Reliability and Maintainability Analysis of a High Air Pressure Compressor Facility

Science.gov (United States)

Safie, Fayssal M.; Ring, Robert W.; Cole, Stuart K.

2013-01-01

This paper discusses a Reliability, Availability, and Maintainability (RAM) independent assessment conducted to support the refurbishment of the Compressor Station at the NASA Langley Research Center (LaRC). The paper discusses the methodologies used by the assessment team to derive the repair by replacement (RR) strategies to improve the reliability and availability of the Compressor Station (Ref.1). This includes a RAPTOR simulation model that was used to generate the statistical data analysis needed to derive a 15-year investment plan to support the refurbishment of the facility. To summarize, study results clearly indicate that the air compressors are well past their design life. The major failures of Compressors indicate that significant latent failure causes are present. Given the occurrence of these high-cost failures following compressor overhauls, future major failures should be anticipated if compressors are not replaced. Given the results from the RR analysis, the study team recommended a compressor replacement strategy. Based on the data analysis, the RR strategy will lead to sustainable operations through significant improvements in reliability, availability, and the probability of meeting the air demand with acceptable investment cost that should translate, in the long run, into major cost savings. For example, the probability of meeting air demand improved from 79.7 percent for the Base Case to 97.3 percent. Expressed in terms of a reduction in the probability of failing to meet demand (1 in 5 days to 1 in 37 days), the improvement is about 700 percent. Similarly, compressor replacement improved the operational availability of the facility from 97.5 percent to 99.8 percent. Expressed in terms of a reduction in system unavailability (1 in 40 to 1 in 500), the improvement is better than 1000 percent (an order of magnitude improvement). It is worthy to note that the methodologies, tools, and techniques used in the LaRC study can be used to evaluate

Reliability and Maintainability (RAM) Training

Science.gov (United States)

Lalli, Vincent R. (Editor); Malec, Henry A. (Editor); Packard, Michael H. (Editor)

2000-01-01

The theme of this manual is failure physics-the study of how products, hardware, software, and systems fail and what can be done about it. The intent is to impart useful information, to extend the limits of production capability, and to assist in achieving low-cost reliable products. In a broader sense the manual should do more. It should underscore the urgent need CI for mature attitudes toward reliability. Five of the chapters were originally presented as a classroom course to over 1000 Martin Marietta engineers and technicians. Another four chapters and three appendixes have been added, We begin with a view of reliability from the years 1940 to 2000. Chapter 2 starts the training material with a review of mathematics and a description of what elements contribute to product failures. The remaining chapters elucidate basic reliability theory and the disciplines that allow us to control and eliminate failures.

ETARA PC version 3.3 user's guide: Reliability, availability, maintainability simulation model

Science.gov (United States)

Hoffman, David J.; Viterna, Larry A.

1991-01-01

A user's manual describing an interactive, menu-driven, personal computer based Monte Carlo reliability, availability, and maintainability simulation program called event time availability reliability (ETARA) is discussed. Given a reliability block diagram representation of a system, ETARA simulates the behavior of the system over a specified period of time using Monte Carlo methods to generate block failure and repair intervals as a function of exponential and/or Weibull distributions. Availability parameters such as equivalent availability, state availability (percentage of time as a particular output state capability), continuous state duration and number of state occurrences can be calculated. Initial spares allotment and spares replenishment on a resupply cycle can be simulated. The number of block failures are tabulated both individually and by block type, as well as total downtime, repair time, and time waiting for spares. Also, maintenance man-hours per year and system reliability, with or without repair, at or above a particular output capability can be calculated over a cumulative period of time or at specific points in time.

Increasing the reliability, availability, and maintainability of the AP600 by design

International Nuclear Information System (INIS)

Trombola, D.; Meyer, C.

1993-01-01

The AP600 design is based on providing a safe, simple, standardized, and economically competitive design with a high degree of operability and ease of maintenance. Design features such as component selection, layout, and standardization increase the probability that targeted repair times are achieved. Design requirements from the utility industry and industry design practices have established criteria for: layout, changeout and replacement of parts and components; access for major pieces of equipment; and vehicle passage. These features coupled with a solid reliability assurance and maintenance program will help the AP600 meet its objectives for operation and maintenance. The AP600 draws on the operating experience and lessons learned from the utility community through design workshops and design review interaction, as well as operating plant data from sources several sources. Internally, the AP600 program incorporates the resources of Westinghouse NSD (Nuclear Service Division), which for decades has provided refueling, steam generator, reactor coolant pump, and other operating plant services. Since the early phases of the design process, the AP600 Program has executed a comprehensive reliability, availability, and maintainability program (RAM) which dealt primarily with assessing and improving plant availability. In conjunction with this program a Probabilistic Risk Assessment (PRA) was performed and submitted to the NRC with the Standard Safety Analysis Report (SSAR) in June 1992. This paper describes how AP600 ensures that the plant has design features to enhance reliability, availability, and maintainability. The RAM program that brings the plant through the design certification phase is described

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.

A Primer for DoD Reliability, Maintainability, Safety, and Logistics Standards, 1992

Science.gov (United States)

1991-10-01

Application of Reliability-Centered Maintenance to Naval Aircraft Weapon Systems and Support Equipment "* FMD -91 Failure Mode/Mechanism...Distributions ( FMD -91) available from the Reliability Analysis Center, HIT Research Institute, 201 Mill St., Rome, NY 13440-8200. 14.4 PHYSICAL...Fault Tree Analysis ( FTA ) (9) Sneak Circuit Analysis (10) Design Reviews Items (1) and (2) are addressed in Section 7 largely by reference to MIL

Establishing monitoring programs for travel time reliability. [supporting datasets

Science.gov (United States)

2014-01-01

The objective of this project was to develop system designs for programs to monitor travel time reliability and to prepare a guidebook that practitioners and others can use to design, build, operate, and maintain such systems. Generally, such travel ...

Reliability and Maintainability Analysis for the Amine Swingbed Carbon Dioxide Removal System

Science.gov (United States)

Dunbar, Tyler

2016-01-01

I have performed a reliability & maintainability analysis for the Amine Swingbed payload system. The Amine Swingbed is a carbon dioxide removal technology that has gone through 2,400 hours of International Space Station on-orbit use between 2013 and 2016. While the Amine Swingbed is currently an experimental payload system, the Amine Swingbed may be converted to system hardware. If the Amine Swingbed becomes system hardware, it will supplement the Carbon Dioxide Removal Assembly (CDRA) as the primary CO2 removal technology on the International Space Station. NASA is also considering using the Amine Swingbed as the primary carbon dioxide removal technology for future extravehicular mobility units and for the Orion, which will be used for the Asteroid Redirect and Journey to Mars missions. The qualitative component of the reliability and maintainability analysis is a Failure Modes and Effects Analysis (FMEA). In the FMEA, I have investigated how individual components in the Amine Swingbed may fail, and what the worst case scenario is should a failure occur. The significant failure effects are the loss of ability to remove carbon dioxide, the formation of ammonia due to chemical degradation of the amine, and loss of atmosphere because the Amine Swingbed uses the vacuum of space to regenerate the Amine Swingbed. In the quantitative component of the reliability and maintainability analysis, I have assumed a constant failure rate for both electronic and nonelectronic parts. Using this data, I have created a Poisson distribution to predict the failure rate of the Amine Swingbed as a whole. I have determined a mean time to failure for the Amine Swingbed to be approximately 1,400 hours. The observed mean time to failure for the system is between 600 and 1,200 hours. This range includes initial testing of the Amine Swingbed, as well as software faults that are understood to be non-critical. If many of the commercial parts were switched to military-grade parts, the expected

Solar Energy Grid Integration Systems (SEGIS): adding functionality while maintaining reliability and economics

Science.gov (United States)

Bower, Ward

2011-09-01

An overview of the activities and progress made during the US DOE Solar Energy Grid Integration Systems (SEGIS) solicitation, while maintaining reliability and economics is provided. The SEGIS R&D opened pathways for interconnecting PV systems to intelligent utility grids and micro-grids of the future. In addition to new capabilities are "value added" features. The new hardware designs resulted in smaller, less material-intensive products that are being viewed by utilities as enabling dispatchable generation and not just unpredictable negative loads. The technical solutions enable "advanced integrated system" concepts and "smart grid" processes to move forward in a faster and focused manner. The advanced integrated inverters/controllers can now incorporate energy management functionality, intelligent electrical grid support features and a multiplicity of communication technologies. Portals for energy flow and two-way communications have been implemented. SEGIS hardware was developed for the utility grid of today, which was designed for one-way power flow, for intermediate grid scenarios, AND for the grid of tomorrow, which will seamlessly accommodate managed two-way power flows as required by large-scale deployment of solar and other distributed generation. The SEGIS hardware and control developed for today meets existing standards and codes AND provides for future connections to a "smart grid" mode that enables utility control and optimized performance.

Space Station Freedom power - A reliability, availability, and maintainability assessment of the proposed Space Station Freedom electric power system

Science.gov (United States)

Turnquist, S. R.; Twombly, M.; Hoffman, D.

1989-01-01

A preliminary reliability, availability, and maintainability (RAM) analysis of the proposed Space Station Freedom electric power system (EPS) was performed using the unit reliability, availability, and maintainability (UNIRAM) analysis methodology. Orbital replacement units (ORUs) having the most significant impact on EPS availability measures were identified. Also, the sensitivity of the EPS to variations in ORU RAM data was evaluated for each ORU. Estimates were made of average EPS power output levels and availability of power to the core area of the space station. The results of assessments of the availability of EPS power and power to load distribution points in the space stations are given. Some highlights of continuing studies being performed to understand EPS availability considerations are presented.

Ultra Reliable Closed Loop Life Support for Long Space Missions

Science.gov (United States)

Jones, Harry W.; Ewert, Michael K.

2010-01-01

Spacecraft human life support systems can achieve ultra reliability by providing sufficient spares to replace all failed components. The additional mass of spares for ultra reliability is approximately equal to the original system mass, provided that the original system reliability is not too low. Acceptable reliability can be achieved for the Space Shuttle and Space Station by preventive maintenance and by replacing failed units. However, on-demand maintenance and repair requires a logistics supply chain in place to provide the needed spares. In contrast, a Mars or other long space mission must take along all the needed spares, since resupply is not possible. Long missions must achieve ultra reliability, a very low failure rate per hour, since they will take years rather than weeks and cannot be cut short if a failure occurs. Also, distant missions have a much higher mass launch cost per kilogram than near-Earth missions. Achieving ultra reliable spacecraft life support systems with acceptable mass will require a well-planned and extensive development effort. Analysis must determine the reliability requirement and allocate it to subsystems and components. Ultra reliability requires reducing the intrinsic failure causes, providing spares to replace failed components and having "graceful" failure modes. Technologies, components, and materials must be selected and designed for high reliability. Long duration testing is needed to confirm very low failure rates. Systems design should segregate the failure causes in the smallest, most easily replaceable parts. The system must be designed, developed, integrated, and tested with system reliability in mind. Maintenance and reparability of failed units must not add to the probability of failure. The overall system must be tested sufficiently to identify any design errors. A program to develop ultra reliable space life support systems with acceptable mass should start soon since it must be a long term effort.

Developing Ultra Reliable Life Support for the Moon and Mars

Science.gov (United States)

Jones, Harry W.

2009-01-01

Recycling life support systems can achieve ultra reliability by using spares to replace failed components. The added mass for spares is approximately equal to the original system mass, provided the original system reliability is not very low. Acceptable reliability can be achieved for the space shuttle and space station by preventive maintenance and by replacing failed units, However, this maintenance and repair depends on a logistics supply chain that provides the needed spares. The Mars mission must take all the needed spares at launch. The Mars mission also must achieve ultra reliability, a very low failure rate per hour, since it requires years rather than weeks and cannot be cut short if a failure occurs. Also, the Mars mission has a much higher mass launch cost per kilogram than shuttle or station. Achieving ultra reliable space life support with acceptable mass will require a well-planned and extensive development effort. Analysis must define the reliability requirement and allocate it to subsystems and components. Technologies, components, and materials must be designed and selected for high reliability. Extensive testing is needed to ascertain very low failure rates. Systems design should segregate the failure causes in the smallest, most easily replaceable parts. The systems must be designed, produced, integrated, and tested without impairing system reliability. Maintenance and failed unit replacement should not introduce any additional probability of failure. The overall system must be tested sufficiently to identify any design errors. A program to develop ultra reliable space life support systems with acceptable mass must start soon if it is to produce timely results for the moon and Mars.

An artificial neural network for modeling reliability, availability and maintainability of a repairable system

International Nuclear Information System (INIS)

Rajpal, P.S.; Shishodia, K.S.; Sekhon, G.S.

2006-01-01

The paper explores the application of artificial neural networks to model the behaviour of a complex, repairable system. A composite measure of reliability, availability and maintainability parameters has been proposed for measuring the system performance. The artificial neural network has been trained using past data of a helicopter transportation facility. It is used to simulate behaviour of the facility under various constraints. The insights obtained from results of simulation are useful in formulating strategies for optimal operation of the system

Experiences from maintaining the reliability of a nuclear standby diesel generator system

International Nuclear Information System (INIS)

Tammi, P.

1982-01-01

The nuclear standby diesel generator system is quite complicated comprising several mechanical and electrotechnical components, on which the reliability of the system is depending. It is an important support system of the plant safety system, and like the safety system it is composed of separate redundant units. The Loviisa nuclear power station has eight diesel generators. The first four of them were taken into operation in 1976. When the frequency of some mechanical failures showed increase, a project was started at the end of 1980 with the intention to find out potential failure possibilities and means for prevention of failures. The work has been mainly concentrated on improving the reliability of the diesel engines. (Auth.)

Waste Feed Delivery System Phase 1 Preliminary Reliability and Availability and Maintainability Analysis [SEC 1 and 2

International Nuclear Information System (INIS)

CARLSON, A.B.

1999-01-01

The document presents updated results of the preliminary reliability, availability, maintainability analysis performed for delivery of waste feed from tanks 241-AZ-101 and 241-AN-105 to British Nuclear Fuels Limited, inc. under the Tank Waste Remediation System Privatization Contract. The operational schedule delay risk is estimated and contributing factors are discussed

Waste Feed Delivery System Phase 1 Preliminary Reliability and Availability and Maintainability Analysis [SEC 1 and 2

Energy Technology Data Exchange (ETDEWEB)

CARLSON, A.B.

1999-11-11

The document presents updated results of the preliminary reliability, availability, maintainability analysis performed for delivery of waste feed from tanks 241-AZ-101 and 241-AN-105 to British Nuclear Fuels Limited, inc. under the Tank Waste Remediation System Privatization Contract. The operational schedule delay risk is estimated and contributing factors are discussed.

Further HTGR core support structure reliability studies. Interim report No. 1

International Nuclear Information System (INIS)

Platus, D.L.

1976-01-01

Results of a continuing effort to investigate high temperature gas cooled reactor (HTGR) core support structure reliability are described. Graphite material and core support structure component physical, mechanical and strength properties required for the reliability analysis are identified. Also described are experimental and associated analytical techniques for determining the required properties, a procedure for determining number of tests required, properties that might be monitored by special surveillance of the core support structure to improve reliability predictions, and recommendations for further studies. Emphasis in the study is directed towards developing a basic understanding of graphite failure and strength degradation mechanisms; and validating analytical methods for predicting strength and strength degradation from basic material properties

A new method for evaluating the availability, reliability, and maintainability whatever may be the probability law

International Nuclear Information System (INIS)

Doyon, L.R.; CEA Centre d'Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette

1975-01-01

A simple method is presented for computer solving every system model (availability, reliability, and maintenance) with intervals between failures, and time duration for repairs distributed according to any probability law, and for any maintainance policy. A matrix equation is obtained using Markov diagrams. An example is given with the solution by the APAFS program (Algorithme Pour l'Analyse de la Fiabilite des Systemes) [fr

Design for reliability: NASA reliability preferred practices for design and test

Science.gov (United States)

Lalli, Vincent R.

1994-01-01

This tutorial summarizes reliability experience from both NASA and industry and reflects engineering practices that support current and future civil space programs. These practices were collected from various NASA field centers and were reviewed by a committee of senior technical representatives from the participating centers (members are listed at the end). The material for this tutorial was taken from the publication issued by the NASA Reliability and Maintainability Steering Committee (NASA Reliability Preferred Practices for Design and Test. NASA TM-4322, 1991). Reliability must be an integral part of the systems engineering process. Although both disciplines must be weighed equally with other technical and programmatic demands, the application of sound reliability principles will be the key to the effectiveness and affordability of America's space program. Our space programs have shown that reliability efforts must focus on the design characteristics that affect the frequency of failure. Herein, we emphasize that these identified design characteristics must be controlled by applying conservative engineering principles.

Systems reliability analysis for the national ignition facility

International Nuclear Information System (INIS)

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

1996-01-01

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

Fast Monte Carlo reliability evaluation using support vector machine

International Nuclear Information System (INIS)

Rocco, Claudio M.; Moreno, Jose Ali

2002-01-01

This paper deals with the feasibility of using support vector machine (SVM) to build empirical models for use in reliability evaluation. The approach takes advantage of the speed of SVM in the numerous model calculations typically required to perform a Monte Carlo reliability evaluation. The main idea is to develop an estimation algorithm, by training a model on a restricted data set, and replace system performance evaluation by a simpler calculation, which provides reasonably accurate model outputs. The proposed approach is illustrated by several examples. Excellent system reliability results are obtained by training a SVM with a small amount of information

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

Institute of Scientific and Technical Information of China (English)

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

2011-01-01

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

Reliability and validity of the perspectives of Support From God Scale.

Science.gov (United States)

Hamilton, Jill B; Crandell, Jamie L; Carter, J Kameron; Lynn, Mary R

2010-01-01

Existing spiritual support scales for use with cancer survivors focus on the support believed to come from a religious community, clergy, or health care providers. The objective of this study was to evaluate the reliability and validity of a new measure of spiritual support believed to come from God in older Christian African American cancer survivors. The Perceived Support From God Scale was administered to 317 African American cancer survivors aged 55-89 years. Psychometric evaluation involved identifying underlying factors, conducting item analysis and estimating reliability, and obtaining evidence on the relationship to other variables or the extent to which the Perceived Support From God Scale correlates with religious involvement and depression. The Perceived Support From God Scale consists of 15 items in two subscales (Support From God and God's Purpose for Me). The two subscales explained 59% of the variance. Cronbach's alpha coefficients were .94 and .86 for the Support From God and God's Purpose for Me subscales, respectively. Test-retest correlations were strong, supporting the temporal stability of the instrument. Pearson's correlations to an existing religious involvement and beliefs scale were moderate to strong. Subscale scores on Support From God were negatively correlated to depression. Initial support for reliability and validity was demonstrated for the Perceived Support From God Scale. The scale captures a facet of spirituality not emphasized in other measures. Further research is needed to evaluate the scale with persons of other racial/ethnic groups and to explore the relationship of spirituality to other outcome measures.

Piping reliability improvement through passive seismic supports

International Nuclear Information System (INIS)

Baltus, R.; Rubbers, A.

1999-01-01

The nuclear plants designed in the 1970's were equipped with large quantities of snubbers in auxiliary piping systems. The experience revealed a poor performance of snubbers during periodic inspection, while non-nuclear facility piping survived through strong earthquakes. Consequently, seismic design rules evolved towards more realistic criteria and passive dynamic supports were developed to reduce snubber quantities. These solutions improve the pipe reliability during normal operation while reducing the radiation exposure in a sample line is presented with the impact on pipe stresses compared to the results obtained with passive supports named Limit Stops. (author)

Training and Maintaining System-Wide Reliability in Outcome Management.

Science.gov (United States)

Barwick, Melanie A; Urajnik, Diana J; Moore, Julia E

2014-01-01

The Child and Adolescent Functional Assessment Scale (CAFAS) is widely used for outcome management, for providing real time client and program level data, and the monitoring of evidence-based practices. Methods of reliability training and the assessment of rater drift are critical for service decision-making within organizations and systems of care. We assessed two approaches for CAFAS training: external technical assistance and internal technical assistance. To this end, we sampled 315 practitioners trained by external technical assistance approach from 2,344 Ontario practitioners who had achieved reliability on the CAFAS. To assess the internal technical assistance approach as a reliable alternative training method, 140 practitioners trained internally were selected from the same pool of certified raters. Reliabilities were high for both practitioners trained by external technical assistance and internal technical assistance approaches (.909-.995, .915-.997, respectively). 1 and 3-year estimates showed some drift on several scales. High and consistent reliabilities over time and training method has implications for CAFAS training of behavioral health care practitioners, and the maintenance of CAFAS as a global outcome management tool in systems of care.

Basic conceptions for development of new-type high-efficiency cooling towers with enhanced reliability, maneuverability and maintainability

International Nuclear Information System (INIS)

Kim En Be; Nedviga, Yu.S.

1990-01-01

The state-of-the-art of cooling tower design, construction and operation is analysed. From the analysis formulated are general requirements which can be imposed upon cooling towers serving as most important technological apparatuses in water supply systems of thermal and nuclear power plants. With these requirements taken into account, basic research and technical conceptions are developed to be used in designing new-type cooling towers characterized by enhanced reliability, maneuverability and maintainability

Four-train support always more reliable than a two-train support?

International Nuclear Information System (INIS)

Guey, C.N.; Arrieta, L.; Youngblood, R.

1986-01-01

Once the gross features of a frontline fluid system have been defined, one must consider what support system configuration will provide the best overall system performance. This paper considers different direct-current (dc) bus configurations for a given emergency feedwater system (EFWS). Results indicate that a four-train support system (i.e., 4 dc buses) gives a lower system unavailability for transients, but a higher system unavailability for anticipated transients without scram (ATWSs), than a two-train support system (i.e., two dc buses). This serves to illustrate that more trains do not necessarily provide higher reliability, and that a configuration choice which is better for one emission success criterion may be worse for another. Because of the small characteristic unreliability of dc buses, the numerical comparisons made here are not dramatic, but the underlying topological point is nevertheless broadly applicable

Reliability engineering

International Nuclear Information System (INIS)

Lee, Chi Woo; Kim, Sun Jin; Lee, Seung Woo; Jeong, Sang Yeong

1993-08-01

This book start what is reliability? such as origin of reliability problems, definition of reliability and reliability and use of reliability. It also deals with probability and calculation of reliability, reliability function and failure rate, probability distribution of reliability, assumption of MTBF, process of probability distribution, down time, maintainability and availability, break down maintenance and preventive maintenance design of reliability, design of reliability for prediction and statistics, reliability test, reliability data and design and management of reliability.

Pilot testing of SHRP 2 reliability data and analytical products: Southern California. [supporting datasets

Science.gov (United States)

2014-01-01

The objective of this project was to develop system designs for programs to monitor travel time reliability and to prepare a guidebook that practitioners and others can use to design, build, operate, and maintain such systems. Generally, such travel ...

Reliability Engineering

International Nuclear Information System (INIS)

Lee, Sang Yong

1992-07-01

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

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

International Nuclear Information System (INIS)

Yokobayashi, Masao; Tamura, Kazuo.

1995-10-01

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

Recommended techniques for effective maintainability. A continuous improvement initiative of the NASA Reliability and Maintainability Steering Committee

Science.gov (United States)

1994-01-01

This manual presents a series of recommended techniques that can increase overall operational effectiveness of both flight and ground based NASA systems. It provides a set of tools that minimizes risk associated with: (1) restoring failed functions (both ground and flight based); (2) conducting complex and highly visible maintenance operations; and (3) sustaining a technical capability to support the NASA mission using aging equipment or facilities. It considers (1) program management - key elements of an effective maintainability effort; (2) design and development - techniques that have benefited previous programs; (3) analysis and test - quantitative and qualitative analysis processes and testing techniques; and (4) operations and operational design techniques that address NASA field experience. This document is a valuable resource for continuous improvement ideas in executing the systems development process in accordance with the NASA 'better, faster, smaller, and cheaper' goal without compromising safety.

Failure and reliability prediction by support vector machines regression of time series data

International Nuclear Information System (INIS)

Chagas Moura, Marcio das; Zio, Enrico; Lins, Isis Didier; Droguett, Enrique

2011-01-01

Support Vector Machines (SVMs) are kernel-based learning methods, which have been successfully adopted for regression problems. However, their use in reliability applications has not been widely explored. In this paper, a comparative analysis is presented in order to evaluate the SVM effectiveness in forecasting time-to-failure and reliability of engineered components based on time series data. The performance on literature case studies of SVM regression is measured against other advanced learning methods such as the Radial Basis Function, the traditional MultiLayer Perceptron model, Box-Jenkins autoregressive-integrated-moving average and the Infinite Impulse Response Locally Recurrent Neural Networks. The comparison shows that in the analyzed cases, SVM outperforms or is comparable to other techniques. - Highlights: → Realistic modeling of reliability demands complex mathematical formulations. → SVM is proper when the relation input/output is unknown or very costly to be obtained. → Results indicate the potential of SVM for reliability time series prediction. → Reliability estimates support the establishment of adequate maintenance strategies.

An information system supporting design for reliability and maintenance

International Nuclear Information System (INIS)

Rit, J.F.; Beraud, M.T.

1997-01-01

EDF is currently developing a methodology to integrate availability, operating experience and maintenance in the design of power plants. This involves studies that depend closely on the results and assumptions of each other about the reliability and operations of the plant. Therefore a support information system must be carefully designed. Concurrently with development of the methodology, a research oriented information system was designed and built. It is based on the database model of a logistic support repository that we tailored to our needs. (K.A.)

An information system supporting design for reliability and maintenance

Energy Technology Data Exchange (ETDEWEB)

Rit, J.F.; Beraud, M.T

1997-12-31

EDF is currently developing a methodology to integrate availability, operating experience and maintenance in the design of power plants. This involves studies that depend closely on the results and assumptions of each other about the reliability and operations of the plant. Therefore a support information system must be carefully designed. Concurrently with development of the methodology, a research oriented information system was designed and built. It is based on the database model of a logistic support repository that we tailored to our needs. (K.A.) 10 refs.

Supporting the personnel reliability decision-making process with artificial intelligence

International Nuclear Information System (INIS)

Harte, D.C.

1991-01-01

Recent legislation concerning personnel security has vastly increased the responsibility and accountability of the security manager. Access authorization, fitness for duty, and personnel security access programs require decisions regarding an individual's trustworthiness and reliability based on the findings of a background investigation. While these guidelines provide significant data and are useful as a tool, limited resources are available to the adjudicator of derogatory information on what is and is not acceptable in terms of granting access to sensitive areas of nuclear plants. The reason why one individual is deemed unacceptable and the next acceptable may be questioned and cause discriminatory accusations. This paper is continuation of discussion on workforce reliability, focusing on the use of artificial intelligence to support the decisions of a security manager. With this support, the benefit of previous decisions helps ensure consistent adjudication of background investigations

Measuring participation of social-support clients: : validity and reliability of IPA-MO

NARCIS (Netherlands)

Berenschot, L.; Grift, Y.K.

2017-01-01

This study evaluates the reliability and validity of the Impact on Autonomy and Participation instrument (IPA) for heterogeneous populations of social support clients. Decentralisation of social support and accompanying budget cuts spurred interest in outcome-related payment systems to foster

76 FR 58101 - Electric Reliability Organization Interpretation of Transmission Operations Reliability Standard

Science.gov (United States)

2011-09-20

....C. Cir. 2009). \\4\\ Mandatory Reliability Standards for the Bulk-Power System, Order No. 693, FERC... for maintaining real and reactive power balance. \\14\\ Electric Reliability Organization Interpretation...; Order No. 753] Electric Reliability Organization Interpretation of Transmission Operations Reliability...

User`s manual of a support system for human reliability analysis

Energy Technology Data Exchange (ETDEWEB)

Yokobayashi, Masao [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Tamura, Kazuo

1995-10-01

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

Revisiting Frequency Reuse towards Supporting Ultra-Reliable Ubiquitous-Rate Communication

DEFF Research Database (Denmark)

Park, Jihong; Kim, Dong Min; Popovski, Petar

2017-01-01

One of the goals of 5G wireless systems stated by the NGMN alliance is to provide moderate rates (50+ Mbps) everywhere and with very high reliability. We term this service Ultra-Reliable Ubiquitous-Rate Communication (UR2C). This paper investigates the role of frequency reuse in supporting UR2C...... in the downlink. To this end, two frequency reuse schemes are considered: user-specific frequency reuse (FRu) and BS-specific frequency reuse (FRb). For a given unit frequency channel, FRu reduces the number of serving user equipments (UEs), whereas FRb directly decreases the number of interfering base stations...

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

OpenAIRE

Zhang, Yang; Prescott, Darren

2017-01-01

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

Management of reliability and maintainability; a disciplined approach to fleet readiness

Science.gov (United States)

Willoughby, W. J., Jr.

1981-01-01

Material acquisition fundamentals were reviewed and include: mission profile definition, stress analysis, derating criteria, circuit reliability, failure modes, and worst case analysis. Military system reliability was examined with emphasis on the sparing of equipment. The Navy's organizational strategy for 1980 is presented.

Monte Carlo simulation - a powerful tool to support experimental activities in structure reliability

International Nuclear Information System (INIS)

Yuritzinn, T.; Chapuliot, S.; Eid, M.; Masson, R.; Dahl, A.; Moinereau, D.

2003-01-01

Monte-Carlo Simulation (MCS) can have different uses in supporting structure reliability investigations and assessments. In this paper we focus our interest on the use of MCS as a numerical tool to support the fitting of the experimental data related to toughness experiments. (authors)

Examining the Reliability and Validity of the Effective Behavior Support Self-Assessment Survey

Science.gov (United States)

Solomon, Benjamin G.; Tobin, Kevin G.; Schutte, Gregory M.

2015-01-01

The Effective Behavior Support Self-Assessment Survey (SAS; Sugai, Horner, & Todd, 2003) is designed to measure perceived Positive Behavior Interventions and Supports (PBIS) implementation and identify priorities for improvement. Despite its longevity, little published research exists documenting its reliability or validity for these purposes.…

Reliability analysis of idealized tunnel support system using probability-based methods with case studies

NARCIS (Netherlands)

Gharouni-Nik, M.; Naeimi, M.; Ahadi, S.; Alimoradi, Z.

2014-01-01

In order to determine the overall safety of a tunnel support lining, a reliability-based approach is presented in this paper. Support elements in jointed rock tunnels are provided to control the ground movement caused by stress redistribution during the tunnel drive. Main support elements contribute

Forward Capacity Markets: Maintaining Grid Reliability in Europe

OpenAIRE

Chaigneau, Matthieu

2012-01-01

The liberalization process of the electricity industry in many countries leads to new rules and new challenges for the grid management. System reliability is a major concern, mainly because of (a) the high level penetration of renewable energy sources and (b) the growing peak load and environmental regulations In most electricity markets, peak resources operate only during a short period, and at a high operating cost, jeopardizing their return on investment, while low-cost base resources make...

Advanced remotely maintainable force-reflecting servomanipulator concept

International Nuclear Information System (INIS)

Kuban, D.P.; Martin, H.L.

1984-01-01

A remotely maintainable force-reflecting servomanipulator concept is being developed at the Oak Ridge National Laboratory as part of the Consolidated Fuel Reprocessing Program. This new manipulator addresses requirements of advanced nuclear fuel reprocessing with emphasis on force reflection, remote maintainability, reliability, radiation tolerance, and corrosion resistance. The advanced servomanipulator is uniquely subdivided into remotely replaceable modules which will permit in situ manipulator repair by spare module replacement. Manipulator modularization and increased reliability are accomplished through a force transmission system that uses gears and torque tubes. Digital control algorithms and mechanical precision are used to offset the increased backlash, friction, and inertia resulting from the gear drives. This results in the first remotely maintainable force-reflecting servomanipulator in the world. 10 references, 4 figures, 1 table

Forecasting systems reliability based on support vector regression with genetic algorithms

International Nuclear Information System (INIS)

Chen, K.-Y.

2007-01-01

This study applies a novel neural-network technique, support vector regression (SVR), to forecast reliability in engine systems. The aim of this study is to examine the feasibility of SVR in systems reliability prediction by comparing it with the existing neural-network approaches and the autoregressive integrated moving average (ARIMA) model. To build an effective SVR model, SVR's parameters must be set carefully. This study proposes a novel approach, known as GA-SVR, which searches for SVR's optimal parameters using real-value genetic algorithms, and then adopts the optimal parameters to construct the SVR models. A real reliability data for 40 suits of turbochargers were employed as the data set. The experimental results demonstrate that SVR outperforms the existing neural-network approaches and the traditional ARIMA models based on the normalized root mean square error and mean absolute percentage error

Perceived Benefits and Factors that Influence the Ability to Establish and Maintain Patient Support Groups in Rare Diseases: A Scoping Review.

Science.gov (United States)

Delisle, Vanessa C; Gumuchian, Stephanie T; Rice, Danielle B; Levis, Alexander W; Kloda, Lorie A; Körner, Annett; Thombs, Brett D

2017-06-01

Support groups are an important resource for many people living with rare diseases. The perceived benefits of participating in support groups for people with rare diseases and factors that may influence the ability to successfully establish and maintain these groups are not well understood. Thus, the objective of this scoping review was to provide a mapping of the available evidence on the (1) benefits or perceived benefits of participating in rare disease support groups and (2) barriers and facilitators of establishing and maintaining these groups. CINAHL and PubMed were searched from January 2000 to August 2015, with no language restrictions. Publications that described the benefits or perceived benefits of participating in rare disease support groups or the barriers and facilitators of establishing and maintaining them were eligible for inclusion. Two investigators independently evaluated titles/abstracts and full-text publications for eligibility, and extracted data from each included publication. Ten publications were included in the scoping review. There was no trial evidence on support group benefits. All ten publications reported on the perceived benefits of participating in rare disease support groups. Three reported on barriers and facilitators of establishing and maintaining them. Overall, seven different perceived benefits of participating in rare disease support groups were identified: (1) meeting and befriending other people with the same rare disease and similar experiences; (2) learning about the disease and related treatments; (3) giving and receiving emotional support; (4) having a place to speak openly about the disease and one's feelings; (5) learning coping skills; (6) feeling empowered and hopeful; and (7) advocating to improve healthcare for other rare disease patients. Several facilitators (e.g., meeting via teleconference) and barriers (e.g., getting patients and/or family members to lead the group) of establishing and maintaining these

Direct unavailability computation of a maintained highly reliable system

Czech Academy of Sciences Publication Activity Database

Briš, R.; Byczanski, Petr

2010-01-01

Roč. 224, č. 3 (2010), s. 159-170 ISSN 1748-0078 Grant - others:GA Mšk(CZ) MSM6198910007 Institutional research plan: CEZ:AV0Z30860518 Keywords : high reliability * availability * directed acyclic graph Subject RIV: BA - General Mathematics http:// journals .pepublishing.com/content/rtp3178l17923m46/

Reliability and validity of a physical activity social support assessment scale in adolescents - ASAFA Scale

Directory of Open Access Journals (Sweden)

José Cazuza de Farias Júnior

2014-06-01

Full Text Available Objective: To analyze the reliability and validity of a scale used to measure social support for physical activity in adolescents - ASAFA Scale. Methods: This study included 2,755 adolescents (57.6% girls, 16.5 ± 1.2 years of age, from Joao Pessoa, Paraiba, Brazil. Initially, the scale was consisted of 12 items (6 for social support from parents and 6 from friends. The reliability of the scale was estimated by Cronbach's alpha coefficient (α, by the Composite Reliability (CR, and by the model with two factors and factorial invariance by Confirmatory Factor Analysis (CFA adequacy. Results: The CFA results confirmed that the social support scale contained two factors (factor 1: social support from parents; factor 2: social support from friends with five items each (one item was excluded from each scale, all with high factor loadings (> 0.65 and acceptable adjustment indexes (RMR = 0.050; RMSEA = 0.063; 90%CI: 0.060 - 0.067; AGFI = 0.903; GFI = 0.940; CFI = 0.934, NNFI = 0.932. The internal consistency was satisfactory (parents: α ≥ 0.77 and CR ≥ 0.83; friends: α ≥ 0.87 and CR ≥ 0.91. The scale's factorial invariance was confirmed (p > 0.05; Δχ2 and ΔCFI ≤ 0.01 across all subgroups analyzed (gender, age, economic class. The construct validity was evidenced by the significant association (p < 0.05 between the adolescents physical activity level and the social support score of parents (rho = 0.29 and friends (rho = 0.39. Conclusions: The scale showed reliability, factorial invariance and satisfactory validity, so it can be used in studies with adolescents.

A support vector density-based importance sampling for reliability assessment

International Nuclear Information System (INIS)

Dai, Hongzhe; Zhang, Hao; Wang, Wei

2012-01-01

An importance sampling method based on the adaptive Markov chain simulation and support vector density estimation is developed in this paper for efficient structural reliability assessment. The methodology involves the generation of samples that can adaptively populate the important region by the adaptive Metropolis algorithm, and the construction of importance sampling density by support vector density. The use of the adaptive Metropolis algorithm may effectively improve the convergence and stability of the classical Markov chain simulation. The support vector density can approximate the sampling density with fewer samples in comparison to the conventional kernel density estimation. The proposed importance sampling method can effectively reduce the number of structural analysis required for achieving a given accuracy. Examples involving both numerical and practical structural problems are given to illustrate the application and efficiency of the proposed methodology.

Reliability of decision-support systems for nuclear emergency management

Energy Technology Data Exchange (ETDEWEB)

Ionescu, Tudor B.

2013-08-15

Decision support systems for nuclear emergency management (DSNE) are currently used worldwide to assist decision makers in taking emergency response countermeasures in case of accidental releases of radioactive materials from nuclear facilities. The present work has been motivated by the fact that, up until now, DSNE systems have not been regarded as safetycritical software systems, such as embedded software currently being used in vehicles and aircraft. The core of any DSNE system is represented by the different simulation codes linked together to form the dispersion simulation workflow. These codes require input emission and meteorological data to produce forecasts of the atmospheric dispersion of radioactive pollutants and other substances. However, the reliability of the system not only depends on the trustworthiness of the measured (or generated) input data but also on the reliability of the simulation codes used. The main goal of this work is to improve the reliability of DSNE systems by adapting current state of the art methods from the domain of software reliability engineering to the case of atmospheric dispersion simulation codes. The current approach is based on the design by diversity principle for improving the reliability of codes and the trustworthiness of results as well as on a flexible fault-tolerant workflow scheduling algorithm for ensuring the maximum availability of the system. The author's contribution is represented by (i) an acceptance test for dispersion simulation results, (ii) an adjudication algorithm (voter) based on comparing taxonomies of dispersion simulation results, and (iii) a feedback-control based fault-tolerant workflow scheduling algorithm. These tools provide means for the continuous verification of dispersion simulation codes while tolerating timing faults caused by disturbances in the underlying computational environment and will thus help increase the reliability and trustworthiness of DSNE systems in missioncritical

Reliability of decision-support systems for nuclear emergency management

International Nuclear Information System (INIS)

Ionescu, Tudor B.

2013-08-01

Decision support systems for nuclear emergency management (DSNE) are currently used worldwide to assist decision makers in taking emergency response countermeasures in case of accidental releases of radioactive materials from nuclear facilities. The present work has been motivated by the fact that, up until now, DSNE systems have not been regarded as safetycritical software systems, such as embedded software currently being used in vehicles and aircraft. The core of any DSNE system is represented by the different simulation codes linked together to form the dispersion simulation workflow. These codes require input emission and meteorological data to produce forecasts of the atmospheric dispersion of radioactive pollutants and other substances. However, the reliability of the system not only depends on the trustworthiness of the measured (or generated) input data but also on the reliability of the simulation codes used. The main goal of this work is to improve the reliability of DSNE systems by adapting current state of the art methods from the domain of software reliability engineering to the case of atmospheric dispersion simulation codes. The current approach is based on the design by diversity principle for improving the reliability of codes and the trustworthiness of results as well as on a flexible fault-tolerant workflow scheduling algorithm for ensuring the maximum availability of the system. The author's contribution is represented by (i) an acceptance test for dispersion simulation results, (ii) an adjudication algorithm (voter) based on comparing taxonomies of dispersion simulation results, and (iii) a feedback-control based fault-tolerant workflow scheduling algorithm. These tools provide means for the continuous verification of dispersion simulation codes while tolerating timing faults caused by disturbances in the underlying computational environment and will thus help increase the reliability and trustworthiness of DSNE systems in missioncritical

Exploitation examination of reliability of coal dust systems

International Nuclear Information System (INIS)

Dojchinovski, Ilija; Trajkovski, Kole

1997-01-01

Designers and operators wish is, long, failure free operation at designed parameters of every system. Always we know the system start up time, but we don't know how long this system will operate successfully. Because of that in this article is given a method how, step by step, to determine the reliability of the system. Reliability parameters are obtained from experimental and operational data. When reliability parameters are determined then it is very easy to compare reliability of similar systems, for example excavators, or different systems, such as truck and rubber band transport system. Practical use of the theory of reliability is by purchasing of the systems when manufacturers have to have and present reliability parameters and on this way we can decide which system satisfies our needs regarding the quality-price-reliability. Reliability can be practically used in system operation where: 1) system reliability is maintained with proper start, use and shutdown of the system; 2) a system reliability is maintained with good maintenance organization; 3) a system reliability is maintained with innovations and improvements with final purpose removing of the imperfections experienced through the operation. Reliability is very important parameter in power generation plants. (Author)

Evaluating validity and reliability of Persian version of Supports Intensity Scale in adults with intellectual disability

Directory of Open Access Journals (Sweden)

Shahin Soltani

2013-12-01

Full Text Available Background: Shifting paradigms regarding the ways to assess the support needs of people with intellectual disability in 1980 necessitates the design and development of appropriate tools more than ever. In this regard, American Association on Intellectual and Developmental Disabilities (AAIDD developed Supports Intensity Scale (SIS to respond the lack of an appropriate measurement tool. The aim of this study is the cultural adaptation and evaluation of psychometric properties of Supports Intensity Scale in adults with intellectual disability. Methods: Validity of Persian version of SIS was assessed by Content validity. The reliability of the scale was evaluated using Cronbach's alpha and test–retest reliability with a 3-week interval. In this study, the sample contained 43 adults (29 men and 14 women with intellectual disability. Results: The content of the Persian version of SIS was approved by the experts. The Cronbach's alpha reliability coefficients for the subscales ranged between 0.80 and 0.99. Also, Intraclass correlation coefficients ranged between 0.90 and 0.99 (P<0.001. Furthermore, all Pearson correlation coefficients among the SIS subscales ranged between 0.63 and 0.98 (P<0.01. Conclusion: The results of this study indicated that the validity and reliability of the equivalent Persian version of SIS for identifying pattern and required supports intensity in adults with intellectual disability is acceptable.

Development of Chinese Military Personnel Social Support Scale and tests for its reliability and validity

Directory of Open Access Journals (Sweden)

Kai-hong TANG

2013-01-01

Full Text Available Objective 　To develop Chinese Military Personnel Social Support Scaleand verify its reliability and validity. Methods 　The Chinese Military Personnel Social Support Scalewas initiated, organized and compiled based upon open-ended questionnaire survey done in a systematic manner, and previous researches were taken as references. A total of 630 military personnel were chosen by random cluster sampling and tested with the Scale, among them 50 were tested with Social Support Rating Scale(SSRS and Chinese Military Psychosomatic Health Scale(CMPHS simultaneously, and the test was done solely a second time with CMPHS 2 weeks later. The reliability and validity were assessed and verified by exploratory factor analysis, confirmatory factor analysis and correlation analysis. Results 　The Chinese Military Personnel Social Support Scalecomprised three factors, namely subjective support, objective support and utility of social support. Eighteen items were left in official scale after amendment by factor analysis, and one lying subscale was added. The correlation coefficients between the public factors ranged from 0.477 to 0.589 (P<0.01, and the correlation coefficients between factors and total scale ranged from 0.721 to 0.823 (P<0.01. The test-retest correlation coefficients of total scale and subscales ranged from 0.622 to 0.803 (P<0.01, the Cronbach α coefficients ranged from 0.624 to 0.874, and the split-half correlation coefficients ranged from 0.551 to 0.828. Significant correlation existed between this Scale and two criterion scales, namely SSRS and CMPHS. Conclusion 　It is verified that the Chinese Military Personnel Social Support Scalehas excellent reliability and validity, and complying with psychometric standards, it may be used to evaluate the social support level of Chinese military personnel.

Stochastic models in reliability and maintenance

CERN Document Server

2002-01-01

Our daily lives can be maintained by the high-technology systems. Computer systems are typical examples of such systems. We can enjoy our modern lives by using many computer systems. Much more importantly, we have to maintain such systems without failure, but cannot predict when such systems will fail and how to fix such systems without delay. A stochastic process is a set of outcomes of a random experiment indexed by time, and is one of the key tools needed to analyze the future behavior quantitatively. Reliability and maintainability technologies are of great interest and importance to the maintenance of such systems. Many mathematical models have been and will be proposed to describe reliability and maintainability systems by using the stochastic processes. The theme of this book is "Stochastic Models in Reliability and Main­ tainability. " This book consists of 12 chapters on the theme above from the different viewpoints of stochastic modeling. Chapter 1 is devoted to "Renewal Processes," under which cla...

Computer Support for Conducting Supportability Trade-Offs in a Team Setting

Science.gov (United States)

1990-01-01

with the ability of the product to be satisfactorily maintained throughout its intended useful life span with minimum expenditures of money and effort...during the pre-concept phase, thereby ensuring a reduction in cost due to reducing eventual retrofits, and a more supportable weapon system. Lauder ...It is shown that although large sums of money are expended on producing reliable components, these are vitiated if the end equipment is not exposed

The reliability of integrated gasification combined cycle (IGCC) power generation units

Energy Technology Data Exchange (ETDEWEB)

Higman, C.; DellaVilla, S.; Steele, B. [Syngas Consultants Ltd. (United Kingdom)

2006-07-01

This paper presents two interlinked projects aimed at supporting the improvement of integrated gasification combined cycle (IGCC) reliability. The one project comprises the extension of SPS's existing ORAP (Operational Reliability Analysis Program) reliability, availability and maintainability (RAM) tracking technology from its existing base in natural gas open and combined cycle operations into IGCC. The other project is using the extended ORAP database to evaluate performance data from existing plants. The initial work has concentrated on evaluating public domain data on the performance of gasification based power and chemical plants. This is being followed up by plant interviews in some 20 plants to verify and expand the database on current performance. 23 refs., 8 figs., 2 tabs.

Delivering on Industry Equipment Reliability Goals By Leveraging an Integration Platform and Decision Support Environment

International Nuclear Information System (INIS)

Coveney, Maureen K.; Bailey, W. Henry; Parkinson, William

2004-01-01

Utilities have invested in many costly enterprise systems - computerized maintenance management systems, document management systems, enterprise grade portals, to name but a few - and often very specialized systems, like data historians, high end diagnostic systems, and other focused and point solutions. From recent industry reports, we now know that the average nuclear power utilizes on average 1900 systems to perform daily work, of which 250 might facilitate the equipment reliability decision-making process. The time has come to leverage the investment in these systems by providing a common platform for integration and decision-making that will further the collective industry aim of enhancing the reliability of our nuclear generation assets to maintain high plant availability and to deliver on plant life extension goals without requiring additional large scale investment in IT infrastructure. (authors)

Reliability of Wind Speed Data from Satellite Altimeter to Support Wind Turbine Energy

Science.gov (United States)

Uti, M. N.; Din, A. H. M.; Omar, A. H.

2017-10-01

Satellite altimeter has proven itself to be one of the important tool to provide good quality information in oceanographic study. Nowadays, most countries in the world have begun in implementation the wind energy as one of their renewable energy for electric power generation. Many wind speed studies conducted in Malaysia using conventional method and scientific technique such as anemometer and volunteer observing ships (VOS) in order to obtain the wind speed data to support the development of renewable energy. However, there are some limitations regarding to this conventional method such as less coverage for both spatial and temporal and less continuity in data sharing by VOS members. Thus, the aim of this research is to determine the reliability of wind speed data by using multi-mission satellite altimeter to support wind energy potential in Malaysia seas. Therefore, the wind speed data are derived from nine types of satellite altimeter starting from year 1993 until 2016. Then, to validate the reliability of wind speed data from satellite altimeter, a comparison of wind speed data form ground-truth buoy that located at Sabah and Sarawak is conducted. The validation is carried out in terms of the correlation, the root mean square error (RMSE) calculation and satellite track analysis. As a result, both techniques showing a good correlation with value positive 0.7976 and 0.6148 for point located at Sabah and Sarawak Sea, respectively. It can be concluded that a step towards the reliability of wind speed data by using multi-mission satellite altimeter can be achieved to support renewable energy.

Long-term Mechanical Circulatory Support System reliability recommendation by the National Clinical Trial Initiative subcommittee.

Science.gov (United States)

Lee, James

2009-01-01

The Long-Term Mechanical Circulatory Support (MCS) System Reliability Recommendation was published in the American Society for Artificial Internal Organs (ASAIO) Journal and the Annals of Thoracic Surgery in 1998. At that time, it was stated that the document would be periodically reviewed to assess its timeliness and appropriateness within 5 years. Given the wealth of clinical experience in MCS systems, a new recommendation has been drafted by consensus of a group of representatives from the medical community, academia, industry, and government. The new recommendation describes a reliability test methodology and provides detailed reliability recommendations. In addition, the new recommendation provides additional information and clinical data in appendices that are intended to assist the reliability test engineer in the development of a reliability test that is expected to give improved predictions of clinical reliability compared with past test methods. The appendices are available for download at the ASAIO journal web site at www.asaiojournal.com.

Is a 4-train support ''always'' more reliable than a 2-train support

International Nuclear Information System (INIS)

Guey, C.N.; Arrieta, L.; Youngblood, R.

1986-06-01

Once the gross features of a frontline fluid system have been defined, one must consider what support system configuration will provide the best overall system performance. This paper considers different dc bus configurations for a given emergency feedwater system. Results indicate that a four-train support system (i.e., 4 dc buses) gives a lower system unavailability for transients, but a higher system unavailability for Anticipated Transients Without Scram (ATWS), than a two-train support system (i.e., two dc buses). This serves to illustrate that more trains do not necessarily provide higher reliability, and that a configuration choice which is better for one mission success criterion may be worse for another. Because of the small characteristic unreliability of dc buses, the numerical comparisons made here are not dramatic, but the underlying topological point is nevertheless broadly applicable. The EFWS selected in this study consists of two turbine-driven pumps, and two motor-driven pumps, with associated piping, instruments, and valves. There are two divisions of EFWS, each division including one turbine-driven pump train, and one motor-driven pump train with a crosstie that can provide an alternate flow path in case one train is not available. Each of the motor-driven pumps has one ac power bus associated with it. No ac power is required for the turbine-driven trains

Compliance and High Reliability in a Complex Healthcare Organization.

Science.gov (United States)

Simon, Maxine dellaBadia

2018-01-01

When considering the impact of regulation on healthcare, visualize a spider's web. The spider weaves sections together to create the whole, with each fiber adding to the structure to support its success or lead to its failure. Each section is dependent on the others, and all must be aligned to maintain the structure. Outside forces can cause a shift in the web's fragile equilibrium.The interdependence of the sections of the spider's web is similar to the way hospital departments and services work together. An organization's structure must be shaped to support its mission and vision. At the same time, the business of healthcare requires the development and achievement of operational objectives and financial performance goals. Establishing a culture that is flexible enough to permit creativity, provide resiliency, and manage complexity as the organization grows is fundamental to success. An organization must address each of these factors while maintaining stability, carrying out its mission, and fostering improvement.Nature's order maintains the spider's web. Likewise, regulation can strengthen healthcare organizations by initiating disruptive changes that can support efforts to achieve and sustain high reliability in the delivery of care. To that end, leadership must be willing to provide the necessary vision and resources.

Operational safety reliability research

International Nuclear Information System (INIS)

Hall, R.E.; Boccio, J.L.

1986-01-01

Operating reactor events such as the TMI accident and the Salem automatic-trip failures raised the concern that during a plant's operating lifetime the reliability of systems could degrade from the design level that was considered in the licensing process. To address this concern, NRC is sponsoring the Operational Safety Reliability Research project. The objectives of this project are to identify the essential tasks of a reliability program and to evaluate the effectiveness and attributes of such a reliability program applicable to maintaining an acceptable level of safety during the operating lifetime at the plant

Reliability analysis techniques in power plant design

International Nuclear Information System (INIS)

Chang, N.E.

1981-01-01

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

Improved Reliability-Based Optimization with Support Vector Machines and Its Application in Aircraft Wing Design

Directory of Open Access Journals (Sweden)

Yu Wang

2015-01-01

Full Text Available A new reliability-based design optimization (RBDO method based on support vector machines (SVM and the Most Probable Point (MPP is proposed in this work. SVM is used to create a surrogate model of the limit-state function at the MPP with the gradient information in the reliability analysis. This guarantees that the surrogate model not only passes through the MPP but also is tangent to the limit-state function at the MPP. Then, importance sampling (IS is used to calculate the probability of failure based on the surrogate model. This treatment significantly improves the accuracy of reliability analysis. For RBDO, the Sequential Optimization and Reliability Assessment (SORA is employed as well, which decouples deterministic optimization from the reliability analysis. The improved SVM-based reliability analysis is used to amend the error from linear approximation for limit-state function in SORA. A mathematical example and a simplified aircraft wing design demonstrate that the improved SVM-based reliability analysis is more accurate than FORM and needs less training points than the Monte Carlo simulation and that the proposed optimization strategy is efficient.

Maintaining normality and support are central issues when receiving chemotherapy for ovarian cancer.

Science.gov (United States)

Ekman, Inger; Bergbom, Ingegerd; Ekman, Tor; Berthold, Harrieth; Mahsneh, Sawsan Majali

2004-01-01

The aim of this study was to enrich the understanding of patients' perspective of being diagnosed and treated for ovarian cancer. A qualitative approach was used to obtain knowledge and insight into patients' experiences and thoughts. Ten Swedish women, diagnosed with ovarian cancer, participated in a total of 23 interviews on 3 occasions: at the time of diagnosis, during chemotherapy, and after completion of chemotherapy. The results of the interpretation of the interviews were formulated in the form of 3 themes: (1) feeling the same despite radical castrating surgery, (2) accepting chemotherapy, and (3) maintaining normality and support. Suggestions of caring implications from our interpretation of the interview data underscore the need to support these women in learning to cope with their feelings of weakness and anxiety. The findings further indicate the potential in narrative methods to identify important issues in comprehensive cancer care.

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.

The importance of maintainability in maintenance cost management

International Nuclear Information System (INIS)

Allen, R.R.

1996-01-01

This paper provides specific examples and results from ongoing projects at Power Plants, and for offshore oil platforms. The paper describes the vital role maintainability has on plant availability. How the application of equipment maintainability principles, if addressed using state of the art computer tools and advanced business processes can bring annual return on investment results as high as 15 to 1. The maintenance process of today and for the future must provide for high plant availability at the lowest possible cost. The high cost of obtaining equipment reliability levels necessary to meet required availability demands has not proved to be sustainable. Therefore new business decision processes that address equipment failures as part of the maintenance process have been developed. Repair costs require that equipment failures be selective and controlled so that a high level of safety and plant availability is assurance. This can only be accomplished by the use of advanced computer tools in the hands of well trained maintenance-engineering specialist. The relationship between Reliability Centered Maintenance (RCM), Condition Directed Planned Maintenance (CDPM), and maintainability is also presented

Reliability and mechanical design

International Nuclear Information System (INIS)

Lemaire, Maurice

1997-01-01

A lot of results in mechanical design are obtained from a modelisation of physical reality and from a numerical solution which would lead to the evaluation of needs and resources. The goal of the reliability analysis is to evaluate the confidence which it is possible to grant to the chosen design through the calculation of a probability of failure linked to the retained scenario. Two types of analysis are proposed: the sensitivity analysis and the reliability analysis. Approximate methods are applicable to problems related to reliability, availability, maintainability and safety (RAMS)

A feasible, aesthetic quality evaluation of implant-supported single crowns: an analysis of validity and reliability

DEFF Research Database (Denmark)

Hosseini, Mandana; Gotfredsen, Klaus

2012-01-01

OBJECTIVES: To test the reliability and validity of six aesthetic parameters and to compare the professional- and patient-reported aesthetic outcomes. MATERIAL AND METHODS: Thirty-four patients with 66 implant-supported premolar crowns were included. Two prosthodontists and 11 dental students......,24) were found between patient and professional evaluations. CONCLUSIONS: The feasibility, reliability and validity of the CIS make the parameters useful for quality control of implant-supported restorations. The professional- and patient-reported aesthetic outcomes had no significant correlation....... and the internal consistency were analysed by Cohen's ¿ and Cronbach's a, respectively. The validity of CIS parameters was tested against the corresponding Visual Analogue Scales (VAS) scores. The Spearman correlation coefficients were used. Six aesthetic Oral Health Impact Profile (OHIP) questions were correlated...

Seismic reliability assessment of RC structures including soil–structure interaction using wavelet weighted least squares support vector machine

International Nuclear Information System (INIS)

Khatibinia, Mohsen; Javad Fadaee, Mohammad; Salajegheh, Javad; Salajegheh, Eysa

2013-01-01

An efficient metamodeling framework in conjunction with the Monte-Carlo Simulation (MCS) is introduced to reduce the computational cost in seismic reliability assessment of existing RC structures. In order to achieve this purpose, the metamodel is designed by combining weighted least squares support vector machine (WLS-SVM) and a wavelet kernel function, called wavelet weighted least squares support vector machine (WWLS-SVM). In this study, the seismic reliability assessment of existing RC structures with consideration of soil–structure interaction (SSI) effects is investigated in accordance with Performance-Based Design (PBD). This study aims to incorporate the acceptable performance levels of PBD into reliability theory for comparing the obtained annual probability of non-performance with the target values for each performance level. The MCS method as the most reliable method is utilized to estimate the annual probability of failure associated with a given performance level in this study. In WWLS-SVM-based MCS, the structural seismic responses are accurately predicted by WWLS-SVM for reducing the computational cost. To show the efficiency and robustness of the proposed metamodel, two RC structures are studied. Numerical results demonstrate the efficiency and computational advantages of the proposed metamodel for the seismic reliability assessment of structures. Furthermore, the consideration of the SSI effects in the seismic reliability assessment of existing RC structures is compared to the fixed base model. It shows which SSI has the significant influence on the seismic reliability assessment of structures.

Availability, reliability and logistic support studies of the RF power system design options for the IFMIF accelerator

Energy Technology Data Exchange (ETDEWEB)

Bargallo, E., E-mail: enric.bargallo-font@upc.edu [Fusion Energy Engineering Laboratory (FEEL), Technical University of Catalonia (UPC) Barcelona-Tech, Barcelona (Spain); Giralt, A.; Martinez, G. [Fusion Energy Engineering Laboratory (FEEL), Technical University of Catalonia (UPC) Barcelona-Tech, Barcelona (Spain); Weber, M.; Regidor, D.; Arroyo, J.M. [Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas, Madrid (Spain); Abal, J.; Dies, J.; Tapia, C.; De Blas, A. [Fusion Energy Engineering Laboratory (FEEL), Technical University of Catalonia (UPC) Barcelona-Tech, Barcelona (Spain); Mendez, P.; Ibarra, A.; Molla, J. [Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas, Madrid (Spain)

2013-10-15

Highlights: ► Current RF system design based on tetrodes chains is evaluated. ► Alternative solid state power amplifiers RF system design is analyzed. ► Both designs are compared in terms of availability, logistics and cost. ► It is concluded that solid state option presents relevant improvements. -- Abstract: The current design of the radio frequency (RF) power system for the International Fusion Materials Irradiation Facility (IFMIF) is based upon tetrodes technology. Due to the improvement in the solid state amplifiers technology, the possibility of using this option for IFMIF RF system is becoming a very competitive alternative presenting from the beginning several advantages in terms of availability, reliability and logistics. The current design based on RF tetrodes chains leads no room for substantial improvements in terms of availability being the requirement for the RF system hard to achieve. The principal goals of this paper are to use RAMI (Reliability, Availability, Maintainability and Inspectionability) analysis in the solid state amplifier design, and to compare the availability, reliability and logistic performances for both alternatives.

Availability, reliability and logistic support studies of the RF power system design options for the IFMIF accelerator

International Nuclear Information System (INIS)

Bargallo, E.; Giralt, A.; Martinez, G.; Weber, M.; Regidor, D.; Arroyo, J.M.; Abal, J.; Dies, J.; Tapia, C.; De Blas, A.; Mendez, P.; Ibarra, A.; Molla, J.

2013-01-01

Highlights: ► Current RF system design based on tetrodes chains is evaluated. ► Alternative solid state power amplifiers RF system design is analyzed. ► Both designs are compared in terms of availability, logistics and cost. ► It is concluded that solid state option presents relevant improvements. -- Abstract: The current design of the radio frequency (RF) power system for the International Fusion Materials Irradiation Facility (IFMIF) is based upon tetrodes technology. Due to the improvement in the solid state amplifiers technology, the possibility of using this option for IFMIF RF system is becoming a very competitive alternative presenting from the beginning several advantages in terms of availability, reliability and logistics. The current design based on RF tetrodes chains leads no room for substantial improvements in terms of availability being the requirement for the RF system hard to achieve. The principal goals of this paper are to use RAMI (Reliability, Availability, Maintainability and Inspectionability) analysis in the solid state amplifier design, and to compare the availability, reliability and logistic performances for both alternatives

A fast method for calculating reliable event supports in tree reconciliations via Pareto optimality.

Science.gov (United States)

To, Thu-Hien; Jacox, Edwin; Ranwez, Vincent; Scornavacca, Celine

2015-11-14

Given a gene and a species tree, reconciliation methods attempt to retrieve the macro-evolutionary events that best explain the discrepancies between the two tree topologies. The DTL parsimonious approach searches for a most parsimonious reconciliation between a gene tree and a (dated) species tree, considering four possible macro-evolutionary events (speciation, duplication, transfer, and loss) with specific costs. Unfortunately, many events are erroneously predicted due to errors in the input trees, inappropriate input cost values or because of the existence of several equally parsimonious scenarios. It is thus crucial to provide a measure of the reliability for predicted events. It has been recently proposed that the reliability of an event can be estimated via its frequency in the set of most parsimonious reconciliations obtained using a variety of reasonable input cost vectors. To compute such a support, a straightforward but time-consuming approach is to generate the costs slightly departing from the original ones, independently compute the set of all most parsimonious reconciliations for each vector, and combine these sets a posteriori. Another proposed approach uses Pareto-optimality to partition cost values into regions which induce reconciliations with the same number of DTL events. The support of an event is then defined as its frequency in the set of regions. However, often, the number of regions is not large enough to provide reliable supports. We present here a method to compute efficiently event supports via a polynomial-sized graph, which can represent all reconciliations for several different costs. Moreover, two methods are proposed to take into account alternative input costs: either explicitly providing an input cost range or allowing a tolerance for the over cost of a reconciliation. Our methods are faster than the region based method, substantially faster than the sampling-costs approach, and have a higher event-prediction accuracy on

Reliability of a Novel Social Activity Questionnaire: Perceived Social Support and Verbal Interaction in the Wisconsin Registry for Alzheimer's Prevention.

Science.gov (United States)

Zuelsdorff, Megan L; Koscik, Rebecca L; Okonkwo, Ozioma C; Peppard, Paul E; Hermann, Bruce P; Sager, Mark A; Johnson, Sterling C; Engelman, Corinne D

2018-02-01

Social activity is associated with healthy aging and preserved cognition. Such activity includes a confluence of social support and verbal interaction, each influencing cognition through rarely parsed, mechanistically distinct pathways. We created a novel verbal interaction measure for the Wisconsin Registry for Alzheimer's Prevention (WRAP) and assessed reliability of resultant data, a first step toward mechanism-driven examination of social activity as a modifiable predictor of cognitive health. Two WRAP subsamples completed a test-retest study to determine 8-week stability ( n = 107) and 2-year stability ( n = 136) of verbal interaction, and 2-year stability of perceived social support. Reliability was determined using quadratic-weighted kappa, percent agreement, or correlation coefficients. Reliability was fair to almost perfect. The association between social support and interaction quantity decreased with age. Social activity data demonstrate moderate to excellent temporal stability. Moreover, in older individuals, social support and verbal interaction represent two distinct dimensions of social activity.

Development of KSC program for investigating and generating field failure rates. Reliability handbook for ground support equipment

Science.gov (United States)

Bloomquist, C. E.; Kallmeyer, R. H.

1972-01-01

Field failure rates and confidence factors are presented for 88 identifiable components of the ground support equipment at the John F. Kennedy Space Center. For most of these, supplementary information regarding failure mode and cause is tabulated. Complete reliability assessments are included for three systems, eight subsystems, and nine generic piece-part classifications. Procedures for updating or augmenting the reliability results are also included.

Maintaining steam/condensate lines

International Nuclear Information System (INIS)

Russum, S.A.

1992-01-01

Steam and condensate systems must be maintained with the same diligence as the boiler itself. Unfortunately, they often are not. The water treatment program, critical to keeping the boiler at peak efficiency and optimizing operating life, should not stop with the boiler. The program must encompass the steam and condensate system as well. A properly maintained condensate system maximizes condensate recovery, which is a cost-free energy source. The fuel needed to turn the boiler feedwater into steam has already been provided. Returning the condensate allows a significant portion of that fuel cost to be recouped. Condensate has a high heat content. Condensate is a readily available, economical feedwater source. Properly treated, it is very pure. Condensate improves feedwater quality and reduces makeup water demand and pretreatment costs. Higher quality feedwater means more reliable boiler operation

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

A Vision for Spaceflight Reliability: NASA's Objectives Based Strategy

Science.gov (United States)

Groen, Frank; Evans, John; Hall, Tony

2015-01-01

In defining the direction for a new Reliability and Maintainability standard, OSMA has extracted the essential objectives that our programs need, to undertake a reliable mission. These objectives have been structured to lead mission planning through construction of an objective hierarchy, which defines the critical approaches for achieving high reliability and maintainability (R M). Creating a hierarchy, as a basis for assurance implementation, is a proven approach; yet, it holds the opportunity to enable new directions, as NASA moves forward in tackling the challenges of space exploration.

Validity and reliability of the Malay version multidimensional scale of perceived social support (MSPSS-M) among teachers.

Science.gov (United States)

Lee, Soo Cheng; Moy, Foong Ming; Hairi, Noran Naqiah

2017-01-01

The multidimensional scale of perceived social support (MSPSS) was developed to measure perceived social support. It has been translated and culturally adapted among natives literate in the Malay language. However, its psychometric properties for teachers who are majority females and married have not been assessed. This was a cross-sectional study conducted among the public secondary school teachers in the central region of Peninsular Malaysia from May to July 2013. A total of 150 and 203 teachers were recruited to perform exploratory factor analysis and confirmatory factor analysis (CFA), respectively. Reliability testing was evaluated on 141 teachers via internal consistency and two-week interval test-retest. The 12-item three-factor structure of MSPSS-M was revised to 8-item two-factor structure. The revised MSPSS-M demonstrated excellent fit in CFA with adequate divergent and convergent validity and good factor loadings (0.80-0.90). The revised MSPSS-M also displayed good internal consistency with Cronbach's alpha of 0.91, 0.93 and 0.92 and good test-retest reliability with intraclass correlation of 0.89, 0.88 and 0.88 in the total scale, family and friends factors, respectively. The revised 8-item MSPSS-M is a reliable and valid tool for assessment of perceived social support among teachers.

Human factor reliability program

International Nuclear Information System (INIS)

Knoblochova, L.

2017-01-01

The human factor's reliability program was at Slovenske elektrarne, a.s. (SE) nuclear power plants. introduced as one of the components Initiatives of Excellent Performance in 2011. The initiative's goal was to increase the reliability of both people and facilities, in response to 3 major areas of improvement - Need for improvement of the results, Troubleshooting support, Supporting the achievement of the company's goals. The human agent's reliability program is in practice included: - Tools to prevent human error; - Managerial observation and coaching; - Human factor analysis; -Quick information about the event with a human agent; -Human reliability timeline and performance indicators; - Basic, periodic and extraordinary training in human factor reliability(authors)

Winning public and political support for nuclear

International Nuclear Information System (INIS)

McFadden, D.J.

2006-01-01

The nuclear industry is entering an historic battle for the hearts and minds of Canadians as government decides on nuclear new build. Recent polls indicate that public support is rising for nuclear power. However, the support could be eroded by negative events or intense lobbying by anti-nuclear groups. The nuclear industry must deal with concerns raised about nuclear power, such as cost, safety, reliability and waste. The nuclear industry should build upon the positive movement in public support. The industry must go to Canadians with a credible message which responds effectively to public concerns. It must be remembered that winning public support will be essential to winning and maintaining political support. (author)

Winning public and political support for nuclear

Energy Technology Data Exchange (ETDEWEB)

McFadden, D.J. [Gowling LaFleur Henderson, LLP, Toronto, Ontario (Canada)

2006-07-01

The nuclear industry is entering an historic battle for the hearts and minds of Canadians as government decides on nuclear new build. Recent polls indicate that public support is rising for nuclear power. However, the support could be eroded by negative events or intense lobbying by anti-nuclear groups. The nuclear industry must deal with concerns raised about nuclear power, such as cost, safety, reliability and waste. The nuclear industry should build upon the positive movement in public support. The industry must go to Canadians with a credible message which responds effectively to public concerns. It must be remembered that winning public support will be essential to winning and maintaining political support. (author)

Integrated approach for combining sustainability and safety into a RAM analysis, RAM2S (Reliability, Availability, Maintainability, Sustainability and Safety) towards greenhouse gases emission targets

Energy Technology Data Exchange (ETDEWEB)

Alvarenga, Tobias V. [Det Norske Veritas (DNV), Hovik, Oslo (Norway)

2009-07-01

This paper aims to present an approach to integrate sustainability and safety concerns on top of a typical RAM Analysis to support new enterprises to find alternatives to align themselves to the greenhouse gases emission targets, measured as CO{sub 2} (carbon dioxide) equivalent. This approach can be used to measure the impact of the potential CO{sub 2} equivalent emission levels mainly related to new enterprises with high CO{sub 2} content towards environment and production, as per example, the extraction of oil and gas from the Brazilian Pre-salt layers. In this sense, this integrated approach, combining Sustainability and Safety into a RAM analysis, RAM2S (Reliability, Availability, Maintainability, Sustainability and Safety), can be used to assess the impact of CO{sub 2} 'production' along the entire enterprise life-cycle, including the impact of possible facility shutdown due to emission restrictions limits, as well as due to the occurrence of additional failures modes related to CO{sub 2} corrosion capabilities. Thus, at the end, this integrated approach would allow companies to find out a more cost-effective alternative to adapt their business into the global warming reality, overcoming the inherent threats of greenhouse gases. (author)

Plans for Assessing Contractor Performance for the Camp Lemonnier Base Operations Support Contract Needed Improvement

Science.gov (United States)

2015-08-27

electrical power such that all electrical requirements are continually met. 18. Wastewater : Operate and maintain the wastewater treatment plant and...supply—in our review. Roles and Responsibilities NAVFAC provides public works support for U.S. Naval shore installations around the world , and, as...Electrical: Operate and maintain the electrical power generation plant and distribution system to safely produce, transmit, and distribute reliable

The new Space Shuttle Transportation System (STS) - Problem, performance, supportability, and programmatic trending program

Science.gov (United States)

Crawford, J. L.; Rodney, G. A.

1989-01-01

This paper describes the NASA Space Shuttle Trend Analysis program. The four main areas of the program - problem/reliability, performance, supportability, and programmatic trending - are defined, along with motivation for these areas, the statistical methods used, and illustrative Space Shuttle applications. Also described is the NASA Safety, Reliability, Maintainability and Quality Assurance (SRM&QA) Management Information Center, used to focus management attention on key near-term launch concerns and long-range mission trend issues. Finally, the computer data bases used to support the program and future program enhancements are discussed.

Product manufacturing, quality, and reliability initiatives to maintain a competitive advantage and meet customer expectations in the semiconductor industry

Science.gov (United States)

Capps, Gregory

Semiconductor products are manufactured and consumed across the world. The semiconductor industry is constantly striving to manufacture products with greater performance, improved efficiency, less energy consumption, smaller feature sizes, thinner gate oxides, and faster speeds. Customers have pushed towards zero defects and require a more reliable, higher quality product than ever before. Manufacturers are required to improve yields, reduce operating costs, and increase revenue to maintain a competitive advantage. Opportunities exist for integrated circuit (IC) customers and manufacturers to work together and independently to reduce costs, eliminate waste, reduce defects, reduce warranty returns, and improve quality. This project focuses on electrical over-stress (EOS) and re-test okay (RTOK), two top failure return mechanisms, which both make great defect reduction opportunities in customer-manufacturer relationship. Proactive continuous improvement initiatives and methodologies are addressed with emphasis on product life cycle, manufacturing processes, test, statistical process control (SPC), industry best practices, customer education, and customer-manufacturer interaction.

Reliability of the Alzheimer's disease assessment scale (ADAS-Cog) in longitudinal studies.

Science.gov (United States)

Khan, Anzalee; Yavorsky, Christian; DiClemente, Guillermo; Opler, Mark; Liechti, Stacy; Rothman, Brian; Jovic, Sofija

2013-11-01

Considering the scarcity of longitudinal assessments of reliability, there is need for a more precise understanding of cognitive decline in Alzheimer's Disease (AD). The primary goal was to assess longitudinal changes in inter-rater reliability, test retest reliability and internal consistency of scores of the ADAS-Cog. 2,618 AD subjects were enrolled in seven randomized, double-blind, placebo-controlled, multicenter-trials from 1986 to 2009. Reliability, internal-consistency and cross-sectional analysis of ADAS-Cog and MMSE across seven visits were examined. Intra-class correlation (ICC) for ADAS-Cog was moderate to high supporting their reliability. Absolute Agreement ICCs 0.392 (Visit-7) to 0.806 (Visit-2) showed a progressive decrease in correlations across time. Item analysis revealed a decrease in item correlations, with the lowest correlations for Visit 7 for Commands (ICC=0.148), Comprehension (ICC=0.092), Spoken Language (ICC=0.044). Suitable assessment of AD treatments is maintained through accurate measurement of clinically significant outcomes. Targeted rater education ADAS-Cog items over-time can improve ability to administer and score the scale.

Accelerator Availability and Reliability Issues

Energy Technology Data Exchange (ETDEWEB)

Steve Suhring

2003-05-01

Maintaining reliable machine operations for existing machines as well as planning for future machines' operability present significant challenges to those responsible for system performance and improvement. Changes to machine requirements and beam specifications often reduce overall machine availability in an effort to meet user needs. Accelerator reliability issues from around the world will be presented, followed by a discussion of the major factors influencing machine availability.

76 FR 73608 - Reliability Technical Conference, North American Electric Reliability Corporation, Public Service...

Science.gov (United States)

2011-11-29

... or municipal authority play in forming your bulk power system reliability plans? b. Do you support..., North American Electric Reliability Corporation (NERC) Nick Akins, CEO of American Electric Power (AEP..., EL11-62-000] Reliability Technical Conference, North American Electric Reliability Corporation, Public...

Effect of Diamondlike Carbon Coating on Reliability of Implant-Supported Crowns.

Science.gov (United States)

Hirata, Ronaldo; Machado, Lucas Silveira; Bonfante, Estevam A; Yamaguchi, Satoshi; Imazato, Satoshi; Coelho, Paulo G

2015-01-01

To evaluate the effect of diamondlike carbon (DLC) coating on abutments and/or abutment screws on the reliability, characteristic strength, and Weibull modulus of implant-supported single crowns. Seventy-two external hexagon implants (Emfills Implant 4 mm diameter, 10 mm length, Emfills) were divided into four groups (n = 18 each), according to the presence or not of a DLC coating in the abutment and/or abutment screw, as follows: abutment without coating, screw without coating (AwcSwc); abutment without coating with coated screw (AwcSC); abutment coated with noncoated screw (ACSwc), and coated abutment with coated screw (ACSC). Abutments and screws were evaluated with scanning electron microscopy. The specimens were subjected to step-stress accelerated life testing in water. Use-level probability Weibull curves and reliability for a mission of 100,000 cycles at 150 N (90% two-sided confidence intervals) were calculated. Polarized light and scanning electron microscopes were used for fractographic analysis. For a mission of 100,000 cycles at 150 N, reliability was 0.45 (0.20 to 0.67), 0.12 (0.00 to 0.47), 0.56 (0.17 to 0.82), and 0.44 (0.07 to 0.77) for AwcSwc, AwcSC, ACSwc, and ACSC, respectively. The probability Weibull calculation showed a Weibull modulus (m) of m = 5.50, m = 11.64, m = 16.96, and m = 15.08 and the characteristic strengths (η, which indicates the load at which 63.2% of the specimens of each group fail) of η = 202.67 N, ŋ = 206.64 N, ŋ = 192.54 N, and ŋ = 203.59 N for AwcSwc, AwcSC, ACSwc, and ACSC, respectively. Abutment screw fracture was the chief failure outcome in all groups. Characteristic strength values were not different among groups; neither was reliability. However, an increase in Weibull modulus (indicating low variability of the results) was observed with DLC coating of abutment or screw or both.

Reliability of Power Electronic Converter Systems

DEFF Research Database (Denmark)

-link capacitance in power electronic converter systems; wind turbine systems; smart control strategies for improved reliability of power electronics system; lifetime modelling; power module lifetime test and state monitoring; tools for performance and reliability analysis of power electronics systems; fault...... for advancing the reliability, availability, system robustness, and maintainability of PECS at different levels of complexity. Drawing on the experience of an international team of experts, this book explores the reliability of PECS covering topics including an introduction to reliability engineering in power...... electronic converter systems; anomaly detection and remaining-life prediction for power electronics; reliability of DC-link capacitors in power electronic converters; reliability of power electronics packaging; modeling for life-time prediction of power semiconductor modules; minimization of DC...

Work accommodations and natural supports for maintaining employment.

Science.gov (United States)

Corbière, Marc; Villotti, Patrizia; Lecomte, Tania; Bond, Gary R; Lesage, Alain; Goldner, Elliot M

2014-06-01

Job tenure for people with severe mental disorders, even for those enrolled in supported employment programs, is typically brief. Few studies to date have investigated the relationship between accommodations and natural supports available in the workplace, and job tenure for this population. The main objectives of this study were to develop and to validate a new measure to describe work accommodations and natural supports available in the workplace and to determine which of them are significantly related to job tenure for participants enrolled in supported employment services. In total, 124 people with a severe mental disorder enrolled in supported employment programs and who obtained only one competitive employment at the 9-month follow-up answered the Work Accommodation and Natural Support Scale (WANSS). They also provided information regarding their disclosure (or non-) of mental disorders in the workplace and the length of their job tenure. Confirmatory factor analysis conducted on the WANSS showed 40 items distributed on 6 dimensions (e.g., Schedule flexibility). Correlation results showed that disclosure was significantly related to the number of work accommodations and natural supports available in the workplace. Survival analyses indicated that one WANSS dimension was more salient in predicting job tenure: Supervisor and coworker supports. The WANSS is a valid and useful tool to assess work accommodations and natural supports available in the workplace that employment specialists could use in their practice.

Improving the Reliability of Decision-Support Systems for Nuclear Emergency Management by Leveraging Software Design Diversity

Directory of Open Access Journals (Sweden)

Tudor B. Ionescu

2016-03-01

Full Text Available This paper introduces a novel method of continuous verification of simulation software used in decision-support systems for nuclear emergency management (DSNE. The proposed approach builds on methods from the field of software reliability engineering, such as N-Version Programming, Recovery Blocks, and Consensus Recovery Blocks. We introduce a new acceptance test for dispersion simulation results and a new voting scheme based on taxonomies of simulation results rather than individual simulation results. The acceptance test and the voter are used in a new scheme, which extends the Consensus Recovery Block method by a database of result taxonomies to support machine-learning. This enables the system to learn how to distinguish correct from incorrect results, with respect to the implemented numerical schemes. Considering that decision-support systems for nuclear emergency management are used in a safety-critical application context, the methods introduced in this paper help improve the reliability of the system and the trustworthiness of the simulation results used by emergency managers in the decision making process. The effectiveness of the approach has been assessed using the atmospheric dispersion forecasts of two test versions of the widely used RODOS DSNE system.

Towards Reliable Integrated Services for Dependable Systems

DEFF Research Database (Denmark)

Schiøler, Henrik; Ravn, Anders Peter; Izadi-Zamanabadi, Roozbeh

Reliability issues for various technical systems are discussed and focus is directed towards distributed systems, where communication facilities are vital to maintain system functionality. Reliability in communication subsystems is considered as a resource to be shared among a number of logical c...... applications residing on alternative routes. Details are provided for the operation of RRRSVP based on reliability slack calculus. Conclusions summarize the considerations and give directions for future research....... connections and a reliability management framework is suggested. We suggest a network layer level reliability management protocol RRSVP (Reliability Resource Reservation Protocol) as a counterpart of the RSVP for bandwidth and time resource management. Active and passive standby redundancy by background...

Towards Reliable Integrated Services for Dependable Systems

DEFF Research Database (Denmark)

Schiøler, Henrik; Ravn, Anders Peter; Izadi-Zamanabadi, Roozbeh

2003-01-01

Reliability issues for various technical systems are discussed and focus is directed towards distributed systems, where communication facilities are vital to maintain system functionality. Reliability in communication subsystems is considered as a resource to be shared among a number of logical c...... applications residing on alternative routes. Details are provided for the operation of RRRSVP based on reliability slack calculus. Conclusions summarize the considerations and give directions for future research....... connections and a reliability management framework is suggested. We suggest a network layer level reliability management protocol RRSVP (Reliability Resource Reservation Protocol) as a counterpart of the RSVP for bandwidth and time resource management. Active and passive standby redundancy by background...

Maintenance optimization plan for essential equipment reliability

International Nuclear Information System (INIS)

Steffen, D.H.

1996-02-01

The Maintenance Optimization Plan (MOP) for Essential Equipment Reliability will furnish Tank Waste Remediation System (TWRS) management with a pro-active, forward-thinking process for maintaining essential structures, systems, and components (ESSC) at the Hanford Site tank farms in their designed condition, and to ensure optimum ESSC availability and reliability

Reliability evaluation of power systems

CERN Document Server

Billinton, Roy

1996-01-01

The Second Edition of this well-received textbook presents over a decade of new research in power system reliability-while maintaining the general concept, structure, and style of the original volume. This edition features new chapters on the growing areas of Monte Carlo simulation and reliability economics. In addition, chapters cover the latest developments in techniques and their application to real problems. The text also explores the progress occurring in the structure, planning, and operation of real power systems due to changing ownership, regulation, and access. This work serves as a companion volume to Reliability Evaluation of Engineering Systems: Second Edition (1992).

Reliability and Validity of the Multidimensional Scale of Perceived Social Support (MSPSS): Thai Version.

Science.gov (United States)

Wongpakaran, Tinakon; Wongpakaran, Nahathai; Ruktrakul, Ruk

2011-01-01

This study examines the Thai version of the Multidimensional Scale of Perceived Social Support (MSPSS) for its psychometric properties. In total 462 participants were recruited - 310 medical students from Chiang Mai University and 152 psychiatric patients, and they completed the Thai version of the MSPSS, the State Trait Anxiety Inventory (STAI), the Rosenberg Self-Esteem Scale (RSES) and the Thai Depression Inventory (TDI). Test-retest reliability was conducted over a four week period. Factor analysis produced three-factor solutions for both patient (PG) and student groups (SG), and overall the model demonstrated adequate fit indices. The mean total score and the sub-scale score for the SG were statistically higher than those in the PG, except for 'Significant Others'. The internal consistency of the scale was good, with a Cronbach's alpha of 0.91 for the SG and 0.87 for the PG. After a four week retest for reliability exercise, the intra-class correlation coefficient (ICC) was found to be 0.84. The Thai-MSPSS was found to have a negative correlation with the STAI and the TDI, but was positively correlated with the RSES. The Thai MSPSS is a reliable and valid instrument to use.

A dynamic particle filter-support vector regression method for reliability prediction

International Nuclear Information System (INIS)

Wei, Zhao; Tao, Tao; ZhuoShu, Ding; Zio, Enrico

2013-01-01

Support vector regression (SVR) has been applied to time series prediction and some works have demonstrated the feasibility of its use to forecast system reliability. For accuracy of reliability forecasting, the selection of SVR's parameters is important. The existing research works on SVR's parameters selection divide the example dataset into training and test subsets, and tune the parameters on the training data. However, these fixed parameters can lead to poor prediction capabilities if the data of the test subset differ significantly from those of training. Differently, the novel method proposed in this paper uses particle filtering to estimate the SVR model parameters according to the whole measurement sequence up to the last observation instance. By treating the SVR training model as the observation equation of a particle filter, our method allows updating the SVR model parameters dynamically when a new observation comes. Because of the adaptability of the parameters to dynamic data pattern, the new PF–SVR method has superior prediction performance over that of standard SVR. Four application results show that PF–SVR is more robust than SVR to the decrease of the number of training data and the change of initial SVR parameter values. Also, even if there are trends in the test data different from those in the training data, the method can capture the changes, correct the SVR parameters and obtain good predictions. -- Highlights: •A dynamic PF–SVR method is proposed to predict the system reliability. •The method can adjust the SVR parameters according to the change of data. •The method is robust to the size of training data and initial parameter values. •Some cases based on both artificial and real data are studied. •PF–SVR shows superior prediction performance over standard SVR

Columbus safety and reliability

Science.gov (United States)

Longhurst, F.; Wessels, H.

1988-10-01

Analyses carried out to ensure Columbus reliability, availability, and maintainability, and operational and design safety are summarized. Failure modes/effects/criticality is the main qualitative tool used. The main aspects studied are fault tolerance, hazard consequence control, risk minimization, human error effects, restorability, and safe-life design.

Reliability engineering theory and practice

CERN Document Server

Birolini, Alessandro

2014-01-01

This book shows how to build in, evaluate, and demonstrate reliability and availability of components, equipment, systems. It presents the state-of-theart of reliability engineering, both in theory and practice, and is based on the author's more than 30 years experience in this field, half in industry and half as Professor of Reliability Engineering at the ETH, Zurich. The structure of the book allows rapid access to practical results. This final edition extend and replace all previous editions. New are, in particular, a strategy to mitigate incomplete coverage, a comprehensive introduction to human reliability with design guidelines and new models, and a refinement of reliability allocation, design guidelines for maintainability, and concepts related to regenerative stochastic processes. The set of problems for homework has been extended. Methods & tools are given in a way that they can be tailored to cover different reliability requirement levels and be used for safety analysis. Because of the Appendice...

Preventive maintenance and reliability-centered maintenance

International Nuclear Information System (INIS)

Anderson, J.G.

1989-01-01

In the recent past, the primary function of the preventive maintenance program at a nuclear power plant was to maintain the operability and reliability of the plant. Reducing overall maintenance costs by performing effective preventive maintenance, instead of more costly and disruptive corrective maintenance, instead of more costly and disruptive corrective maintenance, was a secondary consideration. In today's operating environment, the preventive maintenance program must meet the test of cost-effectiveness as well as many new standards for performance that are being required by rate regulators. The preventive maintenance program must be able to withstand the challenge of independent audit to a new standard of technical adequacy and compliance with recommendations from component vendors. In this new environment, the standard that is being applied at the San Onofre nuclear generating station (SONGS) is that the preventive maintenance program must meet the test of cost-effectiveness, improve equipment performance, support increased plant availability, and (a) literally implement the recommendations of the vendor, (b) provide other compensation for the vendor recommendation, or (c) provide technical justification for the deviation. The subject of this paper is the way that reliability-centered maintenance (RCM) is helping SONGS meet these challenges

Operations and support cost modeling of conceptual space vehicles

Science.gov (United States)

Ebeling, Charles

1994-01-01

The University of Dayton is pleased to submit this annual report to the National Aeronautics and Space Administration (NASA) Langley Research Center which documents the development of an operations and support (O&S) cost model as part of a larger life cycle cost (LCC) structure. It is intended for use during the conceptual design of new launch vehicles and spacecraft. This research is being conducted under NASA Research Grant NAG-1-1327. This research effort changes the focus from that of the first two years in which a reliability and maintainability model was developed to the initial development of an operations and support life cycle cost model. Cost categories were initially patterned after NASA's three axis work breakdown structure consisting of a configuration axis (vehicle), a function axis, and a cost axis. A revised cost element structure (CES), which is currently under study by NASA, was used to established the basic cost elements used in the model. While the focus of the effort was on operations and maintenance costs and other recurring costs, the computerized model allowed for other cost categories such as RDT&E and production costs to be addressed. Secondary tasks performed concurrent with the development of the costing model included support and upgrades to the reliability and maintainability (R&M) model. The primary result of the current research has been a methodology and a computer implementation of the methodology to provide for timely operations and support cost analysis during the conceptual design activities.

Reliability analysis of stiff versus flexible piping

International Nuclear Information System (INIS)

Lu, S.C.

1985-01-01

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

Designing reliability into accelerators

International Nuclear Information System (INIS)

Hutton, A.

1992-08-01

For the next generation of high performance, high average luminosity colliders, the ''factories,'' reliability engineering must be introduced right at the inception of the project and maintained as a central theme throughout the project. There are several aspects which will be addressed separately: Concept; design; motivation; management techniques; and fault diagnosis

Reliability based structural design

NARCIS (Netherlands)

Vrouwenvelder, A.C.W.M.

2014-01-01

According to ISO 2394, structures shall be designed, constructed and maintained in such a way that they are suited for their use during the design working life in an economic way. To fulfil this requirement one needs insight into the risk and reliability under expected and non-expected actions. A

Reliability of power electronic converter systems

CERN Document Server

Chung, Henry Shu-hung; Blaabjerg, Frede; Pecht, Michael

2016-01-01

This book outlines current research into the scientific modeling, experimentation, and remedial measures for advancing the reliability, availability, system robustness, and maintainability of Power Electronic Converter Systems (PECS) at different levels of complexity.

An assessment of maintainability of elevator system to improve facilities management knowledge-base

Science.gov (United States)

Siti, N. A.; Asmone, A. S.; Chew, M. Y. L.

2018-02-01

Elevator system is a highly specialized machinery that requires technicians that have a wider array of knowledge in maintaining the system to be safe and reliable. While attaining reliable data of elevator malfunction become challenges, this study has filled the gap by gathering the management-maintenance issues and operational defects of elevator system. Forty-three types of operation defects were found and the consequence defects and their possible causes of occurrences were discussed. To respond to the prime challenges of maintaining elevator system provided by the industry players’ perspective, a theoretical framework is established as a recommendation to improve knowledge base of defects in elevator system which comprises good practices, and solutions to rectify each defects found. Hence, this research paper has theoretically improved the knowledge base of maintainability of elevator system and provide meaningful guidelines in practical senses to the industry professionals.

Reliability Analysis of RSG-GAS Primary Cooling System to Support Aging Management Program

Science.gov (United States)

Deswandri; Subekti, M.; Sunaryo, Geni Rina

2018-02-01

Multipurpose Research Reactor G.A. Siwabessy (RSG-GAS) which has been operating since 1987 is one of the main facilities on supporting research, development and application of nuclear energy programs in BATAN. Until now, the RSG-GAS research reactor has been successfully operated safely and securely. However, because it has been operating for nearly 30 years, the structures, systems and components (SSCs) from the reactor would have started experiencing an aging phase. The process of aging certainly causes a decrease in reliability and safe performances of the reactor, therefore the aging management program is needed to resolve the issues. One of the programs in the aging management is to evaluate the safety and reliability of the system and also screening the critical components to be managed.One method that can be used for such purposes is the Fault Tree Analysis (FTA). In this papers FTA method is used to screening the critical components in the RSG-GAS Primary Cooling System. The evaluation results showed that the primary isolation valves are the basic events which are dominant against the system failure.

78 FR 58492 - Generator Verification Reliability Standards

Science.gov (United States)

2013-09-24

... power capability that is available for planning models and bulk electric system reliability assessments... of generator equipment needed to support Bulk-Power System reliability and enhance coordination of... support Bulk-Power System reliability and will ensure that accurate data is verified and made available...

The Reliability of Turkish "Basic Life Support" and "Cardiac Massage" Videos Uploaded to Websites.

Science.gov (United States)

Elicabuk, Hayri; Yaylacı, Serpil; Yilmaz, Atakan; Hatipoglu, Celile; Kaya, F Gokhan; Serinken, Mustafa

2016-02-01

In this study, the reliability of Turkish cardiac massage and Basic Life Support (BLS) videos, which have already been downloaded from three website such as YouTube, Google, Yahoo following the publication of 2010 cardiopulmonary resuscitation (CPR) guideline and their suitability to the same guideline were researched. The videos uploaded to the three web-site to search videos on internet were queried by using the keywords "cardiac massage" and "basic life support". Videos that had been uploaded between January 2011 and July 2014 were analyzed and scored by two experienced emergency specialists. A total of 1126 videos were obtained. 1029 of the videos (91.4%) were excluded by researchers. 97 videos were detected to accord with study criteria. Despite most of the videos were found on Google website by keywords, the enormous part of videos proper to criteria were sourced from YouTube website (n=65, 67.0%). One fourth of the videos (24.7%) were observed to not be suitable for 2010 CPR guideline. AED usage was mentioned slightly in the videos (14.4%). Median score of the videos is 5 (IQR: 4-6). The rate and scores of the videos uploaded by official institution or association were significantly higher than others (p=0.007 and 0.006, respectively). Moreover, scores of the videos compatible with guidelines uploaded by official institution or association and medical personal were also found higher (p=0.001). Eventually, all the data obtained in this study support that Turkish videos were not reliable on the subject of BLS and cardiac massage. It is promising that videos with high follow-up rates also have been scored higher.

Engineering systems reliability, safety, and maintenance an integrated approach

CERN Document Server

Dhillon, B S

2017-01-01

Today, engineering systems are an important element of the world economy and each year billions of dollars are spent to develop, manufacture, operate, and maintain various types of engineering systems around the globe. Many of these systems are highly sophisticated and contain millions of parts. For example, a Boeing jumbo 747 is made up of approximately 4.5 million parts including fasteners. Needless to say, reliability, safety, and maintenance of systems such as this have become more important than ever before.　 Global competition and other factors are forcing manufacturers to produce highly reliable, safe, and maintainable engineering products. Therefore, there is a definite need for the reliability, safety, and maintenance professionals to work closely during design and other phases. Engineering Systems Reliability, Safety, and Maintenance: An Integrated Approach eliminates the need to consult many different and diverse sources in the hunt for the information required to design better engineering syste...

Internal consistency reliability and construct validity of the Dutch translation of the Francis Scale of Attitude toward Christianity among adolescents.

Science.gov (United States)

Francis, L J; Hermans, C A

2000-02-01

A sample of 1,021 young people attending Years 7, 8, 9, 10, and 11 at Catholic secondary schools within the state-maintained sector completed the Dutch translation of the Francis Scale of Attitude toward Christianity. The data support its reliability and validity and commend it for further use in studies conducted among young people in The Netherlands.

Modernizing and Maintaining Instrumentation and Control Systems in Nuclear Power Plants

International Nuclear Information System (INIS)

Naser, Joseph; Torok, Raymond; Shankar, Ramesh

2003-01-01

Deregulation of the electric utilities has made a major impact on nuclear power plants. To be competitive, more emphasis is being put on cost-effective production of electricity with a more critical look at whether a system should be modernized due to obsolescence, reliability, or productivity concerns. Instrumentation and control (I and C) systems play an important role in reducing the cost of producing electricity while maintaining or enhancing safety. Systems that are well designed, reliable, enhance productivity, and are cost-effective to operate and maintain can reduce the overall costs. Modern technology with its ability to better provide and use real-time information offers an effective platform for modernizing systems. At the same time, new technology brings new challenges and issues, especially for safety systems in nuclear power plants. To increase competitiveness, it is important to take advantage of the opportunities offered by modern technology and to address the new challenges and issues in a cost-effective manner. The Electric Power Research Institute (EPRI) and its member utilities have been working together with other members of the nuclear industry since 1990 to address I and C modernization and maintenance issues. The EPRI I and C Program has developed a life-cycle management approach for I and C systems that involves the optimization of maintenance, monitoring, and capital resources to sustain safety and performance throughout the plant life. Strategic planning methodologies and implementation guidelines addressing digital I and C issues in nuclear power plants have been developed. Work is ongoing in diverse areas to support the design, implementation, and operation of new digital systems. Technology transfer is an integral part of this I and C program

Challenges of designing fusion reactors for remote maintainability

International Nuclear Information System (INIS)

Mason, L.S.

1981-01-01

One of the major problems faced by the fusion community is the development of the high level of reliability required to assure that fusion will be a viable commercial power source. Much of the responsibility for solving this problem falls directly on the designer in developing concepts that have a high level of maintainability. The problems are both near-term, in developing maintainability for next generation engineering oriented reactors; and long range, in developing full maintainability for the more commercial concepts with their required high level of on-line time. The near-time challenge will include development of unqiue design concepts to perform inspection, maintenance, replacement, and testing under the stringent conditions imposed by the next generation engineering oriented machines. The long range challenge will focus on basic design concepts that will enable the full mainatability required by commerical fusion

Maintaining adequate nutrient supply - Principles, decision-support tools, and best management practices [Chapter 6

Science.gov (United States)

Robert B. Harrison; Douglas A. Maguire; Deborah Page-Dumroese

2011-01-01

Maintaining adequate nutrient supply to maintain or enhance tree vigor and forest growth requires conservation of topsoil and soil organic matter. Sometimes nutrient amendments are also required to supplement inherent nutrient-pool limitations or replenish nutrients removed in harvested material. The goal is to maintain the productive potential of the soil and, when...

QA support for TFTR reliability improvement program in preparation for DT operation

International Nuclear Information System (INIS)

Parsells, R.F.; Howard, H.P.

1987-01-01

As TFTR approaches experiments in the Q=1 regime, machine reliability becomes a major variable in achieving experimental objectives. This paper describes the methods used to quantify current reliability levels, levels required for D-T operations, proposed methods for reliability growth and improvement, and tracking of reliability performance in that growth. Included in this scope are data collection techniques and short comings, bounding current reliability on the upper end, and requirements for D-T operations. Problem characterization through Pareto diagrams provides insight into recurrent failure modes and the use of Duane plots for charting of reliability changes both cumulative and instantaneous, is explained and demonstrated

A reliability program for emergency diesel generators at nuclear power plants: Program structure

International Nuclear Information System (INIS)

Lofgren, E.V.; DeMoss, G.M.; Fragola, J.R.; Appignani, P.L.; Delarche, G.; Boccio, J.

1988-04-01

The purpose of this report is to provide technical guidelines for NRC staff use in the development of positions for evaluating emergency diesel generator (EDG) reliability programs. Such reviews will likely result following resolution of USI A-44 and GSI B-56. The diesel generator reliability program is a management system for achieving and maintaining a selected (or target) level of reliability. This can be achieved by: (1) understanding the factors that control the EDG reliability and (2) then applying reliability and maintenance techniques in the proper proportion to achieve selected performance goals. The concepts and guidelines discussed in this report are concepts and approaches that have been successful in applications where high levels of reliability must be maintained. Both an EDG reliability program process and a set of review items for NRC use are provided. The review items represent a checklist for reviewing EDG reliability programs. They do not, in themselves, constitute a reliability program. Rather, the review items are those distinctive features of a reliability program that must be present for the program to be effective

Using software metrics and software reliability models to attain acceptable quality software for flight and ground support software for avionic systems

Science.gov (United States)

Lawrence, Stella

1992-01-01

This paper is concerned with methods of measuring and developing quality software. Reliable flight and ground support software is a highly important factor in the successful operation of the space shuttle program. Reliability is probably the most important of the characteristics inherent in the concept of 'software quality'. It is the probability of failure free operation of a computer program for a specified time and environment.

An Adaptive Classification Strategy for Reliable Locomotion Mode Recognition

Directory of Open Access Journals (Sweden)

Ming Liu

2017-09-01

Full Text Available Algorithms for locomotion mode recognition (LMR based on surface electromyography and mechanical sensors have recently been developed and could be used for the neural control of powered prosthetic legs. However, the variations in input signals, caused by physical changes at the sensor interface and human physiological changes, may threaten the reliability of these algorithms. This study aimed to investigate the effectiveness of applying adaptive pattern classifiers for LMR. Three adaptive classifiers, i.e., entropy-based adaptation (EBA, LearnIng From Testing data (LIFT, and Transductive Support Vector Machine (TSVM, were compared and offline evaluated using data collected from two able-bodied subjects and one transfemoral amputee. The offline analysis indicated that the adaptive classifier could effectively maintain or restore the performance of the LMR algorithm when gradual signal variations occurred. EBA and LIFT were recommended because of their better performance and higher computational efficiency. Finally, the EBA was implemented for real-time human-in-the-loop prosthesis control. The online evaluation showed that the applied EBA effectively adapted to changes in input signals across sessions and yielded more reliable prosthesis control over time, compared with the LMR without adaptation. The developed novel adaptive strategy may further enhance the reliability of neurally-controlled prosthetic legs.

Resolution of GSI B-56 - Emergency diesel generator reliability

International Nuclear Information System (INIS)

Serkiz, A.W.

1989-01-01

The need for an emergency diesel generator (EDG) reliability program has been established by 10 CFR Part 50, Section 50.63, Loss of All Alternating Current Power, which requires that licensees assess their station blackout coping and recovery capability. EDGs are the principal emergency ac power sources for avoiding a station blackout. Regulatory Guide 1.155, Station Blackout, identifies a need for (1) a nuclear unit EDG reliability level of at least 0.95, and (2) an EDG reliability program to monitor and maintain the required EDG reliability levels. NUMARC-8700, Guidelines and Technical Bases for NUMARC Initiatives Addressing Station Blackout at Light Water Reactors, also provides guidance on such needs. The resolution of GSI B-56, Diesel Reliability will be accomplished by issuing Regulatory Guide 1.9, Rev. 3, Selection, Design, Qualification, Testing, and Reliability of Diesel Generator Units Used as Onsite Electric Power Systems at Nuclear Plants. This revision will integrate into a single regulatory guide pertinent guidance previously addressed in R.G. 1.9, Rev. 2, R.G. 1.108, and Generic Letter 84-15. R.G. 1.9 has been expanded to define the principal elements of an EDG reliability program for monitoring and maintaining EDG reliability levels selected for SBO. In addition, alert levels and corrective actions have been defined to detect a deteriorating situation for all EDGs assigned to a particular nuclear unit, as well as an individual problem EDG

Reliable design of electronic equipment an engineering guide

CERN Document Server

Natarajan, Dhanasekharan

2014-01-01

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

Reliability and validity of DS-ADHD: A decision support system on attention deficit hyperactivity disorders.

Science.gov (United States)

Chu, Kuo-Chung; Huang, Yu-Shu; Tseng, Chien-Fu; Huang, Hsin-Jou; Wang, Chih-Huan; Tai, Hsin-Yi

2017-03-01

The purpose of this study is to examine the reliability of the clinical use of the self-built decision support system, diagnosis-supported attention deficit hyperactivity disorder (DS-ADHD), in an effort to develop the DS-ADHD system, by probing into the development of indicating patterns of past screening support systems for ADHD. The study collected data based on 107 subjects, who were divided into two groups, non-ADHD and ADHD, based on the doctor's determination, using the DSM-IV diagnostic standards. The two groups then underwent Test of Variables of Attention (TOVA) and DS-ADHD testing. The survey and testing results underwent one-way ANOVA and split-half method statistical analysis, in order to further understand whether there were any differences between the DS-ADHD and the identification tools used in today's clinical trials. The results of the study are as follows: 1) The ROC area between the TOVA and the clinical identification rate is 0.787 (95% confidence interval: 0.701-0.872); 2) The ROC area between the DS-ADHD and the clinical identification rate is 0.867 (95% confidence interval: 0.801-0.933). The study results show that DS-ADHD has the characteristics of screening for ADHD, based on its reliability and validity. It does not display any statistical differences when compared with TOVA systems that are currently on the market. However, the system is more effective and the accuracy rate is better than TOVA. It is a good tool to screen ADHD not only in Chinese children, but also in western country. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

The human factor in operation and maintenance of complex high-reliability systems

International Nuclear Information System (INIS)

Ryan, T.G.

1989-01-01

Human factors issues in probabilistic risk assessment (PRAs) of complex high-reliability systems are addressed. These PRAs influence system operation and technical support programs such as maintainability, test, and surveillance. Using the U.S. commercial nuclear power industry as the setting, the paper addresses the manner in which PRAs currently treat human performance, the state of quantification methods and source data for analyzing human performance, and the role of human factors specialist in the analysis. The paper concludes with a presentation of TALENT, an emerging concept for fully integrating broad-based human factors expertise into the PRA process, is presented. 47 refs

Emergency diesel generator reliability program

International Nuclear Information System (INIS)

Serkiz, A.W.

1989-01-01

The need for an emergency diesel generator (EDG) reliability program has been established by 10 CFR Part 50, Section 50.63, Loss of All Alternating Current Power, which requires that utilities assess their station blackout duration and recovery capability. EDGs are the principal emergency ac power sources for coping with a station blackout. Regulatory Guide 1.155, Station Blackout, identifies a need for (1) an EDG reliability equal to or greater than 0.95, and (2) an EDG reliability program to monitor and maintain the required levels. The resolution of Generic Safety Issue (GSI) B-56 embodies the identification of a suitable EDG reliability program structure, revision of pertinent regulatory guides and Tech Specs, and development of an Inspection Module. Resolution of B-56 is coupled to the resolution of Unresolved Safety Issue (USI) A-44, Station Blackout, which resulted in the station blackout rule, 10 CFR 50.63 and Regulatory Guide 1.155, Station Blackout. This paper discusses the principal elements of an EDG reliability program developed for resolving GSI B-56 and related matters

Reliability of nuclear power plants and equipment

International Nuclear Information System (INIS)

1985-01-01

The standard sets the general principles, a list of reliability indexes and demands on their selection. Reliability indexes of nuclear power plants include the simple indexes of fail-safe operation, life and maintainability, and of storage capability. All terms and notions are explained and methods of evaluating the indexes briefly listed - statistical, and calculation experimental. The dates when the standard comes in force in the individual CMEA countries are given. (M.D.)

Suncor maintenance and reliability

Energy Technology Data Exchange (ETDEWEB)

Little, S. [Suncor Energy, Calgary, AB (Canada)

2006-07-01

Fleet maintenance and reliability at Suncor Energy was discussed in this presentation, with reference to Suncor Energy's primary and support equipment fleets. This paper also discussed Suncor Energy's maintenance and reliability standard involving people, processes and technology. An organizational maturity chart that graphed organizational learning against organizational performance was illustrated. The presentation also reviewed the maintenance and reliability framework; maintenance reliability model; the process overview of the maintenance and reliability standard; a process flow chart of maintenance strategies and programs; and an asset reliability improvement process flow chart. An example of an improvement initiative was included, with reference to a shovel reliability review; a dipper trip reliability investigation; bucket related failures by type and frequency; root cause analysis of the reliability process; and additional actions taken. Last, the presentation provided a graph of the results of the improvement initiative and presented the key lessons learned. tabs., figs.

Evaluating the Inter-Respondent (Consumer vs. Staff) Reliability and Construct Validity (SIS vs. Vineland) of the Supports Intensity Scale on a Dutch Sample

Science.gov (United States)

Claes, C.; Van Hove, G.; van Loon, J.; Vandevelde, S.; Schalock, R. L.

2009-01-01

Background: Despite various reliability studies on the Supports Intensity Scale (SIS), to date there has not been an evaluation of the reliability of client vs. staff judgments. Such determination is important, given the increasing consumer-driven approach to services. Additionally, there has not been an evaluation of the instrument's construct…

Validity and reliability of questionnaires measuring physical activity self-efficacy, enjoyment, social support among Hong Kong Chinese children

Science.gov (United States)

Physical activity (PA) correlates have not been extensively studied in Hong Kong children. The aim of this study is to assess the validity and reliability of translated scales to measure PA related self-efficacy, enjoyment and social support in Hong Kong Chinese children. Sample 1 (n=273, aged 8–12 ...

Neurophysiology underlying influence of stimulus reliability on audiovisual integration.

Science.gov (United States)

Shatzer, Hannah; Shen, Stanley; Kerlin, Jess R; Pitt, Mark A; Shahin, Antoine J

2018-01-24

We tested the predictions of the dynamic reweighting model (DRM) of audiovisual (AV) speech integration, which posits that spectrotemporally reliable (informative) AV speech stimuli induce a reweighting of processing from low-level to high-level auditory networks. This reweighting decreases sensitivity to acoustic onsets and in turn increases tolerance to AV onset asynchronies (AVOA). EEG was recorded while subjects watched videos of a speaker uttering trisyllabic nonwords that varied in spectrotemporal reliability and asynchrony of the visual and auditory inputs. Subjects judged the stimuli as in-sync or out-of-sync. Results showed that subjects exhibited greater AVOA tolerance for non-blurred than blurred visual speech and for less than more degraded acoustic speech. Increased AVOA tolerance was reflected in reduced amplitude of the P1-P2 auditory evoked potentials, a neurophysiological indication of reduced sensitivity to acoustic onsets and successful AV integration. There was also sustained visual alpha band (8-14 Hz) suppression (desynchronization) following acoustic speech onsets for non-blurred vs. blurred visual speech, consistent with continuous engagement of the visual system as the speech unfolds. The current findings suggest that increased spectrotemporal reliability of acoustic and visual speech promotes robust AV integration, partly by suppressing sensitivity to acoustic onsets, in support of the DRM's reweighting mechanism. Increased visual signal reliability also sustains the engagement of the visual system with the auditory system to maintain alignment of information across modalities. © 2018 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

High-Reliability Health Care: Getting There from Here

Science.gov (United States)

Chassin, Mark R; Loeb, Jerod M

2013-01-01

Context Despite serious and widespread efforts to improve the quality of health care, many patients still suffer preventable harm every day. Hospitals find improvement difficult to sustain, and they suffer “project fatigue” because so many problems need attention. No hospitals or health systems have achieved consistent excellence throughout their institutions. High-reliability science is the study of organizations in industries like commercial aviation and nuclear power that operate under hazardous conditions while maintaining safety levels that are far better than those of health care. Adapting and applying the lessons of this science to health care offer the promise of enabling hospitals to reach levels of quality and safety that are comparable to those of the best high-reliability organizations. Methods We combined the Joint Commission's knowledge of health care organizations with knowledge from the published literature and from experts in high-reliability industries and leading safety scholars outside health care. We developed a conceptual and practical framework for assessing hospitals’ readiness for and progress toward high reliability. By iterative testing with hospital leaders, we refined the framework and, for each of its fourteen components, defined stages of maturity through which we believe hospitals must pass to reach high reliability. Findings We discovered that the ways that high-reliability organizations generate and maintain high levels of safety cannot be directly applied to today's hospitals. We defined a series of incremental changes that hospitals should undertake to progress toward high reliability. These changes involve the leadership's commitment to achieving zero patient harm, a fully functional culture of safety throughout the organization, and the widespread deployment of highly effective process improvement tools. Conclusions Hospitals can make substantial progress toward high reliability by undertaking several specific

[The analytical reliability of clinical laboratory information and role of the standards in its support].

Science.gov (United States)

Men'shikov, V V

2012-12-01

The article deals with the factors impacting the reliability of clinical laboratory information. The differences of qualities of laboratory analysis tools produced by various manufacturers are discussed. These characteristics are the causes of discrepancy of the results of laboratory analyses of the same analite. The role of the reference system in supporting the comparability of laboratory analysis results is demonstrated. The project of national standard is presented to regulate the requirements to standards and calibrators for analysis of qualitative and non-metrical characteristics of components of biomaterials.

Formulação estratégica da manutenção industrial com base na confiabilidade dos equipamentos Strategic formulation of industrial maintenance supported by equipment's reliability

Directory of Open Access Journals (Sweden)

Miguel Afonso Sellitto

2005-04-01

Full Text Available Este trabalho relata o uso da confiabilidade e da manutenibilidade na formulação de estratégias de manutenção industrial. O método utilizado foi o estudo de dois casos. Inicia-se revisando conceitos ligados a variáveis e processos aleatórios como base para definir conceitos e características de estudos de confiabilidade e de modelagem aplicados na gestão da manutenção industrial. A seguir se descrevem os casos estudados, em que se aplicam técnicas de modelagem de tempos até a falha e até o reparo no estabelecimento de estratégias de manutenção em fábricas do setor metal-mecânico. Com base nos resultados, discute-se o caso, estabelecendo condições para o uso da confiabilidade na formulação estratégica da manutenção, principalmente quanto ao sistema de informações necessárias.This paper reports the use of reliability and maintainability assessments in the strategic formulation of industrial maintenance. The method was a double case study. The paper begins by a theoretical review of related concepts of stochastic variables and processes as a basis to address concepts and features from reliability studies and modeling, suited to use in managing the industrial maintenance. One then describes the two studied cases, in which the reliability techniques were applied, in modeling the times to failure and times to the repair for the sake of settling the strategic formulation of industrial maintenance in metal-mechanic plants. Supported by results, this paper discusses the cases, arising requirements to the use of the reliability, mainly related to the information system.

Incremental support vector machines for fast reliable image recognition

International Nuclear Information System (INIS)

Makili, L.; Vega, J.; Dormido-Canto, S.

2013-01-01

Highlights: ► A conformal predictor using SVM as the underlying algorithm was implemented. ► It was applied to image recognition in the TJ–II's Thomson Scattering Diagnostic. ► To improve time efficiency an approach to incremental SVM training has been used. ► Accuracy is similar to the one reached when standard SVM is used. ► Computational time saving is significant for large training sets. -- Abstract: This paper addresses the reliable classification of images in a 5-class problem. To this end, an automatic recognition system, based on conformal predictors and using Support Vector Machines (SVM) as the underlying algorithm has been developed and applied to the recognition of images in the Thomson Scattering Diagnostic of the TJ–II fusion device. Using such conformal predictor based classifier is a computationally intensive task since it implies to train several SVM models to classify a single example and to perform this training from scratch takes a significant amount of time. In order to improve the classification time efficiency, an approach to the incremental training of SVM has been used as the underlying algorithm. Experimental results show that the overall performance of the new classifier is high, comparable to the one corresponding to the use of standard SVM as the underlying algorithm and there is a significant improvement in time efficiency

Incremental support vector machines for fast reliable image recognition

Energy Technology Data Exchange (ETDEWEB)

Makili, L., E-mail: makili_le@yahoo.com [Instituto Superior Politécnico da Universidade Katyavala Bwila, Benguela (Angola); Vega, J. [Asociación EURATOM/CIEMAT para Fusión, Madrid (Spain); Dormido-Canto, S. [Dpto. Informática y Automática – UNED, Madrid (Spain)

2013-10-15

Highlights: ► A conformal predictor using SVM as the underlying algorithm was implemented. ► It was applied to image recognition in the TJ–II's Thomson Scattering Diagnostic. ► To improve time efficiency an approach to incremental SVM training has been used. ► Accuracy is similar to the one reached when standard SVM is used. ► Computational time saving is significant for large training sets. -- Abstract: This paper addresses the reliable classification of images in a 5-class problem. To this end, an automatic recognition system, based on conformal predictors and using Support Vector Machines (SVM) as the underlying algorithm has been developed and applied to the recognition of images in the Thomson Scattering Diagnostic of the TJ–II fusion device. Using such conformal predictor based classifier is a computationally intensive task since it implies to train several SVM models to classify a single example and to perform this training from scratch takes a significant amount of time. In order to improve the classification time efficiency, an approach to the incremental training of SVM has been used as the underlying algorithm. Experimental results show that the overall performance of the new classifier is high, comparable to the one corresponding to the use of standard SVM as the underlying algorithm and there is a significant improvement in time efficiency.

Tooth loss in well-maintained patients with chronic periodontitis during long-term supportive therapy in Brazil.

Science.gov (United States)

Chambrone, Luiz A; Chambrone, Leandro

2006-10-01

The objective of this retrospective study was to assess the reasons for tooth loss in a sample of patients who underwent periodontal therapy and supportive periodontal therapy (SPT) in a Brazilian private periodontal practice. A sample of 120 subjects who had been treated and maintained for 10 years or longer was selected from patients attending a periodontal practice. All patients followed a similar treatment: basic procedures, re-evaluation and periodontal surgery where indicated. Reasons for tooth loss were categorized as periodontal, caries, endodontal, root fractures and extraction of retained or partially erupted third molars. Of the 2927 teeth present at the completion of active periodontal treatment, 53 (1.8%) were lost due to periodontal disease, 16 (0.5%) for root fracture, six (0.2%) to caries, five (0.2%) for endodontic reasons and 31 (1.0%) were lost to extraction of retained or partially erupted third molars. Logistic regression analysis was performed to investigate the association between five independent variables with tooth loss due to periodontitis. Only age (> 60 years) and smoking were statistically significant (p < 0.05). The findings of this survey were consistent with previous studies. Older subjects and smokers were more susceptible to periodontal tooth loss. In addition, patients with generalized chronic periodontitis were treated and maintained for long-term periods with low rates of tooth loss.

Telecommunications system reliability engineering theory and practice

CERN Document Server

Ayers, Mark L

2012-01-01

"Increasing system complexity require new, more sophisticated tools for system modeling and metric calculation. Bringing the field up to date, this book provides telecommunications engineers with practical tools for analyzing, calculating, and reporting availability, reliability, and maintainability metrics. It gives the background in system reliability theory and covers in-depth applications in fiber optic networks, microwave networks, satellite networks, power systems, and facilities management. Computer programming tools for simulating the approaches presented, using the Matlab software suite, are also provided"

78 FR 63036 - Transmission Planning Reliability Standards

Science.gov (United States)

2013-10-23

... Reliability Standards for the Bulk Power System, 130 FERC ] 61,200 (2010). \\8\\ Mandatory Reliability Standards... electric system operations across normal and contingency conditions. We also find that Reliability Standard... Reliability Standards for the Bulk Power System, 131 FERC ] 61,231 at P 21. Comments 24. NERC supports the...

Development of KSC program for investigating and generating field failure rates. Volume 2: Recommended format for reliability handbook for ground support equipment

Science.gov (United States)

Bloomquist, C. E.; Kallmeyer, R. H.

1972-01-01

Field failure rates and confidence factors are presented for 88 identifiable components of the ground support equipment at the John F. Kennedy Space Center. For most of these, supplementary information regarding failure mode and cause is tabulated. Complete reliability assessments are included for three systems, eight subsystems, and nine generic piece-part classifications. Procedures for updating or augmenting the reliability results presented in this handbook are also included.

Study of structural reliability of existing concrete structures

Science.gov (United States)

Druķis, P.; Gaile, L.; Valtere, K.; Pakrastiņš, L.; Goremikins, V.

2017-10-01

Structural reliability of buildings has become an important issue after the collapse of a shopping center in Riga 21.11.2013, caused the death of 54 people. The reliability of a building is the practice of designing, constructing, operating, maintaining and removing buildings in ways that ensure maintained health, ward suffered injuries or death due to use of the building. Evaluation and improvement of existing buildings is becoming more and more important. For a large part of existing buildings, the design life has been reached or will be reached in the near future. The structures of these buildings need to be reassessed in order to find out whether the safety requirements are met. The safety requirements provided by the Eurocodes are a starting point for the assessment of safety. However, it would be uneconomical to require all existing buildings and structures to comply fully with these new codes and corresponding safety levels, therefore the assessment of existing buildings differs with each design situation. This case study describes the simple and practical procedure of determination of minimal reliability index β of existing concrete structures designed by different codes than Eurocodes and allows to reassess the actual reliability level of different structural elements of existing buildings under design load.

Root cause analysis in support of reliability enhancement of engineering components

International Nuclear Information System (INIS)

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

2014-01-01

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

Challenges of designing fusion reactors for remote maintainability

International Nuclear Information System (INIS)

Masson, L.S.

1981-01-01

One of the major problems faced by the fusion community is the development of the high level of reliability required to assure that fusion will be a viable commercial power source. Much of the responsibility for solving this problem falls directly on the designer in developing concepts that have a high level of maintainability for the next generation engineering oriented reactors; and long range, in developing full maintainability for the more complicated commercial concepts with their required high level of on-line time. The near-term challenge will include development of unique design concepts to perform inspection, maintenance, replacement, and testing under the stringent conditions imposed by the next generation engineering oriented machines. The long range challenge will focus on basic design concepts that will enable the full maintainability required by commercial fusion. In addition to the purely technical challenges, the fusion community is also faced with the problem of developing programmatic means to assure that reactor maintenance issues are given proper and timely emphasis as the nuclear phase of fusion is approached

Development and psychometric testing of the Supportive Supervisory Scale.

Science.gov (United States)

McGilton, Katherine S

2010-06-01

To describe the development and psychometric testing of the Supportive Supervisory Scale (SSS). The development of the items of the scale was based on Winnicott's relationship theory and on focus groups with 26 healthcare aides (HCAs) and 30 supervisors from six long-term care (LTC) facilities in Ontario, Canada. Content validity of the 15-item instrument was established by a panel of experts. Based on a secondary analysis of data collected from 222 HCAs in 10 LTC facilities in Ontario, Canada, the SSS was subjected to principal components analysis with oblique rotation. A two-factor solution was accepted, which is consistent with the theoretical conceptualization of the instrument. Factor I was labeled Respects Uniqueness and Factor II was labeled Being Reliable. Internal consistency of Factor I was .95, and that of Factor II was .91. Discriminant validity was also established. The focus groups revealed that "being available to staff" while "recognizing the HCA as an individual, and taking a moment to get to know them" was essential to feeling supported by their supervisor. The SSS is a reliable and valid measure of supervisory support of supervisors working in LTC facilities. At the core of supportive supervision is the supervisor's ability to develop and maintain positive relationships with each HCA. It is through respecting the uniqueness of each HCA and being reliable that supervisor-HCA relationships can flourish. Supportive leadership in LTC settings is a major contributor to HCAs' job satisfaction and retention and to quality of patient care. Therefore, a tool developed and tested to measure supervisors' supportive capacities in LTC is primal to evaluate the effectiveness of supervisors in these environments.

On the NPP structural reliability

International Nuclear Information System (INIS)

Klemin, A.I.; Polyakov, E.F.

1980-01-01

Reviewed are the main statements peculiarities and possibilities of the first branch guiding technical material (GTM) ''The methods of calculation of structural reliability of NPP and its systems at the stage of projecting''. It is stated, that in GTM presented are recomendations on the calculation of reliability of such specific systems, as the system of the reactor control and protection the system of measuring instruments and automatics and safe systems. GTM are based on analytical methods of modern theory of realibility with the Use of metodology of minimal cross sections of complex systems. It is stressed, that the calculations on the proposed methods permit to calculate a wide complex of reliability parameters, reflecting separately or together prorerties of NPP dependability and maintainability. For NPP, operating by a variable schedule of leading, aditionally considered are parameters, characterizing reliability with account of the proposed regime of power change, i.e. taking into account failures, caused by decrease of the obtained power lower, than the reguired or increase of the required power higher, than the obtained

Exploration of reliability databases and comparison of former IFMIF's results

International Nuclear Information System (INIS)

Tapia, Carlos; Dies, Javier; Abal, Javier; Ibarra, Angel; Arroyo, Jose M.

2011-01-01

There is an uncertainty issue about the applicability of industrial databases to new designs, such as the International Fusion Materials Irradiation Facility (IFMIF), as they usually contain elements for which no historical statistics exist. The exploration of common components reliability data in Accelerator Driven Systems (ADS) and Liquid Metal Technologies (LMT) frameworks is the milestone to analyze the data used in IFMIF reliability's reports and for future studies. The comparison between the reliability accelerator results given in the former IFMIF's reports and the databases explored has been made by means of a new accelerator Reliability, Availability, Maintainability (RAM) analysis. The reliability database used in this analysis is traceable.

[Maintaining patients' autonomy at home].

Science.gov (United States)

Niang, Bénédicte; Coudre, Jean Pierre

2015-01-01

To maintain the flow of hospital discharges, the patient's return home with support from a home nursing service is important. If any difficulties are identified, there are various programmes or good practices which can be put into place. The future law on adapting society to ageing also comprises a scheme combining home assistance and nursing care.

Building and integrating reliability models in a Reliability-Centered-Maintenance approach

International Nuclear Information System (INIS)

Verite, B.; Villain, B.; Venturini, V.; Hugonnard, S.; Bryla, P.

1998-03-01

Electricite de France (EDF) has recently developed its OMF-Structures method, designed to optimize preventive maintenance of passive structures such as pipes and support, based on risk. In particular, reliability performances of components need to be determined; it is a two-step process, consisting of a qualitative sort followed by a quantitative evaluation, involving two types of models. Initially, degradation models are widely used to exclude some components from the field of preventive maintenance. The reliability of the remaining components is then evaluated by means of quantitative reliability models. The results are then included in a risk indicator that is used to directly optimize preventive maintenance tasks. (author)

High-reliability health care: getting there from here.

Science.gov (United States)

Chassin, Mark R; Loeb, Jerod M

2013-09-01

Despite serious and widespread efforts to improve the quality of health care, many patients still suffer preventable harm every day. Hospitals find improvement difficult to sustain, and they suffer "project fatigue" because so many problems need attention. No hospitals or health systems have achieved consistent excellence throughout their institutions. High-reliability science is the study of organizations in industries like commercial aviation and nuclear power that operate under hazardous conditions while maintaining safety levels that are far better than those of health care. Adapting and applying the lessons of this science to health care offer the promise of enabling hospitals to reach levels of quality and safety that are comparable to those of the best high-reliability organizations. We combined the Joint Commission's knowledge of health care organizations with knowledge from the published literature and from experts in high-reliability industries and leading safety scholars outside health care. We developed a conceptual and practical framework for assessing hospitals' readiness for and progress toward high reliability. By iterative testing with hospital leaders, we refined the framework and, for each of its fourteen components, defined stages of maturity through which we believe hospitals must pass to reach high reliability. We discovered that the ways that high-reliability organizations generate and maintain high levels of safety cannot be directly applied to today's hospitals. We defined a series of incremental changes that hospitals should undertake to progress toward high reliability. These changes involve the leadership's commitment to achieving zero patient harm, a fully functional culture of safety throughout the organization, and the widespread deployment of highly effective process improvement tools. Hospitals can make substantial progress toward high reliability by undertaking several specific organizational change initiatives. Further research

The US Support Program to IAEA Safeguards Priority of Containment and Surveillance

Energy Technology Data Exchange (ETDEWEB)

Diaz,R.A.

2008-06-13

The United States Support Program (USSP) priority for containment and surveillance (US) focuses on maintaining or improving the reliability and cost-effectiveness of C/S systems for IAEA safeguards, expanding the number of systems that are unattended and remotely monitored, and developing verification methods that help streamline the on-site inspection process. Existing IAEA C/S systems have evolved to become complex, integrated systems, which may include active seals, nondestructive assay (NDA) instruments, video cameras, and other sensors. These systems operate autonomously. They send analytical data to IAEA headquarters where it can be reviewed. These systems present challenges to the goals of improved system performance, standardization, reliability, maintainability, documentation, and cost effectiveness. One critical lesson from past experiences is the need for cooperation and common objectives among the IAEA, the developer, and the facility operator, to create a successful, cost effective system. Recent USSP C/S activities include Rokkasho Reprocessing Plant safeguard systems, production of a new shift register, numerous vulnerability assessments of C/S systems, a conduit monitoring system which identifies tampering of IAEA conduit deployed in the field, fiber optic seal upgrades, unattended monitoring system software upgrades, next generation surveillance system which will upgrade existing camera systems, and support of the IAEA's development of the universal nondestructive assay data acquisition platform.

A novel ontology approach to support design for reliability considering environmental effects.

Science.gov (United States)

Sun, Bo; Li, Yu; Ye, Tianyuan; Ren, Yi

2015-01-01

Environmental effects are not considered sufficiently in product design. Reliability problems caused by environmental effects are very prominent. This paper proposes a method to apply ontology approach in product design. During product reliability design and analysis, environmental effects knowledge reusing is achieved. First, the relationship of environmental effects and product reliability is analyzed. Then environmental effects ontology to describe environmental effects domain knowledge is designed. Related concepts of environmental effects are formally defined by using the ontology approach. This model can be applied to arrange environmental effects knowledge in different environments. Finally, rubber seals used in the subhumid acid rain environment are taken as an example to illustrate ontological model application on reliability design and analysis.

Evaluation of mobile ad hoc network reliability using propagation-based link reliability model

International Nuclear Information System (INIS)

Padmavathy, N.; Chaturvedi, Sanjay K.

2013-01-01

A wireless mobile ad hoc network (MANET) is a collection of solely independent nodes (that can move randomly around the area of deployment) making the topology highly dynamic; nodes communicate with each other by forming a single hop/multi-hop network and maintain connectivity in decentralized manner. MANET is modelled using geometric random graphs rather than random graphs because the link existence in MANET is a function of the geometric distance between the nodes and the transmission range of the nodes. Among many factors that contribute to the MANET reliability, the reliability of these networks also depends on the robustness of the link between the mobile nodes of the network. Recently, the reliability of such networks has been evaluated for imperfect nodes (transceivers) with binary model of communication links based on the transmission range of the mobile nodes and the distance between them. However, in reality, the probability of successful communication decreases as the signal strength deteriorates due to noise, fading or interference effects even up to the nodes' transmission range. Hence, in this paper, using a propagation-based link reliability model rather than a binary-model with nodes following a known failure distribution to evaluate the network reliability (2TR m , ATR m and AoTR m ) of MANET through Monte Carlo Simulation is proposed. The method is illustrated with an application and some imperative results are also presented

A reliability program approach to operational safety

International Nuclear Information System (INIS)

Mueller, C.J.; Bezella, W.A.

1985-01-01

A Reliability Program (RP) model based on proven reliability techniques is being formulated for potential application in the nuclear power industry. Methods employed under NASA and military direction, commercial airline and related FAA programs were surveyed and a review of current nuclear risk-dominant issues conducted. The need for a reliability approach to address dependent system failures, operating and emergency procedures and human performance, and develop a plant-specific performance data base for safety decision making is demonstrated. Current research has concentrated on developing a Reliability Program approach for the operating phase of a nuclear plant's lifecycle. The approach incorporates performance monitoring and evaluation activities with dedicated tasks that integrate these activities with operation, surveillance, and maintenance of the plant. The detection, root-cause evaluation and before-the-fact correction of incipient or actual systems failures as a mechanism for maintaining plant safety is a major objective of the Reliability Program. (orig./HP)

Maintaining patients' dignity during clinical care: a qualitative interview study.

Science.gov (United States)

Lin, Yea-Pyng; Tsai, Yun-Fang

2011-02-01

This article is a report of a study undertaken to understand how nurses maintain patients' dignity in clinical practice. Dignity is a core concept in nursing care and maintaining patients' dignity is critical to their recovery. In Western countries, measures to maintain dignity in patients' care include maintaining privacy of the body, providing spatial privacy, giving sufficient time, treating patients as a whole person and allowing patients to have autonomy. However, this is an under-studied topic in Asian countries. For this qualitative descriptive study, data were collected in Taiwan in 2009 using in-depth interviews with a purposive sample of 30 nurses from a teaching hospital in eastern Taiwan. The audiotaped interviews were transcribed verbatim and analysed using content analysis. Nurses' measures to maintain dignity in patient care were captured in five themes: respect, protecting privacy, emotional support, treating all patients alike and maintaining body image. Participants did not mention beneficence, a crucial element achieved through the professional care of nurses that can enhance the recovery of patients. In-service education to help nurses enhance dignity in patient care should emphasize emotional support, maintaining body image and treating all patients alike. Our model for maintaining dignity in patient care could be used to develop a clinical care protocol for nurses to use in clinical practice. © 2010 Blackwell Publishing Ltd.

A reliability-based preventive maintenance methodology for the projection spot welding machine

Directory of Open Access Journals (Sweden)

Fayzimatov Ulugbek

2018-06-01

Full Text Available An effective operations of a projection spot welding (PSW machine is closely related to the effec-tiveness of the maintenance. Timely maintenance can prevent failures and improve reliability and maintainability of the machine. Therefore, establishing the maintenance frequency for the welding machine is one of the most important tasks for plant engineers. In this regard, reliability analysis of the welding machine can be used to establish preventive maintenance intervals (PMI and to identify the critical parts of the system. In this reliability and maintainability study, analysis of the PSW machine was carried out. The failure and repair data for analysis were obtained from automobile manufacturing company located in Uzbekistan. The machine was divided into three main sub-systems: electrical, pneumatic and hydraulic. Different distributions functions for all sub-systems was tested and their parameters tabulated. Based on estimated parameters of the analyzed distribu-tions, PMI for the PSW machines sub-systems at different reliability levels was calculated. Finally, preventive measures for enhancing the reliability of the PSW machine sub-systems are suggested.

Assessing the potential for using wetlands as intermediary storages to conjunctively maintain ecological values and support agricultural demands.

Science.gov (United States)

Ning, Nathan S P; Watkins, Susanne C; Gawne, Ben; Nielsen, Daryl L

2012-09-30

Water sharing to meet both agricultural and environmental demands is a critical issue affecting the health of many floodplain river systems around the world. This study explored the potential for using wetlands as temporary off-river storages to conjunctively maintain ecological values and support agricultural demands by assessing the effects of artificial drawdown on wetland aquatic plant communities. An initial experiment was undertaken in outdoor mesocosms in which four different treatments were compared over a 131 day duration: (1) natural drawdown where the water was left to drawdown naturally via evaporation; (2) partial drawdown where approximately half of the volume of water was pumped out after 42 days; (3) stepped drawdown where approximately half of the volume of water pumped out after 42 days, and then the remaining volume of water was pumped out after 117 days; and (4) total drawdown where all of the of water was pumped out after 117 days. A complementary field study was subsequently undertaken where two wetlands were left to drawdown naturally and two were partially drawn down artificially (i.e. had approximately half of their volume removed by pumping). Results from both of these studies indicated that neither aquatic plant abundance nor taxon richness were adversely affected by partial drawdown. Rather, both studies showed that aquatic plant communities subjected to a partial drawdown treatment became more species rich and diverse than communities subjected to a natural drawdown treatment. This suggests that it may be possible to use wetlands as intermediary storages for the dual purposes of maintaining ecological values and supporting agricultural demands. Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.

A multi-state reliability evaluation model for P2P networks

International Nuclear Information System (INIS)

Fan Hehong; Sun Xiaohan

2010-01-01

The appearance of new service types and the convergence tendency of the communication networks have endowed the networks more and more P2P (peer to peer) properties. These networks can be more robust and tolerant for a series of non-perfect operational states due to the non-deterministic server-client distributions. Thus a reliability model taking into account of the multi-state and non-deterministic server-client distribution properties is needed for appropriate evaluation of the networks. In this paper, two new performance measures are defined to quantify the overall and local states of the networks. A new time-evolving state-transition Monte Carlo (TEST-MC) simulation model is presented for the reliability analysis of P2P networks in multiple states. The results show that the model is not only valid for estimating the traditional binary-state network reliability parameters, but also adequate for acquiring the parameters in a series of non-perfect operational states, with good efficiencies, especially for highly reliable networks. Furthermore, the model is versatile for the reliability and maintainability analyses in that both the links and the nodes can be failure-prone with arbitrary life distributions, and various maintainability schemes can be applied.

Guide to Operating and Maintaining EnergySmart Schools

Energy Technology Data Exchange (ETDEWEB)

None

2010-01-01

Through a commitment to high performance, school districts are discovering that smart energy choices can create lasting benefits for students, communities, and the environment. For example, an energy efficient school district with 4,000 students can save as much as $160,000 a year in energy costs. Over 10 years, those savings can reach $1.6 million, translating into the ability to hire more teachers, purchase more textbooks and computers, or invest in additional high performance facilities. Beyond these bottomline benefits, schools can better foster student health, decrease absenteeism, and serve as centers of community life. The U.S. Department of Energy's EnergySmart Schools Program promotes a 30 percent improvement in existing school energy use. It also encourages the building of new schools that exceed code (ASHRAE 90.11999) by 50 percent or more. The program provides resources like this Guide to Operating and Maintaining EnergySmart Schools to assist school decisionmakers in planning, financing, operating, and maintaining energy efficient, high performance schools. It also offers education and training for building industry professionals. Operations and maintenance refer to all scheduled and unscheduled actions for preventing equipment failure or decline with the goal of increasing efficiency, reliability, and safety. A preventative maintenance program is the organized and planned performance of maintenance activities in order to prevent system or production problems or failures from occurring. In contrast, deferred maintenance or reactive maintenance (also called diagnostic or corrective maintenance) is conducted to address an existing problem. This guide is a primary resource for developing and implementing a districtor schoolwide operations and maintenance (O&M) program that focuses on energy efficiency. The EnergySmart Schools Solutions companion CD contains additional supporting information for design, renovation, and retrofit projects. The objective

Reliability engineering theory and practice

CERN Document Server

Birolini, Alessandro

2017-01-01

This book shows how to build in and assess reliability, availability, maintainability, and safety (RAMS) of components, equipment, and systems. It presents the state of the art of reliability (RAMS) engineering, in theory & practice, and is based on over 30 years author's experience in this field, half in industry and half as Professor of Reliability Engineering at the ETH, Zurich. The book structure allows rapid access to practical results. Methods & tools are given in a way that they can be tailored to cover different RAMS requirement levels. Thanks to Appendices A6 - A8 the book is mathematically self-contained, and can be used as a textbook or as a desktop reference with a large number of tables (60), figures (210), and examples / exercises^ 10,000 per year since 2013) were the motivation for this final edition, the 13th since 1985, including German editions. Extended and carefully reviewed to improve accuracy, it represents the continuous improvement effort to satisfy reader's needs and confidenc...

Mechanical development for reliable reactor components

International Nuclear Information System (INIS)

Ross-Ross, P.A.; Metcalfe, R.

1983-09-01

The CANDU reactor has achieved worldwide distinction because of its reliable performance. To achieve this, special attention was given to the reliability and maintainability of components in the heavy water circuits. Development programs were initiated early in the history of the CANDU reactor to improve the effectiveness of pump seals, valves, and static seals because of unacceptable performance of the commercial equipment then available. As a result, pump seals with a five year life now appear achievable, and valves and static seals are no longer a significant concern in CANDU reactors. Increasing effort is being given remotely operated tools and fabrication systems for radioactive environments

The advantages of reliability centered maintenance for standby safety systems

International Nuclear Information System (INIS)

Dam, R.F.; Ayazzudin, S.; Nickerson, J.H.; DeLong, A.I.

2002-01-01

Full text: On standby safety systems, nuclear plants have to balance the requirements of demonstrating the reliability of each system, while maintaining the system and plant availability. With the goal of demonstrating statistical reliability, these systems have extensive testing programs, which often makes the system unavailable and this can impact the plant capacity. The inputs to the process are often safety and regulatory related, resulting in programs that provide a high level of scrutiny on the systems being considered. In such cases, the value of the application of a maintenance optimization strategy, such as Reliability Centered Maintenance (RCM), is questioned. Part of the question stems from the use of the word 'Reliability' in RCM, which implies a level of redundancy when applied to a system maintenance program driven by reliability requirements. A deeper look at the RCM process, however, shows that RCM has the goal of ensuring that the system operates 'reliably' through the application of an integrated maintenance strategy. This is a subtle, but important distinction. Although the system reliability requirements are an important part of the strategy evaluation, RCM provides a broader context where testing is only one part of an overall strategy focused on ensuring that component function is maintained through a combination of monitoring technologies (including testing), predictive techniques, and intrusive maintenance strategies. Each strategy is targeted to identify known component degradation mechanisms. The conclusion is that a maintenance program driven by reliability requirements will tend to have testing defined at a frequency intended to support the needed statistics. The testing demonstrates that the desired function is available today. Maintenance driven by functional requirements and known failure causes, as developed through an RCM assessment, will have frequencies tied to industry experience with components and rely on a higher degree of

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...

Reliability data bank in electronics: ITALTEL experience over 10 years of operation

International Nuclear Information System (INIS)

Turconi, G.

1986-01-01

The purpose of this paper is to show the Italtel Reliability Data Bank experience in electronics after ten years from data bank creation. Technological evolution on systems and equipment have originated a reliability data bank evolution in order to maintain and improve its performances. This paper will describe the concepts employed to design the today data bank features enabling it to be an important Company tool for reliability activities. (orig.)

Reliability issues : a Canadian perspective

International Nuclear Information System (INIS)

Konow, H.

2004-01-01

A Canadian perspective of power reliability issues was presented. Reliability depends on adequacy of supply and a framework for standards. The challenges facing the electric power industry include new demand, plant replacement and exports. It is expected that demand will by 670 TWh by 2020, with 205 TWh coming from new plants. Canada will require an investment of $150 billion to meet this demand and the need is comparable in the United States. As trade grows, the challenge becomes a continental issue and investment in the bi-national transmission grid will be essential. The 5 point plan of the Canadian Electricity Association is to: (1) establish an investment climate to ensure future electricity supply, (2) move government and industry towards smart and effective regulation, (3) work to ensure a sustainable future for the next generation, (4) foster innovation and accelerate skills development, and (5) build on the strengths of an integrated North American system to maximize opportunity for Canadians. The CEA's 7 measures that enhance North American reliability were listed with emphasis on its support for a self-governing international organization for developing and enforcing mandatory reliability standards. CEA also supports the creation of a binational Electric Reliability Organization (ERO) to identify and solve reliability issues in the context of a bi-national grid. tabs., figs

Reliability and efficiency upgrades of power systems operation by implementing intelligent electronic devices with synchrophasor measurement technology support

OpenAIRE

Mokeev Alexey

2017-01-01

This paper reviews issues of reliability and efficiency upgrades of power systems functions by means of a widespread implementation of intelligent electronic devices (IED) in various purposes supporting synchrophasor measurement technology. Thus, such issues as IED’s operational analysis in the conditions of electromagnetic and electromechanical transient processes and synthesis of digital filters that improve static and dynamic responses of these devices play an important role in their devel...

Managing relationships between electric power industry restructuring and grid reliability

International Nuclear Information System (INIS)

Thomas, R.J.

2005-01-01

The electricity system is a critical infrastructure, and its continued and reliable functioning is essential to the nation's economy and well-being. However, the inter-dependency of electricity networks is not completely understood. The economic impact of outages was discussed in this white paper. It was suggested that moving to a restructured environment has degraded the reliability of the bulk system. New institutional arrangements and approaches to information management are needed. It was suggested that reliability practices caused the 2003 blackout, and not technical failures. Uncertainties in the restructured market were discussed, as well as incentives to maintain system adequacy. Examples of deregulation in other countries were presented. Organizational complexities were reviewed, including the Federal Energy Regulatory Commission's (FERC) requirements and the new layers of complexity that have been added to the decision-making process in the light of restructuring. Planning and connectivity issues were reviewed. The need for design standards in power grid control centres was discussed. Difficulties in collecting data from different control centres were considered. Issues concerning the lack of investment in research and development were discussed, with particular reference to the urgent need for coordinated research programs. The looming manpower crisis in the electric power industry was also discussed. Recommendations included ensuring that the transmission system can support a market structure; building a national reliability centre; solving the manpower crisis; and testing market designs before deploying them. It was concluded that good engineering design principles, including experimental economic testing, should be required of any new electricity market design before authorizing its use. 31 refs., 1 tab., 6 figs

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.

Reliability and Validity of Qualitative and Operational Research Paradigm

Directory of Open Access Journals (Sweden)

Muhammad Bashir

2008-01-01

Full Text Available Both qualitative and quantitative paradigms try to find the same result; the truth. Qualitative studies are tools used in understanding and describing the world of human experience. Since we maintain our humanity throughout the research process, it is largely impossible to escape the subjective experience, even for the most experienced of researchers. Reliability and Validity are the issue that has been described in great deal by advocates of quantitative researchers. The validity and the norms of rigor that are applied to quantitative research are not entirely applicable to qualitative research. Validity in qualitative research means the extent to which the data is plausible, credible and trustworthy; and thus can be defended when challenged. Reliability and validity remain appropriate concepts for attaining rigor in qualitative research. Qualitative researchers have to salvage responsibility for reliability and validity by implementing verification strategies integral and self-correcting during the conduct of inquiry itself. This ensures the attainment of rigor using strategies inherent within each qualitative design, and moves the responsibility for incorporating and maintaining reliability and validity from external reviewers’ judgments to the investigators themselves. There have different opinions on validity with some suggesting that the concepts of validity is incompatible with qualitative research and should be abandoned while others argue efforts should be made to ensure validity so as to lend credibility to the results. This paper is an attempt to clarify the meaning and use of reliability and validity in the qualitative research paradigm.

Configuration management issues and objectives for a real-time research flight test support facility

Science.gov (United States)

Yergensen, Stephen; Rhea, Donald C.

1988-01-01

Presented are some of the critical issues and objectives pertaining to configuration management for the NASA Western Aeronautical Test Range (WATR) of Ames Research Center. The primary mission of the WATR is to provide a capability for the conduct of aeronautical research flight test through real-time processing and display, tracking, and communications systems. In providing this capability, the WATR must maintain and enforce a configuration management plan which is independent of, but complimentary to, various research flight test project configuration management systems. A primary WATR objective is the continued development of generic research flight test project support capability, wherein the reliability of WATR support provided to all project users is a constant priority. Therefore, the processing of configuration change requests for specific research flight test project requirements must be evaluated within a perspective that maintains this primary objective.

Wind turbine reliability : a database and analysis approach.

Energy Technology Data Exchange (ETDEWEB)

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

2008-02-01

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

Reliability and efficiency upgrades of power systems operation by implementing intelligent electronic devices with synchrophasor measurement technology support

Directory of Open Access Journals (Sweden)

Mokeev Alexey

2017-01-01

Full Text Available This paper reviews issues of reliability and efficiency upgrades of power systems functions by means of a widespread implementation of intelligent electronic devices (IED in various purposes supporting synchrophasor measurement technology. Thus, such issues as IED’s operational analysis in the conditions of electromagnetic and electromechanical transient processes and synthesis of digital filters that improve static and dynamic responses of these devices play an important role in their development.

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

State Support of Domestic Production

Energy Technology Data Exchange (ETDEWEB)

Amy Wright

2007-12-30

This project was developed in response to a cooperative agreement offering by the U.S. Department of Energy (DOE) and the National Energy Technology Laboratory (NETL) under the State Support of Domestic Production DE-FC26-04NT15456. The Interstate Oil and Gas Compact Commission (IOGCC) performed efforts in support of State programs related to the security, reliability and growth if our nation's domestic production of oil and natural gas. The project objectives were to improve the States ability to monitor the security of oil and gas operations; to maximize the production of domestic oil and natural gas thereby minimizing the threat to national security posed by interruptions in energy imports; to assist States in developing and maintaining high standards of environmental protection; to assist in addressing issues that limit the capacity of the industry; to promote the deployment of the appropriate application of technology for regulatory efficiency; and to inform the public about emerging energy issues.

Need for Cost Optimization of Space Life Support Systems

Science.gov (United States)

Jones, Harry W.; Anderson, Grant

2017-01-01

As the nation plans manned missions that go far beyond Earth orbit to Mars, there is an urgent need for a robust, disciplined systems engineering methodology that can identify an optimized Environmental Control and Life Support (ECLSS) architecture for long duration deep space missions. But unlike the previously used Equivalent System Mass (ESM), the method must be inclusive of all driving parameters and emphasize the economic analysis of life support system design. The key parameter for this analysis is Life Cycle Cost (LCC). LCC takes into account the cost for development and qualification of the system, launch costs, operational costs, maintenance costs and all other relevant and associated costs. Additionally, an effective methodology must consider system technical performance, safety, reliability, maintainability, crew time, and other factors that could affect the overall merit of the life support system.

Life Support for Deep Space and Mars

Science.gov (United States)

Jones, Harry W.; Hodgson, Edward W.; Kliss, Mark H.

2014-01-01

How should life support for deep space be developed? The International Space Station (ISS) life support system is the operational result of many decades of research and development. Long duration deep space missions such as Mars have been expected to use matured and upgraded versions of ISS life support. Deep space life support must use the knowledge base incorporated in ISS but it must also meet much more difficult requirements. The primary new requirement is that life support in deep space must be considerably more reliable than on ISS or anywhere in the Earth-Moon system, where emergency resupply and a quick return are possible. Due to the great distance from Earth and the long duration of deep space missions, if life support systems fail, the traditional approaches for emergency supply of oxygen and water, emergency supply of parts, and crew return to Earth or escape to a safe haven are likely infeasible. The Orbital Replacement Unit (ORU) maintenance approach used by ISS is unsuitable for deep space with ORU's as large and complex as those originally provided in ISS designs because it minimizes opportunities for commonality of spares, requires replacement of many functional parts with each failure, and results in substantial launch mass and volume penalties. It has become impractical even for ISS after the shuttle era, resulting in the need for ad hoc repair activity at lower assembly levels with consequent crew time penalties and extended repair timelines. Less complex, more robust technical approaches may be needed to meet the difficult deep space requirements for reliability, maintainability, and reparability. Developing an entirely new life support system would neglect what has been achieved. The suggested approach is use the ISS life support technologies as a platform to build on and to continue to improve ISS subsystems while also developing new subsystems where needed to meet deep space requirements.

Safety, reliability and worker satisfaction during organizational change

NARCIS (Netherlands)

Zwetsloot, G.I.J.M.; Drupsteen, L.; Vroome, E.M.M. de

2014-01-01

The research presented in this paper was carried out in four process industry plants in the Netherlands, to identify factors that have the potential to increase safety and reliability while maintaining or improving job satisfaction. The data used were gathered as part of broader trajectories in

STARS software tool for analysis of reliability and safety

International Nuclear Information System (INIS)

Poucet, A.; Guagnini, E.

1989-01-01

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

Application of reliability methods in Ontario Hydro

International Nuclear Information System (INIS)

Jeppesen, R.; Ravishankar, T.J.

1985-01-01

Ontario Hydro have established a reliability program in support of its substantial nuclear program. Application of the reliability program to achieve both production and safety goals is described. The value of such a reliability program is evident in the record of Ontario Hydro's operating nuclear stations. The factors which have contributed to the success of the reliability program are identified as line management's commitment to reliability; selective and judicious application of reliability methods; establishing performance goals and monitoring the in-service performance; and collection, distribution, review and utilization of performance information to facilitate cost-effective achievement of goals and improvements. (orig.)

Custom high-reliability radiation-hard CMOS-LSI circuit design

International Nuclear Information System (INIS)

Barnard, W.J.

1981-01-01

Sandia has developed a custom CMOS-LSI design capability to provide high reliability radiation-hardened circuits. This capability relies on (1) proven design practices to enhance reliability, (2) use of well characterized cells and logic modules, (3) computer-aided design tools to reduce design time and errors and to standardize design definition, and (4) close working relationships with the system designer and technology fabrication personnel. Trade-offs are made during the design between circuit complexity/performance and technology/producibility for high reliability and radiation-hardened designs to result. Sandia has developed and is maintaining a radiation-hardened bulk CMOS technology fabrication line for production of prototype and small production volume parts

Integrated Logistics Support approach: concept for the new big projects: E-ELT, SKA, CTA

Science.gov (United States)

Marchiori, G.; Rampini, F.; Formentin, F.

2014-08-01

The Integrated Logistic Support is a process supporting strategies and optimizing activities for a correct project management and system engineering development. From the design & engineering of complex technical systems, to the erection on site, acceptance and after-sales service, EIE GROUP covers all aspects of the Integrated Logistics Support (ILS) process that includes: costing process centered around the life cycle cost and Level of Repair Analyses; engineering process which influences the design via means of reliability, modularization, etc.; technical publishing process based on international specifications; ordering administration process for supply support. Through the ILS, EIE GROUP plans and directs the identification and development of logistics support and system requirements for its products, with the goal of creating systems that last longer and require less support, thereby reducing costs and increasing return on investments. ILS therefore, addresses these aspects of supportability not only during acquisition, but also throughout the operational life cycle of the system. The impact of the ILS is often measured in terms of metrics such as reliability, availability, maintainability and testability (RAMT), and System Safety (RAMS). Example of the criteria and approach adopted by EIE GROUP during the design, manufacturing and test of the ALMA European Antennas and during the design phase of the E-ELT telescope and Dome are presented.

Telepsychiatry clinical decision support system used by non-psychiatrists in remote areas: Validity & reliability of diagnostic module

Science.gov (United States)

Malhotra, Savita; Chakrabarti, Subho; Shah, Ruchita; Sharma, Minali; Sharma, Kanu Priya; Malhotra, Akanksha; Upadhyaya, Suneet K.; Margoob, Mushtaq A.; Maqbool, Dar; Jassal, Gopal D.

2017-01-01

Background & objectives: A knowledge-based, logically-linked online telepsychiatric decision support system for diagnosis and treatment of mental disorders was developed and validated. We evaluated diagnostic accuracy and reliability of the application at remote sites when used by non-psychiatrists who underwent a brief training in its use through video-conferencing. Methods: The study was conducted at a nodal telepsychiatry centre, and three geographically remote peripheral centres. The diagnostic tool of application had a screening followed by detailed criteria-wise diagnostic modules for 18 psychiatric disorders. A total of 100 consecutive consenting adult outpatients attending remote telepsychiatry centres were included. To assess inter-rater reliability, patients were interviewed face to face by non-specialists at remote sites using the application (active interviewer) and simultaneously on online application via video-conferencing by a passive assessor at nodal centre. Another interviewer at the nodal centre rated the patient using Mini-International Neuropsychiatric Interview (MINI) for diagnostic validation. Results: Screening sub-module had high sensitivity (80-100%), low positive predictive values (PPV) (0.10-0.71) but high negative predictive value (NPV) (0.97-1) for most disorders. For the diagnostic sub-modules, Cohen's kappa was >0.4 for all disorders, with kappa of 0.7-1.0 for most disorders. PPV and NPV were high for most disorders. Inter-rater agreement analysis revealed kappa >0.6 for all disorders. Interpretation & conclusions: Diagnostic tool showed acceptable to good validity and reliability when used by non-specialists at remote sites. Our findings show that diagnostic tool of the telepsychiatry application has potential to empower non-psychiatrist doctors and paramedics to diagnose psychiatric disorders accurately and reliably in remote sites. PMID:29265020

Nuclear reliability assurance data source guide

International Nuclear Information System (INIS)

1976-11-01

Seven sources of reliability and maintainability data are reviewed for their potential for providing nuclear equipment data. Consideration is given to similarity to nuclear application, variety of equipment types reported, availability of data, and obsolescence of data. In addition, discussions of advantages and disadvantages of each data source are presented, and samples of either the data or the character of the data are included as appendixes

Techniques for increasing the reliability of accelerator control system electronics

International Nuclear Information System (INIS)

Utterback, J.

1993-09-01

As the physical size of modern accelerators becomes larger and larger, the number of required control system circuit boards increases, and the probability of one of those circuit boards failing while in service also increases. In order to do physics, the experimenters need the accelerator to provide beam reliably with as little down time as possible. With the advent of colliding beams physics, reliability becomes even more important due to the fact that a control system failure can cause the loss of painstakingly produced antiprotons. These facts prove the importance of keeping reliability in mind when designing and maintaining accelerator control system electronics

Evaluation of research reactor fuel reliability in support of regulatory requirements

International Nuclear Information System (INIS)

Sokolov, Eugene N.

2005-01-01

This standards, codes and practices survey is devoted to the problem of reliability of R and D especially research reactor fuel (RRF) performance-related processes. Regulatory R and D evaluations were based on one standard and just few of them provide correlation to other relative standards whereas synthetic process approach reflects actual status of particular R and D practices. Fuel performance regulatory parameters are based on quality standards. A reliability process-based method similar to PSA/FMEA is proposed to evaluate RRF performance- related parameters in terms of reactor safety. (author)

Evaluation of research reactor fuel reliability in support of regulatory requirements

Energy Technology Data Exchange (ETDEWEB)

Sokolov, Eugene N [Chalk River Laboratories, AECL, Chalk River, ON, K0J 1J0 (Canada)

2005-07-01

This standards, codes and practices survey is devoted to the problem of reliability of R and D especially research reactor fuel (RRF) performance-related processes. Regulatory R and D evaluations were based on one standard and just few of them provide correlation to other relative standards whereas synthetic process approach reflects actual status of particular R and D practices. Fuel performance regulatory parameters are based on quality standards. A reliability process-based method similar to PSA/FMEA is proposed to evaluate RRF performance- related parameters in terms of reactor safety. (author)

NASA Applications and Lessons Learned in Reliability Engineering

Science.gov (United States)

Safie, Fayssal M.; Fuller, Raymond P.

2011-01-01

Since the Shuttle Challenger accident in 1986, communities across NASA have been developing and extensively using quantitative reliability and risk assessment methods in their decision making process. This paper discusses several reliability engineering applications that NASA has used over the year to support the design, development, and operation of critical space flight hardware. Specifically, the paper discusses several reliability engineering applications used by NASA in areas such as risk management, inspection policies, components upgrades, reliability growth, integrated failure analysis, and physics based probabilistic engineering analysis. In each of these areas, the paper provides a brief discussion of a case study to demonstrate the value added and the criticality of reliability engineering in supporting NASA project and program decisions to fly safely. Examples of these case studies discussed are reliability based life limit extension of Shuttle Space Main Engine (SSME) hardware, Reliability based inspection policies for Auxiliary Power Unit (APU) turbine disc, probabilistic structural engineering analysis for reliability prediction of the SSME alternate turbo-pump development, impact of ET foam reliability on the Space Shuttle System risk, and reliability based Space Shuttle upgrade for safety. Special attention is given in this paper to the physics based probabilistic engineering analysis applications and their critical role in evaluating the reliability of NASA development hardware including their potential use in a research and technology development environment.

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)

Groningen orthopaedic social support scale: Validity and reliability

NARCIS (Netherlands)

van den Akker-Scheek, I.; Stevens, M.; Spriensma, A.; van Horn, J.R.

2004-01-01

BACKGROUND: Social support is an important factor in the rehabilitation process, as it has a positive influence on patients' health, functioning and recovery. In particular, perceived social support and instrumental support are important after total hip or knee arthroplasty. However, nursing staff

Reliability tasks from prediction to field use

International Nuclear Information System (INIS)

Guyot, Christian.

1975-01-01

This tutorial paper is part of a series intended to sensitive on reliability prolems. Reliability probabilistic concept, is an important parameter of availability. Reliability prediction is an estimation process for evaluating design progress. It is only by the application of a reliability program that reliability objectives can be attained through the different stages of work: conception, fabrication, field use. The user is mainly interested in operational reliability. Indication are given on the support and the treatment of data in the case of electronic equipment at C.E.A. Reliability engineering requires a special state of mind which must be formed and developed in a company in the same way as it may be done for example for safety [fr

Reliability: How much is it worth? Beyond its estimation or prediction, the (net) present value of reliability

International Nuclear Information System (INIS)

Saleh, J.H.; Marais, K.

2006-01-01

In this article, we link an engineering concept, reliability, to a financial and managerial concept, net present value, by exploring the impact of a system's reliability on its revenue generation capability. The framework here developed for non-repairable systems quantitatively captures the value of reliability from a financial standpoint. We show that traditional present value calculations of engineering systems do not account for system reliability, thus over-estimate a system's worth and can therefore lead to flawed investment decisions. It is therefore important to involve reliability engineers upfront before investment decisions are made in technical systems. In addition, the analyses here developed help designers identify the optimal level of reliability that maximizes a system's net present value-the financial value reliability provides to the system minus the cost to achieve this level of reliability. Although we recognize that there are numerous considerations driving the specification of an engineering system's reliability, we contend that the financial analysis of reliability here developed should be made available to decision-makers to support in part, or at least be factored into, the system reliability specification

Reliability and failure modes of implant-supported zirconium-oxide fixed dental prostheses related to veneering techniques

Science.gov (United States)

Baldassarri, Marta; Zhang, Yu; Thompson, Van P.; Rekow, Elizabeth D.; Stappert, Christian F. J.

2011-01-01

Summary Objectives To compare fatigue failure modes and reliability of hand-veneered and over-pressed implant-supported three-unit zirconium-oxide fixed-dental-prostheses(FDPs). Methods Sixty-four custom-made zirconium-oxide abutments (n=32/group) and thirty-two zirconium-oxide FDP-frameworks were CAD/CAM manufactured. Frameworks were veneered with hand-built up or over-pressed porcelain (n=16/group). Step-stress-accelerated-life-testing (SSALT) was performed in water applying a distributed contact load at the buccal cusp-pontic-area. Post failure examinations were carried out using optical (polarized-reflected-light) and scanning electron microscopy (SEM) to visualize crack propagation and failure modes. Reliability was compared using cumulative-damage step-stress analysis (Alta-7-Pro, Reliasoft). Results Crack propagation was observed in the veneering porcelain during fatigue. The majority of zirconium-oxide FDPs demonstrated porcelain chipping as the dominant failure mode. Nevertheless, fracture of the zirconium-oxide frameworks was also observed. Over-pressed FDPs failed earlier at a mean failure load of 696 ± 149 N relative to hand-veneered at 882 ± 61 N (profile I). Weibull-stress-number of cycles-unreliability-curves were generated. The reliability (2-sided at 90% confidence bounds) for a 400N load at 100K cycles indicated values of 0.84 (0.98-0.24) for the hand-veneered FDPs and 0.50 (0.82-0.09) for their over-pressed counterparts. Conclusions Both zirconium-oxide FDP systems were resistant under accelerated-life-time-testing. Over-pressed specimens were more susceptible to fatigue loading with earlier veneer chipping. PMID:21557985

Analyses of inter-rater reliability between professionals, medical students and trained school children as assessors of basic life support skills.

Science.gov (United States)

Beck, Stefanie; Ruhnke, Bjarne; Issleib, Malte; Daubmann, Anne; Harendza, Sigrid; Zöllner, Christian

2016-10-07

Training of lay-rescuers is essential to improve survival-rates after cardiac arrest. Multiple campaigns emphasise the importance of basic life support (BLS) training for school children. Trainings require a valid assessment to give feedback to school children and to compare the outcomes of different training formats. Considering these requirements, we developed an assessment of BLS skills using MiniAnne and tested the inter-rater reliability between professionals, medical students and trained school children as assessors. Fifteen professional assessors, 10 medical students and 111-trained school children (peers) assessed 1087 school children at the end of a CPR-training event using the new assessment format. Analyses of inter-rater reliability (intraclass correlation coefficient; ICC) were performed. Overall inter-rater reliability of the summative assessment was high (ICC = 0.84, 95 %-CI: 0.84 to 0.86, n = 889). The number of comparisons between peer-peer assessors (n = 303), peer-professional assessors (n = 339), and peer-student assessors (n = 191) was adequate to demonstrate high inter-rater reliability between peer- and professional-assessors (ICC: 0.76), peer- and student-assessors (ICC: 0.88) and peer- and other peer-assessors (ICC: 0.91). Systematic variation in rating of specific items was observed for three items between professional- and peer-assessors. Using this assessment and integrating peers and medical students as assessors gives the opportunity to assess hands-on skills of school children with high reliability.

Optimizing multiple reliable forward contracts for reservoir allocation using multitime scale streamflow forecasts

Science.gov (United States)

Lu, Mengqian; Lall, Upmanu; Robertson, Andrew W.; Cook, Edward

2017-03-01

Streamflow forecasts at multiple time scales provide a new opportunity for reservoir management to address competing objectives. Market instruments such as forward contracts with specified reliability are considered as a tool that may help address the perceived risk associated with the use of such forecasts in lieu of traditional operation and allocation strategies. A water allocation process that enables multiple contracts for water supply and hydropower production with different durations, while maintaining a prescribed level of flood risk reduction, is presented. The allocation process is supported by an optimization model that considers multitime scale ensemble forecasts of monthly streamflow and flood volume over the upcoming season and year, the desired reliability and pricing of proposed contracts for hydropower and water supply. It solves for the size of contracts at each reliability level that can be allocated for each future period, while meeting target end of period reservoir storage with a prescribed reliability. The contracts may be insurable, given that their reliability is verified through retrospective modeling. The process can allow reservoir operators to overcome their concerns as to the appropriate skill of probabilistic forecasts, while providing water users with short-term and long-term guarantees as to how much water or energy they may be allocated. An application of the optimization model to the Bhakra Dam, India, provides an illustration of the process. The issues of forecast skill and contract performance are examined. A field engagement of the idea is useful to develop a real-world perspective and needs a suitable institutional environment.

Structural Reliability Analysis of Wind Turbines: A Review

Directory of Open Access Journals (Sweden)

Zhiyu Jiang

2017-12-01

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

Teach, learn, and motivate: tools to reliability, availability, and maintainability

International Nuclear Information System (INIS)

Allison, D.

1986-01-01

The recent introduction of performance-based training by the Institute for Nuclear Power Operations (INPO) should not be a surprise to the nuclear industry. The recommended performance-based training method by INPO in one form or another addresses the techniques of teaching and sets the atmosphere for employee learning and motivation. The purpose of this paper is to explore the underlying concepts of why performance-based training yields such high results. The main emphasis will be on the general topics of teaching, learning, and student motivation as each applies to hands-on training. To support each of these topics, ancient philosophers' theories are presented. the intent is to show that hands-on performance-based training applies to engineers and other professional disciplines as well as technicians and operators

Integrated Logistics Support Analysis of the International Space Station Alpha: An Overview of the Maintenance Time Dependent Parameter Prediction Methods Enhancement

Science.gov (United States)

Sepehry-Fard, F.; Coulthard, Maurice H.

1995-01-01

The objective of this publication is to introduce the enhancement methods for the overall reliability and maintainability methods of assessment on the International Space Station. It is essential that the process to predict the values of the maintenance time dependent variable parameters such as mean time between failure (MTBF) over time do not in themselves generate uncontrolled deviation in the results of the ILS analysis such as life cycle costs, spares calculation, etc. Furthermore, the very acute problems of micrometeorite, Cosmic rays, flares, atomic oxygen, ionization effects, orbital plumes and all the other factors that differentiate maintainable space operations from non-maintainable space operations and/or ground operations must be accounted for. Therefore, these parameters need be subjected to a special and complex process. Since reliability and maintainability strongly depend on the operating conditions that are encountered during the entire life of the International Space Station, it is important that such conditions are accurately identified at the beginning of the logistics support requirements process. Environmental conditions which exert a strong influence on International Space Station will be discussed in this report. Concurrent (combined) space environments may be more detrimental to the reliability and maintainability of the International Space Station than the effects of a single environment. In characterizing the logistics support requirements process, the developed design/test criteria must consider both the single and/or combined environments in anticipation of providing hardware capability to withstand the hazards of the International Space Station profile. The effects of the combined environments (typical) in a matrix relationship on the International Space Station will be shown. The combinations of the environments where the total effect is more damaging than the cumulative effects of the environments acting singly, may include a

John F. Kennedy Space Center, Safety, Reliability, Maintainability and Quality Assurance, Survey and Audit Program

Science.gov (United States)

1994-01-01

This document is the product of the KSC Survey and Audit Working Group composed of civil service and contractor Safety, Reliability, and Quality Assurance (SR&QA) personnel. The program described herein provides standardized terminology, uniformity of survey and audit operations, and emphasizes process assessments rather than a program based solely on compliance. The program establishes minimum training requirements, adopts an auditor certification methodology, and includes survey and audit metrics for the audited organizations as well as the auditing organization.

Seamless service: maintaining momentum.

Science.gov (United States)

Grinstead, N; Timoney, R

1994-01-01

Describes the process used by the Mater Infirmorum Hospital in Belfast in 1992-1994 to achieve high quality care (Seamless Service), motivate staff to deliver and measure performance. Aims of the project include focusing the organization on the customer, improving teamwork and motivation at all levels. After comprehensive data collection from GPs, patients and staff management forums developed a full TQM strategy to gain support and maintain momentum including innovative staff events (every staff member was given the opportunity to attend) where multilevel, multidisciplinary workshops enabled staff to design customer care standards, develop teams and lead customer-driven change.

Sponsored Grant-maintained Schools: Extending the Franchise?

Science.gov (United States)

Walford, Geoffrey

1997-01-01

Discusses the introduction and implementation of the 1988 Education Reform Act for England and Wales. Traces the attempts of several existing private schools to become grant maintained (eligible for various forms of government support). Most private and faith-based schools have not been successful in this endeavor. Discusses the reasons for this.…

What to Do With "Moderate" Reliability and Validity Coefficients?

NARCIS (Netherlands)

Post, Marcel W

Clinimetric studies may use criteria for test-retest reliability and convergent validity such that correlation coefficients as low as .40 are supportive of reliability and validity. It can be argued that moderate (.40-.60) correlations should not be interpreted in this way and that reliability

[The external evaluation of study quality: the role in maintaining the reliability of laboratory information].

Science.gov (United States)

Men'shikov, V V

2013-08-01

The external evaluation of quality of clinical laboratory examinations was gradually introduced in USSR medical laboratories since 1970s. In Russia, in the middle of 1990 a unified all-national system of external evaluation quality was organized known as the Federal center of external evaluation of quality at the basis of laboratory of the state research center of preventive medicine. The main positions of policy in this area were neatly formulated in the guidance documents of ministry of Health. Nowadays, the center of external evaluation of quality proposes 100 and more types of control studies and permanently extends their specter starting from interests of different disciplines of clinical medicine. The consistent participation of laboratories in the cycles of external evaluation of quality intrinsically promotes improvement of indicators of properness and precision of analysis results and increases reliability of laboratory information. However, a significant percentage of laboratories does not participate at all in external evaluation of quality or takes part in control process irregularly and in limited number of tests. The managers of a number of medical organizations disregard the application of the proposed possibilities to increase reliability of laboratory information and limit financing of studies in the field of quality control. The article proposes to adopt the national standard on the basis of ISO 17043 "Evaluation of compliance. The common requirements of professional competence testing".

Assessment of Advanced Life Support competence when combining different test methods--reliability and validity

DEFF Research Database (Denmark)

Ringsted, C; Lippert, F; Hesselfeldt, R

2007-01-01

Cardiac Arrest Simulation Test (CASTest) scenarios for the assessments according to guidelines 2005. AIMS: To analyse the reliability and validity of the individual sub-tests provided by ERC and to find a combination of MCQ and CASTest that provides a reliable and valid single effect measure of ALS...... that possessed high reliability, equality of test sets, and ability to discriminate between the two groups of supposedly different ALS competence. CONCLUSIONS: ERC sub-tests of ALS competence possess sufficient reliability and validity. A combined ALS score with equal weighting of one MCQ and one CASTest can...... competence. METHODS: Two groups of participants were included in this randomised, controlled experimental study: a group of newly graduated doctors, who had not taken the ALS course (N=17) and a group of students, who had passed the ALS course 9 months before the study (N=16). Reliability in terms of inter...

Reliability and availability of high power proton accelerators

International Nuclear Information System (INIS)

Cho, Y.

1999-01-01

It has become increasingly important to address the issues of operational reliability and availability of an accelerator complex early in its design and construction phases. In this context, reliability addresses the mean time between failures and the failure rate, and availability takes into account the failure rate as well as the length of time required to repair the failure. Methods to reduce failure rates include reduction of the number of components and over-design of certain key components. Reduction of the on-line repair time can be achieved by judiciously designed hardware, quick-service spare systems and redundancy. In addition, provisions for easy inspection and maintainability are important for both reduction of the failure rate as well as reduction of the time to repair. The radiation safety exposure principle of ALARA (as low as reasonably achievable) is easier to comply with when easy inspection capability and easy maintainability are incorporated into the design. Discussions of past experience in improving accelerator availability, some recent developments, and potential R and D items are presented. (author)

Reliability study: steam generation and distribution system, Portsmouth Gaseous Diffusion Plant

International Nuclear Information System (INIS)

Baker, F.E.; Davis, E.L.; Dent, J.T.; Walters, D.E.; West, R.M.

1982-10-01

A reliability study for determining the ability of the Steam Generation and Distribution System to provide reliable and adequate service through the year 2000 has been completed. This study includes an evaluation of the X-600 Steam Plant and the steam distribution system. The Steam Generation and Distribution System is in good overall condition, but to maintain this condition, the reliability study team made twelve recommendations. Eight of the recommendations are for repair or replacement of existing equipment and have a total estimated cost of $540,000. The other four recommendations are for additional testing, new procedure implementation, or continued investigations

As reliable as the sun

Science.gov (United States)

Leijtens, J. A. P.

2017-11-01

Fortunately there is almost nothing as reliable as the sun which can consequently be utilized as a very reliable source of spacecraft power. In order to harvest this power, the solar panels have to be pointed towards the sun as accurately and reliably as possible. To this extend, sunsensors are available on almost every satellite to support vital sun-pointing capability throughout the mission, even in the deployment and save mode phases of the satellites life. Given the criticality of the application one would expect that after more than 50 years of sun sensor utilisation, such sensors would be fully matured and optimised. In actual fact though, the majority of sunsensors employed are still coarse sunsensors which have a proven extreme reliability but present major issues regarding albedo sensitivity and pointing accuracy.

Disturbance maintains alternative biome states.

Science.gov (United States)

Dantas, Vinícius de L; Hirota, Marina; Oliveira, Rafael S; Pausas, Juli G

2016-01-01

Understanding the mechanisms controlling the distribution of biomes remains a challenge. Although tropical biome distribution has traditionally been explained by climate and soil, contrasting vegetation types often occur as mosaics with sharp boundaries under very similar environmental conditions. While evidence suggests that these biomes are alternative states, empirical broad-scale support to this hypothesis is still lacking. Using community-level field data and a novel resource-niche overlap approach, we show that, for a wide range of environmental conditions, fire feedbacks maintain savannas and forests as alternative biome states in both the Neotropics and the Afrotropics. In addition, wooded grasslands and savannas occurred as alternative grassy states in the Afrotropics, depending on the relative importance of fire and herbivory feedbacks. These results are consistent with landscape scale evidence and suggest that disturbance is a general factor driving and maintaining alternative biome states and vegetation mosaics in the tropics. © 2015 John Wiley & Sons Ltd/CNRS.

A reliability analysis of the revised competitiveness index.

Science.gov (United States)

Harris, Paul B; Houston, John M

2010-06-01

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

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

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

76 FR 71011 - Reliability Technical Conference Agenda

Science.gov (United States)

2011-11-16

... process? Do you support the exemption process changes identified by the RTOs or other entities in comments... reliability plans? b. Do you support the exemption process changes identified by the RTOs or other entities in...

Factorial validity and reliability of the Malaysian simplified Chinese version of Multidimensional Scale of Perceived Social Support (MSPSS-SCV) among a group of university students.

Science.gov (United States)

Guan, Ng Chong; Seng, Loh Huai; Hway Ann, Anne Yee; Hui, Koh Ong

2015-03-01

This study was aimed at validating the simplified Chinese version of the Multidimensional Scale of Perceived Support (MSPSS-SCV) among a group of medical and dental students in University Malaya. Two hundred and two students who took part in this study were given the MSPSS-SCV, the Medical Outcome Study social support survey, the Malay version of the Beck Depression Inventory, the Malay version of the General Health Questionnaire, and the English version of the MSPSS. After 1 week, these students were again required to complete the MSPSS-SCV but with the item sequences shuffled. This scale displayed excellent internal consistency (Cronbach's α = .924), high test-retest reliability (.71), parallel form reliability (.92; Spearman's ρ, P students. It could therefore be used as a simple screening tool among young educated Malaysian adolescents. © 2013 APJPH.

Introduction to the reliability and safety of mechanical supports. Einfuehrung in die Sicherheit und Zuverlaessigkeit von Tragwerken

Energy Technology Data Exchange (ETDEWEB)

Schueller, G I

1981-01-01

The book is divided into an introduction and three sections. The first section deals with the elements of statistics and the theory of probability. This section, providing also simple examples of application, is intended for such readers which up to now are not or only little familiar with the probabilistic philosophy and its application to problems of civil engineering. This section also is suited as an accompanying or supplementary text for an introductory lecture in this field and, as a matter of fact, is used as such by the author at Munich Technical University. The second section especially deals with the application of these methods to supporting structures, i.e. with the introduction to safety theory and reliability assessment of buildings. This section also treats the essential concepts and with the knowledge in probability theory and statistics already at hand or gained by studying the first section is easily understandable. Here also references are given concerning the elements of establishing standards and codes on the bases of probability theory. The last section deals with practical applications of safety reliability theory prepared in the preceeding section. This is done using engineering structures loaded by wind, seismic and wave forces.

The importance of the reliability study for the safety operation of chemical plants. Application in heavy water plants

International Nuclear Information System (INIS)

Dumitrescu, Maria; Lazar, Roxana Elena; Preda, Irina Aida; Stefanescu, Ioan

1999-01-01

Heavy water production in Romania is based on H 2 O-H 2 S isotopic exchange process followed by vacuum isotopic distillation. The heavy water plant are complex chemical systems, characterized by an ensemble of static and dynamic equipment, AMC components, enclosures. Such equipment must have a high degree of reliability, a maximum safety in technological operation and a high availability index. Safety, reliable and economical operation heavy water plants need to maintain the systems and the components at adequate levels of reliability. The paper is a synthesis of the qualitative and quantitative assessment reliability studies for heavy water plants. The operation analysis on subsystems, each subsystems being a well-defined unit, is required by the plant complexity. For each component the reliability indicators were estimated by parametric and non-parametric methods based on the plant operation data. Also, the reliability qualitative and quantitative assessment was done using the fault tree technique. For the dual temperature isotopic exchange plants the results indicate an increase of the MTBF after the first years of operation, illustrating both the operation experience increasing and maintenance improvement. Also a high degree of availability was illustrated by the reliability studies of the vacuum distillation plant. The establishment of the reliability characteristics for heavy water plant represents an important step, a guide for highlighting the elements and process liable to failure being at the same time a planning modality to correlate the control times with the maintenance operations. This is the way to minimise maintenance, control and costs. The main purpose of the reliability study was the safety increase of the plant operation and the support for decision making. (authors)

An analysis of reliability and validity of the papilla index score of implant-supported single crowns of maxillary central incisors

DEFF Research Database (Denmark)

Peng, Min; Fei, Wei; Hosseini, Mandana

2012-01-01

Objectives: To test the reliability and validity of the papilla index scores of the implant-supported single crowns (ISSCs) of maxillary central incisors. Materials and Methods: Twenty-five patients with 25 ISSCs were included. Two prosthodontists evaluated the papilla index score (PIS) of three...... inter-observer agreement. The PIS score demonstrated significant correlation to the corresponding PP value (rs=.567, p=.000). Conclusions: The feasibility, reliability and validity of the PIS made the parameter useful for quality control of the pri-implant soft tissue of ISSCs....... fill percent (PP) was calculated. The validity of PIS was tested against the corresponding papilla fill percent (PP) by using the Spearman correlation analysis. Results: The intra-observer agreement was >70% in 4/5 and >50% in all observations, the pooled Cohen’s ¿ was 0.64 and 0.70 for two observers...

Software reliability growth model for safety systems of nuclear reactor

International Nuclear Information System (INIS)

Thirugnana Murthy, D.; Murali, N.; Sridevi, T.; Satya Murty, S.A.V.; Velusamy, K.

2014-01-01

The demand for complex software systems has increased more rapidly than the ability to design, implement, test, and maintain them, and the reliability of software systems has become a major concern for our, modern society.Software failures have impaired several high visibility programs in space, telecommunications, defense and health industries. Besides the costs involved, it setback the projects. The ways of quantifying it and using it for improvement and control of the software development and maintenance process. This paper discusses need for systematic approaches for measuring and assuring software reliability which is a major share of project development resources. It covers the reliability models with the concern on 'Reliability Growth'. It includes data collection on reliability, statistical estimation and prediction, metrics and attributes of product architecture, design, software development, and the operational environment. Besides its use for operational decisions like deployment, it includes guiding software architecture, development, testing and verification and validation. (author)

Reliability measures for indexed semi-Markov chains applied to wind energy production

International Nuclear Information System (INIS)

D'Amico, Guglielmo; Petroni, Filippo; Prattico, Flavio

2015-01-01

The computation of the dependability measures is a crucial point in many engineering problems as well as in the planning and development of a wind farm. In this paper we address the issue of energy production by wind turbines by using an indexed semi-Markov chain as a model of wind speed. We present the mathematical model, the data and technical characteristics of a commercial wind turbine (Aircon HAWT-10kW). We show how to compute some of the main dependability measures such as reliability, availability and maintainability functions. We compare the results of the model with real energy production obtained from data available in the Lastem station (Italy) and sampled every 10 min. - Highlights: • Semi-Markov models. • Time series generation of wind speed. • Computation of availability, reliability and maintainability.

Fuel reliability experience in Finland

International Nuclear Information System (INIS)

Kekkonen, L.

2015-01-01

Four nuclear reactors have operated in Finland now for 35-38 years. The two VVER-440 units at Loviisa Nuclear Power Plant are operated by Fortum and two BWR’s in Olkiluoto are operated by Teollisuuden Voima Oyj (TVO). The fuel reliability experience of the four reactors operating currently in Finland has been very good and the fuel failure rates have been very low. Systematic inspection of spent fuel assemblies, and especially all failed assemblies, is a good practice that is employed in Finland in order to improve fuel reliability and operational safety. Investigation of the root cause of fuel failures is important in developing ways to prevent similar failures in the future. The operational and fuel reliability experience at the Loviisa Nuclear Power Plant has been reported also earlier in the international seminars on WWER Fuel Performance, Modelling and Experimental Support. In this paper the information on fuel reliability experience at Loviisa NPP is updated and also a short summary of the fuel reliability experience at Olkiluoto NPP is given. Keywords: VVER-440, fuel reliability, operational experience, poolside inspections, fuel failure identification. (author)

Maintaining scale as a realiable computational system for criticality safety analysis

International Nuclear Information System (INIS)

Bowmann, S.M.; Parks, C.V.; Martin, S.K.

1995-01-01

Accurate and reliable computational methods are essential for nuclear criticality safety analyses. The SCALE (Standardized Computer Analyses for Licensing Evaluation) computer code system was originally developed at Oak Ridge National Laboratory (ORNL) to enable users to easily set up and perform criticality safety analyses, as well as shielding, depletion, and heat transfer analyses. Over the fifteen-year life of SCALE, the mainstay of the system has been the criticality safety analysis sequences that have featured the KENO-IV and KENO-V.A Monte Carlo codes and the XSDRNPM one-dimensional discrete-ordinates code. The criticality safety analysis sequences provide automated material and problem-dependent resonance processing for each criticality calculation. This report details configuration management which is essential because SCALE consists of more than 25 computer codes (referred to as modules) that share libraries of commonly used subroutines. Changes to a single subroutine in some cases affect almost every module in SCALE exclamation point Controlled access to program source and executables and accurate documentation of modifications are essential to maintaining SCALE as a reliable code system. The modules and subroutine libraries in SCALE are programmed by a staff of approximately ten Code Managers. The SCALE Software Coordinator maintains the SCALE system and is the only person who modifies the production source, executables, and data libraries. All modifications must be authorized by the SCALE Project Leader prior to implementation

Performance and reliability of TPE-2 device with pulsed high power source

International Nuclear Information System (INIS)

Sato, Y.; Takeda, S.; Kiyama, S.

1987-01-01

The performance and the reliability of TPE-2 device with pulsed high power sources are described. To obtain the stable high beta plasma, the reproducibility and the reliability of the pulsed power sources must be maintained. A new power crowbar system with high efficiency and the switches with low jitter time are adopted to the bank system. A monitor system which always watches the operational states of the switches is developed too, and applied for the fast rising capacitor banks of TPE-2 device. The reliable operation for the bank has been realized, based on the data of switch monitor system

Laboratory Information Management System Chain of Custody: Reliability and Security

Science.gov (United States)

Tomlinson, J. J.; Elliott-Smith, W.; Radosta, T.

2006-01-01

A chain of custody (COC) is required in many laboratories that handle forensics, drugs of abuse, environmental, clinical, and DNA testing, as well as other laboratories that want to assure reliability of reported results. Maintaining a dependable COC can be laborious, but with the recent establishment of the criteria for electronic records and signatures by US regulatory agencies, laboratory information management systems (LIMSs) are now being developed to fully automate COCs. The extent of automation and of data reliability can vary, and FDA- and EPA-compliant electronic signatures and system security are rare. PMID:17671623

Reliability prediction of engineering systems with competing failure modes due to component degradation

International Nuclear Information System (INIS)

Son, Young Kap

2011-01-01

Reliability of an engineering system depends on two reliability metrics: the mechanical reliability, considering component failures, that a functional system topology is maintained and the performance reliability of adequate system performance in each functional configuration. Component degradation explains not only the component aging processes leading to failure in function, but also system performance change over time. Multiple competing failure modes for systems with degrading components in terms of system functionality and system performance are considered in this paper with the assumption that system functionality is not independent of system performance. To reduce errors in system reliability prediction, this paper tries to extend system performance reliability prediction methods in open literature through combining system mechanical reliability from component reliabilities and system performance reliability. The extended reliability prediction method provides a useful way to compare designs as well as to determine effective maintenance policy for efficient reliability growth. Application of the method to an electro-mechanical system, as an illustrative example, is explained in detail, and the prediction results are discussed. Both mechanical reliability and performance reliability are compared to total system reliability in terms of reliability prediction errors

Crisis Reliability Indicators Supporting Emergency Services (CRISES): A Framework for Developing Performance Measures for Behavioral Health Crisis and Psychiatric Emergency Programs.

Science.gov (United States)

Balfour, Margaret E; Tanner, Kathleen; Jurica, Paul J; Rhoads, Richard; Carson, Chris A

2016-01-01

Crisis and emergency psychiatric services are an integral part of the healthcare system, yet there are no standardized measures for programs providing these services. We developed the Crisis Reliability Indicators Supporting Emergency Services (CRISES) framework to create measures that inform internal performance improvement initiatives and allow comparison across programs. The framework consists of two components-the CRISES domains (timely, safe, accessible, least-restrictive, effective, consumer/family centered, and partnership) and the measures supporting each domain. The CRISES framework provides a foundation for development of standardized measures for the crisis field. This will become increasingly important as pay-for-performance initiatives expand with healthcare reform.

Research and design of module supporting and rotary device in hot cell

International Nuclear Information System (INIS)

Wu Wenguang; Song Changfei; Chen Mingchi

2013-01-01

Background: This paper introduced a device for tandem accelerator project, designed for the radioactive target source module maintaining and testing. Purpose: The module is required to be lifting, rotary and precise orientation in technology. Methods: We designed the structure of rotary drum, supporting drum and screw lifting device to achieve the function. In circumference, we adopt the project with electro-motion cursory locate, hand-motion precise locate, sensor location detect and cylinder locate pin, the measure is safe and trustiness. Results: Via experimentation, all technology targets are fulfilled, and the rationality and reliability of the device has been validated. Conclusions: The successful development of this device provides a good direction and reference for radioactive areas such as accelerator, hot cell, reactor etc., and can be adapted to its capability of long-distance shield operating, maintaining or testing. (authors)

Proceedings of the workshop on reliability data collection

International Nuclear Information System (INIS)

1999-01-01

The main purpose of the Workshop was to provide a forum for exchanging information and experience on Reliability Data Collection and analysis to support Living Probabilistic Safety Assessments (LPSA). The Workshop is divided into four sessions which titles are: Session 1: Reliability Data - Database Systems (3 papers), Session 2: Reliability Data Collection for PSA (5 papers), Session 3: NPP Data Collection (3 papers), Session 4: Reliability Data Assessment (Part 1: General - 2 papers; Part 2: CCF - 2 papers; Part 3: Reactor Protection Systems / External Event Data - 2 papers; Part 4: Human Errors - 2 papers)

System reliability, performance and trust in adaptable automation.

Science.gov (United States)

Chavaillaz, Alain; Wastell, David; Sauer, Jürgen

2016-01-01

The present study examined the effects of reduced system reliability on operator performance and automation management in an adaptable automation environment. 39 operators were randomly assigned to one of three experimental groups: low (60%), medium (80%), and high (100%) reliability of automation support. The support system provided five incremental levels of automation which operators could freely select according to their needs. After 3 h of training on a simulated process control task (AutoCAMS) in which the automation worked infallibly, operator performance and automation management were measured during a 2.5-h testing session. Trust and workload were also assessed through questionnaires. Results showed that although reduced system reliability resulted in lower levels of trust towards automation, there were no corresponding differences in the operators' reliance on automation. While operators showed overall a noteworthy ability to cope with automation failure, there were, however, decrements in diagnostic speed and prospective memory with lower reliability. Copyright © 2015. Published by Elsevier Ltd.

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)

Human factors review of power plant maintainability

International Nuclear Information System (INIS)

Seminara, J.L.; Parsons, S.O.; Schmidt, W.J.; Gonzalez, W.R.; Dove, L.E.

1980-10-01

Human factors engineering is an interdisciplinary science and technology concerned with shaping the design of machines, facilities, and operational environments to promote safe, efficient, and reliable performance on the part of operators and maintainers of equipment systems. The human factors aspects of five nuclear power plants and four fossil fuel plants were evaluated using such methods as a checklist guided observation system, structured interviews with maintenance personnel, direct observations of maintenance tasks, reviews of procedures, and analyses of maintenance errors or accidents by means of the critical incident technique. The study revealed a wide variety of human factors problem areas, most of which are extensively photodocumented. The study recommends that a more systematic and formal approach be adopted to ensure that future power plants are human engineered to the needs of maintenance personnel

Development of a Reliability Program approach to assuring operational nuclear safety

International Nuclear Information System (INIS)

Mueller, C.J.; Bezella, W.A.

1985-01-01

A Reliability Program (RP) model based on proven reliability techniques used in other high technology industries is being formulated for potential application in the nuclear power industry. Research findings are discussed. The reliability methods employed under NASA and military direction, commercial airline and related FAA programs were surveyed with several reliability concepts (e.g., quantitative reliability goals, reliability centered maintenance) appearing to be directly transferable. Other tasks in the RP development effort involved the benchmarking and evaluation of the existing nuclear regulations and practices relevant to safety/reliability integration. A review of current risk-dominant issues was also conducted using results from existing probabilistic risk assessment studies. The ongoing RP development tasks have concentrated on defining a RP for the operating phase of a nuclear plant's lifecycle. The RP approach incorporates safety systems risk/reliability analysis and performance monitoring activities with dedicated tasks that integrate these activities with operating, surveillance, and maintenance of the plant. The detection, root-cause evaluation and before-the-fact correction of incipient or actual systems failures as a mechanism for maintaining plant safety is a major objective of the RP

Reliable Fault Classification of Induction Motors Using Texture Feature Extraction and a Multiclass Support Vector Machine

Directory of Open Access Journals (Sweden)

Jia Uddin

2014-01-01

Full Text Available This paper proposes a method for the reliable fault detection and classification of induction motors using two-dimensional (2D texture features and a multiclass support vector machine (MCSVM. The proposed model first converts time-domain vibration signals to 2D gray images, resulting in texture patterns (or repetitive patterns, and extracts these texture features by generating the dominant neighborhood structure (DNS map. The principal component analysis (PCA is then used for the purpose of dimensionality reduction of the high-dimensional feature vector including the extracted texture features due to the fact that the high-dimensional feature vector can degrade classification performance, and this paper configures an effective feature vector including discriminative fault features for diagnosis. Finally, the proposed approach utilizes the one-against-all (OAA multiclass support vector machines (MCSVMs to identify induction motor failures. In this study, the Gaussian radial basis function kernel cooperates with OAA MCSVMs to deal with nonlinear fault features. Experimental results demonstrate that the proposed approach outperforms three state-of-the-art fault diagnosis algorithms in terms of fault classification accuracy, yielding an average classification accuracy of 100% even in noisy environments.

Reliability analysis of the reactor protection system with fault diagnosis

International Nuclear Information System (INIS)

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

2004-01-01

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

Using Vector Projection Method to evaluate maintainability of mechanical system in design review

International Nuclear Information System (INIS)

Chen Lu; Cai Jianguo

2003-01-01

Maintainability of a mechanical system is one of the system design parameters that has a great impact in terms of ease of maintenance. In this article, based on the definition of the terms of maintenance and maintainability, an important tool of Design for Maintenance is developed as a way to improve maintainability through design. A set of standard and organized guidelines is provided and maintainability factors in terms of physical design, logistics support and ergonomics are identified. As a specific application of design review, a methodology so called Vector Projection Method is developed to evaluate the maintainability of the mechanical system. Lastly, an example is discussed

Reliability Centered Maintenance - Methodologies

Science.gov (United States)

Kammerer, Catherine C.

2009-01-01

Journal article about Reliability Centered Maintenance (RCM) methodologies used by United Space Alliance, LLC (USA) in support of the Space Shuttle Program at Kennedy Space Center. The USA Reliability Centered Maintenance program differs from traditional RCM programs because various methodologies are utilized to take advantage of their respective strengths for each application. Based on operational experience, USA has customized the traditional RCM methodology into a streamlined lean logic path and has implemented the use of statistical tools to drive the process. USA RCM has integrated many of the L6S tools into both RCM methodologies. The tools utilized in the Measure, Analyze, and Improve phases of a Lean Six Sigma project lend themselves to application in the RCM process. All USA RCM methodologies meet the requirements defined in SAE JA 1011, Evaluation Criteria for Reliability-Centered Maintenance (RCM) Processes. The proposed article explores these methodologies.

Guarantee of reliability of devices complexes for plastic tube welding

International Nuclear Information System (INIS)

Voskresenskij, L.A.; Zajtsev, A.I.; Nelyubov, V.I.; Fedorov, M.A.

1988-01-01

Results of calculations and experimental studies on providing reliability of complex for plastic tube welding are presented. Choice of reliability indeces and standards is based. Reliability levels of components are determined. The most waded details are calculated. It is shown that they meet the reqrurements of strength and reliability. Service life tests supported the correct choice of springs. Recommendations on elevating reliability are given. Directions of further developments are shown. 8 refs.; 2 figs.; 1 tab

Maintainability allocation

International Nuclear Information System (INIS)

Guyot, Christian.

1980-06-01

The author gives the general lines of a method for the allocation and for the evaluation of maintainability of complex systems which is to be developed during the conference. The maintainability objective is supposed to be formulated under the form of a mean time to repair (M.T.T.R.) [fr

Maintaining and improving the control and safety systems for the Electromagnetic Calorimeter of the CMS experiment

CERN Document Server

Di Calafiori, Diogo Raphael; Dissertori, Günther; Holme, Oliver; Jovanovic, Dragoslav; Lustermann, Werner; Zelepoukine, Serguei

2012-01-01

This paper presents the current architecture of the control and safety systems designed and implemented for the Electromagnetic Calorimeter (ECAL) of the Compact Muon Solenoid (CMS) experiment at the Large Hadron Collider (LHC). An evaluation of system performance during all CMS physics data taking periods is reported, with emphasis on how software and hardware solutions are used to overcome limitations, whilst maintaining and improving reliability and robustness. The outcomes of the CMS ECAL Detector Control System (DCS) Software Analysis Project were a fundamental step towards the integration of all control system applications and the consequent piece-by-piece software improvements allowed a smooth transition to the latest revision of the system. The ongoing task of keeping the system in-line with new hardware technologies and software platforms specified by the CMS DCS Group is discussed. The structure of the comprehensive support service with detailed incident logging is presented in addition to a complet...

A taxonomy for human reliability analysis

International Nuclear Information System (INIS)

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

1984-01-01

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

Mission Reliability Estimation for Repairable Robot Teams

Science.gov (United States)

Trebi-Ollennu, Ashitey; Dolan, John; Stancliff, Stephen

2010-01-01

A mission reliability estimation method has been designed to translate mission requirements into choices of robot modules in order to configure a multi-robot team to have high reliability at minimal cost. In order to build cost-effective robot teams for long-term missions, one must be able to compare alternative design paradigms in a principled way by comparing the reliability of different robot models and robot team configurations. Core modules have been created including: a probabilistic module with reliability-cost characteristics, a method for combining the characteristics of multiple modules to determine an overall reliability-cost characteristic, and a method for the generation of legitimate module combinations based on mission specifications and the selection of the best of the resulting combinations from a cost-reliability standpoint. The developed methodology can be used to predict the probability of a mission being completed, given information about the components used to build the robots, as well as information about the mission tasks. In the research for this innovation, sample robot missions were examined and compared to the performance of robot teams with different numbers of robots and different numbers of spare components. Data that a mission designer would need was factored in, such as whether it would be better to have a spare robot versus an equivalent number of spare parts, or if mission cost can be reduced while maintaining reliability using spares. This analytical model was applied to an example robot mission, examining the cost-reliability tradeoffs among different team configurations. Particularly scrutinized were teams using either redundancy (spare robots) or repairability (spare components). Using conservative estimates of the cost-reliability relationship, results show that it is possible to significantly reduce the cost of a robotic mission by using cheaper, lower-reliability components and providing spares. This suggests that the

Classifier Fusion With Contextual Reliability Evaluation.

Science.gov (United States)

Liu, Zhunga; Pan, Quan; Dezert, Jean; Han, Jun-Wei; He, You

2018-05-01

Classifier fusion is an efficient strategy to improve the classification performance for the complex pattern recognition problem. In practice, the multiple classifiers to combine can have different reliabilities and the proper reliability evaluation plays an important role in the fusion process for getting the best classification performance. We propose a new method for classifier fusion with contextual reliability evaluation (CF-CRE) based on inner reliability and relative reliability concepts. The inner reliability, represented by a matrix, characterizes the probability of the object belonging to one class when it is classified to another class. The elements of this matrix are estimated from the -nearest neighbors of the object. A cautious discounting rule is developed under belief functions framework to revise the classification result according to the inner reliability. The relative reliability is evaluated based on a new incompatibility measure which allows to reduce the level of conflict between the classifiers by applying the classical evidence discounting rule to each classifier before their combination. The inner reliability and relative reliability capture different aspects of the classification reliability. The discounted classification results are combined with Dempster-Shafer's rule for the final class decision making support. The performance of CF-CRE have been evaluated and compared with those of main classical fusion methods using real data sets. The experimental results show that CF-CRE can produce substantially higher accuracy than other fusion methods in general. Moreover, CF-CRE is robust to the changes of the number of nearest neighbors chosen for estimating the reliability matrix, which is appealing for the applications.

Theory and practice of quality and reliability engineering in Asia industry

CERN Document Server

Goh, Thong

2017-01-01

This book discusses the application of quality and reliability engineering in Asian industries, and offers information for multinational companies (MNC) looking to transfer some of their operation and manufacturing capabilities to Asia and at the same time maintain high levels of reliability and quality. It is also provides small and medium enterprises (SME) in Asia with insights into producing high-quality and reliable products. It mainly comprises peer-reviewed papers that were presented at the Asian Network for Quality (ANQ) Congress 2014 held in Singapore (August, 2014), which provides a platform for companies, especially those within Asia where rapid changes and growth in manufacturing are taking place, to present their quality and reliability practices. The book presents practical demonstrations of how quality and reliability methodologies can be modified for the unique Asian market, and as such is a valuable resource for students, academics, professionals and practitioners in the field of quality and r...

Research on reliability management systems for Nuclear Power Plant

International Nuclear Information System (INIS)

Maki, Nobuo

2000-01-01

Investigation on a reliability management system for Nuclear Power Plants (NPPs) has been performed on national and international archived documents as well as on current status of studies at Idaho National Engineering and Environmental Laboratory (INEEL), US NPPs (McGuire, Seabrook), a French NPP (St. Laurent-des-Eaux), Japan Atomic Energy Research Institute (JAERI), Central Research Institute of Electric Power Industries (CRIEPI), and power plant manufacturers in Japan. As a result of the investigation, the following points were identified: (i) A reliability management system is composed of a maintenance management system to inclusively manage maintenance data, and an anomalies information and reliability data management system to extract data from maintenance results stored in the maintenance management system and construct a reliability database. (ii) The maintenance management system, which is widely-used among NPPs in the US and Europe, is an indispensable system for the increase of maintenance reliability. (iii) Maintenance management methods utilizing reliability data like Reliability Centered Maintenance are applied for NPP maintenance in the US and Europe, and contributing to cost saving. Maintenance templates are effective in the application process. In addition, the following points were proposed on the design of the system: (i) A detailed database on specifications of facilities and components is necessary for the effective use of the system. (ii) A demand database is indispensable for the application of the methods. (iii) Full-time database managers are important to maintain the quality of the reliability data. (author)

FORMENTOR real-time decision support for risk management

International Nuclear Information System (INIS)

Pennings, R.; Gerlinger, G.; Ponamale, M.

1995-01-01

The supervision of complex industrial processes, such as in the chemical, nuclear or aerospace industries, is a difficult task. The FORMENTOR methodology allows the development of supervision support systems to aid operations in their tasks, especially when dealing with perturbations and hazardous situations. A FORMENTOR system presents a synthetic plant-wide view of the current situation, diagnoses the underlying causes of perturbations, predicts possible future evolutions and proposes remedial actions. For this the methodology integrates models, techniques and tools from four domains namely artificial intelligence, safety analysis, real-time computing and ergonomics. The methodological approach provides firm control over the development process while meeting the quality and technical requirements of the client; furthermore it ensures the reliability and maintainability of the obtained system

Reliable Autonomous Surface Mobility (RASM) in Support of Human Exploration, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — ProtoInnovations, LLC and Carnegie Mellon University have formed a partnership to commercially develop rover-autonomy technologies into Reliable Autonomous Surface...

Development and psychometric evaluation of supportive leadership scales.

Science.gov (United States)

McGilton, Katherine S

2003-12-01

The purpose of this study was to develop and evaluate the psychometric properties of 2 supportive leadership scales, the Charge Nurse Support Scale and the Unit Manager Support Scale, designed for long-term-care environments. These 6-item self-report scales were administered to 70 nursing staff and their internal consistency reliability, test-retest reliability, content validity, factor structure, and construct validity investigated. Content validity was established with the assistance of experts. Both scales were deemed reliable. As hypothesized, a significant relationship was found between the measure of how nursing staff related to residents and measures of charge nurses' supportive behaviours (r = .42, p = .05). Reliable and valid measures of supportive leadership could be developed for use in identifying the quality of support provided to staff in long-term-care environments.

Software Reliability Issues Concerning Large and Safety Critical Software Systems

Science.gov (United States)

Kamel, Khaled; Brown, Barbara

1996-01-01

This research was undertaken to provide NASA with a survey of state-of-the-art techniques using in industrial and academia to provide safe, reliable, and maintainable software to drive large systems. Such systems must match the complexity and strict safety requirements of NASA's shuttle system. In particular, the Launch Processing System (LPS) is being considered for replacement. The LPS is responsible for monitoring and commanding the shuttle during test, repair, and launch phases. NASA built this system in the 1970's using mostly hardware techniques to provide for increased reliability, but it did so often using custom-built equipment, which has not been able to keep up with current technologies. This report surveys the major techniques used in industry and academia to ensure reliability in large and critical computer systems.

Interim reliability evaluation program, Browns Ferry fault trees

International Nuclear Information System (INIS)

Stewart, M.E.

1981-01-01

An abbreviated fault tree method is used to evaluate and model Browns Ferry systems in the Interim Reliability Evaluation programs, simplifying the recording and displaying of events, yet maintaining the system of identifying faults. The level of investigation is not changed. The analytical thought process inherent in the conventional method is not compromised. But the abbreviated method takes less time, and the fault modes are much more visible

OREDA offshore and onshore reliability data volume 1 - topside equipment

CERN Document Server

OREDA

2015-01-01

This handbook presents high quality reliability data for offshore equipment collected during phase VI to IX (project period 2000 – 2009) of the OREDA project. The intention of the handbook is to provide both quantitative and qualitative information as a basis for Performance Forecasting or RAMS (Reliability, Availability, Maintainability and Safety) analyses. Volume 1 is about Topside Equipment. Compared to earlier editions, there are only minor changes in the reliability data presentation. To obtain a reasonable population for presenting reliability data for topside equipment in the 2015 edition, some data from phases VI and VII already issued in the previous 2009 handbook (5th edition) have also been included. The 2015 topside volume is divided into two parts. Part I describes the OREDA project, different data collection phases and the estimation procedures used to generate the data tables presented in Part II of the handbook. Topside data are in general not covering the whole lifetime of equipment, but ...

Evaluation of the reliability concerning the identification of human factors as contributing factors by a computer supported event analysis (CEA)

International Nuclear Information System (INIS)

Wilpert, B.; Maimer, H.; Loroff, C.

2000-01-01

The project's objectives are the evaluation of the reliability concerning the identification of Human Factors as contributing factors by a computer supported event analysis (CEA). CEA is a computer version of SOL (Safety through Organizational Learning). Parts of the first step were interviews with experts from the nuclear power industry and the evaluation of existing computer supported event analysis methods. This information was combined to a requirement profile for the CEA software. The next step contained the implementation of the software in an iterative process of evaluation. The completion of this project was the testing of the CEA software. As a result the testing demonstrated that it is possible to identify contributing factors with CEA validly. In addition, CEA received a very positive feedback from the experts. (orig.) [de

Impact of Agile Software Development Model on Software Maintainability

Science.gov (United States)

Gawali, Ajay R.

2012-01-01

Software maintenance and support costs account for up to 60% of the overall software life cycle cost and often burdens tightly budgeted information technology (IT) organizations. Agile software development approach delivers business value early, but implications on software maintainability are still unknown. The purpose of this quantitative study…

Reliability improvement through alternative designs-A case study

International Nuclear Information System (INIS)

Kumar, Saurabh; Chattopadhyay, Gopi; Kumar, Uday

2007-01-01

In today's competitive world, reliability of equipment is extremely important to maintain quality and delivery deadlines. This is achieved by using proper maintenance and design changes for unreliable subsystems and components of a complex system. It is significant to develop a strategy for maintenance, replacement and design changes related to those subsystems and components. An analysis of down time along with causes is essential to identify the unreliable components and subsystems. This paper presents an analysis of failure data of solenoid coils of automatic internal grinding machine used in a bearing manufacturing plant. It analyses various replacement and change of design options such as introduction of pneumatic system in place of electromagnetic solenoids for improvement of reliability of the plunger movement mechanism

Reliability of infrared thermometric measurements of skin temperature in the hand.

Science.gov (United States)

Packham, Tara L; Fok, Diana; Frederiksen, Karen; Thabane, Lehana; Buckley, Norman

2012-01-01

Clinical measurement study. Skin temperature asymmetries (STAs) are used in the diagnosis of complex regional pain syndrome (CRPS), but little evidence exists for reliability of the equipment and methods. This study examined the reliability of an inexpensive infrared (IR) thermometer and measurement points in the hand for the study of STA. ST was measured three times at five points on both hands with an IR thermometer by two raters in 20 volunteers (12 normals and 8 CRPS). ST measurement results using IR thermometers support inter-rater reliability: intraclass correlation coefficient (ICC) estimate for single measures 0.80; all ST measurement points were also highly reliable (ICC single measures, 0.83-0.91). The equipment demonstrated excellent reliability, with little difference in the reliability of the five measurement sites. These preliminary findings support their use in future CRPS research. Not applicable. Copyright © 2012 Hanley & Belfus. Published by Elsevier Inc. All rights reserved.

Supporting farmers in maintaining and selecting seeds of local varieties

NARCIS (Netherlands)

Almekinders, C.J.M.; Louwaars, N.P.

2009-01-01

This book addresses strategies and approaches through which professionals can support informal seed supply, and link these with the conservation and use of the huge genetic resource base of crops and local varieties. The aim of all the strategies, case studies and reflections on experiences

Fatigue Reliability of Offshore Wind Turbine Systems

DEFF Research Database (Denmark)

Marquez-Dominguez, Sergio; Sørensen, John Dalsgaard

2012-01-01

of appropriate partial safety factors / fatigue design factors (FDF) for steel substructures of offshore wind turbines (OWTs). The fatigue life is modeled by the SN approach. Design and limit state equations are established based on the accumulated fatigue damage. The acceptable reliability level for optimal...... fatigue design of OWTs is discussed and results for reliability assessment of typical fatigue critical design of offshore steel support structures are presented....

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

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

Seeking high reliability in primary care: Leadership, tools, and organization.

Science.gov (United States)

Weaver, Robert R

2015-01-01

Leaders in health care increasingly recognize that improving health care quality and safety requires developing an organizational culture that fosters high reliability and continuous process improvement. For various reasons, a reliability-seeking culture is lacking in most health care settings. Developing a reliability-seeking culture requires leaders' sustained commitment to reliability principles using key mechanisms to embed those principles widely in the organization. The aim of this study was to examine how key mechanisms used by a primary care practice (PCP) might foster a reliability-seeking, system-oriented organizational culture. A case study approach was used to investigate the PCP's reliability culture. The study examined four cultural artifacts used to embed reliability-seeking principles across the organization: leadership statements, decision support tools, and two organizational processes. To decipher their effects on reliability, the study relied on observations of work patterns and the tools' use, interactions during morning huddles and process improvement meetings, interviews with clinical and office staff, and a "collective mindfulness" questionnaire. The five reliability principles framed the data analysis. Leadership statements articulated principles that oriented the PCP toward a reliability-seeking culture of care. Reliability principles became embedded in the everyday discourse and actions through the use of "problem knowledge coupler" decision support tools and daily "huddles." Practitioners and staff were encouraged to report unexpected events or close calls that arose and which often initiated a formal "process change" used to adjust routines and prevent adverse events from recurring. Activities that foster reliable patient care became part of the taken-for-granted routine at the PCP. The analysis illustrates the role leadership, tools, and organizational processes play in developing and embedding a reliable-seeking culture across an

Airline experience with reliability-centered maintenance

International Nuclear Information System (INIS)

Matteson, T.D.

1985-01-01

Reliability-Centered Maintenance is a process for developing preventive maintenance programs. Its concepts evolved from the post WWII experience of the airline community. Its genesis was in a paper by F. Stanley Nowlan and Thomas D. Matteson of United Airlines for the American Institute of Aeronautics and Astronautics in 1967. Its first application was to the Boeing 747. It has subsequently been adopted by the FAA and the Department of Defense and applied to many new transport and military aircraft. Its objective is applicable and effective preventive maintenance and it has proven to be a highly effective replacement for the prior intuitive processes for selective preventive maintenance tasks. It focuses on system functions, functional failures, then dominant failure modes and effects. It then uses a decision tree to classify failure criticality and identify applicable and effective tasks. The result is a program focused on maintaining inherent safety and reliability at minimum cost. (orig.)

Airline experience with reliability-centered maintenance

Energy Technology Data Exchange (ETDEWEB)

Matteson, T.D.

1985-11-01

Reliability-Centered Maintenance is a process for developing preventive maintenance programs. Its concepts evolved from the post WWII experience of the airline community. Its genesis was in a paper by F. Stanley Nowlan and Thomas D. Matteson of United Airlines for the American Institute of Aeronautics and Astronautics in 1967. Its first application was to the Boeing 747. It has subsequently been adopted by the FAA and the Department of Defense and applied to many new transport and military aircraft. Its objective is applicable and effective preventive maintenance and it has proven to be a highly effective replacement for the prior intuitive processes for selective preventive maintenance tasks. It focuses on system functions, functional failures, then dominant failure modes and effects. It then uses a decision tree to classify failure criticality and identify applicable and effective tasks. The result is a program focused on maintaining inherent safety and reliability at minimum cost. (orig.).

Reliability of microprocessor-based relay protection devices: Myths and reality

Directory of Open Access Journals (Sweden)

Gurevich Vladimir

2009-01-01

Full Text Available The article examines four basic theses about the ostensibly extremely high reliability of microprocessor-based relay protection (MP touted by supporters of MP. Through detailed analysis based on many references it is shown that the basis of these theses are widespread myths, and actually MP reliability is lower than the reliability of electromechanical and electronic protective relays on discrete components.

Ergonomics Contribution in Maintainability

Science.gov (United States)

Teymourian, Kiumars; Seneviratne, Dammika; Galar, Diego

2017-09-01

The objective of this paper is to describe an ergonomics contribution in maintainability. The economical designs, inputs and training helps to increase the maintainability indicators for industrial devices. This analysis can be helpful, among other cases, to compare systems, to achieve a better design regarding maintainability requirements, to improve this maintainability under specific industrial environment and to foresee maintainability problems due to eventual changes in a device operation conditions. With this purpose, this work first introduces the notion of ergonomics and human factors, maintainability and the implementation of assessment of human postures, including some important postures to perform maintenance activities. A simulation approach is used to identify the critical posture of the maintenance personnel and implements the defined postures with minimal loads on the personnel who use the equipment in a practical scenario. The simulation inputs are given to the designers to improve the workplace/equipment in order to high level of maintainability. Finally, the work concludes summarizing the more significant aspects and suggesting future research.

Maximally reliable Markov chains under energy constraints.

Science.gov (United States)

Escola, Sean; Eisele, Michael; Miller, Kenneth; Paninski, Liam

2009-07-01

Signal-to-noise ratios in physical systems can be significantly degraded if the outputs of the systems are highly variable. Biological processes for which highly stereotyped signal generations are necessary features appear to have reduced their signal variabilities by employing multiple processing steps. To better understand why this multistep cascade structure might be desirable, we prove that the reliability of a signal generated by a multistate system with no memory (i.e., a Markov chain) is maximal if and only if the system topology is such that the process steps irreversibly through each state, with transition rates chosen such that an equal fraction of the total signal is generated in each state. Furthermore, our result indicates that by increasing the number of states, it is possible to arbitrarily increase the reliability of the system. In a physical system, however, an energy cost is associated with maintaining irreversible transitions, and this cost increases with the number of such transitions (i.e., the number of states). Thus, an infinite-length chain, which would be perfectly reliable, is infeasible. To model the effects of energy demands on the maximally reliable solution, we numerically optimize the topology under two distinct energy functions that penalize either irreversible transitions or incommunicability between states, respectively. In both cases, the solutions are essentially irreversible linear chains, but with upper bounds on the number of states set by the amount of available energy. We therefore conclude that a physical system for which signal reliability is important should employ a linear architecture, with the number of states (and thus the reliability) determined by the intrinsic energy constraints of the system.

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

Artificial intelligence and the space station software support environment

Science.gov (United States)

Marlowe, Gilbert

1986-01-01

In a software system the size of the Space Station Software Support Environment (SSE), no one software development or implementation methodology is presently powerful enough to provide safe, reliable, maintainable, cost effective real time or near real time software. In an environment that must survive one of the most harsh and long life times, software must be produced that will perform as predicted, from the first time it is executed to the last. Many of the software challenges that will be faced will require strategies borrowed from Artificial Intelligence (AI). AI is the only development area mentioned as an example of a legitimate reason for a waiver from the overall requirement to use the Ada programming language for software development. The limits are defined of the applicability of the Ada language Ada Programming Support Environment (of which the SSE is a special case), and software engineering to AI solutions by describing a scenario that involves many facets of AI methodologies.

Seismic stops vs. snubbers, a reliable alternative

International Nuclear Information System (INIS)

Cloud, R.L.; Anderson, P.H.; Leung, J.S.M.

1988-01-01

The Seismic Stops methodology has been developed to provide a reliable alternative for providing seismic support to nuclear power plant piping. The concept is based on using rigid passive supports with large clearances. These gaps permit unrestrained thermal expansion while limiting excessive seismic displacements. This type of restraint has performed successfully in fossil fueled power plants. A simplified production analysis tool has been developed which evaluates the nonlinear piping response including the effect of the gapped supports. The methodology utilizes the response spectrum approach and has been incorporated into a piping analysis computer program RLCA-GAP. Full scale shake table tests of piping specimens were performed to provide test correlation with the developed methodology. Analyses using RLCA-GAP were in good agreement with test results. A sample piping system was evaluated using the Seismic Stops methodology to replace the existing snubbers with passive gapped supports. To provide further correlation data, the sample system was also evaluated using nonlinear time history analysis. The correlation comparisons showed RLCA-GAP to be a viable methodology and a reliable alternative for snubber optimization and elimination. (orig.)

Proof tests on reliability

International Nuclear Information System (INIS)

Mishima, Yoshitsugu

1983-01-01

In order to obtain public understanding on nuclear power plants, tests should be carried out to prove the reliability and safety of present LWR plants. For example, the aseismicity of nuclear power plants must be verified by using a large scale earthquake simulator. Reliability test began in fiscal 1975, and the proof tests on steam generators and on PWR support and flexure pins against stress corrosion cracking have already been completed, and the results have been internationally highly appreciated. The capacity factor of the nuclear power plant operation in Japan rose to 80% in the summer of 1983, and considering the period of regular inspection, it means the operation of almost full capacity. Japanese LWR technology has now risen to the top place in the world after having overcome the defects. The significance of the reliability test is to secure the functioning till the age limit is reached, to confirm the correct forecast of deteriorating process, to confirm the effectiveness of the remedy to defects and to confirm the accuracy of predicting the behavior of facilities. The reliability of nuclear valves, fuel assemblies, the heat affected zones in welding, reactor cooling pumps and electric instruments has been tested or is being tested. (Kako, I.)

The difference is more than floating: factors affecting breast cancer survivors' decisions to join and maintain participation in dragon boat teams and support groups.

Science.gov (United States)

McDonough, Meghan H; Patterson, Michelle C; Weisenbach, Beth B; Ullrich-French, Sarah; Sabiston, Catherine M

2018-03-09

Peer support can be helpful in rehabilitation from breast cancer, but participation in peer support groups is low. Groups that provide support opportunities in physical activity contexts are an attractive alternative for some survivors. This study examined survivors' reasons for joining and maintaining participation on a dragon boat team, along with perceptions of barriers and attractions to traditional peer support groups. Seventeen breast cancer survivors were interviewed on five occasions over their first two seasons of a newly formed dragon boating team to explore their perceptions of peer support groups and dragon boating. Data were inductively analyzed using thematic analysis. Categories surrounding physical, psychological, social and community features were identified with several themes emerging within each. Advantages of dragon boating included opportunities to get a combination of physical, psychosocial and community benefits; health improvement and behavior change; and obtaining social support without the focus being on cancer. Peer support groups were identified as having advantages for forming relationships and avoiding barriers associated with physical activity. While neither type of program meets all needs, practical considerations are identified for incorporating advantages of both programs to improve participation. Implications for rehabilitation Further understanding of perceptions, and attractions and challenges to taking part in group programs will inform development of accessible programs that target multiple rehabilitation needs. Physical activity can provide a positive, alternative focus that takes the emphasis off of cancer, which is more accessible to some survivors. Physical activity also provides opportunities to build relationships around a common, positive goal, which can be a foundation for providing support for coping with cancer.

Operator adaptation to changes in system reliability under adaptable automation.

Science.gov (United States)

Chavaillaz, Alain; Sauer, Juergen

2017-09-01

This experiment examined how operators coped with a change in system reliability between training and testing. Forty participants were trained for 3 h on a complex process control simulation modelling six levels of automation (LOA). In training, participants either experienced a high- (100%) or low-reliability system (50%). The impact of training experience on operator behaviour was examined during a 2.5 h testing session, in which participants either experienced a high- (100%) or low-reliability system (60%). The results showed that most operators did not often switch between LOA. Most chose an LOA that relieved them of most tasks but maintained their decision authority. Training experience did not have a strong impact on the outcome measures (e.g. performance, complacency). Low system reliability led to decreased performance and self-confidence. Furthermore, complacency was observed under high system reliability. Overall, the findings suggest benefits of adaptable automation because it accommodates different operator preferences for LOA. Practitioner Summary: The present research shows that operators can adapt to changes in system reliability between training and testing sessions. Furthermore, it provides evidence that each operator has his/her preferred automation level. Since this preference varies strongly between operators, adaptable automation seems to be suitable to accommodate these large differences.

Reliability Measure Model for Assistive Care Loop Framework Using Wireless Sensor Networks

Directory of Open Access Journals (Sweden)

Venki Balasubramanian

2010-01-01

Full Text Available Body area wireless sensor networks (BAWSNs are time-critical systems that rely on the collective data of a group of sensor nodes. Reliable data received at the sink is based on the collective data provided by all the source sensor nodes and not on individual data. Unlike conventional reliability, the definition of retransmission is inapplicable in a BAWSN and would only lead to an elapsed data arrival that is not acceptable for time-critical application. Time-driven applications require high data reliability to maintain detection and responses. Hence, the transmission reliability for the BAWSN should be based on the critical time. In this paper, we develop a theoretical model to measure a BAWSN's transmission reliability, based on the critical time. The proposed model is evaluated through simulation and then compared with the experimental results conducted in our existing Active Care Loop Framework (ACLF. We further show the effect of the sink buffer in transmission reliability after a detailed study of various other co-existing parameters.

Frequency-Control Reserves and Voltage Support from Electric Vehicles

DEFF Research Database (Denmark)

Pillai, Jayakrishnan Radhakrishna; Bak-Jensen, Birgitte

2013-01-01

The increasing penetration of variable wind power generation units and electricity consumption in power systems demands additional ancillary services for its reliable operation. The battery storages of electric vehicles are one of the substitute solutions for replacing conventional fossil......-fuelled generators to supply future grid support functions. The quick start and fast response characteristics of battery storages enable the electric vehicles to provide most of the power system auxiliary tasks. This chapter discusses key ancillary services that could be supplied by electric vehicles to maintain...... the system balance in power systems with high volumes of wind power generation. To analyse the applications and performance of electric vehicles in supplying active power balancing services, the case studies simulated in wind-power-dominated Danish power systems are also presented....

Advanced digital technology - improving nuclear power plant performance through maintainability

International Nuclear Information System (INIS)

Ford, J.L.; Senechal, R.R.; Altenhein, G.D.; Harvey, R.P.

1998-01-01

In today's energy sector there is ever increasing pressure on utilities to operate power plants at high capacity factors. To ensure nuclear power is competitive into the next century, it is imperative that strategic design improvements be made to enhance the performance of nuclear power plants. There are a number of factors that affect a nuclear power plant's performance; lifetime maintenance is one of the major contributors. The maturing of digital technology has afforded ABB the opportunity to make significant design improvements in the area of maintainability. In keeping with ABB's evolutionary advanced nuclear plant design approach, digital technology has systematically been incorporated into the control and protection systems of the most recent Korean nuclear units in operation and under construction. One example of this was the multi-functional design team approach that was utilized for the development of ABB's Digital Plant Protection System (DPPS). The design team consisted of engineers, maintenance technicians, procurement specialists and manufacturing personnel in order to provide a complete perspective on all facets of the design. The governing design goals of increased reliability and safety, simplicity of design, use of off-the-shelf products and reduced need for periodic surveillance testing were met with the selection of proven ABB-Advant Programmable Logic Controllers (PLCs) as the heart of the DPPS. The application of digital PLC technology allows operation for extended periods without requiring routine maintenance or re-calibration. A well documented commercial dedication program approved by the United States Nuclear Regulatory Commission (US NRC) as part of the System 80+ TM Advanced Light Water Reactor Design Certification Program, allowed the use of off-the shelf products in the design of the safety protection system. In addition, a number of mechanical and electrical improvements were made which support maintainability. The result is a DPPS

Maintenance, reliability and policies for orbital space station life support systems

International Nuclear Information System (INIS)

Russell, James F.; Klaus, David M.

2007-01-01

The performance of productive work on space missions is critical to sustaining a human presence on orbital space stations (OSS), the Moon, or Mars. Available time for productive work has potentially been impacted on past OSS missions by underestimating the crew time needed to maintain systems, such as the Environmental Control and Life Support System (ECLSS). To determine the cause of this apparent disconnect between the design and operation of an OSS, documented crew time for maintenance was collected from the three Skylab missions and Increments 4-8 on the International Space Station (ISS), and the data was contrasted to terrestrial facility maintenance norms. The results of the ISS analysis showed that for four operational and seven functional categories, the largest deviation of 60.4% over the design time was caused by three of the four operational categories not being quantitatively included in the design documents. In a cross category analysis, 35.3% of the crew time was found to have been used to repair air and waste handling systems. The air system required additional crew time for maintenance due to a greater than expected failure rate and resultant increased time needed for repairs. Therefore, it appears that the disconnect between the design time and actual operations for ECLSS maintenance on ISS was caused by excluding non-repair activities from the estimates and experiencing greater than expected technology maintenance requirements. Based on these ISS and Skylab analyses, future OSS designs (and possibly lunar and Martian missions as well) should consider 3.0-3.3 h/day for crews of 2 to 3 as a baseline of crew time needed for ECLSS maintenance

RTE - Reliability report 2016

International Nuclear Information System (INIS)

2017-06-01

Every year, RTE produces a reliability report for the past year. This document lays out the main factors that affected the electrical power system's operational reliability in 2016 and the initiatives currently under way intended to ensure its reliability in the future. Within a context of the energy transition, changes to the European interconnected network mean that RTE has to adapt on an on-going basis. These changes include the increase in the share of renewables injecting an intermittent power supply into networks, resulting in a need for flexibility, and a diversification in the numbers of stakeholders operating in the energy sector and changes in the ways in which they behave. These changes are dramatically changing the structure of the power system of tomorrow and the way in which it will operate - particularly the way in which voltage and frequency are controlled, as well as the distribution of flows, the power system's stability, the level of reserves needed to ensure supply-demand balance, network studies, assets' operating and control rules, the tools used and the expertise of operators. The results obtained in 2016 are evidence of a globally satisfactory level of reliability for RTE's operations in somewhat demanding circumstances: more complex supply-demand balance management, cross-border schedules at interconnections indicating operation that is closer to its limits and - most noteworthy - having to manage a cold spell just as several nuclear power plants had been shut down. In a drive to keep pace with the changes expected to occur in these circumstances, RTE implemented numerous initiatives to ensure high levels of reliability: - maintaining investment levels of euro 1.5 billion per year; - increasing cross-zonal capacity at borders with our neighbouring countries, thus bolstering the security of our electricity supply; - implementing new mechanisms (demand response, capacity mechanism, interruptibility, etc.); - involvement in tests or projects

Reliability analysis for the facility data acquisition interface system upgrade at TA-55

International Nuclear Information System (INIS)

Turner, W.J.; Pope, N.G.; Brown, R.E.

1995-05-01

Because replacement parts for the existing facility data acquisition interface system at TA-55 have become scarce and are no longer being manufactured, reliability studies were conducted to assess various possible replacement systems. A new control system, based on Allen-Bradley Programmable Logic Controllers (PLCs), was found to have a likely reliability 10 times that of the present system, if the existing Continuous Air Monitors (CAMS) were used. Replacement of the old CAMs with new CAMs will result in even greater reliability as these are gradually phased in. The new PLC-based system would provide for hot standby processors, redundant communications paths, and redundant power supplies, and would be expandable and easily maintained, as well as much more reliable. TA-55 is the Plutonium Processing Facility which processes and recovers Pu-239 from scrap materials

Standards in reliability and safety engineering

International Nuclear Information System (INIS)

O'Connor, Patrick

1998-01-01

This article explains how the highest 'world class' levels of reliability and safety are achieved, by adherence to the basic principles of excellence in design, production, support and maintenance, by continuous improvement, and by understanding that excellence and improvement lead to reduced costs. These principles are contrasted with the methods that have been developed and standardised, particularly military standards for reliability, ISO9000, and safety case regulations. The article concludes that the formal, standardised approaches are misleading and counterproductive, and recommends that they be replaced by a philosophy based on the realities of human performance

Mechanical properties of different types of space maintainers

Science.gov (United States)

Beldiman, M.-A.; Mârţu, I.; Leiţoiu, B.; Luchian, I.; Lupescu, O.; Bârcă, E. S.

2015-11-01

Currently, inside the oral cavity, the dental space maintainers are subjected to forces exerted on them when performing various functions; therefore, it is important to know how each of these mechanisms behave and respond to forces that are applied directly to them. The mechanical properties of the materials used in dentistry are defined by a set of characteristics representing the behaviour of their particular working conditions and it is qualitatively expressed by a number of parameters.The study aimed to determine the pressing force that can be taken by four 4 types of space maintainers frequently used in practice - fixed and removable, applied on four samples realized with human teeth extracted for orthodontic purposes. Static tests were carried out on a machine type short WDW-5 EC with a maximum force of 5 kN and a loading speed of 5 mm/min by a special testing machine, with an innovative appliance; data recording was automatically performed, using a computer with a special program that present the specific diagrams. Experimental determinations included the following aspects: to determine the maximum force that can be supported by each sample, and to observe the deformations. The values obtained indicate that the best option in terms of behavior under the conditions specified is the removable appliance, and the less functional version is the fixed space maintainer using brackets. According to tests conducted, the fracture strength was found to be more important for fixed space maintainers (band and loop, for example) so, in practice is using more frequent these types of space maintainers.

Awakening: a qualitative study on maintaining weight loss after bariatric surgery.

Science.gov (United States)

Liebl, Lori; Barnason, Susan; Brage Hudson, Diane

2016-04-01

To describe the experiences of adults who were successful in maintaining weight loss after bariatric surgery. The majority of studies examine a homogenous demographic group of postbariatric surgical patients who have gone through initial weight loss, which occurs within the first 12-24 months post surgery. Maintenance of weight loss begins 24 months after bariatric surgery; however, there is a paucity of research examining experiences during this period. The lack of conclusive research related to interactions between intrapersonal, behavioural and environmental influences suggests a need to develop a better understanding of patients' experiences related to weight loss maintenance post bariatric surgery. Bandura's Social Cognitive Theory provided the framework for the semi-structured interviews for this qualitative descriptive study. In-person interviews with n = 14 participants who were able to maintain weight loss at least 24 months after a bariatric surgery. Participants experienced an awakening and gained a new perspective on their life. They identified negative attitudes, influences and behaviours and modified their environment to support their desired healthy behaviour. To maintain weight loss, an individual must seek out and be surrounded by positive family and peer support influences. Positive support may provide the opportunity for an individual to place personal health needs as a priority. Therapeutic education and counselling for individuals, couples and families should occur during all phases of bariatric surgery. Communication techniques may empower clients to deflect negative comments and influences in a constructive manner. Support groups should accommodate the various phases of bariatric surgery. Clients should be prepared for how to work through emotions associated with weight fluctuations. © 2016 John Wiley & Sons Ltd.

Engineering high reliability, low-jitter Marx generators

International Nuclear Information System (INIS)

Schneider, L.X.; Lockwood, G.J.

1985-01-01

Multimodule pulsed power accelerators typically require high module reliability and nanosecond regime simultaneity between modules. Energy storage using bipolar Marx generators can meet these requirements. Experience gained from computer simulations and the development of the DEMON II Marx generator has led to a fundamental understanding of the operation of these multistage devices. As a result of this research, significant improvements in erection time jitter and reliability have been realized in multistage, bipolar Marx generators. Erection time jitter has been measured as low as 2.5 nanoseconds for the 3.2MV, 16-stage PBFA I Marx and 3.5 nanoseconds for the 6.0MV, 30-stage PBFA II (DEMON II) Marx, while maintaining exceptionally low prefire rates. Performance data are presented from the DEMON II Marx research program, as well as discussions on the use of computer simulations in designing low-jitter Marx generators

Implementation of a personnel reliability program as a facilitator of biosafety and biosecurity culture in BSL-3 and BSL-4 laboratories.

Science.gov (United States)

Higgins, Jacki J; Weaver, Patrick; Fitch, J Patrick; Johnson, Barbara; Pearl, R Marene

2013-06-01

In late 2010, the National Biodefense Analysis and Countermeasures Center (NBACC) implemented a Personnel Reliability Program (PRP) with the goal of enabling active participation by its staff to drive and improve the biosafety and biosecurity culture at the organization. A philosophical keystone for accomplishment of NBACC's scientific mission is simultaneous excellence in operations and outreach. Its personnel reliability program builds on this approach to: (1) enable and support a culture of responsibility based on human performance principles, (2) maintain compliance with regulations, and (3) address the risk associated with the insider threat. Recently, the Code of Federal Regulations (CFR) governing use and possession of biological select agents and toxins (BSAT) was amended to require a pre-access suitability assessment and ongoing evaluation for staff accessing Tier 1 BSAT. These 2 new requirements are in addition to the already required Federal Bureau of Investigation (FBI) Security Risk Assessment (SRA). Two years prior to the release of these guidelines, NBACC developed its PRP to supplement the SRA requirement as a means to empower personnel and foster an operational environment where any and all work with BSAT is conducted in a safe, secure, and reliable manner.

Reliability-Based Design and Planning of Inspection and Monitoring of Offshore Wind Turbines

DEFF Research Database (Denmark)

Marquez-Dominguez, Sergio

Maintaining and developing a sustainable wind industry is the main motivation of this PhD thesis entitled “Reliability-based design and planning of inspection and monitoring of offshore wind turbines”. In this thesis, statistical methods and probability theory are important mathematical tools used...... and offshore wind turbine foundations with the aim of improving the design, decreasing structural costs and increasing benefits. Recently, wind energy technology has started to adopt risk and reliability based inspection planning (RBI) as a methodology based on Bayesian decision theories together...

How reliable are case formulations? A systematic literature review.

Science.gov (United States)

Flinn, Lucinda; Braham, Louise; das Nair, Roshan

2015-09-01

This systematic literature review investigated the inter-rater and test-retest reliability of case formulations. We considered the reliability of case formulations across a range of theoretical modalities and the general quality of the primary research studies. A systematic search of five electronic databases was conducted in addition to reference list trawling to find studies that assessed the reliability of case formulation. This yielded 18 studies for review. A methodological quality assessment tool was developed to assess the quality of studies, which informed interpretation of the findings. Results indicated inter-rater reliability mainly ranging from slight (.1-.4) to substantial (.81-1.0). Some studies highlighted that training and increased experience led to higher levels of agreement. In general, psychodynamic formulations appeared to generate somewhat increased levels of reliability than cognitive or behavioural formulations; however, these studies also included methods that may have served to inflate reliability, for example, pooling the scores of judges. Only one study investigated the test-retest reliability of case formulations yielding support for the stability of formulations over a 3-month period. Reliability of case formulations is varied across a range of theoretical modalities, but can be improved; however, further research is required to strengthen our conclusions. Clinical implications: The findings from the review evidence some support for case formulation being congruent with the scientist-practitioner approach. The reliability of case formulation is likely to be improved through training and clinical experience. Limitations: The broad inclusion criteria may have introduced heterogeneity into the sample, which may have affected the results. Studies reviewed were limited to peer-reviewed journal articles written in the English language, which may represent a source of publication and selection bias. © 2014 The British Psychological Society.

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)

Axiomatic Design of Space Life Support Systems

Science.gov (United States)

Jones, Harry W.

2017-01-01

Systems engineering is an organized way to design and develop systems, but the initial system design concepts are usually seen as the products of unexplained but highly creative intuition. Axiomatic design is a mathematical approach to produce and compare system architectures. The two axioms are:- Maintain the independence of the functional requirements.- Minimize the information content (or complexity) of the design. The first axiom generates good system design structures and the second axiom ranks them. The closed system human life support architecture now implemented in the International Space Station has been essentially unchanged for fifty years. In contrast, brief missions such as Apollo and Shuttle have used open loop life support. As mission length increases, greater system closure and increased recycling become more cost-effective.Closure can be gradually increased, first recycling humidity condensate, then hygiene wastewater, urine, carbon dioxide, and water recovery brine. A long term space station or planetary base could implement nearly full closure, including food production. Dynamic systems theory supports the axioms by showing that fewer requirements, fewer subsystems, and fewer interconnections all increase system stability. If systems are too complex and interconnected, reliability is reduced and operations and maintenance become more difficult. Using axiomatic design shows how the mission duration and other requirements determine the best life support system design including the degree of closure.

Dynamic k-out-of-n system reliability with component partnership

International Nuclear Information System (INIS)

Coit, David W.; Chatwattanasiri, Nida; Wattanapongsakorn, Naruemon; Konak, Abdullah

2015-01-01

This paper describes a new k-out-of-n system reliability model that is appropriate for certain design problems when the minimum number of required components, k, changes dynamically in response to failures to maximize the utility of the available collection of functioning components. This new model shares some distinct similarities with weighted k-out-of-n models and for some problems they produce the same result. However, there are subtle and distinct differences, and in practice, there are some complex applications have not been properly explained or modeled by traditional or extended k-out-of-n system models. For this application, components are arranged in a k-out-of-n configuration of heterogeneous components with different performance levels. Component performance is indicated by a component-specific component partnership level; the fewer partners required to operate successfully implies higher performance. The components can work collectively with partners at the same level to maintain system reliability, or they can create a partnership group with components at higher performance levels which serve as replacements to provide the necessary number of working components. When components fail, the dynamic k-out-of-n configuration maintains reliability of the system with changing k by having components create partnerships with other components at the same level or above. To demonstrate the model, a system replacement maintenance policy based on a replacement interval variable is applied to an example system to obtain the optimal replacement time. - Highlights: • A new k-out-of-n system reliability model is presented. • Components can form partnerships with other components. • The new k-out-of-n model is presented with a dynamic or changing k. • The new model is for systems with components that must work together in a group

Nutritional support to maintain proper immune status during intense training.

Science.gov (United States)

Gleeson, Michael

2013-01-01

Prolonged exercise and heavy training are associated with depressed immune function which can increase the risk of picking up minor infections. To maintain robust immunity, athletes should eat a well-balanced diet sufficient to meet their energy, carbohydrate, protein, and micronutrient requirements. Dietary deficiencies of protein and specific micronutrients have long been associated with immune dysfunction and an adequate intake of iron, zinc, and vitamins A, D, E, B6 and B12 is particularly important in the maintenance of immune function. Consuming carbohydrate during prolonged strenuous exercise attenuates rises in stress hormones and appears to limit the degree of exercise-induced immune depression. Similar effects can be seen with daily ingestion of high-dose antioxidant vitamin supplements, though concerns have been expressed that excessive antioxidant intake may impair exercise training adaptations. It is safe to say with reasonable confidence that individual amino acids, colostrum, Echinacea, and zinc are unlikely to boost immunity or reduce infection risk in athletes. The ingestion of carbohydrate during exercise and daily consumption of probiotic and plant polyphenol (e.g. quercetin)-containing supplements or foodstuffs (e.g. non-alcoholic beer) currently offer the best chance of success. This approach is likely to be most effective for individuals who are particularly prone to illness. Copyright © 2013 Nestec Ltd., Vevey/S. Karger AG, Basel.

Maintaining US Space Weather Capabilities after DMSP: Research to Operations

Science.gov (United States)

Machuzak, J. S.; Gentile, L. C.; Burke, W. J.; Holeman, E. G.; Ober, D. M.; Wilson, G. R.

2012-12-01

The first Defense Meteorological Satellite Program (DMSP) spacecraft was launched in 1972; the last is scheduled to fly in 2020. Presently, there is no replacement for the space-weather monitoring sensors that now fly on DMSP. The present suite has provided comprehensive, long-term records that constitute a critical component of the US space weather corporate memory. Evolving operational needs and research accomplishments justify continued collection of space environmental data. Examples include measurements to: (1) Monitor the Dst index in real time as a driver of next-generation satellite drag models; (2) Quantify electromagnetic energy fluxes from deep space to the ionosphere/ thermosphere that heat neutrals, drive disturbance-dynamo winds and degrade precise orbit determinations; (3) Determine strengths of stormtime electric fields at high and low latitudes that lead to severe blackouts and spacecraft anomalies; (4) Specify variability of plasma density irregularities, equatorial plasma bubbles, and the Appleton anomaly to improve reliability of communication, navigation and surveillance links; (5) Characterize energetic particle fluxes responsible for auroral clutter and radar degradation; (6) Map regions of L-Band scintillation for robust GPS applications; and (7) Update the World Magnetic Field Model needed to maintain guidance system superiority. These examples illustrate the utility of continued space environment awareness. Comprehensive assessments of both operational requirements and research advances are needed to make informed selections of sensors and spacecraft that support future capabilities. A proposed sensor set and satellite constellation to provide the needed measurement capabilities will be presented.

Reasoning with Inductive Argument Test: A Study of Validity and Reliability

Directory of Open Access Journals (Sweden)

Mehmet Emrah Karadere

2013-12-01

Conclusion: The preliminary data obtained from the study of reliability and validity of the scale shows that ‘Reasoning with Inductive Argument Test’ supports reliability and validity in Turkish population. [JCBPR 2013; 2(3.000: 156-161

Test-retest reliability of the Military Pre-training Questionnaire.

Science.gov (United States)

Robinson, M; Stokes, K; Bilzon, J; Standage, M; Brown, P; Thompson, D

2010-09-01

Musculoskeletal injuries are a significant cause of morbidity during military training. A brief, inexpensive and user-friendly tool that demonstrates reliability and validity is warranted to effectively monitor the relationship between multiple predictor variables and injury incidence in military populations. To examine the test-retest reliability of the Military Pre-training Questionnaire (MPQ), designed specifically to assess risk factors for injury among military trainees across five domains (physical activity, injury history, diet, alcohol and smoking). Analyses were based on a convenience sample of 58 male British Army trainees. Kappa (kappa), weighted kappa (kappa(w)) and intraclass correlation coefficients (ICC) were used to evaluate the 2-week test-retest reliability of the MPQ. For index measures constituting the assessment of a given construct, internal consistency was assessed by Cronbach's alpha (alpha) coefficients. Reliability of individual items ranged from poor to almost perfect (kappa range = 0.45-0.86; kappa(w) range = 0.11-0.91; ICC range = 0.34-0.86) with most items demonstrating moderate reliability. Overall scores related to physical activity, diet, alcohol and smoking constructs were reliable between both administrations (ICC = 0.63-0.85). Support for the internal consistency of the incorporated alcohol (alpha = 0.78) and cigarette (alpha = 0.75) scales was also provided. The MPQ is a reliable self-report instrument for assessing multiple injury-related risk factors during initial military training. Further assessment of the psychometric properties of the MPQ (e.g. different types of validity) with military populations/samples will support its interpretation and use in future surveillance and epidemiological studies.

AECL's support to operating plants world wide

International Nuclear Information System (INIS)

Azeez, S.; Kakaria, B.K.; Hinchley, E.M.

1998-01-01

Through their operating records, CANDU reactors have established themselves as a successful and cost-effective source of electricity in Canada and abroad. They have proven to be safe, reliable and economical. A variety of factors have contributed to the enviable CANDU record, such as a sound design based on proven principles supported by effective development programs, along with dedicated plant owners committed to excellence in safely maintaining and operating their plants. Atomic Energy of Canada Limited (AECL), the CANDU designer, has continuously maintained a close relationship with owners/operators of the plants in Canada, Argentina, Romania and South Korea. AECL and the plant operators have all benefited from this strengthening relationship by sharing experience and information. CANDU plant operators have been required to respond decisively to the economic realities of downward cost pressures and deregulation. Operating, Maintenance and Administration (OM and A) costs are being given a new focus as plant owners review each cost element to improve the economic returns from their investments. Amongst the three main OM and A constituents, plant maintenance costs are the most variable and have the largest influence on effective plant operations. The correlation between effective plant maintenance and high capacity factors shows clearly the importance of proactive maintenance planning to reduce the frequency and duration of forced plant outages and their negative impacts on plant economics. This paper describes the management processes and organizational structures m AECL that support plant operations and maintenance in operating CANDU plants with cost effective products and services. (author)

Starship Life Support

Science.gov (United States)

Jones, Harry W.

2009-01-01

The design and mass cost of a starship and its life support system are investigated. The mission plan for a multi generational interstellar voyage to colonize a new planet is used to describe the starship design, including the crew habitat, accommodations, and life support. Only current technology is assumed. Highly reliable life support systems can be provided with reasonably small additional mass, suggesting that they can support long duration missions. Bioregenerative life support, growing crop plants that provide food, water, and oxygen, has been thought to need less mass than providing stored food for long duration missions. The large initial mass of hydroponics systems is paid for over time by saving the mass of stored food. However, the yearly logistics mass required to support a bioregenerative system exceeds the mass of food solids it produces, so that supplying stored dehydrated food always requires less mass than bioregenerative food production. A mixed system that grows about half the food and supplies the other half dehydrated has advantages that allow it to breakeven with stored dehydrated food in about 66 years. However, moderate increases in the hydroponics system mass to achieve high reliability, such as adding spares that double the system mass and replacing the initial system every 100 years, increase the mass cost of bioregenerative life support. In this case, the high reliability half food growing, half food supplying system does not breakeven for 389 years. An even higher reliability half and half system, with three times original system mass and replacing the system every 50 years, never breaks even. Growing food for starship life support requires more mass than providing dehydrated food, even for multigeneration voyages of hundreds of years. The benefits of growing some food may justify the added mass cost. Much more efficient recycling food production is wanted but may not be possible. A single multigenerational interstellar voyage to

Reliability-based inspection of prestressed concrete containment structures

International Nuclear Information System (INIS)

Pandey, M.D.

1996-03-01

A study was undertaken to develop a reliability-based approach to the planning of inspection programs for prestressed concrete containment structures. The main function of the prestressing system is to ensure the leak integrity of the containment by maintaining a compressive state of stress under the tensile forces which arise in a hypothesized loss of coolant accident. Prestressing force losses (due to creep and shrinkage, stress relaxation or tendon corrosion) can lead to tensile stresses under accident pressure, resulting in loss of containment leak integrity due to concrete cracking and tensile yielding of the non-prestressed reinforcement. Therefore, the evaluation of prestressing inspection programs was based on their effectiveness in maintaining an acceptable reliability level with respect to a limit state representing yeilding of non-prestressed reinforcement. An annual target reliability of 10 -4 was used for this limit state. As specified in CSA-N287.7, the evaluation of prestressing systems for containment structures is based on the results of lift-off tests to determine the prestressing force. For unbonded systems the tests are carried out on a randomly selected sample from each tendon group in the structure. For bonded systems, the test is carried out on an unbonded test beam that matches the section geometry and material properties of the containment structure. It was found that flexural testing is useful in updating the probability of concrete cracking under accident pressure. For unbonded systems, the analysis indicated that the sample size recommended by the CSA Standard (4% of the tendon population) is adequate. The CSA recommendation for a five year inspection interval is conservative unless severe degradation of the prestressing system, characterized by a high prestressing loss rate (>3%) and a large coefficient of variation of the measured prestressing force (>15%), is observed

Global Nuclear Fuel launches GNF{sub 3} and NSF: The most reliable BWR fuel just got better

Energy Technology Data Exchange (ETDEWEB)

Cantonwine, P.; Schneider, R.; Hunt, B.

2015-11-01

Bases on evolutionary design changes and advanced technology developed by Global Nuclear Fuel (GNF), the GNF3 fuel assembly is designed to offer customers with improved fuel economics, increased performance and flexibility in operation while maintaining the superior reliability of GNF2, the most reliable design in GNFs history. In addition to improved fuel utilization and performance, GNF3 is designed and manufactured to be more resistant to debris capture, to eliminate channel control blade interference concerns, and to exhibit to best available corrosion resistance of any boiling water reactor fuel. While delivering fuel cycle savings and reliability benefits with GNF3, GNF maintains a similar licensing and operating basis to GNF2, thereby minimizing fuel transition risks. GNF3 is available in lead use assembly quantities to customers today. Eight GNF3 lead use assemblies are in operation at two utilities in the USA GNF3 is scheduled to be available for full reloads in 2018. (Author)

Reliability and validity of the Polish version of the Movement Imagery Questionnaire-3 (MIQ-3

Directory of Open Access Journals (Sweden)

Dagmara Budnik-Przybylska

2016-10-01

Full Text Available Background Imagery is often beneficial not only in gaining a psychological advantage when competing but also in building self-esteem and self-confidence. The aim of this study was to examine the reliability and validity of the Polish adaptation of the Movement Imagery Questionnaire-3 (MIQ-3, consisting of 12 questions measuring 3 dimensions: visual internal imagery, visual external imagery and kinesthetic imagery. Participants and procedure A sample of athletes (N = 276 – 102 women, 174 men (M = 21.25, SD = 6.35 of various disciplines (football, volleyball, karate, swimming, etc. with different sport experience (from recreation to the national team filled in the MIQ-3 questionnaire in the Polish language. Results The results of the confirmatory factor analysis (CFA with maximum likelihood confirmed that the established three-factor model reflects well the relationships observed in the respondents’ answers (satisfactory value of RMSEA below the recommended value of .05 (RMSEA = .04 and a high value of the index above .90 CFI (CFI = .93. Reliability indicators (composite reliability – CR observed for individual factors indicated a very high internal consistency (external visual imagery = .75, internal visual imagery = .79 and kinesthetic imagery = .82. The results indicated that good stability and internal consistency were maintained over a 3-week period. In addition, analyses were examined across age, level of experience and gender. Conclusions The results of the present study support the psychometric properties of the Polish adaptation of the MIQ-3.

Comprehensive low-cost reliability centered maintenance. Final report

International Nuclear Information System (INIS)

Rotton, S.J.; Dozier, I.J.; Thow, R.

1995-09-01

Reliability Centered Maintenance (RCM) is a maintenance optimization approach that all electric utilities can apply to power plant systems. The Electric Power Research Institute and PECO Energy Company jointly sponsored this Comprehensive Low-Cost Reliability Centered Maintenance project to demonstrate that the standard RCM methodology could be streamlined to reduce the cost of analysis while maintaining a high quality product. EPRI's previous investigation of streamlined RCM methods being pioneered in the nuclear industry indicated that PECO Energy could expect to optimize its maintenance program at reduced cost by carefully controlling the scope without sacrificing documentation or technical quality. Using the insights obtained from these previous studies, three methods were defined in this project and were demonstrated in a large scale application to 60 systems at both the Limerick Generating Station and the Peach Bottom Atomic Power Station

Integrated logistic support concept in the design of nuclear power plants

International Nuclear Information System (INIS)

Martin-Onraet, M.; Degrave, C.; Meuwisse, C.

1996-01-01

Considering its plant operating experience, the analysis of foreign practice and the development of new design approaches and tools, Electricite de France (EDF) is convinced that it is possible to improve new plant design, operation and maintenance without increasing too much investment costs. To remain competitive it is necessary to maintain the kWh production cost of the future unit at a level close to those of the latest unit under construction (N4 series), while raising the Safety level. To minimize the kWh cost EDF has decided to implement the CIDEM project (French acronym for Design Integrating Availability, Operating Experience and Maintenance), an analytic and systematic process for studying new projects, aiming at a design optimization including investment, maintenance, availability and radiation exposure objectives. This approach aims at a single goal: to minimize the kWh production cost incorporating investment operation and fuel cost, based on experience from French and foreign units. This process, already widely practiced in other industries or services (aerospace, defense, ...), uses concepts known by the acronyms RAM (Reliability, Availability, Maintainability) RCM (Reliability, Centered Maintenance) and ILS (Integrated Logistic Support). The first CIDEM application is centered on the future French nuclear unit construction program, known as the REP 2000 program but the approach could be applied to other Reactor type or fossil-fired units in particular for its methodological aspect. The purpose of this paper is to introduce the EDF ILS concept

The Experience of Young Women Living in a Prostitution Area in Maintaining Their Reproductive Health.

Science.gov (United States)

Dovis, Vonyca; Setyowati; Kurniawati, Wiwit

Young women face a difficult situation when they live in a prostitution area or red light district. A phenomenological approach was applied to explore the experiences in maintaining reproductive health of 10 young women living in the prostitution area in Lampung, one of the provinces in Sumatra. Thematic content analysis found 7 themes including: (1) The participants' perception of prostitution as a place of naughty women and free sexual activity that can transmit STDs and influence adolescent psychology; (2) The ways the participants kept their reproductive organs healthy were through maintaining friendships, maintaining personal hygiene, avoiding free sexual activity, eating healthy food, and having routine medical checkups; (3) Information support was gained from family, health workers, media, and teachers; (4) Emotional support from family and friends; (5) Barriers to maintaining good health were inaccessible health facilities and an underfunded health service; (6) The needs of the participants were reproductive health services and clean environment; (7) The participants hoped for health education and intensive health services with friendly nurses. The results of this research illustrate that there is a need for socializing intensive ways to maintain reproductive health, especially in a risky environment.

Systems reliability/structural reliability

International Nuclear Information System (INIS)

Green, A.E.

1980-01-01

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

Reliability of an x-ray system for calibrating and testing personal radiation dosimeters

Science.gov (United States)

Guimarães, M. C.; Silva, C. R. E.; Rosado, P. H. G.; Cunha, P. G.; Da Silva, T. A.

2018-03-01

Metrology laboratories are expected to maintain standardized radiation beams and traceable standard dosimeters to provide reliable calibrations or testing of detectors. Results of the characterization of an x-ray system for performing calibration and testing of radiation dosimeters used for individual monitoring are shown in this work.

User's guide to the Reliability Estimation System Testbed (REST)

Science.gov (United States)

Nicol, David M.; Palumbo, Daniel L.; Rifkin, Adam

1992-01-01

The Reliability Estimation System Testbed is an X-window based reliability modeling tool that was created to explore the use of the Reliability Modeling Language (RML). RML was defined to support several reliability analysis techniques including modularization, graphical representation, Failure Mode Effects Simulation (FMES), and parallel processing. These techniques are most useful in modeling large systems. Using modularization, an analyst can create reliability models for individual system components. The modules can be tested separately and then combined to compute the total system reliability. Because a one-to-one relationship can be established between system components and the reliability modules, a graphical user interface may be used to describe the system model. RML was designed to permit message passing between modules. This feature enables reliability modeling based on a run time simulation of the system wide effects of a component's failure modes. The use of failure modes effects simulation enhances the analyst's ability to correctly express system behavior when using the modularization approach to reliability modeling. To alleviate the computation bottleneck often found in large reliability models, REST was designed to take advantage of parallel processing on hypercube processors.

Plant lifetime reliability and risk: Addressing today's strategies for making tomorrow's decisions

International Nuclear Information System (INIS)

Boccio, J.L.

1986-01-01

This paper presents an overview of some of the research projects, conducted for the US Nuclear Regulatory Commission (NRC) that deal with the question: How can an acceptable level of risk of a nuclear power plant be maintained throughout its design life? With a viewpoint that life extension planning for a plant can be viewed as a long-range, strategic maintenance program, the products of this research are discussed from the perspective of being elements that can tie day-to-day, plant operational tactical decisions on component/system reliability with long-range strategic maintenance goals. A common factor in addressing issues associated with design life and life extension is the issue of component aging and the reliability implications of aging. A time-dependent reliability model is described which contains some of the requisite ingredients and is built on a framework from which the component aging/component reliability issue can be addressed. By way of select examples, the additional work needed to further address plant lifetime reliability and risk is indicated

Are YouTube videos accurate and reliable on basic life support and cardiopulmonary resuscitation?

Science.gov (United States)

Yaylaci, Serpil; Serinken, Mustafa; Eken, Cenker; Karcioglu, Ozgur; Yilmaz, Atakan; Elicabuk, Hayri; Dal, Onur

2014-10-01

The objective of this study is to investigate reliability and accuracy of the information on YouTube videos related to CPR and BLS in accord with 2010 CPR guidelines. YouTube was queried using four search terms 'CPR', 'cardiopulmonary resuscitation', 'BLS' and 'basic life support' between 2011 and 2013. Sources that uploaded the videos, the record time, the number of viewers in the study period, inclusion of human or manikins were recorded. The videos were rated if they displayed the correct order of resuscitative efforts in full accord with 2010 CPR guidelines or not. Two hundred and nine videos meeting the inclusion criteria after the search in YouTube with four search terms ('CPR', 'cardiopulmonary resuscitation', 'BLS' and 'basic life support') comprised the study sample subjected to the analysis. Median score of the videos is 5 (IQR: 3.5-6). Only 11.5% (n = 24) of the videos were found to be compatible with 2010 CPR guidelines with regard to sequence of interventions. Videos uploaded by 'Guideline bodies' had significantly higher rates of download when compared with the videos uploaded by other sources. Sources of the videos and date of upload (year) were not shown to have any significant effect on the scores received (P = 0.615 and 0.513, respectively). The videos' number of downloads did not differ according to the videos compatible with the guidelines (P = 0.832). The videos downloaded more than 10,000 times had a higher score than the others (P = 0.001). The majority of You-Tube video clips purporting to be about CPR are not relevant educational material. Of those that are focused on teaching CPR, only a small minority optimally meet the 2010 Resucitation Guidelines. © 2014 Australasian College for Emergency Medicine and Australasian Society for Emergency Medicine.

Test rig overview for validation and reliability testing of shutdown system software

International Nuclear Information System (INIS)

Zhao, M.; McDonald, A.; Dick, P.

2007-01-01

The test rig for Validation and Reliability Testing of shutdown system software has been upgraded from the AECL Windows-based test rig previously used for CANDU6 stations. It includes a Virtual Trip Computer, which is a software simulation of the functional specification of the trip computer, and a real-time trip computer simulator in a separate chassis, which is used during the preparation of trip computer test cases before the actual trip computers are available. This allows preparation work for Validation and Reliability Testing to be performed in advance of delivery of actual trip computers to maintain a project schedule. (author)

Constructing the Best Reliability Data for the Job

Science.gov (United States)

Kleinhammer, R. K.; Kahn, J. C.

2014-01-01

Modern business and technical decisions are based on the results of analyses. When considering assessments using "reliability data", the concern is how long a system will continue to operate as designed. Generally, the results are only as good as the data used. Ideally, a large set of pass/fail tests or observations to estimate the probability of failure of the item under test would produce the best data. However, this is a costly endeavor if used for every analysis and design. Developing specific data is costly and time consuming. Instead, analysts rely on available data to assess reliability. Finding data relevant to the specific use and environment for any project is difficult, if not impossible. Instead, we attempt to develop the "best" or composite analog data to support our assessments. One method used incorporates processes for reviewing existing data sources and identifying the available information based on similar equipment, then using that generic data to derive an analog composite. Dissimilarities in equipment descriptions, environment of intended use, quality and even failure modes impact the "best" data incorporated in an analog composite. Once developed, this composite analog data provides a "better" representation of the reliability of the equipment or component can be used to support early risk or reliability trade studies, or analytical models to establish the predicted reliability data points. Data that is more representative of reality and more project specific would provide more accurate analysis, and hopefully a better final decision.

Constructing the "Best" Reliability Data for the Job

Science.gov (United States)

DeMott, D. L.; Kleinhammer, R. K.

2014-01-01

Modern business and technical decisions are based on the results of analyses. When considering assessments using "reliability data", the concern is how long a system will continue to operate as designed. Generally, the results are only as good as the data used. Ideally, a large set of pass/fail tests or observations to estimate the probability of failure of the item under test would produce the best data. However, this is a costly endeavor if used for every analysis and design. Developing specific data is costly and time consuming. Instead, analysts rely on available data to assess reliability. Finding data relevant to the specific use and environment for any project is difficult, if not impossible. Instead, we attempt to develop the "best" or composite analog data to support our assessments. One method used incorporates processes for reviewing existing data sources and identifying the available information based on similar equipment, then using that generic data to derive an analog composite. Dissimilarities in equipment descriptions, environment of intended use, quality and even failure modes impact the "best" data incorporated in an analog composite. Once developed, this composite analog data provides a "better" representation of the reliability of the equipment or component can be used to support early risk or reliability trade studies, or analytical models to establish the predicted reliability data points. Data that is more representative of reality and more project specific would provide more accurate analysis, and hopefully a better final decision.

Standard Hardware Acquisition and Reliability Program's (SHARP's) efforts in incorporating fiber optic interconnects into standard electronic module (SEM) connectors

Science.gov (United States)

Riggs, William R.

1994-05-01

SHARP is a Navy wide logistics technology development effort aimed at reducing the acquisition costs, support costs, and risks of military electronic weapon systems while increasing the performance capability, reliability, maintainability, and readiness of these systems. Lower life cycle costs for electronic hardware are achieved through technology transition, standardization, and reliability enhancement to improve system affordability and availability as well as enhancing fleet modernization. Advanced technology is transferred into the fleet through hardware specifications for weapon system building blocks of standard electronic modules, standard power systems, and standard electronic systems. The product lines are all defined with respect to their size, weight, I/O, environmental performance, and operational performance. This method of defining the standard is very conducive to inserting new technologies into systems using the standard hardware. This is the approach taken thus far in inserting photonic technologies into SHARP hardware. All of the efforts have been related to module packaging; i.e. interconnects, component packaging, and module developments. Fiber optic interconnects are discussed in this paper.

Reliable Communication in Wireless Meshed Networks using Network Coding

DEFF Research Database (Denmark)

Pahlevani, Peyman; Paramanathan, Achuthan; Hundebøll, Martin

2012-01-01

The advantages of network coding have been extensively studied in the field of wireless networks. Integrating network coding with existing IEEE 802.11 MAC layer is a challenging problem. The IEEE 802.11 MAC does not provide any reliability mechanisms for overheard packets. This paper addresses...... this problem and suggests different mechanisms to support reliability as part of the MAC protocol. Analytical expressions to this problem are given to qualify the performance of the modified network coding. These expressions are confirmed by numerical result. While the suggested reliability mechanisms...

System reliability as perceived by maintenance personnel on petroleum production facilities

International Nuclear Information System (INIS)

Antonovsky, A.; Pollock, C.; Straker, L.

2016-01-01

The aim of this research was to understand the relationship between maintenance staff perceptions of organisational effectiveness and operational reliability in petroleum operations. Engineering measures exist that assess the effectiveness of maintenance and reliability of equipment. These measures are typically retrospective and may not provide insight into what impedes system reliability. Perceptions of organisational effectiveness by the workforce may provide a predictive measure that could improve our understanding of the human factors that influence system reliability. Maintenance personnel (n=133) from nine petroleum production facilities completed a survey as part of a study of human factors and maintenance reliability. 69 respondents (51.9%) provided comments to an open-ended question in the survey, and these data were analysed using Interpretive Phenomenological Analysis to extract themes. Four super-ordinate themes were identified from the analysis: 1) Communication and access to information, 2) Efficiency of current work systems, 3) Need for better workgroup support, and 4) Management impacts on the workplace. We found a significant relationship between the frequency of the four super-ordinate themes and the facility reliability level as measured by ‘Mean Time Between Failures’: χ"2(6,N=158)=16.2, p=.013. These results demonstrated that operational effectiveness might be differentiated on the basis of survey-derived perceptions of maintenance personnel. - Highlights: • Thematic analysis of survey comments provided insights into workplace reliability • Worker’s comments on reliability related to technical data on time between failures • Management decision-making was the main theme in the lower reliability workplaces • Improving efficiency was the main theme in the higher reliability workplaces • Communication and better workgroup support were themes at all reliability levels

Developing Sustainable Life Support System Concepts

Science.gov (United States)

Thomas, Evan A.

2010-01-01

Sustainable spacecraft life support concepts may allow the development of more reliable technologies for long duration space missions. Currently, life support technologies at different levels of development are not well evaluated against each other, and evaluation methods do not account for long term reliability and sustainability of the hardware. This paper presents point-of-departure sustainability evaluation criteria for life support systems, that may allow more robust technology development, testing and comparison. An example sustainable water recovery system concept is presented.

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.

Bridging Human Reliability Analysis and Psychology, Part 2: A Cognitive Framework to Support HRA

Energy Technology Data Exchange (ETDEWEB)

April M. Whaley; Stacey M. L. Hendrickson; Ronald L. Boring; Jing Xing

2012-06-01

This is the second of two papers that discuss the literature review conducted as part of the U.S. Nuclear Regulatory Commission (NRC) effort to develop a hybrid human reliability analysis (HRA) method in response to Staff Requirements Memorandum (SRM) SRM-M061020. This review was conducted with the goal of strengthening the technical basis within psychology, cognitive science and human factors for the hybrid HRA method being proposed. An overview of the literature review approach and high-level structure is provided in the first paper, whereas this paper presents the results of the review. The psychological literature review encompassed research spanning the entirety of human cognition and performance, and consequently produced an extensive list of psychological processes, mechanisms, and factors that contribute to human performance. To make sense of this large amount of information, the results of the literature review were organized into a cognitive framework that identifies causes of failure of macrocognition in humans, and connects those proximate causes to psychological mechanisms and performance influencing factors (PIFs) that can lead to the failure. This cognitive framework can serve as a tool to inform HRA. Beyond this, however, the cognitive framework has the potential to also support addressing human performance issues identified in Human Factors applications.

Reliability of an x-ray system for calibrating and testing personal radiation dosimeters

Energy Technology Data Exchange (ETDEWEB)

Guimarães, M.C.; Silva, C.R.E.; Silva, T.A. da [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Rosado, P.H.G.; Cunha, P.G. [Instituto de Radioproteção e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

2017-07-01

Metrology laboratories are expected to maintain standardized radiation beams and traceable standard dosimeters to provide reliable calibrations or testing of detectors. Results of the characterization of an x-ray system for performing calibration and testing of radiation dosimeters used for individual monitoring are shown in this work. (author)

Reliability of an x-ray system for calibrating and testing personal radiation dosimeters

International Nuclear Information System (INIS)

Guimarães, M.C.; Silva, C.R.E.; Silva, T.A. da; Rosado, P.H.G.; Cunha, P.G.

2017-01-01

Metrology laboratories are expected to maintain standardized radiation beams and traceable standard dosimeters to provide reliable calibrations or testing of detectors. Results of the characterization of an x-ray system for performing calibration and testing of radiation dosimeters used for individual monitoring are shown in this work. (author)

Proceedings of the international workshop on reliability data collection in support of PSA, maintenance and life-assurance programmes

International Nuclear Information System (INIS)

1996-01-01

The utilisation of data to support Probabilistic Safety Assessments, Maintenance Activities and Life-Assurance Programmes is becoming more widely recognized as these areas become more and more developed throughout the nuclear industry. Almost every member country of the OECD Nuclear Energy Agency uses PSA in one way or another in their assessment of nuclear power plant safety. A majority of utilities and licensees have completed or are in the process of planning plant specific PSAs. Operability costs associated with maintenance activities and life assurance programmes are highly dependent upon the data and how it is utilized. Considering these statements and the various suggestions made, the Workshop addressed the following topics concerning reliability data collection: data compilation systems; data bases development and management; data application; parameter estimation; common cause failure and dependent failure data

Proceedings of the international workshop on reliability data collection in support of PSA, maintenance and life-assurance programmes

Energy Technology Data Exchange (ETDEWEB)

NONE

1996-07-01

The utilisation of data to support Probabilistic Safety Assessments, Maintenance Activities and Life-Assurance Programmes is becoming more widely recognized as these areas become more and more developed throughout the nuclear industry. Almost every member country of the OECD Nuclear Energy Agency uses PSA in one way or another in their assessment of nuclear power plant safety. A majority of utilities and licensees have completed or are in the process of planning plant specific PSAs. Operability costs associated with maintenance activities and life assurance programmes are highly dependent upon the data and how it is utilized. Considering these statements and the various suggestions made, the Workshop addressed the following topics concerning reliability data collection: data compilation systems; data bases development and management; data application; parameter estimation; common cause failure and dependent failure data

Original article The Imagination in Sport Questionnaire – reliability and validity characteristics

Directory of Open Access Journals (Sweden)

Dagmara Budnik-Przybylska

2014-07-01

Full Text Available Background Imagery is an effective performance enhancement technique. Imagery has been described previously in a range of psychological domains. Measuring imagery is critical in research and practice in sport. Self-report questionnaires are the most regularly used method. The aim of the present study was to examine reliability and validity characteristics of the Imagination in Sport Questionnaire (Kwestionariusz Wyobraźni w Sporcie – KWS. Participants and procedure Five and hundred eight (N = 326 – study I; N = 182 – study II Polish athletes completed questionnaires (169 male, 156 female – study I; 139 male, 43 female – study II, aged between 12 and 57 years (M = 22.08, SD = 8.18 – study I; age 19-24, M = 20.46, SD = 1.1 – study II, at different competitive levels and recruited from various sports disciplines. Results Results indicated the maintained good stability and internal consistency over a 3-week period. Results of confirmatory factor analysis suggested that the 7-factor structure of the KWS resulted in acceptable model fit indices (NC = 2416.63, df = 1203, GFI = 0.944, AGFI = 0.944, CFI = 0.786, RMSEA = 0.056, p (RMSEA < 0.05 = 0.002 – first study; NC = 2234.39, df = 1203, GFI = 0.673, AGFI = = 0.640, CFI = 0.691, RMSEA = 0.069, p (RMSEA < 0.05 = = 0.000 – second study. Concurrent validity was supported by examination of the relationships between the KWS subscales and the SIAM (Sport Imagery Ability Measure in Polish adaptation. In addition, differences in athletes’ imagery ability were examined across competitive levels, and in relation to both gender and age. Conclusions Overall, the results supported the reliability and construct validity of the KWS.

Characteristics and application study of AP1000 NPPs equipment reliability classification method

International Nuclear Information System (INIS)

Guan Gao

2013-01-01

AP1000 nuclear power plant applies an integrated approach to establish equipment reliability classification, which includes probabilistic risk assessment technique, maintenance rule administrative, power production reliability classification and functional equipment group bounding method, and eventually classify equipment reliability into 4 levels. This classification process and result are very different from classical RCM and streamlined RCM. It studied the characteristic of AP1000 equipment reliability classification approach, considered that equipment reliability classification should effectively support maintenance strategy development and work process control, recommended to use a combined RCM method to establish the future equipment reliability program of AP1000 nuclear power plants. (authors)

Human factors review of power plant maintainability. Final report

International Nuclear Information System (INIS)

Seminara, J.L.; Parsons, S.O.

1981-02-01

Human factors engineering is an interdisciplinary science and technology concerned with shaping the design of machines, facilities, and operational environments to promote safe, efficient, and reliable performance on the part of operators and maintainers of equipment systems. The human factors aspects of five nuclear power plants and four fossil fuel plants were evaluated using such methods as a check list guided observation system, structured interviews with maintenance personnel, direct observation of maintenance tasks, reviews of procedures, and analyses of maintenance errors or accidents by means of the critical incident technique. The study revealed a wide variety of human factors problem areas, most of which are extensively photodocumented. The study recommends that a more systematic and formal approach to ensure that future power plants are human engineered to the needs of maintenance personnel

Uncertainties and reliability theories for reactor safety

International Nuclear Information System (INIS)

Veneziano, D.

1975-01-01

What makes the safety problem of nuclear reactors particularly challenging is the demand for high levels of reliability and the limitation of statistical information. The latter is an unfortunate circumstance, which forces deductive theories of reliability to use models and parameter values with weak factual support. The uncertainty about probabilistic models and parameters which are inferred from limited statistical evidence can be quantified and incorporated rationally into inductive theories of reliability. In such theories, the starting point is the information actually available, as opposed to an estimated probabilistic model. But, while the necessity of introducing inductive uncertainty into reliability theories has been recognized by many authors, no satisfactory inductive theory is presently available. The paper presents: a classification of uncertainties and of reliability models for reactor safety; a general methodology to include these uncertainties into reliability analysis; a discussion about the relative advantages and the limitations of various reliability theories (specifically, of inductive and deductive, parametric and nonparametric, second-moment and full-distribution theories). For example, it is shown that second-moment theories, which were originally suggested to cope with the scarcity of data, and which have been proposed recently for the safety analysis of secondary containment vessels, are the least capable of incorporating statistical uncertainty. The focus is on reliability models for external threats (seismic accelerations and tornadoes). As an application example, the effect of statistical uncertainty on seismic risk is studied using parametric full-distribution models

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)

Reliability of Circumplex Axes

Directory of Open Access Journals (Sweden)

Micha Strack

2013-06-01

Full Text Available We present a confirmatory factor analysis (CFA procedure for computing the reliability of circumplex axes. The tau-equivalent CFA variance decomposition model estimates five variance components: general factor, axes, scale-specificity, block-specificity, and item-specificity. Only the axes variance component is used for reliability estimation. We apply the model to six circumplex types and 13 instruments assessing interpersonal and motivational constructs—Interpersonal Adjective List (IAL, Interpersonal Adjective Scales (revised; IAS-R, Inventory of Interpersonal Problems (IIP, Impact Messages Inventory (IMI, Circumplex Scales of Interpersonal Values (CSIV, Support Action Scale Circumplex (SAS-C, Interaction Problems With Animals (IPI-A, Team Role Circle (TRC, Competing Values Leadership Instrument (CV-LI, Love Styles, Organizational Culture Assessment Instrument (OCAI, Customer Orientation Circle (COC, and System for Multi-Level Observation of Groups (behavioral adjectives; SYMLOG—in 17 German-speaking samples (29 subsamples, grouped by self-report, other report, and metaperception assessments. The general factor accounted for a proportion ranging from 1% to 48% of the item variance, the axes component for 2% to 30%; and scale specificity for 1% to 28%, respectively. Reliability estimates varied considerably from .13 to .92. An application of the Nunnally and Bernstein formula proposed by Markey, Markey, and Tinsley overestimated axes reliabilities in cases of large-scale specificities but otherwise works effectively. Contemporary circumplex evaluations such as Tracey’s RANDALL are sensitive to the ratio of the axes and scale-specificity components. In contrast, the proposed model isolates both components.

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

International Nuclear Information System (INIS)

EI-Shanshoury, G.I.

2011-01-01

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

Real-Time Reliability Verification for UAV Flight Control System Supporting Airworthiness Certification.

Science.gov (United States)

Xu, Haiyang; Wang, Ping

2016-01-01

In order to verify the real-time reliability of unmanned aerial vehicle (UAV) flight control system and comply with the airworthiness certification standard, we proposed a model-based integration framework for modeling and verification of time property. Combining with the advantages of MARTE, this framework uses class diagram to create the static model of software system, and utilizes state chart to create the dynamic model. In term of the defined transformation rules, the MARTE model could be transformed to formal integrated model, and the different part of the model could also be verified by using existing formal tools. For the real-time specifications of software system, we also proposed a generating algorithm for temporal logic formula, which could automatically extract real-time property from time-sensitive live sequence chart (TLSC). Finally, we modeled the simplified flight control system of UAV to check its real-time property. The results showed that the framework could be used to create the system model, as well as precisely analyze and verify the real-time reliability of UAV flight control system.

Reliability test for reactor internals rejuvenation technology

International Nuclear Information System (INIS)

Uchiyama, Junichi

1998-01-01

41 transparencies were presented on the subject of 'Reliability test for reactor internals rejuvenation technology'. The items presented give an introduction on the management of plant life in Japan and introduce the Nuclear Power Engineering Corporation (NUPEC). The question of what reliability tests for rejuvenation of reactor internals are is discussed in some detail and an outline of each test is given. Altogether six methods to rejuvenate reactor internals are presented, two of which have already been applied to actual plants. The presentation was supported by many detailed drawings and images

Optimal design of a maintainable cold-standby system

Energy Technology Data Exchange (ETDEWEB)

Yu Haiyang [Universite de technologie de Troyes, ISTIT, Rue Marie Curie, BP 2060, 10010 TROYES (France)]. E-mail: Haiyang.YU@utt.fr; Yalaoui, Farouk [Universite de technologie de Troyes, ISTIT, Rue Marie Curie, BP 2060, 10010 TROYES (France); Chatelet, Eric [Universite de technologie de Troyes, ISTIT, Rue Marie Curie, BP 2060, 10010 TROYES (France); Chu Chengbin [Universite de technologie de Troyes, ISTIT, Rue Marie Curie, BP 2060, 10010 TROYES (France); Management School, Hefei University of Technology, Hefei (China)

2007-01-15

This paper considers a framework to optimally design a maintainable cold-standby system. Not only the maintenance policy is to be determined, but also the reliability character of the components will be taken into account. Hence, the mean time to failure of the components and the policy time of good-as-new maintenances are proposed as decision variables. Following probability analyses, the system cost rate and the system availability are formulated as the optimization object and the constraint, respectively. Then, this optimization problem is directly resolved by recognizing its underlying properties. Moreover, the resolving procedure is found to be independent of the failure distributions of the components and the forms of the system cost, which is illustrated through a numerical example. As a conclusion, an exact method is successfully established to minimize the cost rate of a cold-standby system with the given maintenance facility.

Optimal design of a maintainable cold-standby system

International Nuclear Information System (INIS)

Yu Haiyang; Yalaoui, Farouk; Chatelet, Eric; Chu Chengbin

2007-01-01

This paper considers a framework to optimally design a maintainable cold-standby system. Not only the maintenance policy is to be determined, but also the reliability character of the components will be taken into account. Hence, the mean time to failure of the components and the policy time of good-as-new maintenances are proposed as decision variables. Following probability analyses, the system cost rate and the system availability are formulated as the optimization object and the constraint, respectively. Then, this optimization problem is directly resolved by recognizing its underlying properties. Moreover, the resolving procedure is found to be independent of the failure distributions of the components and the forms of the system cost, which is illustrated through a numerical example. As a conclusion, an exact method is successfully established to minimize the cost rate of a cold-standby system with the given maintenance facility

Reliability demonstration of imaging surveillance systems

International Nuclear Information System (INIS)

Sheridan, T.F.; Henderson, J.T.; MacDiarmid, P.R.

1979-01-01

Security surveillance systems which employ closed circuit television are being deployed with increasing frequency for the protection of property and other valuable assets. A need exists to demonstrate the reliability of such systems before their installation to assure that the deployed systems will operate when needed with only the scheduled amount of maintenance and support costs. An approach to the reliability demonstration of imaging surveillance systems which employ closed circuit television is described. Failure definitions based on industry television standards and imaging alarm assessment criteria for surveillance systems are discussed. Test methods which allow 24 hour a day operation without the need for numerous test scenarios, test personnel and elaborate test facilities are presented. Existing reliability demonstration standards are shown to apply which obviate the need for elaborate statistical tests. The demonstration methods employed are shown to have applications in other types of imaging surveillance systems besides closed circuit television

Selenide isotope generator for the Galileo mission. Reliability program plan

International Nuclear Information System (INIS)

1978-10-01

The reliability program plan for the Selenide Isotope Generator (SIG) program is presented. It delineates the specific tasks that will be accomplished by Teledyne Energy Systems and its suppliers during design, development, fabrication and test of deliverable Radioisotopic Thermoelectric Generators (RTG), Electrical Heated Thermoelectric Generators (ETG) and associated Ground Support Equipment (GSE). The Plan is formulated in general accordance with procedures specified in DOE Reliability Engineering Program Requirements Publication No. SNS-2, dated June 17, 1974. The Reliability Program Plan presented herein defines the total reliability effort without further reference to Government Specifications. The reliability tasks to be accomplished are delineated herein and become the basis for contract compliance to the extent specified in the SIG contract Statement of Work

Mining protein interactomes to improve their reliability and support the advancement of network medicine

KAUST Repository

Alanis Lobato, Gregorio

2015-09-23

High-throughput detection of protein interactions has had a major impact in our understanding of the intricate molecular machinery underlying the living cell, and has permitted the construction of very large protein interactomes. The protein networks that are currently available are incomplete and a significant percentage of their interactions are false positives. Fortunately, the structural properties observed in good quality social or technological networks are also present in biological systems. This has encouraged the development of tools, to improve the reliability of protein networks and predict new interactions based merely on the topological characteristics of their components. Since diseases are rarely caused by the malfunction of a single protein, having a more complete and reliable interactome is crucial in order to identify groups of inter-related proteins involved in disease etiology. These system components can then be targeted with minimal collateral damage. In this article, an important number of network mining tools is reviewed, together with resources from which reliable protein interactomes can be constructed. In addition to the review, a few representative examples of how molecular and clinical data can be integrated to deepen our understanding of pathogenesis are discussed.

Mining protein interactomes to improve their reliability and support the advancement of network medicine

Directory of Open Access Journals (Sweden)

Gregorio eAlanis-Lobato

2015-09-01

Full Text Available High-throughput detection of protein interactions has had a major impact in our understanding of the intricate molecular machinery underlying the living cell, and has permitted the construction of very large protein interactomes. The protein networks that are currently available are incomplete and a significant percentage of their interactions are false positives. Fortunately, the structural properties observed in good quality social or technological networks are also present in biological systems. This has encouraged the development of tools, to improve the reliability of protein networks and predict new interactions based merely on the topological characteristics of their components. Since diseases are rarely caused by the malfunction of a single protein, having a more complete and reliable interactome is crucial in order to identify groups of inter-related proteins involved in disease aetiology. These system components can then be targeted with minimal collateral damage. In this article, an important number of network mining tools is reviewed, together with resources from which reliable protein interactomes can be constructed. In addition to the review, a few representative examples of how molecular and clinical data can be integrated to deepen our understanding of pathogenesis are discussed.

Reliability-redundancy optimization by means of a chaotic differential evolution approach

International Nuclear Information System (INIS)

Coelho, Leandro dos Santos

2009-01-01

The reliability design is related to the performance analysis of many engineering systems. The reliability-redundancy optimization problems involve selection of components with multiple choices and redundancy levels that produce maximum benefits, can be subject to the cost, weight, and volume constraints. Classical mathematical methods have failed in handling nonconvexities and nonsmoothness in optimization problems. As an alternative to the classical optimization approaches, the meta-heuristics have been given much attention by many researchers due to their ability to find an almost global optimal solution in reliability-redundancy optimization problems. Evolutionary algorithms (EAs) - paradigms of evolutionary computation field - are stochastic and robust meta-heuristics useful to solve reliability-redundancy optimization problems. EAs such as genetic algorithm, evolutionary programming, evolution strategies and differential evolution are being used to find global or near global optimal solution. A differential evolution approach based on chaotic sequences using Lozi's map for reliability-redundancy optimization problems is proposed in this paper. The proposed method has a fast convergence rate but also maintains the diversity of the population so as to escape from local optima. An application example in reliability-redundancy optimization based on the overspeed protection system of a gas turbine is given to show its usefulness and efficiency. Simulation results show that the application of deterministic chaotic sequences instead of random sequences is a possible strategy to improve the performance of differential evolution.

Durability reliability analysis for corroding concrete structures under uncertainty

Science.gov (United States)

Zhang, Hao

2018-02-01

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

Laboratory Information Management System Chain of Custody: Reliability and Security

OpenAIRE

Tomlinson, J. J.; Elliott-Smith, W.; Radosta, T.

2006-01-01

A chain of custody (COC) is required in many laboratories that handle forensics, drugs of abuse, environmental, clinical, and DNA testing, as well as other laboratories that want to assure reliability of reported results. Maintaining a dependable COC can be laborious, but with the recent establishment of the criteria for electronic records and signatures by US regulatory agencies, laboratory information management systems (LIMSs) are now being developed to fully automate COCs. The extent of a...

The development of an enhanced strain measurement device to support testing of radioactive material packages

International Nuclear Information System (INIS)

Uncapkher, W.L.; Arviso, M.

1995-01-01

Radioactive material package designers use structural testing to verify and demonstrate package performance. A major part of evaluating structural response is the collection of reliable instrumentation measurement data. Over the last four decades, Sandia National Laboratories (SNL) has been actively involved in the development, testing, and evaluation of measurement devices for a broad range of applications, resulting in the commercialization of several measurement devices commonly used today. SNL maintains an ongoing program sponsored by the US Department of Energy (DOE) to develop and evaluate measurement devices to support testing of packages used to transport radioactive or hazardous materials. The development of the enhanced strain measurement device is part of this program

The specification-based validation of reliable multicast protocol: Problem Report. M.S. Thesis

Science.gov (United States)

Wu, Yunqing

1995-01-01

Reliable Multicast Protocol (RMP) is a communication protocol that provides an atomic, totally ordered, reliable multicast service on top of unreliable IP multicasting. In this report, we develop formal models for RMP using existing automated verification systems, and perform validation on the formal RMP specifications. The validation analysis help identifies some minor specification and design problems. We also use the formal models of RMP to generate a test suite for conformance testing of the implementation. Throughout the process of RMP development, we follow an iterative, interactive approach that emphasizes concurrent and parallel progress of implementation and verification processes. Through this approach, we incorporate formal techniques into our development process, promote a common understanding for the protocol, increase the reliability of our software, and maintain high fidelity between the specifications of RMP and its implementation.

Requirements for Designing Life Support System Architectures for Crewed Exploration Missions Beyond Low-Earth Orbit

Science.gov (United States)

Howard, David; Perry,Jay; Sargusingh, Miriam; Toomarian, Nikzad

2016-01-01

NASA's technology development roadmaps provide guidance to focus technological development on areas that enable crewed exploration missions beyond low-Earth orbit. Specifically, the technology area roadmap on human health, life support and habitation systems describes the need for life support system (LSS) technologies that can improve reliability and in-situ maintainability within a minimally-sized package while enabling a high degree of mission autonomy. To address the needs outlined by the guiding technology area roadmap, NASA's Advanced Exploration Systems (AES) Program has commissioned the Life Support Systems (LSS) Project to lead technology development in the areas of water recovery and management, atmosphere revitalization, and environmental monitoring. A notional exploration LSS architecture derived from the International Space has been developed and serves as the developmental basis for these efforts. Functional requirements and key performance parameters that guide the exploration LSS technology development efforts are presented and discussed. Areas where LSS flight operations aboard the ISS afford lessons learned that are relevant to exploration missions are highlighted.

Maintaining Work: The Influence of Child Care Subsidies on Child Care-Related Work Disruptions

Science.gov (United States)

Forry, Nicole D.; Hofferth, Sandra L.

2011-01-01

With the passage of welfare reform, support for low-income parents to not only obtain but also maintain work has become imperative. The role of child care subsidies in supporting parents' job tenure has received little attention in the literature. This article examines the association between receiving a child care subsidy and experiencing a child…

Validity, reliability and support for implementation of independence-scaled procedural assessment in laparoscopic surgery.

Science.gov (United States)

Kramp, Kelvin H; van Det, Marc J; Veeger, Nic J G M; Pierie, Jean-Pierre E N

2016-06-01

There is no widely used method to evaluate procedure-specific laparoscopic skills. The first aim of this study was to develop a procedure-based assessment method. The second aim was to compare its validity, reliability and feasibility with currently available global rating scales (GRSs). An independence-scaled procedural assessment was created by linking the procedural key steps of the laparoscopic cholecystectomy to an independence scale. Subtitled and blinded videos of a novice, an intermediate and an almost competent trainee, were evaluated with GRSs (OSATS and GOALS) and the independence-scaled procedural assessment by seven surgeons, three senior trainees and six scrub nurses. Participants received a short introduction to the GRSs and independence-scaled procedural assessment before assessment. The validity was estimated with the Friedman and Wilcoxon test and the reliability with the intra-class correlation coefficient (ICC). A questionnaire was used to evaluate user opinion. Independence-scaled procedural assessment and GRS scores improved significantly with surgical experience (OSATS p = 0.001, GOALS p < 0.001, independence-scaled procedural assessment p < 0.001). The ICCs of the OSATS, GOALS and independence-scaled procedural assessment were 0.78, 0.74 and 0.84, respectively, among surgeons. The ICCs increased when the ratings of scrub nurses were added to those of the surgeons. The independence-scaled procedural assessment was not considered more of an administrative burden than the GRSs (p = 0.692). A procedural assessment created by combining procedural key steps to an independence scale is a valid, reliable and acceptable assessment instrument in surgery. In contrast to the GRSs, the reliability of the independence-scaled procedural assessment exceeded the threshold of 0.8, indicating that it can also be used for summative assessment. It furthermore seems that scrub nurses can assess the operative competence of surgical trainees.

Selective methods for the maintainability and standardization of the engineering of a research reactor

International Nuclear Information System (INIS)

Rico, N.

1999-01-01

the same function in each specialty. These diversities bring about conflicts and confusion between the maintenance and operation crew, besides modifying dangerously the fail rate and thus the overall reliability of the reactor. The maintainability is the capacity of being maintained an equipment/system has, serving as a design parameter. A system must be designed in a way in which it is maintained without a great investment of time and with low costs, minimum environmental impact and the least resources possible. Standardization is the action of normalizing the engineering of all systems/equipments of the reactor from its design, in all the disciplines, (mechanical, electrical, electronic, chemical, etc.) taking into consideration the facility of its maintenance and conserving or increasing the reliability of the system. The intention of this Program of Maintainability and Standardization in Research Reactors is based on procedures and calculations to improve the reliability of the equipments/systems according to pre-established criterion. (author)

Artificial intelligent decision support for low-cost launch vehicle integrated mission operations

Science.gov (United States)

Szatkowski, Gerard P.; Schultz, Roger

1988-01-01

The feasibility, benefits, and risks associated with Artificial Intelligence (AI) Expert Systems applied to low cost space expendable launch vehicle systems are reviewed. This study is in support of the joint USAF/NASA effort to define the next generation of a heavy-lift Advanced Launch System (ALS) which will provide economical and routine access to space. The significant technical goals of the ALS program include: a 10 fold reduction in cost per pound to orbit, launch processing in under 3 weeks, and higher reliability and safety standards than current expendables. Knowledge-based system techniques are being explored for the purpose of automating decision support processes in onboard and ground systems for pre-launch checkout and in-flight operations. Issues such as: satisfying real-time requirements, providing safety validation, hardware and Data Base Management System (DBMS) interfacing, system synergistic effects, human interfaces, and ease of maintainability, have an effect on the viability of expert systems as a useful tool.

Reliability Improved Cooperative Communication over Wireless Sensor Networks

Directory of Open Access Journals (Sweden)

Zhuangbin Chen

2017-10-01

Full Text Available With the development of smart devices and connection technologies, Wireless Sensor Networks (WSNs are becoming increasingly intelligent. New or special functions can be obtained by receiving new versions of program codes to upgrade their software systems, forming the so-called smart Internet of Things (IoT. Due to the lossy property of wireless channels, data collection in WSNs still suffers from a long delay, high energy consumption, and many retransmissions. Thanks to wireless software-defined networks (WSDNs, software in sensors can now be updated to help them transmit data cooperatively, thereby achieving more reliable communication. In this paper, a Reliability Improved Cooperative Communication (RICC data collection scheme is proposed to improve the reliability of random-network-coding-based cooperative communications in multi-hop relay WSNs without reducing the network lifetime. In WSNs, sensors in different positions can have different numbers of packets to handle, resulting in the unbalanced energy consumption of the network. In particular, nodes in non-hotspot areas have up to 90% of their original energy remaining when the network dies. To efficiently use the residual energy, in RICC, high data transmission power is adopted in non-hotspot areas to achieve a higher reliability at the cost of large energy consumption, and relatively low transmission power is adopted in hotspot areas to maintain the long network lifetime. Therefore, high reliability and a long network lifetime can be obtained simultaneously. The simulation results show that compared with other scheme, RICC can reduce the end-to-end Message Fail delivering Ratio (MFR by 59.4%–62.8% under the same lifetime with a more balanced energy utilization.

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

Power quality and reliability issues in a deregulated energy market

International Nuclear Information System (INIS)

Huggins, M.J.

1999-01-01

The challenge of maintaining power quality and reliability in Ontario's new competitive electricity market was the focus of this paper. The intention of Ontario's deregulation is to lower costs and give customers more power and choice. However, some fear that costs pressures may lead to poorer quality. This paper reviewed the causes, costs, and responsibilities, and made some suggestions concerning how customers can protect their interests as the market opens. It was suggested that in order to assure power quality, especially during the transition period, customers need to take care to design their systems and equipment to tolerate some quality variations. Conversely, utilities need to strive for at least minimum industry standards under most conditions. Contracts should be carefully crafted, with responsibilities for reliability and quality clearly stated. 2 refs

Alternative ceramic circuit constructions for low cost, high reliability applications

International Nuclear Information System (INIS)

Modes, Ch.; O'Neil, M.

1997-01-01

The growth in the use of hybrid circuit technology has recently been challenged by recent advances in low cost laminate technology, as well as the continued integration of functions into IC's. Size reduction of hybrid 'packages' has turned out to be a means to extend the useful life of this technology. The suppliers of thick film materials technology have responded to this challenge by developing a number of technology options to reduce circuit size, increase density, and reduce overall cost, while maintaining or increasing reliability. This paper provides an overview of the processes that have been developed, and, in many cases are used widely to produce low cost, reliable microcircuits. Comparisons of each of these circuit fabrication processes are made with a discussion of advantages and disadvantages of each technology. (author)

Utilizing leadership to achieve high reliability in the delivery of perinatal care

Directory of Open Access Journals (Sweden)

Parrotta C

2012-11-01

Full Text Available Carmen Parrotta,1 William Riley,1 Les Meredith21School of Public Health, University of Minnesota, Minneapolis, MN, 2Premier Insurance Management Services Inc, Charlotte, NC, USAAbstract: Highly reliable care requires standardization of clinical practices and is a prerequisite for patient safety. However, standardization in complex hospital settings is extremely difficult to attain and health care leaders are challenged to create care delivery processes that ensure patient safety. Moreover, once high reliability is achieved in a hospital unit, it must be maintained to avoid process deterioration. This case study examines an intervention to implement care bundles (a collection of evidence-based practices in four hospitals to achieve standardized care in perinatal units. The results show different patterns in the rate and magnitude of change within the hospitals to achieve high reliability. The study is part of a larger nationwide study of 16 hospitals to improve perinatal safety. Based on the findings, we discuss the role of leadership for implementing and sustaining high reliability to ensure freedom from unintended injury.Keywords: care bundles, evidence-based practice, standardized care, process improvement

The reliability of the Brazilian version of the Composite International Diagnostic Interview (CIDI 2.1

Directory of Open Access Journals (Sweden)

Quintana M.I.

2004-01-01

Full Text Available The objective of the present study was to determine the reliability of the Brazilian version of the Composite International Diagnostic Interview 2.1 (CIDI 2.1 in clinical psychiatry. The CIDI 2.1 was translated into Portuguese using WHO guidelines and reliability was studied using the inter-rater reliability method. The study sample consisted of 186 subjects from psychiatric hospitals and clinics, primary care centers and community services. The interviewers consisted of a group of 13 lay and three non-lay interviewers submitted to the CIDI training. The average interview time was 2 h and 30 min. General reliability ranged from kappa 0.50 to 1. For lifetime diagnoses the reliability ranged from kappa 0.77 (Bipolar Affective Disorder to 1 (Substance-Related Disorder, Alcohol-Related Disorder, Eating Disorders. Previous year reliability ranged from kappa 0.66 (Obsessive-Compulsive Disorder to 1 (Dissociative Disorders, Maniac Disorders, Eating Disorders. The poorest reliability rate was found for Mild Depressive Episode (kappa = 0.50 during the previous year. Training proved to be a fundamental factor for maintaining good reliability. Technical knowledge of the questionnaire compensated for the lack of psychiatric knowledge of the lay personnel. Inter-rater reliability was good to excellent for persons in psychiatric practice.

A Quantitative Risk Analysis Framework for Evaluating and Monitoring Operational Reliability of Cloud Computing

Science.gov (United States)

Islam, Muhammad Faysal

2013-01-01

Cloud computing offers the advantage of on-demand, reliable and cost efficient computing solutions without the capital investment and management resources to build and maintain in-house data centers and network infrastructures. Scalability of cloud solutions enable consumers to upgrade or downsize their services as needed. In a cloud environment,…

The order progress diagram : A supportive tool for diagnosing delivery reliability performance in make-to-order companies

NARCIS (Netherlands)

Soepenberg, G.D.; Land, M.J.; Gaalman, G.J.C.

This paper describes the development of a new tool for facilitating the diagnosis of logistic improvement opportunities in make-to-order (MTO) companies. Competitiveness of these companies increasingly imposes needs upon delivery reliability. In order to achieve high delivery reliability, both the

The use of reliability analysis techniques applied to nuclear power station emergency core cooling systems

International Nuclear Information System (INIS)

Danielsen, A.; Snaith, E.R.

1975-01-01

A reliability investigation carried out by the Safety and Reliability Services of the UKAEA, and the SSEB, of the essential system/reactor coolant system for a large nuclear power station is described. In AGR type reactors, after all reactor shutdown conditions, it is necessary to restore forced gas circulation and sufficient boiler feed to maintain the heat removal capacity of the boilers. The coolant requirements are provided by several independent mechanical systems of primary coolant fans, feedwater pumps, and valves integrated with electrical power sources, switchgear, and automatic control equipment. Reliability is treated as one aspect of system performance and quantified in terms of failure to meet a specific objective. Based on the reliability performance of the constituent components the optimum system configuration is determined together with the preferred plant operating procedures and maintenance requirements. (author)

Human Reliability Assessment and Human Performance Evaluation: Research and Analysis Activities at the U.S. NRC

International Nuclear Information System (INIS)

Ramey-Smith, A.M.

1998-01-01

The author indicates the themes of the six programs identified by the US NRC mission on human performance and human reliability activities. They aim at developing the technical basis to support human performance, at developing and updating a model of human performance and human reliability, at fostering national and international dialogue and cooperation efforts on human performance evaluation, at conducting operating events analysis and database development, and at providing support to human performance and human reliability inspection

Multinomial-exponential reliability function: a software reliability model

International Nuclear Information System (INIS)

Saiz de Bustamante, Amalio; Saiz de Bustamante, Barbara

2003-01-01

The multinomial-exponential reliability function (MERF) was developed during a detailed study of the software failure/correction processes. Later on MERF was approximated by a much simpler exponential reliability function (EARF), which keeps most of MERF mathematical properties, so the two functions together makes up a single reliability model. The reliability model MERF/EARF considers the software failure process as a non-homogeneous Poisson process (NHPP), and the repair (correction) process, a multinomial distribution. The model supposes that both processes are statistically independent. The paper discusses the model's theoretical basis, its mathematical properties and its application to software reliability. Nevertheless it is foreseen model applications to inspection and maintenance of physical systems. The paper includes a complete numerical example of the model application to a software reliability analysis

Ebb and Flow: Maintaining the Close Air Support Relationship through History

Science.gov (United States)

2016-05-10

3-09.3, Close Air Support (Washington, DC: Government Printing Office, 2014), xi. 20 Scott Fischer , LtCol, USAF, “Army and Air Force Subcultures...also happens that airmen and ground forces can 30 Jeff Schogol, "Welsh: The Air Force cares about...Advanced Military Studies, 2004), 59. 60 Fischer , “Army Air Force Subcultures,” 15. 61 Bolton, “Army Fixed-Wing Attack,” 5-6. 21 external

Reliability modeling of digital RPS with consideration of undetected software faults

Energy Technology Data Exchange (ETDEWEB)

Khalaquzzaman, M.; Lee, Seung Jun; Jung, Won Dea [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Kim, Man Cheol [Chung Ang Univ., Seoul (Korea, Republic of)

2013-10-15

This paper provides overview of different software reliability methodologies and proposes a technic for estimating the reliability of RPS with consideration of undetected software faults. Software reliability analysis of safety critical software has been challenging despite spending a huge effort for developing large number of software reliability models, and no consensus yet to attain on an appropriate modeling methodology. However, it is realized that the combined application of BBN based SDLC fault prediction method and random black-box testing of software would provide better ground for reliability estimation of safety critical software. Digitalizing the reactor protection system of nuclear power plant has been initiated several decades ago and now full digitalization has been adopted in the new generation of NPPs around the world because digital I and C systems have many better technical features like easier configurability and maintainability over analog I and C systems. Digital I and C systems are also drift-free and incorporation of new features is much easier. Rules and regulation for safe operation of NPPs are established and has been being practiced by the operators as well as regulators of NPPs to ensure safety. The failure mechanism of hardware and analog systems well understood and the risk analysis methods for these components and systems are well established. However, digitalization of I and C system in NPP introduces some crisis and uncertainty in reliability analysis methods of the digital systems/components because software failure mechanisms are still unclear.

reliability reliability

African Journals Online (AJOL)

eobe

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

About water chemistry influence on equipment reliability of NPP with RBMK-1000

International Nuclear Information System (INIS)

Berezina, I.G.; Styazhkin, P.S.; Kritskij, V.G.

2001-01-01

In the paper the experience of a quantitative valuation of coolant quality influence on a reliability of some equipment elements of NPP with RBMK-1000 is offered. The choice is made of coolant quality integral parameter. The connection between indices values of coolant quality and reliability of major elements of circulation circuit equipment (including fuel claddings) is established. The reliability improvement of equipment elements operation is supported by high water chemistry quality. (orig.)

Assessing the Reliability of Student Evaluations of Teaching: Choosing the Right Coefficient

Science.gov (United States)

Morley, Donald

2014-01-01

Many of the studies used to support the claim that student evaluations of teaching are reliable measures of teaching effectiveness have frequently calculated inappropriate reliability coefficients. This paper points to three coefficients that would be appropriate depending on if student evaluations were used for formative or summative purposes.…

The Reliability, Impact, and Cost-Effectiveness of Value-Added Teacher Assessment Methods

Science.gov (United States)

Yeh, Stuart S.

2012-01-01

This article reviews evidence regarding the intertemporal reliability of teacher rankings based on value-added methods. Value-added methods exhibit low reliability, yet are broadly supported by prominent educational researchers and are increasingly being used to evaluate and fire teachers. The article then presents a cost-effectiveness analysis…

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

Directory of Open Access Journals (Sweden)

Kang Rui

2016-06-01

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

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

Directory of Open Access Journals (Sweden)

Zahirah Alifia Maulida

2015-01-01

reliability analysis methods which purposely employed to gain a Cognitive Failure Probability (CFP value which can be conducted with basic and extended method. An application of basic method will result a general value of failure probability whereas a more specific CFP value for every task will be resulted when the extended method is utilized. This study showed that numbers of factors that shall be applied to mitigate error on grinding and welding sector are application of; adequacy of organization, adequacy of Man Machine Interface (MMI & operational support, availability of procedure /plans and adequacy of training and preparation. This study exhibites that planning has the highest erroneous value of cognitive aspect on grinding task (by CFP value of 0.3. Furthermore, CFP value of 0.18 of cognitive aspect is shown for execution on welding task. To summarize, this study suggests numerous method to trim cognitive erroneous value on grinding and welding work, which are by committing a periodical training, applying more detail work instruction and giving education to operate the equipment. Keywords: CREAM (cognitive reliability and error analysis method, HRA (human reliability analysis, cognitive error

SGHWR fuel performance, safety and reliability

International Nuclear Information System (INIS)

Pickman, D.O.; Inglis, G.H.

1977-05-01

The design principles involved in fuel pins and elements need to take account of the sometimes conflicting requirements of safety and reliability. The principal factors involved in this optimisation are discussed and it is shown from fuel irradiation experience in the Winfrith SGHWR that the necessary bias towards safety has not resulted in a reliability level lower than that shown by other successful water reactor designs. Reliability has important economic implications. By a detailed evaluation of SGHWR fuel defects it is shown that very few defects can be shown to be related to design, rating, or burn-up. This demonstrates that economic aspects have not over-ridden necessary criteria that most be met to achieve the desirable reliability level. It is possible that large scale experience on SGHWR fuel may eventually demonstrate that the balance is too much in favour of reliability and consideration may be given to whether design changes favouring economy could be achieved without compromising safety. The safety criteria applied to SGHWR fuel are designed to avoid any possibility of a temperature runaway in any credible accident situation. the philosophy and supporting experimental work programme are outlines and the fuel design features which particularly contribute to maximising safety margins are outlined. Reference is made to the new 60-pin fuel element to be used in the commercial SGHWRs and to its comparison in design and performance aspects with the 36-pin element that has been used to date in the Winfrith SGHWR. (author)

Development of the Centralized Reliability Data Organization (CREDO)

International Nuclear Information System (INIS)

Haas, P.M.; Bott, T.F.; Knee, H.E.; Manning, J.J.; Hudson, S.D.; Greene, N.M.; Woodside, M.A.

1979-01-01

CREDO has been established to meet the needs of the US Breeder Reactor Program and the advanced reactor community for a centralized source of accurate reliability/maintainability data and data-related services. The center provides for a comprehensive program of collection, evaluation, and dissemination of data and for necessary user services. A steering committee of nationally recognized experts has been formed to guide CREDO development and operation. Historic data have been collected, analyzed, and published. Routine, continuous data collection and processing has been initiated at US sites. Interfaces with existing data bases have been established. Special user services are under development

The effect of resource history on the functioning of soil microbial communities is maintained across time

Science.gov (United States)

Keiser, A. D.; Strickland, M. S.; Fierer, N.; Bradford, M. A.

2011-06-01

Historical resource conditions appear to influence microbial community function. With time, historical influences might diminish as populations respond to the contemporary environment. Alternatively, they may persist given factors such as contrasting genetic potentials for adaptation to a new environment. Using experimental microcosms, we test competing hypotheses that function of distinct soil microbial communities in common environments (H1a) converge or (H1b) remain dissimilar over time. Using a 6 × 2 (soil community inoculum × litter environment) full-factorial design, we compare decomposition rates in experimental microcosms containing grass or hardwood litter environments. After 100 days, communities that develop are inoculated into fresh litters and decomposition followed for another 100 days. We repeat this for a third, 100-day period. In each successive, 100-day period, we find higher decomposition rates (i.e. functioning) suggesting communities function better when they have an experimental history of the contemporary environment. Despite these functional gains, differences in decomposition rates among initially distinct communities persist, supporting the hypothesis that dissimilarity is maintained across time. In contrast to function, community composition is more similar following a common, experimental history. We also find that "specialization" on one experimental environment incurs a cost, with loss of function in the alternate environment. For example, experimental history of a grass-litter environment reduced decomposition when communities were inoculated into a hardwood-litter environment. Our work demonstrates experimentally that despite expectations of fast growth rates, physiological flexibility and rapid evolution, initial functional differences between microbial communities are maintained across time. These findings question whether microbial dynamics can be omitted from models of ecosystem processes if we are to predict reliably global

Genotyping cows for the reference increase reliability of genomic prediction in a small breed

DEFF Research Database (Denmark)

Thomasen, Jørn Rind; Sørensen, Anders Christian; Lund, Mogens Sandø

2013-01-01

We hypothesized that adding cows to the reference population in a breed with a small number of reference bulls would increase reliabilities of genomic breeding values and genetic gain. We tested this premise by comparing two strategies for maintaining the reference population for genetic gain......, inbreeding and reliabilities of genomic predictions: 1) Adding 60 progeny tested bulls each year (B), and 2) in addition to 60 progeny tested bulls, adding 2,000 genotyped cows per year (C). Two breeding schemes were tested: 1) A turbo scheme (T) with only genotyped young bulls used intensively, and 2...... compared to the H-B, at the same level of ∆F. T-C yielded 15% higher ∆G compared t o T-B. Changing the breeding scheme from H-B to H-C increased ∆G by 5.5%. The lowest ∆F was observed with genotyping of cows. Reliabilities of GEBV in the C schemes showed a steep increase in reliability during the first...

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

African Journals Online (AJOL)

pc

2018-03-05

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

Reliability analysis of reinforced concrete grids with nonlinear material behavior

Energy Technology Data Exchange (ETDEWEB)

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

2006-06-15

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

Frontiers of reliability

CERN Document Server

Basu, Asit P; Basu, Sujit K

1998-01-01

This volume presents recent results in reliability theory by leading experts in the world. It will prove valuable for researchers, and users of reliability theory. It consists of refereed invited papers on a broad spectrum of topics in reliability. The subjects covered include Bayesian reliability, Bayesian reliability modeling, confounding in a series system, DF tests, Edgeworth approximation to reliability, estimation under random censoring, fault tree reduction for reliability, inference about changes in hazard rates, information theory and reliability, mixture experiment, mixture of Weibul

Software reliability

CERN Document Server

Bendell, A

1986-01-01

Software Reliability reviews some fundamental issues of software reliability as well as the techniques, models, and metrics used to predict the reliability of software. Topics covered include fault avoidance, fault removal, and fault tolerance, along with statistical methods for the objective assessment of predictive accuracy. Development cost models and life-cycle cost models are also discussed. This book is divided into eight sections and begins with a chapter on adaptive modeling used to predict software reliability, followed by a discussion on failure rate in software reliability growth mo

The Need to Support and Maintain Legacy Software: Ensuring Ongoing Support for the Isotopics Codes

International Nuclear Information System (INIS)

Weber, A.-L.; Funk, P.; McGinnis, B.; Vo, D.; Wang, T.-F.; Peerani, P.; Zsigrai, J.; )

2015-01-01

Since about four decades, gamma evaluation codes for plutonium and uranium isotope abundance measurements are a key component of international, regional and domestic safeguards inspections. However, the development of these codes still relies upon a very limited number of experts. This led the safeguards authorities to express concerns, and to request continuity of knowledge and maintenance capability for the codes. The presentation describes initiatives undertaken in the past ten years to ensure ongoing support for the isotopic codes. As a follow-up to the 2005 international workshop, the IAEA issued a roadmap for future developments of gamma codes, followed by a request for support in this field to several MSSP's (namely JNT A 01684). The international working group on gamma spectrometry techniques for U and Pu isotopics (IWG-GST) was launched by the European, French and US MSSPs in 2007, to respond to the needs expressed by the IAEA and other national or international inspectorates. Its activities started with the organization in 2008 of a workshop on gamma spectrometry analysis codes for U and Pu isotopics. The working group is currently developing an international database of reference spectra that will be made available to the community of users and developers. In parallel, IRSN contributes to the JNT A 01684 by advising the IAEA on establishing a procedure for validating a new version of isotopics codes compared to the previous version. The most recent initiative, proposed by the IAEA, consists in organizing an inter-comparison exercise to assess the performances of U and Pu isotopics and mass assay techniques based on medium resolution gamma spectrometry (MRGS). All these initiatives contributed to the continuity of knowledge and maintenance of the gamma isotopic codes, but further efforts are needed to ensure the long-term sustainability of the codes. (author)

Ejectors of power plants turbine units efficiency and reliability increasing

Science.gov (United States)

Aronson, K. E.; Ryabchikov, A. Yu.; Kuptsov, V. K.; Murmanskii, I. B.; Brodov, Yu. M.; Zhelonkin, N. V.; Khaet, S. I.

2017-11-01

The functioning of steam turbines condensation systems influence on the efficiency and reliability of a power plant a lot. At the same time, the condensation system operating is provided by basic ejectors, which maintain the vacuum level in the condenser. Development of methods of efficiency and reliability increasing for ejector functioning is an actual problem of up-to-date power engineering. In the paper there is presented statistical analysis of ejector breakdowns, revealed during repairing processes, the influence of such damages on the steam turbine operating reliability. It is determined, that 3% of steam turbine equipment breakdowns are the ejector breakdowns. At the same time, about 7% of turbine breakdowns are caused by different ejector malfunctions. Developed and approved design solutions, which can increase the ejector functioning indexes, are presented. Intercoolers are designed in separated cases, so the air-steam mixture can’t move from the high-pressure zones to the low-pressure zones and the maintainability of the apparatuses is increased. By U-type tubes application, the thermal expansion effect of intercooler tubes is compensated and the heat-transfer area is increased. By the applied nozzle fixing construction, it is possible to change the distance between a nozzle and a mixing chamber (nozzle exit position) for operating performance optimization. In operating conditions there are provided experimental researches of more than 30 serial ejectors and also high-efficient 3-staged ejector EPO-3-80, designed by authors. The measurement scheme of the designed ejector includes 21 indicator. The results of experimental tests with different nozzle exit positions of the ejector EPO-3-80 stream devices are presented. The pressure of primary stream (water steam) is optimized. Experimental data are well-approved by the calculation results.

NDE reliability and advanced NDE technology validation

International Nuclear Information System (INIS)

Doctor, S.R.; Deffenbaugh, J.D.; Good, M.S.; Green, E.R.; Heasler, P.G.; Hutton, P.H.; Reid, L.D.; Simonen, F.A.; Spanner, J.C.; Vo, T.V.

1989-01-01

This paper reports on progress for three programs: (1) evaluation and improvement in nondestructive examination reliability for inservice inspection of light water reactors (LWR) (NDE Reliability Program), (2) field validation acceptance, and training for advanced NDE technology, and (3) evaluation of computer-based NDE techniques and regional support of inspection activities. The NDE Reliability Program objectives are to quantify the reliability of inservice inspection techniques for LWR primary system components through independent research and establish means for obtaining improvements in the reliability of inservice inspections. The areas of significant progress will be described concerning ASME Code activities, re-analysis of the PISC-II data, the equipment interaction matrix study, new inspection criteria, and PISC-III. The objectives of the second program are to develop field procedures for the AE and SAFT-UT techniques, perform field validation testing of these techniques, provide training in the techniques for NRC headquarters and regional staff, and work with the ASME Code for the use of these advanced technologies. The final program's objective is to evaluate the reliability and accuracy of interpretation of results from computer-based ultrasonic inservice inspection systems, and to develop guidelines for NRC staff to monitor and evaluate the effectiveness of inservice inspections conducted on nuclear power reactors. This program started in the last quarter of FY89, and the extent of the program was to prepare a work plan for presentation to and approval from a technical advisory group of NRC staff

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.

Mass and Reliability System (MaRS)

Science.gov (United States)

Barnes, Sarah

2016-01-01

The Safety and Mission Assurance (S&MA) Directorate is responsible for mitigating risk, providing system safety, and lowering risk for space programs from ground to space. The S&MA is divided into 4 divisions: The Space Exploration Division (NC), the International Space Station Division (NE), the Safety & Test Operations Division (NS), and the Quality and Flight Equipment Division (NT). The interns, myself and Arun Aruljothi, will be working with the Risk & Reliability Analysis Branch under the NC Division's. The mission of this division is to identify, characterize, diminish, and communicate risk by implementing an efficient and effective assurance model. The team utilizes Reliability and Maintainability (R&M) and Probabilistic Risk Assessment (PRA) to ensure decisions concerning risks are informed, vehicles are safe and reliable, and program/project requirements are realistic and realized. This project pertains to the Orion mission, so it is geared toward a long duration Human Space Flight Program(s). For space missions, payload is a critical concept; balancing what hardware can be replaced by components verse by Orbital Replacement Units (ORU) or subassemblies is key. For this effort a database was created that combines mass and reliability data, called Mass and Reliability System or MaRS. The U.S. International Space Station (ISS) components are used as reference parts in the MaRS database. Using ISS components as a platform is beneficial because of the historical context and the environment similarities to a space flight mission. MaRS uses a combination of systems: International Space Station PART for failure data, Vehicle Master Database (VMDB) for ORU & components, Maintenance & Analysis Data Set (MADS) for operation hours and other pertinent data, & Hardware History Retrieval System (HHRS) for unit weights. MaRS is populated using a Visual Basic Application. Once populated, the excel spreadsheet is comprised of information on ISS components including

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 ...

System Reliability Engineering

International Nuclear Information System (INIS)

Lim, Tae Jin

2005-02-01

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

Examination of the reliability and validity of the Mindful Eating Questionnaire in pregnant women.

Science.gov (United States)

Apolzan, John W; Myers, Candice A; Cowley, Amanda D; Brady, Heather; Hsia, Daniel S; Stewart, Tiffany M; Redman, Leanne M; Martin, Corby K

2016-05-01

Mindfulness is theorized to affect the eating behavior and weight of pregnant women, yet no measure has been validated during pregnancy. This study qualitatively and quantitatively evaluated the reliability and validity of the Mindful Eating Questionnaire (MEQ) in overweight and obese pregnant women. Participants completed focus groups and cognitive interviews. The MEQ was administered twice to measure test-retest reliability. The Eating Inventory (EI) and Mindful Attention Awareness Scale (MAAS) were administered to assess convergent validity, and the Neighborhood Environment Walkability Scale (NEWS) assessed discriminant validity. Participants were 20 ± 8 weeks gestation (mean ± SD), 30 ± 2 years old, and 55% were obese. The MEQ total score had good test-retest reliability (r = .85). The total score internal consistency reliability was poor (Cronbach's α = .56). The external cues subscale (ECS) was not internally consistent (α = .31). Other subscales ranged from α = .59-.68. When the ECS was excluded, the MEQ total score internal consistency was acceptable (α = .62). Convergent validity was supported by the MEQ total score (with and without ECS) correlating significantly with the MAAS and the EI disinhibition and hunger subscales. Discriminant validity of the MEQ was supported by the MEQ and NEWS total scores and subscales not being significantly correlated. The quantitative results were supported by the qualitative context and content analysis. With the exception of the ECS, the MEQ's reliability and validity was supported in pregnant women, and most of the subscales were more robust in pregnant women than in the original sample of healthy adults. The MEQ's use with overweight and obese pregnant women is supported. Copyright © 2016 Elsevier Ltd. All rights reserved.

Reliability methods in nuclear power plant ageing management

International Nuclear Information System (INIS)

Simola, K.

1999-01-01

The aim of nuclear power plant ageing management is to maintain an adequate safety level throughout the lifetime of the plant. In ageing studies, the reliability of components, systems and structures is evaluated taking into account the possible time-dependent degradation. The phases of ageing analyses are generally the identification of critical components, identification and evaluation of ageing effects, and development of mitigation methods. This thesis focuses on the use of reliability methods and analyses of plant- specific operating experience in nuclear power plant ageing studies. The presented applications and method development have been related to nuclear power plants, but many of the approaches can also be applied outside the nuclear industry. The thesis consists of a summary and seven publications. The summary provides an overview of ageing management and discusses the role of reliability methods in ageing analyses. In the publications, practical applications and method development are described in more detail. The application areas at component and system level are motor-operated valves and protection automation systems, for which experience-based ageing analyses have been demonstrated. Furthermore, Bayesian ageing models for repairable components have been developed, and the management of ageing by improving maintenance practices is discussed. Recommendations for improvement of plant information management in order to facilitate ageing analyses are also given. The evaluation and mitigation of ageing effects on structural components is addressed by promoting the use of probabilistic modelling of crack growth, and developing models for evaluation of the reliability of inspection results. (orig.)

Reliability methods in nuclear power plant ageing management

Energy Technology Data Exchange (ETDEWEB)

Simola, K. [VTT Automation, Espoo (Finland). Industrial Automation

1999-07-01

The aim of nuclear power plant ageing management is to maintain an adequate safety level throughout the lifetime of the plant. In ageing studies, the reliability of components, systems and structures is evaluated taking into account the possible time-dependent degradation. The phases of ageing analyses are generally the identification of critical components, identification and evaluation of ageing effects, and development of mitigation methods. This thesis focuses on the use of reliability methods and analyses of plant- specific operating experience in nuclear power plant ageing studies. The presented applications and method development have been related to nuclear power plants, but many of the approaches can also be applied outside the nuclear industry. The thesis consists of a summary and seven publications. The summary provides an overview of ageing management and discusses the role of reliability methods in ageing analyses. In the publications, practical applications and method development are described in more detail. The application areas at component and system level are motor-operated valves and protection automation systems, for which experience-based ageing analyses have been demonstrated. Furthermore, Bayesian ageing models for repairable components have been developed, and the management of ageing by improving maintenance practices is discussed. Recommendations for improvement of plant information management in order to facilitate ageing analyses are also given. The evaluation and mitigation of ageing effects on structural components is addressed by promoting the use of probabilistic modelling of crack growth, and developing models for evaluation of the reliability of inspection results. (orig.)

THERMAL AND THERMO-MECHANICAL CHARACTERISTICS OF CRYOGENIC MICROCOOLER FOR OPTIMUM PERFORMANCE AND RELIABILITY

Science.gov (United States)

2017-10-19

reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of...contracted fundamental research deemed exempt from public affairs security and policy review in accordance with SAF/AQR memorandum dated 10 Dec 08 and AFRL...subjected to cryogenic operating conditions was assessed by proposing a hierarchical physics -of-failure-based reliability assessment model. 15. SUBJECT

NASA Advanced Exploration Systems: Advancements in Life Support Systems

Science.gov (United States)

Shull, Sarah A.; Schneider, Walter F.

2016-01-01

The NASA Advanced Exploration Systems (AES) Life Support Systems (LSS) project strives to develop reliable, energy-efficient, and low-mass spacecraft systems to provide environmental control and life support systems (ECLSS) critical to enabling long duration human missions beyond low Earth orbit (LEO). Highly reliable, closed-loop life support systems are among the capabilities required for the longer duration human space exploration missions assessed by NASA’s Habitability Architecture Team.

Reliability study: raw and make-up water system, Portsmouth Gaseous Diffusion Plant

International Nuclear Information System (INIS)

Peterman, S.M.; Wiehle, W.E.; Walder, A.; Houk, T.C.; West, R.M.

1981-09-01

A reliability study for determining the ability of the raw and make-up water system to provide reliable and adequate service through the year 2000 has been completed. This study includes an evaluation of the well fields, X-608 Raw Water Pump House, X-605 Booster Station Complex, X-611 Water Treatment Complex, and the associated piping. The raw and make-up water system is in good overall condition, but to maintain this condition, the reliability study team made the following recommendations: (1) increase well field capacity; (2) replace certain speed reducers at X-611; (3) repair deteriorated poles, crossarms, and accessories on F-2 and W-1 feeders; (4) stabilize the landslide in vicinity of the 48 in. raw water main; and (5) initiate further investigation, testing, or engineering studies to correct deficiencies in the supervisory control system between well fields, pump house, and X-611, and determine if the 2400 volt underground cables to X-608A wells should be replaced

[How Reliable is Neuronavigation?].

Science.gov (United States)

Stieglitz, Lennart Henning

2016-02-17

Neuronavigation plays a central role in modern neurosurgery. It allows visualizing instruments and three-dimensional image data intraoperatively and supports spatial orientation. Thus it allows to reduce surgical risks and speed up complex surgical procedures. The growing availability and importance of neuronavigation makes clear how relevant it is to know about its reliability and accuracy. Different factors may influence the accuracy during the surgery unnoticed, misleading the surgeon. Besides the best possible optimization of the systems themselves, a good knowledge about its weaknesses is mandatory for every neurosurgeon.

Reliability analysis for the quench detection in the LHC machine

CERN Document Server

Denz, R; Vergara-Fernández, A

2002-01-01

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

DIRAC: reliable data management for LHCb

International Nuclear Information System (INIS)

Smith, A C; Tsaregorodtsev, A

2008-01-01

DIRAC, LHCb's Grid Workload and Data Management System, utilizes WLCG resources and middleware components to perform distributed computing tasks satisfying LHCb's Computing Model. The Data Management System (DMS) handles data transfer and data access within LHCb. Its scope ranges from the output of the LHCb Online system to Grid-enabled storage for all data types. It supports metadata for these files in replica and bookkeeping catalogues, allowing dataset selection and localization. The DMS controls the movement of files in a redundant fashion whilst providing utilities for accessing all metadata. To do these tasks effectively the DMS requires complete self integrity between its components and external physical storage. The DMS provides highly redundant management of all LHCb data to leverage available storage resources and to manage transient errors in underlying services. It provides data driven and reliable distribution of files as well as reliable job output upload, utilizing VO Boxes at LHCb Tier1 sites to prevent data loss. This paper presents several examples of mechanisms implemented in the DMS to increase reliability, availability and integrity, highlighting successful design choices and limitations discovered

NDT Reliability - Final Report. Reliability in non-destructive testing (NDT) of the canister components

Energy Technology Data Exchange (ETDEWEB)

Pavlovic, Mato; Takahashi, Kazunori; Mueller, Christina; Boehm, Rainer (BAM, Federal Inst. for Materials Research and Testing, Berlin (Germany)); Ronneteg, Ulf (Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden))

2008-12-15

This report describes the methodology of the reliability investigation performed on the ultrasonic phased array NDT system, developed by SKB in collaboration with Posiva, for inspection of the canisters for permanent storage of nuclear spent fuel. The canister is composed of a cast iron insert surrounded by a copper shell. The shell is composed of the tube and the lid/base which are welded to the tube after the fuel has been place, in the tube. The manufacturing process of the canister parts and the welding process are described. Possible defects, which might arise in the canister components during the manufacturing or in the weld during the welding, are identified. The number of real defects in manufactured components have been limited. Therefore the reliability of the NDT system has been determined using a number of test objects with artificial defects. The reliability analysis is based on the signal response analysis. The conventional signal response analysis is adopted and further developed before applied on the modern ultrasonic phased-array NDT system. The concept of multi-parameter a, where the response of the NDT system is dependent on more than just one parameter, is introduced. The weakness of use of the peak signal response in the analysis is demonstrated and integration of the amplitudes in the C-scan is proposed as an alternative. The calculation of the volume POD, when the part is inspected with more configurations, is also presented. The reliability analysis is supported by the ultrasonic simulation based on the point source synthesis method

The solution of the reliability problem in the repair process of the plates of the silica bricks press boxes

Directory of Open Access Journals (Sweden)

Nochvai V.М.

2017-05-01

Full Text Available The research analyzes recommendations existing in different sources of information for the choice of methods of strengthening and reconditioning of worn machine parts. These methods include: the method of electric arc deposition, chemical-thermal treatment, gas-powder deposition, gas-powder and plasma spraying, electric arc metallization. As a result of studies of wear of the working surfaces of the plates of silicate brick press boxes, we define that the plates wear out unevenly and the thickness of the worn layer varies between 0.3 ... 2 mm. Technological method is chosen as the method of the plate reliability enhancement and maintaining. One of the main technological stages of reliability formation is machine parts strengthening using the methods of strengthening technologies, namely electric arc metallization. Wire models Нп-65Г, ФМИ-2, Нп-40Х13 are used to develop wear-resistant coatings with desired properties. Technological process of the plates repair consists of the following basic operations: plate preparation, wire preparation, plate coating, plate grinding, final checking. Single and complex reliability indicators are determined by testing a set of the plates and registering all the indicators (operating time, failures, faults. The value of the economic reliability index of the plate Kе equals to 0,10. Higher plate reliability is achieved at the expense of extra cost for plate strengthening using wire Нп-40Х13, and the price of Bн plate reliability is 104,83 UAH. Complex indicators of reliability of the reconditioned plate of the silica bricks press boxes are used for more complete reliability assessment. Availability coefficient Kг. equals to 0,995 and characterizes two different properties simultaneously: reliability and maintainability. Coefficient of technical use Kт.в. equals to 0,974 and most fully characterizes the reliability of the plates because it considers time in the process of maintenance, repair and

A reliability simulation language for reliability analysis

International Nuclear Information System (INIS)

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

1986-01-01

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

A study of operational and testing reliability in software reliability analysis

International Nuclear Information System (INIS)

Yang, B.; Xie, M.

2000-01-01

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

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)

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

DEFF Research Database (Denmark)

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

2012-01-01

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

Effectiveness of different approaches to disseminating traveler information on travel time reliability. [supporting datasets

Science.gov (United States)

2013-11-30

Travel time reliability information includes static data about traffic speeds or trip times that capture historic variations from day to day, and it can help individuals understand the level of variation in traffic. Unlike real-time travel time infor...

Reliability engineering. Theory and practice. 6. ed.

Energy Technology Data Exchange (ETDEWEB)

Birolini, Alessandro

2010-07-01

This book shows how to build in, evaluate, and demonstrate reliability and availability of components, equipment, systems. It presents the state-of-the-art of reliability engineering, both in theory and practice, and is based on the author's 30 years experience in this field, half in industry and half as Professor of Reliability Engineering at the ETH, Zurich. The structure of the book allows rapid access to practical results. Besides extensions to cost models and approximate expressions, new in this edition are investigations on common cause failures, phased-mission systems, availability demonstration and estimation, confidence limits at system level, trend tests for early failures or wearout, as well as a review of maintenance strategies, an introduction to Petri nets and dynamic FTA, and a set of problems for home-work. Methods and tools are given in a way that they can be tailored to cover different reliability requirement levels and be used for safety analysis as well. This book is a textbook establishing a link between theory and practice, with a large number of tables, figures, and examples to support the practical aspects. (orig.)

Improvement of plant reliability in PT. Badak LNG plant

International Nuclear Information System (INIS)

Achmad, S.; Somantri, A.

1997-01-01

PT. Badak's LNG sales commitment has been steadily increasing, therefore, there has been more emphasis to improve and maintain the LNG plant reliability. From plant operation historical records, Badak LNG plant experienced a high number of LNG process train trips and down time for 1977 through 1988. The highest annual number of LNG plant trips (50 times) occurred in 1983 and the longest LNG process train down time (1259 train-hours) occurred in 1988. Since 1989, PT. Badak has been able to reduce the number of LNG process train trips and down time significantly. In 1994 the number of LNG process train trips and was 18 times and the longest LNG process train down time was 377 train-hours. This plant reliability improvement was achieved by implementing plant reliability improvement programs beginning with the design of the new facilities and continuing with the maintenance and modification of the existing facilities. To improve reliability of the existing facilities, PT. Badak has been implementing comprehensive maintenance programs, to reduce the frequency and down time of the plant, such as Preventive and Predictive Maintenance as well as procurement material improvement since PT. Badak location is in a remote area. By implementing the comprehensive reliability maintenance, PT. Badak has been able to reduce the LNG process train trips to 18 and down time to 337 train hours in 1994 with the subsequent maintenance cost reduction. The average PT. Badak plant availability from 1985 to 1995 is 94.59%. New facilities were designed according to the established PT. Badak design philosophy, master plan and specification. Design of new facilities was modified to avoid certain problems from past experience. (au)

Reliable implementation of evidence: a qualitative study of antenatal corticosteroid administration in Ohio hospitals.

Science.gov (United States)

Kaplan, Heather C; Sherman, Susan N; Cleveland, Charlena; Goldenhar, Linda M; Lannon, Carole M; Bailit, Jennifer L

2016-03-01

Antenatal corticosteroids (ANCS) reduce complications of preterm birth; however, not all eligible women receive them. Many hospitals and providers do not have the right processes and conditions to enable ANCS administration with high reliability. The objective of this study was to understand conditions that enable delivery of ANCS with high reliability among hospitals participating in an Ohio Perinatal Quality Collaborative (OPQC) ANCS project. We conducted focus groups and semistructured interviews with members of the OPQC project team (n=27) and other care providers (n=70) using a purposeful sample of 6 sites involved in the OPQC ANCS project. Participants including nurses (n=57), attending obstetricians (n=17), physician trainees (n=21) and certified nurse midwives (n=2) were asked to reflect on their experiences and to identify factors contributing to optimal use of ANCS. Focus groups and interviews were transcribed verbatim and were analysed by a multidisciplinary team using an iterative approach that combined inductive and deductive methods to identify and categorise themes. Six major themes supporting reliable implementation of ANCS at these hospitals emerged including: (1) presence of a high reliability culture, (2) processes that emphasise high reliability, (3) timely and efficient administration process, (4) multiple disciplines are involved, (5) evidence of benefit supports ANCS use and (6) benefit is recognised at all levels of the care team. Our findings identify the key processes and supports needed to ensure delivery of ASCS with high reliability and are reinforced by implementation and reliability science. They are useful for foundation of the successful implementation of other evidence-based practices at high levels of reliability. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Reliability Calculations

DEFF Research Database (Denmark)

Petersen, Kurt Erling

1986-01-01

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

Medial tibial stress syndrome can be diagnosed reliably using history and physical examination

NARCIS (Netherlands)

Winters, M.; Bakker, E. W. P.; Moen, M. H.; Barten, C. C.; Teeuwen, R.; Weir, A.

2017-01-01

The majority of sporting injuries are clinically diagnosed using history and physical examination as the cornerstone. There are no studies supporting the reliability of making a clinical diagnosis of medial tibial stress syndrome (MTSS). Our aim was to assess if MTSS can be diagnosed reliably, using

Long-term reliability of the visual EEG Poffenberger paradigm.

Science.gov (United States)

Friedrich, Patrick; Ocklenburg, Sebastian; Mochalski, Lisa; Schlüter, Caroline; Güntürkün, Onur; Genc, Erhan

2017-07-14

The Poffenberger paradigm is a simple perception task that is used to estimate the speed of information transfer between the two hemispheres, the so-called interhemispheric transfer time (IHTT). Although the original paradigm is a behavioral task, it can be combined with electroencephalography (EEG) to assess the underlying neurophysiological processes during task execution. While older studies have supported the validity of both paradigms for investigating interhemispheric interactions, their long-term reliability has not been assessed systematically before. The present study aims to fill this gap by determining both internal consistency and long-term test-retest reliability of IHTTs produced by using the two different versions of the Poffenberger paradigm in a sample of 26 healthy subjects. The results show high reliability for the EEG Poffenberger paradigm. In contrast, reliability measures for the behavioral Poffenberger paradigm were low. Hence, our results indicate that electrophysiological measures of interhemispheric transfer are more reliable than behavioral measures; the later should be used with caution in research investigating inter-individual differences of neurocognitive measures. Copyright © 2017 Elsevier B.V. All rights reserved.

Reliability and accuracy of Crystaleye spectrophotometric system.

Science.gov (United States)

Chen, Li; Tan, Jian Guo; Zhou, Jian Feng; Yang, Xu; Du, Yang; Wang, Fang Ping

2010-01-01

to develop an in vitro shade-measuring model to evaluate the reliability and accuracy of the Crystaleye spectrophotometric system, a newly developed spectrophotometer. four shade guides, VITA Classical, VITA 3D-Master, Chromascop and Vintage Halo NCC, were measured with the Crystaleye spectrophotometer in a standardised model, ten times for 107 shade tabs. The shade-matching results and the CIE L*a*b* values of the cervical, body and incisal regions for each measurement were automatically analysed using the supporting software. Reliability and accuracy were calculated for each shade tab both in percentage and in colour difference (ΔE). Difference was analysed by one-way ANOVA in the cervical, body and incisal regions. range of reliability was 88.81% to 98.97% and 0.13 to 0.24 ΔE units, and that of accuracy was 44.05% to 91.25% and 1.03 to 1.89 ΔE units. Significant differences in reliability and accuracy were found between the body region and the cervical and incisal regions. Comparisons made among regions and shade guides revealed that evaluation in ΔE was prone to disclose the differences. measurements with the Crystaleye spectrophotometer had similar, high reliability in different shade guides and regions, indicating predictable repeated measurements. Accuracy in the body region was high and less variable compared with the cervical and incisal regions.

Validity and Reliability in Social Science Research

Science.gov (United States)

Drost, Ellen A.

2011-01-01

In this paper, the author aims to provide novice researchers with an understanding of the general problem of validity in social science research and to acquaint them with approaches to developing strong support for the validity of their research. She provides insight into these two important concepts, namely (1) validity; and (2) reliability, and…

30 CFR 817.181 - Support facilities.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Support facilities. 817.181 Section 817.181... ACTIVITIES § 817.181 Support facilities. (a) Support facilities shall be operated in accordance with a permit.... (b) In addition to the other provisions of this part, support facilities shall be located, maintained...

Optimization of reliability centered predictive maintenance scheme for inertial navigation system

International Nuclear Information System (INIS)

Jiang, Xiuhong; Duan, Fuhai; Tian, Heng; Wei, Xuedong

2015-01-01

The goal of this study is to propose a reliability centered predictive maintenance scheme for a complex structure Inertial Navigation System (INS) with several redundant components. GO Methodology is applied to build the INS reliability analysis model—GO chart. Components Remaining Useful Life (RUL) and system reliability are updated dynamically based on the combination of components lifetime distribution function, stress samples, and the system GO chart. Considering the redundant design in INS, maintenance time is based not only on components RUL, but also (and mainly) on the timing of when system reliability fails to meet the set threshold. The definition of components maintenance priority balances three factors: components importance to system, risk degree, and detection difficulty. Maintenance Priority Number (MPN) is introduced, which may provide quantitative maintenance priority results for all components. A maintenance unit time cost model is built based on components MPN, components RUL predictive model and maintenance intervals for the optimization of maintenance scope. The proposed scheme can be applied to serve as the reference for INS maintenance. Finally, three numerical examples prove the proposed predictive maintenance scheme is feasible and effective. - Highlights: • A dynamic PdM with a rolling horizon is proposed for INS with redundant components. • GO Methodology is applied to build the system reliability analysis model. • A concept of MPN is proposed to quantify the maintenance sequence of components. • An optimization model is built to select the optimal group of maintenance components. • The optimization goal is minimizing the cost of maintaining system reliability

Reliability studies of diagnostic methods in Indian traditional Ayurveda medicine: An overview

Science.gov (United States)

Kurande, Vrinda Hitendra; Waagepetersen, Rasmus; Toft, Egon; Prasad, Ramjee

2013-01-01

Recently, a need to develop supportive new scientific evidence for contemporary Ayurveda has emerged. One of the research objectives is an assessment of the reliability of diagnoses and treatment. Reliability is a quantitative measure of consistency. It is a crucial issue in classification (such as prakriti classification), method development (pulse diagnosis), quality assurance for diagnosis and treatment and in the conduct of clinical studies. Several reliability studies are conducted in western medicine. The investigation of the reliability of traditional Chinese, Japanese and Sasang medicine diagnoses is in the formative stage. However, reliability studies in Ayurveda are in the preliminary stage. In this paper, examples are provided to illustrate relevant concepts of reliability studies of diagnostic methods and their implication in practice, education, and training. An introduction to reliability estimates and different study designs and statistical analysis is given for future studies in Ayurveda. PMID:23930037

Power system reliability impacts of wind generation and operational reserve requirements

Directory of Open Access Journals (Sweden)

Esteban Gil

2015-06-01

Full Text Available Due to its variability, wind generation integration presents a significant challenge to power system operators in order to maintain adequate reliability levels while ensuring least cost operation. This paper explores the trade-off between the benefits associated to a higher wind penetration and the additional operational reserve requirements that they impose. Such exploration is valued in terms of its effect on power system reliability, measured as an amount of unserved energy. The paper also focuses on how changing the Value of Lost Load (VoLL can be used to attain different reliability targets, and how wind power penetration and the diversity of the wind energy resource will impact quality of supply (in terms of instances of unserved energy. The evaluation of different penetrations of wind power generation, different wind speed profiles, wind resource diversity, and different operational reserve requirements, is conducted on the Chilean Northern Interconnected System (SING using statistical modeling of wind speed time series and computer simulation through a 24-hour ahead unit commitment algorithm and a Monte Carlo simulation scheme. Results for the SING suggest that while wind generation can significantly reduce generation costs, it can also imply higher security costs to reach acceptable reliability levels.

Multi-Voxel Decoding and the Topography of Maintained Information During Visual Working Memory.

Science.gov (United States)

Lee, Sue-Hyun; Baker, Chris I

2016-01-01

The ability to maintain representations in the absence of external sensory stimulation, such as in working memory, is critical for guiding human behavior. Human functional brain imaging studies suggest that visual working memory can recruit a network of brain regions from visual to parietal to prefrontal cortex. In this review, we focus on the maintenance of representations during visual working memory and discuss factors determining the topography of those representations. In particular, we review recent studies employing multi-voxel pattern analysis (MVPA) that demonstrate decoding of the maintained content in visual cortex, providing support for a "sensory recruitment" model of visual working memory. However, there is some evidence that maintained content can also be decoded in areas outside of visual cortex, including parietal and frontal cortex. We suggest that the ability to maintain representations during working memory is a general property of cortex, not restricted to specific areas, and argue that it is important to consider the nature of the information that must be maintained. Such information-content is critically determined by the task and the recruitment of specific regions during visual working memory will be both task- and stimulus-dependent. Thus, the common finding of maintained information in visual, but not parietal or prefrontal, cortex may be more of a reflection of the need to maintain specific types of visual information and not of a privileged role of visual cortex in maintenance.

Multi-voxel decoding and the topography of maintained information during visual working memory

Directory of Open Access Journals (Sweden)

Sue-Hyun eLee

2016-02-01

Full Text Available The ability to maintain representations in the absence of external sensory stimulation, such as in working memory, is critical for guiding human behavior. Human functional brain imaging studies suggest that visual working memory can recruit a network of brain regions from visual to parietal to prefrontal cortex. In this review, we focus on the maintenance of representations during visual working memory and discuss factors determining the topography of those representations. In particular, we review recent studies employing multi-voxel pattern analysis that demonstrate decoding of the maintained content in visual cortex, providing support for a ‘sensory recruitment’ model of visual working memory. However, there is some evidence that maintained content can also be decoded in areas outside of visual cortex, including parietal and frontal cortex. We suggest that the ability to maintain representations during working memory is a general property of cortex, not restricted to specific areas, and argue that it is important to consider the nature of the information that must be maintained. Such information-content is critically determined by the task and the recruitment of specific regions during visual working memory will be both task- and stimulus-dependent. Thus, the common finding of maintained information in visual, but not parietal or prefrontal, cortex may be more of a reflection of the need to maintain specific types of visual information and not of a privileged role of visual cortex in maintenance.

Multi-Voxel Decoding and the Topography of Maintained Information During Visual Working Memory

Science.gov (United States)

Lee, Sue-Hyun; Baker, Chris I.

2016-01-01

The ability to maintain representations in the absence of external sensory stimulation, such as in working memory, is critical for guiding human behavior. Human functional brain imaging studies suggest that visual working memory can recruit a network of brain regions from visual to parietal to prefrontal cortex. In this review, we focus on the maintenance of representations during visual working memory and discuss factors determining the topography of those representations. In particular, we review recent studies employing multi-voxel pattern analysis (MVPA) that demonstrate decoding of the maintained content in visual cortex, providing support for a “sensory recruitment” model of visual working memory. However, there is some evidence that maintained content can also be decoded in areas outside of visual cortex, including parietal and frontal cortex. We suggest that the ability to maintain representations during working memory is a general property of cortex, not restricted to specific areas, and argue that it is important to consider the nature of the information that must be maintained. Such information-content is critically determined by the task and the recruitment of specific regions during visual working memory will be both task- and stimulus-dependent. Thus, the common finding of maintained information in visual, but not parietal or prefrontal, cortex may be more of a reflection of the need to maintain specific types of visual information and not of a privileged role of visual cortex in maintenance. PMID:26912997

Perceived parenting style and mother’s behavior in maintaining dental health of children with Down syndrome

Directory of Open Access Journals (Sweden)

Siti Fitria Ulfah

2016-12-01

Full Text Available Background: The number of children with down syndrome in Surabaya has reached 924 children. Prevalence of gingivitis and dental caries (91% and 93.8%, respectively occurs in children with down syndrome aged 6 to 20 years. Oral and dental health problems are found in children with down syndrome because they have physical and motoric limitation in maintaining oral and dental hygiene, thus require parental care from mother. Perceived parenting style includes responsiveness and demandingness. Perceived parenting is crucial for mother whose children have Down syndrome in order to guide their health behavior, particularly to maintain oral and dental health. Purpose: The study aimed to analyze correlation between perceived parenting style and mother’s behavior in maintaining dental health of children with Down syndrome. Method: This cross sectional analytical study involved 40 mothers of children aged 7-13 years with Down syndrome enrolled in Special Education Elementary Schools Surabaya and Association of Parents of Children with Down syndrome Surabaya. Data of perceived parenting style (responsiveness and demandingness and mother’s behavior in maintaining dental health were obtained by questionnaire. Composition of each item in questionnaire of perceived parenting style and mother’s behavior in maintaining dental health of children with Down syndrome was passed through validity and reliability test. Data analysis was carried out using multiple linear regression correlation test. Result: This present study showed that perceived parenting style is significantly correlated with mother’s behavior in maintaining dental health of children with Down syndrome (R = 0.630, p = 0.000, with perceived parental responsiveness as a strong predictor. Mean score and standard deviation of perceived parental responsiveness and demandingness were 33.00±2.99 and 15.55±1.99, respectively. Conclusion: Perceived maternal parenting style in children with Down

Managing Stress and Maintaining Well-Being: Social Support, Problem-Focused Coping, and Avoidant Coping

Science.gov (United States)

Chao, Ruth Chu-Lien

2011-01-01

This study tested a model that links stress, social support, problem-focused coping, and well-being. First, it looks at how high support significantly moderated the association between stress and well-being. Next, the students' problem-focused coping was seen as mediating this moderated association. Finally, a 3-way interaction of stress, social…

Reliability in the utility computing era: Towards reliable Fog computing

DEFF Research Database (Denmark)

Madsen, Henrik; Burtschy, Bernard; Albeanu, G.

2013-01-01

This paper considers current paradigms in computing and outlines the most important aspects concerning their reliability. The Fog computing paradigm as a non-trivial extension of the Cloud is considered and the reliability of the networks of smart devices are discussed. Combining the reliability...... requirements of grid and cloud paradigms with the reliability requirements of networks of sensor and actuators it follows that designing a reliable Fog computing platform is feasible....

Assessing Reliability of Cellulose Hydrolysis Models to Support Biofuel Process Design – Identifiability and Uncertainty Analysis

DEFF Research Database (Denmark)

Sin, Gürkan; Meyer, Anne S.; Gernaey, Krist

2010-01-01

The reliability of cellulose hydrolysis models is studied using the NREL model. An identifiability analysis revealed that only 6 out of 26 parameters are identifiable from the available data (typical hydrolysis experiments). Attempting to identify a higher number of parameters (as done in the ori......The reliability of cellulose hydrolysis models is studied using the NREL model. An identifiability analysis revealed that only 6 out of 26 parameters are identifiable from the available data (typical hydrolysis experiments). Attempting to identify a higher number of parameters (as done...

Dependent systems reliability estimation by structural reliability approach

DEFF Research Database (Denmark)

Kostandyan, Erik; Sørensen, John Dalsgaard

2014-01-01

Estimation of system reliability by classical system reliability methods generally assumes that the components are statistically independent, thus limiting its applicability in many practical situations. A method is proposed for estimation of the system reliability with dependent components, where...... the leading failure mechanism(s) is described by physics of failure model(s). The proposed method is based on structural reliability techniques and accounts for both statistical and failure effect correlations. It is assumed that failure of any component is due to increasing damage (fatigue phenomena...... identification. Application of the proposed method can be found in many real world systems....

RFA-based 589-nm guide star lasers for ESO VLT: a paradigm shift in performance, operational simplicity, reliability, and maintenance

Science.gov (United States)

Friedenauer, Axel; Karpov, Vladimir; Wei, Daoping; Hager, Manfred; Ernstberger, Bernhard; Clements, Wallace R. L.; Kaenders, Wilhelm G.

2012-07-01

Large telescopes equipped with adaptive optics require 20-25W CW 589-nm sources with emission linewidths of ~5 MHz. These Guide Star (GS) lasers should also be highly reliable and simple to operate and maintain for many years at the top of a mountain facility. Under contract from ESO, industrial partners TOPTICA and MPBC are nearing completion of the development of GS lasers for the ESO VLT, with delivery of the first of four units scheduled for December 2012. We report on the design and performance of the fully-engineered Pre-Production Unit (PPU), including system reliability/availability analysis, the successfully-concluded qualification testing, long-term component and system level tests and long-term maintenance and support planning. The chosen approach is based on ESO's patented narrow-band Raman Fiber Amplifier (EFRA) technology. A master oscillator signal from a linearly-polarized TOPTICA 20-mW, 1178-nm CW diode laser, with stabilized emission frequency and controllable linewidth up to a few MHz, is amplified in an MPBC polarization-maintaining (PM) RFA pumped by a high-power 1120-nm PM fiber laser. With efficient stimulated Brillouin scattering suppression, an unprecedented 40W of narrow-band RFA output has been obtained. This is then mode-matched into a resonant-cavity doubler with a free-spectral-range matching the sodium D2a to D2b separation, allowing simultaneous generation of an additional frequency component (D2b line) to re-pump the sodium atom electronic population. With this technique, the return flux can be increased without having to resort to electro-optical modulators and without the risk of introducing optical wave front distortions. The demonstrated output powers with doubling efficiencies >80% at 589 nm easily exceed the 20W design goal and require less than 700 W of electrical power. In summary, the fiber-based guide star lasers provide excellent beam quality and are modular, turn-key, maintenance-free, reliable, efficient, and ruggedized

Reliability Based Optimization of Fire Protection

DEFF Research Database (Denmark)

Thoft-Christensen, Palle

fire protection (PFP) of firewalls and structural members. The paper is partly based on research performed within the EU supported research project B/E-4359 "Optimized Fire Safety of Offshore Structures" and partly on research supported by the Danish Technical Research Council (see Thoft-Christensen [1......]). Special emphasis is put on the optimization software developed within the project.......It is well known that fire is one of the major risks of serious damage or total loss of several types of structures such as nuclear installations, buildings, offshore platforms/topsides etc. This paper presents a methodology and software for reliability based optimization of the layout of passive...

Selection, design, qualification, testing, and reliability of emergency diesel generator units used as Class 1E onsite electric power systems at nuclear power plants

International Nuclear Information System (INIS)

1992-04-01

This guide has been prepared for the resolution of Generic Safety Issue B-56, ''Diesel Generator Reliability,'' and is related to Unresolved Safety Issue (USI) A-44, ''Station Blackout.'' The resolution of USI A-44 established a need for an emergency diesel generator (EDG) reliability program that has the capability to achieve and maintain the emergency diesel generator reliability levels in the range of 0.95 per demand or better to cope with station blackout

Reliability of containment and safety-related structures

International Nuclear Information System (INIS)

Nessim, M.A.

1995-09-01

A research program on Reliability of Containment and Safety-related Structures has been developed and is described in this document. This program is designed to support AECB's regulatory activities aimed at ensuring the safety of these structures. These activities include evaluating submissions by operators and requesting special assessments when necessary. The results of the proposed research will also be useful in revising and enhancing the CSA design standards for containment and safety-related structures. The process of developing the research program started with an information collection and review phase. The sources of information included C-FER's previous work in the area, various recent research publications, regulatory documents and relevant design standards, and a detailed discussion with AECB staff. The second step was to outline the process of reliability evaluation, and identify the required models and parameters. Comparison between the required and available information was used to identify gaps in the state-of-the-art, and the research program was designed to fill these gaps. The program is organized in four major topics, namely: development of an approach for reliability analysis; compilation and development of the required analysis tools; application to specific problems related to design, assessment, maintenance and testing of structures; and testing and validation. It is suggested that the program should be supported by an on-going process of communication and consultation between AECB staff and industry experts. This will lend credibility to the results and facilitate their future application. (author). 1 fig

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

International Nuclear Information System (INIS)

Lydell, B.O.Y.

1997-01-01

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

Constructability and maintainability

International Nuclear Information System (INIS)

Hart, R.S.

1985-01-01

A set of principles for minimizing the construction schedule was established at the outset of the CANDU 300 programme. Consideration of these principles and other factors led to the development of the unique CANDU 300 station layout. The paper discusses the CANDU 300 station layout and construction methods. In summary, the station layout provides 360 deg. construction access to all buildings, separation of nuclear and non-nuclear systems, precise and minimal physical interfaces between buildings, accommodation of many contractors and construction activities without interference, and maximum flexibility in terms of constructional, financial and supply arrangements. The CANDU 300 further employs modularization, shop fabrication and advanced instrumentation (multiplexers, remote processors, data highways) to minimize construction time. Many of the CANDU 300 features that enhance constructability also contribute to maintainability. These include the 360 deg. access to all principal buildings, the uncluttered and spacious building layouts, the simplification of systems and the high level of modularization. The CANDU 300 has also been designed to facilitate the replacement of all key components, thereby offering an essentially unlimited station life. A prime example is a reduction in the fuel channel inlet end-fitting diameter such that the fuel channels can be shop assembled and easily replaced after the initial 40 years of operation, without an extended unit outage. Maintainability within the reactor building has been given particular attention in the CANDU 300 design; key features of other CANDU reactors (the ability to replace a heat transport system pump motor at power, for example) have been incorporated, while accessibility and maintainability of all systems and components have been enhanced. These and other aspects of maintainability are discussed. (author)

A Hierarchical Energy Efficient Reliable Transport Protocol for Wireless Sensor Networks

Directory of Open Access Journals (Sweden)

Prabhudutta Mohanty

2014-12-01

Full Text Available The two important requirements for many Wireless Senor Networks (WSNs are prolonged network lifetime and end-to-end reliability. The sensor nodes consume more energy during data transmission than the data sensing. In WSN, the redundant data increase the energy consumption, latency and reduce reliability during data transmission. Therefore, it is important to support energy efficient reliable data transport in WSNs. In this paper, we present a Hierarchical Energy Efficient Reliable Transport Protocol (HEERTP for the data transmission within the WSN. This protocol maximises the network lifetime by controlling the redundant data transmission with the co-ordination of Base Station (BS. The proposed protocol also achieves end-to-end reliability using a hop-by-hop acknowledgement scheme. We evaluate the performance of the proposed protocol through simulation. The simulation results reveal that our proposed protocol achieves better performance in terms of energy efficiency, latency and reliability than the existing protocols.

NPTool: Towards Scalability and Reliability of Business Process Management

Science.gov (United States)

Braghetto, Kelly Rosa; Ferreira, João Eduardo; Pu, Calton

Currently one important challenge in business process management is provide at the same time scalability and reliability of business process executions. This difficulty becomes more accentuated when the execution control assumes complex countless business processes. This work presents NavigationPlanTool (NPTool), a tool to control the execution of business processes. NPTool is supported by Navigation Plan Definition Language (NPDL), a language for business processes specification that uses process algebra as formal foundation. NPTool implements the NPDL language as a SQL extension. The main contribution of this paper is a description of the NPTool showing how the process algebra features combined with a relational database model can be used to provide a scalable and reliable control in the execution of business processes. The next steps of NPTool include reuse of control-flow patterns and support to data flow management.

ECLSS Reliability for Long Duration Missions Beyond Lower Earth Orbit

Science.gov (United States)

Sargusingh, Miriam J.; Nelson, Jason

2014-01-01

Reliability has been highlighted by NASA as critical to future human space exploration particularly in the area of environmental controls and life support systems. The Advanced Exploration Systems (AES) projects have been encouraged to pursue higher reliability components and systems as part of technology development plans. However, there is no consensus on what is meant by improving on reliability; nor on how to assess reliability within the AES projects. This became apparent when trying to assess reliability as one of several figures of merit for a regenerable water architecture trade study. In the Spring of 2013, the AES Water Recovery Project (WRP) hosted a series of events at the NASA Johnson Space Center (JSC) with the intended goal of establishing a common language and understanding of our reliability goals and equipping the projects with acceptable means of assessing our respective systems. This campaign included an educational series in which experts from across the agency and academia provided information on terminology, tools and techniques associated with evaluating and designing for system reliability. The campaign culminated in a workshop at JSC with members of the ECLSS and AES communities with the goal of developing a consensus on what reliability means to AES and identifying methods for assessing our low to mid-technology readiness level (TRL) technologies for reliability. This paper details the results of the workshop.

Application of support vector machines in the evaluation of reliability generation and transmission systems; Aplicacao de maquinas de vetores suporte na avaliacao da confiabilidade de sistemas de geracao e transmissao

Energy Technology Data Exchange (ETDEWEB)

Dutra, Wellington Damascena; Resende, Leonidas Chaves de [Universidade Federal de Sao Joao Del-Rei (UFSJ), MG (Brazil); Manso, Luiz Antonio da Fonseca; Silva, Armando Martins Leite da [Universidade Federal de Itajuba (UNIFEI), MG (Brazil)

2010-07-01

This paper presents a methodology for assessing the reliability indices for composite generation and transmission systems based on Support Vector Machines (SVM). The importance of SVMs is its high generalization ability. The SVMs are used to classify data into two distinct classes. These can be named positive and negative. Thus, the basic idea is to classify the system states into success or failure. For this, a pre-classification of states is achieved by performing the proposed SVM-based neural network, where the sampled states during the beginning of the non-sequential Monte Carlo simulation (MCS) are considered as input data for training and validation sets. By adopting this procedure, a large number of states are classified by a simple evaluation of the network, providing significant reductions in computational costs. The proposed methodology is applied to the IEEE Reliability Test System and to the IEEE Modified Reliability Test System. (author)

Analyzing the reliability of shuffle-exchange networks using reliability block diagrams

International Nuclear Information System (INIS)

Bistouni, Fathollah; Jahanshahi, Mohsen

2014-01-01

Supercomputers and multi-processor systems are comprised of thousands of processors that need to communicate in an efficient way. One reasonable solution would be the utilization of multistage interconnection networks (MINs), where the challenge is to analyze the reliability of such networks. One of the methods to increase the reliability and fault-tolerance of the MINs is use of various switching stages. Therefore, recently, the reliability of one of the most common MINs namely shuffle-exchange network (SEN) has been evaluated through the investigation on the impact of increasing the number of switching stage. Also, it is concluded that the reliability of SEN with one additional stage (SEN+) is better than SEN or SEN with two additional stages (SEN+2), even so, the reliability of SEN is better compared to SEN with two additional stages (SEN+2). Here we re-evaluate the reliability of these networks where the results of the terminal, broadcast, and network reliability analysis demonstrate that SEN+ and SEN+2 continuously outperform SEN and are very alike in terms of reliability. - Highlights: • The impact of increasing the number of stages on reliability of MINs is investigated. • The RBD method as an accurate method is used for the reliability analysis of MINs. • Complex series–parallel RBDs are used to determine the reliability of the MINs. • All measures of the reliability (i.e. terminal, broadcast, and network reliability) are analyzed. • All reliability equations will be calculated for different size N×N

A Bayesian least-squares support vector machine method for predicting the remaining useful life of a microwave component

Directory of Open Access Journals (Sweden)

Fuqiang Sun

2017-01-01

Full Text Available Rapid and accurate lifetime prediction of critical components in a system is important to maintaining the system’s reliable operation. To this end, many lifetime prediction methods have been developed to handle various failure-related data collected in different situations. Among these methods, machine learning and Bayesian updating are the most popular ones. In this article, a Bayesian least-squares support vector machine method that combines least-squares support vector machine with Bayesian inference is developed for predicting the remaining useful life of a microwave component. A degradation model describing the change in the component’s power gain over time is developed, and the point and interval remaining useful life estimates are obtained considering a predefined failure threshold. In our case study, the radial basis function neural network approach is also implemented for comparison purposes. The results indicate that the Bayesian least-squares support vector machine method is more precise and stable in predicting the remaining useful life of this type of components.

Reliability database development and plant performance improvement effort at Korea Hydro and Nuclear Power Co

International Nuclear Information System (INIS)

Oh, S. J.; Hwang, S. W.; Na, J. H.; Lim, H. S.

2008-01-01

Nuclear utilities in recent years have focused on improved plant performance and equipment reliability. In U.S., there is a movement toward process integration. Examples are INPO AP-913 equipment reliability program and the standard nuclear performance model developed by NEI. Synergistic effect from an integrated approach can be far greater than as compared to individual effects from each program. In Korea, PSA for all Korean NPPs (Nuclear Power Plants) has been completed. Plant performance monitoring and improvement is an important goal for KHNP (Korea Hydro and Nuclear Power Company) and a risk monitoring system called RIMS has been developed for all nuclear plants. KHNP is in the process of voluntarily implementing maintenance rule program similar to that in U.S. In the future, KHNP would like to expand the effort to equipment reliability program and to achieve highest equipment reliability and improved plant performance. For improving equipment reliability, the current trend is moving toward preventive/predictive maintenance from corrective maintenance. With the emphasis on preventive maintenance, the failure cause and operation history and environment are important. Hence, the development of accurate reliability database is necessary. Furthermore, the database should be updated regularly and maintained as a living program to reflect the current status of equipment reliability. This paper examines the development of reliability database system and its application of maintenance optimization or Risk Informed Application (RIA). (authors)

Laboratory testing of a long expansion rock bolt support for energy-absorbing applications

Directory of Open Access Journals (Sweden)

Skrzypkowski Krzysztof

2018-01-01

Full Text Available The main purpose of rock support and reinforcement in underground mining is to maintain excavations safe and open for their intended lifespan. The basic type of rock mass reinforcement method both in ore and hard coal mining is rock bolt support. Very often, existing bolt support systems are not always capable of providing a reliable controlled performance. Therefore, in recent years energy-absorbing bolts which are exposed to dynamic loading, for example from rock burst caused by high rock stresses, earthquakes, or blasting have appeared. In this article particular attention was paid to short and long expansion bolts. Quasi-static tests of expansion bolts were carried out at the laboratory test facility in simulated mining conditions, especially for the KGHM Polska Miedź S.A. mines. In the underground mines of the Legnica-Głogów Copper District (LGOM the main way to protect the room excavation is rock bolt support with a length from 1.2 m to 2.6 m. Rock bolt support longer than 2.6 m is considered as additional support of excavations and is increasingly being used to reinforce the roofs. The comparisons of energy-absorbing short and long expansion bolts with a length of 1.8m, 3.6m and 5.2m were presented. In addition, for elastic and plastic range of each bolts were determined.

Laboratory testing of a long expansion rock bolt support for energy-absorbing applications

Science.gov (United States)

Skrzypkowski, Krzysztof

2018-01-01

The main purpose of rock support and reinforcement in underground mining is to maintain excavations safe and open for their intended lifespan. The basic type of rock mass reinforcement method both in ore and hard coal mining is rock bolt support. Very often, existing bolt support systems are not always capable of providing a reliable controlled performance. Therefore, in recent years energy-absorbing bolts which are exposed to dynamic loading, for example from rock burst caused by high rock stresses, earthquakes, or blasting have appeared. In this article particular attention was paid to short and long expansion bolts. Quasi-static tests of expansion bolts were carried out at the laboratory test facility in simulated mining conditions, especially for the KGHM Polska Miedź S.A. mines. In the underground mines of the Legnica-Głogów Copper District (LGOM) the main way to protect the room excavation is rock bolt support with a length from 1.2 m to 2.6 m. Rock bolt support longer than 2.6 m is considered as additional support of excavations and is increasingly being used to reinforce the roofs. The comparisons of energy-absorbing short and long expansion bolts with a length of 1.8m, 3.6m and 5.2m were presented. In addition, for elastic and plastic range of each bolts were determined.

Standardization of Brief Inventory of Social Support Exchange Network (BISSEN) in Japan.

Science.gov (United States)

Aiba, Miyuki; Tachikawa, Hirokazu; Fukuoka, Yoshiharu; Lebowitz, Adam; Shiratori, Yuki; Doi, Nagafumi; Matsui, Yutaka

2017-07-01

This study describes the Brief Inventory of Social Support Exchange Network (BISSEN) as a standardized brief inventory measuring various aspects of social support. We confirmed the reliability and validity for function and direction of support and standardized the BISSEN. For Sample 1, a stratified random sampling method was used to select 5200 residents in Japan. We conducted mail surveys and responses were retrieved from 2274 participants (collection rate 43.7%). Participants completed a questionnaire packet that included BISSEN, suicidal ideation, depression, support seeking, and Multidimensional Scale of Perceived Social Support (MSPSS). Sample 2 surveys for test-retest reliability were conducted on 23 residents at approximately two-week intervals. Participants were asked about gender, age, and BISSEN. First, we assessed the internal consistency, test-retest reliability, construct, convergent, and concurrent validity. McDonald's omega (.73-.92) and test-retest correlations (.78-.85) demonstrated adequate internal consistency and test-retest reliability. Depression, support seeking, and MSPSS were significantly correlated with all scores of BISSEN. The non-suicidal ideation group had significantly more support compared to the suicidal ideation group. Therefore, function and direction of support in BISSEN had sufficient reliability and validity. Next, we standardized BISSEN using Z-scores and percentile rank with respect to each 12 norm groups by age and gender. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.

CERTS: Consortium for Electric Reliability Technology Solutions - Research Highlights

Energy Technology Data Exchange (ETDEWEB)

Eto, Joseph

2003-07-30

Historically, the U.S. electric power industry was vertically integrated, and utilities were responsible for system planning, operations, and reliability management. As the nation moves to a competitive market structure, these functions have been disaggregated, and no single entity is responsible for reliability management. As a result, new tools, technologies, systems, and management processes are needed to manage the reliability of the electricity grid. However, a number of simultaneous trends prevent electricity market participants from pursuing development of these reliability tools: utilities are preoccupied with restructuring their businesses, research funding has declined, and the formation of Independent System Operators (ISOs) and Regional Transmission Organizations (RTOs) to operate the grid means that control of transmission assets is separate from ownership of these assets; at the same time, business uncertainty, and changing regulatory policies have created a climate in which needed investment for transmission infrastructure and tools for reliability management has dried up. To address the resulting emerging gaps in reliability R&D, CERTS has undertaken much-needed public interest research on reliability technologies for the electricity grid. CERTS' vision is to: (1) Transform the electricity grid into an intelligent network that can sense and respond automatically to changing flows of power and emerging problems; (2) Enhance reliability management through market mechanisms, including transparency of real-time information on the status of the grid; (3) Empower customers to manage their energy use and reliability needs in response to real-time market price signals; and (4) Seamlessly integrate distributed technologies--including those for generation, storage, controls, and communications--to support the reliability needs of both the grid and individual customers.

Prefrontal Neuronal Excitability Maintains Cocaine-Associated Memory During Retrieval

Directory of Open Access Journals (Sweden)

James M. Otis

2018-06-01

Full Text Available Presentation of drug-associated cues provokes craving and drug seeking, and elimination of these associative memories would facilitate recovery from addiction. Emotionally salient memories are maintained during retrieval, as particular pharmacologic or optogenetic perturbations of memory circuits during retrieval, but not after, can induce long-lasting memory impairments. For example, in rats, inhibition of noradrenergic beta-receptors, which control intrinsic neuronal excitability, in the prelimbic medial prefrontal cortex (PL-mPFC can cause long-term memory impairments that prevent subsequent cocaine-induced reinstatement. The physiologic mechanisms that allow noradrenergic signaling to maintain drug-associated memories during retrieval, however, are unclear. Here we combine patch-clamp electrophysiology ex vivo and behavioral neuropharmacology in vivo to evaluate the mechanisms that maintain drug-associated memory during retrieval in rats. Consistent with previous studies, we find that cocaine experience increases the intrinsic excitability of pyramidal neurons in PL-mPFC. In addition, we now find that this intrinsic plasticity positively predicts the retrieval of a cocaine-induced conditioned place preference (CPP memory, suggesting that such plasticity may contribute to drug-associated memory retrieval. In further support of this, we find that pharmacological blockade of a cAMP-dependent signaling cascade, which allows noradrenergic signaling to elevate neuronal excitability, is required for memory maintenance during retrieval. Thus, inhibition of PL-mPFC neuronal excitability during memory retrieval not only leads to long-term deficits in the memory, but this memory deficit provides protection against subsequent cocaine-induced reinstatement. These data reveal that PL-mPFC intrinsic neuronal excitability maintains a cocaine-associated memory during retrieval and suggest a unique mechanism whereby drug-associated memories could be targeted

Reliability data banks

International Nuclear Information System (INIS)

Cannon, A.G.; Bendell, A.

1991-01-01

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

An Introduction To Reliability

International Nuclear Information System (INIS)

Park, Kyoung Su

1993-08-01

This book introduces reliability with definition of reliability, requirement of reliability, system of life cycle and reliability, reliability and failure rate such as summary, reliability characteristic, chance failure, failure rate which changes over time, failure mode, replacement, reliability in engineering design, reliability test over assumption of failure rate, and drawing of reliability data, prediction of system reliability, conservation of system, failure such as summary and failure relay and analysis of system safety.

A Study on the Joint Reliability Importance with Applications to the Maintenance Policy

Energy Technology Data Exchange (ETDEWEB)

Hong, Jung Sik; Kwon, Hong Je; Song, Mi Ja; Kim, Woong Kil; Yoong, Do Hwa [Seoul National Polytechnic University, Seoul (Korea, Republic of); Moon, Sin Myung; Cho, Bong Je; Moon, Jae Phil; Koo, Hoon Young; Lee, Jin Seung [Seoul National University, Seoul (Korea, Republic of)

1997-09-01

The objective of this project is to investigate the possibility of applying the Joint Reliability Importance(JRI) of two components to the establishment of system maintenance policy. Components are classified into reliability substitutes and reliability compliments. If the sign of JRI of two components is positive, they are called as reliability compliments. If the sign of JRI of two components is negative, they are called as reliability substitutes. In case of reliability compliments, one component becomes more important as the other one works and in case of reliability substitutes, one component becomes more important as the other one fails. Therefore, when the preventive maintenance is carried out, two components which are reliability substitutes should not be maintained at the same time. Also, when the corrective maintenance is carried out, we not only repair the failed components but pay attention to the functioning components which are reliability substitutes with respect to the failed components. The sign of JRI of any two components in series (parallel) system is positive (negative). Then, what is the sign of any two components in k-out-of-n:G system? This project presents an idea of characterizing the k-out-of-n:G system by calculating the JRI of two components in that system, assuming that reliability of all components are equal. In addition to the JRI of two components, JRI of two gates is introduced in this project. The algorithm to compute the JRI of two gates is presented. Bridge system is considered and the co-relation of two min cut sets is illustrated by using the cut-set representation of bridge system and calculating the JRI of two gates. 28 refs., 20 tabs., 32 figs. (author)

Strategy of Trade-Reliable Featured Product Supporting Regional Innovation Systems

Science.gov (United States)

Riskiawan, H. Y.; Purnomo, B. H.; Abdurahman, A.; Hariono, B.; Puspitasari, T. D.

2018-01-01

Pacitan, Ponorogo, and Magetan had planned the development of featured products as contained in the Medium Term Development Plan (MTDP) until 2020. The focus of development is almost similar to featured products derived from agribusiness, food processing, handycrafts, and tourism. The geographical proximity results characteristics of natural resources and social culture have similarities, including the type of featured products, constraints, problems, and opportunities for development. Given the characteristics and the support system of some featured products contained in these three regions have a lot in common and their functional interactions involving actors from across the region, it is necessary to develop cross-jurisdictional policy. The resulting strategy should be able to support the development of Regional Innovation System (RIS). The purpose of this research is 1) Determining featured product cross-regional between Pacitan regency; Ponorogo and Magetan districts in support of RIS development; and 2) Designing a featured product development strategy using supply chain management in order to drive the local economy. Based on the results of research conducted, featured products across the region that have potentiality to be developed are: processed products of “janggelan” leather products, and woven bamboo.

30 CFR 780.38 - Support facilities.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Support facilities. 780.38 Section 780.38... Support facilities. Each applicant for a surface coal mining and reclamation permit shall submit a description, plans, and drawings for each support facility to be constructed, used, or maintained within the...

30 CFR 784.30 - Support facilities.

Science.gov (United States)