WorldWideScience

Sample records for reliability improvement warranty

  1. EXTENDED WARRANTY STRATEGIES FOR ONLINE SHOPPING SUPPLY CHAIN WITH COMPETING SUPPLIERS CONSIDERING COMPONENT RELIABILITY

    Institute of Scientific and Technical Information of China (English)

    Xinghong Qin; Qiang Su; Samuel H.Huang

    2017-01-01

    This article presents the issue of extended warranty and management strategies in a three-echelon competing online shopping supply chain with price-and base warranty period-dependent demand.We employ game theory to develop decision models to explore the interactions between component suppliers and the manufacturer,as well as competition between two component suppliers.Products and extended warranty are sold by an online store,which is the leader in the Stackelberg game.Two scenarios are considered:either the manufacturer offers a prepaid extended warranty to customers or doses not.In each scenario,base warranties are assumed to be bundled with products.Our results show that when the manufacturer's repair costs change in a proper range,providing extended warranty can benefit both the manufacturer and the online store;otherwise,the manufacturer has no incentive to offer the extended warranty.Reducing repair costs,improving component reliability,or shortening the base warranty period allows the manufacturer to realize significantly better value of the extended warranty.High component reliability benefits both the manufacturer and the online store,with the manufacturer reaping more benefit.Extending the length of the base warranty adversely affects profit of the manufacturer and the value of the extended warranty.

  2. Improving the system of warranty service of trucks in foreign markets

    Directory of Open Access Journals (Sweden)

    Irina MAKAROVA

    2015-03-01

    Full Text Available The article is devoted to the practical methods development of improving one of the ways to ensure the health of trucks in the system warranty. Methodology is aimed at optimizing the processes of formation of warranty spare parts kits during the implementation of KAMAZ trucks in foreign markets. The example is given to demonstrate the importance of different factors in the formation of the warranty set for different regions. The algorithm was developed to assess the qualitative composition formed warranty package that will optimize the planning and organization of activity centers to improve operational reliability of commercial trucks. A basis for acceptance of the scientifically-proved decisions is the statistical data analysis of requests monitoring that allows organizing duly replacement of parts with expired service life, and also promotes customer servicing quality improvement and reliability of trucks by prevention of its failures.

  3. Some reliability issues for incomplete two-dimensional warranty claims data

    International Nuclear Information System (INIS)

    Kumar Gupta, Sanjib; De, Soumen; Chatterjee, Aditya

    2017-01-01

    Bivariate reliability and vector bivariate hazard rate or hazard gradient functions are expected to have a role for meaningful assessment of the field performance for items under two-dimensional warranty coverage. In this paper a usage rate based simple class of bivariate reliability function is proposed and various bivariate reliability characteristics are studied for warranty claims data. The utilities of such study are explored with the help of a real life synthetic data. - Highlights: • Independence between age and usage rate is established. • Conditional reliability and hazard gradient along age and usage are determined. • The change point of the hazard gradients is estimated. • The concepts of layered renewal process and NHPP are introduced. • Expected number of renewals and failures at different age-usage cut-offs are obtained.

  4. Improving machinery reliability

    CERN Document Server

    Bloch, Heinz P

    1998-01-01

    This totally revised, updated and expanded edition provides proven techniques and procedures that extend machinery life, reduce maintenance costs, and achieve optimum machinery reliability. This essential text clearly describes the reliability improvement and failure avoidance steps practiced by best-of-class process plants in the U.S. and Europe.

  5. Improving Power Converter Reliability

    DEFF Research Database (Denmark)

    Ghimire, Pramod; de Vega, Angel Ruiz; Beczkowski, Szymon

    2014-01-01

    of a high-power IGBT module during converter operation, which may play a vital role in improving the reliability of the power converters. The measured voltage is used to estimate the module average junction temperature of the high and low-voltage side of a half-bridge IGBT separately in every fundamental......The real-time junction temperature monitoring of a high-power insulated-gate bipolar transistor (IGBT) module is important to increase the overall reliability of power converters for industrial applications. This article proposes a new method to measure the on-state collector?emitter voltage...... is measured in a wind power converter at a low fundamental frequency. To illustrate more, the test method as well as the performance of the measurement circuit are also presented. This measurement is also useful to indicate failure mechanisms such as bond wire lift-off and solder layer degradation...

  6. Warranty forecasting from incomplete two-dimensional warranty data

    International Nuclear Information System (INIS)

    Gupta, Sanjib Kumar; De, Soumen; Chatterjee, Aditya

    2014-01-01

    Warranty modelling with incomplete data is a major issue in reliability analysis. The incomplete failure region characterized by warranty field data may be classified into several domains representing failures from manufacturing/assembly defects, usage or fatigue. In the present paper a data driven approach has been suggested to demark the regions optimally through estimation of the change point in a hazard function. In the perspective of bivariate warranty analysis, as relevant in automobiles, we have assumed the lifetime distribution to be a mixture of distributions corresponding to the burn-in period and the useful life period. The proportions of observations in different regions demarketed by the warranty policy in the bivariate plane have been estimated by considering mileage along with age. The estimation scheme has been verified and validated through extensive simulation studies. The utilities of the results have been demonstrated by addressing several issues through a real life synthetic warranty data set from a large automobile company. - Highlights: • Detailed responses to all comments of the reviewers are attached in a separate file. Almost all of the suggestions of the reviewers are incorporated in the revised manuscript. • Some recent works of different authors as mentioned by the reviewers have been included in the revised manuscript. • The term change point with reference to the transition from $DFR$ to $CFR$ part of the bath-tub curve has been elaborated. • A sample of real life data has been given in the revised manuscript in Table $4$, by following the suggestion of reviewer 2. • The findings have been summarised in a better way in the conclusion part. In this portion we have emphasized on the take away of our work. Scopes for future work have also been mentioned

  7. Warranty menu design for a two-dimensional warranty

    International Nuclear Information System (INIS)

    Ye, Zhi-Sheng; Murthy, D.N. Pra

    2016-01-01

    Fierce competitions in the commercial product market have forced manufacturers to provide customer-friendly warranties with a view to achieving higher customer satisfaction and increasing the market share. This study proposes a strategy that offers customers a two-dimensional warranty menu with a number of warranty choices, called a flexible warranty policy. We investigate the design of a flexible two-dimensional warranty policy that contains a number of rectangular regions. This warranty policy is obtained by dividing customers into several groups according to their use rates and providing each group a germane warranty region. Consumers choose a favorable one from the menu according to their usage behaviors. Evidently, this flexible warranty policy is attractive to users of different usage behaviors, and thus, it gives the manufacturer a good position in advertising the product. When consumers are unaware about their use rates upon purchase, we consider a fixed two-dimensional warranty policy with a stair-case warranty region and show that it is equivalent to the flexible policy. Such an equivalence reveals the inherent relationship between the rectangular warranty policy, the L-shape warranty policy, the step-stair warranty policy and the iso-probability of failure warranty policy that were extensively discussed in the literature. - Highlights: • We design a two-dimensional warranty menu with a number of warranty choices. • Consumers can choose a favorable one from the menu as per their usage behavior. • We further consider a fixed 2D warranty policy with a stair-case warranty region. • We show the equivalence of the two warranty policies.

  8. Steam generator reliability improvement project

    International Nuclear Information System (INIS)

    Blomgren, J.C.; Green, S.J.

    1987-01-01

    Upon successful completion of its research and development technology transfer program, the Electric Power Research Institute's Steam Generator Owners Group (SGOG II) will disband in December 1986 and be replaced in January 1987 by a successor project, the Steam Generator Reliability Project (SGRP). The new project, funded in the EPRI base program, will continue the emphasis on reliability and life extension that was carried forward by SGOG II. The objectives of SGOG II have been met. Causes and remedies have been identified for tubing corrosion problems, such as stress corrosion cracking and pitting, and steam generator technology has been improved in areas such as tube wear prediction and nondestructive evaluation (NDE). These actions have led to improved reliability of steam generators. Now the owners want to continue with a centrally managed program that builds on what has been learned. The goal is to continue to improve steam generator reliability and solve small problems before they become large problems

  9. Steam generator reliability improvement project

    International Nuclear Information System (INIS)

    Blomgren, J.C.; Green, S.J.

    1987-01-01

    Upon successful completion of its research and development technology transfer program, the Electric Power Research Institute's (EPRI's) Steam Generator Owners Group (SGOG II) will disband in December 1986, and be replaced in January 1987, by a successor project, the Steam Generator Reliability Project (SGRP). The new project, funded in the EPRI base program, will continue to emphasize reliability and life extension, which were carried forward by SGOG II. The objectives of SGOG II have been met. Causes and remedies have been identified for tubing corrosion problems such as stress corrosion cracking and pitting, and steam generator technology has been improved in areas such as tube wear prediction and nondestructive evaluation. These actions have led to improved reliability of steam generators. Now the owners want to continue with a centrally managed program that builds on what has been learned. The goal is to continue to improve steam generator reliability and to solve small problems before they become large problems

  10. Teaming up to improve reliability

    International Nuclear Information System (INIS)

    Malone, E.A.; Ayres, D.J.; Lear, R.C. van

    1989-01-01

    Responding to increasingly stringent regulatory requirements, Babcock and Wilcox has teamed up with three specialist companies to provide services for nuclear utilities aiming to improve the performance of their valves and actuators. The services, which are outlined here, include inspection, repair, overhaul and valve and actuator reliability programmes. (author)

  11. PWR system reliability improvement activities

    International Nuclear Information System (INIS)

    Yoshikawa, Yuichiro

    1985-01-01

    In Japan lacking in energy resources, it is our basic energy policy to accelerate the development program of nuclear power, thereby reducing our dependence. As referred to in the foregoing, every effort has been exerted on our part to improve the PWR system reliability by dint of the so-called 'HOMEMADE' TQC activities, which is our brain-child as a result of applying to the energy industry the quality control philosophy developed in the field of manufacturing industry

  12. The Effectiveness of Warranties in the Solar Photovoltaic and Automobile Industries

    Science.gov (United States)

    Formica, Tyler J.

    A warranty is an agreement outlined by a manufacturer to a customer that defines performance requirements for a product or service. Although long warranty periods are a useful marketing tool, in 2011 the warranty claims expense was 2.6% of total sales for computer original equipment manufacturers (OEMs) and is over 2% of total sales in many other industries today. Solar PV systems offer inverters with 5-15 year warranties and PV modules with 25-year performance warranties. This is problematic for the return on investment (ROI) of solar PV systems when the modules are still productive and covered under warranty but inverter failures occur due to degradation of electronic components after their warranty has expired. Out-of-warranty inverter failures during the lifetime of solar panels decrease the ROI of solar PV systems significantly and can cause the annual ROI to actually be negative 15-25 years into the lifetime of the system. This thesis analyzes the factors that contribute to designing an optimal warranty period and the relationship between reliability and warranty periods using General Motors (GM) and the solar PV industry as case studies. A return on investment of a solar photovoltaic system is also conducted and the effect of reliability, changing tax credit structures, and failure areas of solar PV systems are analyzed.

  13. Optimal replacement policy of products with repair-cost threshold after the extended warranty

    Institute of Scientific and Technical Information of China (English)

    Lijun Shang; Zhiqiang Cai

    2017-01-01

    The reliability of the product sold under a warranty is usually maintained by the manufacturer during the warranty period. After the expiry of the warranty, however, the consumer confronts a problem about how to maintain the reliability of the product. This paper proposes, from the consumer's perspective, a replace-ment policy after the extended warranty, under the assumption that the product is sold under the renewable free replacement warranty (RFRW) policy in which the replacement is dependent on the repair-cost threshold. The proposed replacement policy is the replacement after the extended warranty is performed by the consumer based on the repair-cost threshold or preventive replacement (PR) age, which are decision variables. The expected cost rate model is derived from the consumer's perspective. The existence and uniqueness of the optimal solution that minimizes the expected cost rate per unit time are offered. Finally, a numeri-cal example is presented to exemplify the proposed model.

  14. Warranties for Weapons: Theory and Initial Assessment.

    Science.gov (United States)

    1987-04-01

    do little more than compare interim contractor support with organic depot repair. Few recognize that risk and uncertainty are the major environmental ...significantly enhance the reliability of the TACAN. However, government fulfillment of its contractual obligations or lack thereof caused serious impacts to...First, there are two potential award fees, which we will not consider as part of the warranty. One was set for January of 1983 (when WEC received

  15. Developing methods for establishing improved plant reliability

    International Nuclear Information System (INIS)

    Zebroski, E.L.; Lapides, M.E.; Johnson, L.

    1976-01-01

    The current average capacity factor for nuclear electric generating facilities is approximately 60 percent, virtually the same as that for large, modern fossil-fired units. There is a clear cost advantage for nuclear electrical generation in comparison to coal-fired units at a common performance level. Because of the accelerated increase in capital and fuel costs of coal-fired units, the nuclear units will usually exhibit a cost advantage even when operating at lower capacity factor values. The incentives for improvement follow from the utility objectives to provide electricity at the most economical rates possible and are reflected in reduced system fuel costs and capital requirements. These objectives require maximizing the productivity of existing or planned investments in nuclear generation. The requirements are to: (1) achieve and sustain the highest capacity factor consistent with each utility's electric transmission system configuration and demand; (2) accelerate the rate of attainment of operational ''maturity'' of new generation; and (3) avoid low-probability but large-consequence forced-outage events. Nuclear unit productivity improvement involves utilities, regulatory agencies and industrial and government research and development organizations; the efforts appropriate to each organization were identified in a previous study. Since no foreseeable set of warranties begins to cover the consequential costs of low performance, the greatest incentive for improvement rests with each individual utility. The paper addresses the methodology and information sources for productivity actions by utilities during unit procurement and design phases

  16. Auto warranty and driving patterns

    International Nuclear Information System (INIS)

    Anastasiadis, Simon; Anderson, Boyd; Chukova, Stefanka

    2013-01-01

    Automobile warranty coverage is typically limited by age as well as mileage. However, the age is known for all sold vehicles at all times, but mileage is only observed for a vehicle with a claim and only at the time of the claim. We study the relationship between the expected number/cost of warranty claims and the driving patterns. Within a nonparametric framework, we account for the rate of mileage accumulation and propose a measure for the variability of this rate over a vehicle's observable life. We illustrate the ideas with real warranty data and comment on the relationship between the expected number/cost of warranty claims and the driving patterns using results adjusted/unadjusted for withdrawals from the warranty coverage due to mileage accumulation

  17. The protection of warranties and representations

    International Nuclear Information System (INIS)

    Spence, C.D.; Thusoo, N.

    1999-01-01

    Most acquisition contracts within the oil and gas industry consist of representations and warranties. The legal distinction between representations and warranties was explained as follows: a representation is a statement of fact made by the representor before making the contract, but a warranty is a statement of fact which forms part of the terms of the contract. The paper outlines the nature of a representation or warranty and explains why certain warranties are not given. The protection offered by representations and warranties in breach of contract cases is also explained. Suggestions are offered for increasing protection by representations and warranties. 22 refs

  18. Improved reliability of power modules

    DEFF Research Database (Denmark)

    Baker, Nick; Liserre, Marco; Dupont, Laurent

    2014-01-01

    Power electronic systems play an increasingly important role in providing high-efficiency power conversion for adjustable-speed drives, power-quality correction, renewable-energy systems, energy-storage systems, and electric vehicles. However, they are often presented with demanding operating...... environments that challenge the reliability aspects of power electronic techniques. For example, increasingly thermally stressful environments are seen in applications such as electric vehicles, where ambient temperatures under the hood exceed 150 °C, while some wind turbine applications can place large...

  19. 40 CFR 85.2109 - Inclusion of warranty provisions in owners' manuals and warranty booklets.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 18 2010-07-01 2010-07-01 false Inclusion of warranty provisions in owners' manuals and warranty booklets. 85.2109 Section 85.2109 Protection of Environment ENVIRONMENTAL....2109 Inclusion of warranty provisions in owners' manuals and warranty booklets. (a) A manufacturer...

  20. Long-term warranties on highway projects.

    Science.gov (United States)

    2008-09-01

    This report documents the state of the art and practice of warranty contracting in the United States. Background information, key elements, benefits and concerns, and lesson learned in other states regarding warranty contracting are presented in the ...

  1. Reliability-How to Quantify and Improve?

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 5; Issue 5. Reliability - How to Quantify and Improve? - Improving the Health of Products. N K Srinivasan. General Article Volume 5 Issue 5 May 2000 pp 55-63. Fulltext. Click here to view fulltext PDF. Permanent link:

  2. Improving Reliability of a Residency Interview Process

    Science.gov (United States)

    Serres, Michelle L.; Gundrum, Todd E.

    2013-01-01

    Objective. To improve the reliability and discrimination of a pharmacy resident interview evaluation form, and thereby improve the reliability of the interview process. Methods. In phase 1 of the study, authors used a Many-Facet Rasch Measurement model to optimize an existing evaluation form for reliability and discrimination. In phase 2, interviewer pairs used the modified evaluation form within 4 separate interview stations. In phase 3, 8 interviewers individually-evaluated each candidate in one-on-one interviews. Results. In phase 1, the evaluation form had a reliability of 0.98 with person separation of 6.56; reproducibly, the form separated applicants into 6 distinct groups. Using that form in phase 2 and 3, our largest variation source was candidates, while content specificity was the next largest variation source. The phase 2 g-coefficient was 0.787, while confirmatory phase 3 was 0.922. Process reliability improved with more stations despite fewer interviewers per station—impact of content specificity was greatly reduced with more interview stations. Conclusion. A more reliable, discriminating evaluation form was developed to evaluate candidates during resident interviews, and a process was designed that reduced the impact from content specificity. PMID:24159209

  3. Improving reliability of a residency interview process.

    Science.gov (United States)

    Peeters, Michael J; Serres, Michelle L; Gundrum, Todd E

    2013-10-14

    To improve the reliability and discrimination of a pharmacy resident interview evaluation form, and thereby improve the reliability of the interview process. In phase 1 of the study, authors used a Many-Facet Rasch Measurement model to optimize an existing evaluation form for reliability and discrimination. In phase 2, interviewer pairs used the modified evaluation form within 4 separate interview stations. In phase 3, 8 interviewers individually-evaluated each candidate in one-on-one interviews. In phase 1, the evaluation form had a reliability of 0.98 with person separation of 6.56; reproducibly, the form separated applicants into 6 distinct groups. Using that form in phase 2 and 3, our largest variation source was candidates, while content specificity was the next largest variation source. The phase 2 g-coefficient was 0.787, while confirmatory phase 3 was 0.922. Process reliability improved with more stations despite fewer interviewers per station-impact of content specificity was greatly reduced with more interview stations. A more reliable, discriminating evaluation form was developed to evaluate candidates during resident interviews, and a process was designed that reduced the impact from content specificity.

  4. Improving the safety and reliability of Monju

    International Nuclear Information System (INIS)

    Itou, Kazumoto; Maeda, Hiroshi; Moriyama, Masatoshi

    1998-01-01

    Comprehensive safety review has been performed at Monju to determine why the Monju secondary sodium leakage accident occurred. We investigated how to improve the situation based on the results of the safety review. The safety review focused on five aspects of whether the facilities for dealing with the sodium leakage accident were adequate: the reliability of the detection method, the reliability of the method for preventing the spread of the sodium leakage accident, whether the documented operating procedures are adequate, whether the quality assurance system, program, and actions were properly performed and so on. As a result, we established for Monju a better method of dealing with sodium leakage accidents, rapid detection of sodium leakage, improvement of sodium drain facilities, and way to reduce damage to Monju systems after an accident. We also improve the operation procedures and quality assurance actions to increase the safety and reliability of Monju. (author)

  5. Heroic Reliability Improvement in Manned Space Systems

    Science.gov (United States)

    Jones, Harry W.

    2017-01-01

    System reliability can be significantly improved by a strong continued effort to identify and remove all the causes of actual failures. Newly designed systems often have unexpected high failure rates which can be reduced by successive design improvements until the final operational system has an acceptable failure rate. There are many causes of failures and many ways to remove them. New systems may have poor specifications, design errors, or mistaken operations concepts. Correcting unexpected problems as they occur can produce large early gains in reliability. Improved technology in materials, components, and design approaches can increase reliability. The reliability growth is achieved by repeatedly operating the system until it fails, identifying the failure cause, and fixing the problem. The failure rate reduction that can be obtained depends on the number and the failure rates of the correctable failures. Under the strong assumption that the failure causes can be removed, the decline in overall failure rate can be predicted. If a failure occurs at the rate of lambda per unit time, the expected time before the failure occurs and can be corrected is 1/lambda, the Mean Time Before Failure (MTBF). Finding and fixing a less frequent failure with the rate of lambda/2 per unit time requires twice as long, time of 1/(2 lambda). Cutting the failure rate in half requires doubling the test and redesign time and finding and eliminating the failure causes.Reducing the failure rate significantly requires a heroic reliability improvement effort.

  6. 48 CFR 46.709 - Warranties of commercial items.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Warranties of commercial... CONTRACT MANAGEMENT QUALITY ASSURANCE Warranties 46.709 Warranties of commercial items. The contracting officer should take advantage of commercial warranties, including extended warranties, where appropriate...

  7. Improvement of the reliability on nondestructive inspection

    International Nuclear Information System (INIS)

    Song, Sung Jin; Kim, Young H.; Lee, Hyang Beom; Shin, Young Kil; Jung, Hyun Jo; Park, Ik Keun; Park, Eun Soo

    2002-03-01

    Retaining reliabilities of nondestructive testing is essential for the life-time maintenance of Nuclear Power Plant. The nondestructive testing methods which are frequently used in the Nuclear Power Plant are eddy current testing for the inspection of steam generator tubes and ultrasonic testing for the inspection of weldments. In order to improve reliabilities of ultrasonic testing and eddy current testing, the subjects carried out in this study are as follows : development of BEM analysis technique for ECT of SG tube, development of neural network technique for the intelligent analysis of ECT flaw signals of SG tubes, development of RFECT technology for the inspection of SG tube, FEM analysis of ultrasonic scattering field, evaluation of statistical reliability of PD-RR test of ultrasonic testing and development of multi-Gaussian beam modeling technique to predict accurate signal of signal beam ultrasonic testing with the efficiency in calculation time

  8. Improvement of the reliability on nondestructive inspection

    Energy Technology Data Exchange (ETDEWEB)

    Song, Sung Jin; Kim, Young H. [Sungkyunkwan Univ., Suwon (Korea, Republic of); Lee, Hyang Beom [Soongsil Univ., Seoul (Korea, Republic of); Shin, Young Kil [Kunsan National Univ., Gunsan (Korea, Republic of); Jung, Hyun Jo [Wonkwang Univ., Iksan (Korea, Republic of); Park, Ik Keun; Park, Eun Soo [Seoul Nationl Univ., Seoul (Korea, Republic of)

    2002-03-15

    Retaining reliabilities of nondestructive testing is essential for the life-time maintenance of Nuclear Power Plant. The nondestructive testing methods which are frequently used in the Nuclear Power Plant are eddy current testing for the inspection of steam generator tubes and ultrasonic testing for the inspection of weldments. In order to improve reliabilities of ultrasonic testing and eddy current testing, the subjects carried out in this study are as follows : development of BEM analysis technique for ECT of SG tube, development of neural network technique for the intelligent analysis of ECT flaw signals of SG tubes, development of RFECT technology for the inspection of SG tube, FEM analysis of ultrasonic scattering field, evaluation of statistical reliability of PD-RR test of ultrasonic testing and development of multi-Gaussian beam modeling technique to predict accurate signal of signal beam ultrasonic testing with the efficiency in calculation time.

  9. Warranty optimisation based on the prediction of costs to the manufacturer using neural network model and Monte Carlo simulation

    Science.gov (United States)

    Stamenkovic, Dragan D.; Popovic, Vladimir M.

    2015-02-01

    Warranty is a powerful marketing tool, but it always involves additional costs to the manufacturer. In order to reduce these costs and make use of warranty's marketing potential, the manufacturer needs to master the techniques for warranty cost prediction according to the reliability characteristics of the product. In this paper a combination free replacement and pro rata warranty policy is analysed as warranty model for one type of light bulbs. Since operating conditions have a great impact on product reliability, they need to be considered in such analysis. A neural network model is used to predict light bulb reliability characteristics based on the data from the tests of light bulbs in various operating conditions. Compared with a linear regression model used in the literature for similar tasks, the neural network model proved to be a more accurate method for such prediction. Reliability parameters obtained in this way are later used in Monte Carlo simulation for the prediction of times to failure needed for warranty cost calculation. The results of the analysis make possible for the manufacturer to choose the optimal warranty policy based on expected product operating conditions. In such a way, the manufacturer can lower the costs and increase the profit.

  10. Long term warranty and after sales service concept, policies and cost models

    CERN Document Server

    Rahman, Anisur

    2015-01-01

    This volume presents concepts, policies and cost models for various long-term warranty and maintenance contracts. It offers several numerical examples for estimating costs to both the manufacturer and consumer. Long-term warranties and maintenance contracts are becoming increasingly popular, as these types of aftersales services provide assurance to consumers that they can enjoy long, reliable service, and protect them from defects and the potentially high costs of repairs. Studying long-term warranty and service contracts is important to manufacturers and consumers alike, as offering long-term warranty and maintenance contracts produce additional costs for manufacturers / service providers over the product’s service life. These costs must be factored into the price, or the manufacturer / dealer will incur losses instead of making a profit. On the other hand, the buyer / consumer needs to weigh the cost of maintaining it over its service life and to decide whether or not these policies are worth purchasing....

  11. 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)

  12. SLAC modulator system improvements and reliability results

    International Nuclear Information System (INIS)

    Donaldson, A.R.

    1998-06-01

    In 1995, an improvement project was completed on the 244 klystron modulators in the linear accelerator. The modulator system has been previously described. This article offers project details and their resulting effect on modulator and component reliability. Prior to the project, the authors had collected four operating cycles (1991 through 1995) of MTTF data. In this discussion, the '91 data will be excluded since the modulators operated at 60 Hz. The five periods following the '91 run were reviewed due to the common repetition rate at 120 Hz

  13. Improvement of reliability of heater and condenser

    International Nuclear Information System (INIS)

    Yamagishi, Hiroki

    1988-01-01

    Recently, the diversification of the operation modes of power plants has advanced as well as daily start and stop and weekly start and stop operations, as the result, the needs for the reliability improvement of various heat exchangers around steam turbines heighten. In newly constructed plants, the design to meet this demand is carried out, but also in existing platns, the application of the latest technology is investigated. As for the reliability of condensers, aluminum brass cooling tubes have been used by doing the optimal maintenance and taking the measures against deposit attack. In the case of requiring high reliability, the examples of adopting titanium cooling tubes increased. The technology of titanium tube condensers, completely assembled condensers, the replacement of existing brass tubes with titanium tubes and so on are discussed. In the case of feed heaters, the deterioration phenomena due to the lapse of long years, such as the attack of steel tube inlet, the drain attack on the external surfaces of steel tubes, the ammonia attack of aluminum brass tubes and the adhesion of scale to heaters, are explained, and the countermeasures are shown. (Kako, I.)

  14. Statistical analysis of field data for aircraft warranties

    Science.gov (United States)

    Lakey, Mary J.

    Air Force and Navy maintenance data collection systems were researched to determine their scientific applicability to the warranty process. New and unique algorithms were developed to extract failure distributions which were then used to characterize how selected families of equipment typically fails. Families of similar equipment were identified in terms of function, technology and failure patterns. Statistical analyses and applications such as goodness-of-fit test, maximum likelihood estimation and derivation of confidence intervals for the probability density function parameters were applied to characterize the distributions and their failure patterns. Statistical and reliability theory, with relevance to equipment design and operational failures were also determining factors in characterizing the failure patterns of the equipment families. Inferences about the families with relevance to warranty needs were then made.

  15. 40 CFR 204.58-1 - Warranty.

    Science.gov (United States)

    2010-07-01

    ... regulations. This warranty is not limited to any particular part, component, or system of the air compressor. Defects in the design, assembly, or in any part, component, or system of the compressor which, at the time... by this warranty for the life of the air compressor. (b) [Reserved] (Secs. 6 and 13, Noise Control...

  16. Lessons learned : pavement marking warranty contract.

    Science.gov (United States)

    2013-12-01

    In 2012, UDOT implemented a performance-based warranty on a portion of an I-15 pavement marking : project. The awarded contract requested a contractor warranty on the implemented markings for a total : duration of six years. This is the first time th...

  17. On the Limitation of Warranty Duration.

    OpenAIRE

    Emons, Winand

    1989-01-01

    This paper analyzes the frequently-observed phenomenon that firms offer product warranties that are of much shorter duration than the life expectancy of these products. It is shown that competitive equilibria may entail limitation of warranty duration if firms face adverse selection problems with respect to different consumers. Copyright 1989 by Blackwell Publishing Ltd.

  18. 40 CFR 205.58-1 - Warranty.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Warranty. 205.58-1 Section 205.58-1 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) NOISE ABATEMENT PROGRAMS TRANSPORTATION EQUIPMENT NOISE EMISSION CONTROLS Medium and Heavy Trucks § 205.58-1 Warranty. (a) The vehicle manufacturer...

  19. Advanced solutions for operational reliability improvements

    Energy Technology Data Exchange (ETDEWEB)

    Holmberg, K [VTT Manufacturing Technology, Espoo (Finland)

    1998-12-31

    A great number of new technical tools are today developed for improved operational reliability of machines and industrial equipment. Examples of such techniques and tools recently developed at the Technical Research Centre of Finland (VTT) are: metallographic approach for steam-piping lifetime estimation, an expert system AURORA for corrosion prediction and material selection, an automatic image-processing-based on-line wear particle analysis system, microsensors for condition monitoring, a condition monitoring and expert system, CEPDIA, for the diagnosis of centrifugal pumps, a machine tool analysis and diagnostic expert system, non-leakage magnetic fluid seals with extended lifetime and diamond-like surface coatings on components with decreased friction and wear properties. A hyperbook-supported holistic approach to problem solving in maintenance and reliability engineering has been developed to help the user achieve a holistic understanding of the problem and its relationships, to navigate among the several technical tools and methods available, and to find those suitable for his application. (orig.)

  20. Advanced solutions for operational reliability improvements

    Energy Technology Data Exchange (ETDEWEB)

    Holmberg, K. [VTT Manufacturing Technology, Espoo (Finland)

    1997-12-31

    A great number of new technical tools are today developed for improved operational reliability of machines and industrial equipment. Examples of such techniques and tools recently developed at the Technical Research Centre of Finland (VTT) are: metallographic approach for steam-piping lifetime estimation, an expert system AURORA for corrosion prediction and material selection, an automatic image-processing-based on-line wear particle analysis system, microsensors for condition monitoring, a condition monitoring and expert system, CEPDIA, for the diagnosis of centrifugal pumps, a machine tool analysis and diagnostic expert system, non-leakage magnetic fluid seals with extended lifetime and diamond-like surface coatings on components with decreased friction and wear properties. A hyperbook-supported holistic approach to problem solving in maintenance and reliability engineering has been developed to help the user achieve a holistic understanding of the problem and its relationships, to navigate among the several technical tools and methods available, and to find those suitable for his application. (orig.)

  1. 48 CFR 46.706 - Warranty terms and conditions.

    Science.gov (United States)

    2010-10-01

    ... CONTRACT MANAGEMENT QUALITY ASSURANCE Warranties 46.706 Warranty terms and conditions. (a) To facilitate... are included in a contract (except contracts for commercial items), all implied warranties of... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Warranty terms and...

  2. 48 CFR 1246.706 - Warranty terms and conditions.

    Science.gov (United States)

    2010-10-01

    ... CONTRACT MANAGEMENT QUALITY ASSURANCE Warranties 1246.706 Warranty terms and conditions. (a) When... warranty as is normally provided by the manufacturer or supplier, in accordance with (FAR) 48 CFR 46.703(d... warranty in light of the technical risk, contractor financial risk, or other program uncertainties. (6...

  3. Warranty claim analysis considering human factors

    International Nuclear Information System (INIS)

    Wu Shaomin

    2011-01-01

    Warranty claims are not always due to product failures. They can also be caused by two types of human factors. On the one hand, consumers might claim warranty due to misuse and/or failures caused by various human factors. Such claims might account for more than 10% of all reported claims. On the other hand, consumers might not be bothered to claim warranty for failed items that are still under warranty, or they may claim warranty after they have experienced several intermittent failures. These two types of human factors can affect warranty claim costs. However, research in this area has received rather little attention. In this paper, we propose three models to estimate the expected warranty cost when the two types of human factors are included. We consider two types of failures: intermittent and fatal failures, which might result in different claim patterns. Consumers might report claims after a fatal failure has occurred, and upon intermittent failures they might report claims after a number of failures have occurred. Numerical examples are given to validate the results derived.

  4. Research on Probability for Failures in VW Cars During Warranty and Post-Warranty Periods

    Directory of Open Access Journals (Sweden)

    Dainius Luneckas

    2014-12-01

    Full Text Available The present paper examines the distribution of failures in „Volkswagen“ car during warranty and post-warranty periods. A statistical mathematical model has been developed upon collecting distribution data on car failures. Considering mileage rates, probabilities for a failure in the systems, including suspension and transmission, cooling, electrical, etc., have been determined during warranty and expiration periods. The obtained results of the conducted research have been compared. The reached conclusions have been formulated and summarized.

  5. 16 CFR 700.3 - Written warranty.

    Science.gov (United States)

    2010-01-01

    ... will not construe the Act to impede information disclosure in product advertising or labeling. 1 A... the consumer nor brought to the consumer's attention in connection with the sale. Such warranties are...

  6. 40 CFR 85.1409 - Warranty.

    Science.gov (United States)

    2010-07-01

    ... POLLUTION FROM MOBILE SOURCES Urban Bus Rebuild Requirements § 85.1409 Warranty. (a) As a condition of... equipment will not cause an urban bus engine to exceed the emission requirements of this subpart and the...

  7. Basic Study on Term of Warranty Liability for Miscellaneous Work

    Science.gov (United States)

    Park, Junmo; Seo, Deokseok

    2017-10-01

    In Korea, defect lawsuits for apartment buildings, the most common housing style, are becoming a social issue. Among various issues in defect lawsuits, warranty of liability is very important. This is because the business entities are responsible for assuring the maintenance of the defects during this period, and at the same time, the residents can request fair compensation for the defects. However, provisions on the term of warranty of liability provided in the current Housing Act were made 40 years ago when the social basis were weak. Thus, it does not have any rational foundation. In order to improve these problems, basic research on the warranty of liability by major types of apartments is needed. In this study, the defect cases for miscellaneous works of apartments were examined and analyzed. Miscellaneous work consists of ondol work, kitchenware work, indoor and outdoor equipment work, and metallic work. Among them, kitchenware work and metallic work showed a lot of defects. On the other hand, warranty of liability covers up to 10 years in total. The defect occurrence for the entire miscellaneous work showed a tendency to concentrate in the first and the second year. It is the third year that the total defects reach 95%, and the fourth year that exceeds 99%. The ondol work, indoor and outdoor equipment work and metallic work had this tendency. On the other hand, for kitchenware work, it is the third year that the defect occurrence reaches 99%, and it implies that the defect tends to occur more quickly than in other detailed works.

  8. Pricing and Warranty Level Decisions for New and Remanufactured Short Life-Cycle Products

    Directory of Open Access Journals (Sweden)

    Gan Shu San

    2017-06-01

    Full Text Available Remanufacturing has become more prominent as a recovery process to mitigate the massive disposal of short life-cycle product at its end-of-use. However, remanufactured product is often perceived to be inferior to new product, and it has lower value in consumer’s willingness to pay. To increase the perceived quality of the remanufactured product, manufacturer offers a warranty, since one of the three roles possessed in warranty is being a signal to product reliability. This paper studies the pricing decisions and warranty level decision for new and remanufactured products in a closed-loop supply chain consists of a manufacturer and a retailer. The optimization modeling is performed under Stackelberg game with manufacturer as the leader. We found that higher expansion effectiveness coefficient would increase the supply chain profit. Also, there is an interval of demand’s speed of change, where the total profit would be at its highest. The optimum warranty level can be achieved regardless the initial warranty level set at the beginning of retailer’s optimization. Furthermore, the remanufactured product’s wholesale and retail prices are influenced by the expansion effectiveness coefficient.

  9. 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.

  10. software reliability: failures, consequences and improvement

    African Journals Online (AJOL)

    BARTH EKWUEME

    2009-07-16

    Jul 16, 2009 ... function of time, but it is believed that some modeling technique for software reliability is reaching propensity, by ..... February 25, 1991 during the Gulf war, the chopping ... Let us consider a few key concepts that apply to both.

  11. Improvement of standards on functional reliability of electric power systems

    International Nuclear Information System (INIS)

    Barinov, V.A.; Volkov, G.A.; Kalita, V.V.; Kogan, F.L.; Makarov, S.F.; Manevich, A.S.; Mogirev, V.V.; Sin'chugov, F.I.; Skopintsev, V.A.; Khvoshchinskaya, Z.G.

    1993-01-01

    Analysis of the most principal aspects of the existing standards and requirements on assuring safety and stability of electric power systems (EPS) and effective (reliable and economical) power supply of consumers is given. The reliability is determined as ability to accomplish the assigned functions. Basic recommendations on improving the standards regulating the safety and reliability of the NPP functioning are formulated

  12. 16 CFR 700.6 - Designation of warranties.

    Science.gov (United States)

    2010-01-01

    ... the duration of an implied or written warranty (or service contract) applicable to the product... duration. However, where the duration of a full warranty is defined solely in terms of first purchaser...

  13. Enhance pump reliability through improved inservice testing

    International Nuclear Information System (INIS)

    Healy, J.J.

    1990-01-01

    EPRI has undertaken a study to assess the effectiveness of existing testing programs to accurately monitor and predict performance changes before either pump performance degrades or an actual failure occurs. Anticipated changes in inservice testing techniques are directed towards enhancing the validity of test data, ensuring its repeatability, and avoiding deterioration of the pump assembly. There is a new-found interest in test programs of all types that has occurred, in part, because of an increase in reported pump degradation and pump failure. Inservice testing of pumps, which has long been a basis for assuring operability, has apparently produced an opposite effect; namely, the appearance of a reduction in reliability

  14. 29 CFR 215.7 - The Special Warranty.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 2 2010-07-01 2010-07-01 false The Special Warranty. 215.7 Section 215.7 Labor Regulations Relating to Labor OFFICE OF LABOR-MANAGEMENT STANDARDS, DEPARTMENT OF LABOR GUIDELINES, SECTION 5333(b), FEDERAL TRANSIT LAW § 215.7 The Special Warranty. (a) The Special Warranty mentioned in paragraph (b)(2...

  15. After-sales service of engineering industrial assets a reference framework for warranty management

    CERN Document Server

    González-Prida Díaz, Vicente

    2014-01-01

    This book explores the practical implementation of an advanced after-sales management framework devoted to warranty management. The framework is intended for companies producing either standardized or customized products, and such a management tool will facilitate organizational improvement and support innovative decision making processes for technical assistance in after-sales services.  “After–sales Service of Engineering Industrial Assets” comprises a proposal for a warranty management framework, with an account of the different methods that can be used to improve decision making in the different stages of the after-sales service management process, and strategies for strengthening the structure and foundations of the framework. A review of the fundamental issues and current research topics in warranty management and after sales services is also provided, which is exemplified by a case study. This book is intended for postgraduates, researchers and engineers who are interested in aftersales manageme...

  16. Assessment of power reliability and improvement potential by using ...

    African Journals Online (AJOL)

    This paper presents the use of smart reclosers for improving reliability of a distribution system of one of the major cities of Ethiopia. As frequent power interruptions are posing a huge problem to the life of the people and the economy, finding a solution to the problem is very essential. Electric reliability has affected social well ...

  17. 40 CFR 85.2111 - Warranty enforcement.

    Science.gov (United States)

    2010-07-01

    ... for performance of a vehicle repair made pursuant to this subpart, and (4) Failure of a manufacturer... in paragraph (d) of this section: (a) Selling or leasing a light duty vehicle without providing in... and conditions of the Emission Performance Warranty with respect to any vehicle to which this subpart...

  18. SOFC Systems with Improved Reliability and Endurance

    Energy Technology Data Exchange (ETDEWEB)

    Ghezel-Ayagh, Hossein [Fuelcell Energy, Incorporated, Danbury, CT (United States)

    2015-12-31

    The overall goal of this U.S. Department of Energy (DOE) sponsored project was the development of Solid Oxide Fuel Cell (SOFC) technology suitable for ultra-efficient central power generation systems utilizing coal and natural gas fuels and featuring greater than 90% carbon dioxide capture. The specific technical objective of this project was to demonstrate, via analyses and testing, progress towards adequate stack life (≥ 4 years) and stack performance stability (degradation rate ≤ 0.2% per 1000 hours) in a low-cost SOFC stack design. This final technical report summarizes the progress made during the project period of 27 months. Significant progress was made in the areas of cell and stack technology development, stack module development, sub-scale module tests, and Proof-of-Concept Module unit design, fabrication and testing. The work focused on cell and stack materials and designs, balance-of-plant improvements, and performance evaluation covering operating conditions and fuel compositions anticipated for commercially-deployed systems. In support of performance evaluation under commercial conditions, this work included the design, fabrication, siting, commissioning, and operation of a ≥ 50 kWe proof-of-concept module (PCM) power plant, based upon SOFC cell and stack technology developed to date by FuelCell Energy, Inc. (FCE) under the Office of Fossil Energy’s Solid Oxide Fuel Cells program. The PCM system was operated for at least 1000 hours on natural gas fuel at FCE’s facility. The factory cost of the SOFC stack was estimated to be at or below the DOE’s high-volume production cost target (2011 $).

  19. An empirical model to describe performance degradation for warranty abuse detection in portable electronics

    International Nuclear Information System (INIS)

    Oh, Hyunseok; Choi, Seunghyuk; Kim, Keunsu; Youn, Byeng D.; Pecht, Michael

    2015-01-01

    Portable electronics makers have introduced liquid damage indicators (LDIs) into their products to detect warranty abuse caused by water damage. However, under certain conditions, these indicators can exhibit inconsistencies in detecting liquid damage. This study is motivated by the fact that the reliability of LDIs in portable electronics is suspected. In this paper, first, the scheme of life tests is devised for LDIs in conjunction with a robust color classification rule. Second, a degradation model is proposed by considering the two physical mechanisms—(1) phase change from vapor to water and (2) water transport in the porous paper—for LDIs. Finally, the degradation model is validated with additional tests using actual smartphone sets subjected to the thermal cycling of −15 °C to 25 °C and the relative humidity of 95%. By employing the innovative life testing scheme and the novel performance degradation model, it is expected that the performance of LDIs for a particular application can be assessed quickly and accurately. - Highlights: • Devise an efficient scheme of life testing for a warranty abuse detector in portable electronics. • Develop a performance degradation model for the warranty abuse detector used in portable electronics. • Validate the performance degradation model with life tests of actual smartphone sets. • Help make a decision on warranty service in portable electronics manufacturers

  20. Strategy for continuous improvement in IC manufacturability, yield, and reliability

    Science.gov (United States)

    Dreier, Dean J.; Berry, Mark; Schani, Phil; Phillips, Michael; Steinberg, Joe; DePinto, Gary

    1993-01-01

    Continual improvements in yield, reliability and manufacturability measure a fab and ultimately result in Total Customer Satisfaction. A new organizational and technical methodology for continuous defect reduction has been established in a formal feedback loop, which relies on yield and reliability, failed bit map analysis, analytical tools, inline monitoring, cross functional teams and a defect engineering group. The strategy requires the fastest detection, identification and implementation of possible corrective actions. Feedback cycle time is minimized at all points to improve yield and reliability and reduce costs, essential for competitiveness in the memory business. Payoff was a 9.4X reduction in defectivity and a 6.2X improvement in reliability of 256 K fast SRAMs over 20 months.

  1. Reliability improvement: where do we go from here

    International Nuclear Information System (INIS)

    Haueter, R.L.

    1976-01-01

    The present programs and the future plans in the area of power-plant productivity and reliability data collection and analyses are discussed. The shortcomings of the past industry efforts toward improving plant productivity are described, and some suggestions for improvement are presented

  2. Improving Reliability, Security, and Efficiency of Reconfigurable Hardware Systems (Habilitation)

    NARCIS (Netherlands)

    Ziener, Daniel

    2017-01-01

    In this treatise,  my research on methods to improve efficiency, reliability, and security of reconfigurable hardware systems, i.e., FPGAs, through partial dynamic reconfiguration is outlined. The efficiency of reconfigurable systems can be improved by loading optimized data paths on-the-fly on an

  3. Cost benefit justification of nuclear plant reliability improvement

    International Nuclear Information System (INIS)

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

    1986-01-01

    Nuclear power costs are evaluated on the bases of general ground rules (a) vary from time to time (b) vary from country to another (c) even vary from one reactor type to another. The main objective of an electric utility is to provide the electric energy to the different consummers at the lowest possible cost with reasonable reliability level. Rapid increase of the construction costs and fuel prices in recent years have stimulated a great deal of interest in improving the reliability and productivity of new and existing power plants. One of the most important areas is the improvement of the secondary steam loop and the reactor cooling system. The method for evaluating the reliability of steam loop and cooling system utilizes the cut-set technique. The developed method can be easily used to show to what extent the overall reliability of the nuclear plant is affected by the possible failures in the steam and cooling subsystem. The cost reliability trade-off analysis is used to evaluate alternative schemes in the design with a view towards meeting a high reliability goal. Based on historical or estimated failure and repair rate, the reliability of the alternate scheme can be calculated

  4. Improving the Reliability of Case-Based Reasoning Systems

    Directory of Open Access Journals (Sweden)

    Xu Xu

    2010-09-01

    also discussed in this paper, especially the property that whether inter-feature of case exists redundancy. After that, the reliability of an individual suggested solution is studied. To illustrate these ideas, some experiments and their results are discussed in this paper. The results of experiments show a new route concerning on how to improve the reliability of a CBR system at an overall level.

  5. Technology and equipment to improve reliability of pipeline transport

    Science.gov (United States)

    Suleimanov, D. F.; Shulayev, N. S.; Bondar, K. E.; Laponov, S. V.; Uzinger, A. A.

    2017-10-01

    The article is dedicated to development of technology and hardware design of method pipeline transport reliability improving by improving the isolated coating properties modified by microwave radiation. The article describes the technology of the modification process of the coating and instrumentation production, which allows improving operational properties not only in stationary conditions in the manufacture of the insulation coating, but also during its replacement in the field.

  6. Cost benefit justification of nuclear plant reliability improvement

    International Nuclear Information System (INIS)

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

    1985-01-01

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

  7. On Improving Reliability of SRAM-Based Physically Unclonable Functions

    Directory of Open Access Journals (Sweden)

    Arunkumar Vijayakumar

    2017-01-01

    Full Text Available Physically unclonable functions (PUFs have been touted for their inherent resistance to invasive attacks and low cost in providing a hardware root of trust for various security applications. SRAM PUFs in particular are popular in industry for key/ID generation. Due to intrinsic process variations, SRAM cells, ideally, tend to have the same start-up behavior. SRAM PUFs exploit this start-up behavior. Unfortunately, not all SRAM cells exhibit reliable start-up behavior due to noise susceptibility. Hence, design enhancements are needed for improving reliability. Some of the proposed enhancements in literature include fuzzy extraction, error-correcting codes and voting mechanisms. All enhancements involve a trade-off between area/power/performance overhead and PUF reliability. This paper presents a design enhancement technique for reliability that improves upon previous solutions. We present simulation results to quantify improvement in SRAM PUF reliability and efficiency. The proposed technique is shown to generate a 128-bit key in ≤0.2 μ s at an area estimate of 4538 μ m 2 with error rate as low as 10 − 6 for intrinsic error probability of 15%.

  8. Some approaches to system reliability improvement in engineering design

    International Nuclear Information System (INIS)

    Shen, Kecheng.

    1990-01-01

    In this thesis some approaches to system reliability improvement in engineering design are studied. In particular, the thesis aims at developing alternative methodologies for ranking of component importance which are more related to the design practice and which are more useful in system synthesis than the existing ones. It also aims at developing component reliability models by means of stress-strength interference which will enable both component reliability prediction and design for reliability. A new methodology for ranking of component importance is first developed based on the notion of the increase of the expected system yield. This methodology allows for incorporation of different improvement actions at the component level such as parallel redundancy, standby redundancy, burn-in, minimal repair and perfect replacement. For each of these improvement actions, the increase of system reliability is studied and used as the component importance measure. A possible connection between the commonly known models of component lifetimes and the stress-strength interference models is suggested. Under some general conditions the relationship between component failure rate and the stress and strength distribution characteristics is studied. A heuristic approach for obtaining bounds on failure probability through stress-strength interference is also presented. A case study and a worked example are presented, which illustrate and verify the developed importance measures and their applications in the analytical as well as synthetical work of engineering design. (author)

  9. Designing incentive market mechanisms for improving restructured power system reliabilities

    DEFF Research Database (Denmark)

    Ding, Yi; Østergaard, Jacob; Wu, Qiuwei

    2011-01-01

    state. The reliability management of producers usually cannot be directly controlled by the system operators in a restructured power system. Producers may have no motivation to improve their reliabilities, which can result in serious system unreliability issues in the new environment. Incentive market...... mechanisms for improving the restructured power system reliabilities have been designed in this paper. In the proposed incentive mechanisms, penalty will be implemented on a producer if the failures of its generator(s) result in the variation of electricity prices. Incentive market mechanisms can motivate......In a restructured power system, the monopoly generation utility is replaced by different electricity producers. There exists extreme price volatility caused by random failures by generation or/and transmission systems. In these cases, producers' profits can be much higher than those in the normal...

  10. System ergonomics as an approach to improve human reliability

    International Nuclear Information System (INIS)

    Bubb, H.

    1988-01-01

    The application of system technics on ergonomical problems is called system ergonomics. This enables improvements of human reliability by design measures. The precondition for this is the knowledge of how information processing is performed by man and machine. By a separate consideration of sensory processing, cognitive processing, and motory processing it is possible to have a more exact idea of the system element 'man'. The system element 'machine' is well described by differential equations which allow an ergonomical assessment of the manouverability. The knowledge of information processing of man and machine enables a task analysis. This makes appear on one hand the human boundaries depending on the different properties of the task and on the other hand suitable ergonomical solution proposals which improve the reliability of the total system. It is a disadvantage, however, that the change of human reliability by such measures may not be quoted numerically at the moment. (orig.)

  11. Improvement on reliability of control system in power plant

    International Nuclear Information System (INIS)

    Taguchi, S.; Mizumoto, T.; Hirose, Y.; Kashiwai, J.; Takami, I.; Shono, M.; Roji, Y.; Kizaki, S.

    1985-01-01

    Studies made of Japanese PWR operating experiences have revealed that failures in the control system are the primary causes of unscheduled shutdowns. An attempt has, therefore, been made to improve the reliability of the control system in order to raise the plant reliability. The following are the procedures applied to solve the issue; study of operating experiences, fault tree analysis and failure mode and effects analysis. Improvement measures are developed for the control system whose failure threatens to cause the plant trip during the plant life. These systems are the main feedwater control system, rod control system, pressurizer control system and main steam control system in the primary control system. As a result, the plant unavailability is expected to be reduced significantly by applying the improvements. The improvements are applied to the plants under construction and the operating plants in co-operation with utilities and vendors. (author)

  12. Developing a system engineering program to improve performance and reliability

    International Nuclear Information System (INIS)

    Keuter, D.

    1985-01-01

    After several maintenance, operational, and equipment problems last year, Trojan set out on a mission to improve plant performance and reliability by strengthening its on-site engineering organization. This paper presents Trojan's plans in developing an on-site system engineering organization

  13. 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)

  14. Reliability improvement of multiversion software by exchanging modules

    International Nuclear Information System (INIS)

    Shima, Kazuyuki; Matsumoto, Ken-ichi; Torii, Koji

    1996-01-01

    In this paper, we proposes a method to improve reliability of multiversion software. In CER proposed in, checkpoints are put in versions of program and errors of versions are detected and recovered at the checkpoints. It prevent versions from failing and improve the reliability of multiversion software. But it is point out that CER decreases the reliability of the multiversion software if the detection and recovery of errors are assumed to be able to fail. In the method proposed in this paper, versions of program are developed following the same module specifications. When failures of versions of program are detected, faulty modules are identified and replaced them to other modules. It create versions without faulty modules and improve the reliability of multiversion software. The failure probability of multiversion software is estimated to become about a hundredth of the failure probability by the proposed method where the failure probability of each version is 0.000698, the number of versions is 5 and the number of modules is 20. (author)

  15. 48 CFR 252.246-7001 - Warranty of data.

    Science.gov (United States)

    2010-10-01

    ... exceed ten percent of the total contract price. (ii) If the breach of the warranty is with respect to the..., DEPARTMENT OF DEFENSE CLAUSES AND FORMS SOLICITATION PROVISIONS AND CONTRACT CLAUSES Text of Provisions And... contract entitled, Rights in Technical Data and Computer Software. (b) Warranty. Notwithstanding inspection...

  16. The redesign of a warranty distribution network with recovery processes

    NARCIS (Netherlands)

    Ashayeri, J.; Ma, N.; Sotirov, R.

    A warranty distribution network provides aftersales warranty services to customers and resembles a closed-loop supply chain network with specific challenges for reverse flows management like recovery, repair, and reflow of refurbished products. We present here a nonlinear and nonconvex mixed integer

  17. 48 CFR 252.246-7002 - Warranty of construction (Germany).

    Science.gov (United States)

    2010-10-01

    ... workmanship performed. (d) The Contractor shall restore any work damaged in fulfilling the terms and... damage at the Contractor's expense. (g) With respect to all warranties, express or implied, from... all warranties to be executed in writing, for the benefit of the Government, if directed by the...

  18. 48 CFR 52.246-21 - Warranty of Construction.

    Science.gov (United States)

    2010-10-01

    ... restore any work damaged in fulfilling the terms and conditions of this clause. The Contractor's warranty.... (g) With respect to all warranties, express or implied, from subcontractors, manufacturers, or... executed, in writing, for the benefit of the Government, if directed by the Contracting Officer; and (3...

  19. 78 FR 69018 - Improving the Resiliency of Mobile Wireless Communications Networks; Reliability and Continuity...

    Science.gov (United States)

    2013-11-18

    ... consumers value overall network reliability and quality in selecting mobile wireless service providers, they...-125] Improving the Resiliency of Mobile Wireless Communications Networks; Reliability and Continuity... (Reliability NOI) in 2011 to ``initiate a comprehensive examination of issues regarding the reliability...

  20. A Study of Standardized Headings for Warranties. Technical Report No. 6.

    Science.gov (United States)

    Charrow, Veda R.; Redish, Janice C.

    A study was conducted (1) to discover whether using standardized headings on warranties would increase or decrease people's speed and accuracy in understanding the terms of warranties and (2) to determine what effect headings would have on people's attitudes toward warranties. Subjects were 48 adult consumers who read groups of four warranties for…

  1. Reliability improvement methods for sapphire fiber temperature sensors

    Science.gov (United States)

    Schietinger, C.; Adams, B.

    1991-08-01

    Mechanical, optical, electrical, and software design improvements can be brought to bear in the enhancement of fiber-optic sapphire-fiber temperature measurement tool reliability in harsh environments. The optical fiber thermometry (OFT) equipment discussed is used in numerous process industries and generally involves a sapphire sensor, an optical transmission cable, and a microprocessor-based signal analyzer. OFT technology incorporating sensors for corrosive environments, hybrid sensors, and two-wavelength measurements, are discussed.

  2. Monolithic QCL design approaches for improved reliability and affordability

    Science.gov (United States)

    Law, K. K.

    2013-12-01

    Many advances have been made recently in mid-wave infrared and long-wave infrared quantum cascade lasers (QCLs) technologies, and there is an increasing demand for these laser sources for ever expanding Naval, DoD and homeland security applications. We will discuss in this paper a portfolio of various Naval Air Warfare Weapons Division's current and future small business innovative research programs and efforts on significantly improving QCLs' performance, affordability, and reliability.

  3. 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.

  4. Improved FTA methodology and application to subsea pipeline reliability design.

    Science.gov (United States)

    Lin, Jing; Yuan, Yongbo; Zhang, Mingyuan

    2014-01-01

    An innovative logic tree, Failure Expansion Tree (FET), is proposed in this paper, which improves on traditional Fault Tree Analysis (FTA). It describes a different thinking approach for risk factor identification and reliability risk assessment. By providing a more comprehensive and objective methodology, the rather subjective nature of FTA node discovery is significantly reduced and the resulting mathematical calculations for quantitative analysis are greatly simplified. Applied to the Useful Life phase of a subsea pipeline engineering project, the approach provides a more structured analysis by constructing a tree following the laws of physics and geometry. Resulting improvements are summarized in comparison table form.

  5. Grant Peer Review: Improving Inter-Rater Reliability with Training.

    Science.gov (United States)

    Sattler, David N; McKnight, Patrick E; Naney, Linda; Mathis, Randy

    2015-01-01

    This study developed and evaluated a brief training program for grant reviewers that aimed to increase inter-rater reliability, rating scale knowledge, and effort to read the grant review criteria. Enhancing reviewer training may improve the reliability and accuracy of research grant proposal scoring and funding recommendations. Seventy-five Public Health professors from U.S. research universities watched the training video we produced and assigned scores to the National Institutes of Health scoring criteria proposal summary descriptions. For both novice and experienced reviewers, the training video increased scoring accuracy (the percentage of scores that reflect the true rating scale values), inter-rater reliability, and the amount of time reading the review criteria compared to the no video condition. The increase in reliability for experienced reviewers is notable because it is commonly assumed that reviewers--especially those with experience--have good understanding of the grant review rating scale. The findings suggest that both experienced and novice reviewers who had not received the type of training developed in this study may not have appropriate understanding of the definitions and meaning for each value of the rating scale and that experienced reviewers may overestimate their knowledge of the rating scale. The results underscore the benefits of and need for specialized peer reviewer training.

  6. System 80+ Design and Licensing : Improving Plant Reliability

    International Nuclear Information System (INIS)

    Newman, Robert E.

    1989-01-01

    The U. S. nuclear industry is striving to improve plant reliability and availability through improved plant design, component designs and plant maintenance. In an effort to improve safety and to demonstrate that commercial nuclear power is economically competitive with other energy sources, the utilities, nuclear vendors, architect engineers and constructors, and component suppliers are all participating in an industry-wide effort to develop improved Light Water Reactor (LWR) designs that are based upon the many years of successful LWR operation. In an age when the world faces the environmental pressures of the greenhouse effect and acid rain, electricity generated from nuclear energy must play an increasing role in the energy picture of Korea, the United States and the rest of the world. This paper discusses the plant availability requirement that has been established by the industry-wide effort mentioned above. After briefly describing Combustion Engineering's program for development of the System 80 Plus standard design and the participation of the Korea Advanced Energy Research Institute (KAERI) in the program, the paper then describes the design features that are being incorporated into System 80+. The industry ALRR Program has established a very ambitious criterion of 87% for the plant availability of future nuclear units. To satisfy such a requirement, the next generation of nuclear plants will include a great many design improvements that reflect the hundreds of years of operating experience that we have accrued. C-ESA's System 80+ will include a number of design changes that improve operating margins and make the plant easier to operate and maintain. Not surprisingly, there is a great deal of overlap between improved safety and improved reliability. In the end, our design will satisfy the future needs of the utilities, the regulators, and the public. C-E is very pleased that KAERI is working with US to achieve these important goals

  7. The commissioning of CMS sites: Improving the site reliability

    International Nuclear Information System (INIS)

    Belforte, S; Fisk, I; Flix, J; Hernandez, J M; Klem, J; Letts, J; Magini, N; Saiz, P; Sciaba, A

    2010-01-01

    The computing system of the CMS experiment works using distributed resources from more than 60 computing centres worldwide. These centres, located in Europe, America and Asia are interconnected by the Worldwide LHC Computing Grid. The operation of the system requires a stable and reliable behaviour of the underlying infrastructure. CMS has established a procedure to extensively test all relevant aspects of a Grid site, such as the ability to efficiently use their network to transfer data, the functionality of all the site services relevant for CMS and the capability to sustain the various CMS computing workflows at the required scale. This contribution describes in detail the procedure to rate CMS sites depending on their performance, including the complete automation of the program, the description of monitoring tools, and its impact in improving the overall reliability of the Grid from the point of view of the CMS computing system.

  8. 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

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

    Science.gov (United States)

    Dumas, L. N.; Shumka, A.

    1982-01-01

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

  10. Improving inspection reliability through operator selection and training

    International Nuclear Information System (INIS)

    McGrath, Bernard; Carter, Luke

    2013-01-01

    A number of years ago the UK's Health and Safety Executive sponsored a series of three PANI projects investigating the application of manual ultrasonics, which endeavoured to establish the necessary steps that ensure a reliable inspection is performed. The results of the three projects were each reported separately on completion and also presented at number of international conferences. This paper summarises the results of these projects from the point of view of operator performance. The correlation of operator ultrasonic performance with results of aptitude tests is presented along with observations on the impact of training and qualifications of the operators. The results lead to conclusions on how the selection and training of operators could be modified to improve reliability of inspections.

  11. Zero tolerance for failure. An AREVA initiative to improve reliability

    International Nuclear Information System (INIS)

    Lippert, Hans-Joachim; Gentet, Guy; Mollard, Pierre; Garner, Norman

    2010-01-01

    Significant improvements in fuel reliability have been realized over the past 2 decades, but total elimination of failures has remained elusive. Driving reliability to higher levels requires a philosophy that does not accept that even infrequent and isolated failures are inevitable - it was on this foundation that Areva's Zero Tolerance for Failure (ZTF) initiative was established. This is not in itself either a program or project, but a fundamental shift in the way of thinking about work according to the following four principles: - Failures are avoidable, - Zero failures are our goal, - We will respond rapidly to any failure, - We succeed when we fix failures in a way that precludes recurrence. The shift to a ZTF philosophy is a broad change in corporate culture that expands the concept of failure far beyond cases where fuel rod cladding integrity is breached. While this paper specifically illustrates the ways in which ZTF has shaped the company's response to enhancing fuel rod reliability, ZTF extends to any failures of fuel products to deliver expected levels of performance, manufacturing processes to meet specifications and high first-pass acceptance criteria, and beyond to error-free performance of engineering analyses and cycle design and licensing services. Application of ZTF to enhancing fuel reliability deploys efforts in the areas of manufacturing, human factors, design, R and D, processes and product strategy. In order to achieve the necessary improvements, a number of important actions have been initiated across regions and facilities. In addition to these global scale projects and measures, each region contributes by adopting measures which are relevant to its particular activities and market needs. (orig.)

  12. Improvement of Steam Generator Reliability for GEN-IV SFR

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seong O; Kim Se Yun; Kim, Seok Hoon; Eoh, Jae Hyuk; Lee, Hyeong Yeon; Choi, Byung Seon

    2005-11-15

    The R and D items performed in this study were selected from the R and D task of ' Reliability improvement of Steam Generator' of GEN-IV SFR Component Design and BOP. Since this project deals with one of the most important issues for a GEN-IV SFR system, it needs to enhance the domestic technical backgrounds associated with the corresponding R and D items even for a very short period by 2005. This study provides the R and D results for i) Development of assessment methodology for dissimilar metal weld and ii) Development of multi-dimensional simulation methodology for a SWR event in a SFR steam generator.

  13. Improvement of Steam Generator Reliability for GEN-IV SFR

    International Nuclear Information System (INIS)

    Kim, Seong O; Kim Se Yun; Kim, Seok Hoon; Eoh, Jae Hyuk; Lee, Hyeong Yeon; Choi, Byung Seon

    2005-11-01

    The R and D items performed in this study were selected from the R and D task of ' Reliability improvement of Steam Generator' of GEN-IV SFR Component Design and BOP. Since this project deals with one of the most important issues for a GEN-IV SFR system, it needs to enhance the domestic technical backgrounds associated with the corresponding R and D items even for a very short period by 2005. This study provides the R and D results for i) Development of assessment methodology for dissimilar metal weld and ii) Development of multi-dimensional simulation methodology for a SWR event in a SFR steam generator

  14. Improvement of Equipment reliability for Auxiliary Feed Water System

    Energy Technology Data Exchange (ETDEWEB)

    Deok, Lee Sang; Kwan, Lee Yong [KEPCO International Nuclear Graduate School, Ulsan (Korea, Republic of)

    2013-10-15

    According to AP913 ER) of INPO, Number of the event related to equipment is higher than others like external or human performance. In the top 25 systems, Auxiliary feed water system is the seventh highest among systems. AWFS consists of many component and complex system and Main Function of AFWS is to supply feedwater to the steam generators for the removal of heat from the RCS(Reactor Coolant System) in event the main feedwater system is unavailable following a transient or accident. Reliability of component means how well operate on demands and monitoring is necessary to keep track of condition of component. If component performance is lower than the required value, corrective action for failure mode should be done. The objective of this study is focused to improve of AF pump by adding the tasks of SHR(System Health Report) into the task of system engineer walkdown of PMT(Preventive Maintenance Template). Increasing the reliability of AF pump will contribute to improvement of reliability of AFWS. Based on operating history, there was high vibration of AF pump during performance test. In that case, there were a lot of maintenance works for normal operation of AF pump. Vibration problem related pump can't be detected by tasks of SE walkdown because it's not running during normal operation except for surveillance test. CHR(Component Health Report) of AF pump in AFWS can be made from necessary part which means monitoring and functional failure because problem of Stand-by pump can be covered by conducting monitoring and analysis of functional failure. To improve reliability of AF pump, walkdown of PMT and SHR should be conducted both in accordance with surveillance test frequency. Health of AF pump based on operation history can be verified first and then can find out which parts of pump are weak. Finally, weak part can be managed intensively and failure can be reduced according to SE walkdown. But this work can be risky and burdensome because all parts of

  15. Revised scoring and improved reliability for the Communication Patterns Questionnaire.

    Science.gov (United States)

    Crenshaw, Alexander O; Christensen, Andrew; Baucom, Donald H; Epstein, Norman B; Baucom, Brian R W

    2017-07-01

    The Communication Patterns Questionnaire (CPQ; Christensen, 1987) is a widely used self-report measure of couple communication behavior and is well validated for assessing the demand/withdraw interaction pattern, which is a robust predictor of poor relationship and individual outcomes (Schrodt, Witt, & Shimkowski, 2014). However, no studies have examined the CPQ's factor structure using analytic techniques sufficient by modern standards, nor have any studies replicated the factor structure using additional samples. Further, the current scoring system uses fewer than half of the total items for its 4 subscales, despite the existence of unused items that have content conceptually consistent with those subscales. These characteristics of the CPQ have likely contributed to findings that subscale scores are often troubled by suboptimal psychometric properties such as low internal reliability (e.g., Christensen, Eldridge, Catta-Preta, Lim, & Santagata, 2006). The present study uses exploratory and confirmatory factor analyses on 4 samples to reexamine the factor structure of the CPQ to improve scale score reliability and to determine if including more items in the subscales is warranted. Results indicate that a 3-factor solution (constructive communication and 2 demand/withdraw scales) provides the best fit for the data. That factor structure was confirmed in the replication samples. Compared with the original scales, the revised scales include additional items that expand the conceptual range of the constructs, substantially improve reliability of scale scores, and demonstrate stronger associations with relationship satisfaction and sensitivity to change in therapy. Implications for research and treatment are discussed. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  16. Advanced reliability improvement of AC-modules (ARIA)

    International Nuclear Information System (INIS)

    Rooij, P.; Real, M.; Moschella, U.; Sample, T.; Kardolus, M.

    2001-09-01

    The AC-module is a relatively new development in PV-system technology and offers significant advantages over conventional PV-systems with a central inverter : e.g. increased modularity, ease of installation and freedom of system design. The Netherlands and Switzerland have a leading position in the field of AC-modules, both in terms of technology and of commercial and large-scale application. An obstacle towards large-scale market introduction of AC-modules is that the reliability and operational lifetime of AC-modules and the integrated inverters in particular are not yet proven. Despite the advantages, no module-integrated inverter has yet achieved large scale introduction. The AC-modules will lower the barrier towards market penetration. But due to the great interest in the new AC-module technology there is the risk of introducing a not fully proven product. This may damage the image of PV-systems. To speed up the development and to improve the reliability, research institutes and PV-industry will address the aspects of reliability and operational lifetime of AC-modules. From field experiences we learn that in general the inverter is still the weakest point in PV-systems. The lifetime of inverters is an important factor on reliability. Some authors are indicating a lifetime of 1.5 years, whereas the field experiences in Germany and Switzerland have shown that for central inverter systems, an availability of 97% has been achieved in the last years. From this point of view it is highly desirable that the operational lifetime and reliability of PV-inverters and especially AC-modules is demonstrated/improved to make large scale use of PV a success. Module Integrated Inverters will most likely be used in modules in the power range between 100 and 300 Watt DC-power. These are modules with more than 100 cells in series, assuming that the module inverter will benefit from the higher voltage. Hot-spot is the phenomenon that can occur when one or more cells of a string

  17. Improved reliability of residential heat pumps; Foerbaettrad driftsaekerhet hos villavaermepumpar

    Energy Technology Data Exchange (ETDEWEB)

    Haglund Stignor, Caroline; Larsson, Kristin; Jensen, Sara; Larsson, Johan; Berg, Johan; Lidbom, Peter; Rolfsman, Lennart

    2012-07-01

    Today, heat pump heating systems are common in Swedish single-family houses. Many owners are pleased with their installation, but statistics show that a certain number of heat pumps break every year, resulting in high costs for both insurance companies and owners. On behalf of Laensfoersaekringars Forskningsfond, SP Energy Technology has studied the cause of the most common failures for residential heat pumps. The objective of the study was to suggest what measures to be taken to reduce the number of failures, i.e. improving the reliability of heat pumps. The methods used were analysis of public failure statistics and sales statistics and interviews with heat pump manufacturers, installers, service representatives and assessors at Laensfoersaekringar. In addition, heat pump manuals have been examined and literature searches for various methods for durability tests have been performed. Based on the outcome from the interviews the most common failures were categorized by if they; 1. Could have been prevented by better operation and maintenance of the heat pump. 2. Caused by a poorly performed installation. 3. Could have been prevented if certain parameters had been measured, recorded and followed up. 4. Are due to poor quality of components or systems. However, the results show that many of the common failures fall into several different categories and therefore, different types of measures must be taken to improve the operational reliability of residential heat pumps. The interviews tell that failures often are caused by poor installation, neglected maintenance and surveillance, and poor quality of standard components or that components are used outside their declared operating range. The quality of the installations could be improved by increasing installers' knowledge about heat pumps and by requiring that an installation protocol shall be filled-in. It is also important that the owner of the heat pump performs the preventive maintenance recommended by the

  18. Improved reliability of residential heat pumps; Foerbaettrad driftsaekerhet hos villavaermepumpar

    Energy Technology Data Exchange (ETDEWEB)

    Haglund Stignor, Caroline; Larsson, Kristin; Jensen, Sara; Larsson, Johan; Berg, Johan; Lidbom, Peter; Rolfsman, Lennart

    2012-07-01

    Today, heat pump heating systems are common in Swedish single-family houses. Many owners are pleased with their installation, but statistics show that a certain number of heat pumps break every year, resulting in high costs for both insurance companies and owners. On behalf of Laensfoersaekringars Forskningsfond, SP Energy Technology has studied the cause of the most common failures for residential heat pumps. The objective of the study was to suggest what measures to be taken to reduce the number of failures, i.e. improving the reliability of heat pumps. The methods used were analysis of public failure statistics and sales statistics and interviews with heat pump manufacturers, installers, service representatives and assessors at Laensfoersaekringar. In addition, heat pump manuals have been examined and literature searches for various methods for durability tests have been performed. Based on the outcome from the interviews the most common failures were categorized by if they; 1. Could have been prevented by better operation and maintenance of the heat pump. 2. Caused by a poorly performed installation. 3. Could have been prevented if certain parameters had been measured, recorded and followed up. 4. Are due to poor quality of components or systems. However, the results show that many of the common failures fall into several different categories and therefore, different types of measures must be taken to improve the operational reliability of residential heat pumps. The interviews tell that failures often are caused by poor installation, neglected maintenance and surveillance, and poor quality of standard components or that components are used outside their declared operating range. The quality of the installations could be improved by increasing installers' knowledge about heat pumps and by requiring that an installation protocol shall be filled-in. It is also important that the owner of the heat pump performs the preventive maintenance recommended by the

  19. Air-cooled steam condensers non-freeze warranties

    Energy Technology Data Exchange (ETDEWEB)

    Larinoff, M.W.

    1995-09-01

    What this paper is suggesting is the seller quote a condenser package with a LIMITED NON-FREEZE WARRANTY. Relieve the inexperienced buyer of the responsibility for selecting freeze protection design options. The seller cannot afford to over-design because of the added costs and the need for a competitive price. Yet he cannot under-design and allow the condenser tubes to freeze periodically and then pay the repair bills in accordance with the warranty.

  20. Improved reliability, maintainability and safety through elastomer upgrading

    International Nuclear Information System (INIS)

    Wensel, R.; Wittich, K.C.

    1995-01-01

    Equipment in nuclear plants has historically contained whatever elastomer each component supplier traditionally used for corresponding non-nuclear service. The resulting proliferation of elastomer compounds, many of which are far from optimal for the service conditions (e.g., pressure, temperature, radiation, etc.), has multiplied the costs to provide station reliability, maintainability and safety. Cost-effective improvements are being achieved in CANDU plants by upgrading and standardizing on a handful of high performing elastomer compounds. These upgraded materials offer significant gains in service life over the materials they replace (often by factors of 2 or more). This rationalization of elastomer compounds also facilitates the EQ process for safety-related equipment. Detailed test data on aging is currently being generated for these specific elastomers, encompassing the conditions and media (air, water, oil) common in CANDU service. Two key elements characterize this testing. First, each result is specific to the compound used in the test, and second, it is specific to the tested failure mode (e.g., compression set, extrusion, fracture, etc.). Having fewer, but more thoroughly tested compounds, avoids the penalty (associated with poorly characterized materials) of having to replace parts prematurely because of conservatism, while maintaining safe, reliable service. This paper provides an overview of this approach covering: the benefits of compound rationalization; and the how and why of establishing relevant failure criteria; appropriate quality assurance to maintain EQ; procurement, storage and handling guidelines; and monitoring and predicting in-service degradation. (author)

  1. Improving Electronic Sensor Reliability by Robust Outlier Screening

    Directory of Open Access Journals (Sweden)

    Federico Cuesta

    2013-10-01

    Full Text Available Electronic sensors are widely used in different application areas, and in some of them, such as automotive or medical equipment, they must perform with an extremely low defect rate. Increasing reliability is paramount. Outlier detection algorithms are a key component in screening latent defects and decreasing the number of customer quality incidents (CQIs. This paper focuses on new spatial algorithms (Good Die in a Bad Cluster with Statistical Bins (GDBC SB and Bad Bin in a Bad Cluster (BBBC and an advanced outlier screening method, called Robust Dynamic Part Averaging Testing (RDPAT, as well as two practical improvements, which significantly enhance existing algorithms. Those methods have been used in production in Freescale® Semiconductor probe factories around the world for several years. Moreover, a study was conducted with production data of 289,080 dice with 26 CQIs to determine and compare the efficiency and effectiveness of all these algorithms in identifying CQIs.

  2. Improving the reliability of fishery predictions under climate change

    DEFF Research Database (Denmark)

    Brander, Keith

    2015-01-01

    The increasing number of publications assessing impacts of climate change on marine ecosystems and fisheries attests to rising scientific and public interest. A selection of recent papers, dealing more with biological than social and economic aspects, is reviewed here, with particular attention...... to the reliability of projections of climate impacts on future fishery yields. The 2014 Intergovernmental Panel on Climate Change (IPCC) report expresses high confidence in projections that mid- and high-latitude fish catch potential will increase by 2050 and medium confidence that low-latitude catch potential...... understanding of climate impacts, such as how to improve coupled models from physics to fish and how to strengthen confidence in analysis of time series...

  3. Developing Predictive Maintenance Expertise to Improve Plant Equipment Reliability

    International Nuclear Information System (INIS)

    Wurzbach, Richard N.

    2002-01-01

    On-line equipment condition monitoring is a critical component of the world-class production and safety histories of many successful nuclear plant operators. From addressing availability and operability concerns of nuclear safety-related equipment to increasing profitability through support system reliability and reduced maintenance costs, Predictive Maintenance programs have increasingly become a vital contribution to the maintenance and operation decisions of nuclear facilities. In recent years, significant advancements have been made in the quality and portability of many of the instruments being used, and software improvements have been made as well. However, the single most influential component of the success of these programs is the impact of a trained and experienced team of personnel putting this technology to work. Changes in the nature of the power generation industry brought on by competition, mergers, and acquisitions, has taken the historically stable personnel environment of power generation and created a very dynamic situation. As a result, many facilities have seen a significant turnover in personnel in key positions, including predictive maintenance personnel. It has become the challenge for many nuclear operators to maintain the consistent contribution of quality data and information from predictive maintenance that has become important in the overall equipment decision process. These challenges can be met through the implementation of quality training to predictive maintenance personnel and regular updating and re-certification of key technology holders. The use of data management tools and services aid in the sharing of information across sites within an operating company, and with experts who can contribute value-added data management and analysis. The overall effectiveness of predictive maintenance programs can be improved through the incorporation of newly developed comprehensive technology training courses. These courses address the use of

  4. Use of Human Reliability Insights to Improve Decision-Making

    International Nuclear Information System (INIS)

    Julius, J. A.; Moieni, P.; Grobbelaar, J.; Kohlhepp, K.

    2016-01-01

    This paper describes the use of insights obtained during the development and application of human reliability analysis (HRA) as part of a probabilistic risk assessment (PRA) to support decision-making, including improvements to operations, training, and safety culture. Insights have been gained from the development and application of HRA as part of a PRA for nuclear power plants in the USA, Europe and Asia over the last two decades. These models consist of Level 1 and Level 2 PRA models of internal and external events, during full power and shutdown modes of plant operation. These insights include the use of human factors information to improve the qualitative portion of the HRA. The subsequent quantification in the HRA effectively prioritises the contributors to the unreliability of operator actions, and the process facilitates the identification of the factors that are important to the success of the operator actions. Additionally, the tools and techniques also allow for the evaluation of key assumptions and sources of uncertainty. The end results have been used to effectively support decision-making for day-to-day plant operations as well as licensing issues. HRA results have been used to provide feedback and improvements to plant procedures, operator training and other areas contributing the plant safety culture. Examples of the types of insights are presented in this paper. (author)

  5. Improvement of human reliability analysis method for PRA

    International Nuclear Information System (INIS)

    Tanji, Junichi; Fujimoto, Haruo

    2013-09-01

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

  6. Improving reliability in south Ajax with IntelliTEAM

    Energy Technology Data Exchange (ETDEWEB)

    Starck, A.P. [Veridian Connections Inc., Ajax, ON (Canada)

    2010-07-01

    Veridian Connections Incorporated is a local electricity distribution company in Ontario that is faced with end of life feeder cables and an aging system. Most of the feeders are combined overhead and underground cables supplied from several substations with a limited transfer capability. The commercial activity in the utility's service area is intolerant to sustained outages. Although the initial plan was to replace the cables, capital and time constraints led the utility to chose the IntelliTEAM 2 system to improve reliability, by reducing the frequency, duration and impact of outages. The unique system is based on submersible switchgear, PulseClosing and includes the substation breakers as IntelliTEAM devices. The current plan to implement a smart grid turns sustained outages into momentary outages; reduces the number of customers affected by a sustained failure; improves the ability to transfer loads; and reduces stresses on aged cables. The self healing system restores customers in less than a minute and provides visibility to SCADA operators through a high speed SpeedNet radio system. tabs., figs.

  7. 31 CFR 355.5 - What warranties does a presenting bank make?

    Science.gov (United States)

    2010-07-01

    ... limit any warranty by a presenter or other party arising under State law. (b) We are not barred from recovering on a breach of warranty solely because: (1) Our negligence contributed to a fraudulent endorsement...

  8. Domestic manufacturing and reliability improvement of reactor water recirculation equipment

    International Nuclear Information System (INIS)

    Kobayashi, Hidekazu; Oi, Masao; Shida, Toichi; Yokomori, Takashi

    1982-01-01

    The reactor coolant recirculation system is one of the important systems to control the reactor output in BWR nuclear power plants. Its components require high reliability and maintainability as well as controllability. For many Japanese nuclear power plants, recirculation pumps, fluid couplings and others have been imported so far. Hitachi Ltd. has established a domestic manufacturing organization through the development and test of these equipment. The fundamental design conditions for these equipment are the improvement of the rate of utilization of plant facility, the capability to follow load, and output power stability. In this paper, the specifications, the investigation of moment of inertia and the design features of recirculation pumps, driving motors and variable frequency power supply systems are described. The paper also reports on the combination test implemented to evaluate the recirculation system. The combination test includes the test using water rheostat for the power source facility and the loading test for a recirculation pump. The application of those system equipment to an actual plant was analyzed and evaluated on a basis of the test data obtained. The result showed that the equipment can achieve the rate of change of reactor power of 30%/min. Those equipment have been employed for No. 2 reactor plant of the Fukushima No. 2 Nuclear Power Station, the Tokyo Electric Power Co., Inc. (Wakatsuki, Y.)

  9. Diversity combining in laser Doppler vibrometry for improved signal reliability

    International Nuclear Information System (INIS)

    Dräbenstedt, Alexander

    2014-01-01

    Because of the speckle nature of the light reflected from rough surfaces the signal quality of a vibrometer suffers from varying signal power. Deep signal outages manifest themselves as noise bursts and spikes in the demodulated velocity signal. Here we show that the signal quality of a single point vibrometer can be substantially improved by diversity reception. This concept is widely used in RF communication and can be transferred into optical interferometry. When two statistically independent measurement channels are available which measure the same motion on the same spot, the probability for both channels to see a signal drop-out at the same time is very low. We built a prototype instrument that uses polarization diversity to constitute two independent reception channels that are separately demodulated into velocity signals. Send and receive beams go through different parts of the aperture so that the beams can be spatially separated. The two velocity channels are mixed into one more reliable signal by a PC program in real time with the help of the signal power information. An algorithm has been developed that ensures a mixing of two or more channels with minimum resulting variance. The combination algorithm delivers also an equivalent signal power for the combined signal. The combined signal lacks the vast majority of spikes that are present in the raw signals and it extracts the true vibration information present in both channels. A statistical analysis shows that the probability for deep signal outages is largely decreased. A 60 fold improvement can be shown. The reduction of spikes and noise bursts reduces the noise in the spectral analysis of vibrations too. Over certain frequency bands a reduction of the noise density by a factor above 10 can be shown

  10. Study on the improvement of nuclear fuel cladding reliability

    International Nuclear Information System (INIS)

    Rheem, Karp Soon; Han, Jung Ho; Jeong, Yong Hwan; Lee, Deok Hyun

    1987-12-01

    In order to improve the nuclear fuel cladding reliability for high burn-up fuels, the corrosion resistance of laser beam surface treated and β-quenched zircaloys and the mechanical characteristics including fatigue, burst, and out-of-pile PCMI characteristics of heat treated zircaloys were investigated. In addition, the inadiation characteristics of Ko-Ri reactor fuel claddings was examined. It was found that the wasteside corrosion resistance of commercial zircaloys was improved remarkably by laser beam surface treatment. The out-of-pile transient cladding failures were investigated in terms of hoop stress versus time-to-failures by means of mandrel loading units at 25 deg C and 325 deg C. Fatigue characteristics of the β-quenched and as-received zircaloy cladding were investigated by using an internal oil pressurization method which can simulate the load-following operation cycle. The results were in good agreement with the existing data obtained by conventional methods for commercial zircaloys. Burst tests were performed with commercial and the β-quenched zircaloys in high pressure argon gas atmosphere as a function of burst temperature. The burst stress decreased linearly in the α phase region up to 600 deg C and hereafter the decrement of the burst stress decreased gradually with temperature in the β-phase region. For the first time, the burst characteristic of the irradiated zircaloy-4 cladding tubes released from Ko-Ri nuclear power unit 1 was investigated, and attempts were made to trace the cause of cladding failures by examining the failed structure and fret marks by debris. (Author)

  11. 16 CFR 239.2 - Disclosures in warranty or guarantee advertising.

    Science.gov (United States)

    2010-01-01

    ... warranty coverage. These examples are for both print and broadcast advertising. These examples are... advertising. 239.2 Section 239.2 Commercial Practices FEDERAL TRADE COMMISSION GUIDES AND TRADE PRACTICE RULES GUIDES FOR THE ADVERTISING OF WARRANTIES AND GUARANTEES § 239.2 Disclosures in warranty or guarantee...

  12. 48 CFR 3046.791-2 - Tailoring warranty terms and conditions (USCG).

    Science.gov (United States)

    2010-10-01

    ... appropriately tailor the warranty on a case-by-case basis, including remedies, exclusions, limitations and... warranty certain defects for specified supplies (exclusions) and may limit the contractor's liability under... had not designed the system). (d) Contracting officers shall not include in a warranty clause any...

  13. An accurate and efficient reliability-based design optimization using the second order reliability method and improved stability transformation method

    Science.gov (United States)

    Meng, Zeng; Yang, Dixiong; Zhou, Huanlin; Yu, Bo

    2018-05-01

    The first order reliability method has been extensively adopted for reliability-based design optimization (RBDO), but it shows inaccuracy in calculating the failure probability with highly nonlinear performance functions. Thus, the second order reliability method is required to evaluate the reliability accurately. However, its application for RBDO is quite challenge owing to the expensive computational cost incurred by the repeated reliability evaluation and Hessian calculation of probabilistic constraints. In this article, a new improved stability transformation method is proposed to search the most probable point efficiently, and the Hessian matrix is calculated by the symmetric rank-one update. The computational capability of the proposed method is illustrated and compared to the existing RBDO approaches through three mathematical and two engineering examples. The comparison results indicate that the proposed method is very efficient and accurate, providing an alternative tool for RBDO of engineering structures.

  14. New Methods for Building-In and Improvement of Integrated Circuit Reliability

    NARCIS (Netherlands)

    van der Pol, J.A.; van der Pol, Jacob Antonius

    2000-01-01

    Over the past 30 years the reliability of semiconductor products has improved by a factor of 100 while at the same time the complexity of the circuits has increased by a factor 105. This 7-decade reliability improvement has been realised by implementing a sophisticated reliability assurance system

  15. Improving Metrological Reliability of Information-Measuring Systems Using Mathematical Modeling of Their Metrological Characteristics

    Science.gov (United States)

    Kurnosov, R. Yu; Chernyshova, T. I.; Chernyshov, V. N.

    2018-05-01

    The algorithms for improving the metrological reliability of analogue blocks of measuring channels and information-measuring systems are developed. The proposed algorithms ensure the optimum values of their metrological reliability indices for a given analogue circuit block solution.

  16. Fuel R and D to improve fuel reliability

    International Nuclear Information System (INIS)

    Yang, Rosa; Cheng, Bo; Deshon, Jeff; Edsinger, Kurt; Ozer, Odelli

    2006-01-01

    Light water reactor fuel is operating in an increasingly challenging environment. Fuel burnup extension and cycle length increase both can increase the local duty. Reactor water chemistry modifications for the purpose of protection the plant system materials have the potential of increasing fuel surface deposition and cladding corrosion and hydriding. The status of fuel performance in US reactors is summarized and an update of the Fuel Reliability Program' established by the utility industry to ensure reliability is provided. (author)

  17. Evaluation and improvement in nondestructive examination (NDE) reliability for inservice inspection of light water reactors

    International Nuclear Information System (INIS)

    Doctor, S.R.; Andersen, E.S.; Bowey, R.E.; Diaz, A.A.; Good, M.S.; Heasler, P.G.; Hockey, R.L.; Simonen, F.A.; Spanner, J.C.; Taylor, T.T.; Vo, T.V.

    1991-01-01

    This program is intended to establish the effectiveness, reliability and adequacy of inservice inspection of reactor pressure vessels and primary piping systems and the impact of ISI reliability on system integrity. The objectives of the program include: (a) determine the effectiveness and reliability of ultrasonic inservice inspection (ISI) performed on commercial, light water reactor pressure vessels and piping; (b) recommend Code changes to the inspection procedures to improve the reliability of ISI; (c) using fracture mechanics analysis, determine the impact of NDE unreliability on system safety and determine the level of inspection reliability required to assure a suitably low failure probability; (d) evaluate the degree of reliability improvement which could be achieved using improved NDE techniques; and (e) based on importance of component to safety, material properties, service conditions, and NDE uncertainties, formulate improved inservice inspection criteria (including sampling plan, frequency, and reliability of inspection) for revisions to ASME Section XI and regulatory requirements needed to assure suitably low failure probabilities

  18. International cooperation - a way to improve reliability and safety

    International Nuclear Information System (INIS)

    John, A.

    1998-01-01

    The mission of the World Association of Nuclear Operators (WANO) is highlighted, and WANO's Peer Review programme is described. At the Dukovany nuclear power plant, a Peer Review was undertaken in December 1997. The results gave evidence of a good level of safety, reliability and culture of operation of the plant. (P.A.)

  19. Improvement of AC motor reliability from technique standardization

    International Nuclear Information System (INIS)

    Muniz, P.R.; Faria, M.D.R.; Mendes, M.P.; Silva, J.N.; Dos Santos, J.D.

    2005-01-01

    The purpose of this paper is to explain the increase of reliability of motors serviced in the Electrical Maintenance Shop of Companhia Siderurgica de Tubarao by standardization of the technique based on Brazilian and International Standards, manufacturer's recommendations and the experience of the maintenance staff. (author)

  20. Improving Reliability and Durability of Efficient and Clean Energy Systems

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Prabhakar [Univ. of Connecticut, Storrs, CT (United States)

    2010-08-01

    Overall objective of the research program was to develop an in-depth understanding of the degradation processes in advanced electrochemical energy conversion systems. It was also the objective of the research program to transfer the technology to participating industries for implementation in manufacturing of cost effective and reliable integrated systems.

  1. 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

  2. Improvement of the reliability graph with general gates to analyze the reliability of dynamic systems that have various operation modes

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Seung Ki [Div. of Research Reactor System Design, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); No, Young Gyu; Seong, Poong Hyun [Dept. of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2016-04-15

    The safety of nuclear power plants is analyzed by a probabilistic risk assessment, and the fault tree analysis is the most widely used method for a risk assessment with the event tree analysis. One of the well-known disadvantages of the fault tree is that drawing a fault tree for a complex system is a very cumbersome task. Thus, several graphical modeling methods have been proposed for the convenient and intuitive modeling of complex systems. In this paper, the reliability graph with general gates (RGGG) method, one of the intuitive graphical modeling methods based on Bayesian networks, is improved for the reliability analyses of dynamic systems that have various operation modes with time. A reliability matrix is proposed and it is explained how to utilize the reliability matrix in the RGGG for various cases of operation mode changes. The proposed RGGG with a reliability matrix provides a convenient and intuitive modeling of various operation modes of complex systems, and can also be utilized with dynamic nodes that analyze the failure sequences of subcomponents. The combinatorial use of a reliability matrix with dynamic nodes is illustrated through an application to a shutdown cooling system in a nuclear power plant.

  3. Improvement of the reliability graph with general gates to analyze the reliability of dynamic systems that have various operation modes

    International Nuclear Information System (INIS)

    Shin, Seung Ki; No, Young Gyu; Seong, Poong Hyun

    2016-01-01

    The safety of nuclear power plants is analyzed by a probabilistic risk assessment, and the fault tree analysis is the most widely used method for a risk assessment with the event tree analysis. One of the well-known disadvantages of the fault tree is that drawing a fault tree for a complex system is a very cumbersome task. Thus, several graphical modeling methods have been proposed for the convenient and intuitive modeling of complex systems. In this paper, the reliability graph with general gates (RGGG) method, one of the intuitive graphical modeling methods based on Bayesian networks, is improved for the reliability analyses of dynamic systems that have various operation modes with time. A reliability matrix is proposed and it is explained how to utilize the reliability matrix in the RGGG for various cases of operation mode changes. The proposed RGGG with a reliability matrix provides a convenient and intuitive modeling of various operation modes of complex systems, and can also be utilized with dynamic nodes that analyze the failure sequences of subcomponents. The combinatorial use of a reliability matrix with dynamic nodes is illustrated through an application to a shutdown cooling system in a nuclear power plant

  4. Reliability Improved Design for a Safety System Channel

    International Nuclear Information System (INIS)

    Oh, Eung Se; Kim, Yun Goo

    2016-01-01

    Nowadays, these systems are implemented with a same platform type, such as a qualified programmable logic controller (PLC). The platform intensively uses digital communication with fiber-optic links to reduce cabling costs and to achieve effective signal isolation. These communication interface and redundancies within a channel increase the complexness of an overall system design. This paper proposes a simpler channel architecture design to reduce the complexity and to enhance overall channel reliability. Simplified safety channel configuration is proposed and the failure probabilities are compared with baseline safety channel configuration using an estimated generic value. The simplified channel configuration achieves 40 percent failure reduction compare to baseline safety channel configuration. If this configuration can be implemented within a processor module, overall safety channel reliability is increase and costs of fabrication and maintenance will be greatly reduced

  5. Reliability Improved Design for a Safety System Channel

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Eung Se; Kim, Yun Goo [KHNP, Daejeon (Korea, Republic of)

    2016-05-15

    Nowadays, these systems are implemented with a same platform type, such as a qualified programmable logic controller (PLC). The platform intensively uses digital communication with fiber-optic links to reduce cabling costs and to achieve effective signal isolation. These communication interface and redundancies within a channel increase the complexness of an overall system design. This paper proposes a simpler channel architecture design to reduce the complexity and to enhance overall channel reliability. Simplified safety channel configuration is proposed and the failure probabilities are compared with baseline safety channel configuration using an estimated generic value. The simplified channel configuration achieves 40 percent failure reduction compare to baseline safety channel configuration. If this configuration can be implemented within a processor module, overall safety channel reliability is increase and costs of fabrication and maintenance will be greatly reduced.

  6. Equipment reliability process improvement and preventive maintenance optimization

    International Nuclear Information System (INIS)

    Darragi, M.; Georges, A.; Vaillancourt, R.; Komljenovic, D.; Croteau, M.

    2004-01-01

    The Gentilly-2 Nuclear Power Plant wants to optimize its preventive maintenance program through an Integrated Equipment Reliability Process. All equipment reliability related activities should be reviewed and optimized in a systematic approach especially for aging plants such as G2. This new approach has to be founded on best practices methods with the purpose of the rationalization of the preventive maintenance program and the performance monitoring of on-site systems, structures and components (SSC). A rational preventive maintenance strategy is based on optimized task scopes and frequencies depending on their applicability, critical effects on system safety and plant availability as well as cost-effectiveness. Preventive maintenance strategy efficiency is systematically monitored through degradation indicators. (author)

  7. Web server's reliability improvements using recurrent neural networks

    DEFF Research Database (Denmark)

    Madsen, Henrik; Albu, Rǎzvan-Daniel; Felea, Ioan

    2012-01-01

    In this paper we describe an interesting approach to error prediction illustrated by experimental results. The application consists of monitoring the activity for the web servers in order to collect the specific data. Predicting an error with severe consequences for the performance of a server (t...... usage, network usage and memory usage. We collect different data sets from monitoring the web server's activity and for each one we predict the server's reliability with the proposed recurrent neural network. © 2012 Taylor & Francis Group...

  8. Assessment and Improving Methods of Reliability Indices in Bakhtar Regional Electricity Company

    Directory of Open Access Journals (Sweden)

    Saeed Shahrezaei

    2013-04-01

    Full Text Available Reliability of a system is the ability of a system to do prospected duties in future and the probability of desirable operation for doing predetermined duties. Power system elements failures data are the main data of reliability assessment in the network. Determining antiseptic parameters is the goal of reliability assessment by using system history data. These parameters help to recognize week points of the system. In other words, the goal of reliability assessment is operation improving and decreasing of the failures and power outages. This paper is developed to assess reliability indices of Bakhtar Regional Electricity Company up to 1393 and the improving methods and their effects on the reliability indices in this network. DIgSILENT Power Factory software is employed for simulation. Simulation results show the positive effect of improving methods in reliability indices of Bakhtar Regional Electricity Company.

  9. Aviation Fuel System Reliability and Fail-Safety Analysis. Promising Alternative Ways for Improving the Fuel System Reliability

    Directory of Open Access Journals (Sweden)

    I. S. Shumilov

    2017-01-01

    Full Text Available The paper deals with design requirements for an aviation fuel system (AFS, AFS basic design requirements, reliability, and design precautions to avoid AFS failure. Compares the reliability and fail-safety of AFS and aircraft hydraulic system (AHS, considers the promising alternative ways to raise reliability of fuel systems, as well as elaborates recommendations to improve reliability of the pipeline system components and pipeline systems, in general, based on the selection of design solutions.It is extremely advisable to design the AFS and AHS in accordance with Aviation Regulations АП25 and Accident Prevention Guidelines, ICAO (International Civil Aviation Association, which will reduce risk of emergency situations, and in some cases even avoid heavy disasters.ATS and AHS designs should be based on the uniform principles to ensure the highest reliability and safety. However, currently, this principle is not enough kept, and AFS looses in reliability and fail-safety as compared with AHS. When there are the examined failures (single and their combinations the guidelines to ensure the AFS efficiency should be the same as those of norm-adopted in the Regulations АП25 for AHS. This will significantly increase reliability and fail-safety of the fuel systems and aircraft flights, in general, despite a slight increase in AFS mass.The proposed improvements through the use of components redundancy of the fuel system will greatly raise reliability of the fuel system of a passenger aircraft, which will, without serious consequences for the flight, withstand up to 2 failures, its reliability and fail-safety design will be similar to those of the AHS, however, above improvement measures will lead to a slightly increasing total mass of the fuel system.It is advisable to set a second pump on the engine in parallel with the first one. It will run in case the first one fails for some reasons. The second pump, like the first pump, can be driven from the

  10. Improving Stochastic Communication Network Performance: Reliability vs. Throughput

    Science.gov (United States)

    1991-12-01

    increased to one. 2) arc survivabil.. ities will be increased in increments of one tenths. and 3) the costs to increase- arc si’rvivabilities were equal and...This reliability value is leni used to maximize the associated expected flow. For Net work A. a bIdget of (8)() pro(duces a tradcoff point at (.58.37...Network B for a buidgel of 2000 which allows a nel \\\\ork relial)ilitv of one to be achieved and a bidget of 1200 which allows for ;, maximum 57

  11. Reliability improvement of wire bonds subjected to fatigue stresses.

    Science.gov (United States)

    Ravi, K. V.; Philofsky, E. M.

    1972-01-01

    The failure of wire bonds due to repeated flexure when semiconductor devices are operated in an on-off mode has been investigated. An accelerated fatigue testing apparatus was constructed and the major fatigue variables, aluminum alloy composition, and bonding mechanism, were tested. The data showed Al-1% Mg wires to exhibit superior fatigue characteristics compared to Al-1% Cu or Al-1% Si and ultrasonic bonding to be better than thermocompression bonding for fatigue resistance. Based on these results highly reliable devices were fabricated using Al-1% Mg wire with ultrasonic bonding which withstood 120,000 power cycles with no failures.

  12. Modulator reliability and bandwidth improvement: replacing tetrodes with MOSFETs

    International Nuclear Information System (INIS)

    Donaldson, A.R.

    1982-01-01

    Three types of power MOS field effect transistors were studied with the intent of replacing a parallel pair of vacuum tube tetrodes in a linear modulator. The tetrodes have the shortest lifetimes of any other tubes in the system. The FETs offer definite performance advantages when compared to bipolar transistors and definite cost advantages when compared to vacuum tubes. Replacement of the tetrodes does however require careful consideration of voltage, current and to a lesser extent bandwidth capability in order to enhance overall modulator reliability without compromising present performance

  13. Managing the effects of aging and reliability improvement

    International Nuclear Information System (INIS)

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

    1987-01-01

    Over recent years the electric power generating community has acknowledged the importance of the aging process on plant safety and availability. To cope with time-dependent degradation phenomenon that can affect active as well as passive components and lead to unacceptable, unanticipated failures requires research into the mechanisms of the aging process, advances in productive methods for assessing the aging impact on risk and availability, and a better understanding of power plant operations so that strategies for defending against this pervasive stress can be developed. This paper discusses current research advances and presents a framework to aid in the systematic integration of these three needs. As such it is anchored to research being conducted at Brookhaven National Laboratory in the areas of plant aging, life extension, reliability, performance indication, and risk assessment. The current question facing the industry can be simply stated. ''How can an acceptable level of safety and availability be maintained throughout the operational life of a nuclear power plant?'' The complexity of this question indicates that managing aging effects must be a continuous, coordinated process integrated with day-to-day tactical plant operation decisions. This implies that aging and reliability programs must be systemic properties of an organization's management, and that research into aging technology must be closely linked

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

    Directory of Open Access Journals (Sweden)

    B. Mazzorana

    2009-02-01

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

  15. Improving Reliability and Operational Availability of Military Systems

    National Research Council Canada - National Science Library

    Koehn, Phillip

    2004-01-01

    ...: overhaul and prognostics asset management strategies. It is shown that the prognostics approach leads to improved operational availability by anticipating failure and reducing administrative and logistics delays...

  16. Managing the effects of aging and reliability improvement

    International Nuclear Information System (INIS)

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

    1989-01-01

    Over recent years the electric power generating community has acknowledged the importance of the aging process on plant safety and availability. To cope with time-dependent degradation phenomena that can affect active as well as passive components and lead to unacceptable, unanticipated failures requires research into the mechanisms of the aging process, advances in predictive methods for assessing the aging impact on risk and availability, and a better understanding of power plant operations so that strategies for defending against this pervasive stress can be developed. This paper discusses current research advances and presents a framework to aid in the systematic integration of these three needs. It also discusses current research in the aging effect on electric components. As such it is anchored to research being conducted at Brookhaven National Laboratory in the areas of plant aging, life extension, reliability, performance indication, and risk assessment. (orig.)

  17. Managing the effects of aging and reliability improvement

    International Nuclear Information System (INIS)

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

    1988-01-01

    Over recent years the electric power generating community has acknowledged the importance of the aging process on plant safety and availability. To cope with time-dependent degradation phenomena that can affect active as well as passive components and lead to unacceptable, unanticipated failures requires research into the mechanisms of the aging process, advances in predictive methods for assessing the aging impact on risk and availability, and a better understanding of power plant operations so that strategies for defending against this pervasive stress can be developed. This paper discusses current research advances and presents a framework to aid in the systematic integration of these three needs. As such it is anchored to research being conducted at Brookhaven National laboratory in the areas of plant aging, life extension, reliability, performance indication, and risk assessment

  18. Improving the reliability of stator insulation system in rotating machines

    International Nuclear Information System (INIS)

    Gupta, G.K.; Sedding, H.G.; Culbert, I.M.

    1997-01-01

    Reliable performance of rotating machines, especially generators and primary heat transport pump motors, is critical to the efficient operation on nuclear stations. A significant number of premature machine failures have been attributed to the stator insulation problems. Ontario Hydro has attempted to assure the long term reliability of the insulation system in critical rotating machines through proper specifications and quality assurance tests for new machines and periodic on-line and off-line diagnostic tests on machines in service. The experience gained over the last twenty years is presented in this paper. Functional specifications have been developed for the insulation system in critical rotating machines based on engineering considerations and our past experience. These specifications include insulation stress, insulation resistance and polarization index, partial discharge levels, dissipation factor and tip up, AC and DC hipot tests. Voltage endurance tests are specified for groundwall insulation system of full size production coils and bars. For machines with multi-turn coils, turn insulation strength for fast fronted surges in specified and verified through tests on all coils in the factory and on samples of finished coils in the laboratory. Periodic on-line and off-line diagnostic tests were performed to assess the condition of the stator insulation system in machines in service. Partial discharges are measured on-line using several techniques to detect any excessive degradation of the insulation system in critical machines. Novel sensors have been developed and installed in several machines to facilitate measurements of partial discharges on operating machines. Several off-line tests are performed either to confirm the problems indicated by the on-line test or to assess the insulation system in machines which cannot be easily tested on-line. Experience with these tests, including their capabilities and limitations, are presented. (author)

  19. Evaluation and improvement in nondestructive examination (NDE) reliability for inservice inspection of light water reactors

    International Nuclear Information System (INIS)

    Doctor, S.R.; Deffenbaugh, J.D.; Good, M.S.; Green, E.R.; Heasler, P.G.; Simonen, F.A.; Spanner, J.C.; Taylor, T.T.

    1988-01-01

    The Evaluation and Improvement of NDE Reliability for Inservice Inspection of Light Water Reactor (NDE Reliability) program at the Pacific Northwest Laboratory was established by the NRC to determine the reliability of current inservice inspection (ISI) techniques and to develop recommendations that will ensure a suitably high inspection reliability. The objectives of this program include determining the reliability of ISI performed on the primary systems of commercial light-water reactors (LWRs); using probabilistic fracture mechanics analysis to determine the impact of NDE unreliability on system safety; and evaluating reliability improvements that can be achieved with improved and advanced technology. A final objective is to formulate recommended revisions to ASME Code and Regulatory requirements, based on material properties, service conditions, and NDE uncertainties. The program scope is limited to ISI of the primary systems including the piping, vessel, and other inspected components. This is a progress report covering the programmatic work from October 1986 through September 1987

  20. Evaluation and improvement in nondestructive examination (NDE) reliability for inservice inspection of light water reactors

    International Nuclear Information System (INIS)

    Doctor, S.R.; Deffenbaugh, J.D.; Good, M.S.; Green, E.R.; Heasler, P.G.; Simonen, F.A.; Spanner, J.C.; Taylor, T.T.

    1988-01-01

    The Evaluation and Improvement of NDE Reliability for Inservice Inspection of Light Water Reactors (NDE Reliability) program at the Pacific Northwest Laboratory was established by the NRC to determine the reliability of current inservice inspection (ISI) techniques and to develop recommendations that will ensure a suitably high inspection reliability. The objectives of this program include determining the reliability of ISI performed on the primary systems of commercial light-water reactors (LWRs); using probabilistic fracture mechanics analysis to determine the impact of NDE unreliability on system safety; and evaluating reliability improvements that can be achieved with improved and advanced technology. A final objective is to formulate recommended revisions to ASME Code and Regulatory requirements, based on material properties, service conditions and NDE uncertainties. The program scope is limited to ISI of the primary systems including the piping, vessel, and other inspected components. This is a progress report covering the programmatic work from October 1986 through September 1987. (author)

  1. TESTING METHODS FOR MECHANICALLY IMPROVED SOILS: RELIABILITY AND VALIDITY

    Directory of Open Access Journals (Sweden)

    Ana Petkovšek

    2017-10-01

    Full Text Available A possibility of in-situ mechanical improvement for reducing the liquefaction potential of silty sands was investigated by using three different techniques: Vibratory Roller Compaction, Rapid Impact Compaction (RIC and Soil Mixing. Material properties at all test sites were investigated before and after improvement with the laboratory and the in situ tests (CPT, SDMT, DPSH B, static and dynamic load plate test, geohydraulic tests. Correlation between the results obtained by different test methods gave inconclusive answers.

  2. Improving the Reliability of Tinnitus Screening in Laboratory Animals.

    Science.gov (United States)

    Jones, Aikeen; May, Bradford J

    2017-02-01

    Behavioral screening remains a contentious issue for animal studies of tinnitus. Most paradigms base a positive tinnitus test on an animal's natural tendency to respond to the "sound" of tinnitus as if it were an actual sound. As a result, animals with tinnitus are expected to display sound-conditioned behaviors when no sound is present or to miss gaps in background sounds because tinnitus "fills in the gap." Reliable confirmation of the behavioral indications of tinnitus can be problematic because the reinforcement contingencies of conventional discrimination tasks break down an animal's tendency to group tinnitus with sound. When responses in silence are rewarded, animals respond in silence regardless of their tinnitus status. When responses in silence are punished, animals stop responding. This study introduces stimulus classification as an alternative approach to tinnitus screening. Classification procedures train animals to respond to the common perceptual features that define a group of sounds (e.g., high pitch or narrow bandwidth). Our procedure trains animals to drink when they hear tinnitus and to suppress drinking when they hear other sounds. Animals with tinnitus are revealed by their tendency to drink in the presence of unreinforced probe sounds that share the perceptual features of the tinnitus classification. The advantages of this approach are illustrated by taking laboratory rats through a testing sequence that includes classification training, the experimental induction of tinnitus, and postinduction screening. Behavioral indications of tinnitus are interpreted and then verified by simulating a known tinnitus percept with objective sounds.

  3. Improving the reliability of emergency diesel generators through sustained maintenance

    International Nuclear Information System (INIS)

    Reddy, R.

    2000-01-01

    In Nuclear Power Stations Emergency Diesel Generators are vital safety related equipment which ensures power supply to essential equipment during loss of power. In view of their importance Reliability of Diesel generators should be very high. Since these Diesel generators are standby equipment and operate only during demand or during surveillance checks, their demand failure probability should be very low and once they operate their operational availability should be very high. Madras Atomic Power Station at Kalpakkam, India consists two pressurised heavy water Reactors each rated at 220 MWe. To supply standby power each unit has two Diesel Generators of I 500 kW capacity each. The Diesel Engine is 16 cylinder 'V' type engine and is cranked by Air starting motor and is connected to generator whose rating at 100% load is 1500 KW. During commissioning and in the initial years of operation these Diesel Generators have encountered many problems. Major problem was Diesel Engine failing to start on demand. This was due to non engagement of air motor pinion with ring gear or continued engagement air motor even after the engine had picked up speed and failure of timer to initiate multiple starts after initial incomplete starts Apart from these there were problems like fuel oil leaks, high jacket water temperatures, low fuel oil pressure trips. Another major problem was with excitation system. How these problems were dealt with thereby reducing the demand failure probability and increasing the operational availability are discussed in this paper. (author)

  4. Improving Punctuality and Transfer Reliability by Railway Timetable Optimization

    NARCIS (Netherlands)

    Goverde, R.M.P.

    1999-01-01

    The Dutch railway network is operated close to capacity with the current safety system. This leaves little space for control by process operators by which a delayed train can cause severe delay propagation. The NS currently invest a large amount in punctuality improvement of the railway operations.

  5. Advanced surface protection for improved reliability PCB systems (ASPIS)

    NARCIS (Netherlands)

    Ballantyne, A.; Forrest, G.; Goosey, M.; Griguceviciene, A.; Juodkazyte, J.; Kellner, R.; Kosenko, A.; Ramanauskas, R.; Ryder, K.; Selskis, A.; Tarozaite, R.; Veninga, E.

    2012-01-01

    Purpose - The purpose of this paper is to detail progress on the European Commission supported FP7 ASPIS project that is undertaking a multi-faceted approach to develop novel and improved nickel-gold (ENIG) solderable finish chemistries and processes in order to overcome issues such as "black pad"

  6. Legal Effect of Breach of Warranty in Construction Insurance in Malaysia

    OpenAIRE

    Arazi Idrus; Mahmoud Sodangi; Jamaluddin Yaakob

    2011-01-01

    This study is aimed at analyzing the legal effect of breach of warranty in construction insurance contracts in Malaysia in light of the current developments in The English insurance law. The required data and information were collected from Malaysian and English court decisions dealing with breach of warranties in English marine insurance law from the online Malayan Law Journal published on the LexisNexis online database and from published textbooks related to insurance warranties. This study...

  7. Warranty of Misinforming as an Option in Product Utilization Process

    Directory of Open Access Journals (Sweden)

    Dimitar Grozdanov Christozov

    2016-05-01

    Full Text Available The following definition of “option” is given in Wikipedia - “In finance, an option is a contract, which gives the buyer (the owner or holder the right, but not the obligation, to buy or sell an underlying asset or instrument at a specified strike price on or before a specified date, depending on the form of the option” (“Option,” n.d.. Option as a risk management (mitigation tool is broadly used in finance and trade. At the same time, it introduces asymmetry in the sense that, probabilistically, it limits the level of losses (e.g., the price of the option and allows for unlimited gains. In the market of sophisticated devices (as smart phones, tablets, etc., where technologies are rapidly advancing, customers usually do not have the experience to use all features of the device at the time of the purchase. Due to the lack of appropriate expertise, the risk of misinforming, leading to not purchasing the “right” device is high, but given enough time to learn the capabilities of the device and map these to the needs and tasks that device will be used for, could provide the client with substantial long term benefits. Warranty of misinforming is a mechanism that provides the client with the opportunity to explore the device and master its features under limited risk of financial losses. Thus, the warranty of misinforming could be considered as an option - the custom-ers buy it (at a fixed cost and may gain (theoretically unlimited benefit by realizing (within the terms of the warranty that the device can be used to solve a variety of problems not envisaged at the time of purchase. In this study we present the idea of treating the warranty of misinforming as an option in finances and provide examples to illustrate our viewpoint.

  8. A two-stage preventive maintenance optimization model incorporating two-dimensional extended warranty

    International Nuclear Information System (INIS)

    Su, Chun; Wang, Xiaolin

    2016-01-01

    In practice, customers can decide whether to buy an extended warranty or not, at the time of item sale or at the end of the basic warranty. In this paper, by taking into account the moments of customers purchasing two-dimensional extended warranty, the optimization of imperfect preventive maintenance for repairable items is investigated from the manufacturer's perspective. A two-dimensional preventive maintenance strategy is proposed, under which the item is preventively maintained according to a specified age interval or usage interval, whichever occurs first. It is highlighted that when the extended warranty is purchased upon the expiration of the basic warranty, the manufacturer faces a two-stage preventive maintenance optimization problem. Moreover, in the second stage, the possibility of reducing the servicing cost over the extended warranty period is explored by classifying customers on the basis of their usage rates and then providing them with customized preventive maintenance programs. Numerical examples show that offering customized preventive maintenance programs can reduce the manufacturer's warranty cost, while a larger saving in warranty cost comes from encouraging customers to buy the extended warranty at the time of item sale. - Highlights: • A two-dimensional PM strategy is investigated. • Imperfect PM strategy is optimized by considering both two-dimensional BW and EW. • Customers are categorized based on their usage rates throughout the BW period. • Servicing cost of the EW is reduced by offering customized PM programs. • Customers buying the EW at the time of sale is preferred for the manufacturer.

  9. Cost analysis of two-dimensional warranty for products with periodic preventive maintenance

    International Nuclear Information System (INIS)

    Huang, Yeu-Shiang; Gau, Wei-Yo; Ho, Jyh-Wen

    2015-01-01

    This study uses a bivariate approach, which simultaneously considers the time and usage of a repairable product, and takes into account periodic preventive maintenance to develop a two-dimensional warranty policy for the repairable product. The proposed model is based on the bivariate Weibull process to analyze the breakdown process of a repairable product simultaneously in terms of time and usage. A repairable product may be differently utilized by various customers. We consider two types of customers: (1) customers whose product warranty is terminated because the warranty time limit has reached first; (2) customers whose product warranty is terminated because the warranty usage limit has reached first, to perform cost analyses for determining an appropriate warranty policy. However, since it is often the case that the repairable product may be equally likely purchased by the two types of customers who are equivalently important to the product manufacturer; the optimal warranty policy would thus be the equilibrium solution of the cost analyses which pay the same attention to both types of customers in order to maximize the total profit of the manufacturer. - Highlights: • We use a bivariate method to model the breakdown process. • We consider a periodic PM schedule. • We obtain an optimal two-dimensional warranty policy considering various customers. • The optimal 2D warranty is an equilibrium which satisfies both seller and buyer

  10. Reliability improvement: where do we go from here. The role of codes and standards

    International Nuclear Information System (INIS)

    Davidson, R.H.

    1976-01-01

    The role of codes and standards in contributing to the future improvement is discussed. The Nuclear Plant Reliability Data System is examined. It is suggested that two systems of the type are needed. One system should focus on component and system reliability while the other should focus on system availability, capacity factor, and fixed outage rate assessment

  11. Training Improves Interobserver Reliability for the Diagnosis of Scaphoid Fracture Displacement

    NARCIS (Netherlands)

    Buijze, Geert A.; Guitton, Thierry G.; van Dijk, C. Niek; Ring, David; Osterman, A. Lee; Wahegaonkar, Abhijeet L.; Ladd, Amy; Barquet, Antonio; van Vugt, Arie B.; Shyam, Ashok K.; Swigart, Carrie; Coles, Chad P.; Zalavras, Charalampos; Goldfarb, Charles A.; Cassidy, Charles; Allan, Christopher; Beingessner, Daphne; Kalainov, David M.; Eygendaal, Denise; Sancheti, Parag; Feibel, Robert J.; Rocha, Steve; Grosso, Elena; Frihagen, Frede; Dyer, George S. M.; Athwal, George S.; Goslings, J. Carel; Della Rocca, Gregory J.; Harris, Ian; Fanuele, Jason C.; Lawton, Jeff; Jiuliano, John; McAuliffe, John; Capo, John T.; Conflitti, Joseph M.; Segalman, Keith; Egol, Kenneth; Ponsen, Kornelis J.; Jeray, Kyle; Lattanza, Lisa; Catalano, Louis; Swiontkowski, Marc; Boyer, Martin; Richardson, Martin; Soong, Maximillian; Baskies, Michael; Prayson, Michael; McKee, Michael; Chen, Neal C.; Kloen, Peter

    2012-01-01

    The diagnosis of displacement in scaphoid fractures is notorious for poor interobserver reliability. We tested whether training can improve interobserver reliability and sensitivity, specificity, and accuracy for the diagnosis of scaphoid fracture displacement on radiographs and CT scans. Sixty-four

  12. 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)

  13. Improving QST Reliability – More Raters, Tests or Occasions? A Multivariate Generalizability Study

    DEFF Research Database (Denmark)

    O'Neill, Søren; O'Neill, Lotte

    2015-01-01

    The reliability of quantitative sensory testing (QST) is affected by the error attributable to both test occasion and rater (examiner) as well as interactions between them. Most reliability studies only account for one source of error. The present study employed a fully-crossed, multivariate...... threshold, intensity, tolerance and modulation with mechanical, thermal and chemical stimuli. The classical test-retest and inter-rater reliability (0.19... procedures. Reliability was improved more by repeated testing on separate occasions opposed to repeated testing by different raters....

  14. Improved Yield, Performance and Reliability of High-Actuator-Count Deformable Mirrors, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The project team will conduct processing and design research aimed at improving yield, performance, and reliability of high-actuator-count micro-electro-mechanical...

  15. Reliability Improvement of Power Converters by Means of Condition Monitoring of IGBT Modules

    DEFF Research Database (Denmark)

    Choi, Ui Min; Blaabjerg, Frede; Jørgensen, S.

    2017-01-01

    Power electronic systems have gradually gained an important status in a wide range of industrial applications such as renewable generation, motor drives, automotive, and railway transportation. Accordingly, recent research makes an effort to improve the reliability of power electronic systems...

  16. Reliability Evaluation and Improvement Approach of Chemical Production Man - Machine - Environment System

    Science.gov (United States)

    Miao, Yongchun; Kang, Rongxue; Chen, Xuefeng

    2017-12-01

    In recent years, with the gradual extension of reliability research, the study of production system reliability has become the hot topic in various industries. Man-machine-environment system is a complex system composed of human factors, machinery equipment and environment. The reliability of individual factor must be analyzed in order to gradually transit to the research of three-factor reliability. Meanwhile, the dynamic relationship among man-machine-environment should be considered to establish an effective blurry evaluation mechanism to truly and effectively analyze the reliability of such systems. In this paper, based on the system engineering, fuzzy theory, reliability theory, human error, environmental impact and machinery equipment failure theory, the reliabilities of human factor, machinery equipment and environment of some chemical production system were studied by the method of fuzzy evaluation. At last, the reliability of man-machine-environment system was calculated to obtain the weighted result, which indicated that the reliability value of this chemical production system was 86.29. Through the given evaluation domain it can be seen that the reliability of man-machine-environment integrated system is in a good status, and the effective measures for further improvement were proposed according to the fuzzy calculation results.

  17. The Reliability of In-Training Assessment when Performance Improvement Is Taken into Account

    Science.gov (United States)

    van Lohuizen, Mirjam T.; Kuks, Jan B. M.; van Hell, Elisabeth A.; Raat, A. N.; Stewart, Roy E.; Cohen-Schotanus, Janke

    2010-01-01

    During in-training assessment students are frequently assessed over a longer period of time and therefore it can be expected that their performance will improve. We studied whether there really is a measurable performance improvement when students are assessed over an extended period of time and how this improvement affects the reliability of the…

  18. Evaluation and improvement of nondestructive evaluation reliability for inservice inspection of light water reactors

    International Nuclear Information System (INIS)

    Bates, D.J.; Deffenbaugh, J.D.; Good, M.S.; Heasler, P.G.; Mart, G.A.; Simonen, F.A.; Spanner, J.C.; Taylor, T.T.; Van Fleet, L.G.

    1987-01-01

    The Evaluation and Improvement of NDE Reliability for Inservice Inspection (ISI) of Light Water Reactors (NDE Reliability) Program at Pacific Northwest Laboratory (PNL) was established to determine the reliability of current ISI techniques and to develop recommendations that will ensure a suitably high inspection reliability. The objectives of this NRC program are to: determine the reliability of ultrasonic ISI performed on commercial light-water reactor (LWR) primary systems, using probabilistic fracture mechanics analysis, determine the impact of NDE unreliability on system safety and determine the level of inspection reliability required to ensure a suitably low failure probability, evaluate the degree of reliability improvement that could be achieved using improved and advanced NDE techniques, based on material properties, service conditions, and NDE uncertainties, recommend revisions to ASME Code, Section XI, and Regulatory Requirements that will ensure suitably low failure probabilities. The scope of this program is limited to ISI of primary systems; the results and recommendations may also be applicable to Class II piping systems

  19. 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.

  20. Optimal post-warranty maintenance policy with repair time threshold for minimal repair

    International Nuclear Information System (INIS)

    Park, Minjae; Mun Jung, Ki; Park, Dong Ho

    2013-01-01

    In this paper, we consider a renewable minimal repair–replacement warranty policy and propose an optimal maintenance model after the warranty is expired. Such model adopts the repair time threshold during the warranty period and follows with a certain type of system maintenance policy during the post-warranty period. As for the criteria for optimality, we utilize the expected cost rate per unit time during the life cycle of the system, which has been frequently used in many existing maintenance models. Based on the cost structure defined for each failure of the system, we formulate the expected cost rate during the life cycle of the system, assuming that a renewable minimal repair–replacement warranty policy with the repair time threshold is provided to the user during the warranty period. Once the warranty is expired, the maintenance of the system is the user's sole responsibility. The life cycle of the system is defined on the perspective of the user and the expected cost rate per unit time is derived in this context. We obtain the optimal maintenance policy during the maintenance period following the expiration of the warranty period by minimizing such a cost rate. Numerical examples using actual failure data are presented to exemplify the applicability of the methodologies proposed in this paper.

  1. 48 CFR 46.707 - Pricing aspects of fixed-price incentive contract warranties.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Pricing aspects of fixed-price incentive contract warranties. 46.707 Section 46.707 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION CONTRACT MANAGEMENT QUALITY ASSURANCE Warranties 46.707 Pricing aspects of...

  2. 48 CFR 52.246-17 - Warranty of Supplies of a Noncomplex Nature.

    Science.gov (United States)

    2010-10-01

    ... Noncomplex Nature. 52.246-17 Section 52.246-17 Federal Acquisition Regulations System FEDERAL ACQUISITION... Clauses 52.246-17 Warranty of Supplies of a Noncomplex Nature. As prescribed in 46.710(a)(1), insert a clause substantially as follows: Warranty of Supplies of a Noncomplex Nature (JUN 2003) (a) Definitions...

  3. 48 CFR 52.246-18 - Warranty of Supplies of a Complex Nature.

    Science.gov (United States)

    2010-10-01

    ... Complex Nature. 52.246-18 Section 52.246-18 Federal Acquisition Regulations System FEDERAL ACQUISITION... Clauses 52.246-18 Warranty of Supplies of a Complex Nature. As prescribed in 46.710(b)(1), insert a clause substantially as follows: Warranty of Supplies of a Complex Nature (MAY 2001) (a) Definitions. As used in this...

  4. 48 CFR 552.246-77 - Additional Contract Warranty Provisions for Supplies of a Noncomplex Nature.

    Science.gov (United States)

    2010-10-01

    ... Warranty Provisions for Supplies of a Noncomplex Nature. 552.246-77 Section 552.246-77 Federal Acquisition... a Noncomplex Nature. As prescribed in 546.710(a), insert the following clause in solicitations and contracts that include FAR 52.246-17, Warranty of Supplies of a Noncomplex Nature. Additional Contract...

  5. Features of the Organization of Accounting and Tax Accounting and Auditing at Warranty Repairs

    Directory of Open Access Journals (Sweden)

    Mardus Nataliia Yu.

    2016-08-01

    Full Text Available The aim of the article is to study features of the normative and legal support of accounting and tax accounting at providing operations with warranty repairs comprising the secured in legislation right of consumers to obtain from the companies-producers (sellers products (goods and services of proper quality and cases of occurrence of warranty obligations to customers. To achieve the goal, the following tasks have been solved: the regulatory framework for the organization of warranty service (repair from the point of view of the company-seller and reflection of operations associated with warranty repairs in accounting and tax accounting was studied. The article describes the features of the organization of accounting and tax accounting at warranty repairs based on the legislative and normative documents regulating relations that arise in the organization and implementation of economic activity between business entities and between the entities and other participants of relations in the sphere of economic activity.

  6. Reliability improvement in GaN HEMT power device using a field plate approach

    Science.gov (United States)

    Wu, Wen-Hao; Lin, Yueh-Chin; Chin, Ping-Chieh; Hsu, Chia-Chieh; Lee, Jin-Hwa; Liu, Shih-Chien; Maa, Jer-shen; Iwai, Hiroshi; Chang, Edward Yi; Hsu, Heng-Tung

    2017-07-01

    This study investigates the effect of implementing a field plate on a GaN high-electron-mobility transistor (HEMT) to improve power device reliability. The results indicate that the field plate structure reduces the peak electrical field and interface traps in the device, resulting in higher breakdown voltage, lower leakage current, smaller current collapse, and better threshold voltage control. Furthermore, after high voltage stress, steady dynamic on-resistance and gate capacitance degradation improvement were observed for the device with the field plate. This demonstrates that GaN device reliability can be improved by using the field plate approach.

  7. Reliability improvements on Thales RM2 rotary Stirling coolers: analysis and methodology

    Science.gov (United States)

    Cauquil, J. M.; Seguineau, C.; Martin, J.-Y.; Benschop, T.

    2016-05-01

    The cooled IR detectors are used in a wide range of applications. Most of the time, the cryocoolers are one of the components dimensioning the lifetime of the system. The cooler reliability is thus one of its most important parameters. This parameter has to increase to answer market needs. To do this, the data for identifying the weakest element determining cooler reliability has to be collected. Yet, data collection based on field are hardly usable due to lack of informations. A method for identifying the improvement in reliability has then to be set up which can be used even without field return. This paper will describe the method followed by Thales Cryogénie SAS to reach such a result. First, a database was built from extensive expertizes of RM2 failures occurring in accelerate ageing. Failure modes have then been identified and corrective actions achieved. Besides this, a hierarchical organization of the functions of the cooler has been done with regard to the potential increase of its efficiency. Specific changes have been introduced on the functions most likely to impact efficiency. The link between efficiency and reliability will be described in this paper. The work on the two axes - weak spots for cooler reliability and efficiency - permitted us to increase in a drastic way the MTTF of the RM2 cooler. Huge improvements in RM2 reliability are actually proven by both field return and reliability monitoring. These figures will be discussed in the paper.

  8. ANALYSIS OF POWER SYSTEM RELIABILITY IMPROVEMENT FOR 74-BUS RADIAL DISTRIBUTION SYSTEM

    OpenAIRE

    Su Mon Myint*

    2018-01-01

    In Myanmar, electric power system planning is widely constructed because of more and more load growth and facing with failure of electricity, outage problems and system shut-down. Thus, not only making new power system network but also improving reliability of the existing system using suitable methods is very important to provide an adequate supply of electrical energy to its customers as economically and reliably as possible with an acceptable degree of continuity and quality that is design...

  9. Improving patient safety: patient-focused, high-reliability team training.

    Science.gov (United States)

    McKeon, Leslie M; Cunningham, Patricia D; Oswaks, Jill S Detty

    2009-01-01

    Healthcare systems are recognizing "human factor" flaws that result in adverse outcomes. Nurses work around system failures, although increasing healthcare complexity makes this harder to do without risk of error. Aviation and military organizations achieve ultrasafe outcomes through high-reliability practice. We describe how reliability principles were used to teach nurses to improve patient safety at the front line of care. Outcomes include safety-oriented, teamwork communication competency; reflections on safety culture and clinical leadership are discussed.

  10. Equipment reliability improvement process; implementation in Almaraz NPP and Trillo NPP

    International Nuclear Information System (INIS)

    Risquez Bailon, Aranzazu; Gutierrez Fernandez, Eduardo

    2010-01-01

    The Equipment Reliability Improvement Process (INPO AP-913) is a non-regulatory process developed by the US Nuclear Industry for improving Plants Availability. This Process integrates and coordinates a broad range of equipment reliability activities into one process, performed by the Plant in a non-centralized way. The integration and coordination of these activities will allow plant personnel to evaluate the trends of important station equipment, develop and implement long-term equipment health plans, monitor equipment performance and condition, and make adjustments to preventive maintenance tasks and frequencies based on equipment operating experience, if necessary, arbitrating operational and design improvements, to reach a Failure-free Operation. This paper describes the methodology of Equipment Reliability Improvement Process, being focused on main aspects of the implementation process, relating to the scope and establishment of an Equipment Reliability Monitoring Plan, which should include and complement the existing mechanisms and organizations in the Plant to monitor the condition and performance of the equipments, with the common aim of achieving an operation free of failures. The paper will describe the tools that Iberdrola Ingenieria has developed to support the implementation and monitoring of the Equipment Reliability Improvement Process, as well as the results and lessons learned from its implementation in Almaraz NPP and Trillo NPP. (authors)

  11. Device Performance and Reliability Improvements of AlGaBN/GaN/Si MOSFET

    Science.gov (United States)

    2016-02-04

    AFRL-AFOSR-JP-TR-2016-0037 Device Performance and Reliablity Improvements of AlGaBN/GaN/Si MOSFET Robert Wallace UNIVERSITY OF TEXAS AT DALLAS Final...GaN/Si MOSFET 5a.  CONTRACT NUMBER 5b.  GRANT NUMBER FA2386-14-1-4069 5c.  PROGRAM ELEMENT NUMBER 61102F 6. AUTHOR(S) Robert Wallace 5d.  PROJECT...AOARD Grant FA2386-14-1-4069 Device Performance and Reliability Improvements of AlGaN/GaN/Si MOSFET US 12 month extension (2014 – 2015) for current

  12. Improving the reliability of fuel Enusa; Mejora de la fiabilidad del combustible en Enusa

    Energy Technology Data Exchange (ETDEWEB)

    Choithramani, S.; Quecedo, M.

    2015-07-01

    ENUSA is committed to providing our customers with fuel designs that meet their needs for operational efficiency, power, energy, performance and reliability. ENUSAs current fuel designs, covering BWR and PWR technologies, incorporate highest performance with proven reliability features developed along nuclear power operation history. As of January 2015, ENUSA has manufactured more than 20.000 fuel assemblies (around half BWR and half PWR), with operating conditions reflecting varying reactor power densities, cycle lengths, operating strategies and water chemistry environments. This experience brings the knowledge to model our fuel behavior and acts as the principal instrument to identify and characterize the failure mechanisms of our fuel. Based on the information obtained from all this years of operation, ENUSA has progressively developed and implemented numerous mitigating actions identified upon the knowledge on failure mechanisms, which are the bases for the fuel reliability improvement program. Contemporaneously to this implementation, a positive trend on ENUSA fuel reliability has been observed. (Author)

  13. Promoting seismic retrofit implementation through "nudge": using warranty as a driver.

    Science.gov (United States)

    Fujimi, Toshio; Tatano, Hirokazu

    2013-10-01

    This article proposes a new type of warranty policy that applies the "nudge" concept developed by Thaler and Sunstein to encourage homeowners in Japan to implement seismic retrofitting. Homeowner adaptation to natural disasters through loss reduction measures is known to be inadequate. To encourage proactive risk management, the "nudge" approach capitalizes on how choice architecture can influence human decision-making tendencies. For example, people tend to place more value on a warranty for consumer goods than on actuarial value. This article proposes a "warranty for seismic retrofitting" as a "nudge" policy that gives homeowners the incentive to adopt loss reduction measures. Under such a contract, the government guarantees all repair costs in the event of earthquake damage to the house if the homeowner implements seismic retrofitting. To estimate the degree to which a warranty will increase the perceived value of seismic retrofitting, we use field survey data from 1,200 homeowners. Our results show that a warranty increases the perceived value of seismic retrofitting by an average of 33%, and an approximate cost-benefit analysis indicates that such a warranty can be more economically efficient than an ex ante subsidy. Furthermore, we address the failure of the standard expected utility model to explain homeowners' decisions based on warranty evaluation, and explore the significant influence of ambiguity aversion on the efficacy of seismic retrofitting and nonanalytical factors such as feelings or trust. © 2013 Society for Risk Analysis.

  14. Cost/worth assessment of reliability improvement in distribution networks by means of artificial intelligence

    Energy Technology Data Exchange (ETDEWEB)

    Bouhouras, Aggelos S.; Labridis, Dimitris P.; Bakirtzis, Anastasios G. [Power Systems Laboratory, Aristotle University of Thessaloniki, Dept. of Electrical and Computer Engineering, 54124 Thessaloniki (Greece)

    2010-06-15

    A major challenge for the power utilities today is to ensure a high level of reliability of supply to customers. Two main factors determine the feasibility of a project that improves the reliability of supply: the project cost (investment and operational) and the benefits that result from the implementation of the project. This paper examines the implementation of an Artificial Intelligence System in an urban distribution network, capable to locate and isolate short circuit faults in the feeder, thus accomplishing immediate restoration of electric supply to the customers. The paper describes the benefits of the project, which are supply reliability improvement and distribution network loss reduction through network reconfigurations. By comparison of the project benefits and costs the economic feasibility of such a project for an underground distribution feeder in Greece is demonstrated. (author)

  15. Advancements in valve technology and industry lessons lead to improved plant reliability and cost savings

    International Nuclear Information System (INIS)

    Sharma, V.; Kalsi, M.S.

    2005-01-01

    Plant reliability and safety hinges on the proper functioning of several valves. Recent advancements in valve technology have resulted in new analytical and test methods for evaluating and improving valve and actuator reliability. This is especially significant in critical service applications in which the economic impact of a valve failure on production, outage schedules and consequential damages far surpasses the initial equipment purchase price. This paper presents an overview of recent advances in valve technology driven by reliability concerns and cost savings objectives without comprising safety in the Nuclear Power Industry. This overview is based on over 27 years of experience in supporting US and International nuclear power utilities, and contributing to EPRI, and NSSS Owners' Groups in developing generic models/methodologies to address industry wide issues; performing design basis reviews; and implementing plant-wide valve reliability improvement programs. Various analytical prediction software and hardware solutions and training seminars are now available to implement valve programs covering power plants' lifecycle from the construction phase through life extension and power up rate. These tools and methodologies can enhance valve-engineering activities including the selection, sizing, proper application, condition monitoring, failure analysis, and condition based maintenance optimization with a focus on potential bad actors. This paper offers two such examples, the Kalsi Valve and Actuator Program (KVAP) and Check Valve Analysis and Prioritization (CVAP) [1-3, 8, 9, 11-13]. The advanced, validated torque prediction models incorporated into KVAP software for AOVs and MOVs have improved reliability of margin predictions and enabled cost savings through elimination of unwarranted equipment modifications. CVAP models provides a basis to prioritize the population of valves recommended for preventive maintenance, inspection and/or modification, allowing

  16. 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 ...

  17. Precision of lumbar intervertebral measurements: does a computer-assisted technique improve reliability?

    Science.gov (United States)

    Pearson, Adam M; Spratt, Kevin F; Genuario, James; McGough, William; Kosman, Katherine; Lurie, Jon; Sengupta, Dilip K

    2011-04-01

    Comparison of intra- and interobserver reliability of digitized manual and computer-assisted intervertebral motion measurements and classification of "instability." To determine if computer-assisted measurement of lumbar intervertebral motion on flexion-extension radiographs improves reliability compared with digitized manual measurements. Many studies have questioned the reliability of manual intervertebral measurements, although few have compared the reliability of computer-assisted and manual measurements on lumbar flexion-extension radiographs. Intervertebral rotation, anterior-posterior (AP) translation, and change in anterior and posterior disc height were measured with a digitized manual technique by three physicians and by three other observers using computer-assisted quantitative motion analysis (QMA) software. Each observer measured 30 sets of digital flexion-extension radiographs (L1-S1) twice. Shrout-Fleiss intraclass correlation coefficients for intra- and interobserver reliabilities were computed. The stability of each level was also classified (instability defined as >4 mm AP translation or 10° rotation), and the intra- and interobserver reliabilities of the two methods were compared using adjusted percent agreement (APA). Intraobserver reliability intraclass correlation coefficients were substantially higher for the QMA technique THAN the digitized manual technique across all measurements: rotation 0.997 versus 0.870, AP translation 0.959 versus 0.557, change in anterior disc height 0.962 versus 0.770, and change in posterior disc height 0.951 versus 0.283. The same pattern was observed for interobserver reliability (rotation 0.962 vs. 0.693, AP translation 0.862 vs. 0.151, change in anterior disc height 0.862 vs. 0.373, and change in posterior disc height 0.730 vs. 0.300). The QMA technique was also more reliable for the classification of "instability." Intraobserver APAs ranged from 87 to 97% for QMA versus 60% to 73% for digitized manual

  18. Improving fMRI reliability in presurgical mapping for brain tumours.

    Science.gov (United States)

    Stevens, M Tynan R; Clarke, David B; Stroink, Gerhard; Beyea, Steven D; D'Arcy, Ryan Cn

    2016-03-01

    Functional MRI (fMRI) is becoming increasingly integrated into clinical practice for presurgical mapping. Current efforts are focused on validating data quality, with reliability being a major factor. In this paper, we demonstrate the utility of a recently developed approach that uses receiver operating characteristic-reliability (ROC-r) to: (1) identify reliable versus unreliable data sets; (2) automatically select processing options to enhance data quality; and (3) automatically select individualised thresholds for activation maps. Presurgical fMRI was conducted in 16 patients undergoing surgical treatment for brain tumours. Within-session test-retest fMRI was conducted, and ROC-reliability of the patient group was compared to a previous healthy control cohort. Individually optimised preprocessing pipelines were determined to improve reliability. Spatial correspondence was assessed by comparing the fMRI results to intraoperative cortical stimulation mapping, in terms of the distance to the nearest active fMRI voxel. The average ROC-r reliability for the patients was 0.58±0.03, as compared to 0.72±0.02 in healthy controls. For the patient group, this increased significantly to 0.65±0.02 by adopting optimised preprocessing pipelines. Co-localisation of the fMRI maps with cortical stimulation was significantly better for more reliable versus less reliable data sets (8.3±0.9 vs 29±3 mm, respectively). We demonstrated ROC-r analysis for identifying reliable fMRI data sets, choosing optimal postprocessing pipelines, and selecting patient-specific thresholds. Data sets with higher reliability also showed closer spatial correspondence to cortical stimulation. ROC-r can thus identify poor fMRI data at time of scanning, allowing for repeat scans when necessary. ROC-r analysis provides optimised and automated fMRI processing for improved presurgical mapping. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence

  19. Training less-experienced faculty improves reliability of skills assessment in cardiac surgery.

    Science.gov (United States)

    Lou, Xiaoying; Lee, Richard; Feins, Richard H; Enter, Daniel; Hicks, George L; Verrier, Edward D; Fann, James I

    2014-12-01

    Previous work has demonstrated high inter-rater reliability in the objective assessment of simulated anastomoses among experienced educators. We evaluated the inter-rater reliability of less-experienced educators and the impact of focused training with a video-embedded coronary anastomosis assessment tool. Nine less-experienced cardiothoracic surgery faculty members from different institutions evaluated 2 videos of simulated coronary anastomoses (1 by a medical student and 1 by a resident) at the Thoracic Surgery Directors Association Boot Camp. They then underwent a 30-minute training session using an assessment tool with embedded videos to anchor rating scores for 10 components of coronary artery anastomosis. Afterward, they evaluated 2 videos of a different student and resident performing the task. Components were scored on a 1 to 5 Likert scale, yielding an average composite score. Inter-rater reliabilities of component and composite scores were assessed using intraclass correlation coefficients (ICCs) and overall pass/fail ratings with kappa. All components of the assessment tool exhibited improvement in reliability, with 4 (bite, needle holder use, needle angles, and hand mechanics) improving the most from poor (ICC range, 0.09-0.48) to strong (ICC range, 0.80-0.90) agreement. After training, inter-rater reliabilities for composite scores improved from moderate (ICC, 0.76) to strong (ICC, 0.90) agreement, and for overall pass/fail ratings, from poor (kappa = 0.20) to moderate (kappa = 0.78) agreement. Focused, video-based anchor training facilitates greater inter-rater reliability in the objective assessment of simulated coronary anastomoses. Among raters with less teaching experience, such training may be needed before objective evaluation of technical skills. Published by Elsevier Inc.

  20. Technology Improvement for the High Reliability LM-2F Launch Vehicle

    Institute of Scientific and Technical Information of China (English)

    QIN Tong; RONG Yi; ZHENG Liwei; ZHANG Zhi

    2017-01-01

    The Long March 2F (LM-2F) launch vehicle,the only launch vehicle designed for manned space flight in China,successfully launched the Tiangong 2 space laboratory and the Shenzhou ll manned spaceship into orbits in 2016 respectively.In this study,it introduces the technological improvements for enhancing the reliability of the LM-2F launch vehicle in the aspects of general technology,control system,manufacture and ground support system.The LM2F launch vehicle will continue to provide more contributions to the Chinese Space Station Project with its high reliability and 100% success rate.

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

    Science.gov (United States)

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

    2018-01-01

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

  2. Embedded Sensors and Controls to Improve Component Performance and Reliability Conceptual Design Report

    Energy Technology Data Exchange (ETDEWEB)

    Kisner, R.; Melin, A.; Burress, T.; Fugate, D.; Holcomb, D.; Wilgen, J.; Miller, J.; Wilson, D.; Silva, P.; Whitlow, L.; Peretz, F.

    2012-09-15

    The objective of this project is to demonstrate improved reliability and increased performance made possible by deeply embedding instrumentation and controls (I&C) in nuclear power plant (NPP) components and systems. The project is employing a highly instrumented canned rotor, magnetic bearing, fluoride salt pump as its I&C technology demonstration platform. I&C is intimately part of the basic millisecond-by-millisecond functioning of the system; treating I&C as an integral part of the system design is innovative and will allow significant improvement in capabilities and performance. As systems become more complex and greater performance is required, traditional I&C design techniques become inadequate and more advanced I&C needs to be applied. New I&C techniques enable optimal and reliable performance and tolerance of noise and uncertainties in the system rather than merely monitoring quasistable performance. Traditionally, I&C has been incorporated in NPP components after the design is nearly complete; adequate performance was obtained through over-design. By incorporating I&C at the beginning of the design phase, the control system can provide superior performance and reliability and enable designs that are otherwise impossible. This report describes the progress and status of the project and provides a conceptual design overview for the platform to demonstrate the performance and reliability improvements enabled by advanced embedded I&C.

  3. Evaluation of Smart Grid Technologies Employed for System Reliability Improvement: Pacific Northwest Smart Grid Demonstration Experience

    Energy Technology Data Exchange (ETDEWEB)

    Agalgaonkar, Yashodhan P.; Hammerstrom, Donald J.

    2017-06-01

    The Pacific Northwest Smart Grid Demonstration (PNWSGD) was a smart grid technology performance evaluation project that included multiple U.S. states and cooperation from multiple electric utilities in the northwest region. One of the local objectives for the project was to achieve improved distribution system reliability. Toward this end, some PNWSGD utilities automated their distribution systems, including the application of fault detection, isolation, and restoration and advanced metering infrastructure. In light of this investment, a major challenge was to establish a correlation between implementation of these smart grid technologies and actual improvements of distribution system reliability. This paper proposes using Welch’s t-test to objectively determine and quantify whether distribution system reliability is improving over time. The proposed methodology is generic, and it can be implemented by any utility after calculation of the standard reliability indices. The effectiveness of the proposed hypothesis testing approach is demonstrated through comprehensive practical results. It is believed that wider adoption of the proposed approach can help utilities to evaluate a realistic long-term performance of smart grid technologies.

  4. Improving the reliability of nuclear reprocessing by application of computers and mathematical modelling

    International Nuclear Information System (INIS)

    Gabowitsch, E.; Trauboth, H.

    1982-01-01

    After a brief survey of the present and expected future state of nuclear energy utilization, which should demonstrate the significance of nuclear reprocessing, safety and reliability aspects of nuclear reprocessing plants (NRP) are considered. Then, the principal possibilities of modern computer technology including computer systems architecture and application-oriented software for improving the reliability and availability are outlined. In this context, two information systems being developed at the Nuclear Research Center Karlsruhe (KfK) are briefly described. For design evaluation of certain areas of a large NRP mathematical methods and computer-aided tools developed, used or being designed by KfK are discussed. In conclusion, future research to be pursued in information processing and applied mathematics in support of reliable operation of NRP's is proposed. (Auth.)

  5. 75 FR 52917 - Defense Federal Acquisition Regulation Supplement (DFARS); Warranty Tracking of Serialized Items...

    Science.gov (United States)

    2010-08-30

    ... Business Communication Council (EHIBCC) and Health Industry Business Communication Council (HIBCC), as... Communication Council (EHIBCC) and Health Industry Business Communication Council (HIBCC), as indicated in the... Communication Council (EHIBCC) and Health Industry Business Communication Council (HIBCC). (h) Warranty...

  6. Optimising Age-Replacement and Extended Non-Renewing Warranty Policies in Lifecycle Costing

    OpenAIRE

    Wu, Shaomin; Longhurst, Phil

    2011-01-01

    This paper analyses the life cycle cost of equipment protected by both base and extended warranty policies from a consumer's perspective. We assume that the equipment has two types of failure: minor and catastrophic. A minor failure can be corrected with minimal repair whereas a catastrophic failure can only be removed by a replacement. It is assumed that equipment is maintained at no charge to the consumer during the warranty period, whereas the consumer is fully charged for any maintenance ...

  7. Training improves interobserver reliability for the diagnosis of scaphoid fracture displacement.

    Science.gov (United States)

    Buijze, Geert A; Guitton, Thierry G; van Dijk, C Niek; Ring, David

    2012-07-01

    The diagnosis of displacement in scaphoid fractures is notorious for poor interobserver reliability. We tested whether training can improve interobserver reliability and sensitivity, specificity, and accuracy for the diagnosis of scaphoid fracture displacement on radiographs and CT scans. Sixty-four orthopaedic surgeons rated a set of radiographs and CT scans of 10 displaced and 10 nondisplaced scaphoid fractures for the presence of displacement, using a web-based rating application. Before rating, observers were randomized to a training group (34 observers) and a nontraining group (30 observers). The training group received an online training module before the rating session, and the nontraining group did not. Interobserver reliability for training and nontraining was assessed by Siegel's multirater kappa and the Z-test was used to test for significance. There was a small, but significant difference in the interobserver reliability for displacement ratings in favor of the training group compared with the nontraining group. Ratings of radiographs and CT scans combined resulted in moderate agreement for both groups. The average sensitivity, specificity, and accuracy of diagnosing displacement of scaphoid fractures were, respectively, 83%, 85%, and 84% for the nontraining group and 87%, 86%, and 87% for the training group. Assuming a 5% prevalence of fracture displacement, the positive predictive value was 0.23 in the nontraining group and 0.25 in the training group. The negative predictive value was 0.99 in both groups. Our results suggest training can improve interobserver reliability and sensitivity, specificity and accuracy for the diagnosis of scaphoid fracture displacement, but the improvements are slight. These findings are encouraging for future research regarding interobserver variation and how to reduce it further.

  8. Improved radiograph measurement inter-observer reliability by use of statistical shape models

    Energy Technology Data Exchange (ETDEWEB)

    Pegg, E.C., E-mail: elise.pegg@ndorms.ox.ac.uk [University of Oxford, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, Nuffield Orthopaedic Centre, Windmill Road, Oxford OX3 7LD (United Kingdom); Mellon, S.J., E-mail: stephen.mellon@ndorms.ox.ac.uk [University of Oxford, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, Nuffield Orthopaedic Centre, Windmill Road, Oxford OX3 7LD (United Kingdom); Salmon, G. [University of Oxford, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, Nuffield Orthopaedic Centre, Windmill Road, Oxford OX3 7LD (United Kingdom); Alvand, A., E-mail: abtin.alvand@ndorms.ox.ac.uk [University of Oxford, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, Nuffield Orthopaedic Centre, Windmill Road, Oxford OX3 7LD (United Kingdom); Pandit, H., E-mail: hemant.pandit@ndorms.ox.ac.uk [University of Oxford, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, Nuffield Orthopaedic Centre, Windmill Road, Oxford OX3 7LD (United Kingdom); Murray, D.W., E-mail: david.murray@ndorms.ox.ac.uk [University of Oxford, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, Nuffield Orthopaedic Centre, Windmill Road, Oxford OX3 7LD (United Kingdom); Gill, H.S., E-mail: richie.gill@ndorms.ox.ac.uk [University of Oxford, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, Nuffield Orthopaedic Centre, Windmill Road, Oxford OX3 7LD (United Kingdom)

    2012-10-15

    Pre- and post-operative radiographs of patients undergoing joint arthroplasty are often examined for a variety of purposes including preoperative planning and patient assessment. This work examines the feasibility of using active shape models (ASM) to semi-automate measurements from post-operative radiographs for the specific case of the Oxford™ Unicompartmental Knee. Measurements of the proximal tibia and the position of the tibial tray were made using the ASM model and manually. Data were obtained by four observers and one observer took four sets of measurements to allow assessment of the inter- and intra-observer reliability, respectively. The parameters measured were the tibial tray angle, the tray overhang, the tray size, the sagittal cut position, the resection level and the tibial width. Results demonstrated improved reliability (average of 27% and 11.2% increase for intra- and inter-reliability, respectively) and equivalent accuracy (p > 0.05 for compared data values) for all of the measurements using the ASM model, with the exception of the tray overhang (p = 0.0001). Less time (15 s) was required to take measurements using the ASM model compared with manual measurements, which was significant. These encouraging results indicate that semi-automated measurement techniques could improve the reliability of radiographic measurements.

  9. Improved radiograph measurement inter-observer reliability by use of statistical shape models

    International Nuclear Information System (INIS)

    Pegg, E.C.; Mellon, S.J.; Salmon, G.; Alvand, A.; Pandit, H.; Murray, D.W.; Gill, H.S.

    2012-01-01

    Pre- and post-operative radiographs of patients undergoing joint arthroplasty are often examined for a variety of purposes including preoperative planning and patient assessment. This work examines the feasibility of using active shape models (ASM) to semi-automate measurements from post-operative radiographs for the specific case of the Oxford™ Unicompartmental Knee. Measurements of the proximal tibia and the position of the tibial tray were made using the ASM model and manually. Data were obtained by four observers and one observer took four sets of measurements to allow assessment of the inter- and intra-observer reliability, respectively. The parameters measured were the tibial tray angle, the tray overhang, the tray size, the sagittal cut position, the resection level and the tibial width. Results demonstrated improved reliability (average of 27% and 11.2% increase for intra- and inter-reliability, respectively) and equivalent accuracy (p > 0.05 for compared data values) for all of the measurements using the ASM model, with the exception of the tray overhang (p = 0.0001). Less time (15 s) was required to take measurements using the ASM model compared with manual measurements, which was significant. These encouraging results indicate that semi-automated measurement techniques could improve the reliability of radiographic measurements

  10. Improved Reliability of SiC Pressure Sensors for Long Term High Temperature Applications

    Science.gov (United States)

    Okojie, R. S.; Nguyen, V.; Savrun, E.; Lukco, D.

    2011-01-01

    We report advancement in the reliability of silicon carbide pressure sensors operating at 600 C for extended periods. The large temporal drifts in zero pressure offset voltage at 600 C observed previously were significantly suppressed to allow improved reliable operation. This improvement was the result of further enhancement of the electrical and mechanical integrity of the bondpad/contact metallization, and the introduction of studded bump bonding on the pad. The stud bump contact promoted strong adhesion between the Au bond pad and the Au die-attach. The changes in the zero offset voltage and bridge resistance over time at temperature were explained by the microstructure and phase changes within the contact metallization, that were analyzed with Auger electron spectroscopy (AES) and field emission scanning electron microscopy (FE-SEM).

  11. Good performance in Japan is proof of continuing safety and reliability improvement practice

    International Nuclear Information System (INIS)

    Sumi, Y.

    1987-01-01

    Nuclear power is a vital energy supply source for both security and economy for such countries as Japan whose sources of energy are dependent on imported materials. This is the very reason why Japan gives her national priority to the improvement of nuclear power safety and reliability. As of the end of 1986, total nuclear power capacity owned and operated by private utility companies in Japan amounted to 24521 MW with 32 units sharing -- 19% of the total generating capacity. Moreover, during 1986 these units scored a remarkably high capacity factor of 76.2% and shared almost 28% of the nationwide electric power production, thereby contributing to a considerable saving of imported sources of energy. This outstanding record has been achieved by the parties concerned who dedicated themselves to furthering nuclear plant safety and reliability improvement. In this connection, this paper summarizes those key factors contributing to the good nuclear power plant performance of the Kansai Electric Power Company

  12. Attitude Control of Quad-rotor by Improving the Reliability of Multi-Sensor System

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Dong Hyeon; Chong, Kil To [Chon-bok National University, Jeonju (Korea, Republic of); Park, Jong Ho [Seonam University, Namwon (Korea, Republic of); Ryu, Ji Hyoung [ETRI, Daejeon (Korea, Republic of)

    2015-05-15

    This paper presents the results of study for improving the reliability of quadrotor attitude control by applying a multi-sensor along with a data fusion algorithm. First, a mathematical model of the quadrotor dynamics was developed. Then, using the quadrotor mathematical model, simulations were performed using the improved reliability multi-sensor data as the inputs. From the simulation results, we designed a Gimbal-equipped quadrotor system. With the quadrotor in a hover state, we performed experiments according to the angle change of the user's specifications . We then calculated the attitude control data from the actual experimental data. Furthermore, with additional simulations, we verified the performance of the designed quadrotor attitude control system with multiple sensors.

  13. JOINT DETERMINATION OF PRICE, WAR RANTY LENGTH AND PRODUCTION QUANTITY FOR NEW PRODUCTS UNDER FREE RENEWAL WARRANTY POLICY

    Directory of Open Access Journals (Sweden)

    K. Jeyakumar

    2010-03-01

    Full Text Available An optimal business strategy which integrates the decisions, such as pricing, production quantity, and custom er service, in or der to maximize profit is vital for any manufacturing industry. Post sale factors like warranty, spare parts availability, maintenance, service and cost play an important role in the sale of a product. As better warranty signals higher product quality which provides greater assurance to customers, warranty is an important factor in marketing new products. In this paper, a decision model with the price, warranty length and production quantity of a product as decision variables to maximize profit based on the pre-determined product life cycle is presented. The study considers free renewal warranty policy for producers in the static sales market. The expected number of renewals based on the warranty length is derived for lognormally distributed products. The effect of model parameters on the profit is studied.

  14. Improvements in the consistency of fabrication and the reliability of nuclear fuels through quality assurance

    International Nuclear Information System (INIS)

    Sifferlen, R.

    1976-01-01

    By establishing correlations between rejection level and fabrication parameters, quality assurance can guide corrective action for improving the consistency of fabrication and the reliability of fuel elements. The author cites examples relating to the quality of the uranium in metallic fuels, the influence of the parent metal on the welding of zirconium alloys, the behaviour of the springs inside the cladding during the welding of plugs and the behaviour of uranium oxide pellets. (author)

  15. Assessing motivation for work environment improvements: internal consistency, reliability and factorial structure.

    Science.gov (United States)

    Hedlund, Ann; Ateg, Mattias; Andersson, Ing-Marie; Rosén, Gunnar

    2010-04-01

    Workers' motivation to actively take part in improvements to the work environment is assumed to be important for the efficiency of investments for that purpose. That gives rise to the need for a tool to measure this motivation. A questionnaire to measure motivation for improvements to the work environment has been designed. Internal consistency and test-retest reliability of the domains of the questionnaire have been measured, and the factorial structure has been explored, from the answers of 113 employees. The internal consistency is high (0.94), as well as the correlation for the total score (0.84). Three factors are identified accounting for 61.6% of the total variance. The questionnaire can be a useful tool in improving intervention methods. The expectation is that the tool can be useful, particularly with the aim of improving efficiency of companies' investments for work environment improvements. Copyright 2010 Elsevier Ltd. All rights reserved.

  16. Active Thermal Control for Reliability Improvement of MOS-gated Power Devices

    DEFF Research Database (Denmark)

    Soldati, Alessandro; Concari, Carlo; Dossena, Fabrizio

    2017-01-01

    reliability and lifetime. These figures can then be improved, which eases the adoption of electrification in markets, such as transportation, where they are still below target values. The proposed ATC method leaves electric load parameters untouched, while acting dynamically on gate parameters, namely voltage...... and resistance. A model-predictive control (MPC) strategy is used to determine the most suitable parameters to use. Simulations of the control scheme are presented first, to predict the potential benefits on temperature swing amplitude, and the consequent improvements in terms of device lifetime are inferred...

  17. A Simulation Model for Machine Efficiency Improvement Using Reliability Centered Maintenance: Case Study of Semiconductor Factory

    Directory of Open Access Journals (Sweden)

    Srisawat Supsomboon

    2014-01-01

    Full Text Available The purpose of this study was to increase the quality of product by focusing on the machine efficiency improvement. The principle of the reliability centered maintenance (RCM was applied to increase the machine reliability. The objective was to create preventive maintenance plan under reliability centered maintenance method and to reduce defects. The study target was set to reduce the Lead PPM for a test machine by simulating the proposed preventive maintenance plan. The simulation optimization approach based on evolutionary algorithms was employed for the preventive maintenance technique selection process to select the PM interval that gave the best total cost and Lead PPM values. The research methodology includes procedures such as following the priority of critical components in test machine, analyzing the damage and risk level by using Failure Mode and Effects Analysis (FMEA, calculating the suitable replacement period through reliability estimation, and optimizing the preventive maintenance plan. From the result of the study it is shown that the Lead PPM of test machine can be reduced. The cost of preventive maintenance, cost of good product, and cost of lost product were decreased.

  18. Engineering, maintenance, and initiatives to improve LAMPF beam availability and system reliability

    International Nuclear Information System (INIS)

    Harris, H.W.; DeHaven, R.A.; Hart, V.E.; Parsons, W.M.; Sturrock, J.C.

    1992-01-01

    Two different requirements are driving engineering studies and hardware development to improve LAMPF. The first is concerned with component and system improvements to increase beam availability during the LAMPF production cycle. Hardware changes in RF, power supplies, and magnets are being implemented to increase mean time between failure and reduce time to replace or repair failed units. A joint LAMPF-Industry project is on-going to improve reliability of RF components. A component test stand is being refurbished to include significant development capability. The second approach includes several changes that will increase the duty factor of the existing accelerator. Major changes are being evaluated for replacing the front end of the accelerator. Other changes improving the high brightness capability could result in a new performance plateau for LAMPF. 2 refs., 2 figs

  19. Engineering, maintenance, and new initiatives to improve LAMPF beam availability and system reliability

    International Nuclear Information System (INIS)

    Harris, H.W.; DeHaven, R.A.; Hart, V.E.; Parsons, W.M.; Sturrock, J.C.

    1992-01-01

    Two different requirements are driving engineering studies and hardware development to improve LAMPF. The first is concerned with component and system improvements to increase beam availability during the LAMPF production cycle. Hardware changes in RF, power supplies, and magnets are being implemented to increase mean time between failure and reduce time to replace or repair failed units. A joint LAMPF-Industry project is on-going to improve reliability of RF components. A component test stand is being refurbished to include significant development capability. The second approach includes several changes that will increase the duty factor of the existing accelerator. Major changes are being evaluated for replacing the front end of the accelerator. Other changes improving high brightness capability could result in a new performance plateau for LAMPF

  20. Improved reliability of wind turbine towers with active tuned mass dampers (ATMDs)

    Science.gov (United States)

    Fitzgerald, Breiffni; Sarkar, Saptarshi; Staino, Andrea

    2018-04-01

    Modern multi-megawatt wind turbines are composed of slender, flexible, and lightly damped blades and towers. These components exhibit high susceptibility to wind-induced vibrations. As the size, flexibility and cost of the towers have increased in recent years, the need to protect these structures against damage induced by turbulent aerodynamic loading has become apparent. This paper combines structural dynamic models and probabilistic assessment tools to demonstrate improvements in structural reliability when modern wind turbine towers are equipped with active tuned mass dampers (ATMDs). This study proposes a multi-modal wind turbine model for wind turbine control design and analysis. This study incorporates an ATMD into the tower of this model. The model is subjected to stochastically generated wind loads of varying speeds to develop wind-induced probabilistic demand models for towers of modern multi-megawatt wind turbines under structural uncertainty. Numerical simulations have been carried out to ascertain the effectiveness of the active control system to improve the structural performance of the wind turbine and its reliability. The study constructs fragility curves, which illustrate reductions in the vulnerability of towers to wind loading owing to the inclusion of the damper. Results show that the active controller is successful in increasing the reliability of the tower responses. According to the analysis carried out in this paper, a strong reduction of the probability of exceeding a given displacement at the rated wind speed has been observed.

  1. Reliability of infarct volumetry: Its relevance and the improvement by a software-assisted approach.

    Science.gov (United States)

    Friedländer, Felix; Bohmann, Ferdinand; Brunkhorst, Max; Chae, Ju-Hee; Devraj, Kavi; Köhler, Yvette; Kraft, Peter; Kuhn, Hannah; Lucaciu, Alexandra; Luger, Sebastian; Pfeilschifter, Waltraud; Sadler, Rebecca; Liesz, Arthur; Scholtyschik, Karolina; Stolz, Leonie; Vutukuri, Rajkumar; Brunkhorst, Robert

    2017-08-01

    Despite the efficacy of neuroprotective approaches in animal models of stroke, their translation has so far failed from bench to bedside. One reason is presumed to be a low quality of preclinical study design, leading to bias and a low a priori power. In this study, we propose that the key read-out of experimental stroke studies, the volume of the ischemic damage as commonly measured by free-handed planimetry of TTC-stained brain sections, is subject to an unrecognized low inter-rater and test-retest reliability with strong implications for statistical power and bias. As an alternative approach, we suggest a simple, open-source, software-assisted method, taking advantage of automatic-thresholding techniques. The validity and the improvement of reliability by an automated method to tMCAO infarct volumetry are demonstrated. In addition, we show the probable consequences of increased reliability for precision, p-values, effect inflation, and power calculation, exemplified by a systematic analysis of experimental stroke studies published in the year 2015. Our study reveals an underappreciated quality problem in translational stroke research and suggests that software-assisted infarct volumetry might help to improve reproducibility and therefore the robustness of bench to bedside translation.

  2. Substation design improvement with a probabilistic reliability approach using the TOPASE program

    Energy Technology Data Exchange (ETDEWEB)

    Bulot, M.; Heroin, G.; Bergerot, J-L.; Le Du, M. [Electricite de France (France)

    1997-12-31

    TOPASE, (the French acronym for Probabilistic Tools and Data Processing for the Analysis of Electric Systems), developed by Electricite de France (EDF) to perform reliability studies on transmission substations, was described. TOPASE serves a dual objective of assisting in the automation of HV substation studies, as well as enabling electrical systems experts who are not necessarily specialists in reliability studies to perform such studies. The program is capable of quantifying the occurrence rate of undesirable events and of identifying critical equipment and the main incident scenarios. The program can be used to improve an existing substation, to choose an HV structure during the design stage, or to choose a system of protective devices. Data collected during 1996 and 1997 will be analyzed to identify useful experiences and to validate the basic concepts of the program. 4 figs.

  3. ERP application of real-time vdc-enabled last planner system for planning reliability improvement

    DEFF Research Database (Denmark)

    Cho, S.; Sørensen, Kristian Birch; Fischer, M.

    2009-01-01

    The Last Planner System (LPS) has since its introduction in 1994 become a widely used method of AEC practitioners for improvement of planning reliability and tracking and monitoring of project progress. However, the observations presented in this paper indicate that the last planners...... and coordinators are in need of a new system that integrates the existing LPS with Virtual Design and Construction (VDC), Enterprise Resource Planning (ERP) systems, and automatic object identification by means of Radio Frequency Identification (RFID) technology. This is because current practice of the LPS...... implementations is guesswork-driven, textual report-generated, hand-updated, and even interpersonal trust-oriented, resulting in less accurate and reliable plans. This research introduces a prototype development of the VREL (VDC + RFID + ERP + LPS) integration to generate a real-time updated cost + physical...

  4. STUDIES ON IGBT MODULE TO IMPROVE THE RELIABILITY OF POWER ELECTRONIC SYSTEMS

    DEFF Research Database (Denmark)

    Choi, Uimin

    component level to converter level. It is divided into two main parts: the first part, which consists of Chapters 2 and 3, is reliability studies of the IGBT module regarding thermal stresses and the second part, composed of Chapters 4 and 5, discusses strategies to improve the reliability and availability...... are presented. Then, in Chapter 3, the effect of junction temperature swing duration t△Tj on the lifetime of the transfer molded Intelligent Power IGBT Module is investigated and modeled based on the power cycling test results. In addition, the physics-of-failure analysis results of the tested modules...... are presented. Finally, in Chapters 4 and 5, open-circuit fault detection and fault-tolerant control methods are proposed for two kinds of neutral-point clamped three-level inverters T-type and NPC inverters. One of main contributions in this project is the development of an apparatus and methodology...

  5. Prediction method of long-term reliability in improving residual stresses by means of surface finishing

    International Nuclear Information System (INIS)

    Sera, Takehiko; Hirano, Shinro; Chigusa, Naoki; Okano, Shigetaka; Saida, Kazuyoshi; Mochizuki, Masahito; Nishimoto, Kazutoshi

    2012-01-01

    Surface finishing methods, such as Water Jet Peening (WJP), have been applied to welds in some major components of nuclear power plants as a counter measure to Primary Water Stress Corrosion Cracking (PWSCC). In addition, the methods of surface finishing (buffing treatment) is being standardized, and thus the buffing treatment has been also recognized as the well-established method of improving stress. On the other hand, the long-term stability of peening techniques has been confirmed by accelerated test. However, the effectiveness of stress improvement by surface treatment is limited to thin layers and the effect of complicated residual stress distribution in the weld metal beneath the surface is not strictly taken into account for long-term stability. This paper, therefore, describes the accelerated tests, which confirmed that the long-term stability of the layer subjected to buffing treatment was equal to that subjected to WJP. The long-term reliability of very thin stress improved layer was also confirmed through a trial evaluation by thermal elastic-plastic creep analysis, even if the effect of complicated residual stress distribution in the weld metal was excessively taken into account. Considering the above findings, an approach is proposed for constructing the prediction method of the long-term reliability of stress improvement by surface finishing. (author)

  6. Evaluation and improvement in nondestructive examination (NDE) reliability for in-service inspection of light water reactors

    International Nuclear Information System (INIS)

    Deffenbaugh, J.D.; Good, M.S.; Green, E.R.; Heasler, P.G.; Simonen, F.A.; Spanner, J.C.; Taylor, T.T.

    1988-01-01

    The evaluation and improvement of NDE Reliability for In-service Inspection (ISI) of Light Water Reactors (NDE Reliability) Program at Pacific Northwest Laboratory (PNL) was established to determine the reliability of current ISI techniques and to develop recommendations that will ensure a suitably high inspection reliability. The objectives of this NRC program are to: determine the reliability of ultrasonic ISI performed on commercial light-water reactor (LWR) primary systems; determine the impact of NDE unreliability on system safety and determine the level of inspection reliability required to ensure a suitably low failure probability using probabilistic fracture mechanics analysis; evaluate the degree of reliability improvement that could be achieved using improved and advanced NDE technique; and recommend revisions to ASME Code, Section XI, and Regulatory Requirements, based on material properties, service conditions, and NDE uncertainties, that will ensure suitably low failure probabilities. The program consists of three basic tasks: a Piping task, a Pressure Vessel task, and an Evaluation and Improvement in NDE Reliability task. The major efforts were concentrated in the Piping task and the Evaluation and Improvement in NDE Reliability task

  7. Role of recent research in improving check valve reliability at nuclear power plants

    International Nuclear Information System (INIS)

    Kalsi, M.S.; Horst, C.L.; Wang, J.K.; Sharma, V.

    1990-01-01

    Check valve failures at nuclear power plants in recent years have led to serious safety concerns, and caused extensive damage to other plant components which had a significant impact on plant availability. In order to understand the failure mechanism and improve the reliability of check valves, a systematic research effort was proposed by Kalsi Engineering, Inc. to U.S. Nuclear Regulatory Commission (NRC). The overall goal of the research was to develop models for predicting the performance and degradation of swing check valves in nuclear power plant systems so that appropriate preventive maintenance or design modifications can be performed to improve the reliability of check valves. Under Phase I of this research, a large matrix of tests was run with instrumented swing check valves to determine the stability of the disc under a variety of upstream flow disturbances, covering a wide range of disc stop positions and flow velocities in two different valve sizes. The goals of Phase II research were to develop predictive models which quantify the anticipated degradation of swing check valves that have flow disturbances closely upstream of the valve and are operating under flow velocities that do not result in full disc opening. This research allows the inspection/maintenance activities to be focussed on those check valves that are more likely to suffer premature degradation. The quantitative wear and fatigue prediction methodology can be used to develop a sound preventive maintenance program. The results of the research also show the improvements in check valve performance/reliability that can be achieved by certain modifications in the valve design

  8. Lecture 8: Data Reliability at CERN and Ideas on How to Improve it

    CERN Multimedia

    CERN. Geneva

    2013-01-01

    The talk will give an overview of data management activities at CERN focusing on the ongoing research activities aiming to improve data and service reliability. Alberto Pace is a member if the IT department at CERN where he leads the Data and Storage services group ensuring a coherent development process for Physics Data management activities, strongly driven by operational and user needs. He has more than 25 years experience in computing services, infrastructure, software engineering, accelerator control and accelerator operation. He graduated in Electronic Engineering from Politecnico di Milano (Italy).

  9. Improvement in the reliability of shells for light water reactors by manufacturing from hollow ingots

    International Nuclear Information System (INIS)

    Bocquet, P.; Blondeau, R.; Poitrault, I.; Badeau, J.P.; Dumont, R.

    1989-01-01

    The example of forging shells for PWR type reactors is proposed to show how the choice of the manufacturing process may be of prime importance for the component integrity by the reduction of the detrimental effects of segregations. The forging shells (20MnMoNi55) manufactured from hollow ingot are free of any segregation in the critical area located just at the internal surface and sub-surface. Manufacturing problems associated to these segregations in shells issued from conventional ingots, in particular welding difficulties for cladding, have been reduced or eleminated. The reliability of these components present an improved resistance to irradiation embrittlement. (DG)

  10. A review of manufacturing metrology for improved reliability of silicon photovoltaic modules

    Science.gov (United States)

    Davis, Kristopher O.; Walters, Joseph; Schneller, Eric; Seigneur, Hubert; Brooker, R. Paul; Scardera, Giuseppe; Rodgers, Marianne P.; Mohajeri, Nahid; Shiradkar, Narendra; Dhere, Neelkanth G.; Wohlgemuth, John; Rudack, Andrew C.; Schoenfeld, Winston V.

    2014-10-01

    In this work, the use of manufacturing metrology across the supply chain to improve crystalline silicon (c-Si) photovoltaic (PV) module reliability and durability is addressed. Additionally, an overview and summary of a recent extensive literature survey of relevant measurement techniques aimed at reducing or eliminating the probability of field failures is presented. An assessment of potential gaps is also given, wherein the PV community could benefit from new research and demonstration efforts. This review is divided into three primary areas representing different parts of the c-Si PV supply chain: (1) feedstock production, crystallization and wafering; (2) cell manufacturing; and (3) module manufacturing.

  11. Improving the reliability of peer-reviewed publications: We are all in it together

    Directory of Open Access Journals (Sweden)

    Stephen A. Bustin

    2016-03-01

    Full Text Available The current, and welcome, focus on standardization of techniques and transparency of reporting in the biomedical, peer-reviewed literature is commendable. However, that focus has been intermittent as well as lacklustre and so failed to tackle the alarming lack of reliability and reproducibly of biomedical research. Authors have access to numerous recommendations, ranging from simple standards dealing with technical issues to those regulating clinical trials, suggesting that improved reporting guidelines are not the solution. The elemental solution is for editors to require meticulous implementation of their journals’ instructions for authors and reviewers and stipulate that no paper is published without a transparent, complete and accurate materials and methods section.

  12. Improving the reliability of GUB-20000 gamma unit for large laboratory animals irradiation

    International Nuclear Information System (INIS)

    Videnskij, V.G.

    1994-01-01

    GUB-20000 gamma unit for large laboratory animals irradiation is described and results of investigation into its reliability improvement are considered. Cables of superstrength high-modular (SSHM) polymer fibre and capron fiber were tested to establish their applicability in the above unit. Samples were exposed to gamma-radiation and fast electrons and were tested for tensile properties. Application of SSHM-fiber cables to modernize the GUB-20000 unit was found to be perspective due to superhigh radiation strength. 5 refs., 1 tab

  13. Improved structural integrity through advances in reliable residual stress measurement: the impact of ENGIN-X

    Science.gov (United States)

    Edwards, L.; Santisteban, J. R.

    The determination of accurate reliable residual stresses is critical to many fields of structural integrity. Neutron stress measurement is a non-destructive technique that uniquely provides insights into stress fields deep within engineering components and structures. As such, it has become an increasingly important tool within engineering, leading to improved manufacturing processes to reduce stress and distortion as well as to the definition of more precise lifing procedures. This paper describes the likely impact of the next generation of dedicated engineering stress diffractometers currently being constructed and the utility of the technique using examples of residual stresses both beneficial and detrimental to structural integrity.

  14. 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.

  15. An improved IEEE 802.11 protocol for reliable data transmission in power distribution fault diagnosis

    Energy Technology Data Exchange (ETDEWEB)

    Campoccia, F.; Di Silvestre, M.L.; Sanseverino, E.R.; Zizzo, G. [Palermo Univ., Palermo (Italy)

    2010-10-15

    In power systems, on-line transmission between local units and the central unit can be done by means of power line communications or wireless technology. During an electrical fault, the reliability of the distribution system depends on the security of the timely protective and restorative actions on the network. This paper focused on the WiFi system because of its economy and ease of installation. However, WiFi systems are typically managed by the IEEE 802.11 protocol, which is not reliable in terms of security in data communication. In WiFi networks, data is divided into packets and sent in succession to reduce errors within the radio channel. The IEEE 802.11 protocol has high probability for loss of packets or delay in their transmission. In order to ensure the reliability of data transmission times between two terminal units connected by WiFi stations, a new protocol was derived by modifying the IEEE 802.11. The improvements of the new protocol were highlighted and its capability for the diagnostic service was verified. The modified protocol eliminates the danger of collisions between packets and optimizes the transmission time for sending information. 6 refs., 7 tabs., 8 figs.

  16. Bootstrap analysis of designed experiments for reliability improvement with a non-constant scale parameter

    International Nuclear Information System (INIS)

    Wang, Guodong; He, Zhen; Xue, Li; Cui, Qingan; Lv, Shanshan; Zhou, Panpan

    2017-01-01

    Factors which significantly affect product reliability are of great interest to reliability practitioners. This paper proposes a bootstrap-based methodology for identifying significant factors when both location and scale parameters of the smallest extreme value distribution vary over experimental factors. An industrial thermostat experiment is presented, analyzed, and discussed as an illustrative example. The analysis results show that 1) the misspecification of a constant scale parameter may lead to misidentify spurious effects; 2) the important factors identified by different bootstrap methods (i.e., percentile bootstrapping, bias-corrected percentile bootstrapping, and bias-corrected and accelerated percentile bootstrapping) are different; 3) the number of factors affecting 10th percentile lifetime significantly is less than the number of important factors identified at 63.21th percentile. - Highlights: • Product reliability is improved by design of experiments under both scale and location parameters of smallest extreme value distribution vary with experimental factors. • A bootstrap-based methodology is proposed to identify important factors which affect 100pth lifetime percentile significantly. • Bootstrapping confidence intervals associating experimental factors are obtained by using three bootstrap methods (i.e., percentile bootstrapping, bias-corrected percentile bootstrapping, and bias-corrected and accelerated percentile bootstrapping). • The important factors identified by different bootstrap methods are different. • The number of factors affecting 10th percentile significantly is less than the number of important factors identified at 63.21th percentile.

  17. 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.

  18. Effects of product\\'s warranty on customers\\' preferences: empirical findings on reverse logistics models

    Directory of Open Access Journals (Sweden)

    Arsalan Najmi

    2014-09-01

    Full Text Available Background: IT products are now becoming the part of every one's life. Since Pakistan didn't manufacture IT products, so the customers had to purchase the products that are available in the markets. During such purchase, customers not only gave preference to brand or price or both but they also consider its warranty so that they are secured with the post purchase risks. Methods: This study was aimed to identify the impact of the warranty on customers' preferences towards brand and price. A conceptual framework was made on the basis of available literature and then data was collected. It was collected from 298 respondents through survey questionnaire and after applying Factor Analysis, One Way MANOVA was applied on the factors. Results and conclusions: The study found that the product's warranty has a significant impact on preferences towards brand, concern for price and price intentions whereas the impact on willingness to pay was found insignificant. The results conclude that Pakistani customers need a branded IT product on competitive prices, which give more in less along with the warranty so that they can enjoy the same quality of the product for a period of time whereas, they are not willing to pay any additional amount for the product just because of Warranty.

  19. Optimal Overhaul-Replacement Policies for Repairable Machine Sold with Warranty

    Directory of Open Access Journals (Sweden)

    Kusmaningrum Soemadi

    2014-12-01

    Full Text Available This research deals with an overhaul-replacement policy for a repairable machine sold with Free Replacement Warranty (FRW. The machine will be used for a finite horizon, T (T <, and evaluated at a fixed interval, s (s< T. At each evaluation point, the buyer considers three alternative decisions i.e. Keep the machine, Overhaul it, or Replace it with a new identical one. An overhaul can reduce the machine age virtually, but not to a point that the machine is as good as new. If the machine fails during the warranty period, it is rectified at no cost to the buyer. Any failure occurring before and after the expiry of the warranty is restored by minimal repair. An overhaul-replacement policy is formulated for such machines by using dynamic programming approach to obtain the buyer’s optimal policy. The results show that a significant rejuvenation effect due to overhaul may extend the length of machine life cycle and delay the replacement decision. In contrast, the warranty stimulates early machine replacement and by then increases the replacement frequencies for a certain range of replacement cost. This demonstrates that to minimize the total ownership cost over T the buyer needs to consider the minimal repair cost reduction due to rejuvenation effect of overhaul as well as the warranty benefit due to replacement. Numerical examples are presented for both illustrating the optimal policy and describing the behavior of the optimal solution.

  20. Reducing variability of workforce as a tool to improve plan reliability

    DEFF Research Database (Denmark)

    Wandahl, Søren; Yicheng, S.; Zygmunt, K. J.

    Variability of flow is recognized as the greatest obstacle to production management. Since the work flow and labour flow are two dominators of work performance, it is important to manage them simultaneously. The objective of this paper is to examine whether by reducing the variance of a labour flow......, a plan reliability can be improved, therefore, three different construction labour data sets have been examined by utilizing Monte Carlo Simulation, to analyze the probability to finish simulated projects within a certain time. The research findings revealed that reducing variance in the workforce flow...... does not necessarily shorten the project length, nevertheless it increases probability to finish the tasks within a critical path duration. Additionally, it was concluded, that reducing the variance of crew allocation can improve the productivity....

  1. Engineering of electrical systems of nuclear power stations for improved reliability

    International Nuclear Information System (INIS)

    Narasinga Rao, S.N.; Ramanathan, K.; Choudhary, N.N.

    1977-01-01

    Operational problems experienced in electrical systems/equipment of the Tarapur Atomic Power Station (TAPS) and the Rajasthan Atomic Power Station (RAPS) and their solutions are dealt in detail. This experience has led to new design concepts which are being introduced for improved reliability in design of the Madras Atomic Power Project (MAPP) and the Narora Atomic Power Project (NAPP). Saline pollution on switchyard equipments was the major problem of the TAPS due to its coastal location. Saline pollution resulted in flash over of insulators and failure of clamps. The problem was solved by suitable changes in insulators, conductors, transformers, switches and arranging portable live line washing of the switchyard equipment. In MAPP which is also located on coast, an indoor switchyard is built. NAPP is located in a seismic zone, therefore, all equipment is specified for appropriate seismic duty. Various other improvements are described. (M.G.B.)

  2. Improved Reliability of Single-Phase PV Inverters by Limiting the Maximum Feed-in Power

    DEFF Research Database (Denmark)

    Yang, Yongheng; Wang, Huai; Blaabjerg, Frede

    2014-01-01

    Grid operation experiences have revealed the necessity to limit the maximum feed-in power from PV inverter systems under a high penetration scenario in order to avoid voltage and frequency instability issues. A Constant Power Generation (CPG) control method has been proposed at the inverter level...... devices, allowing a quantitative prediction of the power device lifetime. A study case on a 3 kW single-phase PV inverter has demonstrated the advantages of the CPG control in terms of improved reliability.......Grid operation experiences have revealed the necessity to limit the maximum feed-in power from PV inverter systems under a high penetration scenario in order to avoid voltage and frequency instability issues. A Constant Power Generation (CPG) control method has been proposed at the inverter level....... The CPG control strategy is activated only when the DC input power from PV panels exceeds a specific power limit. It enables to limit the maximum feed-in power to the electric grids and also to improve the utilization of PV inverters. As a further study, this paper investigates the reliability performance...

  3. Researching and improving the reliability of reactor protection system of Qinshan nuclear power plant

    International Nuclear Information System (INIS)

    Jiang Zuyue; Sheng Jiannan

    1997-01-01

    Due to the original design defects of the Reactor Protection System (RPS) of Qinshan Nuclear Power Plant, this system has brought about a number of reactor shutdown accidents and Engineered Safety Features (ESF) mis-activation events which have seriously endangered safe and steady operation of the nuclear power plant. So over three years have been spent on research on the reform of the original design on the premise that the general wiring of the system should remain the same and that the system size should also remain small to be contained in the original cabinets. The following improvements were made: (1) Increase the system's anti-disturbance capability. The system's zero volt bus floating designs were modified to surmount the disturbance resulting from the bad isolation performance of impedance-isolated amplifier; Double grounds have been added to logical modules to surmount the disturbance resulting from zero volt floating bus during the replacement of single module with two connectors; The opto-coupling circuit in its oscillation input stage of Engineered Safety Features have been improved to increase its reliability. (2)Modify to output activation part of the system. The new type of output relays were selected and the relay activation circuits were redesigned in which switcher activation mode is used instead of amplifier activation mode so as to increase the reliability of relay operation and reduce the power consumption; CMOS buffer gates in the input and output stage of the circuit were used to match TTL circuits to CMOS circuits of the system

  4. Improving human reliability through better nuclear power plant system design. Progress report

    International Nuclear Information System (INIS)

    Golay, M.W.

    1995-01-01

    The project on open-quotes Development of a Theory of the Dependence of Human Reliability upon System Designs as a Means of Improving Nuclear Power Plant Performanceclose quotes has been undertaken in order to address the important problem of human error in advanced nuclear power plant designs. Most of the creativity in formulating such concepts has focused upon improving the mechanical reliability of safety related plant systems. However, the lack of a mature theory has retarded similar progress in reducing the likely frequencies of human errors. The main design mechanism used to address this class of concerns has been to reduce or eliminate the human role in plant operations and accident response. The plan of work being pursued in this project is to perform a set of experiments involving human subject who are required to operate, diagnose and respond to changes in computer-simulated systems, relevant to those encountered in nuclear power plants. In the tests the systems are made to differ in complexity in a systematic manner. The computer program used to present the problems to be solved also records the response of the operator as it unfolds. Ultimately this computer is also to be used in compiling the results of the project. The work of this project is focused upon nuclear power plant applications. However, the persuasiveness of human errors in using all sorts of electromechanical machines gives it a much greater potential importance. Because of this we are attempting to pursue our work in a fashion permitting broad generalizations

  5. Utilizing clad piping to improve process plant piping integrity, reliability, and operations

    International Nuclear Information System (INIS)

    Chakravarti, B.

    1996-01-01

    During the past four years carbon steel piping clad with type 304L (UNS S30403) stainless steel has been used to solve the flow accelerated corrosion (FAC) problem in nuclear power plants with exceptional success. The product is designed to allow ''like for like'' replacement of damaged carbon steel components where the carbon steel remains the pressure boundary and type 304L (UNS S30403) stainless steel the corrosion allowance. More than 3000 feet of piping and 500 fittings in sizes from 6 to 36-in. NPS have been installed in the extraction steam and other lines of these power plants to improve reliability, eliminate inspection program, reduce O and M costs and provide operational benefits. This concept of utilizing clad piping in solving various corrosion problems in industrial and process plants by conservatively selecting a high alloy material as cladding can provide similar, significant benefits in controlling corrosion problems, minimizing maintenance cost, improving operation and reliability to control performance and risks in a highly cost effective manner. This paper will present various material combinations and applications that appear ideally suited for use of the clad piping components in process plants

  6. Video training and certification program improves reliability of postischemic neurologic deficit measurement in the rat.

    Science.gov (United States)

    Taninishi, Hideki; Pearlstein, Molly; Sheng, Huaxin; Izutsu, Miwa; Chaparro, Rafael E; Goldstein, Larry B; Warner, David S

    2016-12-01

    Scoring systems are used to measure behavioral deficits in stroke research. Video-assisted training is used to standardize stroke-related neurologic deficit scoring in humans. We hypothesized that a video-assisted training and certification program can improve inter-rater reliability in assessing neurologic function after middle cerebral artery occlusion in rats. Three expert raters scored neurologic deficits in post-middle cerebral artery occlusion rats using three published systems having different complexity levels (3, 18, or 48 points). The system having the highest point estimate for the correlation between neurologic score and infarct size was selected to create a video-assisted training and certification program. Eight trainee raters completed the video-assisted training and certification program. Inter-rater agreement ( Κ: score) and agreement with expert consensus scores were measured before and after video-assisted training and certification program completion. The 48-point system correlated best with infarct size. Video-assisted training and certification improved agreement with expert consensus scores (pretraining = 65 ± 10, posttraining = 87 ± 14, 112 possible scores, P  0.4 (pretraining = 4, posttraining = 9), and number of categories with an improvement in the Κ: score from pretraining to posttraining (n = 6). Video-assisted training and certification improved trainee inter-rater reliability and agreement with expert consensus behavioral scores in rats after middle cerebral artery occlusion. Video-assisted training and certification may be useful in multilaboratory preclinical studies. © The Author(s) 2015.

  7. A Decision Optimization Model for Leased Manufacturing Equipment with Warranty under Forecasting Production/Maintenance Problem

    Directory of Open Access Journals (Sweden)

    Zied Hajej

    2015-01-01

    Full Text Available Due to the expensive production equipment, many manufacturers usually lease production equipment with a warranty period during a finite leasing horizon, rather than purchasing them. The lease contract contains the possibility of obtaining an extended warranty for a given additional cost. In this paper, based on the forecasting production/maintenance optimization problem, we develop a mathematical model to study the lease contract with basic and extended warranty based on win-win relationship between the lessee and the lessor. The influence of the production rates in the equipment degradation consequently on the total cost by each side during the finite leasing horizon is stated in order to determine a theoretical condition under which a compromise-pricing zone exists under different possibilities of maintenance policies.

  8. Optimizing two-dimensional renewable warranty policies for sensor embedded remanufactured products

    International Nuclear Information System (INIS)

    Alqahtani, Ammar; Gupta, Surendra M.

    2017-01-01

    Remanufactured products, in addition to being environment friendly, are popular with consumers because they can offer the latest technology with lower prices in comparison to brand new products. However, some consumers are hesitant to buy remanufactured products because they are skeptical about the quality of the remanufactured product and thus are unsure of the extent to which the product will render services when compared to a new product. A strategy that remanufacturers may employ to entice customers is to offer warranties on remanufactured products. To that end, this paper studies and scrutinizes the impact of offering renewing warranties on remanufactured products. Specifically, the paper suggests a methodology which simultaneously minimizes the cost incurred by the remanufacturers and maximizes the confidence of the consumers towards buying remanufacturing products. Design/methodology/approach: This study uses discrete-event simulation to optimize the implementation of a two-dimensional renewing warranty policy for remanufactured products. The implementation is illustrated using a specific product recovery system called the Advanced Remanufacturing-To-Order (ARTO) system. The experiments used in the study were designed using Taguchi’s Orthogonal Arrays to represent the entire domain of the recovery system so as to observe the system behavior under various experimental conditions. In order to determine the optimum strategy offered by the remanufacturer, various warranty and preventive maintenance scenarios were analyzed using pairwise t-tests along with one-way analysis of variance (ANOVA) and Tukey pairwise comparisons tests for every scenario. Findings: The proposed methodology is able to simultaneously minimize the cost incurred by the remanufacturer, optimize the warranty price and period, and optimize the preventive maintenance strategy resulting in increased consumer confidence. Originality/value: This is the first study that evaluates in a

  9. Optimizing two-dimensional renewable warranty policies for sensor embedded remanufactured products

    Directory of Open Access Journals (Sweden)

    Ammar Alqahtani

    2017-05-01

    Full Text Available Purpose: Remanufactured products, in addition to being environment friendly, are popular with consumers because they can offer the latest technology with lower prices in comparison to brand new products. However, some consumers are hesitant to buy remanufactured products because they are skeptical about the quality of the remanufactured product and thus are unsure of the extent to which the product will render services when compared to a new product. A strategy that remanufacturers may employ to entice customers is to offer warranties on remanufactured products. To that end, this paper studies and scrutinizes the impact of offering renewing warranties on remanufactured products. Specifically, the paper suggests a methodology which simultaneously minimizes the cost incurred by the remanufacturers and maximizes the confidence of the consumers towards buying remanufacturing products. Design/methodology/approach: This study uses discrete-event simulation to optimize the implementation of a two-dimensional renewing warranty policy for remanufactured products. The implementation is illustrated using a specific product recovery system called the Advanced Remanufacturing-To-Order (ARTO system. The experiments used in the study were designed using Taguchi’s Orthogonal Arrays to represent the entire domain of the recovery system so as to observe the system behavior under various experimental conditions. In order to determine the optimum strategy offered by the remanufacturer, various warranty and preventive maintenance scenarios were analyzed using pairwise t-tests along with one-way analysis of variance (ANOVA and Tukey pairwise comparisons tests for every scenario. Findings: The proposed methodology is able to simultaneously minimize the cost incurred by the remanufacturer, optimize the warranty price and period, and optimize the preventive maintenance strategy resulting in increased consumer confidence. Originality/value: This is the first study that

  10. Optimizing two-dimensional renewable warranty policies for sensor embedded remanufactured products

    Energy Technology Data Exchange (ETDEWEB)

    Alqahtani, Ammar; Gupta, Surendra M.

    2017-07-01

    Remanufactured products, in addition to being environment friendly, are popular with consumers because they can offer the latest technology with lower prices in comparison to brand new products. However, some consumers are hesitant to buy remanufactured products because they are skeptical about the quality of the remanufactured product and thus are unsure of the extent to which the product will render services when compared to a new product. A strategy that remanufacturers may employ to entice customers is to offer warranties on remanufactured products. To that end, this paper studies and scrutinizes the impact of offering renewing warranties on remanufactured products. Specifically, the paper suggests a methodology which simultaneously minimizes the cost incurred by the remanufacturers and maximizes the confidence of the consumers towards buying remanufacturing products. Design/methodology/approach: This study uses discrete-event simulation to optimize the implementation of a two-dimensional renewing warranty policy for remanufactured products. The implementation is illustrated using a specific product recovery system called the Advanced Remanufacturing-To-Order (ARTO) system. The experiments used in the study were designed using Taguchi’s Orthogonal Arrays to represent the entire domain of the recovery system so as to observe the system behavior under various experimental conditions. In order to determine the optimum strategy offered by the remanufacturer, various warranty and preventive maintenance scenarios were analyzed using pairwise t-tests along with one-way analysis of variance (ANOVA) and Tukey pairwise comparisons tests for every scenario. Findings: The proposed methodology is able to simultaneously minimize the cost incurred by the remanufacturer, optimize the warranty price and period, and optimize the preventive maintenance strategy resulting in increased consumer confidence. Originality/value: This is the first study that evaluates in a

  11. 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.

  12. [Examination of safety improvement by failure record analysis that uses reliability engineering].

    Science.gov (United States)

    Kato, Kyoichi; Sato, Hisaya; Abe, Yoshihisa; Ishimori, Yoshiyuki; Hirano, Hiroshi; Higashimura, Kyoji; Amauchi, Hiroshi; Yanakita, Takashi; Kikuchi, Kei; Nakazawa, Yasuo

    2010-08-20

    How the maintenance checks of the medical treatment system, including start of work check and the ending check, was effective for preventive maintenance and the safety improvement was verified. In this research, date on the failure of devices in multiple facilities was collected, and the data of the trouble repair record was analyzed by the technique of reliability engineering. An analysis of data on the system (8 general systems, 6 Angio systems, 11 CT systems, 8 MRI systems, 8 RI systems, and the radiation therapy system 9) used in eight hospitals was performed. The data collection period assumed nine months from April to December 2008. Seven items were analyzed. (1) Mean time between failures (MTBF) (2) Mean time to repair (MTTR) (3) Mean down time (MDT) (4) Number found by check in morning (5) Failure generation time according to modality. The classification of the breakdowns per device, the incidence, and the tendency could be understood by introducing reliability engineering. Analysis, evaluation, and feedback on the failure generation history are useful to keep downtime to a minimum and to ensure safety.

  13. Improved Reliability of Small Molecule Organic Solar Cells by Double Anode Buffer Layers

    Directory of Open Access Journals (Sweden)

    Pao-Hsun Huang

    2014-01-01

    Full Text Available An optimized hybrid planar heterojunction (PHJ of small molecule organic solar cells (SM-OSCs based on copper phthalocyanine (CuPc as donor and fullerene (C60 as acceptor was fabricated, which obviously enhanced the performance of device by sequentially using both MoO3 and pentacene as double anode buffer layers (ABL, also known as hole extraction layer (HEL. A series of the vacuum-deposited ABL, acting as an electron and exciton blocking layer, were examined for their characteristics in SM-OSCs. The performance and reliability were compared between conventional ITO/ABL/CuPc/C60/BCP/Ag cells and the new ITO/double ABL/CuPc/C60/BCP/Ag cells. The effect on the electrical properties of these materials was also investigated to obtain the optimal thickness of ABL. The comparison shows that the modified cell has an enhanced reliability compared to traditional cells. The improvement of lifetime was attributed to the idea of double layers to prevent humidity and oxygen from diffusing into the active layer. We demonstrated that the interfacial extraction layers are necessary to avoid degradation of device. That is to say, in normal temperature and pressure, a new avenue for the device within double buffer layers has exhibited the highest values of open circuit voltage (Voc, fill factor (FF, and lifetime in this work compared to monolayer of ABL.

  14. Control Strategies for Improving Energy Efficiency and Reliability in Autonomous Microgrids with Communication Constraints

    Directory of Open Access Journals (Sweden)

    Francisco Martins Portelinha Júnior

    2017-09-01

    Full Text Available Microgrids are a feasible path to deploy smart grids, an intelligent and highly automated power system. Their operation demands a dedicated communication infrastructure to manage, control and monitor the intermittent sources of energy and loads. Therefore, smart devices will be connected to support the growth of grid smartness increasing the dependency on communication networks, which consumes a high amount of power. In an energy-limited scenario, one of the main issues is to enhance the power supply time. Therefore, this paper proposes a hybrid methodology for microgrid energy management, integrated with a communication infrastructure to improve and to optimize islanded microgrid operation at maximum energy efficiency. The hybrid methodology applies some control management rules, such as intentional load shedding, priority load management, and communication energy saving. These energy saving rules establish a trade-off between increasing microgrid energy availability and communication system reliability. To achieve a compromised solution, a continuous time Markov chain model describes the impact of energy saving policies into system reliability. The proposed methodology is simulated and tested with the help of the modified IEEE 34 node test-system.

  15. Daily Readiness Huddles in Radiology-Improving Communication, Coordination, and Problem-Solving Reliability.

    Science.gov (United States)

    Donnelly, Lane F

    Deploying an intentional daily management process is a key part to create high-reliability culture. Key components described in the literature for a successfully daily management process include leadership standard work, visual controls, daily accountability processes, and the discipline to stick to the process over the long term. We believe that the institution of a daily readiness huddle has helped us better coordinate and communicate as a department and improved our ability to deliver imaging services on a daily basis. The daily readiness huddle has enabled us to more rapidly identify issues and has brought accountability to seeing solutions to those issues brought to fruition. In addition, it has helped with team building, including between the radiologists and the nonphysician staff. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Improving human reliability through better nuclear power plant system design: Program for advanced nuclear power studies

    International Nuclear Information System (INIS)

    Golay, M.W.

    1993-01-01

    The project on ''Development of a Theory of the Dependence of Human Reliability upon System Designs as a Means of Improving Nuclear Power Plant Performance'' was been undertaken in order to address the problem of human error in advanced nuclear power plant designs. Lack of a mature theory has retarded progress in reducing likely frequencies of human errors. Work being pursued in this project is to perform a set of experiments involving human subjects who are required to operate, diagnose and respond to changes in computer-simulated systems, relevant to those encountered in nuclear power plants, which are made to differ in complexity in a systematic manner. The computer program used to present the problems to be solved also records the response of the operator as it unfolds

  17. Reliability improvement for anisotropic biased compensated α/β contamination meter

    Energy Technology Data Exchange (ETDEWEB)

    Coulon, R., E-mail: romain.coulon@cea.fr [CEA, LIST, Laboratoire Capteurs et Architectures Electroniques, F-91191 Gif-sur-Yvette (France); Montagu, T. [CEA, LIST, Laboratoire de Modélisation et Simulation des Systèmes, F-91191 Gif-sur-Yvette (France); Schoepff, V. [CEA, LIST, Laboratoire Capteurs et Architectures Electroniques, F-91191 Gif-sur-Yvette (France); Menaa, N.; Ulmann, A. Gallozzi; Blanc de Lanaute, N. [CANBERRA France, F-78182 St Quentin en Yvelines (France)

    2016-11-21

    Nuclear instruments such as alpha/beta contamination meter are frequently used in a compensated mode where the contribution of gamma radiation background is compensated by a guard detector. The signal of interest is then the subtraction of counting from both channels. In practice, the noise signal measured by the guard detector is not strictly equal to the noise contribution into the first detector due to anisotropic biases. The random error (under Poisson assumption) is taken into account to build a hypothesis test. The system is also designed to minimize the systematic error but in some cases, this bias could not be completely removed. The measurement system then shows different behavior when the surrounding environment changes exhibiting inopportune false alarms. A method allowing the false alarms to be suppressed is addressed in this study for compensated measurement. An improvement in terms of reliability has been proven.

  18. Improved mechanical reliability of MEMS electret based vibration energy harvesters for automotive applications

    International Nuclear Information System (INIS)

    Renaud, M; Goedbloed, M; De Nooijer, C; Van Schaijk, R; Fujita, T

    2014-01-01

    Current commercial wireless tire pressure monitoring systems (TPMS) require a battery as electrical power source. The battery limits the lifetime of the TPMS. This limit can be circumvented by replacing the battery by a vibration energy harvester. Autonomous wireless TPMS powered by MEMS electret based vibration energy harvester have been demonstrated. A remaining technical challenge to attain the grade of commercial product with these autonomous TPMS is the mechanical reliability of the MEMS harvester. It should survive the harsh conditions imposed by the tire environment, particularly in terms of mechanical shocks. As shown in this article, our first generation of harvesters has a shock resilience of 400 g, which is far from being sufficient for the targeted application. In order to improve this aspect, several types of shock absorbing structures are investigated. With the best proposed solution, the shock resilience of the harvesters is brought above 2500 g

  19. Reducing Variability of Workforce as a Tool to Improve Plan Reliability

    DEFF Research Database (Denmark)

    Shen, Yicheng; Zygmunt, Katarzyna Julia; Wandahl, Søren

    2017-01-01

    Variability of flow is recognized as one of the greatest obstacles to production management. Since the work flow and labour flow are two dominators of work performance, it is important to manage them simultaneously. The objective of this paper is to examine if an increased plan reliability could...... of the workforce flow does not necessarily shorten the project length, nevertheless it increases probability to finish the tasks within a critical path duration. Additionally, it was concluded, that reducing the variance of crew allocation can improve the productivity....... be reached by reducing the variance of a labour flow. Therefore, three different construction labour data sets have been examined by utilizing Monte Carlo Simulation, to analyze the probability to finish simulated projects within a certain time. The research findings revealed that reducing variance...

  20. Advanced control systems to improve nuclear power plant reliability and efficiency

    International Nuclear Information System (INIS)

    1997-07-01

    The TECDOC is the result of a series of an advisory and consultants meetings held by the IAEA in 1995-1996 in Vienna (March 1995), in Erlangen Germany (December 1995), in Garching, Germany (June 1996) and in Vienna (November 1996). It was prepared with the participation and contributions of experts from Austria, Canada, Finland, France, Germany, the Republic of Korea, Norway, the Russian Federation, the United Kingdom and the United States of America. The publication not only describes advanced control systems for the improvement of nuclear power plant reliability and efficiency, but also provides a road map to guide interested readers to plan and execute an advanced instrumentation and control project. The subjects include: identification of needs and requirements, justification for safety and user acceptance, and the development of an engineering process. The report should be of interest to nuclear power plant staff, I and C system designers and integrators as well as regulators and researchers. Refs, figs, tabs

  1. INPO's role in the improvement of nuclear plant safety and reliability

    International Nuclear Information System (INIS)

    Pate, Z.T.

    1985-01-01

    The Institute of Nuclear Power Operations (INPO) is a nonprofit, nongovernment corporation dedicated to promoting safe and reliable operation and quality construction of nuclear power plants. The institute is supported by the US nuclear utility industry. All US utilities building or operating nuclear power plants are INPO members. INPO's many activities fall within four major program areas: (1) Evaluations: INPO conducts detailed evaluations of all US operating plants, utility corporate support of nuclear programs, and nuclear projects under active construction. Events analysis and information exchange: INPO reviews plant reports of abnormal or unusual events and reports the lessons learned to the industry. INPO also fosters improved industry communications through a worldwide telecommunications network. (3) Training and accreditation: INPO assists utilities, including international participants, in developing quality training programs; and (4) Assistance: the Institute provides various forms of assistance to members and participants. INPO places emphasis on visits to facilities to aid members and participants in various program or operational areas

  2. Some improvements on adaptive genetic algorithms for reliability-related applications

    International Nuclear Information System (INIS)

    Ye Zhisheng; Li Zhizhong; Xie Min

    2010-01-01

    Adaptive genetic algorithms (GAs) have been shown to be able to improve GA performance in reliability-related optimization studies. However, there are different ways to implement adaptive GAs, some of which are even in conflict with each other. In this study, a simple parameter-adjusting method using mean and variance of each generation is introduced. This method is used to compare two of such conflicting adaptive GA methods: GAs with increasing mutation rate and decreasing crossover rate and GAs with decreasing mutation rate and increasing crossover rate. The illustrative examples indicate that adaptive GAs with decreasing mutation rate and increasing crossover rate finally yield better results. Furthermore, a population disturbance method is proposed to avoid local optimum solutions. This idea is similar to exotic migration to a tribal society. To solve the problem of large solution space, a variable roughening method is also embedded into GA. Two case studies are presented to demonstrate the effectiveness of the proposed method.

  3. Improving the Reliability of LDP through the Divergence of Power Supply for LDP

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Bang Sil [KHNP CRI, Daejeon (Korea, Republic of)

    2016-10-15

    The representative operating systems are Large Display Panel (LDP), Operator Workstation (OWS), Computerized Procedure System (CPS). The LDP provides the information which is plant essential safety function, plant operating mode, the state of major operating variable and the important alarm to operator continuously. In case of malfunction and switchover fail of the inverter, it is possible to occur the power loss of LDP. The power of LDP and operator console workstation had been supplied by only 2 non-safety Power Line1/Power Line2 (P.L1/P.L2). This study mentioned the divergence of power for LDP as method of power loss caused by unreliability of inverter. Ultimately, LDP power line has been added, and then it is more improved on the safety of LDP operation than before. So Shin-Kori 3,4 can enhance the reliability and economic, safety of plant.

  4. Some improvements on adaptive genetic algorithms for reliability-related applications

    Energy Technology Data Exchange (ETDEWEB)

    Ye Zhisheng, E-mail: yez@nus.edu.s [Department of Industrial and Systems Engineering, National University of Singapore, Singapore 119 260 (Singapore); Li Zhizhong [Department of Industrial Engineering, Tsinghua University, beijing 100084 (China); Xie Min [Department of Industrial and Systems Engineering, National University of Singapore, Singapore 119 260 (Singapore)

    2010-02-15

    Adaptive genetic algorithms (GAs) have been shown to be able to improve GA performance in reliability-related optimization studies. However, there are different ways to implement adaptive GAs, some of which are even in conflict with each other. In this study, a simple parameter-adjusting method using mean and variance of each generation is introduced. This method is used to compare two of such conflicting adaptive GA methods: GAs with increasing mutation rate and decreasing crossover rate and GAs with decreasing mutation rate and increasing crossover rate. The illustrative examples indicate that adaptive GAs with decreasing mutation rate and increasing crossover rate finally yield better results. Furthermore, a population disturbance method is proposed to avoid local optimum solutions. This idea is similar to exotic migration to a tribal society. To solve the problem of large solution space, a variable roughening method is also embedded into GA. Two case studies are presented to demonstrate the effectiveness of the proposed method.

  5. Efforts to improve safety and reliability of nuclear power plants in Kyushu Electric Power

    International Nuclear Information System (INIS)

    Yamamoto, Satoshi

    2014-01-01

    After the Fukushima accident, Kyushu Electric Power Co. took emergency safety measures requested by government to ensure power supply, coolant supply pumps and cooling water so as to keep cooling fuels in the reactor and spent fuel storage pool in case of losses of ordinary cooling capability caused by earthquake and tsunami. In order to improve safety and reliability of nuclear power plants, further efforts based on lessons learned from the Fukushima accident had been made to diversify corresponding equipment of safety measures in terms of prevention of core damage, prevention of containment failure, mitigation of radioactive materials release, cooling of spent fuel pit and ensurance of power supply, and to enhance emergency response capability so as to make operational management more complete. Additional safety measures applicable to new regulatory requirements against severe accidents were in progress. This article introduced details of such activities. (T. Tanaka)

  6. Advanced control systems to improve nuclear power plant reliability and efficiency

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-07-01

    The TECDOC is the result of a series of an advisory and consultants meetings held by the IAEA in 1995-1996 in Vienna (March 1995), in Erlangen Germany (December 1995), in Garching, Germany (June 1996) and in Vienna (November 1996). It was prepared with the participation and contributions of experts from Austria, Canada, Finland, France, Germany, the Republic of Korea, Norway, the Russian Federation, the United Kingdom and the United States of America. The publication not only describes advanced control systems for the improvement of nuclear power plant reliability and efficiency, but also provides a road map to guide interested readers to plan and execute an advanced instrumentation and control project. The subjects include: identification of needs and requirements, justification for safety and user acceptance, and the development of an engineering process. The report should be of interest to nuclear power plant staff, I and C system designers and integrators as well as regulators and researchers. Refs, figs, tabs.

  7. A Method for Improving Reliability of Radiation Detection using Deep Learning Framework

    International Nuclear Information System (INIS)

    Chang, Hojong; Kim, Tae-Ho; Han, Byunghun; Kim, Hyunduk; Kim, Ki-duk

    2017-01-01

    Radiation detection is essential technology for overall field of radiation and nuclear engineering. Previously, technology for radiation detection composes of preparation of the table of the input spectrum to output spectrum in advance, which requires simulation of numerous predicted output spectrum with simulation using parameters modeling the spectrum. In this paper, we propose new technique to improve the performance of radiation detector. The software in the radiation detector has been stagnant for a while with possible intrinsic error of simulation. In the proposed method, to predict the input source using output spectrum measured by radiation detector is performed using deep neural network. With highly complex model, we expect that the complex pattern between data and the label can be captured well. Furthermore, the radiation detector should be calibrated regularly and beforehand. We propose a method to calibrate radiation detector using GAN. We hope that the power of deep learning may also reach to radiation detectors and make huge improvement on the field. Using improved radiation detector, the reliability of detection would be confident, and there are many tasks remaining to solve using deep learning in nuclear engineering society.

  8. Improving the Test-Retest Reliability of Resting State fMRI by Removing the Impact of Sleep.

    Science.gov (United States)

    Wang, Jiahui; Han, Junwei; Nguyen, Vinh T; Guo, Lei; Guo, Christine C

    2017-01-01

    Resting state functional magnetic resonance imaging (rs-fMRI) provides a powerful tool to examine large-scale neural networks in the human brain and their disturbances in neuropsychiatric disorders. Thanks to its low demand and high tolerance, resting state paradigms can be easily acquired from clinical population. However, due to the unconstrained nature, resting state paradigm is associated with excessive head movement and proneness to sleep. Consequently, the test-retest reliability of rs-fMRI measures is moderate at best, falling short of widespread use in the clinic. Here, we characterized the effect of sleep on the test-retest reliability of rs-fMRI. Using measures of heart rate variability (HRV) derived from simultaneous electrocardiogram (ECG) recording, we identified portions of fMRI data when subjects were more alert or sleepy, and examined their effects on the test-retest reliability of functional connectivity measures. When volumes of sleep were excluded, the reliability of rs-fMRI is significantly improved, and the improvement appears to be general across brain networks. The amount of improvement is robust with the removal of as much as 60% volumes of sleepiness. Therefore, test-retest reliability of rs-fMRI is affected by sleep and could be improved by excluding volumes of sleepiness as indexed by HRV. Our results suggest a novel and practical method to improve test-retest reliability of rs-fMRI measures.

  9. Improving the Test-Retest Reliability of Resting State fMRI by Removing the Impact of Sleep

    Directory of Open Access Journals (Sweden)

    Jiahui Wang

    2017-05-01

    Full Text Available Resting state functional magnetic resonance imaging (rs-fMRI provides a powerful tool to examine large-scale neural networks in the human brain and their disturbances in neuropsychiatric disorders. Thanks to its low demand and high tolerance, resting state paradigms can be easily acquired from clinical population. However, due to the unconstrained nature, resting state paradigm is associated with excessive head movement and proneness to sleep. Consequently, the test-retest reliability of rs-fMRI measures is moderate at best, falling short of widespread use in the clinic. Here, we characterized the effect of sleep on the test-retest reliability of rs-fMRI. Using measures of heart rate variability (HRV derived from simultaneous electrocardiogram (ECG recording, we identified portions of fMRI data when subjects were more alert or sleepy, and examined their effects on the test-retest reliability of functional connectivity measures. When volumes of sleep were excluded, the reliability of rs-fMRI is significantly improved, and the improvement appears to be general across brain networks. The amount of improvement is robust with the removal of as much as 60% volumes of sleepiness. Therefore, test-retest reliability of rs-fMRI is affected by sleep and could be improved by excluding volumes of sleepiness as indexed by HRV. Our results suggest a novel and practical method to improve test-retest reliability of rs-fMRI measures.

  10. Shock reliability analysis and improvement of MEMS electret-based vibration energy harvesters

    International Nuclear Information System (INIS)

    Renaud, M; Goedbloed, M; De Nooijer, C; Van Schaijk, R; Fujita, T

    2015-01-01

    Vibration energy harvesters can serve as a replacement solution to batteries for powering tire pressure monitoring systems (TPMS). Autonomous wireless TPMS powered by microelectromechanical system (MEMS) electret-based vibration energy harvester have been demonstrated. The mechanical reliability of the MEMS harvester still has to be assessed in order to bring the harvester to the requirements of the consumer market. It should survive the mechanical shocks occurring in the tire environment. A testing procedure to quantify the shock resilience of harvesters is described in this article. Our first generation of harvesters has a shock resilience of 400 g, which is far from being sufficient for the targeted application. In order to improve this aspect, the first important aspect is to understand the failure mechanism. Failure is found to occur in the form of fracture of the device’s springs. It results from impacts between the anchors of the springs when the harvester undergoes a shock. The shock resilience of the harvesters can be improved by redirecting these impacts to nonvital parts of the device. With this philosophy in mind, we design three types of shock absorbing structures and test their effect on the shock resilience of our MEMS harvesters. The solution leading to the best results consists of rigid silicon stoppers covered by a layer of Parylene. The shock resilience of the harvesters is brought above 2500 g. Results in the same range are also obtained with flexible silicon bumpers, which are simpler to manufacture. (paper)

  11. The experiences to improve plant performance and reliability of Ko-Ri nuclear power plants

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Ho Weon [Korea Electric Power Corp. Ko-Ri nuclear power division, Ko-Ri (Korea, Republic of)

    1998-07-01

    This paper provides a discussion of the lessons learned from operational experience and the future plans to improve performance of the Ko-Ri plant. To operate nuclear power plants safely with good performance is the only way to mitigate the negative image of nuclear power generation to the public and to enhance the economical benefit compared to other electrical generation method. Therefore, in a continuous effort to overcome a negative challenge from outside, we have driven an aggressive 'OCTF' campaign as part of safety. As a result of our efforts, the following remarkable achievements have been accomplished. (1) 3 times of OCTF during recent three years (2) Selected twice as a top notch power plant on the list of NEI magazine in terms of plant capacity factor (3) No scram recorded in 1997 for all 4 units at Ko-Ri site. Ko-Ri is now undergoing the large scale plant betterment projects for retaking-off our operating performance to the level of new challenge target. Such improvement of critical components in the reactor coolant system and turbine system greatly contribute to increase the safety and reliability of the plant and to shortening of the planned outage period as well as to reduction of radiation exposure and radwaste. (Cho, G. S.). 5 tabs., 10 figs.

  12. Shock reliability analysis and improvement of MEMS electret-based vibration energy harvesters

    Science.gov (United States)

    Renaud, M.; Fujita, T.; Goedbloed, M.; de Nooijer, C.; van Schaijk, R.

    2015-10-01

    Vibration energy harvesters can serve as a replacement solution to batteries for powering tire pressure monitoring systems (TPMS). Autonomous wireless TPMS powered by microelectromechanical system (MEMS) electret-based vibration energy harvester have been demonstrated. The mechanical reliability of the MEMS harvester still has to be assessed in order to bring the harvester to the requirements of the consumer market. It should survive the mechanical shocks occurring in the tire environment. A testing procedure to quantify the shock resilience of harvesters is described in this article. Our first generation of harvesters has a shock resilience of 400 g, which is far from being sufficient for the targeted application. In order to improve this aspect, the first important aspect is to understand the failure mechanism. Failure is found to occur in the form of fracture of the device’s springs. It results from impacts between the anchors of the springs when the harvester undergoes a shock. The shock resilience of the harvesters can be improved by redirecting these impacts to nonvital parts of the device. With this philosophy in mind, we design three types of shock absorbing structures and test their effect on the shock resilience of our MEMS harvesters. The solution leading to the best results consists of rigid silicon stoppers covered by a layer of Parylene. The shock resilience of the harvesters is brought above 2500 g. Results in the same range are also obtained with flexible silicon bumpers, which are simpler to manufacture.

  13. Carbohydrate ingestion improves performance of a new reliable test of soccer performance.

    Science.gov (United States)

    Currell, Kevin; Conway, Steve; Jeukendrup, Asker E

    2009-02-01

    The aim of the study was to investigate the reliability of a new test of soccer performance and evaluate the effect of carbohydrate (CHO) on soccer performance. Eleven university footballers were recruited and underwent 3 trials in a randomized order. Two of the trials involved ingesting a placebo beverage, and the other, a 7.5% maltodextrin solution. The protocol comprised a series of ten 6-min exercise blocks on an outdoor Astroturf pitch, separated by the performance of 2 of the 4 soccer-specific tests, making the protocol 90 min in duration. The intensity of the exercise was designed to be similar to the typical activity pattern during soccer match play. Participants performed skill tests of dribbling, agility, heading, and shooting throughout the protocol. The coefficients of variation for dribbling, agility, heading, and shooting were 2.2%, 1.2%, 7.0%, and 2.8%, respectively. The mean combined placebo scores were 42.4 +/- 2.7 s, 43.1 +/- 3.7 s, 210 +/- 34 cm, and 212 +/- 17 points for agility, dribbling, heading, and kicking, respectively. CHO ingestion led to a combined agility time of 41.5 +/- 0.8 s, for dribbling 41.7 +/- 3.5 s, 213 +/- 11 cm for heading, and 220 +/- 5 points for kicking accuracy. There was a significant improvement in performance for dribbling, agility, and shooting (p soccer performance, and ingesting CHO leads to an improvement in soccer performance.

  14. The experiences to improve plant performance and reliability of Ko-Ri nuclear power plants

    International Nuclear Information System (INIS)

    Kang, Ho Weon

    1998-01-01

    This paper provides a discussion of the lessons learned from operational experience and the future plans to improve performance of the Ko-Ri plant. To operate nuclear power plants safely with good performance is the only way to mitigate the negative image of nuclear power generation to the public and to enhance the economical benefit compared to other electrical generation method. Therefore, in a continuous effort to overcome a negative challenge from outside, we have driven an aggressive 'OCTF' campaign as part of safety. As a result of our efforts, the following remarkable achievements have been accomplished. (1) 3 times of OCTF during recent three years (2) Selected twice as a top notch power plant on the list of NEI magazine in terms of plant capacity factor (3) No scram recorded in 1997 for all 4 units at Ko-Ri site. Ko-Ri is now undergoing the large scale plant betterment projects for retaking-off our operating performance to the level of new challenge target. Such improvement of critical components in the reactor coolant system and turbine system greatly contribute to increase the safety and reliability of the plant and to shortening of the planned outage period as well as to reduction of radiation exposure and radwaste. (Cho, G. S.). 5 tabs., 10 figs

  15. Increased scientific rigor will improve reliability of research and effectiveness of management

    Science.gov (United States)

    Sells, Sarah N.; Bassing, Sarah B.; Barker, Kristin J.; Forshee, Shannon C.; Keever, Allison; Goerz, James W.; Mitchell, Michael S.

    2018-01-01

    Rigorous science that produces reliable knowledge is critical to wildlife management because it increases accurate understanding of the natural world and informs management decisions effectively. Application of a rigorous scientific method based on hypothesis testing minimizes unreliable knowledge produced by research. To evaluate the prevalence of scientific rigor in wildlife research, we examined 24 issues of the Journal of Wildlife Management from August 2013 through July 2016. We found 43.9% of studies did not state or imply a priori hypotheses, which are necessary to produce reliable knowledge. We posit that this is due, at least in part, to a lack of common understanding of what rigorous science entails, how it produces more reliable knowledge than other forms of interpreting observations, and how research should be designed to maximize inferential strength and usefulness of application. Current primary literature does not provide succinct explanations of the logic behind a rigorous scientific method or readily applicable guidance for employing it, particularly in wildlife biology; we therefore synthesized an overview of the history, philosophy, and logic that define scientific rigor for biological studies. A rigorous scientific method includes 1) generating a research question from theory and prior observations, 2) developing hypotheses (i.e., plausible biological answers to the question), 3) formulating predictions (i.e., facts that must be true if the hypothesis is true), 4) designing and implementing research to collect data potentially consistent with predictions, 5) evaluating whether predictions are consistent with collected data, and 6) drawing inferences based on the evaluation. Explicitly testing a priori hypotheses reduces overall uncertainty by reducing the number of plausible biological explanations to only those that are logically well supported. Such research also draws inferences that are robust to idiosyncratic observations and

  16. Improved reliability, accuracy and quality in automated NMR structure calculation with ARIA

    Energy Technology Data Exchange (ETDEWEB)

    Mareuil, Fabien [Institut Pasteur, Cellule d' Informatique pour la Biologie (France); Malliavin, Thérèse E.; Nilges, Michael; Bardiaux, Benjamin, E-mail: bardiaux@pasteur.fr [Institut Pasteur, Unité de Bioinformatique Structurale, CNRS UMR 3528 (France)

    2015-08-15

    In biological NMR, assignment of NOE cross-peaks and calculation of atomic conformations are critical steps in the determination of reliable high-resolution structures. ARIA is an automated approach that performs NOE assignment and structure calculation in a concomitant manner in an iterative procedure. The log-harmonic shape for distance restraint potential and the Bayesian weighting of distance restraints, recently introduced in ARIA, were shown to significantly improve the quality and the accuracy of determined structures. In this paper, we propose two modifications of the ARIA protocol: (1) the softening of the force field together with adapted hydrogen radii, which is meaningful in the context of the log-harmonic potential with Bayesian weighting, (2) a procedure that automatically adjusts the violation tolerance used in the selection of active restraints, based on the fitting of the structure to the input data sets. The new ARIA protocols were fine-tuned on a set of eight protein targets from the CASD–NMR initiative. As a result, the convergence problems previously observed for some targets was resolved and the obtained structures exhibited better quality. In addition, the new ARIA protocols were applied for the structure calculation of ten new CASD–NMR targets in a blind fashion, i.e. without knowing the actual solution. Even though optimisation of parameters and pre-filtering of unrefined NOE peak lists were necessary for half of the targets, ARIA consistently and reliably determined very precise and highly accurate structures for all cases. In the context of integrative structural biology, an increasing number of experimental methods are used that produce distance data for the determination of 3D structures of macromolecules, stressing the importance of methods that successfully make use of ambiguous and noisy distance data.

  17. 75 FR 36271 - Real Estate Settlement Procedures Act (RESPA): Home Warranty Companies' Payments to Real Estate...

    Science.gov (United States)

    2010-06-25

    ... Estate Settlement Procedures Act (RESPA): Home Warranty Companies' Payments to Real Estate Brokers and... RESPA and HUD's implementing RESPA regulations, services performed by real estate brokers and agents as additional settlement services in a real estate transaction are compensable if the services are actual...

  18. 40 CFR 85.2110 - Submission of owners' manuals and warranty statements to EPA.

    Science.gov (United States)

    2010-07-01

    ... AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF AIR POLLUTION FROM MOBILE SOURCES Emissions Control System Performance Warranty Regulations and Voluntary Aftermarket Part Certification Program § 85... manufacturer may submit the most recent draft at that time, provided that final versions are submitted within...

  19. Optimizing the warranty period by cuckoo meta-heuristic algorithm in heterogeneous customers' population

    Science.gov (United States)

    Roozitalab, Ali; Asgharizadeh, Ezzatollah

    2013-12-01

    Warranty is now an integral part of each product. Since its length is directly related to the cost of production, it should be set in such a way that it would maximize revenue generation and customers' satisfaction. Furthermore, based on the behavior of customers, it is assumed that increasing the warranty period to earn the trust of more customers leads to more sales until the market is saturated. We should bear in mind that different groups of consumers have different consumption behaviors and that performance of the product has a direct impact on the failure rate over the life of the product. Therefore, the optimum duration for every group is different. In fact, we cannot present different warranty periods for various customer groups. In conclusion, using cuckoo meta-heuristic optimization algorithm, we try to find a common period for the entire population. Results with high convergence offer a term length that will maximize the aforementioned goals simultaneously. The study was tested using real data from Appliance Company. The results indicate a significant increase in sales when the optimization approach was applied; it provides a longer warranty through increased revenue from selling, not only reducing profit margins but also increasing it.

  20. 76 FR 33166 - Defense Federal Acquisition Regulation Supplement (DFARS); Warranty Tracking of Serialized Items...

    Science.gov (United States)

    2011-06-08

    ... traceability of items to a warranty will assist all members of the supply chain to manage risk appropriately. This traceability also leads to ensuring the Government receives the supplies purchased, reducing the... Acquisition, Technology and Logistics dated February 6, 2007, which required definition of the requirements to...

  1. 40 CFR 85.1510 - Maintenance instructions, warranties, emission labeling and fuel economy requirements.

    Science.gov (United States)

    2010-07-01

    ..., emission labeling and fuel economy requirements. 85.1510 Section 85.1510 Protection of Environment..., warranties, emission labeling and fuel economy requirements. The provisions of this section are applicable to... for final admission. (d) Fuel economy labeling. (1) The certificate holder shall affix a fuel economy...

  2. How Case-Based Reasoning on e-Community Knowledge Can Be Improved Thanks to Knowledge Reliability

    OpenAIRE

    Gaillard , Emmanuelle; Lieber , Jean; Nauer , Emmanuel; Cordier , Amélie

    2014-01-01

    International audience; This paper shows that performing case-based reasoning (CBR) on knowledge coming from an e-community is improved by taking into account knowledge reliability. MKM (meta-knowledge model) is a model for managing reliability of the knowledge units that are used in the reasoning process. For this, MKM uses meta-knowledge such as belief, trust and reputation, about knowledge units and users. MKM is used both to select relevant knowledge to conduct the reasoning process, and ...

  3. Improving the reliability of the prognosis of radiation exposures using data assimilation

    International Nuclear Information System (INIS)

    Twenhoefel, C.J.W.; Eleveld, H.

    2003-01-01

    Full text: During large-scale nuclear accidents quantitative risk estimates usually underlie a countermeasure strategy. Because of the overwhelming social and economical impact of countermeasures not only the speed but also the reliability of the underlying calculations are of prime importance. Real-time atmospheric dispersion models are an important tool to support the decision-makers with spatial and temporal information on the dispersion forecast and the extent of the expected contamination. Due to the stochastic and chaotic nature of the atmosphere the real-time calculation of air dispersion is quite complicated. The accuracy of the calculated spatial and temporal distributions of air concentration, deposition and the corresponding radiation levels is limited due to uncertainties in the applied dispersion algorithms, limitations in knowledge and availability of atmospheric input data and knowledge of the release and the release conditions during an emergency. To improve the prognosis of the radiation exposure it is envisaged to use the on-line data of the National Radioactivity Monitoring Network. In a first step the monitored gamma radiation levels are related to the calculated external radiation levels from source term estimates based on the plant status. In the next step both the results of air dispersion model calculations and the data of the monitoring network are compared using RIVM's dispersion model validation tool [1-2]. From this a quantitative measure for the agreement between a model run and a particular measurement set can be deduced. This will be followed by a data assimilation technique based an RIVM's validation tool which provides an improved reliability of the prognosis when compared to intermediate, i.e. previous model runs. An uncertainty and sensitivity analysis of the air dispersion model must identify the relevant input parameters. In the absence of elevated levels on our monitoring network the Kincaid data set will be used to demonstrate

  4. Improving Reliability of Embedded Systems through Dynamic Memory Manager Optimization using Grammatical Evolution

    OpenAIRE

    Colmenar, J. Manuel; Risco-Martin, Jose L.; Atienza Alonso, David; Garnica, Oscar; Hidalgo, Jose I.; Lanchares, Juan

    2010-01-01

    Technology scaling has offered advantages to embedded systems, such as increased performance, more available memory and reduced energy consumption. However, scaling also brings a number of problems like reliability degradation mechanisms. The intensive activity of devices and high operating temperatures are key factors for reliability degradation in latest technology nodes. Focusing on embedded systems, the memory is prone to suffer reliability problems due to the intensive use of dynamic mem...

  5. Embedded Sensors and Controls to Improve Component Performance and Reliability: Conceptual Design Report

    Energy Technology Data Exchange (ETDEWEB)

    Kisner, Roger A [ORNL; Melin, Alexander M [ORNL; Burress, Timothy A [ORNL; Fugate, David L [ORNL; Holcomb, David Eugene [ORNL; Wilgen, John B [ORNL; Miller, John M [ORNL; Wilson, Dane F [ORNL; Silva, Pamela C [ORNL; Whitlow, Lynsie J [ORNL; Peretz, Fred J [ORNL

    2012-10-01

    The overall project objective is to demonstrate improved reliability and increased performance made possible by deeply embedding instrumentation and controls (I&C) in nuclear power plant components. The project is employing a highly instrumented canned rotor, magnetic bearing, fluoride salt pump as its I&C technology demonstration vehicle. The project s focus is not primarily on pump design, but instead is on methods to deeply embed I&C within a pump system. However, because the I&C is intimately part of the basic millisecond-by-millisecond functioning of the pump, the I&C design cannot proceed in isolation from the other aspects of the pump. The pump will not function if the characteristics of the I&C are not embedded within the design because the I&C enables performance of the basic function rather than merely monitoring quasi-stable performance. Traditionally, I&C has been incorporated in nuclear power plant (NPP) components after their design is nearly complete; adequate performance was obtained through over-design. This report describes the progress and status of the project and provides a conceptual design overview for the embedded I&C pump.

  6. Virtualization of Legacy Instrumentation Control Computers for Improved Reliability, Operational Life, and Management.

    Science.gov (United States)

    Katz, Jonathan E

    2017-01-01

    Laboratories tend to be amenable environments for long-term reliable operation of scientific measurement equipment. Indeed, it is not uncommon to find equipment 5, 10, or even 20+ years old still being routinely used in labs. Unfortunately, the Achilles heel for many of these devices is the control/data acquisition computer. Often these computers run older operating systems (e.g., Windows XP) and, while they might only use standard network, USB or serial ports, they require proprietary software to be installed. Even if the original installation disks can be found, it is a burdensome process to reinstall and is fraught with "gotchas" that can derail the process-lost license keys, incompatible hardware, forgotten configuration settings, etc. If you have running legacy instrumentation, the computer is the ticking time bomb waiting to put a halt to your operation.In this chapter, I describe how to virtualize your currently running control computer. This virtualized computer "image" is easy to maintain, easy to back up and easy to redeploy. I have used this multiple times in my own lab to greatly improve the robustness of my legacy devices.After completing the steps in this chapter, you will have your original control computer as well as a virtual instance of that computer with all the software installed ready to control your hardware should your original computer ever be decommissioned.

  7. Improving accuracy and reliability of 186-keV measurements for unattended enrichment monitoring

    International Nuclear Information System (INIS)

    Ianakiev, Kiril D.; Boyer, Brian D.; Swinhoe, Martyn T.; Moss, Cal E.; Goda, Joetta M.; Favalli, Andrea; Lombardi, Marcie; Paffet, Mark T.; Hill, Thomas R.; MacArthur, Duncan W.; Smith, Morag K.

    2010-01-01

    Improving the quality of safeguards measurements at Gas Centrifuge Enrichment Plants (GCEPs), whilst reducing the inspection effort, is an important objective given the number of existing and new plants that need to be safeguarded. A useful tool in many safeguards approaches is the on-line monitoring of enrichment in process pipes. One aspect of this measurement is a simple, reliable and precise passive measurement of the 186-keV line from 235 U. (The other information required is the amount of gas in the pipe. This can be obtained by transmission measurements or pressure measurements). In this paper we describe our research efforts towards such a passive measurement system. The system includes redundant measurements of the 186-keV line from the gas and separately from the wall deposits. The design also includes measures to reduce the effect of the potentially important background. Such an approach would practically eliminate false alarms and can maintain the operation of the system even with a hardware malfunction in one of the channels. The work involves Monte Carlo modeling and the construction of a proof-of-principle prototype. We will carry out experimental tests with UF 6 gas in pipes with and without deposits in order to demonstrate the deposit correction.

  8. Improvements in valve reliability due to implementation of effective condition monitoring programs

    International Nuclear Information System (INIS)

    Hale, Stan

    2003-01-01

    Modern diagnostic systems for motor-operated valves, pneumatic control valves and checkvalves have facilitated a shift in the maintenance philosophy for valves and actuators in nuclear power plants from schedule based to condition-based maintenance (CBM). This shift enables plant management to focus resources and schedule priority on the plant equipment that warrants attention thereby not wasting resources or increasing the human factors risk on equipment that has not degraded. The most recent initiatives combine condition monitoring with risk/safety insights to focus attention and resonances on the right equipment at the right time consistent with each component's safety-significance. The activities of the ASME working groups responsible for nuclear O and M codes have kept pace with the technology and process improvements necessary to maximize the technical and economic benefits of condition based and risk informed maintenance. This paper discusses adoption of valve condition monitoring in the nuclear power industry, changes to ASME codes and standards during the 90's to facilitate adoption of condition monitoring technology for in-service testing and recent efforts to combine risk insights with condition monitoring strategies to achieve the highest level of valve reliability and nuclear safety without over inflating maintenance cost. (author)

  9. Ambipolarity reduction in DMG asymmetric vacuum dielectric Schottky Barrier GAA MOSFET to improve hot carrier reliability

    Science.gov (United States)

    Kumar, Manoj; Haldar, Subhasis; Gupta, Mridula; Gupta, R. S.

    2017-11-01

    An explicit surface potential and subthreshold current model for novel Dual Metal Gate (DMG) Asymmetric Vacuum (AV) as gate dielectric Schottky Barrier (SB) Cylindrical Gate All Around (CGAA) MOSFET with the incorporation of localized charges (Nf) is developed to provide excellent immunity against threshold voltage (Vth) degradation due to hot carriers. Hot carrier induced Localized Charges (LC) either positive or negative leads to degrade the threshold of the device. The major advantage of the proposed DMG-AV-SB-CGAA MOSFET is that it mitigates the ambipolar behavior thus offering very good on current to off current ratio; and also reduces the electron temperature which leads to less hot carrier generation thus lesser degradation in Vth and improved Hot Carrier reliability. The surface potential is determined for three different regions by solving 1-D Poisson's and 2-D Laplace equation through separation of variable method to facilitate an optimal model for calculating the subthreshold drain current from Si-SiO2 interface boundary. The developed model results are in good agreement with that of ATLAS-TCAD simulation.

  10. Improving motor reliability in nuclear power plants: Volume 1, Performance evaluation and maintenance practices

    International Nuclear Information System (INIS)

    Subudhi, M.; Gunther, W.E.; Taylor, J.H.; Sugarman, A.C.; Sheets, M.W.

    1987-11-01

    This report constitutes the first of the three volumes under this NUREG. The report presents recommendations for developing a cost-effective program for performance evaluation and maintenance of electric motors in nuclear power plants. These recommendations are based on current industry practices, available techniques for monitoring degradation in motor components, manufacturer's recommendations, operating experience, and results from two laboratory tests on aged motors. Two laboratory test reports on a small and a large motor are presented in separate volumes of this NUREG. These provide the basis for the various functional indicators recommended for maintenance programs in this report. The overall preventive maintenance program is separated into two broad areas of activity aimed at mitigating the potential effects of equipment aging: Performance Evaluation and Equipment Maintenance. The latter involves actually maintaining the condition of the equipment while the former involves those activities undertaken to monitor degradation due to aging. These monitoring methods are further categorized into periodic testing, surveillance testing, continuous monitoring and inspections. This study focuses on the methods and procedures for performing the above activities to maintain the motors operationally ready in a nuclear facility. This includes an assessment of various functional indicators to determine their suitability for trending to monitor motor component condition. The intrusiveness of test methods and the present state-of-the-art for using the test equipment in a plant environment are discussed. In conclusion, implementation of the information provided in this report, will improve motor reliability in nuclear power plants. The study indicates the kinds of tests to conduct, how and when to conduct them, and to which motors the tests should be applied. 44 refs., 12 figs., 13 tabs

  11. Reliability-Based Design Optimization of Trusses with Linked-Discrete Design Variables using the Improved Firefly Algorithm

    Directory of Open Access Journals (Sweden)

    N. M. Okasha

    2016-04-01

    Full Text Available In this paper, an approach for conducting a Reliability-Based Design Optimization (RBDO of truss structures with linked-discrete design variables is proposed. The sections of the truss members are selected from the AISC standard tables and thus the design variables that represent the properties of each section are linked. Latin hypercube sampling is used in the evaluation of the structural reliability. The improved firefly algorithm is used for the optimization solution process. It was found that in order to use the improved firefly algorithm for efficiently solving problems of reliability-based design optimization with linked-discrete design variables; it needs to be modified as proposed in this paper to accelerate its convergence.

  12. Improving electrical power systems reliability through locally controlled distributed curtailable load

    Science.gov (United States)

    Dehbozorgi, Mohammad Reza

    2000-10-01

    Improvements in power system reliability have always been of interest to both power companies and customers. Since there are no sizable electrical energy storage elements in electrical power systems, the generated power should match the load demand at any given time. Failure to meet this balance may cause severe system problems, including loss of generation and system blackouts. This thesis proposes a methodology which can respond to either loss of generation or loss of load. It is based on switching of electric water heaters using power system frequency as the controlling signal. The proposed methodology encounters, and the thesis has addressed, the following associated problems. The controller must be interfaced with the existing thermostat control. When necessary to switch on loads, the water in the tank should not be overheated. Rapid switching of blocks of load, or chattering, has been considered. The contributions of the thesis are: (A) A system has been proposed which makes a significant portion of the distributed loads connected to a power system to behave in a predetermined manner to improve the power system response during disturbances. (B) The action of the proposed system is transparent to the customers. (C) The thesis proposes a simple analysis for determining the amount of such loads which might be switched and relates this amount to the size of the disturbances which can occur in the utility. (D) The proposed system acts without any formal communication links, solely using the embedded information present system-wide. (E) The methodology of the thesis proposes switching of water heater loads based on a simple, localized frequency set-point controller. The thesis has identified the consequent problem of rapid switching of distributed loads, which is referred to as chattering. (F) Two approaches have been proposed to reduce chattering to tolerable levels. (G) A frequency controller has been designed and built according to the specifications required to

  13. Follow-up of CT-derived airway wall thickness : Correcting for changes in inspiration level improves reliability

    NARCIS (Netherlands)

    Pompe, Esther; van Rikxoort, Eva M; Mets, Onno M; Charbonnier, Jean-Paul; Kuhnigk, Jan-Martin; de Koning, Harry J; Oudkerk, Matthijs; Vliegenthart, Rozemarijn; Zanen, Pieter; Lammers, Jan-Willem J; van Ginneken, Bram; de Jong, Pim A; Mohamed Hoesein, Firdaus A A

    2016-01-01

    OBJECTIVES: Airway wall thickness (AWT) is affected by changes in lung volume. This study evaluated whether correcting AWT on computed tomography (CT) for differences in inspiration level improves measurement agreement, reliability, and power to detect changes over time. METHODS: Participants of the

  14. Follow-up of CT-derived airway wall thickness : Correcting for changes in inspiration level improves reliability

    NARCIS (Netherlands)

    Pompe, Esther; van Rikxoort, Eva M.; Mets, Onno M.; Charbonnier, Jean-Paul; Kuhnigk, Jan-Martin; de Koning, Harry J.; Oudkerk, Matthijs; Vliegenthart, Rozemarijn; Zanen, Pieter; Lammers, Jan-Willem J.; van Ginneken, Bram; de Jong, Pim A.; Hoesein, Firdaus A. A. Mohamed

    2016-01-01

    Objectives: Airway wall thickness (AWT) is affected by changes in lung volume. This study evaluated whether correcting AWT on computed tomography (CT) for differences in inspiration level improves measurement agreement, reliability, and power to detect changes over time. Methods: Participants of the

  15. Improvement in reliability and accuracy of heater tube eddy current testing by integration with an appropriate destructive test

    International Nuclear Information System (INIS)

    Giovanelli, F.; Gabiccini, S.; Tarli, R.; Motta, P.

    1988-01-01

    A specially developed destructive test is described showing how the reliability and accuracy of a non-destructive technique can be improved if it is suitably accompanied by an appropriate destructive test. The experiment was carried out on samples of AISI 304L tubes from the low-pressure (LP) preheaters of a BWR 900 MW nuclear plant. (author)

  16. Extended warranties, maintenance service and lease contracts modeling and analysis for decision-making

    CERN Document Server

    Murthy, D N Prabhakar

    2014-01-01

    Serving to unify the existing literature on extended warranties, maintenance service contracts and lease contracts, this book also presents a unique perspective on the topic focussed on cost analysis and decision-making from the perspectives of the parties involved. Using a game theoretic approach together with mathematical modelling, results are presented in an integrated manner with key topics that require further research highlighted in order to serve as a starting point for researchers (engineers and statisticians) who are interested in doing further work in these areas. Designed to assist practitioners (managers, engineers, applied statisticians) who are involved with extended warranties, maintenance service contracts and lease contracts, the book provides them with the models and techniques needed for proper cost analysis and effective decision-making. The book is also suitable for use as a reference text in industrial engineering, applied statistics, operations research and management.

  17. Material Selection for Cable Gland to Improved Reliability of the High-hazard Industries

    Science.gov (United States)

    Vashchuk, S. P.; Slobodyan, S. M.; Deeva, V. S.; Vashchuk, D. S.

    2018-01-01

    The sealed cable glands (SCG) are available to ensure safest connection sheathed single wire for the hazard production facility (nuclear power plant and others) the same as pilot cable, control cables, radio-frequency cables et al. In this paper, we investigate the specifics of the material selection of SCG with the express aim of hazardous man-made facility. We discuss the safe working conditions for cable glands. The research indicates the sintering powdered metals cables provide the reliability growth due to their properties. A number of studies have demonstrated the verification of material selection. On the face of it, we make findings indicating that double glazed sealed units could enhance reliability. We had evaluated sample reliability under fire conditions, seismic load, and pressure containment failure. We used the samples mineral insulated thermocouple cable.

  18. Money-back guarantee warranty policy with preventive maintenance strategy for sensor-embedded remanufactured products

    Science.gov (United States)

    Alqahtani, Ammar Y.; Gupta, Surendra M.

    2018-01-01

    In today's global environment, technology is constantly evolving. Being able to stay up-to-date with the very latest technological advances can be extremely hard to accomplish. As a result of these changes and developments in technology, which often come unexpectedly, consumers are frequently tempted to update their devices to the very latest model. The result is that the life cycle of a product is becoming shorter and shorter than before. Manufacturers attempt to respond to consumers' concerns involving environmental issues as well as the more governmentally stringent environmental legislations by establishing facilities which include the minimization of the totality of waste relocated to landfills by recovering materials and components from returned, or End-Of-Life products and reuse them to build a remanufactured product, and/or novel components. With the rapid growth of interest in remanufactured products' market, offering warranty for remanufactured products and components is becoming a necessity for remanufacturer in order to meet customers' requirement and as a marketing mechanism. During that process, maintenance policies are of great importance in order to reduce the warranty cost on the remanufacturer. In this paper, an optimization simulation model for remanufactured items sold with one-dimensional non-renewing money-back guarantee (MBG) warranty policy is proposed from the view of remanufacturer, in which, an End-Of-Life product is subjected to upgrade action at the end of its past life and during the warranty period, preventive maintenance actions are carried out when the remaining life of the product reaches a pre-specified value so that the remanufacturer's expected profit can be maximized. Finally, a numerical example and design of experiment analysis are provided to demonstrate the proposed approach.

  19. A rule induction approach to improve Monte Carlo system reliability assessment

    International Nuclear Information System (INIS)

    Rocco S, Claudio M.

    2003-01-01

    A Decision Tree (DT) approach to build empirical models for use in Monte Carlo reliability evaluation is presented. The main idea is to develop an estimation algorithm, by training a model on a restricted data set, and replacing the Evaluation Function (EF) by a simpler calculation, which provides reasonably accurate model outputs. The proposed approach is illustrated with two systems of different size, represented by their equivalent networks. The robustness of the DT approach as an approximated method to replace the EF is also analysed. Excellent system reliability results are obtained by training a DT with a small amount of information

  20. Introduction to quality and reliability engineering

    CERN Document Server

    Jiang, Renyan

    2015-01-01

    This book presents the state-of-the-art in quality and reliability engineering from a product life cycle standpoint. Topics in reliability include reliability models, life data analysis and modeling, design for reliability and accelerated life testing, while topics in quality include design for quality, acceptance sampling and supplier selection, statistical process control, production tests such as screening and burn-in, warranty and maintenance. The book provides comprehensive insights into two closely related subjects, and includes a wealth of examples and problems to enhance reader comprehension and link theory and practice. All numerical examples can be easily solved using Microsoft Excel. The book is intended for senior undergraduate and post-graduate students in related engineering and management programs such as mechanical engineering, manufacturing engineering, industrial engineering and engineering management programs, as well as for researchers and engineers in the quality and reliability fields. D...

  1. Scoring haemophilic arthropathy on X-rays: improving inter- and intra-observer reliability and agreement using a consensus atlas

    Energy Technology Data Exchange (ETDEWEB)

    Foppen, Wouter; Schaaf, Irene C. van der; Beek, Frederik J.A. [University Medical Center Utrecht, Department of Radiology (Netherlands); Verkooijen, Helena M. [University Medical Center Utrecht, Department of Radiology (Netherlands); University Medical Center Utrecht, Julius Center for Health Sciences and Primary Care, Utrecht (Netherlands); Fischer, Kathelijn [University Medical Center Utrecht, Julius Center for Health Sciences and Primary Care, Utrecht (Netherlands); University Medical Center Utrecht, Van Creveldkliniek, Department of Hematology, Utrecht (Netherlands)

    2016-06-15

    The radiological Pettersson score (PS) is widely applied for classification of arthropathy to evaluate costly haemophilia treatment. This study aims to assess and improve inter- and intra-observer reliability and agreement of the PS. Two series of X-rays (bilateral elbows, knees, and ankles) of 10 haemophilia patients (120 joints) with haemophilic arthropathy were scored by three observers according to the PS (maximum score 13/joint). Subsequently, (dis-)agreement in scoring was discussed until consensus. Example images were collected in an atlas. Thereafter, second series of 120 joints were scored using the atlas. One observer rescored the second series after three months. Reliability was assessed by intraclass correlation coefficients (ICC), agreement by limits of agreement (LoA). Median Pettersson score at joint level (PS{sub joint}) of affected joints was 6 (interquartile range 3-9). Using the consensus atlas, inter-observer reliability of the PS{sub joint} improved significantly from 0.94 (95 % confidence interval (CI) 0.91-0.96) to 0.97 (CI 0.96-0.98). LoA improved from ±1.7 to ±1.1 for the PS{sub joint}. Therefore, true differences in arthropathy were differences in the PS{sub joint} of >2 points. Intra-observer reliability of the PS{sub joint} was 0.98 (CI 0.97-0.98), intra-observer LoA were ±0.9 points. Reliability and agreement of the PS improved by using a consensus atlas. (orig.)

  2. Pricing and inventory policies for Hi-tech products under replacement warranty

    Science.gov (United States)

    Tsao, Yu-Chung; Teng, Wei-Guang; Chen, Ruey-Shii; Chou, Wang-Ying

    2014-06-01

    Companies, especially in the Hi-tech (high-technology) industry (such as computer, communication and consumer electronic products), often provide a replacement warranty period for purchased items. In reality, simultaneously determining the price and inventory decisions under warranty policy is an important issue. The objective of this paper is to develop a joint pricing and inventory model for Hi-tech products under replacement warranty policy. In the first model, we consider a Hi-tech product feature in which the selling price is declining in a trend. We determine the optimal inventory level for each period and retail price for the first period while maximising the total profit. In the second model, we further determine the optimal retail price and inventory level for each period in the dynamic demand market. This study develops solution approaches to solve the problems described above. Numerical analysis discusses the influence of system parameters on the company's decisions and behaviours. The results of this study could serve as a reference for business managers or administrators.

  3. The impact of intrinsic motivation on session attendance and reliable cognitive improvement in cognitive remediation in schizophrenia.

    Science.gov (United States)

    Bryce, S D; Lee, S J; Ponsford, J L; Lawrence, R J; Tan, E J; Rossell, S L

    2018-06-20

    Cognitive remediation (CR) is considered a potentially effective method of improving cognitive function in people with schizophrenia. Few studies, however, have explored the role of intrinsic motivation on treatment utilization or training outcomes in CR in this population. This study explored the impact of task-specific intrinsic motivation on attendance and reliable cognitive improvement in a controlled trial comparing CR with a computer game (CG) playing control. Forty-nine participants with schizophrenia or schizoaffective disorder, allocated to 10 weeks of group-based CR (n = 25) or CG control (n = 24), provided complete outcome data at baseline. Forty-three participants completed their assigned intervention. Cognition, psychopathology and intrinsic motivation were measured at baseline and end-treatment. Regression analyses explored the relative contribution of baseline motivation and other clinical factors to session attendance as well as the association of baseline and change in intrinsic motivation with the odds of reliable cognitive improvement (calculated using reliable change indices). Baseline reports of perceived program value were the only significant multivariable predictor of session attendance when including global cognition and psychiatric symptomatology. The odds of reliable cognitive improvement significantly increased with greater improvements in program interest and value from baseline to end-treatment. Motivational changes over time were highly variable between participants. Task-specific intrinsic motivation in schizophrenia may represent an important patient-related factor that contributes to session attendance and cognitive improvements in CR. Regular evaluation and enhancement of intrinsic motivation in cognitively enhancing interventions may optimize treatment engagement and the likelihood of meaningful training outcomes. Copyright © 2018 Elsevier B.V. All rights reserved.

  4. Item Analysis to Improve Reliability for an Internal Medicine Undergraduate OSCE

    Science.gov (United States)

    Auewarakul, Chirayu; Downing, Steven M.; Praditsuwan, Rungnirand; Jaturatamrong, Uapong

    2005-01-01

    Utilization of objective structured clinical examinations (OSCEs) for final assessment of medical students in Internal Medicine requires a representative sample of OSCE stations. The reliability and generalizability of OSCE scores provides validity evidence for OSCE scores and supports its contribution to the final clinical grade of medical…

  5. The National Surgical Quality Improvement Program 30-Day Challenge: Microsurgical Breast Reconstruction Outcomes Reporting Reliability

    Directory of Open Access Journals (Sweden)

    Austin D. Chen

    2018-03-01

    Conclusion:. For immediate, free-tissue breast reconstruction, the ACS-NSQIP may be reliable for monitoring and comparing SSI, WD, URO, and URA rates. However, clinicians may find it useful to understand limitations of the ACS-NSQIP for complications and risk factors, as it may underreport complications occurring beyond 30 days.

  6. Inducement of Design Parameters for Reliability Improvement of Servo Actuator for Hydraulic Valve Operation

    Energy Technology Data Exchange (ETDEWEB)

    Sung, Baek Ju; Kim, Do Sik [Korea Institute of Machinery and Materials, Daejeon (Korea, Republic of)

    2014-05-15

    The precision hydraulic valve is widely used in various industrial field like aircraft, automobile, and general machinery. Servo actuator is the most important device for driving the precise hydraulic valve. The reliable operation of servo actuator effects on the overall hydraulic system. The performance of servo actuator relies on frequency response and step response according to arbitrary input signal. In this paper, we performed the analysis for the components of servo actuator to satisfy the reliable operation and response characteristics through the reliability analysis, and also induced the design parameters to realize the reliable operation and fast response characteristics of servo actuator for hydraulic valve operation through the empirical knowledge of experts and electromagnetic theories. We suggested the design equations to determine the values of design parameters of servo actuator as like bobbin size, length of yoke and plunger and turn number of coil, and verified the achieved design values through FEM analysis and performance tests using some prototypes of servo actuators adapted in hydraulic valve.

  7. Indirect thermal control for improved reliability of Modular Multilevel Converter by utilizing circulating current

    DEFF Research Database (Denmark)

    Dowlatabadi, Mohammadkazem Bakhshizadeh; Ma, Ke; Loh, Poh Chiang

    2015-01-01

    semiconductor devices are comprehensively investigated. Also a novel control strategy by utilizing the circulating current is proposed to enhance the reliability performance of MMC in order to limit the amplitude of thermal cycles. It is concluded that the circulating current may change the losses and thermal...

  8. Improving Phrap-based assembly of the rat using "reliable" overlaps.

    Directory of Open Access Journals (Sweden)

    Michael Roberts

    2008-03-01

    Full Text Available The assembly methods used for whole-genome shotgun (WGS data have a major impact on the quality of resulting draft genomes. We present a novel algorithm to generate a set of "reliable" overlaps based on identifying repeat k-mers. To demonstrate the benefits of using reliable overlaps, we have created a version of the Phrap assembly program that uses only overlaps from a specific list. We call this version PhrapUMD. Integrating PhrapUMD and our "reliable-overlap" algorithm with the Baylor College of Medicine assembler, Atlas, we assemble the BACs from the Rattus norvegicus genome project. Starting with the same data as the Nov. 2002 Atlas assembly, we compare our results and the Atlas assembly to the 4.3 Mb of rat sequence in the 21 BACs that have been finished. Our version of the draft assembly of the 21 BACs increases the coverage of finished sequence from 93.4% to 96.3%, while simultaneously reducing the base error rate from 4.5 to 1.1 errors per 10,000 bases. There are a number of ways of assessing the relative merits of assemblies when the finished sequence is available. If one views the overall quality of an assembly as proportional to the inverse of the product of the error rate and sequence missed, then the assembly presented here is seven times better. The UMD Overlapper with options for reliable overlaps is available from the authors at http://www.genome.umd.edu. We also provide the changes to the Phrap source code enabling it to use only the reliable overlaps.

  9. The reliability improvement plan of hot cell examination data by introducing of Kolas

    International Nuclear Information System (INIS)

    Hong, Kwon Pyo; Park, Dae Gyu; Ahn, Sang Bok; Choo, Yong Sun; Song, Wung Sup; Jung, Yang Hong; Yoo, Byung Ok; Baik, Seung Je; Lim, Nam Jin; Nam Ju Hee

    2000-01-01

    For enhancement of hot cell data reliability produced at Irradiated Material Examination Facility in KAERI,Korea a project to introduce Kolas of National Quality Assurance Institute. By Kolas introduction the examination data currently produced would be reinforced by additional function of uncertainty evaluation and would obtained more reliable data. The all of data collected would be quality controlled, so that it would be re-traceable. Presently at IMEF shock test, tension test, dimension measurement test, hardness test, density test, and composition analysis test will be subject to Kolas. It is also planned to expand the number of test items in near future. At the end of 2000 year IMEF aims to secure the certificate issued by the National Quality Assurance Institute. (Hong, J. S.)

  10. Improvement of the reliability and efficiency of the NPP operation by training high-skilled personnel

    International Nuclear Information System (INIS)

    Korolev, V.V.; Sereda, G.A.

    1981-01-01

    Nuclear power at the modern stage of development is characterized by utilization of large power commercial reactors high technical specifications and economic parameters of which can be provided only at high reliability of the equipment and high qualification of the personnel. Special educational institution - Institute of nuclear engineering is organized for education of the operation personnel of high qualification for modern NPPs. Discussed are some problems occurring in this connection [ru

  11. A Framework to Improve Communication and Reliability Between Cloud Consumer and Provider in the Cloud

    OpenAIRE

    Vivek Sridhar

    2014-01-01

    Cloud services consumers demand reliable methods for choosing appropriate cloud service provider for their requirements. Number of cloud consumer is increasing day by day and so cloud providers, hence requirement for a common platform for interacting between cloud provider and cloud consumer is also on the raise. This paper introduces Cloud Providers Market Platform Dashboard. This will act as not only just cloud provider discoverability but also provide timely report to consumer on cloud ser...

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

    OpenAIRE

    Cioclov, Dimitru Dragos

    2013-01-01

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

  13. The improvement of the connections reliability in a local communication system

    International Nuclear Information System (INIS)

    Buisson, J.; Sanchis, P.

    1986-01-01

    The local communication systems used in the management of the industrial processes must fulfil more severe conditions concerning the reliability and safety than those used in bureaucratics. After mentioning the specific requirements the solutions for the realization of a local industrial communication system are presented. Studies to develop an optical fibers coupling system for a linear network used for the transmission in a hostile medium are mentioned

  14. Optimized work control process to improve safety and reliability in a risk-based and deregulated environment

    International Nuclear Information System (INIS)

    Anderson, Jon G.; Jeffries, Jeffrey D. E.; Mairs, Todd P.; Rahn, Frank J.

    1999-01-01

    This paper provides an overview of strategic models to assist power generating plants to improve their work control processes. These models include mechanisms to continually keep the process up to date. Included in the work control process are elements for system cost/performance analysis, life-cycle maintenance planning, on-line scheduling and look-ahead techniques, and schedule implementation to conduct work on the asset. The paper also discusses how risk management associated with work control issues that effect the safety and reliability, as well as O and M costs, is integrated into this strategy. The work control process is a pervasive and critical element in the successful implementation of operations and work management programs. While providing a method to implement maintenance activities in a cost-effective manner, the work control process improves plant safety and system reliability

  15. Time-dependent Reliability of Dynamic Systems using Subset Simulation with Splitting over a Series of Correlated Time Intervals

    Science.gov (United States)

    2013-08-01

    cost due to potential warranty costs, repairs and loss of market share. Reliability is the probability that the system will perform its intended...MCMC and splitting sampling schemes. Our proposed SS/ STP method is presented in Section 4, including accuracy bounds and computational effort

  16. 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...

  17. Comparison of different reliability improving investment strategies of Finnish medium-voltage distribution systems

    Energy Technology Data Exchange (ETDEWEB)

    Laagland, H.

    2012-07-01

    The electricity distribution sector in Finland is highly regulated and the return on investments in distribution networks is low. Low profits don't make the electricity distribution sector attractive to outside investors. During the second regulatory period of 2008-2011 incentives are included into the Finnish regulation model which allows higher profits for the network owners for right allocated network investments leading to lower operation and interruption costs. The goal of the thesis is to find cost-effective medium-voltage distribution system investment strategies for the Finnish power distribution companies with respect to the incentives of the second regulatory period. In this work the sectionalisation concept is further developed by deriving equations for a homogeneous electricity distribution system for the economical and reliability indices as a function of the number of sectionalisation zones. The cost-effective medium-voltage distribution system investment strategies are found by studying the technical and economic interaction of feeder automation on different network structures. Ten feeder automation schemes have been applied to six urban/rural area generic feeders and two real rural area feeders of a distribution company in western Finland. The analytical approach includes modelling of the feeders and feeder functions and calculation of the economical and reliability indices. The following investment areas are included: different electricity distribution systems, new substation, new switching station, central earth-fault current compensation, cabling and feeder automation. The value of the results of this work is that they reveal the influence that feeder automation has on the reliability and economy of different distribution structures. This created transparency enables a national and/or distribution company network investment strategy to optimise the economic benefits of investments. (orig.)

  18. Beyond redundancy how geographic redundancy can improve service availability and reliability of computer-based systems

    CERN Document Server

    Bauer, Eric; Eustace, Dan

    2012-01-01

    "While geographic redundancy can obviously be a huge benefit for disaster recovery, it is far less obvious what benefit is feasible and likely for more typical non-catastrophic hardware, software, and human failures. Georedundancy and Service Availability provides both a theoretical and practical treatment of the feasible and likely benefits of geographic redundancy for both service availability and service reliability. The text provides network/system planners, IS/IT operations folks, system architects, system engineers, developers, testers, and other industry practitioners with a general discussion about the capital expense/operating expense tradeoff that frames system redundancy and georedundancy"--

  19. Improving Reliability of a fire-fighting pump set with Axiomatic Design

    Directory of Open Access Journals (Sweden)

    Arcidiacono Gabriele

    2017-01-01

    Full Text Available This paper introduces a case study featuring Axiomatic Design and Multi-Level Hierarchical model (MLH applied to redesign a fire-fighting pump set. In particular, two different design concepts are presented to be applied to the supporting frame of the system to limit a vibration problem that can arise during potential malfunctioning of the fire-fighting pump. The selection of the best design has been carried out through reliability evaluation process and through the cost of failure based on the MLH model.

  20. Reliability and Maintainability Model (RAM): User and Maintenance Manual. Part 2; Improved Supportability Analysis

    Science.gov (United States)

    Ebeling, Charles E.

    1996-01-01

    This report documents the procedures for utilizing and maintaining the Reliability & Maintainability Model (RAM) developed by the University of Dayton for the National Aeronautics and Space Administration (NASA) Langley Research Center (LaRC). The purpose of the grant is to provide support to NASA in establishing operational and support parameters and costs of proposed space systems. As part of this research objective, the model described here was developed. This Manual updates and supersedes the 1995 RAM User and Maintenance Manual. Changes and enhancements from the 1995 version of the model are primarily a result of the addition of more recent aircraft and shuttle R&M data.

  1. A dissociation between engagement and learning: Enthusiastic instructions fail to reliably improve performance on a memory task.

    Directory of Open Access Journals (Sweden)

    Benjamin A Motz

    Full Text Available Despite widespread assertions that enthusiasm is an important quality of effective teaching, empirical research on the effect of enthusiasm on learning and memory is mixed and largely inconclusive. To help resolve these inconsistencies, we conducted a carefully-controlled laboratory experiment, investigating whether enthusiastic instructions for a memory task would improve recall accuracy. Scripted videos, either enthusiastic or neutral, were used to manipulate the delivery of task instructions. We also manipulated the sequence of learning items, replicating the spacing effect, a known cognitive technique for memory improvement. Although spaced study reliably improved test performance, we found no reliable effect of enthusiasm on memory performance across two experiments. We did, however, find that enthusiastic instructions caused participants to respond to more item prompts, leaving fewer test questions blank, an outcome typically associated with increased task motivation. We find no support for the popular claim that enthusiastic instruction will improve learning, although it may still improve engagement. This dissociation between motivation and learning is discussed, as well as its implications for education and future research on student learning.

  2. A dissociation between engagement and learning: Enthusiastic instructions fail to reliably improve performance on a memory task.

    Science.gov (United States)

    Motz, Benjamin A; de Leeuw, Joshua R; Carvalho, Paulo F; Liang, Kaley L; Goldstone, Robert L

    2017-01-01

    Despite widespread assertions that enthusiasm is an important quality of effective teaching, empirical research on the effect of enthusiasm on learning and memory is mixed and largely inconclusive. To help resolve these inconsistencies, we conducted a carefully-controlled laboratory experiment, investigating whether enthusiastic instructions for a memory task would improve recall accuracy. Scripted videos, either enthusiastic or neutral, were used to manipulate the delivery of task instructions. We also manipulated the sequence of learning items, replicating the spacing effect, a known cognitive technique for memory improvement. Although spaced study reliably improved test performance, we found no reliable effect of enthusiasm on memory performance across two experiments. We did, however, find that enthusiastic instructions caused participants to respond to more item prompts, leaving fewer test questions blank, an outcome typically associated with increased task motivation. We find no support for the popular claim that enthusiastic instruction will improve learning, although it may still improve engagement. This dissociation between motivation and learning is discussed, as well as its implications for education and future research on student learning.

  3. Follow-up of CT-derived airway wall thickness: Correcting for changes in inspiration level improves reliability

    Energy Technology Data Exchange (ETDEWEB)

    Pompe, Esther, E-mail: e.pompe@umcutrecht.nl [Department of Respiratory Medicine, University Medical Center Utrecht, Utrecht (Netherlands); Rikxoort, Eva M. van [Department of Radiology, Radboud University Medical Center, Nijmegen (Netherlands); Mets, Onno M. [Department of Radiology, University Medical Center Utrecht, Utrecht (Netherlands); Charbonnier, Jean-Paul [Department of Radiology, Radboud University Medical Center, Nijmegen (Netherlands); Kuhnigk, Jan-Martin [Institute for Medical Image Computing, Fraunhofer MEVIS, Bremen (Germany); Koning, Harry J. de [Department of Public Health, Erasmus Medical Center, Rotterdam (Netherlands); Oudkerk, Matthijs [University of Groningen, University Medical Center Groningen, Groningen, Department of Radiology (Netherlands); Vliegenthart, Rozemarijn [University of Groningen, University Medical Center Groningen, Groningen, Department of Radiology (Netherlands); University of Groningen, University Medical Center Groningen, Center for Medical Imaging-North East Netherlands, Groningen (Netherlands); Zanen, Pieter; Lammers, Jan-Willem J. [Department of Respiratory Medicine, University Medical Center Utrecht, Utrecht (Netherlands); Ginneken, Bram van [Department of Radiology, Radboud University Medical Center, Nijmegen (Netherlands); Jong, Pim A. de; Mohamed Hoesein, Firdaus A.A. [Department of Radiology, University Medical Center Utrecht, Utrecht (Netherlands)

    2016-11-15

    Objectives: Airway wall thickness (AWT) is affected by changes in lung volume. This study evaluated whether correcting AWT on computed tomography (CT) for differences in inspiration level improves measurement agreement, reliability, and power to detect changes over time. Methods: Participants of the Dutch-Belgian lung cancer screening trial who underwent 3-month repeat CT for an indeterminate pulmonary nodule were included. AWT on CT was calculated by the square root of the wall area at a theoretical airway with an internal perimeter of 10 mm (Pi10). The scan with the highest lung volume was labelled as the reference scan and the scan with the lowest lung volume was labelled as the comparison scan. Pi10 derived from the comparison scan was corrected by multiplying it with the ratio of CT lung volume of the comparison scan to CT lung volume on the reference scan. Agreement of uncorrected and corrected Pi10 was studied with the Bland-Altman method, reliability with intra-class correlation coefficients (ICC), and power to detect changes over time was calculated. Results: 315 male participants were included. Limit of agreement and reliability for Pi10 was −0.61 to 0.57 mm (ICC = 0.87), which improved to −0.38 to 0.37 mm (ICC = 0.94) after correction for inspiration level. To detect a 15% change over 3 months, 71 subjects are needed for Pi10 and 26 subjects for Pi10 adjusted for inspiration level. Conclusions: Correcting Pi10 for differences in inspiration level improves reliability, agreement, and power to detect changes over time.

  4. Linking Quality Assurance to Performance Improvement to Produce a High Reliability Organization

    International Nuclear Information System (INIS)

    Silvey, Andrea B.; Warrick, Louise H.

    2008-01-01

    Three basic change management models are currently used in healthcare to produce and sustain quality improvement. We have presented the context to determine where any particular organization stands within these paradigms. We also have introduced a change-management tool used to assess, plan, and monitor leadership effort and commitment to quality improvement and culture change activities, tracked as 'momentum for change.' This 'momentum' is measured at eight discrete levels, from recognizing a performance gap to officially implementing changes intended to improve quality

  5. Improving reliability of state estimation programming and computing suite based on analyzing a fault tree

    Directory of Open Access Journals (Sweden)

    Kolosok Irina

    2017-01-01

    Full Text Available Reliable information on the current state parameters obtained as a result of processing the measurements from systems of the SCADA and WAMS data acquisition and processing through methods of state estimation (SE is a condition that enables to successfully manage an energy power system (EPS. SCADA and WAMS systems themselves, as any technical systems, are subject to failures and faults that lead to distortion and loss of information. The SE procedure enables to find erroneous measurements, therefore, it is a barrier for the distorted information to penetrate into control problems. At the same time, the programming and computing suite (PCS implementing the SE functions may itself provide a wrong decision due to imperfection of the software algorithms and errors. In this study, we propose to use a fault tree to analyze consequences of failures and faults in SCADA and WAMS and in the very SE procedure. Based on the analysis of the obtained measurement information and on the SE results, we determine the state estimation PCS fault tolerance level featuring its reliability.

  6. The reliability of in-training assessment when performance improvement is taken into account

    NARCIS (Netherlands)

    van Lohuizen, M.T.; Kuks, J.B.; van Hell, E.A.; Raat, A.N.; Stewart, R.E.; Cohen-Schotanus, J.

    2010-01-01

    During in-training assessment students are frequently assessed over a longer period of time and therefore it can be expected that their performance will improve. We studied whether there really is a measurable performance improvement when students are assessed over an extended period of time and how

  7. Improving Marking Reliability of Scientific Writing with the Developing Understanding of Assessment for Learning Programme

    Science.gov (United States)

    Bird, Fiona L.; Yucel, Robyn

    2013-01-01

    The Developing Understanding of Assessment for Learning (DUAL) programme was developed with the dual aims of improving both the quality and consistency of feedback students receive and the students' ability to use that feedback to improve. DUAL comprises a range of processes (including marking rubrics, sample reports, moderation discussions and…

  8. Water chemistry data acquisition, processing, evaluation and diagnostic systems in Light Water Reactors: Future improvement of plant reliability and safety

    International Nuclear Information System (INIS)

    Uchida, S.; Takiguchi, H.; Ishigure, K.

    2006-01-01

    Data acquisition, processing and evaluation systems have been applied in major Japanese PWRs and BWRs to provide (1) reliable and quick data acquisition with manpower savings in plant chemical laboratories and (2) smooth and reliable information transfer among chemists, plant operators, and supervisors. Data acquisition systems in plants consist of automatic and semi-automatic instruments for chemical analyses, e. g., X-ray fluorescence analysis and ion chromatography, while data processing systems consist of PC base-sub-systems, e.g., data storage, reliability evaluation, clear display, and document preparation for understanding the plant own water chemistry trends. Precise and reliable evaluations of water chemistry data are required in order to improve plant reliability and safety. For this, quality assurance of the water chemistry data acquisition system is needed. At the same time, theoretical models are being applied to bridge the gaps between measured water chemistry data and the information desired to understand the interaction of materials and cooling water in plants. Major models which have already been applied for plant evaluation are: (1) water radiolysis models for BWRs and PWRs; (2) crevice radiolysis model for SCC in BWRs; and (3) crevice pH model for SG tubing in PWRs. High temperature water chemistry sensors and automatic plant diagnostic systems have been applied in only restricted areas. ECP sensors are gaining popularity as tools to determine the effects of hydrogen injection in BWR systems. Automatic plant diagnostic systems based on artificial intelligence will be more popular after having sufficient experience with off line diagnostic systems. (author)

  9. Improving Reliability of Service Operation Using FMEA Review and New Opportunity for Investigations

    Science.gov (United States)

    Sutrisno, Agung; Gunawan, Indra

    2016-01-01

    Despite its growing contribution to the global economy, investigation on the application status of service FMEA study to support realization of reliable service operation is very limited in literature. Motivated by such situation, the paper presented an initial survey on the status and research gaps in developing and applying FMEA in service sectors. Systematic preliminary survey using specific criteria are undertaken. Our study indicated that development and application of service FMEA are partially addressing the characteristics of service operations and it is still applied into the good deed and profit oriented operations. Opportunities for further investigation pertaining to advancement of its decision supporting tool for service risk appraisal, its modification to cope with sustainability related requirements and application of service FMEA in not for profit oriented operations are presented as new avenues for further investigation

  10. Improving Reliability of High Power Quasi-CW Laser Diode Arrays for Pumping Solid State Lasers

    Science.gov (United States)

    Amzajerdian, Farzin; Meadows, Byron L.; Baker, Nathaniel R.; Barnes, Bruce W.; Baggott, Renee S.; Lockard, George E.; Singh, Upendra N.; Kavaya, Michael J.

    2005-01-01

    Most Lidar applications rely on moderate to high power solid state lasers to generate the required transmitted pulses. However, the reliability of solid state lasers, which can operate autonomously over long periods, is constrained by their laser diode pump arrays. Thermal cycling of the active regions is considered the primary reason for rapid degradation of the quasi-CW high power laser diode arrays, and the excessive temperature rise is the leading suspect in premature failure. The thermal issues of laser diode arrays are even more drastic for 2-micron solid state lasers which require considerably longer pump pulses compared to the more commonly used pump arrays for 1-micron lasers. This paper describes several advanced packaging techniques being employed for more efficient heat removal from the active regions of the laser diode bars. Experimental results for several high power laser diode array devices will be reported and their performance when operated at long pulsewidths of about 1msec will be described.

  11. Using Model Replication to Improve the Reliability of Agent-Based Models

    Science.gov (United States)

    Zhong, Wei; Kim, Yushim

    The basic presupposition of model replication activities for a computational model such as an agent-based model (ABM) is that, as a robust and reliable tool, it must be replicable in other computing settings. This assumption has recently gained attention in the community of artificial society and simulation due to the challenges of model verification and validation. Illustrating the replication of an ABM representing fraudulent behavior in a public service delivery system originally developed in the Java-based MASON toolkit for NetLogo by a different author, this paper exemplifies how model replication exercises provide unique opportunities for model verification and validation process. At the same time, it helps accumulate best practices and patterns of model replication and contributes to the agenda of developing a standard methodological protocol for agent-based social simulation.

  12. Improving Wind Turbine Drivetrain Reliability Using a Combined Experimental, Computational, and Analytical Approach

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Y.; van Dam, J.; Bergua, R.; Jove, J.; Campbell, J.

    2015-03-01

    Nontorque loads induced by the wind turbine rotor overhang weight and aerodynamic forces can greatly affect drivetrain loads and responses. If not addressed properly, these loads can result in a decrease in gearbox component life. This work uses analytical modeling, computational modeling, and experimental data to evaluate a unique drivetrain design that minimizes the effects of nontorque loads on gearbox reliability: the Pure Torque(R) drivetrain developed by Alstom. The drivetrain has a hub-support configuration that transmits nontorque loads directly into the tower rather than through the gearbox as in other design approaches. An analytical model of Alstom's Pure Torque drivetrain provides insight into the relationships among turbine component weights, aerodynamic forces, and the resulting drivetrain loads. Main shaft bending loads are orders of magnitude lower than the rated torque and are hardly affected by wind conditions and turbine operations.

  13. Operating experience and reliability improvements on the 5 kW CW klystron at Jefferson Lab

    International Nuclear Information System (INIS)

    Nelson, R.; Holben, S.

    1997-01-01

    With substantial operating hours on the RF system, considerable information on reliability of the 5 kW CW klystrons has been obtained. High early failure rates led to examination of the operating conditions and failure modes. Internal ceramic contamination caused premature failure of gun potting material and ultimate tube demise through arcing or ceramic fracture. A planned course of reporting and reconditioning of approximately 300 klystrons, plus careful attention to operating conditions and periodic analysis of operational data, has substantially reduced the failure rate. It is anticipated that implementation of planned supplemental monitoring systems for the klystrons will allow most catastrophic failures to be avoided. By predicting end of life, tubes can be changed out before they fail, thus minimizing unplanned downtime. Initial tests have also been conducted on this same klystron operated at higher voltages with resultant higher output power. The outcome of these tests will provide information to be considered for future upgrades to the accelerator

  14. A new method for improving the reliability of fracture toughness surveillance of nuclear pressure vessel by neutron irradiated embrittlement

    International Nuclear Information System (INIS)

    Zhang Xinping; Shi Yaowu

    1992-01-01

    In order to obtain more information from neutron irradiated sample specimens and raise the reliability of fracture toughness surveillance test, it has more important significance to repeatedly exploit the broken Charpy-size specimen which had been tested in surveillance test. In this work, on the renewing design and utilization for Charpy-size specimens, 9 data of fracture toughness can be gained from one pre-cracked side-grooved Charpy-size specimen while at the preset usually only 1 to 3 data of fracture toughness can be obtained from one Chharpy-size specimen. Thus, it is found that the new method would obviously improve the reliability of fracture toughness surveillance test and evaluation. Some factors which affect the reasonable design of pre-cracked deep side-groove Charpy-size compound specimen have been discussed

  15. Reliability improvement of PMZNT relaxor ferroelectrics through surface modification by MnO2 doping against electroplating-induced degradation

    International Nuclear Information System (INIS)

    Cao Jiangli; Li Longtu; Gui Zhilun

    2003-01-01

    Electroplating treatment, scanning electron microscopy (SEM) observation, X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) analyses were conducted to investigate the reliability improvement of lead magnesium niobate-based ceramics (PMZNT) through MnO 2 vaporous doping against hydrogen reduction during electroplating. The results showed that manganese dopant was reduced to be +3 oxidation state during the sintering and Mn 3+ was incorporated into the perovskite lattice; however, only the outermost ceramics surface was doped while 50 μm beneath kept unchanged. This technique proved to enhance the reliability of PMZNT against electroplating significantly without changing the dielectric properties of ceramics body. Based on the above results, the modification mechanism of MnO 2 vaporous doping was analyzed from the viewpoint of defect chemistry

  16. Improving accuracy of overhanging structures for selective laser melting through reliability characterization of single track formation on thick powder beds

    DEFF Research Database (Denmark)

    Mohanty, Sankhya; Hattel, Jesper Henri

    2016-01-01

    Repeatability and reproducibility of parts produced by selective laser melting is a standing issue, and coupled with a lack of standardized quality control presents a major hindrance towards maturing of selective laser melting as an industrial scale process. Consequently, numerical process...... modelling has been adopted towards improving the predictability of the outputs from the selective laser melting process. Establishing the reliability of the process, however, is still a challenge, especially in components having overhanging structures.In this paper, a systematic approach towards...... establishing reliability of overhanging structure production by selective laser melting has been adopted. A calibrated, fast, multiscale thermal model is used to simulate the single track formation on a thick powder bed. Single tracks are manufactured on a thick powder bed using same processing parameters...

  17. Improvement of mechanical reliability by patterned silver/Indium-Tin-Oxide structure for flexible electronic devices

    International Nuclear Information System (INIS)

    Baek, Kyunghyun; Jang, Kyungsoo; Lee, Youn-Jung; Ryu, Kyungyul; Choi, Woojin; Kim, Doyoung; Yi, Junsin

    2013-01-01

    We report the effect of silver (Ag)-buffer layer Indium-Tin-Oxide (ITO) film on a polyethylene terephthalate substrate on the electrical, optical and reliable properties for transparent–flexible displays. The electrical and optical characteristics of an ITO-only film and an Ag-layer-inserted ITO film are measured and compared to assess the applicability of the triple layered structure in flexible displays. The sheet resistance, the resistivity and the light transmittance of the ITO-only film were 400 Ω/sq, 1.33 × 10 −3 Ω-cm and 99.2%, while those of the ITO film inserted with a 10 nm thick Ag layer were 165 Ω/sq, 4.78 × 10 −4 Ω-cm and about 97%, respectively. To evaluate the mechanical reliability of the different ITO films, bending tests were carried out. After the dynamic bending test of 900 cycles, the sheet resistance of the ITO film inserted with the Ag layer changed from 154 Ω/sq to 475 Ω/sq, about a 3-time increase but that of the ITO-only film changed from 400 Ω/sq to 61,986 Ω/sq, about 150-time increase. When the radius is changed from 25 mm to 20 mm in the static bending test, the sheet resistance of the ITO-only film changed from 400 to 678.3 linearly whereas that of the Ag-layer inserted ITO film changed a little from 154.4 to 154.9. These results show that Ag-layer inserted ITO film had better mechanical characteristics than the ITO-only film. - Highlights: ► Transparent flexible electrode fabricated on glass substrate. ► Electrode fabricated using vertically-patterned design on glass substrate. ► Optimization of the vertical patterns ► Application of the vertically-patterned electrode in transparent–flexible electronics

  18. Improving preimplantation genetic diagnosis (PGD) reliability by selection of sperm donor with the most informative haplotype.

    Science.gov (United States)

    Malcov, Mira; Gold, Veronica; Peleg, Sagit; Frumkin, Tsvia; Azem, Foad; Amit, Ami; Ben-Yosef, Dalit; Yaron, Yuval; Reches, Adi; Barda, Shimi; Kleiman, Sandra E; Yogev, Leah; Hauser, Ron

    2017-04-26

    The study is aimed to describe a novel strategy that increases the accuracy and reliability of PGD in patients using sperm donation by pre-selecting the donor whose haplotype does not overlap the carrier's one. A panel of 4-9 informative polymorphic markers, flanking the mutation in carriers of autosomal dominant/X-linked disorders, was tested in DNA of sperm donors before PGD. Whenever the lengths of donors' repeats overlapped those of the women, additional donors' DNA samples were analyzed. The donor that demonstrated the minimal overlapping with the patient was selected for IVF. In 8 out of 17 carriers the markers of the initially chosen donors overlapped the patients' alleles and 2-8 additional sperm donors for each patient were haplotyped. The selection of additional sperm donors increased the number of informative markers and reduced misdiagnosis risk from 6.00% ± 7.48 to 0.48% ±0.68. The PGD results were confirmed and no misdiagnosis was detected. Our study demonstrates that pre-selecting a sperm donor whose haplotype has minimal overlapping with the female's haplotype, is critical for reducing the misdiagnosis risk and ensuring a reliable PGD. This strategy may contribute to prevent the transmission of affected IVF-PGD embryos using a simple and economical procedure. All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. DNA testing of donors was approved by the institutional Helsinki committee (registration number 319-08TLV, 2008). The present study was approved by the institutional Helsinki committee (registration number 0385-13TLV, 2013).

  19. Photovoltaic Reliability Group activities in USA and Brazil (Presentation Recording)

    Science.gov (United States)

    Dhere, Neelkanth G.; Cruz, Leila R. O.

    2015-09-01

    Recently prices of photovoltaic (PV) systems have been reduced considerably and may continue to be reduced making them attractive. If these systems provide electricity over the stipulated warranty period, it would be possible attain socket parity within the next few years. Current photovoltaic module qualifications tests help in minimizing infant mortality but do not guarantee useful lifetime over the warranty period. The PV Module Quality Assurance Task Force (PVQAT) is trying to formulate accelerated tests that will be useful towards achieving the ultimate goal of assuring useful lifetime over the warranty period as well as to assure manufacturing quality. Unfortunately, assuring the manufacturing quality may require 24/7 presence. Alternatively, collecting data on the performance of fielded systems would assist in assuring manufacturing quality. Here PV systems installed by home-owners and small businesses can constitute as an important untapped source of data. The volunteer group, PV - Reliable, Safe and Sustainable Quality! (PVRessQ!) is providing valuable service to small PV system owners. Photovoltaic Reliability Group (PVRG) is initiating activities in USA and Brazil to assist home owners and small businesses in monitoring photovoltaic (PV) module performance and enforcing warranty. It will work in collaboration with small PV system owners, consumer protection agencies. Brazil is endowed with excellent solar irradiance making it attractive for installation of PV systems. Participating owners of small PV systems would instruct inverter manufacturers to copy the daily e-mails to PVRG and as necessary, will authorize the PVRG to carry out review of PV systems. The presentation will consist of overall activities of PVRG in USA and Brazil.

  20. Low cost corrosion and oxidation resistant coatings for improved system reliability, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — In order to improve high-temperature oxidation and corrosion resistance of critical superalloy components in turbine engines innovative processing methods must be...

  1. Nuclear power plant safety and reliability improvements derived from operational experience analysis

    International Nuclear Information System (INIS)

    Zebroski, E.L.; Rosen, S.L.

    1983-01-01

    The frequency and distribution of significant events at operating nuclear power plants can be used as one of several indices to obtain a preliminary indication of unit and/or utility performance in the development and implementation of improvements aimed at reducing the probability or consequences of troublesome events. Initial data of this type are presented along with qualifications on the validity of such indicators. Planned further steps to improve this as a performance indicator are noted

  2. Improving Predictions with Reliable Extrapolation Schemes and Better Understanding of Factorization

    Science.gov (United States)

    More, Sushant N.

    New insights into the inter-nucleon interactions, developments in many-body technology, and the surge in computational capabilities has led to phenomenal progress in low-energy nuclear physics in the past few years. Nonetheless, many calculations still lack a robust uncertainty quantification which is essential for making reliable predictions. In this work we investigate two distinct sources of uncertainty and develop ways to account for them. Harmonic oscillator basis expansions are widely used in ab-initio nuclear structure calculations. Finite computational resources usually require that the basis be truncated before observables are fully converged, necessitating reliable extrapolation schemes. It has been demonstrated recently that errors introduced from basis truncation can be taken into account by focusing on the infrared and ultraviolet cutoffs induced by a truncated basis. We show that a finite oscillator basis effectively imposes a hard-wall boundary condition in coordinate space. We accurately determine the position of the hard-wall as a function of oscillator space parameters, derive infrared extrapolation formulas for the energy and other observables, and discuss the extension of this approach to higher angular momentum and to other localized bases. We exploit the duality of the harmonic oscillator to account for the errors introduced by a finite ultraviolet cutoff. Nucleon knockout reactions have been widely used to study and understand nuclear properties. Such an analysis implicitly assumes that the effects of the probe can be separated from the physics of the target nucleus. This factorization between nuclear structure and reaction components depends on the renormalization scale and scheme, and has not been well understood. But it is potentially critical for interpreting experiments and for extracting process-independent nuclear properties. We use a class of unitary transformations called the similarity renormalization group (SRG) transformations to

  3. Optimal Overhaul-Replacement Policies for Repairable Machine Sold with Warranty

    OpenAIRE

    Soemadi, Kusmaningrum; Iskandar, Bermawi P; Taroepratjeka, Harsono

    2014-01-01

    This research deals with an overhaul-replacement policy for a repairable machine sold with Free Replacement Warranty (FRW). The machine will be used for a finite horizon, T (T <), and evaluated at a fixed interval, s (s< T). At each evaluation point, the buyer considers three alternative decisions i.e. Keep the machine, Overhaul it, or Replace it with a new identical one. An overhaul can reduce the machine age virtually, but not to a point that the machine is as good as new. If the mac...

  4. Managing a two-echelon supply chain with price, warranty and quality dependent demand

    Directory of Open Access Journals (Sweden)

    Nikunja Mohan Modak

    2015-12-01

    Full Text Available This paper deals with a two-layer supply chain composed of one manufacturer and one retailer for single-type product. The demand function of the end customers depends on quality, warranty, and sales price of the product. The profit functions of the manufacturer and the retailers are maximized under centralized and decentralized approaches. Our study suggests that the joint profit in centralized system is always more than the decentralized system. Finally, the surplus profit in centralized system is shared according to their profits in decentralized system.

  5. Improving the Transmission System Reliability for the 154kV Radial Network Operation

    Energy Technology Data Exchange (ETDEWEB)

    Choo, Jin Boo; Yoo, Myeong Ho; Yoon, Young Beum; Kim, Tae Won [Korea Electric Power Research Institute, Taejon (Korea, Republic of); Lee, Gi Won; Chung, Beom Jin; Jung, Jung Won; Park, Kyu Hyun; Lee, Myung Hee; Kim, Hyun Jong; Kim, Chae Hee [KEYIN CO., (Korea, Republic of)

    1996-12-31

    Analyzing that 154kV radial network current ed operated, we developed Automatic Power Reconfiguration System(APRS) which restore blackout area. It consists of special data acquisition system(DAU) and central monitoring system for reason of protecting currently operating power system. In addition, it communicates using optical communication network for high speed data transmission and accuracy. An Accuracy of operation and stability of the developed system is tested using Real Time Digital Simulator in 3-bus equivalent model system. In An Outage case, our developed system can restore a blackout area in three second. An ability of the restoration of a blackout was verified by simulations. For the field test, the developed system was set up at SINCHON S/S, SESOMUN S/S, SINDANG S/S and MAJANG S/S governed by Seoul Power Transmission Center. If the system reliability is proved for a one year test in real power system, application of the system will be extended to the other substations.

  6. Reliability database of IEA-R1 Brazilian research reactor: Applications to the improvement of installation safety

    International Nuclear Information System (INIS)

    Oliveira, P.S.P.; Tondin, J.B.M.; Martins, M.O.; Yovanovich, M.; Ricci Filho, W.

    2010-01-01

    In this paper the main features of the reliability database being developed at Ipen-Cnen/SP for IEA-R1 reactor are briefly described. Besides that, the process for collection and updating of data regarding operation, failure and maintenance of IEA-R1 reactor components is presented. These activities have been conducted by the reactor personnel under the supervision of specialists in Probabilistic Safety Analysis (PSA). The compilation of data and subsequent calculation are based on the procedures defined during an IAEA Coordinated Research Project which Brazil took part in the period from 2001 to 2004. In addition to component reliability data, the database stores data on accident initiating events and human errors. Furthermore, this work discusses the experience acquired through the development of the reliability database covering aspects like improvements in the reactor records as well as the application of the results to the optimization of operation and maintenance procedures and to the PSA carried out for IEA-R1 reactor. (author)

  7. Get rid of it: To what extent might improved reliability reduce self-generation in Nigeria?

    International Nuclear Information System (INIS)

    Oseni, Musiliu O.

    2016-01-01

    Despite the global concerns surrounding the threats of climate change to both human health and sustainable environments, gasoline- or diesel-powered generators with non-negligible emissions have become a popular choice among Nigerian households due to the poor publicly provided electricity. This study examines the extent to which an improvement in publicly supplied electricity may reduce backup generation and, by implication, reduce emissions from Nigerian homes. The results from a random-effects probit analysis reveal that, although improved electricity service quality would significantly reduce self-generation, self-generation would continue in the country, especially among rich and educated households. The study concludes by highlighting the policy implications of the findings. - Highlights: •We study how improved electricity supply might reduce self-generation in Nigeria. •Households use their generators less than 40% of times they suffer outages. •Improved service quality would significantly reduce self-generation. •However, self-generation would continue among rich and educated households. •Import tariff and pollution tax can be used to further reduce self-generation.

  8. Improvement of Reliability of Diffusion Tensor Metrics in Thigh Skeletal Muscles.

    Science.gov (United States)

    Keller, Sarah; Chhabra, Avneesh; Ahmed, Shaheen; Kim, Anne C; Chia, Jonathan M; Yamamura, Jin; Wang, Zhiyue J

    2018-05-01

    Quantitative diffusion tensor imaging (DTI) of skeletal muscles is challenging due to the bias in DTI metrics, such as fractional anisotropy (FA) and mean diffusivity (MD), related to insufficient signal-to-noise ratio (SNR). This study compares the bias of DTI metrics in skeletal muscles via pixel-based and region-of-interest (ROI)-based analysis. DTI of the thigh muscles was conducted on a 3.0-T system in N = 11 volunteers using a fat-suppressed single-shot spin-echo echo planar imaging (SS SE-EPI) sequence with eight repetitions (number of signal averages (NSA) = 4 or 8 for each repeat). The SNR was calculated for different NSAs and estimated for the composite images combining all data (effective NSA = 48) as standard reference. The bias of MD and FA derived by pixel-based and ROI-based quantification were compared at different NSAs. An "intra-ROI diffusion direction dispersion angle (IRDDDA)" was calculated to assess the uniformity of diffusion within the ROI. Using our standard reference image with NSA = 48, the ROI-based and pixel-based measurements agreed for FA and MD. Larger disagreements were observed for the pixel-based quantification at NSA = 4. MD was less sensitive than FA to the noise level. The IRDDDA decreased with higher NSA. At NSA = 4, ROI-based FA showed a lower average bias (0.9% vs. 37.4%) and narrower 95% limits of agreement compared to the pixel-based method. The ROI-based estimation of FA is less prone to bias than the pixel-based estimations when SNR is low. The IRDDDA can be applied as a quantitative quality measure to assess reliability of ROI-based DTI metrics. Copyright © 2018 Elsevier B.V. All rights reserved.

  9. New design of engineered safety features-component control system to improve performance and reliability

    International Nuclear Information System (INIS)

    Kim, S.T.; Jung, H.W.; Lee, S.J.; Cho, C.H.; Kim, D.H.; Kim, H.

    2006-01-01

    Full text: Full text: The Engineered Safety Features-Component Control System (ESF-CCS) controls the engineered safety features of a Nuclear Power Plant such as Solenoid Operated Valves (SOV), Motor Operated Valves (MOV), pumps, dampers, etc. to mitigate the effects of a Design Basis Accident (DBA) or an abnormal operation. ESF-CCS serves as an interface system between the Plant Protection System (PPS) and remote actuation devices. ESF-CCS is composed of fault tolerant Group Controllers GC, Loop Controllers (LC), ESF-CCS Test and Interface Processor (ETIP) and Cabinet Operator Module (COM) and Control Channel Gateway (CCG) etc. GCs in each division are designed to be fully independent triple configuration, which perform system level NSSS and BOP ESFAS logic (2-out-of-4 logic and l-out-of-2 logic, respectively) making it possible to test each GC individually during normal operation. In the existing configuration, the safety-related plant component control is part of the Plant Control System (PCS) non-safety system. For increased safety and reliability, this design change incorporates this part into the LCs, and is therefore designed according to the safety-critical system procedures. The test and diagnosis capabilities of ETIP and COM are reinforced. By means of an automatic periodic test for all main functions of the system, it is possible to quickly determine an abnormal status of the system, and to decrease the elapsed time for tests, thus effectively increasing availability. ESF-CCS consists of four independent divisions (A, B, C, and D) in the Advanced Power Reactor 1400 (APR1400). One prototype division is being manufactured and will be tested

  10. Experience-based design for integrating the patient care experience into healthcare improvement: Identifying a set of reliable emotion words.

    Science.gov (United States)

    Russ, Lauren R; Phillips, Jennifer; Brzozowicz, Keely; Chafetz, Lynne A; Plsek, Paul E; Blackmore, C Craig; Kaplan, Gary S

    2013-12-01

    Experience-based design is an emerging method used to capture the emotional content of patient and family member healthcare experiences, and can serve as the foundation for patient-centered healthcare improvement. However, a core tool-the experience-based design questionnaire-requires words with consistent emotional meaning. Our objective was to identify and evaluate an emotion word set reliably categorized across the demographic spectrum as expressing positive, negative, or neutral emotions for experience-based design improvement work. We surveyed 407 patients, family members, and healthcare workers in 2011. Participants designated each of 67 potential emotion words as positive, neutral, or negative based on their emotional perception of the word. Overall agreement was assessed using the kappa statistic. Words were selected for retention in the final emotion word set based on 80% simple agreement on classification of meaning across subgroups. The participants were 47.9% (195/407) patients, 19.4% (33/407) family members and 32.7% (133/407) healthcare staff. Overall agreement adjusted for chance was moderate (k=0.55). However, agreement for positive (k=0.69) and negative emotions (k=0.68) was substantially higher, while agreement in the neutral category was low (k=0.11). There were 20 positive, 1 neutral, and 14 negative words retained for the final experience-based design emotion word set. We identified a reliable set of emotion words for experience questionnaires to serve as the foundation for patient-centered, experience-based redesign of healthcare. Incorporation of patient and family member perspectives in healthcare requires reliable tools to capture the emotional content of care touch points. Copyright © 2013 Elsevier Inc. All rights reserved.

  11. Cycle chemistry monitoring system as means of improving the reliability of the equipment at the power plants

    Science.gov (United States)

    Yegoshina, O. V.; Voronov, V. N.; Yarovoy, V. O.; Bolshakova, N. A.

    2017-11-01

    There are many problems in domestic energy at the present that require urgent solutions in the near future. One of these problems - the aging of the main and auxiliary equipment. Wear of equipment is the cause of decrease reliability and efficiency of power plants. Reliability of the equipment are associated with the introduction of cycle chemistry monitoring system. The most damageable equipment’s are boilers (52.2 %), turbines (12.6 %) and heating systems (12.3 %) according to the review of failure rate on the power plants. The most part of the damageability of the boiler is heated surfaces (73.2 %). According to the Russian technical requirements, the monitoring systems are responsible to reduce damageability the boiler heating surfaces and to increase the reliability of the equipment. All power units capacity of over 50 MW are equipped with cycle chemistry monitoring systems in order to maintain water chemistry within operating limits. The main idea of cycle chemistry monitoring systems is to improve water chemistry at power plants. According to the guidelines, cycle chemistry monitoring systems of a single unit depends on its type (drum or once-through boiler) and consists of: 20…50 parameters of on-line chemical analyzers; 20…30 «grab» sample analyses (daily) and about 15…20 on-line monitored operating parameters. The operator of modern power plant uses with many data at different points of steam/water cycle. Operators do not can estimate quality of the cycle chemistry due to the large volume of daily and every shift information and dispersion of data, lack of systematization. In this paper, an algorithm for calculating the quality index developed for improving control the water chemistry of the condensate, feed water and prevent scaling and corrosion in the steam/water cycle.

  12. Reliable B cell epitope predictions: impacts of method development and improved benchmarking

    DEFF Research Database (Denmark)

    Kringelum, Jens Vindahl; Lundegaard, Claus; Lund, Ole

    2012-01-01

    biomedical applications such as; rational vaccine design, development of disease diagnostics and immunotherapeutics. However, experimental mapping of epitopes is resource intensive making in silico methods an appealing complementary approach. To date, the reported performance of methods for in silico mapping...... evaluation data set improved from 0.712 to 0.727. Our results thus demonstrate that given proper benchmark definitions, B-cell epitope prediction methods achieve highly significant predictive performances suggesting these tools to be a powerful asset in rational epitope discovery. The updated version...

  13. Improved resolution and reliability in dynamic PET using Bayesian regularization of MRTM2

    DEFF Research Database (Denmark)

    Agn, Mikael; Svarer, Claus; Frokjaer, Vibe G.

    2014-01-01

    This paper presents a mathematical model that regularizes dynamic PET data by using a Bayesian framework. We base the model on the well known two-parameter multilinear reference tissue method MRTM2 and regularize on the assumption that spatially close regions have similar parameters. The developed...... model is compared to the conventional approach of improving the low signal-to-noise ratio of PET data, i.e., spatial filtering of each time frame independently by a Gaussian kernel. We show that the model handles high levels of noise better than the conventional approach, while at the same time...

  14. Improved reliability in skeletal age assessment using a pediatric hand MR scanner with a 0.3T permanent magnet.

    Science.gov (United States)

    Terada, Yasuhiko; Kono, Saki; Uchiumi, Tomomi; Kose, Katsumi; Miyagi, Ryo; Yamabe, Eiko; Fujinaga, Yasunari; Yoshioka, Hiroshi

    2014-01-01

    The purpose of this study was to improve the reliability and validity of skeletal age assessment using an open and compact pediatric hand magnetic resonance (MR) imaging scanner. We used such a scanner with 0.3-tesla permanent magnet to image the left hands of 88 healthy children (aged 3.4 to 15.7 years, mean 8.8 years), and 3 raters (2 orthopedic specialists and a radiologist) assessed skeletal age using those images. We measured the strength of agreement in ratings by values of weighted Cohen's κ and the proportion of cases excluded from rating because of motion artifact and inappropriate positioning. We compared the current results with those of a previous study in which 93 healthy children (aged 4.1 to 16.4 years, mean 9.7 years) were examined with an adult hand scanner. The κ values between raters exceeded 0.80, which indicates almost perfect agreement, and most were higher than those of the previous study. The proportion of cases excluded from rating because of motion artifact or inappropriate positioning was also reduced. The results indicate that use of the compact pediatric hand scanner improved the reliability and validity of skeletal age assessments.

  15. Strategic Factors on Interpreting Remanufacturing Quality-Certifying Framework to Address Warranty Aftermarket for Malaysian Industry

    Science.gov (United States)

    Mohamed, N.; Saman, M. Z. M.; Sharif, S.; Hamzah, H. S.

    2018-03-01

    While the concept of remanufacturing is gaining popularity globally, literature and theory on strategic decision-making on certifying for warranty in this area remain limited. A strategic and establish concept flow is developed based on extensive literature review and surveys with experienced experts who are dealing with remanufactured, reconditioned, rebuilt and reused components. The remanufacturing research on evaluating quality assurance of remanufactured component targets macro-level parameters and the indicators which must be confirmed for evaluation. The strategic remanufacturing factors identified from the literature review are discussed in a brainstorming session with a number of remanufacturing researchers and academic experts. The study is further broadened by industrial surveys and case studies to justify the inputs on developing a framework to certify remanufactured components. Preliminary results have established the key factors of remanufacturing quality control that might lead to the strict quality assurance of remanufactured components. Later, the developed framework can be used as a benchmarking tool to certify remanufactured components and warranty issuance. The findings serve as the foundation for further research concerning Original Equipment Manufacturer (OEM) or Original Equipment Remanufacturer (OER) and Independent Equipment Remanufacturer (IER) in the Malaysian Remanufacturing Industry.

  16. Improvement of Steam Turbine Operational Performance and Reliability with using Modern Information Technologies

    Science.gov (United States)

    Brezgin, V. I.; Brodov, Yu M.; Kultishev, A. Yu

    2017-11-01

    The report presents improvement methods review in the fields of the steam turbine units design and operation based on modern information technologies application. In accordance with the life cycle methodology support, a conceptual model of the information support system during life cycle main stages (LC) of steam turbine unit is suggested. A classifying system, which ensures the creation of sustainable information links between the engineer team (manufacture’s plant) and customer organizations (power plants), is proposed. Within report, the principle of parameterization expansion beyond the geometric constructions at the design and improvement process of steam turbine unit equipment is proposed, studied and justified. The report presents the steam turbine unit equipment design methodology based on the brand new oil-cooler design system that have been developed and implemented by authors. This design system combines the construction subsystem, which is characterized by extensive usage of family tables and templates, and computation subsystem, which includes a methodology for the thermal-hydraulic zone-by-zone oil coolers design calculations. The report presents data about the developed software for operational monitoring, assessment of equipment parameters features as well as its implementation on five power plants.

  17. Application of material databases for improved reliability of reactor pressure vessels

    International Nuclear Information System (INIS)

    Griesbach, T.J.; Server, W.L.; Beaudoin, B.F.; Burgos, B.N.

    1994-01-01

    A vital part of reactor vessel Life Cycle Management program must begin with an accurate characterization of the vessel material properties. Uncertainties in vessel material properties or use of bounding values may result in unnecessary conservatisms in vessel integrity calculations. These conservatisms may be eliminated through a better understanding of the material properties in reactor vessels, both in the unirradiated and irradiated conditions. Reactor vessel material databases are available for quantifying the chemistry and Charpy shift behavior of individual heats of reactor vessel materials. Application of the databases for vessels with embrittlement concerns has proven to be an effective embrittlement management tool. This paper presents details of database development and applications which demonstrate the value of using material databases for improving material chemistry and for maximizing the data from integrated material surveillance programs

  18. Improved and reliable synthesis of 3'-azido-2',3'-dideoxyguanosine derivatives.

    Science.gov (United States)

    Timoshchuk, Victor A; Hogrefe, Richard I; Vaghefi, Morteza M

    2004-01-01

    An improved synthesis of N2-protected-3'-azido-2',3'-dideoxyguanosine 20 and 23 is described. Deoxygenation of 2'-O-alkyl (and/or aryl) sulfonyl-5'-dimethoxytritylguanosine coupled with [1,2]-hydride shift rearrangement gave protected 9-(2-deoxythreo-pentofuranosyl)guanines (10, 12 and 16). This rearrangement was accomplished in high yield with a high degree of stereoselectivity using lithium triisobutylborohydride (L-Selectride). Compounds 10, 12 and 16 were transformed into 3'-O-mesylates (18 and 21), which can be used for 3'-substitution. The 3'-azido nucleosides were obtained by treatment of 18 and 21 with lithium azide. This procedure is reproducible with a good overall yield.

  19. 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.

  20. Improved Mechanical Performance Fracture Properties and Reliability of Radical-Cured Thermosets

    Energy Technology Data Exchange (ETDEWEB)

    Redline, Erica Marie [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bolintineanu, Dan S. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Lane, J. Matthew [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Stevens, Mark J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Alam, Todd M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Celina, Mathias C. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2016-10-01

    The aim of this study was to alter polymerization chemistry to improve network homogeneity in free-radical crosslinked systems. It was hypothesized that a reduction in heterogeneity of the network would lead to improved mechanical performance. Experiments and simulations were carried out to investigate the connection between polymerization chemistry, network structure and mechanical properties. Experiments were conducted on two different monomer systems - the first is a single monomer system, urethane dimethacrylate (UDMA), and the second is a two-monomer system consisting of bisphenol A glycidyl dimethacrylate (BisGMA) and triethylene glycol dimethacrylate (TEGDMA) in a ratio of 70/30 BisGMA/TEGDMA by weight. The methacrylate systems were crosslinked using traditional radical polymeriza- tion (TRP) with azobisisobutyronitrile (AIBN) or benzoyl peroxide (BPO) as an initiator; TRP systems were used as the control. The monomers were also cross-linked using activator regenerated by electron transfer atom transfer radical polymerization (ARGET ATRP) as a type of controlled radical polymerization (CRP). FTIR and DSC were used to monitor reac- tion kinetics of the systems. The networks were analyzed using NMR, DSC, X-ray diffraction (XRD), atomic force microscopy (AFM), and small angle X-ray scattering (SAXS). These techniques were employed in an attempt to quantify differences between the traditional and controlled radical polymerizations. While a quantitative methodology for characterizing net- work morphology was not established, SAXS and AFM have shown some promising initial results. Additionally, differences in mechanical behavior were observed between traditional and controlled radical polymerized thermosets in the BisGMA/TEGDMA system but not in the UDMA materials; this finding may be the result of network ductility variations between the two materials. Coarse-grained molecular dynamics simulations employing a novel model of the CRP reaction were carried out for

  1. 76 FR 52596 - Request for Comment Concerning Interpretations of the Magnuson-Moss Warranty Act; Rule Governing...

    Science.gov (United States)

    2011-08-23

    ... tool for consumers in making a purchasing decision either about the product itself or about buying a... the basis that a warranty must be ``part of the basis of the bargain [to purchase a consumer product... consumer product and the consumer must not give any consideration beyond the purchase price of the consumer...

  2. 48 CFR 227.7203-14 - Conformity, acceptance, and warranty of computer software and computer software documentation.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Conformity, acceptance... Software Documentation 227.7203-14 Conformity, acceptance, and warranty of computer software and computer...) Conformity and acceptance. Solicitations and contracts requiring the delivery of computer software shall...

  3. The effect of plant reliability improvement in the cost of generating electricity

    International Nuclear Information System (INIS)

    Nejat, S.; Sanders, R.C.; Tsoulfanidis, N.

    1982-01-01

    The objective of this investigation is to study the economic benefits in operating a nuclear power plant, as a result of improving the availability of the secondary (steam) loop of the plant. A new method has been developed to obtain availability, frequency of failure, probability and frequency of operation, cycle time, and uptime for different capacity states of a parallel series system having components with failure and repair rates distributed exponentially in time. The method has been applied to different subsystems, systems, and the secondary loop of a plant as a whole. The effect of having spare parts for several components, as measured by savings in the generation of electricity, is also studied. The Kettelle algorithm was applied to determine optimal allocation of spare parts to achieve maximum availability or minimum cost of electricity, subject to a fixed spare parts budget. The savings per year for optimal spare parts allocation and different spare parts budgets were obtained. The results show that the utility will save its customers a large amount of money if spare parts are purchased, especially at the beginning of the plant operation, and are allocated judiciously

  4. Improvement in Device Performance and Reliability of Organic Light-Emitting Diodes through Deposition Rate Control

    Directory of Open Access Journals (Sweden)

    Shun-Wei Liu

    2014-01-01

    Full Text Available We demonstrated a fabrication technique to reduce the driving voltage, increase the current efficiency, and extend the operating lifetime of an organic light-emitting diode (OLED by simply controlling the deposition rate of bis(10-hydroxybenzo[h]qinolinato beryllium (Bebq2 used as the emitting layer and the electron-transport layer. In our optimized device, 55 nm of Bebq2 was first deposited at a faster deposition rate of 1.3 nm/s, followed by the deposition of a thin Bebq2 (5 nm layer at a slower rate of 0.03 nm/s. The Bebq2 layer with the faster deposition rate exhibited higher photoluminescence efficiency and was suitable for use in light emission. The thin Bebq2 layer with the slower deposition rate was used to modify the interface between the Bebq2 and cathode and hence improve the injection efficiency and lower the driving voltage. The operating lifetime of such a two-step deposition OLED was 1.92 and 4.6 times longer than that of devices with a single deposition rate, that is, 1.3 and 0.03 nm/s cases, respectively.

  5. Embedded Sensors and Controls to Improve Component Performance and Reliability -- Bench-scale Testbed Design Report

    Energy Technology Data Exchange (ETDEWEB)

    Melin, Alexander M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Kisner, Roger A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Drira, Anis [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Reed, Frederick K. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-09-01

    Embedded instrumentation and control systems that can operate in extreme environments are challenging due to restrictions on sensors and materials. As a part of the Department of Energy's Nuclear Energy Enabling Technology cross-cutting technology development programs Advanced Sensors and Instrumentation topic, this report details the design of a bench-scale embedded instrumentation and control testbed. The design goal of the bench-scale testbed is to build a re-configurable system that can rapidly deploy and test advanced control algorithms in a hardware in the loop setup. The bench-scale testbed will be designed as a fluid pump analog that uses active magnetic bearings to support the shaft. The testbed represents an application that would improve the efficiency and performance of high temperature (700 C) pumps for liquid salt reactors that operate in an extreme environment and provide many engineering challenges that can be overcome with embedded instrumentation and control. This report will give details of the mechanical design, electromagnetic design, geometry optimization, power electronics design, and initial control system design.

  6. Designing and Assessing the Validity and Reliability of the Hospital Readiness Assessment Tools to Conducting Quality Improvement Program

    Directory of Open Access Journals (Sweden)

    Kamal Gholipoor

    2016-09-01

    Full Text Available Background and objectives : Identifying the readiness of hospital and its strengths and weaknesses can be useful in developing appropriate planning and situation analyses and management to getting effective in clinical audit programs. The aim of this study was to design and assess the validity of the Hospital Readiness Assessment Tools to conduct quality improvement and clinical audit programs. Material and Methods: In this study, based on the results of a systematic review of literature, an initial questionnaire with 77 items was designed. Questionnaire content validity was reviewed by experts in the field of hospital management and quality improvement in Tabriz University of Medical Sciences. For this purpose, 20 questionnaires were sent to experts. Finally, 15 participants returned completed questionnaire. Questionnaire validity was reviewed and confirmed based on Content Validity Index and Content Validity Ratio. Questionnaire reliability was confirmed based on Cronbach's alpha index (α = 0.96 in a pilot study by participation of 30 hospital managers. Results: The results showed that the final questionnaire contains 54 questions as nine category as: data and information (9 items, teamwork (12 questions, resources (5 questions, patient and education (5, intervention design and implementation (5 questions, clinical audit management (4 questions, human resources (6 questions, evidence and standard (4 items and evaluation and feedback (4 items. The final questionnaire content validity index was 0.91 and final questionnaire Cronbach's alpha coefficient was 0.96. Conclusion: Considering the relative good validity and reliability of the designed tool in this study, it appears that the questionnaire can be used to identify and assess the readiness of hospitals for quality improvement and clinical audit program implementation

  7. Near-misses are an opportunity to improve patient safety: adapting strategies of high reliability organizations to healthcare.

    Science.gov (United States)

    Van Spall, Harriette; Kassam, Alisha; Tollefson, Travis T

    2015-08-01

    Near-miss investigations in high reliability organizations (HROs) aim to mitigate risk and improve system safety. Healthcare settings have a higher rate of near-misses and subsequent adverse events than most high-risk industries, but near-misses are not systematically reported or analyzed. In this review, we will describe the strategies for near-miss analysis that have facilitated a culture of safety and continuous quality improvement in HROs. Near-miss analysis is routine and systematic in HROs such as aviation. Strategies implemented in aviation include the Commercial Aviation Safety Team, which undertakes systematic analyses of near-misses, so that findings can be incorporated into Standard Operating Procedures (SOPs). Other strategies resulting from incident analyses include Crew Resource Management (CRM) for enhanced communication, situational awareness training, adoption of checklists during operations, and built-in redundancy within systems. Health care organizations should consider near-misses as opportunities for quality improvement. The systematic reporting and analysis of near-misses, commonplace in HROs, can be adapted to health care settings to prevent adverse events and improve clinical outcomes.

  8. 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.

  9. USING A TOTAL QUALITY STRATEGY IN A NEW PRACTICAL APPROACH FOR IMPROVING THE PRODUCT RELIABILITY IN AUTOMOTIVE INDUSTRY

    Directory of Open Access Journals (Sweden)

    Cristiano Fragassa

    2014-09-01

    Full Text Available In this paper a Total Quality Management strategy is proposed, refined and used with the aim at improving the quality of large-mass industrial products far beyond the technical specifications demanded at the end-customer level. This approach combines standard and non-standard tools used for Reliability, Availability and Maintainability analysis. The procedure also realizes a stricter correlation between theoretical evaluation methods and experimental evidences as part of a modern integrated method for strengthening quality in design and process. A commercial Intake Manifold, largely spread in the market, is used as test-case for the validation of the methodology. As general additional result, the research underlines the impact of Total Quality Management and its tools on the development of innovation.

  10. Application of space and aviation technology to improve the safety and reliability of nuclear power plant operations. Final report

    International Nuclear Information System (INIS)

    1980-04-01

    This report investigates various technologies that have been developed and utilized by the aerospace community, particularly the National Aeronautics and Space Administration (NASA) and the aviation industry, that would appear to have some potential for contributing to improved operational safety and reliability at commercial nuclear power plants of the type being built and operated in the United States today. The main initiator for this study, as well as many others, was the accident at the Three Mile Island (TMI) nuclear power plant in March 1979. Transfer and application of technology developed by NASA, as well as other public and private institutions, may well help to decrease the likelihood of similar incidents in the future

  11. The French nuclear power plant reactor building containment contributions of prestressing and concrete performances in reliability improvements and cost savings

    International Nuclear Information System (INIS)

    Rouelle, P.; Roy, F.

    1998-01-01

    The Electricite de France's N4 CHOOZ B nuclear power plant, two units of the world's largest PWR model (1450 Mwe each), has earned the Electric Power International's 1997 Powerplant Award. This lead NPP for EDF's N4 series has been improved notably in terms of civil works. The presentation will focus on the Reactor Building's inner containment wall which is one of the main civil structures on a technical and safety point of view. In order to take into account the necessary evolution of the concrete technical specification such as compressive strength low creep and shrinkage, the HSC/HPC has been used on the last N4 Civaux 2 NPP. As a result of the use of this type of professional concrete, the containment withstands an higher internal pressure related to severe accident and ensures higher level of leak-tightness, thus improving the overall safety of the NPP. On that occasion, a new type of prestressing has been tested locally through 55 C 15 S tendons using a new C 1500 FE Jack. These updated civil works techniques shall allow EDF to ensure a Reactor Containment lifespan for more than 50 years. The gains in terms of reliability and cost saving of these improved techniques will be developed hereafter

  12. Reliability calculations

    International Nuclear Information System (INIS)

    Petersen, K.E.

    1986-03-01

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

  13. Technologies for improving the availability and reliability of current and future water cooled nuclear power plants. Proceedings of a technical committee meeting

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-11-01

    One of the activities of the IAEA is to provide all Member States with an international source of balanced, objective information on advanced in technology for water cooled reactors. Since the global nuclear industry has a common interest in improving plant availability and reliability to assure specific individual plant and country perspective as well as to have an image of well managed competitive industry, the IAEA held a Technical Committee Meeting on Technologies for Improving the Availability and Reliability of Current and Future Water Cooled Nuclear Power Plants in September 1997. The basic aim to was to identify, review and exchange information on international developments in technologies for achieving high availability and reliability and to suggest areas where further technical advances could contribute to improvement of performance. Designs for future plants were presented in the context of how they can accommodate both the organizational and technical means for reaching even higher levels of performance. This proceedings contains the contributed papers presented at this Meeting each with a separate abstract. Four sessions were concerned with: policies, practices and procedures for achieving high reliability and availability; improving availability and reliability through better use of today`s technologies; recent advances in technologies for improving availability and reliability; achieving high availability for new plants Refs, figs, tabs

  14. Technologies for improving the availability and reliability of current and future water cooled nuclear power plants. Proceedings of a technical committee meeting

    International Nuclear Information System (INIS)

    1998-11-01

    One of the activities of the IAEA is to provide all Member States with an international source of balanced, objective information on advanced in technology for water cooled reactors. Since the global nuclear industry has a common interest in improving plant availability and reliability to assure specific individual plant and country perspective as well as to have an image of well managed competitive industry, the IAEA held a Technical Committee Meeting on Technologies for Improving the Availability and Reliability of Current and Future Water Cooled Nuclear Power Plants in September 1997. The basic aim to was to identify, review and exchange information on international developments in technologies for achieving high availability and reliability and to suggest areas where further technical advances could contribute to improvement of performance. Designs for future plants were presented in the context of how they can accommodate both the organizational and technical means for reaching even higher levels of performance. This proceedings contains the contributed papers presented at this Meeting each with a separate abstract. Four sessions were concerned with: policies, practices and procedures for achieving high reliability and availability; improving availability and reliability through better use of today's technologies; recent advances in technologies for improving availability and reliability; achieving high availability for new plants

  15. Audit Report on the Sacramento Army Depot Internal Review and Audit Compliance Office's "Audits of Warranties, Quality Deficiency Reports, and Reports of Discrepancies"

    National Research Council Canada - National Science Library

    1992-01-01

    The Sacramento Army Depot (SAAD) Internal Review and Audit Compliance Office (Internal Review) issued an audit report, "Audit of Warranties, Quality Deficiency Reports, and Reports of Discrepancies," on July 20, 1990...

  16. The Healthcare Improvement Scotland evidence note rapid review process: providing timely, reliable evidence to inform imperative decisions on healthcare.

    Science.gov (United States)

    McIntosh, Heather M; Calvert, Julie; Macpherson, Karen J; Thompson, Lorna

    2016-06-01

    Rapid review has become widely adopted by health technology assessment agencies in response to demand for evidence-based information to support imperative decisions. Concern about the credibility of rapid reviews and the reliability of their findings has prompted a call for wider publication of their methods. In publishing this overview of the accredited rapid review process developed by Healthcare Improvement Scotland, we aim to raise awareness of our methods and advance the discourse on best practice. Healthcare Improvement Scotland produces rapid reviews called evidence notes using a process that has achieved external accreditation through the National Institute for Health and Care Excellence. Key components include a structured approach to topic selection, initial scoping, considered stakeholder involvement, streamlined systematic review, internal quality assurance, external peer review and updating. The process was introduced in 2010 and continues to be refined over time in response to user feedback and operational experience. Decision-makers value the responsiveness of the process and perceive it as being a credible source of unbiased evidence-based information supporting advice for NHSScotland. Many agencies undertaking rapid reviews are striving to balance efficiency with methodological rigour. We agree that there is a need for methodological guidance and that it should be informed by better understanding of current approaches and the consequences of different approaches to streamlining systematic review methods. Greater transparency in the reporting of rapid review methods is essential to enable that to happen.

  17. Analysis of performance reliability of electrical and electronic equipment of car-tractor

    Directory of Open Access Journals (Sweden)

    Kravchenko О.Р.

    2016-08-01

    Full Text Available The analysis of the operational reliability of electrical and electronic equipment of vehicles, trucks Mercedes-Benz Actros 1844 LS and Volvo FH 1242, conducting international cargo transportation is performed. It is established that the equipment is reliable, which meets modern requirements, but where there is a violation of the resolution. The reason for repair work is constructive and operational factors. Distribution of efficiency and overall performance of operational reliability is retrieved. Items with more bounce are found. Common factors of violation of efficiency cars, trucks in operation, are largely different stages in warranty runs are obtained.

  18. Atomization in a graphite furnace with ballast - a method of improvement of reliability of atomic absorption analysis

    International Nuclear Information System (INIS)

    Katskov, D.A.; Grinshtejn, I.L.

    1978-01-01

    For the purpose of improving the reliability with which elements are determined in atomic absorption analysis with atomization in a graphite furnace, a method is proposed based on the use of a furnace with an extra ballast body. A small cylinder of graphite or refractory metal (Ta) placed in the central part of the furnace, is used as ballast. When in poor heat contact with the wall the ballast is heated by ray emission at a somewhat slower rate than the furnace. It is shown that the kinetics of evaporation of the substance being analysed in the ballast furnace is determined by the rate of change of temperature of the ballast body. As a result of the lag in evaporation, vapour from the analysed substance reaches a zone of a much higher temperature than with evaporation in the usual type furnace, leading to an increase in the degree of atomization. Theoretical analysis establishes the temperature of the ballast, and conditions for the determination of elements (Cd) are optimized. The experiments conducted indicate a considerable decrease in the effect of the composition of the sample on the results of the analysis and a lower molecular interference in the ballast furnace. With high evaporation lag the vapours of the sample reach the zone of practically constant temperature, thus making it possible to use the integral method of absorption registration with absolute accuracy. With fractionated distillation of volatile components of the sample, fractionation is considerably more accurate in a ballast furnace than in the usual type furnace

  19. Study on improvement in reliability of inventory assessment in vitrified waste for long-term safety of geological disposal

    International Nuclear Information System (INIS)

    Ishikawa, Masumi; Kaneko, Satoru; Kitayama, Kazumi; Ishiguro, Katsuhiko; Ueda, Hiroyoshi; Wakasugi, Keiichiro; Shinohara, Nobuo; Okumura, Keisuke; Chino, Masamichi; Moriya, Noriyasu

    2009-01-01

    Since quality control issues for vitrified waste are defined mainly with the focus on the transport and interim storage of the waste rather than the long-term safety of geological disposal, they do not cover inventories of long-lived nuclides that are of most interest in the safety assessment of geological disposal. Therefore, we suggest a flow chart for the assessment of inventories of long-lived nuclides in the vitrified waste focusing on the measured values. This includes an indirect assessment with indicative nuclides that have been already measured in the returned vitrified wastes from abroad. In order to apply this flow chart for commercial operation, its applicability should be examined for cases with a variation in burn-up history and with an uncertainty associated with carry-over fraction at reprocessing. We started an R and D program to examine the applicability as well as to improve the reliability of the nuclide generation/decay code and the nuclear data library using liquid waste from spent fuel with a clear irradiation history. To solve the issue of quality control for vitrified waste, a comprehensive study is needed in aspects not only of geological disposal field but also of operation of a nuclear power plant, reprocessing of spent fuel and vitrification of liquid waste. This study is a pioneering study conducted to integrate them. (author)

  20. Accounting for measurement reliability to improve the quality of inference in dental microhardness research: a worked example.

    Science.gov (United States)

    Sever, Ivan; Klaric, Eva; Tarle, Zrinka

    2016-07-01

    Dental microhardness experiments are influenced by unobserved factors related to the varying tooth characteristics that affect measurement reproducibility. This paper explores the appropriate analytical tools for modeling different sources of unobserved variability to reduce the biases encountered and increase the validity of microhardness studies. The enamel microhardness of human third molars was measured by Vickers diamond. The effects of five bleaching agents-10, 16, and 30 % carbamide peroxide, and 25 and 38 % hydrogen peroxide-were examined, as well as the effect of artificial saliva and amorphous calcium phosphate. To account for both between- and within-tooth heterogeneity in evaluating treatment effects, the statistical analysis was performed in the mixed-effects framework, which also included the appropriate weighting procedure to adjust for confounding. The results were compared to those of the standard ANOVA model usually applied. The weighted mixed-effects model produced the parameter estimates of different magnitude and significance than the standard ANOVA model. The results of the former model were more intuitive, with more precise estimates and better fit. Confounding could seriously bias the study outcomes, highlighting the need for more robust statistical procedures in dental research that account for the measurement reliability. The presented framework is more flexible and informative than existing analytical techniques and may improve the quality of inference in dental research. Reported results could be misleading if underlying heterogeneity of microhardness measurements is not taken into account. The confidence in treatment outcomes could be increased by applying the framework presented.

  1. TCS: a new multiple sequence alignment reliability measure to estimate alignment accuracy and improve phylogenetic tree reconstruction.

    Science.gov (United States)

    Chang, Jia-Ming; Di Tommaso, Paolo; Notredame, Cedric

    2014-06-01

    Multiple sequence alignment (MSA) is a key modeling procedure when analyzing biological sequences. Homology and evolutionary modeling are the most common applications of MSAs. Both are known to be sensitive to the underlying MSA accuracy. In this work, we show how this problem can be partly overcome using the transitive consistency score (TCS), an extended version of the T-Coffee scoring scheme. Using this local evaluation function, we show that one can identify the most reliable portions of an MSA, as judged from BAliBASE and PREFAB structure-based reference alignments. We also show how this measure can be used to improve phylogenetic tree reconstruction using both an established simulated data set and a novel empirical yeast data set. For this purpose, we describe a novel lossless alternative to site filtering that involves overweighting the trustworthy columns. Our approach relies on the T-Coffee framework; it uses libraries of pairwise alignments to evaluate any third party MSA. Pairwise projections can be produced using fast or slow methods, thus allowing a trade-off between speed and accuracy. We compared TCS with Heads-or-Tails, GUIDANCE, Gblocks, and trimAl and found it to lead to significantly better estimates of structural accuracy and more accurate phylogenetic trees. The software is available from www.tcoffee.org/Projects/tcs. © The Author 2014. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  2. Comprehensive automation and monitoring of MV grids as the key element of improvement of energy supply reliability and continuity

    Directory of Open Access Journals (Sweden)

    Stanisław Kubacki

    2012-03-01

    Full Text Available The paper presents the issue of comprehensive automation and monitoring of medium voltage (MV grids as a key element of the Smart Grid concept. The existing condition of MV grid control and monitoring is discussed, and the concept of a solution which will provide the possibility of remote automatic grid reconfiguration and ensure full grid observability from the dispatching system level is introduced. Automation of MV grid switching is discussed in detail to isolate a faulty line section and supply electricity at the time of the failure to the largest possible number of recipients. An example of such automation controls’ operation is also presented. The paper’s second part presents the key role of the quick fault location function and the possibility of the MV grid’s remote reconfiguration for improving power supply reliability (SAIDI and SAIFI indices. It is also shown how an increase in the number of points fitted with faulted circuit indicators with the option of remote control of switches from the dispatch system in MV grids may affect reduction of SAIDI and SAIFI indices across ENERGA-OPERATOR SA divisions.

  3. 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.

  4. METHODS OF IMPROVING THE RELIABILITY OF THE CONTROL SYSTEM TRACTION POWER SUPPLY OF ELECTRIC TRANSPORT BASED ON AN EXPERT INFORMATION

    Directory of Open Access Journals (Sweden)

    O. O. Matusevych

    2009-03-01

    Full Text Available The author proposed the numerous methods of solving the multi-criterion task – increasing of reliability of control system on the basis of expert information. The information, which allows choosing thoughtfully the method of reliability increasing for a control system of electric transport, is considered.

  5. Improvement of Matrix Converter Drive Reliability by Online Fault Detection and a Fault-Tolerant Switching Strategy

    DEFF Research Database (Denmark)

    Nguyen-Duy, Khiem; Liu, Tian-Hua; Chen, Der-Fa

    2011-01-01

    The matrix converter system is becoming a very promising candidate to replace the conventional two-stage ac/dc/ac converter, but system reliability remains an open issue. The most common reliability problem is that a bidirectional switch has an open-switch fault during operation. In this paper, a...

  6. An alternative to the balance error scoring system: using a low-cost balance board to improve the validity/reliability of sports-related concussion balance testing.

    Science.gov (United States)

    Chang, Jasper O; Levy, Susan S; Seay, Seth W; Goble, Daniel J

    2014-05-01

    Recent guidelines advocate sports medicine professionals to use balance tests to assess sensorimotor status in the management of concussions. The present study sought to determine whether a low-cost balance board could provide a valid, reliable, and objective means of performing this balance testing. Criterion validity testing relative to a gold standard and 7 day test-retest reliability. University biomechanics laboratory. Thirty healthy young adults. Balance ability was assessed on 2 days separated by 1 week using (1) a gold standard measure (ie, scientific grade force plate), (2) a low-cost Nintendo Wii Balance Board (WBB), and (3) the Balance Error Scoring System (BESS). Validity of the WBB center of pressure path length and BESS scores were determined relative to the force plate data. Test-retest reliability was established based on intraclass correlation coefficients. Composite scores for the WBB had excellent validity (r = 0.99) and test-retest reliability (R = 0.88). Both the validity (r = 0.10-0.52) and test-retest reliability (r = 0.61-0.78) were lower for the BESS. These findings demonstrate that a low-cost balance board can provide improved balance testing accuracy/reliability compared with the BESS. This approach provides a potentially more valid/reliable, yet affordable, means of assessing sports-related concussion compared with current methods.

  7. Basic Study on Term of Warranty Liability for Water Supply, Drainage, and Sanitation Arrangement Work Defect in Apartment Building

    Science.gov (United States)

    Park, Junmo; Seo, DeokSeok

    2017-06-01

    The defect lawsuit of the apartment which is the representative residential style of Korea continues and becomes a social problem. In the defect lawsuit, the term of warranty liability is a period that can demand the defect repair according to defect occurrence, and the exclusion period of the exercise of rights. However, the term of warranty liability stipulated in relevant laws such as Enforcement Decree of the Housing Act is being changed arbitrarily, without any established grounds. Therefore, a reasonable standard for establishing the term of warranty liability is required. In this study, the defects of water supply, drainage and sanitation arrangement work were studied. As a result of analyzing the number of defect occurrence in the apartment, it was shown that the defects in water supply, drainage and sanitation arrangement work occurred more than 80% in the 1st ∼ 2nd year after completion. However, the occurrence of defects from the 3rd year was extremely slight. On the other hand, it was confirmed that the defect occurrence continued until fairly late point of time as the end point of time of the defects was in the 7th to 9th years.

  8. Improving the Reliability of Network Metrics in Structural Brain Networks by Integrating Different Network Weighting Strategies into a Single Graph

    Directory of Open Access Journals (Sweden)

    Stavros I. Dimitriadis

    2017-12-01

    Full Text Available Structural brain networks estimated from diffusion MRI (dMRI via tractography have been widely studied in healthy controls and patients with neurological and psychiatric diseases. However, few studies have addressed the reliability of derived network metrics both node-specific and network-wide. Different network weighting strategies (NWS can be adopted to weight the strength of connection between two nodes yielding structural brain networks that are almost fully-weighted. Here, we scanned five healthy participants five times each, using a diffusion-weighted MRI protocol and computed edges between 90 regions of interest (ROI from the Automated Anatomical Labeling (AAL template. The edges were weighted according to nine different methods. We propose a linear combination of these nine NWS into a single graph using an appropriate diffusion distance metric. We refer to the resulting weighted graph as an Integrated Weighted Structural Brain Network (ISWBN. Additionally, we consider a topological filtering scheme that maximizes the information flow in the brain network under the constraint of the overall cost of the surviving connections. We compared each of the nine NWS and the ISWBN based on the improvement of: (a intra-class correlation coefficient (ICC of well-known network metrics, both node-wise and per network level; and (b the recognition accuracy of each subject compared to the remainder of the cohort, as an attempt to access the uniqueness of the structural brain network for each subject, after first applying our proposed topological filtering scheme. Based on a threshold where the network level ICC should be >0.90, our findings revealed that six out of nine NWS lead to unreliable results at the network level, while all nine NWS were unreliable at the node level. In comparison, our proposed ISWBN performed as well as the best performing individual NWS at the network level, and the ICC was higher compared to all individual NWS at the node

  9. 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.

  10. Improving the quality of discrete-choice experiments in health: how can we assess validity and reliability?

    Science.gov (United States)

    Janssen, Ellen M; Marshall, Deborah A; Hauber, A Brett; Bridges, John F P

    2017-12-01

    The recent endorsement of discrete-choice experiments (DCEs) and other stated-preference methods by regulatory and health technology assessment (HTA) agencies has placed a greater focus on demonstrating the validity and reliability of preference results. Areas covered: We present a practical overview of tests of validity and reliability that have been applied in the health DCE literature and explore other study qualities of DCEs. From the published literature, we identify a variety of methods to assess the validity and reliability of DCEs. We conceptualize these methods to create a conceptual model with four domains: measurement validity, measurement reliability, choice validity, and choice reliability. Each domain consists of three categories that can be assessed using one to four procedures (for a total of 24 tests). We present how these tests have been applied in the literature and direct readers to applications of these tests in the health DCE literature. Based on a stakeholder engagement exercise, we consider the importance of study characteristics beyond traditional concepts of validity and reliability. Expert commentary: We discuss study design considerations to assess the validity and reliability of a DCE, consider limitations to the current application of tests, and discuss future work to consider the quality of DCEs in healthcare.

  11. The validity and reliability of the StationMaster: a device to improve the accuracy of station assessment in labour.

    Science.gov (United States)

    Awan, Noveen; Rhoades, Anthony; Weeks, Andrew D

    2009-07-01

    To compare the accuracy of digital assessment and the StationMaster (SM) in the assessment of fetal head station. The SM is a simple modification of the amniotomy hook which works by relocating the point of reference for station assessment from the ischial spines to the posterior fourchette. It is first adjusted to the woman's pelvic size, and then inserted into the vagina until it touches the fetal head. The station is then read off at the posterior fourchette in cm. An in vitro study of test validity and reliability was conducted at Liverpool Women's Hospital, Liverpool, UK. An apparatus was constructed in which a model fetal head could be accurately positioned within a mannequin's pelvis. Twenty midwives and 20 doctors (in current labour ward practice) gave their consent to take part. First, the head was placed in 5 random stations (-2 to +7 cm) and the participant asked to record their digital assessment for each. The participant was then taught to use the SM and the experiment repeated with 5 new stations. The complete experiment was repeated at least 2 weeks later using the same stations but in reverse order. The true values were compared with both the digital and SM assessments using mean differences with 95% limits of agreement. The repeatability of the two methods was assessed in the same way. Overall, the SM was more accurate than digital examination. The mean error (S.D.) ranged from 0.1 (1.2) to 2.6 (1.6) for the StationMaster and 0.3 (1.3) to 4.3 (1.1) for digital examination. Inaccuracies increased as the head descended through the pelvis. When assessed digitally, the true value fell outside one standard deviation for stations of more than +1cm. In contrast, with the SM the true value remained inside one standard deviation for all stations up to +5. In vitro the SM improves the accuracy of intrapartum station assessment.

  12. Introducing the MINDER research project: Methodologies for Improvement of Non-residential buildings' Daily Energy Efficiency Reliability

    OpenAIRE

    Berker, Thomas; Gansmo, Helen Jøsok; Junghans, Antje

    2014-01-01

    In the Norwegian building sector, we are currently witnessing the transition from a realization gap - the gap between availability of solutions and their implementation - to a reliability gap: the gap between the building's potential performances as it is commissioned to its users and its actual performance in daily use. When new solutions do not live up to their promises, not only the performance of the individual building is at stake. The reliability gap can easily grow into a credibility g...

  13. Power electronics reliability analysis.

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Mark A.; Atcitty, Stanley

    2009-12-01

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

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

    International Nuclear Information System (INIS)

    Shalev, Dan M.; Tiran, Joseph

    2007-01-01

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

  15. Improving the Efficiency of Administrative Decision-Making when Monitoring Reliability and Safety of Oil and Gas Equipment

    Directory of Open Access Journals (Sweden)

    Zemenkova Maria

    2016-01-01

    Full Text Available Methodology of rapid assessment of reliability index was developed based on system analysis of technological parameters. Within functioning of on-line monitoring system of reliability index of industrial facility this method allows to increase efficiency of making managerial decisions on technical and preventive maintenance. The technique is based on the analysis of technological parameters of operational modes of pipeline transport facilities registered by dispatcher controls. The created technique can be used by the operating, research, design institutes and oil and gas transport enterprises when declaring industrial safety. The received mathematical models allow federal services of supervision, the independent expert organizations to predict the development of reliability in the registered block of dispatching data either in real time mode, or taking into account the dynamics of service conditions of the object.

  16. Improved Iterative Hard- and Soft-Reliability Based Majority-Logic Decoding Algorithms for Non-Binary Low-Density Parity-Check Codes

    Science.gov (United States)

    Xiong, Chenrong; Yan, Zhiyuan

    2014-10-01

    Non-binary low-density parity-check (LDPC) codes have some advantages over their binary counterparts, but unfortunately their decoding complexity is a significant challenge. The iterative hard- and soft-reliability based majority-logic decoding algorithms are attractive for non-binary LDPC codes, since they involve only finite field additions and multiplications as well as integer operations and hence have significantly lower complexity than other algorithms. In this paper, we propose two improvements to the majority-logic decoding algorithms. Instead of the accumulation of reliability information in the existing majority-logic decoding algorithms, our first improvement is a new reliability information update. The new update not only results in better error performance and fewer iterations on average, but also further reduces computational complexity. Since existing majority-logic decoding algorithms tend to have a high error floor for codes whose parity check matrices have low column weights, our second improvement is a re-selection scheme, which leads to much lower error floors, at the expense of more finite field operations and integer operations, by identifying periodic points, re-selecting intermediate hard decisions, and changing reliability information.

  17. Does a web-based feedback training program result in improved reliability in clinicians' ratings of the Global Assessment of Functioning (GAF) Scale?

    Science.gov (United States)

    Støre-Valen, Jakob; Ryum, Truls; Pedersen, Geir A F; Pripp, Are H; Jose, Paul E; Karterud, Sigmund

    2015-09-01

    The Global Assessment of Functioning (GAF) Scale is used in routine clinical practice and research to estimate symptom and functional severity and longitudinal change. Concerns about poor interrater reliability have been raised, and the present study evaluated the effect of a Web-based GAF training program designed to improve interrater reliability in routine clinical practice. Clinicians rated up to 20 vignettes online, and received deviation scores as immediate feedback (i.e., own scores compared with expert raters) after each rating. Growth curves of absolute SD scores across the vignettes were modeled. A linear mixed effects model, using the clinician's deviation scores from expert raters as the dependent variable, indicated an improvement in reliability during training. Moderation by content of scale (symptoms; functioning), scale range (average; extreme), previous experience with GAF rating, profession, and postgraduate training were assessed. Training reduced deviation scores for inexperienced GAF raters, for individuals in clinical professions other than nursing and medicine, and for individuals with no postgraduate specialization. In addition, training was most beneficial for cases with average severity of symptoms compared with cases with extreme severity. The results support the use of Web-based training with feedback routines as a means to improve the reliability of GAF ratings performed by clinicians in mental health practice. These results especially pertain to clinicians in mental health practice who do not have a masters or doctoral degree. (c) 2015 APA, all rights reserved.

  18. Contribution to improving reliability assessments of mechanical structural components requiring a high degree of safety using weighted Monte Carlo simulation

    Energy Technology Data Exchange (ETDEWEB)

    Kutter, R

    1981-12-04

    Physical theories to inquire lifetime and reliability of mechanical structures or components under multiscale random stress do not exist. Today those dates were examinated e.g. in development of aircrafts and motorcars by fatigue-testing of original components and sections during long terms. Knowing the distributions of stress and material-parameters the same testing is to be realized simulationary on highspeed computers. This study gives methods to reduce the necessary computation time to attending ones even to proof reliability up to R=1-10/sup -9/. These methods were of Monte-Carlo-Simulation with weighted parameters and respect to life-history.

  19. 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)

  20. Improvement of level-1 PSA computer code package - Modeling and analysis for dynamic reliability of nuclear power plants

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Chang Hoon; Baek, Sang Yeup; Shin, In Sup; Moon, Shin Myung; Moon, Jae Phil; Koo, Hoon Young; Kim, Ju Shin [Seoul National University, Seoul (Korea, Republic of); Hong, Jung Sik [Seoul National Polytechnology University, Seoul (Korea, Republic of); Lim, Tae Jin [Soongsil University, Seoul (Korea, Republic of)

    1996-08-01

    The objective of this project is to develop a methodology of the dynamic reliability analysis for NPP. The first year`s research was focused on developing a procedure for analyzing failure data of running components and a simulator for estimating the reliability of series-parallel structures. The second year`s research was concentrated on estimating the lifetime distribution and PM effect of a component from its failure data in various cases, and the lifetime distribution of a system with a particular structure. Computer codes for performing these jobs were also developed. The objectives of the third year`s research is to develop models for analyzing special failure types (CCFs, Standby redundant structure) that were nor considered in the first two years, and to complete a methodology of the dynamic reliability analysis for nuclear power plants. The analysis of failure data of components and related researches for supporting the simulator must be preceded for providing proper input to the simulator. Thus this research is divided into three major parts. 1. Analysis of the time dependent life distribution and the PM effect. 2. Development of a simulator for system reliability analysis. 3. Related researches for supporting the simulator : accelerated simulation analytic approach using PH-type distribution, analysis for dynamic repair effects. 154 refs., 5 tabs., 87 figs. (author)

  1. Measurement of the Inter-Rater Reliability Rate Is Mandatory for Improving the Quality of a Medical Database: Experience with the Paulista Lung Cancer Registry.

    Science.gov (United States)

    Lauricella, Leticia L; Costa, Priscila B; Salati, Michele; Pego-Fernandes, Paulo M; Terra, Ricardo M

    2018-06-01

    Database quality measurement should be considered a mandatory step to ensure an adequate level of confidence in data used for research and quality improvement. Several metrics have been described in the literature, but no standardized approach has been established. We aimed to describe a methodological approach applied to measure the quality and inter-rater reliability of a regional multicentric thoracic surgical database (Paulista Lung Cancer Registry). Data from the first 3 years of the Paulista Lung Cancer Registry underwent an audit process with 3 metrics: completeness, consistency, and inter-rater reliability. The first 2 methods were applied to the whole data set, and the last method was calculated using 100 cases randomized for direct auditing. Inter-rater reliability was evaluated using percentage of agreement between the data collector and auditor and through calculation of Cohen's κ and intraclass correlation. The overall completeness per section ranged from 0.88 to 1.00, and the overall consistency was 0.96. Inter-rater reliability showed many variables with high disagreement (>10%). For numerical variables, intraclass correlation was a better metric than inter-rater reliability. Cohen's κ showed that most variables had moderate to substantial agreement. The methodological approach applied to the Paulista Lung Cancer Registry showed that completeness and consistency metrics did not sufficiently reflect the real quality status of a database. The inter-rater reliability associated with κ and intraclass correlation was a better quality metric than completeness and consistency metrics because it could determine the reliability of specific variables used in research or benchmark reports. This report can be a paradigm for future studies of data quality measurement. Copyright © 2018 American College of Surgeons. Published by Elsevier Inc. All rights reserved.

  2. The DASS-14: Improving the Construct Validity and Reliability of the Depression, Anxiety, and Stress Scale in a Cohort of Health Professionals.

    Science.gov (United States)

    Wise, Frances M; Harris, Darren W; Olver, John H

    2017-01-01

    Considerable research has been undertaken in evaluating the DASS-21 in a variety of clinical populations, but studies of the instrument's psychometric adequacy in healthcare professionals is lacking. This study aimed to establish and improve the construct validity and reliability of the DASS-21 in a cohort of Australian health professionals. 343 rehabilitation health professionals completed the DASS-21, along with a demographic questionnaire. Principal components analysis was performed to identify potential factors in the DASS-21. Factors were interpreted against theoretical constructs underlying the instrument. Items loading on separate factors were then subjected to reliability analysis to determine internal consistency of subscales. Items that demonstrated poor fit, or loaded onto more than one factor, were deleted to maximise the reliability of each subscale. Principal components analysis identified three dimensions (depression, anxiety, stress) in a modified version of the DASS-21 (renamed DASS-14), with appropriate construct validity and good reliability (a=0.73 to 0.88). The three dimensions accounted for over 62% of variance between items. The modified DASS-14 scale is a more parsimonious measure of depression, anxiety, and stress, with acceptable reliability and construct validity, in rehabilitation health professionals and is appropriate for use in studies of similar populations.

  3. Electrical Performance and Reliability Improvement of Amorphous-Indium-Gallium-Zinc-Oxide Thin-Film Transistors with HfO2 Gate Dielectrics by CF4 Plasma Treatment

    Science.gov (United States)

    Fan, Ching-Lin; Tseng, Fan-Ping; Tseng, Chiao-Yuan

    2018-01-01

    In this work, amorphous indium-gallium-zinc oxide thin-film transistors (a-IGZO TFTs) with a HfO2 gate insulator and CF4 plasma treatment was demonstrated for the first time. Through the plasma treatment, both the electrical performance and reliability of the a-IGZO TFT with HfO2 gate dielectric were improved. The carrier mobility significantly increased by 80.8%, from 30.2 cm2/V∙s (without treatment) to 54.6 cm2/V∙s (with CF4 plasma treatment), which is due to the incorporated fluorine not only providing an extra electron to the IGZO, but also passivating the interface trap density. In addition, the reliability of the a-IGZO TFT with HfO2 gate dielectric has also been improved by the CF4 plasma treatment. By applying the CF4 plasma treatment to the a-IGZO TFT, the hysteresis effect of the device has been improved and the device’s immunity against moisture from the ambient atmosphere has been enhanced. It is believed that the CF4 plasma treatment not only significantly improves the electrical performance of a-IGZO TFT with HfO2 gate dielectric, but also enhances the device’s reliability. PMID:29772767

  4. Electrical Performance and Reliability Improvement of Amorphous-Indium-Gallium-Zinc-Oxide Thin-Film Transistors with HfO2 Gate Dielectrics by CF4 Plasma Treatment

    Directory of Open Access Journals (Sweden)

    Ching-Lin Fan

    2018-05-01

    Full Text Available In this work, amorphous indium-gallium-zinc oxide thin-film transistors (a-IGZO TFTs with a HfO2 gate insulator and CF4 plasma treatment was demonstrated for the first time. Through the plasma treatment, both the electrical performance and reliability of the a-IGZO TFT with HfO2 gate dielectric were improved. The carrier mobility significantly increased by 80.8%, from 30.2 cm2/V∙s (without treatment to 54.6 cm2/V∙s (with CF4 plasma treatment, which is due to the incorporated fluorine not only providing an extra electron to the IGZO, but also passivating the interface trap density. In addition, the reliability of the a-IGZO TFT with HfO2 gate dielectric has also been improved by the CF4 plasma treatment. By applying the CF4 plasma treatment to the a-IGZO TFT, the hysteresis effect of the device has been improved and the device’s immunity against moisture from the ambient atmosphere has been enhanced. It is believed that the CF4 plasma treatment not only significantly improves the electrical performance of a-IGZO TFT with HfO2 gate dielectric, but also enhances the device’s reliability.

  5. Electrical Performance and Reliability Improvement of Amorphous-Indium-Gallium-Zinc-Oxide Thin-Film Transistors with HfO₂ Gate Dielectrics by CF₄ Plasma Treatment.

    Science.gov (United States)

    Fan, Ching-Lin; Tseng, Fan-Ping; Tseng, Chiao-Yuan

    2018-05-17

    In this work, amorphous indium-gallium-zinc oxide thin-film transistors (a-IGZO TFTs) with a HfO₂ gate insulator and CF₄ plasma treatment was demonstrated for the first time. Through the plasma treatment, both the electrical performance and reliability of the a-IGZO TFT with HfO₂ gate dielectric were improved. The carrier mobility significantly increased by 80.8%, from 30.2 cm²/V∙s (without treatment) to 54.6 cm²/V∙s (with CF₄ plasma treatment), which is due to the incorporated fluorine not only providing an extra electron to the IGZO, but also passivating the interface trap density. In addition, the reliability of the a-IGZO TFT with HfO₂ gate dielectric has also been improved by the CF₄ plasma treatment. By applying the CF₄ plasma treatment to the a-IGZO TFT, the hysteresis effect of the device has been improved and the device's immunity against moisture from the ambient atmosphere has been enhanced. It is believed that the CF₄ plasma treatment not only significantly improves the electrical performance of a-IGZO TFT with HfO₂ gate dielectric, but also enhances the device's reliability.

  6. Improving the reliability of Class 1E power distribution to instrumentation and control cabinets on nuclear power plants in the USA. Final report

    International Nuclear Information System (INIS)

    Brennen, M.B.

    1995-09-01

    This study was conducted to explore nontraditional electric power distribution concepts to improve the reliability of uninterruptible power to vital Instrumentation and Control (I and C) cabinets in future US nuclear power plants. The study incorporated comparative technical and economic evaluations of existing and nontraditional uninterruptible power supply (UPS) concepts. All nontraditional distribution concepts were based on available or already emerging components or semiconductor devices. Another purpose of the study was to reduce the cost and complexity of present power distribution and to lower maintenance, replacement, degradation and fault location requirements. The possible reduction of distribution losses, especially during operation under battery power, was also evaluated. The study indicates that direct current distribution at 48 or 125 Vdc levels would have more than an order of magnitude improvement over the reliability of present alternating current supplies at comparable cost. Furthermore, losses under battery power could be reduced significantly with respect to present distribution losses. An inherent advantage of DC distribution is that power transfer from the failed power bus to an operational bus occurs naturally and instantaneously via two simple and reliable semiconductor diodes. AC distribution, on the other hand, requires complex synchronization, decision making and gated semiconductor switching devices for power bus transfer all of which could be eliminated. Some of the concepts presented may also be applied to make existing vital (Class 1E) uninterruptible power supplies in US nuclear plants more reliable

  7. The Use of Redundancy to Improve Reliability of Deep Space Missions Using Stirling Radioisotope Generator Power Sources

    Science.gov (United States)

    Bolotin, Gary; Everline, Chet; Schmitz, Paul; Distefano, Sal

    2014-01-01

    This study will look at the 140 We class generator as originally envisioned for the ASRG and a larger generator that is scaled up to use four times the fuel. The results discussed below quantify the effect of the use of smaller generators and indicates that a scheme that makes use of several smaller generators enhances the system reliability and allows for more graceful degradation.

  8. Improvement of the reliability of the emergency diesel generators and their protections as a part of the modernization program for units 5 and 6 of the Kozloduy NPP

    International Nuclear Information System (INIS)

    Bogdanov, D.

    2003-01-01

    The measure 'Improvement of the reliability of the emergency diesel generators and their protections' 28411 is part of the modernization program for Units 5 and 6 of Kozloduy NPP. The scope of the measure includes complete change of the I and C system, the local control panels, the technological and electrical protections of the DG set, the excitation system and some of the power distribution switchboards. The new I and C system will be Teleperm XS type, produced by Framatome ANP, the power distribution switchboards type Sivacon, the excitation system Thyripart, and the electrical protection and synchronization system will be provided by Siemens. The purpose of the measure is to increase the availability, maintainability and to improve the reliability of the DG sets

  9. Study on the improvement of the reliability of solar cells on polymer substrates; Etude et amelioration de la fiabilite des cellules solaires sur substrats polymeres

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, D.; Ziegler, Y.; Closset, A.

    2004-07-01

    This final report for the Swiss Federal Office of Energy (SFOE) presents the results of work done on the improvement of the long-term reliability of flexible solar cells deposited on polyimide substrates. Several possibilities were explored simultaneously, including vacuum-de-gassing of the polyimide film, the prevention of water absorption by using diffusion barriers and the reduction of mechanical stress in the thin silicon layers. Work completed is described, including the adaptation of the deposition system, the structuring of metal coatings and improvements to existing equipment to reduce defects caused by dust. The continual effort being made to stabilise the production process and make it economically viable is noted.

  10. Improving the communication reliability of body sensor networks based on the IEEE 802.15.4 protocol.

    Science.gov (United States)

    Gomes, Diogo; Afonso, José A

    2014-03-01

    Body sensor networks (BSNs) enable continuous monitoring of patients anywhere, with minimum constraints to daily life activities. Although the IEEE 802.15.4 and ZigBee(®) (ZigBee Alliance, San Ramon, CA) standards were mainly developed for use in wireless sensors network (WSN) applications, they are also widely used in BSN applications because of device characteristics such as low power, low cost, and small form factor. However, compared with WSNs, BSNs present some very distinctive characteristics in terms of traffic and mobility patterns, heterogeneity of the nodes, and quality of service requirements. This article evaluates the suitability of the carrier sense multiple access-collision avoidance protocol, used by the IEEE 802.15.4 and ZigBee standards, for data-intensive BSN applications, through the execution of experimental tests in different evaluation scenarios, in order to take into account the effects of contention, clock drift, and hidden nodes on the communication reliability. Results show that the delivery ratio may decrease substantially during transitory periods, which can last for several minutes, to a minimum of 90% with retransmissions and 13% without retransmissions. This article also proposes and evaluates the performance of the BSN contention avoidance mechanism, which was designed to solve the identified reliability problems. This mechanism was able to restore the delivery ratio to 100% even in the scenario without retransmissions.

  11. Modernization of Kozloduy nuclear plant unit 5 and 6, implementation of measures to improve the reliability of the main generator system

    International Nuclear Information System (INIS)

    Stinshoff, H.

    2003-01-01

    To improve the reliability of Kozloduy Nuclear power plant several modernization measures will be implemented during the outages in the years 2003 to 2005. In the area of the main generator the following measures will be performed in unit 6 during 2003 outage: - Replacement of main generator circuit breaker by new SF6 cooled breaker type - Replacement of main generator excitation system by new two channel digital system - Replacement of main generator protection by new digital multi-purpose protections including digital fault recorders - Installation of radio frequency monitoring system of main generator circuit Starting from the present situation the new concept is explained. The project organization under consideration of large Bulgarian participation as well as the sequence and schedule of the implementation during the short outage time window is shown. These modernization measures lead to an increase of reliability and availability for the operation of the power plant and with this to increase power plant safety

  12. 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

  13. Improving the reliability of POD curves in NDI methods using a Bayesian inversion approach for uncertainty quantification

    Science.gov (United States)

    Ben Abdessalem, A.; Jenson, F.; Calmon, P.

    2016-02-01

    This contribution provides an example of the possible advantages of adopting a Bayesian inversion approach to uncertainty quantification in nondestructive inspection methods. In such problem, the uncertainty associated to the random parameters is not always known and needs to be characterised from scattering signal measurements. The uncertainties may then correctly propagated in order to determine a reliable probability of detection curve. To this end, we establish a general Bayesian framework based on a non-parametric maximum likelihood function formulation and some priors from expert knowledge. However, the presented inverse problem is time-consuming and computationally intensive. To cope with this difficulty, we replace the real model by a surrogate one in order to speed-up the model evaluation and to make the problem to be computationally feasible for implementation. The least squares support vector regression is adopted as metamodelling technique due to its robustness to deal with non-linear problems. We illustrate the usefulness of this methodology through the control of tube with enclosed defect using ultrasonic inspection method.

  14. Improved Efficiency and Reliability of NGS Amplicon Sequencing Data Analysis for Genetic Diagnostic Procedures Using AGSA Software

    Directory of Open Access Journals (Sweden)

    Axel Poulet

    2016-01-01

    Full Text Available Screening for BRCA mutations in women with familial risk of breast or ovarian cancer is an ideal situation for high-throughput sequencing, providing large amounts of low cost data. However, 454, Roche, and Ion Torrent, Thermo Fisher, technologies produce homopolymer-associated indel errors, complicating their use in routine diagnostics. We developed software, named AGSA, which helps to detect false positive mutations in homopolymeric sequences. Seventy-two familial breast cancer cases were analysed in parallel by amplicon 454 pyrosequencing and Sanger dideoxy sequencing for genetic variations of the BRCA genes. All 565 variants detected by dideoxy sequencing were also detected by pyrosequencing. Furthermore, pyrosequencing detected 42 variants that were missed with Sanger technique. Six amplicons contained homopolymer tracts in the coding sequence that were systematically misread by the software supplied by Roche. Read data plotted as histograms by AGSA software aided the analysis considerably and allowed validation of the majority of homopolymers. As an optimisation, additional 250 patients were analysed using microfluidic amplification of regions of interest (Access Array Fluidigm of the BRCA genes, followed by 454 sequencing and AGSA analysis. AGSA complements a complete line of high-throughput diagnostic sequence analysis, reducing time and costs while increasing reliability, notably for homopolymer tracts.

  15. Reliability Study of Solder Paste Alloy for the Improvement of Solder Joint at Surface Mount Fine-Pitch Components

    Directory of Open Access Journals (Sweden)

    Mohd Nizam Ab. Rahman

    2014-12-01

    Full Text Available The significant increase in metal costs has forced the electronics industry to provide new materials and methods to reduce costs, while maintaining customers’ high-quality expectations. This paper considers the problem of most electronic industries in reducing costly materials, by introducing a solder paste with alloy composition tin 98.3%, silver 0.3%, and copper 0.7%, used for the construction of the surface mount fine-pitch component on a Printing Wiring Board (PWB. The reliability of the solder joint between electronic components and PWB is evaluated through the dynamic characteristic test, thermal shock test, and Taguchi method after the printing process. After experimenting with the dynamic characteristic test and thermal shock test with 20 boards, the solder paste was still able to provide a high-quality solder joint. In particular, the Taguchi method is used to determine the optimal control parameters and noise factors of the Solder Printer (SP machine, that affects solder volume and solder height. The control parameters include table separation distance, squeegee speed, squeegee pressure, and table speed of the SP machine. The result shows that the most significant parameter for the solder volume is squeegee pressure (2.0 mm, and the solder height is the table speed of the SP machine (2.5 mm/s.

  16. Interface Assignment-Based AODV Routing Protocol to Improve Reliability in Multi-Interface Multichannel Wireless Mesh Networks

    Directory of Open Access Journals (Sweden)

    Won-Suk Kim

    2015-01-01

    Full Text Available The utilization of wireless mesh networks (WMNs has greatly increased, and the multi-interface multichannel (MIMC technic has been widely used for the backbone network. Unfortunately, the ad hoc on-demand distance vector (AODV routing protocol defined in the IEEE 802.11s standard was designed for WMNs using the single-interface single-channel technic. So, we define a problem that happens when the legacy AODV is used in MIMC WMNs and propose an interface assignment-based AODV (IA-AODV in order to resolve that problem. IA-AODV, which is based on multitarget path request, consists of the PREQ prediction scheme, the PREQ loss recovery scheme, and the PREQ sender assignment scheme. A detailed operation according to various network conditions and services is introduced, and the routing efficiency and network reliability of a network using IA-AODV are analyzed over the presented system model. Finally, after a real-world test-bed for MIMC WMNs using the IA-AODV routing protocol is implemented, the various indicators of the network are evaluated through experiments. When the proposed routing protocol is compared with the existing AODV routing protocol, it performs the path update using only 14.33% of the management frames, completely removes the routing malfunction, and reduces the UDP packet loss ratio by 0.0012%.

  17. Improvement of fuel-element reliability by insertion of UO2 microspheres in the gap between pellet and clad

    International Nuclear Information System (INIS)

    Mehedinteanu, S.; Glodeanu, F.; Dobos, I.

    1979-01-01

    With the accumulation of power reactor fuel operating experience, the study of the PCI phenomenon and the development of remedies have become important items in fuel research and development everywhere. The 'power-ramp' failure has drawn attention to the problem of obtaining high reliability from high burn-up fuel rods. Considerable attention has been paid to minimizing the cladding stresses imparted by fuel pellets during the power ramp. The paper describes a new concept of pellet-clad bonding by insertion of UO 2 microspheres in the gap. It is pointed out that the main advantages of this concept are: the low friction coefficient between pellet and clad; the accomodation of cracked pellet expansion by local microyielding of irradiation-embrittled clad; the reduced ridge height by use of undished pellets or other pellet shape; that the fine-sized UO 2 microspheres infiltrate around the pellets thus permitting the use of cracked or chipped pellets and also sintered pellets without the previously required grinding step needed for accurate sizing, etc. (author)

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

    Science.gov (United States)

    Guo, Y.; Fujinoki, H.

    2006-10-01

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

  19. Product ion isotopologue pattern: A tool to improve the reliability of elemental composition elucidations of unknown compounds in complex matrices.

    Science.gov (United States)

    Kaufmann, A; Walker, S; Mol, G

    2016-04-15

    Elucidation of the elemental compositions of unknown compounds (e.g., in metabolomics) generally relies on the availability of accurate masses and isotopic ratios. This study focuses on the information provided by the abundance ratio within a product ion pair (monoisotopic versus the first isotopic peak) when isolating and fragmenting the first isotopic ion (first isotopic mass spectrum) of the precursor. This process relies on the capability of the quadrupole within the Q Orbitrap instrument to isolate a very narrow mass window. Selecting only the first isotopic peak (first isotopic mass spectrum) leads to the observation of a unique product ion pair. The lighter ion within such an isotopologue pair is monoisotopic, while the heavier ion contains a single carbon isotope. The observed abundance ratio is governed by the percentage of carbon atoms lost during the fragmentation and can be described by a hypergeometric distribution. The observed carbon isotopologue abundance ratio (product ion isotopologue pattern) gives reliable information regarding the percentage of carbon atoms lost in the fragmentation process. It therefore facilitates the elucidation of the involved precursor and product ions. Unlike conventional isotopic abundances, the product ion isotopologue pattern is hardly affected by isobaric interferences. Furthermore, the appearance of these pairs greatly aids in cleaning up a 'matrix-contaminated' product ion spectrum. The product ion isotopologue pattern is a valuable tool for structural elucidation. It increases confidence in results and permits structural elucidations for heavier ions. This tool is also very useful in elucidating the elemental composition of product ions. Such information is highly valued in the field of multi-residue analysis, where the accurate mass of product ions is required for the confirmation process. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  20. Reliability demonstration test planning: A three dimensional consideration

    International Nuclear Information System (INIS)

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

    2006-01-01

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

  1. Improving medical diagnosis reliability using Boosted C5.0 decision tree empowered by Particle Swarm Optimization.

    Science.gov (United States)

    Pashaei, Elnaz; Ozen, Mustafa; Aydin, Nizamettin

    2015-08-01

    Improving accuracy of supervised classification algorithms in biomedical applications is one of active area of research. In this study, we improve the performance of Particle Swarm Optimization (PSO) combined with C4.5 decision tree (PSO+C4.5) classifier by applying Boosted C5.0 decision tree as the fitness function. To evaluate the effectiveness of our proposed method, it is implemented on 1 microarray dataset and 5 different medical data sets obtained from UCI machine learning databases. Moreover, the results of PSO + Boosted C5.0 implementation are compared to eight well-known benchmark classification methods (PSO+C4.5, support vector machine under the kernel of Radial Basis Function, Classification And Regression Tree (CART), C4.5 decision tree, C5.0 decision tree, Boosted C5.0 decision tree, Naive Bayes and Weighted K-Nearest neighbor). Repeated five-fold cross-validation method was used to justify the performance of classifiers. Experimental results show that our proposed method not only improve the performance of PSO+C4.5 but also obtains higher classification accuracy compared to the other classification methods.

  2. 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)

  3. 2017 NREL Photovoltaic Reliability Workshop

    Energy Technology Data Exchange (ETDEWEB)

    Kurtz, Sarah [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-08-15

    NREL's Photovoltaic (PV) Reliability Workshop (PVRW) brings together PV reliability experts to share information, leading to the improvement of PV module reliability. Such improvement reduces the cost of solar electricity and promotes investor confidence in the technology -- both critical goals for moving PV technologies deeper into the electricity marketplace.

  4. Monitoring and diagnosis systems to improve nuclear power plant reliability and safety. Proceedings of the specialists` meeting

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-12-31

    The 50 participants, representing 21 Member States (Argentina, Austria, Belgium, Canada, Czech Republic, France, Germany, Hungary, Japan, Netherlands, Norway, Russian Federation, Slovak Republic, Slovenia, Spain, Sweden, Switzerland, Turkey, Ukraine, UK and USA), reviewed the current approaches in Member States in the area of monitoring and diagnosis systems. The Meeting attempted to identify advanced techniques in the field of diagnostics of electrical and mechanical components for safety and operation improvements, reviewed actual practices and experiences related to the application of those systems with special emphasis on real occurrences, exchanged current experiences with diagnostics as a means for predictive maintenance. Refs, figs, tabs.

  5. Monitoring and diagnosis systems to improve nuclear power plant reliability and safety. Proceedings of the specialists' meeting

    International Nuclear Information System (INIS)

    1996-01-01

    The 50 participants, representing 21 Member States (Argentina, Austria, Belgium, Canada, Czech Republic, France, Germany, Hungary, Japan, Netherlands, Norway, Russian Federation, Slovak Republic, Slovenia, Spain, Sweden, Switzerland, Turkey, Ukraine, UK and USA), reviewed the current approaches in Member States in the area of monitoring and diagnosis systems. The Meeting attempted to identify advanced techniques in the field of diagnostics of electrical and mechanical components for safety and operation improvements, reviewed actual practices and experiences related to the application of those systems with special emphasis on real occurrences, exchanged current experiences with diagnostics as a means for predictive maintenance. Refs, figs, tabs

  6. Journey Toward High Reliability: A Comprehensive Safety Program to Improve Quality of Care and Safety Culture in a Large, Multisite Radiation Oncology Department.

    Science.gov (United States)

    Woodhouse, Kristina Demas; Volz, Edna; Maity, Amit; Gabriel, Peter E; Solberg, Timothy D; Bergendahl, Howard W; Hahn, Stephen M

    2016-05-01

    High-reliability organizations (HROs) focus on continuous identification and improvement of safety issues. We sought to advance a large, multisite radiation oncology department toward high reliability through the implementation of a comprehensive safety culture (SC) program at the University of Pennsylvania Department of Radiation Oncology. In 2011, with guidance from safety literature and experts in HROs, we designed an SC framework to reduce radiation errors. All state-reported medical events (SRMEs) from 2009 to 2016 were retrospectively reviewed and plotted on a control chart. Changes in SC grade were assessed using the Agency for Healthcare Research and Quality Hospital Survey. Outcomes measured included the number of radiation treatment fractions and days between SRMEs, as well as SC grade. Multifaceted safety initiatives were implemented at our main academic center and across all network sites. Postintervention results demonstrate increased staff fundamental safety knowledge, enhanced peer review with an electronic system, and special cause variation of SRMEs on control chart analysis. From 2009 to 2016, the number of days and fractions between SRMEs significantly increased, from a mean of 174 to 541 days (P safety framework. Our multifaceted initiatives, focusing on culture and system changes, can be successfully implemented in a large academic radiation oncology department to yield measurable improvements in SC and outcomes. Copyright © 2016 by American Society of Clinical Oncology.

  7. An improved behavioural assay demonstrates that ultrasound vocalizations constitute a reliable indicator of chronic cancer pain and neuropathic pain

    Directory of Open Access Journals (Sweden)

    Selvaraj Deepitha

    2010-03-01

    Full Text Available Abstract Background On-going pain is one of the most debilitating symptoms associated with a variety of chronic pain disorders. An understanding of mechanisms underlying on-going pain, i.e. stimulus-independent pain has been hampered so far by a lack of behavioural parameters which enable studying it in experimental animals. Ultrasound vocalizations (USVs have been proposed to correlate with pain evoked by an acute activation of nociceptors. However, literature on the utility of USVs as an indicator of chronic pain is very controversial. A majority of these inconsistencies arise from parameters confounding behavioural experiments, which include novelty, fear and stress due to restrain, amongst others. Results We have developed an improved assay which overcomes these confounding factors and enables studying USVs in freely moving mice repetitively over several weeks. Using this improved assay, we report here that USVs increase significantly in mice with bone metastases-induced cancer pain or neuropathic pain for several weeks, in comparison to sham-treated mice. Importantly, analgesic drugs which are known to alleviate tumour pain or neuropathic pain in human patients significantly reduce USVs as well as mechanical allodynia in corresponding mouse models. Conclusions We show that studying USVs and mechanical allodynia in the same cohort of mice enables comparing the temporal progression of on-going pain (i.e. stimulus-independent pain and stimulus-evoked pain in these clinically highly-relevant forms of chronic pain.

  8. Fatigue study and improve reliability of cantilever type micro piezoelectric energy harvesters reinforced with flexible adhesive conductive tape

    Science.gov (United States)

    Lin, T. K.; Hsieh, Y. C.; Chen, C. T.; Chen, J. J.; Wu, W. J.

    2016-04-01

    Cantilever type piezoelectric energy harvester (PEH) is widely adopted in the design of vibration energy harvesters because of simple, effective and easy to fabricate. When the PEH is working under excitation of continuous vibration sources, like mounting on motors, reliability and durability is a major concern. The failure mode and fatigue issues will be important design considerations in field applications. Since the largest strain of a cantilever structure is located in the clamping position of fixed end, the location is therefore the weakest point of the structure and the hot zone of mechanical cracks. The failure mode due to fatigue under long time excitation of vibration sources is typically continuously developing small cracks on the piezoelectric PZT films till tearing the surface electrodes and caused open circuit to the output circuitry. Therefore, extending the lifetime with minimize the surface electrodes cracking becomes a key point for field applications. Previously, we focused on the output performance of PEH. At PowerMEMS 2014 [1], we presented a high performance PEH based on PZT thin films fabricated with a homemade PZT deposition equipment on stainless steel substrates. We confirmed that the stainless steel based PEH can generate better output power than silicon based devices under the same vibration excitation levels, and also the stainless based PEH can have longer lifetime when excited at higher vibration levels due to better mechanical strength. In this study, we tried to further reinforce the PEH with a conductive adhesive tape sticking on the surface electrode near the clamping position. We investigated the change of failure mode and mechanical behaviors, including the frequency bandwidth and non-linearity of the piezoelectric energy harvester. The PEH devices was mounted on a shaker for long time testing with vibration frequency set around 120Hz at 0.5g, 0.6g, and 0.7g acceleration vibration levels. The electrodes of the PEH device were

  9. Effort to grapple with improvement of security and reliability of nuclear power plant. Actions of the Japan Atomic Power Company

    International Nuclear Information System (INIS)

    Ishiguma, Kazuo

    2012-01-01

    Following the Great Tohoku Earthquake in 2011, Tokai No.2 reactor was shut down automatically. Three of emergency diesel generators worked automatically at loss-of-offsite-power and began to work the cooling system of reactor. The reactor could be kept stable and safe in cold state by management of power from the gas turbine electric generator and power source car. Actions of Japan Atomic Power Company (JAPC) for cold shutdown and Tsunami were stated. Inspection results after the earthquake and testimony of staff was described. Countermeasure of improvement of safety of nuclear power station is explained by ensuring of power source and water supply, crisis management system, countermeasure of accident, ensuring, and training of workers, and action for better understanding of reliance. (S.Y.)

  10. 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.

  11. Evolution of Machine Reliability and Life and Economics of Operational Use

    Directory of Open Access Journals (Sweden)

    Młynarski Stanisław

    2016-12-01

    Full Text Available The article presents new assumptions for reliability and life of machines, resulting from the development of technology. The innovative approach to reliability and life design as well as warranty duration planning is presented on an example of vehicle reliability characteristics. A new algorithm is proposed for the replacement of repairable objects costs by the price of life and reliability of new unrepairable ones. For the planning of the life of innovative machines, an effective method of technical progress rate determination is proposed. In conclusion, necessary modifications of machine and vehicle use systems, resulting from technology evolution and technical progress, are indicated. Finally, recommendations and directions of indispensable research in engineering and management of technical means of production are formulated.

  12. ADVANCED MONITORING TO IMPROVE COMBUSTION TURBINE/COMBINED CYCLE CT/(CC) RELIABILITY, AVAILABILITY AND MAINTAINABILITY (RAM)

    Energy Technology Data Exchange (ETDEWEB)

    Leonard Angello

    2003-09-30

    Power generators are concerned with the maintenance costs associated with the advanced turbines that they are purchasing. Since these machines do not have fully established operation and maintenance (O&M) track records, power generators face financial risk due to uncertain future maintenance costs. This risk is of particular concern, as the electricity industry transitions to a competitive business environment in which unexpected O&M costs cannot be passed through to consumers. These concerns have accelerated the need for intelligent software-based diagnostic systems that can monitor the health of a combustion turbine in real time and provide valuable information on the machine's performance to its owner/operators. Such systems would interpret sensor and instrument outputs, correlate them to the machine's condition, provide interpretative analyses, forward projections of servicing intervals, estimate remaining component life, and identify faults. EPRI, Impact Technologies, Boyce Engineering, and Progress Energy have teamed to develop a suite of intelligent software tools integrated with a diagnostic monitoring platform that will, in real time, interpret data to assess the ''total health'' of combustion turbines. The Combustion Turbine Health Management System (CTHM) will consist of a series of dynamic link library (DLL) programs residing on a diagnostic monitoring platform that accepts turbine health data from existing monitoring instrumentation. The CTHM system will be a significant improvement over currently available techniques for turbine monitoring and diagnostics. CTHM will interpret sensor and instrument outputs, correlate them to a machine's condition, provide interpretative analyses, project servicing intervals, and estimate remaining component life. In addition, it will enable real-time anomaly detection and diagnostics of performance and mechanical faults, enabling power producers to more accurately predict critical

  13. Can we improve accuracy and reliability of MRI interpretation in children with optic pathway glioma? Proposal for a reproducible imaging classification

    Energy Technology Data Exchange (ETDEWEB)

    Lambron, Julien; Frampas, Eric; Toulgoat, Frederique [University Hospital, Department of Radiology, Nantes (France); Rakotonjanahary, Josue [University Hospital, Department of Pediatric Oncology, Angers (France); University Paris Diderot, INSERM CIE5 Robert Debre Hospital, Assistance Publique-Hopitaux de Paris (AP-HP), Paris (France); Loisel, Didier [University Hospital, Department of Radiology, Angers (France); Carli, Emilie de; Rialland, Xavier [University Hospital, Department of Pediatric Oncology, Angers (France); Delion, Matthieu [University Hospital, Department of Neurosurgery, Angers (France)

    2016-02-15

    Magnetic resonance (MR) images from children with optic pathway glioma (OPG) are complex. We initiated this study to evaluate the accuracy of MR imaging (MRI) interpretation and to propose a simple and reproducible imaging classification for MRI. We randomly selected 140 MRIs from among 510 MRIs performed on 104 children diagnosed with OPG in France from 1990 to 2004. These images were reviewed independently by three radiologists (F.T., 15 years of experience in neuroradiology; D.L., 25 years of experience in pediatric radiology; and J.L., 3 years of experience in radiology) using a classification derived from the Dodge and modified Dodge classifications. Intra- and interobserver reliabilities were assessed using the Bland-Altman method and the kappa coefficient. These reviews allowed the definition of reliable criteria for MRI interpretation. The reviews showed intraobserver variability and large discrepancies among the three radiologists (kappa coefficient varying from 0.11 to 1). These variabilities were too large for the interpretation to be considered reproducible over time or among observers. A consensual analysis, taking into account all observed variabilities, allowed the development of a definitive interpretation protocol. Using this revised protocol, we observed consistent intra- and interobserver results (kappa coefficient varying from 0.56 to 1). The mean interobserver difference for the solid portion of the tumor with contrast enhancement was 0.8 cm{sup 3} (limits of agreement = -16 to 17). We propose simple and precise rules for improving the accuracy and reliability of MRI interpretation for children with OPG. Further studies will be necessary to investigate the possible prognostic value of this approach. (orig.)

  14. Reliability Engineering

    CERN Document Server

    Lazzaroni, Massimo

    2012-01-01

    This book gives a practical guide for designers and users in Information and Communication Technology context. In particular, in the first Section, the definition of the fundamental terms according to the international standards are given. Then, some theoretical concepts and reliability models are presented in Chapters 2 and 3: the aim is to evaluate performance for components and systems and reliability growth. Chapter 4, by introducing the laboratory tests, puts in evidence the reliability concept from the experimental point of view. In ICT context, the failure rate for a given system can be

  15. Reliability training

    Science.gov (United States)

    Lalli, Vincent R. (Editor); Malec, Henry A. (Editor); Dillard, Richard B.; Wong, Kam L.; Barber, Frank J.; Barina, Frank J.

    1992-01-01

    Discussed here 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. A review of reliability for the years 1940 to 2000 is given. Next, a review of mathematics is given as well as a description of what elements contribute to product failures. Basic reliability theory and the disciplines that allow us to control and eliminate failures are elucidated.

  16. Improving the Reliability of Optimised Link State Routing in a Smart Grid Neighbour Area Network based Wireless Mesh Network Using Multiple Metrics

    Directory of Open Access Journals (Sweden)

    Yakubu Tsado

    2017-02-01

    Full Text Available Reliable communication is the backbone of advanced metering infrastructure (AMI. Within the AMI, the neighbourhood area network (NAN transports a multitude of traffic, each with unique requirements. In order to deliver an acceptable level of reliability and latency, the underlying network, such as the wireless mesh network(WMN, must provide or guarantee the quality-of-service (QoS level required by the respective application traffic. Existing WMN routing protocols, such as optimised link state routing (OLSR, typically utilise a single metric and do not consider the requirements of individual traffic; hence, packets are delivered on a best-effort basis. This paper presents a QoS-aware WMN routing technique that employs multiple metrics in OLSR optimal path selection for AMI applications. The problems arising from this approach are non deterministic polynomial time (NP-complete in nature, which were solved through the combined use of the analytical hierarchy process (AHP algorithm and pruning techniques. For smart meters transmitting Internet Protocol (IP packets of varying sizes at different intervals, the proposed technique considers the constraints of NAN and the applications’ traffic characteristics. The technique was developed by combining multiple OLSR path selection metrics with the AHP algorithminns-2. Compared with the conventional link metric in OLSR, the results show improvements of about 23% and 45% in latency and Packet Delivery Ratio (PDR, respectively, in a 25-node grid NAN.

  17. Development of improved processing and evaluation methods for high reliability structural ceramics for advanced heat engine applications Phase II. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Pujari, V.J.; Tracey, D.M.; Foley, M.R. [and others

    1996-02-01

    The research program had as goals the development and demonstration of significant improvements in processing methods, process controls, and nondestructive evaluation (NDE) which can be commercially implemented to produce high reliability silicon nitride components for advanced heat engine applications at temperatures to 1370{degrees}C. In Phase I of the program a process was developed that resulted in a silicon nitride - 4 w% yttria HIP`ed material (NCX 5102) that displayed unprecedented strength and reliability. An average tensile strength of 1 GPa and a strength distribution following a 3-parameter Weibull distribution were demonstrated by testing several hundred buttonhead tensile specimens. The Phase II program focused on the development of methodology for colloidal consolidation producing green microstructure which minimizes downstream process problems such as drying, shrinkage, cracking, and part distortion during densification. Furthermore, the program focused on the extension of the process to gas pressure sinterable (GPS) compositions. Excellent results were obtained for the HIP composition processed for minimal density gradients, both with respect to room-temperature strength and high-temperature creep resistance. Complex component fabricability of this material was demonstrated by producing engine-vane prototypes. Strength data for the GPS material (NCX-5400) suggest that it ranks very high relative to other silicon nitride materials in terms of tensile/flexure strength ratio, a measure of volume quality. This high quality was derived from the closed-loop colloidal process employed in the program.

  18. Teflon/SiO2 Bilayer Passivation for Improving the Electrical Reliability of Oxide TFTs Fabricated Using a New Two-Photomask Self-Alignment Process

    Science.gov (United States)

    Fan, Ching-Lin; Shang, Ming-Chi; Li, Bo-Jyun; Lin, Yu-Zuo; Wang, Shea-Jue; Lee, Win-Der; Hung, Bohr-Ran

    2015-01-01

    This study proposes a two-photomask process for fabricating amorphous indium–gallium–zinc oxide (a-IGZO) thin-film transistors (TFTs) that exhibit a self-aligned structure. The fabricated TFTs, which lack etching-stop (ES) layers, have undamaged a-IGZO active layers that facilitate superior performance. In addition, we demonstrate a bilayer passivation method that uses a polytetrafluoroethylene (Teflon) and SiO2 combination layer for improving the electrical reliability of the fabricated TFTs. Teflon was deposited as a buffer layer through thermal evaporation. The Teflon layer exhibited favorable compatibility with the underlying IGZO channel layer and effectively protected the a-IGZO TFTs from plasma damage during SiO2 deposition, resulting in a negligible initial performance drop in the a-IGZO TFTs. Compared with passivation-free a-IGZO TFTs, passivated TFTs exhibited superior stability even after 168 h of aging under ambient air at 95% relative humidity. PMID:28788026

  19. Teflon/SiO₂ Bilayer Passivation for Improving the Electrical Reliability of Oxide TFTs Fabricated Using a New Two-Photomask Self-Alignment Process.

    Science.gov (United States)

    Fan, Ching-Lin; Shang, Ming-Chi; Li, Bo-Jyun; Lin, Yu-Zuo; Wang, Shea-Jue; Lee, Win-Der; Hung, Bohr-Ran

    2015-04-13

    This study proposes a two-photomask process for fabricating amorphous indium-gallium-zinc oxide (a-IGZO) thin-film transistors (TFTs) that exhibit a self-aligned structure. The fabricated TFTs, which lack etching-stop (ES) layers, have undamaged a-IGZO active layers that facilitate superior performance. In addition, we demonstrate a bilayer passivation method that uses a polytetrafluoroethylene (Teflon) and SiO₂ combination layer for improving the electrical reliability of the fabricated TFTs. Teflon was deposited as a buffer layer through thermal evaporation. The Teflon layer exhibited favorable compatibility with the underlying IGZO channel layer and effectively protected the a-IGZO TFTs from plasma damage during SiO₂ deposition, resulting in a negligible initial performance drop in the a-IGZO TFTs. Compared with passivation-free a-IGZO TFTs, passivated TFTs exhibited superior stability even after 168 h of aging under ambient air at 95% relative humidity.

  20. Teflon/SiO2 Bilayer Passivation for Improving the Electrical Reliability of Oxide TFTs Fabricated Using a New Two-Photomask Self-Alignment Process

    Directory of Open Access Journals (Sweden)

    Ching-Lin Fan

    2015-04-01

    Full Text Available This study proposes a two-photomask process for fabricating amorphous indium–gallium–zinc oxide (a-IGZO thin-film transistors (TFTs that exhibit a self-aligned structure. The fabricated TFTs, which lack etching-stop (ES layers, have undamaged a-IGZO active layers that facilitate superior performance. In addition, we demonstrate a bilayer passivation method that uses a polytetrafluoroethylene (Teflon and SiO2 combination layer for improving the electrical reliability of the fabricated TFTs. Teflon was deposited as a buffer layer through thermal evaporation. The Teflon layer exhibited favorable compatibility with the underlying IGZO channel layer and effectively protected the a-IGZO TFTs from plasma damage during SiO2 deposition, resulting in a negligible initial performance drop in the a-IGZO TFTs. Compared with passivation-free a-IGZO TFTs, passivated TFTs exhibited superior stability even after 168 h of aging under ambient air at 95% relative humidity.

  1. 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.)

  2. Design reliability engineering

    International Nuclear Information System (INIS)

    Buden, D.; Hunt, R.N.M.

    1989-01-01

    Improved design techniques are needed to achieve high reliability at minimum cost. This is especially true of space systems where lifetimes of many years without maintenance are needed and severe mass limitations exist. Reliability must be designed into these systems from the start. Techniques are now being explored to structure a formal design process that will be more complete and less expensive. The intent is to integrate the best features of design, reliability analysis, and expert systems to design highly reliable systems to meet stressing needs. Taken into account are the large uncertainties that exist in materials, design models, and fabrication techniques. Expert systems are a convenient method to integrate into the design process a complete definition of all elements that should be considered and an opportunity to integrate the design process with reliability, safety, test engineering, maintenance and operator training. 1 fig

  3. Reliability Validation and Improvement Framework

    Science.gov (United States)

    2012-11-01

    systems life cycle ( ISO /IEC 15288) and for the software life cycle ( ISO /IEC 12207 )[ ISO /IEC 2008a, 2008b] • revision of recommended practice for...Standardization/International Electrotechnical Commission. ISO /IEC 12207 : 2008 Systems and Software Engineering–System Life Cycle Processes. 2008. Available...the Capability Maturity Model Integration® (CMMI®), MIL-STD-882, SAE ARP4754, SAE ARP4761, DO-178B, DO-254, UK 00-56, IEC/ ISO 15026, IEC 61508, and

  4. Reliability data book

    International Nuclear Information System (INIS)

    Bento, J.P.; Boerje, S.; Ericsson, G.; Hasler, A.; Lyden, C.O.; Wallin, L.; Poern, K.; Aakerlund, O.

    1985-01-01

    The main objective for the report is to improve failure data for reliability calculations as parts of safety analyses for Swedish nuclear power plants. The work is based primarily on evaluations of failure reports as well as information provided by the operation and maintenance staff of each plant. In the report are presented charts of reliability data for: pumps, valves, control rods/rod drives, electrical components, and instruments. (L.E.)

  5. Human reliability

    International Nuclear Information System (INIS)

    Bubb, H.

    1992-01-01

    This book resulted from the activity of Task Force 4.2 - 'Human Reliability'. This group was established on February 27th, 1986, at the plenary meeting of the Technical Reliability Committee of VDI, within the framework of the joint committee of VDI on industrial systems technology - GIS. It is composed of representatives of industry, representatives of research institutes, of technical control boards and universities, whose job it is to study how man fits into the technical side of the world of work and to optimize this interaction. In a total of 17 sessions, information from the part of ergonomy dealing with human reliability in using technical systems at work was exchanged, and different methods for its evaluation were examined and analyzed. The outcome of this work was systematized and compiled in this book. (orig.) [de

  6. Microelectronics Reliability

    Science.gov (United States)

    2017-01-17

    inverters  connected in a chain. ................................................. 5  Figure 3  Typical graph showing frequency versus square root of...developing an experimental  reliability estimating methodology that could both illuminate the  lifetime  reliability of advanced devices,  circuits and...or  FIT of the device. In other words an accurate estimate of the device  lifetime  was found and thus the  reliability  that  can  be  conveniently

  7. Reliability improvement of a-Si:H thin film transistors on plastic substrate with saturation in deep state after multiple bending cycles

    International Nuclear Information System (INIS)

    Lee, M.H.; Chen, P.-G.; Hsu, C.-C.

    2013-01-01

    For flexible electronic applications, the disordered bonds of a-Si:H may generate a redistribution of trapped states with mechanical strain. During mechanical strain, the deep states are redistributed in a Gaussian distribution and are dissimilar to ordinary acceptor-like deep states, which manifest with exponential distributions. The redistributed deep states may saturate with multiple mechanical bending cycles, and it would improve the reliability with drain current stress of a-Si:H TFTs (thin film transistors) on flexible substrates. We conclude that it is possible to produce low-cost and highly uniform active-matrix organic light emitting diodes systems for use in flexible display applications using a-Si:H TFTs array backplanes. - Highlights: • The stress stability of a-Si:H TFTs (thin-film transistors) was improved after bending cycles. • The saturated deep states after bending were confirmed. • The simulation and extracted gap state density of a-Si:H TFT under strain was calculated

  8. 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)

  9. Health Complaints Associated with Poor Rental Housing Conditions in Arkansas: The Only State without a Landlord's Implied Warranty of Habitability.

    Science.gov (United States)

    Bachelder, Ashley E; Stewart, M Kate; Felix, Holly C; Sealy, Neil

    2016-01-01

    Arkansas is the only U.S. state that does not have a landlord's implied warranty of habitability, meaning tenants have a requirement for maintaining their rental properties at certain habitability standards, but landlords are not legally required to contribute to those minimum health and safety standards. This project assessed the possibility that this lack of landlord responsibility affects tenants' perceived health. Using surveys and interviews, we collected self-reported data on the prevalence and description of problems faced by renters who needed household repairs from their landlords. Of almost 1,000 renters, one-third of them had experienced a problem with their landlord making needed repairs; and one-quarter of those had a health issue they attributed to their housing conditions. Common issues included problems with plumbing, heating, or cooling systems, and pest or rodent control. Reported health problems included elevated stress levels, breathing problems, headaches, high blood pressure, and bites or infections. Hispanic respondents and those with less than a high school education were both significantly more likely to report problems with their landlords not making repairs as requested. These data suggest that the lack of landlord requirements may negatively impact the condition of rental properties and, therefore, may negatively impact the health of Arkansas renters.

  10. Implementation of Contract Hybrid Concept in Multi Services Products (Aplication of the Warranty Bank Products/Kafalah in Syariah Banks

    Directory of Open Access Journals (Sweden)

    Muhammad Firmansyah

    2016-08-01

    Full Text Available Product of multi services in sharia banks presented in order to meet the needs of society as well as the development of the era transactions that course in accordance with Islamic principles, then the ownership  in  the syariah products  including  multi  product  in  Islamic banking  services  using  the concept of multi akad therein. This is done so that innovation in Islamic banking products had been developed so that it can be chosen by the public in conducting business transactions. Likewise, the multi-service bank guarantee products in Islamic banking, is a multi product contract, where there is more than one contract. Bank guarantees in Islamic banking is generally called kafalah product because this product is Kafalah main contract, followed by Ijarah contract, wadiah, and qardh. This paper  examines  the  concept  of  multi-contract/contract executed  hybrid  shariah  banking  at  bank product warranty/kafalah

  11. Redefining reliability

    International Nuclear Information System (INIS)

    Paulson, S.L.

    1995-01-01

    Want to buy some reliability? The question would have been unthinkable in some markets served by the natural gas business even a few years ago, but in the new gas marketplace, industrial, commercial and even some residential customers have the opportunity to choose from among an array of options about the kind of natural gas service they need--and are willing to pay for. The complexities of this brave new world of restructuring and competition have sent the industry scrambling to find ways to educate and inform its customers about the increased responsibility they will have in determining the level of gas reliability they choose. This article discusses the new options and the new responsibilities of customers, the needed for continuous education, and MidAmerican Energy Company's experiment in direct marketing of natural gas

  12. A Single-Phase Current Source Solar Inverter with Constant Instantaneous Power, Improved Reliability, and Reduced-Size DC-Link Filter

    Science.gov (United States)

    Bush, Craig R.

    This dissertation presents a novel current source converter topology that is primarily intended for single-phase photovoltaic (PV) applications. In comparison with the existing PV inverter technology, the salient features of the proposed topology are: a) the low frequency (double of line frequency) ripple that is common to single-phase inverters is greatly reduced; b) the absence of low frequency ripple enables significantly reduced size pass components to achieve necessary DC-link stiffness and c) improved maximum power point tracking (MPPT) performance is readily achieved due to the tightened current ripple even with reduced-size passive components. The proposed topology does not utilize any electrolytic capacitors. Instead an inductor is used as the DC-link filter and reliable AC film capacitors are utilized for the filter and auxiliary capacitor. The proposed topology has a life expectancy on par with PV panels. The proposed modulation technique can be used for any current source inverter where an unbalanced three-phase operation is desires such as active filters and power controllers. The proposed topology is ready for the next phase of microgrid and power system controllers in that it accepts reactive power commands. This work presents the proposed topology and its working principle supported by with numerical verifications and hardware results. Conclusions and future work are also presented.

  13. Maui Smart Grid Demonstration Project Managing Distribution System Resources for Improved Service Quality and Reliability, Transmission Congestion Relief, and Grid Support Functions

    Energy Technology Data Exchange (ETDEWEB)

    none,

    2014-09-30

    The Maui Smart Grid Project (MSGP) is under the leadership of the Hawaii Natural Energy Institute (HNEI) of the University of Hawaii at Manoa. The project team includes Maui Electric Company, Ltd. (MECO), Hawaiian Electric Company, Inc. (HECO), Sentech (a division of SRA International, Inc.), Silver Spring Networks (SSN), Alstom Grid, Maui Economic Development Board (MEDB), University of Hawaii-Maui College (UHMC), and the County of Maui. MSGP was supported by the U.S. Department of Energy (DOE) under Cooperative Agreement Number DE-FC26-08NT02871, with approximately 50% co-funding supplied by MECO. The project was designed to develop and demonstrate an integrated monitoring, communications, database, applications, and decision support solution that aggregates renewable energy (RE), other distributed generation (DG), energy storage, and demand response technologies in a distribution system to achieve both distribution and transmission-level benefits. The application of these new technologies and procedures will increase MECO’s visibility into system conditions, with the expected benefits of enabling more renewable energy resources to be integrated into the grid, improving service quality, increasing overall reliability of the power system, and ultimately reducing costs to both MECO and its customers.

  14. Nuclear performance and reliability

    International Nuclear Information System (INIS)

    Rothwell, G.

    1993-01-01

    If fewer forced outages are a sign of improved safety, nuclear power plants have become safer and more productive. There has been a significant improvement in nuclear power plant performance, due largely to a decline in the forced outage rate and a dramatic drop in the average number of forced outages per fuel cycle. If fewer forced outages are a sign of improved safety, nuclear power plants have become safer and more productive over time. To encourage further increases in performance, regulatory incentive schemes should reward reactor operators for improved reliability and safety, as well as for improved performance

  15. Reliability and improvement of RODOS results for a BWR plant; Erhoehung der Zuverlaessigkeit der RODOS-Ergebnisse fuer eine SWR-Anlage

    Energy Technology Data Exchange (ETDEWEB)

    Loeffler, H.; Cester, F.; Sonnenkalb, M.; Klein-Hessling, W.; Voggenberger, T.

    2009-06-15

    Decision support systems such as RODOS aim to support the responsible authorities by providing estimates for the possible radiological consequences in case of an event in a nuclear plant. The prognosis of quantity, composition and time of occurrence of a release from the plant (''source term'') in the so-called pre-release phase is one of the foundations with high relevance for this purpose. Within previous projects source term prognosis tools have been developed and applied exemplarily for a PWR. At the end of 2005 GRS has finalized a PSA level 2 for a plant of the SWR-69 type. On this basis improved versions of the source term prognosis tools QPRO (probabilistic) and ASTRID (deterministic) have been created for a BWR and tested in an emergency exercise in a BWR. The further development of QPRO has been related in particular to the structure of the probabilistic network and the precalculated source terms. The activities for the adaptation of ASTRID focus on the creation of the dataset for the BWR coolant loop and the containment. In the emergency exercise the manageability of QPRO but also of ASTRID has been proven. Further, the first phases of the accident progression have been well identified. However, the exercise scenario developed into a very unlikely sequence with partial core melt, and the reactor building ventilation was shut off just at a critical moment. Therefore the source term prognoses deviate from the exercise scenario. Starting from these experiences with the development and application of QPRO and ASTRID recommendations are given for the further improvement of the reliability of the source term prognosis for RODOS. In general it can be stated that the development status of QPRO and ASTRID is definitely advanced compared to the presently still prevailing source term prognosis methods. Therefore it is recommended to develop plant specific versions of these codes and to apply them.

  16. Assessing the validity and reliability of self-report data on contraception use in the MObile Technology for Improved Family Planning (MOTIF) randomised controlled trial.

    Science.gov (United States)

    Smith, Chris; Edwards, Phil; Free, Caroline

    2018-03-15

    A variety of different approaches to measuring contraceptive use have been used or proposed, either to assess current use or adherence over time, using subjective or objective measures. This paper reports an overview of approaches to measuring adherence to the oral contraceptive, intra-uterine device, sub-dermal implant, and injectable and describes how we assessed contraception use in the MObile Technology for Improved Family Planning (MOTIF) trial in Cambodia. We summarise and discuss advantages and disadvantages of different subjective and objective approaches to measuring adherence to the oral contraceptive, intra-uterine device, sub-dermal implant, and injectable such as self-reports, clinic records, electronic monitoring devices, clinical examination and biomarkers. For the MOTIF trial, we did not consider it feasible to measure objective contraception use as many participants lived a long distance from the clinic and we were concerned whether it was appropriate to ask women to return to clinic for a physical examination simply to verify self-report information already provided. We aimed to assess the validity of the four-month data with 50 participants, calculating the sensitivity and specificity of self-reported data compared with objective measurement. For the 46 valid measurements obtained, the sensitivity and specificity was 100% for self-reported contraception use compared to objective measurement but this study had some limitations. To assess reliability of self-report data we compared calendar data collected on effective contraception use at months 1-4 post-abortion, collected separately at four and 12 months. Agreement ranged from 80 to 84% with a kappa statistic ranging from 0·59 to 0·67 indicating fair to good agreement. There is no perfect method of assessing contraception use and researchers designing future studies should give consideration of what to measure, for example current use or detailed patterns of use over time, and remain mindful

  17. Development of improved processing and evaluation methods for high reliability structural ceramics for advanced heat engine applications, Phase 1. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Pujari, V.K.; Tracey, D.M.; Foley, M.R.; Paille, N.I.; Pelletier, P.J.; Sales, L.C.; Wilkens, C.A.; Yeckley, R.L. [Norton Co., Northboro, MA (United States)

    1993-08-01

    The program goals were to develop and demonstrate significant improvements in processing methods, process controls and non-destructive evaluation (NDE) which can be commercially implemented to produce high reliability silicon nitride components for advanced heat engine applications at temperatures to 1,370{degrees}C. The program focused on a Si{sub 3}N{sub 4}-4% Y{sub 2}O{sub 3} high temperature ceramic composition and hot-isostatic-pressing as the method of densification. Stage I had as major objectives: (1) comparing injection molding and colloidal consolidation process routes, and selecting one route for subsequent optimization, (2) comparing the performance of water milled and alcohol milled powder and selecting one on the basis of performance data, and (3) adapting several NDE methods to the needs of ceramic processing. The NDE methods considered were microfocus X-ray radiography, computed tomography, ultrasonics, NMR imaging, NMR spectroscopy, fluorescent liquid dye penetrant and X-ray diffraction residual stress analysis. The colloidal consolidation process route was selected and approved as the forming technique for the remainder of the program. The material produced by the final Stage II optimized process has been given the designation NCX 5102 silicon nitride. According to plan, a large number of specimens were produced and tested during Stage III to establish a statistically robust room temperature tensile strength database for this material. Highlights of the Stage III process demonstration and resultant database are included in the main text of the report, along with a synopsis of the NCX-5102 aqueous based colloidal process. The R and D accomplishments for Stage I are discussed in Appendices 1--4, while the tensile strength-fractography database for the Stage III NCX-5102 process demonstration is provided in Appendix 5. 4 refs., 108 figs., 23 tabs.

  18. Mining a database of single amplified genomes from Red Sea brine pool extremophiles-improving reliability of gene function prediction using a profile and pattern matching algorithm (PPMA).

    KAUST Repository

    Grö tzinger, Stefan W.; Alam, Intikhab; Ba Alawi, Wail; Bajic, Vladimir B.; Stingl, Ulrich; Eppinger, Jö rg

    2014-01-01

    Reliable functional annotation of genomic data is the key-step in the discovery of novel enzymes. Intrinsic sequencing data quality problems of single amplified genomes (SAGs) and poor homology of novel extremophile's genomes pose significant

  19. Progress in evaluation and improvement in nondestructive examination reliability for inservice inspection of Light Water Reactors (LWRs) and characterize fabrication flaws in reactor pressure vessels

    International Nuclear Information System (INIS)

    Doctor, S.R.; Bowey, R.E.; Good, M.S.; Friley, J.R.; Kurtz, R.J.; Simonen, F.A.; Taylor, T.T.; Heasler, P.G.; Andersen, E.S.; Diaz, A.A.; Greenwood, M.S.; Hockey, R.L.; Schuster, G.J.; Spanner, J.C.; Vo, T.V.

    1991-10-01

    This paper is a review of the work conducted under two programs. One (NDE Reliability Program) is a multi-year program addressing the reliability of nondestructive evaluation (NDE) for the inservice inspection (ISI) of light water reactor components. This program examines the reliability of current NDE, the effectiveness of evolving technologies, and provides assessments and recommendations to ensure that the NDE is applied at the right time, in the right place with sufficient effectiveness that defects of importance to structural integrity will be reliably detected and accurately characterized. The second program (Characterizing Fabrication Flaws in Reactor Pressure Vessels) is assembling a data base to quantify the distribution of fabrication flaws that exist in US nuclear reactor pressure vessels with respect to density, size, type, and location. These programs will be discussed as two separate sections in this report. 4 refs., 7 figs

  20. Definição do prazo de garantia de um produto otimizado experimentalmente Definition of the warranty period of an experimentally optimized product

    Directory of Open Access Journals (Sweden)

    Morgana Pizzolato

    2005-08-01

    Full Text Available Este artigo documenta os resultados da aplicação de um método para otimização de aspectos da qualidade e vida útil para posterior definição do prazo de garantia de produtos que não falham, mas degradam até uma condição considerada aceitável. O método de otimização é composto pelas seguintes etapas: i caracterização do problema; ii planejamento e execução dos experimentos; iii modelagem das variáveis de resposta; iv otimização; e v modelagem da vida útil e definição do prazo de garantia. As etapas metodológicas contemplam o uso de QFD (Desdobramento da Função Qualidade, de Projeto de Experimentos, modelos de regressão de ensaios acelerados e modelos de degradação. Para a otimização e determinação do prazo de garantia, é apresentado um procedimento que utiliza uma seqüência de passos em que ferramentas estatísticas, como análise de regressão e modelagem de dados de degradação, são empregadas. Somado a isso, são utilizados procedimentos de avaliação sensorial para avaliar os níveis de degradação das amostras do produto. O método é aplicado em um produto utilizado na criação de animais.This paper discusses the results of the application of a method to optimize the quality characteristics and service life of products that degrade rather than fail in order to determine the warranty period of such products. The optimization method consists of the following steps: i characterization of the problem; ii planning and execution of experiments; iii modeling of response variables; iv optimization; and v modeling of the product's service life and definition of its warranty period. The method involves the joint use of QFD (Quality Function Deployment, Experimental Design, and modeling of accelerated degradation tests through regression analysis. A new procedure is presented to determine and optimize the warranty period of products subject to degradation, based on the sensorial analysis of sample products

  1. Improvement of the electromagnetic situation in networks of operational current at nuclear power plant for the purpose of ensuring reliability of monitoring systems, control, RPA and communications, realized on the basis of digital equipment

    International Nuclear Information System (INIS)

    Fomenko, O.V.; Moloshnaya, E.S.; Ul'yanova, Yu.E.

    2014-01-01

    The authors propose the technique of designing a portable grounding contour for protection and control systems, relay protection and automation (RPA) systems made on the basis of digital equipment in networks of an operational direct current to increase the reliability of their functioning under the conditions of influence of strong hindrances and improvement of an electromagnetic environment [ru

  2. 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.

  3. 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.

  4. Improving the Reliability and Modal Stability of High Power 870 nm AlGaAs CSP Laser Diodes for Applications to Free Space Communication Systems

    Science.gov (United States)

    Connolly, J. C.; Alphonse, G. A.; Carlin, D. B.; Ettenberg, M.

    1991-01-01

    The operating characteristics (power-current, beam divergence, etc.) and reliability assessment of high-power CSP lasers is discussed. The emission wavelength of these lasers was optimized at 860 to 880 nm. The operational characteristics of a new laser, the inverse channel substrate planar (ICSP) laser, grown by metalorganic chemical vapor deposition (MOCVD), is discussed and the reliability assessment of this laser is reported. The highlights of this study include a reduction in the threshold current value for the laser to 15 mA and a degradation rate of less than 2 kW/hr for the lasers operating at 60 mW of peak output power.

  5. North American Electric Reliability Council (NERC) Reliability Coordinators

    Data.gov (United States)

    Department of Homeland Security — ERC is an international regulatory authority that works to improve the reliability of the bulk power system in North America. NERC works with many different regional...

  6. Improving the Use of Subscores on a Test Battery: Some Reliability and Validity Evidence from the Wechsler Intelligence Scale for Children-Fourth Edition

    Science.gov (United States)

    Huang, Lan

    2015-01-01

    It is widely believed that subscores can give us more information about an examinee. Thus they can be useful in planning instructional and remedial efforts, or making vocational or academic placement decisions. However, past research has shown that subscores are often not as useful as hoped either because they do not have high reliability or…

  7. Improving the reliability of female fertility breeding values using type and milk yield traits that predict energy status in Australian Holstein cattle.

    Science.gov (United States)

    González-Recio, O; Haile-Mariam, M; Pryce, J E

    2016-01-01

    The objectives of this study were (1) to propose changing the selection criteria trait for evaluating fertility in Australia from calving interval to conception rate at d 42 after the beginning of the mating season and (2) to use type traits as early fertility predictors, to increase the reliability of estimated breeding values for fertility. The breeding goal in Australia is conception within 6 wk of the start of the mating season. Currently, the Australian model to predict fertility breeding values (expressed as a linear transformation of calving interval) is a multitrait model that includes calving interval (CVI), lactation length (LL), calving to first service (CFS), first nonreturn rate (FNRR), and conception rate. However, CVI has a lower genetic correlation with the breeding goal (conception within 6 wk of the start of the mating season) than conception rate. Milk yield, type, and fertility data from 164,318 cow sired by 4,766 bulls were used. Principal component analysis and genetic correlation estimates between type and fertility traits were used to select type traits that could subsequently be used in a multitrait analysis. Angularity, foot angle, and pin set were chosen as type traits to include in an index with the traits that are included in the multitrait fertility model: CVI, LL, CFS, FNRR, and conception rate at d 42 (CR42). An index with these 8 traits is expected to achieve an average bull first proof reliability of 0.60 on the breeding objective (conception within 6 wk of the start of the mating season) compared with reliabilities of 0.39 and 0.45 for CR42 only or the current 5-trait Australian model. Subsequently, we used the first eigenvector of a principal component analysis with udder texture, bone quality, angularity, and body condition score to calculate an energy status indicator trait. The inclusion of the energy status indicator trait composite in a multitrait index with CVI, LL, CFS, FNRR, and CR42 achieved a 12-point increase in

  8. 2015 NREL Photovoltaic Module Reliability Workshops

    Energy Technology Data Exchange (ETDEWEB)

    Kurtz, Sarah [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-09-14

    NREL's Photovoltaic (PV) Module Reliability Workshop (PVMRW) brings together PV reliability experts to share information, leading to the improvement of PV module reliability. Such improvement reduces the cost of solar electricity and promotes investor confidence in the technology--both critical goals for moving PV technologies deeper into the electricity marketplace.

  9. 2016 NREL Photovoltaic Module Reliability Workshop

    Energy Technology Data Exchange (ETDEWEB)

    Kurtz, Sarah [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-09-07

    NREL's Photovoltaic (PV) Module Reliability Workshop (PVMRW) brings together PV reliability experts to share information, leading to the improvement of PV module reliability. Such improvement reduces the cost of solar electricity and promotes investor confidence in the technology - both critical goals for moving PV technologies deeper into the electricity marketplace.

  10. Space transportation main engine reliability and safety

    Science.gov (United States)

    Monk, Jan C.

    1991-01-01

    Viewgraphs are used to illustrate the reliability engineering and aerospace safety of the Space Transportation Main Engine (STME). A technology developed is called Total Quality Management (TQM). The goal is to develop a robust design. Reducing process variability produces a product with improved reliability and safety. Some engine system design characteristics are identified which improves reliability.

  11. Reliability of Wireless Sensor Networks

    Science.gov (United States)

    Dâmaso, Antônio; Rosa, Nelson; Maciel, Paulo

    2014-01-01

    Wireless Sensor Networks (WSNs) consist of hundreds or thousands of sensor nodes with limited processing, storage, and battery capabilities. There are several strategies to reduce the power consumption of WSN nodes (by increasing the network lifetime) and increase the reliability of the network (by improving the WSN Quality of Service). However, there is an inherent conflict between power consumption and reliability: an increase in reliability usually leads to an increase in power consumption. For example, routing algorithms can send the same packet though different paths (multipath strategy), which it is important for reliability, but they significantly increase the WSN power consumption. In this context, this paper proposes a model for evaluating the reliability of WSNs considering the battery level as a key factor. Moreover, this model is based on routing algorithms used by WSNs. In order to evaluate the proposed models, three scenarios were considered to show the impact of the power consumption on the reliability of WSNs. PMID:25157553

  12. Software reliability studies

    Science.gov (United States)

    Hoppa, Mary Ann; Wilson, Larry W.

    1994-01-01

    There are many software reliability models which try to predict future performance of software based on data generated by the debugging process. Our research has shown that by improving the quality of the data one can greatly improve the predictions. We are working on methodologies which control some of the randomness inherent in the standard data generation processes in order to improve the accuracy of predictions. Our contribution is twofold in that we describe an experimental methodology using a data structure called the debugging graph and apply this methodology to assess the robustness of existing models. The debugging graph is used to analyze the effects of various fault recovery orders on the predictive accuracy of several well-known software reliability algorithms. We found that, along a particular debugging path in the graph, the predictive performance of different models can vary greatly. Similarly, just because a model 'fits' a given path's data well does not guarantee that the model would perform well on a different path. Further we observed bug interactions and noted their potential effects on the predictive process. We saw that not only do different faults fail at different rates, but that those rates can be affected by the particular debugging stage at which the rates are evaluated. Based on our experiment, we conjecture that the accuracy of a reliability prediction is affected by the fault recovery order as well as by fault interaction.

  13. Midwife Acceptability in Implementation of Labor Warranty Policy in the District Mojokerto

    Directory of Open Access Journals (Sweden)

    Agung Dwi Laksono

    2014-08-01

    Full Text Available Background: The existence of midwive as the Jampersal main guard so important. Midwive acceptability has become Jampersal issue’s at district level, then the reason is enough to do a policy analysis of Jampersal.It is important to ensure successful implementation in the field, so the aim of improving access to maternal and child health services, as well as further reduction of MMR and IMR can be achieved. This study aimed to analyze the midwifes acceptability to the implementation of Jampersal in Mojokerto regency. Methods: This research is observational study. This study is also the policy analysis research on policy implementation stage.Policy research is classified as an ‘analysis of policy’. In-depth interviews and focus group discussions withthe data obtained from the field actors. Content analysis is done by analyzing the acceptability of thematically based midwives in Mojokerto regency to the Jampersal membership, benefit package, accountability, and the tariff. Result: Research shows that midwives most accept to the Jampersal accountability. It is perceived more easily than other health financing. For the acceptability of the benefit package and the tariff, midwives could still accept although with little objection. For Jampersal membership, most midwives still objected to the Jampersal membership models. Conclution: It needs to be disseminated to a deeper understanding of the meaning and purpose of the Jampersal philosophy. Recommendation: Socialization is also able to explain what the background of every detail measures taken, including what makes the midwife objected.

  14. 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

  15. Mining a database of single amplified genomes from Red Sea brine pool extremophiles—improving reliability of gene function prediction using a profile and pattern matching algorithm (PPMA)

    Science.gov (United States)

    Grötzinger, Stefan W.; Alam, Intikhab; Ba Alawi, Wail; Bajic, Vladimir B.; Stingl, Ulrich; Eppinger, Jörg

    2014-01-01

    Reliable functional annotation of genomic data is the key-step in the discovery of novel enzymes. Intrinsic sequencing data quality problems of single amplified genomes (SAGs) and poor homology of novel extremophile's genomes pose significant challenges for the attribution of functions to the coding sequences identified. The anoxic deep-sea brine pools of the Red Sea are a promising source of novel enzymes with unique evolutionary adaptation. Sequencing data from Red Sea brine pool cultures and SAGs are annotated and stored in the Integrated Data Warehouse of Microbial Genomes (INDIGO) data warehouse. Low sequence homology of annotated genes (no similarity for 35% of these genes) may translate into false positives when searching for specific functions. The Profile and Pattern Matching (PPM) strategy described here was developed to eliminate false positive annotations of enzyme function before progressing to labor-intensive hyper-saline gene expression and characterization. It utilizes InterPro-derived Gene Ontology (GO)-terms (which represent enzyme function profiles) and annotated relevant PROSITE IDs (which are linked to an amino acid consensus pattern). The PPM algorithm was tested on 15 protein families, which were selected based on scientific and commercial potential. An initial list of 2577 enzyme commission (E.C.) numbers was translated into 171 GO-terms and 49 consensus patterns. A subset of INDIGO-sequences consisting of 58 SAGs from six different taxons of bacteria and archaea were selected from six different brine pool environments. Those SAGs code for 74,516 genes, which were independently scanned for the GO-terms (profile filter) and PROSITE IDs (pattern filter). Following stringent reliability filtering, the non-redundant hits (106 profile hits and 147 pattern hits) are classified as reliable, if at least two relevant descriptors (GO-terms and/or consensus patterns) are present. Scripts for annotation, as well as for the PPM algorithm, are available

  16. Mining a database of single amplified genomes from Red Sea brine pool extremophiles – Improving reliability of gene function prediction using a profile and pattern matching algorithm (PPMA

    Directory of Open Access Journals (Sweden)

    Stefan Wolfgang Grötzinger

    2014-04-01

    Full Text Available Reliable functional annotation of genomic data is the key-step in the discovery of novel enzymes. Intrinsic sequencing data quality problems of single amplified genomes (SAGs and poor homology of novel extremophile’s genomes pose significant challenges for the attribution of functions to the coding sequences identified. The anoxic deep-sea brine pools of the Red Sea are a promising source of novel enzymes with unique evolutionary adaptation. Sequencing data from Red Sea brine pool cultures and SAGs are annotated and stored in the INDIGO data warehouse. Low sequence homology of annotated genes (no similarity for 35% of these genes may translate into false positives when searching for specific functions. The Profile & Pattern Matching (PPM strategy described here was developed to eliminate false positive annotations of enzyme function before progressing to labor-intensive hyper-saline gene expression and characterization. It utilizes InterPro-derived Gene Ontology (GO-terms (which represent enzyme function profiles and annotated relevant PROSITE IDs (which are linked to an amino acid consensus pattern. The PPM algorithm was tested on 15 protein families, which were selected based on scientific and commercial potential. An initial list of 2,577 E.C. numbers was translated into 171 GO-terms and 49 consensus patterns. A subset of INDIGO-sequences consisting of 58 SAGs from six different taxons of bacteria and archaea were selected from 6 different brine pool environments. Those SAGs code for 74,516 genes, which were independently scanned for the GO-terms (profile filter and PROSITE IDs (pattern filter. Following stringent reliability filtering, the non-redundant hits (106 profile hits and 147 pattern hits are classified as reliable, if at least two relevant descriptors (GO-terms and/or consensus patterns are present. Scripts for annotation, as well as for the PPM algorithm, are available through the INDIGO website.

  17. Mining a database of single amplified genomes from Red Sea brine pool extremophiles-improving reliability of gene function prediction using a profile and pattern matching algorithm (PPMA).

    KAUST Repository

    Grötzinger, Stefan W.

    2014-04-07

    Reliable functional annotation of genomic data is the key-step in the discovery of novel enzymes. Intrinsic sequencing data quality problems of single amplified genomes (SAGs) and poor homology of novel extremophile\\'s genomes pose significant challenges for the attribution of functions to the coding sequences identified. The anoxic deep-sea brine pools of the Red Sea are a promising source of novel enzymes with unique evolutionary adaptation. Sequencing data from Red Sea brine pool cultures and SAGs are annotated and stored in the Integrated Data Warehouse of Microbial Genomes (INDIGO) data warehouse. Low sequence homology of annotated genes (no similarity for 35% of these genes) may translate into false positives when searching for specific functions. The Profile and Pattern Matching (PPM) strategy described here was developed to eliminate false positive annotations of enzyme function before progressing to labor-intensive hyper-saline gene expression and characterization. It utilizes InterPro-derived Gene Ontology (GO)-terms (which represent enzyme function profiles) and annotated relevant PROSITE IDs (which are linked to an amino acid consensus pattern). The PPM algorithm was tested on 15 protein families, which were selected based on scientific and commercial potential. An initial list of 2577 enzyme commission (E.C.) numbers was translated into 171 GO-terms and 49 consensus patterns. A subset of INDIGO-sequences consisting of 58 SAGs from six different taxons of bacteria and archaea were selected from six different brine pool environments. Those SAGs code for 74,516 genes, which were independently scanned for the GO-terms (profile filter) and PROSITE IDs (pattern filter). Following stringent reliability filtering, the non-redundant hits (106 profile hits and 147 pattern hits) are classified as reliable, if at least two relevant descriptors (GO-terms and/or consensus patterns) are present. Scripts for annotation, as well as for the PPM algorithm, are available

  18. IMPROVING THE RELIABILITY OF THE POWER CIRCUIT OF THE ELECTRIC TRAINS ЕР2Т AND ЕПЛ2Т

    Directory of Open Access Journals (Sweden)

    N. H. Visin

    2010-02-01

    Full Text Available The transitional processes in shunt circuit of traction engines, which armatures and excitation windings are connected in non-conducting direction as to the flowing power current, are considered in this paper. The changes in the control circuits of braking switch and in the shunt power circuit of traction engines with additional mounting a resistor of 0.5 Ohm are proposed. All this modernization will allow increasing greatly the operation reliability of power circuit of ЭР2Т and ЕПЛ2Т electric locomotives during their service life.

  19. 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.

  20. Improved linearity and reliability in GaN metal-oxide-semiconductor high-electron-mobility transistors using nanolaminate La2O3/SiO2 gate dielectric

    Science.gov (United States)

    Hsu, Ching-Hsiang; Shih, Wang-Cheng; Lin, Yueh-Chin; Hsu, Heng-Tung; Hsu, Hisang-Hua; Huang, Yu-Xiang; Lin, Tai-Wei; Wu, Chia-Hsun; Wu, Wen-Hao; Maa, Jer-Shen; Iwai, Hiroshi; Kakushima, Kuniyuki; Chang, Edward Yi

    2016-04-01

    Improved device performance to enable high-linearity power applications has been discussed in this study. We have compared the La2O3/SiO2 AlGaN/GaN metal-oxide-semiconductor high-electron-mobility transistors (MOS-HEMTs) with other La2O3-based (La2O3/HfO2, La2O3/CeO2 and single La2O3) MOS-HEMTs. It was found that forming lanthanum silicate films can not only improve the dielectric quality but also can improve the device characteristics. The improved gate insulation, reliability, and linearity of the 8 nm La2O3/SiO2 MOS-HEMT were demonstrated.

  1. Reliability evaluation of smart distribution grids

    OpenAIRE

    Kazemi, Shahram

    2011-01-01

    The term "Smart Grid" generally refers to a power grid equipped with the advanced technologies dedicated for purposes such as reliability improvement, ease of control and management, integrating of distributed energy resources and electricity market operations. Improving the reliability of electric power delivered to the end users is one of the main targets of employing smart grid technologies. The smart grid investments targeted for reliability improvement can be directed toward the generati...

  2. Towards improving the reliability of future regional climate projections: A bias-correction method applied to precipitation over the west coast of Norway

    Science.gov (United States)

    Valved, A.; Barstad, I.; Sobolowski, S.

    2012-04-01

    The early winter of 2011/2012 in the city of Bergen, located on the west coast of Norway, was dominated by warm, wet and extreme weather. This might be a glimpse of future average climate conditions under continued atmospheric warming and an enhanced hydrological cycle. The extreme weather events have resulted in drainage/sewage problems, landslides, flooding property damage and even death. As the Municipality plans for the future they must contend with a growing population in a geographically complex area in addition to any effects attributable to climate change. While the scientific community is increasingly confident in the projections of large scale changes over the mid - high latitudes this confidence does not extend to the local - regional scale where the magnitude and even direction of change may be highly uncertain. Meanwhile it is precisely these scales that Municipalities such as Bergen require information if they are to plan effectively. Thus, there is a need for reliable, local climate projections, which can aid policy makers and planners in decision-making. Current state of the art regional climate models are capable of providing detailed simulations on the order of 1 or 10km. However, due to the increased computational demands of these simulations, large ensembles, such as those used for GCM experiments, are often not possible. Thus, greater detail, under these circumstances, does not necessarily correspond to greater reliability. One way to deal with this issue is to apply a statistical bias correction method where model results are fitted to observationally derived probability density functions (pdfs). In this way, a full distribution of potential changes may be generated which are constrained by known, observed data.This will result in a shifted model distribution with mean and spread that more closely follows observations. In short, the method temporarily removes the climate signals from the model run working on the different percentiles, fits the

  3. Advanced control systems to improve nuclear power plant reliability and efficiency. Working material. Report of an advisory group meeting held in Vienna, 13-17 March, 1995

    International Nuclear Information System (INIS)

    1995-01-01

    The Advisory Group Meeting as a consequence of the recommendations of the IAEA International Working Group on Nuclear Power Plant Control and Instrumentation to produce a practical guidance on the application of the advanced control systems available for nuclear power plant operation. The objective of the IAEA advisory group meeting were: To provide an international forum of exchange of ideas and views for the purpose of enhancement of nuclear power plant reliability and efficiency by adopting advanced control technologies; to develop a scope, table of content, and extended outlines for an IAEA technical document on the subject. The present volume contains summary report, materials prepared by the meeting, and reports presented by national delegates. Refs, figs and tabs

  4. Improvement of reliability and speed of phase change memory devices with N7.9(Ge46.9Bi7.2Te45.9 films

    Directory of Open Access Journals (Sweden)

    J. H. Park

    2015-08-01

    Full Text Available In this study, we propose a nitrogen-incorporated GeBiTe ternary phase of N7.9(Ge46.9Bi7.2Te45.9 as a phase change material for reliable PCM (Phase Change Memory with high speed operation. We found that the N7.9(Ge46.9Bi7.2Te45.9 film shows the resistance value of 40 kΩ after annealing at 440oC for 10 minutes, which is much higher than the value of 3.4 kΩ in the case of conventional N7.0(Ge22.0Sb22.0Te56.0 films. A set operation time of 14 nsec was achieved in the devices due to the increased probability of the nucleation by the addition of the elemental Bi. The long data retention time of 10 years at 85oC on the base of 1% failure was obtained as the result of higher activation energy of 2.52 eV for the crystallization compared to the case of N7.0(Ge22.0Sb22.0Te56.0 film, in which the activation energy is 2.1 eV. In addition, a reset current reduction of 27% and longer cycles of endurance as much as 2 order of magnitude compared to the case of N7.0(Ge22.0Sb22.0Te56.0 were observed at a set operation time of 14 nsec. Our results show that N7.9(Ge46.9Bi7.2Te45.9 is highly promising for use as a phase change material in reliable PCMs with high performance and also in forthcoming storage class memory applications, too.

  5. Improvement of reliability and speed of phase change memory devices with N7.9(Ge46.9Bi7.2Te45.9) films

    Science.gov (United States)

    Park, J. H.; Kim, S.-W.; Kim, J. H.; Ko, D.-H.; Wu, Z.; Cho, S. L.; Ahn, D.; Ahn, D. H.; Lee, J. M.; Nam, S. W.

    2015-08-01

    In this study, we propose a nitrogen-incorporated GeBiTe ternary phase of N7.9(Ge46.9Bi7.2Te45.9) as a phase change material for reliable PCM (Phase Change Memory) with high speed operation. We found that the N7.9(Ge46.9Bi7.2Te45.9) film shows the resistance value of 40 kΩ after annealing at 440oC for 10 minutes, which is much higher than the value of 3.4 kΩ in the case of conventional N7.0(Ge22.0Sb22.0Te56.0) films. A set operation time of 14 nsec was achieved in the devices due to the increased probability of the nucleation by the addition of the elemental Bi. The long data retention time of 10 years at 85oC on the base of 1% failure was obtained as the result of higher activation energy of 2.52 eV for the crystallization compared to the case of N7.0(Ge22.0Sb22.0Te56.0) film, in which the activation energy is 2.1 eV. In addition, a reset current reduction of 27% and longer cycles of endurance as much as 2 order of magnitude compared to the case of N7.0(Ge22.0Sb22.0Te56.0) were observed at a set operation time of 14 nsec. Our results show that N7.9(Ge46.9Bi7.2Te45.9) is highly promising for use as a phase change material in reliable PCMs with high performance and also in forthcoming storage class memory applications, too.

  6. 76 FR 66057 - North American Electric Reliability Corporation; Order Approving Regional Reliability Standard

    Science.gov (United States)

    2011-10-25

    ... Reliability Standard that is necessitated by a physical difference in the Bulk-Power System.\\7\\ \\7\\ Order No... Reliability Standards for the Bulk-Power System, Order No. 693, FERC Stats. & Regs. ] 31,242, order on reh'g... electric system event analyses and thereby improve system reliability by promoting improved system design...

  7. Suggested improvements to the definitions of Standardized Plant Analysis of Risk-Human Reliability Analysis (SPAR-H) performance shaping factors, their levels and multipliers and the nominal tasks

    International Nuclear Information System (INIS)

    Laumann, Karin; Rasmussen, Martin

    2016-01-01

    This paper discusses the definitions and content of eight performance shaping factors (PSFs) used in Standardized Plant Analysis of Risk-Human Reliability Analysis (SPAR-H) and their levels and multipliers. Definitions of nominal tasks are also discussed. The discussion is based on a review of literature on PSFs, interviews with consultants who have carried out SPAR-H analysis in the petroleum industry and an evaluation of human reliability analysis reports based on SPAR-H analysis. We concluded that SPAR-H definitions and descriptions of the PSFs are unclear and overlap too much, making it difficult for the analyst to choose between them and select the appropriate level. This reduces inter-rater reliability and thus the consistency of SPAR-H analyses. New definitions of the PSFs, levels and multipliers are suggested with the aim to develop more specific definitions of the PSFs in order to increase the inter-rater reliability of SPAR-H. Another aim was to construct more varied and more nuanced levels and multipliers to improve the capacity of SPAR-H analysis to capture the degree of difficulty faced by operators in different scenarios. We also suggest that only one of two nominal SPAR-H tasks should be retained owing to the difficulty in distinguishing between them. - Highlights: • The SPAR-H guidelines should be revised. • Descriptions of the PSFs should be improved. • New definitions should reduce overlap between the PSFs. • The multipliers are based on an “old” method and should be revised. • Some PSF levels and multipliers in SPAR-H are not logical.

  8. Aerospace reliability applied to biomedicine.

    Science.gov (United States)

    Lalli, V. R.; Vargo, D. J.

    1972-01-01

    An analysis is presented that indicates that the reliability and quality assurance methodology selected by NASA to minimize failures in aerospace equipment can be applied directly to biomedical devices to improve hospital equipment reliability. The Space Electric Rocket Test project is used as an example of NASA application of reliability and quality assurance (R&QA) methods. By analogy a comparison is made to show how these same methods can be used in the development of transducers, instrumentation, and complex systems for use in medicine.

  9. 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.

  10. 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.)

  11. 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

  12. AMSAA Reliability Growth Guide

    National Research Council Canada - National Science Library

    Broemm, William

    2000-01-01

    ... has developed reliability growth methodology for all phases of the process, from planning to tracking to projection. The report presents this methodology and associated reliability growth concepts.

  13. Methods for qualification of highly reliable software - international procedure

    International Nuclear Information System (INIS)

    Kersken, M.

    1997-01-01

    Despite the advantages of computer-assisted safety technology, there still is some uneasyness to be observed with respect to the novel processes, resulting from absence of a body of generally accepted and uncontentious qualification guides (regulatory provisions, standards) for safety evaluation of the computer codes applied. Warranty of adequate protection of the population, operators or plant components is an essential aspect in this context, too - as it is in general with reliability and risk assessment of novel technology - so that, due to appropriate legislation still missing, there currently is a licensing risk involved in the introduction of digital safety systems. Nevertheless, there is some extent of agreement within the international community and utility operators about what standards and measures should be applied for qualification of software of relevance to plant safety. The standard IEC 880/IEC 86/ in particular, in its original version, or national documents based on this standard, are applied in all countries using or planning to install those systems. A novel supplement to this standard, document /IEC 96/, is in the process of finalization and defines the requirements to be met by modern methods of software engineering. (orig./DG) [de

  14. Audio-Visual Biofeedback Does Not Improve the Reliability of Target Delineation Using Maximum Intensity Projection in 4-Dimensional Computed Tomography Radiation Therapy Planning

    International Nuclear Information System (INIS)

    Lu, Wei; Neuner, Geoffrey A.; George, Rohini; Wang, Zhendong; Sasor, Sarah; Huang, Xuan; Regine, William F.; Feigenberg, Steven J.; D'Souza, Warren D.

    2014-01-01

    Purpose: To investigate whether coaching patients' breathing would improve the match between ITV MIP (internal target volume generated by contouring in the maximum intensity projection scan) and ITV 10 (generated by combining the gross tumor volumes contoured in 10 phases of a 4-dimensional CT [4DCT] scan). Methods and Materials: Eight patients with a thoracic tumor and 5 patients with an abdominal tumor were included in an institutional review board-approved prospective study. Patients underwent 3 4DCT scans with: (1) free breathing (FB); (2) coaching using audio-visual (AV) biofeedback via the Real-Time Position Management system; and (3) coaching via a spirometer system (Active Breathing Coordinator or ABC). One physician contoured all scans to generate the ITV 10 and ITV MIP . The match between ITV MIP and ITV 10 was quantitatively assessed with volume ratio, centroid distance, root mean squared distance, and overlap/Dice coefficient. We investigated whether coaching (AV or ABC) or uniform expansions (1, 2, 3, or 5 mm) of ITV MIP improved the match. Results: Although both AV and ABC coaching techniques improved frequency reproducibility and ABC improved displacement regularity, neither improved the match between ITV MIP and ITV 10 over FB. On average, ITV MIP underestimated ITV 10 by 19%, 19%, and 21%, with centroid distance of 1.9, 2.3, and 1.7 mm and Dice coefficient of 0.87, 0.86, and 0.88 for FB, AV, and ABC, respectively. Separate analyses indicated a better match for lung cancers or tumors not adjacent to high-intensity tissues. Uniform expansions of ITV MIP did not correct for the mismatch between ITV MIP and ITV 10 . Conclusions: In this pilot study, audio-visual biofeedback did not improve the match between ITV MIP and ITV 10 . In general, ITV MIP should be limited to lung cancers, and modification of ITV MIP in each phase of the 4DCT data set is recommended

  15. Discussion on an informative system set-up for the registration and processing of reliability data on FBR components in view of its application to design and safety studies and plant exploitation improvement

    International Nuclear Information System (INIS)

    Righini, R.; Sola, P.G.; Zappellini, G.

    1990-01-01

    This report describes the set-up and management activities carried-out by ENEA-VEL in collaboration with NIER in the development of a reliability data bank on fast reactor components; this data bank consists of an informative system implemented on the IBM 3090 computer of the ENEA centre of Bologna starting from the software of the CEDB, set-up by CCR Euratom of Ispra for the registration of reliability data on thermal reactor components. This report will contain a detailed description of all the modules (engineering, operating, etc.) provided in the informative system and of the modifications introduced by ENEA in order to adapt them to the peculiarities of the fast reactors and to increase its flexibility; a short description of the available data processing methods will be also included. It will be followed by a comparison between the results obtained applying the classical methods and the particular ones set-up by ENEA: this comparison will be useful to demonstrate the importance of the method applied in order to obtain significative reliability processed data. This report will be also useful to show the importance of the set-up data bank in the improvement of the component design and of the plant safety and exploitation with particular reference to the research of the critical areas and to the definition of the best inspection and maintenance programs

  16. A novel molecular diagnostic tool for improved sensitivity and reliability detection of “Candidatus Liberibacter asiaticus”, bacterium associated with huanglongbing (HLB) bacterium Candidatus Liberibacter.

    Science.gov (United States)

    Sensitive and accurate detection is a prerequisite for efficient management and regulatory responses to prevent the introduction and spread of HLB-associated “Candidatus Liberibacter species to unaffected areas. To improve the current detection limit of HLB-associated “Ca. Liberibacter” spp, we deve...

  17. 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)

  18. A method for improving reliability and relevance of LCA reviews: the case of life-cycle greenhouse gas emissions of tap and bottled water.

    Science.gov (United States)

    Fantin, Valentina; Scalbi, Simona; Ottaviano, Giuseppe; Masoni, Paolo

    2014-04-01

    The purpose of this study is to propose a method for harmonising Life Cycle Assessment (LCA) literature studies on the same product or on different products fulfilling the same function for a reliable and meaningful comparison of their life-cycle environmental impacts. The method is divided in six main steps which aim to rationalize and quicken the efforts needed to carry out the comparison. The steps include: 1) a clear definition of the goal and scope of the review; 2) critical review of the references; 3) identification of significant parameters that have to be harmonised; 4) harmonisation of the parameters; 5) statistical analysis to support the comparison; 6) results and discussion. This approach was then applied to the comparative analysis of the published LCA studies on tap and bottled water production, focussing on Global Warming Potential (GWP) results, with the aim to identify the environmental preferable alternative. A statistical analysis with Wilcoxon's test confirmed that the difference between harmonised GWP values of tap and bottled water was significant. The results obtained from the comparison of the harmonised mean GWP results showed that tap water always has the best environmental performance, even in case of high energy-consuming technologies for drinking water treatments. The strength of the method is that it enables both performing a deep analysis of the LCA literature and obtaining more consistent comparisons across the published LCAs. For these reasons, it can be a valuable tool which provides useful information for both practitioners and decision makers. Finally, its application to the case study allowed both to supply a description of systems variability and to evaluate the importance of several key parameters for tap and bottled water production. The comparative review of LCA studies, with the inclusion of a statistical decision test, can validate and strengthen the final statements of the comparison. Copyright © 2014 Elsevier B.V. All

  19. Audio-Visual Biofeedback Does Not Improve the Reliability of Target Delineation Using Maximum Intensity Projection in 4-Dimensional Computed Tomography Radiation Therapy Planning

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Wei, E-mail: wlu@umm.edu [Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, Maryland (United States); Neuner, Geoffrey A.; George, Rohini; Wang, Zhendong; Sasor, Sarah [Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, Maryland (United States); Huang, Xuan [Research and Development, Care Management Department, Johns Hopkins HealthCare LLC, Glen Burnie, Maryland (United States); Regine, William F.; Feigenberg, Steven J.; D' Souza, Warren D. [Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, Maryland (United States)

    2014-01-01

    Purpose: To investigate whether coaching patients' breathing would improve the match between ITV{sub MIP} (internal target volume generated by contouring in the maximum intensity projection scan) and ITV{sub 10} (generated by combining the gross tumor volumes contoured in 10 phases of a 4-dimensional CT [4DCT] scan). Methods and Materials: Eight patients with a thoracic tumor and 5 patients with an abdominal tumor were included in an institutional review board-approved prospective study. Patients underwent 3 4DCT scans with: (1) free breathing (FB); (2) coaching using audio-visual (AV) biofeedback via the Real-Time Position Management system; and (3) coaching via a spirometer system (Active Breathing Coordinator or ABC). One physician contoured all scans to generate the ITV{sub 10} and ITV{sub MIP}. The match between ITV{sub MIP} and ITV{sub 10} was quantitatively assessed with volume ratio, centroid distance, root mean squared distance, and overlap/Dice coefficient. We investigated whether coaching (AV or ABC) or uniform expansions (1, 2, 3, or 5 mm) of ITV{sub MIP} improved the match. Results: Although both AV and ABC coaching techniques improved frequency reproducibility and ABC improved displacement regularity, neither improved the match between ITV{sub MIP} and ITV{sub 10} over FB. On average, ITV{sub MIP} underestimated ITV{sub 10} by 19%, 19%, and 21%, with centroid distance of 1.9, 2.3, and 1.7 mm and Dice coefficient of 0.87, 0.86, and 0.88 for FB, AV, and ABC, respectively. Separate analyses indicated a better match for lung cancers or tumors not adjacent to high-intensity tissues. Uniform expansions of ITV{sub MIP} did not correct for the mismatch between ITV{sub MIP} and ITV{sub 10}. Conclusions: In this pilot study, audio-visual biofeedback did not improve the match between ITV{sub MIP} and ITV{sub 10}. In general, ITV{sub MIP} should be limited to lung cancers, and modification of ITV{sub MIP} in each phase of the 4DCT data set is recommended.

  20. Improvements of visual X-ray inspection with optimized digital detector technology. Faster and more reliable inspection with High Dynamic Radiology (HDR)

    International Nuclear Information System (INIS)

    Bavendiek, Klaus

    2010-01-01

    Improvements in speed and contrast resolution of Digital Detector Arrays (DDA) and significant higher power of X-Ray tubes in combination with a small focal spot open the door to an improved visual inspection of castings for automotive and aerospace applications. The result is a film-like image quality of castings in a live view. For the new image quality the x-ray parameter have to be optimized in energy and the subject contrast has to be increased to avoid that flaws are covered by the noise in the image. HDR - high dynamic radiology - expands the local contrast in the image and transfers the grey values to the range the human inspector can separate. Due to the movement in the image the inspector gets a glas-like impression of the object and the flaws allowing him to do a decision about the 3D position of a flaw in the object. (orig.)

  1. A risk-informed approach of quantification of epistemic uncertainty for the long-term radioactive waste disposal. Improving reliability of expert judgements with an advanced elicitation procedure

    International Nuclear Information System (INIS)

    Sugiyama, Daisuke; Chida, Taiji; Fujita, Tomonari; Tsukamoto, Masaki

    2011-01-01

    A quantification methodology of epistemic uncertainty by expert judgement based on the risk-informed approach is developed to assess inevitable uncertainty for the long-term safety assessment of radioactive waste disposal. The proposed method in this study employs techniques of logic tree, by which options of models and/or scenarios are identified, and Evidential Support Logic (ESL), by which possibility of each option is quantified. In this report, the effect of a feedback process of discussion between experts and input of state-of-the-art knowledge in the proposed method is discussed to estimate alteration of the distribution of expert judgements which is one of the factors causing uncertainty. In a preliminary quantification experiment of uncertainty of degradation of the engineering barrier materials in a tentative sub-surface disposal using the proposed methodology, experts themselves modified questions appropriately to facilitate sound judgements and to correlate those with scientific evidences clearly. The result suggests that the method effectively improves confidence of expert judgement. Also, the degree of consensus of expert judgement was sort of improved in some cases, since scientific knowledge and information of expert judgement in other fields became common understanding. It is suggested that the proposed method could facilitate consensus on uncertainty between interested persons. (author)

  2. El análisis de criticidad, una metodología para mejorar la confiabilidad operacional // Criticality analysis , a methodology to improve the operational reliability.

    Directory of Open Access Journals (Sweden)

    R. Huerta Mendoza

    2000-10-01

    establecer prioridades, yfocalizar el esfuerzo que garantice el éxito maximizando la rentabilidad.Palabras claves: confiabilidad, criticidad, seguridad, ambiente, riesgo, disponibilidad, mejoramiento.___________________________________________________________________Abstract:The criticality analysis is a methodology that allows to establish the hierarchy or priorities of processes, systems andequipments, creating a structure that facilitates the taking of effective and correct decisions, addressing the effort and theresources in areas where it is more important or necessary to improve the operational dependability, based on the currentreality.The improvement of the operational dependability of any installation or their systems and components is associated withfour fundamental aspects: human dependability, dependability of the process, dependability of the design and thedependability of the maintenance. Regrettably, difficultly is in our hands limitless resources, so much economic as human,to be able to improve at the same time, these four aspects in all the areas of a company.The approaches to carry out a criticality analysis are associated with: security, surroundings, production, operation costsand maintenance, failure rate and repair time mainly. These approaches are related with a mathematical equation thatgenerates punctuation for each evaluated element.The generated list, result of a team work, allows to even and to homologate approaches to establish priorities, and focalisethe effort that guarantees the success maximizing the profitability..Key words:. PDVSA, dependability, criticality, security, surroundings, risk, readiness, improvement,changes.

  3. PV Systems Reliability Final Technical Report.

    Energy Technology Data Exchange (ETDEWEB)

    Lavrova, Olga [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Flicker, Jack David [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Johnson, Jay [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Armijo, Kenneth Miguel [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Gonzalez, Sigifredo [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Schindelholz, Eric John [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Sorensen, Neil R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Yang, Benjamin Bing-Yeh [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-12-01

    The continued exponential growth of photovoltaic technologies paves a path to a solar-powered world, but requires continued progress toward low-cost, high-reliability, high-performance photovoltaic (PV) systems. High reliability is an essential element in achieving low-cost solar electricity by reducing operation and maintenance (O&M) costs and extending system lifetime and availability, but these attributes are difficult to verify at the time of installation. Utilities, financiers, homeowners, and planners are demanding this information in order to evaluate their financial risk as a prerequisite to large investments. Reliability research and development (R&D) is needed to build market confidence by improving product reliability and by improving predictions of system availability, O&M cost, and lifetime. This project is focused on understanding, predicting, and improving the reliability of PV systems. The two areas being pursued include PV arc-fault and ground fault issues, and inverter reliability.

  4. 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)

  5. Improving the reliability of open-cycle water systems: Application of biofouling surveillance and control techniques to sediment and corrosion fouling at nuclear power plants

    International Nuclear Information System (INIS)

    Johnson, K.I.; Neitzel, D.A.

    1987-03-01

    Biofouling surveillance and control techniques are evaluated for their applicability to sediment and corrosion fouling and suggestions are given to improve their effectiveness. Alternate techniques to better detect and control sedimentation and corrosion are also evaluated. Environmental conditions that allow biofouling, sedimentation, and corrosion to occur are summarized. A correlation between sediment and corrosion is identified and the causes are described. Environmental regulations, especially those in the Clean Water Act of 1977, are reviewed to identify those that may limit or prevent the use of surveillance and control techniques described in this report. Flow velocity is the major design factor that determines whether or not biofouling, sedimentation, and corrosion will occur. Monitoring flow conditions can provide early warning of conditions that will allow fouling to occur. Visual inspection is the most common and most effective technique for identifying the cause and extent of fouling in the open-cycle water system. Most biofouling control techniques in current use are not effective against sediment and corrosion. Frequent, high-velocity flushing of cooling loops may effectively remove sediment and reduce under-sediment corrosion. Alternate biocide treatments such as targeted chlorination or the use of ozone or 2,2-dibromo-3-nitrilo propionamide (DBNPA) may also be effective in reducing under-sediment corrosion

  6. Improvements in the reliability of a-InGaZnO thin-film transistors with triple stacked gate insulator in flexible electronics applications

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Hua-Mao [Department of Photonics & Institute of Electro-Optical Engineering, National Chiao Tung University, Hsinchu, Taiwan (China); Chang, Ting-Chang, E-mail: tcchang3708@gmail.com [Department of Physics, National Sun Yat-Sen University, Kaohsiung, Taiwan (China); Department of Photonics, National Sun Yat-Sen University, Kaohsiung, Taiwan (China); Advanced Optoelectronics Technology Center, National Cheng Kung University, Taiwan (China); Tai, Ya-Hsiang [Department of Photonics & Institute of Electro-Optical Engineering, National Chiao Tung University, Hsinchu, Taiwan (China); Chen, Kuan-Fu [Department of Physics, National Sun Yat-Sen University, Kaohsiung, Taiwan (China); Chiang, Hsiao-Cheng [Department of Photonics, National Sun Yat-Sen University, Kaohsiung, Taiwan (China); Liu, Kuan-Hsien [Department of Electrophysics, National Chiao Tung University, Hsinchu, Taiwan (China); Lee, Chao-Kuei [Department of Photonics, National Sun Yat-Sen University, Kaohsiung, Taiwan (China); Lin, Wei-Ting; Cheng, Chun-Cheng; Tu, Chun-Hao; Liu, Chu-Yu [Advanced Technology Research Center, AU Optronics Corp, Hsinchu, Taiwan (China)

    2015-11-30

    This study examined the impact of the low-temperature stacking gate insulator on the gate bias instability of a-InGaZnO thin film transistors in flexible electronics applications. Although the quality of SiN{sub x} at low process/deposition temperature is better than that of SiO{sub x} at similarly low process/deposition temperature, there is still a very large positive threshold voltage (V{sub th}) shift of 9.4 V for devices with a single low-temperature SiN{sub x} gate insulator under positive gate bias stress. However, a suitable oxide–nitride–oxide-stacked gate insulator exhibits a V{sub th} shift of only 0.23 V. This improvement results from the larger band offset and suitable gate insulator thickness that can effectively suppress carrier trapping behavior. - Highlights: • The cause of the bias instability for a low-temperature gate insulator is verified. • A triple-stacked gate insulator was fabricated. • A suitable triple stacked gate insulator shows only 0.23 V threshold voltage shift.

  7. INCREASED RELIABILITY OF ELECTRIC BLASTING

    OpenAIRE

    Kashuba, Oleh Ivanovych; Skliarov, L I; Skliarov, A L

    2017-01-01

    The problems of improving reliability of an electric blasting method using electric detonators with nichrome filament bridges. It was revealed that in the calculation of the total resistance of the explosive network it is necessary to increase to 24% of the nominal value

  8. Proposed Reliability/Cost Model

    Science.gov (United States)

    Delionback, L. M.

    1982-01-01

    New technique estimates cost of improvement in reliability for complex system. Model format/approach is dependent upon use of subsystem cost-estimating relationships (CER's) in devising cost-effective policy. Proposed methodology should have application in broad range of engineering management decisions.

  9. The Accelerator Reliability Forum

    CERN Document Server

    Lüdeke, Andreas; Giachino, R

    2014-01-01

    A high reliability is a very important goal for most particle accelerators. The biennial Accelerator Reliability Workshop covers topics related to the design and operation of particle accelerators with a high reliability. In order to optimize the over-all reliability of an accelerator one needs to gather information on the reliability of many different subsystems. While a biennial workshop can serve as a platform for the exchange of such information, the authors aimed to provide a further channel to allow for a more timely communication: the Particle Accelerator Reliability Forum [1]. This contribution will describe the forum and advertise it’s usage in the community.

  10. 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)

  11. Quality Improvement to Demonstrate the Lack of Reliability of the Human Papillomavirus mRNA Assay to Identify Women With Latent Human Papillomavirus Infections.

    Science.gov (United States)

    Cotton, Sarah; Brown, Robert E; Nugent, Elizabeth K; Robazetti, Sonia C; Berens, Pamela D; Smith, Judith A

    2018-04-01

    To assess the consistency between human papillomavirus (HPV) mRNA testing in women with a history of previous HPV infections diagnosed by HPV DNA assay and the potential effects on follow-up HPV screening. This was a quality improvement study that used data from a pathology laboratory software database reviewed from November 2014 to June 2016 to identify female patients aged 30 years or older with greater than one HPV-positive result, including one or more HPV mRNA assay results and one or more documented HPV DNA assay results for comparison. Previous correlative cytology and colposcopic histopathology were also documented. American College of Obstetricians and Gynecologists' cervical cancer screening guidelines were used to compare potential differences in follow-up recommendations. Four hundred twenty-five charts for female patients 30 years of age or older were identified with one or more prior high-risk HPV infections by DNA assay. There was a 69.3% difference in HPV mRNA results compared with previous HPV DNA-positive results. There was a potential change in follow-up for 71.7% of patients with one prior high-risk-HPV-positive result and 60.0% of patients with two or more prior high-risk HPV-positive results. There were 231 colposcopy reports evaluated in this study. Of these, 62 (26.8%) were abnormal colposcopy reports, including 45 low-grade squamous intraepithelial lesions, 15 high-grade squamous intraepithelial lesions, and two cancers. Twenty-five (40.3%) abnormal colposcopy findings were in patients with a history of at least than two prior HPV DNA-positive results and a report of currently being HPV-negative with the mRNA assay. The HPV mRNA assays are less sensitive for detection of latent HPV infections compared with HPV DNA assays. Based on these data and the potential change in follow-up care, the HPV mRNA assay should not be used for a primary screening tool for cervical cancer. Many pathology laboratories have shifted to using the HPV mRNA assay

  12. Developing Reliable Life Support for Mars

    Science.gov (United States)

    Jones, Harry W.

    2017-01-01

    A human mission to Mars will require highly reliable life support systems. Mars life support systems may recycle water and oxygen using systems similar to those on the International Space Station (ISS). However, achieving sufficient reliability is less difficult for ISS than it will be for Mars. If an ISS system has a serious failure, it is possible to provide spare parts, or directly supply water or oxygen, or if necessary bring the crew back to Earth. Life support for Mars must be designed, tested, and improved as needed to achieve high demonstrated reliability. A quantitative reliability goal should be established and used to guide development t. The designers should select reliable components and minimize interface and integration problems. In theory a system can achieve the component-limited reliability, but testing often reveal unexpected failures due to design mistakes or flawed components. Testing should extend long enough to detect any unexpected failure modes and to verify the expected reliability. Iterated redesign and retest may be required to achieve the reliability goal. If the reliability is less than required, it may be improved by providing spare components or redundant systems. The number of spares required to achieve a given reliability goal depends on the component failure rate. If the failure rate is under estimated, the number of spares will be insufficient and the system may fail. If the design is likely to have undiscovered design or component problems, it is advisable to use dissimilar redundancy, even though this multiplies the design and development cost. In the ideal case, a human tended closed system operational test should be conducted to gain confidence in operations, maintenance, and repair. The difficulty in achieving high reliability in unproven complex systems may require the use of simpler, more mature, intrinsically higher reliability systems. The limitations of budget, schedule, and technology may suggest accepting lower and

  13. Human Reliability Program Overview

    Energy Technology Data Exchange (ETDEWEB)

    Bodin, Michael

    2012-09-25

    This presentation covers the high points of the Human Reliability Program, including certification/decertification, critical positions, due process, organizational structure, program components, personnel security, an overview of the US DOE reliability program, retirees and academia, and security program integration.

  14. Reliability of software

    International Nuclear Information System (INIS)

    Kopetz, H.

    1980-01-01

    Common factors and differences in the reliability of hardware and software; reliability increase by means of methods of software redundancy. Maintenance of software for long term operating behavior. (HP) [de

  15. Reliable Design Versus Trust

    Science.gov (United States)

    Berg, Melanie; LaBel, Kenneth A.

    2016-01-01

    This presentation focuses on reliability and trust for the users portion of the FPGA design flow. It is assumed that the manufacturer prior to hand-off to the user tests FPGA internal components. The objective is to present the challenges of creating reliable and trusted designs. The following will be addressed: What makes a design vulnerable to functional flaws (reliability) or attackers (trust)? What are the challenges for verifying a reliable design versus a trusted design?

  16. Pocket Handbook on Reliability

    Science.gov (United States)

    1975-09-01

    exponencial distributions Weibull distribution, -xtimating reliability, confidence intervals, relia- bility growth, 0. P- curves, Bayesian analysis. 20 A S...introduction for those not familiar with reliability and a good refresher for those who are currently working in the area. LEWIS NERI, CHIEF...includes one or both of the following objectives: a) prediction of the current system reliability, b) projection on the system reliability for someI future

  17. Principles of Bridge Reliability

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle; Nowak, Andrzej S.

    The paper gives a brief introduction to the basic principles of structural reliability theory and its application to bridge engineering. Fundamental concepts like failure probability and reliability index are introduced. Ultimate as well as serviceability limit states for bridges are formulated......, and as an example the reliability profile and a sensitivity analyses for a corroded reinforced concrete bridge is shown....

  18. Reliability in engineering '87

    International Nuclear Information System (INIS)

    Tuma, M.

    1987-01-01

    The participants heard 51 papers dealing with the reliability of engineering products. Two of the papers were incorporated in INIS, namely ''Reliability comparison of two designs of low pressure regeneration of the 1000 MW unit at the Temelin nuclear power plant'' and ''Use of probability analysis of reliability in designing nuclear power facilities.''(J.B.)

  19. Health Complaints Associated with Poor Rental Housing Conditions in Arkansas: The Only State without a Landlord’s Implied Warranty of Habitability

    Science.gov (United States)

    Bachelder, Ashley E.; Stewart, M. Kate; Felix, Holly C.; Sealy, Neil

    2016-01-01

    Arkansas is the only U.S. state that does not have a landlord’s implied warranty of habitability, meaning tenants have a requirement for maintaining their rental properties at certain habitability standards, but landlords are not legally required to contribute to those minimum health and safety standards. This project assessed the possibility that this lack of landlord responsibility affects tenants’ perceived health. Using surveys and interviews, we collected self-reported data on the prevalence and description of problems faced by renters who needed household repairs from their landlords. Of almost 1,000 renters, one-third of them had experienced a problem with their landlord making needed repairs; and one-quarter of those had a health issue they attributed to their housing conditions. Common issues included problems with plumbing, heating, or cooling systems, and pest or rodent control. Reported health problems included elevated stress levels, breathing problems, headaches, high blood pressure, and bites or infections. Hispanic respondents and those with less than a high school education were both significantly more likely to report problems with their landlords not making repairs as requested. These data suggest that the lack of landlord requirements may negatively impact the condition of rental properties and, therefore, may negatively impact the health of Arkansas renters. PMID:27933288

  20. Health Complaints Associated with Poor Rental Housing Conditions in Arkansas: The Only State Without a Landlord’s Implied Warranty of Habitability

    Directory of Open Access Journals (Sweden)

    Ashley Bachelder

    2016-11-01

    Full Text Available Arkansas is the only U.S. state that does not have a landlord’s implied warranty of habitability, meaning tenants have a requirement for maintaining their rental properties at certain habitability standards, but landlords are not legally required to contribute to those minimum health and safety standards. This project assessed the possibility that this lack of landlord responsibility affects tenants’ perceived health. Using surveys and interviews, we collected self-reported data on the prevalence and description of problems faced by renters who needed household repairs from their landlords. Of almost 1000 renters, one third of them had experienced a problem with their landlord making needed repairs; and one-quarter of those had a health issue they attributed to their housing conditions. Common issues included problems with plumbing, heating or cooling systems, and pest or rodent control. Reported health problems included elevated stress levels, breathing problems, headaches, high blood pressure and bites or infections. Hispanic respondents and those with less than a high school education were both significantly more likely to report problems with their landlords not making repairs as requested. The data suggest that the lack of landlord requirements may negatively impact the condition of rental properties, and therefore may negatively impact the health of Arkansas renters.