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Sample records for reliable risk assessment

  1. Human reliability assessment and probabilistic risk assessment

    International Nuclear Information System (INIS)

    Embrey, D.E.; Lucas, D.A.

    1989-01-01

    Human reliability assessment (HRA) is used within Probabilistic Risk Assessment (PRA) to identify the human errors (both omission and commission) which have a significant effect on the overall safety of the system and to quantify the probability of their occurrence. There exist a variey of HRA techniques and the selection of an appropriate one is often difficult. This paper reviews a number of available HRA techniques and discusses their strengths and weaknesses. The techniques reviewed include: decompositional methods, time-reliability curves and systematic expert judgement techniques. (orig.)

  2. Reevaluating Interrater Reliability in Offender Risk Assessment

    NARCIS (Netherlands)

    van der Knaap, L.M.; Leenarts, L.E.W.; Born, M.P.; Oosterveld, P.

    2012-01-01

    Offender risk and needs assessment, one of the pillars of the risk-need-responsivity model of offender rehabilitation, usually depends on raters assessing offender risk and needs. The few available studies of interrater reliability in offender risk assessment are, however, limited in the

  3. Reevaluating Interrater Reliability in Offender Risk Assessment

    Science.gov (United States)

    van der Knaap, Leontien M.; Leenarts, Laura E. W.; Born, Marise Ph.; Oosterveld, Paul

    2012-01-01

    Offender risk and needs assessment, one of the pillars of the risk-need-responsivity model of offender rehabilitation, usually depends on raters assessing offender risk and needs. The few available studies of interrater reliability in offender risk assessment are, however, limited in the generalizability of their results. The present study…

  4. Computer-aided reliability and risk assessment

    International Nuclear Information System (INIS)

    Leicht, R.; Wingender, H.J.

    1989-01-01

    Activities in the fields of reliability and risk analyses have led to the development of particular software tools which now are combined in the PC-based integrated CARARA system. The options available in this system cover a wide range of reliability-oriented tasks, like organizing raw failure data in the component/event data bank FDB, performing statistical analysis of those data with the program FDA, managing the resulting parameters in the reliability data bank RDB, and performing fault tree analysis with the fault tree code FTL or evaluating the risk of toxic or radioactive material release with the STAR code. (orig.)

  5. Reliability data collection and use in risk and availability assessment

    International Nuclear Information System (INIS)

    Colombari, V.

    1989-01-01

    For EuReDatA it is a prevailing objective to initiate and support contact between experts, companies and institutions active in reliability engineering and research. Main topics of this 6th EuReDatA Conference are: Reliability data banks; incidents data banks; common cause data; source and propagation of uncertainties; computer aided risk analysis; reliability and incidents data acquisition and processing; human reliability; probabilistic safety and availability assessment; feedback of reliability into system design; data fusion; reliability modeling and techniques; structural and mechanical reliability; consequence modeling; software and electronic reliability; reliability tests. Some conference papers are separately indexed in the database. (HP)

  6. Risk and reliability assessment for telecommunications networks

    Energy Technology Data Exchange (ETDEWEB)

    Wyss, G.D.; Schriner, H.K.; Gaylor, T.R.

    1996-08-01

    Sandia National Laboratories has assembled an interdisciplinary team to explore the applicability of probabilistic logic modeling (PLM) techniques to model network reliability for a wide variety of communications network architectures. The authors have found that the reliability and failure modes of current generation network technologies can be effectively modeled using fault tree PLM techniques. They have developed a ``plug-and-play`` fault tree analysis methodology that can be used to model connectivity and the provision of network services in a wide variety of current generation network architectures. They have also developed an efficient search algorithm that can be used to determine the minimal cut sets of an arbitrarily-interconnected (non-hierarchical) network without the construction of a fault tree model. This paper provides an overview of these modeling techniques and describes how they are applied to networks that exhibit hybrid network structures (i.e., a network in which some areas are hierarchical and some areas are not hierarchical).

  7. 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

  8. Reliability and Probabilistic Risk Assessment - How They Play Together

    Science.gov (United States)

    Safie, Fayssal M.; Stutts, Richard G.; Zhaofeng, Huang

    2015-01-01

    PRA methodology is one of the probabilistic analysis methods that NASA brought from the nuclear industry to assess the risk of LOM, LOV and LOC for launch vehicles. PRA is a system scenario based risk assessment that uses a combination of fault trees, event trees, event sequence diagrams, and probability and statistical data to analyze the risk of a system, a process, or an activity. It is a process designed to answer three basic questions: What can go wrong? How likely is it? What is the severity of the degradation? Since 1986, NASA, along with industry partners, has conducted a number of PRA studies to predict the overall launch vehicles risks. Planning Research Corporation conducted the first of these studies in 1988. In 1995, Science Applications International Corporation (SAIC) conducted a comprehensive PRA study. In July 1996, NASA conducted a two-year study (October 1996 - September 1998) to develop a model that provided the overall Space Shuttle risk and estimates of risk changes due to proposed Space Shuttle upgrades. After the Columbia accident, NASA conducted a PRA on the Shuttle External Tank (ET) foam. This study was the most focused and extensive risk assessment that NASA has conducted in recent years. It used a dynamic, physics-based, integrated system analysis approach to understand the integrated system risk due to ET foam loss in flight. Most recently, a PRA for Ares I launch vehicle has been performed in support of the Constellation program. Reliability, on the other hand, addresses the loss of functions. In a broader sense, reliability engineering is a discipline that involves the application of engineering principles to the design and processing of products, both hardware and software, for meeting product reliability requirements or goals. It is a very broad design-support discipline. It has important interfaces with many other engineering disciplines. Reliability as a figure of merit (i.e. the metric) is the probability that an item will

  9. Risk assessment and reliability for low level radioactive waste disposal

    International Nuclear Information System (INIS)

    Gregory, P.O.; Jones, G.A.

    1986-01-01

    The reliability of critical design features at low-level radioactive waste disposal facilities is a major concern in the licensing of these structures. To date, no systematic methodology has been adopted to evaluate the geotechnical reliability of Uranium Mill Tailings Remedial Action (UMTRA) disposal facilities currently being designed and/or constructed. This paper discusses and critiques the deterministic methods currently used to evaluate UMTRA reliability. Because deterministic methods may not be applicable in some cases because of the unusually long design life of UMTRA facilities, it is proposed that a probabilistic risk assessment-based methodology be used as a secondary method to aid in the evaluating of geotechnical reliability of critical items. Similar methodologies have proven successful in evaluating the reliability of a variety of conventional earth structures. In this paper, an ''acceptable'' level of risk for UMTRA facilities is developed, an evaluation method is presented, and two example applications of the proposed methodology are provided for a generic UMTRA disposal facility. The proposed technique is shown to be a simple method which might be used to aid in reliability evaluations on a selective basis. Finally, other possible applications and the limitations of the proposed methodology are discussed

  10. Improving risk assessment by defining consistent and reliable system scenarios

    Directory of Open Access Journals (Sweden)

    B. Mazzorana

    2009-02-01

    Full Text Available During the entire procedure of risk assessment for hydrologic hazards, the selection of consistent and reliable scenarios, constructed in a strictly systematic way, is fundamental for the quality and reproducibility of the results. However, subjective assumptions on relevant impact variables such as sediment transport intensity on the system loading side and weak point response mechanisms repeatedly cause biases in the results, and consequently affect transparency and required quality standards. Furthermore, the system response of mitigation measures to extreme event loadings represents another key variable in hazard assessment, as well as the integral risk management including intervention planning. Formative Scenario Analysis, as a supplement to conventional risk assessment methods, is a technique to construct well-defined sets of assumptions to gain insight into a specific case and the potential system behaviour. By two case studies, carried out (1 to analyse sediment transport dynamics in a torrent section equipped with control measures, and (2 to identify hazards induced by woody debris transport at hydraulic weak points, the applicability of the Formative Scenario Analysis technique is presented. It is argued that during scenario planning in general and with respect to integral risk management in particular, Formative Scenario Analysis allows for the development of reliable and reproducible scenarios in order to design more specifically an application framework for the sustainable assessment of natural hazards impact. The overall aim is to optimise the hazard mapping and zoning procedure by methodologically integrating quantitative and qualitative knowledge.

  11. 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

  12. 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...

  13. Reliability assessment of competing risks with generalized mixed shock models

    International Nuclear Information System (INIS)

    Rafiee, Koosha; Feng, Qianmei; Coit, David W.

    2017-01-01

    This paper investigates reliability modeling for systems subject to dependent competing risks considering the impact from a new generalized mixed shock model. Two dependent competing risks are soft failure due to a degradation process, and hard failure due to random shocks. The shock process contains fatal shocks that can cause hard failure instantaneously, and nonfatal shocks that impact the system in three different ways: 1) damaging the unit by immediately increasing the degradation level, 2) speeding up the deterioration by accelerating the degradation rate, and 3) weakening the unit strength by reducing the hard failure threshold. While the first impact from nonfatal shocks comes from each individual shock, the other two impacts are realized when the condition for a new generalized mixed shock model is satisfied. Unlike most existing mixed shock models that consider a combination of two shock patterns, our new generalized mixed shock model includes three classic shock patterns. According to the proposed generalized mixed shock model, the degradation rate and the hard failure threshold can simultaneously shift multiple times, whenever the condition for one of these three shock patterns is satisfied. An example using micro-electro-mechanical systems devices illustrates the effectiveness of the proposed approach with sensitivity analysis. - Highlights: • A rich reliability model for systems subject to dependent failures is proposed. • The degradation rate and the hard failure threshold can shift simultaneously. • The shift is triggered by a new generalized mixed shock model. • The shift can occur multiple times under the generalized mixed shock model.

  14. Inter- and intra- observer reliability of risk assessment of repetitive work without an explicit method.

    Science.gov (United States)

    Eliasson, Kristina; Palm, Peter; Nyman, Teresia; Forsman, Mikael

    2017-07-01

    A common way to conduct practical risk assessments is to observe a job and report the observed long term risks for musculoskeletal disorders. The aim of this study was to evaluate the inter- and intra-observer reliability of ergonomists' risk assessments without the support of an explicit risk assessment method. Twenty-one experienced ergonomists assessed the risk level (low, moderate, high risk) of eight upper body regions, as well as the global risk of 10 video recorded work tasks. Intra-observer reliability was assessed by having nine of the ergonomists repeat the procedure at least three weeks after the first assessment. The ergonomists made their risk assessment based on his/her experience and knowledge. The statistical parameters of reliability included agreement in %, kappa, linearly weighted kappa, intraclass correlation and Kendall's coefficient of concordance. The average inter-observer agreement of the global risk was 53% and the corresponding weighted kappa (K w ) was 0.32, indicating fair reliability. The intra-observer agreement was 61% and 0.41 (K w ). This study indicates that risk assessments of the upper body, without the use of an explicit observational method, have non-acceptable reliability. It is therefore recommended to use systematic risk assessment methods to a higher degree. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  15. Reliability and Probabilistic Risk Assessment - How They Play Together

    Science.gov (United States)

    Safie, Fayssal M.; Stutts, Richard; Huang, Zhaofeng

    2015-01-01

    The objective of this presentation is to discuss the PRA process and the reliability engineering discipline, their differences and similarities, and how they are used as complimentary analyses to support design and flight decisions.

  16. Use of reliability engineering tools in safety and risk assessment of nuclear facilities

    Energy Technology Data Exchange (ETDEWEB)

    Raso, Amanda Laureano; Vasconcelos, Vanderley de; Marques, Raíssa Oliveira; Soares, Wellington Antonio; Mesquita, Amir Zacarias, E-mail: amandaraso@hotmail.com, E-mail: vasconv@cdtn.br, E-mail: raissaomarques@gmail.com, E-mail: soaresw@cdtn.br, E-mail: amir@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil). Serviço de Tecnologia de Reatores

    2017-07-01

    Safety, reliability and availability are fundamental criteria in design, construction and operation of nuclear facilities, as nuclear power plants. Deterministic and probabilistic risk assessments of such facilities are required by regulatory authorities in order to meet licensing regulations, contributing to assure safety, as well as reduce costs and environmental impacts. Probabilistic Risk Assessment has become an important part of licensing requirements of the nuclear power plants in Brazil and in the world. Risk can be defined as a qualitative and/or quantitative assessment of accident sequence frequencies (or probabilities) and their consequences. Risk management is a systematic application of management policies, procedures and practices to identify, analyze, plan, implement, control, communicate and document risks. Several tools and computer codes must be combined, in order to estimate both probabilities and consequences of accidents. Event Tree Analysis (ETA), Fault Tree Analysis (FTA), Reliability Block Diagrams (RBD), and Markov models are examples of evaluation tools that can support the safety and risk assessment for analyzing process systems, identifying potential accidents, and estimating consequences. Because of complexity of such analyzes, specialized computer codes are required, such as the reliability engineering software develop by Reliasoft® Corporation. BlockSim (FTA, RBD and Markov models), RENO (ETA and consequence assessment), Weibull++ (life data and uncertainty analysis), and Xfmea (qualitative risk assessment) are some codes that can be highlighted. This work describes an integrated approach using these tools and software to carry out reliability, safety, and risk assessment of nuclear facilities, as well as, and application example. (author)

  17. Use of reliability engineering tools in safety and risk assessment of nuclear facilities

    International Nuclear Information System (INIS)

    Raso, Amanda Laureano; Vasconcelos, Vanderley de; Marques, Raíssa Oliveira; Soares, Wellington Antonio; Mesquita, Amir Zacarias

    2017-01-01

    Safety, reliability and availability are fundamental criteria in design, construction and operation of nuclear facilities, as nuclear power plants. Deterministic and probabilistic risk assessments of such facilities are required by regulatory authorities in order to meet licensing regulations, contributing to assure safety, as well as reduce costs and environmental impacts. Probabilistic Risk Assessment has become an important part of licensing requirements of the nuclear power plants in Brazil and in the world. Risk can be defined as a qualitative and/or quantitative assessment of accident sequence frequencies (or probabilities) and their consequences. Risk management is a systematic application of management policies, procedures and practices to identify, analyze, plan, implement, control, communicate and document risks. Several tools and computer codes must be combined, in order to estimate both probabilities and consequences of accidents. Event Tree Analysis (ETA), Fault Tree Analysis (FTA), Reliability Block Diagrams (RBD), and Markov models are examples of evaluation tools that can support the safety and risk assessment for analyzing process systems, identifying potential accidents, and estimating consequences. Because of complexity of such analyzes, specialized computer codes are required, such as the reliability engineering software develop by Reliasoft® Corporation. BlockSim (FTA, RBD and Markov models), RENO (ETA and consequence assessment), Weibull++ (life data and uncertainty analysis), and Xfmea (qualitative risk assessment) are some codes that can be highlighted. This work describes an integrated approach using these tools and software to carry out reliability, safety, and risk assessment of nuclear facilities, as well as, and application example. (author)

  18. 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

  19. Proceeding of 35th domestic symposium on applications of structural reliability and risk assessment methods to nuclear power plants

    International Nuclear Information System (INIS)

    2005-06-01

    As the 35th domestic symposium of Atomic Energy Research Committee, the Japan Welding Engineering Society, the symposium was held titled as Applications of structural reliability/risk assessment methods to nuclear energy'. Six speakers gave lectures titled as 'Structural reliability and risk assessment methods', 'Risk-informed regulation of US nuclear energy and role of probabilistic risk assessment', 'Reliability and risk assessment methods in chemical plants', 'Practical structural design methods based on reliability in architectural and civil areas', 'Maintenance activities based on reliability in thermal power plants' and 'LWR maintenance strategies based on Probabilistic Fracture Mechanics'. (T. Tanaka)

  20. Relevance and reliability of experimental data in human health risk assessment of pesticides.

    Science.gov (United States)

    Kaltenhäuser, Johanna; Kneuer, Carsten; Marx-Stoelting, Philip; Niemann, Lars; Schubert, Jens; Stein, Bernd; Solecki, Roland

    2017-08-01

    Evaluation of data relevance, reliability and contribution to uncertainty is crucial in regulatory health risk assessment if robust conclusions are to be drawn. Whether a specific study is used as key study, as additional information or not accepted depends in part on the criteria according to which its relevance and reliability are judged. In addition to GLP-compliant regulatory studies following OECD Test Guidelines, data from peer-reviewed scientific literature have to be evaluated in regulatory risk assessment of pesticide active substances. Publications should be taken into account if they are of acceptable relevance and reliability. Their contribution to the overall weight of evidence is influenced by factors including test organism, study design and statistical methods, as well as test item identification, documentation and reporting of results. Various reports make recommendations for improving the quality of risk assessments and different criteria catalogues have been published to support evaluation of data relevance and reliability. Their intention was to guide transparent decision making on the integration of the respective information into the regulatory process. This article describes an approach to assess the relevance and reliability of experimental data from guideline-compliant studies as well as from non-guideline studies published in the scientific literature in the specific context of uncertainty and risk assessment of pesticides. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  1. Reliability of risk assessment measures used in sexually violent predator proceedings.

    Science.gov (United States)

    Miller, Cailey S; Kimonis, Eva R; Otto, Randy K; Kline, Suzonne M; Wasserman, Adam L

    2012-12-01

    The field interrater reliability of three assessment tools frequently used by mental health professionals when evaluating sex offenders' risk for reoffending--the Psychopathy Checklist-Revised (PCL-R), the Minnesota Sex Offender Screening Tool-Revised (MnSOST-R) and the Static-99-was examined within the context of sexually violent predator program proceedings. Rater agreement was highest for the Static--99 (intraclass correlation coefficient [ICC₁] = .78) and lowest for the PCL-R (ICC₁ = .60; MnSOST-R ICC₁ = .74), although all instruments demonstrated lower field reliability than that reported in their test manuals. Findings raise concerns about the reliability of risk assessment tools that are used to inform judgments of risk in high-stake sexually violent predator proceedings. Implications for future research and suggestions for improving evaluator training to increase accuracy when informing legal decision making are discussed.

  2. Development of reliability and probabilistic safety assessment program RiskA

    International Nuclear Information System (INIS)

    Wu, Yican

    2015-01-01

    Highlights: • There are four parts in the structure of RiskA. User input part lets users input the PSA model and some necessary data by GUI or model transformation tool. In calculation engine part, fault tree analysis, event tree analysis, uncertainty analysis, sensitivity analysis, importance analysis and failure mode and effects analysis are supplied. User output part outputs the analysis results, user customized reports and some other data. The last part includes reliability database, some other common tools and help documents. • RiskA has several advanced features. Extensible framework makes it easy to add any new functions, making RiskA to be a large platform of reliability and probabilistic safety assessment. It is very fast to analysis fault tree in RiskA because many advanced algorithm improvement were made. Many model formats can be imported and exported, which made the PSA model in the commercial software can be easily transformed to adapt RiskA platform. Web-based co-modeling let several users in different places work together whenever they are online. • The comparison between RiskA and other mature PSA codes (e.g. CAFTA, RiskSpectrum, XFTA) has demonstrated that the calculation and analysis of RiskA is correct and efficient. Based on the development of this code package, many applications of safety and reliability analysis of some research reactors and nuclear power plants were performed. The development of RiskA appears to be of realistic and potential value for academic research and practical operation safety management of nuclear power plants in China and abroad. - Abstract: PSA (probabilistic safety assessment) software, the indispensable tool in nuclear safety assessment, has been widely used. An integrated reliability and PSA program named RiskA has been developed by FDS Team. RiskA supplies several standard PSA modules including fault tree analysis, event tree analysis, uncertainty analysis, failure mode and effect analysis and reliability

  3. Evaluation of the Validity and Reliability of the Waterlow Pressure Ulcer Risk Assessment Scale.

    Science.gov (United States)

    Charalambous, Charalambos; Koulori, Agoritsa; Vasilopoulos, Aristidis; Roupa, Zoe

    2018-04-01

    Prevention is the ideal strategy to tackle the problem of pressure ulcers. Pressure ulcer risk assessment scales are one of the most pivotal measures applied to tackle the problem, much criticisms has been developed regarding the validity and reliability of these scales. To investigate the validity and reliability of the Waterlow pressure ulcer risk assessment scale. The methodology used is a narrative literature review, the bibliography was reviewed through Cinahl, Pubmed, EBSCO, Medline and Google scholar, 26 scientific articles where identified. The articles where chosen due to their direct correlation with the objective under study and their scientific relevance. The construct and face validity of the Waterlow appears adequate, but with regards to content validity changes in the category age and gender can be beneficial. The concurrent validity cannot be assessed. The predictive validity of the Waterlow is characterized by high specificity and low sensitivity. The inter-rater reliability has been demonstrated to be inadequate, this may be due to lack of clear definitions within the categories and differentiating level of knowledge between the users. Due to the limitations presented regarding the validity and reliability of the Waterlow pressure ulcer risk assessment scale, the scale should be used in conjunction with clinical assessment to provide optimum results.

  4. Evaluation of the Validity and Reliability of the Waterlow Pressure Ulcer Risk Assessment Scale

    Science.gov (United States)

    Charalambous, Charalambos; Koulori, Agoritsa; Vasilopoulos, Aristidis; Roupa, Zoe

    2018-01-01

    Introduction Prevention is the ideal strategy to tackle the problem of pressure ulcers. Pressure ulcer risk assessment scales are one of the most pivotal measures applied to tackle the problem, much criticisms has been developed regarding the validity and reliability of these scales. Objective To investigate the validity and reliability of the Waterlow pressure ulcer risk assessment scale. Method The methodology used is a narrative literature review, the bibliography was reviewed through Cinahl, Pubmed, EBSCO, Medline and Google scholar, 26 scientific articles where identified. The articles where chosen due to their direct correlation with the objective under study and their scientific relevance. Results The construct and face validity of the Waterlow appears adequate, but with regards to content validity changes in the category age and gender can be beneficial. The concurrent validity cannot be assessed. The predictive validity of the Waterlow is characterized by high specificity and low sensitivity. The inter-rater reliability has been demonstrated to be inadequate, this may be due to lack of clear definitions within the categories and differentiating level of knowledge between the users. Conclusion Due to the limitations presented regarding the validity and reliability of the Waterlow pressure ulcer risk assessment scale, the scale should be used in conjunction with clinical assessment to provide optimum results. PMID:29736104

  5. A Closed-Form Technique for the Reliability and Risk Assessment of Wind Turbine Systems

    Directory of Open Access Journals (Sweden)

    Leonardo Dueñas-Osorio

    2012-06-01

    Full Text Available This paper proposes a closed-form method to evaluate wind turbine system reliability and associated failure consequences. Monte Carlo simulation, a widely used approach for system reliability assessment, usually requires large numbers of computational experiments, while existing analytical methods are limited to simple system event configurations with a focus on average values of reliability metrics. By analyzing a wind turbine system and its components in a combinatorial yet computationally efficient form, the proposed approach provides an entire probability distribution of system failure that contains all possible configurations of component failure and survival events. The approach is also capable of handling unique component attributes such as downtime and repair cost needed for risk estimations, and enables sensitivity analysis for quantifying the criticality of individual components to wind turbine system reliability. Applications of the technique are illustrated by assessing the reliability of a 12-subassembly turbine system. In addition, component downtimes and repair costs of components are embedded in the formulation to compute expected annual wind turbine unavailability and repair cost probabilities, and component importance metrics useful for maintenance planning and research prioritization. Furthermore, this paper introduces a recursive solution to closed-form method and applies this to a 45-component turbine system. The proposed approach proves to be computationally efficient and yields vital reliability information that could be readily used by wind farm stakeholders for decision making and risk management.

  6. How to interpret safety critical failures in risk and reliability assessments

    International Nuclear Information System (INIS)

    Selvik, Jon Tømmerås; Signoret, Jean-Pierre

    2017-01-01

    Management of safety systems often receives high attention due to the potential for industrial accidents. In risk and reliability literature concerning such systems, and particularly concerning safety-instrumented systems, one frequently comes across the term ‘safety critical failure’. It is a term associated with the term ‘critical failure’, and it is often deduced that a safety critical failure refers to a failure occurring in a safety critical system. Although this is correct in some situations, it is not matching with for example the mathematical definition given in ISO/TR 12489:2013 on reliability modeling, where a clear distinction is made between ‘safe failures’ and ‘dangerous failures’. In this article, we show that different interpretations of the term ‘safety critical failure’ exist, and there is room for misinterpretations and misunderstandings regarding risk and reliability assessments where failure information linked to safety systems are used, and which could influence decision-making. The article gives some examples from the oil and gas industry, showing different possible interpretations of the term. In particular we discuss the link between criticality and failure. The article points in general to the importance of adequate risk communication when using the term, and gives some clarification on interpretation in risk and reliability assessments.

  7. Methodology for risk assessment and reliability applied for pipeline engineering design and industrial valves operation

    Energy Technology Data Exchange (ETDEWEB)

    Silveira, Dierci [Universidade Federal Fluminense (UFF), Volta Redonda, RJ (Brazil). Escola de Engenharia Industrial e Metalurgia. Lab. de Sistemas de Producao e Petroleo e Gas], e-mail: dsilveira@metal.eeimvr.uff.br; Batista, Fabiano [CICERO, Rio das Ostras, RJ (Brazil)

    2009-07-01

    Two kinds of situations may be distinguished for estimating the operating reliability when maneuvering industrial valves and the probability of undesired events in pipelines and industrial plants: situations in which the risk is identified in repetitive cycles of operations and situations in which there is a permanent hazard due to project configurations introduced by decisions during the engineering design definition stage. The estimation of reliability based on the influence of design options requires the choice of a numerical index, which may include a composite of human operating parameters based on biomechanics and ergonomics data. We first consider the design conditions under which the plant or pipeline operator reliability concepts can be applied when operating industrial valves, and then describe in details the ergonomics and biomechanics risks that would lend itself to engineering design database development and human reliability modeling and assessment. This engineering design database development and reliability modeling is based on a group of engineering design and biomechanics parameters likely to lead to over-exertion forces and working postures, which are themselves associated with the functioning of a particular plant or pipeline. This approach to construct based on ergonomics and biomechanics for a more common industrial valve positioning in the plant layout is proposed through the development of a methodology to assess physical efforts and operator reach, combining various elementary operations situations. These procedures can be combined with the genetic algorithm modeling and four elements of the man-machine systems: the individual, the task, the machinery and the environment. The proposed methodology should be viewed not as competing to traditional reliability and risk assessment bur rather as complementary, since it provides parameters related to physical efforts values for valves operation and workspace design and usability. (author)

  8. Investigating the reliability and validity of the waterlow risk assessment scale: a literature review.

    LENUS (Irish Health Repository)

    Walsh, Breda

    2012-02-01

    The aim of this review was to examine health literature on the reliability and validity of the Waterlow pressure sore assessment scale. A systematic review of published studies relating to the topic was conducted and literature was examined for its relevancy to the topic under investigation. Findings suggest that despite the availability of over 40 assessment tools, the Waterlow assessment scale is the most frequently used by health care staff. Research suggests that the Waterlow Scale is an unreliable method of assessing individuals at risk of pressure sore development with all studies indicating a poor interrater reliability status. Its validity has also been criticized because of its high-sensitivity but low-specificity levels.

  9. Investigating the reliability and validity of the waterlow risk assessment scale: a literature review.

    LENUS (Irish Health Repository)

    Walsh, Breda

    2011-05-01

    The aim of this review was to examine health literature on the reliability and validity of the Waterlow pressure sore assessment scale. A systematic review of published studies relating to the topic was conducted and literature was examined for its relevancy to the topic under investigation. Findings suggest that despite the availability of over 40 assessment tools, the Waterlow assessment scale is the most frequently used by health care staff. Research suggests that the Waterlow Scale is an unreliable method of assessing individuals at risk of pressure sore development with all studies indicating a poor interrater reliability status. Its validity has also been criticized because of its high-sensitivity but low-specificity levels.

  10. Validity and Reliability of Persian Version of Johns Hopkins Fall Risk Assessment Tool among Aged People

    Directory of Open Access Journals (Sweden)

    hadi hojati

    2018-04-01

    Full Text Available Background & Aim: It is crucial to identify aged patients in risk of falls in clinical settings. Johns Hopkins Fall Risk Assessment Tool (JHFRAT is one of most applied international instrument to assess elderly patients for the risk of falls. The aim of this study was to evaluate reliability and internal consistency of the JHFRAT. Methods & Materials: In this cross-sectional study for validity assessment of the tool, WHO’s standard protocol was applied for translation-back translation of the tool. Face and content validity of the tool was confirmed by ten person of expert faculty members for its applicability in clinical setting. In this pilot study, the inclusion criteria were being 60 or more years old, hospitalized in the last 8 hours prior to assessment and in proper cognitive condition assessed by MMSE. Subjects of the study were (n=70 elderly patients who were newly hospitalized in Shahroud Emam Hossein Hospital. Data were analyzed using SPSS software- version 16. Internal consistency of the tool was calculated by Cronbach’s alpha. Results: According to the results of the study Persian version of JHFRAT was a valid tool for application on clinical setting. The Persian version of the tool had Cronbach’s alpha equal to 0/733. Conclusion: Based on the findings of the current study, it can be concluded that Persian version of the JHFRAT is a valid and reliable tool to be applied for assessment of elderly senior citizens on admission in any clinical settings.

  11. Systamatic approach to integration of a human reliability analysis into a NPP probabalistic risk assessment

    International Nuclear Information System (INIS)

    Fragola, J.R.

    1984-01-01

    This chapter describes the human reliability analysis tasks which were employed in the evaluation of the overall probability of an internal flood sequence and its consequences in terms of disabling vulnerable risk significant equipment. Topics considered include the problem familiarization process, the identification and classification of key human interactions, a human interaction review of potential initiators, a maintenance and operations review, human interaction identification, quantification model selection, the definition of operator-induced sequences, the quantification of specific human interactions, skill- and rule-based interactions, knowledge-based interactions, and the incorporation of human interaction-related events into the event tree structure. It is concluded that an integrated approach to the analysis of human interaction within the context of a Probabilistic Risk Assessment (PRA) is feasible

  12. Modeling and Quantification of Team Performance in Human Reliability Analysis for Probabilistic Risk Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Jeffrey C. JOe; Ronald L. Boring

    2014-06-01

    Probabilistic Risk Assessment (PRA) and Human Reliability Assessment (HRA) are important technical contributors to the United States (U.S.) Nuclear Regulatory Commission’s (NRC) risk-informed and performance based approach to regulating U.S. commercial nuclear activities. Furthermore, all currently operating commercial NPPs in the U.S. are required by federal regulation to be staffed with crews of operators. Yet, aspects of team performance are underspecified in most HRA methods that are widely used in the nuclear industry. There are a variety of "emergent" team cognition and teamwork errors (e.g., communication errors) that are 1) distinct from individual human errors, and 2) important to understand from a PRA perspective. The lack of robust models or quantification of team performance is an issue that affects the accuracy and validity of HRA methods and models, leading to significant uncertainty in estimating HEPs. This paper describes research that has the objective to model and quantify team dynamics and teamwork within NPP control room crews for risk informed applications, thereby improving the technical basis of HRA, which improves the risk-informed approach the NRC uses to regulate the U.S. commercial nuclear industry.

  13. Application of structural reliability and risk assessment to life prediction and life extension decision making

    International Nuclear Information System (INIS)

    Meyer, T.A.; Balkey, K.R.; Bishop, B.A.

    1987-01-01

    There can be numerous uncertainties involved in performing component life assessments. In addition, sufficient data may be unavailable to make a useful life prediction. Structural Reliability and Risk Assessment (SRRA) is primarily an analytical methodology or tool that quantifies the impact of uncertainties on the structural life of plant components and can address the lack of data in component life prediction. As a prelude to discussing the technical aspects of SRRA, a brief review of general component life prediction methods is first made so as to better develop an understanding of the role of SRRA in such evaluations. SRRA is then presented as it is applied in component life evaluations with example applications being discussed for both nuclear and non-nuclear components

  14. A shortened version of the THERP/Handbook approach to human reliability analysis for probabilistic risk assessment

    International Nuclear Information System (INIS)

    Swain, A.D.

    1986-01-01

    The approach to human reliability analysis (HRA) known as THERP/Handbook has been applied to several probabilistic risk assessments (PRAs) of nuclear power plants (NPPs) and other complex systems. The approach is based on a thorough task analysis of the man-machine interfaces, including the interactions among the people, involved in the operations being assessed. The idea is to assess fully the underlying performance shaping factors (PSFs) and dependence effects which result either in reliable or unreliable human performance

  15. Safety and reliability assessment

    International Nuclear Information System (INIS)

    1979-01-01

    This report contains the papers delivered at the course on safety and reliability assessment held at the CSIR Conference Centre, Scientia, Pretoria. The following topics were discussed: safety standards; licensing; biological effects of radiation; what is a PWR; safety principles in the design of a nuclear reactor; radio-release analysis; quality assurance; the staffing, organisation and training for a nuclear power plant project; event trees, fault trees and probability; Automatic Protective Systems; sources of failure-rate data; interpretation of failure data; synthesis and reliability; quantification of human error in man-machine systems; dispersion of noxious substances through the atmosphere; criticality aspects of enrichment and recovery plants; and risk and hazard analysis. Extensive examples are given as well as case studies

  16. The Validity and Reliability of the Turkish Version of the Neonatal Skin Risk Assessment Scale.

    Science.gov (United States)

    Sari, Çiğdem; Altay, Naime

    2017-03-01

    The study created a Turkish translation of the Neonatal Skin Risk Assessment Scale (NSRAS) that was developed by Huffines and Longsdon in 1997. Study authors used a cross-sectional survey design in order to determine the validity and reliability of the Turkish translation. The study was conducted at the neonatal intensive care unit of a university hospital in Ankara between March 15 and June 30, 2014. The research sample included 130 neonatal assessments from 17 patients. Data were collected by questionnaire regarding the characteristics of the participating neonates, 7 nurse observers, and the NSRAS and its subarticles. After translation and back-translation were performed to assess language validity of the scale, necessary corrections were made in line with expert suggestions, and content validity was ensured. Internal consistency of the scale was assessed by its homogeneity, Cronbach's α, and subarticle-general scale grade correlation. Cronbach's α for the scale overall was .88, and Cronbach's α values for the subarticles were between .83 and .90. Results showed a positive relationship among all the subarticles and the overall NSRAS scale grade (P Kaiser-Meyer-Olkin analysis was applied for sample sufficiency, and Bartlett test analysis was applied in order to assess the factor analysis of the sample. The Kaiser-Meyer-Olkin coefficient was 0.73, and the χ value found according to the Bartlett test was statistically significant at an advanced level (P < .05). In the 6 subarticles of the scale and in the general scale total grade, a high, positive, and significant relationship among the grades given by the researcher and the nurse observers was found (P < .05). The Turkish NSRAS is reliable and valid.

  17. Uncertainty Quantification in the Reliability and Risk Assessment of Generation IV Reactors: Final Scientific/Technical Report

    International Nuclear Information System (INIS)

    Vierow, Karen; Aldemir, Tunc

    2009-01-01

    The project entitled, 'Uncertainty Quantification in the Reliability and Risk Assessment of Generation IV Reactors', was conducted as a DOE NERI project collaboration between Texas A and M University and The Ohio State University between March 2006 and June 2009. The overall goal of the proposed project was to develop practical approaches and tools by which dynamic reliability and risk assessment techniques can be used to augment the uncertainty quantification process in probabilistic risk assessment (PRA) methods and PRA applications for Generation IV reactors. This report is the Final Scientific/Technical Report summarizing the project.

  18. Uncertainty Quantification in the Reliability and Risk Assessment of Generation IV Reactors: Final Scientific/Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Vierow, Karen; Aldemir, Tunc

    2009-09-10

    The project entitled, “Uncertainty Quantification in the Reliability and Risk Assessment of Generation IV Reactors”, was conducted as a DOE NERI project collaboration between Texas A&M University and The Ohio State University between March 2006 and June 2009. The overall goal of the proposed project was to develop practical approaches and tools by which dynamic reliability and risk assessment techniques can be used to augment the uncertainty quantification process in probabilistic risk assessment (PRA) methods and PRA applications for Generation IV reactors. This report is the Final Scientific/Technical Report summarizing the project.

  19. Novel Threat-risk Index Using Probabilistic Risk Assessment and Human Reliability Analysis - Final Report

    Energy Technology Data Exchange (ETDEWEB)

    George A. Beitel

    2004-02-01

    In support of a national need to improve the current state-of-the-art in alerting decision makers to the risk of terrorist attack, a quantitative approach employing scientific and engineering concepts to develop a threat-risk index was undertaken at the Idaho National Engineering and Environmental Laboratory (INEEL). As a result of this effort, a set of models has been successfully integrated into a single comprehensive model known as Quantitative Threat-Risk Index Model (QTRIM), with the capability of computing a quantitative threat-risk index on a system level, as well as for the major components of the system. Such a threat-risk index could provide a quantitative variant or basis for either prioritizing security upgrades or updating the current qualitative national color-coded terrorist threat alert.

  20. Quantitative evaluation of the impact of human reliability in risk assessment for nuclear power plants

    International Nuclear Information System (INIS)

    Samanta, P.K.

    1981-01-01

    The role of human beings in the safe operation of a nuclear power plant has been a matter of concern. This study describes methods for the quantitative description of that role and its impact on the risk from nuclear power plants. The impact of human errors was calculated by observing the changes in risk parameters, such as core melt probability, release category probabilities, accident sequence probabilities and system unavailabilities due to changes in the contribution to unavailablity of human errors, within the framework of risk assessment methodology. It was found that for operational pressurized water reactors the opportunity for reduction in core melt probability by reducing the human error rates without simultaneous reduction of hardware failures is limited, but that core melt probability would significantly increase as human error rates increased. More importantly, most of the dominant accident sequences showed a significant increase in their probabilities with an increase in human error rates. Release categories resulting in high consequences showed a much larger sensitivity to human errors than categories resulting in low consequences. A combination of structural importance and reliability importance measure was used to describe the importance of individual errors

  1. Integration of human reliability analysis into the probabilistic risk assessment process: phase 1

    International Nuclear Information System (INIS)

    Bell, B.J.; Vickroy, S.C.

    1985-01-01

    The US Nuclear Regulatory Commission and Pacific Northwest Laboratory initiated a research program in 1984 to develop a testable set of analytical procedures for integrating human reliability analysis (HRA) into the probabilistic risk assessment (PRA) process to more adequately assess the overall impact of human performance on risk. In this three phase program, stand-alone HRA/PRA analytic procedures will be developed and field evaluated to provide improved methods, techniques, and models for applying quantitative and qualitative human error data which systematically integrate HRA principles, techniques, and analyses throughout the entire PRA process. Phase 1 of the program involved analysis of state-of-the-art PRAs to define the structures and processes currently in use in the industry. Phase 2 research will involve developing a new or revised PRA methodology which will enable more efficient regulation of the industry using quantitative or qualitative results of the PRA. Finally, Phase 3 will be to field test those procedures to assure that the results generated by the new methodologies will be usable and acceptable to the NRC. This paper briefly describes the first phase of the program and outlines the second

  2. Integration of human reliability analysis into the probabilistic risk assessment process: Phase 1

    International Nuclear Information System (INIS)

    Bell, B.J.; Vickroy, S.C.

    1984-10-01

    A research program was initiated to develop a testable set of analytical procedures for integrating human reliability analysis (HRA) into the probabilistic risk assessment (PRA) process to more adequately assess the overall impact of human performance on risk. In this three-phase program, stand-alone HRA/PRA analytic procedures will be developed and field evaluated to provide improved methods, techniques, and models for applying quantitative and qualitative human error data which systematically integrate HRA principles, techniques, and analyses throughout the entire PRA process. Phase 1 of the program involved analysis of state-of-the-art PRAs to define the structures and processes currently in use in the industry. Phase 2 research will involve developing a new or revised PRA methodology which will enable more efficient regulation of the industry using quantitative or qualitative results of the PRA. Finally, Phase 3 will be to field test those procedures to assure that the results generated by the new methodologies will be usable and acceptable to the NRC. This paper briefly describes the first phase of the program and outlines the second

  3. External hazards in reliability and risk assessment of nuclear power plants

    International Nuclear Information System (INIS)

    Stevenson, J.D.

    1977-01-01

    It is current practice in the design of nuclear power generating stations to protect against the effects of significant natural and man-made external hazards which can occur at the plant site in excess of those hazards normally considered for conventional facilities. This paper is meant to identify those postulated external hazards typically considered in nuclear facility design. The paper also attempts to fulfill the following four objectives: (1) Define the current state of the art in applying reliability and risk analysis to determine external hazard design requirements. (2) Provide a ready source of literature references applicable to probabilistic design for extreme loads. (3) Provide some quantitative probability assessment estimates of external hazards. (4) Develop exclusion criteria by which postulated external hazards can be eliminated as a design basis. Rigorous evaluation of the design requirements for nuclear power plant facilities based on principles of probability and risk analysis is just beginning. It is hoped these techniques will be used more extensively in the future to provide a more rational basis for developing design requirements. (orig.) [de

  4. An overview of the evolution of human reliability analysis in the context of probabilistic risk assessment

    International Nuclear Information System (INIS)

    Bley, Dennis C.; Lois, Erasmia; Kolaczkowski, Alan M.; Forester, John Alan; Wreathall, John; Cooper, Susan E.

    2009-01-01

    Since the Reactor Safety Study in the early 1970's, human reliability analysis (HRA) has been evolving towards a better ability to account for the factors and conditions that can lead humans to take unsafe actions and thereby provide better estimates of the likelihood of human error for probabilistic risk assessments (PRAs). The purpose of this paper is to provide an overview of recent reviews of operational events and advances in the behavioral sciences that have impacted the evolution of HRA methods and contributed to improvements. The paper discusses the importance of human errors in complex human-technical systems, examines why humans contribute to accidents and unsafe conditions, and discusses how lessons learned over the years have changed the perspective and approach for modeling human behavior in PRAs of complicated domains such as nuclear power plants. It is argued that it has become increasingly more important to understand and model the more cognitive aspects of human performance and to address the broader range of factors that have been shown to influence human performance in complex domains. The paper concludes by addressing the current ability of HRA to adequately predict human failure events and their likelihood

  5. An overview of the evolution of human reliability analysis in the context of probabilistic risk assessment.

    Energy Technology Data Exchange (ETDEWEB)

    Bley, Dennis C. (Buttonwood Consulting Inc., Oakton, VA); Lois, Erasmia (U.S. Nuclear Regulatory Commission, Washington, DC); Kolaczkowski, Alan M. (Science Applications International Corporation, Eugene, OR); Forester, John Alan; Wreathall, John (John Wreathall and Co., Dublin, OH); Cooper, Susan E. (U.S. Nuclear Regulatory Commission, Washington, DC)

    2009-01-01

    Since the Reactor Safety Study in the early 1970's, human reliability analysis (HRA) has been evolving towards a better ability to account for the factors and conditions that can lead humans to take unsafe actions and thereby provide better estimates of the likelihood of human error for probabilistic risk assessments (PRAs). The purpose of this paper is to provide an overview of recent reviews of operational events and advances in the behavioral sciences that have impacted the evolution of HRA methods and contributed to improvements. The paper discusses the importance of human errors in complex human-technical systems, examines why humans contribute to accidents and unsafe conditions, and discusses how lessons learned over the years have changed the perspective and approach for modeling human behavior in PRAs of complicated domains such as nuclear power plants. It is argued that it has become increasingly more important to understand and model the more cognitive aspects of human performance and to address the broader range of factors that have been shown to influence human performance in complex domains. The paper concludes by addressing the current ability of HRA to adequately predict human failure events and their likelihood.

  6. Effect of standardized training on the reliability of the Cochrane risk of bias assessment tool: a study protocol.

    Science.gov (United States)

    da Costa, Bruno R; Resta, Nina M; Beckett, Brooke; Israel-Stahre, Nicholas; Diaz, Alison; Johnston, Bradley C; Egger, Matthias; Jüni, Peter; Armijo-Olivo, Susan

    2014-12-13

    The Cochrane risk of bias (RoB) tool has been widely embraced by the systematic review community, but several studies have reported that its reliability is low. We aim to investigate whether training of raters, including objective and standardized instructions on how to assess risk of bias, can improve the reliability of this tool. We describe the methods that will be used in this investigation and present an intensive standardized training package for risk of bias assessment that could be used by contributors to the Cochrane Collaboration and other reviewers. This is a pilot study. We will first perform a systematic literature review to identify randomized clinical trials (RCTs) that will be used for risk of bias assessment. Using the identified RCTs, we will then do a randomized experiment, where raters will be allocated to two different training schemes: minimal training and intensive standardized training. We will calculate the chance-corrected weighted Kappa with 95% confidence intervals to quantify within- and between-group Kappa agreement for each of the domains of the risk of bias tool. To calculate between-group Kappa agreement, we will use risk of bias assessments from pairs of raters after resolution of disagreements. Between-group Kappa agreement will quantify the agreement between the risk of bias assessment of raters in the training groups and the risk of bias assessment of experienced raters. To compare agreement of raters under different training conditions, we will calculate differences between Kappa values with 95% confidence intervals. This study will investigate whether the reliability of the risk of bias tool can be improved by training raters using standardized instructions for risk of bias assessment. One group of inexperienced raters will receive intensive training on risk of bias assessment and the other will receive minimal training. By including a control group with minimal training, we will attempt to mimic what many review authors

  7. Effect of standardized training on the reliability of the Cochrane risk of bias assessment tool: a prospective study.

    Science.gov (United States)

    da Costa, Bruno R; Beckett, Brooke; Diaz, Alison; Resta, Nina M; Johnston, Bradley C; Egger, Matthias; Jüni, Peter; Armijo-Olivo, Susan

    2017-03-03

    The Cochrane risk of bias tool is commonly criticized for having a low reliability. We aimed to investigate whether training of raters, with objective and standardized instructions on how to assess risk of bias, can improve the reliability of the Cochrane risk of bias tool. In this pilot study, four raters inexperienced in risk of bias assessment were randomly allocated to minimal or intensive standardized training for risk of bias assessment of randomized trials of physical therapy treatments for patients with knee osteoarthritis pain. Two raters were experienced risk of bias assessors who served as reference. The primary outcome of our study was between-group reliability, defined as the agreement of the risk of bias assessments of inexperienced raters with the reference assessments of experienced raters. Consensus-based assessments were used for this purpose. The secondary outcome was within-group reliability, defined as the agreement of assessments within pairs of inexperienced raters. We calculated the chance-corrected weighted Kappa to quantify agreement within and between groups of raters for each of the domains of the risk of bias tool. A total of 56 trials were included in our analysis. The Kappa for the agreement of inexperienced raters with reference across items of the risk of bias tool ranged from 0.10 to 0.81 for the minimal training group and from 0.41 to 0.90 for the standardized training group. The Kappa values for the agreement within pairs of inexperienced raters across the items of the risk of bias tool ranged from 0 to 0.38 for the minimal training group and from 0.93 to 1 for the standardized training group. Between-group differences in Kappa for the agreement of inexperienced raters with reference always favored the standardized training group and was most pronounced for incomplete outcome data (difference in Kappa 0.52, p training on risk of bias assessment may significantly improve the reliability of the Cochrane risk of bias tool.

  8. Assessments and applications to enhance human reliability and reduce risk during less-than-full-power operations

    International Nuclear Information System (INIS)

    Hannaman, G.W.; Singh, A.

    1992-01-01

    Study of events, interviews with plant personnel, and applications of risk studies indicate that the risk of a potential accident during less-than-full-power (LTFP) operation is becoming a greater fraction of the risk as improvements are made to the full-power operations. Industry efforts have been increased to reduce risk and the cost of shutdown operations. These efforts consider the development and application of advanced tools to help utilities proactively identify issues and develop contingencies and interventions to enhance reliability and reduce risk of low-power operations at nuclear power plants. The role for human reliability assessments is to help improve utility outage planning to better achieve schedule and risk control objectives. Improvements are expected to include intervention tools to identify and reduce human error, definition of new instructional modules, and prioritization of risk reduction issues for operators. The Electric Power Research Institute is sponsoring a project to address the identification and quantification of factors that affect human reliability during LTFP operation of nuclear power plants. The results of this project are expected to promote the development of proactively applied interventions and contingencies for enhanced human reliability during shutdown operations

  9. Approach to reliability assessment

    International Nuclear Information System (INIS)

    Green, A.E.; Bourne, A.J.

    1975-01-01

    Experience has shown that reliability assessments can play an important role in the early design and subsequent operation of technological systems where reliability is at a premium. The approaches to and techniques for such assessments, which have been outlined in the paper, have been successfully applied in variety of applications ranging from individual equipments to large and complex systems. The general approach involves the logical and systematic establishment of the purpose, performance requirements and reliability criteria of systems. This is followed by an appraisal of likely system achievment based on the understanding of different types of variational behavior. A fundamental reliability model emerges from the correlation between the appropriate Q and H functions for performance requirement and achievement. This model may cover the complete spectrum of performance behavior in all the system dimensions

  10. Inter-rater reliability of PATH observations for assessment of ergonomic risk factors in hospital work.

    Science.gov (United States)

    Park, Jung-Keun; Boyer, Jon; Tessler, Jamie; Casey, Jeffrey; Schemm, Linda; Gore, Rebecca; Punnett, Laura

    2009-07-01

    This study examined the inter-rater reliability of expert observations of ergonomic risk factors by four analysts. Ten jobs were observed at a hospital using a newly expanded version of the PATH method (Buchholz et al. 1996), to which selected upper extremity exposures had been added. Two of the four raters simultaneously observed each worker onsite for a total of 443 observation pairs containing 18 categorical exposure items each. For most exposure items, kappa coefficients were 0.4 or higher. For some items, agreement was higher both for the jobs with less rapid hand activity and for the analysts with a higher level of ergonomic job analysis experience. These upper extremity exposures could be characterised reliably with real-time observation, given adequate experience and training of the observers. The revised version of PATH is applicable to the analysis of jobs where upper extremity musculoskeletal strain is of concern.

  11. Probabilistic risk assessment for a loss of coolant accident in McMaster Nuclear Reactor and application of reliability physics model for modeling human reliability

    Science.gov (United States)

    Ha, Taesung

    A probabilistic risk assessment (PRA) was conducted for a loss of coolant accident, (LOCA) in the McMaster Nuclear Reactor (MNR). A level 1 PRA was completed including event sequence modeling, system modeling, and quantification. To support the quantification of the accident sequence identified, data analysis using the Bayesian method and human reliability analysis (HRA) using the accident sequence evaluation procedure (ASEP) approach were performed. Since human performance in research reactors is significantly different from that in power reactors, a time-oriented HRA model (reliability physics model) was applied for the human error probability (HEP) estimation of the core relocation. This model is based on two competing random variables: phenomenological time and performance time. The response surface and direct Monte Carlo simulation with Latin Hypercube sampling were applied for estimating the phenomenological time, whereas the performance time was obtained from interviews with operators. An appropriate probability distribution for the phenomenological time was assigned by statistical goodness-of-fit tests. The human error probability (HEP) for the core relocation was estimated from these two competing quantities: phenomenological time and operators' performance time. The sensitivity of each probability distribution in human reliability estimation was investigated. In order to quantify the uncertainty in the predicted HEPs, a Bayesian approach was selected due to its capability of incorporating uncertainties in model itself and the parameters in that model. The HEP from the current time-oriented model was compared with that from the ASEP approach. Both results were used to evaluate the sensitivity of alternative huinan reliability modeling for the manual core relocation in the LOCA risk model. This exercise demonstrated the applicability of a reliability physics model supplemented with a. Bayesian approach for modeling human reliability and its potential

  12. Structural reliability assessment capability in NESSUS

    Science.gov (United States)

    Millwater, H.; Wu, Y.-T.

    1992-07-01

    The principal capabilities of NESSUS (Numerical Evaluation of Stochastic Structures Under Stress), an advanced computer code developed for probabilistic structural response analysis, are reviewed, and its structural reliability assessed. The code combines flexible structural modeling tools with advanced probabilistic algorithms in order to compute probabilistic structural response and resistance, component reliability and risk, and system reliability and risk. An illustrative numerical example is presented.

  13. Inter-rater reliability of the German version of the Nurses' Global Assessment of Suicide Risk scale.

    Science.gov (United States)

    Kozel, Bernd; Grieser, Manuela; Abderhalden, Christoph; Cutcliffe, John R

    2016-10-01

    In comparison to the general population, the suicide rates of psychiatric inpatient populations in Germany and Switzerland are very high. An important preventive contribution to the lowering of the suicide rates in mental health care is to ensure that the risk of suicide of psychiatric inpatients is assessed as accurately as possible. While risk-assessment instruments can serve an important function in determining such risk, very few have been translated to German. Therefore, in the present study, we reported on the German version of Nurses' Global Assessment of Suicide Risk (NGASR) scale. After translating the original instrument into German and pretesting the German version, we tested the inter-rater reliability of the instrument. Twelve video case studies were evaluated by 13 raters with the NGASR scale in a 'laboratory' trial. In each case, the observer's agreement was calculated for the single items, the overall scale, the risk levels, and the sum scores. The statistical data analysis was conducted with kappa and AC1 statistics for dichotomous (items, scale) scales. A high-to-very high observers' agreement (AC1: 0.62-1.00, kappa: 0.00-1.00) was determined for 16 items of the German version of the NGASR scale. We conclude that the German version of the NGASR scale is a reliable instrument for evaluating risk factors for suicide. A reliable application in the clinical practise appears to be enhanced by training in the use of the instrument and the right implementation instructions. © 2016 Australian College of Mental Health Nurses Inc.

  14. The effect of Web-based Braden Scale training on the reliability and precision of Braden Scale pressure ulcer risk assessments.

    Science.gov (United States)

    Magnan, Morris A; Maklebust, Joann

    2008-01-01

    To evaluate the effect of Web-based Braden Scale training on the reliability and precision of pressure ulcer risk assessments made by registered nurses (RN) working in acute care settings. Pretest-posttest, 2-group, quasi-experimental design. Five hundred Braden Scale risk assessments were made on 102 acute care patients deemed to be at various levels of risk for pressure ulceration. Assessments were made by RNs working in acute care hospitals at 3 different medical centers where the Braden Scale was in regular daily use (2 medical centers) or new to the setting (1 medical center). The Braden Scale for Predicting Pressure Sore Risk was used to guide pressure ulcer risk assessments. A Web-based version of the Detroit Medical Center Braden Scale Computerized Training Module was used to teach nurses correct use of the Braden Scale and selection of risk-based pressure ulcer prevention interventions. In the aggregate, RN generated reliable Braden Scale pressure ulcer risk assessments 65% of the time after training. The effect of Web-based Braden Scale training on reliability and precision of assessments varied according to familiarity with the scale. With training, new users of the scale made reliable assessments 84% of the time and significantly improved precision of their assessments. The reliability and precision of Braden Scale risk assessments made by its regular users was unaffected by training. Technology-assisted Braden Scale training improved both reliability and precision of risk assessments made by new users of the scale, but had virtually no effect on the reliability or precision of risk assessments made by regular users of the instrument. Further research is needed to determine best approaches for improving reliability and precision of Braden Scale assessments made by its regular users.

  15. Systems reliability in high risk situations

    International Nuclear Information System (INIS)

    Hunns, D.M.

    1974-12-01

    A summary is given of five papers and the discussion of a seminar promoted by the newly-formed National Centre of Systems Reliability. The topics covered include hazard analysis, reliability assessment, and risk assessment in both nuclear and non-nuclear industries. (U.K.)

  16. Software reliability assessment

    International Nuclear Information System (INIS)

    Barnes, M.; Bradley, P.A.; Brewer, M.A.

    1994-01-01

    The increased usage and sophistication of computers applied to real time safety-related systems in the United Kingdom has spurred on the desire to provide a standard framework within which to assess dependable computing systems. Recent accidents and ensuing legislation have acted as a catalyst in this area. One particular aspect of dependable computing systems is that of software, which is usually designed to reduce risk at the system level, but which can increase risk if it is unreliable. Various organizations have recognized the problem of assessing the risk imposed to the system by unreliable software, and have taken initial steps to develop and use such assessment frameworks. This paper relates the approach of Consultancy Services of AEA Technology in developing a framework to assess the risk imposed by unreliable software. In addition, the paper discusses the experiences gained by Consultancy Services in applying the assessment framework to commercial and research projects. The framework is applicable to software used in safety applications, including proprietary software. Although the paper is written with Nuclear Reactor Safety applications in mind, the principles discussed can be applied to safety applications in all industries

  17. Risk assessment

    International Nuclear Information System (INIS)

    Kinchin, G.H.

    1983-01-01

    After defining risk and introducing the concept of individual and societal risk, the author considers each of these, restricting considerations to risk of death. Some probabilities of death arising from various causes are quoted, and attention drawn to the care necessary in making comparisons between sets of data and to the distinction between voluntary and involuntary categories and between early and delayed deaths. The presentation of information on societal risk is discussed and examples given. The history of quantified risk assessment is outlined, particularly related to the nuclear industry, the process of assessing risk discussed: identification of hazard causes, the development of accident chains and the use of event trees, the evaluation of probability through the collection of data and their use with fault trees, and the assessment of consequences of hazards in terms of fatalities. Reference is made to the human element and common-made failures, and to studies supporting the development of reliability assessment techniques. Acceptance criteria are discussed for individual and societal risk in the nuclear field, and it is shown that proposed criteria lead to risks conservative by comparison with risks from day-to-day accidents and other potentially hazardous industries. (U.K.)

  18. Influence of the human reliability in the assessment of the impact on the risk of changes of CLO

    International Nuclear Information System (INIS)

    Martorell, P.; Martorell, S.; Marton, I.; Saiz, M.

    2014-01-01

    Treatment and study of epistemic uncertainties is of special importance in the application of the analysis of probabilistic security to informed decision-making in risk, as points out the guide regulatory 1,174 [1] (Regulatory Guide 1,174, RG1.174). Specifically, the RG 1.177 [2] details of the impact on risk assessment concerning changes in the technical operating specifications (ETF). Based on the framework defined by such regulatory guides, will be assessed the effect of uncertainties epistemic associated with the analysis of human reliability in the context of the limit conditions of operation. As an example of application, will be held a sensitivity study of the time of inoperability Completion Time, the Residual heat removal system. (Author)

  19. Environmental risk assessment of biocidal products: identification of relevant components and reliability of a component-based mixture assessment.

    Science.gov (United States)

    Coors, Anja; Vollmar, Pia; Heim, Jennifer; Sacher, Frank; Kehrer, Anja

    2018-01-01

    Biocidal products are mixtures of one or more active substances (a.s.) and a broad range of formulation additives. There is regulatory guidance currently under development that will specify how the combined effects of the a.s. and any relevant formulation additives shall be considered in the environmental risk assessment of biocidal products. The default option is a component-based approach (CBA) by which the toxicity of the product is predicted from the toxicity of 'relevant' components using concentration addition. Hence, unequivocal and practicable criteria are required for identifying the 'relevant' components to ensure protectiveness of the CBA, while avoiding unnecessary workload resulting from including by default components that do not significantly contribute to the product toxicity. The present study evaluated a set of different criteria for identifying 'relevant' components using confidential information on the composition of 21 wood preservative products. Theoretical approaches were complemented by experimentally testing the aquatic toxicity of seven selected products. For three of the seven tested products, the toxicity was underestimated for the most sensitive endpoint (green algae) by more than factor 2 if only the a.s. were considered in the CBA. This illustrated the necessity of including at least some additives along with the a.s. Considering additives that were deemed 'relevant' by the tentatively established criteria reduced the underestimation of toxicity for two of the three products. A lack of data for one specific additive was identified as the most likely reason for the remaining toxicity underestimation of the third product. In three other products, toxicity was overestimated by more than factor 2, while prediction and observation fitted well for the seventh product. Considering all additives in the prediction increased only the degree of overestimation. Supported by theoretical calculations and experimental verifications, the present

  20. Probabilistic risk assessment course documentation. Volume 5. System reliability and analysis techniques Session D - quantification

    International Nuclear Information System (INIS)

    Lofgren, E.V.

    1985-08-01

    This course in System Reliability and Analysis Techniques focuses on the probabilistic quantification of accident sequences and the link between accident sequences and consequences. Other sessions in this series focus on the quantification of system reliability and the development of event trees and fault trees. This course takes the viewpoint that event tree sequences or combinations of system failures and success are available and that Boolean equations for system fault trees have been developed and are available. 93 figs., 11 tabs

  1. Reliability and availability analyses (as a basis for a simplified risk assessment) in HTR power stations

    International Nuclear Information System (INIS)

    Hinrichs

    1976-01-01

    The fault tree analysis is essentially used with HRB to investigate the failure behaviour of systems, and the characteristic reliability parameters are determined with simulation computer programmes. As the methods and auxiliary means have been given in an earlier report, only concrete studies and application examples are presented here. (RW/LH) [de

  2. 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

  3. The purpose and organisation of reliability and risk assessment studies for power plant in operation

    International Nuclear Information System (INIS)

    Ohlmeier, H.

    1989-01-01

    Upon recommendation of the Reaktorsicherheitskommission RSK, specific, probabilistic safety analyses have to be made within the next few years for every nuclear power plant in operation. The paper deals with the activities and tasks and the necessary organisational preparations to be made for carrying out the studies. A systematic determination of reliability parameters and establishment of suitable computer codes are one of the major tasks in the preparatory phase, and information for further quantification of safety reserves and more plant-specific emergency management plans will be major results of the studies. (orig.) [de

  4. Assessing the reliability, predictive and construct validity of historical, clinical and risk management-20 (HCR-20) in Mexican psychiatric inpatients.

    Science.gov (United States)

    Sada, Andrea; Robles-García, Rebeca; Martínez-López, Nicolás; Hernández-Ramírez, Rafael; Tovilla-Zarate, Carlos-Alfonso; López-Munguía, Fernando; Suárez-Alvarez, Enrique; Ayala, Xochitl; Fresán, Ana

    2016-08-01

    Assessing dangerousness to gauge the likelihood of future violent behaviour has become an integral part of clinical mental health practice in forensic and non-forensic psychiatric settings, one of the most effective instruments for this being the Historical, Clinical and Risk Management-20 (HCR-20). To examine the HCR-20 factor structure in Mexican psychiatric inpatients and to obtain its predictive validity and reliability for use in this population. In total, 225 patients diagnosed with psychotic, affective or personality disorders were included. The HCR-20 was applied at hospital admission and violent behaviours were assessed during psychiatric hospitalization using the Overt Aggression Scale (OAS). Construct validity, predictive validity and internal consistency were determined. Violent behaviour remains more severe in patients classified in the high-risk group during hospitalization. Fifteen items displayed adequate communalities in the original designated domains of the HCR-20 and internal consistency of the instruments was high. The HCR-20 is a suitable instrument for predicting violence risk in Mexican psychiatric inpatients.

  5. Risk and reliability allocation to risk control

    International Nuclear Information System (INIS)

    Vojnovic, D.; Kozuh, M.

    1992-01-01

    The risk allocation procedure is used as an analytical model to support the optimal decision making for reliability/availability improvement planning. Both levels of decision criteria, the plant risk measures and plant performance indices, are used in risk allocation procedure. Decision support system uses the multi objective decision making concept. (author) [sl

  6. OSS reliability measurement and assessment

    CERN Document Server

    Yamada, Shigeru

    2016-01-01

    This book analyses quantitative open source software (OSS) reliability assessment and its applications, focusing on three major topic areas: the Fundamentals of OSS Quality/Reliability Measurement and Assessment; the Practical Applications of OSS Reliability Modelling; and Recent Developments in OSS Reliability Modelling. Offering an ideal reference guide for graduate students and researchers in reliability for open source software (OSS) and modelling, the book introduces several methods of reliability assessment for OSS including component-oriented reliability analysis based on analytic hierarchy process (AHP), analytic network process (ANP), and non-homogeneous Poisson process (NHPP) models, the stochastic differential equation models and hazard rate models. These measurement and management technologies are essential to producing and maintaining quality/reliable systems using OSS.

  7. Operator reliability assessment system (OPERAS)

    International Nuclear Information System (INIS)

    Singh, A.; Spurgin, A.J.; Martin, T.; Welsch, J.; Hallam, J.W.

    1991-01-01

    OPERAS is a personal-computer (PC) based software to collect and process simulator data on control-room operators responses during requalification training scenarios. The data collection scheme is based upon approach developed earlier during the EPRI Operator Reliability Experiments project. The software allows automated data collection from simulator, thus minimizing simulator staff time and resources to collect, maintain and process data which can be useful in monitoring, assessing and enhancing the progress of crew reliability and effectiveness. The system is designed to provide the data and output information in the form of user-friendly charts, tables and figures for use by plant staff. OPERAS prototype software has been implemented at the Diablo Canyon (PWR) and Millstone (BWR) plants and is currently being used to collect operator response data. Data collected from similator include plant-state variables such as reactor pressure and temperature, malfunction, times at which annunciators are activated, operator actions and observations of crew behavior by training staff. The data and systematic analytical results provided by the OPERAS system can contribute to increase objectivity by the utility probabilistic risk analysis (PRA) and training staff in monitoring and assessing reliability of their crews

  8. Reliability Assessment Of Wind Turbines

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard

    2014-01-01

    Reduction of cost of energy for wind turbines are very important in order to make wind energy competitive compared to other energy sources. Therefore the turbine components should be designed to have sufficient reliability but also not be too costly (and safe). This paper presents models...... for uncertainty modeling and reliability assessment of especially the structural components such as tower, blades, substructure and foundation. But since the function of a wind turbine is highly dependent on many electrical and mechanical components as well as a control system also reliability aspects...... of these components are discussed and it is described how there reliability influences the reliability of the structural components. Two illustrative examples are presented considering uncertainty modeling, reliability assessment and calibration of partial safety factors for structural wind turbine components exposed...

  9. Methodology for allocating reliability and risk

    International Nuclear Information System (INIS)

    Cho, N.Z.; Papazoglou, I.A.; Bari, R.A.

    1986-05-01

    This report describes a methodology for reliability and risk allocation in nuclear power plants. The work investigates the technical feasibility of allocating reliability and risk, which are expressed in a set of global safety criteria and which may not necessarily be rigid, to various reactor systems, subsystems, components, operations, and structures in a consistent manner. The report also provides general discussions on the problem of reliability and risk allocation. The problem is formulated as a multiattribute decision analysis paradigm. The work mainly addresses the first two steps of a typical decision analysis, i.e., (1) identifying alternatives, and (2) generating information on outcomes of the alternatives, by performing a multiobjective optimization on a PRA model and reliability cost functions. The multiobjective optimization serves as the guiding principle to reliability and risk allocation. The concept of ''noninferiority'' is used in the multiobjective optimization problem. Finding the noninferior solution set is the main theme of the current approach. The final step of decision analysis, i.e., assessment of the decision maker's preferences could then be performed more easily on the noninferior solution set. Some results of the methodology applications to a nontrivial risk model are provided, and several outstanding issues such as generic allocation, preference assessment, and uncertainty are discussed. 29 refs., 44 figs., 39 tabs

  10. Dynamic reliability and risk assessment of the accident localization system of the Ignalina NPP RBMK-1500 reactor

    International Nuclear Information System (INIS)

    Kopustinskas, V.; Augutis, J.; Rimkevicius, S.

    2005-01-01

    The paper presents reliability and risk analysis of the RBMK-1500 reactor accident localization system (ALS) (confinement), which prevents radioactive releases to the environment. Reliability of the system was estimated and compared by two methods: the conventional fault tree method and an innovative dynamic reliability model, based on stochastic differential equations. Frequency of radioactive release through ALS was also estimated. The results of the study indicate that conventional fault tree modeling techniques in this case apply high degree of conservatism in the system reliability estimates. One of the purposes of the ALS reliability study was to demonstrate advantages of the dynamic reliability analysis against the conventional fault/event tree methods. The Markovian framework to deal with dynamic aspects of system behavior is presented. Although not analyzed in detail, the framework is also capable of accounting for non-constant component failure rates. Computational methods are proposed to solve stochastic differential equations, including analytical solution, which is possible only for relatively small and simple systems. Other numerical methods, like Monte Carlo and numerical schemes of differential equations are analyzed and compared. The study is finalized with concluding remarks regarding both the studied system reliability and computational methods used

  11. Reliability and validity of a treatment fidelity assessment for motivational interviewing targeting sexual risk behaviors in people living with HIV/AIDS.

    Science.gov (United States)

    Seng, Elizabeth K; Lovejoy, Travis I

    2013-12-01

    This study psychometrically evaluates the Motivational Interviewing Treatment Integrity Code (MITI) to assess fidelity to motivational interviewing to reduce sexual risk behaviors in people living with HIV/AIDS. 74 sessions from a pilot randomized controlled trial of motivational interviewing to reduce sexual risk behaviors in people living with HIV were coded with the MITI. Participants reported sexual behavior at baseline, 3-month, and 6-months. Regarding reliability, excellent inter-rater reliability was achieved for measures of behavior frequency across the 12 sessions coded by both coders; global scales demonstrated poor intraclass correlations, but adequate percent agreement. Regarding validity, principle components analyses indicated that a two-factor model accounted for an adequate amount of variance in the data. These factors were associated with decreases in sexual risk behaviors after treatment. The MITI is a reliable and valid measurement of treatment fidelity for motivational interviewing targeting sexual risk behaviors in people living with HIV/AIDS.

  12. Assessing the impact of uncertainty on flood risk estimates with reliability analysis using 1-D and 2-D hydraulic models

    Directory of Open Access Journals (Sweden)

    L. Altarejos-García

    2012-07-01

    Full Text Available This paper addresses the use of reliability techniques such as Rosenblueth's Point-Estimate Method (PEM as a practical alternative to more precise Monte Carlo approaches to get estimates of the mean and variance of uncertain flood parameters water depth and velocity. These parameters define the flood severity, which is a concept used for decision-making in the context of flood risk assessment. The method proposed is particularly useful when the degree of complexity of the hydraulic models makes Monte Carlo inapplicable in terms of computing time, but when a measure of the variability of these parameters is still needed. The capacity of PEM, which is a special case of numerical quadrature based on orthogonal polynomials, to evaluate the first two moments of performance functions such as the water depth and velocity is demonstrated in the case of a single river reach using a 1-D HEC-RAS model. It is shown that in some cases, using a simple variable transformation, statistical distributions of both water depth and velocity approximate the lognormal. As this distribution is fully defined by its mean and variance, PEM can be used to define the full probability distribution function of these flood parameters and so allowing for probability estimations of flood severity. Then, an application of the method to the same river reach using a 2-D Shallow Water Equations (SWE model is performed. Flood maps of mean and standard deviation of water depth and velocity are obtained, and uncertainty in the extension of flooded areas with different severity levels is assessed. It is recognized, though, that whenever application of Monte Carlo method is practically feasible, it is a preferred approach.

  13. Screening for Psychosocial Risk in Dutch Families of a Child With Cancer: Reliability, Validity, and Usability of the Psychosocial Assessment Tool

    NARCIS (Netherlands)

    Sint Nicolaas, Simone M.; Schepers, Sasja A.; Hoogerbrugge, Peter M.; Caron, Huib N.; Kaspers, Gertjan J. L.; van den Heuvel-Eibrink, Marry M.; Grootenhuis, Martha A.; Verhaak, Chris M.

    2016-01-01

    The Psychosocial Assessment Tool (PAT) was developed to screen for psychosocial risk in families of a child diagnosed with cancer. The current study is the first describing the cross-cultural adaptation, reliability, validity, and usability of the PAT in an European country (Dutch translation).   A

  14. Uses of human reliability analysis probabilistic risk assessment results to resolve personnel performance issues that could affect safety

    International Nuclear Information System (INIS)

    O'Brien, J.N.; Spettell, C.M.

    1985-10-01

    This report is the first in a series which documents research aimed at improving the usefulness of Probabilistic Risk Assessment (PRA) results in addressing human risk issues. This first report describes the results of an assessment of how well currently available PRA data addresses human risk issues of current concern to NRC. Findings indicate that PRA data could be far more useful in addressing human risk issues with modification of the development process and documentation structure of PRAs. In addition, information from non-PRA sources could be integrated with PRA data to address many other issues. 12 tabs

  15. New Approaches to Reliability Assessment

    DEFF Research Database (Denmark)

    Ma, Ke; Wang, Huai; Blaabjerg, Frede

    2016-01-01

    of energy. New approaches for reliability assessment are being taken in the design phase of power electronics systems based on the physics-of-failure in components. In this approach, many new methods, such as multidisciplinary simulation tools, strength testing of components, translation of mission profiles......, and statistical analysis, are involved to enable better prediction and design of reliability for products. This article gives an overview of the new design flow in the reliability engineering of power electronics from the system-level point of view and discusses some of the emerging needs for the technology...

  16. Risk Assessment

    Science.gov (United States)

    How the EPA conducts risk assessment to protect human health and the environment. Several assessments are included with the guidelines, models, databases, state-based RSL Tables, local contacts and framework documents used to perform these assessments.

  17. Reliability Assessment of Concrete Bridges

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle; Middleton, C. R.

    This paper is partly based on research performed for the Highways Agency, London, UK under the project DPU/9/44 "Revision of Bridge Assessment Rules Based on Whole Life Performance: concrete bridges". It contains the details of a methodology which can be used to generate Whole Life (WL) reliability...... profiles. These WL reliability profiles may be used to establish revised rules for concrete bridges. This paper is to some extend based on Thoft-Christensen et. al. [1996], Thoft-Christensen [1996] et. al. and Thoft-Christensen [1996]....

  18. Reliability assessment of Wind turbines

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard

    2015-01-01

    Wind turbines can be considered as structures that are in between civil engineering structures and machines since they consist of structural components and many electrical and machine components together with a control system. Further, a wind turbine is not a one-of-a-kind structure...... but manufactured in series production based on many component tests, some prototype tests and zeroseries wind turbines. These characteristics influence the reliability assessment where focus in this paper is on the structural components. Levelized Cost Of Energy is very important for wind energy, especially when...... comparing to other energy sources. Therefore much focus is on cost reductions and improved reliability both for offshore and onshore wind turbines. The wind turbine components should be designed to have sufficient reliability level with respect to both extreme and fatigue loads but also not be too costly...

  19. Systems Analysis Programs for Hands-on Integrated Reliability Evaluations (SAPHIRE), Version 5.0. Volume 5, Systems Analysis and Risk Assessment (SARA) tutorial manual

    International Nuclear Information System (INIS)

    Sattison, M.B.; Russell, K.D.; Skinner, N.L.

    1994-07-01

    The Systems Analysis Programs for Hands-on Integrated Reliability Evaluations (SAPHIRE) refers to a set of several microcomputer programs that were developed to create and analyze probabilistic risk assessments (PRAs) primarily for nuclear power plants. This volume is the tutorial manual for the Systems Analysis and Risk Assessment (SARA) System Version 5.0, a microcomputer-based system used to analyze the safety issues of a open-quotes familyclose quotes [i.e., a power plant, a manufacturing facility, any facility on which a probabilistic risk assessment (PRA) might be performed]. A series of lessons is provided that guides the user through some basic steps common to most analyses performed with SARA. The example problems presented in the lessons build on one another, and in combination, lead the user through all aspects of SARA sensitivity analysis capabilities

  20. The reliability and preliminary validity of game-based fall risk assessment in community-dwelling older adults.

    Science.gov (United States)

    Yamada, Minoru; Aoyama, Tomoki; Nakamura, Masatoshi; Tanaka, Buichi; Nagai, Koutatsu; Tatematsu, Noriatsu; Uemura, Kazuki; Nakamura, Takashi; Tsuboyama, Tadao; Ichihashi, Noriaki

    2011-01-01

    The purpose of this study was to examine whether the Nintendo Wii Fit program could be used for fall risk assessment in healthy, community-dwelling older adults. Forty-five community-dwelling older women participated in this study. The "Basic Step" and "Ski Slalom" modules were selected from the Wii Fit game program. The following 5 physical performance tests were performed: the 10-m walk test under single- and dual-task conditions, the Timed Up and Go test under single- and dual-task conditions, and the Functional Reach test. Compared with the faller group, the nonfaller group showed a significant difference in the Basic Step (P game-based fall risk assessment using the Basic Step has a high generality and is useful in community-dwelling older adults. Copyright © 2011 Mosby, Inc. All rights reserved.

  1. Interactive reliability assessment using an integrated reliability data bank

    International Nuclear Information System (INIS)

    Allan, R.N.; Whitehead, A.M.

    1986-01-01

    The logical structure, techniques and practical application of a computer-aided technique based on a microcomputer using floppy disc Random Access Files is described. This interactive computational technique is efficient if the reliability prediction program is coupled directly to a relevant source of data to create an integrated reliability assessment/reliability data bank system. (DG)

  2. Assessing the reliability of dose coefficients for exposure to radioiodine by members of the public, accounting for dosimetric and risk model uncertainties.

    Science.gov (United States)

    Puncher, M; Zhang, W; Harrison, J D; Wakeford, R

    2017-06-26

    Assessments of risk to a specific population group resulting from internal exposure to a particular radionuclide can be used to assess the reliability of the appropriate International Commission on Radiological Protection (ICRP) dose coefficients used as a radiation protection device for the specified exposure pathway. An estimate of the uncertainty on the associated risk is important for informing judgments on reliability; a derived uncertainty factor, UF, is an estimate of the 95% probable geometric difference between the best risk estimate and the nominal risk and is a useful tool for making this assessment. This paper describes the application of parameter uncertainty analysis to quantify uncertainties resulting from internal exposures to radioiodine by members of the public, specifically 1, 10 and 20-year old females from the population of England and Wales. Best estimates of thyroid cancer incidence risk (lifetime attributable risk) are calculated for ingestion or inhalation of 129 I and 131 I, accounting for uncertainties in biokinetic model and cancer risk model parameter values. These estimates are compared with the equivalent ICRP derived nominal age-, sex- and population-averaged estimates of excess thyroid cancer incidence to obtain UFs. Derived UF values for ingestion or inhalation of 131 I for 1 year, 10-year and 20-year olds are around 28, 12 and 6, respectively, when compared with ICRP Publication 103 nominal values, and 9, 7 and 14, respectively, when compared with ICRP Publication 60 values. Broadly similar results were obtained for 129 I. The uncertainties on risk estimates are largely determined by uncertainties on risk model parameters rather than uncertainties on biokinetic model parameters. An examination of the sensitivity of the results to the risk models and populations used in the calculations show variations in the central estimates of risk of a factor of around 2-3. It is assumed that the direct proportionality of excess thyroid cancer

  3. Failure Modes Taxonomy for Reliability Assessment of Digital Instrumentation and Control Systems for Probabilistic Risk Analysis - Failure modes taxonomy for reliability assessment of digital I and C systems for PRA

    International Nuclear Information System (INIS)

    Amri, A.; Blundell, N.; ); Authen, S.; Betancourt, L.; Coyne, K.; Halverson, D.; Li, M.; Taylor, G.; Bjoerkman, K.; Brinkman, H.; Postma, W.; Bruneliere, H.; Chirila, M.; Gheorge, R.; Chu, L.; Yue, M.; Delache, J.; Georgescu, G.; Deleuze, G.; Quatrain, R.; Thuy, N.; Holmberg, J.-E.; Kim, M.C.; Kondo, K.; Mancini, F.; Piljugin, E.; Stiller, J.; Sedlak, J.; Smidts, C.; Sopira, V.

    2015-01-01

    Digital protection and control systems appear as upgrades in older nuclear power plants (NPP), and are commonplace in new NPPs. To assess the risk of NPP operation and to determine the risk impact of digital systems, there is a need to quantitatively assess the reliability of the digital systems in a justifiable manner. Due to the many unique attributes of digital systems (e.g., functions are implemented by software, units of the system interact in a communication network, faults can be identified and handled online), a number of modelling and data collection challenges exist, and international consensus on the reliability modelling has not yet been reached. The objective of the task group called DIGREL has been to develop a taxonomy of failure modes of digital components for the purposes of probabilistic risk analysis (PRA). An activity focused on the development of a common taxonomy of failure modes is seen as an important step towards standardised digital instrumentation and control (I and C) reliability assessment techniques for PRA. Needs from PRA has guided the work, meaning, e.g., that the I and C system and its failures are studied from the point of view of their functional significance point of view. The taxonomy will be the basis of future modelling and quantification efforts. It will also help to define a structure for data collection and to review PRA studies. The proposed failure modes taxonomy has been developed by first collecting examples of taxonomies provided by the task group organisations. This material showed some variety in the handling of I and C hardware failure modes, depending on the context where the failure modes have been defined. Regarding the software part of I and C, failure modes defined in NPP PRAs have been simple - typically a software CCF failing identical processing units. The DIGREL task group has defined a new failure modes taxonomy based on a hierarchical definition of five levels of abstraction: 1. system level (complete

  4. Risk Assessment

    OpenAIRE

    Hrdová, Edita

    2012-01-01

    This diploma thesis is focused on companies risk evaluation before endorsement of Loan deriving from business relationships. The aim of this thesis is not only to describe individual steps of risk assessment, but also perfom analysis of particular companies based on available data, i.e. Balance sheet, Profit and Loss statement and external rating and after that propose solution for each company. My analysis will be based on theoretical knowledge, further on experience related to my job role a...

  5. Risk assessment

    DEFF Research Database (Denmark)

    Pedersen, Liselotte; Rasmussen, Kirsten; Elsass, Peter

    2010-01-01

    International research suggests that using formalized risk assessment methods may improve the predictive validity of professionals' predictions of risk of future violence. This study presents data on forensic psychiatric patients discharged from a forensic unit in Denmark in year 2001-2002 (n=107...... and the individual dynamic items strengthen the use of this scheme in clinical practice. (PsycINFO Database Record (c) 2010 APA, all rights reserved) (journal abstract)...

  6. 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

  7. Human reliability assessment in context

    International Nuclear Information System (INIS)

    Hollnagel, Erik

    2005-01-01

    Human Reliability Assessment (HRA) is conducted on the unspoken premise that 'human error' is a meaningful concept and that it can be associated with individual actions. The basis for this assumption it found in the origin of HRA, as a necessary extension of PSA to account for the impact of failures emanating from human actions. Although it was natural to model HRA on PSA, a large number of studies have shown that the premises are wrong, specifically that human and technological functions cannot be decomposed in the same manner. The general experience from accident studies also indicates that action failures are a function of the context, and that it is the variability of the context rather than the 'human error probability' that is the much sought for signal. Accepting this will have significant consequences for the way in which HRA, and ultimately also PSA, should be pursued

  8. Human reliability in probabilistic safety assessments

    International Nuclear Information System (INIS)

    Nunez Mendez, J.

    1989-01-01

    Nowadays a growing interest in medioambiental aspects is detected in our country. It implies an assessment of the risk involved in the industrial processess and installations in order to determine if those are into the acceptable limits. In these safety assessments, among which PSA (Probabilistic Safety Assessments), can be pointed out the role played by the human being in the system is one of the more relevant subjects. (This relevance has been demostrated in the accidents happenned). However in Spain there aren't manuals specifically dedicated to asses the human contribution to risk in the frame of PSAs. This report aims to improve this situation providing: a) a theoretical background to help the reader in the understanding of the nature of the human error, b) a guide to carry out a Human Reliability Analysis and c) a selected overwiev of the techniques and methodologies currently applied in this area. (Author)

  9. Human Reliability in Probabilistic Safety Assessments

    International Nuclear Information System (INIS)

    Nunez Mendez, J.

    1989-01-01

    Nowadays a growing interest in environmental aspects is detected in our country. It implies an assessment of the risk involved in the industrial processes and installations in order to determine if those are into the acceptable limits. In these safety assessments, among which PSA (Probabilistic Safety Assessments), can be pointed out the role played by the human being in the system is one of the more relevant subjects (This relevance has been demonstrated in the accidents happened) . However, in Spain there aren't manuals specifically dedicated to asses the human contribution to risk in the frame of PSAs. This report aims to improve this situation providing: a) a theoretical background to help the reader in the understanding of the nature of the human error, b) a quid to carry out a Human Reliability Analysis and c) a selected overview of the techniques and methodologies currently applied in this area. (Author) 20 refs

  10. ASSESSMENT OF RELIABILITY AND RISK DEGREE FOR ACCIDENT INITIATION AT SLIME STORAGES OF 4th MINING ADMINISTRATION, JSC “BELARUSKALI”

    Directory of Open Access Journals (Sweden)

    P. M. Bohaslauchyk

    2016-01-01

    Full Text Available Definition of reliability for dams of slime storage embankment is given on the basis of reliability theory and characteristics of reliability and their analysis are presented in the paper. The paper specifies qualitative indices for earth dams which are subdivided in two groups: applicability factors and structural reliability factors. A short analysis of all possible causes for accident initiation at earth dams has been made and the analysis has permitted to pinpoint eleven main objects for diagnosis for slime storage dams. In order to assess risk degree of accident initiation at JSC “Belaruskali” slime storages all possible causes of emergency cases and their probability of occurrence have been analyzed in the paper. The paper acknowledges the fact that dam malfunction is possible, as a rule, due to violation of operational rules and regulations. Main parameters of slime storage state which are to be controlled regularly in the process of its operation have been noted in the paper. Observation results over slime storages, calculations of dam slope stability for normal operation (a principal calculation case and operating irregularities in water seals (a special calculation case. As a stability margin factor is close to 1.0 for a special calculation case, an extreme position of depression curve has been determined for all design sections. It has been recommended to carry out a constant control over its position, and in the case when it reaches its peak value it is necessary to undertake appropriate measures in order to reduce its value. Final expert estimations on probability of accident initiation at the investigated slime storage dams of the 4th Mining Administration, JSC “Belaruskali” have been prepared on the basis of the analysis comprising all the required factors. A conclusion has been made about low risk degree of their destruction.

  11. Interaction of CREDO [Centralized Reliability Data Organization] with the EBR-II [Experimental Breeder Reactor II] PRA [probabilistic risk assessment] development

    International Nuclear Information System (INIS)

    Smith, M.S.; Ragland, W.A.

    1989-01-01

    The National Academy of Sciences review of US Department of Energy (DOE) class 1 reactors recommended that the Experimental Breeder Reactor II (EBR-II), operated by Argonne National Laboratory (ANL), develop a level 1 probabilistic risk assessment (PRA) and make provisions for level 2 and level 3 PRAs based on the results of the level 1 PRA. The PRA analysis group at ANL will utilize the Centralized Reliability Data Organization (CREDO) at Oak Ridge National Laboratory to support the PRA data needs. CREDO contains many years of empirical liquid-metal reactor component data from EBR-II. CREDO is a mutual data- and cost-sharing system sponsored by DOE and the Power Reactor and Nuclear Fuels Development Corporation of Japan. CREDO is a component based data system; data are collected on components that are liquid-metal specific, associated with a liquid-metal environment, contained in systems that interface with liquid-metal environments, or are safety related for use in reliability/availability/maintainability (RAM) analyses of advanced reactors. The links between the EBR-II PRA development effort and the CREDO data collection at EBR-II extend beyond the sharing of data. The PRA provides a measure of the relative contribution to risk of the various components. This information can be used to prioritize future CREDO data collection activities at EBR-II and other sites

  12. A framework for reliability and risk centered maintenance

    International Nuclear Information System (INIS)

    Selvik, J.T.; Aven, T.

    2011-01-01

    Reliability centered maintenance (RCM) is a well-established analysis method for preventive maintenance planning. As its name indicates, reliability is the main point of reference for the planning, but consequences of failures are also assessed. However, uncertainties and risk are to a limited extent addressed by the RCM method, and in this paper we suggest an extension of the RCM to reliability and risk centered maintenance (RRCM) by also considering risk as the reference for the analysis in addition to reliability. A broad perspective on risk is adopted where uncertainties are the main component of risk in addition to possible events and associated consequences. A case from the offshore oil and gas industry is presented to illustrate and discuss the suggested approach.

  13. Mercury emissions from flooded soils and sediments in Germany are an underestimated problem: challenges for reliable risk assessments and management strategies

    Directory of Open Access Journals (Sweden)

    Rinklebe J.

    2013-04-01

    Full Text Available Environmental pollution by mercury is a world-wide problem. Particularly floodplain ecosystems are frequently affected. One example is the Elbe River in Germany and its catchment areas; large amounts of Hg from a range of anthropogenic and geogenic sources have been accumulated in the soils of these floodplains. They serve as sink for Hg originating from the surface water of adjacent river. Today, the vastly elevated Hg contents of the floodplain soils at the Elbe River often exceed even the action values of the German Soil Conservation Law. This is especially important as Hg polluted areas at the Elbe River achieve several hundred square kilometres. Thus, authorities are coerced by law to conduct an appropriate risk assessment and to implement practical actions to eliminate or reduce environmental problems. A reliable risk assessment particularly with view to organisms (vegetation as green fodder and hay production, grazing and wild animals to avoid the transfer of Hg into the human food chain, requires an authentic determination of Hg fluxes and their dynamics since gaseous emissions from soil to atmosphere are an important pathway of Hg. However, reliable estimates of Hg fluxes from the highly polluted floodplain soils at the Elbe River and its tributaries, and its influencing factors are scarce. For this purpose, we have developed a new method to determine mercury emissions from soils at various sites. Our objectives were i to quantify seasonal variations of total gaseous mercury (TGM fluxes for floodplain soils at the Elbe River, ii to provide insights into physico-chemical processes regulating these TGM fluxes, and iii to quantify the impacts of the controlling factors soil temperature and soil water content on Hg volatilization from a typical contaminated floodplain soil within soil microcosm experiments under various controlled temperature and moisture conditions. Our study provides insight into TGM emissions from highly Hg

  14. 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.

  15. Usefulness and reliability of available epidemiological study results in assessments of radiation-related risks of cancer. Pt. 4

    International Nuclear Information System (INIS)

    Martignoni, K.; Elsasser, U.

    1990-05-01

    Carcinomas occurring in the thyroid gland as a result of radiation generally affect the papillary and, to a slightly lesser extent, follicular parts of this organ, while the available body of evidence hardly gives any indications of anaplastic and medullary neoplasms. Radiation has, however, mostly been associated with multicentric tumours. Among the survivors of the nuclear assaults on Hiroshima and Nagasaki, there are no known cases of anaplastic carcinomas of the thyroid. The papillary carcinoma, which is the prevailing type of neoplasm after radiation exposure, has less malignant potential than the follicular one and is encountered in all age groups. Malignant carcinomas of the thyroid are predominantly found in the middle and high age groups. It was calculated that high Gy doses and dose efficiencies are associated in children with a risk coefficient of 2.5 in 10 4 person-years. This rate is only half as high for adults. Studies performed on relevant cohorts point to latency periods of at least five years. Individuals exposed to radiation are believed to be at a forty-year or even life-long risk of developing cancer. The cancer risk can best be described on the basis of a linear dose-effect relationship. The mortality rate calculated for cancer of the thyroid amounts to approx. 10% of the morbidity rate. The carcinogenic potential of iodine-131 in the thyroid is only one-third as great as that associated with external radiation of high dose efficiency. (orig./MG) [de

  16. Value and reliability of findings from previous epidemiologic studies in the assessment of radiation-related cancer risks. Pt. 3

    International Nuclear Information System (INIS)

    Frasch, G.; Martignoni, K.

    1990-01-01

    The theories put forward here are predominantly based on pooled data from previous studies in a number of cohorts made up by mostly non-average individuals. These studies were carried out by various researchers and differed in procedures and aims. Factors of major importance to the validity and reliability of the conclusions drawn from this study are pointed out. In one chapter some light is thrown on factors known to bear a relation to the incidence of radiation-induced cancer of the breast, even though at present this can only very vaguely be described on a quantitative basis. These factors include fractionated dose regimens, pregnancies and parturitions, menarche, menopause, synergisms as well as secondary cancer of the breast. The available body of evidence suggests that exposure of each of 1 million women to a dose of 10 mGy (rad) can be linked with approx. 3 additional cases of mammary cancer reported on an average per year after the latency period. The fact that there is some statistical scatter around this value is chiefly attributable to age-related causes at the beginning of exposure. Differences in ethnic and cultural characteristics between the populations investigated appeared to be less important here. (orig./MG) [de

  17. Risk assessment

    International Nuclear Information System (INIS)

    1983-01-01

    The report is in sections, entitled: preface; summary and conclusions; introduction (historical and organizational); estimating engineering risks (techniques of risk estimation and forms of expression of risk); laboratory experiments for estimation of biological risks; estimation of risk from observations on man (travel, medical procedures; occupations; sport); the perception of risks; (as an example of attitudes towards a single hazard, studies of nuclear power are considered among other topics in this section); risk management (estimation; perception; acceptability, analysis of risk, costs and benefits; safety standards; decision-making process; possible guidelines). (U.K.)

  18. 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).

  19. Assessing the relative and absolute reliability of the Falls Efficacy Scale-International questionnaire in elderly individuals with increased fall risk and the questionnaire's convergent validity in elderly women with osteoporosis.

    Science.gov (United States)

    Halvarsson, A; Franzén, E; Ståhle, A

    2013-06-01

    The Falls Efficacy Scale-International (FES-I) is a highly reliable questionnaire for assessing fear of falling in elderly individuals with increased fall risk and has low or no convergent validity with balance performance tests and health-related quality of life (HRQL) among elderly women with osteoporosis, which indicates that both measurements should be included as they are measuring different components. Fear of falling is increased in elderly individuals with osteoporosis and FES-I is a widely used questionnaire to assess fear of falling. There is limited evidence of the reliability and convergent validity in elderly with increased risk of falling and osteoporosis. Reliability and validity study of the FES-I. Community-dwelling elderly with increased fall risk, 59 subjects, were recruited to the reliability assessment, and 81 women with osteoporosis, in the validity assessment. For the reliability assessment, two postal surveys were used. For the validity assessment, we used baseline data from an on-going study in women with osteoporosis. The FES-I was correlated to a single-item question regarding fear of falling, self-reported history of falls, balance performance tests and health-related quality of life. The FES-I had very good relative reliability (intra-class correlation 0.88) and internal consistency reliability (Cronbach's alpha 0.94). The value for absolute reliability was a standard error of measure 2.9 (10.6 %), smallest real difference 7.9 (29 %). There was "little if any" to "low" correlation between the FES-I and the single-item question regarding fear of falling and self-reported history of falls, HRQL and balance performance tests. The FES-I seems to be a highly reliable questionnaire for assessing fear of falling in elderly with increased fall risk but has low relation to/convergent validity with balance performance and HRQL among elderly women with osteoporosis.

  20. Reliability assessments in qualitative health promotion research.

    Science.gov (United States)

    Cook, Kay E

    2012-03-01

    This article contributes to the debate about the use of reliability assessments in qualitative research in general, and health promotion research in particular. In this article, I examine the use of reliability assessments in qualitative health promotion research in response to health promotion researchers' commonly held misconception that reliability assessments improve the rigor of qualitative research. All qualitative articles published in the journal Health Promotion International from 2003 to 2009 employing reliability assessments were examined. In total, 31.3% (20/64) articles employed some form of reliability assessment. The use of reliability assessments increased over the study period, ranging from qualitative articles decreased. The articles were then classified into four types of reliability assessments, including the verification of thematic codes, the use of inter-rater reliability statistics, congruence in team coding and congruence in coding across sites. The merits of each type were discussed, with the subsequent discussion focusing on the deductive nature of reliable thematic coding, the limited depth of immediately verifiable data and the usefulness of such studies to health promotion and the advancement of the qualitative paradigm.

  1. Parts and Components Reliability Assessment: A Cost Effective Approach

    Science.gov (United States)

    Lee, Lydia

    2009-01-01

    System reliability assessment is a methodology which incorporates reliability analyses performed at parts and components level such as Reliability Prediction, Failure Modes and Effects Analysis (FMEA) and Fault Tree Analysis (FTA) to assess risks, perform design tradeoffs, and therefore, to ensure effective productivity and/or mission success. The system reliability is used to optimize the product design to accommodate today?s mandated budget, manpower, and schedule constraints. Stand ard based reliability assessment is an effective approach consisting of reliability predictions together with other reliability analyses for electronic, electrical, and electro-mechanical (EEE) complex parts and components of large systems based on failure rate estimates published by the United States (U.S.) military or commercial standards and handbooks. Many of these standards are globally accepted and recognized. The reliability assessment is especially useful during the initial stages when the system design is still in the development and hard failure data is not yet available or manufacturers are not contractually obliged by their customers to publish the reliability estimates/predictions for their parts and components. This paper presents a methodology to assess system reliability using parts and components reliability estimates to ensure effective productivity and/or mission success in an efficient manner, low cost, and tight schedule.

  2. 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

  3. Operator reliability assessment system (OPERAS)

    International Nuclear Information System (INIS)

    Spurgin, A.J.; Hallam, J.W.; Spurgin, J.P.; Singh, A.

    1991-01-01

    The paper gives an overview of the OPERAS project. It discusses the background which led to the design of the PC-based data collection and analysis system connected to plant training simulators including those used for nuclear power plants. The usefulness of a system like OPERAS was perceived during an earlier EPRI project, the Operator Reliability Experiments project, by EPRI and PG and E. The data collection and analysis approaches used in OPERAS were developed during the ORE project. The paper not only discusses the design of OPERAS but discusses the functions performed and the current experiences with the two prototype systems. Also listed are potential uses of OPERAS by utility personnel in Operations, Training and PRA groups

  4. Introduction to risk assessment

    International Nuclear Information System (INIS)

    Raina, V.M.

    2002-01-01

    This paper gives an introduction to risk assessment. It discusses the basic concepts of risk assessment, nuclear risk assessment process and products, the role of risk assessment products in nuclear safety assurance, the relationship between risk assessment and other safety analysis and risk assessment and safe operating envelope

  5. Challenges in Risk Assessment: Quantitative Risk Assessment

    OpenAIRE

    Jacxsens, Liesbeth; Uyttendaele, Mieke; De Meulenaer, Bruno

    2016-01-01

    The process of risk analysis consists out of three components, risk assessment, risk management and risk communication. These components are internationally well spread by Codex Alimentarius Commission as being the basis for setting science based standards, criteria on food safety hazards, e.g. setting maximum limits of mycotoxins in foodstuffs. However, the technical component risk assessment is hard to elaborate and to understand. Key in a risk assessment is the translation of biological or...

  6. Reliability of blood pressure measurement and cardiovascular risk prediction

    NARCIS (Netherlands)

    van der Hoeven, N.V.

    2016-01-01

    High blood pressure is one of the leading risk factors for cardiovascular disease, but difficult to reliably assess because there are many factors which can influence blood pressure including stress, exercise or illness. The first part of this thesis focuses on possible ways to improve the

  7. Assessing the reliability of skilled performance

    International Nuclear Information System (INIS)

    Dougherty, E.M.; Collins, E.P.

    1996-01-01

    In some high-hazard military tasks, precision of motor skills is crucial to avoid a risk-sensitive drop or other mishap. Sparse data supports a basic level of reliability for this activity seemingly much lower than typical, individual action, slip-mode errors would yield. A typical occurrence failure rate seems to be of the order of 1 x 10 -5 per opportunity. A speculation is tendered that this represents a difference in kind; that the reliability of skills is a different taxon than previously called out in the typical scheme of human reliability

  8. An approach for assessing human decision reliability

    International Nuclear Information System (INIS)

    Pyy, P.

    2000-01-01

    This paper presents a method to study human reliability in decision situations related to nuclear power plant disturbances. Decisions often play a significant role in handling of emergency situations. The method may be applied to probabilistic safety assessments (PSAs) in cases where decision making is an important dimension of an accident sequence. Such situations are frequent e.g. in accident management. In this paper, a modelling approach for decision reliability studies is first proposed. Then, a case study with two decision situations with relatively different characteristics is presented. Qualitative and quantitative findings of the study are discussed. In very simple decision cases with time pressure, time reliability correlation proved out to be a feasible reliability modelling method. In all other decision situations, more advanced probabilistic decision models have to be used. Finally, decision probability assessment by using simulator run results and expert judgement is presented

  9. Assessing reliability in energy supply systems

    International Nuclear Information System (INIS)

    McCarthy, Ryan W.; Ogden, Joan M.; Sperling, Daniel

    2007-01-01

    Reliability has always been a concern in the energy sector, but concerns are escalating as energy demand increases and the political stability of many energy supply regions becomes more questionable. But how does one define and measure reliability? We introduce a method to assess reliability in energy supply systems in terms of adequacy and security. It derives from reliability assessment frameworks developed for the electricity sector, which are extended to include qualitative considerations and to be applicable to new energy systems by incorporating decision-making processes based on expert opinion and multi-attribute utility theory. The method presented here is flexible and can be applied to any energy system. To illustrate its use, we apply the method to two hydrogen pathways: (1) centralized steam reforming of imported liquefied natural gas with pipeline distribution of hydrogen, and (2) on-site electrolysis of water using renewable electricity produced independently from the electricity grid

  10. Reliability assessment based on subjective inferences

    International Nuclear Information System (INIS)

    Ma Zhibo; Zhu Jianshi; Xu Naixin

    2003-01-01

    The reliability information which comes from subjective analysis is often incomplete prior. This information can be generally assumed to exist in the form of either a stated prior mean of R (reliability) or a stated prior credibility interval on R. An efficient approach is developed to determine a complete beta prior distribution from the subjective information according to the principle of maximum entropy, and the the reliability of survival/failure product is assessed via Bayes theorem. Numerical examples are presented to illustrate the methods

  11. Human reliability. Is probabilistic human reliability assessment possible?

    International Nuclear Information System (INIS)

    Mosneron Dupin, F.

    1996-01-01

    The possibility of carrying out Probabilistic Human Reliability Assessments (PHRA) is often doubted. Basing ourselves on the experience Electricite de France (EDF) has acquired in Probabilistic Safety Assessments for nuclear power plants, we show why the uncertainty of PHRA is very high. We then specify the limits of generic data and models for PHRA: very important factors are often poorly taken into account. To account for them, you need to have proper understanding of the actual context in which operators work. This demands surveys on the field (power plant and simulator) all of which must be carried out with behaviours science skills. The idea of estimating the probabilities of operator failure must not be abandoned, but probabilities must be given less importance, for they are only approximate indications. The qualitative aspects of PHRA should be given greater value (analysis process and qualitative insights). That is why the description (illustrated by case histories) of the main mechanisms of human behaviour, and of their manifestations in the nuclear power plant context (in terms of habits, attitudes, and informal methods and organization in particular) should be an important part of PHRA handbooks. These handbooks should also insist more on methods for gathering information on the actual context of the work of operators. Under these conditions, the PHRA should be possible and even desirable as a process for systematic analysis and assessment of human intervention. (author). 24 refs, 2 figs, 1 tab

  12. Human reliability. Is probabilistic human reliability assessment possible?

    Energy Technology Data Exchange (ETDEWEB)

    Mosneron Dupin, F

    1997-12-31

    The possibility of carrying out Probabilistic Human Reliability Assessments (PHRA) is often doubted. Basing ourselves on the experience Electricite de France (EDF) has acquired in Probabilistic Safety Assessments for nuclear power plants, we show why the uncertainty of PHRA is very high. We then specify the limits of generic data and models for PHRA: very important factors are often poorly taken into account. To account for them, you need to have proper understanding of the actual context in which operators work. This demands surveys on the field (power plant and simulator) all of which must be carried out with behaviours science skills. The idea of estimating the probabilities of operator failure must not be abandoned, but probabilities must be given less importance, for they are only approximate indications. The qualitative aspects of PHRA should be given greater value (analysis process and qualitative insights). That is why the description (illustrated by case histories) of the main mechanisms of human behaviour, and of their manifestations in the nuclear power plant context (in terms of habits, attitudes, and informal methods and organization in particular) should be an important part of PHRA handbooks. These handbooks should also insist more on methods for gathering information on the actual context of the work of operators. Under these conditions, the PHRA should be possible and even desirable as a process for systematic analysis and assessment of human intervention. (author). 24 refs, 2 figs, 1 tab.

  13. Reliability and risk treatment centered maintenance

    International Nuclear Information System (INIS)

    Pexa, Martin; Hladik, Tomas; Ales, Zdenek; Legat, Vaclav; Muller, Miroslav; Valasek, Petr; Havlu, Vit

    2014-01-01

    We propose a new methodology for application of well-known tools - RCM, RBI and SIF pro - with the aim to treat risks by means of suitable maintenance. The basis of the new methodology is the complex application of all three methods at the same time and not separately as is typical today. The proposed methodology suggests having just one managing team for reliability and risk treatment centred maintenance (RRTCM), employing existing RCM, RBI, and SIFpro tools concurrently. This approach allows for significant reduction of engineering activities' duration. In the proposed methodology these activities are staged into five phases and structured to eliminate all duplication resulting from separate application of the three tools. The newly proposed methodology saves 45% to 50% of the engineering workload and dequate significant financial savings.

  14. Reliability and risk treatment centered maintenance

    Energy Technology Data Exchange (ETDEWEB)

    Pexa, Martin; Hladik, Tomas; Ales, Zdenek; Legat, Vaclav; Muller, Miroslav; Valasek, Petr [Czech University of Life Sciences Prague, Kamycka (Czech Republic); Havlu, Vit [Unipetrol A. S, Prague (Czech Republic)

    2014-10-15

    We propose a new methodology for application of well-known tools - RCM, RBI and SIF pro - with the aim to treat risks by means of suitable maintenance. The basis of the new methodology is the complex application of all three methods at the same time and not separately as is typical today. The proposed methodology suggests having just one managing team for reliability and risk treatment centred maintenance (RRTCM), employing existing RCM, RBI, and SIFpro tools concurrently. This approach allows for significant reduction of engineering activities' duration. In the proposed methodology these activities are staged into five phases and structured to eliminate all duplication resulting from separate application of the three tools. The newly proposed methodology saves 45% to 50% of the engineering workload and dequate significant financial savings.

  15. MRI as a reliable and accurate method for assessment of posterior hip dislocation in children and adolescents without the risk of radiation exposure

    Energy Technology Data Exchange (ETDEWEB)

    Mayer, Stephanie W.; Kestel, Lauryn; Novais, Eduardo N. [Children' s Hospital Colorado and University of Colorado School of Medicine, Department of Orthopaedic Surgery, Aurora, CO (United States); Stewart, Jaime R.; Fadell, Michael F. [Children' s Hospital Colorado, University of Colorado School of Medicine, Department of Radiology, Aurora, CO (United States)

    2015-08-15

    open surgical treatment were universally recognized on MRI but not on CT scans. MRI should be considered for evaluation of the hip following closed reduction for the treatment of a posterior dislocation in children and adolescents as it reliably allows assessment of intra-articular pathology without the risk of radiation exposure. (orig.)

  16. Predicting risk and human reliability: a new approach

    International Nuclear Information System (INIS)

    Duffey, R.; Ha, T.-S.

    2009-01-01

    Learning from experience describes human reliability and skill acquisition, and the resulting theory has been validated by comparison against millions of outcome data from multiple industries and technologies worldwide. The resulting predictions were used to benchmark the classic first generation human reliability methods adopted in probabilistic risk assessments. The learning rate, probabilities and response times are also consistent with the existing psychological models for human learning and error correction. The new approach also implies a finite lower bound probability that is not predicted by empirical statistical distributions that ignore the known and fundamental learning effects. (author)

  17. The Reliability and Predictive Validity of the Stalking Risk Profile.

    Science.gov (United States)

    McEwan, Troy E; Shea, Daniel E; Daffern, Michael; MacKenzie, Rachel D; Ogloff, James R P; Mullen, Paul E

    2018-03-01

    This study assessed the reliability and validity of the Stalking Risk Profile (SRP), a structured measure for assessing stalking risks. The SRP was administered at the point of assessment or retrospectively from file review for 241 adult stalkers (91% male) referred to a community-based forensic mental health service. Interrater reliability was high for stalker type, and moderate-to-substantial for risk judgments and domain scores. Evidence for predictive validity and discrimination between stalking recidivists and nonrecidivists for risk judgments depended on follow-up duration. Discrimination was moderate (area under the curve = 0.66-0.68) and positive and negative predictive values good over the full follow-up period ( Mdn = 170.43 weeks). At 6 months, discrimination was better than chance only for judgments related to stalking of new victims (area under the curve = 0.75); however, high-risk stalkers still reoffended against their original victim(s) 2 to 4 times as often as low-risk stalkers. Implications for the clinical utility and refinement of the SRP are discussed.

  18. Procedures for controlling the risks of reliability, safety, and availability of technical systems

    International Nuclear Information System (INIS)

    1987-01-01

    The reference book covers four sections. Apart from the fundamental aspects of the reliability problem, of risk and safety and the relevant criteria with regard to reliability, the material presented explains reliability in terms of maintenance, logistics and availability, and presents procedures for reliability assessment and determination of factors influencing the reliability, together with suggestions for systems technical integration. The reliability assessment consists of diagnostic and prognostic analyses. The section on factors influencing reliability discusses aspects of organisational structures, programme planning and control, and critical activities. (DG) [de

  19. Hepatitis Risk Assessment

    Science.gov (United States)

    ... please visit this page: About CDC.gov . Hepatitis Risk Assessment Recommend on Facebook Tweet Share Compartir Viral Hepatitis. Are you at risk? Take this 5 minute Hepatitis Risk Assessment developed ...

  20. Automated reliability assessment for spectroscopic redshift measurements

    Science.gov (United States)

    Jamal, S.; Le Brun, V.; Le Fèvre, O.; Vibert, D.; Schmitt, A.; Surace, C.; Copin, Y.; Garilli, B.; Moresco, M.; Pozzetti, L.

    2018-03-01

    Context. Future large-scale surveys, such as the ESA Euclid mission, will produce a large set of galaxy redshifts (≥106) that will require fully automated data-processing pipelines to analyze the data, extract crucial information and ensure that all requirements are met. A fundamental element in these pipelines is to associate to each galaxy redshift measurement a quality, or reliability, estimate. Aim. In this work, we introduce a new approach to automate the spectroscopic redshift reliability assessment based on machine learning (ML) and characteristics of the redshift probability density function. Methods: We propose to rephrase the spectroscopic redshift estimation into a Bayesian framework, in order to incorporate all sources of information and uncertainties related to the redshift estimation process and produce a redshift posterior probability density function (PDF). To automate the assessment of a reliability flag, we exploit key features in the redshift posterior PDF and machine learning algorithms. Results: As a working example, public data from the VIMOS VLT Deep Survey is exploited to present and test this new methodology. We first tried to reproduce the existing reliability flags using supervised classification in order to describe different types of redshift PDFs, but due to the subjective definition of these flags (classification accuracy 58%), we soon opted for a new homogeneous partitioning of the data into distinct clusters via unsupervised classification. After assessing the accuracy of the new clusters via resubstitution and test predictions (classification accuracy 98%), we projected unlabeled data from preliminary mock simulations for the Euclid space mission into this mapping to predict their redshift reliability labels. Conclusions: Through the development of a methodology in which a system can build its own experience to assess the quality of a parameter, we are able to set a preliminary basis of an automated reliability assessment for

  1. Assessment of the Reliability of Concrete Bridges

    DEFF Research Database (Denmark)

    Middleton, C. R.; Thoft-Christensen, Palle

    Although there has been a considerable amount of research into different aspects of concrete bridge reliability, it has still not been widely adopted in professional practice other than in the development and calibration of codes. This situation appears to be changing as there has been a signific......Although there has been a considerable amount of research into different aspects of concrete bridge reliability, it has still not been widely adopted in professional practice other than in the development and calibration of codes. This situation appears to be changing as there has been...... adopted to assist in achieving this goal. Rather than review the specific research on this subject this paper examines a number of key issues related to the practical application of reliability analysis to the assessment of concrete bridges....

  2. Quantified Risk Ranking Model for Condition-Based Risk and Reliability Centered Maintenance

    Science.gov (United States)

    Chattopadhyaya, Pradip Kumar; Basu, Sushil Kumar; Majumdar, Manik Chandra

    2017-06-01

    In the recent past, risk and reliability centered maintenance (RRCM) framework is introduced with a shift in the methodological focus from reliability and probabilities (expected values) to reliability, uncertainty and risk. In this paper authors explain a novel methodology for risk quantification and ranking the critical items for prioritizing the maintenance actions on the basis of condition-based risk and reliability centered maintenance (CBRRCM). The critical items are identified through criticality analysis of RPN values of items of a system and the maintenance significant precipitating factors (MSPF) of items are evaluated. The criticality of risk is assessed using three risk coefficients. The likelihood risk coefficient treats the probability as a fuzzy number. The abstract risk coefficient deduces risk influenced by uncertainty, sensitivity besides other factors. The third risk coefficient is called hazardous risk coefficient, which is due to anticipated hazards which may occur in the future and the risk is deduced from criteria of consequences on safety, environment, maintenance and economic risks with corresponding cost for consequences. The characteristic values of all the three risk coefficients are obtained with a particular test. With few more tests on the system, the values may change significantly within controlling range of each coefficient, hence `random number simulation' is resorted to obtain one distinctive value for each coefficient. The risk coefficients are statistically added to obtain final risk coefficient of each critical item and then the final rankings of critical items are estimated. The prioritization in ranking of critical items using the developed mathematical model for risk assessment shall be useful in optimization of financial losses and timing of maintenance actions.

  3. 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

  4. Complex method to calculate objective assessments of information systems protection to improve expert assessments reliability

    Science.gov (United States)

    Abdenov, A. Zh; Trushin, V. A.; Abdenova, G. A.

    2018-01-01

    The paper considers the questions of filling the relevant SIEM nodes based on calculations of objective assessments in order to improve the reliability of subjective expert assessments. The proposed methodology is necessary for the most accurate security risk assessment of information systems. This technique is also intended for the purpose of establishing real-time operational information protection in the enterprise information systems. Risk calculations are based on objective estimates of the adverse events implementation probabilities, predictions of the damage magnitude from information security violations. Calculations of objective assessments are necessary to increase the reliability of the proposed expert assessments.

  5. 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.

  6. Sequential decision reliability concept and failure rate assessment

    International Nuclear Information System (INIS)

    Ciftcioglu, O.

    1990-11-01

    Conventionally, a reliability concept is considered together with both each basic unit and their integration in a complicated large scale system such as a nuclear power plant (NPP). Basically, as the plant's operational status is determined by the information obtained from various sensors, the plant's reliability and the risk assessment is closely related to the reliability of the sensory information and hence the sensor components. However, considering the relevant information-processing systems, e.g. fault detection processors, there exists a further question about the reliability of such systems, specifically the reliability of the systems' decision-based outcomes by means of which the further actions are performed. To this end, a general sequential decision reliability concept and the failure rate assessment methodology is introduced. The implications of the methodology are investigated and the importance of the decision reliability concept in system operation is demonstrated by means of sensory signals in real-time from the Borssele NPP in the Netherlands. (author). 21 refs.; 8 figs

  7. Dutch Risk Assessment tools

    NARCIS (Netherlands)

    Venema, A.

    2015-01-01

    The ‘Risico- Inventarisatie- en Evaluatie-instrumenten’ is the name for the Dutch risk assessment (RA) tools. A RA tool can be used to perform a risk assessment including an evaluation of the identified risks. These tools were among the first online risk assessment tools developed in Europe. The

  8. Deterministic quantitative risk assessment development

    Energy Technology Data Exchange (ETDEWEB)

    Dawson, Jane; Colquhoun, Iain [PII Pipeline Solutions Business of GE Oil and Gas, Cramlington Northumberland (United Kingdom)

    2009-07-01

    Current risk assessment practice in pipeline integrity management is to use a semi-quantitative index-based or model based methodology. This approach has been found to be very flexible and provide useful results for identifying high risk areas and for prioritizing physical integrity assessments. However, as pipeline operators progressively adopt an operating strategy of continual risk reduction with a view to minimizing total expenditures within safety, environmental, and reliability constraints, the need for quantitative assessments of risk levels is becoming evident. Whereas reliability based quantitative risk assessments can be and are routinely carried out on a site-specific basis, they require significant amounts of quantitative data for the results to be meaningful. This need for detailed and reliable data tends to make these methods unwieldy for system-wide risk k assessment applications. This paper describes methods for estimating risk quantitatively through the calibration of semi-quantitative estimates to failure rates for peer pipeline systems. The methods involve the analysis of the failure rate distribution, and techniques for mapping the rate to the distribution of likelihoods available from currently available semi-quantitative programs. By applying point value probabilities to the failure rates, deterministic quantitative risk assessment (QRA) provides greater rigor and objectivity than can usually be achieved through the implementation of semi-quantitative risk assessment results. The method permits a fully quantitative approach or a mixture of QRA and semi-QRA to suit the operator's data availability and quality, and analysis needs. For example, consequence analysis can be quantitative or can address qualitative ranges for consequence categories. Likewise, failure likelihoods can be output as classical probabilities or as expected failure frequencies as required. (author)

  9. Methodology for reliability based condition assessment

    International Nuclear Information System (INIS)

    Mori, Y.; Ellingwood, B.

    1993-08-01

    Structures in nuclear power plants may be exposed to aggressive environmental effects that cause their strength to decrease over an extended period of service. A major concern in evaluating the continued service for such structures is to ensure that in their current condition they are able to withstand future extreme load events during the intended service life with a level of reliability sufficient for public safety. This report describes a methodology to facilitate quantitative assessments of current and future structural reliability and performance of structures in nuclear power plants. This methodology takes into account the nature of past and future loads, and randomness in strength and in degradation resulting from environmental factors. An adaptive Monte Carlo simulation procedure is used to evaluate time-dependent system reliability. The time-dependent reliability is sensitive to the time-varying load characteristics and to the choice of initial strength and strength degradation models but not to correlation in component strengths within a system. Inspection/maintenance strategies are identified that minimize the expected future costs of keeping the failure probability of a structure at or below an established target failure probability during its anticipated service period

  10. Operational human performance reliability assessment (OHPRA)

    International Nuclear Information System (INIS)

    Haas, P.M.; Swanson, P.J.; Connelly, E.M.

    1993-01-01

    Operational Human Performance Reliability Assessment (OHPRA) is an approach for assessing human performance that is being developed in response to demands from modern process industries for practical and effective tools to assess and improve human performance, and therefore overall system performance and safety. The single most distinguishing feature of the approach is that is defines human performance in open-quotes operationalclose quotes terms. OHPRA is focused not on generation of human error probabilities, but on practical analysis of human performance to aid management in (1) identifying open-quotes fixableclose quotes problems and (2) providing input on the importance and nature of potential improvements. Development of the model in progress uses a unique approach for eliciting expert strategies for assessing performance. A PC-based model incorporating this expertise is planned. A preliminary version of the approach has already been used successfully to identify practical human performance problems in reactor and chemical process plant operations

  11. Reliability assessment of nuclear structural systems

    International Nuclear Information System (INIS)

    Reich, M.; Hwang, H.

    1983-01-01

    Reliability assessment of nuclear structural systems has been receiving more emphasis over the last few years. This paper deals with the recent progress made by the Structural Analysis Division of Brookhaven National Laboratory (BNL), in the development of a probability-based reliability analysis methodology for safety evaluation of reactor containments and other seismic category I structures. An important feature of this methodology is the incorporation of finite element analysis and random vibration theory. By utilizing this method, it is possible to evaluate the safety of nuclear structures under various static and dynamic loads in terms of limit state probability. Progress in other related areas, such as the establishment of probabilistic characteristics for various loads and structural resistance, are also described. Results of an application of the methodology to a realistic reinforced concrete containment subjected to dead and live loads, accidental internal pressures and earthquake ground accelerations are presented

  12. Student Precision and Reliability of the Team Sport Assessment in ...

    African Journals Online (AJOL)

    TSAP) and formative assessment of invasion sport. The specific objectives were to determine the degree of agreement among expert observers, inter-observer reliability (internal consistency), and intra observer reliability (temporal reliability).

  13. Commentary: Risk Management and Reliability Design for Buildings

    Energy Technology Data Exchange (ETDEWEB)

    Berry, Dennis L.; Cranwell, Robert M.; Hunter, Regina L.

    1999-05-28

    Where there is a significant actuarial basis for decision making (e.g., the occurrence of fires in single-family dwellings), there is little incentive for formal risk management. Formal risk assessments are most useful in those cases where the value of the structure is high, many people may be affected, the societal perception of risk is high, consequences of a mishap would be severe, and the actuarial uncertainty is large. For these cases, there is little opportunity to obtain the necessary experiential data to make informed decisions, and the consequences in terms of money, lives, and societal confidence are severe enough to warrant a formal risk assessment. Other important factors include the symbolic value of the structure and vulnerability to single point failures. It is unlikely that formal risk management and assessment practices will or should replace the proven institutions of building codes and engineering practices. Nevertheless, formal risk assessment can provide valuable insights into the hazards threatening high-value and high-risk (perceived or actual) buildings and structures, which can in turn be translated into improved public health, safety, and security. The key is to choose and apply the right assessment tool to match the structure in question. Design-for-reliability concepts can be applied to buildings, bridges, transportation sys- tems, dams, and other structures. The use of these concepts could have the dual benefits of lowering life-cycle costs by reducing the necessity for maintenance and repair and of enhancing the saiiety and security of the structure's users.

  14. Dynamical systems probabilistic risk assessment

    Energy Technology Data Exchange (ETDEWEB)

    Denman, Matthew R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Ames, Arlo Leroy [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2014-03-01

    Probabilistic Risk Assessment (PRA) is the primary tool used to risk-inform nuclear power regulatory and licensing activities. Risk-informed regulations are intended to reduce inherent conservatism in regulatory metrics (e.g., allowable operating conditions and technical specifications) which are built into the regulatory framework by quantifying both the total risk profile as well as the change in the risk profile caused by an event or action (e.g., in-service inspection procedures or power uprates). Dynamical Systems (DS) analysis has been used to understand unintended time-dependent feedbacks in both industrial and organizational settings. In dynamical systems analysis, feedback loops can be characterized and studied as a function of time to describe the changes to the reliability of plant Structures, Systems and Components (SSCs). While DS has been used in many subject areas, some even within the PRA community, it has not been applied toward creating long-time horizon, dynamic PRAs (with time scales ranging between days and decades depending upon the analysis). Understanding slowly developing dynamic effects, such as wear-out, on SSC reliabilities may be instrumental in ensuring a safely and reliably operating nuclear fleet. Improving the estimation of a plant's continuously changing risk profile will allow for more meaningful risk insights, greater stakeholder confidence in risk insights, and increased operational flexibility.

  15. Assessment of cardiovascular risk.

    LENUS (Irish Health Repository)

    Cooney, Marie Therese

    2010-10-01

    Atherosclerotic cardiovascular disease (CVD) is the most common cause of death worldwide. Usually atherosclerosis is caused by the combined effects of multiple risk factors. For this reason, most guidelines on the prevention of CVD stress the assessment of total CVD risk. The most intensive risk factor modification can then be directed towards the individuals who will derive the greatest benefit. To assist the clinician in calculating the effects of these multiple interacting risk factors, a number of risk estimation systems have been developed. This review address several issues regarding total CVD risk assessment: Why should total CVD risk be assessed? What risk estimation systems are available? How well do these systems estimate risk? What are the advantages and disadvantages of the current systems? What are the current limitations of risk estimation systems and how can they be resolved? What new developments have occurred in CVD risk estimation?

  16. An approach for assessing ALWR passive safety system reliability

    International Nuclear Information System (INIS)

    Hake, T.M.

    1991-01-01

    Many of the advanced light water reactor (ALWR) concepts proposed for the next generation of nuclear power plants rely on passive rather than active systems to perform safety functions. Despite the reduced redundancy of the passive systems as compared to active systems in current plants, the assertion is that the overall safety of the plant is enhanced due to the much higher expected reliability of the passive systems. In order to investigate this assertion, a study is being conducted at Sandia National Laboratories to evaluate the reliability of ALWR passive safety features in the context of probabilistic risk assessment (PRA). The purpose of this paper is to provide a brief overview of the approach to this study. The quantification of passive system reliability is not as straightforward as for active systems, due to the lack of operating experience, and to the greater uncertainty in the governing physical phenomena. Thus, the adequacy of current methods for evaluating system reliability must be assessed, and alternatives proposed if necessary. For this study, the Westinghouse Advanced Passive 600 MWe reactor (AP600) was chosen as the advanced reactor for analysis, because of the availability of AP600 design information. This study compares the reliability of AP600 emergency cooling system with that of corresponding systems in a current generation reactor

  17. Assessment of physical server reliability in multi cloud computing system

    Science.gov (United States)

    Kalyani, B. J. D.; Rao, Kolasani Ramchand H.

    2018-04-01

    Business organizations nowadays functioning with more than one cloud provider. By spreading cloud deployment across multiple service providers, it creates space for competitive prices that minimize the burden on enterprises spending budget. To assess the software reliability of multi cloud application layered software reliability assessment paradigm is considered with three levels of abstractions application layer, virtualization layer, and server layer. The reliability of each layer is assessed separately and is combined to get the reliability of multi-cloud computing application. In this paper, we focused on how to assess the reliability of server layer with required algorithms and explore the steps in the assessment of server reliability.

  18. GM Risk Assessment

    Science.gov (United States)

    Sparrow, Penny A. C.

    GM risk assessments play an important role in the decision-making process surrounding the regulation, notification and permission to handle Genetically Modified Organisms (GMOs). Ultimately the role of a GM risk assessment will be to ensure the safe handling and containment of the GMO; and to assess any potential impacts on the environment and human health. A risk assessment should answer all ‘what if’ scenarios, based on scientific evidence.

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

    Science.gov (United States)

    Garcia-Hernandez, Alberto

    2015-11-01

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

  20. Risk and reliability analyses (LURI) and expert judgement techniques

    International Nuclear Information System (INIS)

    Pyy, P.; Pulkkinen, U.

    1998-01-01

    Probabilistic safety analysis (PSA) is currently used as a regulatory licensing tool in risk informed and plant performance based regulation. More often also utility safety improvements are based on PSA calculations as one criterion. PSA attempts to comprehensively identify all important risk contributors, compare them with each other, assess the safety level and suggest improvements based on its findings. The strength of PSA is that it is capable to provide decision makers with numerical estimates of risks. This makes decision making easier than the comparison of purely qualitative results. PSA is the only comprehensive tool that compactly attempts to include all the important risk contributors in its scope. Despite the demonstrated strengths of PSA, there are some features that have reduced its uses. For example, the PSA scope has been limited to the power operation and process internal events (transients and LOCAs). Only lately, areas such as shutdown, external events and severe accidents have been included in PSA models in many countries. Problems related to modelling are, e.g., that rather static fault and event tree models are commonly used in PSA to model dynamic event sequences. Even if a valid model may be generated, there may not be any other data sources to be used than expert judgement. Furthermore, there are a variety of different techniques for human reliability assessment (HRA) giving varying results. In the project Reliability and Risk Analyses (LURI) these limitations and shortcomings have been studied. In the decision making area, case studies on the application of decision analysis and a doctoral thesis have been published. Further, practical aid has been given to utilities and regulatory decision making. Model uncertainty effect on PSA results has been demonstrated by two case studies. Human reliability has been studied both in the integrated safety analysis study and in the study of maintenance originated NPP component faults based on the

  1. Strategic Risk Assessment

    Science.gov (United States)

    Derleth, Jason; Lobia, Marcus

    2009-01-01

    This slide presentation provides an overview of the attempt to develop and demonstrate a methodology for the comparative assessment of risks across the entire portfolio of NASA projects and assets. It includes information about strategic risk identification, normalizing strategic risks, calculation of relative risk score, and implementation options.

  2. Building Better Environmental Risk Assessments

    Science.gov (United States)

    Layton, Raymond; Smith, Joe; Macdonald, Phil; Letchumanan, Ramatha; Keese, Paul; Lema, Martin

    2015-01-01

    Risk assessment is a reasoned, structured approach to address uncertainty based on scientific and technical evidence. It forms the foundation for regulatory decision-making, which is bound by legislative and policy requirements, as well as the need for making timely decisions using available resources. In order to be most useful, environmental risk assessments (ERAs) for genetically modified (GM) crops should provide consistent, reliable, and transparent results across all types of GM crops, traits, and environments. The assessments must also separate essential information from scientific or agronomic data of marginal relevance or value for evaluating risk and complete the assessment in a timely fashion. Challenges in conducting ERAs differ across regulatory systems – examples are presented from Canada, Malaysia, and Argentina. One challenge faced across the globe is the conduct of risk assessments with limited resources. This challenge can be overcome by clarifying risk concepts, placing greater emphasis on data critical to assess environmental risk (for example, phenotypic and plant performance data rather than molecular data), and adapting advances in risk analysis from other relevant disciplines. PMID:26301217

  3. Building Better Environmental Risk Assessments.

    Science.gov (United States)

    Layton, Raymond; Smith, Joe; Macdonald, Phil; Letchumanan, Ramatha; Keese, Paul; Lema, Martin

    2015-01-01

    Risk assessment is a reasoned, structured approach to address uncertainty based on scientific and technical evidence. It forms the foundation for regulatory decision-making, which is bound by legislative and policy requirements, as well as the need for making timely decisions using available resources. In order to be most useful, environmental risk assessments (ERAs) for genetically modified (GM) crops should provide consistent, reliable, and transparent results across all types of GM crops, traits, and environments. The assessments must also separate essential information from scientific or agronomic data of marginal relevance or value for evaluating risk and complete the assessment in a timely fashion. Challenges in conducting ERAs differ across regulatory systems - examples are presented from Canada, Malaysia, and Argentina. One challenge faced across the globe is the conduct of risk assessments with limited resources. This challenge can be overcome by clarifying risk concepts, placing greater emphasis on data critical to assess environmental risk (for example, phenotypic and plant performance data rather than molecular data), and adapting advances in risk analysis from other relevant disciplines.

  4. Building better environmental risk assessments

    Directory of Open Access Journals (Sweden)

    Raymond eLayton

    2015-08-01

    Full Text Available Risk assessment is a reasoned, structured approach to address uncertainty based on scientific and technical evidence. It forms the foundation for regulatory decision making, which is bound by legislative and policy requirements, as well as the need for making timely decisions using available resources. In order to be most useful, environmental risk assessments (ERA for genetically modified (GM crops should provide consistent, reliable, and transparent results across all types of GM crops, traits, and environments. The assessments must also separate essential information from scientific or agronomic data of marginal relevance or value for evaluating risk and complete the assessment in a timely fashion. Challenges in conducting ERAs differ across regulatory systems – examples are presented from Canada, Malaysia, and Argentina. One challenge faced across the globe is the conduct of risk assessments with limited resources. This challenge can be overcome by clarifying risk concepts, placing greater emphasis on data critical to assess environmental risk (for example, phenotypic and plant performance data rather than molecular data, and adapting advances in risk analysis from other relevant disciplines.

  5. Influence of the human reliability in the assessment of the impact on the risk of changes of CLO; Influencia de la fiabilidad humana en la evaluacion del impacto en el riesgo de cambios de CLO

    Energy Technology Data Exchange (ETDEWEB)

    Martorell, P.; Martorell, S.; Marton, I.; Saiz, M.

    2014-07-01

    Treatment and study of epistemic uncertainties is of special importance in the application of the analysis of probabilistic security to informed decision-making in risk, as points out the guide regulatory 1,174 [1] (Regulatory Guide 1,174, RG1.174). Specifically, the RG 1.177 [2] details of the impact on risk assessment concerning changes in the technical operating specifications (ETF). Based on the framework defined by such regulatory guides, will be assessed the effect of uncertainties epistemic associated with the analysis of human reliability in the context of the limit conditions of operation. As an example of application, will be held a sensitivity study of the time of inoperability Completion Time, the Residual heat removal system. (Author)

  6. Competing risk theory and radiation risk assessment

    International Nuclear Information System (INIS)

    Groer, P.G.

    1980-01-01

    New statistical procedures are applied to estimate cumulative distribution functions (c.d.f.), force of mortality, and latent period for radiation-induced malignancies. It is demonstrated that correction for competing risks influences the shape of dose response curves, estimates of the latent period, and of the risk from ionizing radiations. The equivalence of the following concepts is demonstrated: force of mortality, hazard rate, and age or time specific incidence. This equivalence makes it possible to use procedures from reliability analysis and demography for radiation risk assessment. Two methods used by reliability analysts - hazard plotting and total time on test plots - are discussed in some detail and applied to characterize the hazard rate in radiation carcinogenesis. C.d.f.'s with increasing, decreasing, or constant hazard rate have different shapes and are shown to yield different dose-response curves for continuous irradiation. Absolute risk is shown to be a sound estimator only if the force of mortality is constant for the exposed and the control group. Dose-response relationships that use the absolute risk as a measure for the effect turn out to be special cases of dose-response relationships that measure the effect with cumulative incidence. (H.K.)

  7. Results of a Demonstration Assessment of Passive System Reliability Utilizing the Reliability Method for Passive Systems (RMPS)

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-04-26

    Advanced small modular reactor designs include many advantageous design features such as passively driven safety systems that are arguably more reliable and cost effective relative to conventional active systems. Despite their attractiveness, a reliability assessment of passive systems can be difficult using conventional reliability methods due to the nature of passive systems. Simple deviations in boundary conditions can induce functional failures in a passive system, and intermediate or unexpected operating modes can also occur. As part of an ongoing project, Argonne National Laboratory is investigating various methodologies to address passive system reliability. The Reliability Method for Passive Systems (RMPS), a systematic approach for examining reliability, is one technique chosen for this analysis. This methodology is combined with the Risk-Informed Safety Margin Characterization (RISMC) approach to assess the reliability of a passive system and the impact of its associated uncertainties. For this demonstration problem, an integrated plant model of an advanced small modular pool-type sodium fast reactor with a passive reactor cavity cooling system is subjected to a station blackout using RELAP5-3D. This paper discusses important aspects of the reliability assessment, including deployment of the methodology, the uncertainty identification and quantification process, and identification of key risk metrics.

  8. Nuclear Computerized Library for Assessing Reactor Reliability (NUCLARR): Data manual

    International Nuclear Information System (INIS)

    Gilbert, B.G.; Reece, W.J.; Gertman, D.I.; Gilmore, W.E.; Galyean, W.J.

    1990-12-01

    The Nuclear Computerized Library for Assessing Reactor Reliability (NUCLARR) is an automated data base management system for processing and storing human error probability and hardware component failure data. The NUCLARR system software resides on an IBM (or compatible) personal computer. NUCLARR can furnish the end user with data inputs for both human and hardware reliability analysis in support of a variety of risk assessment activities. The NUCLARR system is documented is a five-volume series of reports. Volume V: Data Manual provides a hard-copy representation of all data and related information available within the NUCLARR system software. This document is organized in three sections. Part 1 is the summary description, which presents an overview of the NUCLARR system and data processing procedures. Part 2 contains all data and information relevant to the human error probability (HEP) data side of NUCLARR. Data and information for the hardware component failure data (HCFD) side are presented in Part 3. 7 refs

  9. Nuclear Computerized Library for Assessing Reactor Reliability (NUCLARR)

    International Nuclear Information System (INIS)

    Gilbert, B.G.; Reece, W.J.; Gertman, D.I.; Gilmore, W.E.; Galyean, W.J.

    1990-12-01

    The Nuclear Computerized Library for Assessing Reactor Reliability (NUCLARR) is an automated data base management system for processing and storing human error probability and hardware component failure data. The NUCLARR system software resides on an IBM (or compatible) personal computer. NUCLARR can furnish the end user with data inputs for both human and hardware reliability analysis in support of a variety of risk assessment activities. The NUCLARR system is documented in a five-volume series of reports. Volume 5: Data Manual provides a hard-copy representation of all data and related information available within the NUCLARR system software. This document is organized in three sections. Part 1 is the summary description, which presents an overview of the NUCLARR system and data processing procedures. Part 2 contains all data and information relevant to the human error probability (HEP) data side of NUCLARR. Data and information for the hardware component failure data (HCFD) side are presented in Part 3. 7 refs

  10. Nuclear Computerized Library for Assessing Reactor Reliability (NUCLARR): Data manual

    International Nuclear Information System (INIS)

    Gilbert, B.G.; Reece, W.J.; Gertman, D.I.; Gilmore, W.E.; Galyean, W.J.

    1990-12-01

    The Nuclear Computerized Library for Assessing Reactor Reliability (NUCLARR) is an automated data base management system for processing and storing human error probability and hardware component failure data. The NUCLARR system software resides on an IBM (or compatible) personal computer. NUCLARR can furnish the end user with data inputs for both human and hardware reliability analysis in support of a variety of risk assessment activities. The NUCLARR system is documented in a five-volume series of reports. Volume V: Data Manual provides a hard-copy representation of all data and related information available within the NUCLARR system software. This document is organized in three sections. Part 1 is the summary description, which presents an overview of the NUCLARR system and data processing procedures. Part 2 contains all data and information relevant to the human error probability (HEP) side of NUCLARR. Data and information for the hardware component failure data (HCFD) side are presented in Part 3. 7 refs., 1 fig

  11. Nuclear Computerized Library for Assessing Reactor Reliability (NUCLARR): Summary description

    International Nuclear Information System (INIS)

    Gertman, D.I.; Gilmore, W.E.; Galyean, W.J.; Groh, M.R.; Gentillon, C.D.; Gilbert, B.G.; Reece, W.J.

    1990-05-01

    The Nuclear Computerized Library for Assessing Reactor Reliability (NUCLARR) is an automate data base management system for storing and processing human error probability and hardware component failure rate data. The NUCLARR system software resides on an IBM (or compatible) personal microcomputer. NUCLARR can be accessed by the end user to furnish data suitable for input in human and/or hardware reliability analysis to support a variety of risk assessment activities. The NUCLARR system is documented in a five-volume series of reports. This document Volume 1, of this series is the Summary Description, which presents an overview of the data management system, including a description of data collection, data qualification, data structure, and taxonomies. Programming activities, procedures for processing data, a user's guide, and hard copy data manual are presented in Volumes 2 through 5, NUREG/CR-4639

  12. Ecological risk assessment

    National Research Council Canada - National Science Library

    Suter, Glenn W; Barnthouse, L. W. (Lawrence W)

    2007-01-01

    Ecological risk assessment is commonly applied to the regulation of chemicals, the remediation of contaminated sites, the monitoring of importation of exotic organisms, the management of watersheds...

  13. Risk Assessment Overview

    Science.gov (United States)

    Prassinos, Peter G.; Lyver, John W., IV; Bui, Chinh T.

    2011-01-01

    Risk assessment is used in many industries to identify and manage risks. Initially developed for use on aeronautical and nuclear systems, risk assessment has been applied to transportation, chemical, computer, financial, and security systems among others. It is used to gain an understanding of the weaknesses or vulnerabilities in a system so modification can be made to increase operability, efficiency, and safety and to reduce failure and down-time. Risk assessment results are primary inputs to risk-informed decision making; where risk information including uncertainty is used along with other pertinent information to assist management in the decision-making process. Therefore, to be useful, a risk assessment must be directed at specific objectives. As the world embraces the globalization of trade and manufacturing, understanding the associated risk become important to decision making. Applying risk assessment techniques to a global system of development, manufacturing, and transportation can provide insight into how the system can fail, the likelihood of system failure and the consequences of system failure. The risk assessment can identify those elements that contribute most to risk and identify measures to prevent and mitigate failures, disruptions, and damaging outcomes. In addition, risk associated with public and environment impact can be identified. The risk insights gained can be applied to making decisions concerning suitable development and manufacturing locations, supply chains, and transportation strategies. While risk assessment has been mostly applied to mechanical and electrical systems, the concepts and techniques can be applied across other systems and activities. This paper provides a basic overview of the development of a risk assessment.

  14. Evaluation of thermal risk assessment

    International Nuclear Information System (INIS)

    Loos, J.J.; Perry, E.S.

    1993-01-01

    Risk assessment was done in 1983 to estimate the ecological hazard of increasing the generating load and thermal output of an electric generating station. Subsequently, long-term monitoring in the vicinity of the station allowed verification of the predictions made in the risk assessment. This presentation will review the efficacy of early risk assessment methods in producing useful predictions from a resource management point of view. In 1984, the Chalk Point Generating facility of the Potomac Electric Power Company increased it's median generating load by 100%. Prior to this operational change, the Academy of Natural Sciences of Philadelphia synthesized site specific data, model predictions, and results from literature to assess the risk of additional waste heat to the Patuxent River subestuary of Chesapeake Bay. Risk was expressed as the number of days per year that various species of fish and the blue crab would be expected to avoid the discharge vicinity. Accuracy of these predictions is assessed by comparing observed fish and crab distributions and their observed frequencies of avoidance to those predicted. It is concluded that the predictions of this early risk assessment were sufficiently accurate to produce a reliable resource management decision

  15. Biosafety Risk Assessment Methodology

    Energy Technology Data Exchange (ETDEWEB)

    Caskey, Susan Adele [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). International Biological Threat Reduction Program; Gaudioso, Jennifer M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). International Biological Threat Reduction Program; Salerno, Reynolds Mathewson [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). International Biological Threat Reduction Program; Wagner, Stefan M. [Public Health Agency of Canada, Winnipeg, MB (Canada). Canadian Science Centre for Human and Animal Health (CSCHAH); Shigematsu, Mika [National Inst. of Infectious Diseases (NIID), Tokyo (Japan); Risi, George [Infectious Disease Specialists, P.C, Missoula, MT (United States); Kozlovac, Joe [US Dept. of Agriculture (USDA)., Beltsville, MD (United States); Halkjaer-Knudsen, Vibeke [Statens Serum Inst., Copenhagen (Denmark); Prat, Esmeralda [Bayer CropScience, Monheim am Rhein (Germany)

    2010-10-01

    Laboratories that work with biological agents need to manage their safety risks to persons working the laboratories and the human and animal community in the surrounding areas. Biosafety guidance defines a wide variety of biosafety risk mitigation measures, which include measures which fall under the following categories: engineering controls, procedural and administrative controls, and the use of personal protective equipment; the determination of which mitigation measures should be used to address the specific laboratory risks are dependent upon a risk assessment. Ideally, a risk assessment should be conducted in a manner which is standardized and systematic which allows it to be repeatable and comparable. A risk assessment should clearly define the risk being assessed and avoid over complication.

  16. Offshore risk assessment

    CERN Document Server

    Vinnem, Jan-Erik

    2014-01-01

      Offshore Risk Assessment was the first book to deal with quantified risk assessment (QRA) as applied specifically to offshore installations and operations. Risk assessment techniques have been used for more than three decades in the offshore oil and gas industry, and their use is set to expand increasingly as the industry moves into new areas and faces new challenges in older regions.   This updated and expanded third edition has been informed by a major R&D program on offshore risk assessment in Norway and summarizes research from 2006 to the present day. Rooted with a thorough discussion of risk metrics and risk analysis methodology,  subsequent chapters are devoted to analytical approaches to escalation, escape, evacuation and rescue analysis of safety and emergency systems.   Separate chapters analyze the main hazards of offshore structures: fire, explosion, collision, and falling objects as well as structural and marine hazards. Risk mitigation and control are discussed, as well as an illustrat...

  17. 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.

  18. Probabilistic simulation applications to reliability assessments

    International Nuclear Information System (INIS)

    Miller, Ian; Nutt, Mark W.; Hill, Ralph S. III

    2003-01-01

    Probabilistic risk/reliability (PRA) analyses for engineered systems are conventionally based on fault-tree methods. These methods are mature and efficient, and are well suited to systems consisting of interacting components with known, low probabilities of failure. Even complex systems, such as nuclear power plants or aircraft, are modeled by the careful application of these approaches. However, for systems that may evolve in complex and nonlinear ways, and where the performance of components may be a sensitive function of the history of their working environments, fault-tree methods can be very demanding. This paper proposes an alternative method of evaluating such systems, based on probabilistic simulation using intelligent software objects to represent the components of such systems. Using a Monte Carlo approach, simulation models can be constructed from relatively simple interacting objects that capture the essential behavior of the components that they represent. Such models are capable of reflecting the complex behaviors of the systems that they represent in a natural and realistic way. (author)

  19. Operational risk assessment.

    Science.gov (United States)

    McKim, Vicky L

    2017-06-01

    In the world of risk management, which encompasses the business continuity disciplines, many types of risk require evaluation. Financial risk is most often the primary focus, followed by product and market risks. Another critical area, which typically lacks a thorough review or may be overlooked, is operational risk. This category encompasses many risk exposure types including those around building structures and systems, environmental issues, nature, neighbours, clients, regulatory compliance, network, data security and so on. At times, insurance carriers will assess internal hazards, but seldom do these assessments include more than a cursory look at other types of operational risk. In heavily regulated environments, risk assessments are required but may not always include thorough assessments of operational exposures. Vulnerabilities may linger or go unnoticed, only to become the catalyst for a business disruption at a later time, some of which are so severe that business recovery becomes nearly impossible. Businesses may suffer loss of clients as the result of a prolonged disruption of services. Comprehensive operational risk assessments can assist in identifying such vulnerabilities, exposures and threats so that the risk can be minimised or removed. This paper lays out how an assessment of this type can be successfully conducted.

  20. Risk assessment [Chapter 9

    Science.gov (United States)

    Dennis S. Ojima; Louis R. Iverson; Brent L. Sohngen; James M. Vose; Christopher W. Woodall; Grant M. Domke; David L. Peterson; Jeremy S. Littell; Stephen N. Matthews; Anantha M. Prasad; Matthew P. Peters; Gary W. Yohe; Megan M. Friggens

    2014-01-01

    What is "risk" in the context of climate change? How can a "risk-based framework" help assess the effects of climate change and develop adaptation priorities? Risk can be described by the likelihood of an impact occurring and the magnitude of the consequences of the impact (Yohe 2010) (Fig. 9.1). High-magnitude impacts are always...

  1. Chemical Risk Assessment

    Science.gov (United States)

    This course is aimed at providing an overview of the fundamental guiding principles and general methods used in chemical risk assessment. Chemical risk assessment is a complex and ever-evolving process. These principles and methods have been organized by the National Research Cou...

  2. Overview of risk assessment

    International Nuclear Information System (INIS)

    Rimington, J.D.

    1992-01-01

    The paper begins by defining some terms, and then refer to a number of technical and other difficulties. Finally it attempts to set out why risk assessment is important and what its purposes are. 2) First, risk and risk assessment - what are they?. 3) Risk is a subject of universal significance. Life is very uncertain, and we can achieve no object or benefit in it except by approaching nearer to particular hazards which lie between us and our objects. That approach represents acceptance of risk. 4) Risk assessment is a way of systematising our approach to hazard with a view to determining what is more and what is less risky. It helps us in the end to diminish our exposure while obtaining whatever benefits we have in mind, or to optimise the risks and the benefits

  3. Overview of risk assessment

    Energy Technology Data Exchange (ETDEWEB)

    Rimington, J D [Health and Safety Executive (United Kingdom)

    1992-07-01

    The paper begins by defining some terms, and then refer to a number of technical and other difficulties. Finally it attempts to set out why risk assessment is important and what its purposes are. 2) First, risk and risk assessment - what are they?. 3) Risk is a subject of universal significance. Life is very uncertain, and we can achieve no object or benefit in it except by approaching nearer to particular hazards which lie between us and our objects. That approach represents acceptance of risk. 4) Risk assessment is a way of systematising our approach to hazard with a view to determining what is more and what is less risky. It helps us in the end to diminish our exposure while obtaining whatever benefits we have in mind, or to optimise the risks and the benefits.

  4. 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)

  5. A model for assessing human cognitive reliability in PRA studies

    International Nuclear Information System (INIS)

    Hannaman, G.W.; Spurgin, A.J.; Lukic, Y.

    1985-01-01

    This paper summarizes the status of a research project sponsored by EPRI as part of the Probabilistic Risk Assessment (PRA) technology improvement program and conducted by NUS Corporation to develop a model of Human Cognitive Reliability (HCR). The model was synthesized from features identified in a review of existing models. The model development was based on the hypothesis that the key factors affecting crew response times are separable. The inputs to the model consist of key parameters the values of which can be determined by PRA analysts for each accident situation being assessed. The output is a set of curves which represent the probability of control room crew non-response as a function of time for different conditions affecting their performance. The non-response probability is then a contributor to the overall non-success of operating crews to achieve a functional objective identified in the PRA study. Simulator data and some small scale tests were utilized to illustrate the calibration of interim HCR model coefficients for different types of cognitive processing since the data were sparse. The model can potentially help PRA analysts make human reliability assessments more explicit. The model incorporates concepts from psychological models of human cognitive behavior, information from current collections of human reliability data sources and crew response time data from simulator training exercises

  6. State of risk assessment

    International Nuclear Information System (INIS)

    Conrad, J.

    1978-03-01

    In view of the growing importance assumed in recent years by scientific work on the calculation, quantification, evaluation and acceptance as well as behavior in the face of risks in general and more specifically, the risks of large industrial plants, the report attempts to provide a survey of the current situation, results and evaluation of this new branch of research, risk assessment. The emphasis of the report is on the basic discussion and criticism of the theoretical and methodological approaches used in the field of risk assessment (section 3). It is concerned above all with - methodical problems of determining and quantifying risks (3.1) - questions of the possibility of risk evaluation and comp arison (3.1, 3.2) - the premises of normative and empirical studies on decision making under risk (3.2, 3.3) - investigations into society's acceptance of risks involved in the introduction of new technologies (3.4) - attempts to combine various aspects of the field of risk assessment in a unified concept (3.5, 3.6, 3.7). Because risk assessment is embedded in the framework of decision theory and technology assessment, it can be implicitly evaluated at a more general level within this framework, as far as its possibilities and weaknesses of method and application are concerned (section 4). Sections 2 and 5 deal with the social context of origin and utilization of risk assessment. Finally, an attempt is made at a summary indicating the possible future development of risk assessment. (orig./HP) [de

  7. Lifetime Reliability Assessment of Concrete Slab Bridges

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    A procedure for lifetime assesment of the reliability of short concrete slab bridges is presented in the paper. Corrosion of the reinforcement is the deterioration mechanism used for estimating the reliability profiles for such bridges. The importance of using sensitivity measures is stressed....... Finally the produce is illustrated on 6 existing UK bridges....

  8. Measuring time and risk preferences: Reliability, stability, domain specificity

    NARCIS (Netherlands)

    Wölbert, E.M.; Riedl, A.M.

    2013-01-01

    To accurately predict behavior economists need reliable measures of individual time preferences and attitudes toward risk and typically need to assume stability of these characteristics over time and across decision domains. We test the reliability of two choice tasks for eliciting discount rates,

  9. An approach for assessing ALWR passive safety system reliability

    International Nuclear Information System (INIS)

    Hake, T.M.

    1991-01-01

    Many advanced light water reactor designs incorporate passive rather than active safety features for front-line accident response. A method for evaluating the reliability of these passive systems in the context of probabilistic risk assessment has been developed at Sandia National Laboratories. This method addresses both the component (e.g. valve) failure aspect of passive system failure, and uncertainties in system success criteria arising from uncertainties in the system's underlying physical processes. These processes provide the system's driving force; examples are natural circulation and gravity-induced injection. This paper describes the method, and provides some preliminary results of application of the approach to the Westinghouse AP600 design

  10. 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...

  11. Patient caries risk assessment

    DEFF Research Database (Denmark)

    Twetman, Svante; Fontana, Margherita

    2009-01-01

    Risk assessment is an essential component in the decision-making process for the correct prevention and management of dental caries. Multiple risk factors and indicators have been proposed as targets in the assessment of risk of future disease, varying sometimes based on the age group at which...... they are targeted. Multiple reviews and systematic reviews are available in the literature on this topic. This chapter focusses primarily on results of reviews based on longitudinal studies required to establish the accuracy of caries risk assessment. These findings demonstrate that there is a strong body...... of evidence to support that caries experience is still, unfortunately, the single best predictor for future caries development. In young children, prediction models which include a variety of risk factors seem to increase the accuracy of the prediction, while the usefulness of additional risk factors...

  12. Development of Energy and Reserve Pre-dispatch and Re-dispatch Models for Real-time Price Risk and Reliability Assessment

    DEFF Research Database (Denmark)

    Ding, Yi; Xie, Min; Wu, Qiuwei

    2014-01-01

    electricity market design may not cope with the future challenges the power system faces. The development of smart grid will enable power system scheduling and the electricity market to operate in a shorter time horizon for better integrating renewable energy sources into power systems. This paper presents......In the future energy framework of European Union and other countries, renewable energy plays an important role tackling the problems of the climate change and security of energy supply. The share of fluctuating and less predictable renewable power production will increase significantly the needs...... of securing proper balancing between generation and demand. The high penetration of renewable energy sources will also increase the burden of system operator for maintaining system reliabilities. However the current strategy of reliability management developed for conventional power systems and existing...

  13. A reliability assessment methodology for the VHTR passive safety system

    International Nuclear Information System (INIS)

    Lee, Hyungsuk; Jae, Moosung

    2014-01-01

    The passive safety system of a VHTR (Very High Temperature Reactor), which has recently attracted worldwide attention, is currently being considered for the design of safety improvements for the next generation of nuclear power plants in Korea. The functionality of the passive system does not rely on an external source of an electrical support system, but on the intelligent use of natural phenomena. Its function involves an ultimate heat sink for a passive secondary auxiliary cooling system, especially during a station blackout such as the case of the Fukushima Daiichi reactor accidents. However, it is not easy to quantitatively evaluate the reliability of passive safety for the purpose of risk analysis, considering the existing active system failure since the classical reliability assessment method cannot be applied. Therefore, we present a new methodology to quantify the reliability based on reliability physics models. This evaluation framework is then applied to of the conceptually designed VHTR in Korea. The Response Surface Method (RSM) is also utilized for evaluating the uncertainty of the maximum temperature of nuclear fuel. The proposed method could contribute to evaluating accident sequence frequency and designing new innovative nuclear systems, such as the reactor cavity cooling system (RCCS) in VHTR to be designed and constructed in Korea.

  14. Reliability Assessment for Low-cost Unmanned Aerial Vehicles

    Science.gov (United States)

    Freeman, Paul Michael

    Existing low-cost unmanned aerospace systems are unreliable, and engineers must blend reliability analysis with fault-tolerant control in novel ways. This dissertation introduces the University of Minnesota unmanned aerial vehicle flight research platform, a comprehensive simulation and flight test facility for reliability and fault-tolerance research. An industry-standard reliability assessment technique, the failure modes and effects analysis, is performed for an unmanned aircraft. Particular attention is afforded to the control surface and servo-actuation subsystem. Maintaining effector health is essential for safe flight; failures may lead to loss of control incidents. Failure likelihood, severity, and risk are qualitatively assessed for several effector failure modes. Design changes are recommended to improve aircraft reliability based on this analysis. Most notably, the control surfaces are split, providing independent actuation and dual-redundancy. The simulation models for control surface aerodynamic effects are updated to reflect the split surfaces using a first-principles geometric analysis. The failure modes and effects analysis is extended by using a high-fidelity nonlinear aircraft simulation. A trim state discovery is performed to identify the achievable steady, wings-level flight envelope of the healthy and damaged vehicle. Tolerance of elevator actuator failures is studied using familiar tools from linear systems analysis. This analysis reveals significant inherent performance limitations for candidate adaptive/reconfigurable control algorithms used for the vehicle. Moreover, it demonstrates how these tools can be applied in a design feedback loop to make safety-critical unmanned systems more reliable. Control surface impairments that do occur must be quickly and accurately detected. This dissertation also considers fault detection and identification for an unmanned aerial vehicle using model-based and model-free approaches and applies those

  15. A comparative evaluation of five human reliability assessment techniques

    International Nuclear Information System (INIS)

    Kirwan, B.

    1988-01-01

    A field experiment was undertaken to evaluate the accuracy, usefulness, and resources requirements of five human reliability quantification techniques (Techniques for Human Error Rate Prediction (THERP); Paired Comparisons, Human Error Assessment and Reduction Technique (HEART), Success Liklihood Index Method (SLIM)-Multi Attribute Utility Decomposition (MAUD), and Absolute Probability Judgement). This was achieved by assessing technique predictions against a set of known human error probabilities, and by comparing their predictions on a set of five realistic Probabilisitc Risk Assessment (PRA) human error. On a combined measure of accuracy THERP and Absolute Probability Judgement performed best, whilst HEART showed indications of accuracy and was lower in resources usage than other techniques. HEART and THERP both appear to benefit from using trained assessors in order to obtain the best results. SLIM and Paired Comparisons require further research on achieving a robust calibration relationship between their scale values and absolute probabilities. (author)

  16. GAR Global Risk Assessment

    Science.gov (United States)

    Maskrey, Andrew; Safaie, Sahar

    2015-04-01

    Disaster risk management strategies, policies and actions need to be based on evidence of current disaster loss and risk patterns, past trends and future projections, and underlying risk factors. Faced with competing demands for resources, at any level it is only possible to priorities a range of disaster risk management strategies and investments with adequate understanding of realised losses, current and future risk levels and impacts on economic growth and social wellbeing as well as cost and impact of the strategy. The mapping and understanding of the global risk landscape has been greatly enhanced by the latest iteration of the GAR Global Risk Assessment and the objective of this submission is to present the GAR global risk assessment which contributed to Global Assessment Report (GAR) 2015. This initiative which has been led by UNISDR, was conducted by a consortium of technical institutions from around the world and has covered earthquake, cyclone, riverine flood, and tsunami probabilistic risk for all countries of the world. In addition, the risks associated with volcanic ash in the Asia-Pacific region, drought in various countries in sub-Saharan Africa and climate change in a number of countries have been calculated. The presentation will share thee results as well as the experience including the challenges faced in technical elements as well as the process and recommendations for the future of such endeavour.

  17. Quantified reliability and risk assessment methodology in safety evaluation and licensing: survey of practice and trends in E.C. countries; partial contribution in decision making, perpective of safety goals

    International Nuclear Information System (INIS)

    Vinck, W.F.

    1982-01-01

    Quantified reliability analysis of structures and systems and the quantified risk-concept is increasingly developed and applied in safety evaluation and in the licensing/regulatory process where deterministic approaches are however still predominant. A description of the types of application and a survey of the diversified opinions and the problem areas (e.g. the validity of input data, uncertainties in consequence modelling, human factors, common mode failures, etc.) are given. The significance of quantified risk assessment and comparisons, as one of the contributors in the solution to acceptability of modern technology such as nuclear power production, is discussed. Other contributions, such as benefit assessment and cost-efficiency of risk reduction, are also put into perspective within the decision-making process and in the problem of actual acceptance of new technologies. The growing need of developing and agreeing on overall safety objectives (how safe is safe enough) is finally discussed, in the light of the increasing diversity of approaches in the interconnected areas of accident hypotheses/sequences, siting parameters and technical bases for emergency planning; the latter problem being also closely connected to decisional processes for acceptability and to actual acceptance

  18. Sovereign default risk assessment

    NARCIS (Netherlands)

    Rijken, H.A.; Altman, E.I.

    2013-01-01

    We propose a new approach toward assessing sovereign risk by examining rigorously the health and aggregate default risk of a nation's private corporate sector. Models can be utilised to measure the probability of default of the non-financial sector cumulatively for five years, both as an absolute

  19. Different Reliability Assessment Approaches for Wave Energy Converters

    DEFF Research Database (Denmark)

    Ambühl, Simon; Kramer, Morten Mejlhede; Sørensen, John Dalsgaard

    2015-01-01

    Reliability assessments are of importance for wave energy converters (WECs) due to the fact that accessibility might be limited in case of failure and maintenance. These failure rates can be adapted by reliability considerations. There are two different approaches to how reliability can...

  20. Probabilistic assessment of pressure vessel and piping reliability

    International Nuclear Information System (INIS)

    Sundararajan, C.

    1986-01-01

    The paper presents a critical review of the state-of-the-art in probabilistic assessment of pressure vessel and piping reliability. First the differences in assessing the reliability directly from historical failure data and indirectly by a probabilistic analysis of the failure phenomenon are discussed and the advantages and disadvantages are pointed out. The rest of the paper deals with the latter approach of reliability assessment. Methods of probabilistic reliability assessment are described and major projects where these methods are applied for pressure vessel and piping problems are discussed. An extensive list of references is provided at the end of the paper

  1. Reliability risks during the transition to competitive electricity markets

    International Nuclear Information System (INIS)

    Hughes, J.P.

    2005-01-01

    The Electricity Consumers Resource Council (ELCON) is a U.S. association representing industrial consumers of electricity, and is a long-standing advocate of competition in the electric power industry. However, because a reliable grid is necessary to support competitive wholesale markets, ELCON believes that the transmission system is an essential facility that must remain regulated. The initiatives discussed in this white paper represent significant steps that the National Electric Reliability Council (NERC) and the industry have taken to improve reliability in a competitive and restructured electric industry. Strategic manoeuvres of incumbent utilities to maintain market share were evaluated, as well as discrimination against potential competitors. It was suggested that, occasionally, indecisive federal policies have been taken advantage of by utilities. The unintended consequences of state restructuring policies that allow utilities to over-earn their revenue requirements were reviewed. NERC reliability standards will remain unenforceable until a new Electricity Reliability Organization has been certified. Flawed market designs and inadequate market power mitigation, as well as the financial distress of merchant generators, pose considerable risks. It was suggested that these risks could trigger transmission loading relief incidents, local outages or widespread outages. In the absence of mandatory reliability standards with penalties, and complementary market rules for mitigating generation and transmission market power, economic incentives will encourage other forms of opportunistic behavior that may be the root cause of other outages. Public concern regarding these risks to grid reliability may result in lost public support for competitive electricity markets. Proposed solutions include the certification of a new Electric Reliability Organization to establish and enforce mandatory reliability standards, and granting the Federal Energy Regulatory Commission

  2. Testing the reliability of the Fall Risk Screening Tool in an elderly ambulatory population.

    Science.gov (United States)

    Fielding, Susan J; McKay, Michael; Hyrkas, Kristiina

    2013-11-01

    To identify and test the reliability of a fall risk screening tool in an ambulatory outpatient clinic. The Fall Risk Screening Tool (Albert Lea Medical Center, MN, USA) was scripted for an interview format. Two interviewers separately screened a convenience sample of 111 patients (age ≥ 65 years) in an ambulatory outpatient clinic in a northeastern US city. The interviewers' scoring of fall risk categories was similar. There was good internal consistency (Cronbach's α = 0.834-0.889) and inter-rater reliability [intra-class correlation coefficients (ICC) = 0.824-0.881] for total, Risk Factor and Client's Health Status subscales. The Physical Environment scores indicated acceptable internal consistency (Cronbach's α = 0.742) and adequate reliability (ICC = 0.688). Two Physical Environment items (furniture and medical equipment condition) had low reliabilities [Kappa (K) = 0.323, P = 0.08; K = -0.078, P = 0.648), respectively. The scripted Fall Risk Screening Tool demonstrated good reliability in this sample. Rewording two Physical Environment items will be considered. A reliable instrument such as the scripted Fall Risk Screening Tool provides a standardised assessment for identifying high fall risk patients. This tool is especially useful because it assesses personal, behavioural and environmental factors specific to community-dwelling patients; the interview format also facilitates patient-provider interaction. © 2013 John Wiley & Sons Ltd.

  3. Probabilistic risk assessment methodology

    International Nuclear Information System (INIS)

    Shinaishin, M.A.

    1988-06-01

    The objective of this work is to provide the tools necessary for clear identification of: the purpose of a Probabilistic Risk Study, the bounds and depth of the study, the proper modeling techniques to be used, the failure modes contributing to the analysis, the classical and baysian approaches for manipulating data necessary for quantification, ways for treating uncertainties, and available computer codes that may be used in performing such probabilistic analysis. In addition, it provides the means for measuring the importance of a safety feature to maintaining a level of risk at a Nuclear Power Plant and the worth of optimizing a safety system in risk reduction. In applying these techniques so that they accommodate our national resources and needs it was felt that emphasis should be put on the system reliability analysis level of PRA. Objectives of such studies could include: comparing systems' designs of the various vendors in the bedding stage, and performing grid reliability and human performance analysis using national specific data. (author)

  4. Probabilistic risk assessment methodology

    Energy Technology Data Exchange (ETDEWEB)

    Shinaishin, M A

    1988-06-15

    The objective of this work is to provide the tools necessary for clear identification of: the purpose of a Probabilistic Risk Study, the bounds and depth of the study, the proper modeling techniques to be used, the failure modes contributing to the analysis, the classical and baysian approaches for manipulating data necessary for quantification, ways for treating uncertainties, and available computer codes that may be used in performing such probabilistic analysis. In addition, it provides the means for measuring the importance of a safety feature to maintaining a level of risk at a Nuclear Power Plant and the worth of optimizing a safety system in risk reduction. In applying these techniques so that they accommodate our national resources and needs it was felt that emphasis should be put on the system reliability analysis level of PRA. Objectives of such studies could include: comparing systems' designs of the various vendors in the bedding stage, and performing grid reliability and human performance analysis using national specific data. (author)

  5. Preliminary investigation on reliability assessment of passive safety system

    International Nuclear Information System (INIS)

    Huang Changfan; Kuang Bo

    2012-01-01

    The reliability evaluation of passive safety system plays an important part in probabilistic safety assessment (PSA) of nuclear power plant applying passive safety design, which depends quantitatively on reliabilities of passive safety system. According to the object of reliability assessment of passive safety system, relevant parameters are identified. Then passive system behavior during accident scenarios are studied. A practical example of this method is given for the case of reliability assessment of AP1000 passive heat removal system in loss of normal feedwater accident. Key and design parameters of PRHRS are identified and functional failure criteria are established. Parameter combinations acquired by Latin hyper~ cube sampling (LHS) in possible parametric ranges are input and calculations of uncertainty propagation through RELAP5/MOD3 code are carried out. Based on the calculations, sensitivity assessment on PRHRS functional criteria and reliability evaluation of the system are presented, which might provide further PSA with PRHR system reliability. (authors)

  6. Developments in Levee Reliability and Flood Risk Analysis in the Netherlands

    NARCIS (Netherlands)

    Jonkman, S.N.; Schweckendiek, T.

    2015-01-01

    This paper presents and overview of advances in flood risk and levee reliability analysis in the Netherlands. It is described how new safety standards – in the form of a target failure probability – have been derived on the basis of nationwide flood risk assessments which taken into account both

  7. Developing safety performance functions incorporating reliability-based risk measures.

    Science.gov (United States)

    Ibrahim, Shewkar El-Bassiouni; Sayed, Tarek

    2011-11-01

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

  8. Reliability assessment of underground shaft closure

    International Nuclear Information System (INIS)

    Fossum, A.F.; Munson, D.E.

    1994-01-01

    The intent of the WIPP, being constructed in the bedded geologic salt deposits of Southeastern New Mexico, is to provide the technological basis for the safe disposal of radioactive Transuranic (TRU) wastes generated by the defense programs of the United States. In determining this technological basis, advanced reliability and structural analysis techniques are used to determine the probability of time-to-closure of a hypothetical underground shaft located in an argillaceous salt formation and filled with compacted crushed salt. Before being filled with crushed salt for sealing, the shaft provides access to an underground facility. Reliable closure of the shaft depends upon the sealing of the shaft through creep closure and recompaction of crushed backfill. Appropriate methods are demonstrated to calculate cumulative distribution functions of the closure based on laboratory determined random variable uncertainty in salt creep properties

  9. Plant and control system reliability and risk model

    International Nuclear Information System (INIS)

    Niemelae, I.M.

    1986-01-01

    A new reliability modelling technique for control systems and plants is demonstrated. It is based on modified boolean algebra and it has been automated into an efficient computer code called RELVEC. The code is useful for getting an overall view of the reliability parameters or for an in-depth reliability analysis, which is essential in risk analysis, where the model must be capable of answering to specific questions like: 'What is the probability of this temperature limiter to provide a false alarm', or 'what is the probability of air pressure in this subsystem to drop below lower limit'. (orig./DG)

  10. Suprahyoid Muscle Complex: A Reliable Neural Assessment Tool For Dysphagia?

    DEFF Research Database (Denmark)

    Kothari, Mohit; Stubbs, Peter William; Pedersen, Asger Roer

    be a non-invasive reliable neural assessment tool for patients with dysphagia. Objective: To investigate the possibility of using the suprahyoid muscle complex (SMC) using surface electromyography (sEMG) to assess changes to neural pathways by determining the reliability of measurements in healthy...

  11. Reliability of assessment of adherence to an antimicrobial treatment guideline

    NARCIS (Netherlands)

    Mol, PGM; Gans, ROB; Panday, PVN; Degener, JE; Laseur, M; Haaijer-Ruskamp, FM

    Assessment procedures for adherence to a guideline must be reliable and credible. The aim of this study was to explore the reliability of assessment of adherence, taking account of the professional backgrounds of the observers. A secondary analysis explored the impact of case characteristics on

  12. Reliability assessment using the concept of possibility

    International Nuclear Information System (INIS)

    Ping, R.; Zhao, G.

    1994-01-01

    The role of the possibility theory in the quantitative approach to the reliability of large scale systems, in particular man-machine systems, is discussed. According to the original idea due to professor L.A. Zadeh, an error rate may be associated with a possibility distribution and a probability distribution. They describe the potentiallity and the actuality for error. This is especially important for the analysis of big accidents

  13. Taking the Risk Out of Risk Assessment

    Science.gov (United States)

    2005-01-01

    The ability to understand risks and have the right strategies in place when risky events occur is essential in the workplace. More and more organizations are being confronted with concerns over how to measure their risks or what kind of risks they can take when certain events transpire that could have a negative impact. NASA is one organization that faces these challenges on a daily basis, as effective risk management is critical to the success of its missions especially the Space Shuttle missions. On July 29, 1996, former NASA Administrator Daniel Goldin charged NASA s Office of Safety and Mission Assurance with developing a probabilistic risk assessment (PRA) tool to support decisions on the funding of Space Shuttle upgrades. When issuing the directive, Goldin said, "Since I came to NASA [in 1992], we've spent billions of dollars on Shuttle upgrades without knowing how much they improve safety. I want a tool to help base upgrade decisions on risk." Work on the PRA tool began immediately. The resulting prototype, the Quantitative Risk Assessment System (QRAS) Version 1.0, was jointly developed by NASA s Marshall Space Flight Center, its Office of Safety and Mission Assurance, and researchers at the University of Maryland. QRAS software automatically expands the reliability logic models of systems to evaluate the probability of highly detrimental outcomes occurring in complex systems that are subject to potential accident scenarios. Even in its earliest forms, QRAS was used to begin PRA modeling of the Space Shuttle. In parallel, the development of QRAS continued, with the goal of making it a world-class tool, one that was especially suited to NASA s unique needs. From the beginning, an important conceptual goal in the development of QRAS was for it to help bridge the gap between the professional risk analyst and the design engineer. In the past, only the professional risk analyst could perform, modify, use, and perhaps even adequately understand PRA. NASA wanted

  14. Chlorine transportation risk assessment

    International Nuclear Information System (INIS)

    Lautkaski, Risto; Mankamo, Tuomas.

    1977-02-01

    An assessment has been made on the toxication risk of the population due to the bulk rail transportation of liquid chlorine in Finland. Fourteen typical rail accidents were selected and their probability was estimated using the accident file of the Finnish State Railways. The probability of a chlorine leak was assessed for each type of accident separately using four leak size categories. The assessed leakage probability was dominated by station accidents, especially by collisions of a chlorine tanker and a locomotive. Toxication hazard areas were estimated for the leak categories. A simple model was constructed to describe the centring of the densely populated areas along the railway line. A comparison was made between the obtained risk and some other risks including those due to nuclear reactor accidents. (author)

  15. Human reliability assessment in a 99Mo/99mTc generator production facility using the standardized plant analysis risk-human (SPAR-H) technique.

    Science.gov (United States)

    Eyvazlou, Meysam; Dadashpour Ahangar, Ali; Rahimi, Azin; Davarpanah, Mohammad Reza; Sayyahi, Seyed Soheil; Mohebali, Mehdi

    2018-02-13

    Reducing human error is an important factor for enhancing safety protocols in various industries. Hence, analysis of the likelihood of human error in nuclear industries such as radiopharmaceutical production facilities has become more essential. This cross-sectional descriptive study was conducted to quantify the probability of human errors in a 99 Mo/ 99m Tc generator production facility in Iran. First, through expert interviews, the production process of the 99 Mo/ 99m Tc generator was analyzed using hierarchical task analysis (HTA). The standardized plant analysis risk-human (SPAR-H) method was then applied in order to calculate the probability of human error. Twenty tasks were determined using HTA. All of the eight performance shaping factors (PSF S ) were evaluated for the tasks. The mean probability of human error was 0.320. The highest and the lowest probability of human error in the 99 Mo/ 99m Tc generator production process, related to the 'loading the generator with the molybdenum solution' task and the 'generator elution' task, were 0.858 and 0.059, respectively. Required measures for reducing the human error probability (HEP) were suggested. These measures were derived from the level of PSF S that were evaluated in this study.

  16. Assessment of fracture risk

    International Nuclear Information System (INIS)

    Kanis, John A.; Johansson, Helena; Oden, Anders; McCloskey, Eugene V.

    2009-01-01

    Fractures are a common complication of osteoporosis. Although osteoporosis is defined by bone mineral density at the femoral neck, other sites and validated techniques can be used for fracture prediction. Several clinical risk factors contribute to fracture risk independently of BMD. These include age, prior fragility fracture, smoking, excess alcohol, family history of hip fracture, rheumatoid arthritis and the use of oral glucocorticoids. These risk factors in conjunction with BMD can be integrated to provide estimates of fracture probability using the FRAX tool. Fracture probability rather than BMD alone can be used to fashion strategies for the assessment and treatment of osteoporosis.

  17. Extrapolation Method for System Reliability Assessment

    DEFF Research Database (Denmark)

    Qin, Jianjun; Nishijima, Kazuyoshi; Faber, Michael Havbro

    2012-01-01

    of integrals with scaled domains. The performance of this class of approximation depends on the approach applied for the scaling and the functional form utilized for the extrapolation. A scheme for this task is derived here taking basis in the theory of asymptotic solutions to multinormal probability integrals......The present paper presents a new scheme for probability integral solution for system reliability analysis, which takes basis in the approaches by Naess et al. (2009) and Bucher (2009). The idea is to evaluate the probability integral by extrapolation, based on a sequence of MC approximations...... that the proposed scheme is efficient and adds to generality for this class of approximations for probability integrals....

  18. Reliability and maintainability assessment factors for reliable fault-tolerant systems

    Science.gov (United States)

    Bavuso, S. J.

    1984-01-01

    A long term goal of the NASA Langley Research Center is the development of a reliability assessment methodology of sufficient power to enable the credible comparison of the stochastic attributes of one ultrareliable system design against others. This methodology, developed over a 10 year period, is a combined analytic and simulative technique. An analytic component is the Computer Aided Reliability Estimation capability, third generation, or simply CARE III. A simulative component is the Gate Logic Software Simulator capability, or GLOSS. The numerous factors that potentially have a degrading effect on system reliability and the ways in which these factors that are peculiar to highly reliable fault tolerant systems are accounted for in credible reliability assessments. Also presented are the modeling difficulties that result from their inclusion and the ways in which CARE III and GLOSS mitigate the intractability of the heretofore unworkable mathematics.

  19. 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.

  20. Concerning ethical risk assessment

    International Nuclear Information System (INIS)

    Boeckle, F.

    1991-01-01

    After a fundamental consideration of the concept of responsibility and 'long-term responsibility' for late sequelae, the problems of an ehtical assessment of risks were illustrated: The concept of risk itself poses three problems - predicting the probability of occurrence, assessing the damage = subjective classification of the degree of damage, determining whether the advantages outweigh the risks. It is not possible to weigh the advantages and risks against each other without assessing the goals and the priorities which have been set. Here ethics is called for, because it concerns itself with the reasonableness of evaluative decisions. Its task is to enable us to become aware of and comprehend our system of values in all of its complexity in reference to real life. Ethics can only fulfill its task if it helps us to adopt an integral perspective, i.e. if it centers on the human being. 'One must assess all technical and economic innovations in terms of whether they are beneficial to the development of mankind on a long-term basis. They are only to be legitimized insofar as they prove themselves to be a means of liberating mankind and contributing to his sense of dignity and identity, as a means of bringing human beings together and encouraging them to care for one another, and as a means of protecting the natural basis of our existence. (orig./HSCH) [de

  1. A method to assign failure rates for piping reliability assessments

    International Nuclear Information System (INIS)

    Gamble, R.M.; Tagart, S.W. Jr.

    1991-01-01

    This paper reports on a simplified method that has been developed to assign failure rates that can be used in reliability and risk studies of piping. The method can be applied on a line-by-line basis by identifying line and location specific attributes that can lead to piping unreliability from in-service degradation mechanisms and random events. A survey of service experience for nuclear piping reliability also was performed. The data from this survey provides a basis for identifying in-service failure attributes and assigning failure rates for risk and reliability studies

  2. Planning of operation & maintenance using risk and reliability based methods

    DEFF Research Database (Denmark)

    Florian, Mihai; Sørensen, John Dalsgaard

    2015-01-01

    Operation and maintenance (OM) of offshore wind turbines contributes with a substantial part of the total levelized cost of energy (LCOE). The objective of this paper is to present an application of risk- and reliability-based methods for planning of OM. The theoretical basis is presented...

  3. Assessing the Impact of Imperfect Diagnosis on Service Reliability

    DEFF Research Database (Denmark)

    Grønbæk, Lars Jesper; Schwefel, Hans-Peter; Kjærgaard, Jens Kristian

    2010-01-01

    , representative diagnosis performance metrics have been defined and their closed-form solutions obtained for the Markov model. These equations enable model parameterization from traces of implemented diagnosis components. The diagnosis model has been integrated in a reliability model assessing the impact...... of the diagnosis functions for the studied reliability problem. In a simulation study we finally analyze trade-off properties of diagnosis heuristics from literature, map them to the analytic Markov model, and investigate its suitability for service reliability optimization....

  4. Quantification of human reliability in probabilistic safety assessment

    International Nuclear Information System (INIS)

    Hirschberg, S.; Dankg, Vinh N.

    1996-01-01

    Human performance may substantially influence the reliability and safety of complex technical systems. For this reason, Human Reliability Analysis (HRA) constitutes an important part of Probabilistic Safety Assessment (PSAs) or Quantitative Risk Analyses (QRAs). The results of these studies as well as analyses of past accidents and incidents clearly demonstrate the importance of human interactions. The contribution of human errors to the core damage frequency (CDF), as estimated in the Swedish nuclear PSAs, are between 15 and 88%. A survey of the FRAs in the Swiss PSAs shows that also for the Swiss nuclear power plants the estimated HE contributions are substantial (49% of the CDF due to internal events in the case of Beznau and 70% in the case of Muehleberg; for the total CDF, including external events, 25% respectively 20%). Similar results can be extracted from the PSAs carried out for French, German, and US plants. In PSAs or QRAs, the adequate treatment of the human interactions with the system is a key to the understanding of accident sequences and their relative importance to overall risk. The main objectives of HRA are: first, to ensure that the key human interactions are systematically identified and incorporated into the safety analysis in a traceable manner, and second, to quantify the probabilities of their success and failure. Adopting a structured and systematic approach to the assessment of human performance makes it possible to provide greater confidence that the safety and availability of human-machine systems is not unduly jeopardized by human performance problems. Section 2 discusses the different types of human interactions analysed in PSAs. More generally, the section presents how HRA fits in the overall safety analysis, that is, how the human interactions to be quantified are identified. Section 3 addresses the methods for quantification. Section 4 concludes the paper by presenting some recommendations and pointing out the limitations of the

  5. How simulation of failure risk can improve structural reliability - application to pressurized components and pipes

    OpenAIRE

    Cioclov, Dimitru Dragos

    2013-01-01

    Probabilistic methods for failure risk assessment are introduced, with reference to load carrying structures, such as pressure vessels (PV) and components of pipes systems. The definition of the failure risk associated with structural integrity is made in the context of the general approach to structural reliability. Sources of risk are summarily outlined with emphasis on variability and uncertainties (V&U) which might be encountered in the analysis. To highlight the problem, in its practical...

  6. On risk assessment of energy production

    International Nuclear Information System (INIS)

    Kunii, Katsuhiko

    2005-07-01

    Today we cannot ignore the risk of health and/or environment by energy production such as power generation since the risk has been made large enough. In this report an information survey has been done in order to know the outline and points of risk assessment. Based on the information of reports and literature about risk assessment, have been surveyed mainly the external cost assessment of power generation (in which quantification of health and/or environment risk has been done), in addition, risks of disasters, accidents, investments, finance etc. and impacts of those risks on social activities. The remarks obtained by the survey are as follows: 1) Some of external cost assessment of power generation show different results even if the assessment conditions of technology, site, etc. are mostly the same. It is necessary to remark on the information such as basic data, model, background, application limit of assessment considering the reliability. 2) Especially it is considered that the reliability of risk assessment is not enough at present because of the lack of basic data. (author)

  7. Risk assessment: 'A consumer's perspective'

    Energy Technology Data Exchange (ETDEWEB)

    Waterhouse, Rachel [Consumer' s Association, Health and Safety Commission (United Kingdom)

    1992-07-01

    The paper assesses the concept of risk, risk assessment and tolerability of risk from consumer point of view. Review of existing UK and EC directives on certain products and appliances is also covered.

  8. Risk assessment: 'A consumer's perspective'

    International Nuclear Information System (INIS)

    Waterhouse, Rachel

    1992-01-01

    The paper assesses the concept of risk, risk assessment and tolerability of risk from consumer point of view. Review of existing UK and EC directives on certain products and appliances is also covered

  9. Reliability of risk-adjusted outcomes for profiling hospital surgical quality.

    Science.gov (United States)

    Krell, Robert W; Hozain, Ahmed; Kao, Lillian S; Dimick, Justin B

    2014-05-01

    Quality improvement platforms commonly use risk-adjusted morbidity and mortality to profile hospital performance. However, given small hospital caseloads and low event rates for some procedures, it is unclear whether these outcomes reliably reflect hospital performance. To determine the reliability of risk-adjusted morbidity and mortality for hospital performance profiling using clinical registry data. A retrospective cohort study was conducted using data from the American College of Surgeons National Surgical Quality Improvement Program, 2009. Participants included all patients (N = 55,466) who underwent colon resection, pancreatic resection, laparoscopic gastric bypass, ventral hernia repair, abdominal aortic aneurysm repair, and lower extremity bypass. Outcomes included risk-adjusted overall morbidity, severe morbidity, and mortality. We assessed reliability (0-1 scale: 0, completely unreliable; and 1, perfectly reliable) for all 3 outcomes. We also quantified the number of hospitals meeting minimum acceptable reliability thresholds (>0.70, good reliability; and >0.50, fair reliability) for each outcome. For overall morbidity, the most common outcome studied, the mean reliability depended on sample size (ie, how high the hospital caseload was) and the event rate (ie, how frequently the outcome occurred). For example, mean reliability for overall morbidity was low for abdominal aortic aneurysm repair (reliability, 0.29; sample size, 25 cases per year; and event rate, 18.3%). In contrast, mean reliability for overall morbidity was higher for colon resection (reliability, 0.61; sample size, 114 cases per year; and event rate, 26.8%). Colon resection (37.7% of hospitals), pancreatic resection (7.1% of hospitals), and laparoscopic gastric bypass (11.5% of hospitals) were the only procedures for which any hospitals met a reliability threshold of 0.70 for overall morbidity. Because severe morbidity and mortality are less frequent outcomes, their mean

  10. Integral risk assessment

    International Nuclear Information System (INIS)

    Chakraborty, S.; Yadigaroglu, G.

    1991-01-01

    The series of lectures which forms the basis of this book and took place in the winter of 1989/90 at the ETH in Zuerich were held for the purpose of discussing the stage of development of our system of ethics in view of the extremely fast pace of technological progress and the risks which accompany it. Legal, psychological and political aspects of the problem were examined, but the emphasis was placed on ethical aspects. The effects which are examined in conventional risk analyses can be considered as a part of the ethical and social aspects involved, and in turn, the consideration of ethical and social aspects can be viewed as an extension of the conventional form of risk analysis. In any case, among risk experts, the significance of ethical and social factors is uncontested, especially as regards activities which can have far-reaching repurcussions. Some objective difficulties interfere with this goal, however: - No generally acknowledged set of ethical values exists. - Cultural influences and personal motives can interfere. - Normally a risk assessment is carried out in reference to individual facilities and within a small, clearly defined framework. Under certain circumstances, generalizations which are made for complete technological systems can lead to completely different conclusions. One contribution deals with integral views of the risks of atomic energy from an ethical and social perspective. (orig.) [de

  11. 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

  12. Decision-theoretic methodology for reliability and risk allocation in nuclear power plants

    International Nuclear Information System (INIS)

    Cho, N.Z.; Papazoglou, I.A.; Bari, R.A.; El-Bassioni, A.

    1985-01-01

    This paper describes a methodology for allocating reliability and risk to various reactor systems, subsystems, components, operations, and structures in a consistent manner, based on a set of global safety criteria which are not rigid. The problem is formulated as a multiattribute decision analysis paradigm; the multiobjective optimization, which is performed on a PRA model and reliability cost functions, serves as the guiding principle for reliability and risk allocation. The concept of noninferiority is used in the multiobjective optimization problem. Finding the noninferior solution set is the main theme of the current approach. The assessment of the decision maker's preferences could then be performed more easily on the noninferior solution set. Some results of the methodology applications to a nontrivial risk model are provided and several outstanding issues such as generic allocation and preference assessment are discussed

  13. 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

  14. 75 FR 66038 - Planning Resource Adequacy Assessment Reliability Standard

    Science.gov (United States)

    2010-10-27

    ..., providing a common framework for resource adequacy analysis, assessment, and documentation) effectively and...://www.nerc.com/commondocs.php?cd=2 . D. Proposed Effective Date 24. Proposed regional Reliability...

  15. [Evaluation of Suicide Risk Levels in Hospitals: Validity and Reliability Tests].

    Science.gov (United States)

    Macagnino, Sandro; Steinert, Tilman; Uhlmann, Carmen

    2018-05-01

    Examination of in-hospital suicide risk levels concerning their validity and their reliability. The internal suicide risk levels were evaluated in a cross sectional study of in 163 inpatients. A reliability check was performed via determining interrater-reliability of senior physician, therapist and the responsible nurse. Within the scope of the validity check, we conducted analyses of criterion validity and construct validity. For the total sample an "acceptable" to "good" interrater-reliability (Kendalls W = .77) of suicide risk levels were obtained. Schizophrenic disorders showed the lowest values, for personality disorders we found the highest level of interrater-reliability. When examining the criterion validity, Item-9 of the BDI-II is substantial correlated to our suicide risk levels (ρ m  = .54, p validity check, affective disorders showed the highest correlation (ρ = .77), compatible also with "convergent validity". They differed with schizophrenic disorders which showed the least concordance (ρ = .43). In-hospital suicide risk levels may represent an important contribution to the assessment of suicidal behavior of inpatients experiencing psychiatric treatment due to their overall good validity and reliability. © Georg Thieme Verlag KG Stuttgart · New York.

  16. Preventive risk assessment in forensic child and youth care

    NARCIS (Netherlands)

    Assink, M.

    2017-01-01

    Risk assessment is central to the work of forensic mental health professionals, since it serves as a guide for prevention and intervention strategies. For effective risk assessment, knowledge on risk factors and their effects as well as the availability of valid and reliable instruments for risk

  17. Reliability Assessment and Reliability-Based Inspection and Maintenance of Offshore Wind Turbines

    DEFF Research Database (Denmark)

    Ramírez, José G. Rangel; Sørensen, John Dalsgaard

    2009-01-01

    Probabilistic methodologies represent an important tool to identify the suitable strategy to inspect and deal with the deterioration in structures such as offshore wind turbines (OWT). Reliability based methods such as Risk Based Inspection (RBI) planning may represent a proper methodology to opt...

  18. Risk assessment and risk evaluation

    International Nuclear Information System (INIS)

    Niehaus, F.

    1978-01-01

    With the help of results of investigations and model calculations the risk of nuclear energy in routine operation is shown. In this context it is pointed out that the excellent operation results of reactors all over the world have led to the acceptability of risks from local loads no longer being in question. The attention of radiation protection is therefore focused on the emissions of long-living isotopes which collect in the atmosphere. With LWRs the risk of accidents is so minimal that statistical data is, and never will be available. One has to therefore fall back upon the so-called fault tree analyses. On the subject of risk evalution the author referred to a poll in Austria. From the result of this investigation one might conclude that nuclear energy serves as a crystallization point for a discussion of varying concepts for future development. More attention should be paid to this aspect from both sides, in order to objectify the further expansion of this source of energy. (orig./HP) [de

  19. Forward reliability markets: Less risk, less market power, more efficiency

    International Nuclear Information System (INIS)

    Cramton, Peter; Stoft, Steven

    2008-01-01

    A forward reliability market is presented. The market coordinates new entry through the forward procurement of reliability options - physical capacity bundled with a financial option to supply energy above a strike price. The market assures adequate generating resources and prices capacity from the bids of competitive new entry in an annual auction. Efficient performance incentives are maintained from a load-following obligation to supply energy above the strike price. The capacity payment fully hedges load from high spot prices, and reduces supplier risk as well. Market power is reduced in the spot market, since suppliers enter the spot market with a nearly balanced position in times of scarcity. Market power in the reliability market is addressed by not allowing existing supply to impact the capacity price. The approach, which has been adopted in New England and Colombia, is readily adapted to either a thermal system or a hydro system. (author)

  20. Hazard waste risk assessment

    International Nuclear Information System (INIS)

    Hawley, K.A.; Napier, B.A.

    1986-01-01

    Pacific Northwest Laboratory continued to provide technical assistance to the Department of Energy (DOE) Office of Operational Safety (OOS) in the area of risk assessment for hazardous and radioactive-mixed waste management. The overall objective is to provide technical assistance to OOS in developing cost-effective risk assessment tools and strategies for bringing DOE facilities into compliance with the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA or Superfund) and the Resource Conservation and Recovery Act (RCRA). Major efforts during FY 1985 included (1) completing the modification of the Environmental Protection Agency (EPA) Hazard Ranking System (HRS) and developing training manuals and courses to assist in field office implementation of the modified Hazard Ranking System (mHRS); (2) initiating the development of a system for reviewing field office HRS/mHRS evaluations for appropriate use of data and appropriate application of the methodology; (3) initiating the development of a data base management system to maintain all field office HRS/mHRS scoring sheets and to support the master OOS environmental data base system; (4) developing implementation guidance for Phase I of the DOE CERCLA Program, Installation Assessment; (5) continuing to develop an objective, scientifically based methodology for DOE management to use in establishing priorities for conducting site assessments under Phase II of the DOE CERCLA Program, Confirmation; and (6) participating in developing the DOE response to EPA on the proposed listing of three sites on the National Priorities List

  1. Experiences in Germany with reliability data assessment, results and current problems

    International Nuclear Information System (INIS)

    Homke, P.; Kutsch, W.; Lindauer, E.

    1982-01-01

    This paper gives a survey on reliability data assessment in the FRG. The activities, which were carried out for the German Risk Assessment Study are presented together with selected results. A systematic data collection in a nuclear power plant is described and the experiences are discussed, which were gained in this project

  2. Reliability and comparison of acromion assessment techniques on x-ray and magnetic resonance imaging (reliability of acromion assessment techniques)

    International Nuclear Information System (INIS)

    Viskontas, D.G.; MacDermid, J.C.; Drosdowech, D.S.; Garvin, G.J.; Romano, W.M.; Faber, K.J.

    2005-01-01

    To determine the reliability and correlation of plain radiography and magnetic resonance imaging (MRI) in the assessment of acromion morphology. Materials and Methods: Acromion morphology was assessed using the lateral acromion angle (LAA) and the acromion-humeral interval (AHI). Thirty patients who had x-rays and MRI for impingement syndrome were included. Six blinded observers assessed the acromion morphology subjectively and objectively. Results: Neither acromion assessment technique demonstrated a positive correlation (kappa and intraclass coefficient 0.55) when measured objectively by experienced observers. Conclusion: The LAA and the AHI are both reliable acromion assessment techniques on X-ray and MRI when measured objectively and by experienced observers. (author)

  3. Sequential optimization and reliability assessment method for metal forming processes

    International Nuclear Information System (INIS)

    Sahai, Atul; Schramm, Uwe; Buranathiti, Thaweepat; Chen Wei; Cao Jian; Xia, Cedric Z.

    2004-01-01

    Uncertainty is inevitable in any design process. The uncertainty could be due to the variations in geometry of the part, material properties or due to the lack of knowledge about the phenomena being modeled itself. Deterministic design optimization does not take uncertainty into account and worst case scenario assumptions lead to vastly over conservative design. Probabilistic design, such as reliability-based design and robust design, offers tools for making robust and reliable decisions under the presence of uncertainty in the design process. Probabilistic design optimization often involves double-loop procedure for optimization and iterative probabilistic assessment. This results in high computational demand. The high computational demand can be reduced by replacing computationally intensive simulation models with less costly surrogate models and by employing Sequential Optimization and reliability assessment (SORA) method. The SORA method uses a single-loop strategy with a series of cycles of deterministic optimization and reliability assessment. The deterministic optimization and reliability assessment is decoupled in each cycle. This leads to quick improvement of design from one cycle to other and increase in computational efficiency. This paper demonstrates the effectiveness of Sequential Optimization and Reliability Assessment (SORA) method when applied to designing a sheet metal flanging process. Surrogate models are used as less costly approximations to the computationally expensive Finite Element simulations

  4. Risk assessment handbook

    International Nuclear Information System (INIS)

    Farmer, F.G.; Jones, J.L.; Hunt, R.N.; Roush, M.L.; Wierman, T.E.

    1990-09-01

    The Probabilistic Risk Assessment Unit at EG ampersand G Idaho has developed this handbook to provide guidance to a facility manager exploring the potential benefit to be gained by performance of a risk assessment properly scoped to meet local needs. This document is designed to help the manager control the resources expended commensurate with the risks being managed and to assure that the products can be used programmatically to support future needs in order to derive maximum beneflt from the resources expended. We present a logical and functional mapping scheme between several discrete phases of project definition to ensure that a potential customer, working with an analyst, is able to define the areas of interest and that appropriate methods are employed in the analysis. In addition the handbook is written to provide a high-level perspective for the analyst. Previously, the needed information was either scattered or existed only in the minds of experienced analysts. By compiling this information and exploring the breadth of knowledge which exists within the members of the PRA Unit, the functional relationships between the customers' needs and the product have been established

  5. Reliability and risk-based planning of operation and maintenance of offshore wind turbines

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Florian, Mihai; Berzonskis, Arvydas

    2016-01-01

    costly (and safe), and it is important to include in the reliability assessment the information obtained during operation (from condition monitoring and inspections) and the maintenance performed (incl. repairs and replacements). The paper presents a risk-based approach for optimal planning of Operation...

  6. 2007 TOXICOLOGY AND RISK ASSESSMENT ...

    Science.gov (United States)

    EPA has announced The 2007 Toxicology and Risk Assessment Conference Cincinnati Marriott North, West Chester (Cincinnati), OHApril 23- 26, 2007 - Click to register!The Annual Toxicology and Risk Assessment Conference is a unique meeting where several Government Agencies come together to discuss toxicology and risk assessment issues that are not only of concern to the government, but also to a broader audience including academia and industry. The theme of this year's conference is Emerging Issues and Challenges in Risk Assessment and the preliminary agenda includes: Plenary Sessions and prominent speakers (tentative) include: Issues of Emerging Chemical ContaminantsUncertainty and Variability in Risk Assessment Use of Mechanistic data in IARC evaluationsParallel Sessions:Uncertainty and Variability in Dose-Response Assessment Recent Advances in Toxicity and Risk Assessment of RDX The Use of Epidemiologic Data for Risk Assessment Applications Cumulative Health Risk Assessment:

  7. Translation, reliability, and clinical utility of the Melbourne Assessment 2.

    Science.gov (United States)

    Gerber, Corinna N; Plebani, Anael; Labruyère, Rob

    2017-10-12

    The aims were to (i) provide a German translation of the Melbourne Assessment 2 (MA2), a quantitative test to measure unilateral upper limb function in children with neurological disabilities and (ii) to evaluate its reliability and aspects of clinical utility. After its translation into German and approval of the back translation by the original authors, the MA2 was performed and videotaped twice with 30 children with neuromotor disorders. For each participant, two raters scored the video of the first test for inter-rater reliability. To determine test-retest reliability, one rater additionally scored the video of the second test while the other rater repeated the scoring of the first video to evaluate intra-rater reliability. Time needed for rater training, test administration, and scoring was recorded. The four subscale scores showed excellent intra-, inter-rater, and test-retest reliability with intraclass correlation coefficients of 0.90-1.00 (95%-confidence intervals 0.78-1.00). Score items revealed substantial to almost perfect intra-rater reliability (weighted kappa k w  = 0.66-1.00) for the more affected side. Score item inter-rater and test-retest reliability of the same extremity were, with one exception, moderate to almost perfect (k w  = 0.42-0.97; k w  = 0.40-0.89). Furthermore, the MA2 was feasible and acceptable for patients and clinicians. The MA2 showed excellent subscale and moderate to almost perfect score item reliability. Implications for Rehabilitation There is a lack of high-quality studies about psychometric properties of upper limb measurement tools in the neuropediatric population. The Melbourne Assessment 2 is a promising tool for reliable measurement of unilateral upper limb movement quality in the neuropediatric population. The Melbourne Assessment 2 is acceptable and practicable to therapists and patients for routine use in clinical care.

  8. Is the Frontal Assessment Battery reliable in ALS patients?

    NARCIS (Netherlands)

    Raaphorst, J.; Beeldman, E.; Jaeger, B.; Schmand, B.A.; Berg, L.H. van den; Weikamp, J.G.; Schelhaas, H.J.; Visser, M. de; Haan, R.J. de

    2013-01-01

    The assessment of frontal functions in ALS patients is important because of the overlap with the behavioural variant of frontotemporal dementia (bvFTD). We investigated the applicability and reliability of the Frontal Assessment Battery (FAB) within a cohort of predominantly prevalent ALS patients.

  9. Photographic assessment of burn size and depth: reliability and validity

    NARCIS (Netherlands)

    Hop, M.; Moues, C.; Bogomolova, K.; Nieuwenhuis, M.; Oen, I.; Middelkoop, E.; Breederveld, R.; de Baar, M.

    2014-01-01

    Objective: The aim of this study was to examine the reliability and validity of using photographs of burns to assess both burn size and depth. Method: Fifty randomly selected photographs taken on day 0-1 post burn were assessed by seven burn experts and eight referring physicians. Inter-rater

  10. Valid and Reliable Science Content Assessments for Science Teachers

    Science.gov (United States)

    Tretter, Thomas R.; Brown, Sherri L.; Bush, William S.; Saderholm, Jon C.; Holmes, Vicki-Lynn

    2013-01-01

    Science teachers' content knowledge is an important influence on student learning, highlighting an ongoing need for programs, and assessments of those programs, designed to support teacher learning of science. Valid and reliable assessments of teacher science knowledge are needed for direct measurement of this crucial variable. This paper…

  11. Reliability and validity of subjective assessment of lumbar lordosis in ...

    African Journals Online (AJOL)

    Radiological assessment of lumbar lordotic curve aids in early diagnosis of conditions even before neurologic changes set in. Objective: To ascertain the level of reliability and validity of subjective assessment of lumbar lordosis in conventional radiography. Design: A blinded, repeated-measures diagnostic test was carried ...

  12. A heuristic-based approach for reliability importance assessment of energy producers

    International Nuclear Information System (INIS)

    Akhavein, A.; Fotuhi Firuzabad, M.

    2011-01-01

    Reliability of energy supply is one of the most important issues of service quality. On one hand, customers usually have different expectations for service reliability and price. On the other hand, providing different level of reliability at load points is a challenge for system operators. In order to take reasonable decisions and obviate reliability implementation difficulties, market players need to know impacts of their assets on system and load-point reliabilities. One tool to specify reliability impacts of assets is the criticality or reliability importance measure by which system components can be ranked based on their effect on reliability. Conventional methods for determination of reliability importance are essentially on the basis of risk sensitivity analysis and hence, impose prohibitive calculation burden in large power systems. An approach is proposed in this paper to determine reliability importance of energy producers from perspective of consumers or distribution companies in a composite generation and transmission system. In the presented method, while avoiding immense computational burden, the energy producers are ranked based on their rating, unavailability and impact on power flows in the lines connecting to the considered load points. Study results on the IEEE reliability test system show successful application of the proposed method. - Research highlights: → Required reliability level at load points is a concern in modern power systems. → It is important to assess reliability importance of energy producers or generators. → Generators can be ranked based on their impacts on power flow to a selected area. → Ranking of generators is an efficient tool to assess their reliability importance.

  13. A computational Bayesian approach to dependency assessment in system reliability

    International Nuclear Information System (INIS)

    Yontay, Petek; Pan, Rong

    2016-01-01

    Due to the increasing complexity of engineered products, it is of great importance to develop a tool to assess reliability dependencies among components and systems under the uncertainty of system reliability structure. In this paper, a Bayesian network approach is proposed for evaluating the conditional probability of failure within a complex system, using a multilevel system configuration. Coupling with Bayesian inference, the posterior distributions of these conditional probabilities can be estimated by combining failure information and expert opinions at both system and component levels. Three data scenarios are considered in this study, and they demonstrate that, with the quantification of the stochastic relationship of reliability within a system, the dependency structure in system reliability can be gradually revealed by the data collected at different system levels. - Highlights: • A Bayesian network representation of system reliability is presented. • Bayesian inference methods for assessing dependencies in system reliability are developed. • Complete and incomplete data scenarios are discussed. • The proposed approach is able to integrate reliability information from multiple sources at multiple levels of the system.

  14. Surgery Risk Assessment (SRA) Database

    Data.gov (United States)

    Department of Veterans Affairs — The Surgery Risk Assessment (SRA) database is part of the VA Surgical Quality Improvement Program (VASQIP). This database contains assessments of selected surgical...

  15. Reliability of sonographic assessment of tendinopathy in tennis elbow.

    Science.gov (United States)

    Poltawski, Leon; Ali, Syed; Jayaram, Vijay; Watson, Tim

    2012-01-01

    To assess the reliability and compute the minimum detectable change using sonographic scales to quantify the extent of pathology and hyperaemia in the common extensor tendon in people with tennis elbow. The lateral elbows of 19 people with tennis elbow were assessed sonographically twice, 1-2 weeks apart. Greyscale and power Doppler images were recorded for subsequent rating of abnormalities. Tendon thickening, hypoechogenicity, fibrillar disruption and calcification were each rated on four-point scales, and scores were summed to provide an overall rating of structural abnormality; hyperaemia was scored on a five point scale. Inter-rater reliability was established using the intraclass correlation coefficient (ICC) to compare scores assigned independently to the same set of images by a radiologist and a physiotherapist with training in musculoskeletal imaging. Test-retest reliability was assessed by comparing scores assigned by the physiotherapist to images recorded at the two sessions. The minimum detectable change (MDC) was calculated from the test-retest reliability data. ICC values for inter-rater reliability ranged from 0.35 (95% CI: 0.05, 0.60) for fibrillar disruption to 0.77 (0.55, 0.88) for overall greyscale score, and 0.89 (0.79, 0.95) for hyperaemia. Test-retest reliability ranged from 0.70 (0.48, 0.84) for tendon thickening to 0.82 (0.66, 0.90) for overall greyscale score and 0.86 (0.73, 0.93) for calcification. The MDC for the greyscale total score was 2.0/12 and for the hyperaemia score was 1.1/5. The sonographic scoring system used in this study may be used reliably to quantify tendon abnormalities and change over time. A relatively inexperienced imager can conduct the assessment and use the rating scales reliably.

  16. Design and reliability of a didactic inphographic rubric assessment

    OpenAIRE

    Guzmán-cedillo, Yunuen Ixchel

    2017-01-01

    The objective of this study is to describe design, validity process and reliability of a rubric assessment to evaluate didactic infographics quality. Participants were fifteen judges who participate in different moments of elaboration rubric process; it was made in three process phases: design, settings and reliability determination. Content validity was obtained by percentage agreement between 3 judges by component of the rubric; likewise a Krippendorff’s alpha were applied (a = .710) in pi...

  17. Reliability of histologic assessment in patients with eosinophilic oesophagitis.

    Science.gov (United States)

    Warners, M J; Ambarus, C A; Bredenoord, A J; Verheij, J; Lauwers, G Y; Walsh, J C; Katzka, D A; Nelson, S; van Viegen, T; Furuta, G T; Gupta, S K; Stitt, L; Zou, G; Parker, C E; Shackelton, L M; D Haens, G R; Sandborn, W J; Dellon, E S; Feagan, B G; Collins, M H; Jairath, V; Pai, R K

    2018-04-01

    The validity of the eosinophilic oesophagitis (EoE) histologic scoring system (EoEHSS) has been demonstrated, but only preliminary reliability data exist. Formally assess the reliability of the EoEHSS and additional histologic features. Four expert gastrointestinal pathologists independently reviewed slides from adult patients with EoE (N = 45) twice, in random order, using standardised training materials and scoring conventions for the EoEHSS and additional histologic features agreed upon during a modified Delphi process. Intra- and inter-rater reliability for scoring the EoEHSS, a visual analogue scale (VAS) of overall histopathologic disease severity, and additional histologic features were assessed using intra-class correlation coefficients (ICCs). Almost perfect intra-rater reliability was observed for the composite EoEHSS scores and the VAS. Inter-rater reliability was also almost perfect for the composite EoEHSS scores and substantial for the VAS. Of the EoEHSS items, eosinophilic inflammation was associated with the highest ICC estimates and consistent with almost perfect intra- and inter-rater reliability. With the exception of dyskeratotic epithelial cells and surface epithelial alteration, ICC estimates for the remaining EoEHSS items were above the benchmarks for substantial intra-rater, and moderate inter-rater reliability. Estimation of peak eosinophil count and number of lamina propria eosinophils were associated with the highest ICC estimates among the exploratory items. The composite EoEHSS and most component items are associated with substantial reliability when assessed by central pathologists. Future studies should assess responsiveness of the score to change after a therapeutic intervention to facilitate its use in clinical trials. © 2018 John Wiley & Sons Ltd.

  18. Critical Assessment of the Foundations of Power Transmission and Distribution Reliability Metrics and Standards.

    Science.gov (United States)

    Nateghi, Roshanak; Guikema, Seth D; Wu, Yue Grace; Bruss, C Bayan

    2016-01-01

    The U.S. federal government regulates the reliability of bulk power systems, while the reliability of power distribution systems is regulated at a state level. In this article, we review the history of regulating electric service reliability and study the existing reliability metrics, indices, and standards for power transmission and distribution networks. We assess the foundations of the reliability standards and metrics, discuss how they are applied to outages caused by large exogenous disturbances such as natural disasters, and investigate whether the standards adequately internalize the impacts of these events. Our reflections shed light on how existing standards conceptualize reliability, question the basis for treating large-scale hazard-induced outages differently from normal daily outages, and discuss whether this conceptualization maps well onto customer expectations. We show that the risk indices for transmission systems used in regulating power system reliability do not adequately capture the risks that transmission systems are prone to, particularly when it comes to low-probability high-impact events. We also point out several shortcomings associated with the way in which regulators require utilities to calculate and report distribution system reliability indices. We offer several recommendations for improving the conceptualization of reliability metrics and standards. We conclude that while the approaches taken in reliability standards have made considerable advances in enhancing the reliability of power systems and may be logical from a utility perspective during normal operation, existing standards do not provide a sufficient incentive structure for the utilities to adequately ensure high levels of reliability for end-users, particularly during large-scale events. © 2015 Society for Risk Analysis.

  19. The reliability of the Hendrich Fall Risk Model in a geriatric hospital.

    Science.gov (United States)

    Heinze, Cornelia; Halfens, Ruud; Dassen, Theo

    2008-12-01

    Aims and objectives.  The purpose of this study was to test the interrater reliability of the Hendrich Fall Risk Model, an instrument to identify patients in a hospital setting with a high risk of falling. Background.  Falls are a serious problem in older patients. Valid and reliable fall risk assessment tools are required to identify high-risk patients and to take adequate preventive measures. Methods.  Seventy older patients were independently and simultaneously assessed by six pairs of raters made up of nursing staff members. Consensus estimates were calculated using simple percentage agreement and consistency estimates using Spearman's rho and intra class coefficient. Results.  Percentage agreement ranged from 0.70 to 0.92 between the six pairs of raters. Spearman's rho coefficients were between 0.54 and 0.80 and the intra class coefficients were between 0.46 and 0.92. Conclusions.  Whereas some pairs of raters obtained considerable interobserver agreement and internal consistency, the others did not. Therefore, it is concluded that the Hendrich Fall Risk Model is not a reliable instrument. The use of more unambiguous operationalized items is preferred. Relevance to clinical practice.  In practice, well operationalized fall risk assessment tools are necessary. Observer agreement should always be investigated after introducing a standardized measurement tool. © 2008 The Authors. Journal compilation © 2008 Blackwell Publishing Ltd.

  20. Reliability of a single objective measure in assessing sleepiness.

    Science.gov (United States)

    Sunwoo, Bernie Y; Jackson, Nicholas; Maislin, Greg; Gurubhagavatula, Indira; George, Charles F; Pack, Allan I

    2012-01-01

    To evaluate reliability of single objective tests in assessing sleepiness. Subjects who completed polysomnography underwent a 4-nap multiple sleep latency test (MSLT) the following day. Prior to each nap opportunity on MSLT, subjects performed the psychomotor vigilance test (PVT) and divided attention driving task (DADT). Results of single versus multiple test administrations were compared using the intraclass correlation coefficient (ICC) and adjusted for test administration order effects to explore time of day effects. Measures were explored as continuous and binary (i.e., impaired or not impaired). Community-based sample evaluated at a tertiary, university-based sleep center. 372 adult commercial vehicle operators oversampled for increased obstructive sleep apnea risk. N/A. AS CONTINUOUS MEASURES, ICC WERE AS FOLLOWS: MSLT 0.45, PVT median response time 0.69, PVT number of lapses 0.51, 10-min DADT tracking error 0.87, 20-min DADT tracking error 0.90. Based on binary outcomes, ICC were: MSLT 0.63, PVT number of lapses 0.85, 10-min DADT 0.95, 20-min DADT 0.96. Statistically significant time of day effects were seen in both the MSLT and PVT but not the DADT. Correlation between ESS and different objective tests was strongest for MSLT, range [-0.270 to -0.195] and persisted across all time points. Single DADT and PVT administrations are reliable measures of sleepiness. A single MSLT administration can reasonably discriminate individuals with MSL < 8 minutes. These results support the use of a single administration of some objective tests of sleepiness when performed under controlled conditions in routine clinical care.

  1. Interrater reliability of Violence Risk Appraisal Guide scores provided in Canadian criminal proceedings.

    Science.gov (United States)

    Edens, John F; Penson, Brittany N; Ruchensky, Jared R; Cox, Jennifer; Smith, Shannon Toney

    2016-12-01

    Published research suggests that most violence risk assessment tools have relatively high levels of interrater reliability, but recent evidence of inconsistent scores among forensic examiners in adversarial settings raises concerns about the "field reliability" of such measures. This study specifically examined the reliability of Violence Risk Appraisal Guide (VRAG) scores in Canadian criminal cases identified in the legal database, LexisNexis. Over 250 reported cases were located that made mention of the VRAG, with 42 of these cases containing 2 or more scores that could be submitted to interrater reliability analyses. Overall, scores were skewed toward higher risk categories. The intraclass correlation (ICCA1) was .66, with pairs of forensic examiners placing defendants into the same VRAG risk "bin" in 68% of the cases. For categorical risk statements (i.e., low, moderate, high), examiners provided converging assessment results in most instances (86%). In terms of potential predictors of rater disagreement, there was no evidence for adversarial allegiance in our sample. Rater disagreement in the scoring of 1 VRAG item (Psychopathy Checklist-Revised; Hare, 2003), however, strongly predicted rater disagreement in the scoring of the VRAG (r = .58). (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  2. Assessment of technical risks

    Energy Technology Data Exchange (ETDEWEB)

    Jaeger, T A [Bundesanstalt fuer Materialpruefung, Berlin (Germany, F.R.)

    1978-01-01

    The safety of technical systems is so difficult to assess because the concept 'risk' contains technical-scientific factors as well as components of individual and social psychology. Immediate or short-term hazards of human life as i.e. caused by the operation of industrial plants and mediate and thus long-term hazards have to be distinguished. Characteristic for the second hazard groups is the great time-lag before the effect takes place. Thus a causal relationship can be recognized only late and not definitely. Even when the causes have been obviated the effects still show. The development of a systems-analytical model as a basis of decisive processes for the introduction of highly endangered large-scale technologies seems particularly difficult. A starting point for the quantification of the risk can still be seen in the product of the probability of realization and the extent of the damage. Public opinion, however, does not base its evaluations on an objective concept of risk but tends to have an attitude of aversion against great and disastrous accidents. On the other hand, plenty of slight accidents are accepted much more easily, even when the amount of deadly victims from accidents reaches dimensions beyond those of the rare large-scale accidents. Here, mostly the damage possible but not the probability of its occurence is seen, let alone the general use of the new technology. The value of the mathematical models for estimating risks is mainly due to the fact that they are able to clear up decisions.

  3. The Reliability of EMU FIscal Indicators: Risks and Safeguards

    OpenAIRE

    Fabrizio Balassone; Daniele Franco; Stefania Zotteri

    2007-01-01

    The reliability of EMU�s fiscal indicators has been questioned by recent episodes of large upward deficit revisions. This paper discusses the causes of such revisions in order to identify ways to improve monitoring. The computation of EMU�s deficit indicator involves the assessment of accrued revenue and expenditure and the identification of transactions in financial assets. Both can open margins for opportunistic accounting. However, crosschecks between deficit and changes in gross nomin...

  4. Reliable and valid assessment of Lichtenstein hernia repair skills

    DEFF Research Database (Denmark)

    Carlsen, C G; Lindorff Larsen, Karen; Funch-Jensen, P

    2014-01-01

    PURPOSE: Lichtenstein hernia repair is a common surgical procedure and one of the first procedures performed by a surgical trainee. However, formal assessment tools developed for this procedure are few and sparsely validated. The aim of this study was to determine the reliability and validity...... of an assessment tool designed to measure surgical skills in Lichtenstein hernia repair. METHODS: Key issues were identified through a focus group interview. On this basis, an assessment tool with eight items was designed. Ten surgeons and surgical trainees were video recorded while performing Lichtenstein hernia...... a significant difference between the three groups which indicates construct validity, p skills can be assessed blindly by a single rater in a reliable and valid fashion with the new procedure-specific assessment tool. We recommend this tool for future assessment...

  5. Assessment of structural reliability of precast concrete buildings

    Directory of Open Access Journals (Sweden)

    Koyankin Alexandr

    2018-01-01

    Full Text Available Precast housing construction is currently being under rapid development, however, reliability of building structures made from precast reinforced concrete cannot be assessed rationally due to insufficient research data on that subject. In this regard, experimental and numerical studies were conducted to assess structural reliability of precast buildings as described in the given paper. Experimental studies of full-scale and model samples were conducted; numerical studies were held based on finite element models using “Lira” software. The objects under study included fragment of flooring of a building under construction, full-size fragment of flooring, full-scale models of precast cross-beams-to-columns joints and joints between hollow-core floor slabs and precast and cast-in-place cross-beams. Conducted research enabled to perform an objective assessment of structural reliability of precast buildings.

  6. A new measurement of workload in Web application reliability assessment

    Directory of Open Access Journals (Sweden)

    CUI Xia

    2015-02-01

    Full Text Available Web application has been popular in various fields of social life.It becomes more and more important to study the reliability of Web application.In this paper the definition of Web application failure is firstly brought out,and then the definition of Web application reliability.By analyzing data in the IIS server logs and selecting corresponding usage and information delivery failure data,the paper study the feasibility of Web application reliability assessment from the perspective of Web software system based on IIS server logs.Because the usage for a Web site often has certain regularity,a new measurement of workload in Web application reliability assessment is raised.In this method,the unit is removed by weighted average technique;and the weights are assessed by setting objective function and optimization.Finally an experiment was raised for validation.The experiment result shows the assessment of Web application reliability base on the new workload is better.

  7. Risk assessment and risk management of mycotoxins.

    Science.gov (United States)

    2012-01-01

    Risk assessment is the process of quantifying the magnitude and exposure, or probability, of a harmful effect to individuals or populations from certain agents or activities. Here, we summarize the four steps of risk assessment: hazard identification, dose-response assessment, exposure assessment, and risk characterization. Risk assessments using these principles have been conducted on the major mycotoxins (aflatoxins, fumonisins, ochratoxin A, deoxynivalenol, and zearalenone) by various regulatory agencies for the purpose of setting food safety guidelines. We critically evaluate the impact of these risk assessment parameters on the estimated global burden of the associated diseases as well as the impact of regulatory measures on food supply and international trade. Apart from the well-established risk posed by aflatoxins, many uncertainties still exist about risk assessments for the other major mycotoxins, often reflecting a lack of epidemiological data. Differences exist in the risk management strategies and in the ways different governments impose regulations and technologies to reduce levels of mycotoxins in the food-chain. Regulatory measures have very little impact on remote rural and subsistence farming communities in developing countries, in contrast to developed countries, where regulations are strictly enforced to reduce and/or remove mycotoxin contamination. However, in the absence of the relevant technologies or the necessary infrastructure, we highlight simple intervention practices to reduce mycotoxin contamination in the field and/or prevent mycotoxin formation during storage.

  8. Reliability Assessment and Reliability-Based Inspection and Maintenance of Offshore Wind Turbines

    DEFF Research Database (Denmark)

    Ramirez, José Rangel

    actions are the most relevant and effective means of control of deterioration. The risk-based inspection planning methodology, based on Bayesian decision theory, represents an important tool to identify the suitable strategy to inspect and control the deterioration in structures such as offshore wind...... performance during the life cycle. The deterioration processes, such as fatigue and corrosion, are typically affecting offshore structural systems. This damage decreases the system performance and increases the risk of failure, thus not fulfilling the established safety criteria. Inspection and maintenance...... to their offshore location, no pollution risks and low human risks since they are unmanned. This allows the allocation of lower reliability level compared to e.g. oil & gas installations. With the incursion to water depths between 20 and 50 meters, the use of jacket and tripod structures represents a feasible...

  9. ASSESSING AND COMBINING RELIABILITY OF PROTEIN INTERACTION SOURCES

    Science.gov (United States)

    LEACH, SONIA; GABOW, AARON; HUNTER, LAWRENCE; GOLDBERG, DEBRA S.

    2008-01-01

    Integrating diverse sources of interaction information to create protein networks requires strategies sensitive to differences in accuracy and coverage of each source. Previous integration approaches calculate reliabilities of protein interaction information sources based on congruity to a designated ‘gold standard.’ In this paper, we provide a comparison of the two most popular existing approaches and propose a novel alternative for assessing reliabilities which does not require a gold standard. We identify a new method for combining the resultant reliabilities and compare it against an existing method. Further, we propose an extrinsic approach to evaluation of reliability estimates, considering their influence on the downstream tasks of inferring protein function and learning regulatory networks from expression data. Results using this evaluation method show 1) our method for reliability estimation is an attractive alternative to those requiring a gold standard and 2) the new method for combining reliabilities is less sensitive to noise in reliability assignments than the similar existing technique. PMID:17990508

  10. Caries risk assessment

    DEFF Research Database (Denmark)

    Mejàre, I; Axelsson, S; Dahlén, G

    2014-01-01

    OBJECTIVE: To assess the ability of multivariate models and single factors to correctly identify future caries development in pre-school children and schoolchildren/adolescents. STUDY DESIGN: A systematic literature search for relevant papers was conducted with pre-determined inclusion criteria...... predictors, baseline caries experience had moderate/good accuracy in pre-school children and limited accuracy in schoolchildren/adolescents. The period of highest risk for caries incidence in permanent teeth was the first few years after tooth eruption. In general, the quality of evidence was limited....... CONCLUSIONS: Multivariate models and baseline caries prevalence performed better in pre-school children than in schoolchildren/adolescents. Baseline caries prevalence was the most accurate single predictor in all age groups. The heterogeneity of populations, models, outcome criteria, measures and reporting...

  11. Assessment of the reliability of ultrasonic inspection methods

    International Nuclear Information System (INIS)

    Haines, N.F.; Langston, D.B.; Green, A.J.; Wilson, R.

    1982-01-01

    The reliability of NDT techniques has remained an open question for many years. A reliable technique may be defined as one that, when rigorously applied by a number of inspection teams, consistently finds then correctly sizes all defects of concern. In this paper we report an assessment of the reliability of defect detection by manual ultrasonic methods applied to the inspection of thick section pressure vessel weldments. Initially we consider the available data relating to the inherent physical capabilities of ultrasonic techniques to detect cracks in weldment and then, independently, we assess the likely variability in team to team performance when several teams are asked to follow the same specified test procedure. The two aspects of 'capability' and 'variability' are brought together to provide quantitative estimates of the overall reliability of ultrasonic inspection of thick section pressure vessel weldments based on currently existing data. The final section of the paper considers current research programmes on reliability and presents a view on how these will help to further improve NDT reliability. (author)

  12. Reliable and valid assessment of performance in thoracoscopy

    DEFF Research Database (Denmark)

    Konge, Lars; Lehnert, Per; Hansen, Henrik Jessen

    2012-01-01

    BACKGROUND: As we move toward competency-based education in medicine, we have lagged in developing competency-based evaluation methods. In the era of minimally invasive surgery, there is a need for a reliable and valid tool dedicated to measure competence in video-assisted thoracoscopic surgery....... The purpose of this study is to create such an assessment tool, and to explore its reliability and validity. METHODS: An expert group of physicians created an assessment tool consisting of 10 items rated on a five-point rating scale. The following factors were included: economy and confidence of movement...

  13. Reliability assessment for safety critical systems by statistical random testing

    International Nuclear Information System (INIS)

    Mills, S.E.

    1995-11-01

    In this report we present an overview of reliability assessment for software and focus on some basic aspects of assessing reliability for safety critical systems by statistical random testing. We also discuss possible deviations from some essential assumptions on which the general methodology is based. These deviations appear quite likely in practical applications. We present and discuss possible remedies and adjustments and then undertake applying this methodology to a portion of the SDS1 software. We also indicate shortcomings of the methodology and possible avenues to address to follow to address these problems. (author). 128 refs., 11 tabs., 31 figs

  14. Reliability assessment for safety critical systems by statistical random testing

    Energy Technology Data Exchange (ETDEWEB)

    Mills, S E [Carleton Univ., Ottawa, ON (Canada). Statistical Consulting Centre

    1995-11-01

    In this report we present an overview of reliability assessment for software and focus on some basic aspects of assessing reliability for safety critical systems by statistical random testing. We also discuss possible deviations from some essential assumptions on which the general methodology is based. These deviations appear quite likely in practical applications. We present and discuss possible remedies and adjustments and then undertake applying this methodology to a portion of the SDS1 software. We also indicate shortcomings of the methodology and possible avenues to address to follow to address these problems. (author). 128 refs., 11 tabs., 31 figs.

  15. Methods of risk assessment

    International Nuclear Information System (INIS)

    Jones, D.R.

    1981-01-01

    The subject is discussed under the headings: introduction (identification, quantification of risk); some approaches to risk evaluation (use of the 'no risk' principle; the 'acceptable risk' method; risk balancing; comparison of risks, benefits and other costs); cost benefit analysis; an alternative approach (tabulation and display; description and reduction of the data table); identification of potential decision sets consistent with the constraints. Some references are made to nuclear power. (U.K.)

  16. Reliability assessment of complex electromechanical systems under epistemic uncertainty

    International Nuclear Information System (INIS)

    Mi, Jinhua; Li, Yan-Feng; Yang, Yuan-Jian; Peng, Weiwen; Huang, Hong-Zhong

    2016-01-01

    The appearance of macro-engineering and mega-project have led to the increasing complexity of modern electromechanical systems (EMSs). The complexity of the system structure and failure mechanism makes it more difficult for reliability assessment of these systems. Uncertainty, dynamic and nonlinearity characteristics always exist in engineering systems due to the complexity introduced by the changing environments, lack of data and random interference. This paper presents a comprehensive study on the reliability assessment of complex systems. In view of the dynamic characteristics within the system, it makes use of the advantages of the dynamic fault tree (DFT) for characterizing system behaviors. The lifetime of system units can be expressed as bounded closed intervals by incorporating field failures, test data and design expertize. Then the coefficient of variation (COV) method is employed to estimate the parameters of life distributions. An extended probability-box (P-Box) is proposed to convey the present of epistemic uncertainty induced by the incomplete information about the data. By mapping the DFT into an equivalent Bayesian network (BN), relevant reliability parameters and indexes have been calculated. Furthermore, the Monte Carlo (MC) simulation method is utilized to compute the DFT model with consideration of system replacement policy. The results show that this integrated approach is more flexible and effective for assessing the reliability of complex dynamic systems. - Highlights: • A comprehensive study on the reliability assessment of complex system is presented. • An extended probability-box is proposed to convey the present of epistemic uncertainty. • The dynamic fault tree model is built. • Bayesian network and Monte Carlo simulation methods are used. • The reliability assessment of a complex electromechanical system is performed.

  17. Reliable and valid assessment of Lichtenstein hernia repair skills.

    Science.gov (United States)

    Carlsen, C G; Lindorff-Larsen, K; Funch-Jensen, P; Lund, L; Charles, P; Konge, L

    2014-08-01

    Lichtenstein hernia repair is a common surgical procedure and one of the first procedures performed by a surgical trainee. However, formal assessment tools developed for this procedure are few and sparsely validated. The aim of this study was to determine the reliability and validity of an assessment tool designed to measure surgical skills in Lichtenstein hernia repair. Key issues were identified through a focus group interview. On this basis, an assessment tool with eight items was designed. Ten surgeons and surgical trainees were video recorded while performing Lichtenstein hernia repair, (four experts, three intermediates, and three novices). The videos were blindly and individually assessed by three raters (surgical consultants) using the assessment tool. Based on these assessments, validity and reliability were explored. The internal consistency of the items was high (Cronbach's alpha = 0.97). The inter-rater reliability was very good with an intra-class correlation coefficient (ICC) = 0.93. Generalizability analysis showed a coefficient above 0.8 even with one rater. The coefficient improved to 0.92 if three raters were used. One-way analysis of variance found a significant difference between the three groups which indicates construct validity, p fashion with the new procedure-specific assessment tool. We recommend this tool for future assessment of trainees performing Lichtenstein hernia repair to ensure that the objectives of competency-based surgical training are met.

  18. 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.)

  19. Time-variant reliability assessment through equivalent stochastic process transformation

    International Nuclear Information System (INIS)

    Wang, Zequn; Chen, Wei

    2016-01-01

    Time-variant reliability measures the probability that an engineering system successfully performs intended functions over a certain period of time under various sources of uncertainty. In practice, it is computationally prohibitive to propagate uncertainty in time-variant reliability assessment based on expensive or complex numerical models. This paper presents an equivalent stochastic process transformation approach for cost-effective prediction of reliability deterioration over the life cycle of an engineering system. To reduce the high dimensionality, a time-independent reliability model is developed by translating random processes and time parameters into random parameters in order to equivalently cover all potential failures that may occur during the time interval of interest. With the time-independent reliability model, an instantaneous failure surface is attained by using a Kriging-based surrogate model to identify all potential failure events. To enhance the efficacy of failure surface identification, a maximum confidence enhancement method is utilized to update the Kriging model sequentially. Then, the time-variant reliability is approximated using Monte Carlo simulations of the Kriging model where system failures over a time interval are predicted by the instantaneous failure surface. The results of two case studies demonstrate that the proposed approach is able to accurately predict the time evolution of system reliability while requiring much less computational efforts compared with the existing analytical approach. - Highlights: • Developed a new approach for time-variant reliability analysis. • Proposed a novel stochastic process transformation procedure to reduce the dimensionality. • Employed Kriging models with confidence-based adaptive sampling scheme to enhance computational efficiency. • The approach is effective for handling random process in time-variant reliability analysis. • Two case studies are used to demonstrate the efficacy

  20. Risk assessments ensure safer power

    Energy Technology Data Exchange (ETDEWEB)

    1982-02-19

    A growth industry is emerging devoted to the study and comparison of the economic, social and health risks posed by large industrial installations. Electricity generation is one area coming under particularly close scrutiny. Types of risk, ways of assessing risk and the difference between experts' analyses and the public perception of risk are given. An example of improved risk assessment helping to reduce deaths and injuries in coal mining is included.

  1. Quantitative risk assessment of digitalized safety systems

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Sung Min; Lee, Sang Hun; Kang, Hym Gook [KAIST, Daejeon (Korea, Republic of); Lee, Seung Jun [UNIST, Ulasn (Korea, Republic of)

    2016-05-15

    A report published by the U.S. National Research Council indicates that appropriate methods for assessing reliability are key to establishing the acceptability of digital instrumentation and control (I and C) systems in safety-critical plants such as NPPs. Since the release of this issue, the methodology for the probabilistic safety assessment (PSA) of digital I and C systems has been studied. However, there is still no widely accepted method. Kang and Sung found three critical factors for safety assessment of digital systems: detection coverage of fault-tolerant techniques, software reliability quantification, and network communication risk. In reality the various factors composing digitalized I and C systems are not independent of each other but rather closely connected. Thus, from a macro point of view, a method that can integrate risk factors with different characteristics needs to be considered together with the micro approaches to address the challenges facing each factor.

  2. Reliability of Instruments Measuring At-Risk and Problem Gambling Among Young Individuals

    DEFF Research Database (Denmark)

    Edgren, Robert; Castrén, Sari; Mäkelä, Marjukka

    2016-01-01

    This review aims to clarify which instruments measuring at-risk and problem gambling (ARPG) among youth are reliable and valid in light of reported estimates of internal consistency, classification accuracy, and psychometric properties. A systematic search was conducted in PubMed, Medline, and Psyc......Info covering the years 2009–2015. In total, 50 original research articles fulfilled the inclusion criteria: target age under 29 years, using an instrument designed for youth, and reporting a reliability estimate. Articles were evaluated with the revised Quality Assessment of Diagnostic Accuracy Studies tool....... Reliability estimates were reported for five ARPG instruments. Most studies (66%) evaluated the South Oaks Gambling Screen Revised for Adolescents. The Gambling Addictive Behavior Scale for Adolescents was the only novel instrument. In general, the evaluation of instrument reliability was superficial. Despite...

  3. Reliable and Valid Assessment of Point-of-care Ultrasonography

    DEFF Research Database (Denmark)

    Todsen, Tobias; Tolsgaard, Martin Grønnebæk; Olsen, Beth Härstedt

    2015-01-01

    physicians' OSAUS scores with diagnostic accuracy. RESULTS: The generalizability coefficient was high (0.81) and a D-study demonstrated that 1 assessor and 5 cases would result in similar reliability. The construct validity of the OSAUS scale was supported by a significant difference in the mean scores......OBJECTIVE: To explore the reliability and validity of the Objective Structured Assessment of Ultrasound Skills (OSAUS) scale for point-of-care ultrasonography (POC US) performance. BACKGROUND: POC US is increasingly used by clinicians and is an essential part of the management of acute surgical...... conditions. However, the quality of performance is highly operator-dependent. Therefore, reliable and valid assessment of trainees' ultrasonography competence is needed to ensure patient safety. METHODS: Twenty-four physicians, representing novices, intermediates, and experts in POC US, scanned 4 different...

  4. Defense Programs Transportation Risk Assessment

    International Nuclear Information System (INIS)

    Clauss, D.B.

    1994-01-01

    This paper provides an overview of the methodology used in a probabilistic transportation risk assessment conducted to assess the probabilities and consequences of inadvertent dispersal of radioactive materials arising from severe transportation accidents. The model was developed for the Defense Program Transportation Risk Assessment (DPTRA) study. The analysis incorporates several enhancements relative to previous risk assessments of hazardous materials transportation including newly-developed statistics on the frequencies and severities of tractor semitrailer accidents and detailed route characterization using the 1990 Census data

  5. Validity and inter-observer reliability of subjective hand-arm vibration assessments

    NARCIS (Netherlands)

    Coenen, P.; Formanoy, M.; Douwes, M.; Bosch, T.; Kraker, H. de

    2014-01-01

    Exposure to mechanical vibrations at work (e.g., due to handling powered tools) is a potential occupational risk as it may cause upper extremity complaints. However, reliable and valid assessment methods for vibration exposure at work are lacking. Measuring hand-arm vibration objectively is often

  6. 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...

  7. 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...

  8. Methodology for reliability, economic and environmental assessment of wave energy

    International Nuclear Information System (INIS)

    Thorpe, T.W.; Muirhead, S.

    1994-01-01

    As part of the Preliminary Actions in Wave Energy R and D for DG XII's Joule programme, methodologies were developed to facilitate assessment of the reliability, economics and environmental impact of wave energy. This paper outlines these methodologies, their limitations and areas requiring further R and D. (author)

  9. Reliable and Valid Assessment of Clinical Bronchoscopy Performance

    DEFF Research Database (Denmark)

    Konge, Lars; Larsen, Klaus Richter; Clementsen, Paul

    2012-01-01

    : The interrater reliability was high, with Cronbach's a = 0.86. Assessment of 3 bronchoscopies by a single rater had a generalizability coefficient of 0.84. The correlation between experience and performance was good (Pearson correlation = 0.76). There were significant differences between the groups for all...

  10. Assessment of the Reliability of Concrete Slab Bridges

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle; Jensen, F. M.; Middleton, C. R.

    This paper is based on research performed for the Highways Agency, London, UK under the project DPU/9/44 "Revision of Bridge Assessment Rules Based on Whole Life Performance: Concrete Bridges". It contains details of a methodology which can be used to generate Whole Life (WL) reliability profiles....

  11. Assessment of reliability of Greulich and Pyle (gp) method for ...

    African Journals Online (AJOL)

    Background: Greulich and Pyle standards are the most widely used age estimation standards all over the world. The applicability of the Greulich and Pyle standards to populations which differ from their reference population is often questioned. This study aimed to assess the reliability of Greulich and Pyle (GP) method for ...

  12. Reliability of scored patient generated subjective global assessment ...

    African Journals Online (AJOL)

    Objective: Establish the reliability of the scored Patient Generated-Subjective Global Assessment (PG-SGA) in determining nutritional status among Antiretroviral Therapy (ART) naive HIV-infected adults. Methods: A descriptive, cross sectional study among outpatient medical clinics, in The AIDS Support Organization ...

  13. Qualification Users' Perceptions and Experiences of Assessment Reliability

    Science.gov (United States)

    Chamberlain, Suzanne

    2013-01-01

    This paper presents the findings of a study designed to explore qualification users' perceptions and experiences of reliability in the context of national assessment outcomes in England. The study consisted of 17 focus groups conducted across six sectors of qualification users: students, teachers, trainee teachers, job-seekers, employers and…

  14. Reliability of medical audit in quality assessment of medical care

    Directory of Open Access Journals (Sweden)

    Camacho Luiz Antonio Bastos

    1996-01-01

    Full Text Available Medical audit of hospital records has been a major component of quality of care assessment, although physician judgment is known to have low reliability. We estimated interrater agreement of quality assessment in a sample of patients with cardiac conditions admitted to an American teaching hospital. Physician-reviewers used structured review methods designed to improve quality assessment based on judgment. Chance-corrected agreement for the items considered more relevant to process and outcome of care ranged from low to moderate (0.2 to 0.6, depending on the review item and the principal diagnoses and procedures the patients underwent. Results from several studies seem to converge on this point. Comparisons among different settings should be made with caution, given the sensitivity of agreement measurements to prevalence rates. Reliability of review methods in their current stage could be improved by combining the assessment of two or more reviewers, and by emphasizing outcome-oriented events.

  15. A Reliability Assessment Method for the VHTR Safety Systems

    International Nuclear Information System (INIS)

    Lee, Hyung Sok; Jae, Moo Sung; Kim, Yong Wan

    2011-01-01

    The Passive safety system by very high temperature reactor which has attracted worldwide attention in the last century is the reliability safety system introduced for the improvement in the safety of the next generation nuclear power plant design. The Passive system functionality does not rely on an external source of energy, but on an intelligent use of the natural phenomena, such as gravity, conduction and radiation, which are always present. Because of these features, it is difficult to evaluate the passive safety on the risk analysis methodology having considered the existing active system failure. Therefore new reliability methodology has to be considered. In this study, the preliminary evaluation and conceptualization are tried, applying the concept of the load and capacity from the reliability physics model, designing the new passive system analysis methodology, and the trial applying to paper plant.

  16. Systems Reliability Framework for Surface Water Sustainability and Risk Management

    Science.gov (United States)

    Myers, J. R.; Yeghiazarian, L.

    2016-12-01

    With microbial contamination posing a serious threat to the availability of clean water across the world, it is necessary to develop a framework that evaluates the safety and sustainability of water systems in respect to non-point source fecal microbial contamination. The concept of water safety is closely related to the concept of failure in reliability theory. In water quality problems, the event of failure can be defined as the concentration of microbial contamination exceeding a certain standard for usability of water. It is pertinent in watershed management to know the likelihood of such an event of failure occurring at a particular point in space and time. Microbial fate and transport are driven by environmental processes taking place in complex, multi-component, interdependent environmental systems that are dynamic and spatially heterogeneous, which means these processes and therefore their influences upon microbial transport must be considered stochastic and variable through space and time. A physics-based stochastic model of microbial dynamics is presented that propagates uncertainty using a unique sampling method based on artificial neural networks to produce a correlation between watershed characteristics and spatial-temporal probabilistic patterns of microbial contamination. These results are used to address the question of water safety through several sustainability metrics: reliability, vulnerability, resilience and a composite sustainability index. System reliability is described uniquely though the temporal evolution of risk along watershed points or pathways. Probabilistic resilience describes how long the system is above a certain probability of failure, and the vulnerability metric describes how the temporal evolution of risk changes throughout a hierarchy of failure levels. Additionally our approach allows for the identification of contributions in microbial contamination and uncertainty from specific pathways and sources. We expect that this

  17. The risk of bias in systematic reviews tool showed fair reliability and good construct validity.

    Science.gov (United States)

    Bühn, Stefanie; Mathes, Tim; Prengel, Peggy; Wegewitz, Uta; Ostermann, Thomas; Robens, Sibylle; Pieper, Dawid

    2017-11-01

    There is a movement from generic quality checklists toward a more domain-based approach in critical appraisal tools. This study aimed to report on a first experience with the newly developed risk of bias in systematic reviews (ROBIS) tool and compare it with A Measurement Tool to Assess Systematic Reviews (AMSTAR), that is, the most common used tool to assess methodological quality of systematic reviews while assessing validity, reliability, and applicability. Validation study with four reviewers based on 16 systematic reviews in the field of occupational health. Interrater reliability (IRR) of all four raters was highest for domain 2 (Fleiss' kappa κ = 0.56) and lowest for domain 4 (κ = 0.04). For ROBIS, median IRR was κ = 0.52 (range 0.13-0.88) for the experienced pair of raters compared to κ = 0.32 (range 0.12-0.76) for the less experienced pair of raters. The percentage of "yes" scores of each review of ROBIS ratings was strongly correlated with the AMSTAR ratings (r s  = 0.76; P = 0.01). ROBIS has fair reliability and good construct validity to assess the risk of bias in systematic reviews. More validation studies are needed to investigate reliability and applicability, in particular. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Risk assessment for halogenated solvents

    International Nuclear Information System (INIS)

    Travis, C.C.

    1988-01-01

    A recent development in the cancer risk area is the advent of biologically based pharmacokinetic and pharmacodynamic models. These models allow for the incorporation of biological and mechanistic data into the risk assessment process. These advances will not only improve the risk assessment process for halogenated solvents but will stimulate and guide basic research in the biological area

  19. Risk Factor Assessment Branch (RFAB)

    Science.gov (United States)

    The Risk Factor Assessment Branch (RFAB) focuses on the development, evaluation, and dissemination of high-quality risk factor metrics, methods, tools, technologies, and resources for use across the cancer research continuum, and the assessment of cancer-related risk factors in the population.

  20. 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

  1. Risk assessment techniques for industrial installations

    International Nuclear Information System (INIS)

    Croitoru, C.; Dumitrescu, M.; Preda, I.; Stefanescu, I.; Titescu, G.

    1995-01-01

    This paper presents a risk analysis which concerns the following stages: identification of the initiation events, evaluation of the occurrence frequency of different accident sequences, assessment of human, economical, and environmental consequences, risk assessment and management. The study of the accident sequences subsequent to an initiation event was achieved by the event tree method. Also, there were developed methods based on mathematical models of installations which take into account reliability data, data concerning the exploitation history, and data referring to the human factor effects in the installation operation. These methods were used for the determination of occurrence frequencies of hydrogen sulfide emission accidents in the heavy water production installations

  2. Observer reliability in assessing placental maturity by histology.

    OpenAIRE

    Khong, T Y; Staples, A; Bendon, R W; Chambers, H M; Gould, S J; Knowles, S; Shen-Schwarz, S

    1995-01-01

    AIMS--To evaluate the ability of five experienced perinatal pathologists to assess placental maturity reliably by histology. METHODS--Twenty four haematoxylin and eosin slides, six each from placentas of 27, 31, 35, and 39 weeks' gestation, were circulated to five pathologists on three separate occasions. The slides were labelled with the correct or incorrect gestational ages. RESULTS--The mean absolute error over all 360 readings was 2.72 weeks. Only 54% of the slides were assessed within tw...

  3. Risk-based methods for reliability investments in electric power distribution systems

    Energy Technology Data Exchange (ETDEWEB)

    Alvehag, Karin

    2011-07-01

    Society relies more and more on a continuous supply of electricity. However, while under investments in reliability lead to an unacceptable number of power interruptions, over investments result in too high costs for society. To give incentives for a socio economically optimal level of reliability, quality regulations have been adopted in many European countries. These quality regulations imply new financial risks for the distribution system operator (DSO) since poor reliability can reduce the allowed revenue for the DSO and compensation may have to be paid to affected customers. This thesis develops a method for evaluating the incentives for reliability investments implied by different quality regulation designs. The method can be used to investigate whether socio economically beneficial projects are also beneficial for a profit-maximizing DSO subject to a particular quality regulation design. To investigate which reinvestment projects are preferable for society and a DSO, risk-based methods are developed. With these methods, the probability of power interruptions and the consequences of these can be simulated. The consequences of interruptions for the DSO will to a large extent depend on the quality regulation. The consequences for the customers, and hence also society, will depend on factors such as the interruption duration and time of occurrence. The proposed risk-based methods consider extreme outage events in the risk assessments by incorporating the impact of severe weather, estimating the full probability distribution of the total reliability cost, and formulating a risk-averse strategy. Results from case studies performed show that quality regulation design has a significant impact on reinvestment project profitability for a DSO. In order to adequately capture the financial risk that the DSO is exposed to, detailed riskbased methods, such as the ones developed in this thesis, are needed. Furthermore, when making investment decisions, a risk

  4. Inter-rater reliability of an observation-based ergonomics assessment checklist for office workers.

    Science.gov (United States)

    Pereira, Michelle Jessica; Straker, Leon Melville; Comans, Tracy Anne; Johnston, Venerina

    2016-12-01

    To establish the inter-rater reliability of an observation-based ergonomics assessment checklist for computer workers. A 37-item (38-item if a laptop was part of the workstation) comprehensive observational ergonomics assessment checklist comparable to government guidelines and up to date with empirical evidence was developed. Two trained practitioners assessed full-time office workers performing their usual computer-based work and evaluated the suitability of workstations used. Practitioners assessed each participant consecutively. The order of assessors was randomised, and the second assessor was blinded to the findings of the first. Unadjusted kappa coefficients between the raters were obtained for the overall checklist and subsections that were formed from question-items relevant to specific workstation equipment. Twenty-seven office workers were recruited. The inter-rater reliability between two trained practitioners achieved moderate to good reliability for all except one checklist component. This checklist has mostly moderate to good reliability between two trained practitioners. Practitioner Summary: This reliable ergonomics assessment checklist for computer workers was designed using accessible government guidelines and supplemented with up-to-date evidence. Employers in Queensland (Australia) can fulfil legislative requirements by using this reliable checklist to identify and subsequently address potential risk factors for work-related injury to provide a safe working environment.

  5. Reliability of the Hazelbaker Assessment Tool for Lingual Frenulum Function

    Directory of Open Access Journals (Sweden)

    James Jennifer P

    2006-03-01

    Full Text Available Abstract Background About 3% of infants are born with a tongue-tie which may lead to breastfeeding problems such as ineffective latch, painful attachment or poor weight gain. The Hazelbaker Assessment Tool for Lingual Frenulum Function (HATLFF has been developed to give a quantitative assessment of the tongue-tie and recommendation about frenotomy (release of the frenulum. The aim of this study was to assess the inter-rater reliability of the HATLFF. Methods Fifty-eight infants referred to the Breastfeeding Education and Support Services (BESS at The Royal Women's Hospital for assessment of tongue-tie and 25 control infants were assessed by two clinicians independently. Results The Appearance items received kappas between about 0.4 to 0.6, which represents "moderate" reliability. The first three Function items (lateralization, lift and extension of tongue had kappa values over 0.65 which indicates "substantial" agreement. The four Function items relating to infant sucking (spread, cupping, peristalsis and snapback received low kappa values with insignificant p values. There was 96% agreement between the two assessors on the recommendation for frenotomy (kappa 0.92, excellent agreement. The study found that the Function Score can be more simply assessed using only the first three function items (ie not scoring the sucking items, with a cut-off of ≤4 for recommendation of frenotomy. Conclusion We found that the HATLFF has a high reliability in a study of infants with tongue-tie and control infants

  6. HTGR accident and risk assessment

    International Nuclear Information System (INIS)

    Silady, F.A.; Everline, C.J.; Houghton, W.J.

    1982-01-01

    This paper is a synopsis of the high-temperature gas-cooled reactor probabilistic risk assessments (PRAs) performed by General Atomic Company. Principal topics presented include: HTGR safety assessments, peer interfaces, safety research, process gas explosions, quantitative safety goals, licensing applications of PRA, enhanced safety, investment risk assessments, and PRA design integration

  7. Nonspecialist Raters Can Provide Reliable Assessments of Procedural Skills

    DEFF Research Database (Denmark)

    Mahmood, Oria; Dagnæs, Julia; Bube, Sarah

    2018-01-01

    was significant (p Pearson's correlation of 0.77 for the nonspecialists and 0.75 for the specialists. The test-retest reliability showed the biggest difference between the 2 groups, 0.59 and 0.38 for the nonspecialist raters and the specialist raters, respectively (p ... was chosen as it is a simple procedural skill that is crucial to master in a resident urology program. RESULTS: The internal consistency of assessments was high, Cronbach's α = 0.93 and 0.95 for nonspecialist and specialist raters, respectively (p correlations). The interrater reliability...

  8. Quantitative reliability assessment for safety critical system software

    International Nuclear Information System (INIS)

    Chung, Dae Won; Kwon, Soon Man

    2005-01-01

    An essential issue in the replacement of the old analogue I and C to computer-based digital systems in nuclear power plants is the quantitative software reliability assessment. Software reliability models have been successfully applied to many industrial applications, but have the unfortunate drawback of requiring data from which one can formulate a model. Software which is developed for safety critical applications is frequently unable to produce such data for at least two reasons. First, the software is frequently one-of-a-kind, and second, it rarely fails. Safety critical software is normally expected to pass every unit test producing precious little failure data. The basic premise of the rare events approach is that well-tested software does not fail under normal routine and input signals, which means that failures must be triggered by unusual input data and computer states. The failure data found under the reasonable testing cases and testing time for these conditions should be considered for the quantitative reliability assessment. We will present the quantitative reliability assessment methodology of safety critical software for rare failure cases in this paper

  9. [Reliability and validity of the Braden Scale for predicting pressure sore risk].

    Science.gov (United States)

    Boes, C

    2000-12-01

    For more accurate and objective pressure sore risk assessment various risk assessment tools were developed mainly in the USA and Great Britain. The Braden Scale for Predicting Pressure Sore Risk is one such example. By means of a literature analysis of German and English texts referring to the Braden Scale the scientific control criteria reliability and validity will be traced and consequences for application of the scale in Germany will be demonstrated. Analysis of 4 reliability studies shows an exclusive focus on interrater reliability. Further, even though examination of 19 validity studies occurs in many different settings, such examination is limited to the criteria sensitivity and specificity (accuracy). The range of sensitivity and specificity level is 35-100%. The recommended cut off points rank in the field of 10 to 19 points. The studies prove to be not comparable with each other. Furthermore, distortions in these studies can be found which affect accuracy of the scale. The results of the here presented analysis show an insufficient proof for reliability and validity in the American studies. In Germany, the Braden scale has not yet been tested under scientific criteria. Such testing is needed before using the scale in different German settings. During the course of such testing, construction and study procedures of the American studies can be used as a basis as can the problems be identified in the analysis presented below.

  10. Information needs for risk assessment

    Energy Technology Data Exchange (ETDEWEB)

    DeRosa, C.T.; Choudhury, H.; Schoeny, R.S.

    1990-12-31

    Risk assessment can be thought of as a conceptual approach to bridge the gap between the available data and the ultimate goal of characterizing the risk or hazard associated with a particular environmental problem. To lend consistency to and to promote quality in the process, the US Environmental Protection Agency (EPA) published Guidelines for Risk Assessment of Carcinogenicity, Developmental Toxicity, Germ Cell Mutagenicity and Exposure Assessment, and Risk Assessment of Chemical Mixtures. The guidelines provide a framework for organizing the information, evaluating data, and for carrying out the risk assessment in a scientifically plausible manner. In the absence of sufficient scientific information or when abundant data are available, the guidelines provide alternative methodologies that can be employed in the risk assessment. 4 refs., 3 figs., 2 tabs.

  11. Evaluation of piping reliability and failure data for use in risk-based inspections of nuclear power plants

    Energy Technology Data Exchange (ETDEWEB)

    Vasconcelos, V. de; Soares, W.A.; Costa, A.C.L. da; Rabello, E.G.; Marques, R.O., E-mail: vasconv@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2016-07-01

    During operation of industrial facilities, components and systems can deteriorate over time, thus increasing the possibility of accidents. Risk-Based Inspection (RBI) involves inspection planning based on information about risks, through assessing of probability and consequence of failures. In-service inspections are used in nuclear power plants, in order to ensure reliable and safe operation. Traditional deterministic inspection approaches investigate generic degradation mechanisms on all systems. However, operating experience indicates that degradation occurs where there are favorable conditions for developing a specific mechanism. Inspections should be prioritized at these places. Risk-Informed In-service Inspections (RI-ISI) are types of RBI that use Probabilistic Safety Assessment results, increasing reliability and plant safety, and reducing radiation exposure. These assessments use both available generic reliability and failure data, as well as plant specific information. This paper proposes a method for evaluating piping reliability and failure data important for RI-ISI programs, as well as the techniques involved. (author)

  12. Evaluation of piping reliability and failure data for use in risk-based inspections of nuclear power plants

    International Nuclear Information System (INIS)

    Vasconcelos, V. de; Soares, W.A.; Costa, A.C.L. da; Rabello, E.G.; Marques, R.O.

    2016-01-01

    During operation of industrial facilities, components and systems can deteriorate over time, thus increasing the possibility of accidents. Risk-Based Inspection (RBI) involves inspection planning based on information about risks, through assessing of probability and consequence of failures. In-service inspections are used in nuclear power plants, in order to ensure reliable and safe operation. Traditional deterministic inspection approaches investigate generic degradation mechanisms on all systems. However, operating experience indicates that degradation occurs where there are favorable conditions for developing a specific mechanism. Inspections should be prioritized at these places. Risk-Informed In-service Inspections (RI-ISI) are types of RBI that use Probabilistic Safety Assessment results, increasing reliability and plant safety, and reducing radiation exposure. These assessments use both available generic reliability and failure data, as well as plant specific information. This paper proposes a method for evaluating piping reliability and failure data important for RI-ISI programs, as well as the techniques involved. (author)

  13. Exploration Health Risks: Probabilistic Risk Assessment

    Science.gov (United States)

    Rhatigan, Jennifer; Charles, John; Hayes, Judith; Wren, Kiley

    2006-01-01

    Maintenance of human health on long-duration exploration missions is a primary challenge to mission designers. Indeed, human health risks are currently the largest risk contributors to the risks of evacuation or loss of the crew on long-duration International Space Station missions. We describe a quantitative assessment of the relative probabilities of occurrence of the individual risks to human safety and efficiency during space flight to augment qualitative assessments used in this field to date. Quantitative probabilistic risk assessments will allow program managers to focus resources on those human health risks most likely to occur with undesirable consequences. Truly quantitative assessments are common, even expected, in the engineering and actuarial spheres, but that capability is just emerging in some arenas of life sciences research, such as identifying and minimize the hazards to astronauts during future space exploration missions. Our expectation is that these results can be used to inform NASA mission design trade studies in the near future with the objective of preventing the higher among the human health risks. We identify and discuss statistical techniques to provide this risk quantification based on relevant sets of astronaut biomedical data from short and long duration space flights as well as relevant analog populations. We outline critical assumptions made in the calculations and discuss the rationale for these. Our efforts to date have focussed on quantifying the probabilities of medical risks that are qualitatively perceived as relatively high risks of radiation sickness, cardiac dysrhythmias, medically significant renal stone formation due to increased calcium mobilization, decompression sickness as a result of EVA (extravehicular activity), and bone fracture due to loss of bone mineral density. We present these quantitative probabilities in order-of-magnitude comparison format so that relative risk can be gauged. We address the effects of

  14. High reliability flow system - an assessment of pump reliability and optimisation of the number of pumps

    International Nuclear Information System (INIS)

    Butterfield, J.M.

    1981-01-01

    A system is considered where a number of pumps operate in parallel. Normally, all pumps operate, driven by main motors fed from the grid. Each pump has a pony motor fed from an individual battery supply. Each pony motor is normally running, but not engaged to the pump shaft. On demand, e.g. failure of grid supplies, each pony motor is designed to clutch-in automatically when the pump speed falls to a specified value. The probability of all the pony motors failing to clutch-in on demand must be demonstrated with 95% confidence to be less than 10 -8 per demand. This assessment considers how the required reliability of pony motor drives might be demonstrated in practice and the implications on choice of the number of pumps at the design stage. The assessment recognises that not only must the system prove to be extremely reliable, but that demonstration that reliability is adequate must be done during plant commissioning, with practical limits on the amount of testing performed. It is concluded that a minimum of eight pony motors should be provided, eight pumps each with one pony motor (preferred) or five pumps each with two independent pony motors. A minimum of two diverse pony motor systems should be provided. (author)

  15. Reliability Assessment of Transformerless PV Inverters considering Mission Profiles

    Directory of Open Access Journals (Sweden)

    Yongheng Yang

    2015-01-01

    Full Text Available Due to the small volume and high efficiency, transformerless inverters have gained much popularity in grid-connected PV applications, where minimizing leakage current injection is mandatory. This can be achieved by either modifying the modulation schemes or adding extra power switching devices, resulting in an uneven distribution of the power losses on the switching devices. Consequently, the device thermal loading is redistributed and thus may alter the entire inverter reliability performance, especially under a long-term operation. In this consideration, this paper assesses the device reliability of three transformerless inverters under a yearly mission profile (i.e., solar irradiance and ambient temperature. The mission profile is translated to device thermal loading, which is used for lifetime prediction. Comparison results reveal the lifetime mismatches among the power switching devices operating under the same condition, which offers new thoughts for a robust design and a reliable operation of grid-connected transformerless PV inverters with high efficiency.

  16. Reliability-based assessment of polyethylene pipe creep lifetime

    International Nuclear Information System (INIS)

    Khelif, Rabia; Chateauneuf, Alaa; Chaoui, Kamel

    2007-01-01

    Lifetime management of underground pipelines is mandatory for safe hydrocarbon transmission and distribution systems. The use of high-density polyethylene tubes subjected to internal pressure, external loading and environmental variations requires a reliability study in order to define the service limits and the optimal operating conditions. In service, the time-dependent phenomena, especially creep, take place during the pipe lifetime, leading to significant strength reduction. In this work, the reliability-based assessment of pipe lifetime models is carried out, in order to propose a probabilistic methodology for lifetime model selection and to determine the pipe safety levels as well as the most important parameters for pipeline reliability. This study is enhanced by parametric analysis on pipe configuration, gas pressure and operating temperature

  17. Reliability-based assessment of polyethylene pipe creep lifetime

    Energy Technology Data Exchange (ETDEWEB)

    Khelif, Rabia [LaMI-UBP and IFMA, Campus de Clermont-Fd, Les Cezeaux, BP 265, 63175 Aubiere Cedex (France); LR3MI, Departement de Genie Mecanique, Universite Badji Mokhtar, BP 12, Annaba 23000 (Algeria)], E-mail: rabia.khelif@ifma.fr; Chateauneuf, Alaa [LGC-University Blaise Pascal, Campus des Cezeaux, BP 206, 63174 Aubiere Cedex (France)], E-mail: alaa.chateauneuf@polytech.univ-bpclermont.fr; Chaoui, Kamel [LR3MI, Departement de Genie Mecanique, Universite Badji Mokhtar, BP 12, Annaba 23000 (Algeria)], E-mail: chaoui@univ-annaba.org

    2007-12-15

    Lifetime management of underground pipelines is mandatory for safe hydrocarbon transmission and distribution systems. The use of high-density polyethylene tubes subjected to internal pressure, external loading and environmental variations requires a reliability study in order to define the service limits and the optimal operating conditions. In service, the time-dependent phenomena, especially creep, take place during the pipe lifetime, leading to significant strength reduction. In this work, the reliability-based assessment of pipe lifetime models is carried out, in order to propose a probabilistic methodology for lifetime model selection and to determine the pipe safety levels as well as the most important parameters for pipeline reliability. This study is enhanced by parametric analysis on pipe configuration, gas pressure and operating temperature.

  18. Validity and reliability of a questionnaire on knowledge of cardiovascular risk factors for use in Brazil

    Directory of Open Access Journals (Sweden)

    Marco Aurelio Lumertz Saffi

    2013-10-01

    Full Text Available Using a sample of patients with coronary artery disease, this methodological study aimed to conduct a cross-cultural adaptation and validation of a questionnaire on knowledge of cardiovascular risk factors (Q-FARCS, lifestyle changes, and treatment adherence for use in Brazil. The questionnaire has three scales: general knowledge of risk factors (RFs; specific knowledge of these RFs; and lifestyle changes achieved. Cross-cultural adaptation included translation, synthesis, back-translation, expert committee review, and pretesting. Face and content validity, reliability, and construct validity were measured. Cronbach’s alpha for the total sample (n = 240 was 0.75. Assessment of psychometric properties revealed adequate face and content validity, and the construct revealed seven components. It was concluded that the Brazilian version of Q-FARCS had adequate reliability and validity for the assessment of knowledge of cardiovascular RFs.

  19. Reliability and Validity Assessment of a Linear Position Transducer

    Science.gov (United States)

    Garnacho-Castaño, Manuel V.; López-Lastra, Silvia; Maté-Muñoz, José L.

    2015-01-01

    The objectives of the study were to determine the validity and reliability of peak velocity (PV), average velocity (AV), peak power (PP) and average power (AP) measurements were made using a linear position transducer. Validity was assessed by comparing measurements simultaneously obtained using the Tendo Weightlifting Analyzer Systemi and T-Force Dynamic Measurement Systemr (Ergotech, Murcia, Spain) during two resistance exercises, bench press (BP) and full back squat (BS), performed by 71 trained male subjects. For the reliability study, a further 32 men completed both lifts using the Tendo Weightlifting Analyzer Systemz in two identical testing sessions one week apart (session 1 vs. session 2). Intraclass correlation coefficients (ICCs) indicating the validity of the Tendo Weightlifting Analyzer Systemi were high, with values ranging from 0.853 to 0.989. Systematic biases and random errors were low to moderate for almost all variables, being higher in the case of PP (bias ±157.56 W; error ±131.84 W). Proportional biases were identified for almost all variables. Test-retest reliability was strong with ICCs ranging from 0.922 to 0.988. Reliability results also showed minimal systematic biases and random errors, which were only significant for PP (bias -19.19 W; error ±67.57 W). Only PV recorded in the BS showed no significant proportional bias. The Tendo Weightlifting Analyzer Systemi emerged as a reliable system for measuring movement velocity and estimating power in resistance exercises. The low biases and random errors observed here (mainly AV, AP) make this device a useful tool for monitoring resistance training. Key points This study determined the validity and reliability of peak velocity, average velocity, peak power and average power measurements made using a linear position transducer The Tendo Weight-lifting Analyzer Systemi emerged as a reliable system for measuring movement velocity and power. PMID:25729300

  20. [Forensic assessment of violence risk].

    Science.gov (United States)

    Pujol Robinat, Amadeo; Mohíno Justes, Susana; Gómez-Durán, Esperanza L

    2014-03-01

    Over the last 20 years there have been steps forward in the field of scientific research on prediction and handling different violent behaviors. In this work we go over the classic concept of "criminal dangerousness" and the more current of "violence risk assessment". We analyze the evolution of such assessment from the practice of non-structured clinical expert opinion to current actuarial methods and structured clinical expert opinion. Next we approach the problem of assessing physical violence risk analyzing the HCR-20 (Assessing Risk for Violence) and we also review the classic and complex subject of the relation between mental disease and violence. One of the most problematic types of violence, difficult to assess and predict, is sexual violence. We study the different actuarial and sexual violence risk prediction instruments and in the end we advise an integral approach to the problem. We also go through partner violence risk assessment, describing the most frequently used scales, especially SARA (Spouse Assault Risk Assessment) and EPV-R. Finally we give practical advice on risk assessment, emphasizing the importance of having maximum information about the case, carrying out a clinical examination, psychopathologic exploration and the application of one of the described risk assessment scales. We'll have to express an opinion about the dangerousness/risk of future violence from the subject and some recommendations on the conduct to follow and the most advisable treatment. Copyright © 2014 Elsevier España, S.L. All rights reserved.

  1. Condition-based Human Reliability Assessment for digitalized control room

    International Nuclear Information System (INIS)

    Kang, H. G.; Jang, S. C.; Eom, H. S.; Ha, J. J.

    2005-04-01

    In safety-critical systems, the generation failure of an actuation signal is caused by the concurrent failures of the automated systems and an operator action. These two sources of safety signals are complicatedly correlated. The failures of sensors or automated systems will cause a lack of necessary information for a human operator and result in error-forcing contexts such as the loss of corresponding alarms and indications. In the conventional analysis, the Human Error Probabilities (HEP) are estimated based on the assumption of 'normal condition of indications and alarms'. In order to construct a more realistic signal-generation failure model, we have to consider more complicated conditions in a more realistic manner. In this study, we performed two kinds of investigation for addressing this issue. We performed the analytic calculations for estimating the effect of sensors failures on the system unavailability and plant risk. For the single-parameter safety signals, the analysis result reveals that the quantification of the HEP should be performed by focusing on the 'no alarm from the automatic system and corresponding indications unavailable' situation. This study also proposes a Condition-Based Human Reliability Assessment (CBHRA) method in order to address these complicated conditions in a practical way. We apply the CBHRA method to the manual actuation of the safety features such as a reactor trip and auxiliary feedwater actuation in Korean Standard Nuclear Power Plants. In the case of conventional single HEP method, it is very hard to consider the multiple HE conditions. The merit of CBHRA is clearly shown in the application to the AFAS generation where no dominating HE condition exits. In this case, even if the HE conditions are carefully investigated, the single HEP method cannot accommodate the multiple conditions in a fault tree. On the other hand, the application result of the reactor trip in SLOCA shows that if there is a dominating condition, the use

  2. Risk assessment of complex accident scenarios

    International Nuclear Information System (INIS)

    Kluegel, Jens-Uwe

    2012-01-01

    The use of methods of risk assessment in accidents in nuclear plants is based on an old tradition. The first consistent systematic study is considered to be the Rasmussen Study of the U.S. Nuclear Regulatory Commission, NRC, WASH-1400. Above and beyond the realm of nuclear technology, there is an extensive range of accident, risk and reliability research into technical-administrative systems. In the past, it has been this area of research which has led to the development of concepts of safety precautions of the type also introduced into nuclear technology (barrier concept, defense in depth, single-failure criterion), where they are now taken for granted as trivial concepts. Also for risk analysis, nuclear technology made use of methods (such as event and fault tree analyses) whose origins were outside the nuclear field. One area in which the use of traditional methods of probabilistic safety analysis is encountering practical problems is risk assessment of complex accident scenarios in nuclear technology. A definition is offered of the term 'complex accident scenarios' in nuclear technology. A number of problems are addressed which arise in the use of traditional PSA procedures in risk assessment of complex accident scenarios. Cases of complex accident scenarios are presented to demonstrate methods of risk assessment which allow robust results to be obtained even when traditional techniques of risk analysis are maintained as a matter of principle. These methods are based on the use of conditional risk metrics. (orig.)

  3. Nanoscale deformation measurements for reliability assessment of material interfaces

    Science.gov (United States)

    Keller, Jürgen; Gollhardt, Astrid; Vogel, Dietmar; Michel, Bernd

    2006-03-01

    With the development and application of micro/nano electronic mechanical systems (MEMS, NEMS) for a variety of market segments new reliability issues will arise. The understanding of material interfaces is the key for a successful design for reliability of MEMS/NEMS and sensor systems. Furthermore in the field of BIOMEMS newly developed advanced materials and well known engineering materials are combined despite of fully developed reliability concepts for such devices and components. In addition the increasing interface-to volume ratio in highly integrated systems and nanoparticle filled materials are challenges for experimental reliability evaluation. New strategies for reliability assessment on the submicron scale are essential to fulfil the needs of future devices. In this paper a nanoscale resolution experimental method for the measurement of thermo-mechanical deformation at material interfaces is introduced. The determination of displacement fields is based on scanning probe microscopy (SPM) data. In-situ SPM scans of the analyzed object (i.e. material interface) are carried out at different thermo-mechanical load states. The obtained images are compared by grayscale cross correlation algorithms. This allows the tracking of local image patterns of the analyzed surface structure. The measurement results are full-field displacement fields with nanometer resolution. With the obtained data the mixed mode type of loading at material interfaces can be analyzed with highest resolution for future needs in micro system and nanotechnology.

  4. Risk assessment and regulation

    International Nuclear Information System (INIS)

    1981-01-01

    The approach to determining how safe is safe for the nuclear industry is to ensure that the risks are comparable with or less than those of other safe industries. There are some problems in implementing such an approach, because the effects of low levels of radiation are stochastic and assumptions are required in estimating the risks. A conservative approach has generally been adopted. Risk estimates across different activities are a useful indication of where society may be overspending or underspending to reduce risk, but the analysis has to take account of public preferences. Once risks have been estimated, limits may be chosen which the industry is expected to meet under normal and postulated accident conditions. Limits have been set so that nuclear risks do not exceed those in safe industries, and under normal conditions nuclear facilities operate at levels far below these specified limits

  5. Models for Pesticide Risk Assessment

    Science.gov (United States)

    EPA considers the toxicity of the pesticide as well as the amount of pesticide to which a person or the environments may be exposed in risk assessment. Scientists use mathematical models to predict pesticide concentrations in exposure assessment.

  6. Using risk assessment in periodontics.

    Science.gov (United States)

    Woodman, Alan J

    2014-08-01

    Risk assessment has become a regular feature in both dental practice and society as a whole, and principles used to assess risk in society are similar to those used in a clinical setting. Although the concept of risk assessment as a prognostic indicator for periodontal disease incidence and activity is well established in the management of periodontitis, the use of risk assessment to manage the practical treatment of periodontitis and its sequelae appears to have less foundation. A simple system of initial risk assessment - building on the use of the Basic Periodontal Examination (BPE), clinical, medical and social factors - is described, linked to protocols for delivering care suited to general dental practice and stressing the role of long-term supportive care. The risks of not treating the patient are considered, together with the possible causes of failure, and the problems of successful treatment are illustrated by the practical management of post-treatment recession.

  7. Mammography image assessment; validity and reliability of current scheme

    International Nuclear Information System (INIS)

    Hill, C.; Robinson, L.

    2015-01-01

    Mammographers currently score their own images according to criteria set out by Regional Quality Assurance. The criteria used are based on the ‘Perfect, Good, Moderate, Inadequate’ (PGMI) marking criteria established by the National Health Service Breast Screening Programme (NHSBSP) in their Quality Assurance Guidelines of 2006 1 . This document discusses the validity and reliability of the current mammography image assessment scheme. Commencing with a critical review of the literature this document sets out to highlight problems with the national approach to the use of marking schemes. The findings suggest that ‘PGMI’ scheme is flawed in terms of reliability and validity and is not universally applied across the UK. There also appear to be differences in schemes used by trainees and qualified mammographers. Initial recommendations are to be made in collaboration with colleagues within the National Health Service Breast Screening Programme (NHSBSP), Higher Education Centres, College of Radiographers and the Royal College of Radiologists in order to identify a mammography image appraisal scheme that is fit for purpose. - Highlights: • Currently no robust evidence based marking tools in use for the assessment of images in mammography. • Is current system valid, reliable and robust? • How can the current image assessment tool be improved? • Should students and qualified mammographers use the same tool? • What marking criteria are available for image assessment?

  8. Environmental Risk Communication through Qualitative Risk Assessment

    Directory of Open Access Journals (Sweden)

    Sabre J. Coleman

    2014-06-01

    Full Text Available Environmental analysts are often hampered in communicating the risks of environmental contaminants due to the myriad of regulatory requirements that are applicable. The use of a qualitative, risk-based control banding strategy for assessment and control of potential environmental contaminants provides a standardized approach to improve risk communication. Presented is a model that provides an effective means for determining standardized responses and controls for common environmental issues based on the level of risk. The model is designed for integration within an occupational health and safety management system to provide a multidisciplinary environmental and occupational risk management approach. This environmental model, which utilizes multidisciplinary control banding strategies for delineating risk, complements the existing Risk Level Based Management System, a proven method in a highly regulated facility for occupational health and safety. A simplified environmental risk matrix is presented that is stratified over four risk levels. Examples of qualitative environmental control banding strategies are presented as they apply to United States regulations for construction, research activities, facility maintenance, and spill remediation that affect air, water, soil, and waste disposal. This approach offers a standardized risk communication language for multidisciplinary issues that will improve communications within and between environmental health and safety professionals, workers, and management.

  9. The DYLAM approach to systems safety and reliability assessment

    International Nuclear Information System (INIS)

    Amendola, A.

    1988-01-01

    A survey of the principal features and applications of DYLAM (Dynamic Logical Analytical Methodology) is presented, whose basic principles can be summarized as follows: after a particular modelling of the component states, computerized heuristical procedures generate stochastic configurations of the system, whereas the resulting physical processes are simultaneously simulated to give account of the possible interactions between physics and states and, on the other hand, to search for system dangerous configurations and related probabilities. The association of probabilistic techniques for describing the states with physical equations for describing the process results in a very powerful tool for safety and reliability assessment of systems potentially subjected to dangerous incidental transients. A comprehensive picture of DYLAM capability for manifold applications can be obtained by the review of the study cases analyzed (LMFBR core accident, systems reliability assessment, accident simulation, man-machine interaction analysis, chemical reactors safety, etc.)

  10. Reliability-based condition assessment of steel containment and liners

    International Nuclear Information System (INIS)

    Ellingwood, B.; Bhattacharya, B.; Zheng, R.

    1996-11-01

    Steel containments and liners in nuclear power plants may be exposed to aggressive environments that may cause their strength and stiffness to decrease during the plant service life. Among the factors recognized as having the potential to cause structural deterioration are uniform, pitting or crevice corrosion; fatigue, including crack initiation and propagation to fracture; elevated temperature; and irradiation. The evaluation of steel containments and liners for continued service must provide assurance that they are able to withstand future extreme loads during the service period with a level of reliability that is sufficient for public safety. Rational methodologies to provide such assurances can be developed using modern structural reliability analysis principles that take uncertainties in loading, strength, and degradation resulting from environmental factors into account. The research described in this report is in support of the Steel Containments and Liners Program being conducted for the US Nuclear Regulatory Commission by the Oak Ridge National Laboratory. The research demonstrates the feasibility of using reliability analysis as a tool for performing condition assessments and service life predictions of steel containments and liners. Mathematical models that describe time-dependent changes in steel due to aggressive environmental factors are identified, and statistical data supporting the use of these models in time-dependent reliability analysis are summarized. The analysis of steel containment fragility is described, and simple illustrations of the impact on reliability of structural degradation are provided. The role of nondestructive evaluation in time-dependent reliability analysis, both in terms of defect detection and sizing, is examined. A Markov model provides a tool for accounting for time-dependent changes in damage condition of a structural component or system. 151 refs

  11. Statistical reliability assessment of software-based systems

    International Nuclear Information System (INIS)

    Korhonen, J.; Pulkkinen, U.; Haapanen, P.

    1997-01-01

    Plant vendors nowadays propose software-based systems even for the most critical safety functions. The reliability estimation of safety critical software-based systems is difficult since the conventional modeling techniques do not necessarily apply to the analysis of these systems, and the quantification seems to be impossible. Due to lack of operational experience and due to the nature of software faults, the conventional reliability estimation methods can not be applied. New methods are therefore needed for the safety assessment of software-based systems. In the research project Programmable automation systems in nuclear power plants (OHA), financed together by the Finnish Centre for Radiation and Nuclear Safety (STUK), the Ministry of Trade and Industry and the Technical Research Centre of Finland (VTT), various safety assessment methods and tools for software based systems are developed and evaluated. This volume in the OHA-report series deals with the statistical reliability assessment of software based systems on the basis of dynamic test results and qualitative evidence from the system design process. Other reports to be published later on in OHA-report series will handle the diversity requirements in safety critical software-based systems, generation of test data from operational profiles and handling of programmable automation in plant PSA-studies. (orig.) (25 refs.)

  12. 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.

  13. RESIDUAL RISK ASSESSMENT: ETHYLENE OXIDE ...

    Science.gov (United States)

    This document describes the residual risk assessment for the Ethylene Oxide Commercial Sterilization source category. For stationary sources, section 112 (f) of the Clean Air Act requires EPA to assess risks to human health and the environment following implementation of technology-based control standards. If these technology-based control standards do not provide an ample margin of safety, then EPA is required to promulgate addtional standards. This document describes the methodology and results of the residual risk assessment performed for the Ethylene Oxide Commercial Sterilization source category. The results of this analyiss will assist EPA in determining whether a residual risk rule for this source category is appropriate.

  14. Assessing personality risks using the Surps for alcohol and other ...

    African Journals Online (AJOL)

    Assessing personality risks using the Surps for alcohol and other drug problems in Cape Town, South Africa. ... African Journal of Drug and Alcohol Studies ... In this crosssectional study, the Substance Use Risk Profile Scale (SURPS) was applied to measure these traits and assess the questionnaire's reliability from a ...

  15. Reliability assessment of the containment of a PWR

    International Nuclear Information System (INIS)

    Schueller, G.I.; Wellein, R.; Wittmann, F.H.; Boulahdour, T.; Mihashi, M.; Zorn, N.F.; Bauer, J.

    1981-09-01

    The aim of this research effort was to contribute to the development of methods to quantify the risk involved with nuclear power plants. Using a large component, i.e. the containment of the reference plant BIBLIS B (PWR) as sample structure a reliability analysis was performed which is based on realistic assumptions of loads and material properties. For this purpose in many fields it was necessary to develop new methods, collect data, and where not available, obtain data in tests. This effort concentrated on partial aspects and on the other hand on the development of a methodology for an overall reliability concept. According to the results of the previous project, the keypoints of this effort are the treatment of loss of coolant accidents (small leak), earthquake loading, the possibly resulting crackpropagation in the steel hull, and the structural mechanics and material strength aspects of the reinforced concrete hull subjected to impact loading (aircraft impact). (orig./HP) [de

  16. Systems reliability analyses and risk analyses for the licencing procedure under atomic law

    International Nuclear Information System (INIS)

    Berning, A.; Spindler, H.

    1983-01-01

    For the licencing procedure under atomic law in accordance with Article 7 AtG, the nuclear power plant as a whole needs to be assessed, plus the reliability of systems and plant components that are essential to safety are to be determined with probabilistic methods. This requirement is the consequence of safety criteria for nuclear power plants issued by the Home Department (BMI). Systems reliability studies and risk analyses used in licencing procedures under atomic law are identified. The stress is on licencing decisions, mainly for PWR-type reactors. Reactor Safety Commission (RSK) guidelines, examples of reasoning in legal proceedings and arguments put forth by objectors are also dealt with. Correlations are shown between reliability analyses made by experts and licencing decisions by means of examples. (orig./HP) [de

  17. Reliability assessment of passive containment isolation system using APSRA methodology

    International Nuclear Information System (INIS)

    Nayak, A.K.; Jain, Vikas; Gartia, M.R.; Srivastava, A.; Prasad, Hari; Anthony, A.; Gaikwad, A.J.; Bhatia, S.; Sinha, R.K.

    2008-01-01

    In this paper, a methodology known as APSRA (Assessment of Passive System ReliAbility) has been employed for evaluation of the reliability of passive systems. The methodology has been applied to the passive containment isolation system (PCIS) of the Indian advanced heavy water reactor (AHWR). In the APSRA methodology, the passive system reliability evaluation is based on the failure probability of the system to carryout the desired function. The methodology first determines the operational characteristics of the system and the failure conditions by assigning a predetermined failure criterion. The failure surface is predicted using a best estimate code considering deviations of the operating parameters from their nominal states, which affect the PCIS performance. APSRA proposes to compare the code predictions with the test data to generate the uncertainties on the failure parameter prediction, which is later considered in the code for accurate prediction of failure surface of the system. Once the failure surface of the system is predicted, the cause of failure is examined through root diagnosis, which occurs mainly due to failure of mechanical components. The failure probability of these components is evaluated through a classical PSA treatment using the generic data. The reliability of the PCIS is evaluated from the probability of availability of the components for the success of the passive containment isolation system

  18. Risk indices in comparative risk assessment studies

    International Nuclear Information System (INIS)

    Hubert, P.

    1984-01-01

    More than a decade ago the development of comparative risk assessment studies aroused overwhelming interest. There was no doubt that data on the health and safety aspects of energy systems would greatly benefit, or even end, the debate on nuclear energy. Although such attempts are still strongly supported, the rose-coloured expectations of the early days have faded. The high uncertainties, and the contradictory aspect, of the first results might explain this evolution. The loose connection between the range of computed risk indices and the questions on which the debate was focused is another reason for this decline in interest. Important research work is being carried out aiming at reducing the different kinds of uncertainties. Rather than the uncertainties, the paper considers the meaning of available risk indices and proposes more significant indices with respect to the goals of risk assessment. First, the indices which are of frequent use in comparative studies are listed. The stress is put on a French comparative study from which most examples are drawn. Secondly, the increase in magnitude of the indices and the decrease in the attributability of the risk to a given system is shown to be a consequence of the trend towards more comprehensive analyses. Thirdly, the ambiguity of such indices as the collective occupational risk is underlined, and a possible solution is suggested. Whenever risk assessments are related to pragmatic decision making problems it is possible to find satisfactory risk indices. The development of cost-effectiveness analyses and the proposals for quantitative safety goals clearly demonstrate this point. In the field of comparison of social impacts some proposals are made, but there remain some gaps still to be filled. (author)

  19. A reliability-risk modelling of nuclear rad-waste facilities

    International Nuclear Information System (INIS)

    Lehmann, P.H.; El-Bassioni, A.A.

    1975-01-01

    Rad-waste disposal systems of nuclear power sites are designed and operated to collect, delay, contain, and concentrate radioactive wastes from reactor plant processes such that on-site and off-site exposures to radiation are well below permissible limits. To assist the designer in achieving minimum release/exposure goals, a computerized reliability-risk model has been developed to simulate the rad-waste system. The objectives of the model are to furnish a practical tool for quantifying the effects of changes in system configuration, operation, and equipment, and for the identification of weak segments in the system design. Primarily, the model comprises a marriage of system analysis, reliability analysis, and release-risk assessment. Provisions have been included in the model to permit the optimization of the system design subject to constraints on cost and rad-releases. The system analysis phase involves the preparation of a physical and functional description of the rad-waste facility accompanied by the formation of a system tree diagram. The reliability analysis phase embodies the formulation of appropriate reliability models and the collection of model parameters. Release-risk assessment constitutes the analytical basis whereupon further system and reliability analyses may be warranted. Release-risk represents the potential for release of radioactivity and is defined as the product of an element's unreliability at time, t, and the radioactivity available for release in time interval, Δt. A computer code (RARISK) has been written to simulate the tree diagram of the rad-waste system. Reliability and release-risk results have been generated for cases which examined the process flow paths of typical rad-waste systems, the effects of repair and standby, the variations of equipment failure and repair rates, and changes in system configurations. The essential feature of this model is that a complex system like the rad-waste facility can be easily decomposed into its

  20. Design and reliability of a didactic inphographic rubric assessment

    Directory of Open Access Journals (Sweden)

    Yunuen Ixchel GUZMÁN-CEDILLO

    2017-12-01

    Full Text Available The objective of this study is to describe design, validity process and reliability of a rubric assessment to evaluate didactic infographics quality. Participants were fifteen judges who participate in different moments of elaboration rubric process; it was made in three process phases: design, settings and reliability determination. Content validity was obtained by percentage agreement between 3 judges by component of the rubric; likewise a Krippendorff’s alpha were applied (a = .710 in pilot assessment with 5 infographics in order to set possible writings contradictions between components and criteria of performance. The intern consistence was determined by Cronbach’s alpha (? = .806 in 22 infographics gradation. An Intraclass correlation coefficient icc (a = .909 was applied to 6 judges qualifications also a Krippendorff’s alpha (a = .538 both of them in ordinal levels. The rubric is composed by 9 components, 3 performance levels, definitions of each component and assignments how to use the rubric. Results suggest the rubric is valid and reliable to grade quality of didactic infographic.

  1. Evolutionary leap in large-scale flood risk assessment needed

    OpenAIRE

    Vorogushyn, Sergiy; Bates, Paul D.; de Bruijn, Karin; Castellarin, Attilio; Kreibich, Heidi; Priest, Sally J.; Schröter, Kai; Bagli, Stefano; Blöschl, Günter; Domeneghetti, Alessio; Gouldby, Ben; Klijn, Frans; Lammersen, Rita; Neal, Jeffrey C.; Ridder, Nina

    2018-01-01

    Current approaches for assessing large-scale flood risks contravene the fundamental principles of the flood risk system functioning because they largely ignore basic interactions and feedbacks between atmosphere, catchments, river-floodplain systems and socio-economic processes. As a consequence, risk analyses are uncertain and might be biased. However, reliable risk estimates are required for prioritizing national investments in flood risk mitigation or for appraisal and management of insura...

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

    Science.gov (United States)

    Ghaffarian, Reza; Evans, John W.

    2014-01-01

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

  3. Reliability and Validity Assessment of a Linear Position Transducer

    Directory of Open Access Journals (Sweden)

    Manuel V. Garnacho-Castaño

    2015-03-01

    Full Text Available The objectives of the study were to determine the validity and reliability of peak velocity (PV, average velocity (AV, peak power (PP and average power (AP measurements were made using a linear position transducer. Validity was assessed by comparing measurements simultaneously obtained using the Tendo Weightlifting Analyzer Systemi and T-Force Dynamic Measurement Systemr (Ergotech, Murcia, Spain during two resistance exercises, bench press (BP and full back squat (BS, performed by 71 trained male subjects. For the reliability study, a further 32 men completed both lifts using the Tendo Weightlifting Analyzer Systemz in two identical testing sessions one week apart (session 1 vs. session 2. Intraclass correlation coefficients (ICCs indicating the validity of the Tendo Weightlifting Analyzer Systemi were high, with values ranging from 0.853 to 0.989. Systematic biases and random errors were low to moderate for almost all variables, being higher in the case of PP (bias ±157.56 W; error ±131.84 W. Proportional biases were identified for almost all variables. Test-retest reliability was strong with ICCs ranging from 0.922 to 0.988. Reliability results also showed minimal systematic biases and random errors, which were only significant for PP (bias -19.19 W; error ±67.57 W. Only PV recorded in the BS showed no significant proportional bias. The Tendo Weightlifting Analyzer Systemi emerged as a reliable system for measuring movement velocity and estimating power in resistance exercises. The low biases and random errors observed here (mainly AV, AP make this device a useful tool for monitoring resistance training.

  4. Implications of probabilistic risk assessment

    International Nuclear Information System (INIS)

    Cullingford, M.C.; Shah, S.M.; Gittus, J.H.

    1987-01-01

    Probabilistic risk assessment (PRA) is an analytical process that quantifies the likelihoods, consequences and associated uncertainties of the potential outcomes of postulated events. Starting with planned or normal operation, probabilistic risk assessment covers a wide range of potential accidents and considers the whole plant and the interactions of systems and human actions. Probabilistic risk assessment can be applied in safety decisions in design, licensing and operation of industrial facilities, particularly nuclear power plants. The proceedings include a review of PRA procedures, methods and technical issues in treating uncertainties, operating and licensing issues and future trends. Risk assessment for specific reactor types or components and specific risks (eg aircraft crashing onto a reactor) are used to illustrate the points raised. All 52 articles are indexed separately. (U.K.)

  5. Reliability Assessment of Transformerless PV Inverters Considering Mission Profiles

    DEFF Research Database (Denmark)

    Yang, Yongheng; Wang, Huai; Blaabjerg, Frede

    2015-01-01

    reliability of three transformerless inverters under a yearly mission profile (i.e., solar irradiance and ambient temperature). The mission profile is translated to device thermal loading, which is used for lifetime prediction. Compar¬ison results reveal the lifetime mismatches among the power switching......Due to the small volume and high efficiency, transformerless inverters have gained much popularity in grid-connected PV applications, where minimizing leakage current injection is mandatory. This can be achieved either by modifying the modulation schemes or adding extra power switching devices......, resulting in an uneven distribution of the power losses on the switching devices. Consequently, the device thermal loading is redis-tributed, and thus may alter the entire inverter reliability performance, especially under a long-term operation. In this consideration, this paper assesses the device...

  6. Tools for Microbiological risk assessment

    DEFF Research Database (Denmark)

    Bassett, john; Nauta, Maarten; Lindqvist, Roland

    can increase the understanding of microbiological risks in foods. It is timely to inform food safety professionals about the availability and utility of MRA tools. Therefore, the focus of this report is to aid the food safety manager by providing a concise summary of the tools available for the MRA......Microbiological Risk Assessment (MRA) has emerged as a comprehensive and systematic approach for addressing the risk of pathogens in specific foods and/or processes. At government level, MRA is increasingly recognised as a structured and objective approach to understand the level of risk in a given...... food/pathogen scenario. Tools developed so far support qualitative and quantitative assessments of the risk that a food pathogen poses to a particular population. Risk can be expressed as absolute numbers or as relative (ranked) risks. The food industry is beginning to appreciate that the tools for MRA...

  7. Reliability assessment of creep rupture life for Gr. 91 steel

    International Nuclear Information System (INIS)

    Kim, Woo-Gon; Park, Jae-Young; Kim, Seon-Jin; Jang, Jinsung

    2013-01-01

    Highlights: • Statistical analysis of a number of creep rupture data based on Z parameter. • Determination of the constant C in LM parameter and long-term creep life prediction. • Generation of random variables for Z s and Z cr by Monte-Carlo simulation in a SCRI model. • Examples for design application were reasonably drawn from the viewpoints of reliability. - Abstract: This paper presents reliability assessment of the long-term creep life of Gr. 91 steel, which is a major structural material for high temperature structural components of Generation-IV reactor systems. A number of creep rupture data for Gr. 91 steel were collected through literature surveys, and the long-term creep life was predicted by Larson–Miller parameter. A “Z parameter” method was used to describe the magnitude of the deviation of the creep rupture data to a master curve. A “Service Condition-creep Rupture property Interference (SCRI) model” based on the Z parameter was used to simultaneously consider the scattering of the creep rupture data of materials and the fluctuations of service conditions in reliability assessment. A statistical analysis of the creep rupture data was conducted by the Z parameter. To carry out the SCRI model, a number of random variables for Z s describing service conditions and Z cr describing the dispersion of the creep rupture data were generated using a Monte-Carlo simulation technique. As examples for application, the creep rupture life under a certain service conditions of Gr. 91 steel was reasonably drawn from the viewpoints of reliability

  8. Configuration of risk monitor system by plant defense-in-depth risk monitor and reliability monitor

    International Nuclear Information System (INIS)

    Yoshikawa, Hidekazu; Lind Morten; Yang Ming; Hashim Muhammad; Zhang Zhijian

    2012-01-01

    A new method of risk monitor system of a nuclear power plant has been proposed from the aspect by what degree of safety functions incorporated in the plant system is maintained by multiple barriers of defense-in-depth (DiD). Wherein, the central idea is plant DiD risk monitor and reliability monitor derived from the five aspects of (1) design principle of nuclear safety based on DiD concept, (2) definition of risk and risk to be monitored, (3) severe accident phenomena as major risk, (4) scheme of risk ranking, and (5) dynamic risk display. In this paper, the overall frame of the proposed risk monitor system is summarized and the detailed discussion is made on major items such as definition of risk and risk ranking, anatomy of fault occurrence, two-layer configuration of risk monitor, how to configure individual elements of plant DiD risk monitor, and lastly how to apply for a PWR safety system. (author)

  9. Integrated climate change risk assessment:

    DEFF Research Database (Denmark)

    Kaspersen, Per Skougaard; Halsnæs, Kirsten

    2017-01-01

    Risk assessments of flooding in urban areas during extreme precipitation for use in, for example, decision-making regarding climate adaptation, are surrounded by great uncertainties stemming from climate model projections, methods of downscaling and the assumptions of socioeconomic impact models...... to address the complex linkages between the different kinds of data required in assessing climate adaptation. It emphasizes that the availability of spatially explicit data can reduce the overall uncertainty of the risk assessment and assist in identifying key vulnerable assets. The usefulness...... of such a framework is demonstrated by means of a risk assessment of flooding from extreme precipitation for the city of Odense, Denmark. A sensitivity analysis shows how the presence of particularly important assets, such as cultural and historical heritage, may be addressed in assessing such risks. The output...

  10. New approaches for improving cardiovascular risk assessment.

    Science.gov (United States)

    Paredes, Simão; Rocha, Teresa; Mendes, Diana; Carvalho, Paulo; Henriques, Jorge; Morais, João; Ferreira, Jorge; Mendes, Miguel

    2016-01-01

    Clinical guidelines recommend the use of cardiovascular risk assessment tools (risk scores) to predict the risk of events such as cardiovascular death, since these scores can aid clinical decision-making and thereby reduce the social and economic costs of cardiovascular disease (CVD). However, despite their importance, risk scores present important weaknesses that can diminish their reliability in clinical contexts. This study presents a new framework, based on current risk assessment tools, that aims to minimize these limitations. Appropriate application and combination of existing knowledge is the main focus of this work. Two different methodologies are applied: (i) a combination scheme that enables data to be extracted and processed from various sources of information, including current risk assessment tools and the contributions of the physician; and (ii) a personalization scheme based on the creation of patient groups with the purpose of identifying the most suitable risk assessment tool to assess the risk of a specific patient. Validation was performed based on a real patient dataset of 460 patients at Santa Cruz Hospital, Lisbon, Portugal, diagnosed with non-ST-segment elevation acute coronary syndrome. Promising results were obtained with both approaches, which achieved sensitivity, specificity and geometric mean of 78.79%, 73.07% and 75.87%, and 75.69%, 69.79% and 72.71%, respectively. The proposed approaches present better performances than current CVD risk scores; however, additional datasets are required to back up these findings. Copyright © 2015 Sociedade Portuguesa de Cardiologia. Published by Elsevier España. All rights reserved.

  11. 'Living PRA' concept for plant risk: Reliability and availability tracking

    International Nuclear Information System (INIS)

    Sancaktar, S.; Sharp, D.R.

    1985-01-01

    The 'Living PRA' (Probabilistic Risk Assessment) is based on placing a PRA plant model on an interactive computer. This model consists of fault tree analyses for plant systems, event tree analyses for abnormal events and site specific consequence analysis for public and/or financial risks, for a nuclear power plant. A living PRA allows updates and sensitivity analyses by the plant owner throughout the lifetime of a plant. Recently, event and fault trees from two major PRAs were placed in a computerized format. The BYRON PRA study and the Living PRA and Economic Risk examples for Indian Point Unit-3 enabled analysts to gain experience and insight into the problems of plant operation. The above concept is well established for the Nuclear Power Plant evaluation. It has been also used for evaluation of processing facilities. In these studies, systems modeling was carried out by using the GRAFTER system for automated fault tree construction. Presently both the tools and the experience exists to set up useful and viable living PRA models for nuclear and chemical processing plants to enhance risk management by the plant owners through in-house use of micro computer based models

  12. Reliability assessment of aging structures subjected to gradual and shock deteriorations

    International Nuclear Information System (INIS)

    Wang, Cao; Zhang, Hao; Li, Quanwang

    2017-01-01

    Civil structures and infrastructure facilities are susceptible to deterioration posed by the effects of natural hazards and aggressive environmental conditions. These factors may increase the risk of service interruption of infrastructures, and should be taken into account when assessing the structural reliability during an infrastructure's service life. Modeling the resistance deterioration process reasonably is the basis for structural reliability analysis. In this paper, a novel model is developed for describing the deterioration of aging structures. The deterioration is a combination of two stochastic processes: the gradual deterioration posed by environmental effects and the shock deterioration caused by severe load attacks. The dependency of the deterioration magnitude on the load intensity is considered. The Gaussian copula function is employed to help construct the joint distribution of correlated random variables. Semi-analytical methods are developed to assess the structural failure time and the number of significant load events (shocks) to failure. Illustrative examples are presented to demonstrate the applicability of the proposed model in structural reliability analysis. Parametric studies are performed to investigate the role of deterioration-load correlation in structural reliability. - Highlights: • A new resistance deterioration model for aging structures is proposed. • Time-dependent reliability analysis methods incorporating the proposed deterioration model are developed. • Parametric studies are performed to investigate the role of deterioration-load correlation in structural reliability.

  13. Carcinogen risk assessment

    International Nuclear Information System (INIS)

    Hazelwoold, R.N.

    1987-01-01

    This article describes the methods by which risk factors for carcinogenic hazards are determined and the limitations inherent in the process. From statistical and epidemiological studies, the major identifiable factors related to cancer in the United States were determined to be cigarette smoking, diet, reproductive and sexual behavior, infections, ultraviolet and ionizing radiation, and alcohol consumption. The incidence of lung cancer due to air pollutants was estimated to be less than 2%. Research needs were discussed

  14. Probabilistic risk assessment, Volume I

    International Nuclear Information System (INIS)

    Anon.

    1982-01-01

    This book contains 158 papers presented at the International Topical Meeting on Probabilistic Risk Assessment held by the American Nuclear Society (ANS) and the European Nuclear Society (ENS) in Port Chester, New York in 1981. The meeting was second in a series of three. The main focus of the meeting was on the safety of light water reactors. The papers discuss safety goals and risk assessment. Quantitative safety goals, risk assessment in non-nuclear technologies, and operational experience and data base are also covered. Included is an address by Dr. Chauncey Starr

  15. Risk assessment in maritime transportation

    International Nuclear Information System (INIS)

    Soares, C. Guedes; Teixeira, A.P.

    2001-01-01

    A review is presented of different approaches to quantify the risk in maritime transportation. The discussion of several accident statistics provides a global assessment of the risk levels and its differentiation in ship types and main types of ship losses. Early studies in the probability of ship loss by foundering and capsizing are reviewed. The approaches used to assess the risk of structural design are addressed. Finally a brief account is given of recent development of using formal safety assessments to support decision making on legislation applicable internationally to maritime transportation

  16. Framework for ecological risk assessment

    International Nuclear Information System (INIS)

    Rodier, D.; Norton, S.

    1992-02-01

    Increased interest in ecological issues such as global climate change, habitat loss, acid deposition, reduced biological diversity, and the ecological impacts of pesticides and toxic chemicals prompts this U.S. Environmental Protection Agency (EPA) report, A Framework for Ecological Risk Assessment ('Framework Report'). The report describes basic elements, or a framework, for evaluating scientific information on the adverse effects of physical and chemical stressors on the environment. The framework offers starting principles and a simple structure as guidance for current ecological risk assessments and as a foundation for future EPA proposals for risk assessment guidelines

  17. Risk Assessment and Integration Team (RAIT) Portfolio Risk Analysis Strategy

    Science.gov (United States)

    Edwards, Michelle

    2010-01-01

    Impact at management level: Qualitative assessment of risk criticality in conjunction with risk consequence, likelihood, and severity enable development of an "investment policy" towards managing a portfolio of risks. Impact at research level: Quantitative risk assessments enable researchers to develop risk mitigation strategies with meaningful risk reduction results. Quantitative assessment approach provides useful risk mitigation information.

  18. Quantitative risk assessment system (QRAS)

    Science.gov (United States)

    Weinstock, Robert M (Inventor); Smidts, Carol S (Inventor); Mosleh, Ali (Inventor); Chang, Yung-Hsien (Inventor); Swaminathan, Sankaran (Inventor); Groen, Francisco J (Inventor); Tan, Zhibin (Inventor)

    2001-01-01

    A quantitative risk assessment system (QRAS) builds a risk model of a system for which risk of failure is being assessed, then analyzes the risk of the system corresponding to the risk model. The QRAS performs sensitivity analysis of the risk model by altering fundamental components and quantifications built into the risk model, then re-analyzes the risk of the system using the modifications. More particularly, the risk model is built by building a hierarchy, creating a mission timeline, quantifying failure modes, and building/editing event sequence diagrams. Multiplicities, dependencies, and redundancies of the system are included in the risk model. For analysis runs, a fixed baseline is first constructed and stored. This baseline contains the lowest level scenarios, preserved in event tree structure. The analysis runs, at any level of the hierarchy and below, access this baseline for risk quantitative computation as well as ranking of particular risks. A standalone Tool Box capability exists, allowing the user to store application programs within QRAS.

  19. Reliability, compliance, and security in web-based course assessments

    Directory of Open Access Journals (Sweden)

    Scott Bonham

    2008-04-01

    Full Text Available Pre- and postcourse assessment has become a very important tool for education research in physics and other areas. The web offers an attractive alternative to in-class paper administration, but concerns about web-based administration include reliability due to changes in medium, student compliance rates, and test security, both question leakage and utilization of web resources. An investigation was carried out in introductory astronomy courses comparing pre- and postcourse administration of assessments using the web and on paper. Overall no difference was seen in performance due to the medium. Compliance rates fluctuated greatly, and factors that seemed to produce higher rates are identified. Notably, email reminders increased compliance by 20%. Most of the 559 students complied with requests to not copy, print, or save questions nor use web resources; about 1% did copy some question text and around 2% frequently used other windows or applications while completing the assessment.

  20. Risk assessment: An employer's perspective

    International Nuclear Information System (INIS)

    Williams, K.C.

    1992-01-01

    There is no question that a careful assessment of risk is essential for safe industrial operations. For that reason, a thoughtful analysis of the effectiveness of available risk assessment technologies is prerequisite for responsible corporate decision making. An 'employer's' perspective on risk assessment cannot be constrained by any artificial restrictions which that term may imply. In reality, all those who are involved in the execution of an industrial enterprise: managers, regulators, the affected public, and especially those employees exposed to hazards, are necessarily partners in assessment of risk. The perspective of this paper is that of the oil and gas industry, in which the author's organization, Exxon Company, International, participates. The paper addresses what Exxon requires to assess and manage risk in its worldwide operations. The author is aware, however, through contacts with industry colleagues, that some of Exxon's initiatives are representative of similar actions being taken by others. 1992 is the European Year of Safety, Health and Hygiene, coinciding with the United Kingdom's Presidency of the European Council. It is also the year in which new 'goal-setting' regulations covering safety in the U.K. offshore oil industry were put forward by the Health and Safety Commission. These regulations, based largely on Lord Cullen's recommendations following the Piper Alpha tragedy, set the pace for safety in the British North Sea and will significantly impact the safety of offshore oil installations worldwide. The requirement for risk assessment, using a systematic process of analysing and evaluating risk, is a key component of this safety regime

  1. Risk assessment: An employer's perspective

    Energy Technology Data Exchange (ETDEWEB)

    Williams, K C [Exxon International (United States)

    1992-07-01

    There is no question that a careful assessment of risk is essential for safe industrial operations. For that reason, a thoughtful analysis of the effectiveness of available risk assessment technologies is prerequisite for responsible corporate decision making. An 'employer's' perspective on risk assessment cannot be constrained by any artificial restrictions which that term may imply. In reality, all those who are involved in the execution of an industrial enterprise: managers, regulators, the affected public, and especially those employees exposed to hazards, are necessarily partners in assessment of risk. The perspective of this paper is that of the oil and gas industry, in which the author's organization, Exxon Company, International, participates. The paper addresses what Exxon requires to assess and manage risk in its worldwide operations. The author is aware, however, through contacts with industry colleagues, that some of Exxon's initiatives are representative of similar actions being taken by others. 1992 is the European Year of Safety, Health and Hygiene, coinciding with the United Kingdom's Presidency of the European Council. It is also the year in which new 'goal-setting' regulations covering safety in the U.K. offshore oil industry were put forward by the Health and Safety Commission. These regulations, based largely on Lord Cullen's recommendations following the Piper Alpha tragedy, set the pace for safety in the British North Sea and will significantly impact the safety of offshore oil installations worldwide. The requirement for risk assessment, using a systematic process of analysing and evaluating risk, is a key component of this safety regime.

  2. Risk assessment in international operations

    International Nuclear Information System (INIS)

    Stricklin, Daniela L.

    2008-01-01

    During international peace-keeping missions, a diverse number of non-battle hazards may be encountered, which range from heavily polluted areas, endemic disease, toxic industrial materials, local violence, traffic, and even psychological factors. Hence, elevated risk levels from a variety of sources are encountered during deployments. With the emphasis within the Swedish military moving from national defense towards prioritization of international missions in atypical environments, the risk of health consequences, including long term health effects, has received greater consideration. The Swedish military is interested in designing an optimal approach for assessment of health threats during deployments. The Medical Intelligence group at FOI CBRN Security and Defence in Umea has, on request from and in collaboration with the Swedish Armed Forces, reviewed a variety of international health threat and risk assessment models for military operations. Application of risk assessment methods used in different phases of military operations will be reviewed. An overview of different international approaches used in operational risk management (ORM) will be presented as well as a discussion of the specific needs and constraints for health risk assessment in military operations. This work highlights the specific challenges of risk assessment that are unique to the deployment setting such as the assessment of exposures to a variety of diverse hazards concurrently

  3. Assessment and perception of risk

    Energy Technology Data Exchange (ETDEWEB)

    Daglish, J

    1981-01-01

    A recent two-day meeting was called by the Royal Society to discuss all types of risks, but symptomatic of the concerns of most of those present, the discussion centred mainly on the risks inherent in energy production and use. Among the subjects considered were public perception of differing risks, and how these are ranked, and risks versus benefits. Quotations from and summaries of many of the papers presented show that it was generally felt that scientists must be very careful in the way that they use numerical assessments of risk and that they should pay more attention than they have to social and political factors.

  4. Risk assessment in man and mouse.

    Science.gov (United States)

    Balci, Fuat; Freestone, David; Gallistel, Charles R

    2009-02-17

    Human and mouse subjects tried to anticipate at which of 2 locations a reward would appear. On a randomly scheduled fraction of the trials, it appeared with a short latency at one location; on the complementary fraction, it appeared after a longer latency at the other location. Subjects of both species accurately assessed the exogenous uncertainty (the probability of a short versus a long trial) and the endogenous uncertainty (from the scalar variability in their estimates of an elapsed duration) to compute the optimal target latency for a switch from the short- to the long-latency location. The optimal latency was arrived at so rapidly that there was no reliably discernible improvement over trials. Under these nonverbal conditions, humans and mice accurately assess risks and behave nearly optimally. That this capacity is well-developed in the mouse opens up the possibility of a genetic approach to the neurobiological mechanisms underlying risk assessment.

  5. A Mechanistic Reliability Assessment of RVACS and Metal Fuel Inherent Reactivity Feedbacks

    Energy Technology Data Exchange (ETDEWEB)

    Grabaskas, David; Brunett, Acacia J.; Passerini, Stefano; Grelle, Austin

    2017-09-24

    GE Hitachi Nuclear Energy (GEH) and Argonne National Laboratory (Argonne) participated in a two year collaboration to modernize and update the probabilistic risk assessment (PRA) for the PRISM sodium fast reactor. At a high level, the primary outcome of the project was the development of a next-generation PRA that is intended to enable risk-informed prioritization of safety- and reliability-focused research and development. A central Argonne task during this project was a reliability assessment of passive safety systems, which included the Reactor Vessel Auxiliary Cooling System (RVACS) and the inherent reactivity feedbacks of the metal fuel core. Both systems were examined utilizing a methodology derived from the Reliability Method for Passive Safety Functions (RMPS), with an emphasis on developing success criteria based on mechanistic system modeling while also maintaining consistency with the Fuel Damage Categories (FDCs) of the mechanistic source term assessment. This paper provides an overview of the reliability analyses of both systems, including highlights of the FMEAs, the construction of best-estimate models, uncertain parameter screening and propagation, and the quantification of system failure probability. In particular, special focus is given to the methodologies to perform the analysis of uncertainty propagation and the determination of the likelihood of violating FDC limits. Additionally, important lessons learned are also reviewed, such as optimal sampling methodologies for the discovery of low likelihood failure events and strategies for the combined treatment of aleatory and epistemic uncertainties.

  6. Reliability of Volumetry and Perimetry to Assess Knee Volume.

    Science.gov (United States)

    Nunes, Guilherme S; Yamashitafuji, Igor; Wageck, Bruna; Teixeira, Guilherme Garcia; Karloh, Manuela; de Noronha, Marcos

    2016-08-24

    The treatment of edema after a knee injury is usually 1 of the main objectives during rehabilitation. To assess the success of treatment, 2 methods are commonly used in clinical practice: volumetry and perimetry. To investigate the intra- and interassessor reliability of volumetry and perimetry to assess knee volume. Cross-sectional. Laboratory. 45 healthy participants (26 women) with mean age of 22.4 ± 2.8 y. Knee volume was assessed by 3 assessors (A, B, and C) with 3 methods (lower-limb volumetry [LLV], knee volumetry [KV], and knee perimetry [KP]). Assessor A was the most-experienced assessor, and assessor C, the least experienced. LLV and KV were performed with participants in the orthostatic position, while KP was performed with participants in supine. For the interassessor analysis, the ICC2,1 was high (.82) for KV and very high for LLV (.99) and KP (.99). For the intra-assessor analysis, ICC2,1 ranged from moderate to high for KV (.69-.83) and was very high for LLV (.99) and KP (.97-.99). KV, LLV, and KP are reliable methods, both intra- and interassessor, to measure knee volume.

  7. Assessing Reliability of Cold Spray Sputter Targets in Photovoltaic Manufacturing

    Science.gov (United States)

    Hardikar, Kedar; Vlcek, Johannes; Bheemreddy, Venkata; Juliano, Daniel

    2017-10-01

    Cold spray has been used to manufacture more than 800 Cu-In-Ga (CIG) sputter targets for deposition of high-efficiency photovoltaic thin films. It is a preferred technique since it enables high deposit purity and transfer of non-equilibrium alloy states to the target material. In this work, an integrated approach to reliability assessment of such targets with deposit weight in excess of 50 lb. is undertaken, involving thermal-mechanical characterization of the material in as-deposited condition, characterization of the interface adhesion on cylindrical substrate in as-deposited condition, and developing means to assess target integrity under thermal-mechanical loads during the physical vapor deposition (PVD) sputtering process. Mechanical characterization of cold spray deposited CIG alloy is accomplished through the use of indentation testing and adaptation of Brazilian disk test. A custom lever test was developed to characterize adhesion along the cylindrical interface between the CIG deposit and cylindrical substrate, overcoming limitations of current standards. A cohesive zone model for crack initiation and propagation at the deposit interface is developed and validated using the lever test and later used to simulate the potential catastrophic target failure in the PVD process. It is shown that this approach enables reliability assessment of sputter targets and improves robustness.

  8. Method for assessing reliability of a network considering probabilistic safety assessment

    International Nuclear Information System (INIS)

    Cepin, M.

    2005-01-01

    A method for assessment of reliability of the network is developed, which uses the features of the fault tree analysis. The method is developed in a way that the increase of the network under consideration does not require significant increase of the model. The method is applied to small examples of network consisting of a small number of nodes and a small number of their connections. The results give the network reliability. They identify equipment, which is to be carefully maintained in order that the network reliability is not reduced, and equipment, which is a candidate for redundancy, as this would improve network reliability significantly. (author)

  9. Assessing high reliability via Bayesian approach and accelerated tests

    International Nuclear Information System (INIS)

    Erto, Pasquale; Giorgio, Massimiliano

    2002-01-01

    Sometimes the assessment of very high reliability levels is difficult for the following main reasons: - the high reliability level of each item makes it impossible to obtain, in a reasonably short time, a sufficient number of failures; - the high cost of the high reliability items to submit to life tests makes it unfeasible to collect enough data for 'classical' statistical analyses. In the above context, this paper presents a Bayesian solution to the problem of estimation of the parameters of the Weibull-inverse power law model, on the basis of a limited number (say six) of life tests, carried out at different stress levels, all higher than the normal one. The over-stressed (i.e. accelerated) tests allow the use of experimental data obtained in a reasonably short time. The Bayesian approach enables one to reduce the required number of failures adding to the failure information the available a priori engineers' knowledge. This engineers' involvement conforms to the most advanced management policy that aims at involving everyone's commitment in order to obtain total quality. A Monte Carlo study of the non-asymptotic properties of the proposed estimators and a comparison with the properties of maximum likelihood estimators closes the work

  10. Reliability assessment of distribution power systems including distributed generations

    International Nuclear Information System (INIS)

    Megdiche, M.

    2004-12-01

    Nowadays, power systems have reached a good level of reliability. Nevertheless, considering the modifications induced by the connections of small independent producers to distribution networks, there's a need to assess the reliability of these new systems. Distribution networks present several functional characteristics, highlighted by the qualitative study of the failures, as dispersed loads at several places, variable topology and some electrotechnical phenomena which must be taken into account to model the events that can occur. The adopted reliability calculations method is Monte Carlo simulations, the probabilistic method most powerful and most flexible to model complex operating of the distribution system. We devoted a first part on the case of a 20 kV feeder to which a cogeneration unit is connected. The method was applied to a software of stochastic Petri nets simulations. Then a second part related to the study of a low voltage power system supplied by dispersed generations. Here, the complexity of the events required to code the method in an environment of programming allowing the use of power system calculations (load flow, short-circuit, load shedding, management of units powers) in order to analyse the system state for each new event. (author)

  11. Seismic reliability assessment methodology for CANDU concrete containment structures

    International Nuclear Information System (INIS)

    Stephens, M.J.; Nessim, M.A.; Hong, H.P.

    1995-05-01

    A study was undertaken to develop a reliability-based methodology for the assessment of existing CANDU concrete containment structures with respect to seismic loading. The focus of the study was on defining appropriate specified values and partial safety factors for earthquake loading and resistance parameters. Key issues addressed in the work were the identification of an approach to select design earthquake spectra that satisfy consistent safety levels, and the use of structure-specific data in the evaluation of structural resistance. (author). 23 refs., 9 tabs., 15 figs

  12. A Hierarchal Risk Assessment Model Using the Evidential Reasoning Rule

    Directory of Open Access Journals (Sweden)

    Xiaoxiao Ji

    2017-02-01

    Full Text Available This paper aims to develop a hierarchical risk assessment model using the newly-developed evidential reasoning (ER rule, which constitutes a generic conjunctive probabilistic reasoning process. In this paper, we first provide a brief introduction to the basics of the ER rule and emphasize the strengths for representing and aggregating uncertain information from multiple experts and sources. Further, we discuss the key steps of developing the hierarchical risk assessment framework systematically, including (1 formulation of risk assessment hierarchy; (2 representation of both qualitative and quantitative information; (3 elicitation of attribute weights and information reliabilities; (4 aggregation of assessment information using the ER rule and (5 quantification and ranking of risks using utility-based transformation. The proposed hierarchical risk assessment framework can potentially be implemented to various complex and uncertain systems. A case study on the fire/explosion risk assessment of marine vessels demonstrates the applicability of the proposed risk assessment model.

  13. Reliable scar scoring system to assess photographs of burn patients.

    Science.gov (United States)

    Mecott, Gabriel A; Finnerty, Celeste C; Herndon, David N; Al-Mousawi, Ahmed M; Branski, Ludwik K; Hegde, Sachin; Kraft, Robert; Williams, Felicia N; Maldonado, Susana A; Rivero, Haidy G; Rodriguez-Escobar, Noe; Jeschke, Marc G

    2015-12-01

    Several scar-scoring scales exist to clinically monitor burn scar development and maturation. Although scoring scars through direct clinical examination is ideal, scars must sometimes be scored from photographs. No scar scale currently exists for the latter purpose. We modified a previously described scar scale (Yeong et al., J Burn Care Rehabil 1997) and tested the reliability of this new scale in assessing burn scars from photographs. The new scale consisted of three parameters as follows: scar height, surface appearance, and color mismatch. Each parameter was assigned a score of 1 (best) to 4 (worst), generating a total score of 3-12. Five physicians with burns training scored 120 representative photographs using the original and modified scales. Reliability was analyzed using coefficient of agreement, Cronbach alpha, intraclass correlation coefficient, variance, and coefficient of variance. Analysis of variance was performed using the Kruskal-Wallis test. Color mismatch and scar height scores were validated by analyzing actual height and color differences. The intraclass correlation coefficient, the coefficient of agreement, and Cronbach alpha were higher for the modified scale than those of the original scale. The original scale produced more variance than that in the modified scale. Subanalysis demonstrated that, for all categories, the modified scale had greater correlation and reliability than the original scale. The correlation between color mismatch scores and actual color differences was 0.84 and between scar height scores and actual height was 0.81. The modified scar scale is a simple, reliable, and useful scale for evaluating photographs of burn patients. Copyright © 2015 Elsevier Inc. All rights reserved.

  14. Modern biogeochemistry environmental risk assessment

    CERN Document Server

    Bashkin, Vladimir N

    2006-01-01

    Most books deal mainly with various technical aspects of ERA description and calculationsAims at generalizing the modern ideas of both biogeochemical and environmental risk assessment during recent yearsAims at supplementing the existing books by providing a modern understanding of mechanisms that are responsible for the ecological risk for human beings and ecosystem

  15. Risk assessment future cash flows

    OpenAIRE

    Chachina H. G.

    2012-01-01

    This article is about risk assessment in planning future cash flows. Discount rate in DCF-model must include four factors: risk cash flow, inflation, value of investments, turnover assets. This has an influence net present value cash flow and make his incomparable.

  16. Test reactor risk assessment methodology

    International Nuclear Information System (INIS)

    Jennings, R.H.; Rawlins, J.K.; Stewart, M.E.

    1976-04-01

    A methodology has been developed for the identification of accident initiating events and the fault modeling of systems, including common mode identification, as these methods are applied in overall test reactor risk assessment. The methods are exemplified by a determination of risks to a loss of primary coolant flow in the Engineering Test Reactor

  17. Anthropic Risk Assessment on Biodiversity

    Science.gov (United States)

    Piragnolo, M.; Pirotti, F.; Vettore, A.; Salogni, G.

    2013-01-01

    This paper presents a methodology for risk assessment of anthropic activities on habitats and species. The method has been developed for Veneto Region, in order to simplify and improve the quality of EIA procedure (VINCA). Habitats and species, animals and plants, are protected by European Directive 92/43/EEC and 2009/147/EC but they are subject at hazard due to pollution produced by human activities. Biodiversity risks may conduct to deterioration and disturbance in ecological niches, with consequence of loss of biodiversity. Ecological risk assessment applied on Natura 2000 network, is needed to best practice of management and monitoring of environment and natural resources. Threats, pressure and activities, stress and indicators may be managed by geodatabase and analysed using GIS technology. The method used is the classic risk assessment in ecological context, and it defines the natural hazard as influence, element of risk as interference and vulnerability. Also it defines a new parameter called pressure. It uses risk matrix for the risk analysis on spatial and temporal scale. The methodology is qualitative and applies the precautionary principle in environmental assessment. The final product is a matrix which excludes the risk and could find application in the development of a territorial information system.

  18. Cloud computing assessing the risks

    CERN Document Server

    Carstensen, Jared; Golden, Bernard

    2012-01-01

    Cloud Computing: Assessing the risks answers these questions and many more. Using jargon-free language and relevant examples, analogies and diagrams, it is an up-to-date, clear and comprehensive guide the security, governance, risk, and compliance elements of Cloud Computing.

  19. Improving pandemic influenza risk assessment

    Science.gov (United States)

    Assessing the pandemic risk posed by specific non-human influenza A viruses remains a complex challenge. As influenza virus genome sequencing becomes cheaper, faster and more readily available, the ability to predict pandemic potential from sequence data could transform pandemic influenza risk asses...

  20. Human reliability

    International Nuclear Information System (INIS)

    Embrey, D.E.

    1987-01-01

    Concepts and techniques of human reliability have been developed and are used mostly in probabilistic risk assessment. For this, the major application of human reliability assessment has been to identify the human errors which have a significant effect on the overall safety of the system and to quantify the probability of their occurrence. Some of the major issues within human reliability studies are reviewed and it is shown how these are applied to the assessment of human failures in systems. This is done under the following headings; models of human performance used in human reliability assessment, the nature of human error, classification of errors in man-machine systems, practical aspects, human reliability modelling in complex situations, quantification and examination of human reliability, judgement based approaches, holistic techniques and decision analytic approaches. (UK)

  1. Reliability assessment using Bayesian networks. Case study on quantative reliability estimation of a software-based motor protection relay

    International Nuclear Information System (INIS)

    Helminen, A.; Pulkkinen, U.

    2003-06-01

    In this report a quantitative reliability assessment of motor protection relay SPAM 150 C has been carried out. The assessment focuses to the methodological analysis of the quantitative reliability assessment using the software-based motor protection relay as a case study. The assessment method is based on Bayesian networks and tries to take the full advantage of the previous work done in a project called Programmable Automation System Safety Integrity assessment (PASSI). From the results and experiences achieved during the work it is justified to claim that the assessment method presented in the work enables a flexible use of qualitative and quantitative elements of reliability related evidence in a single reliability assessment. At the same time the assessment method is a concurrent way of reasoning one's beliefs and references about the reliability of the system. Full advantage of the assessment method is taken when using the method as a way to cultivate the information related to the reliability of software-based systems. The method can also be used as a communicational instrument in a licensing process of software-based systems. (orig.)

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

    Science.gov (United States)

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

    2009-01-01

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

  3. A Novel Risk Scoring System Reliably Predicts Readmission Following Pancreatectomy

    Science.gov (United States)

    Valero, Vicente; Grimm, Joshua C.; Kilic, Arman; Lewis, Russell L.; Tosoian, Jeffrey J.; He, Jin; Griffin, James; Cameron, John L.; Weiss, Matthew J.; Vollmer, Charles M.; Wolfgang, Christopher L.

    2015-01-01

    Background Postoperative readmissions have been proposed by Medicare as a quality metric and may impact provider reimbursement. Since readmission following pancreatectomy is common, we sought to identify factors associated with readmission in order to establish a predictive risk scoring system (RSS). Study Design A retrospective analysis of 2,360 pancreatectomies performed at nine, high-volume pancreatic centers between 2005 and 2011 was performed. Forty-five factors strongly associated with readmission were identified. To derive and validate a RSS, the population was randomly divided into two cohorts in a 4:1 fashion. A multivariable logistic regression model was constructed and scores were assigned based on the relative odds ratio of each independent predictor. A composite Readmission After Pancreatectomy (RAP) score was generated and then stratified to create risk groups. Results Overall, 464 (19.7%) patients were readmitted within 90-days. Eight pre- and postoperative factors, including prior myocardial infarction (OR 2.03), ASA Class ≥ 3 (OR 1.34), dementia (OR 6.22), hemorrhage (OR 1.81), delayed gastric emptying (OR 1.78), surgical site infection (OR 3.31), sepsis (OR 3.10) and short length of stay (OR 1.51), were independently predictive of readmission. The 32-point RAP score generated from the derivation cohort was highly predictive of readmission in the validation cohort (AUC 0.72). The low (0-3), intermediate (4-7) and high risk (>7) groups correlated to 11.7%, 17.5% and 45.4% observed readmission rates, respectively (preadmission following pancreatectomy. Identification of patients with increased risk of readmission using the RAP score will allow efficient resource allocation aimed to attenuate readmission rates. It also has potential to serve as a new metric for comparative research and quality assessment. PMID:25797757

  4. Technologies for Assessing Behavioral and Cognitive Markers of Suicide Risk

    Science.gov (United States)

    2017-10-01

    assessing behavioral and cognitive markers of risk for suicide among U.S. Army National Guard personnel. Journal of Environmental Research and Public Policy...effective ways to prevent injury and death from suicide • No reliable method for predicting suicide risk in military personnel • Behavioral (e.g...AWARD NUMBER: W81XWH-15-1-0632 TITLE: Technologies for Assessing Behavioral and Cognitive Markers of Suicide Risk PRINCIPAL INVESTIGATOR: Brian

  5. Pathology and risk assessment

    International Nuclear Information System (INIS)

    Anon.

    1976-01-01

    Programs for providing basic data for use in evaluating the hazard to man from exposure to radiation and other energy-related pollutants are reviewed. A computer program was developed that takes the existing mortality and fertility data on a given population and applies dose-response coefficients and estimated increments of exposure to chemical or radioactive effluents and derives the excess deaths by age and sex for 5-year intervals. The program was used in an analysis of the health effects of airborne coal combustion effluents. Preliminary results are reported from a study of the influence of products of fossil fuel combustion on the spontaneous activity patterns and daily metabolic cycles of mice as a factor of age, environment, and genetic constitution. Preliminary results are reported from studies on the early and late effects of polycyclic hydrocarbons on the immune competence of mice. Studies to determine the risk to human populations from radionuclides released to the environment from nuclear energy facilities use relative toxicity and dose response data from laboratory animals of different body size and life span and comparisons of the effects of internal exposure with those of external exposure to fission neutrons or gamma sources

  6. Application of nonparametric statistics to material strength/reliability assessment

    International Nuclear Information System (INIS)

    Arai, Taketoshi

    1992-01-01

    An advanced material technology requires data base on a wide variety of material behavior which need to be established experimentally. It may often happen that experiments are practically limited in terms of reproducibility or a range of test parameters. Statistical methods can be applied to understanding uncertainties in such a quantitative manner as required from the reliability point of view. Statistical assessment involves determinations of a most probable value and the maximum and/or minimum value as one-sided or two-sided confidence limit. A scatter of test data can be approximated by a theoretical distribution only if the goodness of fit satisfies a test criterion. Alternatively, nonparametric statistics (NPS) or distribution-free statistics can be applied. Mathematical procedures by NPS are well established for dealing with most reliability problems. They handle only order statistics of a sample. Mathematical formulas and some applications to engineering assessments are described. They include confidence limits of median, population coverage of sample, required minimum number of a sample, and confidence limits of fracture probability. These applications demonstrate that a nonparametric statistical estimation is useful in logical decision making in the case a large uncertainty exists. (author)

  7. Mechanical reliability assessment of optical fibres in Radiation environments

    International Nuclear Information System (INIS)

    Van Uffelen, M.

    2006-01-01

    After more than two decades of intensive research and even some pioneering applications in space, optical fibres are now finding their way in various radiation environments, including both fission and future fusion nuclear-power plants, and high-energy physics experiments. For example, next to distributed monitoring applications of large nuclear infrastructures, fibre-optics can also be used for data communications during maintenance operations in the reactor vessel of the future ITER (International Thermonuclear Experimental Reactor), or for plasma diagnostics applications during operation of the reactor. These maintenance and diagnostics tasks require the optical fibres to withstand extremely high doses of radiation, up to MGy dose levels and temperatures above 150 degrees Celsius. The reliability assessment of fibre-optic systems for their qualification in nuclear environments often requires to meet stringent radiation tolerance levels. The majority of (usually accelerated) radiation assessments have so far focused on optical properties, such as wavelength-dependent radiation induced attenuation and radio-luminescence. The relation of these radiation effects with the fabrication methods and other environmental parameters has been the subject of years of research. Only a few results are available on the long-term evolution of mechanical properties of irradiated optical fibres. As a first step towards understanding the long-term reliability of fibre-optic composite cables in hostile radiation environments, we therefore performed dynamic fatigue tests with different commercial-grade optical fibres, both multi-mode and single-mode types

  8. Avalanche risk assessment in Russia

    Science.gov (United States)

    Komarov, Anton; Seliverstov, Yury; Sokratov, Sergey; Glazovskaya, Tatiana; Turchaniniva, Alla

    2017-04-01

    The avalanche prone area covers about 3 million square kilometers or 18% of total area of Russia and pose a significant problem in most mountain regions of the country. The constant growth of economic activity, especially in the North Caucasus region and therefore the increased avalanche hazard lead to the demand of the large-scale avalanche risk assessment methods development. Such methods are needed for the determination of appropriate avalanche protection measures as well as for economic assessments during all stages of spatial planning of the territory. The requirement of natural hazard risk assessments is determined by the Federal Law of Russian Federation. However, Russian Guidelines (SP 11-103-97; SP 47.13330.2012) are not clearly presented concerning avalanche risk assessment calculations. A great size of Russia territory, vast diversity of natural conditions and large variations in type and level of economic development of different regions cause significant variations in avalanche risk values. At the first stage of research the small scale avalanche risk assessment was performed in order to identify the most common patterns of risk situations and to calculate full social risk and individual risk. The full social avalanche risk for the territory of country was estimated at 91 victims. The area of territory with individual risk values lesser then 1×10(-6) covers more than 92 % of mountain areas of the country. Within these territories the safety of population can be achieved mainly by organizational activities. Approximately 7% of mountain areas have 1×10(-6) - 1×10(-4) individual risk values and require specific mitigation measures to protect people and infrastructure. Territories with individual risk values 1×10(-4) and above covers about 0,1 % of the territory and include the most severe and hazardous mountain areas. The whole specter of mitigation measures is required in order to minimize risk. The future development of such areas is not recommended

  9. Risk-based Optimization and Reliability Levels of Coastal Structures

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Burcharth, H. F.

    Identification of optimum reliability levels for coastal structures is considered. A class of breakwaters is considered where no human injuries can be expected in cases of failure. The optimum reliability level is identified by minimizing the total costs over the service life of the structure, in...... on the minimumcost reliability levels is investigated for different values of the real rate of interest, the service lifetime, the downtime costs due to malfunction and the decommission costs.......Identification of optimum reliability levels for coastal structures is considered. A class of breakwaters is considered where no human injuries can be expected in cases of failure. The optimum reliability level is identified by minimizing the total costs over the service life of the structure...

  10. Risk-based Optimization and Reliability Levels of Coastal Structures

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Burcharth, Hans F.

    2005-01-01

     Identification of optimum reliability levels for coastal structures is considered. A class of breakwaters is considered where no human injuries can be expected in cases of failure. The optimum reliability level is identified by minimizing the total costs over the service life of the structure, i...... on the minimumcost reliability levels is investigated for different values of the real rate of interest, the service lifetime, the downtime costs due to malfunction and the decommission costs....... Identification of optimum reliability levels for coastal structures is considered. A class of breakwaters is considered where no human injuries can be expected in cases of failure. The optimum reliability level is identified by minimizing the total costs over the service life of the structure...

  11. Caries risk assessment in children

    DEFF Research Database (Denmark)

    Twetman, S

    2016-01-01

    PURPOSE: To summarise the findings of recent systematic reviews (SR) covering caries risk assessment in children, updated with recent primary studies. METHODS: A search for relevant papers published 2012-2014 was conducted in electronic databases. The systematic reviews were quality assessed...... displayed a high risk of bias. CONCLUSIONS: Based on the present summary of literature, it may be concluded: (1) a caries risk assessment should be carried out at the child's first dental visit and reassessments should be done during childhood (D); (2) multivariate models display a better accuracy than...... the use of single predictors and this is especially true for preschool children (C); (3) there is no clearly superior method to predict future caries and no evidence to support the use of one model, program, or technology before the other (C); and (4) the risk category should be linked to appropriate...

  12. Assessing Risk of Innovation

    International Nuclear Information System (INIS)

    Allgood, GO

    2001-01-01

    Today's manufacturing systems and equipment must perform at levels thought impossible a decade ago. Companies must push operations, quality, and efficiencies to unprecedented levels while holding down costs. In this new economy, companies must be concerned with market shares, equity growth, market saturation, and profit. U.S. manufacturing is no exception and is a prime example of businesses forced to adapt to constant and rapid changes in customer needs and product mixes, giving rise to the term ''Agile Manufacturing''. The survival and ultimate success of the American Manufacturing economy may depend upon its ability to create, innovate, and quickly assess the impact that new innovations will have on its business practices. Given the need for flexibility, companies need proven methods to predict and measure the impact that new technologies and strategies will have on overall plant performance from an enterprise perspective. The Value-Derivative Model provides a methodology and approach to assess such impacts in terms of energy savings, production increases, quality impacts, emission reduction, and maintenance and operating costs as they relate to enabling and emerging technologies. This is realized by calculating a set of first order sensitivity parameters obtained from expanding a Taylor Series about the system's operating point. These sensitivity parameters are invariant economic and operational indicators that quantify the impact of any proposed technology in terms of material throughput, efficiency, energy usage, environmental effects, and costs. These parameters also provide a mechanism to define metrics and performance measures that can be qualified in terms of real economic impact. Value-Derivative Analysis can be applied across all manufacturing and production segments of our economy and has found specific use in steel and textiles. Where economic models give the cost of conducting a business, Value-Derivative Analysis provides the cost to conduct

  13. Risk assessment research and technology assessment

    International Nuclear Information System (INIS)

    Albach, H.; Schade, D.; Sinn, H.

    1991-01-01

    The concepts and approaches for technology assessment, the targets and scientific principles, as well as recognizable deficits and recommendations concerning purposeful strategies for the promotion of this research field require a dialog between those concerned. Conception, deficits, and the necessary measures for risk assessment research and technology assessment were discussed as well as ethical aspects. The problematic nature of using organisms altered through genetic engineering in the open land, traffic and transport, site restoration, nuclear energy, and isotope applications were subjects particularly dealt with. (DG) [de

  14. Reliability assessment of serviceability performance of braced retaining walls using a neural network approach

    Science.gov (United States)

    Goh, A. T. C.; Kulhawy, F. H.

    2005-05-01

    In urban environments, one major concern with deep excavations in soft clay is the potentially large ground deformations in and around the excavation. Excessive movements can damage adjacent buildings and utilities. There are many uncertainties associated with the calculation of the ultimate or serviceability performance of a braced excavation system. These include the variabilities of the loadings, geotechnical soil properties, and engineering and geometrical properties of the wall. A risk-based approach to serviceability performance failure is necessary to incorporate systematically the uncertainties associated with the various design parameters. This paper demonstrates the use of an integrated neural network-reliability method to assess the risk of serviceability failure through the calculation of the reliability index. By first performing a series of parametric studies using the finite element method and then approximating the non-linear limit state surface (the boundary separating the safe and failure domains) through a neural network model, the reliability index can be determined with the aid of a spreadsheet. Two illustrative examples are presented to show how the serviceability performance for braced excavation problems can be assessed using the reliability index.

  15. Risk assessment for transport operations

    International Nuclear Information System (INIS)

    Appleton, P.R.; Miles, J.C.

    1990-01-01

    The world-wide safety of the transport of radioactive material is based on the IAEA Transport Regulations. Risk assessment can provide quantitative data to help in the demonstration, understanding and improvement of the effectiveness of the Regulations in assuring safety. In this Paper the methodology, data and computer codes necessary and available for transport risk assessment are reviewed. Notable examples of assessments carried out over the past 15 years are briefly described along with current research, and the benefits and limitations of the techniques are discussed. (author)

  16. Reliability assessment using degradation models: bayesian and classical approaches

    Directory of Open Access Journals (Sweden)

    Marta Afonso Freitas

    2010-04-01

    Full Text Available Traditionally, reliability assessment of devices has been based on (accelerated life tests. However, for highly reliable products, little information about reliability is provided by life tests in which few or no failures are typically observed. Since most failures arise from a degradation mechanism at work for which there are characteristics that degrade over time, one alternative is monitor the device for a period of time and assess its reliability from the changes in performance (degradation observed during that period. The goal of this article is to illustrate how degradation data can be modeled and analyzed by using "classical" and Bayesian approaches. Four methods of data analysis based on classical inference are presented. Next we show how Bayesian methods can also be used to provide a natural approach to analyzing degradation data. The approaches are applied to a real data set regarding train wheels degradation.Tradicionalmente, o acesso à confiabilidade de dispositivos tem sido baseado em testes de vida (acelerados. Entretanto, para produtos altamente confiáveis, pouca informação a respeito de sua confiabilidade é fornecida por testes de vida no quais poucas ou nenhumas falhas são observadas. Uma vez que boa parte das falhas é induzida por mecanismos de degradação, uma alternativa é monitorar o dispositivo por um período de tempo e acessar sua confiabilidade através das mudanças em desempenho (degradação observadas durante aquele período. O objetivo deste artigo é ilustrar como dados de degradação podem ser modelados e analisados utilizando-se abordagens "clássicas" e Bayesiana. Quatro métodos de análise de dados baseados em inferência clássica são apresentados. A seguir, mostramos como os métodos Bayesianos podem também ser aplicados para proporcionar uma abordagem natural à análise de dados de degradação. As abordagens são aplicadas a um banco de dados real relacionado à degradação de rodas de trens.

  17. Establishing the Appropriate Attributes in Current Human Reliability Assessment Techniques for Nuclear Safety

    International Nuclear Information System (INIS)

    Bowie, Jane; Munley, Gary; Dang, Vinh; Wreathall, John; Bye, Andreas; Cooper, Susan; Marble, Julie; Peters, Sean; Xing, Jing; Fauchille, Veronique; Fiset, Jean Yves; Haage, Monica; Johanson, Gunnar; Jung, Won Dae; Kim, Jaewhan; Lee, Seung Jung; Kubicek, Jan; Le Bot, Pierre; Pesme, Helene; Preischl, Wolfgang; Salway, Alice; Amri, Abdallah; Lamarre, Greg; White, Andrew; )

    2015-03-01

    This report presents the results of a joint task of the Working Groups on Risk Assessment (WGRISK) and on Human and Organisational Factors (WGHOF) of the OECD/NEA CSNI, to identify desirable attributes of Human Reliability Assessment (HRA) methods, and to evaluate a range of HRA methods used in OECD member countries against those attributes. The purpose of this project is to provide information that will support regulators and operators of nuclear facilities when making judgements about the appropriateness of HRA methods for conducting assessments in support of Probabilistic Safety Assessments (PSA). The task was performed by an international team of Human Factors, HRA and PSA experts from a broad range of OECD member countries. As in other reviews of HRA methods, the study did not set out to recommend or promote the use of any particular HRA method. Rather the study aims to identify the strengths and limitations of commonly used and developing methods to aid those responsible for production of HRAs in selecting appropriate tools for specific HRA applications. The study also aims to assist regulators when making judgements on the appropriateness of the application of an HRA technique within nuclear-related probabilistic safety assessments. The report is aimed at practitioners in the field of human reliability assessment, human factors, and risk assessment more generally

  18. Nuclear Computerized Library for Assessing Reactor Reliability (NUCLARR): Volume 1, Summary description

    International Nuclear Information System (INIS)

    Gertman, D.I.; Gilmore, W.E.; Galyean, W.J.; Groh, M.R.; Gentillon, C.D.; Gilbert, B.G.

    1988-02-01

    A data management system has been implemented which supports a variety of risk-related analyses and provides a repository of hardware component failure and human error probability data to the risk analyst. The Nuclear Computerized Library for Assessing Reactor Reliability, NUCLARR, is an interactive, graphically oriented system which resides on a personal computer (PC) or PC-compatible environment. An overview of the data management system, including a description of data collection, specification, data structure, and taxonomies, is presented in Volume I of this report. Programming activities, procedures for processing data, user's guide, and hard copy data manual are presented in Volumes II through V

  19. Reliability worth assessment of radial systems with distributed generation

    OpenAIRE

    Bellart Llavall, Francesc Xavier

    2010-01-01

    With recent advances in technology, utilities generation (DG) on the distribution systems. Reliability worth is very important in power system planning and operation. Having a DG ensures reli increase the reliability worth. This research project presents the study of a radial distribution system and the impact of placing DG in order to increase the reliability worth. where a DG have to be placed. The reliability improvement is measured by different reliability indices tha...

  20. Assessment of microelectronics packaging for high temperature, high reliability applications

    Energy Technology Data Exchange (ETDEWEB)

    Uribe, F.

    1997-04-01

    This report details characterization and development activities in electronic packaging for high temperature applications. This project was conducted through a Department of Energy sponsored Cooperative Research and Development Agreement between Sandia National Laboratories and General Motors. Even though the target application of this collaborative effort is an automotive electronic throttle control system which would be located in the engine compartment, results of this work are directly applicable to Sandia`s national security mission. The component count associated with the throttle control dictates the use of high density packaging not offered by conventional surface mount. An enabling packaging technology was selected and thermal models defined which characterized the thermal and mechanical response of the throttle control module. These models were used to optimize thick film multichip module design, characterize the thermal signatures of the electronic components inside the module, and to determine the temperature field and resulting thermal stresses under conditions that may be encountered during the operational life of the throttle control module. Because the need to use unpackaged devices limits the level of testing that can be performed either at the wafer level or as individual dice, an approach to assure a high level of reliability of the unpackaged components was formulated. Component assembly and interconnect technologies were also evaluated and characterized for high temperature applications. Electrical, mechanical and chemical characterizations of enabling die and component attach technologies were performed. Additionally, studies were conducted to assess the performance and reliability of gold and aluminum wire bonding to thick film conductor inks. Kinetic models were developed and validated to estimate wire bond reliability.

  1. Risk assessment and the environment

    International Nuclear Information System (INIS)

    Fisk, D.J.

    1992-01-01

    This paper reviews the use of risk assessment techniques in the field of environment protection. I will argue that in some important instances the development of environment policy has been a source of fruitful development of a risk based methodologies. In other cases the importation of risk assessment techniques has proved much more problematic. As the scope of environmental regulation increases so does the possibility of inconsistent and arbitrary solutions to problems. The need for a more systematic approach to the development of environmental regulation has never been stronger, so it is important to understand the reasons for the mixed success of risk assessment. This applies equally to those nations with long traditions of the regulation of private sector industry and those just beginning on this course. The way ahead may be to extend our ideas of how to express risk and uncertainty. Some of the recent cause celebres of environment policy show this challenge very clearly. As an example, this paper will look at the problem of assessing the risk of man-made climate change

  2. Risk assessment and the environment

    Energy Technology Data Exchange (ETDEWEB)

    Fisk, D J [Department of the Environment (United Kingdom)

    1992-07-01

    This paper reviews the use of risk assessment techniques in the field of environment protection. I will argue that in some important instances the development of environment policy has been a source of fruitful development of a risk based methodologies. In other cases the importation of risk assessment techniques has proved much more problematic. As the scope of environmental regulation increases so does the possibility of inconsistent and arbitrary solutions to problems. The need for a more systematic approach to the development of environmental regulation has never been stronger, so it is important to understand the reasons for the mixed success of risk assessment. This applies equally to those nations with long traditions of the regulation of private sector industry and those just beginning on this course. The way ahead may be to extend our ideas of how to express risk and uncertainty. Some of the recent cause celebres of environment policy show this challenge very clearly. As an example, this paper will look at the problem of assessing the risk of man-made climate change.

  3. Assessing Your Weight and Health Risk

    Science.gov (United States)

    ... Health Professional Resources Assessing Your Weight and Health Risk Assessment of weight and health risk involves using ... risk for developing obesity-associated diseases or conditions. Risk Factors for Health Topics Associated With Obesity Along ...

  4. Reliability of a semi-quantitative method for dermal exposure assessment (DREAM)

    NARCIS (Netherlands)

    Wendel de Joode, B. van; Hemmen, J.J. van; Meijster, T.; Major, V.; London, L.; Kromhout, H.

    2005-01-01

    Valid and reliable semi-quantitative dermal exposure assessment methods for epidemiological research and for occupational hygiene practice, applicable for different chemical agents, are practically nonexistent. The aim of this study was to assess the reliability of a recently developed

  5. Cut set-based risk and reliability analysis for arbitrarily interconnected networks

    Science.gov (United States)

    Wyss, Gregory D.

    2000-01-01

    Method for computing all-terminal reliability for arbitrarily interconnected networks such as the United States public switched telephone network. The method includes an efficient search algorithm to generate minimal cut sets for nonhierarchical networks directly from the network connectivity diagram. Efficiency of the search algorithm stems in part from its basis on only link failures. The method also includes a novel quantification scheme that likewise reduces computational effort associated with assessing network reliability based on traditional risk importance measures. Vast reductions in computational effort are realized since combinatorial expansion and subsequent Boolean reduction steps are eliminated through analysis of network segmentations using a technique of assuming node failures to occur on only one side of a break in the network, and repeating the technique for all minimal cut sets generated with the search algorithm. The method functions equally well for planar and non-planar networks.

  6. Modeling human intention formation for human reliability assessment

    International Nuclear Information System (INIS)

    Woods, D.D.; Roth, E.M.; Pople, H. Jr.

    1988-01-01

    This paper describes a dynamic simulation capability for modeling how people form intentions to act in nuclear power plant emergency situations. This modeling tool, Cognitive Environment Simulation or CES, was developed based on techniques from artificial intelligence. It simulates the cognitive processes that determine situation assessment and intention formation. It can be used to investigate analytically what situations and factors lead to intention failures, what actions follow from intention failures (e.g. errors of omission, errors of commission, common mode errors), the ability to recover from errors or additional machine failures, and the effects of changes in the NPP person machine system. One application of the CES modeling environment is to enhance the measurement of the human contribution to risk in probabilistic risk assessment studies. (author)

  7. Aspects regarding explosion risk assessment

    Directory of Open Access Journals (Sweden)

    Părăian Mihaela

    2017-01-01

    Full Text Available Explosive risk occurs in all activities involving flammable substances in the form of gases, vapors, mists or dusts which, in mixture with air, can generate an explosive atmosphere. As explosions can cause human losses and huge material damage, the assessment of the explosion risk and the establishment of appropriate measures to reduce it to acceptable levels according to the standards and standards in force is of particular importance for the safety and health of people and goods.There is no yet a recognized method of assessing the explosion risk, but regardless of the applied method, the likelihood of an explosive atmosphere occurrence has to be determined, together with the occurrence of an efficient ignition source and the magnitude of foreseeable consequences. In assessment processes, consequences analysis has a secondary importance since it’s likely that explosions would always involve considerable damage, starting from important material damages and up to human damages that could lead to death.The purpose of the work is to highlight the important principles and elements to be taken into account for a specific risk assessment. An essential element in assessing the risk of explosion in workplaces where explosive atmospheres may occur is technical installations and personal protective equipment (PPE that must be designed, manufactured, installed and maintained so that they cannot generate a source of ignition. Explosion prevention and protection requirements are governed by specific norms and standards, and a main part of the explosion risk assessment is related to the assessment of the compliance of the equipment / installation with these requirements.

  8. Risk assessment and nuclear power

    International Nuclear Information System (INIS)

    Bodansky, D.

    1982-01-01

    The range of risk perceptions involving nuclear power is so great that there is little hope of bridging extreme positions, but a consensus based upon reasoned discussion among uncommitted people could determine a sensible path. Our concerns over the uncertainties of risk assessment have made it increasingly difficult to make responsible decisions fast enough to deal with modern needs. The result is an immobility in energy matters that can point to a 2% reduction in oil use as its only triumph. The risk of nuclear war as a result of military action over energy issues suggests to some that the solution is to abolish nuclear power (however impractical) and to others that a rapid spread of nuclear power will eliminate energy as an incentive for war. If nuclear war is the major risk to consider, risk assessments need to include the risks of war, as well as those of carbon dioxide buildup and socio-economic disruptions, all of which loom larger than the risks of nuclear-plant accidents. Energy choices should be aimed at diminishing these major risks, even if they include the use of nuclear power. 26 references

  9. Sudden Cardiac Arrest (SCA) Risk Assessment

    Science.gov (United States)

    ... HRS Find a Specialist Share Twitter Facebook SCA Risk Assessment Sudden Cardiac Arrest (SCA) occurs abruptly and without ... people of all ages and health conditions. Start Risk Assessment The Sudden Cardiac Arrest (SCA) Risk Assessment Tool ...

  10. Modified Tuck Jump Assessment: Reliability and Training of Raters

    Directory of Open Access Journals (Sweden)

    Craig A. Smith, Nicole J. Chimera, Monica R. Lininger, Meghan Warren

    2017-09-01

    Full Text Available We are writing with regard to “Intra- and inter-rater reliability of the modified tuck jump assessment,” by Fort-Vanmeerhaeghe et al. (2017 published in the Journal of Sports Science & Medicine. The authors reported on the reliability of the modified Tuck Jump Assessment (TJA. The purpose of the article was twofold: to introduce a new scoring methodology and to report on the interrater and intrarater reliability. The authors found the modified TJA to have excellent interrater reliability (ICC = 0.94, 95% CI = 0.88-0.97 and intrarater reliability (rater 1 ICC = 0.94, 95% CI = 0.88-0.9; rater 2 ICC = 0.96, 95% CI = 0.92-0.98 with experienced raters (n = 2 in a sample of 24 elite volleyball athletes. Overall, we found the study to be well conducted and valuable to the field of injury screening; however, the study did not adequately explain how the raters were trained in the modified TJA to improve consistency of scoring, or the modifications of the individual flaw “excessive contact noise at landing.” This information is necessary to improve the clinical utility of the TJA and direct future reliability studies. The TJA has been changed at least three times in the literature: from the initial introduction (Myer et al., 2006 to the most referenced and detailed protocol (Myer et al., 2011 to the publication under discussion (Fort-Vanmeerhaeghe et al., 2017. The initial test protocol was based upon clinical expertise and has evolved over time as new research emerged and problems arose with the original TJA. Initially, the TJA was scored on a visual analog scale (Myer et al., 2006, changed to a dichotomous scale (0 for no flaw or 1 for flaw present (Myer et al., 2011 and most recently modified using an ordinal scale (Fort-Vanmeerhaeghe et al., 2017. A significant disparity in the reported interrater and intrarater reliability arose with the dichotomously scored TJA, between those involved in the development of the TJA (Herrington et al., 2013

  11. Reliability and validity of the Farsi version of the standardized assessment of personality-abbreviated scale

    Directory of Open Access Journals (Sweden)

    Maryam Sepehri

    2017-06-01

    Full Text Available Introduction: A short screening tool for high-risk individuals with personality disorder (PD is useful both for clinicians and researchers. The aim of this study was to assess the validity and reliability of the Farsi version of the Standardized Assessment of Personality-Abbreviated Scale (SAPAS. Methods: The original English version of the SAPAS questionnaire was translated into Farsi, and then, translated back into English by two professionals. A survey was then conducted using the questionnaire on 150 clients of primary health care centers in Tabriz, Iran. A total of 235 medical students were also studied for the reliability assessment of the questionnaire. The SAPAS was compared to the short form of Minnesota Multiphasic Personality Inventory (MMPI. The data analysis was performed using receiver operating characteristic (ROC curve technique, operating characteristic for diagnostic efficacy, Cronbach's alpha, and test-retest for reliability evaluation. Results: We found an area under the curve (AUC of 0.566 [95% confidence intervals (CI: 0.455-0.677]; sensitivity of 0.89 and specificity of 0.26 at the cut-off score of 2 and higher. The total Cronbach's alpha coefficient was 0.38 and Cohen's kappa ranged between 0.5 and 0.8. Conclusion: The current study showed that the Farsi version of the SAPAS was relatively less efficient, in term of validity and reliability, in the screening of PD in the population.

  12. Usage models in reliability assessment of software-based systems

    Energy Technology Data Exchange (ETDEWEB)

    Haapanen, P.; Pulkkinen, U. [VTT Automation, Espoo (Finland); Korhonen, J. [VTT Electronics, Espoo (Finland)

    1997-04-01

    This volume in the OHA-project report series deals with the statistical reliability assessment of software based systems on the basis of dynamic test results and qualitative evidence from the system design process. Other reports to be published later on in the OHA-project report series will handle the diversity requirements in safety critical software-based systems, generation of test data from operational profiles and handling of programmable automation in plant PSA-studies. In this report the issues related to the statistical testing and especially automated test case generation are considered. The goal is to find an efficient method for building usage models for the generation of statistically significant set of test cases and to gather practical experiences from this method by applying it in a case study. The scope of the study also includes the tool support for the method, as the models may grow quite large and complex. (32 refs., 30 figs.).

  13. Usage models in reliability assessment of software-based systems

    International Nuclear Information System (INIS)

    Haapanen, P.; Pulkkinen, U.; Korhonen, J.

    1997-04-01

    This volume in the OHA-project report series deals with the statistical reliability assessment of software based systems on the basis of dynamic test results and qualitative evidence from the system design process. Other reports to be published later on in the OHA-project report series will handle the diversity requirements in safety critical software-based systems, generation of test data from operational profiles and handling of programmable automation in plant PSA-studies. In this report the issues related to the statistical testing and especially automated test case generation are considered. The goal is to find an efficient method for building usage models for the generation of statistically significant set of test cases and to gather practical experiences from this method by applying it in a case study. The scope of the study also includes the tool support for the method, as the models may grow quite large and complex. (32 refs., 30 figs.)

  14. 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

  15. Approaches of data combining for reliability assessments with taking into account the priority of data application

    International Nuclear Information System (INIS)

    Zelenyj, O.V.; Pecheritsa, A.V.

    2004-01-01

    Based upon the available experience on assessments of risk from Ukrainian NPP's operational events as well as on results of State review of PSA studies for pilot units it should be noted that historical information on domestic NPP's operation is not always available or used properly under implementation of mentioned activities. The several approaches for combining of available generic and specific information for reliability parameters assessment (taking into account the priority of data application) are briefly described in the article along with some recommendations how to apply those approaches

  16. Ecological Risk Assessment of Genetically Modified Higher Plants (GMHP)

    DEFF Research Database (Denmark)

    Kjær, C.; Damgaard, C.; Kjellsson, G.

    Preface This publication is a first version of a manual identifying the data needs for ecological risk assessment of genetically modified higher plants (GMHP). It is the intention of the authors to stimulate further discussion of what data are needed in order to conduct a proper ecological risk...... of the project Biotechnology: elements in environmental risk assessment of genetically modified plants. December 1999 Christian Kjær Introduction In ecological risk assessment of transgenic plants, information on a wide range of subjects is needed for an effective and reliable assessment procedure...... in the amendment to the directive. This report suggests a structured way to identify the type of data needed to perform a sound ecological risk assessment for genetically modified higher plants (GMHP). The identified data types are intended to support the evaluation of the following risks: risk of invasion...

  17. Assessment of Data Reliability of Wireless Sensor Network for Bioinformatics

    Directory of Open Access Journals (Sweden)

    Ting Dong

    2017-09-01

    Full Text Available As a focal point of biotechnology, bioinformatics integrates knowledge from biology, mathematics, physics, chemistry, computer science and information science. It generally deals with genome informatics, protein structure and drug design. However, the data or information thus acquired from the main areas of bioinformatics may not be effective. Some researchers combined bioinformatics with wireless sensor network (WSN into biosensor and other tools, and applied them to such areas as fermentation, environmental monitoring, food engineering, clinical medicine and military. In the combination, the WSN is used to collect data and information. The reliability of the WSN in bioinformatics is the prerequisite to effective utilization of information. It is greatly influenced by factors like quality, benefits, service, timeliness and stability, some of them are qualitative and some are quantitative. Hence, it is necessary to develop a method that can handle both qualitative and quantitative assessment of information. A viable option is the fuzzy linguistic method, especially 2-tuple linguistic model, which has been extensively used to cope with such issues. As a result, this paper introduces 2-tuple linguistic representation to assist experts in giving their opinions on different WSNs in bioinformatics that involve multiple factors. Moreover, the author proposes a novel way to determine attribute weights and uses the method to weigh the relative importance of different influencing factors which can be considered as attributes in the assessment of the WSN in bioinformatics. Finally, an illustrative example is given to provide a reasonable solution for the assessment.

  18. Data driven CAN node reliability assessment for manufacturing system

    Science.gov (United States)

    Zhang, Leiming; Yuan, Yong; Lei, Yong

    2017-01-01

    The reliability of the Controller Area Network(CAN) is critical to the performance and safety of the system. However, direct bus-off time assessment tools are lacking in practice due to inaccessibility of the node information and the complexity of the node interactions upon errors. In order to measure the mean time to bus-off(MTTB) of all the nodes, a novel data driven node bus-off time assessment method for CAN network is proposed by directly using network error information. First, the corresponding network error event sequence for each node is constructed using multiple-layer network error information. Then, the generalized zero inflated Poisson process(GZIP) model is established for each node based on the error event sequence. Finally, the stochastic model is constructed to predict the MTTB of the node. The accelerated case studies with different error injection rates are conducted on a laboratory network to demonstrate the proposed method, where the network errors are generated by a computer controlled error injection system. Experiment results show that the MTTB of nodes predicted by the proposed method agree well with observations in the case studies. The proposed data driven node time to bus-off assessment method for CAN networks can successfully predict the MTTB of nodes by directly using network error event data.

  19. Human reliability assessment on the basis of operating experience

    International Nuclear Information System (INIS)

    Straeter, O.

    1997-01-01

    For development of methodology, available models for qualitative assessment of human errors (e.g. by Swain, Hacker, Rasmussen) and a variety of known systematic approaches for quantitiative assessment of inadequate human action (e.g. THERP, ASEP, HCR, SLIM) were taken as a basis to establish a job specification, which in turn was used for developing a method for acquisition, characterisation and evaluation of errors. This method encompasses the two processes of event analysis and event evaluation: The first step comprises analysis of events by analysis of information describing the conditions and scenarios of relevance to the inadequate human action examined. In addition to the description of process sequences, information is taken into account on possible conditions that may bring about failure. As an assessment of human reliability requires manifold approaches for evaluation, a connectionistic procedure was developed for evaluation of the compilation of events based on a debate about various approaches from the domain of artificial intelligence (AI). This procedure yields both qualitative and quantitative information through a homogenous approach. (orig./GL) [de

  20. Feasibility and reliability of a newly developed antenatal risk score card in routine care

    NARCIS (Netherlands)

    E. Birnie; E.A.P. Steegers; Drs. H.W. Torij; M.J. Veen; J. Poeran; G.J. Bonsel

    2015-01-01

    A population-based cross-sectional study (feasibility) and a cohort study (inter-rater reliability) to study in routine care the feasibility and inter-rater reliability of the Rotterdam Reproductive Risk Reduction risk score card (R4U), a new semi-quantitative score card for use during the antenatal

  1. Environmental Risk Assessment of Nanomaterials

    Science.gov (United States)

    Bayramov, A. A.

    In this paper, various aspects of modern nanotechnologies and, as a result, risks of nanomaterials impact on an environment are considered. This very brief review of the First International Conference on Material and Information Sciences in High Technologies (2007, Baku, Azerbaijan) is given. The conference presented many reports that were devoted to nanotechnology in biology and business for the developing World, formation of charged nanoparticles for creation of functional nanostructures, nanoprocessing of carbon nanotubes, magnetic and optical properties of manganese-phosphorus nanowires, ultra-nanocrystalline diamond films, and nanophotonics communications in Azerbaijan. The mathematical methods of simulation of the group, individual and social risks are considered for the purpose of nanomaterials risk reduction and remediation. Lastly, we have conducted studies at a plant of polymeric materials (and nanomaterials), located near Baku. Assessments have been conducted on the individual risk of person affection and constructed the map of equal isolines and zones of individual risk for a plant of polymeric materials (and nanomaterials).

  2. Probabilistic risk assessment: Number 219

    International Nuclear Information System (INIS)

    Bari, R.A.

    1985-01-01

    This report describes a methodology for analyzing the safety of nuclear power plants. A historical overview of plants in the US is provided, and past, present, and future nuclear safety and risk assessment are discussed. A primer on nuclear power plants is provided with a discussion of pressurized water reactors (PWR) and boiling water reactors (BWR) and their operation and containment. Probabilistic Risk Assessment (PRA), utilizing both event-tree and fault-tree analysis, is discussed as a tool in reactor safety, decision making, and communications. (FI)

  3. Impact of data source on travel time reliability assessment.

    Science.gov (United States)

    2014-08-01

    Travel time reliability measures are becoming an increasingly important input to the mobility and : congestion management studies. In the case of Maryland State Highway Administration, reliability : measures are key elements in the agencys Annual ...

  4. Cumulative trauma disorders in the upper extremities: reliability of the postural and repetitive risk-factors index.

    Science.gov (United States)

    James, C P; Harburn, K L; Kramer, J F

    1997-08-01

    This study addresses test-retest reliability of the Postural and Repetitive Risk-Factors Index (PRRI) for work-related upper body injuries. This assessment was developed by the present authors. A repeated measures design was used to assess the test-retest reliability of a videotaped work-site assessment of subjects' movements. Ten heavy users of video display terminals (VDTs) from a local banking industry participated in the study. The 10 subjects' movements were videotaped for 2 hours on each of 2 separate days, while working on-site at their VDTs. The videotaped assessment, which utilized known postural risk factors for developing musculoskeletal disorder, pain, and discomfort in heavy VDT users (ie, repetitiveness, awkward and static postures, and contraction time), was called the PRRI. The videotaped movement assessments were subsequently analyzed in 15-minute sessions (five sessions per 2-hour videotape, which produced a total of 10 sessions over the 2 testing days), and each session was chosen randomly from the videotape. The subjects' movements were given a postural risk score according to the criteria in the PRRI. Each subject was therefore tested a total of 10 times (ie, 10 sessions), over two days. The maximum PRRI score for both sides of the body was 216 points. Reliability coefficients (RCs) for the PRRI scores were calculated, and the reliability of any one session met the minimum criterion for excellent reliability, which was .75. A two-way analysis of variance (ANOVA) confirmed that there was no statistically significant difference between sessions (p < .05). Calculations using the standard error of measurement (SEM) indicated that an individual tested once, on one day and with a PRRI score of 25, required a change of at least 8 points in order to be confident that a true change in score had occurred. The significant results from the reliability tests indicated that the PRRI was a reliable measurement tool that could be used by occupational health

  5. Portfolio assessment during medical internships: How to obtain a reliable and feasible assessment procedure?

    Science.gov (United States)

    Michels, Nele R M; Driessen, Erik W; Muijtjens, Arno M M; Van Gaal, Luc F; Bossaert, Leo L; De Winter, Benedicte Y

    2009-12-01

    A portfolio is used to mentor and assess students' clinical performance at the workplace. However, students and raters often perceive the portfolio as a time-consuming instrument. In this study, we investigated whether assessment during medical internship by a portfolio can combine reliability and feasibility. The domain-oriented reliability of 61 double-rated portfolios was measured, using a generalisability analysis with portfolio tasks and raters as sources of variation in measuring the performance of a student. We obtained reliability (Phi coefficient) of 0.87 with this internship portfolio containing 15 double-rated tasks. The generalisability analysis showed that an acceptable level of reliability (Phi = 0.80) was maintained when the amount of portfolio tasks was decreased to 13 or 9 using one and two raters, respectively. Our study shows that a portfolio can be a reliable method for the assessment of workplace learning. The possibility of reducing the amount of tasks or raters while maintaining a sufficient level of reliability suggests an increase in feasibility of portfolio use for both students and raters.

  6. Nuclear computerized library for assessing reactor reliability (NUCLARR): User's guide: Part 3, NUCLARR system description

    International Nuclear Information System (INIS)

    Gilmore, W.E.; Gentillon, C.D.; Gertman, D.I.; Beers, G.H.; Galyean, W.J.; Gilbert, B.G.

    1988-06-01

    The Nuclear Computerized Library for Assessing Reactor Reliability (NUCLARR) is an automated data base management system for processing and storing human error probability and hardware component failure data. The NUCLARR system software resides on an IBM (or compatible) personal micro-computer. NUCLARR can be used by the end user to furnish data inputs for both human and hardware reliability analysis in support of a variety of risk assessment activities. The NUCLARR system is documented in a five-volume series of reports. Volume IV of this series is the User's Guide for operating the NUCLARR software and is presented in three parts. This document, Part 3: NUCLARR System Description, provides an in-depth discussion of the design characteristics and special features of the NUCLARR software. Part 3 also presents the organization of the data base structures and techniques used to manipulate the data

  7. Evidential analytic hierarchy process dependence assessment methodology in human reliability analysis

    International Nuclear Information System (INIS)

    Chen, Lu Yuan; Zhou, Xinyi; Xiao, Fuyuan; Deng, Yong; Mahadevan, Sankaran

    2017-01-01

    In human reliability analysis, dependence assessment is an important issue in risky large complex systems, such as operation of a nuclear power plant. Many existing methods depend on an expert's judgment, which contributes to the subjectivity and restrictions of results. Recently, a computational method, based on the Dempster-Shafer evidence theory and analytic hierarchy process, has been proposed to handle the dependence in human reliability analysis. The model can deal with uncertainty in an analyst's judgment and reduce the subjectivity in the evaluation process. However, the computation is heavy and complicated to some degree. The most important issue is that the existing method is in a positive aspect, which may cause an underestimation of the risk. In this study, a new evidential analytic hierarchy process dependence assessment methodology, based on the improvement of existing methods, has been proposed, which is expected to be easier and more effective

  8. Nuclear computerized library for assessing reactor reliability (NUCLARR): Part 2, Guide to operations: User's guide

    International Nuclear Information System (INIS)

    Gilmore, W.E.; Gentillon, C.D.; Gertman, D.I.; Beers, G.H.; Galyean, W.J.; Gilbert, B.G.

    1988-06-01

    The Nuclear Computerized Library for Assessing Reactor Reliability (NUCLARR) is an automated data base management system for processing and storing human error probability and hardware component failure data. The NUCLARR system software resides on an IBM (or compatible) personal micro-computer. NUCLARR can be used by the end user to furnish data inputs for both human and hardware reliability analysis in support of a variety of risk assessment activities. The NUCLARR system is documented in a five-volume series of reports. Volume IV of this series is the User's Guide for operating the NUCLARR software and is presented in three parts. This volume, Part 2: Guide to Operations, contains the instructions and basic procedures for using the NUCLARR software. Part 2 provides guidance and information for getting started, performing the desired functions, and making the most efficient use of the system's features

  9. Evidential Analytic Hierarchy Process Dependence Assessment Methodology in Human Reliability Analysis

    Directory of Open Access Journals (Sweden)

    Luyuan Chen

    2017-02-01

    Full Text Available In human reliability analysis, dependence assessment is an important issue in risky large complex systems, such as operation of a nuclear power plant. Many existing methods depend on an expert's judgment, which contributes to the subjectivity and restrictions of results. Recently, a computational method, based on the Dempster–Shafer evidence theory and analytic hierarchy process, has been proposed to handle the dependence in human reliability analysis. The model can deal with uncertainty in an analyst's judgment and reduce the subjectivity in the evaluation process. However, the computation is heavy and complicated to some degree. The most important issue is that the existing method is in a positive aspect, which may cause an underestimation of the risk. In this study, a new evidential analytic hierarchy process dependence assessment methodology, based on the improvement of existing methods, has been proposed, which is expected to be easier and more effective.

  10. Evidential analytic hierarchy process dependence assessment methodology in human reliability analysis

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Lu Yuan; Zhou, Xinyi; Xiao, Fuyuan; Deng, Yong [School of Computer and Information Science, Southwest University, Chongqing (China); Mahadevan, Sankaran [School of Engineering, Vanderbilt University, Nashville (United States)

    2017-02-15

    In human reliability analysis, dependence assessment is an important issue in risky large complex systems, such as operation of a nuclear power plant. Many existing methods depend on an expert's judgment, which contributes to the subjectivity and restrictions of results. Recently, a computational method, based on the Dempster-Shafer evidence theory and analytic hierarchy process, has been proposed to handle the dependence in human reliability analysis. The model can deal with uncertainty in an analyst's judgment and reduce the subjectivity in the evaluation process. However, the computation is heavy and complicated to some degree. The most important issue is that the existing method is in a positive aspect, which may cause an underestimation of the risk. In this study, a new evidential analytic hierarchy process dependence assessment methodology, based on the improvement of existing methods, has been proposed, which is expected to be easier and more effective.

  11. Human Reliability in Probabilistic Safety Assessments; Fiabilidad Humana en los Analisis Probabilisticos de Seguridad

    Energy Technology Data Exchange (ETDEWEB)

    Nunez Mendez, J

    1989-07-01

    Nowadays a growing interest in environmental aspects is detected in our country. It implies an assessment of the risk involved in the industrial processes and installations in order to determine if those are into the acceptable limits. In these safety assessments, among which PSA (Probabilistic Safety Assessments), can be pointed out the role played by the human being in the system is one of the more relevant subjects (This relevance has been demonstrated in the accidents happened) . However, in Spain there aren't manuals specifically dedicated to asses the human contribution to risk in the frame of PSAs. This report aims to improve this situation providing: a) a theoretical background to help the reader in the understanding of the nature of the human error, b) a quid to carry out a Human Reliability Analysis and c) a selected overview of the techniques and methodologies currently applied in this area. (Author) 20 refs.

  12. Human Reliability in Probabilistic Safety Assessments; Fiabilidad Humana en los Analisis Probabilisticos de Seguridad

    Energy Technology Data Exchange (ETDEWEB)

    Nunez Mendez, J.

    1989-07-01

    Nowadays a growing interest in environmental aspects is detected in our country. It implies an assessment of the risk involved in the industrial processes and installations in order to determine if those are into the acceptable limits. In these safety assessments, among which PSA (Probabilistic Safety Assessments), can be pointed out the role played by the human being in the system is one of the more relevant subjects (This relevance has been demonstrated in the accidents happened) . However, in Spain there aren't manuals specifically dedicated to asses the human contribution to risk in the frame of PSAs. This report aims to improve this situation providing: a) a theoretical background to help the reader in the understanding of the nature of the human error, b) a quid to carry out a Human Reliability Analysis and c) a selected overview of the techniques and methodologies currently applied in this area. (Author) 20 refs.

  13. Environmental Risk Assessment Strategy for Nanomaterials

    Directory of Open Access Journals (Sweden)

    Janeck J. Scott‐Fordsmand

    2017-10-01

    Full Text Available An Environmental Risk Assessment (ERA for nanomaterials (NMs is outlined in this paper. Contrary to other recent papers on the subject, the main data requirements, models and advancement within each of the four risk assessment domains are described, i.e., in the: (i materials, (ii release, fate and exposure, (iii hazard and (iv risk characterisation domains. The material, which is obviously the foundation for any risk assessment, should be described according to the legislatively required characterisation data. Characterisation data will also be used at various levels within the ERA, e.g., exposure modelling. The release, fate and exposure data and models cover the input for environmental distribution models in order to identify the potential (PES and relevant exposure scenarios (RES and, subsequently, the possible release routes, both with regard to which compartment(s NMs are distributed in line with the factors determining the fate within environmental compartment. The initial outcome in the risk characterisation will be a generic Predicted Environmental Concentration (PEC, but a refined PEC can be obtained by applying specific exposure models for relevant media. The hazard information covers a variety of representative, relevant and reliable organisms and/or functions, relevant for the RES and enabling a hazard characterisation. The initial outcome will be hazard characterisation in test systems allowing estimating a Predicted No-Effect concentration (PNEC, either based on uncertainty factors or on a NM adapted version of the Species Sensitivity Distributions approach. The risk characterisation will either be based on a deterministic risk ratio approach (i.e., PEC/PNEC or an overlay of probability distributions, i.e., exposure and hazard distributions, using the nano relevant models.

  14. Environmental Risk Assessment Strategy for Nanomaterials.

    Science.gov (United States)

    Scott-Fordsmand, Janeck J; Peijnenburg, Willie J G M; Semenzin, Elena; Nowack, Bernd; Hunt, Neil; Hristozov, Danail; Marcomini, Antonio; Irfan, Muhammad-Adeel; Jiménez, Araceli Sánchez; Landsiedel, Robert; Tran, Lang; Oomen, Agnes G; Bos, Peter M J; Hund-Rinke, Kerstin

    2017-10-19

    An Environmental Risk Assessment (ERA) for nanomaterials (NMs) is outlined in this paper. Contrary to other recent papers on the subject, the main data requirements, models and advancement within each of the four risk assessment domains are described, i.e., in the: (i) materials, (ii) release, fate and exposure, (iii) hazard and (iv) risk characterisation domains. The material, which is obviously the foundation for any risk assessment, should be described according to the legislatively required characterisation data. Characterisation data will also be used at various levels within the ERA, e.g., exposure modelling. The release, fate and exposure data and models cover the input for environmental distribution models in order to identify the potential (PES) and relevant exposure scenarios (RES) and, subsequently, the possible release routes, both with regard to which compartment(s) NMs are distributed in line with the factors determining the fate within environmental compartment. The initial outcome in the risk characterisation will be a generic Predicted Environmental Concentration (PEC), but a refined PEC can be obtained by applying specific exposure models for relevant media. The hazard information covers a variety of representative, relevant and reliable organisms and/or functions, relevant for the RES and enabling a hazard characterisation. The initial outcome will be hazard characterisation in test systems allowing estimating a Predicted No-Effect concentration (PNEC), either based on uncertainty factors or on a NM adapted version of the Species Sensitivity Distributions approach. The risk characterisation will either be based on a deterministic risk ratio approach (i.e., PEC/PNEC) or an overlay of probability distributions, i.e., exposure and hazard distributions, using the nano relevant models.

  15. Integrating software reliability concepts into risk and reliability modeling of digital instrumentation and control systems used in nuclear power plants

    International Nuclear Information System (INIS)

    Arndt, S. A.

    2006-01-01

    As software-based digital systems are becoming more and more common in all aspects of industrial process control, including the nuclear power industry, it is vital that the current state of the art in quality, reliability, and safety analysis be advanced to support the quantitative review of these systems. Several research groups throughout the world are working on the development and assessment of software-based digital system reliability methods and their applications in the nuclear power, aerospace, transportation, and defense industries. However, these groups are hampered by the fact that software experts and probabilistic safety assessment experts view reliability engineering very differently. This paper discusses the characteristics of a common vocabulary and modeling framework. (authors)

  16. Risk assessment using probabilistic standards

    International Nuclear Information System (INIS)

    Avila, R.

    2004-01-01

    A core element of risk is uncertainty represented by plural outcomes and their likelihood. No risk exists if the future outcome is uniquely known and hence guaranteed. The probability that we will die some day is equal to 1, so there would be no fatal risk if sufficiently long time frame is assumed. Equally, rain risk does not exist if there was 100% assurance of rain tomorrow, although there would be other risks induced by the rain. In a formal sense, any risk exists if, and only if, more than one outcome is expected at a future time interval. In any practical risk assessment we have to deal with uncertainties associated with the possible outcomes. One way of dealing with the uncertainties is to be conservative in the assessments. For example, we may compare the maximal exposure to a radionuclide with a conservatively chosen reference value. In this case, if the exposure is below the reference value then it is possible to assure that the risk is low. Since single values are usually compared; this approach is commonly called 'deterministic'. Its main advantage lies in the simplicity and in that it requires minimum information. However, problems arise when the reference values are actually exceeded or might be exceeded, as in the case of potential exposures, and when the costs for realizing the reference values are high. In those cases, the lack of knowledge on the degree of conservatism involved impairs a rational weighing of the risks against other interests. In this presentation we will outline an approach for dealing with uncertainties that in our opinion is more consistent. We will call it a 'fully probabilistic risk assessment'. The essence of this approach consists in measuring the risk in terms of probabilities, where the later are obtained from comparison of two probabilistic distributions, one reflecting the uncertainties in the outcomes and one reflecting the uncertainties in the reference value (standard) used for defining adverse outcomes. Our first aim

  17. A prospective study assessing agreement and reliability of a geriatric evaluation.

    Science.gov (United States)

    Locatelli, Isabella; Monod, Stéfanie; Cornuz, Jacques; Büla, Christophe J; Senn, Nicolas

    2017-07-19

    The present study takes place within a geriatric program, aiming at improving the diagnosis and management of geriatric syndromes in primary care. Within this program it was of prime importance to be able to rely on a robust and reproducible geriatric consultation to use as a gold standard for evaluating a primary care brief assessment tool. The specific objective of the present study was thus assessing the agreement and reliability of a comprehensive geriatric consultation. The study was conducted at the outpatient clinic of the Service of Geriatric Medicine, University of Lausanne, Switzerland. All community-dwelling older persons aged 70 years and above were eligible. Patients were excluded if they hadn't a primary care physician, they were unable to speak French, or they were already assessed by a geriatrician within the last 12 months. A set of 9 geriatricians evaluated 20 patients. Each patient was assessed twice within a 2-month delay. Geriatric consultations were based on a structured evaluation process, leading to rating the following geriatric conditions: functional, cognitive, visual, and hearing impairment, mood disorders, risk of fall, osteoporosis, malnutrition, and urinary incontinence. Reliability and agreement estimates on each of these items were obtained using a three-way Intraclass Correlation and a three-way Observed Disagreement index. The latter allowed a decomposition of overall disagreement into disagreements due to each source of error variability (visit, rater and random). Agreement ranged between 0.62 and 0.85. For most domains, geriatrician-related error variability explained an important proportion of disagreement. Reliability ranged between 0 and 0.8. It was poor/moderate for visual impairment, malnutrition and risk of fall, and good/excellent for functional/cognitive/hearing impairment, osteoporosis, incontinence and mood disorders. Six out of nine items of the geriatric consultation described in this study (functional

  18. A study on a reliability assessment methodology for the VHTR safety systems

    International Nuclear Information System (INIS)

    Lee, Hyung Sok

    2012-02-01

    The passive safety system of a 300MWt VHTR (Very High Temperature Reactor)which has attracted worldwide attention recently is actively considered for designing the improvement in the safety of the next generation nuclear power plant. The passive system functionality does not rely on an external source of the electrical support system,but on an intelligent use of the natural phenomena, such as convection, conduction, radiation, and gravity. It is not easy to evaluate quantitatively the reliability of the passive safety for the risk analysis considering the existing active system failure since the classical reliability assessment method could not be applicable. Therefore a new reliability methodology needs to be developed and applied for evaluating the reliability of the conceptual designed VHTR in this study. The preliminary evaluation and conceptualization are performed using the concept of the load and capacity theory related to the reliability physics model. The method of response surface method (RSM) is also utilized for evaluating the maximum temperature of nuclear fuel in this study. The significant variables and their correlation are considered for utilizing the GAMMA+ code. The proposed method might contribute to designing the new passive system of the VHTR

  19. Probabilistic risk assessment as an aid to risk management

    International Nuclear Information System (INIS)

    Garrick, B.J.

    1982-01-01

    Probabilistic risk assessments are providing important insights into nuclear power plant safety. Their value is two-fold: first as a means of quantifying nuclear plant risk including contributors to risk, and second as an aid to risk management. A risk assessment provides an analytical plant model that can be the basis for performing meaningful decision analyses for controlling safety. It is the aspect of quantitative risk management that makes probabilistic risk assessment an important technical discipline of the future

  20. Methodology for technical risk assessment

    International Nuclear Information System (INIS)

    Waganer, L.M.; Zuckerman, D.S.

    1983-01-01

    A methodology has been developed for and applied to the assessment of the technical risks associated with an evolving technology. This methodology, originally developed for fusion by K. W. Billman and F. R. Scott at EPRI, has been applied to assess the technical risk of a fuel system for a fusion reactor. Technical risk is defined as the risk that a particular technology or component which is currently under development will not achieve a set of required technical specifications (i.e. probability of failure). The individual steps in the technical risk assessment are summarized. The first step in this methodology is to clearly and completely quantify the technical requirements for the particular system being examined. The next step is to identify and define subsystems and various options which appear capable of achieving the required technical performance. The subsystem options are then characterized regarding subsystem functions, interface requirements with the subsystems and systems, important components, developmental obstacles and technical limitations. Key technical subsystem performance parameters are identified which directly or indirectly relate to the system technical specifications. Past, existing and future technical performance data from subsystem experts are obtained by using a Bayesian Interrogation technique. The input data is solicited in the form of probability functions. Thus the output performance of the system is expressed as probability functions

  1. Ecological risk assessment: Lessons learned?

    International Nuclear Information System (INIS)

    Anon.

    1993-01-01

    This conference was held November 14--18, 1993 in Houston, Texas for the purpose of providing a forum for exchange of state-of-the-art information on ecological risk assessment. This book is comprised of the abstracts of the presentations at this symposium. Individual abstracts have been processed separately for inclusion in the appropriate data bases

  2. Where You Live: Risk Assessment

    Science.gov (United States)

    Where you live page shows visitors to the risk assessment website how to contact their local regional office by state. Since these link to pages maintained by the local offices they will have the most up-to-date contact information.

  3. Designing reliable supply chain network with disruption risk

    Directory of Open Access Journals (Sweden)

    Ali Bozorgi Amiri

    2013-01-01

    Full Text Available Although supply chains disruptions rarely occur, their negative effects are prolonged and severe. In this paper, we propose a reliable capacitated supply chain network design (RSCND model by considering random disruptions in both distribution centers and suppliers. The proposed model determines the optimal location of distribution centers (DC with the highest reliability, the best plan to assign customers to opened DCs and assigns opened DCs to suitable suppliers with lowest transportation cost. In this study, random disruption occurs at the location, capacity of the distribution centers (DCs and suppliers. It is assumed that a disrupted DC and a disrupted supplier may lose a portion of their capacities, and the rest of the disrupted DC's demand can be supplied by other DCs. In addition, we consider shortage in DCs, which can occur in either normal or disruption conditions and DCs, can support each other in such circumstances. Unlike other studies in the extent of literature, we use new approach to model the reliability of DCs; we consider a range of reliability instead of using binary variables. In order to solve the proposed model for real-world instances, a Non-dominated Sorting Genetic Algorithm-II (NSGA-II is applied. Preliminary results of testing the proposed model of this paper on several problems with different sizes provide seem to be promising.

  4. Reliability assessment of restructured power systems using reliability network equivalent and pseudo-sequential simulation techniques

    International Nuclear Information System (INIS)

    Ding, Yi; Wang, Peng; Goel, Lalit; Billinton, Roy; Karki, Rajesh

    2007-01-01

    This paper presents a technique to evaluate reliability of a restructured power system with a bilateral market. The proposed technique is based on the combination of the reliability network equivalent and pseudo-sequential simulation approaches. The reliability network equivalent techniques have been implemented in the Monte Carlo simulation procedure to reduce the computational burden of the analysis. Pseudo-sequential simulation has been used to increase the computational efficiency of the non-sequential simulation method and to model the chronological aspects of market trading and system operation. Multi-state Markov models for generation and transmission systems are proposed and implemented in the simulation. A new load shedding scheme is proposed during generation inadequacy and network congestion to minimize the load curtailment. The IEEE reliability test system (RTS) is used to illustrate the technique. (author)

  5. A methodology for assessment seismic risk in PSAs

    International Nuclear Information System (INIS)

    Jae, Moo Sung

    2001-01-01

    This paper suggested a new framework for assessing seismic risk in PSAs. The framework used the concepts of requirement and achievement in the reliability physics. The quantified correlation which is a function of the requirement variable (hazard curve) and the achievement variable (fragility curve) results in a quantity, the unconditional frequency of exceeding a damage lelvel. This framework can be applied to any other external safety assessment, such as Fire and Flood Risk in PSAs

  6. An approach to risk assessment

    DEFF Research Database (Denmark)

    Simonsen, L.; Lund, S. P.; Hass, Ulla

    1998-01-01

    of Ministers with the task to propose criteria for neurotoxicity. Functional effects on the nervous system, such as reduction in memory and learning ability, decrease in attention, and alteration of behavior due to toxic chemicals in the environment is now being acknowledged as an important public health...... indicate that numerous persons are exposed in the working as well as in the general environment to several chemicals, for which almost no data on the effect on subtle neurophysiological functions are available. Development of an approach to risk assessment dealing with this problem is a major challenge...... in the nineties. Different approaches to risk assessment are discussed, the quality of the databases available for hazard assessment are evaluated, and the needs for further research are identified. (C) 1996 Intox Press, Inc....

  7. IRRAS, Integrated Reliability and Risk Analysis System for PC

    International Nuclear Information System (INIS)

    Russell, K.D.

    1995-01-01

    1 - Description of program or function: IRRAS4.16 is a program developed for the purpose of performing those functions necessary to create and analyze a complete Probabilistic Risk Assessment (PRA). This program includes functions to allow the user to create event trees and fault trees, to define accident sequences and basic event failure data, to solve system and accident sequence fault trees, to quantify cut sets, and to perform uncertainty analysis on the results. Also included in this program are features to allow the analyst to generate reports and displays that can be used to document the results of an analysis. Since this software is a very detailed technical tool, the user of this program should be familiar with PRA concepts and the methods used to perform these analyses. 2 - Method of solution: IRRAS4.16 is written entirely in MODULA-2 and uses an integrated commercial graphics package to interactively construct and edit fault trees. The fault tree solving methods used are industry recognized top down algorithms. For quantification, the program uses standard methods to propagate the failure information through the generated cut sets. 3 - Restrictions on the complexity of the problem: Due to the complexity of and the variety of ways a fault tree can be defined it is difficult to define limits on the complexity of the problem solved by this software. It is, however, capable of solving a substantial fault tree due to efficient methods. At this time, the software can efficiently solve problems as large as other software currently used on mainframe computers. Does not include source code

  8. Quantum chemistry in environmental pesticide risk assessment.

    Science.gov (United States)

    Villaverde, Juan J; López-Goti, Carmen; Alcamí, Manuel; Lamsabhi, Al Mokhtar; Alonso-Prados, José L; Sandín-España, Pilar

    2017-11-01

    The scientific community and regulatory bodies worldwide, currently promote the development of non-experimental tests that produce reliable data for pesticide risk assessment. The use of standard quantum chemistry methods could allow the development of tools to perform a first screening of compounds to be considered for the experimental studies, improving the risk assessment. This fact results in a better distribution of resources and in better planning, allowing a more exhaustive study of the pesticides and their metabolic products. The current paper explores the potential of quantum chemistry in modelling toxicity and environmental behaviour of pesticides and their by-products by using electronic descriptors obtained computationally. Quantum chemistry has potential to estimate the physico-chemical properties of pesticides, including certain chemical reaction mechanisms and their degradation pathways, allowing modelling of the environmental behaviour of both pesticides and their by-products. In this sense, theoretical methods can contribute to performing a more focused risk assessment of pesticides used in the market, and may lead to higher quality and safer agricultural products. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  9. 24 CFR 35.315 - Risk assessment.

    Science.gov (United States)

    2010-04-01

    ... 24 Housing and Urban Development 1 2010-04-01 2010-04-01 false Risk assessment. 35.315 Section 35... Provided by a Federal Agency Other Than HUD § 35.315 Risk assessment. Each owner shall complete a risk assessment in accordance with 40 CFR 745.227(d). Each risk assessment shall be completed in accordance with...

  10. Clinical assessment of dysphagia in neurodegeneration (CADN): development, validity and reliability of a bedside tool for dysphagia assessment.

    Science.gov (United States)

    Vogel, Adam P; Rommel, Natalie; Sauer, Carina; Horger, Marius; Krumm, Patrick; Himmelbach, Marc; Synofzik, Matthis

    2017-06-01

    Screening assessments for dysphagia are essential in neurodegenerative disease. Yet there are no purpose-built tools to quantify swallowing deficits at bedside or in clinical trials. A quantifiable, brief, easy to administer assessment that measures the impact of dysphagia and predicts the presence or absence of aspiration is needed. The Clinical Assessment of Dysphagia in Neurodegeneration (CADN) was designed by a multidisciplinary team (neurology, neuropsychology, speech pathology) validated against strict methodological criteria in two neurodegenerative diseases, Parkinson's disease (PD) and degenerative ataxia (DA). CADN comprises two parts, an anamnesis (part one) and consumption (part two). Two-thirds of patients were assessed using reference tests, the SWAL-QOL symptoms subscale (part one) and videofluoroscopic assessment of swallowing (part two). CADN has 11 items and can be administered and scored in an average of 7 min. Test-retest reliability was established using correlation and Bland-Altman plots. 125 patients with a neurodegenerative disease were recruited; 60 PD and 65 DA. Validity was established using ROC graphs and correlations. CADN has sensitivity of 79 and 84% and specificity 71 and 69% for parts one and two, respectively. Significant correlations with disease severity were also observed (p dysphagia symptomatology and risk of aspiration. The CADN is a reliable, valid, brief, quantifiable, and easily deployed assessment of swallowing in neurodegenerative disease. It is thus ideally suited for both clinical bedside assessment and future multicentre clinical trials in neurodegenerative disease.

  11. Reliability of a Skin Diagnostic Device in Assessing Hydration and Erythema.

    Science.gov (United States)

    Huimin, Koh; Rowledge, Alexandra M; Borzdynski, Caroline J; Miller, Charne; Frescos, Nicoletta; McKenzie, Gayle; Perry, Elizabeth; McGuiness, William

    2017-10-01

    To examine the reliability of a skin diagnostic device, the SD202 (Courage+Khazaka GmBH, Cologne, Germany), in assessing hydration and erythema of periwound skin and pressure injury-prone areas. Intrarater reliabilities from 3 cross-sectional and prospective studies are reported. Patients attending an outpatient, nurse-led wound dressing clinic (n = 16), a podiatrist-led high-risk foot clinic (n = 17), and residents (n = 38) at a single residential aged-care facility. Skin hydration and erythema levels assessed using the SD202. High internal consistency was maintained for consecutive skin hydration and erythema measures at a single point on the venous leg ulcer periwound (α > .996 and α > .970 for hydration and erythema, respectively) and for the pressure-prone areas of the sacrum (α > .916), right (α > .994) and left (α > .967) ischium, right (α > .989) and left (α > .916) trochanter, right (α > .985) and left (α > .992) calcaneus, and right (α > .991) and left (α > .990) lateral malleolus. High consistency was also found for the measures obtained at 4 different locations around the periwound for the venous leg ulcer (α > .935 and α > .870 for hydration and erythema, respectively). In diabetic foot ulcer assessment, acceptable internal consistency of hydration measures around the periwound was observed (α > .634). Internal consistency of erythema measures was variable, ranging from low to high reliability, particularly among predebridement measures. Using the protocols outlined in this study, the SD202 demonstrates high reliability for assessing skin hydration and erythema levels. It is possible that the SD202 can be used in clinical practice as an appropriate tool for skin hydration and erythema assessment.

  12. Risk assessment of radiation carcinogenesis

    International Nuclear Information System (INIS)

    Kai, Michiaki

    2012-01-01

    This commentary describes the radiation cancer risk assessed by international organizations other than ICRP, assessed for radon and for internal exposure, in the series from the aspect of radiation protection of explaining the assessments done until ICRP Pub. 103. Statistic significant increase of cancer formation is proved at higher doses than 100-200 mSv. At lower doses, with use of mathematical model, United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) reported the death probability due to the excess lifetime risk (ELR) at 100 mSv of 0.36-0.77% for solid tumors and 0.03-0.05% for leukemia, and NRC in US, the risk of exposure-induced prevalence and death (REID) per 100 thousands persons of 800 (male)/1,310 (female) and 410/610, respectively. Both are essentially based on findings in A-bomb survivors. The assessment for Rn is described here not on dose. UK and US analyses of pooled raw data in case control studies revealed the significant increase of lung cancer formation at as low level as 100 Bq Rn/m3. Their analyses also showed the significance of smoking, which had been realized as a confounding factor in risk analysis of Rn for uranium miners. The death probability until the age of 85 y was found to be 1.2 x 10 -4 in non-smokers and 24 x 10 -4 in smokers/ Working Level Month (WLM). Increased thyroid cancer incidence has been known in Chernobyl Accident, which is realized as a result of internal exposure of radioiodine; however, the relationship between the internal dose to thyroid and its cancer prevalence resembles that in the case of external exposure. There is no certain evidence against the concept that risk of internal exposure is similar to and/or lower than, the external one although assessment of the internal exposure risk accompanies uncertainty depending on the used model and ingested dose. International Commission on Radiological Protection (ICRP) recommendations hitherto have been important and precious despite

  13. Performance assessment - risk assessment vive la differences

    International Nuclear Information System (INIS)

    Nitschke, R.L.

    1997-01-01

    In the sister worlds of radioactive waste management disposal and environmental restoration, there are two similar processes and computational approaches for determining the acceptability of the proposed activities. While similar, these two techniques can lead to confusion and misunderstanding if the differences are not recognized and appreciated. In the case of radioactive waste management, the performance assessment process is used to determine compliance with certain prescribed 'performance objectives'. These objectives are designed to ensure that the disposal of radioactive (high-level, low-level, and/or transuranic) waste will be protective of human health and the environment. The environmental link is primarily through assuring protection of the groundwater as a resource. In the case of environmental restoration, the risk assessment process is used to determine the proper remedial action response, if any, for a past hazardous waste release. The process compares the 'no action' or 'leave as is' option with both carcinogenic and noncarcinogenic values for human health to determine the need for any action and to help to help determine just what the appropriate action would need to be. The impacts to the ecological system are evaluated in a slightly, different but similar fashion. Now the common objectives between these two processes notwithstanding. There are some key and fundamental differences that need to be answered that make direct comparisons or a common approach inappropriate. Failure to recognize this can lead to confusion and misunderstanding. This can be particularly problematic when one is faced with an active disposal facility located within the boundaries of an environmental restoration site as is the case at the Idaho National Engineering Laboratory (INEL). Through a critical evaluation of the performance assessment and risk assessment processes, highlighting both similarities and differences, it is hoped that greater understanding and appreciation

  14. Key attributes of the SAPHIRE risk and reliability analysis software for risk-informed probabilistic applications

    International Nuclear Information System (INIS)

    Smith, Curtis; Knudsen, James; Kvarfordt, Kellie; Wood, Ted

    2008-01-01

    The Idaho National Laboratory is a primary developer of probabilistic risk and reliability analysis (PRRA) tools, dating back over 35 years. Evolving from mainframe-based software, the current state-of-the-practice has led to the creation of the SAPHIRE software. Currently, agencies such as the Nuclear Regulatory Commission, the National Aeronautics and Aerospace Agency, the Department of Energy, and the Department of Defense use version 7 of the SAPHIRE software for many of their risk-informed activities. In order to better understand and appreciate the power of software as part of risk-informed applications, we need to recall that our current analysis methods and solution methods have built upon pioneering work done 30-40 years ago. We contrast this work with the current capabilities in the SAPHIRE analysis package. As part of this discussion, we provide information for both the typical features and special analysis capabilities, which are available. We also present the application and results typically found with state-of-the-practice PRRA models. By providing both a high-level and detailed look at the SAPHIRE software, we give a snapshot in time for the current use of software tools in a risk-informed decision arena

  15. RELEVANCE OF PROCESS RISK ASSESSMENT IN AIRLINES

    OpenAIRE

    Oksana G. Feoktistova; Igor K. Turkin; Sergey V. Barinov

    2017-01-01

    The notion of “the concept on assumed risk” that took over from the outdated concept of absolute security is analyzed, the increasing significance of operating risk assessment at the present stage is noted. Some basic risk assessment techniques are considered. Matrix technique of risk assessment is considered more thoroughly, and it may be used in risk assessment of airlines in the context of labour protection management system.The ability to correctly assess risks and develop appropriate pre...

  16. Human Reliability Assessments: Using the Past (Shuttle) to Predict the Future (Orion)

    Science.gov (United States)

    DeMott, Diana L.; Bigler, Mark A.

    2017-01-01

    NASA (National Aeronautics and Space Administration) Johnson Space Center (JSC) Safety and Mission Assurance (S&MA) uses two human reliability analysis (HRA) methodologies. The first is a simplified method which is based on how much time is available to complete the action, with consideration included for environmental and personal factors that could influence the human's reliability. This method is expected to provide a conservative value or placeholder as a preliminary estimate. This preliminary estimate or screening value is used to determine which placeholder needs a more detailed assessment. The second methodology is used to develop a more detailed human reliability assessment on the performance of critical human actions. This assessment needs to consider more than the time available, this would include factors such as: the importance of the action, the context, environmental factors, potential human stresses, previous experience, training, physical design interfaces, available procedures/checklists and internal human stresses. The more detailed assessment is expected to be more realistic than that based primarily on time available. When performing an HRA on a system or process that has an operational history, we have information specific to the task based on this history and experience. In the case of a Probabilistic Risk Assessment (PRA) that is based on a new design and has no operational history, providing a "reasonable" assessment of potential crew actions becomes more challenging. To determine what is expected of future operational parameters, the experience from individuals who had relevant experience and were familiar with the system and process previously implemented by NASA was used to provide the "best" available data. Personnel from Flight Operations, Flight Directors, Launch Test Directors, Control Room Console Operators, and Astronauts were all interviewed to provide a comprehensive picture of previous NASA operations. Verification of the

  17. Hypsarrhythmia assessment exhibits poor interrater reliability: a threat to clinical trial validity.

    Science.gov (United States)

    Hussain, Shaun A; Kwong, Grace; Millichap, John J; Mytinger, John R; Ryan, Nicole; Matsumoto, Joyce H; Wu, Joyce Y; Lerner, Jason T; Sankar, Raman

    2015-01-01

    Hypsarrhythmia is the classic interictal electroencephalographic pattern associated with infantile spasms, and characterized by high voltage, disorganization, and multifocal independent epileptiform discharges. Given this seemingly simple definition, one might expect excellent interrater reliability (IRR) in the identification of this pattern. Alternatively, it may be argued that assessments of voltage and disorganization are fairly subjective, and thus quite challenging in borderline cases. We sought to test the IRR of hypsarrhythmia assessment in a systematic fashion. Six blinded pediatric electroencephalographers from four centers reviewed 22 electroencephalography (EEG) samples from patients with infantile spasms. Each sample was 5 min in duration and included only wakefulness. Raters determined if each EEG was abnormal and if hypsarrhythmia was present/absent, and characterized relevant features: voltage, organization, epileptiform discharges, slowing, interictal attenuations, symmetry, and synchrony. In addition, raters indicated their level of confidence for each assessment. Multirater kappa statistics (κ) were calculated for the assessment of hypsarrhythmia and each feature. Although IRR was favorable in determining whether a study was normal or abnormal (κ=0.89), reliability was unfavorable for assessment of hypsarrhythmia (κ=0.40), modified hypsarrhythmia (κ=0.47), high voltage (κ=0.37), disorganization (κ=0.22), multifocal epileptiform discharges (κ=0.68), interictal voltage attenuations (κ=0.21), slowing (κ=0.20), asymmetry (κ=0.26), and asynchrony (κ=0.08). Despite generally unsatisfactory interrater agreement, raters consistently reported high confidence in assessments. This study contradicts the view that hypsarrhythmia assessment is straightforward. Even small variability in the identification of hypsarrhythmia has potentially deleterious consequences for clinical care, as its presence or absence impacts decisions to pursue high-risk and

  18. Reliability-based Assessment of Fatigue Life for Bridges

    DEFF Research Database (Denmark)

    Toft, Henrik Stensgaard; Sørensen, John Dalsgaard

    2012-01-01

    The reliability level for bridges is discussed based on a comparison of the reliability levels proposed and used by e.g. JCSS, ISO, NKB and Eurocodes. The influence of reserve capacity by which failure of a specific detail does not lead to structural collapse is investigated. The results show...

  19. Construction of Valid and Reliable Test for Assessment of Students

    Science.gov (United States)

    Osadebe, P. U.

    2015-01-01

    The study was carried out to construct a valid and reliable test in Economics for secondary school students. Two research questions were drawn to guide the establishment of validity and reliability for the Economics Achievement Test (EAT). It is a multiple choice objective test of five options with 100 items. A sample of 1000 students was randomly…

  20. Assessment of power reliability and improvement potential by using ...

    African Journals Online (AJOL)

    This paper presents the use of smart reclosers for improving reliability of a distribution system of one of the major cities of Ethiopia. As frequent power interruptions are posing a huge problem to the life of the people and the economy, finding a solution to the problem is very essential. Electric reliability has affected social well ...

  1. Risk assessment and societal choices

    Energy Technology Data Exchange (ETDEWEB)

    Otway, H J

    1975-02-15

    Many countries are experiencing a period in which traditional values are being questioned; plans for further technological progress are being met by a variety of demands for a closer examination of the benefits and risks of large-scale technologies. In this paper the concepts of risk assessment are presented and a model is proposed which illustrates the importance of socio-psychological mechanisms in the acceptance of technological risks. The research plan of the Joint IAEA/IIASA Research Project is outlined: this work is directed toward gaining an improved understanding of how societies judge the acceptability of technologies and how societal attitudes and anticipated responses may be better integrated into the decision-making process. Some preliminary results are reported. (author)

  2. Risk assessment and societal choices

    International Nuclear Information System (INIS)

    Otway, H.J.

    1975-01-01

    Many countries are experiencing a period in which traditional values are being questioned; plans for further technological progress are being met by a variety of demands for a closer examination of the benefits and risks of large-scale technologies. In this paper the concepts of risk assessment are presented and a model is proposed which illustrates the importance of socio-psychological mechanisms in the acceptance of technological risks. The research plan of the Joint IAEA/IIASA Research Project is outlined: this work is directed toward gaining an improved understanding of how societies judge the acceptability of technologies and how societal attitudes and anticipated responses may be better integrated into the decision-making process. Some preliminary results are reported. (author)

  3. Fire Risk Assessment in Germany

    International Nuclear Information System (INIS)

    Berg, H. P.

    2000-01-01

    Quantitative fire risk assessment can serve as an additional tool to assess the safety level of a nuclear power plant (NPP) and to set priorities for fire protection improvement measures. The recommended approach to be applied within periodic safety reviews of NPPs in Germany starts with a screening process providing critical fire zones in which a fully developed fire has the potential to both cause an initiating event and impair the function of at least one component or system critical to safety. The second step is to perform a quantitative analysis using a standard event tree has been developed with elements for fire initiation, ventilation of the room, fire detection, fire suppression, and fire propagation. In a final step, the fire induced frequency of initiating events, the main contributors and the calculated hazard state frequency for the fire event are determined. Results of the first quantitative fire risk studies performed in Germany are reported. (author)

  4. Hydrocarbons pipeline transportation risk assessment

    Science.gov (United States)

    Zanin, A. V.; Milke, A. A.; Kvasov, I. N.

    2018-04-01

    The pipeline transportation applying risks assessment issue in the arctic conditions is addressed in the paper. Pipeline quality characteristics in the given environment has been assessed. To achieve the stated objective, the pipelines mathematical model was designed and visualized by using the software product SOLIDWORKS. When developing the mathematical model the obtained results made possible to define the pipeline optimal characteristics for designing on the Arctic sea bottom. In the course of conducting the research the pipe avalanche collapse risks were examined, internal longitudinal and circular loads acting on the pipeline were analyzed, as well as the water impact hydrodynamic force was taken into consideration. The conducted calculation can contribute to the pipeline transport further development under the harsh climate conditions of the Russian Federation Arctic shelf territory.

  5. Reliability assessment of Indian Point Unit 3 containment structure

    International Nuclear Information System (INIS)

    Kawakami, J.; Hwang, H.; Chang, M.T.; Reich, M.

    1984-01-01

    In the current design criteria, the load combinations specified for design of concrete containment structures are in the deterministic formats. However, by applying the probability-based reliability method developed by BNL to the concrete containment structures designed according to the criteria, it is possible to evaluate the reliability levels implied in the current design criteria. For this purpose, the reliability analysis is applied to the Indian Point Unit No. 3 containment. The details of the containment structure such as the geometries and the rebar arrangements, etc., are taken from the working drawings and the final safety analysis reports. Three kinds of loads are considered in the reliability analysis. They are, dead load (D), accidental pressure due to a large LOCA (P), and earthquake ground acceleration (E). Reliability analysis of the containment subjected to all combinations of loads is performed. Results are presented in this report

  6. Reliability assessment of underground pipelines under the combined effect of active corrosion and residual stress

    International Nuclear Information System (INIS)

    Amirat, A.; Mohamed-Chateauneuf, A.; Chaoui, K.

    2006-01-01

    Lifetime management of underground pipelines is mandatory for safe hydrocarbon transmission and distribution systems. Reliability analysis is recognized as a powerful decision-making tool for risk-based design and maintenance. Both the residual stresses generated during the manufacturing process and in-service corrosion reduce the ability to resist internal and external loading. In this study, the residual stress distribution in large diameter pipes has been characterized experimentally in order to be coupled with the corrosion model. During the pipe lifetime, residual stress relaxation occurs due to the loss of pipe thickness as material layers are consumed by corrosion. The reliability-based assessment of residual stress effects is applied to underground pipelines under a roadway, with and without active corrosion. It has been found that the residual stress greatly increases the failure probability, especially in the early stage of the pipe lifetime

  7. Probabilistic risk assessment of HTGRs

    International Nuclear Information System (INIS)

    Fleming, K.N.; Houghton, W.J.; Hannaman, G.W.; Joksimovic, V.

    1980-08-01

    Probabilistic Risk Assessment methods have been applied to gas-cooled reactors for more than a decade and to HTGRs for more than six years in the programs sponsored by the US Department of Energy. Significant advancements to the development of PRA methodology in these programs are summarized as are the specific applications of the methods to HTGRs. Emphasis here is on PRA as a tool for evaluating HTGR design options. Current work and future directions are also discussed

  8. Probabilistic risk assessment of HTGRs

    International Nuclear Information System (INIS)

    Fleming, K.N.; Houghton, W.J.; Hannaman, G.W.; Joksimovic, V.

    1981-01-01

    Probabilistic Risk Assessment methods have been applied to gas-cooled reactors for more than a decade and to HTGRs for more than six years in the programs sponsored by the U.S. Department of Energy. Significant advancements to the development of PRA methodology in these programs are summarized as are the specific applications of the methods to HTGRs. Emphasis here is on PRA as a tool for evaluating HTGR design options. Current work and future directions are also discussed. (author)

  9. Transparent Global Seismic Hazard and Risk Assessment

    Science.gov (United States)

    Smolka, Anselm; Schneider, John; Pinho, Rui; Crowley, Helen

    2013-04-01

    Vulnerability to earthquakes is increasing, yet advanced reliable risk assessment tools and data are inaccessible to most, despite being a critical basis for managing risk. Also, there are few, if any, global standards that allow us to compare risk between various locations. The Global Earthquake Model (GEM) is a unique collaborative effort that aims to provide organizations and individuals with tools and resources for transparent assessment of earthquake risk anywhere in the world. By pooling data, knowledge and people, GEM acts as an international forum for collaboration and exchange, and leverages the knowledge of leading experts for the benefit of society. Sharing of data and risk information, best practices, and approaches across the globe is key to assessing risk more effectively. Through global projects, open-source IT development and collaborations with more than 10 regions, leading experts are collaboratively developing unique global datasets, best practice, open tools and models for seismic hazard and risk assessment. Guided by the needs and experiences of governments, companies and citizens at large, they work in continuous interaction with the wider community. A continuously expanding public-private partnership constitutes the GEM Foundation, which drives the collaborative GEM effort. An integrated and holistic approach to risk is key to GEM's risk assessment platform, OpenQuake, that integrates all above-mentioned contributions and will become available towards the end of 2014. Stakeholders worldwide will be able to calculate, visualise and investigate earthquake risk, capture new data and to share their findings for joint learning. Homogenized information on hazard can be combined with data on exposure (buildings, population) and data on their vulnerability, for loss assessment around the globe. Furthermore, for a true integrated view of seismic risk, users can add social vulnerability and resilience indices to maps and estimate the costs and benefits

  10. Uncertainties in risk assessment and decision making

    International Nuclear Information System (INIS)

    Starzec, Peter; Purucker, Tom; Stewart, Robert

    2008-02-01

    confidence interval under different assumptions regarding the data structure. The results stress the importance to invoke statistical methods and also illustrate how the choice of a wrong methodology may affect the quality of risk assessment and foundations for decision making. The uncertainty in assessing the volume of contaminated soil was shown to be dependant only to a low extent on the interpolation technique used for the specific case study analyzed. It is, however, expected that the uncertainty may increase significantly, if more restrictive risk criteria (lower guideline value) are applied. Despite a possible low uncertainty in assessing the contaminated soil volume, the uncertainty in its localization can be substantial. Based on the demo example presented, it comes out that the risk-based input for decision on soil treatment may vary depending on what assumptions were adopted during interpolation process. Uncertainty in an ecological exposure model with regard to the moving pattern of a receptor in relation till spatial distribution of contaminant has been demonstrated by studies on pronghorn (Antilocapra americana). The results from numerical simulations show that a lack in knowledge on the receptor moving routes may bring about substantial uncertainty in exposure assessment. The presented concept is mainly applicable for 'mobile' receptors on relatively large areas. A number of statistical definitions/methods/concepts are presented in the report of which some are not elaborated on in detail, while readers are referred to proper literature. The mail goal with the study has been rather to shed more light on aspects related to uncertainty in risk assessment and to demonstrate potential consequences of wrong approach than to provide readers with formal guideline and recommendations. However, the outcome from the study will hopefully contribute to the further work on novel approaches towards more reliable risk assessments

  11. Reliability assessment of ballistic jump squats and bench throws.

    Science.gov (United States)

    Alemany, Joseph A; Pandorf, Clay E; Montain, Scott J; Castellani, John W; Tuckow, Alexander P; Nindl, Bradley C

    2005-02-01

    The purpose of this investigation was to determine the test-retest reliability and coefficient of variation of 2 novel physical performance tests. Ten healthy men (22.0 +/- 3.0 years, 87.0 +/- 8.0 kg, 20.0 +/- 5.0% body fat) performed 30 continuous and dynamic jump squats (JS) and bench throws (BT) on 4 separate occasions. The movements were performed under loaded conditions utilizing 30% of subject's predetermined 1 repetition maximum in the back squat and bench press. Mean power (MP; W), peak power (PP; W), mean velocity (MV; m.s(-1)), peak velocity (PV; m.s(-1)), and total work (TW; J) were assessed using a ballistic measurement system (Innervations Inc., Muncie, IN). Data were analyzed using repeated measures analysis of variance with Duncan's post hoc test when mean differences were p < or = 0.05. Intraclass correlation coefficient (ICC) and within-subject coefficient of variation (CV%) were also calculated. All values are presented as mean +/- SE. BT variables were statistically similar across the 4 sessions: MP (350.0 +/- 13.9 W), PP (431.4 +/- 18.5 W) MV (1.6 +/- 0.03 m.s(-1)), PV (2.0 +/- 0.03 m.s(-1)), and TW (199.1 +/- 7.2 J). For JS, session 3 PP (1,669.8 +/- 111.2 W) was significantly greater vs. sessions 1, 2, and 4 (1,601.2 +/- 58.4 W). Session 4 MP (1,403.2 +/- 88.6 W) and MV (1.9 +/- 0.1 m.s(-1)) for JS were significantly lower during sessions 1, 2, and 3 (MP: 1,479.4.5 +/- 44.8 W, MV: 2.0 +/- 0.05 m.s(-1)). TW (834.7 +/- 24.3 J) and PV (2.2 +/- 0.04 m.s(-1)) were statistically similar during all sessions for JS. The CVs ranged from 3.0 to 7.6% for the BT and 3.2 to 5.7% for the JS. ICCs for MP, PP, MV, PV, and TW were 0.92, 0.95, 0.94, 0.91, and 0.95, respectively, during BT. ICCs during JS for MP, PP, MV, PV, and TW were 0.96, 0.98, 0.94, 0.94, and 0.89, respectively. The results of the current study support the use of a 30 continuous and dynamic BT protocol as a reliable upper-body physical performance test, which can be administered with

  12. Risk Assessment of Shellfish Toxins

    Directory of Open Access Journals (Sweden)

    Rex Munday

    2013-11-01

    Full Text Available Complex secondary metabolites, some of which are highly toxic to mammals, are produced by many marine organisms. Some of these organisms are important food sources for marine animals and, when ingested, the toxins that they produce may be absorbed and stored in the tissues of the predators, which then become toxic to animals higher up the food chain. This is a particular problem with shellfish, and many cases of poisoning are reported in shellfish consumers each year. At present, there is no practicable means of preventing uptake of the toxins by shellfish or of removing them after harvesting. Assessment of the risk posed by such toxins is therefore required in order to determine levels that are unlikely to cause adverse effects in humans and to permit the establishment of regulatory limits in shellfish for human consumption. In the present review, the basic principles of risk assessment are described, and the progress made toward robust risk assessment of seafood toxins is discussed. While good progress has been made, it is clear that further toxicological studies are required before this goal is fully achieved.

  13. Uncertainties in risk assessment at USDOE facilities

    Energy Technology Data Exchange (ETDEWEB)

    Hamilton, L.D.; Holtzman, S.; Meinhold, A.F.; Morris, S.C.; Rowe, M.D.

    1994-01-01

    The United States Department of Energy (USDOE) has embarked on an ambitious program to remediate environmental contamination at its facilities. Decisions concerning cleanup goals, choices among cleanup technologies, and funding prioritization should be largely risk-based. Risk assessments will be used more extensively by the USDOE in the future. USDOE needs to develop and refine risk assessment methods and fund research to reduce major sources of uncertainty in risk assessments at USDOE facilities. The terms{open_quote} risk assessment{close_quote} and{open_quote} risk management{close_quote} are frequently confused. The National Research Council (1983) and the United States Environmental Protection Agency (USEPA, 1991a) described risk assessment as a scientific process that contributes to risk management. Risk assessment is the process of collecting, analyzing and integrating data and information to identify hazards, assess exposures and dose responses, and characterize risks. Risk characterization must include a clear presentation of {open_quotes}... the most significant data and uncertainties...{close_quotes} in an assessment. Significant data and uncertainties are {open_quotes}...those that define and explain the main risk conclusions{close_quotes}. Risk management integrates risk assessment information with other considerations, such as risk perceptions, socioeconomic and political factors, and statutes, to make and justify decisions. Risk assessments, as scientific processes, should be made independently of the other aspects of risk management (USEPA, 1991a), but current methods for assessing health risks are based on conservative regulatory principles, causing unnecessary public concern and misallocation of funds for remediation.

  14. Uncertainties in risk assessment at USDOE facilities

    International Nuclear Information System (INIS)

    Hamilton, L.D.; Holtzman, S.; Meinhold, A.F.; Morris, S.C.; Rowe, M.D.

    1994-01-01

    The United States Department of Energy (USDOE) has embarked on an ambitious program to remediate environmental contamination at its facilities. Decisions concerning cleanup goals, choices among cleanup technologies, and funding prioritization should be largely risk-based. Risk assessments will be used more extensively by the USDOE in the future. USDOE needs to develop and refine risk assessment methods and fund research to reduce major sources of uncertainty in risk assessments at USDOE facilities. The terms open-quote risk assessment close-quote and open-quote risk management close-quote are frequently confused. The National Research Council (1983) and the United States Environmental Protection Agency (USEPA, 1991a) described risk assessment as a scientific process that contributes to risk management. Risk assessment is the process of collecting, analyzing and integrating data and information to identify hazards, assess exposures and dose responses, and characterize risks. Risk characterization must include a clear presentation of open-quotes... the most significant data and uncertainties...close quotes in an assessment. Significant data and uncertainties are open-quotes...those that define and explain the main risk conclusionsclose quotes. Risk management integrates risk assessment information with other considerations, such as risk perceptions, socioeconomic and political factors, and statutes, to make and justify decisions. Risk assessments, as scientific processes, should be made independently of the other aspects of risk management (USEPA, 1991a), but current methods for assessing health risks are based on conservative regulatory principles, causing unnecessary public concern and misallocation of funds for remediation

  15. The reliability-quality relationship for quality systems and quality risk management.

    Science.gov (United States)

    Claycamp, H Gregg; Rahaman, Faiad; Urban, Jason M

    2012-01-01

    Engineering reliability typically refers to the probability that a system, or any of its components, will perform a required function for a stated period of time and under specified operating conditions. As such, reliability is inextricably linked with time-dependent quality concepts, such as maintaining a state of control and predicting the chances of losses from failures for quality risk management. Two popular current good manufacturing practice (cGMP) and quality risk management tools, failure mode and effects analysis (FMEA) and root cause analysis (RCA) are examples of engineering reliability evaluations that link reliability with quality and risk. Current concepts in pharmaceutical quality and quality management systems call for more predictive systems for maintaining quality; yet, the current pharmaceutical manufacturing literature and guidelines are curiously silent on engineering quality. This commentary discusses the meaning of engineering reliability while linking the concept to quality systems and quality risk management. The essay also discusses the difference between engineering reliability and statistical (assay) reliability. The assurance of quality in a pharmaceutical product is no longer measured only "after the fact" of manufacturing. Rather, concepts of quality systems and quality risk management call for designing quality assurance into all stages of the pharmaceutical product life cycle. Interestingly, most assays for quality are essentially static and inform product quality over the life cycle only by being repeated over time. Engineering process reliability is the fundamental concept that is meant to anticipate quality failures over the life cycle of the product. Reliability is a well-developed theory and practice for other types of manufactured products and manufacturing processes. Thus, it is well known to be an appropriate index of manufactured product quality. This essay discusses the meaning of reliability and its linkages with quality

  16. Network reliability assessment using a cellular automata approach

    International Nuclear Information System (INIS)

    Rocco S, Claudio M.; Moreno, Jose Ali

    2002-01-01

    Two cellular automata (CA) models that evaluate the s-t connectedness and shortest path in a network are presented. CA based algorithms enhance the performance of classical algorithms, since they allow a more reliable and straightforward parallel implementation resulting in a dynamic network evaluation, where changes in the connectivity and/or link costs can readily be incorporated avoiding recalculation from scratch. The paper also demonstrates how these algorithms can be applied for network reliability evaluation (based on Monte-Carlo approach) and for finding s-t path with maximal reliability

  17. Reliability and risk evaluation of a port oil pipeline transportation system in variable operation conditions

    International Nuclear Information System (INIS)

    Soszynska, Joanna

    2010-01-01

    The semi-Markov model of the system operation processes is proposed and its selected characteristics are determined. A system composed on multi-state components is considered and its reliability and risk characteristics are found. Next, the joint model of the system operation process and the system multi-state reliability is applied to the reliability and risk evaluation of the port oil pipeline transportation system. The pipeline system is described and its operation process unknown parameters are identified on the basis of real statistical data. The mean values of the pipeline system operation process unconditional sojourn times in particular operation states are found and applied to determining this process transient probabilities in these states. The piping different reliability structures in various its operation states are fixed and their conditional reliability functions on the basis of data coming from experts are approximately determined. Finally, after applying earlier estimated transient probabilities and system conditional reliability functions in particular operation states the unconditional reliability function, the mean values and standard deviations of the pipeline lifetimes in particular reliability states, risk function and the moment when the risk exceeds a critical value are found.

  18. Reliability and risk evaluation of a port oil pipeline transportation system in variable operation conditions

    Energy Technology Data Exchange (ETDEWEB)

    Soszynska, Joanna, E-mail: joannas@am.gdynia.p [Department of Mathematics, Gdynia Maritime University, ul. Morska 83, 81-225 Gdynia (Poland)

    2010-02-15

    The semi-Markov model of the system operation processes is proposed and its selected characteristics are determined. A system composed on multi-state components is considered and its reliability and risk characteristics are found. Next, the joint model of the system operation process and the system multi-state reliability is applied to the reliability and risk evaluation of the port oil pipeline transportation system. The pipeline system is described and its operation process unknown parameters are identified on the basis of real statistical data. The mean values of the pipeline system operation process unconditional sojourn times in particular operation states are found and applied to determining this process transient probabilities in these states. The piping different reliability structures in various its operation states are fixed and their conditional reliability functions on the basis of data coming from experts are approximately determined. Finally, after applying earlier estimated transient probabilities and system conditional reliability functions in particular operation states the unconditional reliability function, the mean values and standard deviations of the pipeline lifetimes in particular reliability states, risk function and the moment when the risk exceeds a critical value are found.

  19. The possibilities of applying a risk-oriented approach to the NPP reliability and safety enhancement problem

    Science.gov (United States)

    Komarov, Yu. A.

    2014-10-01

    An analysis and some generalizations of approaches to risk assessments are presented. Interconnection between different interpretations of the "risk" notion is shown, and the possibility of applying the fuzzy set theory to risk assessments is demonstrated. A generalized formulation of the risk assessment notion is proposed in applying risk-oriented approaches to the problem of enhancing reliability and safety in nuclear power engineering. The solution of problems using the developed risk-oriented approaches aimed at achieving more reliable and safe operation of NPPs is described. The results of studies aimed at determining the need (advisability) to modernize/replace NPP elements and systems are presented together with the results obtained from elaborating the methodical principles of introducing the repair concept based on the equipment technical state. The possibility of reducing the scope of tests and altering the NPP systems maintenance strategy is substantiated using the risk-oriented approach. A probabilistic model for estimating the validity of boric acid concentration measurements is developed.

  20. Exploring the interactions between forecast accuracy, risk perception and perceived forecast reliability in reservoir operator's decision to use forecast

    Science.gov (United States)

    Shafiee-Jood, M.; Cai, X.

    2017-12-01

    Advances in streamflow forecasts at different time scales offer a promise for proactive flood management and improved risk management. Despite the huge potential, previous studies have found that water resources managers are often not willing to incorporate streamflow forecasts information in decisions making, particularly in risky situations. While low accuracy of forecasts information is often cited as the main reason, some studies have found that implementation of streamflow forecasts sometimes is impeded by institutional obstacles and behavioral factors (e.g., risk perception). In fact, a seminal study by O'Connor et al. (2005) found that risk perception is the strongest determinant of forecast use while managers' perception about forecast reliability is not significant. In this study, we aim to address this issue again. However, instead of using survey data and regression analysis, we develop a theoretical framework to assess the user-perceived value of streamflow forecasts. The framework includes a novel behavioral component which incorporates both risk perception and perceived forecast reliability. The framework is then used in a hypothetical problem where reservoir operator should react to probabilistic flood forecasts with different reliabilities. The framework will allow us to explore the interactions among risk perception and perceived forecast reliability, and among the behavioral components and information accuracy. The findings will provide insights to improve the usability of flood forecasts information through better communication and education.

  1. Total cardiovascular disease risk assessment: a review.

    LENUS (Irish Health Repository)

    Cooney, Marie Therese

    2011-09-01

    The high risk strategy for the prevention of cardiovascular disease (CVD) requires an assessment of an individual\\'s total CVD risk so that the most intensive risk factor management can be directed towards those at highest risk. Here we review developments in the assessment and estimation of total CVD risk.

  2. Systems Analysis Programs for Hands-on Integrated Reliability Evaluations (SAPHIRE), Version 5.0: Integrated Reliability and Risk Analysis System (IRRAS) reference manual. Volume 2

    International Nuclear Information System (INIS)

    Russell, K.D.; Kvarfordt, K.J.; Skinner, N.L.; Wood, S.T.; Rasmuson, D.M.

    1994-07-01

    The Systems Analysis Programs for Hands-on Integrated Reliability Evaluations (SAPHIRE) refers to a set of several microcomputer programs that were developed to create and analyze probabilistic risk assessments (PRAs), primarily for nuclear power plants. 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 use 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 to report generation. Version 1.0 of the IRRAS program was released in February of 1987. Since then, 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 5.0 and is the subject of this Reference Manual. Version 5.0 of IRRAS provides the same capabilities as earlier versions and ads the ability to perform location transformations, seismic analysis, and provides enhancements to the user interface as well as improved algorithm performance. Additionally, version 5.0 contains new alphanumeric fault tree and event used for event tree rules, recovery rules, and end state partitioning

  3. Structural Reliability Methods for Wind Power Converter System Component Reliability Assessment

    DEFF Research Database (Denmark)

    Kostandyan, Erik; Sørensen, John Dalsgaard

    2012-01-01

    Wind power converter systems are essential subsystems in both off-shore and on-shore wind turbines. It is the main interface between generator and grid connection. This system is affected by numerous stresses where the main contributors might be defined as vibration and temperature loadings....... The temperature variations induce time-varying stresses and thereby fatigue loads. A probabilistic model is used to model fatigue failure for an electrical component in the power converter system. This model is based on a linear damage accumulation and physics of failure approaches, where a failure criterion...... is defined by the threshold model. The attention is focused on crack propagation in solder joints of electrical components due to the temperature loadings. Structural Reliability approaches are used to incorporate model, physical and statistical uncertainties. Reliability estimation by means of structural...

  4. 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...

  5. [Risk Assessment and Risk Management of Chemicals in China].

    Science.gov (United States)

    Wang, Tie-yu; Zhou, Yun-qiao; Li, Qi-feng; Lü, Yong-long

    2016-02-15

    Risk assessment and risk management have been increasingly approved as an effective approach for appropriate disposal and scientific management of chemicals. This study systematically analyzed the risk assessment methods of chemicals from three aspects including health risk, ecological risk and regional risk. Based on the current situation of classification and management towards chemicals in China, a specific framework of risk management on chemicals was proposed by selecting target chemicals, predominant industries and related stakeholders as the objects. The results of the present study will provide scientific support for improving risk assessment and reasonable management of chemicals in China.

  6. Risk communication and environmental risk assessment

    International Nuclear Information System (INIS)

    Petts, J.

    1994-01-01

    This paper attempts to provide a broad context for consideration of appropriate risk communication approaches. It examines the basis of public concerns and in particular the non-risk dimensions. The latter are so important in any risk decision that means of communication which can deal with them are required which extend beyond understanding how to present risk estimates. These means relate to (a) the decision processes themselves and the extent to which they provide for involvement of the public in decisions, (b) the communication skills of experts, and (c) the robustness of the risk information which is available. (Author)

  7. Optimal Bi-Objective Redundancy Allocation for Systems Reliability and Risk Management

    DEFF Research Database (Denmark)

    Govindan, Kannan; Jafarian, Ahmad; Azbari, Mostafa E.

    2016-01-01

    In the big data era, systems reliability is critical to effective systems risk management. In this paper, a novel multiobjective approach, with hybridization of a known algorithm called NSGA-II and an adaptive population-based simulated annealing (APBSA) method is developed to solve the systems...... of domination; and 4) data envelopment analysis. The computational studies have shown that the proposed algorithm is an effective approach for systems reliability and risk management....

  8. Molecular radiobiology and risk assessment

    International Nuclear Information System (INIS)

    Georgieva, R.

    2009-01-01

    Full text: Attitudes towards the radiation protection standards on in Europe and the world largely depends on scientific knowledge, periodically published by the United Nations Scientific Committee (UNSCEAR) and the recommendations of the International Commission on Radiation Protection (ICRP), which also comply with the research. The new scientific evidence by conducting an additional research is a crucial element in the process of protection of people, workers and patients in medicine from the adverse health effects. Although these standards are clear and easy to apply, there is serious doubt from a scientific perspective about the level of health risk at low doses, which keep up a fierce debate, both eight scientific and political society. The answer to this question requires the integrated efforts of many scientific disciplines. Increasingly rapid advances in biological and medical knowledge provide the necessary conditions for achieving this aim. This lecture tries to shed light on the current state of knowledge, the main unresolved problems in science in the context of radiation protection and risk assessment, and on those lines of research that have the greatest potential to address the issues. They mainly concern issues of doses and biological effects of different types of ionisation radiation, biological effects in cells/tissues which initiate health effects at low doses, individual variability and direct health risk assessment by epidemiological studies of groups exposed to lower doses irradiation

  9. Risk and Reliability of Infrastructure Asset Management Workshop

    National Research Council Canada - National Science Library

    2006-01-01

    A workshop was held August 15-18 in Alexandria, Virginia to begin the dialog on the methodologies available and the status of how the US Army Corps of Engineers assesses its Civil Works infrastructure...

  10. Assessment and Improving Methods of Reliability Indices in Bakhtar Regional Electricity Company

    Directory of Open Access Journals (Sweden)

    Saeed Shahrezaei

    2013-04-01

    Full Text Available Reliability of a system is the ability of a system to do prospected duties in future and the probability of desirable operation for doing predetermined duties. Power system elements failures data are the main data of reliability assessment in the network. Determining antiseptic parameters is the goal of reliability assessment by using system history data. These parameters help to recognize week points of the system. In other words, the goal of reliability assessment is operation improving and decreasing of the failures and power outages. This paper is developed to assess reliability indices of Bakhtar Regional Electricity Company up to 1393 and the improving methods and their effects on the reliability indices in this network. DIgSILENT Power Factory software is employed for simulation. Simulation results show the positive effect of improving methods in reliability indices of Bakhtar Regional Electricity Company.

  11. Psychometrics of the Iowa and Berlin Gambling Tasks: Unresolved Issues With Reliability and Validity for Risk Taking.

    Science.gov (United States)

    Schmitz, Florian; Kunina-Habenicht, Olga; Hildebrandt, Andrea; Oberauer, Klaus; Wilhelm, Oliver

    2018-01-01

    The Iowa Gambling Task (IGT) is one of the most prominent paradigms employed for the assessment of risk taking in the laboratory, and it was shown to distinguish between various patient groups and controls. The present study was conducted to test the psychometric characteristics of the original IGT and of a new gambling task variant for assessing individual differences. Two studies were conducted with adults of the general population ( n = 220) and with adolescents ( n = 389). Participants were also tested on multiple measures of working memory capacity, fluid intelligence, personality traits associated with risk-taking behavior, and self-reported risk taking in various domains. Both gambling tasks had only moderate retest reliability within the same session. Moderate relations were obtained with cognitive ability. However, card selections in the gambling tasks were not correlated with personality or risk taking. These findings point to limitations of IGT type gambling tasks for the assessment of individual differences in risky decision making.

  12. Risk assessment for construction projects of transport infrastructure objects

    Science.gov (United States)

    Titarenko, Boris

    2017-10-01

    The paper analyzes and compares different methods of risk assessment for construction projects of transport objects. The management of such type of projects demands application of special probabilistic methods due to large level of uncertainty of their implementation. Risk management in the projects requires the use of probabilistic and statistical methods. The aim of the work is to develop a methodology for using traditional methods in combination with robust methods that allow obtaining reliable risk assessments in projects. The robust approach is based on the principle of maximum likelihood and in assessing the risk allows the researcher to obtain reliable results in situations of great uncertainty. The application of robust procedures allows to carry out a quantitative assessment of the main risk indicators of projects when solving the tasks of managing innovation-investment projects. Calculation of damage from the onset of a risky event is possible by any competent specialist. And an assessment of the probability of occurrence of a risky event requires the involvement of special probabilistic methods based on the proposed robust approaches. Practice shows the effectiveness and reliability of results. The methodology developed in the article can be used to create information technologies and their application in automated control systems for complex projects.

  13. Reliability assessment of Port Harcourt 33/11kv Distribution System ...

    African Journals Online (AJOL)

    This makes reliability studies an important task besides all the other analyses required for assessing the system performance. The paper presents an analytical approach in the reliability assessment of the Port Harcourt 33/11kV power distribution system. The assessment was performed with the 2009 power outage data ...

  14. Assessment of landslide distribution map reliability in Niigata prefecture - Japan using frequency ratio approach

    Science.gov (United States)

    Rahardianto, Trias; Saputra, Aditya; Gomez, Christopher

    2017-07-01

    Research on landslide susceptibility has evolved rapidly over the few last decades thanks to the availability of large databases. Landslide research used to be focused on discreet events but the usage of large inventory dataset has become a central pillar of landslide susceptibility, hazard, and risk assessment. Indeed, extracting meaningful information from the large database is now at the forth of geoscientific research, following the big-data research trend. Indeed, the more comprehensive information of the past landslide available in a particular area is, the better the produced map will be, in order to support the effective decision making, planning, and engineering practice. The landslide inventory data which is freely accessible online gives an opportunity for many researchers and decision makers to prevent casualties and economic loss caused by future landslides. This data is advantageous especially for areas with poor landslide historical data. Since the construction criteria of landslide inventory map and its quality evaluation remain poorly defined, the assessment of open source landslide inventory map reliability is required. The present contribution aims to assess the reliability of open-source landslide inventory data based on the particular topographical setting of the observed area in Niigata prefecture, Japan. Geographic Information System (GIS) platform and statistical approach are applied to analyze the data. Frequency ratio method is utilized to model and assess the landslide map. The outcomes of the generated model showed unsatisfactory results with AUC value of 0.603 indicate the low prediction accuracy and unreliability of the model.

  15. Current issues and perspectives in food safety and risk assessment.

    Science.gov (United States)

    Eisenbrand, G

    2015-12-01

    In this review, current issues and opportunities in food safety assessment are discussed. Food safety is considered an essential element inherent in global food security. Hazard characterization is pivotal within the continuum of risk assessment, but it may be conceived only within a very limited frame as a true alternative to risk assessment. Elucidation of the mode of action underlying a given hazard is vital to create a plausible basis for human toxicology evaluation. Risk assessment, to convey meaningful risk communication, must be based on appropriate and reliable consideration of both exposure and mode of action. New perspectives, provided by monitoring human exogenous and endogenous exposure biomarkers, are considered of great promise to support classical risk extrapolation from animal toxicology. © The Author(s) 2015.

  16. Commercial Off-The-Shelf (COTS) Parts Risk and Reliability User and Application Guide

    Science.gov (United States)

    White, Mark

    2017-01-01

    All COTS parts are not created equal. Because they are not created equal, the notion that one can force the commercial industry to follow a set of military specifications and standards, along with the certifications, audits and qualification commitments that go with them, is unrealistic for the sale of a few parts. The part technologies that are Defense Logistics Agency (DLA) certified or Military Specification (MS) qualified, are several generations behind the state-of-the-art high-performance parts that are required for the compact, higher performing systems for the next generation of spacecraft and instruments. The majority of the part suppliers are focused on the portion of the market that is producing high-tech commercial products and systems. To that end, in order to compete in the high performance and leading edge advanced technological systems, an alternative approach to risk assessment and reliability prediction must be considered.

  17. The effect of introducing increased-reliability-risk electronic components into 3rd generation telecommunications systems

    International Nuclear Information System (INIS)

    Salmela, Olli

    2005-01-01

    In this paper, the dependability of 3rd generation telecommunications network systems is studied. Special attention is paid to a case where increased-reliability-risk electronic components are introduced to the system. The paper consists of three parts: First, the reliability data of four electronic components is considered. This includes statistical analysis of the reliability test data, thermo-mechanical finite element analysis of the printed wiring board structures, and based on those, a field reliability estimate of the components is constructed. Second, the component level reliability data is introduced into the network element reliability analysis. This is accomplished by using a reliability block diagram technique and Monte Carlo simulation of the network element. The end result of the second part is a reliability estimate of the network element with and without the high-risk component. Third, the whole 3rd generation network having multiple network elements is analyzed. In this part, the criticality of introducing high-risk electronic components into a 3rd generation telecommunications network is considered

  18. The effect of introducing increased-reliability-risk electronic components into 3rd generation telecommunications systems

    Energy Technology Data Exchange (ETDEWEB)

    Salmela, Olli [Nokia Networks, P.O. Box 301, 00045 Nokia Group (Finland)]. E-mail: olli.salmela@nokia.com

    2005-08-01

    In this paper, the dependability of 3rd generation telecommunications network systems is studied. Special attention is paid to a case where increased-reliability-risk electronic components are introduced to the system. The paper consists of three parts: First, the reliability data of four electronic components is considered. This includes statistical analysis of the reliability test data, thermo-mechanical finite element analysis of the printed wiring board structures, and based on those, a field reliability estimate of the components is constructed. Second, the component level reliability data is introduced into the network element reliability analysis. This is accomplished by using a reliability block diagram technique and Monte Carlo simulation of the network element. The end result of the second part is a reliability estimate of the network element with and without the high-risk component. Third, the whole 3rd generation network having multiple network elements is analyzed. In this part, the criticality of introducing high-risk electronic components into a 3rd generation telecommunications network is considered.

  19. Information Security Risk Assessment in Hospitals.

    Science.gov (United States)

    Ayatollahi, Haleh; Shagerdi, Ghazal

    2017-01-01

    To date, many efforts have been made to classify information security threats, especially in the healthcare area. However, there are still many unknown risks which may threat the security of health information and their resources especially in the hospitals. The aim of this study was to assess the risks threatening information security in the hospitals located in one of the northwest cities of Iran. This study was completed in 2014. The participants were information technology managers who worked in the hospitals (n=27). The research instrument was a questionnaire composed of a number of open and closed questions. The content validity of the questionnaire was confirmed, and the reliability of the closed questions was measured by using the test-retest method (r =0.78). The results showed that among the information security risks, fire found to be a high probability/high impact risk factor. Human and physical/environmental threats were among the low probability risk factors. Regarding the information security safeguards used in the hospitals, the results showed that the use of the technical safeguards was the most frequent one (n =22, 91.7%) compared to the administrative (n =21, 87.5%) and the physical safeguards (n =16, 66.7%). The high probability risk factors require quick corrective actions to be taken. Therefore, the underlying causes of such threats should be identified and controlled before experiencing adverse effects. It is also important to note that information security in health care systems needs to be considered at a macro level with respect to the national interests and policies.

  20. Reliability of the Bulb Dynamometer for Assessing Grip Strength

    Directory of Open Access Journals (Sweden)

    Colleen Maher

    2018-04-01

    Full Text Available Background: Hand function is an overall indicator of health and is often measured using grip strength. Handheld dynamometry is the most common method of measuring grip strength. The purpose of this study was to determine the inter-rater and test-retest reliability, the reliability of one trial versus three trials, and the preliminary norms for a young adult population using the Baseline® Pneumatic Squeeze Bulb Dynamometer (30 psi. Methods: This study used a one-group methodological design. One hundred and three healthy adults (30 males and 73 females were recruited. Six measurements were collected for each hand per participant. The data was analyzed using Intraclass Correlation Coefficients (ICC two-way effects model (2,2 and paired-samples t-tests. Results: The ICC for inter-rater reliability ranged from 0.955 to 0.977. Conclusion: The results of this study suggest that the bulb dynamometer is a reliable tool to measure grip strength and should be further explored for reliable and valid use in diverse populations and as an alternative to the Jamar dynamometer.

  1. Concept of risk: risk assessment and nuclear safety

    International Nuclear Information System (INIS)

    Thompson, P.B.

    1980-01-01

    The dissertation is a critical examination of risk assessment and its role in public policy. Nuclear power safety safety issues are selected as the primary source of illustrations and examples. The dissertation examines how risk assessment studies develop a concept of risk which becomes decisive for policy choices. Risk-assessment techniques are interpreted as instruments which secure an evaluation of risk which, in turn, figures prominently in technical reports on nuclear power. The philosophical critique is mounted on two levels. First, an epistemological critique surveys distinctions between the technical concept of risk and more familiar senses of risk. The critique shows that utilization of risk assessment re-structures the concept of risk. The technical concept is contrasted to the function of risk within a decision-maker's conceptual agenda and hierarchy of values. Second, an ethical critique exposes the value commitments of risk assessment recommendations. Although some of these values might be defended for policy decisions, the technical character of risk assessment obfuscates normative issues. Risk assessment is shown to be a form of factual enquiry which, nonetheless, represents a commitment to a specific selection of ethical and social values. Risk assessment should not be interpreted as a primary guide to decision unless the specific values incorporated into its concept of risk are stated explicitly and justified philosophically. Such a statement would allow value questions which have been sublimated by the factual tone of the analytic techniques to be debated on clear, social and ethical grounds

  2. Validity and reliability of self-reported diabetes in the Atherosclerosis Risk in Communities Study.

    Science.gov (United States)

    Schneider, Andrea L C; Pankow, James S; Heiss, Gerardo; Selvin, Elizabeth

    2012-10-15

    The objective of this study was to assess the validity of prevalent and incident self-reported diabetes compared with multiple reference definitions and to assess the reliability (repeatability) of a self-reported diagnosis of diabetes. Data from 10,321 participants in the Atherosclerosis Risk in Communities (ARIC) Study who attended visit 4 (1996-1998) were analyzed. Prevalent self-reported diabetes was compared with reference definitions defined by fasting glucose and medication use obtained at visit 4. Incident self-reported diabetes was assessed during annual follow-up telephone calls and was compared with reference definitions defined by fasting glucose, hemoglobin A1c, and medication use obtained during an in-person visit attended by a subsample of participants (n = 1,738) in 2004-2005. The sensitivity of prevalent self-reported diabetes ranged from 58.5% to 70.8%, and specificity ranged from 95.6% to 96.8%, depending on the reference definition. Similarly, the sensitivity of incident self-reported diabetes ranged from 55.9% to 80.4%, and specificity ranged from 84.5% to 90.6%. Percent positive agreement of self-reported diabetes during 9 years of repeat assessments ranged from 92.7% to 95.4%. Both prevalent self-reported diabetes and incident self-reported diabetes were 84%-97% specific and 55%-80% sensitive as compared with reference definitions using glucose and medication criteria. Self-reported diabetes was >92% reliable over time.

  3. Nuclear computerized library for assessing reactor reliability (NUCLARR): Data manual: Part 1, Summary description

    International Nuclear Information System (INIS)

    Gertman, D.I.; Gilbert, B.G.; Gilmore, W.E.; Galyean, W.J.

    1988-06-01

    This volume of a five-volume series summarizes those data currently resident in the first release of the Nuclear Computerized Library for Assessing Reactor Reliability (NUCLARR) data base. The raw human error probability (HEP) and hardware component failure data (HCFD) contained herein are accompanied by a glossary of terms and the HEP and hardware taxonomies used to structure the data. Instructions are presented on how the user may navigate through the NUCLARR data management system to find anchor values to assist in solving risk-related problems. Volume V: Data Manual will be updated on a periodic basis so that risk analysis without access to a computer may have access to the largest NUCLARR data. This document Part 1 of Volume 5 introduces aspects of the NUCLARR data base management system and prepares the reader for reviewing data in other Parts of Volume 5

  4. Risk assessment of nickel carcinogenicity and occupational lung cancer.

    OpenAIRE

    Shen, H M; Zhang, Q F

    1994-01-01

    Recent progress in risk assessment of nickel carcinogenicity and its correlation with occupational lung cancer in nickel-exposed workers is reviewed. Epidemiological investigations provide reliable data indicating the close relation between nickel exposure and high lung cancer risk, especially in nickel refineries. The nickel species-specific effects and the dose-response relationship between nickel exposure and lung cancer are among the main questions that are explored extensively. It is als...

  5. Risk assessment terminology: risk communication part 1

    Directory of Open Access Journals (Sweden)

    Gaetano Liuzzo

    2016-03-01

    Full Text Available The paper describes the terminology of risk communication in the view of food safety: the theory of stakeholders, the citizens’ involvement and the community interest and consultation are reported. Different aspects of risk communication (public communication, scientific uncertainty, trust, care, consensus and crisis communication are discussed.

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

    Science.gov (United States)

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

    2014-08-01

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

  7. Earthquake risk assessment of building structures

    International Nuclear Information System (INIS)

    Ellingwood, Bruce R.

    2001-01-01

    During the past two decades, probabilistic risk analysis tools have been applied to assess the performance of new and existing building structural systems. Structural design and evaluation of buildings and other facilities with regard to their ability to withstand the effects of earthquakes requires special considerations that are not normally a part of such evaluations for other occupancy, service and environmental loads. This paper reviews some of these special considerations, specifically as they pertain to probability-based codified design and reliability-based condition assessment of existing buildings. Difficulties experienced in implementing probability-based limit states design criteria for earthquake are summarized. Comparisons of predicted and observed building damage highlight the limitations of using current deterministic approaches for post-earthquake building condition assessment. The importance of inherent randomness and modeling uncertainty in forecasting building performance is examined through a building fragility assessment of a steel frame with welded connections that was damaged during the Northridge Earthquake of 1994. The prospects for future improvements in earthquake-resistant design procedures based on a more rational probability-based treatment of uncertainty are examined

  8. A clinical assessment tool used for physiotherapy students--is it reliable?

    Science.gov (United States)

    Lewis, Lucy K; Stiller, Kathy; Hardy, Frances

    2008-01-01

    Educational institutions providing professional programs such as physiotherapy must provide high-quality student assessment procedures. To ensure that assessment is consistent, assessment tools should have an acceptable level of reliability. There is a paucity of research evaluating the reliability of clinical assessment tools used for physiotherapy students. This study evaluated the inter- and intrarater reliability of an assessment tool used for physiotherapy students during a clinical placement. Five clinical educators and one academic participated in the study. Each rater independently marked 22 student written assessments that had been completed by students after viewing a videotaped patient physiotherapy assessment. The raters repeated the marking process 7 weeks later, with the assessments provided in a randomised order. The interrater reliability (Intraclass Correlation Coefficient) for the total scores was 0.32, representing a poor level of reliability. A high level of intrarater reliability (percentage agreement) was found for the clinical educators, with a difference in section scores of one mark or less on 93.4% of occasions. Further research should be undertaken to reevaluate the reliability of this clinical assessment tool following training. The reliability of clinical assessment tools used in other areas of physiotherapy education should be formally measured rather than assumed.

  9. RISK MANAGEMENT: AN INTEGRATED APPROACH TO RISK MANAGEMENT AND ASSESSMENT

    Directory of Open Access Journals (Sweden)

    Szabo Alina

    2012-12-01

    Full Text Available Purpose: The objective of this paper is to offer an overview over risk management cycle by focusing on prioritization and treatment, in order to ensure an integrated approach to risk management and assessment, and establish the ‘top 8-12’ risks report within the organization. The interface with Internal Audit is ensured by the implementation of the scoring method to prioritize risks collected from previous generated risk report. Methodology/approach: Using evidence from other research in the area and the professional expertise, this article outlines an integrated approach to risk assessment and risk management reporting processes, by separating the risk in two main categories: strategic and operational risks. The focus is on risk prioritization and scoring; the final output will comprise a mix of strategic and operational (‘top 8-12’ risks, which should be used to establish the annual Internal Audit plan. Originality/value: By using an integrated approach to risk assessment and risk management will eliminate the need for a separate Internal Audit risk assessment over prevailing risks. It will reduce the level of risk assessment overlap by different functions (Tax, Treasury, Information System over the same risk categories as a single methodology, is used and will align timings of risk assessment exercises. The risk prioritization by usage of risk and control scoring criteria highlights the combination between financial and non-financial impact criteria allowing risks that do not naturally lend themselves to a financial amount to be also assessed consistently. It is emphasized the usage of score method to prioritize the risks included in the annual audit plan in order to increase accuracy and timelines.

  10. Risks, risk assessment and risk competence in toxicology

    Science.gov (United States)

    Stahlmann, Ralf; Horvath, Aniko

    2015-01-01

    Understanding the toxic effects of xenobiotics requires sound knowledge of physiology and biochemistry. The often described lack of understanding pharmacology/toxicology is therefore primarily caused by the general absence of the necessary fundamental knowledge. Since toxic effects depend on exposure (or dosage) assessing the risks arising from toxic substances also requires quantitative reasoning. Typically public discussions nearly always neglect quantitative aspects and laypersons tend to disregard dose-effect-relationships. One of the main reasons for such disregard is the fact that exposures often occur at extremely low concentrations that can only be perceived intellectually but not by the human senses. However, thresholds in the low exposure range are often scientifically disputed. At the same time, ignorance towards known dangers is wide-spread. Thus, enhancing the risk competence of laypersons will have to be initially restricted to increasing the awareness of existing problems. PMID:26195922

  11. Risks, risk assessment and risk competence in toxicology.

    Science.gov (United States)

    Stahlmann, Ralf; Horvath, Aniko

    2015-01-01

    Understanding the toxic effects of xenobiotics requires sound knowledge of physiology and biochemistry. The often described lack of understanding pharmacology/toxicology is therefore primarily caused by the general absence of the necessary fundamental knowledge. Since toxic effects depend on exposure (or dosage) assessing the risks arising from toxic substances also requires quantitative reasoning. Typically public discussions nearly always neglect quantitative aspects and laypersons tend to disregard dose-effect-relationships. One of the main reasons for such disregard is the fact that exposures often occur at extremely low concentrations that can only be perceived intellectually but not by the human senses. However, thresholds in the low exposure range are often scientifically disputed. At the same time, ignorance towards known dangers is wide-spread. Thus, enhancing the risk competence of laypersons will have to be initially restricted to increasing the awareness of existing problems.

  12. Risks, risk assessment and risk competence in toxicology

    Directory of Open Access Journals (Sweden)

    Stahlmann, Ralf

    2015-07-01

    Full Text Available Understanding the toxic effects of xenobiotics requires sound knowledge of physiology and biochemistry. The often described lack of understanding pharmacology/toxicology is therefore primarily caused by the general absence of the necessary fundamental knowledge. Since toxic effects depend on exposure (or dosage assessing the risks arising from toxic substances also requires quantitative reasoning. Typically public discussions nearly always neglect quantitative aspects and laypersons tend to disregard dose-effect-relationships. One of the main reasons for such disregard is the fact that exposures often occur at extremely low concentrations that can only be perceived intellectually but not by the human senses. However, thresholds in the low exposure range are often scientifically disputed. At the same time, ignorance towards known dangers is wide-spread. Thus, enhancing the risk competence of laypersons will have to be initially restricted to increasing the awareness of existing problems.

  13. Component reliability data for use in probabilistic safety assessment

    International Nuclear Information System (INIS)

    1988-10-01

    Generic component reliability data is indispensable in any probabilistic safety analysis. It is not realistic to assume that all possible component failures and failure modes modeled in a PSA would be available from the operating experience of a specific plant in a statistically meaningful way. The degree that generic data is used in PSAs varies from case to case. Some studies are totally based on generic data while others use generic data as prior information to be specialized by plant specific data. Most studies, however, finally use a combination where data for certain components come from generic data sources and others from Bayesian updating. The IAEA effort to compile a generic component reliability data base aimed at facilitating the use of data available in the literature and at highlighting pitfalls which deserve special consideration. It was also intended to complement the fault tree and event tree package (PSAPACK) and to facilitate its use. Moreover, it should be noted, that the IAEA has recently initiated a Coordinated Research Program in Reliability Data Collection, Retrieval and Analysis. In this framework the issues identified as most affecting the quality of existing data bases would be addressed. This report presents the results of a compilation made from the specialized literature and includes reliability data for components usually considered in PSA

  14. Training Raters to Assess Adult ADHD: Reliability of Ratings

    Science.gov (United States)

    Adler, Lenard A.; Spencer, Thomas; Faraone, Stephen V.; Reimherr, Fred W.; Kelsey, Douglas; Michelson, David; Biederman, Joseph

    2005-01-01

    The standardization of ADHD ratings in adults is important given their differing symptom presentation. The authors investigated the agreement and reliability of rater standardization in a large-scale trial of atomoxetine in adults with ADHD. Training of 91 raters for the investigator-administered ADHD Rating Scale (ADHDRS-IV-Inv) occurred prior to…

  15. Re-assessing reliability based on survived loads

    NARCIS (Netherlands)

    Schweckendiek, T.

    2011-01-01

    The reliability of flood defenses is often dictated by large uncertainties in the hydraulic loading and the structural resistance. Additional information decreases uncertainty, however, acquiring it is often costly. One source of information, even though in many cases readily available, is hardly

  16. Assessing Assertion: An Investigation of Construct Validity and Reliability.

    Science.gov (United States)

    Kern, Jeffrey M.; MacDonald, Marian L.

    The reliability and meaning of assertiveness tests were explored using 120 female undergraduates. Several self-report inventories (the College Self-Expression Scale, Conflict Resolution Inventory, and a global rating from one to seven) were administered, as were three anxiety measures (Timed Behavior Checklist, response latency, and response…

  17. Pattern Recognition for Reliability Assessment of Water Distribution Networks

    NARCIS (Netherlands)

    Trifunovi?, N.

    2012-01-01

    The study presented in this manuscript investigates the patterns that describe reliability of water distribution networks focusing to the node connectivity, energy balance, and economics of construction, operation and maintenance. A number of measures to evaluate the network resilience has been

  18. Assessment of the Reliability Profiles for Concrete Bridges

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    In this paper calculation of reliability profiles is discussed. ULS as well as SLS limit states are formulated. Corrosion due to chloride penetration is the considered deterioration mechanism. Three models for corrosion are formulated. A definition of service lifetime for concrete bridges...

  19. Technical report on reliability assessment of the digital I and C equipment using reliability block diagram

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Dong Young; Hwang, In Koo; Cha, Kyung Ho; Park, Joo Hyun; Choi, Jong Gyun; Lee, Ki Young; Park, Jong Kyun [Korea Atomic Energy Research Institute, Taejeon (Korea)

    2002-03-01

    As the operational life-time of nuclear power plants being currently developed is increasing with technology improvements, the life-time of instrumentation and control systems is also required to be met to this plant operational period. The electronic devices are usually expected to be available less than for 10 years. Therefore, an appropriate S and PM (surveillance and preventive maintenance) strategy should be established to secure the reliability and availability of the plants. EPRI-URD requires that the mean time between failures caused by any I and C system failure shall be more than 50 operating years. The methodology to access of the mean time between failures of I and C system is included in this report. 35 refs., 19 figs., 3 tabs. (Author)

  20. A framework for combining social impact assessment and risk assessment

    NARCIS (Netherlands)

    Mahmoudi, Hossein; Renn, Ortwin; Vanclay, Frank; Hoffmann, Volker; Karami, Ezatollah

    An increasing focus on integrative approaches is one of the current trends in impact assessment. There is potential to combine impact assessment with various other forms of assessment, such as risk assessment, to make impact assessment and the management of social risks more effective. We identify