte Carlo modeling approach is Q-GERT (Graphical Evaluation and Review Technique - with Queueing), and the present study had demonstrated the feasibility of using Q-GERT for modeling time-dependent, unconditionally and conditionally linked phenomena that are characterized by arbitrarily selected probability distributions

  2. Analysis of information security reliability: A tutorial

    International Nuclear Information System (INIS)

    Kondakci, Suleyman

    2015-01-01

    This article presents a concise reliability analysis of network security abstracted from stochastic modeling, reliability, and queuing theories. Network security analysis is composed of threats, their impacts, and recovery of the failed systems. A unique framework with a collection of the key reliability models is presented here to guide the determination of the system reliability based on the strength of malicious acts and performance of the recovery processes. A unique model, called Attack-obstacle model, is also proposed here for analyzing systems with immunity growth features. Most computer science curricula do not contain courses in reliability modeling applicable to different areas of computer engineering. Hence, the topic of reliability analysis is often too diffuse to most computer engineers and researchers dealing with network security. This work is thus aimed at shedding some light on this issue, which can be useful in identifying models, their assumptions and practical parameters for estimating the reliability of threatened systems and for assessing the performance of recovery facilities. It can also be useful for the classification of processes and states regarding the reliability of information systems. Systems with stochastic behaviors undergoing queue operations and random state transitions can also benefit from the approaches presented here. - Highlights: • A concise survey and tutorial in model-based reliability analysis applicable to information security. • A framework of key modeling approaches for assessing reliability of networked systems. • The framework facilitates quantitative risk assessment tasks guided by stochastic modeling and queuing theory. • Evaluation of approaches and models for modeling threats, failures, impacts, and recovery analysis of information systems

  3. Reliability of biceps femoris and semitendinosus muscle architecture measurements obtained with ultrasonography

    Directory of Open Access Journals (Sweden)

    Viviane Bastos de Oliveira

    Full Text Available Introduction Currently, little attention is given to the muscle architecture reliability studies of the hamstring using a robust statistical. Our purpose was to determine the reliability of ultrasound measurements of muscle thickness, fascicle length and pennation angle of the biceps femoris and semitendinosus muscles, including heteroskedasticity and internal consistency analyses. Methods Two images of biceps femoris and semitendinosus at 50% of the thigh length were acquired from 21 volunteers, in two visits. The parameters were measured three times in each image, and for each muscle. The reliability was analyzed by the intraclass correlation coefficient (ICC and Cronbach’s alpha (αCronbach. The relative standard error of the measurements (%SEM were calculated and Bland-Altman plots were generated. Results All parameters presented excellent ICC for the three repeated measurements (ICC from 0.93 ‒ 0.99 and moderate to excellent reliability intraday (ICC from 0.70 ‒ 0.95 for both muscles. The present study indicates that ultrasound is a reliable tool to estimate the biceps femoris fascicle length (ICC = 0.97, αCronbach = 0.98, %SEM = 7.86 and semitendinosus (ICC = 0.90, αCronbach = 0.95, %SEM = 7.55, as well as the biceps femoris muscle thickness (ICC = 0.89, αCronbach = 0.94, %SEM = 10.23 and semitendinosus muscle thickness (ICC = 0.87, αCronbach = 0.93, %SEM = 1.35. At last, biceps femoris pennation angle (ICC = 0.93, αCronbach = 0.96 and %SEM = 4.36 and semitendinosus (ICC = 0.96, αCronbach = 0.98 and %SEM = 4.25 also had good repeatability. Conclusion Ultrasonography show good repeatability in estimating of muscle architecture parameters.

  4. 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...

  5. 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

  6. 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.

  7. 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.

  8. Using Multimedia for Teaching Analysis in History of Modern Architecture.

    Science.gov (United States)

    Perryman, Garry

    This paper presents a case for the development and support of a computer-based interactive multimedia program for teaching analysis in community college architecture design programs. Analysis in architecture design is an extremely important strategy for the teaching of higher-order thinking skills, which senior schools of architecture look for in…

  9. 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)

  10. 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

  11. UMA/GAN network architecture analysis

    Science.gov (United States)

    Yang, Liang; Li, Wensheng; Deng, Chunjian; Lv, Yi

    2009-07-01

    This paper is to critically analyze the architecture of UMA which is one of Fix Mobile Convergence (FMC) solutions, and also included by the third generation partnership project(3GPP). In UMA/GAN network architecture, UMA Network Controller (UNC) is the key equipment which connects with cellular core network and mobile station (MS). UMA network could be easily integrated into the existing cellular networks without influencing mobile core network, and could provides high-quality mobile services with preferentially priced indoor voice and data usage. This helps to improve subscriber's experience. On the other hand, UMA/GAN architecture helps to integrate other radio technique into cellular network which includes WiFi, Bluetooth, and WiMax and so on. This offers the traditional mobile operators an opportunity to integrate WiMax technique into cellular network. In the end of this article, we also give an analysis of potential influence on the cellular core networks ,which is pulled by UMA network.

  12. 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

  13. 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)

  14. Reliability Evaluation of Service-Oriented Architecture Systems Considering Fault-Tolerance Designs

    Directory of Open Access Journals (Sweden)

    Kuan-Li Peng

    2014-01-01

    strategies. Sensitivity analysis of SOA at both coarse and fine grain levels is also studied, which can be used to efficiently identify the critical parts within the system. Two SOA system scenarios based on real industrial practices are studied. Experimental results show that the proposed SOA model can be used to accurately depict the behavior of SOA systems. Additionally, a sensitivity analysis that quantizes the effects of system structure as well as fault tolerance on the overall reliability is also studied. On the whole, the proposed reliability modeling and analysis framework may help the SOA system service provider to evaluate the overall system reliability effectively and also make smarter improvement plans by focusing resources on enhancing reliability-sensitive parts within the system.

  15. Understanding Extraordinary Architectural Experiences through Content Analysis of Written Narratives

    Directory of Open Access Journals (Sweden)

    Brandon Richard Ro

    2015-12-01

    Full Text Available This study a identifies how people describe, characterize, and communicate in written form Extraordinary Architectural Experiences (EAE, and b expands the traditional qualitative approach to architectural phenomenology by demonstrating a quantitative method to analyze written narratives. Specifically, this study reports on the content analysis of 718 personal accounts of EAEs. Using a deductive, ‘theory-driven’ approach, these narratives were read, coded, and statistically analyzed to identify storyline structure, convincing power, and the relationship between subjective and objective experiential qualities used in the story-telling process. Statistical intercoder agreement tests were conducted to verify the reliability of the interpretations to approach the hard problem of “extraordinary aesthetics” in architecture empirically. The results of this study confirm the aesthetic nature of EAE narratives (and of told experiences by showing their higher dependence on external objective content (e.g., a building’s features and location rather than its internal subjective counterpart (e.g., emotions and sensations, which makes them more outwardly focused. The strong interrelationships and intercoder agreement between the thematic realms provide a unique aesthetic construct revealing EAE narratives as memorable, embodied, emotional events mapped by the externally focused content of place, social setting, time, and building features. A majority of EAE narratives were found to possess plot-structure along with significant relationships to objective-subjective content that further grounded their storylines. This study concludes that content analysis provides not only a valid method to understand written narratives about extraordinary architectural experiences quantitatively, but also a view as to how to map the unique nature of aesthetic phenomenology empirically.

  16. Analysis of the new architecture proposal for the CMM control system

    International Nuclear Information System (INIS)

    Heikkilae, L.; Saarinen, H.; Aha, L.; Viinikainen, M.; Mattila, J.; Hahto, A.; Siuko, M.; Semeraro, L.

    2011-01-01

    While developing divertor remote handling maintenance systems at the Divertor Test Platform 2 facility, some risks and sensitivity points related to the Cassette Multifunctional Mover control system software were discovered and evaluated. The control system architecture has to simultaneously fulfill the demanding ITER remote handling requirements and to face new requirements being uncovered during the trials. Especially evolving non-functional requirements such as reliability and safety have an effect on the control system architecture as it is getting more mature. An evaluation of the implications from architectural decisions is necessary before implementation efforts, as an architecture left to develop without evaluation may lead to a dead end and therefore soaring development costs. After studying existing architecture analysis methods an analysis method was developed to gain confidence to carry out the proposed changes.

  17. 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...

  18. 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

  19. 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.

  20. Steam generator thermal hydraulic design & functional architecture features and related operational and reliability issues requiring consideration

    International Nuclear Information System (INIS)

    Klarner, R.G.

    2012-01-01

    Proper thermal hydraulic design and functional architecture are critical to successful steam generator operation and long term reliability. The evolution of steam generators has been a gradual learning process that has benefited from continuous industry operational experience (OPEX). Inadequate thermal hydraulic design can lead to numerous degradation mechanisms such as excessive deposition, corrosion, flow and level instabilities, fluid-elastic instabilities and tube wear. The functional architecture determines the health of the tube bundle and the other internals during manufacturing, handling and operation. It also determines thermal performance as well as establishing global thermal-hydraulic characteristics such as water level shrink and swell response. This paper discusses the range of operational and reliability issues and relates them to the thermal hydraulic attributes and functional architecture of steam generators (many SG reliability issues are further discussed in other presentations at this conference). In pursuing such issues, the paper focuses on the four major features of the equipment, identifying in each case the goals and requirements such features must meet. Typical approaches and the means by which such requirements are addressed in current equipment are discussed. The four features are: 1. Tubing Material and Tube Bundle Heat Transfer Performance; a. Two materials are in current use – Alloy 690 TT and Alloy 800. Both are good materials with excellent performance records which serve their owners very well (the reliability attributes of Alloy 800 and 690 are discussed in other papers at this conference). Caution is advised in the supply of any material: – material quality is only assured by what is specified to material suppliers in procurement specifications – i.e. - all the knowledge and research in the world assures nothing if its findings are not reflected in procurement requirements. b. Heat transfer performance in addition to being

  1. 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.

  2. 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...

  3. The architecture of a reliable software monitoring system for embedded software systems

    International Nuclear Information System (INIS)

    Munson, J.; Krings, A.; Hiromoto, R.

    2006-01-01

    away from the currently applied paradigm of addressing reliability, security and survivability in an add-on fashion at the end of the software development process. Rather, the integrity monitoring ability will be integrated into the overall architecture of the software system. The measurement and control methodology developed under this research program will readily migrate into hardware, leading to the development of new hardware architecture with built-in survivability, security and reliability attributes. (authors)

  4. 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)

  5. A Sustainable, Reliable Mission-Systems Architecture that Supports a System of Systems Approach to Space Exploration

    Science.gov (United States)

    Watson, Steve; Orr, Jim; O'Neil, Graham

    2004-01-01

    A mission-systems architecture based on a highly modular "systems of systems" infrastructure utilizing open-standards hardware and software interfaces as the enabling technology is absolutely essential for an affordable and sustainable space exploration program. This architecture requires (a) robust communication between heterogeneous systems, (b) high reliability, (c) minimal mission-to-mission reconfiguration, (d) affordable development, system integration, and verification of systems, and (e) minimum sustaining engineering. This paper proposes such an architecture. Lessons learned from the space shuttle program are applied to help define and refine the model.

  6. 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.

  7. 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

  8. 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)

  9. 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)

  10. 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.)

  11. 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

  12. 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.

  13. Architecture

    OpenAIRE

    Clear, Nic

    2014-01-01

    When discussing science fiction’s relationship with architecture, the usual practice is to look at the architecture “in” science fiction—in particular, the architecture in SF films (see Kuhn 75-143) since the spaces of literary SF present obvious difficulties as they have to be imagined. In this essay, that relationship will be reversed: I will instead discuss science fiction “in” architecture, mapping out a number of architectural movements and projects that can be viewed explicitly as scien...

  14. 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

  15. 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

  16. 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.

  17. 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.

  18. 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.

  19. Advanced Concept Architecture Design and Integrated Analysis (ACADIA)

    Science.gov (United States)

    2017-11-03

    1 Advanced Concept Architecture Design and Integrated Analysis (ACADIA) Submitted to the National Institute of Aerospace (NIA) on...Research Report 20161001 - 20161030 Advanced Concept Architecture Design and Integrated Analysis (ACADIA) W911NF-16-2-0229 8504Cedric Justin, Youngjun

  20. Fractal analysis of bone architecture at distal radius

    International Nuclear Information System (INIS)

    Tomomitsu, Tatsushi; Mimura, Hiroaki; Murase, Kenya; Sone, Teruki; Fukunaga, Masao

    2005-01-01

    Bone strength depends on bone quality (architecture, turnover, damage accumulation, and mineralization) as well as bone mass. In this study, human bone architecture was analyzed using fractal image analysis, and the clinical relevance of this method was evaluated. The subjects were 12 healthy female controls and 16 female patients suspected of having osteoporosis (age range, 22-70 years; mean age, 49.1 years). High-resolution CT images of the distal radius were acquired and analyzed using a peripheral quantitative computed tomography (pQCT) system. On the same day, bone mineral densities of the lumbar spine (L-BMD), proximal femur (F-BMD), and distal radius (R-BMD) were measured by dual-energy X-ray absorptiometry (DXA). We examined the correlation between the fractal dimension and six bone mass indices. Subjects diagnosed with osteopenia or osteoporosis were divided into two groups (with and without vertebral fracture), and we compared measured values between these two groups. The fractal dimension correlated most closely with L-BMD (r=0.744). The coefficient of correlation between the fractal dimension and L-BMD was very similar to the coefficient of correlation between L-BMD and F-BMD (r=0.783) and the coefficient of correlation between L-BMD and R-BMD (r=0.742). The fractal dimension was the only measured value that differed significantly between both the osteopenic and the osteoporotic subjects with and without vertebral fracture. The present results suggest that the fractal dimension of the distal radius can be reliably used as a bone strength index that reflects bone architecture as well as bone mass. (author)

  1. 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

  2. Information architecture. Volume 2, Part 1: Baseline analysis summary

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-12-01

    The Department of Energy (DOE) Information Architecture, Volume 2, Baseline Analysis, is a collaborative and logical next-step effort in the processes required to produce a Departmentwide information architecture. The baseline analysis serves a diverse audience of program management and technical personnel and provides an organized way to examine the Department`s existing or de facto information architecture. A companion document to Volume 1, The Foundations, it furnishes the rationale for establishing a Departmentwide information architecture. This volume, consisting of the Baseline Analysis Summary (part 1), Baseline Analysis (part 2), and Reference Data (part 3), is of interest to readers who wish to understand how the Department`s current information architecture technologies are employed. The analysis identifies how and where current technologies support business areas, programs, sites, and corporate systems.

  3. Reliability Analysis Multiple Redundancy Controller for Nuclear Safety Systems

    International Nuclear Information System (INIS)

    Son, Gwangseop; Kim, Donghoon; Son, Choulwoong

    2013-01-01

    This controller is configured for multiple modular redundancy (MMR) composed of dual modular redundancy (DMR) and triple modular redundancy (TMR). The architecture of MRC is briefly described, and the Markov model is developed. Based on the model, the reliability and Mean Time To Failure (MTTF) are analyzed. In this paper, the architecture of MRC for nuclear safety systems is described. The MRC is configured for multiple modular redundancy (MMR) composed of dual modular redundancy (DMR) and triple modular redundancy (TMR). Markov models for MRC architecture was developed, and then the reliability was analyzed by using the model. From the reliability analyses for the MRC, it is obtained that the failure rate of each module in the MRC should be less than 2 Χ 10 -4 /hour and the MTTF average increase rate depending on FCF increment, i. e. ΔMTTF/ΔFCF, is 4 months/0.1

  4. Architectural design and analysis of a programmable image processor

    International Nuclear Information System (INIS)

    Siyal, M.Y.; Chowdhry, B.S.; Rajput, A.Q.K.

    2003-01-01

    In this paper we present an architectural design and analysis of a programmable image processor, nicknamed Snake. The processor was designed with a high degree of parallelism to speed up a range of image processing operations. Data parallelism found in array processors has been included into the architecture of the proposed processor. The implementation of commonly used image processing algorithms and their performance evaluation are also discussed. The performance of Snake is also compared with other types of processor architectures. (author)

  5. A taxonomy for human reliability analysis

    International Nuclear Information System (INIS)

    Beattie, J.D.; Iwasa-Madge, K.M.

    1984-01-01

    A human interaction taxonomy (classification scheme) was developed to facilitate human reliability analysis in a probabilistic safety evaluation of a nuclear power plant, being performed at Ontario Hydro. A human interaction occurs, by definition, when operators or maintainers manipulate, or respond to indication from, a plant component or system. The taxonomy aids the fault tree analyst by acting as a heuristic device. It helps define the range and type of human errors to be identified in the construction of fault trees, while keeping the identification by different analysts consistent. It decreases the workload associated with preliminary quantification of the large number of identified interactions by including a category called 'simple interactions'. Fault tree analysts quantify these according to a procedure developed by a team of human reliability specialists. The interactions which do not fit into this category are called 'complex' and are quantified by the human reliability team. The taxonomy is currently being used in fault tree construction in a probabilistic safety evaluation. As far as can be determined at this early stage, the potential benefits of consistency and completeness in identifying human interactions and streamlining the initial quantification are being realized

  6. Reliable and Efficient Parallel Processing Algorithms and Architectures for Modern Signal Processing. Ph.D. Thesis

    Science.gov (United States)

    Liu, Kuojuey Ray

    1990-01-01

    Least-squares (LS) estimations and spectral decomposition algorithms constitute the heart of modern signal processing and communication problems. Implementations of recursive LS and spectral decomposition algorithms onto parallel processing architectures such as systolic arrays with efficient fault-tolerant schemes are the major concerns of this dissertation. There are four major results in this dissertation. First, we propose the systolic block Householder transformation with application to the recursive least-squares minimization. It is successfully implemented on a systolic array with a two-level pipelined implementation at the vector level as well as at the word level. Second, a real-time algorithm-based concurrent error detection scheme based on the residual method is proposed for the QRD RLS systolic array. The fault diagnosis, order degraded reconfiguration, and performance analysis are also considered. Third, the dynamic range, stability, error detection capability under finite-precision implementation, order degraded performance, and residual estimation under faulty situations for the QRD RLS systolic array are studied in details. Finally, we propose the use of multi-phase systolic algorithms for spectral decomposition based on the QR algorithm. Two systolic architectures, one based on triangular array and another based on rectangular array, are presented for the multiphase operations with fault-tolerant considerations. Eigenvectors and singular vectors can be easily obtained by using the multi-pase operations. Performance issues are also considered.

  7. 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

  8. 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

  9. 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

  10. Change Impact Analysis of Crosscutting in Software Architectural Design

    NARCIS (Netherlands)

    van den Berg, Klaas

    2006-01-01

    Software architectures should be amenable to changes in user requirements and implementation technology. The analysis of the impact of these changes can be based on traceability of architectural design elements. Design elements have dependencies with other software artifacts but also evolve in time.

  11. Advancing Usability Evaluation through Human Reliability Analysis

    International Nuclear Information System (INIS)

    Ronald L. Boring; David I. Gertman

    2005-01-01

    This paper introduces a novel augmentation to the current heuristic usability evaluation methodology. The SPAR-H human reliability analysis method was developed for categorizing human performance in nuclear power plants. Despite the specialized use of SPAR-H for safety critical scenarios, the method also holds promise for use in commercial off-the-shelf software usability evaluations. The SPAR-H method shares task analysis underpinnings with human-computer interaction, and it can be easily adapted to incorporate usability heuristics as performance shaping factors. By assigning probabilistic modifiers to heuristics, it is possible to arrive at the usability error probability (UEP). This UEP is not a literal probability of error but nonetheless provides a quantitative basis to heuristic evaluation. When combined with a consequence matrix for usability errors, this method affords ready prioritization of usability issues

  12. Integrated Reliability and Risk Analysis System (IRRAS)

    International Nuclear Information System (INIS)

    Russell, K.D.; McKay, M.K.; Sattison, M.B.; Skinner, N.L.; Wood, S.T.; Rasmuson, D.M.

    1992-01-01

    The Integrated Reliability and Risk Analysis System (IRRAS) is a state-of-the-art, microcomputer-based probabilistic risk assessment (PRA) model development and analysis tool to address key nuclear plant safety issues. IRRAS is an integrated software tool that gives the user the ability to create and analyze fault trees and accident sequences using a microcomputer. This program provides functions that range from graphical fault tree construction to cut set generation and quantification. Version 1.0 of the IRRAS program was released in February of 1987. Since that time, many user comments and enhancements have been incorporated into the program providing a much more powerful and user-friendly system. This version has been designated IRRAS 4.0 and is the subject of this Reference Manual. Version 4.0 of IRRAS provides the same capabilities as Version 1.0 and adds a relational data base facility for managing the data, improved functionality, and improved algorithm performance

  13. 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)

  14. 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

  15. 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

  16. 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.

  17. 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)

  18. 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....

  19. Human Reliability Analysis For Computerized Procedures

    International Nuclear Information System (INIS)

    Boring, Ronald L.; Gertman, David I.; Le Blanc, Katya

    2011-01-01

    This paper provides a characterization of human reliability analysis (HRA) issues for computerized procedures in nuclear power plant control rooms. It is beyond the scope of this paper to propose a new HRA approach or to recommend specific methods or refinements to those methods. Rather, this paper provides a review of HRA as applied to traditional paper-based procedures, followed by a discussion of what specific factors should additionally be considered in HRAs for computerized procedures. Performance shaping factors and failure modes unique to computerized procedures are highlighted. Since there is no definitive guide to HRA for paper-based procedures, this paper also serves to clarify the existing guidance on paper-based procedures before delving into the unique aspects of computerized procedures.

  20. Reliability Analysis of Structural Timber Systems

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Hoffmeyer, P.

    2000-01-01

    Structural systems like timber trussed rafters and roof elements made of timber can be expected to have some degree of redundancy and nonlinear/plastic behaviour when the loading consists of for example snow or imposed load. In this paper this system effect is modelled and the statistic...... of variation. In the paper a stochastic model is described for the strength of a single piece of timber taking into account the stochastic variation of the strength and stiffness with length. Also stochastic models for different types of loads are formulated. First, simple representative systems with different...... types of redundancy and non-linearity are considered. The statistical characteristics of the load bearing capacity are determined by reliability analysis. Next, more complex systems are considered modelling the mechanical behaviour of timber roof elements I stressed skin panels made of timber. Using...

  1. Human reliability analysis of dependent events

    International Nuclear Information System (INIS)

    Swain, A.D.; Guttmann, H.E.

    1977-01-01

    In the human reliability analysis in WASH-1400, the continuous variable of degree of interaction among human events was approximated by selecting four points on this continuum to represent the entire continuum. The four points selected were identified as zero coupling (i.e., zero dependence), complete coupling (i.e., complete dependence), and two intermediate points--loose coupling (a moderate level of dependence) and tight coupling (a high level of dependence). The paper expands the WASH-1400 treatment of common mode failure due to the interaction of human activities. Mathematical expressions for the above four levels of dependence are derived for parallel and series systems. The psychological meaning of each level of dependence is illustrated by examples, with probability tree diagrams to illustrate the use of conditional probabilities resulting from the interaction of human actions in nuclear power plant tasks

  2. Reliability analysis of steel-containment strength

    International Nuclear Information System (INIS)

    Greimann, L.G.; Fanous, F.; Wold-Tinsae, A.; Ketalaar, D.; Lin, T.; Bluhm, D.

    1982-06-01

    A best estimate and uncertainty assessment of the resistance of the St. Lucie, Cherokee, Perry, WPPSS and Browns Ferry containment vessels was performed. The Monte Carlo simulation technique and second moment approach were compared as a means of calculating the probability distribution of the containment resistance. A uniform static internal pressure was used and strain ductility was taken as the failure criterion. Approximate methods were developed and calibrated with finite element analysis. Both approximate and finite element analyses were performed on the axisymmetric containment structure. An uncertainty assessment of the containment strength was then performed by the second moment reliability method. Based upon the approximate methods, the cumulative distribution for the resistance of each of the five containments (shell modes only) is presented

  3. Standardizing the practice of human reliability analysis

    International Nuclear Information System (INIS)

    Hallbert, B.P.

    1993-01-01

    The practice of human reliability analysis (HRA) within the nuclear industry varies greatly in terms of posited mechanisms that shape human performance, methods of characterizing and analytically modeling human behavior, and the techniques that are employed to estimate the frequency with which human error occurs. This variation has been a source of contention among HRA practitioners regarding the validity of results obtained from different HRA methods. It has also resulted in attempts to develop standard methods and procedures for conducting HRAs. For many of the same reasons, the practice of HRA has not been standardized or has been standardized only to the extent that individual analysts have developed heuristics and consistent approaches in their practice of HRA. From the standpoint of consumers and regulators, this has resulted in a lack of clear acceptance criteria for the assumptions, modeling, and quantification of human errors in probabilistic risk assessments

  4. Architectural analysis of Douglas-fir forests

    NARCIS (Netherlands)

    Kuiper, L.C.

    1994-01-01

    The architecture of natural and semi-natural Douglas-fir forest ecosystems in western Washington and western Oregon was analyzed by various case-studies, to yield vital information needed for the design of new silvicultural systems with a high level of biodiversity, intended for low-input

  5. Human Reliability Analysis for Small Modular Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Ronald L. Boring; David I. Gertman

    2012-06-01

    Because no human reliability analysis (HRA) method was specifically developed for small modular reactors (SMRs), the application of any current HRA method to SMRs represents tradeoffs. A first- generation HRA method like THERP provides clearly defined activity types, but these activity types do not map to the human-system interface or concept of operations confronting SMR operators. A second- generation HRA method like ATHEANA is flexible enough to be used for SMR applications, but there is currently insufficient guidance for the analyst, requiring considerably more first-of-a-kind analyses and extensive SMR expertise in order to complete a quality HRA. Although no current HRA method is optimized to SMRs, it is possible to use existing HRA methods to identify errors, incorporate them as human failure events in the probabilistic risk assessment (PRA), and quantify them. In this paper, we provided preliminary guidance to assist the human reliability analyst and reviewer in understanding how to apply current HRA methods to the domain of SMRs. While it is possible to perform a satisfactory HRA using existing HRA methods, ultimately it is desirable to formally incorporate SMR considerations into the methods. This may require the development of new HRA methods. More practicably, existing methods need to be adapted to incorporate SMRs. Such adaptations may take the form of guidance on the complex mapping between conventional light water reactors and small modular reactors. While many behaviors and activities are shared between current plants and SMRs, the methods must adapt if they are to perform a valid and accurate analysis of plant personnel performance in SMRs.

  6. Joint C4ISR Architecture Planning/Analysis System (JCAPS)

    National Research Council Canada - National Science Library

    Wostbrock, Bill

    2002-01-01

    The contractor satisfactorily completed all tasks under both efforts, providing the technology and technical expertise in the development of the Joint C4ISR Architecture Planning/Analysis System (JCAPS) Database Tool...

  7. Task Decomposition in Human Reliability Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Boring, Ronald Laurids [Idaho National Laboratory; Joe, Jeffrey Clark [Idaho National Laboratory

    2014-06-01

    In the probabilistic safety assessments (PSAs) used in the nuclear industry, human failure events (HFEs) are determined as a subset of hardware failures, namely those hardware failures that could be triggered by human action or inaction. This approach is top-down, starting with hardware faults and deducing human contributions to those faults. Elsewhere, more traditionally human factors driven approaches would tend to look at opportunities for human errors first in a task analysis and then identify which of those errors is risk significant. The intersection of top-down and bottom-up approaches to defining HFEs has not been carefully studied. Ideally, both approaches should arrive at the same set of HFEs. This question remains central as human reliability analysis (HRA) methods are generalized to new domains like oil and gas. The HFEs used in nuclear PSAs tend to be top-down— defined as a subset of the PSA—whereas the HFEs used in petroleum quantitative risk assessments (QRAs) are more likely to be bottom-up—derived from a task analysis conducted by human factors experts. The marriage of these approaches is necessary in order to ensure that HRA methods developed for top-down HFEs are also sufficient for bottom-up applications.

  8. The analysis of cultural architectural trends in Crisan locality

    Directory of Open Access Journals (Sweden)

    SELA Florentina

    2010-09-01

    Full Text Available The paper presents data about the identification and analyse of the traditional architectural elements in Crisan locality knowing that the tourism activity is in a continuous development. The field research (during November 2007 enabled us to develop a qualitative and quantitative analysis in terms of identification of traditional architecture elements, their conservation status, and frequency of traditional building materials use, decorative elements and specificcolors used in construction architecture. Further, based on collected data, was realized the chart - Distribution for TraditionalArchitecture Index (TAI on the distance from the center of Crisan locality, showing that in Crisan locality the houses were and are built without taking into account any rule, destroying thus traditional architecture.

  9. Analysis of MANET Security, Architecture and Assessment

    OpenAIRE

    Sweta Kaushik; Manorma Kaushik

    2012-01-01

    in these days, the Mobile ad hoc network (MANET) technology spreads widely. Architecture and security issue is the most sensitive challenge of MANET. MANET support to nodes for directly communications with all the other nodes within their radio ranges through multiple wireless links, where the nodes are not in the direct communication range using intermediate node(s) to communicate with each other. In a MANET, the users’ mobile devices behave as a network, and they must cooperatively provide ...

  10. Finite element reliability analysis of fatigue life

    International Nuclear Information System (INIS)

    Harkness, H.H.; Belytschko, T.; Liu, W.K.

    1992-01-01

    Fatigue reliability is addressed by the first-order reliability method combined with a finite element method. Two-dimensional finite element models of components with cracks in mode I are considered with crack growth treated by the Paris law. Probability density functions of the variables affecting fatigue are proposed to reflect a setting where nondestructive evaluation is used, and the Rosenblatt transformation is employed to treat non-Gaussian random variables. Comparisons of the first-order reliability results and Monte Carlo simulations suggest that the accuracy of the first-order reliability method is quite good in this setting. Results show that the upper portion of the initial crack length probability density function is crucial to reliability, which suggests that if nondestructive evaluation is used, the probability of detection curve plays a key role in reliability. (orig.)

  11. Modeling human reliability analysis using MIDAS

    International Nuclear Information System (INIS)

    Boring, R. L.

    2006-01-01

    This paper documents current efforts to infuse human reliability analysis (HRA) into human performance simulation. The Idaho National Laboratory is teamed with NASA Ames Research Center to bridge the SPAR-H HRA method with NASA's Man-machine Integration Design and Analysis System (MIDAS) for use in simulating and modeling the human contribution to risk in nuclear power plant control room operations. It is anticipated that the union of MIDAS and SPAR-H will pave the path for cost-effective, timely, and valid simulated control room operators for studying current and next generation control room configurations. This paper highlights considerations for creating the dynamic HRA framework necessary for simulation, including event dependency and granularity. This paper also highlights how the SPAR-H performance shaping factors can be modeled in MIDAS across static, dynamic, and initiator conditions common to control room scenarios. This paper concludes with a discussion of the relationship of the workload factors currently in MIDAS and the performance shaping factors in SPAR-H. (authors)

  12. 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...

  13. 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

  14. Fiber Access Networks: Reliability Analysis and Swedish Broadband Market

    Science.gov (United States)

    Wosinska, Lena; Chen, Jiajia; Larsen, Claus Popp

    Fiber access network architectures such as active optical networks (AONs) and passive optical networks (PONs) have been developed to support the growing bandwidth demand. Whereas particularly Swedish operators prefer AON, this may not be the case for operators in other countries. The choice depends on a combination of technical requirements, practical constraints, business models, and cost. Due to the increasing importance of reliable access to the network services, connection availability is becoming one of the most crucial issues for access networks, which should be reflected in the network owner's architecture decision. In many cases protection against failures is realized by adding backup resources. However, there is a trade off between the cost of protection and the level of service reliability since improving reliability performance by duplication of network resources (and capital expenditures CAPEX) may be too expensive. In this paper we present the evolution of fiber access networks and compare reliability performance in relation to investment and management cost for some representative cases. We consider both standard and novel architectures for deployment in both sparsely and densely populated areas. While some recent works focused on PON protection schemes with reduced CAPEX the current and future effort should be put on minimizing the operational expenditures (OPEX) during the access network lifetime.

  15. Security Analysis of Dynamic SDN Architectures Based on Game Theory

    Directory of Open Access Journals (Sweden)

    Chao Qi

    2018-01-01

    Full Text Available Security evaluation of SDN architectures is of critical importance to develop robust systems and address attacks. Focused on a novel-proposed dynamic SDN framework, a game-theoretic model is presented to analyze its security performance. This model can represent several kinds of players’ information, simulate approximate attack scenarios, and quantitatively estimate systems’ reliability. And we explore several typical game instances defined by system’s capability, players’ objects, and strategies. Experimental results illustrate that the system’s detection capability is not a decisive element to security enhancement as introduction of dynamism and redundancy into SDN can significantly improve security gain and compensate for its detection weakness. Moreover, we observe a range of common strategic actions across environmental conditions. And analysis reveals diverse defense mechanisms adopted in dynamic systems have different effect on security improvement. Besides, the existence of equilibrium in particular situations further proves the novel structure’s feasibility, flexibility, and its persistent ability against long-term attacks.

  16. 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

  17. 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

  18. Space Mission Human Reliability Analysis (HRA) Project

    Science.gov (United States)

    Boyer, Roger

    2014-01-01

    The purpose of the Space Mission Human Reliability Analysis (HRA) Project is to extend current ground-based HRA risk prediction techniques to a long-duration, space-based tool. Ground-based HRA methodology has been shown to be a reasonable tool for short-duration space missions, such as Space Shuttle and lunar fly-bys. However, longer-duration deep-space missions, such as asteroid and Mars missions, will require the crew to be in space for as long as 400 to 900 day missions with periods of extended autonomy and self-sufficiency. Current indications show higher risk due to fatigue, physiological effects due to extended low gravity environments, and others, may impact HRA predictions. For this project, Safety & Mission Assurance (S&MA) will work with Human Health & Performance (HH&P) to establish what is currently used to assess human reliabiilty for human space programs, identify human performance factors that may be sensitive to long duration space flight, collect available historical data, and update current tools to account for performance shaping factors believed to be important to such missions. This effort will also contribute data to the Human Performance Data Repository and influence the Space Human Factors Engineering research risks and gaps (part of the HRP Program). An accurate risk predictor mitigates Loss of Crew (LOC) and Loss of Mission (LOM).The end result will be an updated HRA model that can effectively predict risk on long-duration missions.

  19. Individual Differences in Human Reliability Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Jeffrey C. Joe; Ronald L. Boring

    2014-06-01

    While human reliability analysis (HRA) methods include uncertainty in quantification, the nominal model of human error in HRA typically assumes that operator performance does not vary significantly when they are given the same initiating event, indicators, procedures, and training, and that any differences in operator performance are simply aleatory (i.e., random). While this assumption generally holds true when performing routine actions, variability in operator response has been observed in multiple studies, especially in complex situations that go beyond training and procedures. As such, complexity can lead to differences in operator performance (e.g., operator understanding and decision-making). Furthermore, psychological research has shown that there are a number of known antecedents (i.e., attributable causes) that consistently contribute to observable and systematically measurable (i.e., not random) differences in behavior. This paper reviews examples of individual differences taken from operational experience and the psychological literature. The impact of these differences in human behavior and their implications for HRA are then discussed. We propose that individual differences should not be treated as aleatory, but rather as epistemic. Ultimately, by understanding the sources of individual differences, it is possible to remove some epistemic uncertainty from analyses.

  20. Advances in human reliability analysis in Mexico

    International Nuclear Information System (INIS)

    Nelson, Pamela F.; Gonzalez C, M.; Ruiz S, T.; Guillen M, D.; Contreras V, A.

    2010-10-01

    Human Reliability Analysis (HRA) is a very important part of Probabilistic Risk Analysis (PRA), and constant work is dedicated to improving methods, guidance and data in order to approach realism in the results as well as looking for ways to use these to reduce accident frequency at plants. Further, in order to advance in these areas, several HRA studies are being performed globally. Mexico has participated in the International HRA Empirical study with the objective of -benchmarking- HRA methods by comparing HRA predictions to actual crew performance in a simulator, as well as in the empirical study on a US nuclear power plant currently in progress. The focus of the first study was the development of an understanding of how methods are applied by various analysts, and characterize the methods for their capability to guide the analysts to identify potential human failures, and associated causes and performance shaping factors. The HRA benchmarking study has been performed by using the Halden simulator, 14 European crews, and 15 HRA equipment s (NRC, EPRI, and foreign HRA equipment s using different HRA methods). This effort in Mexico is reflected through the work being performed on updating the Laguna Verde PRA to comply with the ASME PRA standard. In order to be considered an HRA with technical adequacy, that is, be considered as a capability category II, for risk-informed applications, the methodology used for the HRA in the original PRA is not considered sufficiently detailed, and the methodology had to upgraded. The HCR/CBDT/THERP method was chosen, since this is used in many nuclear plants with similar design. The HRA update includes identification and evaluation of human errors that can occur during testing and maintenance, as well as human errors that can occur during an accident using the Emergency Operating Procedures. The review of procedures for maintenance, surveillance and operation is a necessary step in HRA and provides insight into the possible

  1. 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)

  2. RELIABILITY ANALYSIS OF POWER DISTRIBUTION SYSTEMS

    Directory of Open Access Journals (Sweden)

    Popescu V.S.

    2012-04-01

    Full Text Available Power distribution systems are basic parts of power systems and reliability of these systems at present is a key issue for power engineering development and requires special attention. Operation of distribution systems is accompanied by a number of factors that produce random data a large number of unplanned interruptions. Research has shown that the predominant factors that have a significant influence on the reliability of distribution systems are: weather conditions (39.7%, defects in equipment(25% and unknown random factors (20.1%. In the article is studied the influence of random behavior and are presented estimations of reliability of predominantly rural electrical distribution systems.

  3. Reliability

    OpenAIRE

    Condon, David; Revelle, William

    2017-01-01

    Separating the signal in a test from the irrelevant noise is a challenge for all measurement. Low test reliability limits test validity, attenuates important relationships, and can lead to regression artifacts. Multiple approaches to the assessment and improvement of reliability are discussed. The advantages and disadvantages of several different approaches to reliability are considered. Practical advice on how to assess reliability using open source software is provided.

  4. Reliability in perceptual analysis of voice quality.

    Science.gov (United States)

    Bele, Irene Velsvik

    2005-12-01

    This study focuses on speaking voice quality in male teachers (n = 35) and male actors (n = 36), who represent untrained and trained voice users, because we wanted to investigate normal and supranormal voices. In this study, both substantial and methodologic aspects were considered. It includes a method for perceptual voice evaluation, and a basic issue was rater reliability. A listening group of 10 listeners, 7 experienced speech-language therapists, and 3 speech-language therapist students evaluated the voices by 15 vocal characteristics using VA scales. Two sets of voice signals were investigated: text reading (2 loudness levels) and sustained vowel (3 levels). The results indicated a high interrater reliability for most perceptual characteristics. Connected speech was evaluated more reliably, especially at the normal level, but both types of voice signals were evaluated reliably, although the reliability for connected speech was somewhat higher than for vowels. Experienced listeners tended to be more consistent in their ratings than did the student raters. Some vocal characteristics achieved acceptable reliability even with a smaller panel of listeners. The perceptual characteristics grouped in 4 factors reflected perceptual dimensions.

  5. 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....

  6. 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

  7. 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.

  8. Reliability demonstration test planning using bayesian analysis

    International Nuclear Information System (INIS)

    Chandran, Senthil Kumar; Arul, John A.

    2003-01-01

    In Nuclear Power Plants, the reliability of all the safety systems is very critical from the safety viewpoint and it is very essential that the required reliability requirements be met while satisfying the design constraints. From practical experience, it is found that the reliability of complex systems such as Safety Rod Drive Mechanism is of the order of 10 -4 with an uncertainty factor of 10. To demonstrate the reliability of such systems is prohibitive in terms of cost and time as the number of tests needed is very large. The purpose of this paper is to develop a Bayesian reliability demonstrating testing procedure for exponentially distributed failure times with gamma prior distribution on the failure rate which can be easily and effectively used to demonstrate component/subsystem/system reliability conformance to stated requirements. The important questions addressed in this paper are: With zero failures, how long one should perform the tests and how many components are required to conclude with a given degree of confidence, that the component under test, meets the reliability requirement. The procedure is explained with an example. This procedure can also be extended to demonstrate with more number of failures. The approach presented is applicable for deriving test plans for demonstrating component failure rates of nuclear power plants, as the failure data for similar components are becoming available in existing plants elsewhere. The advantages of this procedure are the criterion upon which the procedure is based is simple and pertinent, the fitting of the prior distribution is an integral part of the procedure and is based on the use of information regarding two percentiles of this distribution and finally, the procedure is straightforward and easy to apply in practice. (author)

  9. Reliability analysis of pipe whip impacts

    International Nuclear Information System (INIS)

    Alzbutas, R.; Dundulis, G.; Kulak, R.F.; Marchertas, P.V.

    2003-01-01

    A probabilistic analysis of a group distribution header (GDH) guillotine break and the damage resulting from the failed GDH impacting against a neighbouring wall was carried out for the Ignalita RBMK-1500 reactor. The NEPTUNE software system was used for the deterministic transient analysis of a GDH guillotine break. Many deterministic analyses were performed using different values of the random variables that were specified by ProFES software. All the deterministic results were transferred to the ProFES system, which then performed probabilistic analyses of piping failure and wall damage. The Monte Carlo Simulation (MCS) method was used to study the sensitivity of the response variables and the effect of uncertainties of material properties and geometry parameters to the probability of limit states. The First Order Reliability Method (FORM) was used to study the probability of failure of the impacted-wall and the support-wall. The Response Surface (RS/MCS) method was used in order to express failure probability as function and to investigate the dependence between impact load and failure probability. The results of the probability analyses for a whipping GDH impacting onto an adjacent wall show that: (i) there is a 0.982 probability that after a GDH guillotine break contact between GDH and wall will occur; (ii) there is a probability of 0.013 that the ultimate tensile strength of concrete at the impact location will be reached, and a through-crack may open; (iii) there is a probability of 0.0126 that the ultimate compressive strength of concrete at the GDH support location will be reached, and the concrete may fail; (iv) at the impact location in the adjacent wall, there is a probability of 0.327 that the ultimate tensile strength of the rebars in the first layer will be reached and the rebars will fail; (v) at the GDH support location, there is a probability of 0.11 that the ultimate stress of the rebars in the first layer will be reached and the rebars will fail

  10. Tree-based server-middleman-client architecture: improving scalability and reliability for voting-based network games in ad hoc wireless networks

    Science.gov (United States)

    Guo, Y.; Fujinoki, H.

    2006-10-01

    The concept of a new tree-based architecture for networked multi-player games was proposed by Matuszek to improve scalability in network traffic at the same time to improve reliability. The architecture (we refer it as "Tree-Based Server- Middlemen-Client architecture") will solve the two major problems in ad-hoc wireless networks: frequent link failures and significance in battery power consumption at wireless transceivers by using two new techniques, recursive aggregation of client messages and subscription-based propagation of game state. However, the performance of the TBSMC architecture has never been quantitatively studied. In this paper, the TB-SMC architecture is compared with the client-server architecture using simulation experiments. We developed an event driven simulator to evaluate the performance of the TB-SMC architecture. In the network traffic scalability experiments, the TB-SMC architecture resulted in less than 1/14 of the network traffic load for 200 end users. In the reliability experiments, the TB-SMC architecture improved the number of successfully delivered players' votes by 31.6, 19.0, and 12.4% from the clientserver architecture at high (failure probability of 90%), moderate (50%) and low (10%) failure probability.

  11. 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)

  12. Time analysis of interconnection network implemented on the honeycomb architecture

    Energy Technology Data Exchange (ETDEWEB)

    Milutinovic, D [Inst. Michael Pupin, Belgrade (Yugoslavia)

    1996-12-31

    Problems of time domains analysis of the mapping of interconnection networks for parallel processing on one form of uniform massively parallel architecture of the cellular type are considered. The results of time analysis are discussed. It is found that changing the technology results in changing the mapping rules. 17 refs.

  13. A relational approach to support software architecture analysis

    NARCIS (Netherlands)

    Feijs, L.M.G.; Krikhaar, R.L.; van Ommering, R.C.

    1998-01-01

    This paper reports on our experience with a relational approach to support the analysis of existing software architectures. The analysis options provide for visualization and view calculation. The approach has been applied for reverse engineering. It is also possible to check concrete designs

  14. 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

  15. 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.

  16. Self-Healing Many-Core Architecture: Analysis and Evaluation

    Directory of Open Access Journals (Sweden)

    Arezoo Kamran

    2016-01-01

    Full Text Available More pronounced aging effects, more frequent early-life failures, and incomplete testing and verification processes due to time-to-market pressure in new fabrication technologies impose reliability challenges on forthcoming systems. A promising solution to these reliability challenges is self-test and self-reconfiguration with no or limited external control. In this work a scalable self-test mechanism for periodic online testing of many-core processor has been proposed. This test mechanism facilitates autonomous detection and omission of faulty cores and makes graceful degradation of the many-core architecture possible. Several test components are incorporated in the many-core architecture that distribute test stimuli, suspend normal operation of individual processing cores, apply test, and detect faulty cores. Test is performed concurrently with the system normal operation without any noticeable downtime at the application level. Experimental results show that the proposed test architecture is extensively scalable in terms of hardware overhead and performance overhead that makes it applicable to many-cores with more than a thousand processing cores.

  17. Performance Analysis of Cloud Computing Architectures Using Discrete Event Simulation

    Science.gov (United States)

    Stocker, John C.; Golomb, Andrew M.

    2011-01-01

    Cloud computing offers the economic benefit of on-demand resource allocation to meet changing enterprise computing needs. However, the flexibility of cloud computing is disadvantaged when compared to traditional hosting in providing predictable application and service performance. Cloud computing relies on resource scheduling in a virtualized network-centric server environment, which makes static performance analysis infeasible. We developed a discrete event simulation model to evaluate the overall effectiveness of organizations in executing their workflow in traditional and cloud computing architectures. The two part model framework characterizes both the demand using a probability distribution for each type of service request as well as enterprise computing resource constraints. Our simulations provide quantitative analysis to design and provision computing architectures that maximize overall mission effectiveness. We share our analysis of key resource constraints in cloud computing architectures and findings on the appropriateness of cloud computing in various applications.

  18. 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.

  19. 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.

  20. TIGER reliability analysis in the DSN

    Science.gov (United States)

    Gunn, J. M.

    1982-01-01

    The TIGER algorithm, the inputs to the program and the output are described. TIGER is a computer program designed to simulate a system over a period of time to evaluate system reliability and availability. Results can be used in the Deep Space Network for initial spares provisioning and system evaluation.

  1. Reliability analysis of an offshore structure

    DEFF Research Database (Denmark)

    Sorensen, J. D.; Faber, M. H.; Thoft-Christensen, P.

    1992-01-01

    A jacket type offshore structure from the North Sea is considered. The time variant reliability is estimated for failure defined as brittle fracture and crack through the tubular member walls. The stochastic modelling is described. The hot spot stress spectral moments as function of the stochasti...

  2. Reliability analysis of reactor protection systems

    International Nuclear Information System (INIS)

    Alsan, S.

    1976-07-01

    A theoretical mathematical study of reliability is presented and the concepts subsequently defined applied to the study of nuclear reactor safety systems. The theory is applied to investigations of the operational reliability of the Siloe reactor from the point of view of rod drop. A statistical study conducted between 1964 and 1971 demonstrated that most rod drop incidents arose from circumstances associated with experimental equipment (new set-ups). The reliability of the most suitable safety system for some recently developed experimental equipment is discussed. Calculations indicate that if all experimental equipment were equipped with these new systems, only 1.75 rod drop accidents would be expected to occur per year on average. It is suggested that all experimental equipment should be equipped with these new safety systems and tested every 21 days. The reliability of the new safety system currently being studied for the Siloe reactor was also investigated. The following results were obtained: definite failures must be detected immediately as a result of the disturbances produced; the repair time must not exceed a few hours; the equipment must be tested every week. Under such conditions, the rate of accidental rod drops is about 0.013 on average per year. The level of nondefinite failures is less than 10 -6 per hour and the level of nonprotection 1 hour per year. (author)

  3. Bypassing BDD Construction for Reliability Analysis

    DEFF Research Database (Denmark)

    Williams, Poul Frederick; Nikolskaia, Macha; Rauzy, Antoine

    2000-01-01

    In this note, we propose a Boolean Expression Diagram (BED)-based algorithm to compute the minimal p-cuts of boolean reliability models such as fault trees. BEDs make it possible to bypass the Binary Decision Diagram (BDD) construction, which is the main cost of fault tree assessment....

  4. 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)

  5. 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.

  6. 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

  7. Secure thin client architecture for DICOM image analysis

    Science.gov (United States)

    Mogatala, Harsha V. R.; Gallet, Jacqueline

    2005-04-01

    This paper presents a concept of Secure Thin Client (STC) Architecture for Digital Imaging and Communications in Medicine (DICOM) image analysis over Internet. STC Architecture provides in-depth analysis and design of customized reports for DICOM images using drag-and-drop and data warehouse technology. Using a personal computer and a common set of browsing software, STC can be used for analyzing and reporting detailed patient information, type of examinations, date, Computer Tomography (CT) dose index, and other relevant information stored within the images header files as well as in the hospital databases. STC Architecture is three-tier architecture. The First-Tier consists of drag-and-drop web based interface and web server, which provides customized analysis and reporting ability to the users. The Second-Tier consists of an online analytical processing (OLAP) server and database system, which serves fast, real-time, aggregated multi-dimensional data using OLAP technology. The Third-Tier consists of a smart algorithm based software program which extracts DICOM tags from CT images in this particular application, irrespective of CT vendor's, and transfers these tags into a secure database system. This architecture provides Winnipeg Regional Health Authorities (WRHA) with quality indicators for CT examinations in the hospitals. It also provides health care professionals with analytical tool to optimize radiation dose and image quality parameters. The information is provided to the user by way of a secure socket layer (SSL) and role based security criteria over Internet. Although this particular application has been developed for WRHA, this paper also discusses the effort to extend the Architecture to other hospitals in the region. Any DICOM tag from any imaging modality could be tracked with this software.

  8. Reliability analysis of PLC safety equipment

    Energy Technology Data Exchange (ETDEWEB)

    Yu, J.; Kim, J. Y. [Chungnam Nat. Univ., Daejeon (Korea, Republic of)

    2006-06-15

    FMEA analysis for Nuclear Safety Grade PLC, failure rate prediction for nuclear safety grade PLC, sensitivity analysis for components failure rate of nuclear safety grade PLC, unavailability analysis support for nuclear safety system.

  9. Reliability analysis of PLC safety equipment

    International Nuclear Information System (INIS)

    Yu, J.; Kim, J. Y.

    2006-06-01

    FMEA analysis for Nuclear Safety Grade PLC, failure rate prediction for nuclear safety grade PLC, sensitivity analysis for components failure rate of nuclear safety grade PLC, unavailability analysis support for nuclear safety system

  10. Automated Energy Distribution and Reliability System: Validation Integration - Results of Future Architecture Implementation

    Energy Technology Data Exchange (ETDEWEB)

    Buche, D. L.

    2008-06-01

    This report describes Northern Indiana Public Service Co. project efforts to develop an automated energy distribution and reliability system. The purpose of this project was to implement a database-driven GIS solution that would manage all of the company's gas, electric, and landbase objects. This report is second in a series of reports detailing this effort.

  11. 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

  12. Digital Architecture – Results From a Gap Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Oxstrand, Johanna Helene [Idaho National Lab. (INL), Idaho Falls, ID (United States); Thomas, Kenneth David [Idaho National Lab. (INL), Idaho Falls, ID (United States); Fitzgerald, Kirk [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-09-01

    The digital architecture is defined as a collection of IT capabilities needed to support and integrate a wide-spectrum of real-time digital capabilities for nuclear power plant performance improvements. The digital architecture can be thought of as an integration of the separate I&C and information systems already in place in NPPs, brought together for the purpose of creating new levels of automation in NPP work activities. In some cases, it might be an extension of the current communication systems, to provide digital communications where they are currently analog only. This collection of IT capabilities must in turn be based on a set of user requirements that must be supported for the interconnected technologies to operate in an integrated manner. These requirements, simply put, are a statement of what sorts of digital work functions will be exercised in a fully-implemented seamless digital environment and how much they will be used. The goal of the digital architecture research is to develop a methodology for mapping nuclear power plant operational and support activities into the digital architecture, which includes the development of a consensus model for advanced information and control architecture. The consensus model should be developed at a level of detail that is useful to the industry. In other words, not so detailed that it specifies specific protocols and not so vague that it is only provides a high level description of technology. The next step towards the model development is to determine the current state of digital architecture at typical NPPs. To investigate the current state, the researchers conducted a gap analysis to determine to what extent the NPPs can support the future digital technology environment with their existing I&C and IT structure, and where gaps exist with respect to the full deployment of technology over time. The methodology, result, and conclusions from the gap analysis are described in this report.

  13. 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

  14. 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.

  15. A systematic review and meta-analysis of sleep architecture and chronic traumatic brain injury.

    Science.gov (United States)

    Mantua, Janna; Grillakis, Antigone; Mahfouz, Sanaa H; Taylor, Maura R; Brager, Allison J; Yarnell, Angela M; Balkin, Thomas J; Capaldi, Vincent F; Simonelli, Guido

    2018-02-02

    Sleep quality appears to be altered by traumatic brain injury (TBI). However, whether persistent post-injury changes in sleep architecture are present is unknown and relatively unexplored. We conducted a systematic review and meta-analysis to assess the extent to which chronic TBI (>6 months since injury) is characterized by changes to sleep architecture. We also explored the relationship between sleep architecture and TBI severity. In the fourteen included studies, sleep was assessed with at least one night of polysomnography in both chronic TBI participants and controls. Statistical analyses, performed using Comprehensive Meta-Analysis software, revealed that chronic TBI is characterized by relatively increased slow wave sleep (SWS). A meta-regression showed moderate-severe TBI is associated with elevated SWS, reduced stage 2, and reduced sleep efficiency. In contrast, mild TBI was not associated with any significant alteration of sleep architecture. The present findings are consistent with the hypothesis that increased SWS after moderate-severe TBI reflects post-injury cortical reorganization and restructuring. Suggestions for future research are discussed, including adoption of common data elements in future studies to facilitate cross-study comparability, reliability, and replicability, thereby increasing the likelihood that meaningful sleep (and other) biomarkers of TBI will be identified. Copyright © 2018 Elsevier Ltd. All rights reserved.

  16. Structural reliability analysis applied to pipeline risk analysis

    Energy Technology Data Exchange (ETDEWEB)

    Gardiner, M. [GL Industrial Services, Loughborough (United Kingdom); Mendes, Renato F.; Donato, Guilherme V.P. [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil)

    2009-07-01

    Quantitative Risk Assessment (QRA) of pipelines requires two main components to be provided. These are models of the consequences that follow from some loss of containment incident, and models for the likelihood of such incidents occurring. This paper describes how PETROBRAS have used Structural Reliability Analysis for the second of these, to provide pipeline- and location-specific predictions of failure frequency for a number of pipeline assets. This paper presents an approach to estimating failure rates for liquid and gas pipelines, using Structural Reliability Analysis (SRA) to analyze the credible basic mechanisms of failure such as corrosion and mechanical damage. SRA is a probabilistic limit state method: for a given failure mechanism it quantifies the uncertainty in parameters to mathematical models of the load-resistance state of a structure and then evaluates the probability of load exceeding resistance. SRA can be used to benefit the pipeline risk management process by optimizing in-line inspection schedules, and as part of the design process for new construction in pipeline rights of way that already contain multiple lines. A case study is presented to show how the SRA approach has recently been used on PETROBRAS pipelines and the benefits obtained from it. (author)

  17. 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

  18. 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

  19. 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.

  20. 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.

  1. 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.

  2. 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

  3. Reliability analysis applied to structural tests

    Science.gov (United States)

    Diamond, P.; Payne, A. O.

    1972-01-01

    The application of reliability theory to predict, from structural fatigue test data, the risk of failure of a structure under service conditions because its load-carrying capability is progressively reduced by the extension of a fatigue crack, is considered. The procedure is applicable to both safe-life and fail-safe structures and, for a prescribed safety level, it will enable an inspection procedure to be planned or, if inspection is not feasible, it will evaluate the life to replacement. The theory has been further developed to cope with the case of structures with initial cracks, such as can occur in modern high-strength materials which are susceptible to the formation of small flaws during the production process. The method has been applied to a structure of high-strength steel and the results are compared with those obtained by the current life estimation procedures. This has shown that the conventional methods can be unconservative in certain cases, depending on the characteristics of the structure and the design operating conditions. The suitability of the probabilistic approach to the interpretation of the results from full-scale fatigue testing of aircraft structures is discussed and the assumptions involved are examined.

  4. Tiger Teams Technical Assistance: Reliable, Universal Open Architecture for Card Access to Dispense Alternative Fuels

    Energy Technology Data Exchange (ETDEWEB)

    2002-03-01

    Report discusses the dilemma of incorporating consistent, convenient, universal card access (or ''pay-at-the-pump'') systems into alternative fueling stations across the country. The state of California continues to be in the forefront of implementing alternative fuels for transportation applications. Aggressive efforts to deploy alternative fuel vehicles (AFVs) in California have highlighted the need to provide adequate fueling stations and develop appropriate, user-friendly means to purchase fuel at the pump. Since these fuels are not typically provided by petroleum companies at conventional fueling stations, and acceptance of cash is often not an option, a payment method must be developed that is consistent with the way individual AFV operators are accustomed to purchasing automotive fuels--with a credit card. At the same time, large fleets like the California Department of General Services must be able to use a single fuel card that offers comprehensive fleet management services. The Gas Technology Institute's Infrastructure Working Group (IWG) and its stakeholders have identified the lack of a common card reader system as a hurdle to wider deployment of AFVs in California and the United States. In conjunction with the U.S. Department of Energy's (DOE) National Clean Cities Program, the IWG has outlined a multi-phased strategy to systematically address the barriers to develop a more ''open'' architecture that's similar to the way gasoline and diesel are currently dispensed. Under the auspices of the IWG, survey results were gathered (circa 1999) from certain fuel providers, as a means to more carefully study card reader issues and their potential solutions. Pilot programs featuring card reader systems capable of accepting wider payment options have been attempted in several regions of the United States with mixed success. In early 2001, DOE joined the National Renewable Energy Laboratory (NREL), the

  5. Application of DFM in human reliability analysis

    International Nuclear Information System (INIS)

    Yu Shaojie; Zhao Jun; Tong Jiejuan

    2011-01-01

    Combining with ATHEANA, the possible to identify EFCs and UAs using DFM is studied; and then Steam Generator Tube Rupture (SGTR) accident is modeled and solved. Through inductive analysis, 26 Prime Implicants (PIs) are obtained and the meaning of results is interpreted; and one of PIs is similar to the accident scenario of human failure event in one nuclear power plant. Finally, this paper discusses the methods of quantifying PIs, analysis of Error of commission (EOC) and so on. (authors)

  6. 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.)

  7. 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...

  8. 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)

  9. 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

  10. 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.)

  11. 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) ...

  12. Human reliability analysis in Loviisa probabilistic safety analysis

    International Nuclear Information System (INIS)

    Illman, L.; Isaksson, J.; Makkonen, L.; Vaurio, J.K.; Vuorio, U.

    1986-01-01

    The human reliability analysis in the Loviisa PSA project is carried out for three major groups of errors in human actions: (A) errors made before an initiating event, (B) errors that initiate a transient and (C) errors made during transients. Recovery possibilities are also included in each group. The methods used or planned for each group are described. A simplified THERP approach is used for group A, with emphasis on test and maintenance error recovery aspects and dependencies between redundancies. For group B, task analyses and human factors assessments are made for startup, shutdown and operational transients, with emphasis on potential common cause initiators. For group C, both misdiagnosis and slow decision making are analyzed, as well as errors made in carrying out necessary or backup actions. New or advanced features of the methodology are described

  13. 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

  14. Statis Program Analysis for Reliable, Trusted Apps

    Science.gov (United States)

    2017-02-01

    and prevent errors in their Java programs. The Checker Framework includes compiler plug-ins (“checkers”) that find bugs or verify their absence. It...versions of the Java language. 4.8 DATAFLOW FRAMEWORK The dataflow framework enables more accurate analysis of source code. (Despite their similar...names, the dataflow framework is independent of the (Information) Flow Checker of chapter 2.) In Java code, a given operation may be permitted or

  15. Specification, Design, and Analysis of Advanced HUMS Architectures

    Science.gov (United States)

    Mukkamala, Ravi

    2004-01-01

    During the two-year project period, we have worked on several aspects of domain-specific architectures for HUMS. In particular, we looked at using scenario-based approach for the design and designed a language for describing such architectures. The language is now being used in all aspects of our HUMS design. In particular, we have made contributions in the following areas. 1) We have employed scenarios in the development of HUMS in three main areas. They are: (a) To improve reusability by using scenarios as a library indexing tool and as a domain analysis tool; (b) To improve maintainability by recording design rationales from two perspectives - problem domain and solution domain; (c) To evaluate the software architecture. 2) We have defined a new architectural language called HADL or HUMS Architectural Definition Language. It is a customized version of xArch/xADL. It is based on XML and, hence, is easily portable from domain to domain, application to application, and machine to machine. Specifications written in HADL can be easily read and parsed using the currently available XML parsers. Thus, there is no need to develop a plethora of software to support HADL. 3) We have developed an automated design process that involves two main techniques: (a) Selection of solutions from a large space of designs; (b) Synthesis of designs. However, the automation process is not an absolute Artificial Intelligence (AI) approach though it uses a knowledge-based system that epitomizes a specific HUMS domain. The process uses a database of solutions as an aid to solve the problems rather than creating a new design in the literal sense. Since searching is adopted as the main technique, the challenges involved are: (a) To minimize the effort in searching the database where a very large number of possibilities exist; (b) To develop representations that could conveniently allow us to depict design knowledge evolved over many years; (c) To capture the required information that aid the

  16. AN ARCHITECTURAL ANALYSIS: THE MUSEUM OF CONTEMPORARY ART, TEHRAN, IRAN

    Directory of Open Access Journals (Sweden)

    Kambiz Navai

    2010-03-01

    Full Text Available Kamran Tabatabai Diba is one of Iranian Architects, whose works during 60’s and 70’s are well-known among architects and scholars. His works are mostly considered as examples of Modern Style, scented by Iranian Architecture. His efforts on creating public, socio-cultural centers in Iran was a result of his concern about social matters, as well as seeking for a national, contemporary Architecture. Tehran’s Museum of Contemporary Art is one of the most popular and well-known Diba’s works. In this article an effort has been made to get a better understanding of this remarkable piece of work, and to light up the Architect’s intents and the architectural methods he used to express them. The critique is concentrated mostly on two mentioned aspects of Diba’s works: “Integrating Modern Style and traditional Iranian Architecture”, and “Creating socio-cultural centers and institutions well related to society.” The Analysis is based on the most important features of every work of Architecture: “Space” and “Form”. The author seeks for the meaning by “watching” the whole complex carefully, “giving descriptive information” about it, and in the meantime “analyzing data” with the help of “basic design methods” together with the knowledge of “Modern Style”, “Characteristics of Late Modern Movement” and “Traditional Iranian Architecture.” Text is accompanied by drawings and figures, which help for better knowing the complex. The effort is made to use a simple language, understandable not only by Architects or scholars, but by every other interested non-specialist reader.

  17. 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.

  18. 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.

  19. 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...

  20. Reliability analysis of dispersion nuclear fuel elements

    Science.gov (United States)

    Ding, Shurong; Jiang, Xin; Huo, Yongzhong; Li, Lin an

    2008-03-01

    Taking a dispersion fuel element as a special particle composite, the representative volume element is chosen to act as the research object. The fuel swelling is simulated through temperature increase. The large strain elastoplastic analysis is carried out for the mechanical behaviors using FEM. The results indicate that the fission swelling is simulated successfully; the thickness increments grow linearly with burnup; with increasing of burnup: (1) the first principal stresses at fuel particles change from tensile ones to compression ones, (2) the maximum Mises stresses at the particles transfer from the centers of fuel particles to the location close to the interfaces between the matrix and the particles, their values increase with burnup; the maximum Mises stresses at the matrix exist in the middle location between the two particles near the mid-plane along the length (or width) direction, and the maximum plastic strains are also at the above region.

  1. Reliability analysis of dispersion nuclear fuel elements

    Energy Technology Data Exchange (ETDEWEB)

    Ding Shurong [Department of Mechanics and Engineering Science, Fudan University, Shanghai 200433 (China)], E-mail: dsr1971@163.com; Jiang Xin [Department of Mechanics and Engineering Science, Fudan University, Shanghai 200433 (China); Huo Yongzhong [Department of Mechanics and Engineering Science, Fudan University, Shanghai 200433 (China)], E-mail: yzhuo@fudan.edu.cn; Li Linan [Department of Mechanics, Tianjin University, Tianjin 300072 (China)

    2008-03-15

    Taking a dispersion fuel element as a special particle composite, the representative volume element is chosen to act as the research object. The fuel swelling is simulated through temperature increase. The large strain elastoplastic analysis is carried out for the mechanical behaviors using FEM. The results indicate that the fission swelling is simulated successfully; the thickness increments grow linearly with burnup; with increasing of burnup: (1) the first principal stresses at fuel particles change from tensile ones to compression ones, (2) the maximum Mises stresses at the particles transfer from the centers of fuel particles to the location close to the interfaces between the matrix and the particles, their values increase with burnup; the maximum Mises stresses at the matrix exist in the middle location between the two particles near the mid-plane along the length (or width) direction, and the maximum plastic strains are also at the above region.

  2. Advanced information processing system: The Army fault tolerant architecture conceptual study. Volume 2: Army fault tolerant architecture design and analysis

    Science.gov (United States)

    Harper, R. E.; Alger, L. S.; Babikyan, C. A.; Butler, B. P.; Friend, S. A.; Ganska, R. J.; Lala, J. H.; Masotto, T. K.; Meyer, A. J.; Morton, D. P.

    1992-01-01

    Described here is the Army Fault Tolerant Architecture (AFTA) hardware architecture and components and the operating system. The architectural and operational theory of the AFTA Fault Tolerant Data Bus is discussed. The test and maintenance strategy developed for use in fielded AFTA installations is presented. An approach to be used in reducing the probability of AFTA failure due to common mode faults is described. Analytical models for AFTA performance, reliability, availability, life cycle cost, weight, power, and volume are developed. An approach is presented for using VHSIC Hardware Description Language (VHDL) to describe and design AFTA's developmental hardware. A plan is described for verifying and validating key AFTA concepts during the Dem/Val phase. Analytical models and partial mission requirements are used to generate AFTA configurations for the TF/TA/NOE and Ground Vehicle missions.

  3. A software architectural framework specification for neutron activation analysis

    International Nuclear Information System (INIS)

    Preston, J.A.; Grant, C.N.

    2013-01-01

    Neutron Activation Analysis (NAA) is a sensitive multi-element nuclear analytical technique that has been routinely applied by research reactor (RR) facilities to environmental, nutritional, health related, geological and geochemical studies. As RR facilities face calls to increase their research output and impact, with existing or reducing budgets, automation of NAA offers a possible solution. However, automation has many challenges, not the least of which is a lack of system architecture standards to establish acceptable mechanisms for the various hardware/software and software/software interactions among data acquisition systems, specialised hardware such as sample changers, sample loaders, and data processing modules. This lack of standardization often results in automation hardware and software being incompatible with existing system components, in a facility looking to automate its NAA operations. This limits the availability of automation to a few RR facilities with adequate budgets or in-house engineering resources. What is needed is a modern open system architecture for NAA, that provides the required set of functionalities. This paper describes such an 'architectural framework' (OpenNAA), and portions of a reference implementation. As an example of the benefits, calculations indicate that applying this architecture to the compilation and QA steps associated with the analysis of 35 elements in 140 samples, with 14 SRM's, can reduce the time required by over 80 %. The adoption of open standards in the nuclear industry has been very successful over the years in promoting interchangeability and maximising the lifetime and output of nuclear measurement systems. OpenNAA will provide similar benefits within the NAA application space, safeguarding user investments in their current system, while providing a solid path for development into the future. (author)

  4. 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.

  5. 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.)

  6. 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

  7. 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

  8. 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....

  9. 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

  10. Design and reliability, availability, maintainability, and safety analysis of a high availability quadruple vital computer system

    Institute of Scientific and Technical Information of China (English)

    Ping TAN; Wei-ting HE; Jia LIN; Hong-ming ZHAO; Jian CHU

    2011-01-01

    With the development of high-speed railways in China,more than 2000 high-speed trains will be put into use.Safety and efficiency of railway transportation is increasingly important.We have designed a high availability quadruple vital computer (HAQVC) system based on the analysis of the architecture of the traditional double 2-out-of-2 system and 2-out-of-3 system.The HAQVC system is a system with high availability and safety,with prominent characteristics such as fire-new internal architecture,high efficiency,reliable data interaction mechanism,and operation state change mechanism.The hardware of the vital CPU is based on ARM7 with the real-time embedded safe operation system (ES-OS).The Markov modeling method is designed to evaluate the reliability,availability,maintainability,and safety (RAMS) of the system.In this paper,we demonstrate that the HAQVC system is more reliable than the all voting triple modular redundancy (AVTMR) system and double 2-out-of-2 system.Thus,the design can be used for a specific application system,such as an airplane or high-speed railway system.

  11. Reliability modeling and analysis for a novel design of modular converter system of wind turbines

    International Nuclear Information System (INIS)

    Zhang, Cai Wen; Zhang, Tieling; Chen, Nan; Jin, Tongdan

    2013-01-01

    Converters play a vital role in wind turbines. The concept of modularity is gaining in popularity in converter design for modern wind turbines in order to achieve high reliability as well as cost-effectiveness. In this study, we are concerned with a novel topology of modular converter invented by Hjort, Modular converter system with interchangeable converter modules. World Intellectual Property Organization, Pub. No. WO29027520 A2; 5 March 2009, in this architecture, the converter comprises a number of identical and interchangeable basic modules. Each module can operate in either AC/DC or DC/AC mode, depending on whether it functions on the generator or the grid side. Moreover, each module can be reconfigured from one side to the other, depending on the system’s operational requirements. This is a shining example of full-modular design. This paper aims to model and analyze the reliability of such a modular converter. A Markov modeling approach is applied to the system reliability analysis. In particular, six feasible converter system models based on Hjort’s architecture are investigated. Through numerical analyses and comparison, we provide insights and guidance for converter designers in their decision-making.

  12. 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

  13. 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.

  14. 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....

  15. Reliability Analysis of a Two Dissimilar Unit Cold Standby System ...

    African Journals Online (AJOL)

    (2009) using linear first order differential equation evaluated the reliability and availability characteristics of two-dissimilar-unit cold standby system with three mode for which no cost benefit analysis was considered. El-said (1994) contributed on stochastic analysis of a two-dissimilar-unit standby redundant system.

  16. 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.

  17. 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

  18. 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)

  19. 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.)

  20. 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.

  1. 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

  2. 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...

  3. 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

  4. 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

  5. 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.

  6. 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.

  7. 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

  8. Quantitative analysis of the epithelial lining architecture in radicular cysts and odontogenic keratocysts

    Directory of Open Access Journals (Sweden)

    Landini Gabriel

    2006-02-01

    Full Text Available Abstract Background This paper describes a quantitative analysis of the cyst lining architecture in radicular cysts (of inflammatory aetiology and odontogenic keratocysts (thought to be developmental or neoplastic including its 2 counterparts: solitary and associated with the Basal Cell Naevus Syndrome (BCNS. Methods Epithelial linings from 150 images (from 9 radicular cysts, 13 solitary keratocysts and 8 BCNS keratocysts were segmented into theoretical cells using a semi-automated partition based on the intensity of the haematoxylin stain which defined exclusive areas relative to each detected nucleus. Various morphometrical parameters were extracted from these "cells" and epithelial layer membership was computed using a systematic clustering routine. Results Statistically significant differences were observed across the 3 cyst types both at the morphological and architectural levels of the lining. Case-wise discrimination between radicular cysts and keratocyst was highly accurate (with an error of just 3.3%. However, the odontogenic keratocyst subtypes could not be reliably separated into the original classes, achieving discrimination rates slightly above random allocations (60%. Conclusion The methodology presented is able to provide new measures of epithelial architecture and may help to characterise and compare tissue spatial organisation as well as provide useful procedures for automating certain aspects of histopathological diagnosis.

  9. 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).

  10. Reliability analysis of reactor inspection robot(RIROB)

    International Nuclear Information System (INIS)

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

    2002-05-01

    This report describes the method and the result of the reliability analysis of RIROB developed in Korea Atomic Energy Research Institute. There are many classic techniques and models for the reliability analysis. These techniques and models have been used widely and approved in other industries such as aviation and nuclear industry. Though these techniques and models have been approved in real fields they are still insufficient for the complicated systems such RIROB which are composed of computer, networks, electronic parts, mechanical parts, and software. Particularly the application of these analysis techniques to digital and software parts of complicated systems is immature at this time thus expert judgement plays important role in evaluating the reliability of the systems at these days. In this report we proposed a method which combines diverse evidences relevant to the reliability to evaluate the reliability of complicated systems such as RIROB. The proposed method combines diverse evidences and performs inference in formal and in quantitative way by using the benefits of Bayesian Belief Nets (BBN)

  11. 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....

  12. Enterprise architecture availability analysis using fault trees and stakeholder interviews

    Science.gov (United States)

    Närman, Per; Franke, Ulrik; König, Johan; Buschle, Markus; Ekstedt, Mathias

    2014-01-01

    The availability of enterprise information systems is a key concern for many organisations. This article describes a method for availability analysis based on Fault Tree Analysis and constructs from the ArchiMate enterprise architecture (EA) language. To test the quality of the method, several case-studies within the banking and electrical utility industries were performed. Input data were collected through stakeholder interviews. The results from the case studies were compared with availability of log data to determine the accuracy of the method's predictions. In the five cases where accurate log data were available, the yearly downtime estimates were within eight hours from the actual downtimes. The cost of performing the analysis was low; no case study required more than 20 man-hours of work, making the method ideal for practitioners with an interest in obtaining rapid availability estimates of their enterprise information systems.

  13. 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.

  14. 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.

  15. 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)

  16. 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

  17. 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

  18. System Reliability Analysis Capability and Surrogate Model Application in RAVEN

    Energy Technology Data Exchange (ETDEWEB)

    Rabiti, Cristian [Idaho National Lab. (INL), Idaho Falls, ID (United States); Alfonsi, Andrea [Idaho National Lab. (INL), Idaho Falls, ID (United States); Huang, Dongli [Idaho National Lab. (INL), Idaho Falls, ID (United States); Gleicher, Frederick [Idaho National Lab. (INL), Idaho Falls, ID (United States); Wang, Bei [Idaho National Lab. (INL), Idaho Falls, ID (United States); Adbel-Khalik, Hany S. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Pascucci, Valerio [Idaho National Lab. (INL), Idaho Falls, ID (United States); Smith, Curtis L. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-11-01

    This report collect the effort performed to improve the reliability analysis capabilities of the RAVEN code and explore new opportunity in the usage of surrogate model by extending the current RAVEN capabilities to multi physics surrogate models and construction of surrogate models for high dimensionality fields.

  19. Factorial validation and reliability analysis of the brain fag syndrome ...

    African Journals Online (AJOL)

    Results: Two valid factors emerged with items 1-3 and items 4, 5 & 7 loading on respectively, making the BFSS a twodimensional (multidimensional) scale which measures 2 aspects of brain fag [labeled burning sensation and crawling sensation respectively]. The reliability analysis yielded a Cronbach Alpha coefficient of ...

  20. Semivariogram Analysis of Bone Images Implemented on FPGA Architectures.

    Science.gov (United States)

    Shirvaikar, Mukul; Lagadapati, Yamuna; Dong, Xuanliang

    2017-03-01

    Osteoporotic fractures are a major concern for the healthcare of elderly and female populations. Early diagnosis of patients with a high risk of osteoporotic fractures can be enhanced by introducing second-order statistical analysis of bone image data using techniques such as variogram analysis. Such analysis is computationally intensive thereby creating an impediment for introduction into imaging machines found in common clinical settings. This paper investigates the fast implementation of the semivariogram algorithm, which has been proven to be effective in modeling bone strength, and should be of interest to readers in the areas of computer-aided diagnosis and quantitative image analysis. The semivariogram is a statistical measure of the spatial distribution of data, and is based on Markov Random Fields (MRFs). Semivariogram analysis is a computationally intensive algorithm that has typically seen applications in the geosciences and remote sensing areas. Recently, applications in the area of medical imaging have been investigated, resulting in the need for efficient real time implementation of the algorithm. A semi-variance, γ ( h ), is defined as the half of the expected squared differences of pixel values between any two data locations with a lag distance of h . Due to the need to examine each pair of pixels in the image or sub-image being processed, the base algorithm complexity for an image window with n pixels is O ( n 2 ) Field Programmable Gate Arrays (FPGAs) are an attractive solution for such demanding applications due to their parallel processing capability. FPGAs also tend to operate at relatively modest clock rates measured in a few hundreds of megahertz. This paper presents a technique for the fast computation of the semivariogram using two custom FPGA architectures. A modular architecture approach is chosen to allow for replication of processing units. This allows for high throughput due to concurrent processing of pixel pairs. The current

  1. 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

  2. ZERBERUS - the code for reliability analysis of crack containing structures

    International Nuclear Information System (INIS)

    Cizelj, L.; Riesch-Oppermann, H.

    1992-04-01

    Brief description of the First- and Second Order Reliability Methods, being the theoretical background of the code, is given. The code structure is described in detail, with special emphasis to the new application fields. The numerical example investigates failure probability of steam generator tubing affected by stress corrosion cracking. The changes necessary to accommodate this analysis within the ZERBERUS code are explained. Analysis results are compared to different Monte Carlo techniques. (orig./HP) [de

  3. 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.

  4. 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

  5. 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.

  6. 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.

  7. TAD-free analysis of architectural proteins and insulators.

    Science.gov (United States)

    Mourad, Raphaël; Cuvier, Olivier

    2018-03-16

    The three-dimensional (3D) organization of the genome is intimately related to numerous key biological functions including gene expression and DNA replication regulations. The mechanisms by which molecular drivers functionally organize the 3D genome, such as topologically associating domains (TADs), remain to be explored. Current approaches consist in assessing the enrichments or influences of proteins at TAD borders. Here, we propose a TAD-free model to directly estimate the blocking effects of architectural proteins, insulators and DNA motifs on long-range contacts, making the model intuitive and biologically meaningful. In addition, the model allows analyzing the whole Hi-C information content (2D information) instead of only focusing on TAD borders (1D information). The model outperforms multiple logistic regression at TAD borders in terms of parameter estimation accuracy and is validated by enhancer-blocking assays. In Drosophila, the results support the insulating role of simple sequence repeats and suggest that the blocking effects depend on the number of repeats. Motif analysis uncovered the roles of the transcriptional factors pannier and tramtrack in blocking long-range contacts. In human, the results suggest that the blocking effects of the well-known architectural proteins CTCF, cohesin and ZNF143 depend on the distance between loci, where each protein may participate at different scales of the 3D chromatin organization.

  8. Analysis of the Reliability of the "Alternator- Alternator Belt" System

    Directory of Open Access Journals (Sweden)

    Ivan Mavrin

    2012-10-01

    Full Text Available Before starting and also during the exploitation of va1ioussystems, it is vety imp011ant to know how the system and itsparts will behave during operation regarding breakdowns, i.e.failures. It is possible to predict the service behaviour of a systemby determining the functions of reliability, as well as frequencyand intensity of failures.The paper considers the theoretical basics of the functionsof reliability, frequency and intensity of failures for the twomain approaches. One includes 6 equal intetvals and the other13 unequal intetvals for the concrete case taken from practice.The reliability of the "alternator- alternator belt" system installedin the buses, has been analysed, according to the empiricaldata on failures.The empitical data on failures provide empirical functionsof reliability and frequency and intensity of failures, that arepresented in tables and graphically. The first analysis perfO!med by dividing the mean time between failures into 6 equaltime intervals has given the forms of empirical functions of fa ilurefrequency and intensity that approximately cotTespond totypical functions. By dividing the failure phase into 13 unequalintetvals with two failures in each interval, these functions indicateexplicit transitions from early failure inte1val into the randomfailure interval, i.e. into the ageing intetval. Functions thusobtained are more accurate and represent a better solution forthe given case.In order to estimate reliability of these systems with greateraccuracy, a greater number of failures needs to be analysed.

  9. 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.

  10. 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)

  11. 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

  12. 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)

  13. Analysis of Different Blade Architectures on small VAWT Performance

    Science.gov (United States)

    Battisti, L.; Brighenti, A.; Benini, E.; Raciti Castelli, M.

    2016-09-01

    The present paper aims at describing and comparing different small Vertical Axis Wind Turbine (VAWT) architectures, in terms of performance and loads. These characteristics can be highlighted by resorting to the Blade Element-Momentum (BE-M) model, commonly adopted for rotor pre-design and controller assessment. After validating the model with experimental data, the paper focuses on the analysis of VAWT loads depending on some relevant rotor features: blade number (2 and 3), airfoil camber line (comparing symmetrical and asymmetrical profiles) and blade inclination (straight versus helical blade). The effect of such characteristics on both power and thrusts (in the streamwise direction and in the crosswise one) as a function of both the blades azimuthal position and their Tip Speed Ratio (TSR) are presented and widely discussed.

  14. Finite Element Analysis of Film Stack Architecture for Complementary Metal-Oxide-Semiconductor Image Sensors.

    Science.gov (United States)

    Wu, Kuo-Tsai; Hwang, Sheng-Jye; Lee, Huei-Huang

    2017-05-02

    Image sensors are the core components of computer, communication, and consumer electronic products. Complementary metal oxide semiconductor (CMOS) image sensors have become the mainstay of image-sensing developments, but are prone to leakage current. In this study, we simulate the CMOS image sensor (CIS) film stacking process by finite element analysis. To elucidate the relationship between the leakage current and stack architecture, we compare the simulated and measured leakage currents in the elements. Based on the analysis results, we further improve the performance by optimizing the architecture of the film stacks or changing the thin-film material. The material parameters are then corrected to improve the accuracy of the simulation results. The simulated and experimental results confirm a positive correlation between measured leakage current and stress. This trend is attributed to the structural defects induced by high stress, which generate leakage. Using this relationship, we can change the structure of the thin-film stack to reduce the leakage current and thereby improve the component life and reliability of the CIS components.

  15. 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

  16. Analysis and primary design of the I and C system architecture for HTGR-10 reactor

    International Nuclear Information System (INIS)

    Yang Zijue; Zhao Guoji

    1993-01-01

    The consideration of making good use of the-state-of-the-arts technology in designing advanced Instrumentation and Control System architecture is discussed. A fully distributed and fully micro-computerized, local network based Instrumentation and Control System is designed for the HTR-10 reactor. The advantages of the system architecture include high reliability and availability, flexibility, economics, etc. It also fits for other production processes

  17. Point Cloud Analysis for Conservation and Enhancement of Modernist Architecture

    Science.gov (United States)

    Balzani, M.; Maietti, F.; Mugayar Kühl, B.

    2017-02-01

    Documentation of cultural assets through improved acquisition processes for advanced 3D modelling is one of the main challenges to be faced in order to address, through digital representation, advanced analysis on shape, appearance and conservation condition of cultural heritage. 3D modelling can originate new avenues in the way tangible cultural heritage is studied, visualized, curated, displayed and monitored, improving key features such as analysis and visualization of material degradation and state of conservation. An applied research focused on the analysis of surface specifications and material properties by means of 3D laser scanner survey has been developed within the project of Digital Preservation of FAUUSP building, Faculdade de Arquitetura e Urbanismo da Universidade de São Paulo, Brazil. The integrated 3D survey has been performed by the DIAPReM Center of the Department of Architecture of the University of Ferrara in cooperation with the FAUUSP. The 3D survey has allowed the realization of a point cloud model of the external surfaces, as the basis to investigate in detail the formal characteristics, geometric textures and surface features. The digital geometric model was also the basis for processing the intensity values acquired by laser scanning instrument; this method of analysis was an essential integration to the macroscopic investigations in order to manage additional information related to surface characteristics displayable on the point cloud.

  18. 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

  19. 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

  20. 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

  1. 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.

  2. 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.

  3. Reliability analysis with linguistic data: An evidential network approach

    International Nuclear Information System (INIS)

    Zhang, Xiaoge; Mahadevan, Sankaran; Deng, Xinyang

    2017-01-01

    In practical applications of reliability assessment of a system in-service, information about the condition of a system and its components is often available in text form, e.g., inspection reports. Estimation of the system reliability from such text-based records becomes a challenging problem. In this paper, we propose a four-step framework to deal with this problem. In the first step, we construct an evidential network with the consideration of available knowledge and data. Secondly, we train a Naive Bayes text classification algorithm based on the past records. By using the trained Naive Bayes algorithm to classify the new records, we build interval basic probability assignments (BPA) for each new record available in text form. Thirdly, we combine the interval BPAs of multiple new records using an evidence combination approach based on evidence theory. Finally, we propagate the interval BPA through the evidential network constructed earlier to obtain the system reliability. Two numerical examples are used to demonstrate the efficiency of the proposed method. We illustrate the effectiveness of the proposed method by comparing with Monte Carlo Simulation (MCS) results. - Highlights: • We model reliability analysis with linguistic data using evidential network. • Two examples are used to demonstrate the efficiency of the proposed method. • We compare the results with Monte Carlo Simulation (MCS).

  4. 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').

  5. 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.

  6. Some developments in human reliability analysis approaches and tools

    Energy Technology Data Exchange (ETDEWEB)

    Hannaman, G W; Worledge, D H

    1988-01-01

    Since human actions have been recognized as an important contributor to safety of operating plants in most industries, research has been performed to better understand and account for the way operators interact during accidents through the control room and equipment interface. This paper describes the integration of a series of research projects sponsored by the Electric Power Research Institute to strengthen the methods for performing the human reliability analysis portion of the probabilistic safety studies. It focuses on the analytical framework used to guide the analysis, the development of the models for quantifying time-dependent actions, and simulator experiments used to validate the models.

  7. 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

  8. RGCA: A Reliable GPU Cluster Architecture for Large-Scale Internet of Things Computing Based on Effective Performance-Energy Optimization.

    Science.gov (United States)

    Fang, Yuling; Chen, Qingkui; Xiong, Neal N; Zhao, Deyu; Wang, Jingjuan

    2017-08-04

    This paper aims to develop a low-cost, high-performance and high-reliability computing system to process large-scale data using common data mining algorithms in the Internet of Things (IoT) computing environment. Considering the characteristics of IoT data processing, similar to mainstream high performance computing, we use a GPU (Graphics Processing Unit) cluster to achieve better IoT services. Firstly, we present an energy consumption calculation method (ECCM) based on WSNs. Then, using the CUDA (Compute Unified Device Architecture) Programming model, we propose a Two-level Parallel Optimization Model (TLPOM) which exploits reasonable resource planning and common compiler optimization techniques to obtain the best blocks and threads configuration considering the resource constraints of each node. The key to this part is dynamic coupling Thread-Level Parallelism (TLP) and Instruction-Level Parallelism (ILP) to improve the performance of the algorithms without additional energy consumption. Finally, combining the ECCM and the TLPOM, we use the Reliable GPU Cluster Architecture (RGCA) to obtain a high-reliability computing system considering the nodes' diversity, algorithm characteristics, etc. The results show that the performance of the algorithms significantly increased by 34.1%, 33.96% and 24.07% for Fermi, Kepler and Maxwell on average with TLPOM and the RGCA ensures that our IoT computing system provides low-cost and high-reliability services.

  9. A comparative reliability analysis of free-piston Stirling machines

    Science.gov (United States)

    Schreiber, Jeffrey G.

    2001-02-01

    A free-piston Stirling power convertor is being developed for use in an advanced radioisotope power system to provide electric power for NASA deep space missions. These missions are typically long lived, lasting for up to 14 years. The Department of Energy (DOE) is responsible for providing the radioisotope power system for the NASA missions, and has managed the development of the free-piston power convertor for this application. The NASA Glenn Research Center has been involved in the development of Stirling power conversion technology for over 25 years and is currently providing support to DOE. Due to the nature of the potential missions, long life and high reliability are important features for the power system. Substantial resources have been spent on the development of long life Stirling cryocoolers for space applications. As a very general statement, free-piston Stirling power convertors have many features in common with free-piston Stirling cryocoolers, however there are also significant differences. For example, designs exist for both power convertors and cryocoolers that use the flexure bearing support system to provide noncontacting operation of the close-clearance moving parts. This technology and the operating experience derived from one application may be readily applied to the other application. This similarity does not pertain in the case of outgassing and contamination. In the cryocooler, the contaminants normally condense in the critical heat exchangers and foul the performance. In the Stirling power convertor just the opposite is true as contaminants condense on non-critical surfaces. A methodology was recently published that provides a relative comparison of reliability, and is applicable to systems. The methodology has been applied to compare the reliability of a Stirling cryocooler relative to that of a free-piston Stirling power convertor. The reliability analysis indicates that the power convertor should be able to have superior reliability

  10. 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)

  11. 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.

  12. 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....

  13. 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

  14. Reliability analysis of offshore structures using OMA based fatigue stresses

    DEFF Research Database (Denmark)

    Silva Nabuco, Bruna; Aissani, Amina; Glindtvad Tarpø, Marius

    2017-01-01

    focus is on the uncertainty observed on the different stresses used to predict the damage. This uncertainty can be reduced by Modal Based Fatigue Monitoring which is a technique based on continuously measuring of the accelerations in few points of the structure with the use of accelerometers known...... points of the structure, the stress history can be calculated in any arbitrary point of the structure. The accuracy of the estimated actual stress is analyzed by experimental tests on a scale model where the obtained stresses are compared to strain gauges measurements. After evaluating the fatigue...... stresses directly from the operational response of the structure, a reliability analysis is performed in order to estimate the reliability of using Modal Based Fatigue Monitoring for long term fatigue studies....

  15. 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)

  16. Issues in benchmarking human reliability analysis methods: A literature review

    International Nuclear Information System (INIS)

    Boring, Ronald L.; Hendrickson, Stacey M.L.; Forester, John A.; Tran, Tuan Q.; Lois, Erasmia

    2010-01-01

    There is a diversity of human reliability analysis (HRA) methods available for use in assessing human performance within probabilistic risk assessments (PRA). Due to the significant differences in the methods, including the scope, approach, and underlying models, there is a need for an empirical comparison investigating the validity and reliability of the methods. To accomplish this empirical comparison, a benchmarking study comparing and evaluating HRA methods in assessing operator performance in simulator experiments is currently underway. In order to account for as many effects as possible in the construction of this benchmarking study, a literature review was conducted, reviewing past benchmarking studies in the areas of psychology and risk assessment. A number of lessons learned through these studies is presented in order to aid in the design of future HRA benchmarking endeavors.

  17. Photovoltaic module reliability improvement through application testing and failure analysis

    Science.gov (United States)

    Dumas, L. N.; Shumka, A.

    1982-01-01

    During the first four years of the U.S. Department of Energy (DOE) National Photovoltatic Program, the Jet Propulsion Laboratory Low-Cost Solar Array (LSA) Project purchased about 400 kW of photovoltaic modules for test and experiments. In order to identify, report, and analyze test and operational problems with the Block Procurement modules, a problem/failure reporting and analysis system was implemented by the LSA Project with the main purpose of providing manufacturers with feedback from test and field experience needed for the improvement of product performance and reliability. A description of the more significant types of failures is presented, taking into account interconnects, cracked cells, dielectric breakdown, delamination, and corrosion. Current design practices and reliability evaluations are also discussed. The conducted evaluation indicates that current module designs incorporate damage-resistant and fault-tolerant features which address field failure mechanisms observed to date.

  18. Mechanical Properties for Reliability Analysis of Structures in Glassy Carbon

    CERN Document Server

    Garion, Cédric

    2014-01-01

    Despite its good physical properties, the glassy carbon material is not widely used, especially for structural applications. Nevertheless, its transparency to particles and temperature resistance are interesting properties for the applications to vacuum chambers and components in high energy physics. For example, it has been proposed for fast shutter valve in particle accelerator [1] [2]. The mechanical properties have to be carefully determined to assess the reliability of structures in such a material. In this paper, mechanical tests have been carried out to determine the elastic parameters, the strength and toughness on commercial grades. A statistical approach, based on the Weibull’s distribution, is used to characterize the material both in tension and compression. The results are compared to the literature and the difference of properties for these two loading cases is shown. Based on a Finite Element analysis, a statistical approach is applied to define the reliability of a structural component in gl...

  19. User's manual of a support system for human reliability analysis

    International Nuclear Information System (INIS)

    Yokobayashi, Masao; Tamura, Kazuo.

    1995-10-01

    Many kinds of human reliability analysis (HRA) methods have been developed. However, users are required to be skillful so as to use them, and also required complicated works such as drawing event tree (ET) and calculation of uncertainty bounds. Moreover, each method is not so complete that only one method of them is not enough to evaluate human reliability. Therefore, a personal computer (PC) based support system for HRA has been developed to execute HRA practically and efficiently. The system consists of two methods, namely, simple method and detailed one. The former uses ASEP that is a simplified THERP-technique, and combined method of OAT and HRA-ET/DeBDA is used for the latter. Users can select a suitable method for their purpose. Human error probability (HEP) data were collected and a database of them was built to use for the support system. This paper describes outline of the HRA methods, support functions and user's guide of the system. (author)

  20. Issues in benchmarking human reliability analysis methods : a literature review.

    Energy Technology Data Exchange (ETDEWEB)

    Lois, Erasmia (US Nuclear Regulatory Commission); Forester, John Alan; Tran, Tuan Q. (Idaho National Laboratory, Idaho Falls, ID); Hendrickson, Stacey M. Langfitt; Boring, Ronald L. (Idaho National Laboratory, Idaho Falls, ID)

    2008-04-01

    There is a diversity of human reliability analysis (HRA) methods available for use in assessing human performance within probabilistic risk assessment (PRA). Due to the significant differences in the methods, including the scope, approach, and underlying models, there is a need for an empirical comparison investigating the validity and reliability of the methods. To accomplish this empirical comparison, a benchmarking study is currently underway that compares HRA methods with each other and against operator performance in simulator studies. In order to account for as many effects as possible in the construction of this benchmarking study, a literature review was conducted, reviewing past benchmarking studies in the areas of psychology and risk assessment. A number of lessons learned through these studies are presented in order to aid in the design of future HRA benchmarking endeavors.

  1. Review of the treat upgrade reactor scram system reliability analysis

    International Nuclear Information System (INIS)

    Montague, D.F.; Fussell, J.B.; Krois, P.A.; Morelock, T.C.; Knee, H.E.; Manning, J.J.; Haas, P.M.; West, K.W.

    1984-10-01

    In order to resolve some key LMFBR safety issues, ANL personnel are modifying the TREAT reactor to handle much larger experiments. As a result of these modifications, the upgraded Treat reactor will not always operate in a self-limited mode. During certain experiments in the upgraded TREAT reactor, it is possible that the fuel could be damaged by overheating if, once the computer systems fail, the reactor scram system (RSS) fails on demand. To help ensure that the upgraded TREAT reactor is shut down when required, ANL personnel have designed a triply redundant RSS for the facility. The RSS is designed to meet three reliability goals: (1) a loss of capability failure probability of 10 -9 /demand (independent failures only); (2) an inadvertent shutdown probability of 10 -3 /experiment; and (3) protection agaist any known potential common cause failures. According to ANL's reliability analysis of the RSS, this system substantially meets these goals

  2. Virtual Prototyping and Performance Analysis of Two Memory Architectures

    Directory of Open Access Journals (Sweden)

    Huda S. Muhammad

    2009-01-01

    Full Text Available The gap between CPU and memory speed has always been a critical concern that motivated researchers to study and analyze the performance of memory hierarchical architectures. In the early stages of the design cycle, performance evaluation methodologies can be used to leverage exploration at the architectural level and assist in making early design tradeoffs. In this paper, we use simulation platforms developed using the VisualSim tool to compare the performance of two memory architectures, namely, the Direct Connect architecture of the Opteron, and the Shared Bus of the Xeon multicore processors. Key variations exist between the two memory architectures and both design approaches provide rich platforms that call for the early use of virtual system prototyping and simulation techniques to assess performance at an early stage in the design cycle.

  3. Genome-wide analysis of promoter architecture in Drosophila melanogaster

    Energy Technology Data Exchange (ETDEWEB)

    Hoskins, Roger A.; Landolin, Jane M.; Brown, James B.; Sandler, Jeremy E.; Takahashi, Hazuki; Lassmann, Timo; Yu, Charles; Booth, Benjamin W.; Zhang, Dayu; Wan, Kenneth H.; Yang, Li; Boley, Nathan; Andrews, Justen; Kaufman, Thomas C.; Graveley, Brenton R.; Bickel, Peter J.; Carninci, Piero; Carlson, Joseph W.; Celniker, Susan E.

    2010-10-20

    Core promoters are critical regions for gene regulation in higher eukaryotes. However, the boundaries of promoter regions, the relative rates of initiation at the transcription start sites (TSSs) distributed within them, and the functional significance of promoter architecture remain poorly understood. We produced a high-resolution map of promoters active in the Drosophila melanogaster embryo by integrating data from three independent and complementary methods: 21 million cap analysis of gene expression (CAGE) tags, 1.2 million RNA ligase mediated rapid amplification of cDNA ends (RLMRACE) reads, and 50,000 cap-trapped expressed sequence tags (ESTs). We defined 12,454 promoters of 8037 genes. Our analysis indicates that, due to non-promoter-associated RNA background signal, previous studies have likely overestimated the number of promoter-associated CAGE clusters by fivefold. We show that TSS distributions form a complex continuum of shapes, and that promoters active in the embryo and adult have highly similar shapes in 95% of cases. This suggests that these distributions are generally determined by static elements such as local DNA sequence and are not modulated by dynamic signals such as histone modifications. Transcription factor binding motifs are differentially enriched as a function of promoter shape, and peaked promoter shape is correlated with both temporal and spatial regulation of gene expression. Our results contribute to the emerging view that core promoters are functionally diverse and control patterning of gene expression in Drosophila and mammals.

  4. 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...

  5. 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

  6. Design and Analysis of Architectures for Structural Health Monitoring Systems

    Science.gov (United States)

    Mukkamala, Ravi; Sixto, S. L. (Technical Monitor)

    2002-01-01

    During the two-year project period, we have worked on several aspects of Health Usage and Monitoring Systems for structural health monitoring. In particular, we have made contributions in the following areas. 1. Reference HUMS architecture: We developed a high-level architecture for health monitoring and usage systems (HUMS). The proposed reference architecture is shown. It is compatible with the Generic Open Architecture (GOA) proposed as a standard for avionics systems. 2. HUMS kernel: One of the critical layers of HUMS reference architecture is the HUMS kernel. We developed a detailed design of a kernel to implement the high level architecture.3. Prototype implementation of HUMS kernel: We have implemented a preliminary version of the HUMS kernel on a Unix platform.We have implemented both a centralized system version and a distributed version. 4. SCRAMNet and HUMS: SCRAMNet (Shared Common Random Access Memory Network) is a system that is found to be suitable to implement HUMS. For this reason, we have conducted a simulation study to determine its stability in handling the input data rates in HUMS. 5. Architectural specification.

  7. A Research Roadmap for Computation-Based Human Reliability Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Boring, Ronald [Idaho National Lab. (INL), Idaho Falls, ID (United States); Mandelli, Diego [Idaho National Lab. (INL), Idaho Falls, ID (United States); Joe, Jeffrey [Idaho National Lab. (INL), Idaho Falls, ID (United States); Smith, Curtis [Idaho National Lab. (INL), Idaho Falls, ID (United States); Groth, Katrina [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-08-01

    The United States (U.S.) Department of Energy (DOE) is sponsoring research through the Light Water Reactor Sustainability (LWRS) program to extend the life of the currently operating fleet of commercial nuclear power plants. The Risk Informed Safety Margin Characterization (RISMC) research pathway within LWRS looks at ways to maintain and improve the safety margins of these plants. The RISMC pathway includes significant developments in the area of thermalhydraulics code modeling and the development of tools to facilitate dynamic probabilistic risk assessment (PRA). PRA is primarily concerned with the risk of hardware systems at the plant; yet, hardware reliability is often secondary in overall risk significance to human errors that can trigger or compound undesirable events at the plant. This report highlights ongoing efforts to develop a computation-based approach to human reliability analysis (HRA). This computation-based approach differs from existing static and dynamic HRA approaches in that it: (i) interfaces with a dynamic computation engine that includes a full scope plant model, and (ii) interfaces with a PRA software toolset. The computation-based HRA approach presented in this report is called the Human Unimodels for Nuclear Technology to Enhance Reliability (HUNTER) and incorporates in a hybrid fashion elements of existing HRA methods to interface with new computational tools developed under the RISMC pathway. The goal of this research effort is to model human performance more accurately than existing approaches, thereby minimizing modeling uncertainty found in current plant risk models.

  8. A Research Roadmap for Computation-Based Human Reliability Analysis

    International Nuclear Information System (INIS)

    Boring, Ronald; Mandelli, Diego; Joe, Jeffrey; Smith, Curtis; Groth, Katrina

    2015-01-01

    The United States (U.S.) Department of Energy (DOE) is sponsoring research through the Light Water Reactor Sustainability (LWRS) program to extend the life of the currently operating fleet of commercial nuclear power plants. The Risk Informed Safety Margin Characterization (RISMC) research pathway within LWRS looks at ways to maintain and improve the safety margins of these plants. The RISMC pathway includes significant developments in the area of thermalhydraulics code modeling and the development of tools to facilitate dynamic probabilistic risk assessment (PRA). PRA is primarily concerned with the risk of hardware systems at the plant; yet, hardware reliability is often secondary in overall risk significance to human errors that can trigger or compound undesirable events at the plant. This report highlights ongoing efforts to develop a computation-based approach to human reliability analysis (HRA). This computation-based approach differs from existing static and dynamic HRA approaches in that it: (i) interfaces with a dynamic computation engine that includes a full scope plant model, and (ii) interfaces with a PRA software toolset. The computation-based HRA approach presented in this report is called the Human Unimodels for Nuclear Technology to Enhance Reliability (HUNTER) and incorporates in a hybrid fashion elements of existing HRA methods to interface with new computational tools developed under the RISMC pathway. The goal of this research effort is to model human performance more accurately than existing approaches, thereby minimizing modeling uncertainty found in current plant risk models.

  9. Limitations in simulator time-based human reliability analysis methods

    International Nuclear Information System (INIS)

    Wreathall, J.

    1989-01-01

    Developments in human reliability analysis (HRA) methods have evolved slowly. Current methods are little changed from those of almost a decade ago, particularly in the use of time-reliability relationships. While these methods were suitable as an interim step, the time (and the need) has come to specify the next evolution of HRA methods. As with any performance-oriented data source, power plant simulator data have no direct connection to HRA models. Errors reported in data are normal deficiencies observed in human performance; failures are events modeled in probabilistic risk assessments (PRAs). Not all errors cause failures; not all failures are caused by errors. Second, the times at which actions are taken provide no measure of the likelihood of failures to act correctly within an accident scenario. Inferences can be made about human reliability, but they must be made with great care. Specific limitations are discussed. Simulator performance data are useful in providing qualitative evidence of the variety of error types and their potential influences on operating systems. More work is required to combine recent developments in the psychology of error with the qualitative data collected at stimulators. Until data become openly available, however, such an advance will not be practical

  10. The DYLAM approach for the dynamic reliability analysis of systems

    International Nuclear Information System (INIS)

    Cojazzi, Giacomo

    1996-01-01

    In many real systems, failures occurring to the components, control failures and human interventions often interact with the physical system evolution in such a way that a simple reliability analysis, de-coupled from process dynamics, is very difficult or even impossible. In the last ten years many dynamic reliability approaches have been proposed to properly assess the reliability of these systems characterized by dynamic interactions. The DYLAM methodology, now implemented in its latest version, DYLAM-3, offers a powerful tool for integrating deterministic and failure events. This paper describes the main features of the DYLAM-3 code with reference to the classic fault-tree and event-tree techniques. Some aspects connected to the practical problems underlying dynamic event-trees are also discussed. A simple system, already analyzed with other dynamic methods is used as a reference for the numerical applications. The same system is also studied with a time-dependent fault-tree approach in order to show some features of dynamic methods vs classical techniques. Examples including stochastic failures, without and with repair, failures on demand and time dependent failure rates give an extensive overview of DYLAM-3 capabilities

  11. Hardware Architectures for the Correspondence Problem in Image Analysis

    DEFF Research Database (Denmark)

    Paulsen, Thomas Eide

    Method"has been developed in conjunction with the work on this thesis and has not previously been described. Also, during this project a combined image acquisition and compression board has been developed for a NASA sounding rocket. This circuit, a so-called Lightning Imager, is also described. Finally...... an optimized hardware architecture has been proposed in relation to the three matching methods mentioned above. Because of the cost required to physically implement and test the developed architecture, it has been decided todocument the performance of the architecture through theoretical proofs only....

  12. 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)

  13. Failure and Reliability Analysis for the Master Pump Shutdown System

    International Nuclear Information System (INIS)

    BEVINS, R.R.

    2000-01-01

    The Master Pump Shutdown System (MPSS) will be installed in the 200 Areas of the Hanford Site to monitor and control the transfer of liquid waste between tank farms and between the 200 West and 200 East areas through the Cross-Site Transfer Line. The Safety Function provided by the MPSS is to shutdown any waste transfer process within or between tank farms if a waste leak should occur along the selected transfer route. The MPSS, which provides this Safety Class Function, is composed of Programmable Logic Controllers (PLCs), interconnecting wires, relays, Human to Machine Interfaces (HMI), and software. These components are defined as providing a Safety Class Function and will be designated in this report as MPSS/PLC. Input signals to the MPSS/PLC are provided by leak detection systems from each of the tank farm leak detector locations along the waste transfer route. The combination of the MPSS/PLC, leak detection system, and transfer pump controller system will be referred to as MPSS/SYS. The components addressed in this analysis are associated with the MPSS/SYS. The purpose of this failure and reliability analysis is to address the following design issues of the Project Development Specification (PDS) for the MPSS/SYS (HNF 2000a): (1) Single Component Failure Criterion, (2) System Status Upon Loss of Electrical Power, (3) Physical Separation of Safety Class cables, (4) Physical Isolation of Safety Class Wiring from General Service Wiring, and (5) Meeting the MPSS/PLC Option 1b (RPP 1999) Reliability estimate. The failure and reliability analysis examined the system on a component level basis and identified any hardware or software elements that could fail and/or prevent the system from performing its intended safety function

  14. 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.

  15. Reliability and Robustness Analysis of the Masinga Dam under Uncertainty

    Directory of Open Access Journals (Sweden)

    Hayden Postle-Floyd

    2017-02-01

    Full Text Available Kenya’s water abstraction must meet the projected growth in municipal and irrigation demand by the end of 2030 in order to achieve the country’s industrial and economic development plan. The Masinga dam, on the Tana River, is the key to meeting this goal to satisfy the growing demands whilst also continuing to provide hydroelectric power generation. This study quantitatively assesses the reliability and robustness of the Masinga dam system under uncertain future supply and demand using probabilistic climate and population projections, and examines how long-term planning may improve the longevity of the dam. River flow and demand projections are used alongside each other as inputs to the dam system simulation model linked to an optimisation engine to maximise water availability. Water availability after demand satisfaction is assessed for future years, and the projected reliability of the system is calculated for selected years. The analysis shows that maximising power generation on a short-term year-by-year basis achieves 80%, 50% and 1% reliability by 2020, 2025 and 2030 onwards, respectively. Longer term optimal planning, however, has increased system reliability to up to 95% in 2020, 80% in 2025, and more than 40% in 2030 onwards. In addition, increasing the capacity of the reservoir by around 25% can significantly improve the robustness of the system for all future time periods. This study provides a platform for analysing the implication of different planning and management of Masinga dam and suggests that careful consideration should be given to account for growing municipal needs and irrigation schemes in both the immediate and the associated Tana River basin.

  16. Reliability analysis of structures under periodic proof tests in service

    Science.gov (United States)

    Yang, J.-N.

    1976-01-01

    A reliability analysis of structures subjected to random service loads and periodic proof tests treats gust loads and maneuver loads as random processes. Crack initiation, crack propagation, and strength degradation are treated as the fatigue process. The time to fatigue crack initiation and ultimate strength are random variables. Residual strength decreases during crack propagation, so that failure rate increases with time. When a structure fails under periodic proof testing, a new structure is built and proof-tested. The probability of structural failure in service is derived from treatment of all the random variables, strength degradations, service loads, proof tests, and the renewal of failed structures. Some numerical examples are worked out.

  17. Creation and Reliability Analysis of Vehicle Dynamic Weighing Model

    Directory of Open Access Journals (Sweden)

    Zhi-Ling XU

    2014-08-01

    Full Text Available In this paper, it is modeled by using ADAMS to portable axle load meter of dynamic weighing system, controlling a single variable simulation weighing process, getting the simulation weighing data under the different speed and weight; simultaneously using portable weighing system with the same parameters to achieve the actual measurement, comparative analysis the simulation results under the same conditions, at 30 km/h or less, the simulation value and the measured value do not differ by more than 5 %, it is not only to verify the reliability of dynamic weighing model, but also to create possible for improving algorithm study efficiency by using dynamic weighing model simulation.

  18. Human Performance Modeling for Dynamic Human Reliability Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Boring, Ronald Laurids [Idaho National Laboratory; Joe, Jeffrey Clark [Idaho National Laboratory; Mandelli, Diego [Idaho National Laboratory

    2015-08-01

    Part of the U.S. Department of Energy’s (DOE’s) Light Water Reac- tor Sustainability (LWRS) Program, the Risk-Informed Safety Margin Charac- terization (RISMC) Pathway develops approaches to estimating and managing safety margins. RISMC simulations pair deterministic plant physics models with probabilistic risk models. As human interactions are an essential element of plant risk, it is necessary to integrate human actions into the RISMC risk framework. In this paper, we review simulation based and non simulation based human reliability analysis (HRA) methods. This paper summarizes the founda- tional information needed to develop a feasible approach to modeling human in- teractions in RISMC simulations.

  19. IDHEAS – A NEW APPROACH FOR HUMAN RELIABILITY ANALYSIS

    Energy Technology Data Exchange (ETDEWEB)

    G. W. Parry; J.A Forester; V.N. Dang; S. M. L. Hendrickson; M. Presley; E. Lois; J. Xing

    2013-09-01

    This paper describes a method, IDHEAS (Integrated Decision-Tree Human Event Analysis System) that has been developed jointly by the US NRC and EPRI as an improved approach to Human Reliability Analysis (HRA) that is based on an understanding of the cognitive mechanisms and performance influencing factors (PIFs) that affect operator responses. The paper describes the various elements of the method, namely the performance of a detailed cognitive task analysis that is documented in a crew response tree (CRT), and the development of the associated time-line to identify the critical tasks, i.e. those whose failure results in a human failure event (HFE), and an approach to quantification that is based on explanations of why the HFE might occur.

  20. Decay assessment through thermographic analysis in architectural and archaeological heritage

    Science.gov (United States)

    Gomez-Heras, Miguel; Martinez-Perez, Laura; Fort, Rafael; Alvarez de Buergo, Monica

    2010-05-01

    Any exposed stone-built structure is subject to thermal variations due to daily, seasonal and secular environmental temperature changes. Surface temperature is a function of air temperature (due to convective heat transfer) and of infrared radiation received through insolation. While convective heat transfer homogenizes surface temperature, stone response to insolation is much more complex and the temporal and spatial temperature differences across structures are enhanced. Surface temperature in stone-built structures will be affected by orientation, sunlight inclination and the complex patterns of light and shadows generated by the often intricate morphology of historical artefacts and structures. Surface temperature will also be affected by different material properties, such as albedo, thermal conductivity, transparency and absorbance to infrared radiation of minerals and rocks. Moisture and the occurrence of salts will also be a factor affecting surface temperatures. Surface temperatures may as well be affected by physical disruptions of rocks due to differences in thermal inertia generated by cracks and other discontinuities. Thermography is a non-invasive, non-destructive technique that measures temperature variations on the surface of a material. With this technique, surface temperature rates of change and their spatial variations can be analysed. This analysis may be used not only to evaluate the incidence of thermal decay as a factor that generates or enhances stone decay, but also to detect and evaluate other factors that affect the state of conservation of architectural and archaeological heritage, as for example moisture, salts or mechanical disruptions.

  1. Cyber threat impact assessment and analysis for space vehicle architectures

    Science.gov (United States)

    McGraw, Robert M.; Fowler, Mark J.; Umphress, David; MacDonald, Richard A.

    2014-06-01

    This paper covers research into an assessment of potential impacts and techniques to detect and mitigate cyber attacks that affect the networks and control systems of space vehicles. Such systems, if subverted by malicious insiders, external hackers and/or supply chain threats, can be controlled in a manner to cause physical damage to the space platforms. Similar attacks on Earth-borne cyber physical systems include the Shamoon, Duqu, Flame and Stuxnet exploits. These have been used to bring down foreign power generation and refining systems. This paper discusses the potential impacts of similar cyber attacks on space-based platforms through the use of simulation models, including custom models developed in Python using SimPy and commercial SATCOM analysis tools, as an example STK/SOLIS. The paper discusses the architecture and fidelity of the simulation model that has been developed for performing the impact assessment. The paper walks through the application of an attack vector at the subsystem level and how it affects the control and orientation of the space vehicle. SimPy is used to model and extract raw impact data at the bus level, while STK/SOLIS is used to extract raw impact data at the subsystem level and to visually display the effect on the physical plant of the space vehicle.

  2. Architecture survey analysis by CSA initiative : volume I final report

    Science.gov (United States)

    1993-07-01

    Many organizations in industry and government, face challenges in information management similar to the Federal Aviation Administration (FAA). The objective of the Architecture Survey is to enable the FAA to build upon the experience and technical co...

  3. Analysis and proposal of the new architecture of the selected parts of the software support of the COMPASS experiment

    CERN Document Server

    Jary, Vladimir

    This work focuses on the data acquisition system of the Compass experiment at CERN. At first the database current subsystem that suffered from increased load during year 2009 is analysed. The reasons of problems are identified and new architecture that includes replication, backups, and monitoring for achieving the high availability and reliability is proposed and implemented. Several advanced database features including partitioned tables or storage engines are described and tested. Then, the process of implementation of the remote control and monitoring of the experiment is explained. As the existing data acquisition system is partly based on a deprecated technologies, development of a new architecture has started. We focus on requirements analysis and proposal of a control and monitoring software for the new hardware platform based on the FPGA technology. The software is to be deployed in a heterogenous network environment. According to the proposal, the system is built on the DIM communication library. Ro...

  4. Tailoring a Human Reliability Analysis to Your Industry Needs

    Science.gov (United States)

    DeMott, D. L.

    2016-01-01

    Companies at risk of accidents caused by human error that result in catastrophic consequences include: airline industry mishaps, medical malpractice, medication mistakes, aerospace failures, major oil spills, transportation mishaps, power production failures and manufacturing facility incidents. Human Reliability Assessment (HRA) is used to analyze the inherent risk of human behavior or actions introducing errors into the operation of a system or process. These assessments can be used to identify where errors are most likely to arise and the potential risks involved if they do occur. Using the basic concepts of HRA, an evolving group of methodologies are used to meet various industry needs. Determining which methodology or combination of techniques will provide a quality human reliability assessment is a key element to developing effective strategies for understanding and dealing with risks caused by human errors. There are a number of concerns and difficulties in "tailoring" a Human Reliability Assessment (HRA) for different industries. Although a variety of HRA methodologies are available to analyze human error events, determining the most appropriate tools to provide the most useful results can depend on industry specific cultures and requirements. Methodology selection may be based on a variety of factors that include: 1) how people act and react in different industries, 2) expectations based on industry standards, 3) factors that influence how the human errors could occur such as tasks, tools, environment, workplace, support, training and procedure, 4) type and availability of data, 5) how the industry views risk & reliability, and 6) types of emergencies, contingencies and routine tasks. Other considerations for methodology selection should be based on what information is needed from the assessment. If the principal concern is determination of the primary risk factors contributing to the potential human error, a more detailed analysis method may be employed

  5. 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.

  6. 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

  7. 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.

  8. Analysis of Employment Flow of Landscape Architecture Graduates in Agricultural Universities

    Science.gov (United States)

    Yao, Xia; He, Linchun

    2012-01-01

    A statistical analysis of employment flow of landscape architecture graduates was conducted on the employment data of graduates major in landscape architecture in 2008 to 2011. The employment flow of graduates was to be admitted to graduate students, industrial direction and regional distribution, etc. Then, the features of talent flow and factors…

  9. Analysis of dependent failures in risk assessment and reliability evaluation

    International Nuclear Information System (INIS)

    Fleming, K.N.; Mosleh, A.; Kelley, A.P. Jr.; Gas-Cooled Reactors Associates, La Jolla, CA)

    1983-01-01

    The ability to estimate the risk of potential reactor accidents is largely determined by the ability to analyze statistically dependent multiple failures. The importance of dependent failures has been indicated in recent probabilistic risk assessment (PRA) studies as well as in reports of reactor operating experiences. This article highlights the importance of several different types of dependent failures from the perspective of the risk and reliability analyst and provides references to the methods and data available for their analysis. In addition to describing the current state of the art, some recent advances, pitfalls, misconceptions, and limitations of some approaches to dependent failure analysis are addressed. A summary is included of the discourse on this subject, which is presented in the Institute of Electrical and Electronics Engineers/American Nuclear Society PRA Procedures Guide

  10. Model-based human reliability analysis: prospects and requirements

    International Nuclear Information System (INIS)

    Mosleh, A.; Chang, Y.H.

    2004-01-01

    Major limitations of the conventional methods for human reliability analysis (HRA), particularly those developed for operator response analysis in probabilistic safety assessments (PSA) of nuclear power plants, are summarized as a motivation for the need and a basis for developing requirements for the next generation HRA methods. It is argued that a model-based approach that provides explicit cognitive causal links between operator behaviors and directly or indirectly measurable causal factors should be at the core of the advanced methods. An example of such causal model is briefly reviewed, where due to the model complexity and input requirements can only be currently implemented in a dynamic PSA environment. The computer simulation code developed for this purpose is also described briefly, together with current limitations in the models, data, and the computer implementation

  11. Current Human Reliability Analysis Methods Applied to Computerized Procedures

    Energy Technology Data Exchange (ETDEWEB)

    Ronald L. Boring

    2012-06-01

    Computerized procedures (CPs) are an emerging technology within nuclear power plant control rooms. While CPs have been implemented internationally in advanced control rooms, to date no US nuclear power plant has implemented CPs in its main control room (Fink et al., 2009). Yet, CPs are a reality of new plant builds and are an area of considerable interest to existing plants, which see advantages in terms of enhanced ease of use and easier records management by omitting the need for updating hardcopy procedures. The overall intent of this paper is to provide a characterization of human reliability analysis (HRA) issues for computerized procedures. It is beyond the scope of this document to propose a new HRA approach or to recommend specific methods or refinements to those methods. Rather, this paper serves as a review of current HRA as it may be used for the analysis and review of computerized procedures.

  12. Standardization of domestic human reliability analysis and experience of human reliability analysis in probabilistic safety assessment for NPPs under design

    International Nuclear Information System (INIS)

    Kang, D. I.; Jung, W. D.

    2002-01-01

    This paper introduces the background and development activities of domestic standardization of procedure and method for Human Reliability Analysis (HRA) to avoid the intervention of subjectivity by HRA analyst in Probabilistic Safety Assessment (PSA) as possible, and the review of the HRA results for domestic nuclear power plants under design studied by Korea Atomic Energy Research Institute. We identify the HRA methods used for PSA for domestic NPPs and discuss the subjectivity of HRA analyst shown in performing a HRA. Also, we introduce the PSA guidelines published in USA and review the HRA results based on them. We propose the system of a standard procedure and method for HRA to be developed

  13. Systems reliability analysis: applications of the SPARCS System-Reliability Assessment Computer Program

    International Nuclear Information System (INIS)

    Locks, M.O.

    1978-01-01

    SPARCS-2 (Simulation Program for Assessing the Reliabilities of Complex Systems, Version 2) is a PL/1 computer program for assessing (establishing interval estimates for) the reliability and the MTBF of a large and complex s-coherent system of any modular configuration. The system can consist of a complex logical assembly of independently failing attribute (binomial-Bernoulli) and time-to-failure (Poisson-exponential) components, without regard to their placement. Alternatively, it can be a configuration of independently failing modules, where each module has either or both attribute and time-to-failure components. SPARCS-2 also has an improved super modularity feature. Modules with minimal-cut unreliabiliy calculations can be mixed with those having minimal-path reliability calculations. All output has been standardized to system reliability or probability of success, regardless of the form in which the input data is presented, and whatever the configuration of modules or elements within modules

  14. Dependability analysis of proposed I and C architecture for safety systems of a large PWR

    International Nuclear Information System (INIS)

    Kabra, Ashutosh; Karmakar, G.; Tiwari, A.P.; Manoj Kumar; Marathe, P.P.

    2014-01-01

    Instrumentation and Control (I and C) systems in a reactor provide protection against unsafe operation during steady-state and transient power operations. Indian reactors traditionally adopted 2-out-of-3 (2oo3) architecture for safety systems. But, contemporary reactor safety systems are employing 2-out-of-4 (2oo4) architecture in spite of the increased cost due to the additional channel. This motivated us to carry out a comparative study of 2oo3 and 2oo4 architecture, especially for their dependability attributes - safety and availability. Quantitative estimation of safety and availability has been used to adjudge the worthiness of adopting 2oo4 architecture in I and C safety systems of a large PWR. Our analysis using Markov model shows that 2oo4 architecture, even with lower diagnostic coverage and longer proof test interval, can provide better safety and availability in comparison of 2oo3 architecture. This reduces total life cycle cost of system during development phase and complexity and frequency of surveillance test during operational phase. The paper also describes the proposed architecture for Reactor Protection System (RPS), a representative safety system, and determines its dependability using Markov analysis and Failure Mode Effect Analysis (FMEA). The proposed I and C safety system architecture also has been qualitatively analyzed for their effectiveness against common cause failures (CCFs). (author)

  15. Reliability and availability requirements analysis for DEMO: fuel cycle system

    International Nuclear Information System (INIS)

    Pinna, T.; Borgognoni, F.

    2015-01-01

    The Demonstration Power Plant (DEMO) will be a fusion reactor prototype designed to demonstrate the capability to produce electrical power in a commercially acceptable way. Two of the key elements of the engineering development of the DEMO reactor are the definitions of reliability and availability requirements (or targets). The availability target for a hypothesized Fuel Cycle has been analysed as a test case. The analysis has been done on the basis of the experience gained in operating existing tokamak fusion reactors and developing the ITER design. Plant Breakdown Structure (PBS) and Functional Breakdown Structure (FBS) related to the DEMO Fuel Cycle and correlations between PBS and FBS have been identified. At first, a set of availability targets has been allocated to the various systems on the basis of their operating, protection and safety functions. 75% and 85% of availability has been allocated to the operating functions of fuelling system and tritium plant respectively. 99% of availability has been allocated to the overall systems in executing their safety functions. The chances of the systems to achieve the allocated targets have then been investigated through a Failure Mode and Effect Analysis and Reliability Block Diagram analysis. The following results have been obtained: 1) the target of 75% for the operations of the fuelling system looks reasonable, while the target of 85% for the operations of the whole tritium plant should be reduced to 80%, even though all the tritium plant systems can individually reach quite high availability targets, over 90% - 95%; 2) all the DEMO Fuel Cycle systems can reach the target of 99% in accomplishing their safety functions. (authors)

  16. Research on the Reliability Analysis of the Integrated Modular Avionics System Based on the AADL Error Model

    Directory of Open Access Journals (Sweden)

    Peng Wang

    2018-01-01

    Full Text Available In recent years, the integrated modular avionics (IMA concept has been introduced to replace the traditional federated avionics. Different avionics functions are hosted in a shared IMA platform, and IMA adopts partition technologies to provide a logical isolation among different functions. The IMA architecture can provide more sophisticated and powerful avionics functionality; meanwhile, the failure propagation patterns in IMA are more complex. The feature of resource sharing introduces some unintended interconnections among different functions, which makes the failure propagation modes more complex. Therefore, this paper proposes an architecture analysis and design language- (AADL- based method to establish the reliability model of IMA platform. The single software and hardware error behavior in IMA system is modeled. The corresponding AADL error model of failure propagation among components, between software and hardware, is given. Finally, the display function of IMA platform is taken as an example to illustrate the effectiveness of the proposed method.

  17. reliability reliability

    African Journals Online (AJOL)

    eobe

    Corresponding author, Tel: +234-703. RELIABILITY .... V , , given by the code of practice. However, checks must .... an optimization procedure over the failure domain F corresponding .... of Concrete Members based on Utility Theory,. Technical ...

  18. Reliability analysis of large scaled structures by optimization technique

    International Nuclear Information System (INIS)

    Ishikawa, N.; Mihara, T.; Iizuka, M.

    1987-01-01

    This paper presents a reliability analysis based on the optimization technique using PNET (Probabilistic Network Evaluation Technique) method for the highly redundant structures having a large number of collapse modes. This approach makes the best use of the merit of the optimization technique in which the idea of PNET method is used. The analytical process involves the minimization of safety index of the representative mode, subjected to satisfaction of the mechanism condition and of the positive external work. The procedure entails the sequential performance of a series of the NLP (Nonlinear Programming) problems, where the correlation condition as the idea of PNET method pertaining to the representative mode is taken as an additional constraint to the next analysis. Upon succeeding iterations, the final analysis is achieved when a collapse probability at the subsequent mode is extremely less than the value at the 1st mode. The approximate collapse probability of the structure is defined as the sum of the collapse probabilities of the representative modes classified by the extent of correlation. Then, in order to confirm the validity of the proposed method, the conventional Monte Carlo simulation is also revised by using the collapse load analysis. Finally, two fairly large structures were analyzed to illustrate the scope and application of the approach. (orig./HP)

  19. Application of human reliability analysis methodology of second generation

    International Nuclear Information System (INIS)

    Ruiz S, T. de J.; Nelson E, P. F.

    2009-10-01

    The human reliability analysis (HRA) is a very important part of probabilistic safety analysis. The main contribution of HRA in nuclear power plants is the identification and characterization of the issues that are brought together for an error occurring in the human tasks that occur under normal operation conditions and those made after abnormal event. Additionally, the analysis of various accidents in history, it was found that the human component has been a contributing factor in the cause. Because of need to understand the forms and probability of human error in the 60 decade begins with the collection of generic data that result in the development of the first generation of HRA methodologies. Subsequently develop methods to include in their models additional performance shaping factors and the interaction between them. So by the 90 mid, comes what is considered the second generation methodologies. Among these is the methodology A Technique for Human Event Analysis (ATHEANA). The application of this method in a generic human failure event, it is interesting because it includes in its modeling commission error, the additional deviations quantification to nominal scenario considered in the accident sequence of probabilistic safety analysis and, for this event the dependency actions evaluation. That is, the generic human failure event was required first independent evaluation of the two related human failure events . So the gathering of the new human error probabilities involves the nominal scenario quantification and cases of significant deviations considered by the potential impact on analyzed human failure events. Like probabilistic safety analysis, with the analysis of the sequences were extracted factors more specific with the highest contribution in the human error probabilities. (Author)

  20. Co3O4 based non-enzymatic glucose sensor with high sensitivity and reliable stability derived from hollow hierarchical architecture

    Science.gov (United States)

    Tian, Liangliang; He, Gege; Cai, Yanhua; Wu, Shenping; Su, Yongyao; Yan, Hengqing; Yang, Cong; Chen, Yanling; Li, Lu

    2018-02-01

    Inspired by kinetics, the design of hollow hierarchical electrocatalysts through large-scale integration of building blocks is recognized as an effective approach to the achievement of superior electrocatalytic performance. In this work, a hollow, hierarchical Co3O4 architecture (Co3O4 HHA) was constructed using a coordinated etching and precipitation (CEP) method followed by calcination. The resulting Co3O4 HHA electrode exhibited excellent electrocatalytic activity in terms of high sensitivity (839.3 μA mM-1 cm-2) and reliable stability in glucose detection. The high sensitivity could be attributed to the large specific surface area (SSA), ample unimpeded penetration diffusion paths and high electron transfer rate originating from the unique two-dimensional (2D) sheet-like character and hollow porous architecture. The hollow hierarchical structure also affords sufficient interspace for accommodation of volume change and structural strain, resulting in enhanced stability. The results indicate that Co3O4 HHA could have potential for application in the design of non-enzymatic glucose sensors, and that the construction of hollow hierarchical architecture provides an efficient way to design highly active, stable electrocatalysts.

  1. Analogical reasoning for reliability analysis based on generic data

    Energy Technology Data Exchange (ETDEWEB)

    Kozin, Igor O

    1996-10-01

    The paper suggests using the systemic concept 'analogy' for the foundation of an approach to analyze system reliability on the basis of generic data, describing the method of structuring the set that defines analogical models, an approach of transition from the analogical model to a reliability model and a way of obtaining reliability intervals of analogous objects.

  2. Analogical reasoning for reliability analysis based on generic data

    International Nuclear Information System (INIS)

    Kozin, Igor O.

    1996-01-01

    The paper suggests using the systemic concept 'analogy' for the foundation of an approach to analyze system reliability on the basis of generic data, describing the method of structuring the set that defines analogical models, an approach of transition from the analogical model to a reliability model and a way of obtaining reliability intervals of analogous objects

  3. Improvements to Integrated Tradespace Analysis of Communications Architectures (ITACA) Network Loading Analysis Tool

    Science.gov (United States)

    Lee, Nathaniel; Welch, Bryan W.

    2018-01-01

    NASA's SCENIC project aims to simplify and reduce the cost of space mission planning by replicating the analysis capabilities of commercially licensed software which are integrated with relevant analysis parameters specific to SCaN assets and SCaN supported user missions. SCENIC differs from current tools that perform similar analyses in that it 1) does not require any licensing fees, 2) will provide an all-in-one package for various analysis capabilities that normally requires add-ons or multiple tools to complete. As part of SCENIC's capabilities, the ITACA network loading analysis tool will be responsible for assessing the loading on a given network architecture and generating a network service schedule. ITACA will allow users to evaluate the quality of service of a given network architecture and determine whether or not the architecture will satisfy the mission's requirements. ITACA is currently under development, and the following improvements were made during the fall of 2017: optimization of runtime, augmentation of network asset pre-service configuration time, augmentation of Brent's method of root finding, augmentation of network asset FOV restrictions, augmentation of mission lifetimes, and the integration of a SCaN link budget calculation tool. The improvements resulted in (a) 25% reduction in runtime, (b) more accurate contact window predictions when compared to STK(Registered Trademark) contact window predictions, and (c) increased fidelity through the use of specific SCaN asset parameters.

  4. Applicability of simplified human reliability analysis methods for severe accidents

    Energy Technology Data Exchange (ETDEWEB)

    Boring, R.; St Germain, S. [Idaho National Lab., Idaho Falls, Idaho (United States); Banaseanu, G.; Chatri, H.; Akl, Y. [Canadian Nuclear Safety Commission, Ottawa, Ontario (Canada)

    2016-03-15

    Most contemporary human reliability analysis (HRA) methods were created to analyse design-basis accidents at nuclear power plants. As part of a comprehensive expansion of risk assessments at many plants internationally, HRAs will begin considering severe accident scenarios. Severe accidents, while extremely rare, constitute high consequence events that significantly challenge successful operations and recovery. Challenges during severe accidents include degraded and hazardous operating conditions at the plant, the shift in control from the main control room to the technical support center, the unavailability of plant instrumentation, and the need to use different types of operating procedures. Such shifts in operations may also test key assumptions in existing HRA methods. This paper discusses key differences between design basis and severe accidents, reviews efforts to date to create customized HRA methods suitable for severe accidents, and recommends practices for adapting existing HRA methods that are already being used for HRAs at the plants. (author)

  5. Fatigue Reliability Analysis of Wind Turbine Cast Components

    DEFF Research Database (Denmark)

    Rafsanjani, Hesam Mirzaei; Sørensen, John Dalsgaard; Fæster, Søren

    2017-01-01

    .) and to quantify the relevant uncertainties using available fatigue tests. Illustrative results are presented as obtained by statistical analysis of a large set of fatigue data for casted test components typically used for wind turbines. Furthermore, the SN curves (fatigue life curves based on applied stress......The fatigue life of wind turbine cast components, such as the main shaft in a drivetrain, is generally determined by defects from the casting process. These defects may reduce the fatigue life and they are generally distributed randomly in components. The foundries, cutting facilities and test...... facilities can affect the verification of properties by testing. Hence, it is important to have a tool to identify which foundry, cutting and/or test facility produces components which, based on the relevant uncertainties, have the largest expected fatigue life or, alternatively, have the largest reliability...

  6. Basic aspects of stochastic reliability analysis for redundancy systems

    International Nuclear Information System (INIS)

    Doerre, P.

    1989-01-01

    Much confusion has been created by trying to establish common cause failure (CCF) as an extra phenomenon which has to be treated with extra methods in reliability and data analysis. This paper takes another approach which can be roughly described by the statement that dependent failure is the basic phenomenon, while 'independent failure' refers to a special limiting case, namely the perfectly homogeneous population. This approach is motivated by examples demonstrating that common causes do not lead to dependent failure, so far as physical dependencies like shared components are excluded, and that stochastic dependencies are not related to common causes. The possibility to select more than one failure behaviour from an inhomogeneous population is identified as an additional random process which creates stochastic dependence. However, this source of randomness is usually treated in the deterministic limit, which destroys dependence and hence yields incorrect multiple failure frequencies for redundancy structures, thus creating the need for applying corrective CCF models. (author)

  7. An Application of Graph Theory in Markov Chains Reliability Analysis

    Directory of Open Access Journals (Sweden)

    Pavel Skalny

    2014-01-01

    Full Text Available The paper presents reliability analysis which was realized for an industrial company. The aim of the paper is to present the usage of discrete time Markov chains and the flow in network approach. Discrete Markov chains a well-known method of stochastic modelling describes the issue. The method is suitable for many systems occurring in practice where we can easily distinguish various amount of states. Markov chains are used to describe transitions between the states of the process. The industrial process is described as a graph network. The maximal flow in the network corresponds to the production. The Ford-Fulkerson algorithm is used to quantify the production for each state. The combination of both methods are utilized to quantify the expected value of the amount of manufactured products for the given time period.

  8. Time-dependent reliability analysis and condition assessment of structures

    International Nuclear Information System (INIS)

    Ellingwood, B.R.

    1997-01-01

    Structures generally play a passive role in assurance of safety in nuclear plant operation, but are important if the plant is to withstand the effect of extreme environmental or abnormal events. Relative to mechanical and electrical components, structural systems and components would be difficult and costly to replace. While the performance of steel or reinforced concrete structures in service generally has been very good, their strengths may deteriorate during an extended service life as a result of changes brought on by an aggressive environment, excessive loading, or accidental loading. Quantitative tools for condition assessment of aging structures can be developed using time-dependent structural reliability analysis methods. Such methods provide a framework for addressing the uncertainties attendant to aging in the decision process

  9. Reliability analysis for the quench detection in the LHC machine

    CERN Document Server

    Denz, R; Vergara-Fernández, A

    2002-01-01

    The Large Hadron Collider (LHC) will incorporate a large amount of superconducting elements that require protection in case of a quench. Key elements in the quench protection system are the electronic quench detectors. Their reliability will have an important impact on the down time as well as on the operational cost of the collider. The expected rates of both false and missed quenches have been computed for several redundant detection schemes. The developed model takes account of the maintainability of the system to optimise the frequency of foreseen checks, and evaluate their influence on the performance of different detection topologies. Seen the uncertainty of the failure rate of the components combined with the LHC tunnel environment, the study has been completed with a sensitivity analysis of the results. The chosen detection scheme and the maintainability strategy for each detector family are given.

  10. 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.

  11. A reliability analysis of the revised competitiveness index.

    Science.gov (United States)

    Harris, Paul B; Houston, John M

    2010-06-01

    This study examined the reliability of the Revised Competitiveness Index by investigating the test-retest reliability, interitem reliability, and factor structure of the measure based on a sample of 280 undergraduates (200 women, 80 men) ranging in age from 18 to 28 years (M = 20.1, SD = 2.1). The findings indicate that the Revised Competitiveness Index has high test-retest reliability, high inter-item reliability, and a stable factor structure. The results support the assertion that the Revised Competitiveness Index assesses competitiveness as a stable trait rather than a dynamic state.

  12. Area analysis of interconnection networks implemented on the honeycomb architecture

    Energy Technology Data Exchange (ETDEWEB)

    Milutinovic, D

    1996-12-31

    The are utilization of interconnection networks for parallel processing on one form of uniform parallel architecture of cellular type is analyzed. Formulae for the number of cells necessity to realize a networks and the efficiency factor of the system are derived. 15 refs.

  13. Enterprise Architecture-Based Risk and Security Modelling and Analysis

    NARCIS (Netherlands)

    Jonkers, Henk; Quartel, Dick; Kordy, Barbara; Ekstedt, Mathias; Seong Kim, Deng

    2016-01-01

    The growing complexity of organizations and the increasing number of sophisticated cyber attacks asks for a systematic and integral approach to Enterprise Risk and Security Management (ERSM). As enterprise architecture offers the necessary integral perspective, including the business and IT aspects

  14. Quantitative Architectural Analysis: A New Approach to Cortical Mapping

    Science.gov (United States)

    Schleicher, Axel; Morosan, Patricia; Amunts, Katrin; Zilles, Karl

    2009-01-01

    Results from functional imaging studies are often still interpreted using the classical architectonic brain maps of Brodmann and his successors. One obvious weakness in traditional, architectural mapping is the subjective nature of localizing borders between cortical areas by means of a purely visual, microscopical examination of histological…

  15. Dynamic Analysis Techniques for the Reconstruction of Architectural Views

    NARCIS (Netherlands)

    Cornelissen, B.

    2007-01-01

    Gaining an understanding of software systems is an important discipline in many software engineering contexts. It is essential that software engineers are assisted as much as possible during this task, e.g., by using tools and techniques that provide architectural views on the software at hand. This

  16. Development of the integrated system reliability analysis code MODULE

    International Nuclear Information System (INIS)

    Han, S.H.; Yoo, K.J.; Kim, T.W.

    1987-01-01

    The major components in a system reliability analysis are the determination of cut sets, importance measure, and uncertainty analysis. Various computer codes have been used for these purposes. For example, SETS and FTAP are used to determine cut sets; Importance for importance calculations; and Sample, CONINT, and MOCUP for uncertainty analysis. There have been problems when the codes run each other and the input and output are not linked, which could result in errors when preparing input for each code. The code MODULE was developed to carry out the above calculations simultaneously without linking input and outputs to other codes. MODULE can also prepare input for SETS for the case of a large fault tree that cannot be handled by MODULE. The flow diagram of the MODULE code is shown. To verify the MODULE code, two examples are selected and the results and computation times are compared with those of SETS, FTAP, CONINT, and MOCUP on both Cyber 170-875 and IBM PC/AT. Two examples are fault trees of the auxiliary feedwater system (AFWS) of Korea Nuclear Units (KNU)-1 and -2, which have 54 gates and 115 events, 39 gates and 92 events, respectively. The MODULE code has the advantage that it can calculate the cut sets, importances, and uncertainties in a single run with little increase in computing time over other codes and that it can be used in personal computers

  17. Human reliability analysis for advanced control room of KNGR

    International Nuclear Information System (INIS)

    Kim, Myung-Ro; Park, Seong-Kyu

    2000-01-01

    There are two purposes in Human Reliability Analysis (HRA) which was performed during Korean Next Generation Reactor (KNGR) Phase 2 research project. One is to present the human error probability quantification results for Probabilistic Safety Assessment (PSA) and the other is to provide a list of the critical operator actions for Human Factor Engineering (HFE). Critical operator actions were identified from the KNGR HRA/RSA based on selection criteria and incorporated in the MMI Task Analysis, where they receive additional treatment. The use of HRA/PSA results in design, procedure development, and training was ensured by their incorporation in the MMI task analysis and MCR design such as fixed position alarms, displays and controls. Any dominant PSA sequence that takes credit for human performance to achieve acceptable results was incorporated in MMIS validation activities through the PSA-based critical operator actions. The integration of KNGR HRA into MMI design was sufficiently addressed all applicable review criteria of NUREG-0800, Chapter 18, Section 2 F and NUREG-0711. (S.Y.)

  18. Models and data requirements for human reliability analysis

    International Nuclear Information System (INIS)

    1989-03-01

    It has been widely recognised for many years that the safety of the nuclear power generation depends heavily on the human factors related to plant operation. This has been confirmed by the accidents at Three Mile Island and Chernobyl. Both these cases revealed how human actions can defeat engineered safeguards and the need for special operator training to cover the possibility of unexpected plant conditions. The importance of the human factor also stands out in the analysis of abnormal events and insights from probabilistic safety assessments (PSA's), which reveal a large proportion of cases having their origin in faulty operator performance. A consultants' meeting, organized jointly by the International Atomic Energy Agency (IAEA) and the International Institute for Applied Systems Analysis (IIASA) was held at IIASA in Laxenburg, Austria, December 7-11, 1987, with the aim of reviewing existing models used in Probabilistic Safety Assessment (PSA) for Human Reliability Analysis (HRA) and of identifying the data required. The report collects both the contributions offered by the members of the Expert Task Force and the findings of the extensive discussions that took place during the meeting. Refs, figs and tabs

  19. Analysis of Parallel Burn Without Crossfeed TSTO RLV Architectures and Comparison to Parallel Burn With Crossfeed and Series Burn Architectures

    Science.gov (United States)

    Smith, Garrett; Phillips, Alan

    2002-01-01

    There are currently three dominant TSTO class architectures. These are Series Burn (SB), Parallel Burn with crossfeed (PBw/cf), and Parallel Burn without crossfeed (PBncf). The goal of this study was to determine what factors uniquely affect PBncf architectures, how each of these factors interact, and to determine from a performance perspective whether a PBncf vehicle could be competitive with a PBw/cf or SB vehicle using equivalent technology and assumptions. In all cases, performance was evaluated on a relative basis for a fixed payload and mission by comparing gross and dry vehicle masses of a closed vehicle. Propellant combinations studied were LOX: LH2 propelled orbiter and booster (HH) and LOX: Kerosene booster with LOX: LH2 orbiter (KH). The study conclusions were: 1) a PBncf orbiter should be throttled as deeply as possible after launch until the staging point. 2) a detailed structural model is essential to accurate architecture analysis and evaluation. 3) a PBncf TSTO architecture is feasible for systems that stage at mach 7. 3a) HH architectures can achieve a mass growth relative to PBw/cf of ratio and to the position of the orbiter required to align the nozzle heights at liftoff. 5 ) thrust to weight ratios of 1.3 at liftoff and between 1.0 and 0.9 when staging at mach 7 appear to be close to ideal for PBncf vehicles. 6) performance for all vehicles studied is better when staged at mach 7 instead of mach 5. The study showed that a Series Burn architecture has the lowest gross mass for HH cases, and has the lowest dry mass for KH cases. The potential disadvantages of SB are the required use of an air-start for the orbiter engines and potential CG control issues. A Parallel Burn with crossfeed architecture solves both these problems, but the mechanics of a large bipropellant crossfeed system pose significant technical difficulties. Parallel Burn without crossfeed vehicles start both booster and orbiter engines on the ground and thus avoid both the risk of

  20. CALS Baseline Architecture Analysis of Weapons System. Technical Information: Army, Draft. Volume 8

    Science.gov (United States)

    1989-09-01

    This effort was performed to provide a common framework for analysis and planning of CALS initiatives across the military services, leading eventually to the development of a common DoD-wide architecture for CALS. This study addresses Army technical ...

  1. Reliability analysis of component of affination centrifugal 1 machine by using reliability engineering

    Science.gov (United States)

    Sembiring, N.; Ginting, E.; Darnello, T.

    2017-12-01

    Problems that appear in a company that produces refined sugar, the production floor has not reached the level of critical machine availability because it often suffered damage (breakdown). This results in a sudden loss of production time and production opportunities. This problem can be solved by Reliability Engineering method where the statistical approach to historical damage data is performed to see the pattern of the distribution. The method can provide a value of reliability, rate of damage, and availability level, of an machine during the maintenance time interval schedule. The result of distribution test to time inter-damage data (MTTF) flexible hose component is lognormal distribution while component of teflon cone lifthing is weibull distribution. While from distribution test to mean time of improvement (MTTR) flexible hose component is exponential distribution while component of teflon cone lifthing is weibull distribution. The actual results of the flexible hose component on the replacement schedule per 720 hours obtained reliability of 0.2451 and availability 0.9960. While on the critical components of teflon cone lifthing actual on the replacement schedule per 1944 hours obtained reliability of 0.4083 and availability 0.9927.

  2. 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.

  3. Transcriptomic Analysis Using Olive Varieties and Breeding Progenies Identifies Candidate Genes Involved in Plant Architecture.

    Science.gov (United States)

    González-Plaza, Juan J; Ortiz-Martín, Inmaculada; Muñoz-Mérida, Antonio; García-López, Carmen; Sánchez-Sevilla, José F; Luque, Francisco; Trelles, Oswaldo; Bejarano, Eduardo R; De La Rosa, Raúl; Valpuesta, Victoriano; Beuzón, Carmen R

    2016-01-01

    Plant architecture is a critical trait in fruit crops that can significantly influence yield, pruning, planting density and harvesting. Little is known about how plant architecture is genetically determined in olive, were most of the existing varieties are traditional with an architecture poorly suited for modern growing and harvesting systems. In the present study, we have carried out microarray analysis of meristematic tissue to compare expression profiles of olive varieties displaying differences in architecture, as well as seedlings from their cross pooled on the basis of their sharing architecture-related phenotypes. The microarray used, previously developed by our group has already been applied to identify candidates genes involved in regulating juvenile to adult transition in the shoot apex of seedlings. Varieties with distinct architecture phenotypes and individuals from segregating progenies displaying opposite architecture features were used to link phenotype to expression. Here, we identify 2252 differentially expressed genes (DEGs) associated to differences in plant architecture. Microarray results were validated by quantitative RT-PCR carried out on genes with functional annotation likely related to plant architecture. Twelve of these genes were further analyzed in individual seedlings of the corresponding pool. We also examined Arabidopsis mutants in putative orthologs of these targeted candidate genes, finding altered architecture for most of them. This supports a functional conservation between species and potential biological relevance of the candidate genes identified. This study is the first to identify genes associated to plant architecture in olive, and the results obtained could be of great help in future programs aimed at selecting phenotypes adapted to modern cultivation practices in this species.

  4. Enterprise Architecture Modeling of Core Administrative Systems at KTH : A Modifiability Analysis

    OpenAIRE

    Rosell, Peter

    2012-01-01

    This project presents a case study of modifiability analysis on the Information Systems which are central to the core business processes of Royal Institution of Technology in Stockholm, Sweden by creating, updating and using models. The case study was limited to modifiability regarding only specified Information Systems. The method selected was Enterprise Architecture together with Enterprise Architecture Analysis research results and tools from the Industrial Information and Control Systems ...

  5. Integrating acoustic analysis in the architectural design process using parametric modelling

    DEFF Research Database (Denmark)

    Peters, Brady

    2011-01-01

    This paper discusses how parametric modeling techniques can be used to provide architectural designers with a better understanding of the acoustic performance of their designs and provide acoustic engineers with models that can be analyzed using computational acoustic analysis software. Architects......, acoustic performance can inform the geometry and material logic of the design. In this way, the architectural design and the acoustic analysis model become linked....

  6. Software Technology for Adaptable, Reliable Systems (STARS). Software Architecture Seminar Report: Central Archive for Reusable Defense Software (CARDS)

    Science.gov (United States)

    1994-01-29

    for arlistic creatio arindidviduul distinction and recognitio which accoimpanies classical architectur. Architects study design becaus their problems...gi sIk metwflog. wu selecte&W aftd iwd eteniwilon CAIM saft -w~eam mFac Wup eede (BAR). Thu Ocmbi@ Faces (OP) meprelead. an wumoted b88cgrqhy cor...ARIOHfL-M pROVIM A MEIHODOLOGY FOR ADD48NUO AND SOLVING UAY OF THE ISUS FACING SWBMI FOR DEVLOPING A COUPLtXCPI CAPAWLITY S72 1, F i ’ ’ = II IIII

  7. Reliability analysis of land pipelines for hydrocarbons transportation in Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Leon, D.; Cortes, C. [Inst. Mexicano del Petroleo (Mexico)

    2004-07-01

    The reliability of a land pipeline operated by PEMEX in Mexico was estimated under a range of failure modes. Reliability and safety were evaluated in terms of the pipeline's internal pressure, bending, fracture toughness and its tension failure mode conditions. Loading conditions were applied individually, while bending and tension loads were applied in a combined fashion. The mechanical properties of the steel were also considered along with the degradation effect of internal corrosion resulting from the type of product being transported. A set of internal pressures and mechanical properties were generated randomly using Monte Carlo simulation. Commercial software was used to obtain the pipeline response under each modeled condition. The response analysis was based on the nonlinear finite element method involving a calculation of maximum stresses and stress concentration factors under conditions of corrosion and no corrosion. The margin between maximum stresses due to internal pressure, tension and bending was evaluated along with the margin between stress concentration factor and fracture initiation toughness. The study showed that internal pressure, stress concentration and tension-bending were the critical failure modes. It was suggested that more research should be conducted to improve the modeling of the deteriorating effects of corrosion and to adjust the probability distribution for fracture toughness and the length/depth defect ratio. The consideration of welding geometries along with features of marine pipelines and pipeline products would help to generalize the study to facilitate the creation of codes for the construction, design, inspection and maintenance of pipelines in Mexico. 7 refs., 1 tab., 14 figs.

  8. 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.

  9. RELOSS, Reliability of Safety System by Fault Tree Analysis

    International Nuclear Information System (INIS)

    Allan, R.N.; Rondiris, I.L.; Adraktas, A.

    1981-01-01

    1 - Description of problem or function: Program RELOSS is used in the reliability/safety assessment of any complex system with predetermined operational logic in qualitative and (if required) quantitative terms. The program calculates the possible system outcomes following an abnormal operating condition and the probability of occurrence, if required. Furthermore, the program deduces the minimal cut or tie sets of the system outcomes and identifies the potential common mode failures. 4. Method of solution: The reliability analysis performed by the program is based on the event tree methodology. Using this methodology, the program develops the event tree of a system or a module of that system and relates each path of this tree to its qualitative and/or quantitative impact on specified system or module outcomes. If the system being analysed is subdivided into modules the program assesses each module in turn as described previously and then combines the module information to obtain results for the overall system. Having developed the event tree of a module or a system, the program identifies which paths lead or do not lead to various outcomes depending on whether the cut or the tie sets of the outcomes are required and deduces the corresponding sets. Furthermore the program identifies for a specific system outcome, the potential common mode failures and the cut or tie sets containing potential dependent failures of some components. 5. Restrictions on the complexity of the problem: The present dimensions of the program are as follows. They can however be easily modified: Maximum number of modules (equivalent components): 25; Maximum number of components in a module: 15; Maximum number of levels of parentheses in a logical statement: 10 Maximum number of system outcomes: 3; Maximum number of module outcomes: 2; Maximum number of points in time for which quantitative analysis is required: 5; Maximum order of any cut or tie set: 10; Maximum order of a cut or tie of any

  10. The reliability of mercury analysis in environmental materials

    International Nuclear Information System (INIS)

    Heinonen, J.; Suschny, O.

    1973-01-01

    Mercury occurs in nature in its native elemental as well as in different mineral forms. It has been mined for centuries and is used in many branches of industry, agriculture and medicine. Mercury is very toxic to man and reports of poisoning due to the presence of the element in fish and shellfish caught at Minamata and Niigata, Japan have led not only to local investigations but to multi-national research into the sources and the levels of mercury in the environment. The concentrations at which the element has to be determined in these studies are extremely small, usually of the order of a few parts in 10 9 parts of environmental material. Few analytical techniques provide the required sensitivity for analysis at such low concentrations, and only two are normally used for mercury: neutron activation analysis and atomic absorption photometry. They are also the most convenient end points of various separation schemes for different organic mercury compounds. Mercury analysis at the ppb-level is beset with many problems: volatility of the metal and its compounds, impurity of reagents, interference by other elements and many other analytical difficulties may influence the results. To be able to draw valid conclusions from the analyses it is necessary to know the reliability attached to the values obtained. To assist laboratories in the evaluation of their analytical performance, the International Atomic Energy Agency through its own laboratory at Seibersdorf already organised in 1967 an intercomparison of mercury analysis in flour. Based on the results obtained at that time, a whole series of intercomparisons of mercury determinations in nine different environmental materials was undertaken in 1971. The materials investigated included corn and wheat flour, spray-dried animal blood serum, fish solubles, milk powder, saw dust, cellulose, lacquer paint and coloric material

  11. The reliability of mercury analysis in environmental materials

    Energy Technology Data Exchange (ETDEWEB)

    Heinonen, J.; Suschny, O

    1973-01-01

    Mercury occurs in nature in its native elemental as well as in different mineral forms. It has been mined for centuries and is used in many branches of industry, agriculture and medicine. Mercury is very toxic to man and reports of poisoning due to the presence of the element in fish and shellfish caught at Minamata and Niigata, Japan have led not only to local investigations but to multi-national research into the sources and the levels of mercury in the environment. The concentrations at which the element has to be determined in these studies are extremely small, usually of the order of a few parts in 10{sup 9} parts of environmental material. Few analytical techniques provide the required sensitivity for analysis at such low concentrations, and only two are normally used for mercury: neutron activation analysis and atomic absorption photometry. They are also the most convenient end points of various separation schemes for different organic mercury compounds. Mercury analysis at the ppb-level is beset with many problems: volatility of the metal and its compounds, impurity of reagents, interference by other elements and many other analytical difficulties may influence the results. To be able to draw valid conclusions from the analyses it is necessary to know the reliability attached to the values obtained. To assist laboratories in the evaluation of their analytical performance, the International Atomic Energy Agency through its own laboratory at Seibersdorf already organised in 1967 an intercomparison of mercury analysis in flour. Based on the results obtained at that time, a whole series of intercomparisons of mercury determinations in nine different environmental materials was undertaken in 1971. The materials investigated included corn and wheat flour, spray-dried animal blood serum, fish solubles, milk powder, saw dust, cellulose, lacquer paint and coloric material.

  12. Multi-Unit Considerations for Human Reliability Analysis

    Energy Technology Data Exchange (ETDEWEB)

    St. Germain, S.; Boring, R.; Banaseanu, G.; Akl, Y.; Chatri, H.

    2017-03-01

    This paper uses the insights from the Standardized Plant Analysis Risk-Human Reliability Analysis (SPAR-H) methodology to help identify human actions currently modeled in the single unit PSA that may need to be modified to account for additional challenges imposed by a multi-unit accident as well as identify possible new human actions that might be modeled to more accurately characterize multi-unit risk. In identifying these potential human action impacts, the use of the SPAR-H strategy to include both errors in diagnosis and errors in action is considered as well as identifying characteristics of a multi-unit accident scenario that may impact the selection of the performance shaping factors (PSFs) used in SPAR-H. The lessons learned from the Fukushima Daiichi reactor accident will be addressed to further help identify areas where improved modeling may be required. While these multi-unit impacts may require modifications to a Level 1 PSA model, it is expected to have much more importance for Level 2 modeling. There is little currently written specifically about multi-unit HRA issues. A review of related published research will be presented. While this paper cannot answer all issues related to multi-unit HRA, it will hopefully serve as a starting point to generate discussion and spark additional ideas towards the proper treatment of HRA in a multi-unit PSA.

  13. 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...

  14. Field Programmable Gate Array Reliability Analysis Guidelines for Launch Vehicle Reliability Block Diagrams

    Science.gov (United States)

    Al Hassan, Mohammad; Britton, Paul; Hatfield, Glen Spencer; Novack, Steven D.

    2017-01-01

    Field Programmable Gate Arrays (FPGAs) integrated circuits (IC) are one of the key electronic components in today's sophisticated launch and space vehicle complex avionic systems, largely due to their superb reprogrammable and reconfigurable capabilities combined with relatively low non-recurring engineering costs (NRE) and short design cycle. Consequently, FPGAs are prevalent ICs in communication protocols and control signal commands. This paper will identify reliability concerns and high level guidelines to estimate FPGA total failure rates in a launch vehicle application. The paper will discuss hardware, hardware description language, and radiation induced failures. The hardware contribution of the approach accounts for physical failures of the IC. The hardware description language portion will discuss the high level FPGA programming languages and software/code reliability growth. The radiation portion will discuss FPGA susceptibility to space environment radiation.

  15. The reliability analysis of cutting tools in the HSM processes

    OpenAIRE

    W.S. Lin

    2008-01-01

    Purpose: This article mainly describe the reliability of the cutting tools in the high speed turning by normaldistribution model.Design/methodology/approach: A series of experimental tests have been done to evaluate the reliabilityvariation of the cutting tools. From experimental results, the tool wear distribution and the tool life are determined,and the tool life distribution and the reliability function of cutting tools are derived. Further, the reliability ofcutting tools at anytime for h...

  16. 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)

  17. 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)

  18. Science Based Human Reliability Analysis: Using Digital Nuclear Power Plant Simulators for Human Reliability Research

    Science.gov (United States)

    Shirley, Rachel Elizabeth

    Nuclear power plant (NPP) simulators are proliferating in academic research institutions and national laboratories in response to the availability of affordable, digital simulator platforms. Accompanying the new research facilities is a renewed interest in using data collected in NPP simulators for Human Reliability Analysis (HRA) research. An experiment conducted in The Ohio State University (OSU) NPP Simulator Facility develops data collection methods and analytical tools to improve use of simulator data in HRA. In the pilot experiment, student operators respond to design basis accidents in the OSU NPP Simulator Facility. Thirty-three undergraduate and graduate engineering students participated in the research. Following each accident scenario, student operators completed a survey about perceived simulator biases and watched a video of the scenario. During the video, they periodically recorded their perceived strength of significant Performance Shaping Factors (PSFs) such as Stress. This dissertation reviews three aspects of simulator-based research using the data collected in the OSU NPP Simulator Facility: First, a qualitative comparison of student operator performance to computer simulations of expected operator performance generated by the Information Decision Action Crew (IDAC) HRA method. Areas of comparison include procedure steps, timing of operator actions, and PSFs. Second, development of a quantitative model of the simulator bias introduced by the simulator environment. Two types of bias are defined: Environmental Bias and Motivational Bias. This research examines Motivational Bias--that is, the effect of the simulator environment on an operator's motivations, goals, and priorities. A bias causal map is introduced to model motivational bias interactions in the OSU experiment. Data collected in the OSU NPP Simulator Facility are analyzed using Structural Equation Modeling (SEM). Data include crew characteristics, operator surveys, and time to recognize

  19. Docker container analysis and application in microservice architecture

    OpenAIRE

    Benedik, Dejan

    2016-01-01

    Using container technology to run web applications and services is becoming increasingly common [9]. In this work we analyse the most popular container technology, Docker, and compare it with other Linux-based container technologies. Due to near-instant startup and minimal overhead, containers are facilitating a new way of designing software applications that is called microservice architecture. We analyse the approach and compare it with its alternatives. We examine some aspects of running s...

  20. Reliability and risk analysis data base development: an historical perspective

    International Nuclear Information System (INIS)

    Fragola, Joseph R.

    1996-01-01

    Collection of empirical data and data base development for use in the prediction of the probability of future events has a long history. Dating back at least to the 17th century, safe passage events and mortality events were collected and analyzed to uncover prospective underlying classes and associated class attributes. Tabulations of these developed classes and associated attributes formed the underwriting basis for the fledgling insurance industry. Much earlier, master masons and architects used design rules of thumb to capture the experience of the ages and thereby produce structures of incredible longevity and reliability (Antona, E., Fragola, J. and Galvagni, R. Risk based decision analysis in design. Fourth SRA Europe Conference Proceedings, Rome, Italy, 18-20 October 1993). These rules served so well in producing robust designs that it was not until almost the 19th century that the analysis (Charlton, T.M., A History Of Theory Of Structures In The 19th Century, Cambridge University Press, Cambridge, UK, 1982) of masonry voussoir arches, begun by Galileo some two centuries earlier (Galilei, G. Discorsi e dimostrazioni mathematiche intorno a due nuove science, (Discourses and mathematical demonstrations concerning two new sciences, Leiden, The Netherlands, 1638), was placed on a sound scientific basis. Still, with the introduction of new materials (such as wrought iron and steel) and the lack of theoretical knowledge and computational facilities, approximate methods of structural design abounded well into the second half of the 20th century. To this day structural designers account for material variations and gaps in theoretical knowledge by employing factors of safety (Benvenuto, E., An Introduction to the History of Structural Mechanics, Part II: Vaulted Structures and Elastic Systems, Springer-Verlag, NY, 1991) or codes of practice (ASME Boiler and Pressure Vessel Code, ASME, New York) originally developed in the 19th century (Antona, E., Fragola, J. and

  1. Performance analysis of IMS based LTE and WIMAX integration architectures

    Directory of Open Access Journals (Sweden)

    A. Bagubali

    2016-12-01

    Full Text Available In the current networking field many research works are going on regarding the integration of different wireless technologies, with the aim of providing uninterrupted connectivity to the user anywhere, with high data rates due to increased demand. However, the number of objects like smart devices, industrial machines, smart homes, connected by wireless interface is dramatically increasing due to the evolution of cloud computing and internet of things technology. This Paper begins with the challenges involved in such integrations and then explains the role of different couplings and different architectures. This paper also gives further improvement in the LTE and Wimax integration architectures to provide seamless vertical handover and flexible quality of service for supporting voice, video, multimedia services over IP network and mobility management with the help of IMS networks. Evaluation of various parameters like handover delay, cost of signalling, packet loss,, is done and the performance of the interworking architecture is analysed from the simulation results. Finally, it concludes that the cross layer scenario is better than the non cross layer scenario.

  2. 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

  3. 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

  4. 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...

  5. Rapid architecture alternative modeling (RAAM): A framework for capability-based analysis of system of systems architectures

    Science.gov (United States)

    Iacobucci, Joseph V.

    The research objective for this manuscript is to develop a Rapid Architecture Alternative Modeling (RAAM) methodology to enable traceable Pre-Milestone A decision making during the conceptual phase of design of a system of systems. Rather than following current trends that place an emphasis on adding more analysis which tends to increase the complexity of the decision making problem, RAAM improves on current methods by reducing both runtime and model creation complexity. RAAM draws upon principles from computer science, system architecting, and domain specific languages to enable the automatic generation and evaluation of architecture alternatives. For example, both mission dependent and mission independent metrics are considered. Mission dependent metrics are determined by the performance of systems accomplishing a task, such as Probability of Success. In contrast, mission independent metrics, such as acquisition cost, are solely determined and influenced by the other systems in the portfolio. RAAM also leverages advances in parallel computing to significantly reduce runtime by defining executable models that are readily amendable to parallelization. This allows the use of cloud computing infrastructures such as Amazon's Elastic Compute Cloud and the PASTEC cluster operated by the Georgia Institute of Technology Research Institute (GTRI). Also, the amount of data that can be generated when fully exploring the design space can quickly exceed the typical capacity of computational resources at the analyst's disposal. To counter this, specific algorithms and techniques are employed. Streaming algorithms and recursive architecture alternative evaluation algorithms are used that reduce computer memory requirements. Lastly, a domain specific language is created to provide a reduction in the computational time of executing the system of systems models. A domain specific language is a small, usually declarative language that offers expressive power focused on a particular

  6. 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

  7. 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)

  8. Operator reliability analysis during NPP small break LOCA

    International Nuclear Information System (INIS)

    Zhang Jiong; Chen Shenglin

    1990-01-01

    To assess the human factor characteristic of a NPP main control room (MCR) design, the MCR operator reliability during a small break LOCA is analyzed, and some approaches for improving the MCR operator reliability are proposed based on the analyzing results

  9. An ODMG-compatible testbed architecture for scalable management and analysis of physics data

    International Nuclear Information System (INIS)

    Malon, D.M.; May, E.N.

    1997-01-01

    This paper describes a testbed architecture for the investigation and development of scalable approaches to the management and analysis of massive amounts of high energy physics data. The architecture has two components: an interface layer that is compliant with a substantial subset of the ODMG-93 Version 1.2 specification, and a lightweight object persistence manager that provides flexible storage and retrieval services on a variety of single- and multi-level storage architectures, and on a range of parallel and distributed computing platforms

  10. Wind turbine reliability : a database and analysis approach.

    Energy Technology Data Exchange (ETDEWEB)

    Linsday, James (ARES Corporation); Briand, Daniel; Hill, Roger Ray; Stinebaugh, Jennifer A.; Benjamin, Allan S. (ARES Corporation)

    2008-02-01

    The US wind Industry has experienced remarkable growth since the turn of the century. At the same time, the physical size and electrical generation capabilities of wind turbines has also experienced remarkable growth. As the market continues to expand, and as wind generation continues to gain a significant share of the generation portfolio, the reliability of wind turbine technology becomes increasingly important. This report addresses how operations and maintenance costs are related to unreliability - that is the failures experienced by systems and components. Reliability tools are demonstrated, data needed to understand and catalog failure events is described, and practical wind turbine reliability models are illustrated, including preliminary results. This report also presents a continuing process of how to proceed with controlling industry requirements, needs, and expectations related to Reliability, Availability, Maintainability, and Safety. A simply stated goal of this process is to better understand and to improve the operable reliability of wind turbine installations.

  11. The effect of loss functions on empirical Bayes reliability analysis

    Directory of Open Access Journals (Sweden)

    Camara Vincent A. R.

    1998-01-01

    Full Text Available The aim of the present study is to investigate the sensitivity of empirical Bayes estimates of the reliability function with respect to changing of the loss function. In addition to applying some of the basic analytical results on empirical Bayes reliability obtained with the use of the “popular” squared error loss function, we shall derive some expressions corresponding to empirical Bayes reliability estimates obtained with the Higgins–Tsokos, the Harris and our proposed logarithmic loss functions. The concept of efficiency, along with the notion of integrated mean square error, will be used as a criterion to numerically compare our results. It is shown that empirical Bayes reliability functions are in general sensitive to the choice of the loss function, and that the squared error loss does not always yield the best empirical Bayes reliability estimate.

  12. Reliability analysis of water distribution systems under uncertainty

    International Nuclear Information System (INIS)

    Kansal, M.L.; Kumar, Arun; Sharma, P.B.

    1995-01-01

    In most of the developing countries, the Water Distribution Networks (WDN) are of intermittent type because of the shortage of safe drinking water. Failure of a pipeline(s) in such cases will cause not only the fall in one or more nodal heads but also the poor connectivity of source with various demand nodes of the system. Most of the previous works have used the two-step algorithm based on pathset or cutset approach for connectivity analysis. The computations become more cumbersome when connectivity of all demand nodes taken together with that of supply is carried out. In the present paper, network connectivity based on the concept of Appended Spanning Tree (AST) is suggested to compute global network connectivity which is defined as the probability of the source node being connected with all the demand nodes simultaneously. The concept of AST has distinct advantages as it attacks the problem directly rather than in an indirect way as most of the studies so far have done. Since the water distribution system is a repairable one, a general expression for pipeline avialability using the failure/repair rate is considered. Furthermore, the sensitivity of global reliability estimates due to the likely error in the estimation of failure/repair rates of various pipelines is also studied

  13. CRITICAL ANALYSIS OF THE RELIABILITY OF INTUITIVE MORAL DECISIONS

    Directory of Open Access Journals (Sweden)

    V. V. Nadurak

    2017-06-01

    Full Text Available Purpose of the research is a critical analysis of the reliability of intuitive moral decisions. Methodology. The work is based on the methodological attitude of empirical ethics, involving the use of findings from empirical research in ethical reflection and decision making. Originality. The main kinds of intuitive moral decisions are identified: 1 intuitively emotional decisions (i.e. decisions made under the influence of emotions that accompanies the process of moral decision making; 2 decisions made under the influence of moral risky psychological aptitudes (unconscious human tendencies that makes us think in a certain way and make decisions, unacceptable from the logical and ethical point of view; 3 intuitively normative decisions (decisions made under the influence of socially learned norms, that cause evaluative feeling «good-bad», without conscious reasoning. It was found that all of these kinds of intuitive moral decisions can lead to mistakes in the moral life. Conclusions. Considering the fact that intuition systematically leads to erroneous moral decisions, intuitive reaction cannot be the only source for making such decisions. The conscious rational reasoning can compensate for weaknesses of intuition. In this case, there is a necessity in theoretical model that would structure the knowledge about the interactions between intuitive and rational factors in moral decisions making and became the basis for making suggestions that would help us to make the right moral decision.

  14. Monte Carlo methods for the reliability analysis of Markov systems

    International Nuclear Information System (INIS)

    Buslik, A.J.

    1985-01-01

    This paper presents Monte Carlo methods for the reliability analysis of Markov systems. Markov models are useful in treating dependencies between components. The present paper shows how the adjoint Monte Carlo method for the continuous time Markov process can be derived from the method for the discrete-time Markov process by a limiting process. The straightforward extensions to the treatment of mean unavailability (over a time interval) are given. System unavailabilities can also be estimated; this is done by making the system failed states absorbing, and not permitting repair from them. A forward Monte Carlo method is presented in which the weighting functions are related to the adjoint function. In particular, if the exact adjoint function is known then weighting factors can be constructed such that the exact answer can be obtained with a single Monte Carlo trial. Of course, if the exact adjoint function is known, there is no need to perform the Monte Carlo calculation. However, the formulation is useful since it gives insight into choices of the weight factors which will reduce the variance of the estimator

  15. Reliability analysis of load-sharing systems with memory.

    Science.gov (United States)

    Wang, Dewei; Jiang, Chendi; Park, Chanseok

    2018-02-22

    The load-sharing model has been studied since the early 1940s to account for the stochastic dependence of components in a parallel system. It assumes that, as components fail one by one, the total workload applied to the system is shared by the remaining components and thus affects their performance. Such dependent systems have been studied in many engineering applications which include but are not limited to fiber composites, manufacturing, power plants, workload analysis of computing, software and hardware reliability, etc. Many statistical models have been proposed to analyze the impact of each redistribution of the workload; i.e., the changes on the hazard rate of each remaining component. However, they do not consider how long a surviving component has worked for prior to the redistribution. We name such load-sharing models as memoryless. To remedy this potential limitation, we propose a general framework for load-sharing models that account for the work history. Through simulation studies, we show that an inappropriate use of the memoryless assumption could lead to inaccurate inference on the impact of redistribution. Further, a real-data example of plasma display devices is analyzed to illustrate our methods.

  16. Architectural Analysis of Complex Evolving Systems of Systems

    Science.gov (United States)

    Lindvall, Mikael; Stratton, William C.; Sibol, Deane E.; Ray, Arnab; Ackemann, Chris; Yonkwa, Lyly; Ganesan, Dharma

    2009-01-01

    The goal of this collaborative project between FC-MD, APL, and GSFC and supported by NASA IV&V Software Assurance Research Program (SARP), was to develop a tool, Dynamic SAVE, or Dyn-SAVE for short, for analyzing architectures of systems of systems. The project team was comprised of the principal investigator (PI) from FC-MD and four other FC-MD scientists (part time) and several FC-MD students (full time), as well as, two APL software architects (part time), and one NASA POC (part time). The PI and FC-MD scientists together with APL architects were responsible for requirements analysis, and for applying and evaluating the Dyn-SAVE tool and method. The PI and a group of FC-MD scientists were responsible for improving the method and conducting outreach activities, while another group of FC-MD scientists were responsible for development and improvement of the tool. Oversight and reporting was conducted by the PI and NASA POC. The project team produced many results including several prototypes of the Dyn-SAVE tool and method, several case studies documenting how the tool and method was applied to APL s software systems, and several published papers in highly respected conferences and journals. Dyn-SAVE as developed and enhanced throughout this research period, is a software tool intended for software developers and architects, software integration testers, and persons who need to analyze software systems from the point of view of how it communicates with other systems. Using the tool, the user specifies the planned communication behavior of the system modeled as a sequence diagram. The user then captures and imports the actual communication behavior of the system, which is then converted and visualized as a sequence diagram by Dyn-SAVE. After mapping the planned to the actual and specifying parameter and timing constraints, Dyn-SAVE detects and highlights deviations between the planned and the actual behavior. Requirements based on the need to analyze two inter

  17. 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

  18. Value-centric design architecture based on analysis of space system characteristics

    Science.gov (United States)

    Xu, Q.; Hollingsworth, P.; Smith, K.

    2018-03-01

    Emerging design concepts such as miniaturisation, modularity, and standardisation, have contributed to the rapid development of small and inexpensive platforms, particularly cubesats. This has been stimulating an upcoming revolution in space design and development, leading satellites into the era of "smaller, faster, and cheaper". However, the current requirement-centric design philosophy, focused on bespoke monolithic systems, along with the associated development and production process does not inherently fit with the innovative modular, standardised, and mass-produced technologies. This paper presents a new categorisation, characterisation, and value-centric design architecture to address this need for both traditional and novel system designs. Based on the categorisation of system configurations, a characterisation of space systems, comprised of duplication, fractionation, and derivation, is proposed to capture the overall system configuration characteristics and promote potential hybrid designs. Complying with the definitions of the system characterisation, mathematical mapping relations between the system characterisation and the system properties are described to establish the mathematical foundation of the proposed value-centric design methodology. To illustrate the methodology, subsystem reliability relationships are therefore analysed to explore potential system configurations in the design space. The results of the applications of system characteristic analysis clearly show that the effects of different configuration characteristics on the system properties can be effectively analysed and evaluated, enabling the optimization of system configurations.

  19. Spinal appearance questionnaire: factor analysis, scoring, reliability, and validity testing.

    Science.gov (United States)

    Carreon, Leah Y; Sanders, James O; Polly, David W; Sucato, Daniel J; Parent, Stefan; Roy-Beaudry, Marjolaine; Hopkins, Jeffrey; McClung, Anna; Bratcher, Kelly R; Diamond, Beverly E

    2011-08-15

    Cross sectional. This study presents the factor analysis of the Spinal Appearance Questionnaire (SAQ) and its psychometric properties. Although the SAQ has been administered to a large sample of patients with adolescent idiopathic scoliosis (AIS) treated surgically, its psychometric properties have not been fully evaluated. This study presents the factor analysis and scoring of the SAQ and evaluates its psychometric properties. The SAQ and the Scoliosis Research Society-22 (SRS-22) were administered to AIS patients who were being observed, braced or scheduled for surgery. Standard demographic data and radiographic measures including Lenke type and curve magnitude were also collected. Of the 1802 patients, 83% were female; with a mean age of 14.8 years and mean initial Cobb angle of 55.8° (range, 0°-123°). From the 32 items of the SAQ, 15 loaded on two factors with consistent and significant correlations across all Lenke types. There is an Appearance (items 1-10) and an Expectations factor (items 12-15). Responses are summed giving a range of 5 to 50 for the Appearance domain and 5 to 20 for the Expectations domain. The Cronbach's α was 0.88 for both domains and Total score with a test-retest reliability of 0.81 for Appearance and 0.91 for Expectations. Correlations with major curve magnitude were higher for the SAQ Appearance and SAQ Total scores compared to correlations between the SRS Appearance and SRS Total scores. The SAQ and SRS-22 Scores were statistically significantly different in patients who were scheduled for surgery compared to those who were observed or braced. The SAQ is a valid measure of self-image in patients with AIS with greater correlation to curve magnitude than SRS Appearance and Total score. It also discriminates between patients who require surgery from those who do not.

  20. An efficient phased mission reliability analysis for autonomous vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Remenyte-Prescott, R., E-mail: R.Remenyte-Prescott@nottingham.ac.u [Nottingham Transportation Engineering Centre, Faculty of Engineering, University of Nottingham, Nottingham NG7 2RD (United Kingdom); Andrews, J.D. [Nottingham Transportation Engineering Centre, Faculty of Engineering, University of Nottingham, Nottingham NG7 2RD (United Kingdom); Chung, P.W.H. [Department of Computer Science, Loughborough University, Loughborough LE11 3TU (United Kingdom)

    2010-03-15

    Autonomous systems are becoming more commonly used, especially in hazardous situations. Such systems are expected to make their own decisions about future actions when some capabilities degrade due to failures of their subsystems. Such decisions are made without human input, therefore they need to be well-informed in a short time when the situation is analysed and future consequences of the failure are estimated. The future planning of the mission should take account of the likelihood of mission failure. The reliability analysis for autonomous systems can be performed using the methodologies developed for phased mission analysis, where the causes of failure for each phase in the mission can be expressed by fault trees. Unmanned autonomous vehicles (UAVs) are of a particular interest in the aeronautical industry, where it is a long term ambition to operate them routinely in civil airspace. Safety is the main requirement for the UAV operation and the calculation of failure probability of each phase and the overall mission is the topic of this paper. When components or subsystems fail or environmental conditions throughout the mission change, these changes can affect the future mission. The new proposed methodology takes into account the available diagnostics data and is used to predict future capabilities of the UAV in real time. Since this methodology is based on the efficient BDD method, the quickly provided advice can be used in making decisions. When failures occur appropriate actions are required in order to preserve safety of the autonomous vehicle. The overall decision making strategy for autonomous vehicles is explained in this paper. Some limitations of the methodology are discussed and further improvements are presented based on experimental results.

  1. An efficient phased mission reliability analysis for autonomous vehicles

    International Nuclear Information System (INIS)

    Remenyte-Prescott, R.; Andrews, J.D.; Chung, P.W.H.

    2010-01-01

    Autonomous systems are becoming more commonly used, especially in hazardous situations. Such systems are expected to make their own decisions about future actions when some capabilities degrade due to failures of their subsystems. Such decisions are made without human input, therefore they need to be well-informed in a short time when the situation is analysed and future consequences of the failure are estimated. The future planning of the mission should take account of the likelihood of mission failure. The reliability analysis for autonomous systems can be performed using the methodologies developed for phased mission analysis, where the causes of failure for each phase in the mission can be expressed by fault trees. Unmanned autonomous vehicles (UAVs) are of a particular interest in the aeronautical industry, where it is a long term ambition to operate them routinely in civil airspace. Safety is the main requirement for the UAV operation and the calculation of failure probability of each phase and the overall mission is the topic of this paper. When components or subsystems fail or environmental conditions throughout the mission change, these changes can affect the future mission. The new proposed methodology takes into account the available diagnostics data and is used to predict future capabilities of the UAV in real time. Since this methodology is based on the efficient BDD method, the quickly provided advice can be used in making decisions. When failures occur appropriate actions are required in order to preserve safety of the autonomous vehicle. The overall decision making strategy for autonomous vehicles is explained in this paper. Some limitations of the methodology are discussed and further improvements are presented based on experimental results.

  2. A modular microfluidic architecture for integrated biochemical analysis.

    Science.gov (United States)

    Shaikh, Kashan A; Ryu, Kee Suk; Goluch, Edgar D; Nam, Jwa-Min; Liu, Juewen; Thaxton, C Shad; Chiesl, Thomas N; Barron, Annelise E; Lu, Yi; Mirkin, Chad A; Liu, Chang

    2005-07-12

    Microfluidic laboratory-on-a-chip (LOC) systems based on a modular architecture are presented. The architecture is conceptualized on two levels: a single-chip level and a multiple-chip module (MCM) system level. At the individual chip level, a multilayer approach segregates components belonging to two fundamental categories: passive fluidic components (channels and reaction chambers) and active electromechanical control structures (sensors and actuators). This distinction is explicitly made to simplify the development process and minimize cost. Components belonging to these two categories are built separately on different physical layers and can communicate fluidically via cross-layer interconnects. The chip that hosts the electromechanical control structures is called the microfluidic breadboard (FBB). A single LOC module is constructed by attaching a chip comprised of a custom arrangement of fluid routing channels and reactors (passive chip) to the FBB. Many different LOC functions can be achieved by using different passive chips on an FBB with a standard resource configuration. Multiple modules can be interconnected to form a larger LOC system (MCM level). We demonstrated the utility of this architecture by developing systems for two separate biochemical applications: one for detection of protein markers of cancer and another for detection of metal ions. In the first case, free prostate-specific antigen was detected at 500 aM concentration by using a nanoparticle-based bio-bar-code protocol on a parallel MCM system. In the second case, we used a DNAzyme-based biosensor to identify the presence of Pb(2+) (lead) at a sensitivity of 500 nM in <1 nl of solution.

  3. In-Depth Modeling of the UNIX Operating System for Architectural Cyber Security Analysis

    OpenAIRE

    Vernotte, Alexandre; Johnson, Pontus; Ekstedt, Mathias; Lagerström, Robert

    2017-01-01

    ICT systems have become an integral part of business and life. At the same time, these systems have become extremely complex. In such systems exist numerous vulnerabilities waiting to be exploited by potential threat actors. pwnPr3d is a novel modelling approach that performs automated architectural analysis with the objective of measuring the cyber security of the modeled architecture. Its integrated modelling language allows users to model software and hardware components with great level o...

  4. Analysis of central enterprise architecture elements in models of six eHealth projects.

    Science.gov (United States)

    Virkanen, Hannu; Mykkänen, Juha

    2014-01-01

    Large-scale initiatives for eHealth services have been established in many countries on regional or national level. The use of Enterprise Architecture has been suggested as a methodology to govern and support the initiation, specification and implementation of large-scale initiatives including the governance of business changes as well as information technology. This study reports an analysis of six health IT projects in relation to Enterprise Architecture elements, focusing on central EA elements and viewpoints in different projects.

  5. Motion/imagery secure cloud enterprise architecture analysis

    Science.gov (United States)

    DeLay, John L.

    2012-06-01

    Cloud computing with storage virtualization and new service-oriented architectures brings a new perspective to the aspect of a distributed motion imagery and persistent surveillance enterprise. Our existing research is focused mainly on content management, distributed analytics, WAN distributed cloud networking performance issues of cloud based technologies. The potential of leveraging cloud based technologies for hosting motion imagery, imagery and analytics workflows for DOD and security applications is relatively unexplored. This paper will examine technologies for managing, storing, processing and disseminating motion imagery and imagery within a distributed network environment. Finally, we propose areas for future research in the area of distributed cloud content management enterprises.

  6. Evalution of BIM and Ecotect for Conceptual Architectural Design Analysis

    DEFF Research Database (Denmark)

    Thuesen, Niels; Kirkegaard, Poul Henning; Jensen, Rasmus Lund

    2010-01-01

    The main goal of the present paper is to investigate how BIM tools and Ecotect can be integrated as active part of an integrated design process for conceptual architectural design. The integrated design has an interaction between the skills of the architect and the engineer thought-out the process...... and thereby avoiding problems solving after the design has been finalised. The process has been analysed from an architect's point of view dealing with design at fictive sites in Copenhagen. The results of the research indicate that BIM tools combined with Ecotect can deliver useable qualitative input...

  7. Android: Analysis of its architecture and security mechanism

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    As Android operation system platform is widely used in smart phone, one important aspect should not be ignored -its security. As android is an open mobile platform, and also a programmable software framework, is it more safe than his competitor - Iphone, Symbian and so on? This paper will present some security issues on the mobile phones, analyze the security principles and mechanisms based on the architecture and features of Android OS platform, then it will compare Android with some other mobile operation systems like Iphone, Symbian in area of security to make a conclusion that Android is a safe mobile OS to a certain extent.

  8. Distribution-level electricity reliability: Temporal trends using statistical analysis

    International Nuclear Information System (INIS)

    Eto, Joseph H.; LaCommare, Kristina H.; Larsen, Peter; Todd, Annika; Fisher, Emily

    2012-01-01

    This paper helps to address the lack of comprehensive, national-scale information on the reliability of the U.S. electric power system by assessing trends in U.S. electricity reliability based on the information reported by the electric utilities on power interruptions experienced by their customers. The research analyzes up to 10 years of electricity reliability information collected from 155 U.S. electric utilities, which together account for roughly 50% of total U.S. electricity sales. We find that reported annual average duration and annual average frequency of power interruptions have been increasing over time at a rate of approximately 2% annually. We find that, independent of this trend, installation or upgrade of an automated outage management system is correlated with an increase in the reported annual average duration of power interruptions. We also find that reliance on IEEE Standard 1366-2003 is correlated with higher reported reliability compared to reported reliability not using the IEEE standard. However, we caution that we cannot attribute reliance on the IEEE standard as having caused or led to higher reported reliability because we could not separate the effect of reliance on the IEEE standard from other utility-specific factors that may be correlated with reliance on the IEEE standard. - Highlights: ► We assess trends in electricity reliability based on the information reported by the electric utilities. ► We use rigorous statistical techniques to account for utility-specific differences. ► We find modest declines in reliability analyzing interruption duration and frequency experienced by utility customers. ► Installation or upgrade of an OMS is correlated to an increase in reported duration of power interruptions. ► We find reliance in IEEE Standard 1366 is correlated with higher reported reliability.

  9. Modeling cognition dynamics and its application to human reliability analysis

    International Nuclear Information System (INIS)

    Mosleh, A.; Smidts, C.; Shen, S.H.

    1996-01-01

    For the past two decades, a number of approaches have been proposed for the identification and estimation of the likelihood of human errors, particularly for use in the risk and reliability studies of nuclear power plants. Despite the wide-spread use of the most popular among these methods, their fundamental weaknesses are widely recognized, and the treatment of human reliability has been considered as one of the soft spots of risk studies of large technological systems. To alleviate the situation, new efforts have focused on the development of human reliability models based on a more fundamental understanding of operator response and its cognitive aspects

  10. The effect of loss functions on empirical Bayes reliability analysis

    Directory of Open Access Journals (Sweden)

    Vincent A. R. Camara

    1999-01-01

    Full Text Available The aim of the present study is to investigate the sensitivity of empirical Bayes estimates of the reliability function with respect to changing of the loss function. In addition to applying some of the basic analytical results on empirical Bayes reliability obtained with the use of the “popular” squared error loss function, we shall derive some expressions corresponding to empirical Bayes reliability estimates obtained with the Higgins–Tsokos, the Harris and our proposed logarithmic loss functions. The concept of efficiency, along with the notion of integrated mean square error, will be used as a criterion to numerically compare our results.

  11. Researching on knowledge architecture of design by analysis based on ASME code

    International Nuclear Information System (INIS)

    Bao Shiyi; Zhou Yu; He Shuyan

    2003-01-01

    The quality of knowledge-based system's knowledge architecture is one of decisive factors of knowledge-based system's validity and rationality. For designing the ASME code knowledge based system, this paper presents a knowledge acquisition method which is extracting knowledge through document analysis consulted domain experts' knowledge. Then the paper describes knowledge architecture of design by analysis based on the related rules in ASME code. The knowledge of the knowledge architecture is divided into two categories: one is empirical knowledge, and another is ASME code knowledge. Applied as the basement of the knowledge architecture, a general procedural process of design by analysis that is met the engineering design requirements and designers' conventional mode is generalized and explained detailed in the paper. For the sake of improving inference efficiency and concurrent computation of KBS, a kind of knowledge Petri net (KPN) model is proposed and adopted in expressing the knowledge architecture. Furthermore, for validating and verifying of the empirical rules, five knowledge validation and verification theorems are given in the paper. Moreover the research production is applicable to design the knowledge architecture of ASME codes or other engineering standards. (author)

  12. Reliability analysis of reinforced concrete grids with nonlinear material behavior

    Energy Technology Data Exchange (ETDEWEB)

    Neves, Rodrigo A [EESC-USP, Av. Trabalhador Sao Carlense, 400, 13566-590 Sao Carlos (Brazil); Chateauneuf, Alaa [LaMI-UBP and IFMA, Campus de Clermont-Fd, Les Cezeaux, BP 265, 63175 Aubiere cedex (France)]. E-mail: alaa.chateauneuf@ifma.fr; Venturini, Wilson S [EESC-USP, Av. Trabalhador Sao Carlense, 400, 13566-590 Sao Carlos (Brazil)]. E-mail: venturin@sc.usp.br; Lemaire, Maurice [LaMI-UBP and IFMA, Campus de Clermont-Fd, Les Cezeaux, BP 265, 63175 Aubiere cedex (France)

    2006-06-15

    Reinforced concrete grids are usually used to support large floor slabs. These grids are characterized by a great number of critical cross-sections, where the overall failure is usually sudden. However, nonlinear behavior of concrete leads to the redistribution of internal forces and accurate reliability assessment becomes mandatory. This paper presents a reliability study on reinforced concrete (RC) grids based on coupling Monte Carlo simulations with the response surface techniques. This approach allows us to analyze real RC grids with large number of failure components. The response surface is used to evaluate the structural safety by using first order reliability methods. The application to simple grids shows the interest of the proposed method and the role of moment redistribution in the reliability assessment.

  13. Analysis of travel time reliability on Indiana interstates.

    Science.gov (United States)

    2009-09-15

    Travel-time reliability is a key performance measure in any transportation system. It is a : measure of quality of travel time experienced by transportation system users and reflects the efficiency : of the transportation system to serve citizens, bu...

  14. Development of a Conservative Model Validation Approach for Reliable Analysis

    Science.gov (United States)

    2015-01-01

    CIE 2015 August 2-5, 2015, Boston, Massachusetts, USA [DRAFT] DETC2015-46982 DEVELOPMENT OF A CONSERVATIVE MODEL VALIDATION APPROACH FOR RELIABLE...obtain a conservative simulation model for reliable design even with limited experimental data. Very little research has taken into account the...3, the proposed conservative model validation is briefly compared to the conventional model validation approach. Section 4 describes how to account

  15. The Archaeology of Architecture. New models of analysis applied to structures of Alta Andalusia in the Iberian period

    OpenAIRE

    Sánchez, Julia

    1998-01-01

    New theories of architectural space, based on the philosophy of Lao-Tsé emerged at the end of nineteenth century. Interior space was now considered the core of architecture. Developing concepts of the movement of the human body in this space, new contributions focused on the detailed study of architecture have led to the creation of a new discipline called the Archaeology of Architecture. New models of analysis, based on access and visibility, are applied to the interior space of Iberian dome...

  16. CARES/PC - CERAMICS ANALYSIS AND RELIABILITY EVALUATION OF STRUCTURES

    Science.gov (United States)

    Szatmary, S. A.

    1994-01-01

    The beneficial properties of structural ceramics include their high-temperature strength, light weight, hardness, and corrosion and oxidation resistance. For advanced heat engines, ceramics have demonstrated functional abilities at temperatures well beyond the operational limits of metals. This is offset by the fact that ceramic materials tend to be brittle. When a load is applied, their lack of significant plastic deformation causes the material to crack at microscopic flaws, destroying the component. CARES/PC performs statistical analysis of data obtained from the fracture of simple, uniaxial tensile or flexural specimens and estimates the Weibull and Batdorf material parameters from this data. CARES/PC is a subset of the program CARES (COSMIC program number LEW-15168) which calculates the fast-fracture reliability or failure probability of ceramic components utilizing the Batdorf and Weibull models to describe the effects of multi-axial stress states on material strength. CARES additionally requires that the ceramic structure be modeled by a finite element program such as MSC/NASTRAN or ANSYS. The more limited CARES/PC does not perform fast-fracture reliability estimation of components. CARES/PC estimates ceramic material properties from uniaxial tensile or from three- and four-point bend bar data. In general, the parameters are obtained from the fracture stresses of many specimens (30 or more are recommended) whose geometry and loading configurations are held constant. Parameter estimation can be performed for single or multiple failure modes by using the least-squares analysis or the maximum likelihood method. Kolmogorov-Smirnov and Anderson-Darling goodness-of-fit tests measure the accuracy of the hypothesis that the fracture data comes from a population with a distribution specified by the estimated Weibull parameters. Ninety-percent confidence intervals on the Weibull parameters and the unbiased value of the shape parameter for complete samples are provided

  17. 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)

  18. Reliability analysis for the creep rupture mode of failure

    International Nuclear Information System (INIS)

    Vaidyanathan, S.

    1975-01-01

    An analytical study has been carried out to relate the factors of safety employed in the design of a component to the probability of failure in the thermal creep rupture mode. The analysis considers the statistical variations in the operating temperature, stress and rupture time, and applies the life fraction damage criterion as the indicator of failure. Typical results for solution annealed type 304-stainless steel material for the temperature and stress variations expected in an LMFBR environment have been obtained. The analytical problem was solved by considering the joint distribution of the independent variables and deriving the distribution for the function associated with the probability of failure by integrating over proper regions as dictated by the deterministic design rule. This leads to a triple integral for the final probability of failure where the coefficients of variation associated with the temperature, stress and rupture time distributions can be specified by the user. The derivation is general, and can be used for time varying stress histories and the case of irradiated material where the rupture time varies with accumulated fluence. Example calculations applied to solution annealed type 304 stainless steel material have been carried out for an assumed coefficient of variation of 2% for temperature and 6% for stress. The results show that the probability of failure associated with dependent stress intensity limits specified in the ASME Boiler and Pressure Vessel Section III Code Case 1592 is less than 5x10 -8 . Rupture under thermal creep conditions is a highly complicated phenomenon. It is believed that the present study will help in quantizing the reliability to be expected with deterministic design factors of safety

  19. INFORMATION ARCHITECTURE ANALYSIS USING BUSINESS INTELLIGENCE TOOLS BASED ON THE INFORMATION NEEDS OF EXECUTIVES

    Directory of Open Access Journals (Sweden)

    Fabricio Sobrosa Affeldt

    2013-08-01

    Full Text Available Devising an information architecture system that enables an organization to centralize information regarding its operational, managerial and strategic performance is one of the challenges currently facing information technology. The present study aimed to analyze an information architecture system developed using Business Intelligence (BI technology. The analysis was performed based on a questionnaire enquiring as to whether the information needs of executives were met during the process. A theoretical framework was applied consisting of information architecture and BI technology, using a case study methodology. Results indicated that the transaction processing systems studied did not meet the information needs of company executives. Information architecture using data warehousing, online analytical processing (OLAP tools and data mining may provide a more agile means of meeting these needs. However, some items must be included and others modified, in addition to improving the culture of information use by company executives.

  20. Analysis and design of software ecosystem architectures – Towards the 4S telemedicine ecosystem

    DEFF Research Database (Denmark)

    Christensen, Henrik Bærbak; Hansen, Klaus Marius; Kyng, Morten

    2014-01-01

    performed a descriptive, revelatory case study of the Danish telemedicine ecosystem and for ii), we experimentally designed, implemented, and evaluated the architecture of 4S. Results We contribute in three areas. First, we define the software ecosystem architecture concept that captures organization......, and application stove-pipes that inhibit the adoption of telemedical solutions. To which extent can a software ecosystem approach to telemedicine alleviate this? Objective In this article, we define the concept of software ecosystem architecture as the structure(s) of a software ecosystem comprising elements...... experience in creating and evolving the 4S telemedicine ecosystem. Conclusion The concept of software ecosystem architecture can be used analytically and constructively in respectively the analysis and design of software ecosystems....

  1. Modeling, analysis and optimization of network-on-chip communication architectures

    CERN Document Server

    Ogras, Umit Y

    2013-01-01

    Traditionally, design space exploration for Systems-on-Chip (SoCs) has focused on the computational aspects of the problem at hand. However, as the number of components on a single chip and their performance continue to increase, the communication architecture plays a major role in the area, performance and energy consumption of the overall system. As a result, a shift from computation-based to communication-based design becomes mandatory. Towards this end, network-on-chip (NoC) communication architectures have emerged recently as a promising alternative to classical bus and point-to-point communication architectures. This book explores outstanding research problems related to modeling, analysis and optimization of NoC communication architectures. More precisely, we present novel design methodologies, software tools and FPGA prototypes to aid the design of application-specific NoCs.

  2. Reliability analysis of a sensitive and independent stabilometry parameter set.

    Science.gov (United States)

    Nagymáté, Gergely; Orlovits, Zsanett; Kiss, Rita M

    2018-01-01

    Recent studies have suggested reduced independent and sensitive parameter sets for stabilometry measurements based on correlation and variance analyses. However, the reliability of these recommended parameter sets has not been studied in the literature or not in every stance type used in stabilometry assessments, for example, single leg stances. The goal of this study is to evaluate the test-retest reliability of different time-based and frequency-based parameters that are calculated from the center of pressure (CoP) during bipedal and single leg stance for 30- and 60-second measurement intervals. Thirty healthy subjects performed repeated standing trials in a bipedal stance with eyes open and eyes closed conditions and in a single leg stance with eyes open for 60 seconds. A force distribution measuring plate was used to record the CoP. The reliability of the CoP parameters was characterized by using the intraclass correlation coefficient (ICC), standard error of measurement (SEM), minimal detectable change (MDC), coefficient of variation (CV) and CV compliance rate (CVCR). Based on the ICC, SEM and MDC results, many parameters yielded fair to good reliability values, while the CoP path length yielded the highest reliability (smallest ICC > 0.67 (0.54-0.79), largest SEM% = 19.2%). Usually, frequency type parameters and extreme value parameters yielded poor reliability values. There were differences in the reliability of the maximum CoP velocity (better with 30 seconds) and mean power frequency (better with 60 seconds) parameters between the different sampling intervals.

  3. Reliability analysis of a sensitive and independent stabilometry parameter set

    Science.gov (United States)

    Nagymáté, Gergely; Orlovits, Zsanett

    2018-01-01

    Recent studies have suggested reduced independent and sensitive parameter sets for stabilometry measurements based on correlation and variance analyses. However, the reliability of these recommended parameter sets has not been studied in the literature or not in every stance type used in stabilometry assessments, for example, single leg stances. The goal of this study is to evaluate the test-retest reliability of different time-based and frequency-based parameters that are calculated from the center of pressure (CoP) during bipedal and single leg stance for 30- and 60-second measurement intervals. Thirty healthy subjects performed repeated standing trials in a bipedal stance with eyes open and eyes closed conditions and in a single leg stance with eyes open for 60 seconds. A force distribution measuring plate was used to record the CoP. The reliability of the CoP parameters was characterized by using the intraclass correlation coefficient (ICC), standard error of measurement (SEM), minimal detectable change (MDC), coefficient of variation (CV) and CV compliance rate (CVCR). Based on the ICC, SEM and MDC results, many parameters yielded fair to good reliability values, while the CoP path length yielded the highest reliability (smallest ICC > 0.67 (0.54–0.79), largest SEM% = 19.2%). Usually, frequency type parameters and extreme value parameters yielded poor reliability values. There were differences in the reliability of the maximum CoP velocity (better with 30 seconds) and mean power frequency (better with 60 seconds) parameters between the different sampling intervals. PMID:29664938

  4. 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

  5. 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)

  6. Improvement of human reliability analysis method for PRA

    International Nuclear Information System (INIS)

    Tanji, Junichi; Fujimoto, Haruo

    2013-09-01

    It is required to refine human reliability analysis (HRA) method by, for example, incorporating consideration for the cognitive process of operator into the evaluation of diagnosis errors and decision-making errors, as a part of the development and improvement of methods used in probabilistic risk assessments (PRAs). JNES has been developed a HRA method based on ATHENA which is suitable to handle the structured relationship among diagnosis errors, decision-making errors and operator cognition process. This report summarizes outcomes obtained from the improvement of HRA method, in which enhancement to evaluate how the plant degraded condition affects operator cognitive process and to evaluate human error probabilities (HEPs) which correspond to the contents of operator tasks is made. In addition, this report describes the results of case studies on the representative accident sequences to investigate the applicability of HRA method developed. HEPs of the same accident sequences are also estimated using THERP method, which is most popularly used HRA method, and comparisons of the results obtained using these two methods are made to depict the differences of these methods and issues to be solved. Important conclusions obtained are as follows: (1) Improvement of HRA method using operator cognitive action model. Clarification of factors to be considered in the evaluation of human errors, incorporation of degraded plant safety condition into HRA and investigation of HEPs which are affected by the contents of operator tasks were made to improve the HRA method which can integrate operator cognitive action model into ATHENA method. In addition, the detail of procedures of the improved method was delineated in the form of flowchart. (2) Case studies and comparison with the results evaluated by THERP method. Four operator actions modeled in the PRAs of representative BWR5 and 4-loop PWR plants were selected and evaluated as case studies. These cases were also evaluated using

  7. Application of Metric-based Software Reliability Analysis to Example Software

    International Nuclear Information System (INIS)

    Kim, Man Cheol; Smidts, Carol

    2008-07-01

    The software reliability of TELLERFAST ATM software is analyzed by using two metric-based software reliability analysis methods, a state transition diagram-based method and a test coverage-based method. The procedures for the software reliability analysis by using the two methods and the analysis results are provided in this report. It is found that the two methods have a relation of complementary cooperation, and therefore further researches on combining the two methods to reflect the benefit of the complementary cooperative effect to the software reliability analysis are recommended

  8. 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...

  9. 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...

  10. Long term reliability analysis of standby diesel generators

    International Nuclear Information System (INIS)

    Winfield, D.J.

    1988-01-01

    The long term reliability of 11 diesel generators of 125 to 250 kV A size has been analysed from 26 years of data base information on individual diesel service as standby power supplies for the Chalk River research reactor facilities. Failure to start on demand and failure to run data is presented and failure by diesel subsystem and multiple failures are also analysed. A brief comparison is made with reliability studies of larger diesel generator units used for standby power service in nuclear power plants. (author)

  11. Technical information report: Plasma melter operation, reliability, and maintenance analysis

    International Nuclear Information System (INIS)

    Hendrickson, D.W.

    1995-01-01

    This document provides a technical report of operability, reliability, and maintenance of a plasma melter for low-level waste vitrification, in support of the Hanford Tank Waste Remediation System (TWRS) Low-Level Waste (LLW) Vitrification Program. A process description is provided that minimizes maintenance and downtime and includes material and energy balances, equipment sizes and arrangement, startup/operation/maintence/shutdown cycle descriptions, and basis for scale-up to a 200 metric ton/day production facility. Operational requirements are provided including utilities, feeds, labor, and maintenance. Equipment reliability estimates and maintenance requirements are provided which includes a list of failure modes, responses, and consequences

  12. Embedded mechatronic systems 1 analysis of failures, predictive reliability

    CERN Document Server

    El Hami, Abdelkhalak

    2015-01-01

    In operation, mechatronics embedded systems are stressed by loads of different causes: climate (temperature, humidity), vibration, electrical and electromagnetic. These stresses in components which induce failure mechanisms should be identified and modeled for better control. AUDACE is a collaborative project of the cluster Mov'eo that address issues specific to mechatronic reliability embedded systems. AUDACE means analyzing the causes of failure of components of mechatronic systems onboard. The goal of the project is to optimize the design of mechatronic devices by reliability. The projec

  13. Total Longitudinal Moment Calculation and Reliability Analysis of Yacht Structures

    Science.gov (United States)

    Zhi, Wenzheng; Lin, Shaofen

    In order to check the reliability of the yacht in FRP (Fiber Reinforce Plastic) materials, in this paper, the vertical force and the calculation method of the overall longitudinal bending moment on yacht was analyzed. Specially, this paper focuses on the impact of speed on the still water bending moment on yacht. Then considering the mechanical properties of the cap type stiffeners in composite materials, the ultimate bearing capacity of the yacht has been worked out, finally the reliability of the yacht was calculated with using response surface methodology. The result can be used in yacht design and yacht driving.

  14. Reliability modeling and analysis of smart power systems

    CERN Document Server

    Karki, Rajesh; Verma, Ajit Kumar

    2014-01-01

    The volume presents the research work in understanding, modeling and quantifying the risks associated with different ways of implementing smart grid technology in power systems in order to plan and operate a modern power system with an acceptable level of reliability. Power systems throughout the world are undergoing significant changes creating new challenges to system planning and operation in order to provide reliable and efficient use of electrical energy. The appropriate use of smart grid technology is an important drive in mitigating these problems and requires considerable research acti

  15. 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.

  16. A reliable method for the stability analysis of structures ...

    African Journals Online (AJOL)

    The detection of structural configurations with singular tangent stiffness matrix is essential because they can be unstable. The secondary paths, especially in unstable buckling, can play the most important role in the loss of stability and collapse of the structure. A new method for reliable detection and accurate computation of ...

  17. Windfarm Generation Assessment for ReliabilityAnalysis of Power Systems

    DEFF Research Database (Denmark)

    Negra, Nicola Barberis; Holmstrøm, Ole; Bak-Jensen, Birgitte

    2007-01-01

    Due to the fast development of wind generation in the past ten years, increasing interest has been paid to techniques for assessing different aspects of power systems with a large amount of installed wind generation. One of these aspects concerns power system reliability. Windfarm modelling plays...

  18. Windfarm generation assessment for reliability analysis of power systems

    DEFF Research Database (Denmark)

    Negra, N.B.; Holmstrøm, O.; Bak-Jensen, B.

    2007-01-01

    Due to the fast development of wind generation in the past ten years, increasing interest has been paid to techniques for assessing different aspects of power systems with a large amount of installed wind generation. One of these aspects concerns power system reliability. Windfarm modelling plays...

  19. A comparative reliability analysis of ETCS train radio communications

    NARCIS (Netherlands)

    Hermanns, H.; Becker, B.; Jansen, D.N.; Damm, W.; Usenko, Y.S.; Fränzle, M.; Olderog, E.-R.; Podelski, A.; Wilhelm, R.

    StoCharts have been proposed as a UML statechart extension for performance and dependability evaluation, and were applied in the context of train radio reliability assessment to show the principal tractability of realistic cases with this approach. In this paper, we extend on this bare feasibility

  20. Erratum: Comparative Analysis of Some Reliability Characteristics of ...

    African Journals Online (AJOL)

    ... are analyzed using kolmogorov's forward equation method. Comparisons are performed for specific values of system parameters. Finally, the configurations are ranked based on MTSF and ( AV(∞)) and the results show that configuration 3 is optimal. Keywords: Reliability, Availability, Deterioration, Repair, Replacement.

  1. Reliability analysis of common hazardous waste treatment processes

    International Nuclear Information System (INIS)

    Waters, R.D.

    1993-05-01

    Five hazardous waste treatment processes are analyzed probabilistically using Monte Carlo simulation to elucidate the relationships between process safety factors and reliability levels. The treatment processes evaluated are packed tower aeration, reverse osmosis, activated sludge, upflow anaerobic sludge blanket, and activated carbon adsorption

  2. Reliability analysis of common hazardous waste treatment processes

    Energy Technology Data Exchange (ETDEWEB)

    Waters, Robert D. [Vanderbilt Univ., Nashville, TN (United States)

    1993-05-01

    Five hazardous waste treatment processes are analyzed probabilistically using Monte Carlo simulation to elucidate the relationships between process safety factors and reliability levels. The treatment processes evaluated are packed tower aeration, reverse osmosis, activated sludge, upflow anaerobic sludge blanket, and activated carbon adsorption.

  3. Reliability of Computer Analysis of Electrocardiograms (ECG) of ...

    African Journals Online (AJOL)

    Background: Computer programmes have been introduced to electrocardiography (ECG) with most physicians in Africa depending on computer interpretation of ECG. This study was undertaken to evaluate the reliability of computer interpretation of the 12-Lead ECG in the Black race. Methodology: Using the SCHILLER ...

  4. Connecting Architecture and Implementation

    Science.gov (United States)

    Buchgeher, Georg; Weinreich, Rainer

    Software architectures are still typically defined and described independently from implementation. To avoid architectural erosion and drift, architectural representation needs to be continuously updated and synchronized with system implementation. Existing approaches for architecture representation like informal architecture documentation, UML diagrams, and Architecture Description Languages (ADLs) provide only limited support for connecting architecture descriptions and implementations. Architecture management tools like Lattix, SonarJ, and Sotoarc and UML-tools tackle this problem by extracting architecture information directly from code. This approach works for low-level architectural abstractions like classes and interfaces in object-oriented systems but fails to support architectural abstractions not found in programming languages. In this paper we present an approach for linking and continuously synchronizing a formalized architecture representation to an implementation. The approach is a synthesis of functionality provided by code-centric architecture management and UML tools and higher-level architecture analysis approaches like ADLs.

  5. Reliability analysis of the epidural spinal cord compression scale.

    Science.gov (United States)

    Bilsky, Mark H; Laufer, Ilya; Fourney, Daryl R; Groff, Michael; Schmidt, Meic H; Varga, Peter Paul; Vrionis, Frank D; Yamada, Yoshiya; Gerszten, Peter C; Kuklo, Timothy R

    2010-09-01

    The evolution of imaging techniques, along with highly effective radiation options has changed the way metastatic epidural tumors are treated. While high-grade epidural spinal cord compression (ESCC) frequently serves as an indication for surgical decompression, no consensus exists in the literature about the precise definition of this term. The advancement of the treatment paradigms in patients with metastatic tumors for the spine requires a clear grading scheme of ESCC. The degree of ESCC often serves as a major determinant in the decision to operate or irradiate. The purpose of this study was to determine the reliability and validity of a 6-point, MR imaging-based grading system for ESCC. To determine the reliability of the grading scale, a survey was distributed to 7 spine surgeons who participate in the Spine Oncology Study Group. The MR images of 25 cervical or thoracic spinal tumors were distributed consisting of 1 sagittal image and 3 axial images at the identical level including T1-weighted, T2-weighted, and Gd-enhanced T1-weighted images. The survey was administered 3 times at 2-week intervals. The inter- and intrarater reliability was assessed. The inter- and intrarater reliability ranged from good to excellent when surgeons were asked to rate the degree of spinal cord compression using T2-weighted axial images. The T2-weighted images were superior indicators of ESCC compared with T1-weighted images with and without Gd. The ESCC scale provides a valid and reliable instrument that may be used to describe the degree of ESCC based on T2-weighted MR images. This scale accounts for recent advances in the treatment of spinal metastases and may be used to provide an ESCC classification scheme for multicenter clinical trial and outcome studies.

  6. 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

  7. 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

  8. EZ-Rhizo software: the gateway to root architecture analysis.

    Science.gov (United States)

    Armengaud, Patrick

    2009-02-01

    Plants are sessile organisms that have to cope with the available nutritional resources and environmental constraints in the place where they germinate. To fully exploit their nearby resources, they have evolved a highly plastic and responsive root system. Adaptations to limited nutrients include a wide range of specific root responses, e.g., the emergence of new root types, root branching or specific growth of lateral roots. These root system architecture (RSA) features are of utmost importance when investigating the underlying mechanisms by forward, reverse or quantitative genetic approaches. The EZ-Rhizo software was developed to facilitate such root measurements in a fast, simple and accurate way. The performances of EZ-Rhizo in providing about 20 primary and derived RSA parameters were illustrated by looking at natural variability across 23 Arabidopsis accessions. The different RSA profiles obtained from plants grown in favorable condition illustrated the wide reservoir of natural genetic resources underlying specific features of root growth. This diversity was used here to correlate the RSA genetic variability with growth, development and environmental properties of accession origins.

  9. 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.

  10. 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

  11. 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

  12. Reliability evaluation of nuclear power plants by fault tree analysis

    International Nuclear Information System (INIS)

    Iwao, H.; Otsuka, T.; Fujita, I.

    1993-01-01

    As a work sponsored by the Ministry of International Trade and Industry, the Safety Information Research Center of NUPEC, using reliability data based on the operational experience of the domestic LWR Plants, has implemented FTA for the standard PWRs and BWRs in Japan with reactor scram due to system failures being at the top event. Up to this point, we have obtained the FT chart and minimal cut set for each type of system failure for qualitative evaluation, and we have estimated system unavailability, Fussell-Vesely importance and risk worth for components for quantitative evaluation. As the second stage of a series in our reliability evaluation work, another program was started to establish a support system. The aim of this system is to assist foreign and domestic plants in creating countermeasures when incidents occur, by providing them with the necessary information using the above analytical method and its results. (author)

  13. Reliability Analysis of Timber Structures through NDT Data Upgrading

    DEFF Research Database (Denmark)

    Sousa, Hélder; Sørensen, John Dalsgaard; Kirkegaard, Poul Henning

    The first part of this document presents, in chapter 2, a description of timber characteristics and common used NDT and MDT for timber elements. Stochastic models for timber properties and damage accumulation models are also referred. According to timber’s properties a framework is proposed...... for a safety reassessment procedure. For that purpose a theoretical background for structural reliability assessment including probabilistic concepts for structural systems and stochastic models are given in chapter 3. System models, both series and parallel systems, are presented as well as methods...... for robustness are dealt in chapter 5. The second part of this document begins in chapter 6, where a practical application of the premise definitions and methodologies is given through the implementation of upgraded models with NDT and MDT data. Structural life-cycle is, therefore, assessed and reliability...

  14. Reliability analysis of numerical simulation in near field behavior

    International Nuclear Information System (INIS)

    Kobayashi, Akira; Yamamoto, Kiyohito; Chijimatsu, Masakazu; Fujita, Tomoo

    2008-01-01

    The uncertainties of the boundary conditions, the elastic modulus and Poisson's ratio on the mechanical behavior at near field of high level radioactive waste repository were examined. The method used to examine the error propagation was the first order second moment method. The reliability of the maximum principal stress, maximum shear stress at crown of the tunnel and the minimum principal stress at spring line was examined for one million years. For elastic model, the reliability of the maximum shear stress gradually decreased while that of the maximum principle stress increased. That of the minimum principal stress was relatively low for one million years. This tendency was similar to that from the damage model. (author)

  15. Reliability Analysis of Public Survey in Satisfaction with Nuclear Safety

    Energy Technology Data Exchange (ETDEWEB)

    Park, Moon Soo; Moon, Joo Hyun; Kang, Chang Sun [Seoul National Univ., Seoul (Korea, Republic of)

    2005-07-01

    Korea Institute of Nuclear Safety (KINS) carried out a questionnaire survey on public's understanding nuclear safety and regulation in order to grasp public acceptance for nuclear energy. The survey was planned to help to analyze public opinion on nuclear energy and provide basic data for advertising strategy and policy development. In this study, based on results of the survey, the reliability of the survey was evaluated according to each nuclear site.

  16. Reliability analysis of Airbus A-330 computer flight management system

    OpenAIRE

    Fajmut, Metod

    2010-01-01

    Diploma thesis deals with digitized, computerized flight control system »Fly-by-wire« and security aspects of the computer system of an aircraft Airbus A330. As for space and military aircraft structures is also in commercial airplanes, much of the financial contribution devoted to reliability. Conventional aircraft control systems have, and some are still, to rely on mechanical and hydraulic connections between the controls on aircraft operated by the pilot and control surfaces. But newer a...

  17. Reliability Analysis of Public Survey in Satisfaction with Nuclear Safety

    International Nuclear Information System (INIS)

    Park, Moon Soo; Moon, Joo Hyun; Kang, Chang Sun

    2005-01-01

    Korea Institute of Nuclear Safety (KINS) carried out a questionnaire survey on public's understanding nuclear safety and regulation in order to grasp public acceptance for nuclear energy. The survey was planned to help to analyze public opinion on nuclear energy and provide basic data for advertising strategy and policy development. In this study, based on results of the survey, the reliability of the survey was evaluated according to each nuclear site

  18. Launch and Assembly Reliability Analysis for Human Space Exploration Missions

    Science.gov (United States)

    Cates, Grant; Gelito, Justin; Stromgren, Chel; Cirillo, William; Goodliff, Kandyce

    2012-01-01

    NASA's future human space exploration strategy includes single and multi-launch missions to various destinations including cis-lunar space, near Earth objects such as asteroids, and ultimately Mars. Each campaign is being defined by Design Reference Missions (DRMs). Many of these missions are complex, requiring multiple launches and assembly of vehicles in orbit. Certain missions also have constrained departure windows to the destination. These factors raise concerns regarding the reliability of launching and assembling all required elements in time to support planned departure. This paper describes an integrated methodology for analyzing launch and assembly reliability in any single DRM or set of DRMs starting with flight hardware manufacturing and ending with final departure to the destination. A discrete event simulation is built for each DRM that includes the pertinent risk factors including, but not limited to: manufacturing completion; ground transportation; ground processing; launch countdown; ascent; rendezvous and docking, assembly, and orbital operations leading up to trans-destination-injection. Each reliability factor can be selectively activated or deactivated so that the most critical risk factors can be identified. This enables NASA to prioritize mitigation actions so as to improve mission success.

  19. Reliability analysis of a complex standby redundant systems

    International Nuclear Information System (INIS)

    Subramanian, R.; Anantharaman, V.

    1995-01-01

    In any redundant system, the state of the standby unit is usually taken to be hot, warm or cold. In this paper, we present a new model of a two unit standby system wherein the standby unit is put in cold state for a certain amount of time before it is allowed to become warm. Upon failure of the online unit, the standby unit, if in warm state, instantaneously starts operating online; if it is in cold state, an emergency switching is made which takes it to warm state (and hence online) either instantaneously or non-instantaneously--each with some probability; if it is under repair, the system breaks down. Assuming all the associated distributions to be general except that of the life time of the standby unit in the warm state, various reliability characteristics that are of interest to reliability engineers and system designers are derived. A comprehensive cost function is also constructed and is then optimized with respect to three different control parameters numerically. In addition numerical results are presented to illustrate the behaviour of the various reliability characteristics derived

  20. Abstract interfaces for data analysis - component architecture for data analysis tools

    International Nuclear Information System (INIS)

    Barrand, G.; Binko, P.; Doenszelmann, M.; Pfeiffer, A.; Johnson, A.

    2001-01-01

    The fast turnover of software technologies, in particular in the domain of interactivity (covering user interface and visualisation), makes it difficult for a small group of people to produce complete and polished software-tools before the underlying technologies make them obsolete. At the HepVis'99 workshop, a working group has been formed to improve the production of software tools for data analysis in HENP. Beside promoting a distributed development organisation, one goal of the group is to systematically design a set of abstract interfaces based on using modern OO analysis and OO design techniques. An initial domain analysis has come up with several categories (components) found in typical data analysis tools: Histograms, Ntuples, Functions, Vectors, Fitter, Plotter, analyzer and Controller. Special emphasis was put on reducing the couplings between the categories to a minimum, thus optimising re-use and maintainability of any component individually. The interfaces have been defined in Java and C++ and implementations exist in the form of libraries and tools using C++ (Anaphe/Lizard, OpenScientist) and Java (Java Analysis Studio). A special implementation aims at accessing the Java libraries (through their Abstract Interfaces) from C++. The authors give an overview of the architecture and design of the various components for data analysis as discussed in AIDA

  1. Bridging Human Reliability Analysis and Psychology, Part 1: The Psychological Literature Review for the IDHEAS Method

    Energy Technology Data Exchange (ETDEWEB)

    April M. Whaley; Stacey M. L. Hendrickson; Ronald L. Boring; Jeffrey C. Joe; Katya L. Le Blanc; Jing Xing

    2012-06-01

    In response to Staff Requirements Memorandum (SRM) SRM-M061020, the U.S. Nuclear Regulatory Commission (NRC) is sponsoring work to update the technical basis underlying human reliability analysis (HRA) in an effort to improve the robustness of HRA. The ultimate goal of this work is to develop a hybrid of existing methods addressing limitations of current HRA models and in particular issues related to intra- and inter-method variabilities and results. This hybrid method is now known as the Integrated Decision-tree Human Event Analysis System (IDHEAS). Existing HRA methods have looked at elements of the psychological literature, but there has not previously been a systematic attempt to translate the complete span of cognition from perception to action into mechanisms that can inform HRA. Therefore, a first step of this effort was to perform a literature search of psychology, cognition, behavioral science, teamwork, and operating performance to incorporate current understanding of human performance in operating environments, thus affording an improved technical foundation for HRA. However, this literature review went one step further by mining the literature findings to establish causal relationships and explicit links between the different types of human failures, performance drivers and associated performance measures ultimately used for quantification. This is the first of two papers that detail the literature review (paper 1) and its product (paper 2). This paper describes the literature review and the high-level architecture used to organize the literature review, and the second paper (Whaley, Hendrickson, Boring, & Xing, these proceedings) describes the resultant cognitive framework.

  2. 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.)

  3. 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

  4. Product Lifecycle Management Architecture: A Model Based Systems Engineering Analysis.

    Energy Technology Data Exchange (ETDEWEB)

    Noonan, Nicholas James [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-07-01

    This report is an analysis of the Product Lifecycle Management (PLM) program. The analysis is centered on a need statement generated by a Nuclear Weapons (NW) customer. The need statement captured in this report creates an opportunity for the PLM to provide a robust service as a solution. Lifecycles for both the NW and PLM are analyzed using Model Based System Engineering (MBSE).

  5. State Analysis: A Control Architecture View of Systems Engineering

    Science.gov (United States)

    Rasmussen, Robert D.

    2005-01-01

    A viewgraph presentation on the state analysis process is shown. The topics include: 1) Issues with growing complexity; 2) Limits of common practice; 3) Exploiting a control point of view; 4) A glimpse at the State Analysis process; 5) Synergy with model-based systems engineering; and 6) Bridging the systems to software gap.

  6. 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...

  7. Reliability analysis of reactor systems by applying probability method; Analiza pouzdanosti reaktorskih sistema primenom metoda verovatnoce

    Energy Technology Data Exchange (ETDEWEB)

    Milivojevic, S [Institute of Nuclear Sciences Boris Kidric, Vinca, Beograd (Serbia and Montenegro)

    1974-12-15

    Probability method was chosen for analysing the reactor system reliability is considered realistic since it is based on verified experimental data. In fact this is a statistical method. The probability method developed takes into account the probability distribution of permitted levels of relevant parameters and their particular influence on the reliability of the system as a whole. The proposed method is rather general, and was used for problem of thermal safety analysis of reactor system. This analysis enables to analyze basic properties of the system under different operation conditions, expressed in form of probability they show the reliability of the system on the whole as well as reliability of each component.

  8. 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

  9. 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.

  10. 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.

  11. 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

  12. 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

  13. 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.

  14. 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.

  15. 3D PLUS HI-REL DDR2 Termination Regulator Module- A Building Block Function for High Reliability SDRAM DDR2 System Architecture

    Science.gov (United States)

    Perrot, Nicolas; Dubus, Patrick; Garcia-Sanchez, Esther

    2015-09-01

    Memory system architectures using DDR2 technology need to be compliant with JEDEC JESD8-15A standard [1]. Therefore a bus termination regulator able to sink and source current while regulating VTT voltage is used for this purpose. Such module has been developed by 3D PLUS and is the first space qualified DDR Termination Regulator (DDR2-TR) available on the market. It is based on an innovative Bang-Bang regulation principle, chosen for its speed performance and to guarantee an output voltage that remains within the predefined limits regardless of any output current transients. The output filter type is selected to make the module rugged to any overload condition without complex protection circuits. The module has been specifically designed for low input voltage, low noise and high reliability systems where space is a key consideration. The module uses the 3D PLUS SIP (System-In-Package) technology embedding 3 stacked PCBs. No external filters or decoupling capacitors are needed.

  16. Design and reliability analysis of a novel laser acupuncture device

    Science.gov (United States)

    Pan, Boan; Zhong, Fulin; Zhao, Ke; Li, Ting

    2018-02-01

    Acupuncture has a long history of more than 2000 years in China. However, traditional acupuncture adopts metallic needles which may bring discomfort and pricking to patients. Laser acupuncture (LA) is a non-invasive and painless way to achieve some therapeutic effects. And compared to traditional acupuncture, LA is free from infection. Taking these advantages of LA into consideration, we innovatively developed a portable laser acupuncture device with therapy part and detection part together. Therapy part sends out laser at the wavelength of 650 nm onto special acupoints of patients. And detection part includes integrated light-emitting diode (LED, 735/805/850 nm) and photodiode (OPT101). The detection part is used for the data collection for calculation of hemodynamic parameters based on near-infrared spectroscopy (NIRS). In this work, we carried out current-power test for sensitivity of therapy part. And we also conducted liquid-model optical experiment and arm blocking test for the sensitivity and effectiveness of detection part. The final results demonstrated great potential and reliability of the novel laser acupuncture device. In the future, we will apply this device in clinical applications to verify the effectiveness of the device and improve the reliability for more treatment of diseases.

  17. Time-dependent reliability analysis of flood defences

    International Nuclear Information System (INIS)

    Buijs, F.A.; Hall, J.W.; Sayers, P.B.; Gelder, P.H.A.J.M. van

    2009-01-01

    This paper describes the underlying theory and a practical process for establishing time-dependent reliability models for components in a realistic and complex flood defence system. Though time-dependent reliability models have been applied frequently in, for example, the offshore, structural safety and nuclear industry, application in the safety-critical field of flood defence has to date been limited. The modelling methodology involves identifying relevant variables and processes, characterisation of those processes in appropriate mathematical terms, numerical implementation, parameter estimation and prediction. A combination of stochastic, hierarchical and parametric processes is employed. The approach is demonstrated for selected deterioration mechanisms in the context of a flood defence system. The paper demonstrates that this structured methodology enables the definition of credible statistical models for time-dependence of flood defences in data scarce situations. In the application of those models one of the main findings is that the time variability in the deterioration process tends to be governed the time-dependence of one or a small number of critical attributes. It is demonstrated how the need for further data collection depends upon the relevance of the time-dependence in the performance of the flood defence system.

  18. On Bayesian reliability analysis with informative priors and censoring

    International Nuclear Information System (INIS)

    Coolen, F.P.A.

    1996-01-01

    In the statistical literature many methods have been presented to deal with censored observations, both within the Bayesian and non-Bayesian frameworks, and such methods have been successfully applied to, e.g., reliability problems. Also, in reliability theory it is often emphasized that, through shortage of statistical data and possibilities for experiments, one often needs to rely heavily on judgements of engineers, or other experts, for which means Bayesian methods are attractive. It is therefore important that such judgements can be elicited easily to provide informative prior distributions that reflect the knowledge of the engineers well. In this paper we focus on this aspect, especially on the situation that the judgements of the consulted engineers are based on experiences in environments where censoring has also been present previously. We suggest the use of the attractive interpretation of hyperparameters of conjugate prior distributions when these are available for assumed parametric models for lifetimes, and we show how one may go beyond the standard conjugate priors, using similar interpretations of hyper-parameters, to enable easier elicitation when censoring has been present in the past. This may even lead to more flexibility for modelling prior knowledge than when using standard conjugate priors, whereas the disadvantage of more complicated calculations that may be needed to determine posterior distributions play a minor role due to the advanced mathematical and statistical software that is widely available these days

  19. The mathematics of the modernist villa architectural analysis using space syntax and isovists

    CERN Document Server

    Ostwald, Michael J

    2018-01-01

    This book presents the first detailed mathematical analysis of the social, cognitive and experiential properties of Modernist domestic architecture. The Modern Movement in architecture, which came to prominence during the first half of the twentieth century, may have been famous for its functional forms and machine-made aesthetic, but it also sought to challenge the way people inhabit, understand and experience space. Ludwig Mies van der Rohe’s buildings were not only minimalist and transparent, they were designed to subvert traditional social hierarchies. Frank Lloyd Wright’s organic Modernism not only attempted to negotiate a more responsive relationship between nature and architecture, but also shape the way people experience space. Richard Neutra’s Californian Modernism is traditionally celebrated for its sleek, geometric forms, but his intention was to use design to support a heightened understanding of context. Glenn Murcutt’s pristine pavilions, seemingly the epitome of regional Modernism, actu...

  20. 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

  1. Architecture of collaborating frameworks simulation, visualisation, user interface and analysis

    CERN Document Server

    Pfeier, A; Ferrero-Merlino, B; Giannitrapani, R; Longo, F; Nieminen, P; Pia, M G; Santin, G

    2001-01-01

    The Anaphe project is an ongoing effort to provide an Object Oriented software environment for data analysis in HENP experiments. A range of commercial and public domain libraries is used to cover basic functionalities; on top of these libraries a set of HENP-specific C++ class libraries for histogram management, fitting, plotting and ntuple-like data analysis has been developed. In order to comply with the user requirements for a command-line driven tool, we have chosen to use a scripting language (Python) as the front-end for a data analysis tool. The loose coupling provided by the consequent use of (AIDA compliant) Abstract Interfaces for each component in combination with the use of shared libraries for their implementation provides an easy integration of existing libraries into modern scripting languages thus allowing for rapid application development. This integration is simplified even further using a specialised toolkit (SWIG) to create "shadow classes" for the Python language, which map the definitio...

  2. 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)

  3. 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)

  4. Development of an analysis rule of diagnosis error for standard method of human reliability analysis

    International Nuclear Information System (INIS)

    Jeong, W. D.; Kang, D. I.; Jeong, K. S.

    2003-01-01

    This paper presents the status of development of Korea standard method for Human Reliability Analysis (HRA), and proposed a standard procedure and rules for the evaluation of diagnosis error probability. The quality of KSNP HRA was evaluated using the requirement of ASME PRA standard guideline, and the design requirement for the standard HRA method was defined. Analysis procedure and rules, developed so far, to analyze diagnosis error probability was suggested as a part of the standard method. And also a study of comprehensive application was performed to evaluate the suitability of the proposed rules

  5. Emergency diesel generator reliability analysis high flux isotope reactor

    International Nuclear Information System (INIS)

    Merryman, L.; Christie, B.

    1993-01-01

    A program to apply some of the techniques of reliability engineering to the High Flux Isotope Reactor (HFIR) was started on August 8, 1992. Part of the program was to track the conditional probabilities of the emergency diesel generators responding to a valid demand. This was done to determine if the performance of the emergency diesel generators (which are more than 25 years old) has deteriorated. The conditional probabilities of the diesel generators were computed and trended for the period from May 1990 to December 1992. The calculations indicate that the performance of the emergency diesel generators has not deteriorated in recent years, i.e., the conditional probabilities of the emergency diesel generators have been fairly stable over the last few years. This information will be one factor than may be considered in the decision to replace the emergency diesel generators

  6. Reliability analysis of GEM® Premier™ technology: a multicenter study

    Directory of Open Access Journals (Sweden)

    Francesco Faggiano

    2015-10-01

    Full Text Available This paper describes how specific blood gas analyzer characteristics can support the emerging clinical and organizational user’s needs while ensuring patient safety. A oneyear data set from two Italian hospitals was analyzed from 10 different blood gas analyzers. Performance measurements in terms of mean down time (MDT were calculated to show how technical characteristics declared by the manufacturer compare to the analyzer availability in real clinical settings. Results show a high level of reliability for the analyzed technology, associated with very low MDT of each sensor integrated in the cartridge. Moreover, results show a high level of efficiency in cartridge usage. Such results are consistent with the specification of the GEM® Premier™ maintenance- free technology and are particularly relevant in the point-of-care testing setting.

  7. The role of human reliability analysis for enhancing crew performance

    International Nuclear Information System (INIS)

    Hannaman, G.W.; Joksimovich, V.; Worledge, D.H.; Spurgin, A.J.

    1986-01-01

    This paper summarizes some aspects of EPRI-sponsored research undertaken in support of improving the PRA technology. In particular, the consideration of how human actions that impact accident sequences can be analyzed in a systematic way to supplement the type of ergonomic studies normally carried out in support of control room design. The HRA/PRA approach described not only identifies the operator information and interface needs, but also helps to identify issues and areas for additional research. The process includes a link to data collections. Preliminary collections of data and analytical benchmark support the idea that such analytical frameworks and models provide support for ranking the importance of various human reliability issues

  8. Towards a non-wired simulator for reliability analysis

    International Nuclear Information System (INIS)

    Jurvillier, I.; Laviron, A.; Blin, A.

    1991-11-01

    This paper outlines the objectives and preliminary results of a research programme aiming to increase the advantages of electronic simulators used for reliability studies of complex systems. Research work has resulted in the design of a device based on an electronic simulator capable of carrying out all types of simulation without the drawback of wiring, as is currently the case. Its performance levels as regards speed are comparable to those of wired simulators and this is its main advantage over studies made on a computer. In addition, the simulator is connected to a computer which greatly increases system flexibility and user-friendliness. The first results obtained illustrate what characteristics can be expected of such a system, both as regards the anticipated computation time and the extended processing capabilities (such as the study of common cause failures). (author) [fr

  9. Towards a non-wired simulator for reliability analysis

    International Nuclear Information System (INIS)

    Blin, A.; Laviron, A.; Jurvillier, I.

    1991-08-01

    This paper outlines the objectives and preliminary results of a research programme aiming to increase the advantages of electronic simulators used for reliability studies of complex systems. Research work has resulted in the design of a device based on an electronic simulator capable of carrying out all types of simulation without the drawback of wiring, as is currently the case. Its performance levels as regards speed are comparable to those of wired simulators and this is its main advantage over studies made on a computer. In addition, the simulator is connected to a computer which greatly increases system flexibility and user-friendliness. The first results obtained illustrate what characteristics can be expected of such a system, both as regards the anticipated computation time and the extended processing capabilities (such as the study of common cause failures)

  10. IEEE guide for general principles of reliability analysis of nuclear power generating station protection systems

    International Nuclear Information System (INIS)

    Anon.

    1975-01-01

    Presented is the Institute of Electrical and Electronics Engineers, Inc. (IEEE) guide for general principles of reliability analysis of nuclear power generating station protection systems. The document has been prepared to provide the basic principles needed to conduct a reliability analysis of protection systems. Included is information on qualitative and quantitative analysis, guides for failure data acquisition and use, and guide for establishment of intervals

  11. 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.

  12. 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.

  13. 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)

  14. Low Carbon-Oriented Optimal Reliability Design with Interval Product Failure Analysis and Grey Correlation Analysis

    Directory of Open Access Journals (Sweden)

    Yixiong Feng

    2017-03-01

    Full Text Available The problem of large amounts of carbon emissions causes wide concern across the world, and it has become a serious threat to the sustainable development of the manufacturing industry. The intensive research into technologies and methodologies for green product design has significant theoretical meaning and practical value in reducing the emissions of the manufacturing industry. Therefore, a low carbon-oriented product reliability optimal design model is proposed in this paper: (1 The related expert evaluation information was prepared in interval numbers; (2 An improved product failure analysis considering the uncertain carbon emissions of the subsystem was performed to obtain the subsystem weight taking the carbon emissions into consideration. The interval grey correlation analysis was conducted to obtain the subsystem weight taking the uncertain correlations inside the product into consideration. Using the above two kinds of subsystem weights and different caution indicators of the decision maker, a series of product reliability design schemes is available; (3 The interval-valued intuitionistic fuzzy sets (IVIFSs were employed to select the optimal reliability and optimal design scheme based on three attributes, namely, low carbon, correlation and functions, and economic cost. The case study of a vertical CNC lathe proves the superiority and rationality of the proposed method.

  15. Architectural Narratives

    DEFF Research Database (Denmark)

    Kiib, Hans

    2010-01-01

    a functional framework for these concepts, but tries increasingly to endow the main idea of the cultural project with a spatially aesthetic expression - a shift towards “experience architecture.” A great number of these projects typically recycle and reinterpret narratives related to historical buildings......In this essay, I focus on the combination of programs and the architecture of cultural projects that have emerged within the last few years. These projects are characterized as “hybrid cultural projects,” because they intend to combine experience with entertainment, play, and learning. This essay...... and architectural heritage; another group tries to embed new performative technologies in expressive architectural representation. Finally, this essay provides a theoretical framework for the analysis of the political rationales of these projects and for the architectural representation bridges the gap between...

  16. 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...

  17. Convergence among Data Sources, Response Bias, and Reliability and Validity of a Structured Job Analysis Questionnaire.

    Science.gov (United States)

    Smith, Jack E.; Hakel, Milton D.

    1979-01-01

    Examined are questions pertinent to the use of the Position Analysis Questionnaire: Who can use the PAQ reliably and validly? Must one rely on trained job analysts? Can people having no direct contact with the job use the PAQ reliably and validly? Do response biases influence PAQ responses? (Author/KC)

  18. 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

  19. 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.

  20. Analysis of Statistical Distributions Used for Modeling Reliability and Failure Rate of Temperature Alarm Circuit

    International Nuclear Information System (INIS)

    EI-Shanshoury, G.I.

    2011-01-01

    Several statistical distributions are used to model various reliability and maintainability parameters. The applied distribution depends on the' nature of the data being analyzed. The presented paper deals with analysis of some statistical distributions used in reliability to reach the best fit of distribution analysis. The calculations rely on circuit quantity parameters obtained by using Relex 2009 computer program. The statistical analysis of ten different distributions indicated that Weibull distribution gives the best fit distribution for modeling the reliability of the data set of Temperature Alarm Circuit (TAC). However, the Exponential distribution is found to be the best fit distribution for modeling the failure rate

  1. 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

  2. Reliability analysis of microcomputer boards and computer based systems important to safety of nuclear plants

    International Nuclear Information System (INIS)

    Shrikhande, S.V.; Patil, V.K.; Ganesh, G.; Biswas, B.; Patil, R.K.

    2010-01-01

    Computer Based Systems (CBS) are employed in Indian nuclear plants for protection, control and monitoring purpose. For forthcoming CBS, Reactor Control Division has designed and developed a new standardized family of microcomputer boards qualified to stringent requirements of nuclear industry. These boards form the basic building blocks of CBS. Reliability analysis of these boards is being carried out using analysis package based on MIL-STD-217Plus methodology. The estimated failure rate values of these standardized microcomputer boards will be useful for reliability assessment of these systems. The paper presents reliability analysis of microcomputer boards and case study of a CBS system built using these boards. (author)

  3. 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.

  4. 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.

  5. 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

  6. 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

  7. Analysis of multigrid methods on massively parallel computers: Architectural implications

    Science.gov (United States)

    Matheson, Lesley R.; Tarjan, Robert E.

    1993-01-01

    We study the potential performance of multigrid algorithms running on massively parallel computers with the intent of discovering whether presently envisioned machines will provide an efficient platform for such algorithms. We consider the domain parallel version of the standard V cycle algorithm on model problems, discretized using finite difference techniques in two and three dimensions on block structured grids of size 10(exp 6) and 10(exp 9), respectively. Our models of parallel computation were developed to reflect the computing characteristics of the current generation of massively parallel multicomputers. These models are based on an interconnection network of 256 to 16,384 message passing, 'workstation size' processors executing in an SPMD mode. The first model accomplishes interprocessor communications through a multistage permutation network. The communication cost is a logarithmic function which is similar to the costs in a variety of different topologies. The second model allows single stage communication costs only. Both models were designed with information provided by machine developers and utilize implementation derived parameters. With the medium grain parallelism of the current generation and the high fixed cost of an interprocessor communication, our analysis suggests an efficient implementation requires the machine to support the efficient transmission of long messages, (up to 1000 words) or the high initiation cost of a communication must be significantly reduced through an alternative optimization technique. Furthermore, with variable length message capability, our analysis suggests the low diameter multistage networks provide little or no advantage over a simple single stage communications network.

  8. 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...

  9. Reliability analysis of emergency decay heat removal system of nuclear ship under various accident conditions

    International Nuclear Information System (INIS)

    Matsuoka, Takeshi

    1984-01-01

    A reliability analysis is given for the emergency decay heat removal system of the Nuclear Ship ''Mutsu'' and the emergency sea water cooling system of the Nuclear Ship ''Savannah'', under ten typical nuclear ship accident conditions. Basic event probabilities under these accident conditions are estimated from literature survey. These systems of Mutsu and Savannah have almost the same reliability under the normal condition. The dispersive arrangement of a system is useful to prevent the reduction of the system reliability under the condition of an accident restricted in one room. As for the reliability of these two systems under various accident conditions, it is seen that the configuration and the environmental condition of a system are two main factors which determine the reliability of the system. Furthermore, it was found that, for the evaluation of the effectiveness of safety system of a nuclear ship, it is necessary to evaluate its reliability under various accident conditions. (author)

  10. A Disciplined Architectural Approach to Scaling Data Analysis for Massive, Scientific Data

    Science.gov (United States)

    Crichton, D. J.; Braverman, A. J.; Cinquini, L.; Turmon, M.; Lee, H.; Law, E.

    2014-12-01

    Data collections across remote sensing and ground-based instruments in astronomy, Earth science, and planetary science are outpacing scientists' ability to analyze them. Furthermore, the distribution, structure, and heterogeneity of the measurements themselves pose challenges that limit the scalability of data analysis using traditional approaches. Methods for developing science data processing pipelines, distribution of scientific datasets, and performing analysis will require innovative approaches that integrate cyber-infrastructure, algorithms, and data into more systematic approaches that can more efficiently compute and reduce data, particularly distributed data. This requires the integration of computer science, machine learning, statistics and domain expertise to identify scalable architectures for data analysis. The size of data returned from Earth Science observing satellites and the magnitude of data from climate model output, is predicted to grow into the tens of petabytes challenging current data analysis paradigms. This same kind of growth is present in astronomy and planetary science data. One of the major challenges in data science and related disciplines defining new approaches to scaling systems and analysis in order to increase scientific productivity and yield. Specific needs include: 1) identification of optimized system architectures for analyzing massive, distributed data sets; 2) algorithms for systematic analysis of massive data sets in distributed environments; and 3) the development of software infrastructures that are capable of performing massive, distributed data analysis across a comprehensive data science framework. NASA/JPL has begun an initiative in data science to address these challenges. Our goal is to evaluate how scientific productivity can be improved through optimized architectural topologies that identify how to deploy and manage the access, distribution, computation, and reduction of massive, distributed data, while

  11. Applying reliability centered maintenance analysis principles to inservice testing

    International Nuclear Information System (INIS)

    Flude, J.W.

    1994-01-01

    Federal regulations require nuclear power plants to use inservice test (IST) programs to ensure the operability of safety-related equipment. IST programs are based on American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code requirements. Many of these plants also use Reliability Centered Maintenance (RCM) to optimize system maintenance. ASME Code requirements are hard to change. The process for requesting authority to use an alternate strategy is long and expensive. The difficulties of obtaining this authority make the use of RCM method on safety-related systems not cost effective. An ASME research task force on Risk Based Inservice Testing is investigating changing the Code. The change will allow plants to apply RCM methods to the problem of maintenance strategy selection for safety-related systems. The research task force is working closely with the Codes and Standards sections to develop a process related to the RCM process. Some day plants will be able to use this process to develop more efficient and safer maintenance strategies

  12. The first Superphenix fuel load reliability analysis and validation

    International Nuclear Information System (INIS)

    Marbach, G.; Beche, M.; Pajot, J.

    1986-09-01

    The excellent behavior of PHENIX driver fuel and the burnup values currently reached suggest that the first SUPERPHENIX fuel load will meet the design lifetime. However, to ensure the reliability of the entire load, all the parameters affecting fuel behavior in reactor must be analyzed. For that purpose, we have taken into account all the results of the examination and verifications during the fabrication process of the first load subassemblies. These data concern geometrical parameters or oxide composition as well as the cladding tube and plug weld soundness tests. The objective is to determine the actual dispersion of all the parameters to ensure the absence of failure due to fabrication defects with very high statistical confidence limits. The influence of all the parameters has been investigated for the situations which can occur during power-up, steady-state operation and transients. The fabrication quality allows us to demonstrate that in all cases good behavior criteria for fuel and structure will be maintained. This demonstration is based on calculation code results as well as on validation by specific experiments

  13. Architectural Analysis of Systems Based on the Publisher-Subscriber Style

    Science.gov (United States)

    Ganesun, Dharmalingam; Lindvall, Mikael; Ruley, Lamont; Wiegand, Robert; Ly, Vuong; Tsui, Tina

    2010-01-01

    Architectural styles impose constraints on both the topology and the interaction behavior of involved parties. In this paper, we propose an approach for analyzing implemented systems based on the publisher-subscriber architectural style. From the style definition, we derive a set of reusable questions and show that some of them can be answered statically whereas others are best answered using dynamic analysis. The paper explains how the results of static analysis can be used to orchestrate dynamic analysis. The proposed method was successfully applied on the NASA's Goddard Mission Services Evolution Center (GMSEC) software product line. The results show that the GMSEC has a) a novel reusable vendor-independent middleware abstraction layer that allows the NASA's missions to configure the middleware of interest without changing the publishers' or subscribers' source code, and b) some high priority bugs due to behavioral discrepancies, which were eluded during testing and code reviews, among different implementations of the same APIs for different vendors.

  14. 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.

  15. Software architecture 2

    CERN Document Server

    Oussalah, Mourad Chabanne

    2014-01-01

    Over the past 20 years, software architectures have significantly contributed to the development of complex and distributed systems. Nowadays, it is recognized that one of the critical problems in the design and development of any complex software system is its architecture, i.e. the organization of its architectural elements. Software Architecture presents the software architecture paradigms based on objects, components, services and models, as well as the various architectural techniques and methods, the analysis of architectural qualities, models of representation of architectural templa

  16. Software architecture 1

    CERN Document Server

    Oussalah , Mourad Chabane

    2014-01-01

    Over the past 20 years, software architectures have significantly contributed to the development of complex and distributed systems. Nowadays, it is recognized that one of the critical problems in the design and development of any complex software system is its architecture, i.e. the organization of its architectural elements. Software Architecture presents the software architecture paradigms based on objects, components, services and models, as well as the various architectural techniques and methods, the analysis of architectural qualities, models of representation of architectural template

  17. Analysis methods for structure reliability of piping components

    International Nuclear Information System (INIS)

    Schimpfke, T.; Grebner, H.; Sievers, J.

    2004-01-01

    In the frame of the German reactor safety research program of the Federal Ministry of Economics and Labour (BMWA) GRS has started to develop an analysis code named PROST (PRObabilistic STructure analysis) for estimating the leak and break probabilities of piping systems in nuclear power plants. The long-term objective of this development is to provide failure probabilities of passive components for probabilistic safety analysis of nuclear power plants. Up to now the code can be used for calculating fatigue problems. The paper mentions the main capabilities and theoretical background of the present PROST development and presents some of the results of a benchmark analysis in the frame of the European project NURBIM (Nuclear Risk Based Inspection Methodologies for Passive Components). (orig.)

  18. The Centralized Reliability Data Organization (CREDO); an advanced nuclear reactor reliability, availability, and maintainability data bank and data analysis center

    International Nuclear Information System (INIS)

    Knee, H.E.

    1991-01-01

    The Centralized Reliability Data Organization (CREDO) is a data bank and data analysis center, which since 1985 has been jointly sponsored by the US Department of Energy's (US DOE's) Office of Technology Support Programs and Japan's Power Reactor and Nuclear Fuel Development Corporation (PNC). It focuses on reliability, availability and maintainability (RAM) data for components (e.g. valves, pumps, etc.) operating in advanced nuclear reactor facilities. As originally intended, the purpose of the CREDO system was to provide a centralized source of accurate, up-to-date data and information for use in RAM analyses necessary for meeting DOE's data needs in the areas of advanced reactor safety assessments, design and licensing. In particular, creation of the CREDO system was considered an essential element needed to fulfill the DOE Breeder Reactor Safety Program's commitment of 'identifying and exploiting areas in which probabilistic methods can be developed and used in making reactor safety Research and Development choices and optimizing designs of safety systems'. CREDO and its operation are explained. (author)

  19. Use of computer codes for system reliability analysis

    International Nuclear Information System (INIS)

    Sabek, M.; Gaafar, M.; Poucet, A.

    1988-01-01

    This paper gives a collective summary of the studies performed at the JRC, ISPRA on the use of computer codes for complex systems analysis. The computer codes dealt with are: CAFTS-SALP software package, FRANTIC, FTAP, computer code package RALLY, and BOUNDS codes. Two reference study cases were executed by each code. The results obtained logic/probabilistic analysis as well as computation time are compared

  20. Task analysis and computer aid development for human reliability analysis in nuclear power plants

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, W. C.; Kim, H.; Park, H. S.; Choi, H. H.; Moon, J. M.; Heo, J. Y.; Ham, D. H.; Lee, K. K.; Han, B. T. [Korea Advanced Institute of Science and Technology, Taejeon (Korea)

    2001-04-01

    Importance of human reliability analysis (HRA) that predicts the error's occurrence possibility in a quantitative and qualitative manners is gradually increased by human errors' effects on the system's safety. HRA needs a task analysis as a virtue step, but extant task analysis techniques have the problem that a collection of information about the situation, which the human error occurs, depends entirely on HRA analyzers. The problem makes results of the task analysis inconsistent and unreliable. To complement such problem, KAERI developed the structural information analysis (SIA) that helps to analyze task's structure and situations systematically. In this study, the SIA method was evaluated by HRA experts, and a prototype computerized supporting system named CASIA (Computer Aid for SIA) was developed for the purpose of supporting to perform HRA using the SIA method. Additionally, through applying the SIA method to emergency operating procedures, we derived generic task types used in emergency and accumulated the analysis results in the database of the CASIA. The CASIA is expected to help HRA analyzers perform the analysis more easily and consistently. If more analyses will be performed and more data will be accumulated to the CASIA's database, HRA analyzers can share freely and spread smoothly his or her analysis experiences, and there by the quality of the HRA analysis will be improved. 35 refs., 38 figs., 25 tabs. (Author)