Sample records for reliable detection systems

  1. PV Systems Reliability Final Technical Report: Ground Fault Detection

    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)


    We have examined ground faults in PhotoVoltaic (PV) arrays and the efficacy of fuse, current detection (RCD), current sense monitoring/relays (CSM), isolation/insulation (Riso) monitoring, and Ground Fault Detection and Isolation (GFID) using simulations based on a Simulation Program with Integrated Circuit Emphasis SPICE ground fault circuit model, experimental ground faults installed on real arrays, and theoretical equations.

  2. Efficient Structural System Reliability Updating with Subspace-Based Damage Detection Information

    Döhler, Michael; Thöns, Sebastian

    modelling is introduced building upon the non-destructive testing reliability which applies to structural systems and DDS containing a strategy to overcome the high computational efforts for the pre-determination of the DDS reliability. This approach takes basis in the subspace-based damage detection method......Damage detection systems and algorithms (DDS and DDA) provide information of the structural system integrity in contrast to e.g. local information by inspections or non-destructive testing techniques. However, the potential of utilizing DDS information for the structural integrity assessment...... and prognosis is hardly exploited nor treated in scientific literature up to now. In order to utilize the information provided by DDS for the structural performance, usually high computational efforts for the pre-determination of DDS reliability are required. In this paper, an approach for the DDS performance...

  3. Application of Petri nets to reliability prediction of occupant safety systems with partial detection and repair

    Kleyner, Andre, E-mail: [Delphi Corporation, Electronics and Safety Division, P.O. Box 9005, M.S. CTC 2E, Kokomo, IN 46904 (United States); Volovoi, Vitali, E-mail: vitali.volovoi@ae.gatech.ed [School of Aerospace Engineering, Georgia Institute of Technology, Atlanta, GA 30332 (United States)


    This paper presents an application of stochastic Petri nets (SPN) to calculate the availability of safety critical on-demand systems. Traditional methods of estimating system reliability include standards-based or field return-based reliability prediction methods. These methods do not take into account the effect of fault-detection capability and penalize the addition of detection circuitry due to the higher parts count. Therefore, calculating system availability, which can be linked to the system's probability of failure on demand (P{sub fd}), can be a better alternative to reliability prediction. The process of estimating the P{sub fd} of a safety system can be further complicated by the presence of system imperfections such as partial-fault detection by users and untimely or uncompleted repairs. Additionally, most system failures cannot be represented by Poisson process Markov chain methods, which are commonly utilized for the purposes of estimating P{sub fd}, as these methods are not well-suited for the analysis of non-Poisson failures. This paper suggests a methodology and presents a case study of SPN modeling adequately handling most of the above problems. The model will be illustrated with a case study of an automotive electronics airbag controller as an example of a safety critical on-demand system.

  4. Reliability of fluid systems

    Kopáček Jaroslav


    Full Text Available This paper focuses on the importance of detection reliability, especially in complex fluid systems for demanding production technology. The initial criterion for assessing the reliability is the failure of object (element, which is seen as a random variable and their data (values can be processed using by the mathematical methods of theory probability and statistics. They are defined the basic indicators of reliability and their applications in calculations of serial, parallel and backed-up systems. For illustration, there are calculation examples of indicators of reliability for various elements of the system and for the selected pneumatic circuit.

  5. Reliability of Physical Systems: Detection of Malicious Subcircuits (Trojan Circuits) in Sequential Circuits

    Matrosova, A. Yu.; Kirienko, I. E.; Tomkov, V. V.; Miryutov, A. A.


    Reliability of physical systems is provided by reliability of their parts including logical ones. Insertion of malicious subcircuits that can destroy logical circuit or cause leakage of confidential information from a system necessitates the detection of such subcircuits followed by their masking if possible. We suggest a method of finding a set of sequential circuit nodes in which Trojan Circuits can be inserted. The method is based on random estimations of controllability and observability of combinational nodes calculated using a description of sequential circuit working area and an evidence of existence of a transfer sequence for the proper set of internal states without finding the sequence itself. The method allows cutting calculations using operations on Reduced Ordered Binary Decision Diagrams (ROBDDs) that can depend only on the state variables of the circuit. The approach, unlike traditional ones, does not require preliminary sequential circuit simulation but can use its results. It can be used when malicious circuits cannot be detected during sequential circuit verification.

  6. Reliability of a computer-aided detection system in detecting lung metastases compared to manual palpation during surgery.

    Schramm, Alexandra; Wormanns, Dag; Leschber, Gunda; Merk, Johannes


    For resection of lung metastases computed tomography (CT) is needed to determine the operative strategy. A computer-aided detection (CAD) system, a software tool for automated detection of lung nodules, analyses the CT scans in addition to the radiologists and clearly marks lesions. The aim of this feasibility study was to evaluate the reliability of CAD in detecting lung metastases. Preoperative CT scans of 18 patients, who underwent surgery for suspected lung metastases, were analysed with CAD (September-December 2009). During surgery all suspected lesions were traced and resected. Histological examination was performed and results compared to radiologically suspicious nodes. Radiological analysis assisted by CAD detected 64 nodules (mean 3.6, range 1-7). During surgery 91 nodules (mean 5.0, range 1-11) were resected, resulting in 27 additionally palpated nodules. Histologically all these additional nodules were benign. In contrast, all 30 nodules shown to be metastases by histological studies were correctly described by CAD. The CAD system is a sensible and useful tool for finding pulmonary lesions. It detects more and smaller lesions than conventional radiological analysis. In this feasibility study we were able to show a greater reliability of the CAD analysis. A further and prospective study to confirm these data is ongoing.

  7. LED system reliability

    Driel, W.D. van; Yuan, C.A.; Koh, S.; Zhang, G.Q.


    This paper presents our effort to predict the system reliability of Solid State Lighting (SSL) applications. A SSL system is composed of a LED engine with micro-electronic driver(s) that supplies power to the optic design. Knowledge of system level reliability is not only a challenging scientific ex

  8. Measurement System Reliability Assessment

    Kłos Ryszard


    Full Text Available Decision-making in problem situations is based on up-to-date and reliable information. A great deal of information is subject to rapid changes, hence it may be outdated or manipulated and enforce erroneous decisions. It is crucial to have the possibility to assess the obtained information. In order to ensure its reliability it is best to obtain it with an own measurement process. In such a case, conducting assessment of measurement system reliability seems to be crucial. The article describes general approach to assessing reliability of measurement systems.

  9. Hawaii Electric System Reliability

    Loose, Verne William [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Silva Monroy, Cesar Augusto [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)


    This report addresses Hawaii electric system reliability issues; greater emphasis is placed on short-term reliability but resource adequacy is reviewed in reference to electric consumers’ views of reliability “worth” and the reserve capacity required to deliver that value. The report begins with a description of the Hawaii electric system to the extent permitted by publicly available data. Electrical engineering literature in the area of electric reliability is researched and briefly reviewed. North American Electric Reliability Corporation standards and measures for generation and transmission are reviewed and identified as to their appropriateness for various portions of the electric grid and for application in Hawaii. Analysis of frequency data supplied by the State of Hawaii Public Utilities Commission is presented together with comparison and contrast of performance of each of the systems for two years, 2010 and 2011. Literature tracing the development of reliability economics is reviewed and referenced. A method is explained for integrating system cost with outage cost to determine the optimal resource adequacy given customers’ views of the value contributed by reliable electric supply. The report concludes with findings and recommendations for reliability in the State of Hawaii.

  10. Hawaii electric system reliability.

    Silva Monroy, Cesar Augusto; Loose, Verne William


    This report addresses Hawaii electric system reliability issues; greater emphasis is placed on short-term reliability but resource adequacy is reviewed in reference to electric consumers' views of reliability %E2%80%9Cworth%E2%80%9D and the reserve capacity required to deliver that value. The report begins with a description of the Hawaii electric system to the extent permitted by publicly available data. Electrical engineering literature in the area of electric reliability is researched and briefly reviewed. North American Electric Reliability Corporation standards and measures for generation and transmission are reviewed and identified as to their appropriateness for various portions of the electric grid and for application in Hawaii. Analysis of frequency data supplied by the State of Hawaii Public Utilities Commission is presented together with comparison and contrast of performance of each of the systems for two years, 2010 and 2011. Literature tracing the development of reliability economics is reviewed and referenced. A method is explained for integrating system cost with outage cost to determine the optimal resource adequacy given customers' views of the value contributed by reliable electric supply. The report concludes with findings and recommendations for reliability in the State of Hawaii.

  11. Reliable fault detection and diagnosis of photovoltaic systems based on statistical monitoring approaches

    Harrou, Fouzi


    This study reports the development of an innovative fault detection and diagnosis scheme to monitor the direct current (DC) side of photovoltaic (PV) systems. Towards this end, we propose a statistical approach that exploits the advantages of one-diode model and those of the univariate and multivariate exponentially weighted moving average (EWMA) charts to better detect faults. Specifically, we generate array\\'s residuals of current, voltage and power using measured temperature and irradiance. These residuals capture the difference between the measurements and the predictions MPP for the current, voltage and power from the one-diode model, and use them as fault indicators. Then, we apply the multivariate EWMA (MEWMA) monitoring chart to the residuals to detect faults. However, a MEWMA scheme cannot identify the type of fault. Once a fault is detected in MEWMA chart, the univariate EWMA chart based on current and voltage indicators is used to identify the type of fault (e.g., short-circuit, open-circuit and shading faults). We applied this strategy to real data from the grid-connected PV system installed at the Renewable Energy Development Center, Algeria. Results show the capacity of the proposed strategy to monitors the DC side of PV systems and detects partial shading.

  12. Photovoltaic system reliability

    Maish, A.B.; Atcitty, C. [Sandia National Labs., NM (United States); Greenberg, D. [Ascension Technology, Inc., Lincoln Center, MA (United States)] [and others


    This paper discusses the reliability of several photovoltaic projects including SMUD`s PV Pioneer project, various projects monitored by Ascension Technology, and the Colorado Parks project. System times-to-failure range from 1 to 16 years, and maintenance costs range from 1 to 16 cents per kilowatt-hour. Factors contributing to the reliability of these systems are discussed, and practices are recommended that can be applied to future projects. This paper also discusses the methodology used to collect and analyze PV system reliability data.

  13. Multidisciplinary System Reliability Analysis

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


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

  14. System Reliability Analysis: Foundations.


    performance formulas for systems subject to pre- ventive maintenance are given. V * ~, , 9 D -2 SYSTEM RELIABILITY ANALYSIS: FOUNDATIONS Richard E...reliability in this case is V P{s can communicate with the terminal t = h(p) Sp2(((((p p)p) p)p)gp) + p(l -p)(((pL p)p)(p 2 JLp)) + p(l -p)((p(p p...For undirected networks, the basic reference is A. Satyanarayana and Kevin Wood (1982). For directed networks, the basic reference is Avinash

  15. Expert system aids reliability

    Johnson, A.T. [Tennessee Gas Pipeline, Houston, TX (United States)


    Quality and Reliability are key requirements in the energy transmission industry. Tennessee Gas Co. a division of El Paso Energy, has applied Gensym`s G2, object-oriented Expert System programming language as a standard tool for maintaining and improving quality and reliability in pipeline operation. Tennessee created a small team of gas controllers and engineers to develop a Proactive Controller`s Assistant (ProCA) that provides recommendations for operating the pipeline more efficiently, reliably and safely. The controller`s pipeline operating knowledge is recreated in G2 in the form of Rules and Procedures in ProCA. Two G2 programmers supporting the Gas Control Room add information to the ProCA knowledge base daily. The result is a dynamic, constantly improving system that not only supports the pipeline controllers in their operations, but also the measurement and communications departments` requests for special studies. The Proactive Controller`s Assistant development focus is in the following areas: Alarm Management; Pipeline Efficiency; Reliability; Fuel Efficiency; and Controller Development.

  16. Load Control System Reliability

    Trudnowski, Daniel [Montana Tech of the Univ. of Montana, Butte, MT (United States)


    This report summarizes the results of the Load Control System Reliability project (DOE Award DE-FC26-06NT42750). The original grant was awarded to Montana Tech April 2006. Follow-on DOE awards and expansions to the project scope occurred August 2007, January 2009, April 2011, and April 2013. In addition to the DOE monies, the project also consisted of matching funds from the states of Montana and Wyoming. Project participants included Montana Tech; the University of Wyoming; Montana State University; NorthWestern Energy, Inc., and MSE. Research focused on two areas: real-time power-system load control methodologies; and, power-system measurement-based stability-assessment operation and control tools. The majority of effort was focused on area 2. Results from the research includes: development of fundamental power-system dynamic concepts, control schemes, and signal-processing algorithms; many papers (including two prize papers) in leading journals and conferences and leadership of IEEE activities; one patent; participation in major actual-system testing in the western North American power system; prototype power-system operation and control software installed and tested at three major North American control centers; and, the incubation of a new commercial-grade operation and control software tool. Work under this grant certainly supported the DOE-OE goals in the area of “Real Time Grid Reliability Management.”

  17. Reliable Grid Condition Detection and Control of Single-Phase Distributed Power Generation Systems

    Ciobotaru, Mihai

    The constant growth of Distributed Power Generation Systems (DPGS) presents an efficient and economic way of generating electricity closer to the load(s). The DPGS can contribute to an efficient and renewable electricity future by potentially: increasing the use of renewable sources of energy......; improving the efficiency of the electricity system by reducing transmission and distribution losses; improving the security of the electricity supply through increased diversity of supply and reduced vulnerability to simultaneous system failures. However, the new trend of using DPGS comes also with a suite...... of new challenges. One of the challenges is the interaction between the DPGS and the utility grid. As a consequence, grid interconnection requirements applying to distributed generation are continuously updated in order to maintain the quality and the stability of the utility grid. The new upcoming...

  18. Ultimately Reliable Pyrotechnic Systems

    Scott, John H.; Hinkel, Todd


    This paper presents the methods by which NASA has designed, built, tested, and certified pyrotechnic devices for high reliability operation in extreme environments and illustrates the potential applications in the oil and gas industry. NASA's extremely successful application of pyrotechnics is built upon documented procedures and test methods that have been maintained and developed since the Apollo Program. Standards are managed and rigorously enforced for performance margins, redundancy, lot sampling, and personnel safety. The pyrotechnics utilized in spacecraft include such devices as small initiators and detonators with the power of a shotgun shell, detonating cord systems for explosive energy transfer across many feet, precision linear shaped charges for breaking structural membranes, and booster charges to actuate valves and pistons. NASA's pyrotechnics program is one of the more successful in the history of Human Spaceflight. No pyrotechnic device developed in accordance with NASA's Human Spaceflight standards has ever failed in flight use. NASA's pyrotechnic initiators work reliably in temperatures as low as -420 F. Each of the 135 Space Shuttle flights fired 102 of these initiators, some setting off multiple pyrotechnic devices, with never a failure. The recent landing on Mars of the Opportunity rover fired 174 of NASA's pyrotechnic initiators to complete the famous '7 minutes of terror.' Even after traveling through extreme radiation and thermal environments on the way to Mars, every one of them worked. These initiators have fired on the surface of Titan. NASA's design controls, procedures, and processes produce the most reliable pyrotechnics in the world. Application of pyrotechnics designed and procured in this manner could enable the energy industry's emergency equipment, such as shutoff valves and deep-sea blowout preventers, to be left in place for years in extreme environments and still be relied upon to function when needed, thus greatly enhancing

  19. The validity and reliability of the System for Early Detection of Developmental Disorders: 3-36 months

    Francisco Alcantud Marín


    Full Text Available This article introduces the System for Early Detection of Developmental Disorders (referred to as SDPTD for its abbreviation in Spanish, a system developed in previous papers. The SDPTD is a developmental screening test that includes seven questionnaires, one for each cutoff of age (3, 6, 9, 12, 18, 24 and 36 months. These questionnaires have been designed to be answered by parents. To study its validity, SDPTD was administered to a sample of 728 children (approximately 100 children in each of the seven cutoff age groups. A development scale known as Merrill-Palmer-Revised (MP-R was used as a criteria test. The development state of the children was tested again one year later. The results show a high level of agreement between parents and professionals. The concurrent validity is high although it varies by cutoff age. Regarding the diagnostic validity a year after the original evaluation, levels of sensitivity and specificity are high enough to consider the system reliable, valid and suitable for screening purposes.

  20. Innovations in power systems reliability

    Santora, Albert H; Vaccaro, Alfredo


    Electrical grids are among the world's most reliable systems, yet they still face a host of issues, from aging infrastructure to questions of resource distribution. Here is a comprehensive and systematic approach to tackling these contemporary challenges.

  1. Reliability Management for Information System

    李睿; 俞涛; 刘明伦


    An integrated intelligent management is presented to help organizations manage many heterogeneous resources in their information system. A general architecture of management for information system reliability is proposed, and the architecture from two aspects, process model and hierarchical model, described. Data mining techniques are used in data analysis. A data analysis system applicable to real-time data analysis is developed by improved data mining on the critical processes. The framework of the integrated management for information system reliability based on real-time data mining is illustrated, and the development of integrated and intelligent management of information system discussed.

  2. On Bayesian System Reliability Analysis

    Soerensen Ringi, M.


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

  3. On the reliability of fire detection and alarm systems. Exploration and analysis of data from nuclear and non-nuclear installations

    Nyyssoenen, T.; Rajakko, J.; Keski-Rahkonen, O. [VTT Building and Transport, Espoo (Finland)


    A literature review of reliability data of fire detection and alarm systems was made resulting to rough estimates of some failure frequencies. No theoretical or technical articles on the structure of reliability models of these installations were found. Inspection records of fire detection and alarm system installations by SPEK were studied, and transferred in electronic data base classifying observed failures in failure modes (59) and severity categories (3) guided by freely written records in the original data. The results of that work are presented without many comments in tabular form in this paper. A small sample of installations was collected, and number of components in them was counted to derive some distributions for determination of national populations of various components based on know total amount of installations. From NPPs (Loviisa, Olkiluoto and Barsebaeck) failure reports were analysed, and observed failures of fire detection and alarm systems were classified by severity and detection mode. They are presented here in tabular form for the original and new addressable systems. Populations were counted individually, but for all installations needed documents were not available. Therefore, presented failure frequencies are just first estimates, which will be refined later. (orig.)

  4. Component reliability for electronic systems

    Bajenescu, Titu-Marius I


    The main reason for the premature breakdown of today's electronic products (computers, cars, tools, appliances, etc.) is the failure of the components used to build these products. Today professionals are looking for effective ways to minimize the degradation of electronic components to help ensure longer-lasting, more technically sound products and systems. This practical book offers engineers specific guidance on how to design more reliable components and build more reliable electronic systems. Professionals learn how to optimize a virtual component prototype, accurately monitor product reliability during the entire production process, and add the burn-in and selection procedures that are the most appropriate for the intended applications. Moreover, the book helps system designers ensure that all components are correctly applied, margins are adequate, wear-out failure modes are prevented during the expected duration of life, and system interfaces cannot lead to failure.

  5. a Reliability Evaluation System of Association Rules

    Chen, Jiangping; Feng, Wanshu; Luo, Minghai


    In mining association rules, the evaluation of the rules is a highly important work because it directly affects the usability and applicability of the output results of mining. In this paper, the concept of reliability was imported into the association rule evaluation. The reliability of association rules was defined as the accordance degree that reflects the rules of the mining data set. Such degree contains three levels of measurement, namely, accuracy, completeness, and consistency of rules. To show its effectiveness, the "accuracy-completeness-consistency" reliability evaluation system was applied to two extremely different data sets, namely, a basket simulation data set and a multi-source lightning data fusion. Results show that the reliability evaluation system works well in both simulation data set and the actual problem. The three-dimensional reliability evaluation can effectively detect the useless rules to be screened out and add the missing rules thereby improving the reliability of mining results. Furthermore, the proposed reliability evaluation system is applicable to many research fields; using the system in the analysis can facilitate obtainment of more accurate, complete, and consistent association rules.

  6. Defining Requirements for Improved Photovoltaic System Reliability

    Maish, A.B.


    Reliable systems are an essential ingredient of any technology progressing toward commercial maturity and large-scale deployment. This paper defines reliability as meeting system fictional requirements, and then develops a framework to understand and quantify photovoltaic system reliability based on initial and ongoing costs and system value. The core elements necessary to achieve reliable PV systems are reviewed. These include appropriate system design, satisfactory component reliability, and proper installation and servicing. Reliability status, key issues, and present needs in system reliability are summarized for four application sectors.

  7. Assessment of Interpersonal Motivation in Transcripts (AIMIT): an inter- and intra-rater reliability study of a new method of detection of interpersonal motivational systems in psychotherapy.

    Fassone, G; Valcella, F; Pallini, S; Scarcella, F; Tombolini, L; Ivaldi, A; Prunetti, E; Manaresi, F; Liotti, G


    Assessing Interpersonal Motivations in Transcripts (AIMIT) is a coding system aiming to systematically detect the activity of interpersonal motivational systems (IMS) in the therapeutic dialogue. An inter- and intra-rater reliability study has been conducted. Sixteen video-recorded psychotherapy sessions were selected and transcribed according to the AIMIT criteria. Sessions relate to 16 patients with an Axis II diagnosis, with a mean Global Assessment of Functioning of 51. For the intra-rater reliability evaluation, five sessions have been selected and assigned to five independent coders who where asked to make a first evaluation, and then a second independent one 14 days later. For the inter-rater reliability study, the sessions coded by the therapist-coder were jointly revised with another coder and finally classified as gold standard. The 16 standard sessions were sent to other evaluators for the independent coding. The agreement (κ) was estimated according to the following parameters for each coding unit: evaluation units supported by the 'codable' activation of one or more IMS; motivational interaction with reference to the ongoing relation between patient and therapist; an interaction between the patient and another person reported/narrated by the patient; detection of specific IMS: attachment (At), caregiving (CG), rank (Ra), sexuality (Se), peer cooperation (PC); and transitions from one IMS to another were also scored. The intra-rater agreement was evaluated through the parameters 'cod', 'At', 'CG', 'Ra', 'Se' and 'PC' described above. A total of 2443 coding units were analysed. For the nine parameters on which the agreement was calculated, eight ['coded (Cod)', 'ongoing relation (Rel)', 'narrated relation (Nar)', 'At', 'CG', 'Ra', 'Se' and 'PC'] have κ values comprised between 0.62 (CG) and 0.81 (Cod) and were therefore satisfactory. The scoring of 'transitions' showed agreement values slightly below desired cut-off (0.56). Intra-rater reliability was

  8. System Reliability for Offshore Wind Turbines

    Marquez-Dominguez, Sergio; Sørensen, John Dalsgaard


    are considered for reliability verification according to international design standards of OWTs. System effects become important for each substructure with many potential fatigue hot spots. Therefore, in this paper a framework for system effects is presented. This information can be e.g. no detection of cracks......E). In consequence, a rational treatment of uncertainties is done in order to assess the reliability of critical details in OWTs. Limit state equations are formulated for fatigue critical details which are not influenced by wake effects generated in offshore wind farms. Furthermore, typical bi-linear S-N curves...... in inspections or measurements from condition monitoring systems. Finally, an example is established to illustrate the practical application of this framework for jacket type wind turbine substructure considering system effects....

  9. Reliability of Power Electronic Converter Systems

    -link capacitance in power electronic converter systems; wind turbine systems; smart control strategies for improved reliability of power electronics system; lifetime modelling; power module lifetime test and state monitoring; tools for performance and reliability analysis of power electronics systems; fault......-tolerant adjustable speed drive systems; mission profile oriented reliability design in wind turbine and photovoltaic systems; reliability of power conversion systems in photovoltaic applications; power supplies for computers; and high-power converters. Reliability of Power Electronic Converter Systems is essential...... reading for researchers, professionals and students working with power electronics and their applications, particularly those specializing in the development and application of power electronic converters and systems....

  10. Fault tolerant highly reliable inertial navigation system

    Jeerage, Mahesh; Boettcher, Kevin

    This paper describes a development of failure detection and isolation (FDI) strategies for highly reliable inertial navigation systems. FDI strategies are developed based on the generalized likelihood ratio test (GLRT). A relationship between detection threshold and false alarm rate is developed in terms of the sensor parameters. A new method for correct isolation of failed sensors is presented. Evaluation of FDI performance parameters, such as false alarm rate, wrong isolation probability, and correct isolation probability, are presented. Finally a fault recovery scheme capable of correcting false isolation of good sensors is presented.

  11. System Reliability of Timber Structures

    Kirkegaard, Poul Henning; Sørensen, John Dalsgaard


    For reduction of the risk of collapse in the event of loss of structural element(s), a structural engineer may take necessary steps to design a collapse-resistant structure that is insensitive to accidental circumstances e.g. by incorporating characteristics like redundancy, ties, ductility, key ...... elements, alternate load path(s) etc. in the structural design. In general these characteristics can have a positive influence on system reliability of a structure however, in Eurocodes ductility is only awarded for concrete and steel structures but not for timber structures. It is well......-know that structural systems can redistribute internal forces due to ductility of a connection, i.e. some additional loads can be carried by the structure. The same effect is also possible for reinforced concrete structures and structures of steel. However, for timber structures codes do not award that ductility...

  12. Demonstration Study for Reliability Assessment of SHM Systems Incorporating Model-Assisted Probability of Detection Approach (Preprint)


    02.50.-r, 81.70.-q INTRODUCTION The successful deployment of systems for health monitoring of structures depends on appropriate verification... magnetostrictive actuator was used for band-limited pseudo-random excitation up to 1200 Hz, and the dynamic response of the plate was recorded using eight

  13. Reliability analysis of an associated system

    陈长杰; 魏一鸣; 蔡嗣经


    Based on engineering reliability of large complex system and distinct characteristic of soft system, some new conception and theory on the medium elements and the associated system are created. At the same time, the reliability logic model of associated system is provided. In this paper, through the field investigation of the trial operation, the engineering reliability of the paste fill system in No.2 mine of Jinchuan Non-ferrous Metallic Corporation is analyzed by using the theory of associated system.

  14. 75 FR 71625 - System Restoration Reliability Standards


    ... Energy Regulatory Commission 18 CFR Part 40 System Restoration Reliability Standards November 18, 2010... to approve Reliability Standards EOP-001-1 (Emergency Operations Planning), EOP- 005-2 (System... modifications to proposed EOP-005-2 and EOP-006-2. The proposed Reliability Standards require that...

  15. Multi-Agent System for Resource Reliability


    1 research and development of a prototype for network resource reliability has laid the groundwork for the Phase 2 implementation of MASRR, a Multi - Agent System for Resource Reliability, and its eventual commercialization.

  16. Advances in reliability and system engineering

    Davim, J


    This book presents original studies describing the latest research and developments in the area of reliability and systems engineering. It helps the reader identifying gaps in the current knowledge and presents fruitful areas for further research in the field. Among others, this book covers reliability measures, reliability assessment of multi-state systems, optimization of multi-state systems, continuous multi-state systems, new computational techniques applied to multi-state systems and probabilistic and non-probabilistic safety assessment.

  17. Probability of detection (POD) is not NDT/E reliability

    Rummel, Ward D.


    The reliability of nondestructive testing procedures has been a primary consideration in the development, application and advancement of nondestructive testing (NDT/E) technology. Indeed significant advancements have been made in process control of procedures and in training, qualification personnel who apply NDT procedures. Recognition and the demand for NDT increased with successes. NDT was integrated into engineering practices and technologies. The design, operation, maintenance, life cycle and risk analyses changed dramatically with the development, application and incorporation of fracture mechanics in engineering requirements, engineering practices and engineering systems management. Those engineering changes increased demands and a revolution in NDT requirements, practices and technology advancement. The Probability of Detection (POD) metric was developed to provide a quantitative assessment of NDT detection capabilities and was focused on the smallest reliably detectable flaw. Critical needs for application resulted in wide acceptance of POD as a metric to quantify the detection capability of NDT procedures. Unfortunately, POD is often misinterpreted as a primary measure of the reliability of NDT procedures. This paper addresses the nature of POD and requirements for assessment and application. Emphasis is on evolution of a new branch in NDT engineering, technology application and validation.

  18. Quality and Reliability of Missile System

    Mr. Prahlada


    Full Text Available Missile system is a single-shot weapon system which requires very high quality and reliability. Therefore, quality and reliability have to be built into the system from designing to testing and evaluation. In this paper, the technological challenges encountered during development of operational missile system and the factors considered to build quality and reliability through the design, manufacture, assembly, testing and by sharing the knowledge with other aerospace agencies, industries and institutions, etc. have been presented.

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

    Denz, R; Vergara-Fernández, A


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

  20. On reliability optimization for power generation systems


    The reliability level of a power generation system is an important problem which is concerned by both electricity producers and electricity consumers. Why? It is known that the high reliability level may result in additional utility cost, and the low reliability level may result in additional consumer's cost, so the optimum reliability level should be determined such that the total cost can reach its minimum. Four optimization models for power generation system reliability are constructed, and the proven efficient solutions for these models are also given.

  1. Good interrater reliability of a new grading system in detecting traumatic bone marrow lesions in the knee by dual energy CT virtual non-calcium images

    Cao, Jian-xin; Wang, Yi-min [Department of Radiology, Wuhan 161th Hospital, 68 Huangpu Road, Wuhan 430010 (China); Kong, Xiang-quan, E-mail: [Department of Radiology, Union Hospital Affiliated to Tongji Medical College, Huazhong University of Science and Technology, 1277 Jiefang Avenue, Wuhan 430022 (China); Yang, Cheng; Wang, Peng [Department of Radiology, Wuhan 161th Hospital, 68 Huangpu Road, Wuhan 430010 (China)


    upper end of the tibia were 91.0%, 100.0%, 100.0%, and 95.4%, respectively. The CT values of bone marrow were (−52.5 ± 31.3) HU in positive area and (−91.2 ± 16.9) HU in negative area for the lower end of the femur, and those were (−51.3 ± 30.2) HU in positive area and (−104.7 ± 17.5) HU in negative area for the upper end of the tibia (all p values < 0.0001). The areas under the ROC curve of VNCa images for detection of BMLs were 0.875 for the lower end of the femur and 0.939 for the upper end of the tibia. Conclusion: Good interrater reliability of this new grading system in detecting traumatic BMLs in the knee by VNCa images of DECT can be obtained with good diagnostic predictive values.

  2. Exact reliability quantification of highly reliable systems with maintenance

    Bris, Radim, E-mail: radim.bris@vsb.c [VSB-Technical University Ostrava, Faculty of Electrical Engineering and Computer Science, Department of Applied Mathematics, 17. listopadu 15, 70833 Ostrava-Poruba (Czech Republic)


    When a system is composed of highly reliable elements, exact reliability quantification may be problematic, because computer accuracy is limited. Inaccuracy can be due to different aspects. For example, an error may be made when subtracting two numbers that are very close to each other, or at the process of summation of many very different numbers, etc. The basic objective of this paper is to find a procedure, which eliminates errors made by PC when calculations close to an error limit are executed. Highly reliable system is represented by the use of directed acyclic graph which is composed from terminal nodes, i.e. highly reliable input elements, internal nodes representing subsystems and edges that bind all of these nodes. Three admissible unavailability models of terminal nodes are introduced, including both corrective and preventive maintenance. The algorithm for exact unavailability calculation of terminal nodes is based on merits of a high-performance language for technical computing MATLAB. System unavailability quantification procedure applied to a graph structure, which considers both independent and dependent (i.e. repeatedly occurring) terminal nodes is based on combinatorial principle. This principle requires summation of a lot of very different non-negative numbers, which may be a source of an inaccuracy. That is why another algorithm for exact summation of such numbers is designed in the paper. The summation procedure uses benefits from a special number system with the base represented by the value 2{sup 32}. Computational efficiency of the new computing methodology is compared with advanced simulation software. Various calculations on systems from references are performed to emphasize merits of the methodology.

  3. Towards Reliable Integrated Services for Dependable Systems

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


    Reliability issues for various technical systems are discussed and focus is directed towards distributed systems, where communication facilities are vital to maintain system functionality. Reliability in communication subsystems is considered as a resource to be shared among a number of logical...

  4. Towards Reliable Integrated Services for Dependable Systems

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

    Reliability issues for various technical systems are discussed and focus is directed towards distributed systems, where communication facilities are vital to maintain system functionality. Reliability in communication subsystems is considered as a resource to be shared among a number of logical...

  5. Solid State Lighting Reliability Components to Systems

    Fan, XJ


    Solid State Lighting Reliability: Components to Systems begins with an explanation of the major benefits of solid state lighting (SSL) when compared to conventional lighting systems including but not limited to long useful lifetimes of 50,000 (or more) hours and high efficacy. When designing effective devices that take advantage of SSL capabilities the reliability of internal components (optics, drive electronics, controls, thermal design) take on critical importance. As such a detailed discussion of reliability from performance at the device level to sub components is included as well as the integrated systems of SSL modules, lamps and luminaires including various failure modes, reliability testing and reliability performance. This book also: Covers the essential reliability theories and practices for current and future development of Solid State Lighting components and systems Provides a systematic overview for not only the state-of-the-art, but also future roadmap and perspectives of Solid State Lighting r...

  6. PV Systems Reliability Final Technical Report.

    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)


    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.

  7. Reliability of large and complex systems

    Kolowrocki, Krzysztof


    Reliability of Large and Complex Systems, previously titled Reliability of Large Systems, is an innovative guide to the current state and reliability of large and complex systems. In addition to revised and updated content on the complexity and safety of large and complex mechanisms, this new edition looks at the reliability of nanosystems, a key research topic in nanotechnology science. The author discusses the importance of safety investigation of critical infrastructures that have aged or have been exposed to varying operational conditions. This reference provides an asympt

  8. Bayesian Missile System Reliability from Point Estimates


    OCT 2014 2. REPORT TYPE N/A 3. DATES COVERED - 4. TITLE AND SUBTITLE Bayesian Missile System Reliability from Point Estimates 5a. CONTRACT...Principle (MEP) to convert point estimates to probability distributions to be used as priors for Bayesian reliability analysis of missile data, and...illustrate this approach by applying the priors to a Bayesian reliability model of a missile system. 15. SUBJECT TERMS priors, Bayesian , missile


    Popescu V.S.


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

  10. New Multiplexing Tools for Reliable GMO Detection

    Pla, M.; Nadal, A.; Baeten, V.; Bahrdt, C.; Berben, G.; Bertheau, Y.; Coll, A.; Dijk, van J.P.; Dobnik, D.; Fernandez-Pierna, J.A.; Gruden, K.; Hamels, S.; Holck, A.; Holst-Jensen, A.; Janssen, E.; Kok, E.J.; Paz, La J.L.; Laval, V.; Leimanis, S.; Malcevschi, A.; Marmiroli, N.; Morisset, D.; Prins, T.W.; Remacle, J.; Ujhelyi, G.; Wulff, D.


    Among the available methods for GMO detection, enforcement and routine laboratories use in practice PCR, based on the detection of transgenic DNA. The cost required for GMO analysis is constantly increasing due to the progress of GMO commercialization, with inclusion of higher diversity of species,

  11. Computer system reliability safety and usability

    Dhillon, BS


    Computer systems have become an important element of the world economy, with billions of dollars spent each year on development, manufacture, operation, and maintenance. Combining coverage of computer system reliability, safety, usability, and other related topics into a single volume, Computer System Reliability: Safety and Usability eliminates the need to consult many different and diverse sources in the hunt for the information required to design better computer systems.After presenting introductory aspects of computer system reliability such as safety, usability-related facts and figures,

  12. Design for Reliability of Power Electronic Systems

    Wang, Huai; Ma, Ke; Blaabjerg, Frede


    Advances in power electronics enable efficient and flexible processing of electric power in the application of renewable energy sources, electric vehicles, adjustable-speed drives, etc. More and more efforts are devoted to better power electronic systems in terms of reliability to ensure high...... on a 2.3 MW wind power converter is discussed with emphasis on the reliability critical components IGBTs. Different aspects of improving the reliability of the power converter are mapped. Finally, the challenges and opportunities to achieve more reliable power electronic systems are addressed....

  13. Reliability of power electronic converter systems

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


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

  14. Reliability Growth in Space Life Support Systems

    Jones, Harry W.


    A hardware system's failure rate often increases over time due to wear and aging, but not always. Some systems instead show reliability growth, a decreasing failure rate with time, due to effective failure analysis and remedial hardware upgrades. Reliability grows when failure causes are removed by improved design. A mathematical reliability growth model allows the reliability growth rate to be computed from the failure data. The space shuttle was extensively maintained, refurbished, and upgraded after each flight and it experienced significant reliability growth during its operational life. In contrast, the International Space Station (ISS) is much more difficult to maintain and upgrade and its failure rate has been constant over time. The ISS Carbon Dioxide Removal Assembly (CDRA) reliability has slightly decreased. Failures on ISS and with the ISS CDRA continue to be a challenge.

  15. Telecommunications system reliability engineering theory and practice

    Ayers, Mark L


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

  16. Sensitivity Analysis for the System Reliability Function


    reliabilities. The unique feature of the approach is that stunple data collected on K inde-ndent replications using a specified component reliability % v &:•r...Carlo method. The polynomial time algorithm of Agrawaw Pad Satyanarayana (104) fIr the exact reliability computaton for seres- allel systems exemplifies...consideration. As an example for the s-t connectedness problem, let denote -7- edge-disjoint minimal s-t paths of G and let V , denote edge-disjoint

  17. Specification for reliability data management system



    This document contains the objectives, scopes, a brief delineation of the design, performance, and definition of the Reliability Data Management System (RDMS). The General Electric Company - Fast Breeder Reactor Department (GE-FBRD) has responsibility for the design and implementation of a Reliability Data Management System (RDMS). This document describes and specifies the RDMS requirements. The RDMS is currently focused on obtaining data for the Clinch River Breeder Reactor Plant (CRBRP) Shutdown System and Shutdown Heat Removal System, but has been designed with capability and flexibility for accommodating additional CRBRP and Liquid Metal Fast Breeder Reactor (LMFBR) reliability data.

  18. A reliable method for detecting complexed DNA in vitro

    Holladay, C.; Keeney, M.; Newland, B.; Mathew, A.; Wang, W.; Pandit, A.


    Quantification of eluted nucleic acids is a critical parameter in characterizing biomaterial based gene-delivery systems. The most commonly used method is to assay samples with an intercalating fluorescent dye such as PicoGreen®. However, this technique was developed for unbound DNA and the current trend in gene delivery is to condense DNA with transfection reagents, which interfere with intercalation. Here, for the first time, the DNA was permanently labeled with the fluorescent dye Cy5 prior to complexation, an alternative technique hypothesized to allow quantification of both bound and unbound DNA. A comparison of the two methods was performed by quantifying the elution of six different varieties of DNA complexes from a model biomaterial (collagen) scaffold. After seven days of elution, the PicoGreen® assay only allowed detection of three types of complexes (those formed using Lipofectin™ and two synthesised copolymers). However, the Cy5 fluorescent labeling technique enabled detection of all six varieties including those formed via common transfection agents poly(ethylene imine), poly-l-lysine and SuperFect™. This allowed reliable quantification of the elution of all these complexes from the collagen scaffold. Thus, while intercalating dyes may be effective and reliable for detecting double-stranded, unbound DNA, the technique described in this work allowed reliable quantification of DNA independent of complexation state.Quantification of eluted nucleic acids is a critical parameter in characterizing biomaterial based gene-delivery systems. The most commonly used method is to assay samples with an intercalating fluorescent dye such as PicoGreen®. However, this technique was developed for unbound DNA and the current trend in gene delivery is to condense DNA with transfection reagents, which interfere with intercalation. Here, for the first time, the DNA was permanently labeled with the fluorescent dye Cy5 prior to complexation, an alternative technique

  19. Reliability Survey of Military Acquisition Systems


    software-intensive sensor and weapons systems, ensuring that there are no open Category 1 or 2 deficiency reports prior to OT. There is also evidence...reliability growth curve used to develop intermediate reliability goal(s)? 5c3 Are the reliability growth goal(s) linked to OTs (e.g., IOT &E, FOT&E...the reliability growth potential? 8 Did your program have an operational test in FY12? 8a What type of operational test was it? (DT/OT, OA/LUT, IOT &E

  20. Reliable detection of directional couplings using rank statistics.

    Chicharro, Daniel; Andrzejak, Ralph G


    To detect directional couplings from time series various measures based on distances in reconstructed state spaces were introduced. These measures can, however, be biased by asymmetries in the dynamics' structure, noise color, or noise level, which are ubiquitous in experimental signals. Using theoretical reasoning and results from model systems we identify the various sources of bias and show that most of them can be eliminated by an appropriate normalization. We furthermore diminish the remaining biases by introducing a measure based on ranks of distances. This rank-based measure outperforms existing distance-based measures concerning both sensitivity and specificity for directional couplings. Therefore, our findings are relevant for a reliable detection of directional couplings from experimental signals.

  1. System Reliability Assessment of Offshore Pipelines

    Mustaffa, Z.


    The title of this thesis, System Reliability Assessment of Offshore Pipelines, portrays the application of probabilistic methods in assessing the reliability of these structures. The main intention of this thesis is to identify, apply and judge the suitability of the probabilistic methods in evalua

  2. Reliability Based Optimization of Structural Systems

    Sørensen, John Dalsgaard


    The optimization problem to design structural systems such that the reliability is satisfactory during the whole lifetime of the structure is considered in this paper. Some of the quantities modelling the loads and the strength of the structure are modelled as random variables. The reliability...

  3. Reliable computer systems design and evaluatuion

    Siewiorek, Daniel


    Enhance your hardware/software reliabilityEnhancement of system reliability has been a major concern of computer users and designers ¦ and this major revision of the 1982 classic meets users' continuing need for practical information on this pressing topic. Included are case studies of reliablesystems from manufacturers such as Tandem, Stratus, IBM, and Digital, as well as coverage of special systems such as the Galileo Orbiter fault protection system and AT&T telephone switching processors.

  4. Reliability assessment of continuous mining technological systems


    Article is devoted to the analysis of reliability of parameters of continuous system of extraction with use of various approaches with the purpose of performance of a fast estimation of general efficiency of the equipment of such industrial systems, as Monte-Carlo and stress-force of intervention. Article is devoted to the analysis of reliability of parameters of continuous system of extraction with use of various approaches with the purpose of performance of a fast estimation of general e...

  5. Production Facility System Reliability Analysis Report

    Dale, Crystal Buchanan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Klein, Steven Karl [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)


    This document describes the reliability, maintainability, and availability (RMA) modeling of the Los Alamos National Laboratory (LANL) design for the Closed Loop Helium Cooling System (CLHCS) planned for the NorthStar accelerator-based 99Mo production facility. The current analysis incorporates a conceptual helium recovery system, beam diagnostics, and prototype control system into the reliability analysis. The results from the 1000 hr blower test are addressed.

  6. Multi-Disciplinary System Reliability Analysis

    Mahadevan, Sankaran; Han, Song


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

  7. Reliably Detectable Flaw Size for NDE Methods that Use Calibration

    Koshti, Ajay M.


    Probability of detection (POD) analysis is used in assessing reliably detectable flaw size in nondestructive evaluation (NDE). MIL-HDBK-1823 and associated mh1823 POD software gives most common methods of POD analysis. In this paper, POD analysis is applied to an NDE method, such as eddy current testing, where calibration is used. NDE calibration standards have known size artificial flaws such as electro-discharge machined (EDM) notches and flat bottom hole (FBH) reflectors which are used to set instrument sensitivity for detection of real flaws. Real flaws such as cracks and crack-like flaws are desired to be detected using these NDE methods. A reliably detectable crack size is required for safe life analysis of fracture critical parts. Therefore, it is important to correlate signal responses from real flaws with signal responses form artificial flaws used in calibration process to determine reliably detectable flaw size.

  8. A Reliability-Based Multi-Algorithm Fusion Technique in Detecting Changes in Land Cover

    Jiangping Chen


    Full Text Available Detecting land use or land cover changes is a challenging problem in analyzing images. Change-detection plays a fundamental role in most of land use or cover monitoring systems using remote-sensing techniques. The reliability of individual automatic change-detection algorithms is currently below operating requirements when considering the intrinsic uncertainty of a change-detection algorithm and the complexity of detecting changes in remote-sensing images. In particular, most of these algorithms are only suited for a specific image data source, study area and research purpose. Only a number of comprehensive change-detection methods that consider the reliability of the algorithm in different implementation situations have been reported. This study attempts to explore the advantages of combining several typical change-detection algorithms. This combination is specifically designed for a highly reliable change-detection task. Specifically, a fusion approach based on reliability is proposed for an exclusive land use or land cover change-detection. First, the reliability of each candidate algorithm is evaluated. Then, a fuzzy comprehensive evaluation is used to generate a reliable change-detection approach. This evaluation is a transformation between a one-way evaluation matrix and a weight vector computed using the reliability of each candidate algorithm. Experimental results reveal that the advantages of combining these distinct change-detection techniques are evident.

  9. Operational reliability of standby safety systems

    Grant, G.M.; Atwood, C.L.; Gentillon, C.D. [Idaho National Engineering Lab., Idaho Falls, ID (United States)] [and others


    The Idaho National Engineering Laboratory (INEL) is evaluating the operational reliability of several risk-significant standby safety systems based on the operating experience at US commercial nuclear power plants from 1987 through 1993. The reliability assessed is the probability that the system will perform its Probabilistic Risk Assessment (PRA) defined safety function. The quantitative estimates of system reliability are expected to be useful in risk-based regulation. This paper is an overview of the analysis methods and the results of the high pressure coolant injection (HPCI) system reliability study. Key characteristics include (1) descriptions of the data collection and analysis methods, (2) the statistical methods employed to estimate operational unreliability, (3) a description of how the operational unreliability estimates were compared with typical PRA results, both overall and for each dominant failure mode, and (4) a summary of results of the study.

  10. Reliability of microtechnology interconnects, devices and systems

    Liu, Johan; Sarkka, Jussi; Tegehall, Per-Erik; Andersson, Cristina


    This text discusses the reliability of microtechnology products from the bottom up, beginning with devices and extending to systems. It covers many topics, and it addresses specific failure modes in solder and conductive adhesives at great length.


    A. Stepanov


    Full Text Available The ways of increasing of exploitation reliability of dump trucks with the aim of increasing of effectiveness of exploitation of transportation systems of rock heaps at coal mines.

  12. 3D face recognition algorithm based on detecting reliable components

    Huang Wenjun; Zhou Xuebing; Niu Xiamu


    Fisherfaces algorithm is a popular method for face recognition. However, there exist some unstable components that degrade recognition performance. In this paper, we propose a method based on detecting reliable components to overcome the problem and introduce it to 3D face recognition. The reliable components are detected within the binary feature vector, which is generated from the Fisherfaces feature vector based on statistical properties, and is used for 3D face recognition as the final feature vector. Experimental results show that the reliable components feature vector is much more effective than the Fisherfaces feature vector for face recognition.

  13. Reliable Fluid Power Pitch Systems

    Liniger, Jesper; Pedersen, Henrik Clemmensen; Soltani, Mohsen


    The key objectives of wind turbine manufactures and buyers are to reduce the Total Cost of Ownership and Total Cost of Energy. Among others, low downtime of a wind turbine is important to increase the amount of energy produced during its lifetime. Historical data indicate that pitch systems...

  14. Reliability and diagnostic of modular systems

    J. Kohlas


    Full Text Available Reliability and diagnostic are in general two problems discussed separately. Yet the two problems are in fact closely related to each other. Here, this relation is considered in the simple case of modular systems. We show, how the computation of reliability and diagnostic can efficiently be done within the same Bayesian network induced by the modularity of the structure function of the system.

  15. Reliability of Naval Radar Systems


    CONFIDENTIAL (THIS PACE IS UNCUIASSFIED) CONFIDENTIAL (U) For airborne radars, 3-M’(Maintenance and Material Management )and RISE (Readiness Improvement...of the 3-M Program reports (3-M from Maintenance and Material Management ) as well as Naval Air Systems Command RISE (Readi-. ness Improvement Summary...TRANSIT PULSE LE11CTR (;As): 12.8 ANTENNA UEIGHr (k 1058 (2331 lbs.) excluding pedestal COMPRESSED PLUE LENGTH (.is): 0.2 BEAN POSITIObiNG TECNIQUES : H)RZ

  16. Demand Response For Power System Reliability: FAQ

    Kirby, Brendan J [ORNL


    Demand response is the most underutilized power system reliability resource in North America. Technological advances now make it possible to tap this resource to both reduce costs and improve. Misconceptions concerning response capabilities tend to force loads to provide responses that they are less able to provide and often prohibit them from providing the most valuable reliability services. Fortunately this is beginning to change with some ISOs making more extensive use of load response. This report is structured as a series of short questions and answers that address load response capabilities and power system reliability needs. Its objective is to further the use of responsive load as a bulk power system reliability resource in providing the fastest and most valuable ancillary services.

  17. Reliability of photovoltaic systems: A field report

    Thomas, M. G.; Fuentes, M. K.; Lashway, C.; Black, B. D.

    Performance studies and field measurements of photovoltaic systems indicate a 1 to 2% per year degradation in array energy production. The cause for much of the degradation has been identified as soiling, failed modules, and failures in interconnections. System performance evaluation continues to be complicated by the poor reliability of some power conditioning hardware that has greatly diminished the system availability and by inconsistent field ratings. Nevertheless, the current system reliability is consistent with degradation of less than 10% in 5 years and with estimates of less than 10% per year of the energy value for O and M.

  18. Reliability of photovoltaic systems - A field report

    Thomas, M. G.; Fuentes, M. K.; Lashway, C.; Black, B. D.

    Performance studies and field measurements of photovoltaic systems indicate a 1-2-percent/yr degradation in array energy production. The cause for much of the degradation has been identified as soiling, failed modules, and failures in interconnections. System performance evaluation continues to be complicated by the poor reliability of some power conditioning hardware (which greatly diminished system availability) and by inconsistent field ratings. Nevertheless, the current system reliability is consistent with degradation of less than 10 percent in 5 years and with estimates of less than 10 percent/yr of the energy value for O&M.

  19. Design for Reliability of Power Electronic Systems

    Wang, Huai; Ma, Ke; Blaabjerg, Frede


    availability, long lifetime, sufficient robustness, low maintenance cost and low cost of energy. However, the reliability predictions are still dominantly according to outdated models and terms, such as MIL-HDBK-217F handbook models, Mean-Time-To-Failure (MTTF), and Mean-Time-Between-Failures (MTBF......Advances in power electronics enable efficient and flexible processing of electric power in the application of renewable energy sources, electric vehicles, adjustable-speed drives, etc. More and more efforts are devoted to better power electronic systems in terms of reliability to ensure high......). A collection of methodologies based on Physics-of-Failure (PoF) approach and mission profile analysis are presented in this paper to perform reliability-oriented design of power electronic systems. The corresponding design procedures and reliability prediction models are provided. Further on, a case study...

  20. System Reliability for LED-Based Products

    Davis, J Lynn; Mills, Karmann; Lamvik, Michael; Yaga, Robert; Shepherd, Sarah D; Bittle, James; Baldasaro, Nick; Solano, Eric; Bobashev, Georgiy; Johnson, Cortina; Evans, Amy


    Results from accelerated life tests (ALT) on mass-produced commercially available 6” downlights are reported along with results from commercial LEDs. The luminaires capture many of the design features found in modern luminaires. In general, a systems perspective is required to understand the reliability of these devices since LED failure is rare. In contrast, components such as drivers, lenses, and reflector are more likely to impact luminaire reliability than LEDs.

  1. Software engineering practices for control system reliability

    S. K. Schaffner; K. S White


    This paper will discuss software engineering practices used to improve Control System reliability. The authors begin with a brief discussion of the Software Engineering Institute's Capability Maturity Model (CMM) which is a framework for evaluating and improving key practices used to enhance software development and maintenance capabilities. The software engineering processes developed and used by the Controls Group at the Thomas Jefferson National Accelerator Facility (Jefferson Lab), using the Experimental Physics and Industrial Control System (EPICS) for accelerator control, are described. Examples are given of how their procedures have been used to minimized control system downtime and improve reliability. While their examples are primarily drawn from their experience with EPICS, these practices are equally applicable to any control system. Specific issues addressed include resource allocation, developing reliable software lifecycle processes and risk management.

  2. Fast wafer-level detection and control of interconnect reliability

    Foley, Sean; Molyneaux, James; Mathewson, Alan


    Many of the technological advances in the semiconductor industry have led to dramatic increases in device density and performance in conjunction with enhanced circuit reliability. As reliability is improved, the time taken to characterize particular failure modes with traditional test methods is getting substantially longer. Furthermore, semiconductor customers expect low product cost and fast time-to-market. The limits of traditional reliability testing philosophies are being reached and new approaches need to be investigated to enable the next generation of highly reliable products to be tested. This is especially true in the area of IC interconnect, where significant challenges are predicted for the next decade. A number of fast, wafer level test methods exist for interconnect reliability evaluation. The relative abilities of four such methods to detect the quality and reliability of IC interconnect over very short test times are evaluated in this work. Four different test structure designs are also evaluated and the results are bench-marked against conventional package level Median Time to Failure results. The Isothermal test method combine with SWEAT-type test structures is shown to be the most suitable combination for defect detection and interconnect reliability control over very short test times.

  3. Reliability analysis of flood defence systems

    Steenbergen, H.M.G.M.; Lassing, B.L.; Vrouwenvelder, A.C.W.M.; Waarts, P.H.


    In recent years an advanced program for the reliability analysis of flood defence systems has been under development. This paper describes the global data requirements for the application and the setup of the models. The analysis generates the probability of system failure and the contribution of ea

  4. Bayesian system reliability assessment under fuzzy environments

    Wu, H.-C


    The Bayesian system reliability assessment under fuzzy environments is proposed in this paper. In order to apply the Bayesian approach, the fuzzy parameters are assumed as fuzzy random variables with fuzzy prior distributions. The (conventional) Bayes estimation method will be used to create the fuzzy Bayes point estimator of system reliability by invoking the well-known theorem called 'Resolution Identity' in fuzzy sets theory. On the other hand, we also provide the computational procedures to evaluate the membership degree of any given Bayes point estimate of system reliability. In order to achieve this purpose, we transform the original problem into a nonlinear programming problem. This nonlinear programming problem is then divided into four subproblems for the purpose of simplifying computation. Finally, the subproblems can be solved by using any commercial optimizers, e.g. GAMS or LINGO.

  5. Reliability-Based Optimization of Series Systems of Parallel Systems

    Enevoldsen, I.; Sørensen, John Dalsgaard

    Reliability-based design of structural systems is considered. Especially systems where the reliability model is a series system of parallel systems are analysed. A sensitivity analysis for this class of problems is presented. Direct and sequential optimization procedures to solve the optimization...... problems are described. Numerical tests indicate that a sequential technique called the bounds iteration method (BIM) is particularly fast and stable....

  6. Sustainable, Reliable Mission-Systems Architecture

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


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

  7. A new simulation estimator of system reliability

    Sheldon M. Ross


    Full Text Available A basic identity is proven and applied to obtain new simulation estimators concerning (a system reliability, (b a multi-valued system. We show that the variance of this new estimator is often of the order α2 when the usual raw estimator has variance of the order α and α is small. We also indicate how this estimator can be combined with standard variance reduction techniques of antithetic variables, stratified sampling and importance sampling.

  8. Reliable epileptic seizure detection using an improved wavelet neural network

    Zarita Zainuddin


    Full Text Available BackgroundElectroencephalogram (EEG signal analysis is indispensable in epilepsy diagnosis as it offers valuable insights for locating the abnormal distortions in the brain wave. However, visual interpretation of the massive amounts of EEG signals is time-consuming, and there is often inconsistent judgment between experts. AimsThis study proposes a novel and reliable seizure detection system, where the statistical features extracted from the discrete wavelet transform are used in conjunction with an improved wavelet neural network (WNN to identify the occurrence of seizures. Method Experimental simulations were carried out on a well-known publicly available dataset, which was kindly provided by the Epilepsy Center, University of Bonn, Germany. The normal and epileptic EEG signals were first pre-processed using the discrete wavelet transform. Subsequently, a set of statistical features was extracted to train a WNNs-based classifier. ResultsThe study has two key findings. First, simulation results showed that the proposed improved WNNs-based classifier gave excellent predictive ability, where an overall classification accuracy of 98.87% was obtained. Second, by using the 10th and 90th percentiles of the absolute values of the wavelet coefficients, a better set of EEG features can be identified from the data, as the outliers are removed before any further downstream analysis.ConclusionThe obtained high prediction accuracy demonstrated the feasibility of the proposed seizure detection scheme. It suggested the prospective implementation of the proposed method in developing a real time automated epileptic diagnostic system with fast and accurate response that could assist neurologists in the decision making process.

  9. 76 FR 42534 - Mandatory Reliability Standards for Interconnection Reliability Operating Limits; System...


    ... Reliability Operating Limits; System Restoration Reliability Standards AGENCY: Federal Energy Regulatory... necessary to analyze and monitor Interconnection Reliability Operating Limits (IROL) within its Wide-Area... Interconnection Reliability Operating Limits, Order No. 748, 134 FERC ] 61,213 (2011). \\2\\ The term...

  10. Mass and Reliability System (MaRS)

    Barnes, Sarah


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

  11. System Reliability Analysis of Redundant Condition Monitoring Systems

    YI Pengxing; HU Youming; YANG Shuzi; WU Bo; CUI Feng


    The development and application of new reliability models and methods are presented to analyze the system reliability of complex condition monitoring systems. The methods include a method analyzing failure modes of a type of redundant condition monitoring systems (RCMS) by invoking failure tree model, Markov modeling techniques for analyzing system reliability of RCMS, and methods for estimating Markov model parameters. Furthermore, a computing case is investigated and many conclusions upon this case are summarized. Results show that the method proposed here is practical and valuable for designing condition monitoring systems and their maintenance.

  12. Reliability of electrical power systems for coal mines

    Razgil' deev, G.I.; Kovalev, A.P.; Serkyuk, L.I.


    This is a method for evaluating the reliability of comprehensive mining power systems. The systems reliability is influenced by the selectivity of maximum protection, ground-short protection, the subdivision of the circuitry, the character of the systems failures, etc.

  13. Reliable neuronal systems: the importance of heterogeneity.

    Johannes Lengler

    Full Text Available For every engineer it goes without saying: in order to build a reliable system we need components that consistently behave precisely as they should. It is also well known that neurons, the building blocks of brains, do not satisfy this constraint. Even neurons of the same type come with huge variances in their properties and these properties also vary over time. Synapses, the connections between neurons, are highly unreliable in forwarding signals. In this paper we argue that both these fact add variance to neuronal processes, and that this variance is not a handicap of neural systems, but that instead predictable and reliable functional behavior of neural systems depends crucially on this variability. In particular, we show that higher variance allows a recurrently connected neural population to react more sensitively to incoming signals, and processes them faster and more energy efficient. This, for example, challenges the general assumption that the intrinsic variability of neurons in the brain is a defect that has to be overcome by synaptic plasticity in the process of learning.

  14. Computed tomography for the detection of distal radioulnar joint instability: normal variation and reliability of four CT scoring systems in 46 patients

    Wijffels, Mathieu; Krijnen, Pieta; Schipper, Inger [Leiden University Medical Center, Department of Surgery-Trauma Surgery, P.O. Box 9600, Leiden (Netherlands); Stomp, Wouter; Reijnierse, Monique [Leiden University Medical Center, Department of Radiology, P.O. Box 9600, Leiden (Netherlands)


    The diagnosis of distal radioulnar joint (DRUJ) instability is clinically challenging. Computed tomography (CT) may aid in the diagnosis, but the reliability and normal variation for DRUJ translation on CT have not been established in detail. The aim of this study was to evaluate inter- and intraobserver agreement and normal ranges of CT scoring methods for determination of DRUJ translation in both posttraumatic and uninjured wrists. Patients with a conservatively treated, unilateral distal radius fracture were included. CT scans of both wrists were evaluated independently, by two readers using the radioulnar line method, subluxation ratio method, epicenter method and radioulnar ratio method. The inter- and intraobserver agreement was assessed and normal values were determined based on the uninjured wrists. Ninety-two wrist CTs (mean age: 56.5 years, SD: 17.0, mean follow-up 4.2 years, SD: 0.5) were evaluated. Interobserver agreement was best for the epicenter method [ICC = 0.73, 95 % confidence interval (CI) 0.65-0.79]. Intraobserver agreement was almost perfect for the radioulnar line method (ICC = 0.82, 95 % CI 0.77-0.87). Each method showed a wide normal range for normal DRUJ translation. Normal range for the epicenter method is -0.35 to -0.06 in pronation and -0.11 to 0.19 in supination. DRUJ translation on CT in pro- and supination can be reliably evaluated in both normal and posttraumatic wrists, however with large normal variation. The epicenter method seems the most reliable. Scanning of both wrists might be helpful to prevent the radiological overdiagnosis of instability. (orig.)

  15. Parameter estimation and reliable fault detection of electric motors

    Dusan PROGOVAC; Le Yi WANG; George YIN


    Accurate model identification and fault detection are necessary for reliable motor control. Motor-characterizing parameters experience substantial changes due to aging, motor operating conditions, and faults. Consequently, motor parameters must be estimated accurately and reliably during operation. Based on enhanced model structures of electric motors that accommodate both normal and faulty modes, this paper introduces bias-corrected least-squares (LS) estimation algorithms that incorporate functions for correcting estimation bias, forgetting factors for capturing sudden faults, and recursive structures for efficient real-time implementation. Permanent magnet motors are used as a benchmark type for concrete algorithm development and evaluation. Algorithms are presented, their properties are established, and their accuracy and robustness are evaluated by simulation case studies under both normal operations and inter-turn winding faults. Implementation issues from different motor control schemes are also discussed.

  16. Software Reliability Cases: The Bridge Between Hardware, Software and System Safety and Reliability

    Herrmann, D.S.; Peercy, D.E.


    High integrity/high consequence systems must be safe and reliable; hence it is only logical that both software safety and software reliability cases should be developed. Risk assessments in safety cases evaluate the severity of the consequences of a hazard and the likelihood of it occurring. The likelihood is directly related to system and software reliability predictions. Software reliability cases, as promoted by SAE JA 1002 and 1003, provide a practical approach to bridge the gap between hardware reliability, software reliability, and system safety and reliability by using a common methodology and information structure. They also facilitate early insight into whether or not a project is on track for meeting stated safety and reliability goals, while facilitating an informed assessment by regulatory and/or contractual authorities.

  17. Reliability of immunohistochemical demonstration of oestrogen receptors in routine practice: interlaboratory variance in the sensitivity of detection and evaluation of scoring systems

    RHODES A.; Jasani, B; Barnes, D; Bobrow, L; Miller, K


    Aims—To investigate interlaboratory variance in the immunohistochemical (IHC) detection of oestrogen receptors so as to determine the rate of false negatives, which could adversely influence the decision to give adjuvant tamoxifen treatment.

  18. Dependent systems reliability estimation by structural reliability approach

    Kostandyan, Erik; Sørensen, John Dalsgaard


    ) and the component lifetimes follow some continuous and non-negative cumulative distribution functions. An illustrative example utilizing the proposed method is provided, where damage is modeled by a fracture mechanics approach with correlated components and a failure assessment diagram is applied for failure...... identification. Application of the proposed method can be found in many real world systems....

  19. Demand Response as a System Reliability Resource

    Eto, Joseph H. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Environmental Energy Technologies Division; Lewis, Nancy Jo [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Environmental Energy Technologies Division; Watson, David [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Environmental Energy Technologies Division; Kiliccote, Sila [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Environmental Energy Technologies Division; Auslander, David [Univ. of California, Berkeley, CA (United States); Paprotny, Igor [Univ. of California, Berkeley, CA (United States); Makarov, Yuri [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)


    The Demand Response as a System Reliability Resource project consists of six technical tasks: • Task 2.1. Test Plan and Conduct Tests: Contingency Reserves Demand Response (DR) Demonstration—a pioneering demonstration of how existing utility load-management assets can provide an important electricity system reliability resource known as contingency reserve. • Task 2.2. Participation in Electric Power Research Institute (EPRI) IntelliGrid—technical assistance to the EPRI IntelliGrid team in developing use cases and other high-level requirements for the architecture. • Task 2.3. Research, Development, and Demonstration (RD&D) Planning for Demand Response Technology Development—technical support to the Public Interest Energy Research (PIER) Program on five topics: Sub-task 1. PIER Smart Grid RD&D Planning Document; Sub-task 2. System Dynamics of Programmable Controllable Thermostats; Sub-task 3. California Independent System Operator (California ISO) DR Use Cases; Sub-task 4. California ISO Telemetry Requirements; and Sub-task 5. Design of a Building Load Data Storage Platform. • Task 2.4. Time Value of Demand Response—research that will enable California ISO to take better account of the speed of the resources that it deploys to ensure compliance with reliability rules for frequency control. • Task 2.5. System Integration and Market Research: Southern California Edison (SCE)—research and technical support for efforts led by SCE to conduct demand response pilot demonstrations to provide a contingency reserve service (known as non-spinning reserve) through a targeted sub-population of aggregated residential and small commercial customers enrolled in SCE’s traditional air conditioning (AC) load cycling program, the Summer Discount Plan. • Task 2.6. Demonstrate Demand Response Technologies: Pacific Gas and Electric (PG&E)—research and technical support for efforts led by PG&E to conduct a demand response pilot demonstration to provide non

  20. Integrated Reliability and Risk Analysis System (IRRAS)

    Russell, K D; McKay, M K; Sattison, M.B. Skinner, N.L.; Wood, S T [EG and G Idaho, Inc., Idaho Falls, ID (United States); Rasmuson, D M [Nuclear Regulatory Commission, Washington, DC (United States)


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

  1. Extrapolation Method for System Reliability Assessment

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


    The present paper presents a new scheme for probability integral solution for system reliability analysis, which takes basis in the approaches by Naess et al. (2009) and Bucher (2009). The idea is to evaluate the probability integral by extrapolation, based on a sequence of MC approximations....... The scheme is extended so that it can be applied to cases where the asymptotic property may not be valid and/or the random variables are not normally distributed. The performance of the scheme is investigated by four principal series and parallel systems and some practical examples. The results indicate...... of integrals with scaled domains. The performance of this class of approximation depends on the approach applied for the scaling and the functional form utilized for the extrapolation. A scheme for this task is derived here taking basis in the theory of asymptotic solutions to multinormal probability integrals...


    Yi Pengxing; Yang Shuzi; Du Runsheng; Wu Bo; Liu Shiyuan


    Taking into account the whole system structure and the component reliability estimation uncertainty, a system reliability estimation method based on probability and statistical theory for distributed monitoring systems is presented. The variance and confidence intervals of the system reliability estimation are obtained by expressing system reliability as a linear sum of products of higher order moments of component reliability estimates when the number of component or system survivals obeys binomial distribution. The eigenfunction of binomial distribution is used to determine the moments of component reliability estimates, and a symbolic matrix which can facilitate the search of explicit system reliability estimates is proposed. Furthermore, a case of application is used to illustrate the procedure, and with the help of this example, various issues such as the applicability of this estimation model, and measures to improve system reliability of monitoring systems are discussed.


    Adrian Stere PARIS


    Full Text Available Manufacturing systems are characterized by three fundamental properties: performance, cost, and dependability. The analysis of a system from the pure performance viewpoint tends to be optimistic since it ignores the failure/repair behaviour in the system. On the other hand, pure availability analysis tends to be too conservative since performance considerations are not taken into account. They improve product quality and reduce production losses. Dependability of a manufacturing system is the ability to deliver service (products that can justifiably be trusted. Performance engineering addresses sustainability along with other factors like quality, reliability, maintainability and safety. The current paper introduces a framework for the fault analysis of production process, and the availability evaluation especially in the Flexible Manufacturing Systems (FMS’s. Generally, computing dependability measures of repairable systems with usual failure and repair processes is difficult, through either analytical or numerical methods. Mathematical models and application software for this kind of problems are in good stead. Recent advances in neural networks show that they can be used in applications that involve predictions, including the manufacturing.

  4. A computational method for reliable gait event detection and abnormality detection for feedback in rehabilitation.

    Senanayake, Chathuri; Senanayake, S M N Arosha


    In this paper, a gait event detection algorithm is presented that uses computer intelligence (fuzzy logic) to identify seven gait phases in walking gait. Two inertial measurement units and four force-sensitive resistors were used to obtain knee angle and foot pressure patterns, respectively. Fuzzy logic is used to address the complexity in distinguishing gait phases based on discrete events. A novel application of the seven-dimensional vector analysis method to estimate the amount of abnormalities detected was also investigated based on the two gait parameters. Experiments were carried out to validate the application of the two proposed algorithms to provide accurate feedback in rehabilitation. The algorithm responses were tested for two cases, normal and abnormal gait. The large amount of data required for reliable gait-phase detection necessitate the utilisation of computer methods to store and manage the data. Therefore, a database management system and an interactive graphical user interface were developed for the utilisation of the overall system in a clinical environment.

  5. Diagnostics and reliability of pipeline systems

    Timashev, Sviatoslav


    The book contains solutions to fundamental problems which arise due to the logic of development of specific branches of science, which are related to pipeline safety, but mainly are subordinate to the needs of pipeline transportation.          The book deploys important but not yet solved aspects of reliability and safety assurance of pipeline systems, which are vital aspects not only for the oil and gas industry and, in general, fuel and energy industries , but also to virtually all contemporary industries and technologies. The volume will be useful to specialists and experts in the field of diagnostics/ inspection, monitoring, reliability and safety of critical infrastructures. First and foremost, it will be useful to the decision making persons —operators of different types of pipelines, pipeline diagnostics/inspection vendors, and designers of in-line –inspection (ILI) tools, industrial and ecological safety specialists, as well as to researchers and graduate students.

  6. Reliability analysis and updating of deteriorating systems with subset simulation

    Schneider, Ronald; Thöns, Sebastian; Straub, Daniel


    Bayesian updating of the system deterioration model. The updated system reliability is then obtained through coupling the updated deterioration model with a probabilistic structural model. The underlying high-dimensional structural reliability problems are solved using subset simulation, which...

  7. A Method of Reliability Allocation of a Complicated Large System

    WANG Zhi-sheng; QIN Yuan-yuan; WANG Dao-bo


    Aiming at the problem of reliability allocation for a complicated large system, a new thought is brought up. Reliability allocation should be a kind of decision-making behavior; therefore the more information is used when apportioning a reliability index, the more reasonable an allocation is obtained. Reliability allocation for a complicated large system consists of two processes, the first one is a reliability information reporting process fromt bottom to top, and the other one is a reliability index apportioning process from top to bottom. By a typical example, we illustrate the concrete process of reliability allocation algorithms.

  8. 77 FR 7526 - Interpretation of Protection System Reliability Standard


    ... Protection System maintenance and testing standard that were identified by the NOPR within the Reliability... Reliability Standards development process to address gaps in the Protection System maintenance and testing... Protection System maintenance and testing standard that were identified by the NOPR within the Reliability...

  9. 75 FR 81152 - Interpretation of Protection System Reliability Standard


    ... Systems that affect the reliability of the BES. The program shall include: R1.1. Maintenance and testing... provide a complete framework for maintenance and testing of equipment necessary to ensure the reliability... maintenance and testing of Protection Systems affecting the reliability of the Bulk-Power System. 13. If...

  10. Modular System Modeling for Quantitative Reliability Evaluation of Technical Systems

    Stephan Neumann


    Full Text Available In modern times, it is necessary to offer reliable products to match the statutory directives concerning product liability and the high expectations of customers for durable devices. Furthermore, to maintain a high competitiveness, engineers need to know as accurately as possible how long their product will last and how to influence the life expectancy without expensive and time-consuming testing. As the components of a system are responsible for the system reliability, this paper introduces and evaluates calculation methods for life expectancy of common machine elements in technical systems. Subsequently, a method for the quantitative evaluation of the reliability of technical systems is proposed and applied to a heavy-duty power shift transmission.

  11. Development of Reliable Life Support Systems

    Carter, Layne


    The life support systems on the International Space Station (ISS) are the culmination of an extensive effort encompassing development, design, and test to provide the highest possible confidence in their operation on ISS. Many years of development testing are initially performed to identify the optimum technology and the optimum operational approach. The success of this development program depends on the accuracy of the system interfaces. The critical interfaces include the specific operational environment, the composition of the waste stream to be processed and the quality of the product. Once the development program is complete, a detailed system schematic is built based on the specific design requirements, followed by component procurement, assembly, and acceptance testing. A successful acceptance test again depends on accurately simulating the anticipated environment on ISS. The ISS Water Recovery System (WRS) provides an excellent example of where this process worked, as well as lessons learned that can be applied to the success of future missions. More importantly, ISS has provided a test bed to identify these design issues. Mechanical design issues have included an unreliable harmonic drive train in the Urine Processor's fluids pump, and seals in the Water Processor's Catalytic Reactor with insufficient life at the operational temperature. Systems issues have included elevated calcium in crew urine (due to microgravity effect) that resulted in precipitation at the desired water recovery rate, and the presence of an organosilicon compound (dimethylsilanediol) in the condensate that is not well removed by the water treatment process. Modifications to the WRS to address these issues are either complete (and now being evaluated on ISS) or are currently in work to insure the WRS has the required reliability before embarking on a mission to Mars.

  12. A Reliable Identification System for Red Palm Weevil

    Saleh Mufleh Al-Saqer


    Full Text Available Problem statement: Red Palm Weevil (RPW is a widely found pest among palm trees and is known to cause significant losses every year to palm growers. Existing identification techniques for RPW comprise of using traps with pheromones to detect these pests. However, these traditional methods are labor-intensive, expensive to implement and unreliable for early detection of RPW infestation. Early detection of these pests would provide the best opportunity to eradicate them and minimize the potential losses of palm trees. Approach: In this study, a reliable identification system is developed to identify RPW by using only a small number of image descriptors in combination with neural network models. The neural networks were developed by using between three to nine image descriptors as inputs and a large database of insects’ images was used for training. Three different training ratios ranging from 25-75% were used and the network was trained by two different algorithms. Further, several scenarios were formulated to test the efficacy and reliability of the newly developed identification system. Results: The results indicate that the identification system developed in this study is capable of 100% recognition of RPW and 93% recognition of other insects in the database by taking as input only three easily-calculable image descriptors. Further, the average training times for these networks was 13 sec and the testing time for a single image was only 0.015 sec. Conclusion: The new system developed in this study provided reliable identification for RPW and was found to be up to 14 times faster in training and three times faster in testing of insects’ images.

  13. Composite system reliability evaluation by stochastic calculation of system operation

    Haubrick, H.-J.; Hinz, H.-J.; Landeck, E. [Dept. of Power Systems and Power Economics (Germany)


    This report describes a new developed probabilistic approach for steady-state composite system reliability evaluation and its exemplary application to a bulk power test system. The new computer program called PHOENIX takes into consideration transmission limitations, outages of lines and power stations and, as a central element, a highly sophisticated model to the dispatcher performing remedial actions after disturbances. The kernel of the new method is a procedure for optimal power flow calculation that has been specially adapted for the use in reliability evaluations under the above mentioned conditions. (author) 11 refs., 8 figs., 1 tab.

  14. Response and Reliability Problems of Dynamic Systems

    Nielsen, Søren R. K.

    The present thesis consists of selected parts of the work performed by the author on stochastic dynamics and reliability theory of dynamically excited structures primarily during the period 1986-1996.......The present thesis consists of selected parts of the work performed by the author on stochastic dynamics and reliability theory of dynamically excited structures primarily during the period 1986-1996....

  15. Reliability program requirements for aeronautical and space system contractors


    General reliability program requirements for NASA contracts involving the design, development, fabrication, test, and/or use of aeronautical and space systems including critical ground support equipment are prescribed. The reliability program requirements require (1) thorough planning and effective management of the reliability effort; (2) definition of the major reliability tasks and their place as an integral part of the design and development process; (3) planning and evaluating the reliability of the system and its elements (including effects of software interfaces) through a program of analysis, review, and test; and (4) timely status indication by formal documentation and other reporting to facilitate control of the reliability program.

  16. High Reliability Oscillators for Terahertz Systems Project

    National Aeronautics and Space Administration — To develop reliable THz sources with high power and high DC-RF efficiency, Virginia Diodes, Inc. will develop a thorough understanding of the complex interactions...

  17. System reliability analysis for kinematic performance of planar mechanisms

    ZHANG YiMin; HUANG XianZhen; ZHANG XuFang; HE XiangDong; WEN BangChun


    Based on the reliability and mechanism kinematic accuracy theories, we propose a general methodology for system reliability analysis of kinematic performance of planar mechanisms. The loop closure equations are used to estimate the kinematic performance errors of planar mechanisms. Reliability and system reliability theories are introduced to develop the limit state functions (LSF) for failure of kinematic performance qualities. The statistical fourth moment method and the Edgeworth series technique are used on system reliability analysis for kinematic performance of planar mechanisms, which relax the restrictions of probability distribution of design variables. Finally, the practicality, efficiency and accuracy of the proposed method are demonstrated by numerical examples.

  18. Reliability Estimations of Control Systems Effected by Several Interference Sources

    DengBei-xing; JiangMing-hu; LiXing


    In order to establish the sufficient and necessary condition that arbitrarily reliable systems can not be constructed with function elements under interference sources, it is very important to expand set of interference sources with the above property. In this paper, the models of two types of interference sources are raised respectively: interference source possessing real input vectors and constant reliable interferen cesource. We study the reliability of the systems effected by the interference sources, and the lower bound of the reliability is presented. The results show that it is impossible that arbitrarily reliable systems can not be constructed with the elements effected by above interference sources.

  19. System principles, mathematical models and methods to ensure high reliability of safety systems

    Zaslavskyi, V.


    Modern safety and security systems are composed of a large number of various components designed for detection, localization, tracking, collecting, and processing of information from the systems of monitoring, telemetry, control, etc. They are required to be highly reliable in a view to correctly perform data aggregation, processing and analysis for subsequent decision making support. On design and construction phases of the manufacturing of such systems a various types of components (elements, devices, and subsystems) are considered and used to ensure high reliability of signals detection, noise isolation, and erroneous commands reduction. When generating design solutions for highly reliable systems a number of restrictions and conditions such as types of components and various constrains on resources should be considered. Various types of components perform identical functions; however, they are implemented using diverse principles, approaches and have distinct technical and economic indicators such as cost or power consumption. The systematic use of different component types increases the probability of tasks performing and eliminates the common cause failure. We consider type-variety principle as an engineering principle of system analysis, mathematical models based on this principle, and algorithms for solving optimization problems of highly reliable safety and security systems design. Mathematical models are formalized in a class of two-level discrete optimization problems of large dimension. The proposed approach, mathematical models, algorithms can be used for problem solving of optimal redundancy on the basis of a variety of methods and control devices for fault and defects detection in technical systems, telecommunication networks, and energy systems.

  20. Interior intrusion detection systems

    Rodriguez, J.R.; Matter, J.C. (Sandia National Labs., Albuquerque, NM (United States)); Dry, B. (BE, Inc., Barnwell, SC (United States))


    The purpose of this NUREG is to present technical information that should be useful to NRC licensees in designing interior intrusion detection systems. Interior intrusion sensors are discussed according to their primary application: boundary-penetration detection, volumetric detection, and point protection. Information necessary for implementation of an effective interior intrusion detection system is presented, including principles of operation, performance characteristics and guidelines for design, procurement, installation, testing, and maintenance. A glossary of sensor data terms is included. 36 figs., 6 tabs.

  1. Interior intrusion detection systems

    Rodriguez, J.R.; Matter, J.C. (Sandia National Labs., Albuquerque, NM (United States)); Dry, B. (BE, Inc., Barnwell, SC (United States))


    The purpose of this NUREG is to present technical information that should be useful to NRC licensees in designing interior intrusion detection systems. Interior intrusion sensors are discussed according to their primary application: boundary-penetration detection, volumetric detection, and point protection. Information necessary for implementation of an effective interior intrusion detection system is presented, including principles of operation, performance characteristics and guidelines for design, procurement, installation, testing, and maintenance. A glossary of sensor data terms is included. 36 figs., 6 tabs.

  2. LMI approach to reliable H∞ control of linear systems

    Yao Bo; Wang Fuzhong


    The reliable design problem for linear systems is concerned with. A more practical model of actuator faults than outage is considered. An LMI approach of designing reliable controller is presented for the case of actuator faults that can be modeled by a scaling factor. The resulting control systems are reliable in that they provide guaranteed asymptotic stability and H∞ performance when some control component (actuator) faults occur. A numerical example is also given to illustrate the design procedure and their effectiveness. Furthermore, the optimal standard controller and the optimal reliable controller are compared to show the necessity of reliable control.

  3. The 747 primary flight control systems reliability and maintenance study


    The major operational characteristics of the 747 Primary Flight Control Systems (PFCS) are described. Results of reliability analysis for separate control functions are presented. The analysis makes use of a NASA computer program which calculates reliability of redundant systems. Costs for maintaining the 747 PFCS in airline service are assessed. The reliabilities and cost will provide a baseline for use in trade studies of future flight control system design.

  4. Fatigue Reliability of Offshore Wind Turbine Systems

    Marquez-Dominguez, Sergio; Sørensen, John Dalsgaard


    Optimization of the design of offshore wind turbine substructures with respect to fatigue loads is an important issue in offshore wind energy. A stochastic model is developed for assessing the fatigue failure reliability. This model can be used for direct probabilistic design and for calibration...... of appropriate partial safety factors / fatigue design factors (FDF) for steel substructures of offshore wind turbines (OWTs). The fatigue life is modeled by the SN approach. Design and limit state equations are established based on the accumulated fatigue damage. The acceptable reliability level for optimal...

  5. Optimization of life support systems and their systems reliability

    Fan, L. T.; Hwang, C. L.; Erickson, L. E.


    The identification, analysis, and optimization of life support systems and subsystems have been investigated. For each system or subsystem that has been considered, the procedure involves the establishment of a set of system equations (or mathematical model) based on theory and experimental evidences; the analysis and simulation of the model; the optimization of the operation, control, and reliability; analysis of sensitivity of the system based on the model; and, if possible, experimental verification of the theoretical and computational results. Research activities include: (1) modeling of air flow in a confined space; (2) review of several different gas-liquid contactors utilizing centrifugal force: (3) review of carbon dioxide reduction contactors in space vehicles and other enclosed structures: (4) application of modern optimal control theory to environmental control of confined spaces; (5) optimal control of class of nonlinear diffusional distributed parameter systems: (6) optimization of system reliability of life support systems and sub-systems: (7) modeling, simulation and optimal control of the human thermal system: and (8) analysis and optimization of the water-vapor eletrolysis cell.

  6. Objective Methods for Reliable Detection of Concealed Depression

    Cynthia eSolomon


    Full Text Available Recent research has shown that it is possible to automatically detect clinical depression from audio-visual recordings. Before considering integration in a clinical pathway, a key question that must be asked is whether such systems can be easily fooled. This work explores the potential of acoustic features to detect clinical depression in adults both when acting normally and when asked to conceal their depression. Nine adults diagnosed with mild to moderate depression as per the Beck Depression Inventory (BDI-II and Patient Health Questionnaire (PHQ-9 were asked a series of questions and to read a excerpt from a novel aloud under two different experimental conditions. In one, participants were asked to act naturally and in the other, to suppress anything that they felt would be indicative of their depression. Acoustic features were then extracted from this data and analysed using paired t-tests to determine any statistically significant differences between healthy and depressed participants. Most features that were found to be significantly different during normal behaviour remained so during concealed behaviour. In leave-one-subject-out automatic classification studies of the 9 depressed subjects and 8 matched healthy controls, an 88% classification accuracy and 89% sensitivity was achieved. Results remained relatively robust during concealed behaviour, with classifiers trained on only non-concealed data achieving 81% detection accuracy and 75% sensitivity when tested on concealed data. These results indicate there is good potential to build deception-proof automatic depression monitoring systems.

  7. Reliability of digital reactor protection system based on extenics.

    Zhao, Jing; He, Ya-Nan; Gu, Peng-Fei; Chen, Wei-Hua; Gao, Feng


    After the Fukushima nuclear accident, safety of nuclear power plants (NPPs) is widespread concerned. The reliability of reactor protection system (RPS) is directly related to the safety of NPPs, however, it is difficult to accurately evaluate the reliability of digital RPS. The method is based on estimating probability has some uncertainties, which can not reflect the reliability status of RPS dynamically and support the maintenance and troubleshooting. In this paper, the reliability quantitative analysis method based on extenics is proposed for the digital RPS (safety-critical), by which the relationship between the reliability and response time of RPS is constructed. The reliability of the RPS for CPR1000 NPP is modeled and analyzed by the proposed method as an example. The results show that the proposed method is capable to estimate the RPS reliability effectively and provide support to maintenance and troubleshooting of digital RPS system.

  8. Integrated Software Architecture-Based Reliability Prediction for IT Systems

    Brosch, Franz


    With the increasing importance of reliability in business and industrial IT systems, new techniques for architecture-based software reliability prediction are becoming an integral part of the development process. This dissertation thesis introduces a novel reliability modelling and prediction technique that considers the software architecture with its component structure, control and data flow, recovery mechanisms, its deployment to distributed hardware resources and the system´s usage p...

  9. Computer System Reliability Allocation Method and Supporting Tool


    This paper presents a computer system reliability allocationmethod that is based on the theory of statistic and Markovian chain,which can be used to allocate reliability to subsystem, to hybrid system and software modules. Arele vant supporting tool built by us is introduced.

  10. Reliability and safety analysis of redundant vehicle management computer system

    Shi Jian; Meng Yixuan; Wang Shaoping; Bian Mengmeng; Yan Dungong


    Redundant techniques are widely adopted in vehicle management computer (VMC) to ensure that VMC has high reliability and safety. At the same time, it makes VMC have special char-acteristics, e.g., failure correlation, event simultaneity, and failure self-recovery. Accordingly, the reliability and safety analysis to redundant VMC system (RVMCS) becomes more difficult. Aimed at the difficulties in RVMCS reliability modeling, this paper adopts generalized stochastic Petri nets to establish the reliability and safety models of RVMCS. Then this paper analyzes RVMCS oper-ating states and potential threats to flight control system. It is verified by simulation that the reli-ability of VMC is not the product of hardware reliability and software reliability, and the interactions between hardware and software faults can reduce the real reliability of VMC obviously. Furthermore, the failure undetected states and false alarming states inevitably exist in RVMCS due to the influences of limited fault monitoring coverage and false alarming probability of fault mon-itoring devices (FMD). RVMCS operating in some failure undetected states will produce fatal threats to the safety of flight control system. RVMCS operating in some false alarming states will reduce utility of RVMCS obviously. The results abstracted in this paper can guide reliable VMC and efficient FMD designs. The methods adopted in this paper can also be used to analyze other intelligent systems’ reliability.

  11. Distribution System Reliability Evaluation Taking Circuit Capacity into Consideration


    Distribution system reliability evaluation using the method ofconnectivity ignores the effect of operation constraints. This paper presents an approach that includes the effect of circuit capacity. Reliability evaluation of distribution systems with parallel circuits generally requires load flow solutions. The proposed approach combines the Z-matrix contingency method with DC load flow for a much faster direct solution. Three different methods for distribution system reliability evaluation have been incorporated into a computer program. The program was validated using two distribution systems connected to the IEEE-RTS and another sample distribution system.

  12. Reliability models applicable to space telescope solar array assembly system

    Patil, S. A.


    A complex system may consist of a number of subsystems with several components in series, parallel, or combination of both series and parallel. In order to predict how well the system will perform, it is necessary to know the reliabilities of the subsystems and the reliability of the whole system. The objective of the present study is to develop mathematical models of the reliability which are applicable to complex systems. The models are determined by assuming k failures out of n components in a subsystem. By taking k = 1 and k = n, these models reduce to parallel and series models; hence, the models can be specialized to parallel, series combination systems. The models are developed by assuming the failure rates of the components as functions of time and as such, can be applied to processes with or without aging effects. The reliability models are further specialized to Space Telescope Solar Arrray (STSA) System. The STSA consists of 20 identical solar panel assemblies (SPA's). The reliabilities of the SPA's are determined by the reliabilities of solar cell strings, interconnects, and diodes. The estimates of the reliability of the system for one to five years are calculated by using the reliability estimates of solar cells and interconnects given n ESA documents. Aging effects in relation to breaks in interconnects are discussed.

  13. Reliability impact of solar electric generation upon electric utility systems

    Day, J. T.; Hobbs, W. J.


    The introduction of solar electric systems into an electric utility grid brings new considerations in the assessment of the utility's power supply reliability. This paper summarizes a methodology for estimating the reliability impact of solar electric technologies upon electric utilities for value assessment and planning purposes. Utility expansion and operating impacts are considered. Sample results from photovoltaic analysis show that solar electric plants can increase the reliable load-carrying capability of a utility system. However, the load-carrying capability of the incremental power tends to decrease, particularly at significant capacity penetration levels. Other factors influencing reliability impact are identified.

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

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


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

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

    Gupta, G.K.; Sedding, H.G.; Culbert, I.M. [Ontario Hydro, Toronto, ON, (Canada)


    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)

  16. Reliability Architecture for Collaborative Robot Control Systems in Complex Environments

    Liang Tang


    Full Text Available Many different kinds of robot systems have been successfully deployed in complex environments, while research into collaborative control systems between different robots, which can be seen as a hybrid internetware safety-critical system, has become essential. This paper discusses ways to construct robust and secure reliability architecture for collaborative robot control systems in complex environments. First, the indication system for evaluating the realtime reliability of hybrid internetware systems is established. Next, a dynamic collaborative reliability model for components of hybrid internetware systems is proposed. Then, a reliable, adaptive and evolutionary computation method for hybrid internetware systems is proposed, and a timing consistency verification solution for collaborative robot control internetware applications is studied. Finally, a multi-level security model supporting dynamic resource allocation is established.

  17. Semiconductor radiation detection systems


    Covers research in semiconductor detector and integrated circuit design in the context of medical imaging using ionizing radiation. This book explores other applications of semiconductor radiation detection systems in security applications such as luggage scanning, dirty bomb detection and border control.

  18. PV system field experience and reliability

    Durand, Steven; Rosenthal, Andrew; Thomas, Mike


    Hybrid power systems consisting of battery inverters coupled with diesel, propane, or gasoline engine-driven electrical generators, and photovoltaic arrays are being used in many remote locations. The potential cost advantages of hybrid systems over simple engine-driven generator systems are causing hybrid systems to be considered for numerous applications including single-family residential, communications, and village power. This paper discusses the various design constraints of such systems and presents one technique for reducing hybrid system losses. The Southwest Technology Development Institute under contract to the National Renewable Energy Laboratory and Sandia National Laboratories has been installing data acquisition systems (DAS) on a number of small and large hybrid PV systems. These systems range from small residential systems (1 kW PV - 7 kW generator), to medium sized systems (10 kW PV - 20 kW generator), to larger systems (100 kW PV - 200 kW generator). Even larger systems are being installed with hundreds of kilowatts of PV modules, multiple wind machines, and larger diesel generators.

  19. Towards Reliable Evaluation of Anomaly-Based Intrusion Detection Performance

    Viswanathan, Arun


    This report describes the results of research into the effects of environment-induced noise on the evaluation process for anomaly detectors in the cyber security domain. This research was conducted during a 10-week summer internship program from the 19th of August, 2012 to the 23rd of August, 2012 at the Jet Propulsion Laboratory in Pasadena, California. The research performed lies within the larger context of the Los Angeles Department of Water and Power (LADWP) Smart Grid cyber security project, a Department of Energy (DoE) funded effort involving the Jet Propulsion Laboratory, California Institute of Technology and the University of Southern California/ Information Sciences Institute. The results of the present effort constitute an important contribution towards building more rigorous evaluation paradigms for anomaly-based intrusion detectors in complex cyber physical systems such as the Smart Grid. Anomaly detection is a key strategy for cyber intrusion detection and operates by identifying deviations from profiles of nominal behavior and are thus conceptually appealing for detecting "novel" attacks. Evaluating the performance of such a detector requires assessing: (a) how well it captures the model of nominal behavior, and (b) how well it detects attacks (deviations from normality). Current evaluation methods produce results that give insufficient insight into the operation of a detector, inevitably resulting in a significantly poor characterization of a detectors performance. In this work, we first describe a preliminary taxonomy of key evaluation constructs that are necessary for establishing rigor in the evaluation regime of an anomaly detector. We then focus on clarifying the impact of the operational environment on the manifestation of attacks in monitored data. We show how dynamic and evolving environments can introduce high variability into the data stream perturbing detector performance. Prior research has focused on understanding the impact of this

  20. Reliability analysis and initial requirements for FC systems and stacks

    Åström, K.; Fontell, E.; Virtanen, S.

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

  1. Assessment on reliability of water quality in water distribution systems

    伍悦滨; 田海; 王龙岩


    Water leaving the treatment works is usually of a high quality but its properties change during the transportation stage. Increasing awareness of the quality of the service provided within the water industry today and assessing the reliability of the water quality in a distribution system has become a major significance for decision on system operation based on water quality in distribution networks. Using together a water age model, a chlorine decay model and a model of acceptable maximum water age can assess the reliability of the water quality in a distribution system. First, the nodal water age values in a certain complex distribution system can be calculated by the water age model. Then, the acceptable maximum water age value in the distribution system is obtained based on the chlorine decay model. The nodes at which the water age values are below the maximum value are regarded as reliable nodes. Finally, the reliability index on the percentile weighted by the nodal demands reflects the reliability of the water quality in the distribution system. The approach has been applied in a real water distribution network. The contour plot based on the water age values determines a surface of the reliability of the water quality. At any time, this surface is used to locate high water age but poor reliability areas, which identify parts of the network that may be of poor water quality. As a result, the contour water age provides a valuable aid for a straight insight into the water quality in the distribution system.

  2. Ultra-Reliable Communication in 5G Wireless Systems

    Popovski, Petar


    —Wireless 5G systems will not only be “4G, but faster”. One of the novel features discussed in relation to 5G is Ultra-Reliable Communication (URC), an operation mode not present in today’s wireless systems. URC refers to provision of certain level of communication service almost 100 % of the time....... Example URC applications include reliable cloud connectivity, critical connections for industrial automation and reliable wireless coordination among vehicles. This paper puts forward a systematic view on URC in 5G wireless systems. It starts by analyzing the fundamental mechanisms that constitute......-term URC (URC-S). The second dimension is represented by the type of reliability impairment that can affect the communication reliability in a given scenario. The main objective of this paper is to create the context for defining and solving the new engineering problems posed by URC in 5G....

  3. Reliability Estimations of Control Systems Effected by Several Interference Sources

    Deng Bei-xing; Jiang Ming-hu; Li Xing


    In order to estab lish the sufficient and necessary condition that arbitrarily reliable systems can not be construc-ted with function elements under interference sources, it is very important to expand set of interference sources with the above property. In this paper, the models of two types of in-terference sources are raised respectively: interference source possessing real input vectors and constant reliable interference source. We study the reliability of the systems effected by the interference sources, and the lower bound of the reliability is presented. The results show that it is impossible that arbi-trarily reliable systems can not be constructed with the ele-ments effected by above interference sources.

  4. Seismic reliability analysis of large electric power systems

    何军; 李杰


    Based on the De. Morgan laws and Boolean simplification, a recursive decomposition method is introduced in this paper to identity the main exclusive safe paths and failed paths of a network. The reliability or the reliability bound of a network can be conveniently expressed as the summation of the joint probabilities of these paths. Under the multivariate normal distribution assumption, a conditioned reliability index method is developed to evaluate joint probabilities of various exclusive safe paths and failed paths, and, finally, the seismic reliability or the reliability bound of an electric power system.Examples given in thc paper show that the method is very simple and provides accurate results in the seismic reliability analysis.

  5. Reliability Growth Analysis of Satellite Systems


    obtained. In addition, the Cumulative Intensity Function ( CIF ) of a family of satellite systems was analyzed to assess its similarity to that of a...parameters are obtained. In addition, the Cumulative Intensity Function ( CIF ) of a family of satellite systems was analyzed to assess its similarity to that...System Figures 7a through 7i display the real CIF for a variety of GOES missions. These cumulative intensity functions have shapes similar to the

  6. Reliable High Performance Processing System (RHPPS) Project

    National Aeronautics and Space Administration — NASA's exploration, science, and space operations systems are critically dependent on the hardware technologies used in their implementation. Specifically, the...

  7. Reliability of Structural Systems with Correlated Elements

    Thoft-Christensen, Palle; Sørensen, John Dalsgaard


    Calculation of the probability of failure of a system with correlation members is usually a difficult and time-consuming numerical problem. However, for some types of systems with equally correlated elements this calculation can be performed in a simple way. This has suggested two new methods based...

  8. Engineering systems reliability, safety, and maintenance an integrated approach

    Dhillon, B S


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




    Full Text Available The introduction of pervasive devices and mobile devices has led to immense growth of real time distributed processing. In such context reliability of the computing environment is very important. Reliability is the probability that the devices, links, processes, programs and files work efficiently for the specified period of time and in the specified condition. Distributed systems are available as conventional ring networks, clusters and agent based systems. Reliability of such systems is focused. These networks are heterogeneous and scalable in nature. There are several factors, which are to be considered for reliability estimation. These include the application related factors like algorithms, data-set sizes, memory usage pattern, input-output, communication patterns, task granularity and load-balancing. It also includes the hardware related factors like processor architecture, memory hierarchy, input-output configuration and network. The software related factors concerning reliability are operating systems, compiler, communication protocols, libraries and preprocessor performance. In estimating the reliability of a system, the performance estimation is an important aspect. Reliability analysis is approached using probability.

  10. Reliability analysis of ship structure system with multi-defects


    This paper analyzes the influence of multi-defects including the initial distortions,welding residual stresses,cracks and local dents on the ultimate strength of the plate element,and has worked out expressions of reliability calculation and sensitivity analysis of the plate element.Reliability analysis is made for the system with multi-defects plate elements.Failure mechanism,failure paths and the calculating approach to global reliability index are also worked out.After plate elements with multi-defects fail,the formula of reverse node forces which affect the residual structure is deduced,so are the sensitivity expressions of the system reliability index.This ensures calculating accuracy and rationality for reliability analysis,and makes it convenient to find weakness plate elements which affect the reliability of the structure system.Finally,for the validity of the approach proposed,we take the numerical example of a ship cabin to compare and contrast the reliability and the sensitivity analysis of the structure system with multi-defects with those of the structure system with no defects.The approach has implications for the structure design,rational maintenance and renewing strategy.

  11. A Passive System Reliability Analysis for a Station Blackout

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


    The latest iterations of advanced reactor designs have included increased reliance on passive safety systems to maintain plant integrity during unplanned sequences. While these systems are advantageous in reducing the reliance on human intervention and availability of power, the phenomenological foundations on which these systems are built require a novel approach to a reliability assessment. Passive systems possess the unique ability to fail functionally without failing physically, a result of their explicit dependency on existing boundary conditions that drive their operating mode and capacity. Argonne National Laboratory is performing ongoing analyses that demonstrate various methodologies for the characterization of passive system reliability within a probabilistic framework. Two reliability analysis techniques are utilized in this work. The first approach, the Reliability Method for Passive Systems, provides a mechanistic technique employing deterministic models and conventional static event trees. The second approach, a simulation-based technique, utilizes discrete dynamic event trees to treat time- dependent phenomena during scenario evolution. For this demonstration analysis, both reliability assessment techniques are used to analyze an extended station blackout in a pool-type sodium fast reactor (SFR) coupled with a reactor cavity cooling system (RCCS). This work demonstrates the entire process of a passive system reliability analysis, including identification of important parameters and failure metrics, treatment of uncertainties and analysis of results.

  12. Diverse Redundant Systems for Reliable Space Life Support

    Jones, Harry W.


    Reliable life support systems are required for deep space missions. The probability of a fatal life support failure should be less than one in a thousand in a multi-year mission. It is far too expensive to develop a single system with such high reliability. Using three redundant units would require only that each have a failure probability of one in ten over the mission. Since the system development cost is inverse to the failure probability, this would cut cost by a factor of one hundred. Using replaceable subsystems instead of full systems would further cut cost. Using full sets of replaceable components improves reliability more than using complete systems as spares, since a set of components could repair many different failures instead of just one. Replaceable components would require more tools, space, and planning than full systems or replaceable subsystems. However, identical system redundancy cannot be relied on in practice. Common cause failures can disable all the identical redundant systems. Typical levels of common cause failures will defeat redundancy greater than two. Diverse redundant systems are required for reliable space life support. Three, four, or five diverse redundant systems could be needed for sufficient reliability. One system with lower level repair could be substituted for two diverse systems to save cost.

  13. System reliability effects in wind turbine blades

    Dimitrov, Nikolay Krasimirov; Friis-Hansen, Peter; Berggreen, Christian


    Laminated composite sandwich panels have a layered structure, where individual layers have randomly varying stiffness and strength properties. The presence of multiple failure modes and load redistribution following partial failures are the reason for laminated composites to exhibit system behavior...

  14. Is sequential cranial ultrasound reliable for detection of white matter injury in very preterm infants?

    Leijser, Lara M.; Steggerda, Sylke J.; Walther, Frans J.; Wezel-Meijler, Gerda van [Leiden University Medical Center, Department of Pediatrics, Division of Neonatology, Leiden (Netherlands); Bruine, Francisca T. de; Grond, Jeroen van der [Leiden University Medical Center, Department of Radiology, Division of Neuroradiology, Leiden (Netherlands)


    Cranial ultrasound (cUS) may not be reliable for detection of diffuse white matter (WM) injury. Our aim was to assess in very preterm infants the reliability of a classification system for WM injury on sequential cUS throughout the neonatal period, using magnetic resonance imaging (MRI) as reference standard. In 110 very preterm infants (gestational age <32 weeks), serial cUS during admission (median 8, range 4-22) and again around term equivalent age (TEA) and a single MRI around TEA were performed. cUS during admission were assessed for presence of WM changes, and contemporaneous cUS and MRI around TEA additionally for abnormality of lateral ventricles. Sequential cUS (from birth up to TEA) and MRI were classified as normal/mildly abnormal, moderately abnormal, or severely abnormal, based on a combination of findings of the WM and lateral ventricles. Predictive values of the cUS classification were calculated. Sequential cUS were classified as normal/mildly abnormal, moderately abnormal, and severely abnormal in, respectively, 22%, 65%, and 13% of infants and MRI in, respectively, 30%, 52%, and 18%. The positive predictive value of the cUS classification for the MRI classification was high for severely abnormal WM (0.79) but lower for normal/mildly abnormal (0.67) and moderately abnormal (0.64) WM. Sequential cUS during the neonatal period detects severely abnormal WM in very preterm infants but is less reliable for mildly and moderately abnormal WM. MRI around TEA seems needed to reliably detect WM injury in very preterm infants. (orig.)

  15. Nonlinear system identification in offshore structural reliability

    Spanos, P.D. [Rice Univ., Houston, TX (United States); Lu, R. [Hudson Engineering Corporation, Houston, TX (United States)


    Nonlinear forces acting on offshore structures are examined from a system identification perspective. The nonlinearities are induced by ocean waves and may become significant in many situations. They are not necessarily in the form of Morison`s equation. Various wave force models are examined. The force function is either decomposed into a set of base functions or it is expanded in terms of the wave and structural kinematics. The resulting nonlinear system is decomposed into a number of parallel no-memory nonlinear systems, each followed by a finite-memory linear system. A conditioning procedure is applied to decouple these linear sub-systems; a frequency domain technique involving autospectra and cross-spectra is employed to identify the linear transfer functions. The structural properties and those force transfer parameters are determine with the aid of the coherence functions. The method is verified using simulated data. It provides a versatile and noniterative approach for dealing with nonlinear interaction problems encountered in offshore structural analysis and design.

  16. Reliability models of belt drive systems under slipping failure mode

    Peng Gao


    Full Text Available Conventional reliability assessment and reliability-based optimal design of belt drive are based on the stress–strength interference model. However, the stress–strength interference model is essentially a static model, and the sensitivity analysis of belt drive reliability with respect to design parameters needs further investigations. In this article, time-dependent factors that contribute the dynamic characteristics of reliability are pointed out. Moreover, dynamic reliability models and failure rate models of belt drive systems under the failure mode of slipping are developed. Furthermore, dynamic sensitivity models of belt drive reliability based on the proposed dynamic reliability models are proposed. In addition, numerical examples are given to illustrate the proposed models and analyze the influences of design parameters on dynamic characteristics of reliability, failure rate, and sensitivity functions. The results show that the statistical properties of design parameters have different influences on reliability and failure rate of belt drive in cases of different values of design parameters and different operational durations.

  17. Optimal bounded control for maximizing reliability of Duhem hysteretic systems

    Ming XU; Xiaoling JIN; Yong WANG; Zhilong HUANG


    The optimal bounded control of stochastic-excited systems with Duhem hysteretic components for maximizing system reliability is investigated. The Duhem hysteretic force is transformed to energy-depending damping and stiffness by the energy dissipation balance technique. The controlled system is transformed to the equivalent non-hysteretic system. Stochastic averaging is then implemented to obtain the Itˆo stochastic equation associated with the total energy of the vibrating system, appropriate for eval-uating system responses. Dynamical programming equations for maximizing system re-liability are formulated by the dynamical programming principle. The optimal bounded control is derived from the maximization condition in the dynamical programming equa-tion. Finally, the conditional reliability function and mean time of first-passage failure of the optimal Duhem systems are numerically solved from the Kolmogorov equations. The proposed procedure is illustrated with a representative example.

  18. Reliability of a Tissue Microarray in Detecting Thyroid Transcription Factor-1 Protein in Lung Carcinomas

    Xiaoyan Bai; Hong Shen


    OBJECTIVE To compare the expression of the thyroid transcription factor-1 (TTF-1) in human normal adult type Ⅱ alveolar epithelial cells,embryonic pneumocytes and cancer cells of lung carcinoma and metastatic lymph nodes using a tissue microarray (TMA) along with paired conventional full sections.and to jnvestigate the reliability of tissue microarrays in detecting protein expression in lung carcinoma.METHODS A lung carcinoma TMA including 765 cores was constructed.TTF-1 protein expression in both TMA and paired conventional full sections were detected by yhe immunohistochemical SP method using a monoclonal antibody to TTF-1.A PU (Positive Unit) of TTF-1 protein was assessed quantitatively by the Leica Q500MC image analysis system with results from the paired conventional full sections as controls.RESULTS There was no signifcance between TMA and paired conven tional full sections in TTF-1 expression in difierent nuclei of the lung tissue.CONCLUSION TTF-1 protein expression in lung carcinoma detected by TMA was highly concordanl with that of paired full sections.TMA is a reliable method in detecting protein expression.

  19. A Method for Analyzing System Reliability of Existing Jacket Platforms

    HE Yong; GONG Shun-feng; JIN Wei-liang


    Owing to the ageing of the existing structures worldwide and the lack of codes for the continued safety management of structures during their lifetime, it is very necessary to develop a tool to evaluate their system reliability over a time interval. In this paper, a method is proposed to analyze system reliability of existing jacket platforms. The influences of dint, crack and corrosion are considered. The mechanics characteristics of the existing jacket platforms to extreme loads are analyzed by use of the nonlinear mechanical analysis. The nonlinear interaction of pile-soil-structure is taken into consideration in the analysis. By use of FEM method and Monte Carlo simulation, the system reliability of the existing jacket platform can be obtained. The method has been illustrated through application to BZ28-1 three jacket platforms which have operated for sixteen years. Advantages of the proposed method for analyzing the system reliability of the existing jacket platform is also highlighted.

  20. Bayesian approach in the power electric systems study of reliability ...

    During the applications change to all fields of engineering, the discipline has, over the years, ... Characterization of the failure rate as a random variable .... the reliability performance is defined as the conditional probability that the system ...

  1. Software reliability and safety in nuclear reactor protection systems

    Lawrence, J.D. [Lawrence Livermore National Lab., CA (United States)


    Planning the development, use and regulation of computer systems in nuclear reactor protection systems in such a way as to enhance reliability and safety is a complex issue. This report is one of a series of reports from the Computer Safety and Reliability Group, Lawrence Livermore that investigates different aspects of computer software in reactor National Laboratory, that investigates different aspects of computer software in reactor protection systems. There are two central themes in the report, First, software considerations cannot be fully understood in isolation from computer hardware and application considerations. Second, the process of engineering reliability and safety into a computer system requires activities to be carried out throughout the software life cycle. The report discusses the many activities that can be carried out during the software life cycle to improve the safety and reliability of the resulting product. The viewpoint is primarily that of the assessor, or auditor.

  2. Quantifiable and Reliable Structural Health Management Systems Project

    National Aeronautics and Space Administration — Major concerns for implementing a practical built-in structural health monitoring system are prediction accuracy and data reliability. It is proposed to develop...

  3. Allocating SMART Reliability and Maintainability Goals to NASA Ground Systems

    Gillespie, Amanda; Monaghan, Mark


    This paper will describe the methodology used to allocate Reliability and Maintainability (R&M) goals to Ground Systems Development and Operations (GSDO) subsystems currently being designed or upgraded.

  4. Lifeline system network reliability calculation based on GIS and FTA

    TANG Ai-ping; OU Jin-ping; LU Qin-nian; ZHANG Ke-xu


    Lifelines, such as pipeline, transportation, communication, electric transmission and medical rescue systems, are complicated networks that always distribute spatially over large geological and geographic units.The quantification of their reliability under an earthquake occurrence should be highly regarded, because the performance of these systems during a destructive earthquake is vital in order to estimate direct and indirect economic losses from lifeline failures, and is also related to laying out a rescue plan. The research in this paper aims to develop a new earthquake reliability calculation methodology for lifeline systems. The methodology of the network reliability for lifeline systems is based on fault tree analysis (FTA) and geological information system(GIS). The interactions existing in a lifeline system are considered herein. The lifeline systems are idealized as equivalent networks, consisting of nodes and links, and are described by network analysis in GIS. Firstly, the node is divided into two types: simple node and complicated node, where the reliability of the complicated node is calculated by FTA and interaction is regarded as one factor to affect performance of the nodes. The reliability of simple node and link is evaluated by code. Then, the reliability of the entire network is assessed based on GIS and FTA. Lastly, an illustration is given to show the methodology.

  5. The ATS F&G systems reliability program.

    Doyle, H.


    Assurance of reliability, quality, and proper testing requires a large coordinating effort and a means for connecting the various areas involved. All parts used on the spacecraft are required to meet strict specifications and consequently must be approved by the systems reliability manager. The parts program has access to a computer data bank into which all information concerning nonstandard parts approval requests has been stored. Through the data bank, the system collects and distributes timely information concerning quality and reliability to all departments that may be concerned.

  6. Software Technology for Adaptable, Reliable Systems (STARS) Technical Program Plan,


    TPP (8/06186) * SOFTWARE TECHNOLOGY IE c0 FOR r ADAPTABLE, RELIABLE SYSTEMS (STARS) TECHNICAL PROGRAM PLAN 6 AUGUST 1986 DTIC ELECTEri NOV 141986WI...NONE NONE 11. TITLE (Include Security Classification) %. Software Technology for Adaptable, Reliable Systems (STARS) Technical Program Plan 12. PERSONAL...document is the top-level technical program plan for the STARS program. It describes the objectives of the program, the technical approach to achieve

  7. Reliability Modeling of Microelectromechanical Systems Using Neural Networks

    Perera. J. Sebastian


    Microelectromechanical systems (MEMS) are a broad and rapidly expanding field that is currently receiving a great deal of attention because of the potential to significantly improve the ability to sense, analyze, and control a variety of processes, such as heating and ventilation systems, automobiles, medicine, aeronautical flight, military surveillance, weather forecasting, and space exploration. MEMS are very small and are a blend of electrical and mechanical components, with electrical and mechanical systems on one chip. This research establishes reliability estimation and prediction for MEMS devices at the conceptual design phase using neural networks. At the conceptual design phase, before devices are built and tested, traditional methods of quantifying reliability are inadequate because the device is not in existence and cannot be tested to establish the reliability distributions. A novel approach using neural networks is created to predict the overall reliability of a MEMS device based on its components and each component's attributes. The methodology begins with collecting attribute data (fabrication process, physical specifications, operating environment, property characteristics, packaging, etc.) and reliability data for many types of microengines. The data are partitioned into training data (the majority) and validation data (the remainder). A neural network is applied to the training data (both attribute and reliability); the attributes become the system inputs and reliability data (cycles to failure), the system output. After the neural network is trained with sufficient data. the validation data are used to verify the neural networks provided accurate reliability estimates. Now, the reliability of a new proposed MEMS device can be estimated by using the appropriate trained neural networks developed in this work.

  8. Operator adaptation to changes in system reliability under adaptable automation.

    Chavaillaz, Alain; Sauer, Juergen


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

  9. Final Report for the Virtual Reliability Realization System LDRD



    Current approaches to reliability are not adequate to keep pace with the need for faster, better and cheaper products and systems. This is especially true in high consequence of failure applications. The original proposal for the LDRD was to look at this challenge and see if there was a new paradigm that could make reliability predictions, along with a quantitative estimate of the risk in that prediction, in a way that was faster, better and cheaper. Such an approach would be based on the underlying science models that are the backbone of reliability predictions. The new paradigm would be implemented in two software tools: the Virtual Reliability Realization System (VRRS) and the Reliability Expert System (REX). The three-year LDRD was funded at a reduced level for the first year ($120K vs. $250K) and not renewed. Because of the reduced funding, we concentrated on the initial development of the expertise system. We developed an interactive semiconductor calculation tool needed for reliability analyses. We also were able to generate a basic functional system using Microsoft Siteserver Commerce Edition and Microsoft Sequel Server. The base system has the capability to store Office documents from multiple authors, and has the ability to track and charge for usage. The full outline of the knowledge model has been incorporated as well as examples of various types of content.

  10. Assuring long-term reliability of concentrator PV systems

    McConnell, R.; Garboushian, V.; Brown, J.; Crawford, C.; Darban, K.; Dutra, D.; Geer, S.; Ghassemian, V.; Gordon, R.; Kinsey, G.; Stone, K.; Turner, G.


    Concentrator PV (CPV) systems have attracted significant interest because these systems incorporate the world's highest efficiency solar cells and they are targeting the lowest cost production of solar electricity for the world's utility markets. Because these systems are just entering solar markets, manufacturers and customers need to assure their reliability for many years of operation. There are three general approaches for assuring CPV reliability: 1) field testing and development over many years leading to improved product designs, 2) testing to internationally accepted qualification standards (especially for new products) and 3) extended reliability tests to identify critical weaknesses in a new component or design. Amonix has been a pioneer in all three of these approaches. Amonix has an internal library of field failure data spanning over 15 years that serves as the basis for its seven generations of CPV systems. An Amonix product served as the test CPV module for the development of the world's first qualification standard completed in March 2001. Amonix staff has served on international standards development committees, such as the International Electrotechnical Commission (IEC), in support of developing CPV standards needed in today's rapidly expanding solar markets. Recently Amonix employed extended reliability test procedures to assure reliability of multijunction solar cell operation in its seventh generation high concentration PV system. This paper will discuss how these three approaches have all contributed to assuring reliability of the Amonix systems.

  11. Reliability Analysis of Structural Timber Systems

    Sørensen, John Dalsgaard; Hoffmeyer, P.


    characteristics of the load-bearing capacity is estimated in the form of a characteristic value and a coefficient of variation. These two values are of primary importance for codes of practice based on the partial safety factor format since the partial safety factor is closely related to the coefficient...... the above stochastic models, statistical characteristics (distribution function, 5% quantile and coefficient of variation) are determined. Generally, the results show that taking the system effects into account the characteristic load bearing capacity can be increased and the partial safety factor decreased...... of variation. In the paper a stochastic model is described for the strength of a single piece of timber taking into account the stochastic variation of the strength and stiffness with length. Also stochastic models for different types of loads are formulated. First, simple representative systems with different...

  12. Distribution System Reliability Analysis for Smart Grid Applications

    Aljohani, Tawfiq Masad

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

  13. Design for reliability information and computer-based systems

    Bauer, Eric


    "System reliability, availability and robustness are often not well understood by system architects, engineers and developers. They often don't understand what drives customer's availability expectations, how to frame verifiable availability/robustness requirements, how to manage and budget availability/robustness, how to methodically architect and design systems that meet robustness requirements, and so on. The book takes a very pragmatic approach of framing reliability and robustness as a functional aspect of a system so that architects, designers, developers and testers can address it as a concrete, functional attribute of a system, rather than an abstract, non-functional notion"--Provided by publisher.

  14. Site reliability engineering how Google runs production systems

    Petoff, Jennifer; Jones, Chris; Murphy, Niall Richard


    The overwhelming majority of a software system’s lifespan is spent in use, not in design or implementation. So, why does conventional wisdom insist that software engineers focus primarily on the design and development of large-scale computing systems? In this collection of essays and articles, key members of Google’s Site Reliability Team explain how and why their commitment to the entire lifecycle has enabled the company to successfully build, deploy, monitor, and maintain some of the largest software systems in the world. You’ll learn the principles and practices that enable Google engineers to make systems more scalable, reliable, and efficient—lessons directly applicable to your organization. This book is divided into four sections: Introduction—Learn what site reliability engineering is and why it differs from conventional IT industry practices Principles—Examine the patterns, behaviors, and areas of concern that influence the work of a site reliability engineer (SRE) Practices...

  15. Reliability-oriented energy storage sizing in wind power systems

    Qin, Zian; Liserre, Marco; Blaabjerg, Frede;


    Energy storage can be used to suppress the power fluctuations in wind power systems, and thereby reduce the thermal excursion and improve the reliability. Since the cost of the energy storage in large power application is high, it is crucial to have a better understanding of the relationship...... between the size of the energy storage and the reliability benefit it can generate. Therefore, a reliability-oriented energy storage sizing approach is proposed for the wind power systems, where the power, energy, cost and the control strategy of the energy storage are all taken into account....... With the proposed approach, the computational effort is reduced and the impact of the energy storage system on the reliability of the wind power converter can be quantified....

  16. SOFC Systems with Improved Reliability and Endurance

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


    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 $).

  17. Seismic reliability assessment of electric power systems

    Singhal, A. [Stanford Univ., CA (United States); Bouabid, J. [Risk Management Solutions, Menlo Park, CA (United States)


    This paper presents a methodology for the seismic risk assessment of electric power systems. In evaluating damage and loss of functionality to the electric power components, fragility curves and restoration functions are used. These vulnerability parameters are extracted from the GIS-based regional loss estimation methodology being developed for the US. Observed damage in electric power components during the Northridge earthquake is used to benchmark the methodology. The damage predicted using these vulnerability parameters is found to be in good agreement with the damage observed during the earthquake.

  18. Reliability Analysis of Random Vibration Transmission Path Systems

    Wei Zhao


    Full Text Available The vibration transmission path systems are generally composed of the vibration source, the vibration transfer path, and the vibration receiving structure. The transfer path is the medium of the vibration transmission. Moreover, the randomness of transfer path influences the transfer reliability greatly. In this paper, based on the matrix calculus, the generalized second moment technique, and the stochastic finite element theory, the effective approach for the transfer reliability of vibration transfer path systems was provided. The transfer reliability of vibration transfer path system with uncertain path parameters including path mass and path stiffness was analyzed theoretically and computed numerically, and the correlated mathematical expressions were derived. Thus, it provides the theoretical foundation for the dynamic design of vibration systems in practical project, so that most random path parameters can be considered to solve the random problems for vibration transfer path systems, which can avoid the system resonance failure.

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

    Ding, Yi; Østergaard, Jacob; Wu, Qiuwei


    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...... 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...... 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...

  20. Reliability of redundant ductile structures with uncertain system failure criteria

    Baidurya Bhattacharya; Qiang Lu; Jinquan Zhong


    Current reliability based approaches to structural design are typically element based: they commonly include uncertainties in the structural resistance, applied loads and geometric parameters, and in some cases in the idealized structural model. Nevertheless, the true measure of safety is the structural systems reliability which must consider multiple failure paths, load sharing and load redistribution after member failures, and is beyond the domain of element reliability analysis. Identification of system failure is often subjective, and a crisp definition of system failure arises naturally only in a few idealized instances equally important. We analyse the multi-girder steel highway bridge as a out of active parallel system. System failure is defined as gross inelastic deformation of the bridge deck; the subjectivity in the failure criterion is accounted for by generalizing as a random variable. Randomness in arises from a non-unique relation between number of failed girders and maximum deflection and from randomness in the definition of the failure deflection. We show how uncertain failure criteria and structural systems analyses can be decoupled. Randomness in the transverse location of trucks is considered and elastic perfectly plastic material response is assumed. The role of the system factor modifying the element-reliability based design equation to achieve a target system reliability is also demonstrated.

  1. Reliable Software Development for Machine Protection Systems

    Anderson, D; Dragu, M; Fuchsberger, K; Garnier, JC; Gorzawski, AA; Koza, M; Krol, K; Misiowiec, K; Stamos, K; Zerlauth, M


    The Controls software for the Large Hadron Collider (LHC) at CERN, with more than 150 millions lines of code, resides amongst the largest known code bases in the world1. Industry has been applying Agile software engineering techniques for more than two decades now, and the advantages of these techniques can no longer be ignored to manage the code base for large projects within the accelerator community. Furthermore, CERN is a particular environment due to the high personnel turnover and manpower limitations, where applying Agile processes can improve both, the codebase management as well as its quality. This paper presents the successful application of the Agile software development process Scrum for machine protection systems at CERN, the quality standards and infrastructure introduced together with the Agile process as well as the challenges encountered to adapt it to the CERN environment.

  2. Reliable regulation in decentralised control systems

    Locatelli, Arturo; Schiavoni, Nicola


    This article addresses the design of decentralised regulators which supply the control systems with signal tracking and disturbance rejection. This property has to be attained, to the maximum possible extent, even when instrumentation faults occur, thus causing the opening of some feedback loops. The problem is tackled for LTI asymptotically stable plants, subject to perturbations, under the assumption that the Laplace transforms of the exogenous signals have multiple poles on the imaginary axis. The proposed regulator is composed of an LTI nominal controller supervised by a reconfiguration block. Once the actions of the reconfiguration block have been settled, the synthesis of the nominal controller is reformulated as a suitable regulation problem. A constructive sufficient condition for its solvability is established. This condition turns out to be also necessary if the exogenous signals are polynomial in time.

  3. MCTSSA Software Reliability Handbook, Volume II: Data Collection Demonstration and Software Reliability Modeling for a Multi-Function Distributed System

    Schneidewind, Norman F.


    The purpose of this handbook is threefold. Specifically, it: Serves as a reference guide for implementing standard software reliability practices at Marine Corps Tactical Systems Support Activity and aids in applying the software reliability model; Serves as a tool for managing the software reliability program; and Serves as a training aid. U.S. Marine Corps Tactical Systems Support Activity, Camp Pendleton, CA. RLACH

  4. 76 FR 7187 - Priorities for Addressing Risks to the Reliability of the Bulk-Power System; Reliability...


    ... Energy Regulatory Commission Priorities for Addressing Risks to the Reliability of the Bulk- Power System; Reliability Technical Conference Panel February 2, 2011. As announced in the Notice of Technical Conference..., to discuss policy issues related to reliability of the Bulk-Power System, including priorities...

  5. Incorporating Cyber Layer Failures in Composite Power System Reliability Evaluations

    Yuqi Han


    Full Text Available This paper proposes a novel approach to analyze the impacts of cyber layer failures (i.e., protection failures and monitoring failures on the reliability evaluation of composite power systems. The reliability and availability of the cyber layer and its protection and monitoring functions with various topologies are derived based on a reliability block diagram method. The availability of the physical layer components are modified via a multi-state Markov chain model, in which the component protection and monitoring strategies, as well as the cyber layer topology, are simultaneously considered. Reliability indices of composite power systems are calculated through non-sequential Monte-Carlo simulation. Case studies demonstrate that operational reliability downgrades in cyber layer function failure situations. Moreover, protection function failures have more significant impact on the downgraded reliability than monitoring function failures do, and the reliability indices are especially sensitive to the change of the cyber layer function availability in the range from 0.95 to 1.

  6. Optimal redundancy allocation for reliability systems with imperfect switching

    Lun Ran; Jinlin Li; Xujie Jia; Hongrui Chu


    The problem of stochastical y al ocating redundant com-ponents to increase the system lifetime is an important topic of reliability. An optimal redundancy al ocation is proposed, which maximizes the expected lifetime of a reliability system with sub-systems consisting of components in paral el. The constraints are minimizing the total resources and the sizes of subsystems. In this system, each switching is independent with each other and works with probability p. Two optimization problems are studied by an incremental algorithm and dynamic programming technique respectively. The incremental algorithm proposed could obtain an approximate optimal solution, and the dynamic programming method could generate the optimal solution.

  7. Reliability modeling and analysis of smart power systems

    Karki, Rajesh; Verma, Ajit Kumar


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


    MA Xiao-ning; L(U) Zhen-zhou; YUE Zhu-feng


    An advanced reliability growth model, i. e. exponential model, was presented to estimate the model parameters for multi-systems, which was synchronously tested, synchronously censored, and synchronously improved. In the presented method,the data during the reliability growth process were taken into consideration sufficiently,including the failure numbers, safety numbers and failure time at each censored time. If the multi-systems were synchronously improved for many times, and the reliability growth of each system fitted AMSAA (Army Material Systems Analysis Activity)model, the failure time of each system could be considered rationally as an exponential distribution between two adjoining censored times. The nonparametric method was employed to obtain the reliability at each censored time of the synchronous multisystems. The point estimations of the model parameters, a and b, were given by the least square method. The confidence interval for the parameter b was given as well. An engineering illustration was used to compare the result of the presented method with those of the available models. The result shows that the presented exponential growth model fits AMSAA-BISE ( Army Material Systems Analysis Activity-Beijing Institute of Structure and Environment) model rather well, and two models are suitable to estimate the reliability growth for the synchronously developed multi-systems.

  9. Reliable Global Navigation System using Flower Constellation

    Daniele Mortari


    Full Text Available For many space missions using satellite constellations, symmetry of satellites distribution plays usually a key role. Symmetry may be considered in space and/or in time distribution. Examples of required symmetry in space distribution are in Earth observation missions (either, for local or global as well as in navigation systems. It is intuitive that to optimally observe the Earth a satellite constellation should be synchronized with the Earth rotation rate. If a satellite constellation must be designed to constitute a communication network between Earth and Jupiter, then the orbital period of the constellation satellites should be synchronized with both Earth and Jupiter periods of revolution around the Sun. Another example is to design satellite constellations to optimally observe specific Earth sites or regions. Again, this satellites constellation should be synchronized with Earth’s rotational period and (since the time gap between two subsequent observations of the site should be constant also implies time symmetry in satellites distribution. Obtaining this result will allow to design operational constellations for observing targets (sites, borders, regions with persistence or assigned revisit times, while minimizing the number of satellites required. Constellations of satellites for continuous global or zonal Earth coverage have been well studied over the last twenty years, are well known and have been well documented [1], [2], [7], [8], [11], [13]. A symmetrical, inclined constellation, such as a Walker constellation [1], [2] provides excellent global coverage for remote sensing missions; however, applications where target revisit time or persistent observation are important lead to required variations of traditional designs [7], [8]. Also, few results are available that affect other figures of merit, such as continuous regional coverage and the systematic use of eccentric orbit constellations to optimize“hang time” over regions of

  10. An Overview of the Reliability and Availability Data System (RADS)

    T. E. Wierman; K. J. Kvarfordt; S. A. Eide; D. M. Rasmuson


    The Reliability and Availability Data System (RADS) is a database and analysis code, developed by the Idaho National Engineering and Environmental Laboratory (INEEL) for the U.S. Nuclear Regulatory Commission (USNRC). The code is designed to estimate industry and plant-specific reliability and availability parameters for selected components in risk-important systems and initiating events for use in risk-informed applications. The RADS tool contains data and information based on actual operating experience from U.S. commercial nuclear power plants. The data contained in RADS is kept up-to-date by loading the most current quarter's Equipment Performance and Information Exchange (EPIX) data and by yearly lods of initiating event data from licensee event reports (LERS). The reliability parameters estimated by RADS are (1) probability of failure on demand, (2) failure rate during operation (used to calculate failure to run probability) and (3) time trends in reliability parameters.

  11. Grey System Judgment on Reliability of Mechanical Equipment


    The Grey system theory was applied in reliability analysis of mechanical equip-ment. It is a new theory and method in reliability engineering of mechanical engineering of mechanical equipment. Through the Grey forecast of reliability parameters and the relia-bility forecast of parts and systems, decisions were made in the real operative state of e-quipment in real time. It replaced the old method that required mathematics and physical statistics in a large base of test data to obtain a pre-check, and it was used in a practical problem. Because of applying the data of practical operation state in real time, it could much more approach the real condition of equipment; it was applied to guide the procedure and had rather considerable economic and social benefits.

  12. Dynamic evidential reasoning algorithm for systems reliability prediction

    Hu, Chang-Hua; Si, Xiao-Sheng; Yang, Jian-Bo


    In this article, dynamic evidential reasoning (DER) algorithm is applied to forecast reliability in turbochargers engine systems and a reliability prediction model is developed. The focus of this study is to examine the feasibility and validity of DER algorithm in systems reliability prediction by comparing it with some existing approaches. To build an effective DER forecasting model, the parameters of prediction model must be set carefully. To solve this problem, a generic nonlinear optimisation model is investigated to search for the optimal parameters of forecasting model, and then the optimal parameters are adopted to construct the DER forecasting model. Finally, a numerical example is provided to demonstrate the detailed implementation procedures and the validity of the proposed approach in the areas of reliability prediction.

  13. System Reliability Assessment of Existing Jacket Platforms in Malaysian Waters

    V.J. Kurian


    Full Text Available Reliability of offshore platforms has become a very important issue in the Malaysian Oil and Gas Industry as, majority of the jacket platforms in Malaysian waters to date, have exceeded their design life. Reliability of a jacket platform can be assessed through reliability index and probability of failure. Conventional metocean consideration uses 100 year return period wave height associated with 100 year return period current velocity and wind speed. However, recent study shows that for Malaysian waters, the proposed metocean consideration should be 100 year return period wave height associated with 10 year return period current velocity and wind speed. Hence, this research investigated the effect of different metocean consideration, to system-based reliability of jacket platforms in Malaysian waters. Prior to that, the effect of different metocean consideration to the pushover analysis has also been studied. Besides, the significance of Pile Soil Interaction (PSI, wave direction and platform geometry were analyzed in a sensitivity study. Pushover analysis was performed on three jacket platforms representing three water regions in Malaysia to obtain Reserve Strength Ratio (RSR as an indicator of the reliability of the jackets. Utilizing sensitivity study parameters mentioned above, seven different case studies were undertaken to study their significance on RSR. The RSR values of each case study were compared and incorporated as resistance model of reliability analysis. Besides, platform specific response model of each jacket has been generated using response surface technique which was later incorporated into the limit state function for reliability analysis. Reliability analysis using First Order Reliability Method (FORM has been conducted in MATLAB to obtain the reliability index and probability of failure. Results from the reliability analysis were compared to analyze the effect of different metocean consideration. In this study, an updated

  14. Tera-Op Reliable Intelligently Adaptive Processing System (TRIPS)


    AFRL-IF-WP-TR-2004-1514 TERA -OP RELIABLE INTELLIGENTLY ADAPTIVE PROCESSING SYSTEM (TRIPS) Stephen W. Keckler, Doug Burger, Michael Dahlin...03/31/2004 5a. CONTRACT NUMBER F33615-01-C-1892 5b. GRANT NUMBER 4. TITLE AND SUBTITLE TERA -OP RELIABLE INTELLIGENTLY ADAPTIVE PROCESSING...influence beyond the scope of this project; the influence is expected to increase with the fabrication of the prototype in phase 2. 1 2 Introduction The Tera

  15. Reliability analysis of large, complex systems using ASSIST

    Johnson, Sally C.


    The SURE reliability analysis program is discussed as well as the ASSIST model generation program. It is found that semi-Markov modeling using model reduction strategies with the ASSIST program can be used to accurately solve problems at least as complex as other reliability analysis tools can solve. Moreover, semi-Markov analysis provides the flexibility needed for modeling realistic fault-tolerant systems.

  16. Improving geo-information reliability by centralized change detection management

    Gorte, B.; Nardinocchi, C.; Thonon, I.; Addink, E.; Beck, R.; Persie, van M.; Kramer, H.


    A consortium called Mutatis Mutandis (MutMut), consisting of three Universities and eight producers and users of geo-information, was established in the Netherlands to streamline change detection on a national level. After preliminary investigations concerning market feasibility, three actions are

  17. Selected Methods For Increases Reliability The Of Electronic Systems Security

    Paś Jacek


    Full Text Available The article presents the issues related to the different methods to increase the reliability of electronic security systems (ESS for example, a fire alarm system (SSP. Reliability of the SSP in the descriptive sense is a property preservation capacity to implement the preset function (e.g. protection: fire airport, the port, logistics base, etc., at a certain time and under certain conditions, e.g. Environmental, despite the possible non-compliance by a specific subset of elements this system. Analyzing the available literature on the ESS-SSP is not available studies on methods to increase the reliability (several works similar topics but moving with respect to the burglary and robbery (Intrusion. Based on the analysis of the set of all paths in the system suitability of the SSP for the scenario mentioned elements fire events (device critical because of security.

  18. Reliability analysis of two unit parallel repairable industrial system

    Mohit Kumar Kakkar


    Full Text Available The aim of this work is to present a reliability and profit analysis of a two-dissimilar parallel unit system under the assumption that operative unit cannot fail after post repair inspection and replacement and there is only one repair facility. Failure and repair times of each unit are assumed to be uncorrelated. Using regenerative point technique various reliability characteristics are obtained which are useful to system designers and industrial managers. Graphical behaviors of mean time to system failure (MTSF and profit function have also been studied. In this paper, some important measures of reliability characteristics of a two non-identical unit standby system model with repair, inspection and post repair are obtained using regenerative point technique.

  19. Discrete event simulation versus conventional system reliability analysis approaches

    Kozine, Igor


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

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

    El Hami, Abdelkhalak


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

  1. Reliability assessment for components of large scale photovoltaic systems

    Ahadi, Amir; Ghadimi, Noradin; Mirabbasi, Davar


    Photovoltaic (PV) systems have significantly shifted from independent power generation systems to a large-scale grid-connected generation systems in recent years. The power output of PV systems is affected by the reliability of various components in the system. This study proposes an analytical approach to evaluate the reliability of large-scale, grid-connected PV systems. The fault tree method with an exponential probability distribution function is used to analyze the components of large-scale PV systems. The system is considered in the various sequential and parallel fault combinations in order to find all realistic ways in which the top or undesired events can occur. Additionally, it can identify areas that the planned maintenance should focus on. By monitoring the critical components of a PV system, it is possible not only to improve the reliability of the system, but also to optimize the maintenance costs. The latter is achieved by informing the operators about the system component's status. This approach can be used to ensure secure operation of the system by its flexibility in monitoring system applications. The implementation demonstrates that the proposed method is effective and efficient and can conveniently incorporate more system maintenance plans and diagnostic strategies.

  2. Recent Advances in System Reliability Signatures, Multi-state Systems and Statistical Inference

    Frenkel, Ilia


    Recent Advances in System Reliability discusses developments in modern reliability theory such as signatures, multi-state systems and statistical inference. It describes the latest achievements in these fields, and covers the application of these achievements to reliability engineering practice. The chapters cover a wide range of new theoretical subjects and have been written by leading experts in reliability theory and its applications.  The topics include: concepts and different definitions of signatures (D-spectra),  their  properties and applications  to  reliability of coherent systems and network-type structures; Lz-transform of Markov stochastic process and its application to multi-state system reliability analysis; methods for cost-reliability and cost-availability analysis of multi-state systems; optimal replacement and protection strategy; and statistical inference. Recent Advances in System Reliability presents many examples to illustrate the theoretical results. Real world multi-state systems...

  3. Simulation modeling of reliability and efficiency of mine ventilation systems

    Ushakov, V.K. (Moskovskii Gornyi Institut (USSR))


    Discusses a method developed by the MGI institute for computerized simulation of operation of ventilation systems used in deep underground coal mines. The modeling is aimed at assessment of system reliability and efficiency (probability of failure-free operation and stable air distribution). The following stages of the simulation procedure are analyzed: development of a scheme of the ventilation system (type, aerodynamic characteristics and parameters that describe system elements, e.g. ventilation tunnels, ventilation equipment, main blowers etc., dynamics of these parameters depending among others on mining and geologic conditions), development of mathematical models that describe system characteristics as well as external factors and their effects on the system, development of a structure of the simulated ventilation system, development of an algorithm, development of the final computer program for simulation of a mine ventilation system. Use of the model for forecasting reliability of air supply and efficiency of mine ventilation is discussed. 2 refs.

  4. Windfarm generation assessment for reliability analysis of power systems

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


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

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

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


    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.

  6. Reliability and validity of emergency department triage systems

    van der Wulp, I.


    Reliability and validity of triage systems is important because this can affect patient safety. In this thesis, these aspects of two emergency department (ED) triage systems were studied as well as methodological aspects in these types of studies. The consistency, reproducibility, and criterion vali

  7. Simulation methods for reliability and availability of complex systems

    Faulin Fajardo, Javier; Martorell Alsina, Sebastián Salvador; Ramirez-Marquez, Jose Emmanuel; Martorell, Sebastian


    This text discusses the use of computer simulation-based techniques and algorithms to determine reliability and/or availability levels in complex systems and to help improve these levels both at the design stage and during the system operating stage.

  8. On the reliability of a renewable multiple cold standby system

    Vanderperre E. J.


    Full Text Available We present a general reliability analysis of a renewable multiple cold standby system attended by a single repairman. Our analysis is based on a refined methodology of queuing theory. The particular case of deterministic failures provides an explicit exact result for the survival function of the duplex system.

  9. Reliability and maintainability analysis of electrical system of drum shearers

    SEYED Hadi Hoseinie; MOHAMMAD Ataei; REZA Khalokakaie; UDAY Kumar


    The reliability and maintainability of electrical system of drum shearer at Parvade.l Coal Mine in central Iran was analyzed. The maintenance and failure data were collected during 19 months of shearer operation. According to trend and serial correlation tests, the data were independent and identically distributed (iid) and therefore the statistical techniques were used for modeling. The data analysis show that the time between failures (TBF) and time to repair (TTR) data obey the lognormal and Weibull 3 parameters distribution respectively. Reliability-based preventive maintenance time intervals for electrical system of the drum shearer were calculated with regard to reliability plot. The reliability-based maintenance intervals for 90%, 80%, 70% and 50% reliability level are respectively 9.91, 17.96, 27.56 and 56.1 h. Also the calculations show that time to repair (TTR) of this system varies in range 0.17-4 h with 1.002 h as mean time to repair (MTTR). There is a 80% chance that the electrical system of shearer of Parvade.l mine repair will be accomplished within 1.45 h.

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

    I. S. Shumilov


    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

  11. Power Electronics and Reliability in Renewable Energy Systems

    Blaabjerg, Frede; Ma, Ke; Zhou, Dao


    Power Electronics are needed in almost all kind of renewable energy systems. It is used both for controlling the renewable source and also for interfacing to the load, which can be grid-connected or working in stand-alone mode. More and more efforts are put into making renewable energy systems...... better in terms of reliability in order to ensure a high availability of the power sources, in this case the knowledge of mission profile of a certain application is crucial for the reliability evaluation/design of power electronics. In this paper an overview on the power electronic circuits behind...... the most common converter configurations for wind turbine and photovoltaic is done. Next different aspects of improving the system reliability are mapped. Further on examples of how to control the chip temperature in different power electronic configurations as well as operation modes for wind power...

  12. A General Approach to Study the Reliability of Complex Systems

    G. M. Repici


    Full Text Available In recent years new complex systems have been developed in the automotive field to increase safety and comfort. These systems integrate hardware and software to guarantee the best results in vehicle handling and make products competitive on the market.However, the increase in technical details and the utilization and integration of these complicated systems require a high level of dynamic control system reliability. In order to improve this fundamental characteristic methods can be extracted from methods used in the aeronautical field to deal with reliability and these can be integrated into one simplified method for application in the automotive field.Firstly, as a case study, we decided to analyse VDC (the Vehicle Dynamics Control system by defining a possible approach to reliability techniques. A VDC Fault Tree Analysis represents the first step in this activity: FTA enables us to recognize the critical components in all possible working conditions of a car, including cranking, during 'key-on'-'key-off ' phases, which is particularly critical for the electrical on-board system (because of voltage reduction.By associating FA (Functional Analysis and FTA results with a good FFA (Functional Failure Analysis, it is possible to define the best architecture for the general system to achieve the aim of a high reliability structure.The paper will show some preliminary results from the application of this methodology, taken from various typical handling conditions from well established test procedures for vehicles.

  13. Gas Flow Detection System

    Moss, Thomas; Ihlefeld, Curtis; Slack, Barry


    This system provides a portable means to detect gas flow through a thin-walled tube without breaking into the tubing system. The flow detection system was specifically designed to detect flow through two parallel branches of a manifold with only one inlet and outlet, and is a means for verifying a space shuttle program requirement that saves time and reduces the risk of flight hardware damage compared to the current means of requirement verification. The prototype Purge Vent and Drain Window Cavity Conditioning System (PVD WCCS) Flow Detection System consists of a heater and a temperature-sensing thermistor attached to a piece of Velcro to be attached to each branch of a WCCS manifold for the duration of the requirement verification test. The heaters and thermistors are connected to a shielded cable and then to an electronics enclosure, which contains the power supplies, relays, and circuit board to provide power, signal conditioning, and control. The electronics enclosure is then connected to a commercial data acquisition box to provide analog to digital conversion as well as digital control. This data acquisition box is then connected to a commercial laptop running a custom application created using National Instruments LabVIEW. The operation of the PVD WCCS Flow Detection System consists of first attaching a heater/thermistor assembly to each of the two branches of one manifold while there is no flow through the manifold. Next, the software application running on the laptop is used to turn on the heaters and to monitor the manifold branch temperatures. When the system has reached thermal equilibrium, the software application s graphical user interface (GUI) will indicate that the branch temperatures are stable. The operator can then physically open the flow control valve to initiate the test flow of gaseous nitrogen (GN2) through the manifold. Next, the software user interface will be monitored for stable temperature indications when the system is again at

  14. Power system reliability memento; Memento de la surete du systeme electrique



    The reliability memento of the French power system (national power transmission grid) is an educational document which purpose is to point out the role of each one as regards power system operating reliability. This memento was first published in 1999. Extensive changes have taken place since then. The new 2002 edition shows that system operating reliability is as an important subject as ever: 1 - foreword; 2 - system reliability: the basics; 3 - equipment measures taken in order to guarantee the reliability of the system; 4 - organisational and human measures taken to guarantee the reliability of the system; appendix 1 - system operation: basic concepts; appendix 2 - guiding principles governing the reliability of the power system; appendix 3 - international associations of transmission system operators; appendix 4 - description of major incidents.


    P.V. Srihari


    Full Text Available Fault diagnosis of gearboxes plays an important role in increasing the availability of machinery in condition monitoring. An effort has been made in this work to develop an artificial neural networks (ANN based fault detection system to increase reliability. Two prominent fault conditions in gears, worn-out and broken teeth, are simulated and five feature parameters are extracted based on vibration signals which are used as input features to the ANN based fault detection system developed in MATLAB, a three layered feed forward network using a back propagation algorithm. This ANN system has been trained with 30 sets of data and tested with 10 sets of data. The learning rate and number of hidden layer neurons are varied individually and the optimal training parameters are found based on the number of epochs. Among the five different learning rates used the 0.15 is deduced to be optimal one and at that learning rate the number of hidden layer neurons of 9 was the optimal one out of the three values considered. Then keeping the training parameters fixed, the number of hidden layers is varied by comparing the performance of the networks and results show the two and three hidden layers have the best detection accuracy.

  16. Windfarm Generation Assessment for Reliability Analysis of Power Systems

    Barberis Negra, Nicola; Bak-Jensen, Birgitte; Holmstrøm, O.


    Due to the fast development of wind generation in the past ten years, increasing interest has been paid to techniques for assessing different aspects of power systems with a large amount of installed wind generation. One of these aspects concerns power system reliability. Windfarm modelling plays...... in a reliability model and the generation of a windfarm is evaluated by means of sequential Monte Carlo simulation. Results are used to analyse how each mentioned Factor influences the assessment, and why and when they should be included in the model....

  17. Windfarm Generation Assessment for ReliabilityAnalysis of Power Systems

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


    Due to the fast development of wind generation in the past ten years, increasing interest has been paid to techniques for assessing different aspects of power systems with a large amount of installed wind generation. One of these aspects concerns power system reliability. Windfarm modelling plays...... in a reliability model and the generation of a windfarm is evaluated by means of sequential Monte Carlo simulation. Results are used to analyse how each mentioned Factor influences the assessment, and why and when they should be included in the model....


    A. Bessarab


    All over the world safety of maintained vehicles has the major value. For motor vehicles of the Republic of Belarus this problem is also actual. Maintenance of high reliability of brake systems of cars in operation is one of ways of the decision of a problem of increase of traffic safety.The analysis of reliability of brake systems of buses MAZ is carried out following the results of the state maintenance service in 2010 and the analysis of premature returns from routes of movement of buses M...

  19. Reliable dual-redundant sensor failure detection and identification for the NASA F-8 DFBW aircraft

    Deckert, J. C.; Desai, M. N.; Deyst, J. J., Jr.; Willsky, A. S.


    A technique was developed which provides reliable failure detection and identification (FDI) for a dual redundant subset of the flight control sensors onboard the NASA F-8 digital fly by wire (DFBW) aircraft. The technique was successfully applied to simulated sensor failures on the real time F-8 digital simulator and to sensor failures injected on telemetry data from a test flight of the F-8 DFBW aircraft. For failure identification the technique utilized the analytic redundancy which exists as functional and kinematic relationships among the various quantities being measured by the different control sensor types. The technique can be used not only in a dual redundant sensor system, but also in a more highly redundant system after FDI by conventional voting techniques reduced to two the number of unfailed sensors of a particular type. In addition the technique can be easily extended to the case in which only one sensor of a particular type is available.

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

    Ivan Mavrin


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

  1. Bedside ultrasound reliability in locating catheter and detecting complications

    Payman Moharamzadeh


    Full Text Available Introduction: Central venous catheterization is one of the most common medical procedures and is associated with such complications as misplacement and pneumothorax. Chest X-ray is among good ways for evaluation of these complications. However, due to patient’s excessive exposure to radiation, time consumption and low diagnostic value in detecting pneumothorax in the supine patient, the present study intends to examine bedside ultrasound diagnostic value in locating tip of the catheter and pneumothorax. Materials and methods: In the present cross-sectional study, all referred patients requiring central venous catheterization were examined. Central venous catheterization was performed by a trained emergency medicine specialist, and the location of catheter and the presence of pneumothorax were examined and compared using two modalities of ultrasound and x-ray (as the reference standard. Sensitivity, specificity, and positive and negative predicting values were reported. Results: A total of 200 non-trauma patients were included in the study (58% men. Cohen’s Kappa consistency coefficients for catheterization and diagnosis of pneumothorax were found as 0.49 (95% CI: 0.43-0.55, 0.89 (P<0.001, (95% CI: 97.8-100, respectively. Also, ultrasound sensitivity and specificity in diagnosing pneumothorax were 75% (95% CI: 35.6-95.5, and 100% (95% CI: 97.6-100, respectively. Conclusion: The present study results showed low diagnostic value of ultrasound in determining catheter location and in detecting pneumothorax. With knowledge of previous studies, the search still on this field.   Keywords: Central venous catheterization; complications; bedside ultrasound; radiography;

  2. Reliability modeling of hydraulic system of drum shearer machine

    SEYED HADI Hoseinie; MOHAMMAD Ataie; REZA Khalookakaei; UDAY Kumar


    The hydraulic system plays an important role in supplying power and its transition to other working parts of a coal shearer machine.In this paper,the reliability of the hydraulic system of a drum shearer was analyzed.A case study was done in the Tabas Coal Mine in Iran for failure data collection.The results of the statistical analysis show that the time between failures (TBF)data of this system followed the 3-parameters Weibull distribution.There is about a 54% chance that the hydraulic system of the drum shearer will not fail for the first 50 h of operation.The developed model shows that the reliability of the hydraulic system reduces to a zero value after approximately 1 650 hours of operation.The failure rate of this system decreases when time increases.Therefore,corrective maintenance(run-to-failure)was selected as the best maintenance strategy for it.

  3. Reliability optimization of a redundant system with failure dependencies

    Yu Haiyang [Institute Charles Delaunay (ICD, FRE CNRS 2848), Troyes University of Technology, Rue Marie Curie, BP 2060, 10010 Troyes (France)]. E-mail:; Chu Chengbin [Institute Charles Delaunay (ICD, FRE CNRS 2848), Troyes University of Technology, Rue Marie Curie, BP 2060, 10010 Troyes (France); Management School, Hefei University of Technology, 193 Tunxi Road, Hefei (China); Chatelet, Eric [Institute Charles Delaunay (ICD, FRE CNRS 2848), Troyes University of Technology, Rue Marie Curie, BP 2060, 10010 Troyes (France); Yalaoui, Farouk [Institute Charles Delaunay (ICD, FRE CNRS 2848), Troyes University of Technology, Rue Marie Curie, BP 2060, 10010 Troyes (France)


    In a multi-component system, the failure of one component can reduce the system reliability in two aspects: loss of the reliability contribution of this failed component, and the reconfiguration of the system, e.g., the redistribution of the system loading. The system reconfiguration can be triggered by the component failures as well as by adding redundancies. Hence, dependency is essential for the design of a multi-component system. In this paper, we study the design of a redundant system with the consideration of a specific kind of failure dependency, i.e., the redundant dependency. The dependence function is introduced to quantify the redundant dependency. With the dependence function, the redundant dependencies are further classified as independence, weak, linear, and strong dependencies. In addition, this classification is useful in that it facilitates the optimization resolution of the system design. Finally, an example is presented to illustrate the concept of redundant dependency and its application in system design. This paper thus conveys the significance of failure dependencies in the reliability optimization of systems.

  4. Immunity Based Worm Detection System

    HONG Zheng; WU Li-fa; WANG Yuan-yuan


    Current worm detection methods are unable to detect multi-vector polymorphic worms effectively.Based on negative selection mechanism of the immune system,a local network worm detection system that detects worms was proposed.Normal network service requests were represented by self-strings,and the detection system used self-strings to monitor the network for anomaly.According to the properties of worm propagation,a control center correlated the anomalies detected in the form of binary trees to ensure the accuracy of worm detection.Experiments show the system to be effective in detecting the traditional as well as multi-vector polymorphic worms.

  5. Validity and reliability of an IMU-based method to detect APAs prior to gait initiation.

    Mancini, Martina; Chiari, Lorenzo; Holmstrom, Lars; Salarian, Arash; Horak, Fay B


    Anticipatory postural adjustments (APAs) prior to gait initiation have been largely studied in traditional, laboratory settings using force plates under the feet to characterize the displacement of the center of pressure. However clinical trials and clinical practice would benefit from a portable, inexpensive method for characterizing APAs. Therefore, the main objectives of this study were (1) to develop a novel, automatic IMU-based method to detect and characterize APAs during gait initiation and (2) to measure its test-retest reliability. Experiment I was carried out in the laboratory to determine the validity of the IMU-based method in 10 subjects with PD (OFF medication) and 12 control subjects. Experiment II was carried out in the clinic, to determine test-retest reliability of the IMU-based method in a different set of 17 early-to-moderate, treated subjects with PD (tested ON medication) and 17 age-matched control subjects. Results showed that gait initiation characteristics (both APAs and 1st step) detected with our novel method were significantly correlated to the characteristics calculated with a force plate and motion analysis system. The size of APAs measured with either inertial sensors or force plate was significantly smaller in subjects with PD than in control subjects (p<0.05). Test-retest reliability for the gait initiation characteristics measured with inertial sensors was moderate-to-excellent (0.56

  6. Effective Measurement of Reliability of Repairable USAF Systems


    Hansen presented a course, Concepts and Models for Repairable Systems Reliability, at the 2009 Centro de Investigacion en Mathematicas (CIMAT). The...defines MTBF in Technical Order 00-2-2, Maintenance Documentation ., Mean Time Between Failure (Inherent). Inherent refers to a Type 1 failure or...The USAF uses maintenance data to document the system failures. There is no method within that data system to define specific failure modes

  7. Availability, reliability and downtime of systems with repairable components

    Kiureghian, Armen Der; Ditlevsen, Ove Dalager; Song, J.


    Closed-form expressions are derived for the steady-state availability, mean rate of failure, mean duration of downtime and lower bound reliability of a general system with randomly and independently failing repairable components. Component failures are assumed to be homogeneous Poisson events in ......, or reducing the mean duration of system downtime. Example applications to an electrical substation system demonstrate the use of the formulas developed in the paper....

  8. Power system reliability enhancement by using PowerformerTM

    Rahmat-Allah Hooshmand


    Full Text Available A high-voltage generator PowerformerTM is a new generation of the AC generators. The most significant advantages of these PowerformerTM are their direct connection to high-voltage grid, higher availability, and more reactive power margin, short term overloading capacity and removing the power transformer from the structure of the power plant. In this paper, the installation effect of these generators on the power system reliability is investigated. The amount of the effects depends on the type and location of the power plant, location of the PowerformerTM, the size of load and network topology. For this purpose, in the 6-bus IEEE RBTS system, the conventional generators are replaced by these new PowerformerTM and then, the reliability indices are evaluated. The simulation results show that the reliability indices such as the expected duration of load curtailment (EDLC and the expected energy not served (EENS are improved. .

  9. The Development of a Demonstration Passive System Reliability Assessment

    Bucknor, Matthew; Grabaskas, David; Brunett, Acacia


    In this paper, the details of the development of a demonstration problem to assess the reliability of a passive safety system are presented. An advanced small modular reactor (advSMR) design, which is a pool-type sodium fast reactor (SFR) coupled with a passive reactor cavity cooling system (RCCS) is described. The RELAP5-3D models of the advSMR and RCCS that will be used to simulate a long-term station blackout (SBO) accident scenario are presented. Proposed benchmarking techniques for both the reactor and the RCCS are discussed, which includes utilization of experimental results from the Natural convection Shutdown heat removal Test Facility (NSTF) at the Argonne National Laboratory. Details of how mechanistic methods, specifically the Reliability Method for Passive Systems (RMPS) approach, will be utilized to determine passive system reliability are presented. The results of this mechanistic analysis will ultimately be compared to results from dynamic methods in future work. This work is part of an ongoing project at Argonne to demonstrate methodologies for assessing passive system reliability.

  10. Generating function approach to reliability analysis of structural systems


    The generating function approach is an important tool for performance assessment in multi-state systems. Aiming at strength reliability analysis of structural systems, generating function approach is introduced and developed. Static reliability models of statically determinate, indeterminate systems and fatigue reliability models are built by constructing special generating functions, which are used to describe probability distributions of strength (resistance), stress (load) and fatigue life, by defining composite operators of generating functions and performance structure functions thereof. When composition operators are executed, computational costs can be reduced by a big margin by means of collecting like terms. The results of theoretical analysis and numerical simulation show that the generating function approach can be widely used for probability modeling of large complex systems with hierarchical structures due to the unified form, compact expression, computer program realizability and high universality. Because the new method considers twin loads giving rise to component failure dependency, it can provide a theoretical reference and act as a powerful tool for static, dynamic reliability analysis in civil engineering structures and mechanical equipment systems with multi-mode damage coupling.



    The optimum design method based on the reliability is presented to the stochastic structure systems (i. e., the sectional area, length, elastic module and strength of the structural member are random variables) under the random loads. The sensitivity expression of system reliability index and the safety margins were presented in the stochastic structure systems. The optimum vector method was given. First, the expressions of the reliability index of the safety margins with the improved first-order second-moment and the stochastic finite element method were deduced, and then the expressions of the systemic failure probability by probabilistic network evaluation technique(PNET) method were obtained. After derivation calculus, the expressions of the sensitivity analysis for the system reliability were obtained. Moreover, the optimum design with the optimum vector algorithm was undertaken. In the optimum iterative procedure, the gradient step and the optimum vector step were adopted to calculate. At the last, a numerical example was provided to illustrate that the method is efficient in the calculation, stably converges and fits the application in engineering.

  12. Assuring Quality and Reliability in Complex Avionics Systems hardware & Software

    V. Haridas


    Full Text Available It is conventional wisdom in defence systems that electronic brains are where much of the present and future weapons system capability is developed. Electronic hardware advances, particularly in microprocessor, allow highly complex and sophisticated software to provide high degree of system autonomy and customisation to mission at hand. Since modern military systems are so much dependent on the proper functioning of electronics, the quality and reliability of electronic hardware and software have a profound impact on defensive capability and readiness. At the hardware level, due to the advances in microelectronics, functional capabilities of today's systems have increased. The advances in the hardware field have an impact on software also. Now a days, it is possible to incorporate more and more system functions through software, rather than going for a pure hardware solution. On the other hand complexities the systems are increasing, working energy levels of the systems are decreasing and the areas of reliability and quality assurance are becoming more and more wide. This paper covers major failure modes in microelectronic devices. The various techniques used to improve component and system reliability are described. The recent trends in expanding the scope of traditional quality assurance techniques are also discussed, considering both hardware and software.

  13. Highly Sensitive and Reliable Detection of EGFR Exon 19 Deletions by Droplet Digital Polymerase Chain Reaction.

    Oskina, Natalya; Oscorbin, Igor; Khrapov, Evgeniy; Boyarskikh, Ulyana; Subbotin, Dmitriy; Demidova, Irina; Imyanitov, Evgeny; Filipenko, Maxim


    Analysis of EGFR mutations is becoming a routine clinical practice but the optimal EGFR mutation testing method is still to be determined. We determined the nucleotide sequence of deletions located in exon 19 of the EGFR gene in lung tumor samples of patients residing in different regions of Russia (153 tumor DNA specimens), using Sanger sequencing. We developed a droplet digital polymerase chain reaction assay capable of detecting all common EGFR deletions in exon 19. We also compared the therascreen amplification refractory mutation system assay with a droplet digital polymerase chain reaction assay for the detection of all the deletions in our study. The droplet digital polymerase chain reaction assay demonstrated 100% sensitivity against polymerase chain reaction fragment length analysis and detected all possible types of deletions revealed in our study (22 types). At the same time, the therascreen EGFR RGQ PCR Kit was not able to detect deletions c.2252-2276>A and c.2253-2276 and showed low performance for another long deletion. Thus, we can conclude that the extraordinary length of deletions and their atypical locations (shift at the 3'-region compared to known deletions) could be problematic for the therascreen EGFR RGQ PCR Kit and should be taken into account during targeted mutation test development. However, droplet digital polymerase chain reaction is a promising and reliable assay that can be used as a diagnostic tool to genotype formalin-fixed paraffin-embedded cancer samples for EGFR or another clinically relevant somatic mutation.

  14. Modelling Reliability-adaptive Multi-system Operation

    Uwe K. Rakowsky


    This contribution discusses the concept of Reliability-Adaptive Systems (RAS) to multi-system operation. A fleet of independently operating systems and a single maintenance unit are considered. It is the objective in this paper to increase overall performance or workload respectively by avoiding delay due to busy maintenance units. This is achieved by concerted and coordinated derating of individual system performance, which increases reliability. Quantification is carried out by way of a convolution-based approach. The approach is tailored to fleets of ships, aeroplanes, spacecraft, and vehicles (trains, trams, buses, cars, trucks, etc.) - Finally, the effectiveness of derating is validated using different criteria. The RAS concept makes sense if average system output loss due to lowered performance level (yielding longer time to failure) is smaller than average loss due to waiting for maintenance in a non-adaptive case.

  15. Automated Energy Distribution and Reliability System Status Report

    Buche, D. L.; Perry, S.


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

  16. Reliability analysis of flood defence systems in the Netherlands

    Lassing, B.L.; Vrouwenvelder, A.C.W.M.; Waarts, P.H.


    In recent years an advanced program for reliability analysis of dike systems has been under de-velopment in the Netherlands. This paper describes the global data requirements for application and the set-up of the models in the Netherlands. The analysis generates an estimate of the probability of sys

  17. Importance Sampling Simulations of Markovian Reliability Systems using Cross Entropy

    Ridder, Ad


    This paper reports simulation experiments, applying the cross entropy method suchas the importance sampling algorithm for efficient estimation of rare event probabilities in Markovian reliability systems. The method is compared to various failurebiasing schemes that have been proved to give estimato

  18. Importance Sampling Simulations of Markovian Reliability Systems using Cross Entropy

    Ridder, Ad


    This paper reports simulation experiments, applying the cross entropy method suchas the importance sampling algorithm for efficient estimation of rare event probabilities in Markovian reliability systems. The method is compared to various failurebiasing schemes that have been proved to give estimato

  19. Reliability-Based Inspection Planning for Structural Systems

    Sørensen, John Dalsgaard


    A general model for reliability-based optimal inspection and repair strategies for structural systems is described. The total expected costs in the design lifetime is minimized with the number of inspections, the inspection times and efforts as decision variables. The equivalence of this model wi...

  20. Automated Energy Distribution and Reliability System (AEDR): Final Report

    Buche, D. L.


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

  1. Reliability and predictors of resistive load detection in children with persistent asthma: a multivariate approach.

    Harver, Andrew; Dyer, Allison; Ersek, Jennifer L; Kotses, Harry; Humphries, C Thomas


    Resistive load detection tasks enable analysis of individual differences in psychophysical outcomes. The purpose of this study was to determine both the reliability and predictors of resistive load detection in children with persistent asthma who completed multiple testing sessions. Both University of North Carolina (UNC) Charlotte and Ohio University institutional review boards approved the research protocol. The detection of inspiratory resistive loads was evaluated in 75 children with asthma between 8 and 15 years of age. Each child participated in four experimental sessions that occurred approximately once every 2 weeks. Multivariate analyses were used to delineate predictors of task performance. Reliability of resistive load detection was determined for each child, and predictors of load detection outcomes were investigated in two groups of children: those who performed reliably in all four sessions (n = 31) and those who performed reliably in three or fewer sessions (n = 44). Three factors (development, symptoms, and compliance) accounted for 66.3% of the variance among variables that predicted 38.7% of the variance in load detection outcomes (Multiple R = 0.62, p = 0.004) and correctly classified performance as reliable or less reliable in 80.6% of the children, χ(2)(12) = 28.88, p = 0.004. Cognitive and physical development, appraisal of symptom experiences, and adherence-related behaviors (1) account for a significant proportion of the interrelationships among variables that affect perception of airflow obstruction in children with asthma and (2) differentiate between children who perform more or less reliably in a resistive load detection task.

  2. Reliability of decision-support systems for nuclear emergency management

    Ionescu, Tudor B.


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

  3. Social sensing building reliable systems on unreliable data

    Wang, Dong; Kaplan, Lance


    Increasingly, human beings are sensors engaging directly with the mobile Internet. Individuals can now share real-time experiences at an unprecedented scale. Social Sensing: Building Reliable Systems on Unreliable Data looks at recent advances in the emerging field of social sensing, emphasizing the key problem faced by application designers: how to extract reliable information from data collected from largely unknown and possibly unreliable sources. The book explains how a myriad of societal applications can be derived from this massive amount of data collected and shared by average individu

  4. On the reliability of Quake-Catcher Network earthquake detections

    Yildirim, Battalgazi; Cochran, Elizabeth S.; Chung, Angela I.; Christensen, Carl M.; Lawrence, Jesse F.


    Over the past two decades, there have been several initiatives to create volunteer‐based seismic networks. The Personal Seismic Network, proposed around 1990, used a short‐period seismograph to record earthquake waveforms using existing phone lines (Cranswick and Banfill, 1990; Cranswicket al., 1993). NetQuakes (Luetgert et al., 2010) deploys triaxial Micro‐Electromechanical Systems (MEMS) sensors in private homes, businesses, and public buildings where there is an Internet connection. Other seismic networks using a dense array of low‐cost MEMS sensors are the Community Seismic Network (Clayton et al., 2012; Kohler et al., 2013) and the Home Seismometer Network (Horiuchi et al., 2009). One main advantage of combining low‐cost MEMS sensors and existing Internet connection in public and private buildings over the traditional networks is the reduction in installation and maintenance costs (Koide et al., 2006). In doing so, it is possible to create a dense seismic network for a fraction of the cost of traditional seismic networks (D’Alessandro and D’Anna, 2013; D’Alessandro, 2014; D’Alessandro et al., 2014).

  5. Reliability of emergency ac power systems at nuclear power plants

    Battle, R E; Campbell, D J


    Reliability of emergency onsite ac power systems at nuclear power plants has been questioned within the Nuclear Regulatory Commission (NRC) because of the number of diesel generator failures reported by nuclear plant licensees and the reactor core damage that could result from diesel failure during an emergency. This report contains the results of a reliability analysis of the onsite ac power system, and it uses the results of a separate analysis of offsite power systems to calculate the expected frequency of station blackout. Included is a design and operating experience review. Eighteen plants representative of typical onsite ac power systems and ten generic designs were selected to be modeled by fault trees. Operating experience data were collected from the NRC files and from nuclear plant licensee responses to a questionnaire sent out for this project.


    G. Sankaraiah


    Full Text Available

    ENGLISH ABSTRACT: The reliability of a system is generally treated as a function of cost; but in many real-life situations reliability will depend on a variety of factors. It is therefore interesting to probe the hidden impact of constraints apart from cost – such as weight, volume, and space. This paper attempts to study the impact of multiple constraints on system reliability. For the purposes of analysis, an integrated redundant reliability system is considered, modelled and solved by applying a Lagrangian multiplier that gives a real valued solution for the number of components, for its reliability at each stage, and for the system. The problem is further studied by using a heuristic algorithm and an integer programming method, and is validated by sensitivity analysis to present an integer solution.

    AFRIKAANSE OPSOMMING: Die betroubaarheid van ‘n sisteem word normaalweg as ‘n funksie van koste beskou, alhoewel dit in baie gevalle afhang van ‘n verskeidenheid faktore. Dit is dus interessant om die verskuilde impak van randvoorwaardes soos massa, volume en ruimte te ondersoek. Hierdie artikel poog om die impak van meervoudige randvoorwaardes op sisteem-betroubaarheid te bestudeer. Vir die ontleding, word ‘n geïntegreerde betroubaarheid-sisteem met oortolligheid beskou, gemodelleer en opgelos aan die hand van ‘n Lagrange-vermenigvuldiger. Die problem word verder bestudeer deur gebruik te maak van ‘n heuristiese algoritme en heeltalprogrammering asook gevalideer by wyse van ‘n sensitiwiteitsanalise sodat ‘n heeltaloplossing voorgehou kan word.

  7. Reliability Assessment of IGBT Modules Modeled as Systems with Correlated Components

    Kostandyan, Erik; Sørensen, John Dalsgaard


    configuration. The estimated system reliability by the proposed method is a conservative estimate. Application of the suggested method could be extended for reliability estimation of systems composing of welding joints, bolts, bearings, etc. The reliability model incorporates the correlation between...

  8. Systems astrobiology for a reliable biomarker on exo-worlds

    Chela Flores, Julian


    Although astrobiology is a science midway between biology and astrophysics, it has surprisingly remained largely disconnected from recent trends in certain branches of both of these disciplines. Aiming at discovering how systems properties emerge has proved valuable in chemistry and in biology and should also yield insights into astrobiology. This is feasible since new large data banks in the case of astrobiology are of a geophysical/astronomical kind, rather than the also large molecular biology data that are used for questions related firstly, to genetics in a systems context and secondly, to biochemistry. The application of systems biology is illustrated for our own planetary system, where 3 Earth-like planets are within the habitable zone of a G2V star and where the process of photosynthesis has led to a single oxygenic atmosphere that was triggered during the Great Oxidation Event some 2,5 billion years before the present. The significance of the biogenic origin of a considerable fraction of our atmosphere has been discussed earlier (Kiang et al., 2007). Bonding of O2 ensures that it is stable enough to accumulate in a world's atmosphere if triggered by a living process. The reduction of F and Cl deliver energy release per e+-transfer, but unlike O2 the weaker bonding properties inhibit large atmospheric accumulation (Catling et al., 2005). The evolution of O2-producing photosynthesis is very likely on exo-worlds (Wolstencroft and Raven, 2002). With our simplifying assumption of evolutionary convergence, we show how to probe for a reliable biomarker in the exo-atmospheres of planets, or their satellites, orbiting stars of different luminosities and ages (Chela-Flores, 2013). We treat the living process as a system of exo-environments capable of radically modifying their geology and atmospheres, both for exo-planets, and especially for exo-moons, the presence of which can be extracted from the Kepler data (Kipping et al., 2012). What we are learning about the

  9. Practical reliability and uncertainty quantification in complex systems : final report.

    Grace, Matthew D.; Ringland, James T.; Marzouk, Youssef M. (Massachusetts Institute of Technology, Cambridge, MA); Boggs, Paul T.; Zurn, Rena M.; Diegert, Kathleen V. (Sandia National Laboratories, Albuquerque, NM); Pebay, Philippe Pierre; Red-Horse, John Robert (Sandia National Laboratories, Albuquerque, NM)


    The purpose of this project was to investigate the use of Bayesian methods for the estimation of the reliability of complex systems. The goals were to find methods for dealing with continuous data, rather than simple pass/fail data; to avoid assumptions of specific probability distributions, especially Gaussian, or normal, distributions; to compute not only an estimate of the reliability of the system, but also a measure of the confidence in that estimate; to develop procedures to address time-dependent or aging aspects in such systems, and to use these models and results to derive optimal testing strategies. The system is assumed to be a system of systems, i.e., a system with discrete components that are themselves systems. Furthermore, the system is 'engineered' in the sense that each node is designed to do something and that we have a mathematical description of that process. In the time-dependent case, the assumption is that we have a general, nonlinear, time-dependent function describing the process. The major results of the project are described in this report. In summary, we developed a sophisticated mathematical framework based on modern probability theory and Bayesian analysis. This framework encompasses all aspects of epistemic uncertainty and easily incorporates steady-state and time-dependent systems. Based on Markov chain, Monte Carlo methods, we devised a computational strategy for general probability density estimation in the steady-state case. This enabled us to compute a distribution of the reliability from which many questions, including confidence, could be addressed. We then extended this to the time domain and implemented procedures to estimate the reliability over time, including the use of the method to predict the reliability at a future time. Finally, we used certain aspects of Bayesian decision analysis to create a novel method for determining an optimal testing strategy, e.g., we can estimate the 'best' location to

  10. Reliability study of complex physical systems using SysML

    David, Pierre, E-mail: pierre.david@ensi-bourges.f [Institut PRISME - ENSIB, 88 Boulevard Lahitolle, 18020 Bourges Cedex (France); Idasiak, Vincent, E-mail: vincent.idasiak@ensi-bourges.f [Institut PRISME - ENSIB, 88 Boulevard Lahitolle, 18020 Bourges Cedex (France); Kratz, Frederic, E-mail: frederic.kratz@ensi-bourges.f [Institut PRISME - ENSIB, 88 Boulevard Lahitolle, 18020 Bourges Cedex (France)


    The development of safety critical systems becomes even harder since the complexity of these systems grows continuously. Moreover, this kind of process involves the use of powerful design methods and precise reliability techniques that utilize dissimilar models and construction policy. In this article we propose a method to unify and enhance this process by linking functional design phase using SysML with commonly used reliability techniques such as FMEA and dysfunctional models construction in AltaRica Data Flow. We present how SysML models can be analyzed automatically in order to produce an FMEA and expose a parallel between SysML models and AltaRica Data Flow ones. The given approach is structured around a database of dysfunctional behaviors that supports the studies and is updated by the obtained results. We exemplify the approach to analyze a system of level controlling of a tank.


    A. Bessarab


    Full Text Available All over the world safety of maintained vehicles has the major value. For motor vehicles of the Republic of Belarus this problem is also actual. Maintenance of high reliability of brake systems of cars in operation is one of ways of the decision of a problem of increase of traffic safety.The analysis of reliability of brake systems of buses MAZ is carried out following the results of the state maintenance service in 2010 and the analysis of premature returns from routes of movement of buses MAZ-103 and МАZ-104 one of the motor transportation enterprises of a city of Minsk. Principal causes of structural parameters modification of brake pneumatic system of buses, the brake mechanism and elements АBS are considered.


    A.C. Rooney


    Full Text Available

    ENGLISH ABSTRACT: This paper proposes a reliability management process for the development of complex electromechanical systems. Specific emphasis is the development of these systems in an environment of limited development resources, and where small production quantities are envisaged.
    The results of this research provides a management strategy for reliability engineering activities, within a systems engineering environment, where concurrent engineering techniques are used to reduce development cycles and costs.

    AFRIKAANSE OPSOMMING: Hierdie artikel stel 'n proses, vir die bestuur van die betroubaarheid gedurende die ontwikkeling van komplekse elektromeganiese stelsels voor. Die omgewing van beperkte ontwikkelingshulpbronne en klein produksie hoeveelhede word beklemtoon.
    Die resultate van hierdie navorsing stel 'n bestuurstrategie, vir betroubaarheidsbestuur in n stelselsingenieurswese omgewing waar gelyktydige ingenieurswese tegnieke gebruik word am die ontwikkelingsiklus en -kostes te beperk, voor.

  13. Offshore compression system design for low cost high and reliability

    Castro, Carlos J. Rocha de O.; Carrijo Neto, Antonio Dias; Cordeiro, Alexandre Franca [Chemtech Engineering Services and Software Ltd., Rio de Janeiro, RJ (Brazil). Special Projects Div.], Emails:,,


    In the offshore oil fields, the oil streams coming from the wells usually have significant amounts of gas. This gas is separated at low pressure and has to be compressed to the export pipeline pressure, usually at high pressure to reduce the needed diameter of the pipelines. In the past, this gases where flared, but nowadays there are a increasing pressure for the energy efficiency improvement of the oil rigs and the use of this gaseous fraction. The most expensive equipment of this kind of plant are the compression and power generation systems, being the second a strong function of the first, because the most power consuming equipment are the compressors. For this reason, the optimization of the compression system in terms of efficiency and cost are determinant to the plant profit. The availability of the plants also have a strong influence in the plant profit, specially in gas fields where the products have a relatively low aggregated value, compared to oil. Due this, the third design variable of the compression system becomes the reliability. As high the reliability, larger will be the plant production. The main ways to improve the reliability of compression system are the use of multiple compression trains in parallel, in a 2x50% or 3x50% configuration, with one in stand-by. Such configurations are possible and have some advantages and disadvantages, but the main side effect is the increase of the cost. This is the offshore common practice, but that does not always significantly improve the plant availability, depending of the previous process system. A series arrangement and a critical evaluation of the overall system in some cases can provide a cheaper system with equal or better performance. This paper shows a case study of the procedure to evaluate a compression system design to improve the reliability but without extreme cost increase, balancing the number of equipment, the series or parallel arrangement, and the driver selection. Two cases studies will be

  14. Turbine Reliability and Operability Optimization through the use of Direct Detection Lidar Final Technical Report

    Johnson, David K; Lewis, Matthew J; Pavlich, Jane C; Wright, Alan D; Johnson, Kathryn E; Pace, Andrew M


    The goal of this Department of Energy (DOE) project is to increase wind turbine efficiency and reliability with the use of a Light Detection and Ranging (LIDAR) system. The LIDAR provides wind speed and direction data that can be used to help mitigate the fatigue stress on the turbine blades and internal components caused by wind gusts, sub-optimal pointing and reactionary speed or RPM changes. This effort will have a significant impact on the operation and maintenance costs of turbines across the industry. During the course of the project, Michigan Aerospace Corporation (MAC) modified and tested a prototype direct detection wind LIDAR instrument; the resulting LIDAR design considered all aspects of wind turbine LIDAR operation from mounting, assembly, and environmental operating conditions to laser safety. Additionally, in co-operation with our partners, the National Renewable Energy Lab and the Colorado School of Mines, progress was made in LIDAR performance modeling as well as LIDAR feed forward control system modeling and simulation. The results of this investigation showed that using LIDAR measurements to change between baseline and extreme event controllers in a switching architecture can reduce damage equivalent loads on blades and tower, and produce higher mean power output due to fewer overspeed events. This DOE project has led to continued venture capital investment and engagement with leading turbine OEMs, wind farm developers, and wind farm owner/operators.

  15. Design for Verification: Using Design Patterns to Build Reliable Systems

    Mehlitz, Peter C.; Penix, John; Koga, Dennis (Technical Monitor)


    Components so far have been mainly used in commercial software development to reduce time to market. While some effort has been spent on formal aspects of components, most of this was done in the context of programming language or operating system framework integration. As a consequence, increased reliability of composed systems is mainly regarded as a side effect of a more rigid testing of pre-fabricated components. In contrast to this, Design for Verification (D4V) puts the focus on component specific property guarantees, which are used to design systems with high reliability requirements. D4V components are domain specific design pattern instances with well-defined property guarantees and usage rules, which are suitable for automatic verification. The guaranteed properties are explicitly used to select components according to key system requirements. The D4V hypothesis is that the same general architecture and design principles leading to good modularity, extensibility and complexity/functionality ratio can be adapted to overcome some of the limitations of conventional reliability assurance measures, such as too large a state space or too many execution paths.

  16. Optimal reliability design method for remote solar systems

    Suwapaet, Nuchida

    A unique optimal reliability design algorithm is developed for remote communication systems. The algorithm deals with either minimizing an unavailability of the system within a fixed cost or minimizing the cost of the system with an unavailability constraint. The unavailability of the system is a function of three possible failure occurrences: individual component breakdown, solar energy deficiency (loss of load probability), and satellite/radio transmission loss. The three mathematical models of component failure, solar power failure, transmission failure are combined and formulated as a nonlinear programming optimization problem with binary decision variables, such as number and type (or size) of photovoltaic modules, batteries, radios, antennas, and controllers. Three possible failures are identified and integrated in computer algorithm to generate the parameters for the optimization algorithm. The optimization algorithm is implemented with a branch-and-bound technique solution in MS Excel Solver. The algorithm is applied to a case study design for an actual system that will be set up in remote mountainous areas of Peru. The automated algorithm is verified with independent calculations. The optimal results from minimizing the unavailability of the system with the cost constraint case and minimizing the total cost of the system with the unavailability constraint case are consistent with each other. The tradeoff feature in the algorithm allows designers to observe results of 'what-if' scenarios of relaxing constraint bounds, thus obtaining the most benefit from the optimization process. An example of this approach applied to an existing communication system in the Andes shows dramatic improvement in reliability for little increase in cost. The algorithm is a real design tool, unlike other existing simulation design tools. The algorithm should be useful for other stochastic systems where component reliability, random supply and demand, and communication are

  17. Reliability Analysis of Penetration Systems Using Nondeterministic Methods



    Device penetration into media such as metal and soil is an application of some engineering interest. Often, these devices contain internal components and it is of paramount importance that all significant components survive the severe environment that accompanies the penetration event. In addition, the system must be robust to perturbations in its operating environment, some of which exhibit behavior which can only be quantified to within some level of uncertainty. In the analysis discussed herein, methods to address the reliability of internal components for a specific application system are discussed. The shock response spectrum (SRS) is utilized in conjunction with the Advanced Mean Value (AMV) and Response Surface methods to make probabilistic statements regarding the predicted reliability of internal components. Monte Carlo simulation methods are also explored.


    Grigorash O. V.


    Full Text Available The level of technical development today requires the creation of highly effective, including reliable, uninter-rupted power supply systems. We have shown modern requirements and design features of modern systems of uninterruptible power supply, which should be built on a modular principle. It is shown that the problem of synthesis of systems in a modular approach is addressing three issues: development of the structure of the system subject to the requirements of consumers to quality of power and the allowable time of power outage; determining the required level redundancy of major functional units (blocks, elements to ensure the required reliability of the system; - ensuring the most effective interconnection of modules, including electromagnetic compatibility, and the rational use during normal and emergency operation of the system. We have proposed new structural solution of the main functional units and uninterrupted power supply systems in modular design. To reduce EMI and improve efficiency uninterruptible power supply systems in the design of static converters we need to use a transformer with a rotating magnetic field. In addition, the prospective current is to be used as a source of renewable energy. Another promising approach is the use of direct frequency converters as voltage stabilizers and frequency of the current

  19. Link Reliability based Detection and Predecessor base Route Establishment for Prevention of Wormhole Attack

    Nansi Jain


    Full Text Available Mobile Ad hoc Network (MANET is consists of mobile hosts or sensor nodes proficient of functioning in absence of infrastructure. Such networks should be capable of self forming, self organizing, self managing, self recovering, and able to operate under dynamic conditions. The multi-hop communication phenomenon is used to sending information to receiver. To attain this, each mobile node depends on its neighbor or range node to forward the data packet to the destination. In fact, most of previous studies on MANET have implicitly assumed that nodes are cooperative such as node cooperation becomes a very important issue in MANET. The attacker in dynamic network are easily affected the routing performance and data receiving ratio is affected as compared to normal performance of network as well as dropping of data is enhanced. The packets percentage is degrades is the confirmation of attacker misbehavior. The characteristics of wormhole attack is to making the tunnel and reply the positive acknowledgement of destination at time of route request and drop all the data deliver through tunnel. The attacker is identified by the past and current data receiving and forwarding in MANET. The proposed IPS (Intrusion Detection and Prevention System provides the security on the basis of link reliability. In this work, we proposed new link reliability based security through Predecessor based Route Establishment of detecting routing misbehavior of wormhole attack for prevention in MANET. The attacker is blocked through the broadcasting scheme used by proposed prevention scheme from their actual identification to neighbors. The security provider nodes are blocking the communication of attacker and provide the secure communication among the mobile nodes. The performance of proposed scheme is evaluated through performance metrics like PDR and throughput




    Full Text Available The paper has three parts, in the first one, is presented the theoretical concepts that refer on the grounding lines fault, the treating mode, and implemented solutions for their detection in electric stations. In the second part is presented the result of the operational reliability analyse in period of 2011 – 2015, as in the final part of the paper are given the conclusions and identified solutions regarding the improving of operational reliability of the protection equipment of detection of grounding lines.

  1. Workload, Performance and Reliability of Digital Computing Systems.


    Proschan. Mathematical Theory of Reliability. John Wiley & Sons, 1965. [ Bazaraa 79] M.S. Bazaraa and C.M. Shetty. Nonlinear Programming. Theory and...exercised. System software failures are due to: a) the (static) input data to a progam module presents some peculiarities that the program is not able of...available, this is a typical nonlinear programming problem, subject to nonlinear inequality constraints. Since this problem will have to be solved

  2. 基于环结构的可靠检测机制%Reliable detection mechanism based on ring structure

    李俊锋; 杨英杰; 张国强


    为了解决层次式失效检测方法中检测点单点失效问题,为系统提供一种可靠检测点,提出基于环结构的可靠检测机制(BR_RD).该机制采用环检测算法迅速发现可疑失效节点,利用随机半元确认算法定位出环内的失效节点,通过选举算法产生新的可靠节点来替代失效节点以保持环结构完整性.其有效性和可靠性在失效注入实验中得到验证.%To solve the single failure point in hierarchical failure detection model and supply a reliable detecting point for the detection system, reliable detection mechanism based on ring structure (BR_ RD) is presented, which consists of multiple points. The loop detection algorithm is to find suspect failure points, then random semi-confirmation algorithm is to locate the failure points in the ring, and election algorithm is to maintenance the integrity of the ring structure by updating the failed points. Its validity and reliability is verified by failure injection experiments.

  3. Reliability Assessment of Distribution System Based on Discrete-event System

    丁屹峰; 程浩忠; 陈春霖; 江峰青; 房龄峰


    Discrete-event system simulation technology is used to analyze distribution system reliability in this paper. A simulation model, including entity state models, system state models, state transition models, reliability criterion model, is ciple of simulator clock to determine the sequence of random event occurrence dynamically. The results show this method is feasible.

  4. Implementation of Reliable Open Source IRIS Recognition System

    Dhananjay Ikhar


    Full Text Available RELIABLE automatic recognition of persons has long been an attractive goal. As in all pattern recognition problems, the key issue is the relation between inter-class and intra-class variability: objects can be reliably classified only if the variability among different instances of a given class is less than the variability between different classes.The objective of this paper is to implement an open-source iris recognition system in order to verify the claimed performance of the technology. The development tool used will be MATLAB, and emphasis will be only on the software for performing recognition and not hardware for capturing an eye image. A reliable application development approach will be employed in order to produce results quickly. MATLAB provides an excellent environment, with its image processing toolbox. To test the system, a database of 756 grayscale eye images courtesy of Chinese Academy of Sciences-Institute of Automation (CASIA is used. The system is to be composed of a number of sub-systems, which correspond to each stage of iris recognition. These stages are- image acquisition, segmentation, normalization and feature encoding. The input to the system will be an eye image, and the output will be an iris template, which will provide a mathematical representation of the iris region. Which conclude the objectives to design recognition system are- study of different biometrics and their features? Study of different recognition systems and their steps, selection of simple and efficient recognition algorithm for implementation, selection of fast and efficient tool for processing, apply the implemented algorithm to different database and find out performance factors.

  5. Presence detection under optimum fusion in an ultrasonic sensor system.

    Srinivasan, Sriram; Pandharipande, Ashish


    Reliable presence detection is a requirement in energy-efficient occupancy-adaptive indoor lighting systems. A system of multiple ultrasonic sensors is considered for presence detection, and the performance gain from optimum fusion is studied. Two cases are considered wherein an individual sensor determines presence based on (i) local detection by processing echoes at its receiver, and (ii) the optimum Chair-Varshney fusion rule using multiple sensor detection results. The performance gains of using optimum fusion over local detection are characterized under different sensor system configurations and it is shown that improved detection sensitivity is obtained over a larger detection coverage region.

  6. Introduction to detection systems

    Larsen, Jan

    Presentation of the information processing pipleline for detection including discussing of various issues and the use of mathematical modeling. A simple example of detection a signal in noise illustrated that simple modeling outperforms human visual and auditory perception. Particiants are going...... to discuss issues in detection which is followed by an auditory object recognition exercise. The results of the exercise and its relation to issues in the information processing pipleline is also discussed....

  7. Statistical fault detection in photovoltaic systems

    Garoudja, Elyes


    Faults in photovoltaic (PV) systems, which can result in energy loss, system shutdown or even serious safety breaches, are often difficult to avoid. Fault detection in such systems is imperative to improve their reliability, productivity, safety and efficiency. Here, an innovative model-based fault-detection approach for early detection of shading of PV modules and faults on the direct current (DC) side of PV systems is proposed. This approach combines the flexibility, and simplicity of a one-diode model with the extended capacity of an exponentially weighted moving average (EWMA) control chart to detect incipient changes in a PV system. The one-diode model, which is easily calibrated due to its limited calibration parameters, is used to predict the healthy PV array\\'s maximum power coordinates of current, voltage and power using measured temperatures and irradiances. Residuals, which capture the difference between the measurements and the predictions of the one-diode model, are generated and used as fault indicators. Then, the EWMA monitoring chart is applied on the uncorrelated residuals obtained from the one-diode model to detect and identify the type of fault. Actual data from the grid-connected PV system installed at the Renewable Energy Development Center, Algeria, are used to assess the performance of the proposed approach. Results show that the proposed approach successfully monitors the DC side of PV systems and detects temporary shading.

  8. Reliability Analysis of Partially Repairable Systems%部分可修系统的可靠性分析



    The reliability analysis of a system with repairable failures and non-repairable failures is presented. It is assumed that the system has n repairable failure modes and m non-repairable failure modes. As one repairable failure mode takes place, the system will be repaired after the failure mode is detected, otherwise, it would never work again when attaining one non-repairable failure mode. Thus, the system brings about new reliability indices for having both repairable failures and non-repairable failures. The definitions of the new reliability indices are given, and the calculating methods for them are derived by using probability analysis and the supplementary variable technique.

  9. Modeling service time reliability in urban ferry system

    Chen, Yifan; Luo, Sida; Zhang, Mengke; Shen, Hanxia; Xin, Feifei; Luo, Yujie


    The urban ferry system can carry a large number of travelers, which may alleviate the pressure on road traffic. As an indicator of its service quality, service time reliability (STR) plays an essential part in attracting travelers to the ferry system. A wide array of studies have been conducted to analyze the STR of land transportation. However, the STR of ferry systems has received little attention in the transportation literature. In this study, a model was established to obtain the STR in urban ferry systems. First, the probability density function (PDF) of the service time provided by ferry systems was constructed. Considering the deficiency of the queuing theory, this PDF was determined by Bayes’ theorem. Then, to validate the function, the results of the proposed model were compared with those of the Monte Carlo simulation. With the PDF, the reliability could be determined mathematically by integration. Results showed how the factors including the frequency, capacity, time schedule and ferry waiting time affected the STR under different degrees of congestion in ferry systems. Based on these results, some strategies for improving the STR were proposed. These findings are of great significance to increasing the share of ferries among various urban transport modes.

  10. Digital array gas radiometer (DAGR): a sensitive and reliable trace gas detection concept

    Gordley, Larry L.; McHugh, Martin J.; Marshall, B. T.; Thompson, Earl


    The Digital Array Gas Radiometer (DAGR) concept is based on traditional and reliable Gas Filter Correlation Radiometry (GFCR) for remote trace gas detection and monitoring. GFCR sensors have been successful in many infrared remote sensing applications. Historically however, solar backscatter measurements have not been as successful because instrument designs have been susceptible to natural variations in surface albedo, which induce clutter and degrade the sensitivity. DAGR overcomes this limitation with several key innovations. First, a pupil imaging system scrambles the received light, removing nearly all spatial clutter and permitting a small calibration source to be easily inserted. Then, by using focal plane arrays rather than single detectors to collect the light, dramatic advances in dynamic range can be achieved. Finally, when used with the calibration source, data processing approaches can further mitigate detector non-uniformity effects. DAGR sensors can be made as small as digital cameras and are well suited for downlooking detection of gases in the boundary layer, where solar backscatter measurements are needed to overcome the lack of thermal contrast in the IR. Easily integrated into a satellite platform, a space-based DAGR would provide near-global sensing of climatically important species such as such as CO, CH4, and N2O. Aircraft and UAV measurements with a DAGR could be used to monitor agricultural and industrial emissions. Ground-based or portable DAGRs could augment early warning systems for chemical weapons or toxic materials. Finally, planetary science applications include detection and mapping of biomarkers such as CH4 in the Martian atmosphere.

  11. Reliability in automotive and mechanical engineering determination of component and system reliability

    Bertsche, Bernd


    In the present contemporary climate of global competition in every branch of engineering and manufacture it has been shown from extensive customer surveys that above every other attribute, reliability stands as the most desired feature in a finished product. To survive this relentless fight for survival any organisation, which neglect the plea of attaining to excellence in reliability, will do so at a serious cost Reliability in Automotive and Mechanical Engineering draws together a wide spectrum of diverse and relevant applications and analyses on reliability engineering. This is distilled into this attractive and well documented volume and practising engineers are challenged with the formidable task of simultaneously improving reliability and reducing the costs and down-time due to maintenance. The volume brings together eleven chapters to highlight the importance of the interrelated reliability and maintenance disciplines. They represent the development trends and progress resulting in making this book ess...

  12. LAMP using a disposable pocket warmer for anthrax detection, a highly mobile and reliable method for anti-bioterrorism.

    Hatano, Ben; Maki, Takayuki; Obara, Takeyuki; Fukumoto, Hitomi; Hagisawa, Kohsuke; Matsushita, Yoshitaro; Okutani, Akiko; Bazartseren, Boldbaastar; Inoue, Satoshi; Sata, Tetsutaro; Katano, Harutaka


    A quick, reliable detection system is necessary to deal with bioterrorism. Loop-mediated isothermal amplification (LAMP) is a DNA amplification method that can amplify specific DNA fragments in isothermal conditions. We developed a new highly mobile and practical LAMP anthrax detection system that uses a disposable pocket warmer without the need for electricity (pocket-warmer LAMP). In our tests, the detection limit of the pocket-warmer LAMP was 1,000 copies of Bacillus anthracis pag and capB gene fragments per tube. The pocket-warmer LAMP also detected B. anthracis genes from DNA extracted from 0.1 volume of a B. anthracis colony. The lower detection limit of the pocket-warmer LAMP was not significantly different from that of a conventional LAMP using a heat block, and was not changed under cold (4 degrees C) or warm (37 degrees C) conditions in a Styrofoam box. The pocket-warmer LAMP could be useful against bioterrorism, and as a sensitive, reliable detection tool in areas with undependable electricity infrastructures.

  13. Design for Reliability of Power Electronics in Renewable Energy Systems

    Ma, Ke; Yang, Yongheng; Wang, Huai


    Power electronics is the enabling technology for maximizing the power captured from renewable electrical generation, e.g., the wind and solar technology, and also for an efficient integration into the grid. Therefore, it is important that the power electronics are reliable and do not have too many...... failures during operation which otherwise will increase cost for operation, maintenance and reputation. Typically, power electronics in renewable electrical generation has to be designed for 20–30 years of operation, and in order to do that, it is crucial to know about the mission profile of the power...... electronics technology as well as to know how the power electronics technology is loaded in terms of temperature and other stressors relevant, to reliability. Hence, this chapter will show the basics of power electronics technology for renewable energy systems, describe the mission profile of the technology...

  14. Reliability-Based Control Design for Uncertain Systems

    Crespo, Luis G.; Kenny, Sean P.


    This paper presents a robust control design methodology for systems with probabilistic parametric uncertainty. Control design is carried out by solving a reliability-based multi-objective optimization problem where the probability of violating design requirements is minimized. Simultaneously, failure domains are optimally enlarged to enable global improvements in the closed-loop performance. To enable an efficient numerical implementation, a hybrid approach for estimating reliability metrics is developed. This approach, which integrates deterministic sampling and asymptotic approximations, greatly reduces the numerical burden associated with complex probabilistic computations without compromising the accuracy of the results. Examples using output-feedback and full-state feedback with state estimation are used to demonstrate the ideas proposed.

  15. Reliability and minimal detectable difference in multisegment foot kinematics during shod walking and running.

    Milner, Clare E; Brindle, Richard A


    There has been increased interest recently in measuring kinematics within the foot during gait. While several multisegment foot models have appeared in the literature, the Oxford foot model has been used frequently for both walking and running. Several studies have reported the reliability for the Oxford foot model, but most studies to date have reported reliability for barefoot walking. The purpose of this study was to determine between-day (intra-rater) and within-session (inter-trial) reliability of the modified Oxford foot model during shod walking and running and calculate minimum detectable difference for common variables of interest. Healthy adult male runners participated. Participants ran and walked in the gait laboratory for five trials of each. Three-dimensional gait analysis was conducted and foot and ankle joint angle time series data were calculated. Participants returned for a second gait analysis at least 5 days later. Intraclass correlation coefficients and minimum detectable difference were determined for walking and for running, to indicate both within-session and between-day reliability. Overall, relative variables were more reliable than absolute variables, and within-session reliability was greater than between-day reliability. Between-day intraclass correlation coefficients were comparable to those reported previously for adults walking barefoot. It is an extension in the use of the Oxford foot model to incorporate wearing a shoe while maintaining marker placement directly on the skin for each segment. These reliability data for walking and running will aid in the determination of meaningful differences in studies which use this model during shod gait.

  16. Reliability of System Identification Techniques to Assess Standing Balance in Healthy Elderly.

    Jantsje H Pasma

    Full Text Available System identification techniques have the potential to assess the contribution of the underlying systems involved in standing balance by applying well-known disturbances. We investigated the reliability of standing balance parameters obtained with multivariate closed loop system identification techniques.In twelve healthy elderly balance tests were performed twice a day during three days. Body sway was measured during two minutes of standing with eyes closed and the Balance test Room (BalRoom was used to apply four disturbances simultaneously: two sensory disturbances, to the proprioceptive and the visual system, and two mechanical disturbances applied at the leg and trunk segment. Using system identification techniques, sensitivity functions of the sensory disturbances and the neuromuscular controller were estimated. Based on the generalizability theory (G theory, systematic errors and sources of variability were assessed using linear mixed models and reliability was assessed by computing indexes of dependability (ID, standard error of measurement (SEM and minimal detectable change (MDC.A systematic error was found between the first and second trial in the sensitivity functions. No systematic error was found in the neuromuscular controller and body sway. The reliability of 15 of 25 parameters and body sway were moderate to excellent when the results of two trials on three days were averaged. To reach an excellent reliability on one day in 7 out of 25 parameters, it was predicted that at least seven trials must be averaged.This study shows that system identification techniques are a promising method to assess the underlying systems involved in standing balance in elderly. However, most of the parameters do not appear to be reliable unless a large number of trials are collected across multiple days. To reach an excellent reliability in one third of the parameters, a training session for participants is needed and at least seven trials of two

  17. Reliability of System Identification Techniques to Assess Standing Balance in Healthy Elderly.

    Pasma, Jantsje H; Engelhart, Denise; Maier, Andrea B; Aarts, Ronald G K M; van Gerven, Joop M A; Arendzen, J Hans; Schouten, Alfred C; Meskers, Carel G M; van der Kooij, Herman


    System identification techniques have the potential to assess the contribution of the underlying systems involved in standing balance by applying well-known disturbances. We investigated the reliability of standing balance parameters obtained with multivariate closed loop system identification techniques. In twelve healthy elderly balance tests were performed twice a day during three days. Body sway was measured during two minutes of standing with eyes closed and the Balance test Room (BalRoom) was used to apply four disturbances simultaneously: two sensory disturbances, to the proprioceptive and the visual system, and two mechanical disturbances applied at the leg and trunk segment. Using system identification techniques, sensitivity functions of the sensory disturbances and the neuromuscular controller were estimated. Based on the generalizability theory (G theory), systematic errors and sources of variability were assessed using linear mixed models and reliability was assessed by computing indexes of dependability (ID), standard error of measurement (SEM) and minimal detectable change (MDC). A systematic error was found between the first and second trial in the sensitivity functions. No systematic error was found in the neuromuscular controller and body sway. The reliability of 15 of 25 parameters and body sway were moderate to excellent when the results of two trials on three days were averaged. To reach an excellent reliability on one day in 7 out of 25 parameters, it was predicted that at least seven trials must be averaged. This study shows that system identification techniques are a promising method to assess the underlying systems involved in standing balance in elderly. However, most of the parameters do not appear to be reliable unless a large number of trials are collected across multiple days. To reach an excellent reliability in one third of the parameters, a training session for participants is needed and at least seven trials of two minutes must be

  18. Scenario based approach to structural damage detection and its value in a risk and reliability perspective

    Hovgaard, Mads Knude; Hansen, Jannick Balleby; Brincker, Rune


    A scenario- and vibration based structural damage detection method is demonstrated though simulation. The method is Finite Element (FE) based. The value of the monitoring is calculated using structural reliability theory. A high cycle fatigue crack propagation model is assumed as the damage mecha...

  19. Reliability of magnetic susceptibility weighted imaging in detection of cerebral microbleeds in stroke patients

    Lamiaa G. El-Serougy


    Conclusion: SWI is an important reliable technique allows accurate detection of CMBs occurring in association with hemorrhage in acute and chronic stroke and should be included in the protocols for assessment of stroke to help in choice of proper treatment and prediction of future attacks.

  20. Reliability and minimal detectable change of the weight-bearing lunge test: A systematic review.

    Powden, Cameron J; Hoch, Johanna M; Hoch, Matthew C


    Ankle dorsiflexion range of motion (DROM) is often a point of emphasis during the rehabilitation of lower extremity pathologies. With the growing popularity of weight-bearing DROM assessments, several versions of the weight-bearing lunge (WBLT) test have been developed and numerous reliability studies have been conducted. The purpose of this systematic review was to critically appraise and synthesize the studies which examined the reliability and responsiveness of the WBLT to assess DROM. A systematic search of PubMed and EBSCO Host databases from inception to September 2014 was conducted to identify studies whose primary aim was assessing the reliability of the WBLT. The Quality Appraisal of Reliability Studies assessment tool was utilized to determine the quality of included studies. Relative reliability was examined through intraclass correlation coefficients (ICC) and responsiveness was evaluated through minimal detectable change (MDC). A total of 12 studies met the eligibility criteria and were included. Nine included studies assessed inter-clinician reliability and 12 included studies assessed intra-clinician reliability. There was strong evidence that inter-clinician reliability (ICC = 0.80-0.99) as well as intra-clinician reliability (ICC = 0.65-0.99) of the WBLT is good. Additionally, average MDC scores of 4.6° or 1.6 cm for inter-clinician and 4.7° or 1.9 cm for intra-clinician were found, indicating the minimal change in DROM needed to be outside the error of the WBLT. This systematic review determined that the WBLT, regardless of method, can be used clinically to assess DROM as it provides consistent results between one or more clinicians and demonstrates reasonable responsiveness. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. System reliability in design and maintenance of fixed offshore structures

    Dalane, J.I.


    Offshore structures are usually redundant, and several components must fail before structural collapse occurs. This work deals with system reliability for fatigue and overload of typical steel truss and frame structure such as jackets and jack-ups. The application of system reliability in design and maintenance is addressed. A formulation for a failure sequence of fatigue and overload is presented. The basic failure event for fatigue, is defined in terms of time to section failure. For overload, realistic failure criteria are applied. After an overload failure, the member replacement technique is used to account for the post collapse behavior. The branch and bound algorithm is used to identify important failure sequences, and system failure occur if any of these collapse sequences occur. The first order reliability methods are efficiently used to calculate the failure probabilities. In this work the importance of uncertainties in load and ultimate strength for a jacket and a jack-up structure is discussed. A joint environmental model for wave and current loading is applied. Ultimate capacity is calculated by nonlinear pushover analysis, and the uncertainties identified by Monte Carlo simulation. Fatigue may be an important failure mode for offshore structure, and in-service inspections are frequently performed. Underwater inspections are, however, very expensive and it is therefore important that the inspections are performed in such a way that they significantly increase our knowledge about the safety of the structure. In this work an inspection importance factor is defined. This importance factor can be used to identify the most important members in the system from an inspection point of view. Inspection for unexpected damages are also discussed. 122 refs., 72 figs., 50 tabs.

  2. Reliability of automotive and mechanical engineering. Determination of component and system reliability

    Bertsche, Bernd [Stuttgart Univ. (Germany). Inst. fuer Maschinenelemente


    In the present contemporary climate of global competition in every branch of engineering and manufacture it has been shown from extensive customer surveys that above every other attribute, reliability stands as the most desired feature in a finished product. To survive this relentless fight for survival any organisation, which neglect the plea of attaining to excellence in reliability, will do so at a serious cost Reliability in Automotive and Mechanical Engineering draws together a wide spectrum of diverse and relevant applications and analyses on reliability engineering. This is distilled into this attractive and well documented volume and practising engineers are challenged with the formidable task of simultaneously improving reliability and reducing the costs and down-time due to maintenance. The volume brings together eleven chapters to highlight the importance of the interrelated reliability and maintenance disciplines. They represent the development trends and progress resulting in making this book essential basic material for all research academics, planners maintenance executives, who have the responsibility to implement the findings and maintenance audits into a cohesive reliability policy. Although, the book is centred on automotive engineering nevertheless, the examples and overall treatise can be applied to a wide range of professional practices. The book will be a valuable source of information for those concerned with improved manufacturing performance and the formidable task of optimising reliability. (orig.)

  3. Structural Reliability Methods for Wind Power Converter System Component Reliability Assessment

    Kostandyan, Erik; Sørensen, John Dalsgaard


    is defined by the threshold model. The attention is focused on crack propagation in solder joints of electrical components due to the temperature loadings. Structural Reliability approaches are used to incorporate model, physical and statistical uncertainties. Reliability estimation by means of structural...

  4. A Reliable Adaptive High-Definition Transmission System for Distance Learning


    There is an increasing demand for supporting high-quality real-time audiovisual services for the next generation wired and wireless networks. However, due to variety of bandwidths of different networks, it is a great challenge for deployment. In this paper, a novel high-definition (HD) video transmission system was proposed which depends upon reliable compound multicast protocols and QoS control over the various kinds of networks.This system detects client's network condition and assigns it to a proper proxy. Each proxy is capable of detecting network parameters and adaptively tuning such transport parameters as bit rate, video resolution, frame rate and QoS mechanisms to this condition. It also provides FEC error recovery under consideration of characteristics of MPEG4 video codec. Our simulation demonstrates that different network clients such as ADSL, CERNET, and CERNET2 can receive more video reliability with less delay.

  5. The Reliability of Wireless Sensor Network on Pipeline Monitoring System

    Hafizh Prihtiadi


    Full Text Available The wireless sensor network (WSN is an attractive technology, which combines embedded systems and communication networks making them more efficient and effective. Currently, WSNs have been developed for various monitoring applications. In this research, a wireless mesh network for a pipeline monitoring system was designed and developed. Sensor nodes were placed at each branch in the pipe system. Some router fails were simulated and the response of each node in the network was evaluated. Three different scenarios were examined to test the data transmission performance. The results proved that the wireless mesh network was reliable and robust. The system is able to perform link reconfiguration, automatic routing and safe data transmission from the beginning node to the end node.

  6. A Model of Ship Auxiliary System for Reliable Ship Propulsion

    Dragan Martinović


    Full Text Available The main purpose of a vessel is to transport goods and passengers at minimum cost. Out of the analysis of relevant global databases on ship machinery failures, it is obvious that the most frequent failures occur precisely on the generator-running diesel engines. Any failure in the electrical system can leave the ship without propulsion, even if the main engine is working properly. In that case, the consequences could be devastating: higher running expenses, damage to the ship, oil spill or substantial marine pollution. These are the reasons why solutions that will prevent the ship being unable to manoeuvre during her exploitation should be implemented. Therefore, it is necessary to define a propulsion restoration model which would not depend on the primary electrical energy. The paper provides a model of the marine auxiliary system for more reliable propulsion. This includes starting, reversing and stopping of the propulsion engine. The proposed solution of reliable propulsion model based on the use of a shaft generator and an excitation engine enables the restoration of propulsion following total failure of the electrical energy primary production system, and the self-propelled ship navigation. A ship is an important factor in the Technology of Transport, and the implementation of this model increases safety, reduces downtime, and significantly decreases hazards of pollution damage.KEYWORDSreliable propulsion, failure, ship auxiliary system, control, propulsion restoration

  7. Reliability of recordings of subgingival calculus detected using an ultrasonic device.

    Corraini, Priscila; López, Rodrigo


    To assess the intra-examiner reliability of recordings of subgingival calculus detected using an ultrasonic device, and to investigate the influence of subject-, tooth- and site-level factors on the reliability of these subgingival calculus recordings. On two occasions, within a 1-week interval, 147 adult periodontitis patients received a full-mouth clinical periodontal examination by a single trained examiner. Duplicate subgingival calculus recordings, in six sites per tooth, were obtained using an ultrasonic device for calculus detection and removal. Agreement was observed in 65 % of the 22,584 duplicate subgingival calculus recordings, ranging 45 % to 83 % according to subject. Using hierarchical modeling, disagreements in the subgingival calculus duplicate recordings were more likely in all other sites than the mid-buccal, and in sites harboring supragingival calculus. Disagreements were less likely in sites with PD ≥  4 mm and with furcation involvement  ≥  degree 2. Bleeding on probing or suppuration did not influence the reliability of subgingival calculus. At the subject-level, disagreements were less likely in patients presenting with the highest and lowest extent categories of the covariate subgingival calculus. The reliability of subgingival calculus recordings using the ultrasound technology is reasonable. The results of the present study suggest that the reliability of subgingival calculus recordings is not influenced by the presence of inflammation. Moreover, subgingival calculus can be more reliably detected using the ultrasound device at sites with higher need for periodontal therapy, i.e., sites presenting with deep pockets and premolars and molars with furcation involvement.

  8. Bitwise identical compiling setup: prospective for reproducibility and reliability of earth system modeling

    R. Li


    Full Text Available Reproducibility and reliability are fundamental principles of scientific research. A compiling setup that includes a specific compiler version and compiler flags is essential technical supports for Earth system modeling. With the fast development of computer software and hardware, compiling setup has to be updated frequently, which challenges the reproducibility and reliability of Earth system modeling. The existing results of a simulation using an original compiling setup may be irreproducible by a newer compiling setup because trivial round-off errors introduced by the change of compiling setup can potentially trigger significant changes in simulation results. Regarding the reliability, a compiler with millions of lines of codes may have bugs that are easily overlooked due to the uncertainties or unknowns in Earth system modeling. To address these challenges, this study shows that different compiling setups can achieve exactly the same (bitwise identical results in Earth system modeling, and a set of bitwise identical compiling setups of a model can be used across different compiler versions and different compiler flags. As a result, the original results can be more easily reproduced; for example, the original results with an older compiler version can be reproduced exactly with a newer compiler version. Moreover, this study shows that new test cases can be generated based on the differences of bitwise identical compiling setups between different models, which can help detect software bugs or risks in the codes of models and compilers and finally improve the reliability of Earth system modeling.

  9. Reliability-Based Inspection Planning for Structural Systems

    Sørensen, John Dalsgaard


    A general model for reliability-based optimal inspection and repair strategies for structural systems is described. The total expected costs in the design lifetime is minimized with the number of inspections, the inspection times and efforts as decision variables. The equivalence of this model...... with a preposterior analysis from statistical decision theory is discussed. It is described how information obtained by an inspection can be used in a repair decision. Stochastic models for inspection, measurement and repair actions are presented. The general model is applied for inspection and repair planning...

  10. Methods for reliability evaluation of trust and reputation systems

    Janiszewski, Marek B.


    Trust and reputation systems are a systematic approach to build security on the basis of observations of node's behaviour. Exchange of node's opinions about other nodes is very useful to indicate nodes which act selfishly or maliciously. The idea behind trust and reputation systems gets significance because of the fact that conventional security measures (based on cryptography) are often not sufficient. Trust and reputation systems can be used in various types of networks such as WSN, MANET, P2P and also in e-commerce applications. Trust and reputation systems give not only benefits but also could be a thread itself. Many attacks aim at trust and reputation systems exist, but such attacks still have not gain enough attention of research teams. Moreover, joint effects of many of known attacks have been determined as a very interesting field of research. Lack of an acknowledged methodology of evaluation of trust and reputation systems is a serious problem. This paper aims at presenting various approaches of evaluation such systems. This work also contains a description of generalization of many trust and reputation systems which can be used to evaluate reliability of such systems in the context of preventing various attacks.

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

    B. Mazzorana


    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.

  12. Reliability analysis of repairable systems using system dynamics modeling and simulation

    Srinivasa Rao, M.; Naikan, V. N. A.


    Repairable standby system's study and analysis is an important topic in reliability. Analytical techniques become very complicated and unrealistic especially for modern complex systems. There have been attempts in the literature to evolve more realistic techniques using simulation approach for reliability analysis of systems. This paper proposes a hybrid approach called as Markov system dynamics (MSD) approach which combines the Markov approach with system dynamics simulation approach for reliability analysis and to study the dynamic behavior of systems. This approach will have the advantages of both Markov as well as system dynamics methodologies. The proposed framework is illustrated for a standby system with repair. The results of the simulation when compared with that obtained by traditional Markov analysis clearly validate the MSD approach as an alternative approach for reliability analysis.


    才庆祥; 彭世济; 张达贤


    Subjected to various stochastic factors, surface mining engineering reliability is difficult to solve by using general reliability mathematical method. The concept of reliability measurement is introduced; And the authors have combined system simulation method with CAD technique and developed an interactive color character graphic design system for evaluating and solving the mining engineering reliability in surface mines under the given constraints.

  14. Reliability and Maintainability Data for Liquid Metal Cooling Systems

    Cadwallader, Lee Charles [Idaho National Laboratory


    One of the coolants of interest for future fusion breeding blankets is lead-lithium. As a liquid metal it offers the advantages of high temperature operation for good station efficiency, low pressure, and moderate flow rate. This coolant is also under examination for use in test blanket modules to be used in the ITER international project. To perform reliability, availability, maintainability and inspectability (RAMI) assessment as well as probabilistic safety assessment (PSA) of lead-lithium cooling systems, component failure rate data are needed to quantify the system models. RAMI assessment also requires repair time data and inspection time data. This paper presents a new survey of the data sets that are available at present to support RAMI and PSA quantification. Recommendations are given for the best data values to use when quantifying system models.

  15. Force protection demining system (FPDS) detection subsystem

    Zachery, Karen N.; Schultz, Gregory M.; Collins, Leslie M.


    This study describes the U.S. Army Force Protection Demining System (FPDS); a remotely-operated, multisensor platform developed for reliable detection and neutralization of both anti-tank and anti-personnel landmines. The ongoing development of the prototype multisensor detection subsystem is presented, which integrates an advanced electromagnetic pulsed-induction array and ground penetrating synthetic aperture radar array on a single standoff platform. The FPDS detection subsystem is mounted on a robotic rubber-tracked vehicle and incorporates an accurate and precise navigation/positioning module making it well suited for operation in varied and irregular terrains. Detection sensors are optimally configured to minimize interference without loss in sensitivity or performance. Mine lane test data acquired from the prototype sensors are processed to extract signal- and image-based features for automatic target recognition. Preliminary results using optimal feature and classifier selection indicate the potential of the system to achieve high probabilities of detection while minimizing false alarms. The FPDS detection software system also exploits modern multi-sensor data fusion algorithms to provide real-time detection and discrimination information to the user.

  16. Health and safety management system audit reliability pilot project.

    Dyjack, D T; Redinger, C F; Ridge, R S


    This pilot study assessed occupational health and safety (OHS) management system audit finding reliability using a modified test-retest method. Two industrial hygienists with similar training and education conducted four, 1-day management system audits in four dissimilar organizational environments. The researchers examined four auditable sections (employee participation, training, controls, and communications) contained in a publicly available OHS management system assessment instrument. At each site, 102 auditable clauses were evaluated using a progressive 6-point scale. The team examined both the consistency of and agreement between the scores of the two auditors. Consistency was evaluated by calculating the Pearson r correlations for the two auditors' scores at each site and for each section within each site. Pearson correlations comparing overall scores for each site were all very low, ranging from 0.206 to 0.543. Training and communication system assessments correlated the highest, whereas employee participation and control system scores correlated the least. To measure agreement, t-tests were first calculated to determine whether the differences were statistically significant. Aggregate mean scores for two of the four sites were significantly different. Of the 16 total sections evaluated (i.e., 4 sections per site), seven scores were significantly different. Finally, the agreement of the scores between the two auditors for the four sites was evaluated by calculating two types of intraclass correlation coefficients, all of which failed to meet the minimum requirement for agreement. These findings suggest that opportunities for improving the reliability of the instrument and the audit process exist. Future research should include governmental and commercial OHS program assessments and related environmental management systems and their attendant audit protocols.

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

    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)


    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.

  18. Reliability Evaluation of Distributed Computer Systems Subject to Imperfect Coverage and Dependent Common-Cause Failures

    Liudong Xing


    Full Text Available Imperfect coverage (IPC occurs when a malicious component failure causes extensive damage due to inadequate fault detection, fault location or fault recovery. Common-cause failures (CCF are multiple dependent component failures within a system due to a shared root cause. Both imperfect coverage and common-cause failures can exist in distributed computer systems and can contribute significantly to the overall system unreliability. Moreover they can complicate the reliability analysis. In this study, we propose an efficient approach to the reliability analysis of distributed computer systems (DCS with both IPC and CCF. The proposed methodology is to decouple the effects of IPC and CCF from the combinatorics of the solution. The resulting approach is applicable to the computationally efficient binary decision diagrams (BDD based method for the reliability analysis of DCS. We provide a concrete analysis of an example DCS to illustrate the application and advantages of our approach. Due to the consideration of IPC and CCF, our approach can evaluate a wider class of DCS as compared with existing approaches. Due to the nature of the BDD and the separation of IPC and CCF from the solution combinatorics, our approach has high computational efficiency and is easy to implement, which means that it can be easily applied to the accurate reliability analysis of large-scale DCS subject to IPC and CCF. The DCS without IPC or CCF appear to be special cases of our approach.

  19. Study of turboprop systems reliability and maintenance costs


    The overall reliability and maintenance costs (R&MC's) of past and current turboprop systems were examined. Maintenance cost drivers were found to be scheduled overhaul (40%), lack of modularity particularly in the propeller and reduction gearbox, and lack of inherent durability (reliability) of some parts. Comparisons were made between the 501-D13/54H60 turboprop system and the widely used JT8D turbofan. It was found that the total maintenance cost per flight hour of the turboprop was 75% higher than that of the JT8D turbofan. Part of this difference was due to propeller and gearbox costs being higher than those of the fan and reverser, but most of the difference was in the engine core where the older technology turboprop core maintenance costs were nearly 70 percent higher than for the turbofan. The estimated maintenance cost of both the advanced turboprop and advanced turbofan were less than the JT8D. The conclusion was that an advanced turboprop and an advanced turbofan, using similar cores, will have very competitive maintenance costs per flight hour.

  20. Adaptive and Reliable Control Algorithm for Hybrid System Architecture

    Osama Abdel Hakeem Abdel Sattar


    Full Text Available A stand-alone system is defined as an autonomous system that supplies electricity without being connected to the electric grid. Hybrid systems combined renewable energy source, that are never depleted (such solar (photovoltaic (PV, wind, hydroelectric, etc. , With other sources of energy, like Diesel. If these hybrid systems are optimally designed, they can be more cost effective and reliable than single systems. However, the design of hybrid systems is complex because of the uncertain renewable energy supplies, load demands and the non-linear characteristics of some components, so the design problem cannot be solved easily by classical optimisation methods. The use of heuristic techniques, such as the genetic algorithms, can give better results than classical methods. This paper presents to a hybrid system control algorithm and also dispatches strategy design in which wind is the primary energy resource with photovoltaic cells. The dimension of the design (max. load is 2000 kW and the sources is implemented as flow 1500 kw from wind, 500 kw from solar and diesel 2000 kw. The main task of the preposed algorithm is to take full advantage of the wind energy and solar energy when it is available and to minimize diesel fuel consumption.

  1. Detectability and reliability analysis of the local seismic network in Pakistan


    The detectability and reliability analysis for the local seismic network is performed employing by Bungum and Husebye technique. The events were relocated using standard computer codes for hypocentral locations. The detectability levels are estimated from the twenty-five years of recorded data in terms of 50(, 90( and 100( cumulative detectability thresholds, which were derived from frequency-magnitude distribution. From this analysis the 100( level of detectability of the network is ML=1.7 for events which occur within the network. The accuracy in hypocentral solutions of the network is investigated by considering the fixed real hypocenter within the network. The epicentral errors are found to be less than 4 km when the events occur within the network. Finally, the problems faced during continuous operation of the local network, which effects its detectability, are discussed.

  2. Reliability Considerations of ULP Scaled CMOS in Spacecraft Systems

    White, Mark; MacNeal, Kristen; Cooper, Mark


    NASA, the aerospace community, and other high reliability (hi-rel) users of advanced microelectronic products face many challenges as technology continues to scale into the deep sub-micron region. Decreasing the feature size of CMOS devices not only allows more components to be placed on a single chip, but it increases performance by allowing faster switching (or clock) speeds with reduced power compared to larger scaled devices. Higher performance, and lower operating and stand-by power characteristics of Ultra-Low Power (ULP) microelectronics are not only desirable, but also necessary to meet low power consumption design goals of critical spacecraft systems. The integration of these components in such systems, however, must be balanced with the overall risk tolerance of the project.

  3. Space Shuttle Program Primary Avionics Software System (PASS) Success Legacy - Quality and Reliability Date

    Orr, James K.; Peltier, Daryl


    Thsi slide presentation reviews the avionics software system on board the space shuttle, with particular emphasis on the quality and reliability. The Primary Avionics Software System (PASS) provides automatic and fly-by-wire control of critical shuttle systems which executes in redundant computers. Charts given show the number of space shuttle flights vs time, PASS's development history, and other charts that point to the reliability of the system's development. The reliability of the system is also compared to predicted reliability.

  4. Digital System Reliability Test for the Evaluation of safety Critical Software of Digital Reactor Protection System

    Hyun-Kook Shin


    Full Text Available A new Digital Reactor Protection System (DRPS based on VME bus Single Board Computer has been developed by KOPEC to prevent software Common Mode Failure(CMF inside digital system. The new DRPS has been proved to be an effective digital safety system to prevent CMF by Defense-in-Depth and Diversity (DID&D analysis. However, for practical use in Nuclear Power Plants, the performance test and the reliability test are essential for the digital system qualification. In this study, a single channel of DRPS prototype has been manufactured for the evaluation of DRPS capabilities. The integrated functional tests are performed and the system reliability is analyzed and tested. The results of reliability test show that the application software of DRPS has a very high reliability compared with the analog reactor protection systems.

  5. A particle swarm model for estimating reliability and scheduling system maintenance

    Puzis, Rami; Shirtz, Dov; Elovici, Yuval


    Modifying data and information system components may introduce new errors and deteriorate the reliability of the system. Reliability can be efficiently regained with reliability centred maintenance, which requires reliability estimation for maintenance scheduling. A variant of the particle swarm model is used to estimate reliability of systems implemented according to the model view controller paradigm. Simulations based on data collected from an online system of a large financial institute are used to compare three component-level maintenance policies. Results show that appropriately scheduled component-level maintenance greatly reduces the cost of upholding an acceptable level of reliability by reducing the need in system-wide maintenance.

  6. Reliability-based design optimization of multiphysics, aerospace systems

    Allen, Matthew R.

    Aerospace systems are inherently plagued by uncertainties in their design, fabrication, and operation. Safety factors and expensive testing at the prototype level traditionally account for these uncertainties. Reliability-based design optimization (RBDO) can drastically decrease life-cycle development costs by accounting for the stochastic nature of the system response in the design process. The reduction in cost is amplified for conceptually new designs, for which no accepted safety factors currently exist. Aerospace systems often operate in environments dominated by multiphysics phenomena, such as the fluid-structure interaction of aeroelastic wings or the electrostatic-mechanical interaction of sensors and actuators. The analysis of such phenomena is generally complex and computationally expensive, and therefore is usually simplified or approximated in the design process. However, this leads to significant epistemic uncertainties in modeling, which may dominate the uncertainties for which the reliability analysis was intended. Therefore, the goal of this thesis is to present a RBDO framework that utilizes high-fidelity simulation techniques to minimize the modeling error for multiphysics phenomena. A key component of the framework is an extended reduced order modeling (EROM) technique that can analyze various states in the design or uncertainty parameter space at a reduced computational cost, while retaining characteristics of high-fidelity methods. The computational framework is verified and applied to the RBDO of aeroelastic systems and electrostatically driven sensors and actuators, utilizing steady-state analysis and design criteria. The framework is also applied to the design of electrostatic devices with transient criteria, which requires the use of the EROM technique to overcome the computational burden of multiple transient analyses.

  7. Reliability and minimum detectable change of the gait profile score for post-stroke patients.

    Devetak, Gisele Francini; Martello, Suzane Ketlyn; de Almeida, Juliana Carla; Correa, Katren Pedroso; Iucksch, Dielise Debona; Manffra, Elisangela Ferretti


    The objectives of this work were (i) to determine Gait Profile Score (GPS) for hemiparetic stroke patients, (ii) to evaluate its reliability within and between sessions, and (iii) to establish its minimal detectable change (MDC). Seventeen hemiparetic patients (mean age 54.9±10.5years; 9 men and 8 women; 6 hemiparetic on the left side and 11 on the right side; mean time after stroke 6.1±3.5months) participated in 2 gait assessment sessions within an interval of 2-7 days. Intra-session reliability was obtained from the intraclass correlation coefficient (ICC) between the three strides of each session. Inter-session reliability was estimated by the ICC from the averages of that three strides. GPS value of non paretic lower limb (NPLL) (13.9±2.4°) was greater than that of paretic lower limb (PLL) (12.0±2.8°) and overall GPS (GPS_O) was 13.7±2.5°. The Gait Variable Scores (GVS), GPS and GPS_O exhibited intra-session ICC values between 0.70 and 0.99, suggesting high intra-day stability. Most of GVS exhibited excellent inter-session reliability (ICC between 0.81 and 0.93). Only hip rotation, hip abduction of PLL exhibited moderate reliability with ICC/MDC values of 0.57/10.0° and 0.71/3.1°, respectively. ICC/MDC values of GPS were 0.92/2.3° and 0.93/1.9° for PLL and NPLL, respectively. GPS_O exhibited excellent test-retest reliability (ICC=0.95) and MDC of 1.7°. Given its reliability, the GPS has proven to be a suitable tool for therapeutic assessment of hemiparetic patients after stroke.

  8. An immunological basis for high-reliability systems control.

    Somayaji, Anil B. (Carleton University, Ottawa, ON, Canada); Amai, Wendy A.; Walther, Eleanor A.


    This reports describes the successful extension of artificial immune systems from the domain of computer security to the domain of real time control systems for robotic vehicles. A biologically-inspired computer immune system was added to the control system of two different mobile robots. As an additional layer in a multi-layered approach, the immune system is complementary to traditional error detection and error handling techniques. This can be thought of as biologically-inspired defense in depth. We demonstrated an immune system can be added with very little application developer effort, resulting in little to no performance impact. The methods described here are extensible to any system that processes a sequence of data through a software interface.

  9. Aircraft systems design methodology and dispatch reliability prediction

    Bineid, Mansour


    Aircraft despatch reliability was the main subject of this research in the wider content of aircraft reliability. The factors effecting dispatch reliability, aircraft delay, causes of aircraft delays, and aircraft delay costs and magnitudes were examined. Delay cost elements and aircraft delay scenarios were also studied. It concluded that aircraft dispatch reliability is affected by technical and non-technical factors, and that the former are under the designer's control. It showed that ...

  10. Aircraft systems design methodology and dispatch reliability prediction

    Bineid, Mansour


    Aircraft despatch reliability was the main subject of this research in the wider content of aircraft reliability. The factors effecting dispatch reliability, aircraft delay, causes of aircraft delays, and aircraft delay costs and magnitudes were examined. Delay cost elements and aircraft delay scenarios were also studied. It concluded that aircraft dispatch reliability is affected by technical and non-technical factors, and that the former are under the designer's control. It showed that ...

  11. The Mount Rainier Lahar Detection System

    Lockhart, A. B.; Murray, T. L.


    To mitigate the risk of unheralded lahars from Mount Rainier, the U.S. Geological Survey, in cooperation with Pierce County, Washington, installed a lahar-detection system on the Puyallup and Carbon rivers that originate on Mount Rainier's western slopes. The system, installed in 1998, is designed to automatically detect the passage of lahars large enough to potentially affect populated areas downstream (approximate volume threshold 40 million cubic meters), while ignoring small lahars, earthquakes, extreme weather and floods. Along each river valley upstream, arrays of independent lahar-monitoring stations equipped with geophones and short tripwires telemeter data to a pair of redundant computer base stations located in and near Tacoma at existing public safety facilities that are staffed around the clock. Monitored data consist of ground-vibration levels, tripwire status, and transmissions at regular intervals. The base stations automatically evaluate these data to determine if a dangerous lahar is passing through the station array. The detection algorithm requires significant ground vibration to occur at those stations in the array that are above the anticipated level of inundation, while lower level `deadman' stations, inundated by the flow, experience tripwire breakage or are destroyed. Once a base station detects a lahar, it alerts staff who execute a call-down of public-safety officials and schools, initiating evacuation of areas potentially at risk. Because the system's risk-mitigation task imposes high standards of reliability on all components, it has been under test for several years. To date, the system has operated reliably and without false alarms, including during the nearby M6.8 Nisqually Earthquake on February 28, 2001. The system is being turned over to Pierce County, and activated as part of their lahar warning system.

  12. Contaminant monitoring of hydraulic systems. The need for reliable data

    Day, M.J. [Pall Europe Ltd., Portsmouth (United Kingdom)] Rinkinen, J. [Tampere University of Technology, Tampere (Finland)


    The need for both reliable operation of hydraulic and lubrication systems and long component lives has focused users to the benefits of controlling the contamination in the hydraulic fluid. Maximum operating (target) levels are being implemented as part of a condition based maintenance regime. If these are exceeded, maintenance effort is directed to correcting the rise in consummation level, and so make optimum use of resources as maintenance effort is only affected when it is necessary to do so. Fundamental to ibis aspect of condition based monitoring is the provision of accurate and reliable data in the shortest possible time. This way, corrective actions can be implemented immediately so minimising the damage to components. On-line monitoring devices are a way of achieving this and are seeing increased use, but some are affected by the condition of the fluid. Hence, there is a potential for giving incorrect data which will waste time and effort by initiating unnecessary corrective actions. A more disturbing aspect is the effect on the user of continual errors. The most likely effect would be a loss of confidence in the technique or even complete rejection of it and hence the potential benefits will be lost. This presentation explains how contaminant monitoring techniques are applied to ensure that the potential benefits of operating with clean fluids is realised. It examines the sources of error and shows how the user can interrogate the data and satisfy himself of its authenticity. (orig.) 14 refs.

  13. A Reliable Wireless Control System for Tomato Hydroponics

    Hirofumi Ibayashi


    Full Text Available Agricultural systems using advanced information and communication (ICT technology can produce high-quality crops in a stable environment while decreasing the need for manual labor. The system collects a wide variety of environmental data and provides the precise cultivation control needed to produce high value-added crops; however, there are the problems of packet transmission errors in wireless sensor networks or system failure due to having the equipment in a hot and humid environment. In this paper, we propose a reliable wireless control system for hydroponic tomato cultivation using the 400 MHz wireless band and the IEEE 802.15.6 standard. The 400 MHz band, which is lower than the 2.4 GHz band, has good obstacle diffraction, and zero-data-loss communication is realized using the guaranteed time-slot method supported by the IEEE 802.15.6 standard. In addition, this system has fault tolerance and a self-healing function to recover from faults such as packet transmission failures due to deterioration of the wireless communication quality. In our basic experiments, the 400 MHz band wireless communication was not affected by the plants’ growth, and the packet error rate was less than that of the 2.4 GHz band. In summary, we achieved a real-time hydroponic liquid supply control with no data loss by applying a 400 MHz band WSN to hydroponic tomato cultivation.

  14. A Reliable Wireless Control System for Tomato Hydroponics.

    Ibayashi, Hirofumi; Kaneda, Yukimasa; Imahara, Jungo; Oishi, Naoki; Kuroda, Masahiro; Mineno, Hiroshi


    Agricultural systems using advanced information and communication (ICT) technology can produce high-quality crops in a stable environment while decreasing the need for manual labor. The system collects a wide variety of environmental data and provides the precise cultivation control needed to produce high value-added crops; however, there are the problems of packet transmission errors in wireless sensor networks or system failure due to having the equipment in a hot and humid environment. In this paper, we propose a reliable wireless control system for hydroponic tomato cultivation using the 400 MHz wireless band and the IEEE 802.15.6 standard. The 400 MHz band, which is lower than the 2.4 GHz band, has good obstacle diffraction, and zero-data-loss communication is realized using the guaranteed time-slot method supported by the IEEE 802.15.6 standard. In addition, this system has fault tolerance and a self-healing function to recover from faults such as packet transmission failures due to deterioration of the wireless communication quality. In our basic experiments, the 400 MHz band wireless communication was not affected by the plants' growth, and the packet error rate was less than that of the 2.4 GHz band. In summary, we achieved a real-time hydroponic liquid supply control with no data loss by applying a 400 MHz band WSN to hydroponic tomato cultivation.

  15. Risk Based Reliability Centered Maintenance of DOD Fire Protection Systems


    Reliability Analysis of Underground Fire Water Piping at the Paducah Gaseous Diffusion Plant , January 1990. I I I I U B-8 3 I U I I I I APPENDIX C N...paper No. 7B, 1982. I3IEEE-Std-500-1984. 4INPO 83-034, Nuclear Plant Reliability Data Annual Report, October 1983. 5Nonelectronic Parts Reliability Data


    I.M. Braun


    Full Text Available  This paper presents and analyzes two algorithms for the detection of hail zones in clouds and precipitation: parametric algorithm and adaptive non-parametric algorithm. Reliability of detection of radar signals from hailstones is investigated by statistical simulation with application of experimental researches as initial data. The results demonstrate the limits of both algorithms as well as higher viability of non-parametric algorithm. Polarimetric algorithms are useful for the implementation in ground-based and airborne weather radars.

  17. Remote Voice Detection System


    back to the laser Doppler vibrometer and the digital camera, respectively. Mechanical beam steering mirror modules, such as galvanometer steering...mirror module 43 in accordance with this invention. An appropriate galvanometer -based tracker system has been used for tracking eye motion during laser

  18. Centrifugal unbalance detection system

    Cordaro, Joseph V.; Reeves, George; Mets, Michael


    A system consisting of an accelerometer sensor attached to a centrifuge enclosure for sensing vibrations and outputting a signal in the form of a sine wave with an amplitude and frequency that is passed through a pre-amp to convert it to a voltage signal, a low pass filter for removing extraneous noise, an A/D converter and a processor and algorithm for operating on the signal, whereby the algorithm interprets the amplitude and frequency associated with the signal and once an amplitude threshold has been exceeded the algorithm begins to count cycles during a predetermined time period and if a given number of complete cycles exceeds the frequency threshold during the predetermined time period, the system shuts down the centrifuge.

  19. Reliability of Substation Protection System Based on IEC61850

    XIONG Xiaofu; YU Jun; LIU Xiaofang; SHEN Zhijan


    Although the new technology of protection and automation system of substation based on IEC61850 standard has developed rapidly in China, reliability measures depending on this tech- nology need to be further researched. By taking advantage of convenient information sharing, two kinds of new schemes, shared backup protection unit (SBPU) and signal backup (SB), have been proposed to solve the failure problem of protective devices and current/voltage transducers respec- tively, and the working principle of these two schemes are also described. Furthermore, the key technologies of on-line diagnosis of protective devices' failure and on-line status diagnosis of op- tical or electronic current/voltage transducers to realize the two schemes are proposed.

  20. Tradeoffs for reliable quantum information storage in 2D systems

    Bravyi, Sergey; Terhal, Barbara


    We ask whether there are fundamental limits on storing quantum information reliably in a bounded volume of space. To investigate this question, we study quantum error correcting codes specified by geometrically local commuting constraints on a 2D lattice of finite-dimensional quantum particles. For these 2D systems, we derive a tradeoff between the number of encoded qubits k, the distance of the code d, and the number of particles n. It is shown that kd^2=O(n) where the coefficient in O(n) depends only on the locality of the constraints and dimension of the Hilbert spaces describing individual particles. We show that the analogous tradeoff for the classical information storage is k\\sqrt{d} =O(n).

  1. Budget-Optimal Task Allocation for Reliable Crowdsourcing Systems

    Karger, David R; Shah, Devavrat


    Crowdsourcing systems, in which numerous tasks are electronically distributed to numerous "information piece-workers", have emerged as an effective paradigm for human-powered solving of large scale problems in domains such as image classification, data entry, optical character recognition, recommendation, and proofreading. Because these low-paid workers can be unreliable, nearly all crowdsourcers must devise schemes to increase confidence in their answers, typically by assigning each task multiple times and combining the answers in some way such as majority voting. In this paper, we consider a general model of such crowdsourcing tasks and pose the problem of minimizing the total price (i.e., number of task assignments) that must be paid to achieve a target overall reliability. We give a new algorithm for deciding which tasks to assign to which workers and for inferring correct answers from the workers' answers. We show that our algorithm, inspired by belief propagation and low-rank matrix approximation, signi...

  2. Reliability analysis and design of on-board computer system for small stereo mapping satellite

    马秀娟; 曹喜滨; 马兴瑞


    The on-board computer system for a small satellite is required to be high in reliability, light in weight, small in volume and low in power consumption. This paper describes the on-board computer system with the advantages of both centralized and distributed systems, analyzes its reliability, and briefs the key techniques used to improve its reliability.

  3. 76 FR 64082 - Mandatory Reliability Standards for the Bulk-Power System; Notice of Staff Meeting


    ... Energy Regulatory Commission Mandatory Reliability Standards for the Bulk-Power System; Notice of Staff...\\ Mandatory Reliability Standards for the Bulk-Power System, Order No. 693, FERC Stats. & Regs. ] 31,242... Discussion on the reliability issues relating to ``Single Point of Failure on Protection Systems,'' on...

  4. Fault Detection for Nonlinear Systems

    Stoustrup, Jakob; Niemann, H.H.


    The paper describes a general method for designing fault detection and isolation (FDI) systems for nonlinear processes. For a rich class of nonlinear systems, a nonlinear FDI system can be designed using convex optimization procedures. The proposed method is a natural extension of methods based...

  5. APDS: Autonomous Pathogen Detection System

    Langlois, R G; Brown, S; Burris, L; Colston, B; Jones, L; Makarewicz, T; Mariella, R; Masquelier, D; McBride, M; Milanovich, F; Masarabadi, S; Venkateswaran, K; Marshall, G; Olson, D; Wolcott, D


    An early warning system to counter bioterrorism, the Autonomous Pathogen Detection System (APDS) continuously monitors the environment for the presence of biological pathogens (e.g., anthrax) and once detected, it sounds an alarm much like a smoke detector warns of a fire. Long before September 11, 2001, this system was being developed to protect domestic venues and events including performing arts centers, mass transit systems, major sporting and entertainment events, and other high profile situations in which the public is at risk of becoming a target of bioterrorist attacks. Customizing off-the-shelf components and developing new components, a multidisciplinary team developed APDS, a stand-alone system for rapid, continuous monitoring of multiple airborne biological threat agents in the environment. The completely automated APDS samples the air, prepares fluid samples in-line, and performs two orthogonal tests: immunoassay and nucleic acid detection. When compared to competing technologies, APDS is unprecedented in terms of flexibility and system performance.

  6. Ferromagnetic Objects Magnetovision Detection System

    Michał Nowicki


    Full Text Available This paper presents the application of a weak magnetic fields magnetovision scanning system for detection of dangerous ferromagnetic objects. A measurement system was developed and built to study the magnetic field vector distributions. The measurements of the Earth’s field distortions caused by various ferromagnetic objects were carried out. The ability for passive detection of hidden or buried dangerous objects and the determination of their location was demonstrated.

  7. Running a Reliable Messaging Infrastructure for CERN's Control System

    Ehm, F


    The current middleware for CERN’s Controls System is based on two implementations: CORBA-based Controls MiddleWare (CMW) and Java Messaging Service (JMS). The JMS service is realized using the open source messaging product ActiveMQ and had became an increasing vital part of beam operations as data need to be transported reliably for various areas such as the beam protection system, post mortem analysis, beam commissioning or the alarm system. The current JMS service is made of 18 brokers running either in clusters or as single nodes. The main service is deployed as a two node cluster providing failover and load balancing capabilities for high availability. Non-critical applications running on virtual machines or desktop machines read data via a third broker to decouple the load from the operational main cluster. This scenario has been introduced last year and the statistics showed an uptime of 99.998% and an average data serving rate of 1.6GByte per minute represented by around 150 messages per second. Depl...

  8. System Reliability Assessment of Existing Jacket Platforms in Malaysian Waters

    V.J. Kurian; M.C. Voon; M.M.A. Wahab; M.S. Liew


    Reliability of offshore platforms has become a very important issue in the Malaysian Oil and Gas Industry as, majority of the jacket platforms in Malaysian waters to date, have exceeded their design life. Reliability of a jacket platform can be assessed through reliability index and probability of failure. Conventional metocean consideration uses 100 year return period wave height associated with 100 year return period current velocity and wind speed. However, recent study shows that for Mala...

  9. Statistics and Analysis on Reliability of HVDC Transmission Systems of SGCC



    Reliability level of HVDC power transmission systems becomes an important factor impacting the entire power grid. The author analyzes the reliability of HVDC power transmission systems owned by SGCC since 2003 in respect of forced outage times, forced energy unavailability, scheduled energy unavailability and energy utilization efficiency. The results show that the reliability level of HVDC power transmission systems owned by SGCC is improving. By analyzing different reliability indices of HVDC power transmission system, the maximum asset benefits of power grid can be achieved through building a scientific and reasonable reliability evaluation system.

  10. Development of Probabilistic Reliability Models of Photovoltaic System Topologies for System Adequacy Evaluation

    Ahmad Alferidi


    Full Text Available The contribution of solar power in electric power systems has been increasing rapidly due to its environmentally friendly nature. Photovoltaic (PV systems contain solar cell panels, power electronic converters, high power switching and often transformers. These components collectively play an important role in shaping the reliability of PV systems. Moreover, the power output of PV systems is variable, so it cannot be controlled as easily as conventional generation due to the unpredictable nature of weather conditions. Therefore, solar power has a different influence on generating system reliability compared to conventional power sources. Recently, different PV system designs have been constructed to maximize the output power of PV systems. These different designs are commonly adopted based on the scale of a PV system. Large-scale grid-connected PV systems are generally connected in a centralized or a string structure. Central and string PV schemes are different in terms of connecting the inverter to PV arrays. Micro-inverter systems are recognized as a third PV system topology. It is therefore important to evaluate the reliability contribution of PV systems under these topologies. This work utilizes a probabilistic technique to develop a power output model for a PV generation system. A reliability model is then developed for a PV integrated power system in order to assess the reliability and energy contribution of the solar system to meet overall system demand. The developed model is applied to a small isolated power unit to evaluate system adequacy and capacity level of a PV system considering the three topologies.

  11. Effective confidence interval estimation of fault-detection process of software reliability growth models

    Fang, Chih-Chiang; Yeh, Chun-Wu


    The quantitative evaluation of software reliability growth model is frequently accompanied by its confidence interval of fault detection. It provides helpful information to software developers and testers when undertaking software development and software quality control. However, the explanation of the variance estimation of software fault detection is not transparent in previous studies, and it influences the deduction of confidence interval about the mean value function that the current study addresses. Software engineers in such a case cannot evaluate the potential hazard based on the stochasticity of mean value function, and this might reduce the practicability of the estimation. Hence, stochastic differential equations are utilised for confidence interval estimation of the software fault-detection process. The proposed model is estimated and validated using real data-sets to show its flexibility.

  12. Data driven CAN node reliability assessment for manufacturing system

    Zhang, Leiming; Yuan, Yong; Lei, Yong


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

  13. 48 CFR 1852.246-70 - Mission Critical Space System Personnel Reliability Program.


    ... System Personnel Reliability Program. 1852.246-70 Section 1852.246-70 Federal Acquisition Regulations... Reliability Program. As prescribed in 1846.370(a), insert the following clause: Mission Critical Space System Personnel Reliability Program (MAR 1997) (a) In implementation of the Mission Critical Space...

  14. 75 FR 52528 - Mandatory Reliability Standards for the Bulk-Power System; Notice of Technical Conference


    ... Energy Regulatory Commission Mandatory Reliability Standards for the Bulk-Power System; Notice of... ] 61,053 (2007). \\2\\ Mandatory Reliability Standards for the Bulk Power System, 130 FERC ] 61,218... a frequency response requirement.'' \\3\\ \\1\\ Mandatory Reliability Standards for the...

  15. Fault Detection and Control of Process Systems

    Vu Trieu Minh


    Full Text Available This paper develops a stochastic hybrid model-based control system that can determine online the optimal control actions, detect faults quickly in the control process, and reconfigure the controller accordingly using interacting multiple-model (IMM estimator and generalized predictive control (GPC algorithm. A fault detection and control system consists of two main parts: the first is the fault detector and the second is the controller reconfiguration. This work deals with three main challenging issues: design of fault model set, estimation of stochastic hybrid multiple models, and stochastic model predictive control of hybrid multiple models. For the first issue, we propose a simple scheme for designing faults for discrete and continuous random variables. For the second issue, we consider and select a fast and reliable fault detection system applied to the stochastic hybrid system. Finally, we develop a stochastic GPC algorithm for hybrid multiple-models controller reconfiguration with soft switching signals based on weighted probabilities. Simulations for the proposed system are illustrated and analyzed.

  16. Intrusion Detection System: Security Monitoring System



    Full Text Available An intrusion detection system (IDS is an ad hoc security solution to protect flawed computer systems. It works like a burglar alarm that goes off if someone tampers with or manages to get past other security mechanisms such as authentication mechanisms and firewalls. An Intrusion Detection System (IDS is a device or a software application that monitors network or system activities for malicious activities or policy violations and produces reports to a management station.Intrusion Detection System (IDS has been used as a vital instrument in defending the network from this malicious or abnormal activity..In this paper we are comparing host based and network based IDS and various types of attacks possible on IDS.

  17. Reliability and Minimum Detectable Change of Temporal-Spatial, Kinematic, and Dynamic Stability Measures during Perturbed Gait.

    Christopher A Rábago

    Full Text Available Temporal-spatial, kinematic variability, and dynamic stability measures collected during perturbation-based assessment paradigms are often used to identify dysfunction associated with gait instability. However, it remains unclear which measures are most reliable for detecting and tracking responses to perturbations. This study systematically determined the between-session reliability and minimum detectable change values of temporal-spatial, kinematic variability, and dynamic stability measures during three types of perturbed gait. Twenty young healthy adults completed two identical testing sessions two weeks apart, comprised of an unperturbed and three perturbed (cognitive, physical, and visual walking conditions in a virtual reality environment. Within each session, perturbation responses were compared to unperturbed walking using paired t-tests. Between-session reliability and minimum detectable change values were also calculated for each measure and condition. All temporal-spatial, kinematic variability and dynamic stability measures demonstrated fair to excellent between-session reliability. Minimal detectable change values, normalized to mean values ranged from 1-50%. Step width mean and variability measures demonstrated the greatest response to perturbations with excellent between-session reliability and low minimum detectable change values. Orbital stability measures demonstrated specificity to perturbation direction and sensitivity with excellent between-session reliability and low minimum detectable change values. We observed substantially greater between-session reliability and lower minimum detectable change values for local stability measures than previously described which may be the result of averaging across trials within a session and using velocity versus acceleration data for reconstruction of state spaces. Across all perturbation types, temporal-spatial, orbital and local measures were the most reliable measures with the

  18. Reliability of quantitative real-time PCR for bacterial detection in cystic fibrosis airway specimens.

    Edith T Zemanick

    Full Text Available The cystic fibrosis (CF airway microbiome is complex; polymicrobial infections are common, and the presence of fastidious bacteria including anaerobes make culture-based diagnosis challenging. Quantitative real-time PCR (qPCR offers a culture-independent method for bacterial quantification that may improve diagnosis of CF airway infections; however, the reliability of qPCR applied to CF airway specimens is unknown. We sought to determine the reliability of nine specific bacterial qPCR assays (total bacteria, three typical CF pathogens, and five anaerobes applied to CF airway specimens. Airway and salivary specimens from clinically stable pediatric CF subjects were collected. Quantitative PCR assay repeatability was determined using triplicate reactions. Split-sample measurements were performed to measure variability introduced by DNA extraction. Results from qPCR were compared to standard microbial culture for Pseudomonas aeruginosa, Staphylococcus aureus, and Haemophilus influenzae, common pathogens in CF. We obtained 84 sputa, 47 oropharyngeal and 27 salivary specimens from 16 pediatric subjects with CF. Quantitative PCR detected bacterial DNA in over 97% of specimens. All qPCR assays were highly reproducible at quantities≥10(2 rRNA gene copies/reaction with coefficient of variation less than 20% for over 99% of samples. There was also excellent agreement between samples processed in duplicate. Anaerobic bacteria were highly prevalent and were detected in mean quantities similar to that of typical CF pathogens. Compared to a composite gold standard, qPCR and culture had variable sensitivities for detection of P. aeruginosa, S. aureus and H. influenzae from CF airway samples. By reliably quantifying fastidious airway bacteria, qPCR may improve our understanding of polymicrobial CF lung infections, progression of lung disease and ultimately improve antimicrobial treatments.

  19. Reliability analysis of onboard laser ranging systems for control systems by movement of spacecraft

    E. I. Starovoitov


    Full Text Available The purpose of this paper is to study and find the ways to improve the reliability of onboard laser ranging system (LRS used to control the spacecraft rendezvous and descent. The onboard LRS can be implemented with optical-mechanical scanner and without it. The paper analyses the key factors, which influence on the reliability of both LRS. Reliability of LRS is pretty much defined by the reliability of the laser source and its radiation mode. Solid-state diode-pumped lasers are primarily used as a radiation source. The radiation mode, which is defined by requirements for measurement errors of range and speed affect their reliability. The basic assumption is that the resource of solid state lasers is determined by the number pulses of pumping diodes. The paper investigates the influence of radiation mode of solid-state laser on the reliability function when measuring a passive spacecraft rendezvous dosing velocity using a differential method. With the measurement error, respectively, 10 m for range and 0.6 m/s for velocity a reliability function of 0.99 has been achieved. Reducing the measurement error of velocity to 0.5 m/s either results in reduced reliability function <0.99 or it is necessary to reduce the initial error of measurement range up to 3.5...5 m to correspond to the reliability function ≥ 0.995. For the optomechanical scanner-based LRS the maximum pulse repetition frequency versus the range has been obtained. This dependence has been used as a basis to define the reliability function. The paper investigates the influence of moving parts on the reliability of scanning LRS with sealed or unsealed optomechanical unit. As a result, it has been found that the exception of moving parts is justified provided that manufacturing the sealed optomechanical LRS unit is impossible. In this case, the reliability function increases from 0.99 to 0.9999. When sealing the opto-mechanical unit, the same increase in reliability is achieved through

  20. Mine Safety Detection System (MSDS)


    BLANK xiii LIST OF ACRONYMS AND ABBREVIATIONS Acronym Term ALMDS Airborne Laser -Mine Detection System AMCM Airborne Mine Countermeasure AoA...Streak Tube Imaging Laser ULCC Ultra Large Crude Carrier USN United States Navy UWIED Under Water Improvised Explosive Devices VLCC Very Large sonar, passive sonar, infra-red (IR) thermal imaging, LIDAR (Light Detection and Ranging), and the use of marine mammals ( dolphins and porpoises

  1. Reliability analysis of the bulk cargo loading system including dependent components

    Blokus-Roszkowska, Agnieszka


    In the paper an innovative approach to the reliability analysis of multistate series-parallel systems assuming their components' dependency is presented. The reliability function of a multistate series system with components dependent according to the local load sharing rule is determined. Linking these results for series systems with results for parallel systems with independent components, we obtain the reliability function of a multistate series-parallel system assuming dependence of components' departures from the reliability states subsets in series subsystem and assuming independence between these subsystems. As a particular case, the reliability function of a multistate series-parallel system composed of dependent components having exponential reliability functions is fixed. Theoretical results are applied practically to the reliability evaluation of a bulk cargo transportation system, which main area is to load bulk cargo on board the ships. The reliability function and other reliability characteristics of the loading system are determined in case its components have exponential reliability functions with interdependent departures rates from the subsets of their reliability states. Finally, the obtained results are compared with results for the bulk cargo transportation system composed of independent components.

  2. The intra-rater reliability of a revised 3-point grading system for accessory joint mobilizations.

    Ward, Jennifer; Hebron, Clair; Petty, Nicola J


    Joint mobilizations are often quantified using a 4-point grading system based on the physiotherapist's detection of resistance. It is suggested that the initial resistance to joint mobilizations is imperceptible to physiotherapists, but that at some point through range becomes perceptible, a point termed R1. Grades of mobilization traditionally hinge around this concept and are performed either before or after R1. Physiotherapists, however, show poor reliability in applying grades of mobilization. The definition of R1 is ambiguous and dependent on the skills of the individual physiotherapist. The aim of this study is to test a revised grading system where R1 is considered at the beginning of range, and the entire range, as perceived by the physiotherapists maximum force application, is divided into three, creating 3 grades of mobilization. Thirty-two post-registration physiotherapists and nineteen pre-registration students assessed end of range (point R2) and then applied 3 grades of AP mobilizations, over the talus, in an asymptomatic models ankle. Vertical forces were recorded through a force platform. Intra-class Correlation Coefficients, Standard Error of Measurement, and Minimal Detectable Change were calculated to explore intra-rater reliability on intra-day and inter-day testing. T-tests determined group differences. Intra-rater reliability was excellent for intra-day testing (ICC 0.96-0.97), and inter-day testing (ICC 0.85-0.93). No statistical difference was found between pre- and post-registration groups. Standardizing the definition of grades of mobilization, by moving R1 to the beginning of range and separating grades into thirds, results in excellent intra-rater reliability on intra-day and inter-day tests. 3b.

  3. Reactor scram experience for shutdown system reliability analysis. [BWR; PWR

    Edison, G.E.; Pugliese, S.L.; Sacramo, R.F.


    Scram experience in a number of operating light water reactors has been reviewed. The date and reactor power of each scram was compiled from monthly operating reports and personal communications with the operating plant personnel. The average scram frequency from ''significant'' power (defined as P/sub trip//P/sub max greater than/ approximately 20 percent) was determined as a function of operating life. This relationship was then used to estimate the total number of reactor trips from above approximately 20 percent of full power expected to occur during the life of a nuclear power plant. The shape of the scram frequency vs. operating life curve resembles a typical reliability bathtub curve (failure rate vs. time), but without a rising ''wearout'' phase due to the lack of operating data near the end of plant design life. For this case the failures are represented by ''bugs'' in the plant system design, construction, and operation which lead to scram. The number of scrams would appear to level out at an average of around three per year; the standard deviations from the mean value indicate an uncertainty of about 50 percent. The total number of scrams from significant power that could be expected in a plant designed for a 40-year life would be about 130 if no wearout phase develops near the end of life.

  4. Parameter Interval Estimation of System Reliability for Repairable Multistate Series-Parallel System with Fuzzy Data


    The purpose of this paper is to create an interval estimation of the fuzzy system reliability for the repairable multistate series–parallel system (RMSS). Two-sided fuzzy confidence interval for the fuzzy system reliability is constructed. The performance of fuzzy confidence interval is considered based on the coverage probability and the expected length. In order to obtain the fuzzy system reliability, the fuzzy sets theory is applied to the system reliability problem when dealing with uncertainties in the RMSS. The fuzzy number with a triangular membership function is used for constructing the fuzzy failure rate and the fuzzy repair rate in the fuzzy reliability for the RMSS. The result shows that the good interval estimator for the fuzzy confidence interval is the obtained coverage probabilities the expected confidence coefficient with the narrowest expected length. The model presented herein is an effective estimation method when the sample size is n ≥ 100. In addition, the optimal α-cut for the narrowest lower expected length and the narrowest upper expected length are considered. PMID:24987728

  5. Research on Reliability and Cost Integrated Optimization Algorithm of Construction Project Logistics System

    Xiaoping Bai


    Full Text Available The structure of the construction project logistics system is decomposed in detail; some uncertain factors affecting system reliability are analyzed. This paper applies the probability-influence coordinate graph to screen out the logistics subsystem that has great influence on system reliability under the conditions of occurring failure, and establishes an allocation model of the reliability index in construction project logistics system based on the restriction of cost, makes use of the presented model and algorithm to calculate the cost-based reliability, contrasts it with the index reliability assigned by the scoring method to the optimal distribution value of reliability index and the optimal cost. The presented detailed methods and steps can offer the meaningful reference for reliability optimization management of the logistics system in the construction project.

  6. Intelligent System for Worm Detection

    Tarek S. Sobh


    Full Text Available Worms are on the top of malware threats attacking computer system although of the evolution of worms detectiontechniques. Early detection of unknown worms is still a problem. This paper produce a method for detecting unknown wormsbased on local victim information. The proposed system uses Artificial Neural Network (ANN for classifying worm/ nonwormtraffic and predicting the percentage of infection in the infected network. This prediction can be used to support decisionmaking process for network administrator to respond quickly to worm propagation in an accurate procedure.

  7. Enhanced Reliability of Photovoltaic Systems with Energy Storage and Controls

    Manz, D.; Schelenz, O.; Chandra, R.; Bose, S.; de Rooij, M.; Bebic, J.


    This report summarizes efforts to reconfigure loads during outages to allow individual customers the opportunity to enhance the reliability of their electric service through the management of their loads, photovoltaics, and energy storage devices.

  8. Reliable functioning of a system of relay protection

    Velicescu, C.; Ivascu, C.; Nicolaescu, A.


    An examination is made of the networks of average voltage with neutral connected to the ground through a current-limiting resistor. The reliability is determined for the relay protection of these networks.

  9. An Integrated Fault Tolerant Robotic Controller System for High Reliability and Safety

    Marzwell, Neville I.; Tso, Kam S.; Hecht, Myron


    This paper describes the concepts and features of a fault-tolerant intelligent robotic control system being developed for applications that require high dependability (reliability, availability, and safety). The system consists of two major elements: a fault-tolerant controller and an operator workstation. The fault-tolerant controller uses a strategy which allows for detection and recovery of hardware, operating system, and application software failures.The fault-tolerant controller can be used by itself in a wide variety of applications in industry, process control, and communications. The controller in combination with the operator workstation can be applied to robotic applications such as spaceborne extravehicular activities, hazardous materials handling, inspection and maintenance of high value items (e.g., space vehicles, reactor internals, or aircraft), medicine, and other tasks where a robot system failure poses a significant risk to life or property.

  10. Quickest detection in coupled systems

    Hadjiliadis, Olympia; Poor, H Vincent


    This work considers the problem of quickest detection of signals in a coupled system of N sensors, which receive continuous sequential observations from the environment. It is assumed that the signals, which are modeled a general Ito processes, are coupled across sensors, but that their onset times may differ from sensor to sensor. The objective is the optimal detection of the first time at which any sensor in the system receives a signal. The problem is formulated as a stochastic optimization problem in which an extended average Kullback- Leibler divergence criterion is used as a measure of detection delay, with a constraint on the mean time between false alarms. The case in which the sensors employ cumulative sum (CUSUM) strategies is considered, and it is proved that the minimum of N CUSUMs is asymptotically optimal as the mean time between false alarms increases without bound.


    Choi, Uimin

    As power electronic systems have gradually gained an important status in a wide range of industrial applications, there are increasing demands to improve the reliability and robustness of power electronic systems. The power electronic systems consist of various components, and among them, power...... that kills IGBT modules. Therefore, in order to improve the reliability of power electronic systems, reliability research on reliability-critical components regarding the major critical stressors are needed. In this PhD project, various researches on reliability of the IGBT module are performed from...... 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...

  12. Differential Evolution Based Intelligent System State Search Method for Composite Power System Reliability Evaluation

    Bakkiyaraj, Ashok; Kumarappan, N.


    This paper presents a new approach for evaluating the reliability indices of a composite power system that adopts binary differential evolution (BDE) algorithm in the search mechanism to select the system states. These states also called dominant states, have large state probability and higher loss of load curtailment necessary to maintain real power balance. A chromosome of a BDE algorithm represents the system state. BDE is not applied for its traditional application of optimizing a non-linear objective function, but used as tool for exploring more number of dominant states by producing new chromosomes, mutant vectors and trail vectors based on the fitness function. The searched system states are used to evaluate annualized system and load point reliability indices. The proposed search methodology is applied to RBTS and IEEE-RTS test systems and results are compared with other approaches. This approach evaluates the indices similar to existing methods while analyzing less number of system states.

  13. An indirect technique for estimating reliability of analog and mixed-signal systems during operational life

    Khan, M.A.; Kerkhoff, Hans G.


    Reliability of electronic systems has been thoroughly investigated in literature and a number of analytical approaches at the design stage are already available via examination of the circuit-level reliability effects based on device-level models. Reliability estimation during operational life of an

  14. An indirect technique for estimating reliability of analog and mixed-signal systems during operational life

    Khan, Muhammad Aamir; Kerkhoff, Hans G.


    Reliability of electronic systems has been thoroughly investigated in literature and a number of analytical approaches at the design stage are already available via examination of the circuit-level reliability effects based on device-level models. Reliability estimation during operational life of an

  15. System for detecting microbial contamination

    Gerritse, J.; Groenestijn, J.W.; Zegers, N.D.


    The present invention relates to a system for detecting microbial contamination of a liquid specimen comprising a device for concentrating micro-organisms from a liquid specimen, having (i) a hypobaric chamber, (ii) a filter housing comprising a liquid-permeable bed of an adsorbent material and adap

  16. Portable Microleak-Detection System

    Rivers, H. Kevin; Sikora, Joseph G.; Sankaran, Sankara N.


    The figure schematically depicts a portable microleak-detection system that has been built especially for use in testing hydrogen tanks made of polymer-matrix composite materials. (As used here, microleak signifies a leak that is too small to be detectable by the simple soap-bubble technique.) The system can also be used to test for microleaks in tanks that are made of other materials and that contain gases other than hydrogen. Results of calibration tests have shown that measurement errors are less than 10 percent for leak rates ranging from 0.3 to 200 cm3/min. Like some other microleak-detection systems, this system includes a vacuum pump and associated plumbing for sampling the leaking gas, and a mass spectrometer for analyzing the molecular constituents of the gas. The system includes a flexible vacuum chamber that can be attached to the outer surface of a tank or other object of interest that is to be tested for leakage (hereafter denoted, simply, the test object). The gas used in a test can be the gas or vapor (e.g., hydrogen in the original application) to be contained by the test object. Alternatively, following common practice in leak testing, helium can be used as a test gas. In either case, the mass spectrometer can be used to verify that the gas measured by the system is the test gas rather than a different gas and, hence, that the leak is indeed from the test object.

  17. Semi autonomous mine detection system

    Douglas Few; Roelof Versteeg; Herman Herman


    CMMAD is a risk reduction effort for the AMDS program. As part of CMMAD, multiple instances of semi autonomous robotic mine detection systems were created. Each instance consists of a robotic vehicle equipped with sensors required for navigation and marking, a countermine sensors and a number of integrated software packages which provide for real time processing of the countermine sensor data as well as integrated control of the robotic vehicle, the sensor actuator and the sensor. These systems were used to investigate critical interest functions (CIF) related to countermine robotic systems. To address the autonomy CIF, the INL developed RIK was extended to allow for interaction with a mine sensor processing code (MSPC). In limited field testing this system performed well in detecting, marking and avoiding both AT and AP mines. Based on the results of the CMMAD investigation we conclude that autonomous robotic mine detection is feasible. In addition, CMMAD contributed critical technical advances with regard to sensing, data processing and sensor manipulation, which will advance the performance of future fieldable systems. As a result, no substantial technical barriers exist which preclude – from an autonomous robotic perspective – the rapid development and deployment of fieldable systems.

  18. Semi autonomous mine detection system

    Few, Doug; Versteeg, Roelof; Herman, Herman


    CMMAD is a risk reduction effort for the AMDS program. As part of CMMAD, multiple instances of semi autonomous robotic mine detection systems were created. Each instance consists of a robotic vehicle equipped with sensors required for navigation and marking, countermine sensors and a number of integrated software packages which provide for real time processing of the countermine sensor data as well as integrated control of the robotic vehicle, the sensor actuator and the sensor. These systems were used to investigate critical interest functions (CIF) related to countermine robotic systems. To address the autonomy CIF, the INL developed RIK was extended to allow for interaction with a mine sensor processing code (MSPC). In limited field testing this system performed well in detecting, marking and avoiding both AT and AP mines. Based on the results of the CMMAD investigation we conclude that autonomous robotic mine detection is feasible. In addition, CMMAD contributed critical technical advances with regard to sensing, data processing and sensor manipulation, which will advance the performance of future fieldable systems. As a result, no substantial technical barriers exist which preclude - from an autonomous robotic perspective - the rapid development and deployment of fieldable systems.

  19. Reliability and performance evaluation of systems containing embedded rule-based expert systems

    Beaton, Robert M.; Adams, Milton B.; Harrison, James V. A.


    A method for evaluating the reliability of real-time systems containing embedded rule-based expert systems is proposed and investigated. It is a three stage technique that addresses the impact of knowledge-base uncertainties on the performance of expert systems. In the first stage, a Markov reliability model of the system is developed which identifies the key performance parameters of the expert system. In the second stage, the evaluation method is used to determine the values of the expert system's key performance parameters. The performance parameters can be evaluated directly by using a probabilistic model of uncertainties in the knowledge-base or by using sensitivity analyses. In the third and final state, the performance parameters of the expert system are combined with performance parameters for other system components and subsystems to evaluate the reliability and performance of the complete system. The evaluation method is demonstrated in the context of a simple expert system used to supervise the performances of an FDI algorithm associated with an aircraft longitudinal flight-control system.

  20. Reliability Modeling and Optimization Strategy for Manufacturing System Based on RQR Chain

    Yihai He


    Full Text Available Accurate and dynamic reliability modeling for the running manufacturing system is the prerequisite to implement preventive maintenance. However, existing studies could not output the reliability value in real time because their abandonment of the quality inspection data originated in the operation process of manufacturing system. Therefore, this paper presents an approach to model the manufacturing system reliability dynamically based on their operation data of process quality and output data of product reliability. Firstly, on the basis of importance explanation of the quality variations in manufacturing process as the linkage for the manufacturing system reliability and product inherent reliability, the RQR chain which could represent the relationships between them is put forward, and the product qualified probability is proposed to quantify the impacts of quality variation in manufacturing process on the reliability of manufacturing system further. Secondly, the impact of qualified probability on the product inherent reliability is expounded, and the modeling approach of manufacturing system reliability based on the qualified probability is presented. Thirdly, the preventive maintenance optimization strategy for manufacturing system driven by the loss of manufacturing quality variation is proposed. Finally, the validity of the proposed approach is verified by the reliability analysis and optimization example of engine cover manufacturing system.

  1. A new approach to real-time reliability analysis of transmission system using fuzzy Markov model

    Tanrioven, M.; Kocatepe, C. [University of Yildiz Technical, Istanbul (Turkey). Dept. of Electrical Engineering; Wu, Q.H.; Turner, D.R.; Wang, J. [Liverpool Univ. (United Kingdom). Dept. of Electrical Engineering and Economics


    To date the studies of power system reliability over a specified time period have used average values of the system transition rates in Markov techniques. [Singh C, Billinton R. System reliability modeling and evaluation. London: Hutchison Educational; 1977]. However, the level of power systems reliability varies from time to time due to weather conditions, power demand and random faults [Billinton R, Wojczynski E. Distributional variation of distribution system reliability indices. IEEE Trans Power Apparatus Systems 1985; PAS-104(11):3152-60]. It is essential to obtain an estimate of system reliability under all environmental and operating conditions. In this paper, fuzzy logic is used in the Markov model to describe both transition rates and temperature-based seasonal variations, which identifies multiple weather conditions such as normal, less stormy, very stormy, etc. A three-bus power system model is considered to determine the variation of system reliability in real-time, using this newly developed fuzzy Markov model (FMM). The results cover different aspects such as daily and monthly reliability changes during January and August. The reliability of the power transmission system is derived as a function of augmentation in peak load level. Finally the variation of the system reliability with weather conditions is determined. (author)

  2. A novel method for rapid and reliable detection of complex vertebral malformation and bovine leukocyte adhesion deficiency in Holstein cattle

    Zhang Yi


    Full Text Available Abstract Background Complex vertebral malformation (CVM and bovine leukocyte adhesion deficiency (BLAD are two autosomal recessive lethal genetic defects frequently occurring in Holstein cattle, identifiable by single nucleotide polymorphisms. The objective of this study is to develop a rapid and reliable genotyping assay to screen the active Holstein sires and determine the carrier frequency of CVM and BLAD in Chinese dairy cattle population. Results We developed real-time PCR-based assays for discrimination of wild-type and defective alleles, so that carriers can be detected. Only one step was required after the DNA extraction from the sample and time consumption was about 2 hours. A total of 587 Chinese Holstein bulls were assayed, and fifty-six CVM-carriers and eight BLAD-carriers were identified, corresponding to heterozygote carrier frequencies of 9.54% and 1.36%, respectively. The pedigree analysis showed that most of the carriers could be traced back to the common ancestry, Osborndale Ivanhoe for BLAD and Pennstate Ivanhoe Star for CVM. Conclusions These results demonstrate that real-time PCR is a simple, rapid and reliable assay for BLAD and CVM defective allele detection. The high frequency of the CVM allele suggests that implementing a routine testing system is necessary to gradually eradicate the deleterious gene from the Chinese Holstein population.

  3. Reliability of piping system components. Volume 1: Piping reliability - A resource document for PSA applications

    Nyman, R.; Erixon, S.; Tomic, B.; Lydell, B.


    SKI has undertaken a multi-year research project to establish a comprehensive passive component failure database, validate failure rate parameter estimates and establish a model framework for integrating passive component failures in existing PSAs. Phase 1 of the project produced a relational database on worldwide piping system failure events in the nuclear and chemical industries. This phase 2 report gives a graphical presentation of piping system operating experience, and compares key failure mechanisms in commercial nuclear power plants and chemical process industry. Inadequacies of traditional PSA methodology are addressed, with directions for PSA methodology enhancements. A data-driven-and-systems-oriented analysis approach is proposed to enable assignment of unique identities to risk-significant piping system component failures. Sufficient operating experience does exist to generate quality data on piping failures. Passive component failures should be addressed by today`s PSAs to allow for aging analysis and effective, on-line risk management. 111 refs, 36 figs, 20 tabs.

  4. Reliability of the Beam Loss Monitors System for the Large Hadron Collider at CERN

    Guaglio, G; Santoni, C


    The energy stored in the Large Hadron Collider is unprecedented. The impact of the beam particles can cause severe damage on the superconductive magnets, resulting in significant downtime for repairing. The Beam Loss Monitors System (BLMS) detects the secondary particles shower of the lost beam particles and initiates the extraction of the beam before any serious damage to the equipment can occur. This thesis defines the BLMS specifications in term of reliability. The main goal is the design of a system minimizing both the probability to not detect a dangerous loss and the number of false alarms generated. The reliability theory and techniques utilized are described. The prediction of the hazard rates, the testing procedures, the Failure Modes Effects and Criticalities Analysis and the Fault Tree Analysis have been used to provide an estimation of the probability to damage a magnet, of the number of false alarms and of the number of generated warnings. The weakest components in the BLMS have been pointed out....

  5. Reliability evaluation of distribution systems containing renewable distributed generations

    Alkuhayli, Abdulaziz Abddullah

    Reliability evaluation of distribution networks, including islanded microgrid cases, is presented. The Monte Carlo simulation algorithm is applied to a test network. The network includes three types of distributed energy resources solar photovoltaic (PV), wind turbine (WT) and gas turbine (GT). These distributed generators contribute to supply part of the load during grid-connected mode, but supply the entire load during islanded microgrid operation. PV and WT stochastic models have been used to simulate the randomness of these resources. This study shows that the implementation of distributed generations can improve the reliability of the distribution networks.

  6. Analysis of muscle fiber conduction velocity enables reliable detection of surface EMG crosstalk during detection of nociceptive withdrawal reflexes.

    Jensen, Michael Brun; Manresa, José Alberto Biurrun; Frahm, Ken Steffen; Andersen, Ole Kæseler


    .96) for the tibialis anterior and soleus muscles. This study investigated the negative effect of electrical crosstalk during reflex detection and revealed that the use of a previously validated scoring criterion may result in poor specificity due to crosstalk. The excellent performance of the developed methodology in the presence of crosstalk shows that assessment of muscle fiber conduction velocity allows reliable detection of EMG crosstalk during reflex detection.

  7. Diacetin, a reliable cue and private communication channel in a specialized pollination system.

    Schäffler, Irmgard; Steiner, Kim E; Haid, Mark; van Berkel, Sander S; Gerlach, Günter; Johnson, Steven D; Wessjohann, Ludger; Dötterl, Stefan


    The interaction between floral oil secreting plants and oil-collecting bees is one of the most specialized of all pollination mutualisms. Yet, the specific stimuli used by the bees to locate their host flowers have remained elusive. This study identifies diacetin, a volatile acetylated glycerol, as a floral signal compound shared by unrelated oil plants from around the globe. Electrophysiological measurements of antennae and behavioural assays identified diacetin as the key volatile used by oil-collecting bees to locate their host flowers. Furthermore, electrophysiological measurements indicate that only oil-collecting bees are capable of detecting diacetin. The structural and obvious biosynthetic similarity between diacetin and associated floral oils make it a reliable cue for oil-collecting bees. It is easily perceived by oil bees, but can't be detected by other potential pollinators. Therefore, diacetin represents the first demonstrated private communication channel in a pollination system.

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

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


    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...


    Yao Chengyu; Zhao Jingyi


    To overcome the design limitations of traditional hydraulic control system for synthetic rubber press and such faults as high fault rate, low reliability, high energy-consuming and which always led to shutting down of post-treatment product line for synthetic rubber, brand-new hydraulic system combining with PC control and two-way cartridge valves for the press is developed, whose reliability is analyzed, reliability model of the hydraulic system for the press is established by analyzing processing steps, and reliability simulation of each step and the whole system is carried out by software MATLAB, which is verified through reliability test. The fixed time test has proved not that theory analysis is sound, but the system has characteristics of reasonable design and high reliability,and can lower the required power supply and operational energy cost.

  10. A discussion of system reliability and the relative importance of pumps and valves to overall system availability

    Poole, A.B. [Oak Ridge National Lab., TN (United States)


    An analysis was undertaken to establish preliminary trends for how component aging can effect failure rates for swing check valves, centrifugal pumps and motor operated valves. These failure rate trends were evaluated over time and linear aging rate models established. The failure rate models were then used with classic reliability theories to estimate reliability as a function of operating time. Reliability theory was also used to establish a simple system reliability model. Using the system model, the relative importance of pumps and valves to the overall system reliability were studied. Conclusions were established relative to overall system availability over time and the relative unavailabilities of the various components studied.


    Assessment of reliability and safety of a manufacturing system with sequential failures is an important issue in industry, since the reliability and safety of the system depend not only on all failed states of system components, but also on the sequence of occurrences of those...

  12. Interactive Reliability-Based Optimization of Structural Systems

    Pedersen, Claus

    In order to introduce the basic concepts within the field of reliability-based structural optimization problems, this chapter is devoted to a brief outline of the basic theories. Therefore, this chapter is of a more formal nature and used as a basis for the remaining parts of the thesis. In secti...

  13. Reliability and validity of triage systems in paediatric emergency care

    M. van Veen (Mirjam); H.A. Moll (Henriëtte)


    textabstractBackground. Triage in paediatric emergency care is an important tool to prioritize seriously ill children. Triage can also be used to identify patients who do not need urgent care and who can safely wait. The aim of this review was to provide an overview of the literature on reliability

  14. 75 FR 72664 - System Personnel Training Reliability Standards


    ... Standards to address certain issues identified by the Commission. At issue in the immediate proceeding are... PER Reliability Standards filed by NERC in this proceeding as just, reasonable, not unduly... realistically replicate the entity's own topology and operating conditions; i.e., to require...

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

    Rabiti, Cristian; Alfonsi, Andrea; Huang, Dongli; Gleicher, Frederick; Wang, Bei; Adbel-Khalik, Hany S.; Pascucci, Valerio; Smith, Curtis L.


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

  16. Visual acuity measures do not reliably detect childhood refractive error--an epidemiological study.

    Lisa O'Donoghue

    Full Text Available PURPOSE: To investigate the utility of uncorrected visual acuity measures in screening for refractive error in white school children aged 6-7-years and 12-13-years. METHODS: The Northern Ireland Childhood Errors of Refraction (NICER study used a stratified random cluster design to recruit children from schools in Northern Ireland. Detailed eye examinations included assessment of logMAR visual acuity and cycloplegic autorefraction. Spherical equivalent refractive data from the right eye were used to classify significant refractive error as myopia of at least 1DS, hyperopia as greater than +3.50DS and astigmatism as greater than 1.50DC, whether it occurred in isolation or in association with myopia or hyperopia. RESULTS: Results are presented from 661 white 12-13-year-old and 392 white 6-7-year-old school-children. Using a cut-off of uncorrected visual acuity poorer than 0.20 logMAR to detect significant refractive error gave a sensitivity of 50% and specificity of 92% in 6-7-year-olds and 73% and 93% respectively in 12-13-year-olds. In 12-13-year-old children a cut-off of poorer than 0.20 logMAR had a sensitivity of 92% and a specificity of 91% in detecting myopia and a sensitivity of 41% and a specificity of 84% in detecting hyperopia. CONCLUSIONS: Vision screening using logMAR acuity can reliably detect myopia, but not hyperopia or astigmatism in school-age children. Providers of vision screening programs should be cognisant that where detection of uncorrected hyperopic and/or astigmatic refractive error is an aspiration, current UK protocols will not effectively deliver.

  17. A simple and reliable methodology to detect egg white in art samples

    Michela Gambino; Francesca Cappitelli; Cristina Cattò; Aristodemo Carpen; Pamela Principi; Lisa Ghezzi; Ilaria Bonaduce; Eugenio Galano; Pietro Pucci; Leila Birolo; Federica Villa; Fabio Forlani


    A protocol for a simple and reliable dot-blot immunoassay was developed and optimized to test work of art samples for the presence of specific proteinaceus material (i.e. ovalbumin-based). The analytical protocol has been extensively set up with respect, among the other, to protein extraction conditions, to densitometric analysis and to the colorimetric reaction conditions. Feasibility evaluation demonstrated that a commercial scanner and a free image analysis software can be used for the data acquisition and elaboration, thus facilitating the application of the proposed protocol to commonly equipped laboratories and to laboratories of museums and conservation centres. The introduction of method of standard additions in the analysis of fresh and artificially aged laboratory-prepared samples, containing egg white and various pigments, allowed us to evaluate the matrix effect and the effect of sample aging and to generate threshold density values useful for the detection of ovalbumin in samples from ancient works of art. The efficacy of the developed dot-blot immunoassay was proved testing microsamples from 13th–16th century mural paintings of Saint Francesco Church in Lodi (Italy). Despite the aging, the altered conditions of conservation, the complex matrix, and the micro-size of samples, the presence of ovalbumin was detected in all those mural painting samples where mass-spectrometry-based proteomic analysis unambiguously detected ovalbumin peptides.

  18. Lightning Protection and Detection System

    Dudley, Kenneth L. (Inventor); Szatkowski, George N. (Inventor); Woodard, Marie (Inventor); Nguyen, Truong X. (Inventor); Ely, Jay J. (Inventor); Wang, Chuantong (Inventor); Mielnik, John J. (Inventor); Koppen, Sandra V. (Inventor); Smith, Laura J. (Inventor)


    A lightning protection and detection system includes a non-conductive substrate material of an apparatus; a sensor formed of a conductive material and deposited on the non-conductive substrate material of the apparatus. The sensor includes a conductive trace formed in a continuous spiral winding starting at a first end at a center region of the sensor and ending at a second end at an outer corner region of the sensor, the first and second ends being open and unconnected. An electrical measurement system is in communication with the sensor and receives a resonant response from the sensor, to perform detection, in real-time, of lightning strike occurrences and damage therefrom to the sensor and the non-conductive substrate material.

  19. 2002 reliability report on the French power system; Bilan 2002 de la surete du systeme electrique francais



    Ensuring the reliability of the power system is one of the main responsibilities entrusted to RTE, the French transmission system operator, by the Act of February 10, 2000. Reliability must be maintained, both now and in the future. This means that RTE is required to: ensure the normal operation of the power system, limit the number of incidents and avoid major incidents, limit the consequences of major incidents when they do occur. By publishing a yearly reliability report on the French power system, RTE is clearly showing its ambition to encourage long-term supervision of all aspects of system reliability development. By this approach, RTE's intention is to help develop a reliability culture, by all the actors concerned (both RTE and network users) more aware of their role in establishing reliability, and by promoting reliability issues and comparisons with international transmission system operator associations (UCTE , ETSO ). The annual reliability report is drawn up around the following themes: a broad overview of changes in the internal and external environment that have implications for reliability, developments in the various elements that make up the reliability referential during the course of the year, developments on measures aimed at promoting reliability, in terms of equipment, organisation and human resources, lessons learned from events that took place over the year, the presentation of reliability-related indicators, RTE's control loop, and the developments under way at present.

  20. Optical detection in microfluidic systems

    Mogensen, Klaus Bo; Kutter, Jörg Peter


    Optical detection schemes continue to be favoured for measurements in microfluidic systems. A selection of the latest progress mainly within the last two years is critically reviewed. Emphasis is on integrated solutions, such as planar waveguides, coupling schemes to the outside world, evanescent...... to ease commercialisation of the devices. This work will hopefully result in more commercial products that benefit from integrated optics, because the impact on commercial devices so far has been modest....

  1. Software reliability - Measures and effects in flight critical digital avionics systems

    Dunn, William R.


    The paper discusses software reliability as it applies particularly to design and evaluation of flight-critical digital avionics systems. Measures of software reliability, measurement methods and reliability (macro-) models are discussed. Recent work assessing their accuracy in predicting software errors in 'fly-by-wire' Newtonian applications is presented. Additional, detailed topics are discussed including software error distributions (e.g. catastrophic vs. noncatastrophic) and the effects of system growth/maturity on reliability improvement. In practical flight-critical digital applications, software reliability improvement is sought through use of parallel, redundant software (i.e. N-version programming) or backup software that can be invoked in the event of (primary) software failure. Achievable reliability levels are however highly sensitive to common-mode specification and programming errors. Recent data correlating these errors with net software reliability are discussed.

  2. Probabilistic Approach to System Reliability of Mechanism with Correlated Failure Models

    Xianzhen Huang


    Full Text Available In this paper, based on the kinematic accuracy theory and matrix-based system reliability analysis method, a practical method for system reliability analysis of the kinematic performance of planar linkages with correlated failure modes is proposed. The Taylor series expansion is utilized to derive a general expression of the kinematic performance errors caused by random variables. A proper limit state function (performance function for reliability analysis of the kinematic performance of planar linkages is established. Through the reliability theory and the linear programming method the upper and lower bounds of the system reliability of planar linkages are provided. In the course of system reliability analysis, the correlation of different failure modes is considered. Finally, the practicality, efficiency, and accuracy of the proposed method are shown by a numerical example.

  3. Using PoF models to predict system reliability considering failure collaboration

    Zhiguo Zeng


    Full Text Available Existing Physics-of-Failure-based (PoF-based system reliability prediction methods are grounded on the independence assumption, which overlooks the dependency among the components. In this paper, a new type of dependency, referred to as failure collaboration, is introduced and considered in reliability predictions. A PoF-based model is developed to describe the failure behavior of systems subject to failure collaboration. Based on the developed model, the Bisection-based Reliability Analysis Method (BRAM is exploited to calculate the system reliability. The developed methods are applied to predicting the reliability of a Hydraulic Servo Actuator (HSA. The results demonstrate that the developed methods outperform the traditional PoF-based reliability prediction methods when applied to systems subject to failure collaboration.

  4. System Reliability Evaluation of Data Transmission in Commercial Banks with Multiple Branches

    Yi-Kuei Lin


    Full Text Available The main purpose of this paper is to assess the system reliability of electronic transaction data transmissions made by commercial banks in terms of stochastic flow network. System reliability is defined as the probability of demand satisfaction and it can be used to measure quality of service. In this paper, we study the system reliability of data transmission from the headquarters of a commercial bank to its multiple branches. The network structure of the bank and the probability of successful data transmission are obtained through the collection of real data. The system reliability, calculated using the minimal path method and the recursive sum of disjoint products algorithm, provides banking managers with a view to comprehend the current state of the entire system. Besides, the system reliability can be used not only as a measurement of quality of service, but also an improvement reference of the system by adopting sensitivity analysis.

  5. Gastric Cancer Regional Detection System.

    Ural, Berkan; Hardalaç, Fırat; Serhatlioğlu, Selami; İlhan, Mustafa Necmi


    In this study, a novel system was created to localize cancerous regions for stomach images which were taken with computed tomography(CT). The aim was to determine the coordinates of cancerous regions which spread in the stomach area in the color space with using this system. Also, to limit these areas with a high accuracy ratio and to feedback to the user of this system were the other objectives. This integration was performed with using energy mapping, analysis methods and multiple image processing methods and the system which was consisted from these advanced algorithms was appeared. For this work, in the range of 25-40 years and when gender discrimination was insignificant, 30 volunteer patients were chosen. During the formation of the system, to exalt the accuracy to the maximum level, 2 main stages were followed up. First, in the system, advanced image processing methods were processed between each other and obtained data were studied. Second, in the system, FFT and Log transformations were used respectively for the first two cases, then these transformations were used together for the third case. For totally three cases, energy distribution and DC energy intensity analysis were done and the performance of this system was investigated. Finally, with using the system's unique algorithms, a non-invasive method was achieved to detect the gastric cancer and when FFT and Log transformation were used together, the maximum success rate was obtained and this rate was calculated as 83,3119 %.

  6. The Autonomous Pathogen Detection System

    Dzenitis, J M; Makarewicz, A J


    We developed, tested, and now operate a civilian biological defense capability that continuously monitors the air for biological threat agents. The Autonomous Pathogen Detection System (APDS) collects, prepares, reads, analyzes, and reports results of multiplexed immunoassays and multiplexed PCR assays using Luminex{copyright} xMAP technology and flow cytometer. The mission we conduct is particularly demanding: continuous monitoring, multiple threat agents, high sensitivity, challenging environments, and ultimately extremely low false positive rates. Here, we introduce the mission requirements and metrics, show the system engineering and analysis framework, and describe the progress to date including early development and current status.

  7. A Generalized Model for Electrical Power Distribution Feeders’ Contributions to System Reliability Indices

    Ganiyu A. Ajenikoko


    Full Text Available Reliability indices are parametric quantities used to assess the performance levels of electrical power distribution systems. In this work, a generalized quadratic model is developed for electrical power distribution system contributions to system reliability indices using Ikeja, Port-Harcourt, Kaduna and Kano distribution system feeders as case studies. The mean System Average Interruption Duration Index (SAIDI, System Average Interruption Frequency Index (SAIFI and Customer Average Interruption Duration Index (CAIDI contributions to system reliability indices for Ikeja, Port-Harcourt, Kaduna and Kano distribution systems were 0.0033, 0.0026, 0.0033 and 0.0018 respectively due to the fact that a prolonged period of interruptions was recorded on most of the feeders attached to Port-Harcourt and Kano distribution systems making them to be less reliable compared to Ikeja and Kaduna distribution systems. The generalized Quadratic model forms a basis for a good design, planning and maintenance of distribution systems at large.

  8. MONITORING OF LARGE INSTABLE AREAS: system reliability and new tools.

    Leandro, G.; Mucciarelli, M.; Pellicani, R.; Spilotro, G.


    The monitoring of unstable or potentially unstable areas is a necessary operation every time you can not remove the conditions of risk and apply to mitigation measures. In Italian Apennine regions there are many urban or extra-urban areas affected by instability, for which it is impracticable to remove hazard conditions, because of size and cost problems. The technological evolution exportable to the field of land instability monitoring is particularly lively and allows the use of warning systems unthinkable just few years ago. However, the monitoring of unstable or potentially unstable areas requires a very great knowledge of the specific problems, without which the reliability of the system may be dangerously overestimated. The movement may arise, indeed, in areas not covered by instrumentation, or covered with vegetation that prevents the acquisition of both reflected signals in the multi-beam laser techniques and radar signals. Environmental conditions (wind, concentrated sources of light, temperature changes, presence of animals) may also invalidate the accuracy of the measures, by introducing modulations or disturbance at a level well above the threshold of alarm signal, leading consequently to raise the values of the warning threshold. The Authors have gained long experience with the observation and monitoring of some large landslides in the Southern Apennine (Aliano, Buoninventre, Calciano, Carlantino, etc.) and unstable areas also at regional scale. One of the most important experiences is about the case of landslides of extensive areas, where unstable and stables zones coexist along transverse and longitudinal axis. In many of these cases you need the accurate control of the movement at selected points to evaluate the trend of displacement velocity, which can be achieved by means of a single-beam laser. The control of these movements, however, does not provide information on stress pattern into the stable areas. Among the sensitive precursors, acoustic

  9. Ultra-reliable computer systems: an integrated approach for application in reactor safety systems

    Chisholm, G.H.


    Improvements in operation and maintenance of nuclear reactors can be realized with the application of computers in the reactor control systems. In the context of this paper a reactor control system encompasses the control aspects of the Reactor Safety System (RSS). Equipment qualification for application in reactor safety systems requires a rigorous demonstration of reliability. For the purpose of this paper, the reliability demonstration will be divided into two categories. These categories are demonstrations of compliance with respect to (a) environmental; and (b) functional design constrains. This paper presents an approach for the determination of computer-based RSS respective to functional design constraints only. It is herein postulated that the design for compliance with environmental design constraints is a reasonably definitive problem and within the realm of available technology. The demonstration of compliance with design constraints respective to functionality, as described herein, is an extension of available technology and requires development.

  10. Reliability of an occlusal and nonocclusal tooth wear grading system: clinical use versus dental cast assessment.

    Wetselaar, Peter; Lobbezoo, Frank; Koutris, Michail; Visscher, Corine M; Naeije, Machiel


    The reliability of a newly developed tooth wear grading system was assessed both clinically and on dental casts by two observers using 20 participants. The reliability of clinical occlusal/incisal tooth wear grading was fair-to-good to excellent, while that of most of the clinical nonocclusal/nonincisal grades was at least fair-to-good. Dental cast assessment frequently yielded poor reliabilities, especially for nonocclusal/nonincisal surfaces. Hence, occlusal/incisal wear could be graded more reliably than nonocclusal/nonincisal wear, while the clinical assessment of tooth wear was more reliable than the grading of dental casts.

  11. Design for Reliability of Power Electronics in Renewable Energy Systems

    Ma, Ke; Yang, Yongheng; Wang, Huai


    Power electronics is the enabling technology for maximizing the power captured from renewable electrical generation, e.g., the wind and solar technology, and also for an efficient integration into the grid. Therefore, it is important that the power electronics are reliable and do not have too many...... failures during operation which otherwise will increase cost for operation, maintenance and reputation. Typically, power electronics in renewable electrical generation has to be designed for 20–30 years of operation, and in order to do that, it is crucial to know about the mission profile of the power...... and demonstrate how the power electronics is loaded under different stressors. Further, some systematic methods to design the power electronics technology for reliability will be given and demonstrated with two cases—one is a wind power and the other is photovoltaic application....

  12. Reliability of an Integrated Ultrasound and Stereophotogrammetric System for Lower Limb Anatomical Characterisation

    Frederick Greatrex


    Full Text Available Background. Lower extremity analysis for preoperative total knee and hip arthroplasty routines can increase surgery success rate and hence reduce associated costs. Current tools are limited by being invasive, limited to supine analysis, or too expensive. This study aimed to propose and validate a device, OrthoPilot®, based on the combined use of a stereophotogrammetric and ultrasound system which can in vivo and noninvasively measure varus/valgus, flexion/extension, femur and tibia torsion, and femur and tibia lengths. Methods. A phantom was measured by four operators to determine the resolution of the system. Interoperator variability was measured on three operators who measured the above six variables on both legs of three subjects in standing and supine positions. Intraoperator variability was assessed on data from three repeats from 9 subjects (18 legs. Results. All 6 variables were reliably detected on a phantom, with a resolution of 1 mm and 0.5°. Inter- and intraoperator consistency was observed for varus/valgus, flexion/extension, and length measurements on the healthy subjects in standing and supine positions (all ICC > 0.93. For torsion measurements, there was a considerable variation. Conclusion. The proposed system, when used on healthy subjects, allowed reliable measurements of key parameters for preoperative procedures in both supine and standing positions. Accuracy testing and further validation on patient populations will be the next step toward its clinical adoption.

  13. Reliability assessment of null allele detection: inconsistencies between and within different methods.

    Dąbrowski, M J; Pilot, M; Kruczyk, M; Żmihorski, M; Umer, H M; Gliwicz, J


    Microsatellite loci are widely used in population genetic studies, but the presence of null alleles may lead to biased results. Here, we assessed five methods that indirectly detect null alleles and found large inconsistencies among them. Our analysis was based on 20 microsatellite loci genotyped in a natural population of Microtus oeconomus sampled during 8 years, together with 1200 simulated populations without null alleles, but experiencing bottlenecks of varying duration and intensity, and 120 simulated populations with known null alleles. In the natural population, 29% of positive results were consistent between the methods in pairwise comparisons, and in the simulated data set, this proportion was 14%. The positive results were also inconsistent between different years in the natural population. In the null-allele-free simulated data set, the number of false positives increased with increased bottleneck intensity and duration. We also found a low concordance in null allele detection between the original simulated populations and their 20% random subsets. In the populations simulated to include null alleles, between 22% and 42% of true null alleles remained undetected, which highlighted that detection errors are not restricted to false positives. None of the evaluated methods clearly outperformed the others when both false-positive and false-negative rates were considered. Accepting only the positive results consistent between at least two methods should considerably reduce the false-positive rate, but this approach may increase the false-negative rate. Our study demonstrates the need for novel null allele detection methods that could be reliably applied to natural populations.

  14. Reliability of a Large Series-parallel System in Variable Operating Conditions

    Joanna Soszynska


    In this paper, a semi-Markov model of system operation processes is proposed and its selected parameters are determined. A series-parallel multi-state system is considered, and its reliability and risk characteristics found. Subsequently,a joint model of system operation process and system multi-state reliability and risk is constructed. Moreover, the asymptotic approach to reliability and risk evaluation of a multi-state series-parallel system in its operation process is applied to a port grain transportation system.

  15. Environmental Control and Life Support System Reliability for Long-Duration Missions Beyond Lower Earth Orbit

    Sargusingh, Miriam J.; Nelson, Jason R.


    NASA has highlighted reliability as critical to future human space exploration, particularly in the area of environmental controls and life support systems. The Advanced Exploration Systems (AES) projects have been encouraged to pursue higher reliability components and systems as part of technology development plans. However, no consensus has been reached on what is meant by improving on reliability, or on how to assess reliability within the AES projects. This became apparent when trying to assess reliability as one of several figures of merit for a regenerable water architecture trade study. In the spring of 2013, the AES Water Recovery Project hosted a series of events at Johnson Space Center with the intended goal of establishing a common language and understanding of NASA's reliability goals, and equipping the projects with acceptable means of assessing the respective systems. This campaign included an educational series in which experts from across the agency and academia provided information on terminology, tools, and techniques associated with evaluating and designing for system reliability. The campaign culminated in a workshop that included members of the Environmental Control and Life Support System and AES communities. The goal of this workshop was to develop a consensus on what reliability means to AES and identify methods for assessing low- to mid-technology readiness level technologies for reliability. This paper details the results of that workshop.

  16. A new method for computing the reliability of consecutive k-out-of-n:F systems

    Gökdere Gökhan


    Full Text Available In many physical systems, reliability evaluation, such as ones encountered in telecommunications, the design of integrated circuits, microwave relay stations, oil pipeline systems, vacuum systems in accelerators, computer ring networks, and spacecraft relay stations, have had applied consecutive k-out-of-n system models. These systems are characterized as logical connections among the components of the systems placed in lines or circles. In literature, a great deal of attention has been paid to the study of the reliability evaluation of consecutive k-out-of-n systems. In this paper, we propose a new method to compute the reliability of consecutive k-out-of-n:F systems, with n linearly and circularly arranged components. The proposed method provides a simple way for determining the system failure probability. Also, we write R-Project codes based on our proposed method to compute the reliability of the linear and circular systems which have a great number of components.

  17. Nucleic acid detection system and method for detecting influenza

    Cai, Hong; Song, Jian


    The invention provides a rapid, sensitive and specific nucleic acid detection system which utilizes isothermal nucleic acid amplification in combination with a lateral flow chromatographic device, or DNA dipstick, for DNA-hybridization detection. The system of the invention requires no complex instrumentation or electronic hardware, and provides a low cost nucleic acid detection system suitable for highly sensitive pathogen detection. Hybridization to single-stranded DNA amplification products using the system of the invention provides a sensitive and specific means by which assays can be multiplexed for the detection of multiple target sequences.

  18. Nucleic acid detection system and method for detecting influenza

    Cai, Hong; Song, Jian


    The invention provides a rapid, sensitive and specific nucleic acid detection system which utilizes isothermal nucleic acid amplification in combination with a lateral flow chromatographic device, or DNA dipstick, for DNA-hybridization detection. The system of the invention requires no complex instrumentation or electronic hardware, and provides a low cost nucleic acid detection system suitable for highly sensitive pathogen detection. Hybridization to single-stranded DNA amplification products using the system of the invention provides a sensitive and specific means by which assays can be multiplexed for the detection of multiple target sequences.

  19. Wind energy Computerized Maintenance Management System (CMMS) : data collection recommendations for reliability analysis.

    Peters, Valerie A.; Ogilvie, Alistair; Veers, Paul S.


    This report addresses the general data requirements for reliability analysis of fielded wind turbines and other wind plant equipment. The report provides a list of the data needed to support reliability and availability analysis, and gives specific recommendations for a Computerized Maintenance Management System (CMMS) to support automated analysis. This data collection recommendations report was written by Sandia National Laboratories to address the general data requirements for reliability analysis of fielded wind turbines. This report is intended to help the reader develop a basic understanding of what data are needed from a Computerized Maintenance Management System (CMMS) and other data systems, for reliability analysis. The report provides: (1) a list of the data needed to support reliability and availability analysis; and (2) specific recommendations for a CMMS to support automated analysis. Though written for reliability analysis of wind turbines, much of the information is applicable to a wider variety of equipment and a wider variety of analysis and reporting needs.

  20. Reliability design of mechanical systems a guide for mechanical and civil engineers

    Woo, Seongwoo


    This book describes basic reliability concepts – parametric ALT plan, failure mechanism and design, and reliability testing with acceleration factor and sample size equation. A generalized life-stress failure model with a new effort concept has been derived and recommended to calculate the acceleration factor of the mechanical system. The new sample size equation with the acceleration factor has also been derived to carry out the parametric ALT. This new parametric ALT should help a mechanical/civil engineer to uncover the design parameters affecting reliability during the design process of the mechanical system. Consequently, it should help companies to improve product reliability and avoid recalls due to the product/structure failures in the field. As the improper or missing design parameters in the design phase are experimentally identified by this new reliability design method - parametric ALT, the mechanical/civil engineering system might improve in reliability by the increase in lifetime and the reduc...

  1. Capillary Electrophoresis - Optical Detection Systems

    Sepaniak, M. J.


    Molecular recognition systems are developed via molecular modeling and synthesis to enhance separation performance in capillary electrophoresis and optical detection methods for capillary electrophoresis. The underpinning theme of our work is the rational design and development of molecular recognition systems in chemical separations and analysis. There have been, however, some subtle and exciting shifts in our research paradigm during this period. Specifically, we have moved from mostly separations research to a good balance between separations and spectroscopic detection for separations. This shift is based on our perception that the pressing research challenges and needs in capillary electrophoresis and electrokinetic chromatography relate to the persistent detection and flow rate reproducibility limitations of these techniques (see page 1 of the accompanying Renewal Application for further discussion). In most of our work molecular recognition reagents are employed to provide selectivity and enhance performance. Also, an emerging trend is the use of these reagents with specially-prepared nano-scale materials. Although not part of our DOE BES-supported work, the modeling and synthesis of new receptors has indirectly supported the development of novel microcantilevers-based MEMS for the sensing of vapor and liquid phase analytes. This fortuitous overlap is briefly covered in this report. Several of the more significant publications that have resulted from our work are appended. To facilitate brevity we refer to these publications liberally in this progress report. Reference is also made to very recent work in the Background and Preliminary Studies Section of the Renewal Application.

  2. Compensated intruder-detection systems

    McNeilly, David R.; Miller, William R.


    Intruder-detection systems in which intruder-induced signals are transmitted through a medium also receive spurious signals induced by changes in a climatic condition affecting the medium. To combat this, signals received from the detection medium are converted to a first signal. The system also provides a reference signal proportional to climate-induced changes in the medium. The first signal and the reference signal are combined for generating therefrom an output signal which is insensitive to the climatic changes in the medium. An alarm is energized if the output signal exceeds a preselected value. In one embodiment, an acoustic cable is coupled to a fence to generate a first electrical signal proportional to movements thereof. False alarms resulting from wind-induced movements of the fence (detection medium) are eliminated by providing an anemometer-driven voltage generator to provide a reference voltage proportional to the velocity of wind incident on the fence. An analog divider receives the first electrical signal and the reference signal as its numerator and denominator inputs, respectively, and generates therefrom an output signal which is insensitive to the wind-induced movements in the fence.

  3. Sensitive and reliable detection of grapevine fanleaf virus in a single Xiphinema index nematode vector.

    Demangeat, Gérard; Komar, Véronique; Cornuet, Pascal; Esmenjaud, Daniel; Fuchs, Marc


    Grapevine fanleaf virus (GFLV) is specifically transmitted from plant to plant by the ectoparasitic nematode Xiphinema index. A sensitive and reliable procedure was developed to readily detect GFLV in a single viruliferous X. index, regardless of the nematode origin, i.e. greenhouse rearings or vineyard soils. The assay is based on bead milling to disrupt nematodes extracted from soil samples, solid-phase extraction of total nematode RNAs, and amplification of a 555bp fragment of the coat protein (CP) gene by reverse transcription-polymerase chain reaction with two primers designed from conserved sequences. This procedure is sensitive since the CP gene fragment is amplified from an artificial sample consisting of one viruliferous nematode mixed with 3000 aviruliferous individuals. In addition, StyI RFLP analysis of the CP amplicon enables the GFLV isolate carried by a single viruliferous X. index to be characterized. This GFLV detection assay opens new avenues for epidemiological studies and for molecular investigations on the mechanism of X. index-mediated GFLV transmission.

  4. Strategy for Synthesis of Flexible Heat Exchanger Networks Embedded with System Reliability Analysis

    YI Dake; HAN Zhizhong; WANG Kefeng; YAO Pingjing


    System reliability can produce a strong influence on the performance of the heat exchanger network (HEN).In this paper,an optimization method with system reliability analysis for flexible HEN by genetic/simulated annealing algorithms (GA/SA) is presented.Initial flexible arrangements of HEN is received by pseudo-temperature enthalpy diagram.For determining system reliability of HEN,the connections of heat exchangers(HEXs) and independent subsystems in the HEN are analyzed by the connection sequence matrix(CSM),and the system reliability is measured by the independent subsystem including maximum number of HEXs in the HEN.As for the HEN that did not meet system reliability,HEN decoupling is applied and the independent subsystems in the HEN are changed by removing decoupling HEX,and thus the system reliability is elevated.After that,heat duty redistribution based on the relevant elements of the heat load loops and HEX areas are optimized in GA/SA.Then,the favorable network configuration,which matches both the most economical cost and system reliability criterion,is located.Moreover,particular features belonging to suitable decoupling HEX are extracted from calculations.Corresponding numerical example is presented to verify that the proposed strategy is effective to formulate optimal flexible HEN with system reliability measurement.


    R.K. Agnihotri


    Full Text Available The present paper deals with the reliability analysis of a system of boiler used in garment industry.The system consists of a single unit of boiler which plays an important role in garment industry. Usingregenerative point technique with Markov renewal process various reliability characteristics of interest areobtained.

  6. System reliability with correlated components: Accuracy of the Equivalent Planes method

    Roscoe, K.; Diermanse, F.; Vrouwenvelder, A.C.W.M.


    Computing system reliability when system components are correlated presents a challenge because it usually requires solving multi-fold integrals numerically, which is generally infeasible due to the computational cost. In Dutch flood defense reliability modeling, an efficient method for computing th

  7. Fast and reliable obstacle detection and segmentation for cross-country navigation

    Talukder, A.; Manduchi, R.; Rankin, A.; Matthies, L.


    Obstacle detection is one of the main components of the control system of autonomous vehicles. In the case of indoor/urban navigation, obstacles are typically defined as surface points that are higher than the ground plane. This characterization, however, cannot be used in cross-country and unstructured environments, where the notion of ground plane is often not meaningful.

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



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


    Sun Youchao; Shi Jun


    The reliability assessment of unit-system near two levels is the most important content in the reliability multi-level synthesis of complex systems. Introducing the information theory into system reliability assessment, using the addible characteristic of information quantity and the principle of equivalence of information quantity, an entropy method of data information conversion is presented for the system consisted of identical exponential units. The basic conversion formulae of entropy method of unit test data are derived based on the principle of information quantity equivalence. The general models of entropy method synthesis assessment for system reliability approximate lower limits are established according to the fundamental principle of the unit reliability assessment. The applications of the entropy method are discussed by way of practical examples. Compared with the traditional methods, the entropy method is found to be valid and practicable and the assessment results are very satisfactory.

  10. Reliable fuzzy control with domain guaranteed cost for fuzzy systems with actuator failures

    JIA Xinchun; ZHENG Nanning


    The reliable fuzzy control with guaranteed cost for T-S fuzzy systems with actuator failure is proposed in this paper. The cost function is a quadratic function with failure input. When the initial state of such systems is known, a design method of the reliable fuzzy controller with reliable guaranteed cost is presented, and the formula of the guaranteed cost is established. When the initial state of such systems is unknown but belongs to a known bounded closed domain, a notion of the reliable domain guaranteed cost (RDGC) for such systems is proposed. For two classes of initial state domain, polygon domain and ellipsoid domain, some design methods for reliable fuzzy controllers with the RDGC are provided. The efficiency of our design methods is finally verified by numerical design and simulation on the Rossler chaotic system.

  11. CardioGuard: a brassiere-based reliable ECG monitoring sensor system for supporting daily smartphone healthcare applications.

    Kwon, Sungjun; Kim, Jeehoon; Kang, Seungwoo; Lee, Youngki; Baek, Hyunjae; Park, Kwangsuk


    We propose CardioGuard, a brassiere-based reliable electrocardiogram (ECG) monitoring sensor system, for supporting daily smartphone healthcare applications. It is designed to satisfy two key requirements for user-unobtrusive daily ECG monitoring: reliability of ECG sensing and usability of the sensor. The system is validated through extensive evaluations. The evaluation results showed that the CardioGuard sensor reliably measure the ECG during 12 representative daily activities including diverse movement levels; 89.53% of QRS peaks were detected on average. The questionnaire-based user study with 15 participants showed that the CardioGuard sensor was comfortable and unobtrusive. Additionally, the signal-to-noise ratio test and the washing durability test were conducted to show the high-quality sensing of the proposed sensor and its physical durability in practical use, respectively.

  12. Windfarm Generation Assessment for Reliability Analysis of Power Systems

    Barberis Negra, Nicola; Bak-Jensen, Birgitte; Holmstrøm, O.


    a significant role in this assessment and different models have been created for it, but a representation which includes all of them has not been developed yet. This paper deals with this issue. First, a list of nine influencing Factors is presented and discussed. Secondly, these Factors are included...... in a reliability model and the generation of a windfarm is evaluated by means of sequential Monte Carlo simulation. Results are used to analyse how each mentioned Factor influences the assessment, and why and when they should be included in the model....

  13. Windfarm Generation Assessment for ReliabilityAnalysis of Power Systems

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


    a significant role in this assessment and different models have been created for it, but a representation which includes all of them has not been developed yet. This paper deals with this issue. First, a list of nine influencing Factors is presented and discussed. Secondly, these Factors are included...... in a reliability model and the generation of a windfarm is evaluated by means of sequential Monte Carlo simulation. Results are used to analyse how each mentioned Factor influences the assessment, and why and when they should be included in the model....

  14. Reliability/Cost Evaluation on Power System connected with Wind Power for the Reserve Estimation

    Lee, Go-Eun; Cha, Seung-Tae; Shin, Je-Seok;


    Wind power is ideally a renewable energy with no fuel cost, but has a risk to reduce reliability of the whole system because of uncertainty of the output. If the reserve of the system is increased, the reliability of the system may be improved. However, the cost would be increased. Therefore...... the reserve needs to be estimated considering the trade-off between reliability and economic aspects. This paper suggests a methodology to estimate the appropriate reserve, when wind power is connected to the power system. As a case study, when wind power is connected to power system of Korea, the effects...

  15. Reliability of paste fill system of the Jinchuan No.2 mine


    Because of poor ground conditions, stoping methods of underhand headings with cemented fill were used in the Jinchuan No.2 mine, apaste fill system was set up. In order to evaluate the reliability ofthe new system, investigations and trial running have been done. Morethan 20 items of modification or improvements related to paste preparation subsystem, pump and pipe subsystem, auto-controlling and monitoring subsystem were finished. The reliability of the paste fill system was analyzed by using the theory of large complex system, and it is useful in reliability study on paste fill system.

  16. Reliability Equivalence Factors of a System with 2 Non-identical Mixed Lifetimes and Delayed Time

    Abdelfattah Mustafa


    Full Text Available Problem statement: In reliability theory and operations research, there are many methods and techniques to improve the performance of a system. The aim of this study is to generalize reliability equivalence technique to apply it to a mixed failure lifetimes system f1 (t, f2 (t with delayed time. Approach: We shall improve the system by using some reliability techniques: (i reducing the failure for some lifetimes; (ii add hot duplication components; (iii add cold duplication components; (iv add cold duplication components with imperfect switches. We start by establishing two different types of reliability equivalence factors, the Survival Reliability Equivalence (SRE and Mean Reliability Equivalence (MRE factors. Also, we introduced some numerical results. Results: The system reliability function and mean time to failure will be used as reference of the system performances. For this reason, we obtain the reliability functions and mean time to failures of the original and improved systems using each improving methods. Conclusion: The results can be used to distinguish between the original and improved systems performances and calculate the equivalent between different cases of improving methods.

  17. A support architecture for reliable distributed computing systems

    Dasgupta, Partha; Leblanc, Richard J., Jr.


    The Clouds project is well underway to its goal of building a unified distributed operating system supporting the object model. The operating system design uses the object concept of structuring software at all levels of the system. The basic operating system was developed and work is under progress to build a usable system.

  18. Diffusion-weighted MR imaging in postoperative follow-up: Reliability for detection of recurrent cholesteatoma

    Cimsit, Nuri Cagatay [Marmara University Hospital, Department of Radiology, Istanbul (Turkey); Engin Sitesi Peker Sokak No:1 D:13, 34330 Levent, Istanbul (Turkey)], E-mail:; Cimsit, Canan [Goztepe Education and Research Hospital, Department of Radiology, Istanbul (Turkey); Istanbul Goztepe Egitim ve Arastirma Hastanesi, Radyoloji Klinigi, Goztepe, Istanbul (Turkey)], E-mail:; Baysal, Begumhan [Goztepe Education and Research Hospital, Department of Radiology, Istanbul (Turkey); Istanbul Goztepe Egitim ve Arastirma Hastanesi, Radyoloji Klinigi, Goztepe, Istanbul (Turkey)], E-mail:; Ruhi, Ilteris Cagatay [Goztepe Education and Research Hospital, Department of ENT, Istanbul (Turkey); Istanbul Goztepe Egitim ve Arastirma Hastanesi, KBB Klinigi, Goztepe, Istanbul (Turkey)], E-mail:; Ozbilgen, Suha [Goztepe Education and Research Hospital, Department of ENT, Istanbul (Turkey); Istanbul Goztepe Egitim ve Arastirma Hastanesi, KBB Klinigi, Goztepe, Istanbul (Turkey)], E-mail:; Aksoy, Elif Ayanoglu [Acibadem Bakirkoy Hospital, Department of ENT, Istanbul (Turkey); Acibadem Hastanesi, KBB Boeluemue, Bakirkoey, Istanbul (Turkey)], E-mail:


    Introduction: Cholesteatoma is a progressively growing process that destroy the neighboring bony structures and treatment is surgical removal. Follow-up is important in the postoperative period, since further surgery is necessary if recurrence is present, but not if granulation tissue is detected. This study evaluates if diffusion-weighted MR imaging alone can be a reliable alternative to CT, without use of contrast agent for follow-up of postoperative patients in detecting recurrent cholesteatoma. Materials and methods: 26 consecutive patients with mastoidectomy reporting for routine follow-up CT after mastoidectomy were included in the study, if there was loss of middle ear aeration on CT examination. MR images were evaluated for loss of aeration and signal intensity changes on diffusion-weighted sequences. Surgical results were compared with imaging findings. Results: Interpretation of MR images were parallel with the loss of aeration detected on CT for all 26 patients. Of the 26 patients examined, 14 were not evaluated as recurrent cholesteatoma and verified with surgery (NPV: 100%). Twelve patients were diagnosed as recurrent cholesteatoma and 11 were surgically diagnosed as recurrent cholesteatoma (PPV: 91.7%). Four of these 11 patients had loss of aeration size greater than the high signal intensity area on DWI, which were surgically confirmed as granulation tissue or fibrosis accompanying recurrent cholesteatoma. Conclusion: Diffusion-weighted MR for suspected recurrent cholesteatoma is a valuable tool to cut costs and prevent unnecessary second-look surgeries. It has the potential to become the MR sequence of choice to differentiate recurrent cholesteatoma from other causes of loss of aeration in patients with mastoidectomy.

  19. 75 FR 35689 - System Personnel Training Reliability Standards


    ... system are unique, properties such as the location and capabilities of generator units and capacitor banks, typical transmission line loadings, location and function of special protection systems, if...

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

    Lee, James


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

  1. Impacts of Contingency Reserve on Nodal Price and Nodal Reliability Risk in Deregulated Power Systems

    Zhao, Qian; Wang, Peng; Goel, Lalit


    The deregulation of power systems allows customers to participate in power market operation. In deregulated power systems, nodal price and nodal reliability are adopted to represent locational operation cost and reliability performance. Since contingency reserve (CR) plays an important role...... in reliable operation, the CR commitment should be considered in operational reliability analysis. In this paper, a CR model based on customer reliability requirements has been formulated and integrated into power market settlement. A two-step market clearing process has been proposed to determine generation...... and CR allocation. Customers' nodal unit commitment risk and nodal energy interruption have been evaluated through contingency analysis. Customers' reliability cost including reserve service cost and energy interruption cost have also been evaluated....

  2. Optimal Bi-Objective Redundancy Allocation for Systems Reliability and Risk Management

    Govindan, Kannan; Jafarian, Ahmad; Azbari, Mostafa E.


    In the big data era, systems reliability is critical to effective systems risk management. In this paper, a novel multiobjective approach, with hybridization of a known algorithm called NSGA-II and an adaptive population-based simulated annealing (APBSA) method is developed to solve the systems...... of domination; and 4) data envelopment analysis. The computational studies have shown that the proposed algorithm is an effective approach for systems reliability and risk management....

  3. Protocol and Demonstrations of Probabilistic Reliability Assessment for Structural Health Monitoring Systems (Preprint)


    location. Keywords: Model-assisted POD evaluation, probability of detection (POD), reliability, structural health monitoring 1. Introduction The...damage detection method. An ETrema brand Terfenol-D magnetostrictive actuator was used for band- limited pseudo-random excitation up to 1200 Hz, and

  4. Explosives detection system and method

    Reber, Edward L.; Jewell, James K.; Rohde, Kenneth W.; Seabury, Edward H.; Blackwood, Larry G.; Edwards, Andrew J.; Derr, Kurt W.


    A method of detecting explosives in a vehicle includes providing a first rack on one side of the vehicle, the rack including a neutron generator and a plurality of gamma ray detectors; providing a second rack on another side of the vehicle, the second rack including a neutron generator and a plurality of gamma ray detectors; providing a control system, remote from the first and second racks, coupled to the neutron generators and gamma ray detectors; using the control system, causing the neutron generators to generate neutrons; and performing gamma ray spectroscopy on spectra read by the gamma ray detectors to look for a signature indicative of presence of an explosive. Various apparatus and other methods are also provided.

  5. Features of applying systems approach for evaluating the reliability of cryogenic systems for special purposes

    E. D. Chertov


    Full Text Available Summary. The analysis of cryogenic installations confirms objective regularity of increase in amount of the tasks solved by systems of a special purpose. One of the most important directions of development of a cryogenics is creation of installations for air separation product receipt, namely oxygen and nitrogen. Modern aviation complexes require use of these gases in large numbers as in gaseous, and in the liquid state. The onboard gas systems applied in aircraft of the Russian Federation are subdivided on: oxygen system; air (nitric system; system of neutral gas; fire-proof system. Technological schemes ADI are in many respects determined by pressure of compressed air or, in a general sense, a refrigerating cycle. For the majority ADI a working body of a refrigerating cycle the divided air is, that is technological and refrigerating cycles in installation are integrated. By this principle differentiate installations: low pressure; average and high pressure; with detander; with preliminary chilling. There is also insignificant number of the ADI types in which refrigerating and technological cycles are separated. These are installations with external chilling. For the solution of tasks of control of technical condition of the BRV hardware in real time and estimates of indicators of reliability it is offered to use multi-agent technologies. Multi-agent approach is the most acceptable for creation of SPPR for reliability assessment as allows: to redistribute processing of information on elements of system that leads to increase in overall performance; to solve a problem of accumulating, storage and recycling of knowledge that will allow to increase significantly efficiency of the solution of tasks of an assessment of reliability; to considerably reduce intervention of the person in process of functioning of system that will save time of the person of the making decision (PMD and will not demand from it special skills of work with it.

  6. PV system reliability: lessons learned from a fleet of 333 systems

    Kaushik, A.; Golnas, A.


    The levelized cost of energy (LCOE) from PV systems can be reduced by maximizing the energy production of existing/future PV plants through increased availability. This can be achieved by detailed study of root cause and failure analysis of component failures leading to a systematic progress towards improving the reliability of various sub-systems. SunEdison owns/operates ~500 sites across the world and systematically collects field failure data in addition to power output and weather data. Analysis of this information allows following-up on corrective actions to eliminate/minimize the re-occurrence of failures and leads to continuous improvements. This paper will analyze some of the key findings from the system failures as follows: - Inverter failures not only cause most of the system outages, but also result in substantial energy losses. Component failures in PCBs and inverter software/firmware bugs are the most common root cause of system outages - From a systemic root cause perspective, lack of robust quality systems at multiple levels of the supply chain is quite evident, which points toward the need for collectively inculcating the quality culture at every stage of the supply chain - This paper will try to establish the need for "Continuous Improvement Process" (CIP) where systemic issues are confronted and solutions are internalized in the operating procedures as the only path to improving component reliability - For a given level of reliability, cost associated with servicing the plant becomes critical. This paper highlights the importance of using "cost of ownership" metrics for making procurement decisions

  7. Scaled CMOS Reliability and Considerations for Spacecraft Systems: Bottom-Up and Top-Down Perspective

    White, Mark


    New space missions will increasingly rely on more advanced technologies because of system requirements for higher performance, particularly in instruments and high-speed processing. Component-level reliability challenges with scaled CMOS in spacecraft systems from a bottom-up perspective have been presented. Fundamental Front-end and Back-end processing reliability issues with more aggressively scaled parts have been discussed. Effective thermal management from system-level to the componentlevel (top-down) is a key element in overall design of reliable systems. Thermal management in space systems must consider a wide range of issues, including thermal loading of many different components, and frequent temperature cycling of some systems. Both perspectives (top-down and bottom-up) play a large role in robust, reliable spacecraft system design.

  8. Reliability analysis of the control system of large-scale vertical mixing equipment


    The control system of vertical mixing equipment is a concentrate distributed monitoring system (CDMS).A reliability analysis model was built and its analysis was conducted based on reliability modeling theories such as the graph theory,Markov process,and redundancy theory.Analysis and operational results show that the control system can meet all technical requirements for high energy composite solid propellant manufacturing.The reliability performance of the control system can be considerably improved by adopting a control strategy combined with the hot spared redundancy of the primary system and the cold spared redundancy of the emergent one.The reliability performance of the control system can be also improved by adopting the redundancy strategy or improving the quality of each component and cable of the system.

  9. Scaled CMOS Reliability and Considerations for Spacecraft Systems: Bottom-Up and Top-Down Perspective

    White, Mark


    New space missions will increasingly rely on more advanced technologies because of system requirements for higher performance, particularly in instruments and high-speed processing. Component-level reliability challenges with scaled CMOS in spacecraft systems from a bottom-up perspective have been presented. Fundamental Front-end and Back-end processing reliability issues with more aggressively scaled parts have been discussed. Effective thermal management from system-level to the componentlevel (top-down) is a key element in overall design of reliable systems. Thermal management in space systems must consider a wide range of issues, including thermal loading of many different components, and frequent temperature cycling of some systems. Both perspectives (top-down and bottom-up) play a large role in robust, reliable spacecraft system design.

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

    Kuan-Li Peng


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

  11. Acquisition of reliable vacuum hardware for large accelerator systems

    Welch, K.M.


    Credible and effective communications prove to be the major challenge in the acquisition of reliable vacuum hardware. Technical competence is necessary but not sufficient. The authors must effectively communicate with management, sponsoring agencies, project organizations, service groups, staff and with vendors. Most of Deming`s 14 quality assurance tenants relate to creating an enlightened environment of good communications. All projects progress along six distinct, closely coupled, dynamic phases. All six phases are in a state of perpetual change. These phases and their elements are discussed, with emphasis given to the acquisition phase and its related vocabulary. Large projects require great clarity and rigor as poor communications can be costly. For rigor to be cost effective, it can`t be pedantic. Clarity thrives best in a low-risk, team environment.

  12. Energy Efficiency and Reliability in Wireless Biomedical Implant Systems

    Abouei, Jamshid; Plataniotis, Konstantinos N; Pasupathy, Subbarayan


    The use of wireless implant technology requires correct delivery of the vital physiological signs of the patient along with the energy management in power-constrained devices. Toward these goals, we present an augmentation protocol for the physical layer of the Medical Implant Communications Service (MICS) with focus on the energy efficiency of deployed devices over the MICS frequency band. The present protocol uses the rateless code with the Frequency Shift Keying (FSK) modulation scheme to overcome the reliability and power cost concerns in tiny implantable sensors due to the considerable attenuation of propagated signals across the human body. In addition, the protocol allows a fast start-up time for the transceiver circuitry. The main advantage of using rateless codes is to provide an inherent adaptive duty-cycling for power management, due to the flexibility of the rateless code rate. Analytical results demonstrate that an 80% energy saving is achievable with the proposed protocol when compared to the IE...

  13. Reliability Analysis of Production System of Fully-Mechanized Face Based on Output Statistic

    CAI Qing-xiang; LI Nai-liang


    Production system of fully-mechanized face is a complicated system composed of human, machine and environment, meantime influenced by various random factors. Analyzing the reliability of system needs plentiful data by means of system faults statistic. Based on the viewpoint that shift output of fully-mechanized face is the result of various random factors' synthetical influence, the process of how to analyze its reliability was deduced by using probability theory, symbolic statistics theory and systematic reliability theory combined with the concrete case study in this paper. And it has been proved that this method is feasible and valuable.

  14. Performance Reliability Prediction of Complex System Based on the Condition Monitoring Information

    Hongxing Wang


    Full Text Available Complex system performance reliability prediction is one of the means to understand complex systems reliability level, make maintenance decision, and guarantee the safety of operation. By the use of complex system condition monitoring information and condition monitoring information based on support vector machine, the paper aims to provide an evaluation of the degradation of complex system performance. With degradation assessment results as input variables, the prediction model of reliability is established in Winer random process. Taking the aircraft engine as an example, the effectiveness of the proposed method is verified in the paper.

  15. Reliability of EUCLIDIAN: an autonomous robotic system for image-guided prostate brachytherapy.

    Podder, Tarun K; Buzurovic, Ivan; Huang, Ke; Showalter, Timothy; Dicker, Adam P; Yu, Yan


    Recently, several robotic systems have been developed to perform accurate and consistent image-guided brachytherapy. Before introducing a new device into clinical operations, it is important to assess the reliability and mean time before failure (MTBF) of the system. In this article, the authors present the preclinical evaluation and analysis of the reliability and MTBF of an autonomous robotic system, which is developed for prostate seed implantation. The authors have considered three steps that are important in reliability growth analysis. These steps are: Identification and isolation of failures, classification of failures, and trend analysis. For any one-of-a-kind product, the reliability enhancement is accomplished through test-fix-test. The authors have used failure mode and effect analysis for collection and analysis of reliability data by identifying and categorizing the failure modes. Failures were classified according to severity. Failures that occurred during the operation of this robotic system were considered as nonhomogenous Poisson process. The failure occurrence trend was analyzed using Laplace test. For analyzing and predicting reliability growth, commonly used and widely accepted models, Duane's model and the Army Material Systems Analysis Activity, i.e., Crow's model, were applied. The MTBF was used as an important measure for assessing the system's reliability. During preclinical testing, 3196 seeds (in 53 test cases) were deposited autonomously by the robot and 14 critical failures were encountered. The majority of the failures occurred during the first few cases. The distribution of failures followed Duane's postulation as well as Crow's postulation of reliability growth. The Laplace test index was -3.82 (robotic system. At 95% confidence, the reliability for deposition of 65 seeds was more than 90%. Analyses of failure mode strongly indicated a gradual improvement of reliability of this autonomous robotic system. High MTBF implied that

  16. Constellation Ground Systems Launch Availability Analysis: Enhancing Highly Reliable Launch Systems Design

    Gernand, Jeffrey L.; Gillespie, Amanda M.; Monaghan, Mark W.; Cummings, Nicholas H.


    Success of the Constellation Program's lunar architecture requires successfully launching two vehicles, Ares I/Orion and Ares V/Altair, in a very limited time period. The reliability and maintainability of flight vehicles and ground systems must deliver a high probability of successfully launching the second vehicle in order to avoid wasting the on-orbit asset launched by the first vehicle. The Ground Operations Project determined which ground subsystems had the potential to affect the probability of the second launch and allocated quantitative availability requirements to these subsystems. The Ground Operations Project also developed a methodology to estimate subsystem reliability, availability and maintainability to ensure that ground subsystems complied with allocated launch availability and maintainability requirements. The verification analysis developed quantitative estimates of subsystem availability based on design documentation; testing results, and other information. Where appropriate, actual performance history was used for legacy subsystems or comparative components that will support Constellation. The results of the verification analysis will be used to verify compliance with requirements and to highlight design or performance shortcomings for further decision-making. This case study will discuss the subsystem requirements allocation process, describe the ground systems methodology for completing quantitative reliability, availability and maintainability analysis, and present findings and observation based on analysis leading to the Ground Systems Preliminary Design Review milestone.

  17. Reliability of Cobas Amplicor PCR test in detection of Mycobacterium tuberculosis in respiratory and nonorespiratory specimens

    Lepšanović Zorica


    Full Text Available Background/Aim. Traditional methods for detection of mycobacteria, such as microscopic examination for the presence of acid-fast bacilli and isolation of the organism by culture, have either a low sensitivity and/or specificity, or take weeks before a definite result is available. Molecular methods, especially those based on nucleic acid amplification, are rapid diagnostic methods which combine high sensitivity and high specificity. The aim of this study was to determine the usefulness of the Cobas Amplicor Mycobacterium tuberculosis polymerase chain reaction (CAPCR assay in detecting the tuberculosis cause in respiratory and nonrespiratory specimens (compared to culture. Methods. Specimens were decontaminated by the N-acetyl-L-cystein- NaOH method. A 500 μL aliquot of the processed specimen were used for inoculation of Löwenstein-Jensen (L-J slants, a drop for acid-fast staining, and 100 μL for PCR. The Cobas Amplicor PCR was performed according to the manufacturer's instructions. Results. A total of 110 respiratory and 355 nonrespiratory specimens were investigated. After resolving discrepancies by reviewing medical history, overall sensitivity, specificity, and positive and negative predictive values for CA-PCR assay compared to culture, were 83%, 100%, 100%, and 96.8%, respectively. In comparison, they were 50%, 99.7%, 87.5%, and 98%, respectively, for the nonrespiratory specimens. The inhibition rate was 2.8% for respiratory, and 7.6% for nonrespiratory specimens. Conclusion. CA-PCR is a reliable assay that enables specialists to start treatment promptly on a positive test result. Lower value for specificity in a group of nonrespiratory specimens is a consequence of an extremely small number of mycobacteria in some of them.

  18. OCT4 and SOX2 are reliable markers in detecting stem cells in odontogenic lesions

    Abhishek Banerjee


    Full Text Available Context (Background: Stem cells are a unique subpopulation of cells in the human body with a capacity to initiate differentiation into various cell lines. Tumor stem cells (TSCs are a unique subpopulation of cells that possess the ability to initiate a neoplasm and sustain self-renewal. Epithelial stem cell (ESC markers such as octamer-binding transcription factor 4 (OCT4 and sex-determining region Y (SRY-box 2 (SOX2 are capable of identifying these stem cells expressed during the early stages of tooth development. Aims: To detect the expression of the stem cell markers OCT4 and SOX2 in the normal odontogenic tissues and the odontogenic cysts and tumors. Materials and Methods: Paraffin sections of follicular tissue, radicular cyst, dentigerous cyst, odontogenic keratocyst, ameloblastoma, adenomatoid odontogenic tumor, and ameloblastic carcinoma were obtained from the archives. The sections were subjected to immunohistochemical assay by the use of mouse monoclonal antibodies to OCT4 and SOX2. Statistical Analysis: The results were evaluated by descriptive analysis. Results: The results show the presence of stem cells in the normal and lesional tissues with these stem cell identifying markers. SOX2 was found to be more consistent and reliable in the detection of stem cells. Conclusion: The stem cell expressions are maintained in the tumor transformation of tissue and probably suggest that there is no phenotypic change of stem cells in progression from normal embryonic state to its tumor component. The quantification and localization reveals interesting trends that indicate the probable role of the cells in the pathogenesis of the lesions.

  19. Quality management systems: a reliable proof of conformity.

    Suppo, M


    Doubts have been raised about whether proof of conformity via a certified full quality management system is appropriate for in vitro diagnostic products used for screening blood donations, for example, tests for HIV and hepatitis B and C. This article reviews all the arguments and finds in favour of the proposed system because it involves requirements that extend beyond the normal quality system standard.

  20. Software metrics: Software quality metrics for distributed systems. [reliability engineering

    Post, J. V.


    Software quality metrics was extended to cover distributed computer systems. Emphasis is placed on studying embedded computer systems and on viewing them within a system life cycle. The hierarchy of quality factors, criteria, and metrics was maintained. New software quality factors were added, including survivability, expandability, and evolvability.

  1. Reliability of Cyber Physical Systems with Focus on Building Management Systems

    Lazarova-Molnar, Sanja; Shaker, Hamid Reza; Mohamed, Nader


    Cyber-physical systems are slowly emerging to dominate our world. Cyber-physical systems (CPS) are systems that tightly integrates users, devices and software. Whereas many of these systems are obviously safety-critical systems, some of them become so under special circumstances. This is the case...... with our focus CPS, i.e. building management systems (BMS), which are not always safety critical per se, but under special circumstances they can become such. This certainly depends on the purpose of the building. We can easily imagine BMS of hospital buildings as safety-critical, but also BMS of buildings...... focus on BMS, as our area of interest. Furthermore, we also propose a classification of buildings with respect to the necessity of having their reliability evaluated....

  2. The new features of the ExaMe evaluation system and reliability of its fixed tests.

    Martinková, P; Zvára, K; Zvárová, J; Zvára, K


    The ExaMe system for the evaluation of targeted knowledge has been in development since 1998. The new features of the ExaMe system are introduced in this paper. Especially, the new three-layer architecture is described. Besides the system itself, the properties of fixed tests in the ExaMe system are studied. In special detail, the reliability of the fixed tests is discussed. The theory background is explained and some limitations of the reliability are pointed out. Three characteristics used for estimation of reliability of educational tests are discussed: Cronbach's alpha, standardized item alpha and split half coefficient. The relation between these characteristics and reliability and between characteristics themselves is investigated. In more detail, the properties of Cronbach's alpha, the characteristics mostly used for the estimation of reliability, are discussed. A confidence interval is introduced for the characteristics. Since 2000, the serviceability of the ExaMe evaluation system as the supporting evaluation tool has been repeatedly shown at the courses of Ph.D. studies in biomedical informatics at Charles University in Prague. The ExaMe system also opens new possibilities for self-evaluation and distance learning, especially when connected with electronic books on the Internet. The estimation of reliability of tests contains some limitations. Keeping them in mind, we can still get some information about the quality of certain educational tests. Therefore, the estimation of reliability of the fixed tests is implemented in the ExaMe system.

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

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


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

  4. Reliability optimization of binary state non-repairable systems: A state of the art survey

    Roya Soltani


    Full Text Available IThe purpose of this paper is to discuss the state of the art on models and methods for reliability optimization problems (ROPs including reliability allocation, redundancy allocation and reliability-redundancy allocation. There are literally few surveys for reviewing the literature of the ROPs. Tillman et al. (1980 classified the related papers by system structure, problem type, and solution methods, separately. In another work, Tzafestas (1980 reviewed system reliability optimization models and the optimization techniques. Yearout (1986 reviewed the literature related to standby redundancy. Kuo (2000 studied the system reliability optimization based on system structure and solution methods. Kuo and Prasad (2004 overviewed system reliability optimization methods. Later, Kuo (2007 reviewed recent advances in optimal reliability allocation problems. The present study adds to the previous literature surveys and focuses mainly on papers after year 2000 but with a quick review on the previous works so that the readers become familiar with the existing approaches. This research investigates the literature from system structure, system performance, uncertainty state and solution approach standpoints, simultaneously.

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

    Tang, J


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

  6. Methodologies of the hardware reliability prediction for PSA of digital I and C systems

    Jung, H. S.; Sung, T. Y.; Eom, H. S.; Park, J. K.; Kang, H. G.; Park, J


    Digital I and C systems are being used widely in the Non-safety systems of the NPP and they are expanding their applications to safety critical systems. The regulatory body shifts their policy to risk based and may require Probabilistic Safety Assessment for the digital I and C systems. But there is no established reliability prediction methodology for the digital I and C systems including both software and hardware yet. This survey report includes a lot of reliability prediction methods for electronic systems in view of hardware. Each method has both the strong and the weak points. This report provides the state-of-art of prediction methods and focus on Bellcore method and MIL-HDBK-217F method in deeply. The reliability analysis models are reviewed and discussed to help analysts. Also this report includes state-of-art of software tools that are supporting reliability prediction.

  7. Independent transmission system operators and their role in maintaining reliability in a restructured electric power industry



    This report summarizes the current status of proposals to form Independent System Operators (ISOs) to operate high-voltage transmission systems in the United States and reviews their potential role in maintaining bulk power system reliability. As background information, the likely new industry structure, nature of deregulated markets, and institutional framework for bulk power system reliability are reviewed. The report identifies issues related to the formation of ISOs and their roles in markets and in reliability, and describes potential policy directions for encouraging the formation of effective ISOs and ensuring bulk system reliability. Two appendices are provided, which address: (1) system operation arrangements in other countries, and (2) summaries of regional U.S. ISO proposals.

  8. The application of emulation techniques in the analysis of highly reliable, guidance and control computer systems

    Migneault, Gerard E.


    Emulation techniques can be a solution to a difficulty that arises in the analysis of the reliability of guidance and control computer systems for future commercial aircraft. Described here is the difficulty, the lack of credibility of reliability estimates obtained by analytical modeling techniques. The difficulty is an unavoidable consequence of the following: (1) a reliability requirement so demanding as to make system evaluation by use testing infeasible; (2) a complex system design technique, fault tolerance; (3) system reliability dominated by errors due to flaws in the system definition; and (4) elaborate analytical modeling techniques whose precision outputs are quite sensitive to errors of approximation in their input data. Use of emulation techniques for pseudo-testing systems to evaluate bounds on the parameter values needed for the analytical techniques is then discussed. Finally several examples of the application of emulation techniques are described.

  9. Independent transmission system operators and their role in maintaining reliability in a restructured electric power industry



    This report summarizes the current status of proposals to form Independent System Operators (ISOs) to operate high-voltage transmission systems in the United States and reviews their potential role in maintaining bulk power system reliability. As background information, the likely new industry structure, nature of deregulated markets, and institutional framework for bulk power system reliability are reviewed. The report identifies issues related to the formation of ISOs and their roles in markets and in reliability, and describes potential policy directions for encouraging the formation of effective ISOs and ensuring bulk system reliability. Two appendices are provided, which address: (1) system operation arrangements in other countries, and (2) summaries of regional U.S. ISO proposals.

  10. Derivation of Reliability Index Vector Formula for Series System and Its Application

    KANG Hai-gui; ZHANG Jing; SUN Ying-wei; GUO Wei


    In this study,a reliability index vector formula is proposed for series system with two failure modes in term of the concept of reliability index vector and equivalent failure modes.Firstly,the reliability index vector is introduced to determine the correlation coefficient between two failure modes,and then,the reliability index vector of a series system can be obtained.Several numerical cases and an analysis on offshore platform are performed,and the results show that this scheme provided here has better computational accuracy,and its calculation process is simpler for the series systems reliability calculations compared with the other methods.Also this scheme is more convenient for the engineering applications.

  11. Reliability solutions for a smart digital factory using: (1) RFID based CEP; (2) Image processing based error detection; (3) RFID based HCI

    Badr, Eid


    New technologies have a great influence on the production process in modern factories. Introducing new techniques and methods is crucial to optimize and enhance the working of factories. However, ensuring a reliable and correct integration requires complete evaluation and assessment. In this thesis I utilize RFID systems and image processing to develop and implement real time solutions to enhance and optimize the production and assembly processes. Solutions include: RFID based CEP to detect p...

  12. Reliability of the Advanced Psychodiagnostic Interpretation (API) Scoring System for the Bender Gestalt.

    Aucone, Ernest J.; Raphael, Alan J.; Golden, Charles J.; Espe-Pfeifer, Patricia; Seldon, Jen; Pospisil, Tanya; Dornheim, Liane; Proctor-Weber, Zoe; Calabria, Michael


    Assessed the interrater reliability of the revised Advanced Psychodiagnostic Interpretation (API) (A. Raphael and C. Golden, 1998) scoring system for the Bender Gestalt Test (L. Bender, 1938). Agreement across nine raters exceeded 90% for each of three clinical protocols, and kappa statistics indicated good interrater reliability. (SLD)


    E. Vidya Sagar


    Full Text Available Power reliability and quality are gaining their greater grounds than ever in the power and industrial market of the times. It has become an essential means for the successful dispatch of quality product, operation, services of any industry. The reliability of power distribution network can be greatly enhanced by the automation of its feeder system and other associated parts. Remotely controlled and automated restoration services can avoid the necessity of executing manual switching schedules and are bound to bring about remarkable levels of system reliability and interruption costs. The reliability cost-worth analysis is the excellent tool for evaluation of interruption costs. Reliability cost-worth analysis is very significant in the power system planning, operation, maintenance andexpansion, for it takes into account the customer concerns in the analysis. This paper deals in due detail with the reliability based cost-worth analysis of automated radial distribution network. The direct method of assessing the worth of reliability is to calculate the user costs relevant to interruptions in the power supply. By the application of failure mode effect analysis and cost-worth analysis byusing direct costing method the reliability of radial distribution network can be evaluated. The customer interruption costs’ indices of a radial distribution network calculated using the analytical method applied to an Indian utility network system with 2000KVA& sixteen nodes and the related results of the study are duly discussed in this paper.

  14. Reliability of an occlusal and nonocclusal tooth wear grading system: clinical use versus dental cast assessment

    Wetselaar, P.; Lobbezoo, F.; Koutris, M.; Visscher, C.M.; Naeije, M.


    The reliability of a newly developed tooth wear grading system was assessed both clinically and on dental casts by two observers using 20 participants. The reliability of clinical occlusal/incisal tooth wear grading was fair-to-good to excellent, while that of most of the clinical nonocclusal/noninc

  15. Acquisition and statistical analysis of reliability data for I and C parts in plant protection system

    Lim, T. J.; Byun, S. S.; Han, S. H.; Lee, H. J.; Lim, J. S.; Oh, S. J.; Park, K. Y.; Song, H. S. [Soongsil Univ., Seoul (Korea)


    This project has been performed in order to construct I and C part reliability databases for detailed analysis of plant protection system and to develop a methodology for analysing trip set point drifts. Reliability database for the I and C parts of plant protection system is required to perform the detailed analysis. First, we have developed an electronic part reliability prediction code based on MIL-HDBK-217F. Then we have collected generic reliability data for the I and C parts in plant protection system. Statistical analysis procedure has been developed to process the data. Then the generic reliability database has been constructed. We have also collected plant specific reliability data for the I and C parts in plant protection system for YGN 3,4 and UCN 3,4 units. Plant specific reliability database for I and C parts has been developed by the Bayesian procedure. We have also developed an statistical analysis procedure for set point drift, and performed analysis of drift effects for trip set point. The basis for the detailed analysis can be provided from the reliability database for the PPS I and C parts. The safety of the KSNP and succeeding NPPs can be proved by reducing the uncertainty of PSA. Economic and efficient operation of NPP can be possible by optimizing the test period to reduce utility's burden. 14 refs., 215 figs., 137 tabs. (Author)

  16. Reliability Based Optimal Design of Vertical Breakwaters Modelled as a Series System Failure

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


    Reliability based design of monolithic vertical breakwaters is considered. Probabilistic models of important failure modes such as sliding and rupture failure in the rubble mound and the subsoil are described. Characterisation of the relevant stochastic parameters are presented, and relevant design...... variables are identified and an optimal system reliability formulation is presented. An illustrative example is given....

  17. The Reliability of the Comprehensive System for the Rorschach: A Comment on Meyer (1997).

    Wood, James M.; Nezworski, M. Teresa; Stejskal, William J.


    G. Meyer (1997) attempts to refute the present authors' criticisms of the interrater reliability of the Rorschach Comprehensive System (CS) but misrepresents their position and offers a flawed meta-analysis in support of his own. Rorschach proponents need to undertake high-quality replicated studies of CS reliability and validity. (SLD)

  18. The reliability-quality relationship for quality systems and quality risk management.

    Claycamp, H Gregg; Rahaman, Faiad; Urban, Jason M


    Engineering reliability typically refers to the probability that a system, or any of its components, will perform a required function for a stated period of time and under specified operating conditions. As such, reliability is inextricably linked with time-dependent quality concepts, such as maintaining a state of control and predicting the chances of losses from failures for quality risk management. Two popular current good manufacturing practice (cGMP) and quality risk management tools, failure mode and effects analysis (FMEA) and root cause analysis (RCA) are examples of engineering reliability evaluations that link reliability with quality and risk. Current concepts in pharmaceutical quality and quality management systems call for more predictive systems for maintaining quality; yet, the current pharmaceutical manufacturing literature and guidelines are curiously silent on engineering quality. This commentary discusses the meaning of engineering reliability while linking the concept to quality systems and quality risk management. The essay also discusses the difference between engineering reliability and statistical (assay) reliability. The assurance of quality in a pharmaceutical product is no longer measured only "after the fact" of manufacturing. Rather, concepts of quality systems and quality risk management call for designing quality assurance into all stages of the pharmaceutical product life cycle. Interestingly, most assays for quality are essentially static and inform product quality over the life cycle only by being repeated over time. Engineering process reliability is the fundamental concept that is meant to anticipate quality failures over the life cycle of the product. Reliability is a well-developed theory and practice for other types of manufactured products and manufacturing processes. Thus, it is well known to be an appropriate index of manufactured product quality. This essay discusses the meaning of reliability and its linkages with quality

  19. Algorithm for break even availability allocation in process system modification using deterministic valuation model incorporating reliability

    Shouri, P.V.; Sreejith, P.S. [Division of Mechanical Engineering, School of Engineering, Cochin University of Science and Technology (CUSAT), Cochin 682 022, Kerala (India)


    In the present scenario of energy demand overtaking energy supply, top priority is given for energy conservation programs and policies. As a result, most existing systems are redesigned or modified with a view for improving energy efficiency. Often these modifications can have an impact on process system configuration, thereby affecting process system reliability. The paper presents a model for valuation of process systems incorporating reliability that can be used to determine the change in process system value resulting from system modification. The model also determines the break even system availability and presents an algorithm for allocation of component reliabilities of the modified system based on the break even system availability. The developed equations are applied to a steam power plant to study the effect of various operating parameters on system value. (author)

  20. Intelligent systems for pipeline infrastructure reliability ISPIR progress report 9 : final report

    Gu, G.P.; Doiron, A.; Mohapatra, B.; Papavinasam, S.; Revie, R.W. [Natural Resources Canada, Ottawa, ON (Canada). CANMET Materials Technology Laboratory


    This paper described a multifunctional pipeline monitoring system that used fiber optic sensors and a microbiologically influenced corrosion (MIC) sensor designed by researchers at Natural Resources Canada's CANMET laboratory. The intelligent system for pipeline infrastructure reliability (ISPIR) was developed to monitor pressure and temperature changes; corrosion; cracking and crack propagation; third party intrusion; and pH and dissolved carbon dioxide (CO{sub 2}) concentrations. The ISPIR is also capable of detecting and inspecting leaks, buckling, bending, soil movement, and microbial activity. The fiber optics system measures chemical and microbiological environmental conditions on external pipe surfaces. A structural integrity monitoring software system was used to provide a user-friendly interface for modelling and developing decision-making algorithms. The paper included the results of laboratory tests conducted to evaluate the system's fiber optic pH and CO{sub 2} sensors as well as to assess the accuracy of long gauge monitoring data. Further research is being conducted to develop methods of monitoring disbondment; the development of high axial stresses; and the absence of protective cathodic potential. 11 refs., 9 figs., 1 appendix.

  1. System reliability assessment with an approximate reasoning model

    Eisenhawer, S.W.; Bott, T.F.; Helm, T.M.; Boerigter, S.T.


    The projected service life of weapons in the US nuclear stockpile will exceed the original design life of their critical components. Interim metrics are needed to describe weapon states for use in simulation models of the nuclear weapons complex. The authors present an approach to this problem based upon the theory of approximate reasoning (AR) that allows meaningful assessments to be made in an environment where reliability models are incomplete. AR models are designed to emulate the inference process used by subject matter experts. The emulation is based upon a formal logic structure that relates evidence about components. This evidence is translated using natural language expressions into linguistic variables that describe membership in fuzzy sets. The authors introduce a metric that measures the acceptability of a weapon to nuclear deterrence planners. Implication rule bases are used to draw a series of forward chaining inferences about the acceptability of components, subsystems and individual weapons. They describe each component in the AR model in some detail and illustrate its behavior with a small example. The integration of the acceptability metric into a prototype model to simulate the weapons complex is also described.

  2. Application of reliability worth concepts in power system operational planning

    Mello, J.C.O. [Centro de Pesquisas de Energia Eletrica (CEPEL), Rio de Janeiro, RJ (Brazil); Silva, A.M. Leite da [Pontificia Univ. Catolica do Rio de Janeiro, RJ (Brazil); Pereira, M.V.F. [Power System Research (PSR), Inc., Rio de Janeiro, RJ (Brazil)


    This work describes the application of a new methodology for calculating total system interruption costs in power system operational planning. Some important operational aspects are discussed: chronological load curves, customer damage functions for each consumer class, maintenance scheduling and non-exponential repair times. It is also presented the calculation of the probability distribution of the system interruption cost to improve the decision making process associated with alternative operational strategies. The Brazilian Southeastern system is used to illustrate all previous applications. (author) 24 refs., 8 figs., 4 tabs.

  3. Research on the Reliability Centered Maintenance Plan of a Launching System

    XIE Chao; SUN Ming-fang; DU Jun-min


    Aiming at the shortcomings of the traditional maintenance plan of a launching system, an analysis was made on the development of the reliability centered maintenance methods (RCM) and the basic models for reliability centered maintenance of a launching system are presented in this paper. The common methods for functional impor- tant product determination, failure modes and effect analysis ( FMEA ) and logic decision analysis were illustrated and the basic methods for maintenance interval calculation models were studied based on availability. According to the research, the reliability centered maintenance plan of a certain launching system was given.

  4. Thermal animal detection system (TADS)

    Desholm, M.


    This report presents data from equipment tests and software development for the Thermal Animal Detection System (TADS) development project: 'Development of a method for estimating collision frequency between migrating birds and offshore wind turbines'. The technical tests were performed to investigate the performance of remote controlling, video file compression tool and physical stress of the thermal camera when operating outdoors and under the real time vibration conditions at a 2 MW turbine. Furthermore, experimental tests on birds were performed to describe the decreasing detectability with distance on free flying birds, the performance of the thermal camera during poor visibility, and finally, the performance of the thermal sensor software developed for securing high -quality data. In general, it can be concluded that the thermal camera and its related hardware and software, the TADS, are capable of recording migrating birds approaching the rotating blades of a turbine, even under conditions with poor visibility. If the TADS is used in a vertical viewing scenario it would comply with the requirements for a setup used for estimating the avian collision frequency at offshore wind turbines. (au)

  5. Report on the analysis of field data relating to the reliability of solar hot water systems.

    Menicucci, David F. (Building Specialists, Inc., Albuquerque, NM)


    Utilities are overseeing the installations of thousand of solar hot water (SHW) systems. Utility planners have begun to ask for quantitative measures of the expected lifetimes of these systems so that they can properly forecast their loads. This report, which augments a 2009 reliability analysis effort by Sandia National Laboratories (SNL), addresses this need. Additional reliability data have been collected, added to the existing database, and analyzed. The results are presented. Additionally, formal reliability theory is described, including the bathtub curve, which is the most common model to characterize the lifetime reliability character of systems, and for predicting failures in the field. Reliability theory is used to assess the SNL reliability database. This assessment shows that the database is heavily weighted with data that describe the reliability of SHW systems early in their lives, during the warranty period. But it contains few measured data to describe the ends of SHW systems lives. End-of-life data are the most critical ones to define sufficiently the reliability of SHW systems in order to answer the questions that the utilities pose. Several ideas are presented for collecting the required data, including photometric analysis of aerial photographs of installed collectors, statistical and neural network analysis of energy bills from solar homes, and the development of simple algorithms to allow conventional SHW controllers to announce system failures and record the details of the event, similar to how aircraft black box recorders perform. Some information is also presented about public expectations for the longevity of a SHW system, information that is useful in developing reliability goals.

  6. A stereo vision-based obstacle detection system in vehicles

    Huh, Kunsoo; Park, Jaehak; Hwang, Junyeon; Hong, Daegun


    Obstacle detection is a crucial issue for driver assistance systems as well as for autonomous vehicle guidance function and it has to be performed with high reliability to avoid any potential collision with the front vehicle. The vision-based obstacle detection systems are regarded promising for this purpose because they require little infrastructure on a highway. However, the feasibility of these systems in passenger car requires accurate and robust sensing performance. In this paper, an obstacle detection system using stereo vision sensors is developed. This system utilizes feature matching, epipoplar constraint and feature aggregation in order to robustly detect the initial corresponding pairs. After the initial detection, the system executes the tracking algorithm for the obstacles. The proposed system can detect a front obstacle, a leading vehicle and a vehicle cutting into the lane. Then, the position parameters of the obstacles and leading vehicles can be obtained. The proposed obstacle detection system is implemented on a passenger car and its performance is verified experimentally.

  7. Design and Analysis of a Flexible, Reliable Deep Space Life Support System

    Jones, Harry W.


    This report describes a flexible, reliable, deep space life support system design approach that uses either storage or recycling or both together. The design goal is to provide the needed life support performance with the required ultra reliability for the minimum Equivalent System Mass (ESM). Recycling life support systems used with multiple redundancy can have sufficient reliability for deep space missions but they usually do not save mass compared to mixed storage and recycling systems. The best deep space life support system design uses water recycling with sufficient water storage to prevent loss of crew if recycling fails. Since the amount of water needed for crew survival is a small part of the total water requirement, the required amount of stored water is significantly less than the total to be consumed. Water recycling with water, oxygen, and carbon dioxide removal material storage can achieve the high reliability of full storage systems with only half the mass of full storage and with less mass than the highly redundant recycling systems needed to achieve acceptable reliability. Improved recycling systems with lower mass and higher reliability could perform better than systems using storage.

  8. Reliable systems - Fault tree analysis via Markov reward automata

    Guck, Dennis


    Today’s society is characterised by the ubiquitousness of hardware and software systems on which we rely on day in, day out. They reach from transportation systems like cars, trains and planes over medical devices at a hospital to nuclear power plants. Moreover, we can observe a trend of automation

  9. Reliable systems: fault tree analysis via Markov reward automata

    Guck, Dennis


    Today's society is characterised by the ubiquitousness of hardware and software systems on which we rely on day in, day out. They reach from transportation systems like cars, trains and planes over medical devices at a hospital to nuclear power plants. Moreover, we can observe a trend of automation

  10. Reliable systems: fault tree analysis via Markov reward automata

    Guck, Dennis


    Today's society is characterised by the ubiquitousness of hardware and software systems on which we rely on day in, day out. They reach from transportation systems like cars, trains and planes over medical devices at a hospital to nuclear power plants. Moreover, we can observe a trend of automation

  11. Reliability Analysis of Repairable Systems Using Stochastic Point Processes

    TAN Fu-rong; JIANG Zhi-bin; BAI Tong-shuo


    In order to analyze the failure data from repairable systems, the homogeneous Poisson process(HPP) is usually used. In general, HPP cannot be applied to analyze the entire life cycle of a complex, re-pairable system because the rate of occurrence of failures (ROCOF) of the system changes over time rather thanremains stable. However, from a practical point of view, it is always preferred to apply the simplest methodto address problems and to obtain useful practical results. Therefore, we attempted to use the HPP model toanalyze the failure data from real repairable systems. A graphic method and the Laplace test were also usedin the analysis. Results of numerical applications show that the HPP model may be a useful tool for the entirelife cycle of repairable systems.

  12. First Assessment of Reliability Data for the LHC Accelerator and Detector Cryogenic System Components

    Perinic, G; Alonso-Canella, I; Balle, C; Barth, K; Bel, J F; Benda, V; Bremer, J; Brodzinski, K; Casas-Cubillos, J; Cuccuru, G; Cugnet, M; Delikaris, D; Delruelle, N; Dufay-Chanat, L; Fabre, C; Ferlin, G; Fluder, C; Gavard, E; Girardot, R; Haug, F; Herblin, L; Junker, S; Klabi , T; Knoops, S; Lamboy, J P; Legrand, D; Metselaar, J; Park, A; Perin, A; Pezzetti, M; Penacoba-Fernandez, G; Pirotte, O; Rogez, E; Suraci, A; Stewart, L; Tavian, L J; Tovar-Gonzalez, A; Van Weelderen, R; Vauthier, N; Vullierme, B; Wagner, U


    The Large Hadron Collider (LHC) cryogenic system comprises eight independent refrigeration and distribution systems that supply the eight 3.3 km long accelerator sectors with cryogenic refrigeration power as well as four refrigeration systems for the needs of the detectors ATLAS and CMS. In order to ensure the highest possible reliability of the installations, it is important to apply a reliability centred approach for the maintenance. Even though large scale cryogenic refrigeration exists since the mid 20th century, very little third party reliability data is available today. CERN has started to collect data with its computer aided maintenance management system (CAMMS) in 2009, when the accelerator has gone into normal operation. This paper presents the reliability observations from the operation and the maintenance side, as well as statistical data collected by the means of the CAMMS system.

  13. Analysis and Application of Mechanical System Reliability Model Based on Copula Function

    An Hai


    Full Text Available There is complicated correlations in mechanical system. By using the advantages of copula function to solve the related issues, this paper proposes the mechanical system reliability model based on copula function. And makes a detailed research for the serial and parallel mechanical system model and gets their reliability function respectively. Finally, the application research is carried out for serial mechanical system reliability model to prove its validity by example. Using Copula theory to make mechanical system reliability modeling and its expectation, studying the distribution of the random variables (marginal distribution of the mechanical product’ life and associated structure of variables separately, can reduce the difficulty of multivariate probabilistic modeling and analysis to make the modeling and analysis process more clearly.

  14. Methodological Approach for Performing Human Reliability and Error Analysis in Railway Transportation System

    Fabio De Felice


    Full Text Available Today, billions of dollars are being spent annually world wide to develop, manufacture, and operate transportation system such trains, ships, aircraft, and motor vehicles. Around 70 to 90 percent oftransportation crashes are, directly or indirectly, the result of human error. In fact, with the development of technology, system reliability has increased dramatically during the past decades, while human reliability has remained unchanged over the same period. Accordingly, human error is now considered as the most significant source of accidents or incidents in safety-critical systems. The aim of the paper is the proposal of a methodological approach to improve the transportation system reliability and in particular railway transportation system. The methodology presented is based on Failure Modes, Effects and Criticality Analysis (FMECA and Human Reliability Analysis (HRA.

  15. Evaluation of nodal reliability risk in a deregulated power system with photovoltaic power penetration

    Zhao, Qian; Wang, Peng; Goel, Lalit


    and customer reliability requirements are correlated with energy and reserve prices. Therefore a new method should be developed to evaluate the impacts of PV power on customer reliability and system reserve deployment in the new environment. In this study, a method based on the pseudo-sequential Monte Carlo......Owing to the intermittent characteristic of solar radiation, power system reliability may be affected with high photovoltaic (PV) power penetration. To reduce large variation of PV power, additional system balancing reserve would be needed. In deregulated power systems, deployment of reserves...... simulation technique has been proposed to evaluate the reserve deployment and customers' nodal reliability with high PV power penetration. The proposed method can effectively model the chronological aspects and stochastic characteristics of PV power and system operation with high computation efficiency...

  16. Reliability Allocation of Underwater Experiment System Based on Particle Swarm Optimization

    Lu Xiong


    Full Text Available The problem of system reliability allocation is often solved by direct search method. The shortage, which affects the application of this method, is the large calculation amount of complex system architecture. Particle Swarm Optimization (PSO is a popular and bionic algorithm based on the social behavior associated with bird flocking for optimization problems. The particle swarm optimization, which attracted the interest of researchers. In this paper, a kind of PSO algorithm is proposed to solve underwater experimental system reliability problems. In addition, the reliability of the system model is established as well, the model is numerically simulated by PSO algorithm and examples are provided. The results show that compared to other algorithms, PSO has a better adaptability and can solve the optimal solution more stably without the precocious weakness, which is more suitable for reliability optimization of a system underwater with a more complex structure.

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

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


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

  18. The Reliability Design and Availability Analysis of a Distributed Storage System

    YANG Xiaohui; DU Ruizhong; TIAN Junfeng


    Current distributed parallel file systems and database systems can not satisfy the demands of data-intensive applications, such as storage capacity, access performance, reliability, scalability, and so on. Cluster-based storage systems have some shortcomings, too. To solve this kind of problems, a novel PC storage cluster solution is proposed, a distributed storage system based on 3-tiered agent architecture is designed, the system reliability model based on the master-slave backup mode is built, and the system availability is analyzed with the Markov model. According to the system availability formula and the values of the system parameters, the novel system can provide higher reliability and availability to satisfy users' requirements.

  19. Fisher Pierce products for improving distribution system reliability



    The challenges facing the electric power utility today in the 1990s has changed significantly from those of even 10 years ago. The proliferation of automation and the personnel computer have heightened the requirements and demands put on the electric distribution system. Today`s customers, fighting to compete in a world market, demand quality, uninterrupted power service. Privatization and the concept of unregulated competition require utilities to streamline to minimize system support costs and optimize power delivery efficiency. Fisher Pierce, serving the electric utility industry for over 50 years, offers a line of products to assist utilities in meeting these challenges. The Fisher Pierce Family of products provide tools for the electric utility to exceed customer service demands. A full line of fault indicating devices are offered to expedite system power restoration both locally and in conjunction with SCADA systems. Fisher Pierce is the largest supplier of roadway lighting controls, manufacturing on a 6 million dollar automated line assuring the highest quality in the world. The distribution system capacitor control line offers intelligent local or radio linked switching control to maintain system voltage and Var levels for quality and cost efficient power delivery under varying customer loads. Additional products, designed to authenticate revenue metering calibration and verify on sight metering service wiring, help optimize the profitability of the utility assuring continuous system service improvements for their customers.

  20. Reliability of Structural Systems with regard to Permanent Displacements

    Sørensen, John Dalsgaard; Thoft-Christensen, Palle


    methods/experience related to permanent deformations are described in Grinda et al. [1] and Papadrakakis & Loukakis [2]. For general dynamic systems modelled by one-degree-of-freedom (and two-degrees-of freedom) systems a number of methods exist, see e.g. Nielsen et al. [3] and Toro & Cornell [4]. However...... approach - a differential equation approach - a superposition approach - the simple method These three approaches are described in Sørensen & Thoft-Christensen [5], Sørensen et al. [6] and Sørensen & Thoft-Christensen [7]. It is assumed that the structural system can be modelled by a multi-linear elastic...

  1. Development of a Wearable-Sensor-Based Fall Detection System

    Falin Wu


    Full Text Available Fall detection is a major challenge in the public healthcare domain, especially for the elderly as the decline of their physical fitness, and timely and reliable surveillance is necessary to mitigate the negative effects of falls. This paper develops a novel fall detection system based on a wearable device. The system monitors the movements of human body, recognizes a fall from normal daily activities by an effective quaternion algorithm, and automatically sends request for help to the caregivers with the patient’s location.

  2. Development of a Wearable-Sensor-Based Fall Detection System

    Zhao, Hengyang; Zhao, Yan; Zhong, Haibo


    Fall detection is a major challenge in the public healthcare domain, especially for the elderly as the decline of their physical fitness, and timely and reliable surveillance is necessary to mitigate the negative effects of falls. This paper develops a novel fall detection system based on a wearable device. The system monitors the movements of human body, recognizes a fall from normal daily activities by an effective quaternion algorithm, and automatically sends request for help to the caregivers with the patient's location. PMID:25784933

  3. Energy-Efficient Reliability-Aware Scheduling Algorithm on Heterogeneous Systems

    Xiaoyong Tang


    Full Text Available The amount of energy needed to operate high-performance computing systems increases regularly since some years at a high pace, and the energy consumption has attracted a great deal of attention. Moreover, high energy consumption inevitably contains failures and reduces system reliability. However, there has been considerably less work of simultaneous management of system performance, reliability, and energy consumption on heterogeneous systems. In this paper, we first build the precedence-constrained parallel applications and energy consumption model. Then, we deduce the relation between reliability and processor frequencies and get their parameters approximation value by least squares curve fitting method. Thirdly, we establish a task execution reliability model and formulate this reliability and energy aware scheduling problem as a linear programming. Lastly, we propose a heuristic Reliability-Energy Aware Scheduling (REAS algorithm to solve this problem, which can get good tradeoff among system performance, reliability, and energy consumption with lower complexity. Our extensive simulation performance evaluation study clearly demonstrates the tradeoff performance of our proposed heuristic algorithm.

  4. Development of a Functional Platform for System Reliability Monitoring of Nuclear Power Plants

    Yang, Ming; Zhang, Zhijian; Yoshikawa, Hidekazu [Harbin Engineering University, Harbin (China)


    This paper presents MFM builder, a platform based on Multilevel Flow Modeling (MFM), which provides a graphical interface for modeling functions of complex artificial systems such as nuclear power plant with emphasizing the designed purposes of systems. Several algorithms based on MFM have been developed for dynamic system reliability analysis, fault diagnosis and quantitative software reliability analysis. A Reliability Monitoring System (RMS) of PWR nuclear power plant was developed by integrating above algorithms. Experiments by connecting RMS with a full scale PWR simulator showed that it took 16 seconds for RMS calculating the reliability changes over time of safety-related systems according to given system configurations in the 31 days by one computer run. The proposed reliability monitoring system can be used not only offline as a reliability analysis tool to assist the plant maintenance staffs in maintenance plan making, but also online as a operator support system to assist the operators in Main Control Room (MCR) in their various tasks such as configuration management, fault diagnosis and operational decision making.

  5. Reliability estimation for multiunit nuclear and fossil-fired industrial energy systems

    Sullivan, W. G.; Wilson, J. V.; Klepper, O. H.


    As petroleum-based fuels grow increasingly scarce and costly, nuclear energy may become an important alternative source of industrial energy. Initial applications would most likely include a mix of fossil-fired and nuclear sources of process energy. A means for determining the overall reliability of these mixed systems is a fundamental aspect of demonstrating their feasibility to potential industrial users. Reliability data from nuclear and fossil-fired plants are presented, and several methods of applying these data for calculating the reliability of reasonably complex industrial energy supply systems are given. Reliability estimates made under a number of simplifying assumptions indicate that multiple nuclear units or a combination of nuclear and fossil-fired plants could provide adequate reliability to meet industrial requirements for continuity of service.

  6. A reliable solar-heating system--Huntsville, Alabama


    Final report on solar-heating demonstration project in Huntsville, Alabama, is rich in technical data, planning considerations, test and maintenance data, and other information. It can be useful reference for those planning similar systems.

  7. Cryogenics system: strategy to achieve nominal performance and reliable operation

    Bremer, J; Casas, J; Claudet, S; Delikaris, D; Delruelle, N; Ferlin, G; Fluder, C; Perin, A; Perinic, G; Pezzetti, M; Pirotte, O; Tavian, L; Wagner, U


    During the LHC operation in 2010 and 2011, the cryogenic system has achieved an availability level fulfilling the overall requirement. To reach this level, the cryogenic system has profited like many other beam-dependent systems from the reduced beam parameters. Therefore, impacts of some failures occurred during the LHC operation were mitigated by using the overcapacity margin, the existing built-in redundancy in between adjacent sector cryogenic plants and the "cannibalization" of spares on two idle cryogenic plants. These two first years of operation were also crucial to identify the weaknesses of the present cryogenic maintenance plan and new issues like SEUs. After the LS1, nominal beam parameters are expected and the mitigated measures will be less effective or not applicable at all. Consequently, a consolidation plan to improve the MTBF and the MTTR of the LHC cryogenic system is under definition. Concerning shutdown periods, the present cryogenic sectorization imposes some restrictions in the type of ...

  8. Reliability of structural systems subjected to extreme forcing events

    Joo, Han-Kyul; Sapsis, Themistoklis P


    We characterize the complex, heavy-tailed probability distribution functions (pdf) describing the response and its local extrema for structural systems subjected to random forcing that includes extreme events. Our approach is based on the recent probabilistic decomposition-synthesis technique in, where we decouple rare events regimes from the background fluctuations. The result of the analysis has the form of a semi-analytical approximation formula for the pdf of the response (displacement, velocity, and acceleration) and the pdf of the local extrema. For special limiting cases (lightly damped or heavily damped systems) our analysis provides fully analytical approximations. We also demonstrate how the method can be applied to high dimensional structural systems through a two-degrees-of-freedom structural system undergoing rare events due to intermittent forcing. The derived formulas can be evaluated with very small computational cost and are shown to accurately capture the complicated heavy-tailed and asymmet...

  9. Reliability review of the remote tool delivery system locomotor

    Chesser, J.B.


    The locomotor being built by RedZone Robotics is designed to serve as a remote tool delivery (RID) system for waste retrieval, tank cleaning, viewing, and inspection inside the high-level waste tanks 8D-1 and 8D-2 at West Valley Nuclear Services (WVNS). The RTD systm is to be deployed through a tank riser. The locomotor portion of the RTD system is designed to be inserted into the tank and is to be capable of moving around the tank by supporting itself and moving on the tank internal structural columns. The locomotor will serve as a mounting platform for a dexterous manipulator arm. The complete RTD system consists of the locomotor, dexterous manipulator arm, cameras, lights, cables, hoses, cable/hose management system, power supply, and operator control station.

  10. a Uav-Based ROE Deer Fawn Detection System

    Israel, M.


    This paper presents a UAV based remote sensing system for the detection of fawns in the meadows. There is a high demand because during pasture mowing many wild animals, especially roe deer fawns are killed by mowing machines. The system was tested in several real situations especially with differing weather and iluminating conditions. Its primary sensor is a lightweight thermal infrared camera. The images are captured onboard of the flight system and also transmitted as analog video stream to the ground station, where the user can follow the camera live stream on a monitor for manual animal detection. Beside a high detection rate a fast workflow is another very important objective for this application. Therefore a waypoint planning software was developed that accelerates the workflow. At adequate illuminating and weather conditions the presented UAV-based fawn detection via thermal imaging is a comfortable, fast and reliable method.

  11. Autonomous system for pathogen detection and identification

    Belgrader, P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Benett, W. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Bergman, W. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Langlois, R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Mariella, R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Milanovich, F. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Miles, R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Venkateswaran, K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Long, G. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Nelson, W. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)


    This purpose of this project is to build a prototype instrument that will, running unattended, detect, identify, and quantify BW agents. In order to accomplish this, we have chosen to start with the world' s leading, proven, assays for pathogens: surface-molecular recognition assays, such as antibody-based assays, implemented on a high-performance, identification (ID)-capable flow cytometer, and the polymerase chain reaction (PCR) for nucleic-acid based assays. With these assays, we must integrate the capability to: l collect samples from aerosols, water, or surfaces; l perform sample preparation prior to the assays; l incubate the prepared samples, if necessary, for a period of time; l transport the prepared, incubated samples to the assays; l perform the assays; l interpret and report the results of the assays. Issues such as reliability, sensitivity and accuracy, quantity of consumables, maintenance schedule, etc. must be addressed satisfactorily to the end user. The highest possible sensitivity and specificity of the assay must be combined with no false alarms. Today, we have assays that can, in under 30 minutes, detect and identify simulants for BW agents at concentrations of a few hundred colony-forming units per ml of solution. If the bio-aerosol sampler of this system collects 1000 Ymin and concentrates the respirable particles into 1 ml of solution with 70% processing efficiency over a period of 5 minutes, then this translates to a detection/ID capability of under 0.1 agent-containing particle/liter of air.

  12. Problems Related to Use of Some Terms in System Reliability Analysis

    Nadezda Hanusova


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

  13. Distributed Impact Detection System Project

    National Aeronautics and Space Administration — Automated impact detection and characterization on manned spacecraft has been an elusive goal due to the transitory nature of the detectable high-frequency signals....

  14. Reliability and validity of an indicator system for assessing the quality of ophthalmic nursing

    Jing-Hua Shi


    Conclusions: The indicator system for evaluating the quality of ophthalmic nursing has favorable reliability and validity, which means that it is a suitable clinical tool for assessing the quality of ophthalmic nursing.


    Ahmad A. Moreb


    Reliability allocation problem is commonly treated using a closed-form expression relating the cost to reliability. A recent approach has introduced the use of discrete integer technique for un-repairable systems. This research addresses the allocation problem for repairable systems. It presents an integer formulation for finding the optimum selection of components based on the integer values of their Mean Time to Failure (MTTF) and Mean Time to Repair (MTTR). The objective is to minimize the total cost under a system reliability constraint, in addition to other physical constraints. Although, a closed-form expression relating the cost to reliability may not be a linear; however, in this research, the objective function will always be linear regardless of the shape of the equivalent continuous closed-form function. An example is solved using the proposed method and compared with the solution of the continuous closed-form version. The formulation for all possible system configurations, components and subsystems are also considered.

  16. Stochastic Reliability Measurement and Design Optimization of an Inventory Management System

    Abdulaziz T. Almaktoom


    Full Text Available Inventory management systems and dynamic reliability measures and controls remain challenging at every stage, especially when time variances and operating conditions are considered. An inventory management system must maintain its adeptness over time while coping with the uncertainty of inventory flow. Unexpected delays during inventory movement can harm the reliability and robustness of the entire system. This paper introduces a method of quantifying the reliability of an inventory management system. Also, a novel, reliability-based robust design optimization model has been developed to optimally allocate and schedule time while considering uncertainty associated with inventory movement. The processes involved include purchasing, shipping, receiving, tracking, warehousing, storage, and turnover. A case study of a furniture company in Saudi Arabia is presented to demonstrate the efficacy of the model.

  17. Extending attributes page: a scheme for enhancing the reliability of storage system metadata*

    Juan WANG; Dan FENG; Fang WANG; Cheng-tao LU


    In an object-based storage system, a novel scheme named EAP (extending attributes page) is presented to enhance the metadata reliability of the system by adding the user object file information attributes page for each user object and storing the file-related attributes of each user object in object-based storage devices. The EAP scheme requires no additional hardware equipments compared to a general method which uses backup metadata servers to improve the metadata reliability. Leveraging a Markov chain, this paper compares the metadata reliability of the system using the EAP scheme with that using only metadata servers to offer the file metadata service. Our results demonstrate that the EAP scheme can dramatically enhance the reliability of storage system metadata.


    PORTELLA, Cristiane M. de M. A; CAVALCANTI, Eduardo H. S; RESENDE, Vera L. D; SILVA, Fernanda dos S; SIMÕES, Maria Gabriela P. de A


    ... with metrological reliability. In this context, the implementation of quality management system based on standard ISO / IEC 17025 is indispensable, as in the case of providers laboratories of specialized technical services...

  19. Design for Reliability of Power Electronics for Grid-Connected Photovoltaic Systems

    Yang, Yongheng; Sangwongwanich, Ariya; Blaabjerg, Frede


    Power electronics is the enabling technology for optimizing energy harvesting from renewable systems like Photovoltaic (PV) and wind power systems, and also for interfacing grid-friendly energy systems. Advancements in the power semiconductor technology (e.g., wide band-gap devices) have pushed...... the conversion efficiency of power electronics to above 98%, where however te reliability of power electronics is becoming of high concern. Therefore, it is important to design for reliable power electronic systems to lower the risks of many failures during operation; otherwise will increase the cost...... as well as to design for high reliability at an early stage. Knowhow of the loading in power electronics in harsh operating environments (e.g., fluctuating ambient temperature and solar irradiance) is important for life-time prediction, as the prerequisite of Deign for Reliability (DfR). Hence...

  20. 75 FR 57764 - Mandatory Reliability Standards for the Bulk Power System; Supplemental Notice of Technical...


    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Mandatory Reliability Standards for the Bulk Power System; Supplemental Notice of Technical Conference September 14, 2010. On August 19, 2010 the Federal Energy...