WorldWideScience

Sample records for fault tolerant systems

  1. Fault Tolerant Control Systems

    DEFF Research Database (Denmark)

    Bøgh, S.A.

    requirements for a dedicated software environment for fault tolerant control systems design. The second detailed study addressed the detection of a fault event and determination of the failed component. A variety of algorithms were compared, based on two fault scenarios in the speed governor actuator setup......This thesis considered the development of fault tolerant control systems. The focus was on the category of automated processes that do not necessarily comprise a high number of identical sensors and actuators to maintain safe operation, but still have a potential for improving immunity to component...... failures. It is often feasible to increase availability for these control loops by designing the control system to perform on-line detection and reconfiguration in case of faults before the safety system makes a close-down of the process. A general development methodology is given in the thesis...

  2. Fault tolerant control for switched linear systems

    CERN Document Server

    Du, Dongsheng; Shi, Peng

    2015-01-01

    This book presents up-to-date research and novel methodologies on fault diagnosis and fault tolerant control for switched linear systems. It provides a unified yet neat framework of filtering, fault detection, fault diagnosis and fault tolerant control of switched systems. It can therefore serve as a useful textbook for senior and/or graduate students who are interested in knowing the state-of-the-art of filtering, fault detection, fault diagnosis and fault tolerant control areas, as well as recent advances in switched linear systems.  

  3. Soft Computing Approaches To Fault Tolerant Systems

    Directory of Open Access Journals (Sweden)

    Neeraj Prakash Srivastava

    2014-05-01

    Full Text Available We present in this paper as an introduction to soft computing techniques for fault tolerant systems and the terminology with different ways of achieving fault tolerance. The paper focuses on the problem of fault tolerance using soft computing techniques. The fundamentals of soft computing approaches and its type with introduction of fault tolerance are discussed. The main objective is to show how to implement soft computing approaches for fault detection, isolation and identification. The paper contains details about soft computing application with an application of wireless sensor network as fault tolerant system.

  4. Synthesis of Fault-Tolerant Embedded Systems

    DEFF Research Database (Denmark)

    Eles, Petru; Izosimov, Viacheslav; Pop, Paul;

    2008-01-01

    This work addresses the issue of design optimization for fault- tolerant hard real-time systems. In particular, our focus is on the handling of transient faults using both checkpointing with rollback recovery and active replication. Fault tolerant schedules are generated based on a conditional...... process graph representation. The formulated system synthesis approaches decide the assignment of fault-tolerance policies to processes, the optimal placement of checkpoints and the mapping of processes to processors, such that multiple transient faults are tolerated, transparency requirements...

  5. Reconfigurable fault tolerant avionics system

    Science.gov (United States)

    Ibrahim, M. M.; Asami, K.; Cho, Mengu

    This paper presents the design of a reconfigurable avionics system based on modern Static Random Access Memory (SRAM)-based Field Programmable Gate Array (FPGA) to be used in future generations of nano satellites. A major concern in satellite systems and especially nano satellites is to build robust systems with low-power consumption profiles. The system is designed to be flexible by providing the capability of reconfiguring itself based on its orbital position. As Single Event Upsets (SEU) do not have the same severity and intensity in all orbital locations, having the maximum at the South Atlantic Anomaly (SAA) and the polar cusps, the system does not have to be fully protected all the time in its orbit. An acceptable level of protection against high-energy cosmic rays and charged particles roaming in space is provided within the majority of the orbit through software fault tolerance. Check pointing and roll back, besides control flow assertions, is used for that level of protection. In the minority part of the orbit where severe SEUs are expected to exist, a reconfiguration for the system FPGA is initiated where the processor systems are triplicated and protection through Triple Modular Redundancy (TMR) with feedback is provided. This technique of reconfiguring the system as per the level of the threat expected from SEU-induced faults helps in reducing the average dynamic power consumption of the system to one-third of its maximum. This technique can be viewed as a smart protection through system reconfiguration. The system is built on the commercial version of the (XC5VLX50) Xilinx Virtex5 FPGA on bulk silicon with 324 IO. Simulations of orbit SEU rates were carried out using the SPENVIS web-based software package.

  6. Software fault tolerance in computer operating systems

    Science.gov (United States)

    Iyer, Ravishankar K.; Lee, Inhwan

    1994-01-01

    This chapter provides data and analysis of the dependability and fault tolerance for three operating systems: the Tandem/GUARDIAN fault-tolerant system, the VAX/VMS distributed system, and the IBM/MVS system. Based on measurements from these systems, basic software error characteristics are investigated. Fault tolerance in operating systems resulting from the use of process pairs and recovery routines is evaluated. Two levels of models are developed to analyze error and recovery processes inside an operating system and interactions among multiple instances of an operating system running in a distributed environment. The measurements show that the use of process pairs in Tandem systems, which was originally intended for tolerating hardware faults, allows the system to tolerate about 70% of defects in system software that result in processor failures. The loose coupling between processors which results in the backup execution (the processor state and the sequence of events occurring) being different from the original execution is a major reason for the measured software fault tolerance. The IBM/MVS system fault tolerance almost doubles when recovery routines are provided, in comparison to the case in which no recovery routines are available. However, even when recovery routines are provided, there is almost a 50% chance of system failure when critical system jobs are involved.

  7. Energy-efficient fault-tolerant systems

    CERN Document Server

    Mathew, Jimson; Pradhan, Dhiraj K

    2013-01-01

    This book describes the state-of-the-art in energy efficient, fault-tolerant embedded systems. It covers the entire product lifecycle of electronic systems design, analysis and testing and includes discussion of both circuit and system-level approaches. Readers will be enabled to meet the conflicting design objectives of energy efficiency and fault-tolerance for reliability, given the up-to-date techniques presented.

  8. Fault tolerant architecture for artificial olfactory system

    International Nuclear Information System (INIS)

    In this paper, to cover and mask the faults that occur in the sensing unit of an artificial olfactory system, a novel architecture is offered. The proposed architecture is able to tolerate failures in the sensors of the array and the faults that occur are masked. The proposed architecture for extracting the correct results from the output of the sensors can provide the quality of service for generated data from the sensor array. The results of various evaluations and analysis proved that the proposed architecture has acceptable performance in comparison with the classic form of the sensor array in gas identification. According to the results, achieving a high odor discrimination based on the suggested architecture is possible. (paper)

  9. Fault tolerant architecture for artificial olfactory system

    Science.gov (United States)

    Lotfivand, Nasser; Nizar Hamidon, Mohd; Abdolzadeh, Vida

    2015-05-01

    In this paper, to cover and mask the faults that occur in the sensing unit of an artificial olfactory system, a novel architecture is offered. The proposed architecture is able to tolerate failures in the sensors of the array and the faults that occur are masked. The proposed architecture for extracting the correct results from the output of the sensors can provide the quality of service for generated data from the sensor array. The results of various evaluations and analysis proved that the proposed architecture has acceptable performance in comparison with the classic form of the sensor array in gas identification. According to the results, achieving a high odor discrimination based on the suggested architecture is possible.

  10. A Fault-tolerant Development Methodology for Industrial Control Systems

    DEFF Research Database (Denmark)

    Izadi-Zamanabadi, Roozbeh; Thybo, C.

    2004-01-01

    and logically sound manner. This paper presents the employe fault-tolerant development methodology and highlights steps, which have been essential for achieving complete and consistent monitoring capabilities. Fault diagnosis for a commercial refrigeration system is treated as a case-study.......Developing advanced detection schemes is not the lone factor for obtaining a successful fault diagnosis performance. Acquiring significant achievements in applying Fault-tolerance in industrial development requires that fault diagnosis and recovery schemes are developed in a consistent...

  11. Method and system for environmentally adaptive fault tolerant computing

    Science.gov (United States)

    Copenhaver, Jason L. (Inventor); Jeremy, Ramos (Inventor); Wolfe, Jeffrey M. (Inventor); Brenner, Dean (Inventor)

    2010-01-01

    A method and system for adapting fault tolerant computing. The method includes the steps of measuring an environmental condition representative of an environment. An on-board processing system's sensitivity to the measured environmental condition is measured. It is determined whether to reconfigure a fault tolerance of the on-board processing system based in part on the measured environmental condition. The fault tolerance of the on-board processing system may be reconfigured based in part on the measured environmental condition.

  12. Fault tolerant aggregation for power system services

    DEFF Research Database (Denmark)

    Kosek, Anna Magdalena; Gehrke, Oliver; Kullmann, Daniel

    2013-01-01

    Exploiting the flexibility in distributed energy resources (DER) is seen as an important contribution to allow high penetrations of renewable generation in electrical power systems. However, the present control infrastructure in power systems is not well suited for the integration of a very large...... number of small units. A common approach is to aggregate a portfolio of such units together and expose them to the power system as a single large virtual unit. In order to realize the vision of a Smart Grid, concepts for flexible, resilient and reliable aggregation infrastructures are required....... This paper presents such a concept while focusing on the aspect of resilience and fault tolerance. The proposed concept makes use of a multi-level election algorithm to transparently manage the addition, removal, failure and reorganization of units. It has been implemented and tested as a proof...

  13. Fault-tolerant Actuator System for Electrical Steering of Vehicles

    DEFF Research Database (Denmark)

    Sørensen, Jesper Sandberg; Blanke, Mogens

    2006-01-01

    Being critical to the safety of vehicles, the steering system is required to maintain the vehicles ability to steer until it is brought to halt, should a fault occur. With electrical steering becoming a cost-effective candidate for electrical powered vehicles, a fault-tolerant architecture...... is needed that meets this requirement. This paper studies the fault-tolerance properties of an electrical steering system. It presents a fault-tolerant architecture where a dedicated AC motor design used in conjunction with cheap voltage measurements can ensure detection of all relevant faults...

  14. Fault detection and fault-tolerant control for nonlinear systems

    CERN Document Server

    Li, Linlin

    2016-01-01

    Linlin Li addresses the analysis and design issues of observer-based FD and FTC for nonlinear systems. The author analyses the existence conditions for the nonlinear observer-based FD systems to gain a deeper insight into the construction of FD systems. Aided by the T-S fuzzy technique, she recommends different design schemes, among them the L_inf/L_2 type of FD systems. The derived FD and FTC approaches are verified by two benchmark processes. Contents Overview of FD and FTC Technology Configuration of Nonlinear Observer-Based FD Systems Design of L2 nonlinear Observer-Based FD Systems Design of Weighted Fuzzy Observer-Based FD Systems FTC Configurations for Nonlinear Systems< Application to Benchmark Processes Target Groups Researchers and students in the field of engineering with a focus on fault diagnosis and fault-tolerant control fields The Author Dr. Linlin Li completed her dissertation under the supervision of Prof. Steven X. Ding at the Faculty of Engineering, University of Duisburg-Essen, Germany...

  15. Fault tolerant control of systems with saturations

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik

    2013-01-01

    This paper presents framework for fault tolerant controllers (FTC) that includes input saturation. The controller architecture known from FTC is based on the Youla-Jabr-Bongiorno-Kucera (YJBK) parameterization is extended to handle input saturation. Applying this controller architecture in connec...

  16. Mine-Hoist Active Fault Tolerant Control System and Strategy

    Institute of Scientific and Technical Information of China (English)

    WANG Zhi-jie; WANG Yao-cai; MENG Jiang; ZHAO Peng-cheng; CHANG Yan-wei

    2005-01-01

    Based on fault diagnosis and fault tolerant technologies, the mine-hoist active fault-tolerant control system (MAFCS) is presented with corresponding strategies,, which includes the fault diagnosis module (FDM), the dynamic library (DL) and the fault-tolerant control module (FCM). When a fault is judged from some sensor by FDM, FCM reconfigure the state of MAFCS by calling the parameters from all sub libraries in DL, in order to ensure the reliability and safety of mine hoist. The simulating result shows that, MAFCS is of certain intelligence, which can adopt the corresponding control strategies according to different fault modes, even when there are quite difference between the real data and the prior fault modes.

  17. From fault classification to fault tolerance for multi-agent systems

    CERN Document Server

    Potiron, Katia; Taillibert, Patrick

    2013-01-01

    Faults are a concern for Multi-Agent Systems (MAS) designers, especially if the MAS are built for industrial or military use because there must be some guarantee of dependability. Some fault classification exists for classical systems, and is used to define faults. When dependability is at stake, such fault classification may be used from the beginning of the system's conception to define fault classes and specify which types of faults are expected. Thus, one may want to use fault classification for MAS; however, From Fault Classification to Fault Tolerance for Multi-Agent Systems argues that

  18. Fault-tolerant system for catastrophic faults in AMR sensors

    NARCIS (Netherlands)

    Zambrano, Andreina; Kerkhoff, Hans G.

    2015-01-01

    Anisotropic Magnetoresistance angle sensors are widely used in automotive applications considered to be safety-critical applications. Therefore dependability is an important requirement and fault-tolerant strategies must be used to guarantee the correct operation of the sensors even in case of failu

  19. Software fault tolerance

    OpenAIRE

    Kazinov, Tofik Hasanaga; Mostafa, Jalilian Shahrukh

    2009-01-01

    Because of our present inability to produce errorfree software, software fault tolerance is and will contiune to be an important consideration in software system. The root cause of software design errors in the complexity of the systems. This paper surveys various software fault tolerance techniquest and methodologies. They are two gpoups: Single version and Multi version software fault tolerance techniques. It is expected that software fault tolerance research will benefit from this research...

  20. Fault Tolerance in Distributed Systems using Fused State Machines

    OpenAIRE

    Balasubramanian, Bharath; Garg, Vijay K

    2013-01-01

    Replication is a standard technique for fault tolerance in distributed systems modeled as deterministic finite state machines (DFSMs or machines). To correct f crash or f/2 Byzantine faults among n different machines, replication requires nf additional backup machines. We present a solution called fusion that requires just f additional backup machines. First, we build a framework for fault tolerance in DFSMs based on the notion of Hamming distances. We introduce the concept of an (f,m)-fusion...

  1. Fault tolerant system design for uninterruptible power supplies

    Directory of Open Access Journals (Sweden)

    B. Y. Volochiy

    2012-02-01

    Full Text Available The problem of design for reliability of a fault tolerant system for uninterruptible power supplies is considered. Configuration of a fault tolerant system determines the structure of an uninterruptible power supply: power supply built from modules of the same type, stand-by sliding reserve for them, twice total reserve of the power supply with two accumulator batteries, the controls and diagnostics means. The developed tool for automated analytical model of fault tolerant systems generation and illustration of its capabilities in determination of requirements for repair service and accumulator batteries are given.

  2. Active Fault Tolerant Control of Livestock Stable Ventilation System

    DEFF Research Database (Denmark)

    Gholami, Mehdi

    2011-01-01

    affine (PWA) components such as dead-zones, saturation, etc or contain piecewise nonlinear models which is the case for the climate control systems of the stables. Fault tolerant controller (FTC) is based on a switching scheme between a set of predefined passive fault tolerant controller (PFTC......). In the FTC part of the thesis, first a passive fault tolerant controller (PFTC) based on state feed-back is proposed for discretetime PWA systems. only actuator faults are considered. By dissipativity theory and H1 analysis, the problem is cast as a set of linear matrix inequalities (LMIs). In the next...... are not included, while due to the physical limitation, the input signal can not have any value. In continuing, a passive fault tolerant controller (PFTC) based on state feedback is proposed to track a reference signal while the control inputs are bounded....

  3. Fault-Tolerant Systems with Concurrent Error-Locating Capability

    Institute of Scientific and Technical Information of China (English)

    JIANG JianHui(江建慧); MIN YingHua(闵应骅); PENG ChengLian(彭澄廉)

    2003-01-01

    Fault-tolerant systems have found wide applications in military, industrial andcommercial areas. Most of these systems are constructed by multiple-modular redundancy or er-ror control coding techniques. They need some fault-tolerant specific components (such as voter,switcher, encoder, or decoder) to implement error-detecting or error-correcting functions. However,the problem of error detection, location or correction for fault-tolerance specific components them-selves has not been solved properly so far. Thus, the dependability of a whole fault-tolerant systemwill be greatly affected. This paper presents a theory of robust fault-masking digital circuits forcharacterizing fault-tolerant systems with the ability of concurrent error location and a new schemeof dual-modular redundant systems with partially robust fault-masking property. A basic robustfault-masking circuit is composed of a basic functional circuit and an error-locating corrector. Sucha circuit not only has the ability of concurrent error correction, but also has the ability of concurrenterror location. According to this circuit model, for a partially robust fault-masking dual-modularredundant system, two redundant modules based on alternating-complementary logic consist of thebasic functional circuit. An error-correction specific circuit named as alternating-complementarycorrector is used as the error-locating corrector. The performance (such as hardware complexity,time delay) of the scheme is analyzed.

  4. Sensor Fault Tolerant Generic Model Control for Nonlinear Systems

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A modified Strong Tracking Filter (STF) is used to develop a new approach to sensor fault tolerant control. Generic Model Control (GMC) is used to control the nonlinear process while the process runs normally because of its robust control performance. If a fault occurs in the sensor, a sensor bias vector is then introduced to the output equation of the process model. The sensor bias vector is estimated on-line during every control period using the STF. The estimated sensor bias vector is used to develop a fault detection mechanism to supervise the sensors. When a sensor fault occurs, the conventional GMC is switched to a fault tolerant control scheme, which is, in essence, a state estimation and output prediction based GMC. The laboratory experimental results on a three-tank system demonstrate the effectiveness of the proposed Sensor Fault Tolerant Generic Model Control (SFTGMC) approach.

  5. H infinity Integrated Fault Estimation and Fault Tolerant Control of Discrete-time Piecewise Linear Systems

    DEFF Research Database (Denmark)

    Tabatabaeipour, Seyed Mojtaba; Bak, Thomas

    2012-01-01

    In this paper we consider the problem of fault estimation and accommodation for discrete time piecewise linear systems. A robust fault estimator is designed to estimate the fault such that the estimation error converges to zero and H∞ performance of the fault estimation is minimized. Then......, the estimate of fault is used to compensate for the effect of the fault. Hence, using the estimate of fault, a fault tolerant controller using a piecewise linear static output feedback is designed such that it stabilizes the system and provides an upper bound on the H∞ performance of the faulty system....... Sufficient conditions for the existence of robust fault estimator and fault tolerant controller are derived in terms of linear matrix inequalities. Upper bounds on the H∞ performance can be minimized by solving convex optimization problems with linear matrix inequality constraints. The efficiency...

  6. Fault-tolerant computation with higher-dimensional systems

    Energy Technology Data Exchange (ETDEWEB)

    Gottesman, D.

    1998-07-01

    Instead of a quantum computer where the fundamental units are 2-dimensional qubits, the author can consider a quantum computer made up of d-dimensional systems. There is a straightforward generalization of the class of stabilizer codes to d-dimensional systems, and he will discuss the theory of fault-tolerant computation using such codes. He proves that universal fault-tolerant computation is possible with any higher-dimensional stabilizer code for prime d.

  7. Fault tolerant hypercube computer system architecture

    Science.gov (United States)

    Madan, Herb S. (Inventor); Chow, Edward (Inventor)

    1989-01-01

    A fault-tolerant multiprocessor computer system of the hypercube type comprising a hierarchy of computers of like kind which can be functionally substituted for one another as necessary is disclosed. Communication between the working nodes is via one communications network while communications between the working nodes and watch dog nodes and load balancing nodes higher in the structure is via another communications network separate from the first. A typical branch of the hierarchy reporting to a master node or host computer comprises, a plurality of first computing nodes; a first network of message conducting paths for interconnecting the first computing nodes as a hypercube. The first network provides a path for message transfer between the first computing nodes; a first watch dog node; and a second network of message connecting paths for connecting the first computing nodes to the first watch dog node independent from the first network, the second network provides an independent path for test message and reconfiguration affecting transfers between the first computing nodes and the first switch watch dog node. There is additionally, a plurality of second computing nodes; a third network of message conducting paths for interconnecting the second computing nodes as a hypercube. The third network provides a path for message transfer between the second computing nodes; a fourth network of message conducting paths for connecting the second computing nodes to the first watch dog node independent from the third network. The fourth network provides an independent path for test message and reconfiguration affecting transfers between the second computing nodes and the first watch dog node; and a first multiplexer disposed between the first watch dog node and the second and fourth networks for allowing the first watch dog node to selectively communicate with individual ones of the computing nodes through the second and fourth networks; as well as, a second watch dog node

  8. Measurement and analysis of operating system fault tolerance

    Science.gov (United States)

    Lee, I.; Tang, D.; Iyer, R. K.

    1992-01-01

    This paper demonstrates a methodology to model and evaluate the fault tolerance characteristics of operational software. The methodology is illustrated through case studies on three different operating systems: the Tandem GUARDIAN fault-tolerant system, the VAX/VMS distributed system, and the IBM/MVS system. Measurements are made on these systems for substantial periods to collect software error and recovery data. In addition to investigating basic dependability characteristics such as major software problems and error distributions, we develop two levels of models to describe error and recovery processes inside an operating system and on multiple instances of an operating system running in a distributed environment. Based on the models, reward analysis is conducted to evaluate the loss of service due to software errors and the effect of the fault-tolerance techniques implemented in the systems. Software error correlation in multicomputer systems is also investigated.

  9. Fault tolerant highly reliable inertial navigation system

    Science.gov (United States)

    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.

  10. Data-driven design of fault diagnosis and fault-tolerant control systems

    CERN Document Server

    Ding, Steven X

    2014-01-01

    Data-driven Design of Fault Diagnosis and Fault-tolerant Control Systems presents basic statistical process monitoring, fault diagnosis, and control methods, and introduces advanced data-driven schemes for the design of fault diagnosis and fault-tolerant control systems catering to the needs of dynamic industrial processes. With ever increasing demands for reliability, availability and safety in technical processes and assets, process monitoring and fault-tolerance have become important issues surrounding the design of automatic control systems. This text shows the reader how, thanks to the rapid development of information technology, key techniques of data-driven and statistical process monitoring and control can now become widely used in industrial practice to address these issues. To allow for self-contained study and facilitate implementation in real applications, important mathematical and control theoretical knowledge and tools are included in this book. Major schemes are presented in algorithm form and...

  11. Fault-tolerant Control Systems-An Introductory Overview

    Institute of Scientific and Technical Information of China (English)

    Jin Jiang

    2005-01-01

    This paper presents an introductory overview on the development of fault-tolerant control systems. For this reason, the paper is written in a tutorial fashion to summarize some of the important results in this subject area deliberately without going into details in any of them. However, key references are provided from which interested readers can obtain more detailed information on a particular subject. It is necessary to mention that, throughout this paper, no efforts were made to provide an exhaustive coverage on the subject matter. In fact, it is far from it. The paper merely represents the view and experience of its author. It can very well be that some important issues or topics were left out unintentionally. If that is the case, the author sincerely apologizes in advance.After a brief account of fault-tolerant control systems, particularly on the original motivations, and the concept of redundancies, the paper reviews the development of fault-tolerant control systems with highlights to several important issues from a historical perspective. The general approaches to fault-tolerant control has been divided into passive, active, and hybrid approaches. The analysis techniques for active fault-tolerant control systems are also discussed. Practical applications of faulttolerant control are highlighted from a practical and industrial perspective. Finally, some critical issues in this area are discussed as open problems for future research/development in this emerging field.

  12. Guaranteed Cost Fault-Tolerant Control for Networked Control Systems with Sensor Faults

    Directory of Open Access Journals (Sweden)

    Qixin Zhu

    2015-01-01

    Full Text Available For the large scale and complicated structure of networked control systems, time-varying sensor faults could inevitably occur when the system works in a poor environment. Guaranteed cost fault-tolerant controller for the new networked control systems with time-varying sensor faults is designed in this paper. Based on time delay of the network transmission environment, the networked control systems with sensor faults are modeled as a discrete-time system with uncertain parameters. And the model of networked control systems is related to the boundary values of the sensor faults. Moreover, using Lyapunov stability theory and linear matrix inequalities (LMI approach, the guaranteed cost fault-tolerant controller is verified to render such networked control systems asymptotically stable. Finally, simulations are included to demonstrate the theoretical results.

  13. Design of fault tolerant control system for steam generator using

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Myung Ki; Seo, Mi Ro [Korea Electric Power Research Institute, Taejon (Korea, Republic of)

    1998-12-31

    A controller and sensor fault tolerant system for a steam generator is designed with fuzzy logic. A structure of the proposed fault tolerant redundant system is composed of a supervisor and two fuzzy weighting modulators. A supervisor alternatively checks a controller and a sensor induced performances to identify which part, a controller or a sensor, is faulty. In order to analyze controller induced performance both an error and a change in error of the system output are chosen as fuzzy variables. The fuzzy logic for a sensor induced performance uses two variables : a deviation between two sensor outputs and its frequency. Fuzzy weighting modulator generates an output signal compensated for faulty input signal. Simulations show that the proposed fault tolerant control scheme for a steam generator regulates well water level by suppressing fault effect of either controllers or sensors. Therefore through duplicating sensors and controllers with the proposed fault tolerant scheme, both a reliability of a steam generator control and sensor system and that of a power plant increase even more. 2 refs., 9 figs., 1 tab. (Author)

  14. GEMS: A Fault Tolerant Grid Job Management System

    OpenAIRE

    Tadepalli, Sriram Satish

    2003-01-01

    The Grid environments are inherently unstable. Resources join and leave the environment without any prior notification. Application fault detection, checkpointing and restart is of foremost importance in the Grid environments. The need for fault tolerance is especially acute for large parallel applications since the failure rate grows with the number of processors and the duration of the computation. A Grid job management system hides the heterogeneity of the Grid and the complexity of the ...

  15. Fault-tolerant design of picture archiving and communication systems

    International Nuclear Information System (INIS)

    Reliability is perhaps the most important attribute of a PACS. Any downtime of the system may seriously affect patient care. This paper describes fault-tolerant measures employed in the design of a hospital-wide PACS. Six fault-tolerant measures have been implemented: hardware redundance (networks and archives), data-base backups, monitoring routines for local host processes and network status; uninterruptible power supplied, structured software design techniques, and in-service training of all radiology technologists. A PACS consisting of 13 acquisition nodes, two optical archiving nodes, two data-base server nodes, and five workstation nodes has been developed

  16. Trends in reliability modeling technology for fault tolerant systems

    Science.gov (United States)

    Bavuso, S. J.

    1979-01-01

    Developments in reliability modeling for large fault tolerant avionic computing systems are presented. Issues of state size and complexity, fault coverage, and practical computation are addressed. A two-fold developmental effort is described based on the structural and fault coverage modeling approaches. A technique which was successfully applied to an 865 state pure death stationary Markov model is presented. Of particular interest is a short computer program which executes very quickly to produce reliability results of a large state space model. This model also incorporates fault coverage states for processor, memory, and bus line replaceable units. A second structural reliability modeling scheme is aimed at solving nonstationary Markov models. This technique provides the tool required for studying the reliability of systems with nonconstant failure rates and includes intermittent/transient faults, electronic hardware which exhibits decreasing failure rates, and hydromechanical devices which typically have wearout failure mechanisms. Several aspects of fault coverage, including modeling and data measurement of intermittent/transient faults and latent faults, are elucidated and illustrated. The CARE II (computer-aided reliability estimation) coverage is presented and shortcomings to be eliminated are discussed.

  17. Fault tolerance control for proton exchange membrane fuel cell systems

    Science.gov (United States)

    Wu, Xiaojuan; Zhou, Boyang

    2016-08-01

    Fault diagnosis and controller design are two important aspects to improve proton exchange membrane fuel cell (PEMFC) system durability. However, the two tasks are often separately performed. For example, many pressure and voltage controllers have been successfully built. However, these controllers are designed based on the normal operation of PEMFC. When PEMFC faces problems such as flooding or membrane drying, a controller with a specific design must be used. This paper proposes a unique scheme that simultaneously performs fault diagnosis and tolerance control for the PEMFC system. The proposed control strategy consists of a fault diagnosis, a reconfiguration mechanism and adjustable controllers. Using a back-propagation neural network, a model-based fault detection method is employed to detect the PEMFC current fault type (flooding, membrane drying or normal). According to the diagnosis results, the reconfiguration mechanism determines which backup controllers to be selected. Three nonlinear controllers based on feedback linearization approaches are respectively built to adjust the voltage and pressure difference in the case of normal, membrane drying and flooding conditions. The simulation results illustrate that the proposed fault tolerance control strategy can track the voltage and keep the pressure difference at desired levels in faulty conditions.

  18. Fault-tolerant clock synchronization validation methodology. [in computer systems

    Science.gov (United States)

    Butler, Ricky W.; Palumbo, Daniel L.; Johnson, Sally C.

    1987-01-01

    A validation method for the synchronization subsystem of a fault-tolerant computer system is presented. The high reliability requirement of flight-crucial systems precludes the use of most traditional validation methods. The method presented utilizes formal design proof to uncover design and coding errors and experimentation to validate the assumptions of the design proof. The experimental method is described and illustrated by validating the clock synchronization system of the Software Implemented Fault Tolerance computer. The design proof of the algorithm includes a theorem that defines the maximum skew between any two nonfaulty clocks in the system in terms of specific system parameters. Most of these parameters are deterministic. One crucial parameter is the upper bound on the clock read error, which is stochastic. The probability that this upper bound is exceeded is calculated from data obtained by the measurement of system parameters. This probability is then included in a detailed reliability analysis of the system.

  19. Multilevel Gain Cell Arrays for Fault-Tolerant VLSI Systems

    OpenAIRE

    Khalid, Muhammad Umer

    2011-01-01

    Embedded memories dominate area, power and cost of modern very large scale integrated circuits system on chips ( VLSI SoCs). Furthermore, due to process variations, it becomes challenging to design reliable energy efficient systems. Therefore, fault-tolerant designs will be area efficient, cost effective and have low power consumption. The idea of this project is to design embedded memories where reliability is intentionally compromised to increase storage density. Gain cell memories are smal...

  20. Performance-Oriented Fault Tolerance in Computing Systems

    OpenAIRE

    Borodin, D

    2010-01-01

    In this dissertation we address the overhead reduction of fault tolerance (FT) techniques. Due to technology trends such as decreasing feature sizes and lowering voltage levels, FT is becoming increasingly important in modern computing systems. FT techniques are based on some form of redundancy. It can be space redundancy (additional hardware), time redundancy (multiple executions), and/or information redundancy (additional verification information). This redundancy significantly increases th...

  1. Satisfactory fault-tolerant controller design for uncertain systems subject to actuator faults

    Institute of Scientific and Technical Information of China (English)

    Zhang Dengfeng; Su Hongye; Wang Zhiquan

    2008-01-01

    Based on satisfactory control strategy, a new method for robust passive fault tolerant controller is proposed for a class of uncertain discrete-time systems subject to actuator faults. The state-feedback gain matrix is calculated by linear matrix inequality (LMI) technique. The designed controller guarantees that the closed-loop system meets the pre-specified consistent constraints on circular pole index and steady-state variance index simultaneously for normal case and possible actuator fault case. The consistency of the performance indices is discussed. Furthermore, with the mentioned indices constraints, a solution is obtained by convex optimal technique for the robust satisfactory fault-tolerant controller with optimal control-cost.

  2. Industrial Cost-Benefit Assessment for Fault-tolerant Control Systems

    DEFF Research Database (Denmark)

    Thybo, C.; Blanke, M.

    1998-01-01

    at a system level. In a design phase for an industrial system, possibilities span from fail safe design where any single point failure is accommodated by hardware, over fault-tolerant design where selected faults are handled without extra hardware, to fault-ignorant design where no extra precaution is taken......Economic aspects are decisive for industrial acceptance of research concepts including the promising ideas in fault tolerant control. Fault tolerance is the ability of a system to detect, isolate and accommodate a fault, such that simple faults in a sub-system do not develop into failures...

  3. Diagnosis and Fault-Tolerant Control for Thruster-Assisted Position Mooring System

    DEFF Research Database (Denmark)

    Nguyen, Trong Dong; Blanke, Mogens; Sørensen, Asgeir

    2007-01-01

    Development of fault-tolerant control systems is crucial to maintain safe operation of o®shore installations. The objective of this paper is to develop a fault- tolerant control for thruster-assisted position mooring (PM) system with faults occurring in the mooring lines. Faults in line's pretens......Development of fault-tolerant control systems is crucial to maintain safe operation of o®shore installations. The objective of this paper is to develop a fault- tolerant control for thruster-assisted position mooring (PM) system with faults occurring in the mooring lines. Faults in line......'s pretension or line breaks will degrade the performance of the positioning of the vessel. Faults will be detected and isolated through a fault diagnosis procedure. When faults are detected, they can be accommodated through the control action in which only parameter of the controlled plant has to be updated to...

  4. Sliding mode based fault detection, reconstruction and fault tolerant control scheme for motor systems.

    Science.gov (United States)

    Mekki, Hemza; Benzineb, Omar; Boukhetala, Djamel; Tadjine, Mohamed; Benbouzid, Mohamed

    2015-07-01

    The fault-tolerant control problem belongs to the domain of complex control systems in which inter-control-disciplinary information and expertise are required. This paper proposes an improved faults detection, reconstruction and fault-tolerant control (FTC) scheme for motor systems (MS) with typical faults. For this purpose, a sliding mode controller (SMC) with an integral sliding surface is adopted. This controller can make the output of system to track the desired position reference signal in finite-time and obtain a better dynamic response and anti-disturbance performance. But this controller cannot deal directly with total system failures. However an appropriate combination of the adopted SMC and sliding mode observer (SMO), later it is designed to on-line detect and reconstruct the faults and also to give a sensorless control strategy which can achieve tolerance to a wide class of total additive failures. The closed-loop stability is proved, using the Lyapunov stability theory. Simulation results in healthy and faulty conditions confirm the reliability of the suggested framework. PMID:25747198

  5. A fault tolerant superheat control strategy for supermarket refrigeration systems

    DEFF Research Database (Denmark)

    Vinther, Kasper; Izadi-Zamanabadi, Roozbeh; Rasmussen, Henrik;

    2013-01-01

    In this paper, a fault tolerant control (FTC) strategy is proposed for evaporator superheat control in supermarket refrigeration systems. Conventional control uses a pressure and temperature sensor for this purpose, however, the pressure sensor can fail to function. A contingency control strategy......, based on a maximum slope-seeking control method and only a single temperature sensor, is developed to drive the evaporator outlet temperature to a level that gives a suitable superheat of the refrigerant. The FTC strategy requires no a priori system knowledge or additional hardware and functions...... system....

  6. Fault Tolerant Software: a Multi Agent System Solution

    DEFF Research Database (Denmark)

    Caponetti, Fabio; Bergantino, Nicola; Longhi, Sauro

    2009-01-01

    Development of high dependable systems remains a labour intensive task. This paper explores recent advances on the adaptation of the software agent architecture for control application while looking to dependability issues. Multiple agent systems theory will be reviewed giving methods to supervise...... it. Software ageing is shown to be the most common problem and rejuvenation its counteract. The paper will show how an agent population can be monitored, faulty agents isolated and reloaded in a healthy state, hence rejuvenated. The aim is to propose an architecture as basis for the design of control...... software able to tolerate faults and residual bugs without the need of maintenance stops....

  7. Fault-Tolerant Relative Navigation System (RNS) for Docking Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A method is propsed to develop a sensor fusion process for blending GPS/IMU/EO data for fault tolerant rendezvous and docking of spacecraft. The methodology takes...

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

    Science.gov (United States)

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

    1992-01-01

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

  9. Diagnostic software and fault tolerant microprocessor based system architectures

    International Nuclear Information System (INIS)

    In numerous industrial applications including power generation, the availability of electronic systems to perform the tasks assigned has become a major issue. At the same time, the functional complexity of these systems has increased enormously. Fortunately, the arrival of cost effective microprocessor based hardware has given the system designer a cadre of techniques to ensure the desired degree of system integrity and availability. These include: dynamic redundancy, isolation, functional diversity, built-in self-tests, embedded test subsystems, communications, error checking and error correcting codes, etc. The choice among the available techniques is generally heuristic and depends greatly on the structure of major components and systems external to the electronic system itself as well as the postulated faults and their relative frequency. Indiscriminate use of these techniques will inevitably increase cost and reduce maintainability while actually reducing system availability and reliability. The issues and the application of these techniques are discussed by describing recent examples of fault tolerant microprocessor based system architectures which include the Plant Safety Monitoring System, the EAGLE-21 Process Protection System and the Advanced Rod Position Indication System for pressurized water reactors. Each of these systems utilize unique internal architectures that address the reliability, availability, and the communications issues while improving maintainability and man-machine interfaces

  10. Fault Tolerant Feedback Control

    DEFF Research Database (Denmark)

    Stoustrup, Jakob; Niemann, H.

    2001-01-01

    An architecture for fault tolerant feedback controllers based on the Youla parameterization is suggested. It is shown that the Youla parameterization will give a residual vector directly in connection with the fault diagnosis part of the fault tolerant feedback controller. It turns out...... that there is a separation be-tween the feedback controller and the fault tolerant part. The closed loop feedback properties are handled by the nominal feedback controller and the fault tolerant part is handled by the design of the Youla parameter. The design of the fault tolerant part will not affect the design...... of the nominal feedback con-troller....

  11. Disturbance observer based fault estimation and dynamic output feedback fault tolerant control for fuzzy systems with local nonlinear models.

    Science.gov (United States)

    Han, Jian; Zhang, Huaguang; Wang, Yingchun; Liu, Yang

    2015-11-01

    This paper addresses the problems of fault estimation (FE) and fault tolerant control (FTC) for fuzzy systems with local nonlinear models, external disturbances, sensor and actuator faults, simultaneously. Disturbance observer (DO) and FE observer are designed, simultaneously. Compared with the existing results, the proposed observer is with a wider application range. Using the estimation information, a novel fuzzy dynamic output feedback fault tolerant controller (DOFFTC) is designed. The controller can be used for the fuzzy systems with unmeasurable local nonlinear models, mismatched input disturbances, and measurement output affecting by sensor faults and disturbances. At last, the simulation shows the effectiveness of the proposed methods. PMID:26456728

  12. Analysis and optimization of fault-tolerant embedded systems with hardened processors

    DEFF Research Database (Denmark)

    Izosimov, Viacheslav; Polian, Ilia; Pop, Paul

    2009-01-01

    In this paper we propose an approach to the design optimization of fault-tolerant hard real-time embedded systems, which combines hardware and software fault tolerance techniques. We trade-off between selective hardening in hardware and process reexecution in software to provide the required levels...... of fault tolerance against transient faults with the lowest-possible system costs. We propose a system failure probability (SFP) analysis that connects the hardening level with the maximum number of reexecutions in software. We present design optimization heuristics, to select the fault...

  13. Adaptive fault-tolerant control of linear systems with actuator saturation and L2-disturbances

    Institute of Scientific and Technical Information of China (English)

    Wei GUAN; Guanghong YANG

    2009-01-01

    This paper studies the problem of designing adaptive fault-tolerant H-infinity controllers for linear timeinvariant systems with actuator saturation. The disturbance tolerance ability of the closed-loop system is measured by an optimal index. The notion of an adaptive H-infinity performance index is proposed to describe the disturbance attenuation performances of closed-loop systems. New methods for designing indirect adaptive fault-tolerant controllers via state feedback are presented for actuator fault compensations. Based on the on-line estimation of eventual faults, the adaptive fault-tolerant controller parameters are updated automatically to compensate for the fault effects on systems. The designs are developed in the framework of the linear matrix inequality (LMI) approach, which can guarantee the disturbance tolerance ability and adaptive H-infinity performances of closed-loop systems in the cases of actuator saturation and actuator failures. An example is given to illustrate the efficiency of the design method.

  14. Modeling the Fault Tolerant Capability of a Flight Control System: An Exercise in SCR Specification

    Science.gov (United States)

    Alexander, Chris; Cortellessa, Vittorio; DelGobbo, Diego; Mili, Ali; Napolitano, Marcello

    2000-01-01

    In life-critical and mission-critical applications, it is important to make provisions for a wide range of contingencies, by providing means for fault tolerance. In this paper, we discuss the specification of a flight control system that is fault tolerant with respect to sensor faults. Redundancy is provided by analytical relations that hold between sensor readings; depending on the conditions, this redundancy can be used to detect, identify and accommodate sensor faults.

  15. Fault diagnosis and fault-tolerant control strategies for non-linear systems analytical and soft computing approaches

    CERN Document Server

    Witczak, Marcin

    2014-01-01

      This book presents selected fault diagnosis and fault-tolerant control strategies for non-linear systems in a unified framework. In particular, starting from advanced state estimation strategies up to modern soft computing, the discrete-time description of the system is employed Part I of the book presents original research results regarding state estimation and neural networks for robust fault diagnosis. Part II is devoted to the presentation of integrated fault diagnosis and fault-tolerant systems. It starts with a general fault-tolerant control framework, which is then extended by introducing robustness with respect to various uncertainties. Finally, it is shown how to implement the proposed framework for fuzzy systems described by the well-known Takagi–Sugeno models. This research monograph is intended for researchers, engineers, and advanced postgraduate students in control and electrical engineering, computer science,as well as mechanical and chemical engineering.

  16. Fault-tolerant for Electric Vehicles Drive System Sensor Failure

    Directory of Open Access Journals (Sweden)

    Zhang Liwei

    2013-10-01

    Full Text Available When EV failure happens, it needs to take some fault-tolerant method to ensure people’s safety. When the current sensor and speed sensor are out of work, the software fault-tolerant control algorithm switching strategy can be used. This paper has done theoretical analysis of the rotor field-oriented vectoe control algorithm into the open loop constant V/F control algorithm, and the phase angle compensation method is used to reduce the shock of current and torque, and simulation is done in MATLAB/Simulink.    

  17. Application of Joint Parameter Identification and State Estimation to a Fault-Tolerant Robot System

    DEFF Research Database (Denmark)

    Sun, Zhen; Yang, Zhenyu

    2011-01-01

    The joint parameter identification and state estimation technique is applied to develop a fault-tolerant space robot system. The potential faults in the considered system are abrupt parametric faults, which indicate that some system parameters will immediately deviate from their nominal values...

  18. Design Optimization of Time- and Cost-Constrained Fault-Tolerant Distributed Embedded Systems

    DEFF Research Database (Denmark)

    Izosimov, Viacheslav; Pop, Paul; Eles, Petru;

    2005-01-01

    transient faults. Our design optimization approach decides the mapping of processes to processors and the assignment of fault-tolerant policies to processes such that transient faults are tolerated and the timing constraints of the application are satisfied. We present several heuristics which are able......In this paper we present an approach to the design optimization of fault-tolerant embedded systems for safety-critical applications. Processes are statically scheduled and communications are performed using the time-triggered protocol. We use process re-execution and replication for tolerating...

  19. Industrial Cost-Benefit Assessment for Fault-tolerant Control Systems

    DEFF Research Database (Denmark)

    Thybo, C.; Blanke, M.

    1998-01-01

    at a system level. In a design phase for an industrial system, possibilities span from fail safe design where any single point failure is accommodated by hardware, over fault-tolerant design where selected faults are handled without extra hardware, to fault-ignorant design where no extra precaution is taken...... against failure. The paper describes the assessments needed to find the right path for new industrial designs. The economic decisions in the design phase are discussed: cost of different failures, profits associated with available benefits, investments needed for development and life-time support......Economic aspects are decisive for industrial acceptance of research concepts including the promising ideas in fault tolerant control. Fault tolerance is the ability of a system to detect, isolate and accommodate a fault, such that simple faults in a sub-system do not develop into failures...

  20. Boolean Logic with Fault Tolerant Coding

    OpenAIRE

    Alagoz, B. Baykant

    2009-01-01

    Error detectable and error correctable coding in Hamming space was researched to discover possible fault tolerant coding constellations, which can implement Boolean logic with fault tolerant property. Basic logic operators of the Boolean algebra were developed to apply fault tolerant coding in the logic circuits. It was shown that application of three-bit fault tolerant codes have provided the digital system skill of auto-recovery without need for designing additional-fault tolerance mechanisms.

  1. Robust and Active Fault-tolerant Control for a Class of Nonlinear Uncertain Systems

    Institute of Scientific and Technical Information of China (English)

    You-Qing Wang; Dong-Hua Zhou; Li-Heng Liu

    2006-01-01

    A novel integrated design strategy for robust fault diagnosis and fault-tolerant control (FTC) of a class of nonlinear uncertain systems is proposed. The uncertainties considered in this paper are more general than those in other existing works, and faults are described in a new formulation. It is proven that the states of a closed-loop system converge asymptotically to zero even if there are uncertainties and faults in a system. Simulation results on a simple pendulum are presented for illustration.

  2. Passive Fault Tolerant Control of Piecewise Affine Systems Based on H Infinity Synthesis

    DEFF Research Database (Denmark)

    Gholami, Mehdi; Cocquempot, vincent; Schiøler, Henrik;

    2011-01-01

    In this paper we design a passive fault tolerant controller against actuator faults for discretetime piecewise affine (PWA) systems. By using dissipativity theory and H analysis, fault tolerant state feedback controller design is expressed as a set of Linear Matrix Inequalities (LMIs). In the cur......In this paper we design a passive fault tolerant controller against actuator faults for discretetime piecewise affine (PWA) systems. By using dissipativity theory and H analysis, fault tolerant state feedback controller design is expressed as a set of Linear Matrix Inequalities (LMIs......). In the current paper, the PWA system switches not only due to the state but also due to the control input. The method is applied on a large scale livestock ventilation model....

  3. Energy-Aware Synthesis of Fault-Tolerant Schedules for Real-Time Distributed Embedded Systems

    DEFF Research Database (Denmark)

    Poulsen, Kåre Harbo; Pop, Paul; Izosimov, Viacheslav

    2007-01-01

    This paper presents a design optimisation tool for distributed embedded real-time systems that 1) decides mapping, fault-tolerance policy and generates a fault-tolerant schedule, 2) is targeted for hard real-time, 3) has hard reliability goal, 4) generates static schedule for processes and messages...

  4. Towards fault-tolerant decision support systems for ship operator guidance

    DEFF Research Database (Denmark)

    Nielsen, Ulrik Dam; Lajic, Zoran; Jensen, Jørgen Juncher

    2012-01-01

    Fault detection and isolation are very important elements in the design of fault-tolerant decision support systems for ship operator guidance. This study outlines remedies that can be applied for fault diagnosis, when the ship responses are assumed to be linear in the wave excitation. A novel...

  5. An Algebra of Fault Tolerance

    CERN Document Server

    Rao, Shrisha

    2009-01-01

    Every system of any significant size is created by composition from smaller sub-systems or components. It is thus fruitful to analyze the fault-tolerance of a system as a function of its composition. In this paper, two basic types of system composition are described, and an algebra to describe fault tolerance of composed systems is derived. The set of systems forms monoids under the two composition operators, and a semiring when both are concerned. A partial ordering relation between systems is used to compare their fault-tolerance behaviors.

  6. Fault-Tolerant Control of the Road Wheel Subsystem in a Steer-By-Wire System

    Directory of Open Access Journals (Sweden)

    Bing Zheng

    2008-01-01

    Full Text Available This paper describes a fault-tolerant steer-by-wire road wheel control system. With dual motor and dual microcontroller architecture, this system has the capability to tolerate single-point failures without degrading the control system performance. The arbitration bus, mechanical arrangement of motors, and the developed control algorithm allow the system to reconfigure itself automatically in the event of a single-point fault, and assure a smooth reconfiguration process. Both simulation and experimental results illustrate the effectiveness of the proposed fault-tolerant control system.

  7. Efficient Fault Tree Analysis of Complex Fault Tolerant Multiple-Phased Systems

    Institute of Scientific and Technical Information of China (English)

    MO Yuchang; LIU Hongwei; YANG Xiaozong

    2007-01-01

    Fault tolerant multiple phased systems (FTMPS), i.e., systems whose critical components are independently replicated and whose operational life can be partitioned in a set of disjoint periods, are called "phases". Because of their deployment in critical applications, their reliability analysis is a task of primary relevance to validate the designs. Fault tree analysis based on binary decision diagram (BDD) is one of the most commonly used techniques for FTMPS reliability analysis. To utilize the technique the fault tree structure of FTMPS needs to be converted into the corresponding BDD format. Our research work shows that the system BDD generation algorithms presented in the literature are too inefficient to be used for industrial complex FTPMS because of the problems, such as variable ordering and combination of large BDDs. This paper presents a more efficient approach consisting of a flatting pre-processing technique, a proved efficient ordering heuristic and a bottom-up generation algorithm. The approach tries to combine share-variable BDDs by complex combination operation firstly and then combine no-share-variable BDDs using simple combination operation, thus to alvoid the intensive computations caused by large BDD combination operations. An example FTMPS is analyzed to illustrate the advantages of our approach.

  8. Software engineering for fault-tolerant systems. Final technical report, Jan 89-Aug 90

    Energy Technology Data Exchange (ETDEWEB)

    Goel, A.L.; Mansour, N.

    1991-03-01

    The objectives of this study are to (1) assess the current state of the art of fault tolerant software schemes, (2) evaluate the status of various software engineering issues in this context, (3) identify critical gaps in the currently available technology and, (4) provide recommendations for research and development efforts to enhance the technological base of fault tolerant software engineering. Towards these objectives, the authors have discussed several software fault tolerance schemes, studied the available experimental and analytical evidence about their usefulness and assessed the current status of fault tolerant software engineering for sequential and parallel computers. Based on the studies reported here, they feel that the current state-of-the-art of fault tolerant software is mature enough to tolerate design faults in specific circumstances with appropriate provisions of redundancy and allied supporting mechanisms. However, no known fault tolerance technique can guarantee failure-free system operation. Further, it is questionable whether the current approaches are cost-effective in achieving the desired gain in operational software reliability. They feel that what is needed is a systematic, cost effective approach to software development which explicitly addresses the fault tolerance issues throughout the development life-cycle.

  9. Fault tolerance of artificial neural networks with applications in critical systems

    Science.gov (United States)

    Protzel, Peter W.; Palumbo, Daniel L.; Arras, Michael K.

    1992-01-01

    This paper investigates the fault tolerance characteristics of time continuous recurrent artificial neural networks (ANN) that can be used to solve optimization problems. The principle of operations and performance of these networks are first illustrated by using well-known model problems like the traveling salesman problem and the assignment problem. The ANNs are then subjected to 13 simultaneous 'stuck at 1' or 'stuck at 0' faults for network sizes of up to 900 'neurons'. The effects of these faults is demonstrated and the cause for the observed fault tolerance is discussed. An application is presented in which a network performs a critical task for a real-time distributed processing system by generating new task allocations during the reconfiguration of the system. The performance degradation of the ANN under the presence of faults is investigated by large-scale simulations, and the potential benefits of delegating a critical task to a fault tolerant network are discussed.

  10. Fault-Tolerant Design of Spaceborne Mass Memory System

    Institute of Scientific and Technical Information of China (English)

    张宇宁; 常亮; 杨根庆; 李华旺

    2010-01-01

    A fault-tolerant spaceborne mass memory architecture is presented based on entirely commercial-off-theshelf components.The highly modularized and scalable memory kernel supports the hierarchical design and is well suited to redundancy structure.Error correcting code(ECC) and periodical scrubbing are used to deal with bit errors induced by single event upset.For 8-bit wide devices, the parallel Reed Solomon(10, 8) can perform coder/decoder calculations in one clock cycle, achieving a data rate of several Gb/...

  11. Award ER25750: Coordinated Infrastructure for Fault Tolerance Systems Indiana University Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Lumsdaine, Andrew

    2013-03-08

    The main purpose of the Coordinated Infrastructure for Fault Tolerance in Systems initiative has been to conduct research with a goal of providing end-to-end fault tolerance on a systemwide basis for applications and other system software. While fault tolerance has been an integral part of most high-performance computing (HPC) system software developed over the past decade, it has been treated mostly as a collection of isolated stovepipes. Visibility and response to faults has typically been limited to the particular hardware and software subsystems in which they are initially observed. Little fault information is shared across subsystems, allowing little flexibility or control on a system-wide basis, making it practically impossible to provide cohesive end-to-end fault tolerance in support of scientific applications. As an example, consider faults such as communication link failures that can be seen by a network library but are not directly visible to the job scheduler, or consider faults related to node failures that can be detected by system monitoring software but are not inherently visible to the resource manager. If information about such faults could be shared by the network libraries or monitoring software, then other system software, such as a resource manager or job scheduler, could ensure that failed nodes or failed network links were excluded from further job allocations and that further diagnosis could be performed. As a founding member and one of the lead developers of the Open MPI project, our efforts over the course of this project have been focused on making Open MPI more robust to failures by supporting various fault tolerance techniques, and using fault information exchange and coordination between MPI and the HPC system software stack from the application, numeric libraries, and programming language runtime to other common system components such as jobs schedulers, resource managers, and monitoring tools.

  12. Diagnosis and fault-tolerant control

    CERN Document Server

    Blanke, Mogens; Lunze, Jan; Staroswiecki, Marcel

    2016-01-01

    Fault-tolerant control aims at a gradual shutdown response in automated systems when faults occur. It satisfies the industrial demand for enhanced availability and safety, in contrast to traditional reactions to faults, which bring about sudden shutdowns and loss of availability. The book presents effective model-based analysis and design methods for fault diagnosis and fault-tolerant control. Architectural and structural models are used to analyse the propagation of the fault through the process, to test the fault detectability and to find the redundancies in the process that can be used to ensure fault tolerance. It also introduces design methods suitable for diagnostic systems and fault-tolerant controllers for continuous processes that are described by analytical models of discrete-event systems represented by automata. The book is suitable for engineering students, engineers in industry and researchers who wish to get an overview of the variety of approaches to process diagnosis and fault-tolerant contro...

  13. Fault-Tolerant Consensus of Multi-Agent System With Distributed Adaptive Protocol.

    Science.gov (United States)

    Chen, Shun; Ho, Daniel W C; Li, Lulu; Liu, Ming

    2015-10-01

    In this paper, fault-tolerant consensus in multi-agent system using distributed adaptive protocol is investigated. Firstly, distributed adaptive online updating strategies for some parameters are proposed based on local information of the network structure. Then, under the online updating parameters, a distributed adaptive protocol is developed to compensate the fault effects and the uncertainty effects in the leaderless multi-agent system. Based on the local state information of neighboring agents, a distributed updating protocol gain is developed which leads to a fully distributed continuous adaptive fault-tolerant consensus protocol design for the leaderless multi-agent system. Furthermore, a distributed fault-tolerant leader-follower consensus protocol for multi-agent system is constructed by the proposed adaptive method. Finally, a simulation example is given to illustrate the effectiveness of the theoretical analysis.

  14. Diagnosis and Fault-tolerant Control

    DEFF Research Database (Denmark)

    Blanke, Mogens; Kinnaert, Michel; Lunze, Jan;

    that can be used to ensure fault tolerance. Design methods for diagnostic systems and fault-tolerant controllers are presented for processes that are described by analytical models, by discrete-event models or that can be dealt with as quantised systems. Four case studies on pilot processes show......The book presents effective model-based analysis and design methods for fault diagnosis and fault-tolerant control. Architectural and structural models are used to analyse the propagation of the fault through the process, to test the fault detectability and to find the redundancies in the process......-tolerant control....

  15. Novel active fault-tolerant control scheme and its application to a double inverted pendulum system

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    On the basis of the gain-scheduled H∞ design strategy,a novel active fault-tolerant control scheme is proposed.Under the assumption that the effects of faults on the state-space matrices of systems can be of affine parameter dependence,a reconfigurable robust H∞ linear parameter varying controller is developed.The designed controller is a function of the fault effect factors that can be derived online by using a well-trained neural network.To demonstrate the effectiveness of the proposed method,a double inverted pendulum system,with a fault in the motor tachometer loop,is considered.

  16. Advanced information processing system: The Army fault tolerant architecture conceptual study. Volume 1: Army fault tolerant architecture overview

    Science.gov (United States)

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

    1992-01-01

    Digital computing systems needed for Army programs such as the Computer-Aided Low Altitude Helicopter Flight Program and the Armored Systems Modernization (ASM) vehicles may be characterized by high computational throughput and input/output bandwidth, hard real-time response, high reliability and availability, and maintainability, testability, and producibility requirements. In addition, such a system should be affordable to produce, procure, maintain, and upgrade. To address these needs, the Army Fault Tolerant Architecture (AFTA) is being designed and constructed under a three-year program comprised of a conceptual study, detailed design and fabrication, and demonstration and validation phases. Described here are the results of the conceptual study phase of the AFTA development. Given here is an introduction to the AFTA program, its objectives, and key elements of its technical approach. A format is designed for representing mission requirements in a manner suitable for first order AFTA sizing and analysis, followed by a discussion of the current state of mission requirements acquisition for the targeted Army missions. An overview is given of AFTA's architectural theory of operation.

  17. Validation Methods Research for Fault-Tolerant Avionics and Control Systems: Working Group Meeting, 2

    Science.gov (United States)

    Gault, J. W. (Editor); Trivedi, K. S. (Editor); Clary, J. B. (Editor)

    1980-01-01

    The validation process comprises the activities required to insure the agreement of system realization with system specification. A preliminary validation methodology for fault tolerant systems documented. A general framework for a validation methodology is presented along with a set of specific tasks intended for the validation of two specimen system, SIFT and FTMP. Two major areas of research are identified. First, are those activities required to support the ongoing development of the validation process itself, and second, are those activities required to support the design, development, and understanding of fault tolerant systems.

  18. The Impact of a Fault Tolerant MPI on Scalable Systems Services and Applications

    Energy Technology Data Exchange (ETDEWEB)

    Graham, Richard L [ORNL; Hursey, Joshua J [ORNL; Vallee, Geoffroy R [ORNL; Naughton, III, Thomas J [ORNL; Boehm, Swen [ORNL

    2012-01-01

    Exascale targeted scientific applications must be prepared for a highly concurrent computing environment where failure will be a regular event during execution. Natural and algorithm-based fault tolerance (ABFT) techniques can often manage failures more efficiently than traditional checkpoint/restart techniques alone. Central to many petascale applications is an MPI standard that lacks support for ABFT. The Run-Through Stabilization (RTS) proposal, under consideration for MPI 3, allows an application to continue execution when processes fail. The requirements of scalable, fault tolerant MPI implementations and applications will stress the capabilities of many system services. System services must evolve to efficiently support such applications and libraries in the presence of system component failures. This paper discusses how the RTS proposal impacts system services, highlighting specific requirements. Early experimentation results from Cray systems at ORNL using prototype MPI and runtime implementations are presented. Additionally, this paper outlines fault tolerance techniques targeted at leadership class applications.

  19. Energy-efficient fault tolerance in multiprocessor real-time systems

    Science.gov (United States)

    Guo, Yifeng

    The recent progress in the multiprocessor/multicore systems has important implications for real-time system design and operation. From vehicle navigation to space applications as well as industrial control systems, the trend is to deploy multiple processors in real-time systems: systems with 4 -- 8 processors are common, and it is expected that many-core systems with dozens of processing cores will be available in near future. For such systems, in addition to general temporal requirement common for all real-time systems, two additional operational objectives are seen as critical: energy efficiency and fault tolerance. An intriguing dimension of the problem is that energy efficiency and fault tolerance are typically conflicting objectives, due to the fact that tolerating faults (e.g., permanent/transient) often requires extra resources with high energy consumption potential. In this dissertation, various techniques for energy-efficient fault tolerance in multiprocessor real-time systems have been investigated. First, the Reliability-Aware Power Management (RAPM) framework, which can preserve the system reliability with respect to transient faults when Dynamic Voltage Scaling (DVS) is applied for energy savings, is extended to support parallel real-time applications with precedence constraints. Next, the traditional Standby-Sparing (SS) technique for dual processor systems, which takes both transient and permanent faults into consideration while saving energy, is generalized to support multiprocessor systems with arbitrary number of identical processors. Observing the inefficient usage of slack time in the SS technique, a Preference-Oriented Scheduling Framework is designed to address the problem where tasks are given preferences for being executed as soon as possible (ASAP) or as late as possible (ALAP). A preference-oriented earliest deadline (POED) scheduler is proposed and its application in multiprocessor systems for energy-efficient fault tolerance is

  20. Science Letters: Low-cost fault tolerance in evolvable multiprocessor systems: a graceful degradation approach

    Institute of Scientific and Technical Information of China (English)

    Shervin VAKILI; Sied Mehdi FAKHRAIE; Siamak MOHAMMADI; Ali AHMADI

    2009-01-01

    The evolvable multiprocessor (EvoMP), as a novel multiprocessor system-on-chip (MPSoC) machine with evolvable task decomposition and scheduling, claims a major feature of low-cost and efficient fault tolerance. Non-centralized control and adaptive distribution of the program among the available processors are two major capabilities of this platform, which remarkably help to achieve an efficient fault tolerance scheme. This letter presents the operational as well as architectural details of this fault tolerance scheme. In this method, when a processor becomes faulty, it will be eliminated of contribution in program execution in remaining run-time. This method also utilizes dynamic rescheduling capability of the system to achieve the maximum possible efficiency after processor reduction. The results confirm the efficiency and remarkable advantages of the proposed approach over common redundancy based techniques in similar systems.

  1. Architecture for Intrusion Detection System with Fault Tolerance Using Mobile Agent

    Directory of Open Access Journals (Sweden)

    Chintan Bhatt

    2011-10-01

    Full Text Available This paper is a survey of the work, done for making an IDS fault tolerant.Architecture of IDS that usesmobile Agent provides higher scalability. Mobile Agent uses Platform for detecting Intrusions using filterAgent, co-relater agent, Interpreter agent and rule database. When server (IDS Monitor goes down,other hosts based on priority takes Ownership. This architecture uses decentralized collection andanalysis for identifying Intrusion. Rule sets are fed based on user-behaviour or applicationbehaviour.This paper suggests that intrusion detection system (IDS must be fault tolerant; otherwise, theintruder may first subvert the IDS then attack the target system at will.

  2. A real-time fault-tolerant scheduling algorithm with low dependability cost in on-board computer system

    Institute of Scientific and Technical Information of China (English)

    WANG Pei-dong; WEI Zhen-hua

    2008-01-01

    To make the on-board computer system more dependable and real-time in a satellite, an algorithm of the fault-tolerant scheduling in the on-board computer system with high priority recovery is proposed in this paper. This algorithm can schedule the on-board fault-tolerant tasks in real time. Due to the use of dependability cost, the overhead of scheduling the fault-tolerant tasks can be reduced. The mechanism of the high priority recovery will improve the response to recovery tasks. The fault-tolerant scheduling model is presented simulation results validate the correctness and feasibility of the proposed algorithm.

  3. An architecture for fault tolerant controllers

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik; Stoustrup, Jakob

    2005-01-01

    degradation in the sense of guaranteed degraded performance. A number of fault diagnosis problems, fault tolerant control problems, and feedback control with fault rejection problems are formulated/considered, mainly from a fault modeling point of view. The method is illustrated on a servo example including......A general architecture for fault tolerant control is proposed. The architecture is based on the (primary) YJBK parameterization of all stabilizing compensators and uses the dual YJBK parameterization to quantify the performance of the fault tolerant system. The approach suggested can be applied...

  4. Enhanced fault-tolerant quantum computing in d-level systems.

    Science.gov (United States)

    Campbell, Earl T

    2014-12-01

    Error-correcting codes protect quantum information and form the basis of fault-tolerant quantum computing. Leading proposals for fault-tolerant quantum computation require codes with an exceedingly rare property, a transversal non-Clifford gate. Codes with the desired property are presented for d-level qudit systems with prime d. The codes use n=d-1 qudits and can detect up to ∼d/3 errors. We quantify the performance of these codes for one approach to quantum computation known as magic-state distillation. Unlike prior work, we find performance is always enhanced by increasing d.

  5. Energy/Reliability Trade-offs in Fault-Tolerant Event-Triggered Distributed Embedded Systems

    DEFF Research Database (Denmark)

    Gan, Junhe; Gruian, Flavius; Pop, Paul;

    2011-01-01

    This paper presents an approach to the synthesis of low-power fault-tolerant hard real-time applications mapped on distributed heterogeneous embedded systems. Our synthesis approach decides the mapping of tasks to processing elements, as well as the voltage and frequency levels for executing each...

  6. Cost and benefits design optimization model for fault tolerant flight control systems

    Science.gov (United States)

    Rose, J.

    1982-01-01

    Requirements and specifications for a method of optimizing the design of fault-tolerant flight control systems are provided. Algorithms that could be used for developing new and modifying existing computer programs are also provided, with recommendations for follow-on work.

  7. Robust Fault Tolerant Control for a Class of Time-Delay Systems with Multiple Disturbances

    Directory of Open Access Journals (Sweden)

    Songyin Cao

    2013-01-01

    Full Text Available A robust fault tolerant control (FTC approach is addressed for a class of nonlinear systems with time delay, actuator faults, and multiple disturbances. The first part of the multiple disturbances is supposed to be an uncertain modeled disturbance and the second one represents a norm-bounded variable. First, a composite observer is designed to estimate the uncertain modeled disturbance and actuator fault simultaneously. Then, an FTC strategy consisting of disturbance observer based control (DOBC, fault accommodation, and a mixed H2/H∞ controller is constructed to reconfigure the considered systems with disturbance rejection and attenuation performance. Finally, simulations for a flight control system are given to show the efficiency of the proposed approach.

  8. Safety verification of a fault tolerant reconfigurable autonomous goal-based robotic control system

    OpenAIRE

    Braman, Julia M. B.; Murray, Richard M.; Wagner, David A.

    2007-01-01

    Fault tolerance and safety verification of control systems are essential for the success of autonomous robotic systems. A control architecture called Mission Data System (MDS), developed at the Jet Propulsion Laboratory, takes a goal-based control approach. In this paper, a method for converting goal network control programs into linear hybrid systems is developed. The linear hybrid system can then be verified for safety in the presence of failures using existing symbo...

  9. Distributed Fault-Tolerant Avionic Systems - A Real-Time Perspective

    CERN Document Server

    Burke, Michael

    2010-01-01

    This paper examines the problem of introducing advanced forms of fault-tolerance via reconfiguration into safety-critical avionic systems. This is required to enable increased availability after fault occurrence in distributed integrated avionic systems(compared to static federated systems). The approach taken is to identify a migration path from current architectures to those that incorporate re-configuration to a lesser or greater degree. Other challenges identified include change of the development process; incremental and flexible timing and safety analyses; configurable kernels applicable for safety-critical systems.

  10. An Efficient Fault Tolerance System Design for Cmos/Nanodevice Digital Memories

    Directory of Open Access Journals (Sweden)

    D. Kavitha

    2014-11-01

    Full Text Available Targeting on the future fault-prone hybrid CMOS/Nanodevice digital memories, this paper present two faulttolerance design approaches the integrally address the tolerance for defect and transient faults. These two approaches share several key features, including the use of a group of Bose-Chaudhuri- Hocquenghem (BCH codes for both defect tolerance and transient fault tolerance, and integration of BCH code selection and dynamic logical-to-physical address mapping. Thus, a new model of BCH decoder is proposed to reduce the area and simplify the computational scheduling of both syndrome and chien search blocks without parallelism leading to high throughput.The goal of fault tolerant computing is improve the dependability of systems where dependability can be defined as the ability of a system to deliver service at an acceptable level of confidence in either presence or absence falult.ss The results of the simulation and implementation using Xilinx ISE software and the LCD screen on the FPGA’s Board will be shown at last.

  11. Diagnosis and Tolerant Strategy of an Open-Switch Fault for T-type Three-Level Inverter Systems

    DEFF Research Database (Denmark)

    Choi, Uimin; Lee, Kyo Beum; Blaabjerg, Frede

    2014-01-01

    -tolerant strategy is explained by dividing into two cases: the faulty condition of half-bridge switches and the neutral-point switches. The performance of the T-type inverter system improves considerably by the proposed fault tolerant algorithm when a switch fails. The roposed method does not require additional......This paper proposes a new diagnosis method of an open-switch fault and fault-tolerant control strategy for T-type three-level inverter systems. The location of faulty switch can be identified by the average of normalized phase current and the change of the neutral-point voltage. The proposed fault...

  12. Adaptive Fault-Tolerant Control of Uncertain Nonlinear Large-Scale Systems With Unknown Dead Zone.

    Science.gov (United States)

    Chen, Mou; Tao, Gang

    2016-08-01

    In this paper, an adaptive neural fault-tolerant control scheme is proposed and analyzed for a class of uncertain nonlinear large-scale systems with unknown dead zone and external disturbances. To tackle the unknown nonlinear interaction functions in the large-scale system, the radial basis function neural network (RBFNN) is employed to approximate them. To further handle the unknown approximation errors and the effects of the unknown dead zone and external disturbances, integrated as the compounded disturbances, the corresponding disturbance observers are developed for their estimations. Based on the outputs of the RBFNN and the disturbance observer, the adaptive neural fault-tolerant control scheme is designed for uncertain nonlinear large-scale systems by using a decentralized backstepping technique. The closed-loop stability of the adaptive control system is rigorously proved via Lyapunov analysis and the satisfactory tracking performance is achieved under the integrated effects of unknown dead zone, actuator fault, and unknown external disturbances. Simulation results of a mass-spring-damper system are given to illustrate the effectiveness of the proposed adaptive neural fault-tolerant control scheme for uncertain nonlinear large-scale systems. PMID:26340792

  13. Fault-Tolerant Heat Exchanger

    Science.gov (United States)

    Izenson, Michael G.; Crowley, Christopher J.

    2005-01-01

    A compact, lightweight heat exchanger has been designed to be fault-tolerant in the sense that a single-point leak would not cause mixing of heat-transfer fluids. This particular heat exchanger is intended to be part of the temperature-regulation system for habitable modules of the International Space Station and to function with water and ammonia as the heat-transfer fluids. The basic fault-tolerant design is adaptable to other heat-transfer fluids and heat exchangers for applications in which mixing of heat-transfer fluids would pose toxic, explosive, or other hazards: Examples could include fuel/air heat exchangers for thermal management on aircraft, process heat exchangers in the cryogenic industry, and heat exchangers used in chemical processing. The reason this heat exchanger can tolerate a single-point leak is that the heat-transfer fluids are everywhere separated by a vented volume and at least two seals. The combination of fault tolerance, compactness, and light weight is implemented in a unique heat-exchanger core configuration: Each fluid passage is entirely surrounded by a vented region bridged by solid structures through which heat is conducted between the fluids. Precise, proprietary fabrication techniques make it possible to manufacture the vented regions and heat-conducting structures with very small dimensions to obtain a very large coefficient of heat transfer between the two fluids. A large heat-transfer coefficient favors compact design by making it possible to use a relatively small core for a given heat-transfer rate. Calculations and experiments have shown that in most respects, the fault-tolerant heat exchanger can be expected to equal or exceed the performance of the non-fault-tolerant heat exchanger that it is intended to supplant (see table). The only significant disadvantages are a slight weight penalty and a small decrease in the mass-specific heat transfer.

  14. A Systematic Approach to Sensitivity Analysis of Fault Tolerant Systems in NMR Architecture

    Directory of Open Access Journals (Sweden)

    Kourosh Aslansefat

    2015-01-01

    Full Text Available A fault tree illustrates the ways through which a system fails. It states different ways in which combination of faulty components result in an undesired event in the system. Being used in phases such as designing and exploiting industrial systems, and the designers able to evaluate the dependability attributes such as reliability, MTTF and sensitivity. In addition, in the mentioned ability, the fault tree is a systematic method for finding systems bottlenecks and weakness point. In spite of its extensive use in evaluating the reliability of systems, fault tree is rarely used in calculating sensitivity. In the last decade, few researches has been conducted in this field, however these methods are not applicable to large scale systems and are not systematic. This paper provides a systematic method for evaluating system sensitivity through fault tree. Then, it introduces sensitivity of NMR architecture as one of the common structures of fault tolerance which is used for enhancing systems’ reliability, safety and availability in industry. This article presents a comprehensive and parameterized formula for NMR structure's sensitivity. The presented method can be a great help for designing and exploiting reliable systems engineers in systematic and instant calculation of sensitivity by means of fault tree.

  15. Fault Tolerance Mobile Agent System Using Witness Agent in 2-Dimensional Mesh Network

    Directory of Open Access Journals (Sweden)

    Ahmad Rostami

    2010-09-01

    Full Text Available Mobile agents are computer programs that act autonomously on behalf of a user or its owner and travel through a network of heterogeneous machines. Fault tolerance is important in their itinerary. In this paper, existent methods of fault tolerance in mobile agents are described which they are considered in linear network topology. In the methods three agents are used to fault tolerance by cooperating to each others for detecting and recovering server and agent failure. Three types of agents are: actual agent which performs programs for its owner, witness agent which monitors the actual agent and the witness agent after itself, probe which is sent for recovery the actual agent or the witness agent on the side of the witness agent. Communication mechanism in the methods is message passing between these agents. The methods are considered in linear network. We introduce our witness agent approach for fault tolerance mobile agent systems in Two Dimensional Mesh (2D-Mesh Network. Indeed Our approach minimizes Witness-Dependency in this network and then represents its algorithm.

  16. Modeling and Design of Fault-Tolerant and Self-Adaptive Reconfigurable Networked Embedded Systems

    Directory of Open Access Journals (Sweden)

    Jürgen Teich

    2006-06-01

    Full Text Available Automotive, avionic, or body-area networks are systems that consist of several communicating control units specialized for certain purposes. Typically, different constraints regarding fault tolerance, availability and also flexibility are imposed on these systems. In this article, we will present a novel framework for increasing fault tolerance and flexibility by solving the problem of hardware/software codesign online. Based on field-programmable gate arrays (FPGAs in combination with CPUs, we allow migrating tasks implemented in hardware or software from one node to another. Moreover, if not enough hardware/software resources are available, the migration of functionality from hardware to software or vice versa is provided. Supporting such flexibility through services integrated in a distributed operating system for networked embedded systems is a substantial step towards self-adaptive systems. Beside the formal definition of methods and concepts, we describe in detail a first implementation of a reconfigurable networked embedded system running automotive applications.

  17. Modeling and Design of Fault-Tolerant and Self-Adaptive Reconfigurable Networked Embedded Systems

    Directory of Open Access Journals (Sweden)

    Streichert Thilo

    2006-01-01

    Full Text Available Automotive, avionic, or body-area networks are systems that consist of several communicating control units specialized for certain purposes. Typically, different constraints regarding fault tolerance, availability and also flexibility are imposed on these systems. In this article, we will present a novel framework for increasing fault tolerance and flexibility by solving the problem of hardware/software codesign online. Based on field-programmable gate arrays (FPGAs in combination with CPUs, we allow migrating tasks implemented in hardware or software from one node to another. Moreover, if not enough hardware/software resources are available, the migration of functionality from hardware to software or vice versa is provided. Supporting such flexibility through services integrated in a distributed operating system for networked embedded systems is a substantial step towards self-adaptive systems. Beside the formal definition of methods and concepts, we describe in detail a first implementation of a reconfigurable networked embedded system running automotive applications.

  18. Problems related to the integration of fault tolerant aircraft electronic systems

    Science.gov (United States)

    Bannister, J. A.; Adlakha, V.; Triyedi, K.; Alspaugh, T. A., Jr.

    1982-01-01

    Problems related to the design of the hardware for an integrated aircraft electronic system are considered. Taxonomies of concurrent systems are reviewed and a new taxonomy is proposed. An informal methodology intended to identify feasible regions of the taxonomic design space is described. Specific tools are recommended for use in the methodology. Based on the methodology, a preliminary strawman integrated fault tolerant aircraft electronic system is proposed. Next, problems related to the programming and control of inegrated aircraft electronic systems are discussed. Issues of system resource management, including the scheduling and allocation of real time periodic tasks in a multiprocessor environment, are treated in detail. The role of software design in integrated fault tolerant aircraft electronic systems is discussed. Conclusions and recommendations for further work are included.

  19. To err is robotic, to tolerate immunological: fault detection in multirobot systems.

    Science.gov (United States)

    Tarapore, Danesh; Lima, Pedro U; Carneiro, Jorge; Christensen, Anders Lyhne

    2015-01-01

    Fault detection and fault tolerance represent two of the most important and largely unsolved issues in the field of multirobot systems (MRS). Efficient, long-term operation requires an accurate, timely detection, and accommodation of abnormally behaving robots. Most existing approaches to fault-tolerance prescribe a characterization of normal robot behaviours, and train a model to recognize these behaviours. Behaviours unrecognized by the model are consequently labelled abnormal or faulty. MRS employing these models do not transition well to scenarios involving temporal variations in behaviour (e.g., online learning of new behaviours, or in response to environment perturbations). The vertebrate immune system is a complex distributed system capable of learning to tolerate the organism's tissues even when they change during puberty or metamorphosis, and to mount specific responses to invading pathogens, all without the need of a genetically hardwired characterization of normality. We present a generic abnormality detection approach based on a model of the adaptive immune system, and evaluate the approach in a swarm of robots. Our results reveal the robust detection of abnormal robots simulating common electro-mechanical and software faults, irrespective of temporal changes in swarm behaviour. Abnormality detection is shown to be scalable in terms of the number of robots in the swarm, and in terms of the size of the behaviour classification space. PMID:25642825

  20. Synthesis of Fault-Tolerant Schedules with Transparency/Performance Trade-offs for Distributed Embedded Systems

    DEFF Research Database (Denmark)

    Izosimov, Viacheslav; Pop, Paul; Eles, Petru;

    2006-01-01

    In this paper we present an approach to the scheduling of fault-tolerant embedded systems for safety-critical applications. Processes and messages are statically scheduled, and we use process re-execution for recovering from multiple transient faults. If process recovery is performed such that th...... process graph, where the fault occurrence information is represented as conditional edges and the transparent recovery is captured using synchronization nodes.......In this paper we present an approach to the scheduling of fault-tolerant embedded systems for safety-critical applications. Processes and messages are statically scheduled, and we use process re-execution for recovering from multiple transient faults. If process recovery is performed...... such that the operation of other processes is not affected, we call it transparent recovery. Although transparent recovery has the advantages of fault containment, improved debugability and less memory needed to store the fault-tolerant schedules, it will introduce delays that can violate the timing constraints...

  1. Fault tolerant control for unstable systems: A linear time varying approach

    DEFF Research Database (Denmark)

    Stoustrup, Jakob; Niemann, Hans Henrik

    2004-01-01

    corresponding to the occurrence of various faults are simultaneously stabilizable by a linear, time-invariant compensator, this compensator might have to be of very high order, as shown in a recent publication. In this paper, we propose a design procedure for a timevarying compensator, which overcomes......In (passive) fault tolerant control design, the objective is to find a fixed compensator, which will maintain a suitable performance - or at least stability - in the event that a fault should occur. A major theoretical obstacle to obtain this objective, is that even if the system models...... the obstacle for any finite number of faults with a controller order of no more than the plant order. The performance of this compensator might be poor, but a heuristic procedure for improving the performance is also shown, and an example demonstrates that this improvement can be truly significant....

  2. An adaptive fuzzy design for fault-tolerant control of MIMO nonlinear uncertain systems

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    This paper presents a novel control method for accommodating actuator faults in a class of multiple-input multiple-output (MIMO) nonlinear uncertain systems.The designed control scheme can tolerate both the time-varying lock-in-place and loss of effectiveness actuator faults.In each subsystem of the considered MIMO system,the controller is obtained from a backstepping procedure;an adaptive fuzzy approximator with minimal learning parameterization is employed to approximate the package of unknown nonlinear f...

  3. Fault-tolerant control of linear uncertain systems using H∞ robust predictive control

    Institute of Scientific and Technical Information of China (English)

    Chen Xueqin; Geng Yunhai; Zhang Yingchun; Wang Feng

    2008-01-01

    The robust fault-tolerant control problem of linear uncertain systems is studied. It is shown that a solution for this problem can be obtained from a H∞ robust predictive controller (RMPC) by the method of linear matrix inequality (LMI). This approach has the advantages of both H∞ control and MPC: the robustness and ability to handle constraints explicitly. The robust closed-loop stability of the linear uncertain system with input and output constraints is proven under an actuator and sensor faults condition. Finally, satisfactory results of simulation experiments verify the validity of this algorithm.

  4. Observer-based fault-tolerant control for a class of nonlinear networked control systems

    Science.gov (United States)

    Mahmoud, M. S.; Memon, A. M.; Shi, Peng

    2014-08-01

    This paper presents a fault-tolerant control (FTC) scheme for nonlinear systems which are connected in a networked control system. The nonlinear system is first transformed into two subsystems such that the unobservable part is affected by a fault and the observable part is unaffected. An observer is then designed which gives state estimates using a Luenberger observer and also estimates unknown parameter of the system; this helps in fault estimation. The FTC is applied in the presence of sampling due to the presence of a network in the loop. The controller gain is obtained using linear-quadratic regulator technique. The methodology is applied on a mechatronic system and the results show satisfactory performance.

  5. Fault detection and fault-tolerant control using sliding modes

    CERN Document Server

    Alwi, Halim; Tan, Chee Pin

    2011-01-01

    ""Fault Detection and Fault-tolerant Control Using Sliding Modes"" is the first text dedicated to showing the latest developments in the use of sliding-mode concepts for fault detection and isolation (FDI) and fault-tolerant control in dynamical engineering systems. It begins with an introduction to the basic concepts of sliding modes to provide a background to the field. This is followed by chapters that describe the use and design of sliding-mode observers for FDI using robust fault reconstruction. The development of a class of sliding-mode observers is described from first principles throug

  6. Robust H-infinity fault-tolerant control for uncertain descriptor systems by dynamical compensators

    Institute of Scientific and Technical Information of China (English)

    Bing LIANG; Guangren DUAN

    2004-01-01

    The problem of robust H-infinity fault-tolerant control against sensor failures for a class of uncertain descriptor systems via dynamical compensators is considered.Based on H-infinity theory in descriptor systems,a sufficient condition for the existence of dynamical compensators with H-infinity fault-tolerant function is derived and expressions for the gain matrices in the compensators are presented.The dynamical compensator guarantees that the resultant colsed-loop system is admissible;furthermore,it maintains certain H-infinity norm performance in the normal condition as well as in the event of sensor failures and parameter uncertainties.A numerical example shows the effect of the proposed method.

  7. Adaptive fault-tolerant control of linear time-invariant systems in the presence of actuator saturation

    Institute of Scientific and Technical Information of China (English)

    Wei GUAN; Guanghong YANG

    2009-01-01

    This paper studies the problem of designing adaptive fault-tolerant controllers for linear time-invariant systems with actuator saturation.New methods for designing indirect adaptive fault-tolerant controllers via state feedback are presented for actuator fault compensations.Based on the on-line estimation of eventual faults,the adaptive fault-tolerant controller parameters are updating automatically to compensate the fault effects on systems.The designs are developed in the framework of linear matrix inequality (LMI) approach,which can enlarge the domain of attraction of closed-loop systems in the cases of actuator saturation and actuator failures.Two examples are given to illustrate the effectiveness of the design method.

  8. Feasibility analysis and design of a fault tolerant computing system: a TMR microprocessor system design of 64-Bit COTS microprocessors

    OpenAIRE

    Eken, Huseyin Baha

    2001-01-01

    The purpose of this thesis is to analyze and determine the feasibility of implementing a fault tolerant computing system that is able to function in the presence of radiation induced Single Event Upsets (SEU) by using the Triple Modular Redundancy (TMR) technique with 64-bit Commercial-Off-The- Shelf (COTS) microprocessors. Due to the radiation environment in space, electronic devices must be designed to tolerate the radiation effects. While there are radiation-hardened devices that can toler...

  9. Fault-tolerant supervisory control of VAV air-conditioning systems

    Energy Technology Data Exchange (ETDEWEB)

    Liu, X.-F.; Dexter, A. [Department of Engineering Science, University of Oxford, Oxford (United Kingdom)

    2001-07-01

    The paper describes a supervisory control scheme that adapts to the presence of degradation faults and minimises any resulting increase in energy consumption or deterioration in occupant comfort. Since there is a high degree of uncertainty associated with the results of any fault identification scheme in information-poor systems of this type, the supervisory control scheme uses fuzzy models to predict the control performance and a computationally undemanding optimisation scheme to determine the most appropriate set-points. The fault-tolerant control scheme is developed and evaluated using a detailed computer simulation of a multi-zone, variable-air-volume (VAV), air-conditioning system. The fuzzy models relate the performance of the terminal-boxes, the air-handling unit and the chiller to fuzzy descriptions of the cooling load, the supply air and chilled water temperature set-points, and the amount of air-side and water-side fouling. Results are presented that demonstrate the ability of the fuzzy models to predict the performance and show how the power consumption of the air-conditioning system varies with set-point changes and the presence of both water-side and air-side fouling. The main factors that determine the suitability of a particular air-conditioning system for fault-tolerant control are also discussed. (author)

  10. Fuxi: A fault-tolerant resource management and job scheduling system at internet scale

    OpenAIRE

    Zhang, Z; C. Li; Tao, Y; Yang, R; H. Tang; Xu, J.

    2014-01-01

    Scalability and fault-tolerance are two fundamental challenges for all distributed computing at Internet scale. Despite many recent advances from both academia and industry, these two problems are still far from settled. In this paper, we present Fuxi, a resource management and job scheduling system that is capable of handling the kind of workload at Alibaba where hundreds of terabytes of data are generated and analyzed everyday to help optimize the company's business operations and user expe...

  11. A metaobject architecture for fault-tolerant distributed systems : the FRIENDS approach

    OpenAIRE

    Fabre, Jean-Charles; Pérennou, Tanguy

    1998-01-01

    The FRIENDS system developed at LAAS-CNRS is a metalevel architecture providing libraries of metaobjects for fault tolerance, secure communication, and group-based distributed applications. The use of metaobjects provides a nice separation of concerns between mechanisms and applications. Metaobjects can be used transparently by applications and can be composed according to the needs of a given application, a given architecture, and its underlying properties. In FRIENDS, metaobjects are use...

  12. Ship Propulsion System as a Benchmark for Fault-Tolerant Control

    DEFF Research Database (Denmark)

    Izadi-Zamanabadi, Roozbeh; Blanke, M.

    1998-01-01

    -tolerant control is a fairly new area. The paper presents a ship propulsion system as a benchmark that should be useful as a platform for development of new ideas and comparison of methods. The benchmark has two main elements. One is development of efficient FDI algorithms, the other is analysis and implementation...... of autonomous fault accommodation. A benchmark kit can be obtained from the authors....

  13. Advanced information processing system: The Army Fault-Tolerant Architecture detailed design overview

    Science.gov (United States)

    Harper, Richard E.; Babikyan, Carol A.; Butler, Bryan P.; Clasen, Robert J.; Harris, Chris H.; Lala, Jaynarayan H.; Masotto, Thomas K.; Nagle, Gail A.; Prizant, Mark J.; Treadwell, Steven

    1994-01-01

    The Army Avionics Research and Development Activity (AVRADA) is pursuing programs that would enable effective and efficient management of large amounts of situational data that occurs during tactical rotorcraft missions. The Computer Aided Low Altitude Night Helicopter Flight Program has identified automated Terrain Following/Terrain Avoidance, Nap of the Earth (TF/TA, NOE) operation as key enabling technology for advanced tactical rotorcraft to enhance mission survivability and mission effectiveness. The processing of critical information at low altitudes with short reaction times is life-critical and mission-critical necessitating an ultra-reliable/high throughput computing platform for dependable service for flight control, fusion of sensor data, route planning, near-field/far-field navigation, and obstacle avoidance operations. To address these needs the Army Fault Tolerant Architecture (AFTA) is being designed and developed. This computer system is based upon the Fault Tolerant Parallel Processor (FTPP) developed by Charles Stark Draper Labs (CSDL). AFTA is hard real-time, Byzantine, fault-tolerant parallel processor which is programmed in the ADA language. This document describes the results of the Detailed Design (Phase 2 and 3 of a 3-year project) of the AFTA development. This document contains detailed descriptions of the program objectives, the TF/TA NOE application requirements, architecture, hardware design, operating systems design, systems performance measurements and analytical models.

  14. Fault-Tolerant Onboard Monitoring and Decision Support Systems

    DEFF Research Database (Denmark)

    Lajic, Zoran

    The purpose of this research project is to improve current onboard decision support systems. Special focus is on the onboard prediction of the instantaneous sea state. In this project a new approach to increasing the overall reliability of a monitoring and decision support system has been...

  15. Service for fault tolerance in the Ad Hoc Networks based on Multi Agent Systems

    Directory of Open Access Journals (Sweden)

    Ghalem Belalem

    2011-02-01

    Full Text Available The Ad hoc networks are distributed networks, self-organized and does not require infrastructure. In such network, mobile infrastructures are subject of disconnections. This situation may concern a voluntary or involuntary disconnection of nodes caused by the high mobility in the Ad hoc network. In these problems we are trying through this work to contribute to solving these problems in order to ensure continuous service by proposing our service for faults tolerance based on Multi Agent Systems (MAS, which predict a problem and decision making in relation to critical nodes. Our work contributes to study the prediction of voluntary and involuntary disconnections in the Ad hoc network; therefore we propose our service for faults tolerance that allows for effective distribution of information in the Network by selecting some objects of the network to be duplicates of information.

  16. Fault-Tolerant Scheduling for Real-Time Embedded Control Systems

    Institute of Scientific and Technical Information of China (English)

    Chun-Hua Yang; Geert Deconinck; Wei-Hua Gui

    2004-01-01

    With the increasing complexity of industrial application, an embedded control system (ECS) requires processing a number of hard real-time tasks and needs fault-tolerance to assure high reliability. Considering the characteristics of real-time tasks in ECS, an integrated algorithm is proposed to schedule real-time tasks and to guarantee that all real-time tasks are completed before their deadlines even in the presence of faults. Based on the nonpreemptive critical-section protocol (NCSP), this paper analyzes the blocking time introduced by resource conflicts of relevancy tasks in fault-tolerant multiprocessor systems. An extended schedulability condition is presented to check the assignment feasibility of a given task to a processor. A primary/backup approach and on-line replacement of failed processors are used to tolerate processor failures. The analysis reveals that the integrated algorithm bounds the blocking time, requires limited overhead on the number of processors, and still assures good processor utilization. This is also demonstrated by simulation results. Both analysis and simulation show the effectiveness of the proposed algorithm in ECS.

  17. Synthesis of Fault-Tolerant Embedded Systems with Checkpointing and Replication

    DEFF Research Database (Denmark)

    Izosimov, Viacheslav; Pop, Paul; Eles, Petru;

    2006-01-01

    -triggered protocol. Our synthesis approach decides the assignment of fault-tolerance policies to processes, the optimal placement of checkpoints and the mapping of processes to processors such that transient faults are tolerated and the timing constraints of the application are satisfied. We present several...

  18. Fault-tolerant Agreement in Synchronous Message-passing Systems

    CERN Document Server

    Raynal, Michel

    2010-01-01

    The present book focuses on the way to cope with the uncertainty created by process failures (crash, omission failures and Byzantine behavior) in synchronous message-passing systems (i.e., systems whose progress is governed by the passage of time). To that end, the book considers fundamental problems that distributed synchronous processes have to solve. These fundamental problems concern agreement among processes (if processes are unable to agree in one way or another in presence of failures, no non-trivial problem can be solved). They are consensus, interactive consistency, k-set agreement an

  19. Optimal maintenance center inventories for fault-tolerant repairable systems

    Science.gov (United States)

    Lawrence, S. H.; Schaefer, M. K.

    1984-01-01

    A probabilistic approach is taken to determine the optimal repairable parts inventory for a maintenance center, servicing machines which contain several m-out-of-n systems of different parts, with a constraint on the total inventory investment. A model, based on the discrete Markov process, accounts for a typical ultrareliable avionics system, such as one presently being developed by NASA. The dynamic programming algorithm for minimizing the stockout and holding costs is applied to an exemplary maintenance center, and solutions for single-item and multi-item cases are given. The computational burden is noted to be reasonable and a computer program is used to generate optimal solutions.

  20. Fault tolerant PLC system using CPU and I/O redundancy with switch over logic system for nuclear instrumentation

    International Nuclear Information System (INIS)

    Nuclear instrumentation in power plants and fuel reprocessing plants demand very high reliable fault tolerant programmable logic controllers (PLC) since it is directly related to hazardous operation involving safety of plant, operator and in turn public at large. Components of control systems can fail depending on the circumstances and level of preparedness in plants, leading to a minor or major disaster. Utilizing existing technology and configuring system architecture, a fault tolerant PLC can provide superior solution to meet some of the challenges like high reliability, integrity and availability. This paper presents the background, concepts and implementation of fault tolerant PLC architecture using CPU and I/O redundancy with switch over logic system for nuclear instrumentation. (author)

  1. A Ship Propulsion System Model for Fault-tolerant Control

    DEFF Research Database (Denmark)

    Izadi-Zamanabadi, Roozbeh; Blanke, M.

    . The propulsion system model is presented in two versions: the first one consists of one engine and one propeller, and the othe one consists of two engines and their corresponding propellers placed in parallel in the ship. The corresponding programs are developed and are available....

  2. Task Migration for Fault-Tolerance in Mixed-Criticality Embedded Systems

    DEFF Research Database (Denmark)

    Saraswat, Prabhat Kumar; Pop, Paul; Madsen, Jan

    2009-01-01

    In this paper we are interested in mixed-criticality embedded applications implemented on distributed architectures. Depending on their time-criticality, tasks can be hard or soft real-time and regarding safety-criticality, tasks can be fault-tolerant to transient faults, permanent faults, or have...

  3. Plan for the Characterization of HIRF Effects on a Fault-Tolerant Computer Communication System

    Science.gov (United States)

    Torres-Pomales, Wilfredo; Malekpour, Mahyar R.; Miner, Paul S.; Koppen, Sandra V.

    2008-01-01

    This report presents the plan for the characterization of the effects of high intensity radiated fields on a prototype implementation of a fault-tolerant data communication system. Various configurations of the communication system will be tested. The prototype system is implemented using off-the-shelf devices. The system will be tested in a closed-loop configuration with extensive real-time monitoring. This test is intended to generate data suitable for the design of avionics health management systems, as well as redundancy management mechanisms and policies for robust distributed processing architectures.

  4. Fault-tolerant quantum computation -- a dynamical systems approach

    CERN Document Server

    Fern, J; Simic, S; Sastry, S; Fern, Jesse; Kempe, Julia; Simic, Slobodan; Sastry, Shankar

    2004-01-01

    We apply a dynamical systems approach to concatenation of quantum error correcting codes, extending and generalizing the results of Rahn et al. [8] to both diagonal and nondiagonal channels. Our point of view is global: instead of focusing on particular types of noise channels, we study the geometry of the coding map as a discrete-time dynamical system on the entire space of noise channels. In the case of diagonal channels, we show that any code with distance at least three corrects (in the infinite concatenation limit) an open set of errors. For CSS codes, we give a more precise characterization of that set. We show how to incorporate noise in the gates, thus completing the framework. We derive some general bounds for noise channels, which allows us to analyze several codes in detail.

  5. Fault Tolerant Neural Network for ECG Signal Classification Systems

    Directory of Open Access Journals (Sweden)

    MERAH, M.

    2011-08-01

    Full Text Available The aim of this paper is to apply a new robust hardware Artificial Neural Network (ANN for ECG classification systems. This ANN includes a penalization criterion which makes the performances in terms of robustness. Specifically, in this method, the ANN weights are normalized using the auto-prune method. Simulations performed on the MIT ? BIH ECG signals, have shown that significant robustness improvements are obtained regarding potential hardware artificial neuron failures. Moreover, we show that the proposed design achieves better generalization performances, compared to the standard back-propagation algorithm.

  6. Diagnosis and Fault-tolerant Control, 3rd Edition

    OpenAIRE

    Blanke, Mogens; Kinnaert, Michel; Lunze, Jan; Staroswiecki, Marcel

    2015-01-01

    The book presents effective model-based analysis and design methods for fault diagnosis and fault-tolerant control. Architectural and structural models are used to analyse the propagation of the fault through the process, to test the fault detectability and to find the redundancies in the process that can be used to ensure fault tolerance. It also introduces design methods suitable for diagnostic systems and fault-tolerant controllers for continuous processes that are described by analytical ...

  7. Research on fault-tolerant control of networked control systems based on information scheduling

    Institute of Scientific and Technical Information of China (English)

    Huo Zhihong; Zhang Zhixue; Fang Huajing

    2008-01-01

    A kind of networked control system is studied; the networked control system with noise disturbance is modeled based on information scheduling and control co-design.Augmented state matrix analysis method is introduced,and robust fault-tolerant control problem of networked control systems with noise disturbance under actuator failures is studied.The parametric expression of the controller under actuator failures is given.Furthermore,the result is analyzed by simulation tests,which not only satisfies the networked control systems stability,but also decreases the data information number in network channel and makes full use of the network resources.

  8. Research on robust fault-tolerant control for networked control system with packet dropout

    Institute of Scientific and Technical Information of China (English)

    Huo Zhihong; Fang Huajing

    2007-01-01

    A kind of networked control system with network-induced delay and packet dropout, modeled on asynchronous dynamical systems was tested, and the integrity design of the networked control system with sensors failures and actuators failures was analyzed using hybrid systems technique based on the robust fault-tolerant control theory. The parametric expression of controller is given based on the feasible solution of linear matrix inequality. The simulation results are provided on the basis of detailed theoretical analysis, which further demonstrate the validity of the proposed schema.

  9. Reliability model of fault-tolerant data processing system with primary and backup nodes

    Science.gov (United States)

    Rahman, P. A.; Bobkova, E. Yu

    2016-04-01

    This paper deals with the fault-tolerant data processing systems, which are widely used in modern world of information technologies and have acceptable overhead expenses in hardware implementation. A simplified reliability model for duplex systems and the offered by authors advanced model for data processing systems with primary and backup nodes based on a three-state model of recoverable elements, which takes into consideration different failure rates of passive and active nodes and finite time of node activation, are also given. A calculation formula for the availability factor of the dual-node data processing system with primary and backup nodes and calculation examples are also provided.

  10. (m,n-Semirings and a Generalized Fault-Tolerance Algebra of Systems

    Directory of Open Access Journals (Sweden)

    Syed Eqbal Alam

    2013-01-01

    Full Text Available We propose a new class of mathematical structures called (m,n-semirings (which generalize the usual semirings and describe their basic properties. We define partial ordering and generalize the concepts of congruence, homomorphism, and so forth, for (m,n-semirings. Following earlier work by Rao (2008, we consider systems made up of several components whose failures may cause them to fail and represent the set of such systems algebraically as an (m,n-semiring. Based on the characteristics of these components, we present a formalism to compare the fault-tolerance behavior of two systems using our framework of a partially ordered (m,n-semiring.

  11. Fault-tolerant control of delta operator systems with actuator saturation and effectiveness loss

    Science.gov (United States)

    Yang, Hongjiu; Zhang, Luyang; Zhao, Ling; Yuan, Yuan

    2016-07-01

    This paper studies the problem of robust fault-tolerant control against the actuator effectiveness loss for delta operator systems with actuator saturation. Ellipsoids are used to estimate the domain of attraction for the delta operator systems with actuator saturation and effectiveness loss. Some invariance set conditions used for enlarging the domain of attraction are expressed by linear matrix inequalities. Discussions on system performance optimisation are presented in this paper, including reduction on computational complexity, expansion of the domain of attraction and disturbance rejection. Two numerical examples are given to illustrate the effectiveness of the developed techniques.

  12. MICROTHREAD BASED (MTB) COARSE GRAINED FAULT TOLERANCE SUPERSCALAR PROCESSOR ARCHITECTURE

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Fault tolerance in microprocessor systems has become a popular topic of architecture research.Much work has been done at different levels to accomplish reliability against soft errors, and some fault tolerance architectures have been proposed. But little attention is paid to the thread level superscalar fault tolerance.This letter introduces microthread concept into superscalar processor fault tolerance domain, and puts forward a novel fault tolerance architecture, namely, MicroThread Based (MTB) coarse grained transient fault tolerance superscalar processor architecture, then discusses some detailed implementations.

  13. Design and RAMS Analysis of a Fault-Tolerant Computer Control System

    Institute of Scientific and Technical Information of China (English)

    WANG Shuai; JI Yindong; DONG Wei; YANG Shiyuan

    2007-01-01

    This paper presents a fault-tolerant computer system. It is designed as a double 2-out-of-2 architecture based on component redundant technique. Also, a quantitative probabilistic model is presented for evaluating the reliability, availability, maintainability and safety (RAMS) of this architecture. Hierarchical modeling method and Markov modeling method are used in RAMS analysis to evaluate the system characteristics. The double 2-out-of-2 system is compared with the other two systems, all voting triple modular redundancy (AVTMR) system and dual-duplex system. According to the result, the double 2-out-of-2 system has the highest dependability. Especially, the system can satisfy the safety integrity level (SIL) 4, which means the system's probability of catastrophic failure less than or equal to 10~8 per hour, therefore, it can be applied to life critical systems such as high-speed railway systems.

  14. Investigation of the applicability of a functional programming model to fault-tolerant parallel processing for knowledge-based systems

    Science.gov (United States)

    Harper, Richard

    1989-01-01

    In a fault-tolerant parallel computer, a functional programming model can facilitate distributed checkpointing, error recovery, load balancing, and graceful degradation. Such a model has been implemented on the Draper Fault-Tolerant Parallel Processor (FTPP). When used in conjunction with the FTPP's fault detection and masking capabilities, this implementation results in a graceful degradation of system performance after faults. Three graceful degradation algorithms have been implemented and are presented. A user interface has been implemented which requires minimal cognitive overhead by the application programmer, masking such complexities as the system's redundancy, distributed nature, variable complement of processing resources, load balancing, fault occurrence and recovery. This user interface is described and its use demonstrated. The applicability of the functional programming style to the Activation Framework, a paradigm for intelligent systems, is then briefly described.

  15. Fault Tolerant Approach for Data Encryption and Digital Signature Based on ECC System

    Institute of Scientific and Technical Information of China (English)

    ZENG Yong; MA Jian-feng

    2005-01-01

    An integrated fault tolerant approach for data encryption and digital signature based on elliptic curve cryptography is proposed. This approach allows the receiver to verify the sender's identity and can simultaneously deal with error detection and data correction. Up to three errors in our approach can be detected and corrected. This approach has at least the same security as that based on RSA system, but smaller keys to achieve the same level of security. Our approach is more efficient than the known ones and more suited for limited environments like personal digital assistants (PDAs), mobile phones and smart cards without RSA co- processors.

  16. Fault Tolerant Wind Farm Control

    DEFF Research Database (Denmark)

    Odgaard, Peter Fogh; Stoustrup, Jakob

    2013-01-01

    with best at a wind turbine control level. However, some faults are better dealt with at the wind farm control level, if the wind turbine is located in a wind farm. In this paper a benchmark model for fault detection and isolation, and fault tolerant control of wind turbines implemented at the wind farm...... scenarios. This benchmark model is used in an international competition dealing with Wind Farm fault detection and isolation and fault tolerant control....... control level is presented. The benchmark model includes a small wind farm of nine wind turbines, based on simple models of the wind turbines as well as the wind and interactions between wind turbines in the wind farm. The model includes wind and power references scenarios as well as three relevant fault...

  17. A Concept for fault tolerant controllers

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik; Poulsen, Niels Kjølstad

    2009-01-01

    This paper describe a concept for fault tolerant controllers (FTC) based on the YJBK (after Youla, Jabr, Bongiorno and Kucera) parameterization. This controller architecture will allow to change the controller on-line in the case of faults in the system. In the described FTC concept, a safe mode...

  18. Filtering and fault tolerant control of parameter-varying time-delay systems and applications

    Science.gov (United States)

    Mohammadpour Velni, Javad

    This dissertation addresses some open problems in control systems theory. The problems considered include the dynamic controller and filter design for Linear Parameter Varying (LPV) time-delay systems, the reconfigurable control design in Fault Tolerant Control Systems (FTCS) and fault diagnostics in Diesel engines. In the first part of this thesis, we investigate the problem of designing parameter-dependent filters for output estimation of LPV time-delay systems. The filters are designed such that the filtering error system guarantees an optimum level of H2 or Hinfinity performance. A state-delay term is included in the filter dynamics to reduce the design conservatism and improve the performance. The Linear Matrix Inequality (LMI)-based synthesis conditions developed for the filter design purposes are categorized into the rate-dependent and delay-dependent conditions which could handle the time-varying state-delay and bounded small delay cases, respectively. Among these two, the latter one is shown to provide a significant reduction in the conservativeness in the filter design. The second part of the thesis examines the analysis and synthesis of Fault Tolerant Control (FTC) systems in an LPV framework. For reconfigurable control design purposes, the information from Fault Detection and Isolation (FDI) module, that provides an estimate of the fault parameters, is utilized to schedule the controller matrices. We will also present a formulation that incorporates the factor of detection delay in the FTC supervisory system. It is shown that including this delay in the synthesis conditions leads to improved performance and reduced control effort. For analysis of the FTC systems including time-delay, where the fault parameters might be identified inaccurately, we first introduce the notion of brief instability for LPV time-delay systems. In these systems it is possible that the output trajectory converges to zero even though there are parameter trajectories for which

  19. State of the art on fault-tolerant real time distributed systems

    International Nuclear Information System (INIS)

    The integration of new computerized functions in power plant, and especially nuclear power plant, control and instrumentation systems implies more and more stringent requirements as to communication system reliability. For if an item of equipment, or even a computer program, can be validated and qualified, no formal qualification procedure is presently imposed on communication networks. This is certainly due to the relative immaturity of these networks, but also to their complexity. It is for this reason that, in the context of preparation for the future PWR 2000 standardized nuclear plants, it would seem appropriate to take a look at fault-tolerant communication systems. Since C and I type applications (in the control room) are divided between several computers and are required to contend with extremely severe time constraints, EDF has undertaken investigation of fault-tolerant, real time distributed systems. This paper summarized the state of the art in the field as it appears from discussion with computer manufacturers, academics and research workers on related projects. The results obtained were then used to determine trends as to ''promising'' solutions. The paper concludes with recommended study programs for the PCC department of EDF/R and DD for the next few years. (author), 9 figs., 10 refs., 2 annexes

  20. Design Approach for Fault Recoverable ALU with Improved Fault Tolerance

    Directory of Open Access Journals (Sweden)

    Ankit K V

    2015-08-01

    Full Text Available A new design for fault tolerant and fault recoverable ALU System has been proposed in this paper. Reliability is one of the most critical factors that have to be considered during the designing phase of any IC. In critical applications like Medical equipment & Military applications this reliability factor plays a very critical role in determining the acceptance of product. Insertion of special modules in the main design for reliability enhancement will give considerable amount of area & power penalty. So, a novel approach to this problem is to find ways for reusing the already available components in digital system in efficient way to implement recoverable methodologies. Triple Modular Redundancy (TMR has traditionally used for protecting digital logic from the SEUs (single event upset by triplicating the critical components of the system to give fault tolerance to system. ScTMR- Scan chain-based error recovery TMR technique provides recovery for all internal faults. ScTMR uses a roll-forward approach and employs the scan chain implemented in the circuits for testability purposes to recover the system to fault-free state. The proposed design will incorporate a ScTMR controller over TMR system of ALU and will make the system fault tolerant and fault recoverable. Hence, proposed design will be more efficient & reliable to use in critical applications, than any other design present till today.

  1. Scheduling and Optimization of Fault-Tolerant Embedded Systems with Transparency/Performance Trade-Offs

    DEFF Research Database (Denmark)

    Izosimov, Viacheslav; Pop, Paul; Eles, Petru;

    2012-01-01

    In this article, we propose a strategy for the synthesis of fault-tolerant schedules and for the mapping of fault-tolerant applications. Our techniques handle transparency/performance trade-offs and use the faultoccurrence information to reduce the overhead due to fault tolerance. Processes...... and messages are statically scheduled, and we use process reexecution for recovering from multiple transient faults. We propose a finegrained transparent recovery, where the property of transparency can be selectively applied to processes and messages. Transparency hides the recovery actions in a selected part...... of the application so that they do not affect the schedule of other processes and messages. While leading to longer schedules, transparent recovery has the advantage of both improved debuggability and less memory needed to store the faulttolerant schedules....

  2. Fault-Tolerant Grid Architecture and Practice

    Institute of Scientific and Technical Information of China (English)

    JIN Hai(金海); ZOU DeQing(邹德清); CHEN HanHua(陈汉华); SUN JianHua(孙建华); WU Song(吴松)

    2003-01-01

    Grid computing emerges as effective technologies to couple geographically distributed resources and solve large-scale computational problems in wide area networks. The fault tolerance is a significant and complex issue in grid computing systems. Various techniques have been investigated to detect and correct faults in distributed computing systems. Unreliable fault detection is one of the most effective techniques. Globus as a grid middleware manages resources in a wide area network. The Globus fault detection service uses the well-known techniques based on unreliable fault detectors to detect and report component failures. However, more powerful techniques are required to detect and correct both system-level and application-level faults in a grid system, and a convenient toolkit is also needed to maintain the consistency in the grid. A fault-tolerant grid platform (FTGP) based on an unreliable fault detector and the Globus fault detection service is presented in this paper. The platform offers effective strategies in such three aspects as grid key components, user tasks, and high-level applications.

  3. A Fault-Tolerant Emergency-Aware Access Control Scheme for Cyber-Physical Systems

    CERN Document Server

    Wu, Guowei; Xia, Feng; Yao, Lin

    2012-01-01

    Access control is an issue of paramount importance in cyber-physical systems (CPS). In this paper, an access control scheme, namely FEAC, is presented for CPS. FEAC can not only provide the ability to control access to data in normal situations, but also adaptively assign emergency-role and permissions to specific subjects and inform subjects without explicit access requests to handle emergency situations in a proactive manner. In FEAC, emergency-group and emergency-dependency are introduced. Emergencies are processed in sequence within the group and in parallel among groups. A priority and dependency model called PD-AGM is used to select optimal response-action execution path aiming to eliminate all emergencies that occurred within the system. Fault-tolerant access control polices are used to address failure in emergency management. A case study of the hospital medical care application shows the effectiveness of FEAC.

  4. Low cost management of replicated data in fault-tolerant distributed systems

    Science.gov (United States)

    Joseph, Thomas A.; Birman, Kenneth P.

    1990-01-01

    Many distributed systems replicate data for fault tolerance or availability. In such systems, a logical update on a data item results in a physical update on a number of copies. The synchronization and communication required to keep the copies of replicated data consistent introduce a delay when operations are performed. A technique is described that relaxes the usual degree of synchronization, permitting replicated data items to be updated concurrently with other operations, while at the same time ensuring that correctness is not violated. The additional concurrency thus obtained results in better response time when performing operations on replicated data. How this technique performs in conjunction with a roll-back and a roll-forward failure recovery mechanism is also discussed.

  5. Fault Tolerant External Memory Algorithms

    DEFF Research Database (Denmark)

    Jørgensen, Allan Grønlund; Brodal, Gerth Stølting; Mølhave, Thomas

    2009-01-01

    Algorithms dealing with massive data sets are usually designed for I/O-efficiency, often captured by the I/O model by Aggarwal and Vitter. Another aspect of dealing with massive data is how to deal with memory faults, e.g. captured by the adversary based faulty memory RAM by Finocchi and Italiano....... However, current fault tolerant algorithms do not scale beyond the internal memory. In this paper we investigate for the first time the connection between I/O-efficiency in the I/O model and fault tolerance in the faulty memory RAM, and we assume that both memory and disk are unreliable. We show a lower...... bound on the number of I/Os required for any deterministic dictionary that is resilient to memory faults. We design a static and a dynamic deterministic dictionary with optimal query performance as well as an optimal sorting algorithm and an optimal priority queue. Finally, we consider scenarios where...

  6. Model-Based Fault Tolerant Control for Hybrid Dynamic Systems with Sensor Faults%一类带有传染器故障的混合系统的容错控制

    Institute of Scientific and Technical Information of China (English)

    杨浩; 冒泽慧; 姜斌

    2006-01-01

    A model-based fault tolerant control approach for hybrid linear dynamic systems is proposed in this paper. The proposed method, taking advantage of reliable control, can maintain the performance of the faulty system during the time delay of fault detection and diagnosis (FDD) and fault accommodation (FA), which can be regarded as the first line of defence against sensor faults.Simulation results of a three-tank system with sensor fault are given to show the efficiency of the method.

  7. GRID COMPUTING AND FAULT TOLERANCE APPROACH

    Directory of Open Access Journals (Sweden)

    Pankaj Gupta,

    2011-10-01

    Full Text Available Grid computing is a means of allocating the computational power of alarge number of computers to complex difficult computation orproblem. Grid computing is a distributed computing paradigm thatdiffers from traditional distributed computing in that it is aimed toward large scale systems that even span organizational boundaries. This paper proposes a method to achieve maximum fault tolerance in the Grid environment system by using Reliability consideration by using Replication approach and Check-point approach. Fault tolerance is an important property for large scale computational grid systems, where geographically distributed nodes co-operate to execute a task. In order to achieve high level of reliability and availability, the grid infrastructure should be a foolproof fault tolerant. Since the failure of resources affects job execution fatally, fault tolerance service is essential to satisfy QOS requirement in grid computing. Commonly utilized techniques for providing fault tolerance are job check pointing and replication. Both techniques mitigate the amount of work lost due to changing system availability but can introduce significant runtime overhead. The latter largely depends on the length of check pointing interval and the chosen number of replicas, respectively. In case of complex scientific workflows where tasks can execute in well defined order reliability is another biggest challenge because of the unreliable nature of the grid resources.

  8. Robot Position Sensor Fault Tolerance

    Science.gov (United States)

    Aldridge, Hal A.

    1997-01-01

    Robot systems in critical applications, such as those in space and nuclear environments, must be able to operate during component failure to complete important tasks. One failure mode that has received little attention is the failure of joint position sensors. Current fault tolerant designs require the addition of directly redundant position sensors which can affect joint design. A new method is proposed that utilizes analytical redundancy to allow for continued operation during joint position sensor failure. Joint torque sensors are used with a virtual passive torque controller to make the robot joint stable without position feedback and improve position tracking performance in the presence of unknown link dynamics and end-effector loading. Two Cartesian accelerometer based methods are proposed to determine the position of the joint. The joint specific position determination method utilizes two triaxial accelerometers attached to the link driven by the joint with the failed position sensor. The joint specific method is not computationally complex and the position error is bounded. The system wide position determination method utilizes accelerometers distributed on different robot links and the end-effector to determine the position of sets of multiple joints. The system wide method requires fewer accelerometers than the joint specific method to make all joint position sensors fault tolerant but is more computationally complex and has lower convergence properties. Experiments were conducted on a laboratory manipulator. Both position determination methods were shown to track the actual position satisfactorily. A controller using the position determination methods and the virtual passive torque controller was able to servo the joints to a desired position during position sensor failure.

  9. Methods and apparatuses for self-generating fault-tolerant keys in spread-spectrum systems

    Energy Technology Data Exchange (ETDEWEB)

    Moradi, Hussein; Farhang, Behrouz; Subramanian, Vijayarangam

    2015-12-15

    Self-generating fault-tolerant keys for use in spread-spectrum systems are disclosed. At a communication device, beacon signals are received from another communication device and impulse responses are determined from the beacon signals. The impulse responses are circularly shifted to place a largest sample at a predefined position. The impulse responses are converted to a set of frequency responses in a frequency domain. The frequency responses are shuffled with a predetermined shuffle scheme to develop a set of shuffled frequency responses. A set of phase differences is determined as a difference between an angle of the frequency response and an angle of the shuffled frequency response at each element of the corresponding sets. Each phase difference is quantized to develop a set of secret-key quantized phases and a set of spreading codes is developed wherein each spreading code includes a corresponding phase of the set of secret-key quantized phases.

  10. A Fault-tolerance Estimating Method for Ionosphere Corrections in Satellite Navigation System

    Institute of Scientific and Technical Information of China (English)

    GAO Shuliang; LI Rui; HUANG Zhigang

    2011-01-01

    Aiming to the reliable estimates of the ionosphere differential corrections for the satellite navigation system in the presence of the ionosphere anomaly,a fault-tolerance estimating method,which is based on the distributed Kalman filtering,is proposed.The method utilizes the parallel sub-filters for estimating the ionosphere differential corrections.Meanwhile,an infinite norm (IN) method is proposed for the detection of the ionosphere irregularity in the filter processing.Once the anomaly is detected,the sub-filter contaminated by the anomaly measurements will be excluded to ensure the reliability of the estimates.The simulation is conducted to validate the method and the results indicate that the anomaly can be found timely due to the novel fault detection method based on the infinite norm.Because of the parallel sub-filter architecture,the measurements are classified by the spatial distribution so that the ionosphere anomaly can be positioned and excluded more easily.Thus,the method can provide the robust and accurate ionosphere differential corrections.

  11. Task Mapping and Bandwidth Reservation for Mixed Hard/Soft Fault-Tolerant Embedded Systems

    DEFF Research Database (Denmark)

    Saraswat, Prabhat Kumar; Pop, Paul; Madsen, Jan

    2010-01-01

    In this paper we are interested in mixed hard/soft real-time fault-tolerant applications mapped on distributed heterogeneous architectures. We use the Earliest Deadline First (EDF) scheduling for the hard real-time tasks and the Constant Bandwidth Server (CBS) for the soft tasks. The bandwidth re...

  12. A novel N-input voting algorithm for X-by-wire fault-tolerant systems.

    Science.gov (United States)

    Karimi, Abbas; Zarafshan, Faraneh; Al-Haddad, S A R; Ramli, Abdul Rahman

    2014-01-01

    Voting is an important operation in multichannel computation paradigm and realization of ultrareliable and real-time control systems that arbitrates among the results of N redundant variants. These systems include N-modular redundant (NMR) hardware systems and diversely designed software systems based on N-version programming (NVP). Depending on the characteristics of the application and the type of selected voter, the voting algorithms can be implemented for either hardware or software systems. In this paper, a novel voting algorithm is introduced for real-time fault-tolerant control systems, appropriate for applications in which N is large. Then, its behavior has been software implemented in different scenarios of error-injection on the system inputs. The results of analyzed evaluations through plots and statistical computations have demonstrated that this novel algorithm does not have the limitations of some popular voting algorithms such as median and weighted; moreover, it is able to significantly increase the reliability and availability of the system in the best case to 2489.7% and 626.74%, respectively, and in the worst case to 3.84% and 1.55%, respectively. PMID:25386613

  13. A Novel N-Input Voting Algorithm for X-by-Wire Fault-Tolerant Systems

    Directory of Open Access Journals (Sweden)

    Abbas Karimi

    2014-01-01

    Full Text Available Voting is an important operation in multichannel computation paradigm and realization of ultrareliable and real-time control systems that arbitrates among the results of N redundant variants. These systems include N-modular redundant (NMR hardware systems and diversely designed software systems based on N-version programming (NVP. Depending on the characteristics of the application and the type of selected voter, the voting algorithms can be implemented for either hardware or software systems. In this paper, a novel voting algorithm is introduced for real-time fault-tolerant control systems, appropriate for applications in which N is large. Then, its behavior has been software implemented in different scenarios of error-injection on the system inputs. The results of analyzed evaluations through plots and statistical computations have demonstrated that this novel algorithm does not have the limitations of some popular voting algorithms such as median and weighted; moreover, it is able to significantly increase the reliability and availability of the system in the best case to 2489.7% and 626.74%, respectively, and in the worst case to 3.84% and 1.55%, respectively.

  14. Coordinated Fault Tolerance for High-Performance Computing

    Energy Technology Data Exchange (ETDEWEB)

    Dongarra, Jack; Bosilca, George; et al.

    2013-04-08

    Our work to meet our goal of end-to-end fault tolerance has focused on two areas: (1) improving fault tolerance in various software currently available and widely used throughout the HEC domain and (2) using fault information exchange and coordination to achieve holistic, systemwide fault tolerance and understanding how to design and implement interfaces for integrating fault tolerance features for multiple layers of the software stack—from the application, math libraries, and programming language runtime to other common system software such as jobs schedulers, resource managers, and monitoring tools.

  15. Modular, Fault-Tolerant Electronics Supporting Space Exploration Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Modern electronic systems tolerate only as many point failures as there are redundant system copies, using mere macro-scale redundancy. Fault Tolerant Electronics...

  16. Fault Tolerant Control: A Simultaneous Stabilization Result

    DEFF Research Database (Denmark)

    Stoustrup, Jakob; Blondel, V.D.

    2004-01-01

    This paper discusses the problem of designing fault tolerant compensators that stabilize a given system both in the nominal situation, as well as in the situation where one of the sensors or one of the actuators has failed. It is shown that such compensators always exist, provided that the system...

  17. A design fix to supervisory control for fault-tolerant scheduling of real-time multiprocessor systems with aperiodic tasks

    Science.gov (United States)

    Devaraj, Rajesh; Sarkar, Arnab; Biswas, Santosh

    2015-11-01

    In the article 'Supervisory control for fault-tolerant scheduling of real-time multiprocessor systems with aperiodic tasks', Park and Cho presented a systematic way of computing a largest fault-tolerant and schedulable language that provides information on whether the scheduler (i.e., supervisor) should accept or reject a newly arrived aperiodic task. The computation of such a language is mainly dependent on the task execution model presented in their paper. However, the task execution model is unable to capture the situation when the fault of a processor occurs even before the task has arrived. Consequently, a task execution model that does not capture this fact may possibly be assigned for execution on a faulty processor. This problem has been illustrated with an appropriate example. Then, the task execution model of Park and Cho has been modified to strengthen the requirement that none of the tasks are assigned for execution on a faulty processor.

  18. Parallel fault-tolerant robot control

    Science.gov (United States)

    Hamilton, D. L.; Bennett, J. K.; Walker, I. D.

    1992-01-01

    A shared memory multiprocessor architecture is used to develop a parallel fault-tolerant robot controller. Several versions of the robot controller are developed and compared. A robot simulation is also developed for control observation. Comparison of a serial version of the controller and a parallel version without fault tolerance showed the speedup possible with the coarse-grained parallelism currently employed. The performance degradation due to the addition of processor fault tolerance was demonstrated by comparison of these controllers with their fault-tolerant versions. Comparison of the more fault-tolerant controller with the lower-level fault-tolerant controller showed how varying the amount of redundant data affects performance. The results demonstrate the trade-off between speed performance and processor fault tolerance.

  19. Mapping of Fault-Tolerant Applications with Transparency on Distributed Embedded Systems

    DEFF Research Database (Denmark)

    Izosimov, Viacheslav; Pop, Paul; Eles, Petru;

    2006-01-01

    of the application. We propose an algorithm for the mapping of fault-tolerant applications with transparency. The algorithm decides a mapping of processes on computation nodes such that the application is schedulable and the transparency properties imposed by the designer are satisfied. The mapping algorithm...... is driven by a heuristic that is able to estimate the worst-case schedule length and indicate whether a certain mapping alternative is schedulable...

  20. Fault tolerant control schemes using integral sliding modes

    CERN Document Server

    Hamayun, Mirza Tariq; Alwi, Halim

    2016-01-01

    The key attribute of a Fault Tolerant Control (FTC) system is its ability to maintain overall system stability and acceptable performance in the face of faults and failures within the feedback system. In this book Integral Sliding Mode (ISM) Control Allocation (CA) schemes for FTC are described, which have the potential to maintain close to nominal fault-free performance (for the entire system response), in the face of actuator faults and even complete failures of certain actuators. Broadly an ISM controller based around a model of the plant with the aim of creating a nonlinear fault tolerant feedback controller whose closed-loop performance is established during the design process. The second approach involves retro-fitting an ISM scheme to an existing feedback controller to introduce fault tolerance. This may be advantageous from an industrial perspective, because fault tolerance can be introduced without changing the existing control loops. A high fidelity benchmark model of a large transport aircraft is u...

  1. Fault-Tolerant, Real-Time, Multi-Core Computer System

    Science.gov (United States)

    Gostelow, Kim P.

    2012-01-01

    A document discusses a fault-tolerant, self-aware, low-power, multi-core computer for space missions with thousands of simple cores, achieving speed through concurrency. The proposed machine decides how to achieve concurrency in real time, rather than depending on programmers. The driving features of the system are simple hardware that is modular in the extreme, with no shared memory, and software with significant runtime reorganizing capability. The document describes a mechanism for moving ongoing computations and data that is based on a functional model of execution. Because there is no shared memory, the processor connects to its neighbors through a high-speed data link. Messages are sent to a neighbor switch, which in turn forwards that message on to its neighbor until reaching the intended destination. Except for the neighbor connections, processors are isolated and independent of each other. The processors on the periphery also connect chip-to-chip, thus building up a large processor net. There is no particular topology to the larger net, as a function at each processor allows it to forward a message in the correct direction. Some chip-to-chip connections are not necessarily nearest neighbors, providing short cuts for some of the longer physical distances. The peripheral processors also provide the connections to sensors, actuators, radios, science instruments, and other devices with which the computer system interacts.

  2. Advanced Information Processing System (AIPS)-based fault tolerant avionics architecture for launch vehicles

    Science.gov (United States)

    Lala, Jaynarayan H.; Harper, Richard E.; Jaskowiak, Kenneth R.; Rosch, Gene; Alger, Linda S.; Schor, Andrei L.

    1990-01-01

    An avionics architecture for the advanced launch system (ALS) that uses validated hardware and software building blocks developed under the advanced information processing system program is presented. The AIPS for ALS architecture defined is preliminary, and reliability requirements can be met by the AIPS hardware and software building blocks that are built using the state-of-the-art technology available in the 1992-93 time frame. The level of detail in the architecture definition reflects the level of detail available in the ALS requirements. As the avionics requirements are refined, the architecture can also be refined and defined in greater detail with the help of analysis and simulation tools. A useful methodology is demonstrated for investigating the impact of the avionics suite to the recurring cost of the ALS. It is shown that allowing the vehicle to launch with selected detected failures can potentially reduce the recurring launch costs. A comparative analysis shows that validated fault-tolerant avionics built out of Class B parts can result in lower life-cycle-cost in comparison to simplex avionics built out of Class S parts or other redundant architectures.

  3. Abnormal fault-recovery characteristics of the fault-tolerant multiprocessor uncovered using a new fault-injection methodology

    Science.gov (United States)

    Padilla, Peter A.

    1991-03-01

    An investigation was made in AIRLAB of the fault handling performance of the Fault Tolerant MultiProcessor (FTMP). Fault handling errors detected during fault injection experiments were characterized. In these fault injection experiments, the FTMP disabled a working unit instead of the faulted unit once in every 500 faults, on the average. System design weaknesses allow active faults to exercise a part of the fault management software that handles Byzantine or lying faults. Byzantine faults behave such that the faulted unit points to a working unit as the source of errors. The design's problems involve: (1) the design and interface between the simplex error detection hardware and the error processing software, (2) the functional capabilities of the FTMP system bus, and (3) the communication requirements of a multiprocessor architecture. These weak areas in the FTMP's design increase the probability that, for any hardware fault, a good line replacement unit (LRU) is mistakenly disabled by the fault management software.

  4. Validation Methods Research for Fault-Tolerant Avionics and Control Systems Sub-Working Group Meeting. CARE 3 peer review

    Science.gov (United States)

    Trivedi, K. S. (Editor); Clary, J. B. (Editor)

    1980-01-01

    A computer aided reliability estimation procedure (CARE 3), developed to model the behavior of ultrareliable systems required by flight-critical avionics and control systems, is evaluated. The mathematical models, numerical method, and fault-tolerant architecture modeling requirements are examined, and the testing and characterization procedures are discussed. Recommendations aimed at enhancing CARE 3 are presented; in particular, the need for a better exposition of the method and the user interface is emphasized.

  5. Focused fault injection testing of software implemented fault tolerance mechanisms of Voltan TMR nodes

    Science.gov (United States)

    Tao, S.; Ezhilchelvan, P. D.; Shrivastava, S. K.

    1995-03-01

    One way of gaining confidence in the adequacy of fault tolerance mechanisms of a system is to test the system by injecting faults and see how the system performs under faulty conditions. This paper presents an application of the focused fault injection method that has been developed for testing software implemented fault tolerance mechanisms of distributed systems. The method exploits the object oriented approach of software implementation to support the injection of specific classes of faults. With the focused fault injection method, the system tester is able to inject specific classes of faults (including malicious ones) such that the fault tolerance mechanisms of a target system can be tested adequately. The method has been applied to test the design and implementation of voting, clock synchronization, and ordering modules of the Voltan TMR (triple modular redundant) node. The tests performed uncovered three flaws in the system software.

  6. 基于容错观测器的容错控制系统集成设计%Integrated Design of Fault Tolerant Control System Based on Fault Tolerant Observer

    Institute of Scientific and Technical Information of China (English)

    唐小静; 谢琳; 任章; 徐德民

    2001-01-01

    Fault Detection and Diagnosis (FDD) is the first step in fault tolerant control system design. The feature of our design is the integration of FDD with fault tolerant controller, which was rarely done in previous such designs and is different from our way of integration. Our integration is different in that, under sensor failures, we can asymptotically estimate the real states of the system. Asymptotic estimation is discussed in considerable detail in section 2. The integrated design method is observer-based. Our fault tolerant observer can do two things: (1) asymptotic estimation of the real states of the system, (2) detection of sensor failures. Our observer, different from generally used one, is able to compensate for fault signal, thus making asymptotic estimation possible. Simulation results of an autonomous underwater vehicle , given in Figs.2 through 5, show preliminarily the effectiveness of our design%针对一类传感器故障的线性控制系统,设计出一个能在故障情况下正确估计出系统真实状态的容错观测器,并在此基础上实现对传感器故障的容错控制。结合某水下自主航行器(AUV)航向控制系统传感器故障的仿真结果验证了所提方案的有效性。

  7. Active fault tolerant control of piecewise affine systems with reference tracking and input constraints

    DEFF Research Database (Denmark)

    Gholami, M.; Cocquempot, V.; Schiøler, H.;

    2014-01-01

    performance of the faulty system are held. The design of the supervisory scheme is not considered here. The set of controllers is composed of a normal controller for the fault-free case, an active fault detection and isolation controller for isolation and identification of the faults, and a set of passive...... the reference signal while the control inputs are bounded. The PFTC problem is transformed into a feasibility problem of a set of LMIs. The method is applied on a large-scale live-stock ventilation model....

  8. System Wide Joint Position Sensor Fault Tolerance in Robot Systems Using Cartesian Accelerometers

    Science.gov (United States)

    Aldridge, Hal A.; Juang, Jer-Nan

    1997-01-01

    Joint position sensors are necessary for most robot control systems. A single position sensor failure in a normal robot system can greatly degrade performance. This paper presents a method to obtain position information from Cartesian accelerometers without integration. Depending on the number and location of the accelerometers. the proposed system can tolerate the loss of multiple position sensors. A solution technique suitable for real-time implementation is presented. Simulations were conducted using 5 triaxial accelerometers to recover from the loss of up to 4 joint position sensors on a 7 degree of freedom robot moving in general three dimensional space. The simulations show good estimation performance using non-ideal accelerometer measurements.

  9. Thermoelectric-Driven Sustainable Sensing and Actuation Systems for Fault-Tolerant Nuclear Incidents

    Energy Technology Data Exchange (ETDEWEB)

    Longtin, Jon [Stony Brook Univ., NY (United States)

    2016-02-08

    safety systems, etc. Such an approach is intrinsically fault tolerant: in the event that system temperatures increase, the amount of available energy will increase, which will make more power available for applications. The system can also be used during normal conditions to provide enhanced monitoring of key system components.

  10. Thermoelectric-Driven Sustainable Sensing and Actuation Systems for Fault-Tolerant Nuclear Incidents

    International Nuclear Information System (INIS)

    safety systems, etc. Such an approach is intrinsically fault tolerant: in the event that system temperatures increase, the amount of available energy will increase, which will make more power available for applications. The system can also be used during normal conditions to provide enhanced monitoring of key system components.

  11. Robust Fault-Tolerant Control for Uncertain Networked Control Systems with State-Delay and Random Data Packet Dropout

    Directory of Open Access Journals (Sweden)

    Xiaomei Qi

    2012-01-01

    Full Text Available A robust fault-tolerant controller design problem for networked control system (NCS with random packet dropout in both sensor-to-controller link and controller-to-actuator link is investigated. A novel stochastic NCS model with state-delay, model uncertainty, disturbance, probabilistic sensor failure, and actuator failure is proposed. The random packet dropout, sensor failures, and actuator failures are characterized by a binary random variable. The sufficient condition for asymptotical mean-square stability of NCS is derived and the closed-loop NCS satisfies H∞ performance constraints caused by the random packet dropout and disturbance. The fault-tolerant controller is designed by solving a linear matrix inequality. A numerical example is presented to illustrate the effectiveness of the proposed method.

  12. Low-Cost Fault Tolerant Methodology for Real Time MPSoC Based Embedded System

    Directory of Open Access Journals (Sweden)

    Mohsin Amin

    2014-01-01

    Full Text Available We are proposing a design methodology for a fault tolerant homogeneous MPSoC having additional design objectives that include low hardware overhead and performance. We have implemented three different FT methodologies on MPSoCs and compared them against the defined constraints. The comparison of these FT methodologies is carried out by modelling their architectures in VHDL-RTL, on Spartan 3 FPGA. The results obtained through simulations helped us to identify the most relevant scheme in terms of the given design constraints.

  13. Improving Information Security by Implementing Fault Tolerance Concepts

    OpenAIRE

    Aurel Serb

    2014-01-01

    Security issues are complex, and the risks of cyber crime are often difficult to stipulate, even for experts. The issues presented in this article try to be formed in a contribution to the consolidation of problems in the field of computer arhitecture cyber security. Fault tolerance is the best guarantee that high-confidence systems will not succumb to physical, design, or human-machine interaction faults. A fault tolerant system is one that can continue to operate reliably by producing accep...

  14. Design Optimization of Time- and Cost-Constrained Fault-Tolerant Embedded Systems with Checkpointing and Replication

    DEFF Research Database (Denmark)

    Pop, Paul; Izosimov, Viacheslav; Eles, Petru;

    2009-01-01

    decides the assignment of fault-tolerance policies to processes, the optimal placement of checkpoints and the mapping of processes to processors such that multiple transient faults are tolerated and the timing constraints of the application are satisfied. We present several design optimization approaches...

  15. A Piecewise Affine Hybrid Systems Approach to Fault Tolerant Satellite Formation Control

    DEFF Research Database (Denmark)

    Grunnet, Jacob Deleuran; Larsen, Jesper Abildgaard; Bak, Thomas;

    2008-01-01

    In this paper a procedure for modelling satellite formations   including failure dynamics as a piecewise-affine hybrid system is   shown. The formulation enables recently developed methods and tools   for control and analysis of piecewise-affine systems to be applied   leading to synthesis of fault...

  16. Fault Tolerant Ethernet Based Network for Time Sensitive Applications in Electrical Power Distribution Systems

    Directory of Open Access Journals (Sweden)

    Leos Bohac

    2013-01-01

    Full Text Available The paper analyses and experimentally verifies deployment of Ethernet based network technology to enable fault tolerant and timely exchange of data among a number of high voltage protective relays that use proprietary serial communication line to exchange data in real time on a state of its high voltage circuitry facilitating a fast protection switching in case of critical failures. The digital serial signal is first fetched into PCM multiplexer where it is mapped to the corresponding E1 (2 Mbit/s time division multiplexed signal. Subsequently, the resulting E1 frames are then packetized and sent through Ethernet control LAN to the opposite PCM demultiplexer where the same but reverse processing is done finally sending a signal into the opposite protective relay. The challenge of this setup is to assure very timely delivery of the control information between protective relays even in the cases of potential failures of Ethernet network itself. The tolerance of Ethernet network to faults is assured using widespread per VLAN Rapid Spanning Tree Protocol potentially extended by 1+1 PCM protection as a valuable option.

  17. Evaluation of Simple Causal Message Logging for Large-Scale Fault Tolerant HPC Systems

    Energy Technology Data Exchange (ETDEWEB)

    Bronevetsky, G; Meneses, E; Kale, L V

    2011-02-25

    The era of petascale computing brought machines with hundreds of thousands of processors. The next generation of exascale supercomputers will make available clusters with millions of processors. In those machines, mean time between failures will range from a few minutes to few tens of minutes, making the crash of a processor the common case, instead of a rarity. Parallel applications running on those large machines will need to simultaneously survive crashes and maintain high productivity. To achieve that, fault tolerance techniques will have to go beyond checkpoint/restart, which requires all processors to roll back in case of a failure. Incorporating some form of message logging will provide a framework where only a subset of processors are rolled back after a crash. In this paper, we discuss why a simple causal message logging protocol seems a promising alternative to provide fault tolerance in large supercomputers. As opposed to pessimistic message logging, it has low latency overhead, especially in collective communication operations. Besides, it saves messages when more than one thread is running per processor. Finally, we demonstrate that a simple causal message logging protocol has a faster recovery and a low performance penalty when compared to checkpoint/restart. Running NAS Parallel Benchmarks (CG, MG and BT) on 1024 processors, simple causal message logging has a latency overhead below 5%.

  18. Fault-Tolerant Process Control Methods and Applications

    CERN Document Server

    Mhaskar, Prashant; Christofides, Panagiotis D

    2013-01-01

    Fault-Tolerant Process Control focuses on the development of general, yet practical, methods for the design of advanced fault-tolerant control systems; these ensure an efficient fault detection and a timely response to enhance fault recovery, prevent faults from propagating or developing into total failures, and reduce the risk of safety hazards. To this end, methods are presented for the design of advanced fault-tolerant control systems for chemical processes which explicitly deal with actuator/controller failures and sensor faults and data losses. Specifically, the book puts forward: ·         a framework for  detection, isolation and diagnosis of actuator and sensor faults for nonlinear systems; ·         controller reconfiguration and safe-parking-based fault-handling methodologies; ·         integrated-data- and model-based fault-detection and isolation and fault-tolerant control methods; ·         methods for handling sensor faults and data losses; and ·      ...

  19. Measures of Fault Tolerance in Distributed Simulated Annealing

    OpenAIRE

    Prakash, Aaditya

    2012-01-01

    In this paper, we examine the different measures of Fault Tolerance in a Distributed Simulated Annealing process. Optimization by Simulated Annealing on a distributed system is prone to various sources of failure. We analyse simulated annealing algorithm, its architecture in distributed platform and potential sources of failures. We examine the behaviour of tolerant distributed system for optimization task. We present possible methods to overcome the failures and achieve fault tolerance for t...

  20. Development of an interface for an ultrareliable fault-tolerant control system and an electronic servo-control unit

    Science.gov (United States)

    Shaver, Charles; Williamson, Michael

    1986-01-01

    The NASA Ames Research Center sponsors a research program for the investigation of Intelligent Flight Control Actuation systems. The use of artificial intelligence techniques in conjunction with algorithmic techniques for autonomous, decentralized fault management of flight-control actuation systems is explored under this program. The design, development, and operation of the interface for laboratory investigation of this program is documented. The interface, architecturally based on the Intel 8751 microcontroller, is an interrupt-driven system designed to receive a digital message from an ultrareliable fault-tolerant control system (UFTCS). The interface links the UFTCS to an electronic servo-control unit, which controls a set of hydraulic actuators. It was necessary to build a UFTCS emulator (also based on the Intel 8751) to provide signal sources for testing the equipment.

  1. Enhancement of Fault Tolerance in Cloud Computing

    OpenAIRE

    Pushpanjali Gupta; Rasmi Ranjan Patra

    2014-01-01

    In recent years researchers are trying to work out scientific applications in cloud so that it decreases the infrastructure cost and increases the span of team and finally innovative ideas towards applications is increased. But the cloud is still not as much reliable, controllable as grid. So in the evolving Cloud computing environment there is a great need of fault tolerance mechanism for the system to work effectively even in the presence of failure. Moreover Big Organizations ar...

  2. SURVNET: A Fault Tolerant Local Area Network

    Science.gov (United States)

    Katz, J. L.; Metcalf, B. D.

    1987-01-01

    In response to the Department of Defense's need to enhance the survivability of command and control systems, The MITRE Corporation developed SURVNET, a survivable fiber optic local area network. The network supports data communications with a fault-tolerant, distributed architecture capable of continued communication despite media failure and node outages. SURVNET is configured as a modified fiber-optic broadcast bus. The physical and data link layers are implemented with a combination of IEEE 802.3 (Ethernet) and an augmented version of IEEE 802.4 token passing bus protocols. Special nodes in the network, incorporating fault-tolerant software, are doubly connected to the fiber bus. Periodically, these nodes broadcast a self-addressed test message to determine if continuity exists on the network segment between the node's two physically separate connections. If a discontinuity is detected, the node utilizes its two connections to bridge between the isolated bus segments.

  3. A Dynamic Slack Management Technique for Real-Time Distributed Embedded System with Enhanced Fault Tolerance and Resource Constraints

    Directory of Open Access Journals (Sweden)

    Santhi Baskaran,

    2011-01-01

    Full Text Available This project work aims to develop a dynamic slack management technique, for real-time distributed embedded systems to reduce the total energy consumption in addition to timing, precedence and resource constraints. The Slack Distribution Technique proposed considers a modified Feedback Control Scheduling (FCS algorithm. This algorithm schedules dependent tasks effectively with precedence and resource constraints. It further minimizes the schedule length and utilizes the available slack to increase the energy efficiency. A fault tolerant mechanism uses a deferred-active-backup scheme increases the schedulability and provides reliability to the system.

  4. Multi-Fault Tolerance ofAircraft Control Surface Based on Fault-Tolerant Multi-Agent System%基于容错多智能体系统的飞机舵面多故障容错

    Institute of Scientific and Technical Information of China (English)

    袁侃; 胡寿松

    2011-01-01

    To solve the problem of multi-fault diagnosis of complex systems, the basic concept of MultiAgent Systems (MAS) is expanded to establish the concept of Fault-Tolerant Multi-Agent System (FATMAS). Based on which the definitions of various functions, rules and flows for realizing multi-fault tolerance in FATMAS are given. Then the multiple faults can be detected by calling different functions of the system according to some definite flows, and the system can recover from the faults by copying the tasks of non-critical agents. The results of simulation in the F-16 aircraft multi-fault diagnosis and self-repairing illustrated that this method can effectively reduce the number of replicated agents through clear inter-agent message passing mechanism, and it is relatively close to the process of dealing with failures in actual system,therefore it can be used in complex system for multi-fault diagnosis and tolerance.%为解决复杂系统的多故障容错问题,首先将多智能体系统(MAS)的基本概念进行了扩充,定义了容错多智能体系统(FATMAS)的相关概念,并在此基础上提出了在FATMAS中实现多故障容错的各类函数定义、规则与流程.然后按照一定的流程调用不同函数就可对系统中的多故障进行检测,并可通过复制非关键智能体的任务使系统从多故障中恢复运行.F-16飞机多故障诊断与自修复的仿真结果说明,该方法能够通过清晰的智能体间消息传递机制有效地减少系统中复制智能体的数目,而且比较接近于实际系统中的故障处理过程,可用于复杂系统的多故障诊断与容错.

  5. Massive Sensor Array Fault Tolerance: Tolerance Mechanism and Fault Injection for Validation

    Directory of Open Access Journals (Sweden)

    Dugan Um

    2010-01-01

    Full Text Available As today's machines become increasingly complex in order to handle intricate tasks, the number of sensors must increase for intelligent operations. Given the large number of sensors, detecting, isolating, and then tolerating faulty sensors is especially important. In this paper, we propose fault tolerance architecture suitable for a massive sensor array often found in highly advanced systems such as autonomous robots. One example is the sensitive skin, a type of massive sensor array. The objective of the sensitive skin is autonomous guidance of machines in unknown environments, requiring elongated operations in a remote site. The entirety of such a system needs to be able to work remotely without human attendance for an extended period of time. To that end, we propose a fault-tolerant architecture whereby component and analytical redundancies are integrated cohesively for effective failure tolerance of a massive array type sensor or sensor system. In addition, we discuss the evaluation results of the proposed tolerance scheme by means of fault injection and validation analysis as a measure of system reliability and performance.

  6. Guaranteed Cost Active Fault-tolerant Control of Networked Control System with Packet Dropout and Transmission Delay

    Institute of Scientific and Technical Information of China (English)

    Xiao-Yuan Luo; Mei-Jie Shang; Cai-Lian Chen; Xin-Ping Guan

    2010-01-01

    The problem of guaranteed cost active fault-tolerant controller (AFTC) design for networked control systems (NCSs)with both packet dropout and transmission delay is studied in this paper.Considering the packet dropout and transmission delay,a piecewise constant controller is adopted.With a guaranteed cost function,optimal controllers whose number is equal to the number of actuators are designed,and the design process is formulated as a convex optimal problem that can be solved by existing software.The control strategy is proposed as follows:when actuator failures appear,the fault detection and isolation unit sends out the information to the controller choosing strategy,and then the optimal stabilizing controller with the smallest guaranteed cost value is chosen.Two illustrative examples are given to demonstrate the effectiveness of the proposed approach.By comparing with the existing methods,it can be seen that our method has a better performance.

  7. A Dynamic Effective Fault Tolerance System in Robotic Manipulator using a Hybrid Neural Network based Controller

    Directory of Open Access Journals (Sweden)

    G. Jiji

    2014-04-01

    Full Text Available Robot manipulator play important role in the field of automobile industry, mainly it is used in gas welding application and manufacturing and assembling of motor parts. In complex trajectory, on each joint the speed of the robot manipulator is affected. For that reason, it is necessary to analyze the noise and vibration of robot's joints for predicting faults also improve the control precision of robotic manipulator. In this study we will propose a new fault detection system for Robot manipulator. The proposed hybrid fault detection system is designed based on fuzzy support vector machine and Artificial Neural Networks (ANNs. In this system the decouple joints are identified and corrected using fuzzy SVM, here non-linear signal are used for complete process and treatment, the Artificial Neural Networks (ANNs are used to detect the free-swinging and locked joint of the robot, two types of neural predictors are also employed in the proposed adaptive neural network structure. The simulation results of a hybrid controller demonstrate the feasibility and performance of the methodology.

  8. Microcontroller-Based Fault Tolerant Data Acquisition System For Air Quality Monitoring And Control Of Environmental Pollution

    Directory of Open Access Journals (Sweden)

    Tochukwu Chiagunye

    2015-08-01

    Full Text Available ABSTRACT The design applied Passive fault tolerance to a microcontroller based data acquisition system to achieve the stated considerations where redundant sensors and microcontrollers with associated circuitry were designed and implemented to enable measurement of pollutant concentration information from chimney vents in two industry. Microsoft visual basic was used to develop a data mining tool which implemented an underlying artificial neural network model for forecasting pollutant concentrations for future time periods. The feed forward back propagation method was used to train the ANN model with a training data set while a decision tree algorithm was used to select an optimal output result for the model from its two output neurons.

  9. Diagnosis and Fault-tolerant Control, 2nd edition

    DEFF Research Database (Denmark)

    Blanke, Mogens; Kinnaert, Michel; Lunze, Jan;

    to ensure fault tolerance. Design methods for diagnostic systems and fault-tolerant controllers are presented for processes that are described by analytical models, by discrete-event models or that can be dealt with as quantised systems. Five case studies on pilot processes show the applicability......Fault-tolerant control aims at a graceful degradation of the behaviour of automated systems in case of faults. It satisfies the industrial demand for enhanced availability and safety, in contrast to traditional reactions to faults that bring about sudden shutdowns and loss of availability. The book...... of the presented methods. The theoretical results are illustrated by two running examples used throughout the book. The second edition includes new material about reconfigurable control, diagnosis of nonlinear systems, and remote diagnosis. The application examples are extended by a steering-by-wire system...

  10. Study on inverter fault-tolerant operation of PMSM DTC

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    This paper presents an investigation of inverter fault-tolerant operation for a permanent magnet synchronous motor (PMSM) direct torque control (DTC) system under various inverter faults. The performance of a faulty standard 6-switch inverter driven PMSM DTC system is analyzed. To avoid the loss or even disaster caused by the inverter faults, a topology-modified inverter with fault-tolerant capability is introduced, which is reconfigured as a 3-phase 4-switch inverter. The modeling of the 4-switch inverter is then analyzed and a novel DTC strategy with a unique nonlinear perpendicular flux observer and feedback compensation scheme is proposed for obtaining a continuous, disturbance-free drive system. The simulation and experimental results demonstrate that the proposed inverter fault-tolerant PMSM DTC system is able to operate stably and continuously with acceptable static and pretty good dynamic performance.

  11. Fault tolerance and reliability in integrated ship control

    DEFF Research Database (Denmark)

    Nielsen, Jens Frederik Dalsgaard; Izadi-Zamanabadi, Roozbeh; Schiøler, Henrik

    2002-01-01

    Various strategies for achieving fault tolerance in large scale control systems are discussed. The positive and negative impacts of distribution through network communication are presented. The ATOMOS framework for standardized reliable marine automation is presented along with the corresponding...

  12. Fault-Tolerant Precision Formation Guidance for Interferometry Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A methodology is to be developed that will allow the development and implementation of fault-tolerant control system for distributed collaborative spacecraft. The...

  13. A SAFE approach towards early design space exploration of Fault-tolerant multimedia MPSoCs

    NARCIS (Netherlands)

    P. van Stralen; A. Pimentel

    2012-01-01

    With the reduction in feature size, transient errors start to play an important role in modern embedded systems. It is therefore important to make fault-tolerance a first-class citizen in embedded system design. Fault-tolerance patterns are techniques to make an application fault-tolerant. Not only

  14. Software reliability through fault-avoidance and fault-tolerance

    Science.gov (United States)

    Vouk, Mladen A.; Mcallister, David F.

    1993-01-01

    Strategies and tools for the testing, risk assessment and risk control of dependable software-based systems were developed. Part of this project consists of studies to enable the transfer of technology to industry, for example the risk management techniques for safety-concious systems. Theoretical investigations of Boolean and Relational Operator (BRO) testing strategy were conducted for condition-based testing. The Basic Graph Generation and Analysis tool (BGG) was extended to fully incorporate several variants of the BRO metric. Single- and multi-phase risk, coverage and time-based models are being developed to provide additional theoretical and empirical basis for estimation of the reliability and availability of large, highly dependable software. A model for software process and risk management was developed. The use of cause-effect graphing for software specification and validation was investigated. Lastly, advanced software fault-tolerance models were studied to provide alternatives and improvements in situations where simple software fault-tolerance strategies break down.

  15. Nonlinear, Adaptive and Fault-tolerant Control for Electro-hydraulic Servo Systems

    DEFF Research Database (Denmark)

    Choux, Martin

    Fluid power systems have been in use since 1795 with the rst hydraulic press patented by Joseph Bramah and today form the basis of many industries. Electro hydraulic servo systems are uid power systems controlled in closed-loop. They transform reference input signals into a set of movements...... numerous attractive properties, hydraulic systems are always subject to potential leakages in their components, friction variation in their hydraulic actuators and deciency in their sensors. These violations of normal behaviour reduce the system performances and can lead to system failure......-tolerant control for a representative electro hydraulic servo controlled motion system. The thesis extends existing models of hydraulic systems by considering more detailed dynamics in the servo valve and in the friction inside the hydraulic cylinder. It identies the model parameters using experimental data from...

  16. Fault-tolerant control for current sensors of doubly fed induction generators based on an improved fault detection method

    DEFF Research Database (Denmark)

    Li, Hui; Yang, Chao; Hu, Yaogang;

    2014-01-01

    Fault-tolerant control of current sensors is studied in this paper to improve the reliability of a doubly fed induction generator (DFIG). A fault-tolerant control system of current sensors is presented for the DFIG, which consists of a new current observer and an improved current sensor fault...... detection algorithm, and fault-tolerant control system are investigated by simulation. The results indicate that the outputs of the observer and the sensor are highly coherent. The fault detection algorithm can efficiently detect both soft and hard faults in current sensors, and the fault-tolerant control...... system can effectively tolerate both types of faults. © 2013 Published by Elsevier Ltd. All rights reserved....

  17. Fault-tolerant and Diagnostic Methods for Navigation

    DEFF Research Database (Denmark)

    Blanke, Mogens

    2003-01-01

    to diagnose faults and autonomously provide valid navigation data, disregarding any faulty sensor data and use sensor fusion to obtain a best estimate for users. This paper discusses how diagnostic and fault-tolerant methods are applicable in marine systems. An example chosen is sensor fusion for navigation...

  18. Fault tolerant programmable digital attitude control electronics study

    Science.gov (United States)

    Sorensen, A. A.

    1974-01-01

    The attitude control electronics mechanization study to develop a fault tolerant autonomous concept for a three axis system is reported. Programmable digital electronics are compared to general purpose digital computers. The requirements, constraints, and tradeoffs are discussed. It is concluded that: (1) general fault tolerance can be achieved relatively economically, (2) recovery times of less than one second can be obtained, (3) the number of faulty behavior patterns must be limited, and (4) adjoined processes are the best indicators of faulty operation.

  19. A Proactive Fault Tolerant Strategy for Desktop Grid

    OpenAIRE

    Geeta Arora; Dr. Shaveta Rani; Dr. Paramjit Singh

    2015-01-01

    Desktop Grid resources are volatile, heterogeneous and geographically distributed in nature, so scheduling and fault tolerance become the important challenges for Desktop grid systems. In this paper a proactive fault tolerant strategy is developed which also considers the unwanted delays in association with speed and load of resources in the Grid while scheduling jobs on Grid resources. Simulation experiments are conducted by using GridSim toolkit 5.2. The experimental results obtained from a...

  20. Incorporating Fault Tolerance Tactics in Software Architecture Patterns

    NARCIS (Netherlands)

    Harrison, Neil B.; Avgeriou, Paris

    2008-01-01

    One important way that an architecture impacts fault tolerance is by making it easy or hard to implement measures that improve fault tolerance. Many such measures are described as fault tolerance tactics. We studied how various fault tolerance tactics can be implemented in the best-known architectur

  1. On Fault Tolerance of Resources in Computational Grids

    Directory of Open Access Journals (Sweden)

    Arindam Das

    2012-10-01

    Full Text Available Grid computing or computational grid is always a vast research field in academic, as well as in industryalso. Computational grid provides resource sharing through multi-institutional virtual organizations fordynamic problem solving. Various heterogeneous resources of different administrative domain are virtuallydistributed through different network in computational grids. Thus any type of failure can occur at anypoint of time and job running in grid environment might fail. Hence fault tolerance is an important andchallenging issue in grid computing as the dependability of individual grid resources may not beguaranteed. In order to make computational grids more effective and reliable fault tolerant system isnecessary. The objective of this paper is to review different existing fault tolerance techniques applicable ingrid computing. This paper presents state of the art of various fault tolerance technique and comparativestudy of the existing algorithms.

  2. Object Replication and CORBA Fault-Tolerant Object Service

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    CORBA (Common Object Request Broker Arc hitecture) provides 16Common Object Services for distributed application develo pment, but none of them are fault-tolerance related services. In this paper, we propose a replicated object based Fault-Tolerant Object Service (FTOS) for COR BA environment. Two fault-tolerant mechanisms are provided in FTOS including dy namic voting mechanism and object replication mechanism. The dynamic voting mech anism uses majority-voting strategy to ensure object state consistency in failu re situations. The object replication mechanism can help system administrators t o replicate and start-up objects easily. Our implementation provides a library according to the style of COSS. With this library, programmers can develop distr ibuted applications with fault-tolerance capability very easily.

  3. The New Fault Tolerant Onboard Computer for Microsatellite Missions

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    This paper describes an onboard computer with dual processing modules. Each processing module is composed of 32 bit ARM reduced instruction set computer processor and other commercial-off-the-shelf devices. A set of fault handling mechanisms is implemented in the computer system, which enables the system to tolerate a single fault. The onboard software is organized around a set of processes that communicate among each other through a routing process. Meeting an extremely tight set of constraints that include mass, volume, power consumption and space environmental conditions, the fault-tolerant onboard computer has excellent data processing capability that can meet the erquirements of micro-satellite missions.

  4. USAGE OF STANDARD PERSONAL COMPUTER PORTS FOR DESIGNING OF THE DOUBLE REDUNDANT FAULT-TOLERANT COMPUTER CONTROL SYSTEMS

    Directory of Open Access Journals (Sweden)

    Rafig SAMEDOV

    2005-01-01

    Full Text Available In this study, for designing of the fault-tolerant control systems by using standard personal computers, the ports have been investigated, different structure versions have been designed and the method for choosing of an optimal structure has been suggested. In this scope, first of all, the ÇİFTYAK system has been defined and its work principle has been determined. Then, data transmission ports of the standard personal computers have been classified and analyzed. After that, the structure versions have been designed and evaluated according to the used data transmission methods, the numbers of ports and the criterions of reliability, performance, truth, control and cost. Finally, the method for choosing of the most optimal structure version has been suggested.

  5. Analysis of the survivability of the shuttle (ALT) fault-tolerant avionics system

    Science.gov (United States)

    1976-01-01

    An extension of the Complementary-Analytic-Simulative Technique (CAST) is presented which is applicable to the Shuttle Data Processing Subsystem (DPS). A two step process was used. The first step provides models, both analytic and simulative, for analysis of the Approach-Landing Test (ALT) configuration. The ALT modeling and analysis are presented. Since CAST had already been shown to be multicomputer systems, the emphasis was placed on extending the CAST concept so it is applicable to computer systems including the multiplicity of input and output devices found in a real-time control system application. The DPS mission-critical survivability for a six-hour mission was determined to be 0.999863 for the Shuttle ALT baseline configuration. Thus it can be said that for ALT, the survivability is adequate. However, the fact that orbiting missions of up to 30 days are planned illustrates the necessity of extending the ALT work to be applicable to OFT and actual mission scenarios. The above analysis led to the evaluation of three selected options which identified two areas of possible improvement. These improvements would result from use of a recovery technique which combines roll ahead with memory copy, and increased TACAN fault detectability.

  6. Enhancement of Fault Tolerance in Cloud Computing

    Directory of Open Access Journals (Sweden)

    Pushpanjali Gupta

    2014-08-01

    Full Text Available In recent years researchers are trying to work out scientific applications in cloud so that it decreases the infrastructure cost and increases the span of team and finally innovative ideas towards applications is increased. But the cloud is still not as much reliable, controllable as grid. So in the evolving Cloud computing environment there is a great need of fault tolerance mechanism for the system to work effectively even in the presence of failure. Moreover Big Organizations are also opting for using Hybrid Cloud instead of private Cloud. Thus, in this paper we propose an approach of using a new framework in Cloud so as to use Cloud for scientific applications as well makes the public Cloud trustworthy platform. There is a progressive approach introduced to provide an effective way to achieve high fault tolerance in Clouds by enabling a new workflow planning method to balance performance, reliability and cost for critical scientific applications and focus mainly on use of distributed resources for workflow execution mainly in serial and concurrent manner.

  7. ENHANCEMENT OF FAULT TOLERANCE IN CLOUD COMPUTING

    Directory of Open Access Journals (Sweden)

    Pushpanjali Gupta

    2015-10-01

    Full Text Available In recent years researchers are trying to work out scientific applications in cloud so that it decreases the infrastructure cost and increases the span of team and finally innovative ideas towards applications is increased. But the cloud is still not as much reliable, controllable as grid. So in the evolving Cloud computing environment there is a great need of fault tolerance mechanism for the system to work effectively even in the presence of failure. Moreover Big Organizations are also opting for using Hybrid Cloud instead of private Cloud. Thus, in this paper we propose an approach of using a new framework in Cloud so as to use Cloud for scientific applications as well makes the public Cloud trustworthy platform. There is a progressive approach introduced to provide an effective way to achieve high fault tolerance in Clouds by enabling a new workflow planning method to balance performance, reliability and cost for critical scientific applications and focus mainly on use of distributed resources for workflow execution mainly in serial and concurrent manner.

  8. DESIGN AND IMPLEMENTATION OF PROCESS FAULT-TOLERANT SYSTEM FOR HIGH-PERFORMANCE FAULT-TOLERANT COMPUTER%面向高端容错计算机的进程容错系统设计与实现

    Institute of Scientific and Technical Information of China (English)

    吴楠; 张东; 刘璧怡

    2013-01-01

    High-end fault-tolerant computers are mainly used in key sectors such as banking and telecommunications, and are extremely sensitive to failure, so it is extremely important to guarantee the availability of their key processes. Common mechanism of fault-tolerant is mainly realised based on static structural redundancy principle, but the redundancy in hardware layer costs high and is complex in execution, while the redundancy in application layer is of low versatile. This paper proposes a fault-tolerant mechanism and policy based on process redundancy, which constructs dual-modular redundancy or multi-modular redundancy on key application processes. The method employs the means of interprocess synchronisation to ensure the operation of redundancy processes based on the same execution logic, supervises the system and makes corresponding error handing on different faults. Compared with traditional fault-tolerant way, the process fault-tolerant management system has the characteristics of high versatility and low cost, can effectively ensure high reliability of the system with less performance lost and avoid the complexity in hardware customisation at the same time, while it keeps the transparent to applications and users as well.%高端容错计算机主要应用于银行、电信等关键领域中,对于系统失效极其敏感,保证系统关键进程的可靠性至关重要.常见的容错机制主要依据静态结构冗余原理实现,然而硬件层的冗余成本很高且实现复杂,应用软件层的冗余则不具有通用性.提出一种基于进程冗余的容错机制和策略,对关键进程构造双模冗余或多模冗余,采用进程间同步等手段确保冗余进程按照同样的执行逻辑运行,监控系统并对不同的错误进行相应的错误处理.与传统的容错方式相比,进程容错管理系统具有通用性高、成本低等特点,能在较小的性能损耗下有效地保证系统的高可靠性,同时避

  9. A Fault-Tolerant Architecture for Parlay Application Server

    Institute of Scientific and Technical Information of China (English)

    LI Yong-ping; CHEN Jun-liang

    2004-01-01

    As the value-added service providing system in the Next-Generation Networks (NGN), Application Servers (AS) are required to provide the carrier-class reliability. To increase the reliability of AS, the fault-tolerant technology is often adopted. This paper proposes a fault-tolerant architecture for AS against single-point faults. The result of analysis shows that the architecture has a good reliability and is easily extendable. Such an advantage is attributed to a kind of special fault-tolerant design, which is different from others in that two Service Logic Program (SLP) instances do not only provide backups to each other, but also share them in the service traffic.

  10. Computer aided reliability, availability, and safety modeling for fault-tolerant computer systems with commentary on the HARP program

    Science.gov (United States)

    Shooman, Martin L.

    1991-01-01

    Many of the most challenging reliability problems of our present decade involve complex distributed systems such as interconnected telephone switching computers, air traffic control centers, aircraft and space vehicles, and local area and wide area computer networks. In addition to the challenge of complexity, modern fault-tolerant computer systems require very high levels of reliability, e.g., avionic computers with MTTF goals of one billion hours. Most analysts find that it is too difficult to model such complex systems without computer aided design programs. In response to this need, NASA has developed a suite of computer aided reliability modeling programs beginning with CARE 3 and including a group of new programs such as: HARP, HARP-PC, Reliability Analysts Workbench (Combination of model solvers SURE, STEM, PAWS, and common front-end model ASSIST), and the Fault Tree Compiler. The HARP program is studied and how well the user can model systems using this program is investigated. One of the important objectives will be to study how user friendly this program is, e.g., how easy it is to model the system, provide the input information, and interpret the results. The experiences of the author and his graduate students who used HARP in two graduate courses are described. Some brief comparisons were made with the ARIES program which the students also used. Theoretical studies of the modeling techniques used in HARP are also included. Of course no answer can be any more accurate than the fidelity of the model, thus an Appendix is included which discusses modeling accuracy. A broad viewpoint is taken and all problems which occurred in the use of HARP are discussed. Such problems include: computer system problems, installation manual problems, user manual problems, program inconsistencies, program limitations, confusing notation, long run times, accuracy problems, etc.

  11. Fault Tolerant Parallel Filters Based On Bch Codes

    Directory of Open Access Journals (Sweden)

    K.Mohana Krishna

    2015-04-01

    Full Text Available Digital filters are used in signal processing and communication systems. In some cases, the reliability of those systems is critical, and fault tolerant filter implementations are needed. Over the years, many techniques that exploit the filters’ structure and properties to achieve fault tolerance have been proposed. As technology scales, it enables more complex systems that incorporate many filters. In those complex systems, it is common that some of the filters operate in parallel, for example, by applying the same filter to different input signals. Recently, a simple technique that exploits the presence of parallel filters to achieve multiple fault tolerance has been presented. In this brief, that idea is generalized to show that parallel filters can be protected using Bose– Chaudhuri–Hocquenghem codes (BCH in which each filter is the equivalent of a bit in a traditional ECC. This new scheme allows more efficient protection when the number of parallel filters is large.

  12. Fault-Tolerant Mechanism of the Distributed Cluster Computers"

    Institute of Scientific and Technical Information of China (English)

    SHANG Yizi; JIN Yang; WU Baosheng

    2007-01-01

    The distributed system with high performance and stability is commonly adopted in large scale scientific and engineering computing. In this paper, we discuss a fault-tolerant mechanism under Linux circumstance to improve the fault-tolerant ability of the system, namely a scheme and frame to form the stable computing platform. In terms of the structure and function of the distributed system, active list and file invocation strategies are employed in the task management. System multilevel fault-tolerance can be achieved by repeated processes in a single node and task migration on multi-nodes. Manager node agent introduced in this paper administrates the nodes using the list, disposes of the tasks according to the nodes'performance, and hence, to be able to make full use of the cluster resources. An evaluation method is proposed to appraise the performance. The analyzed results show the usefulness of the scheme proposed except for some additional overhead of memory consumption.

  13. Scheduling of Fault-Tolerant Embedded Systems with Soft and Hard Timing Constraints

    DEFF Research Database (Denmark)

    Izosimov, Viacheslav; Pop, Paul; Eles, Petru;

    2008-01-01

    fails or completes, incurs an unacceptable overhead. Thus, we use a quasi-static scheduling strategy, where a set of schedules is synthesized off-line and, at run time, the scheduler will select the right schedule based on the occurrence of faults and the actual execution times of processes...

  14. A continuous-time semi-markov bayesian belief network model for availability measure estimation of fault tolerant systems

    Directory of Open Access Journals (Sweden)

    Márcio das Chagas Moura

    2008-08-01

    Full Text Available In this work it is proposed a model for the assessment of availability measure of fault tolerant systems based on the integration of continuous time semi-Markov processes and Bayesian belief networks. This integration results in a hybrid stochastic model that is able to represent the dynamic characteristics of a system as well as to deal with cause-effect relationships among external factors such as environmental and operational conditions. The hybrid model also allows for uncertainty propagation on the system availability. It is also proposed a numerical procedure for the solution of the state probability equations of semi-Markov processes described in terms of transition rates. The numerical procedure is based on the application of Laplace transforms that are inverted by the Gauss quadrature method known as Gauss Legendre. The hybrid model and numerical procedure are illustrated by means of an example of application in the context of fault tolerant systems.Neste trabalho, é proposto um modelo baseado na integração entre processos semi-Markovianos e redes Bayesianas para avaliação da disponibilidade de sistemas tolerantes à falha. Esta integração resulta em um modelo estocástico híbrido o qual é capaz de representar as características dinâmicas de um sistema assim como tratar as relações de causa e efeito entre fatores externos tais como condições ambientais e operacionais. Além disso, o modelo híbrido permite avaliar a propagação de incerteza sobre a disponibilidade do sistema. É também proposto um procedimento numérico para a solução das equações de probabilidade de estado de processos semi-Markovianos descritos por taxas de transição. Tal procedimento numérico é baseado na aplicação de transformadas de Laplace que são invertidas pelo método de quadratura Gaussiana conhecido como Gauss Legendre. O modelo híbrido e procedimento numérico são ilustrados por meio de um exemplo de aplicação no contexto de

  15. Research and application of Fault-Tolerance techniques in electric locomotive system%电力机车系统容错技术研究及应用

    Institute of Scientific and Technical Information of China (English)

    陈勇; 颜罡; 陈哲

    2014-01-01

    Fault-Tolerance is one of critical methods providing safety and reliability. In the paper,it presents the basic Fault-Tol-erance techniques in locomotive system, and describes detailly how to realize Fault-Tolerance techniques in each subsystem of electric locomotive.%容错技术是保证系统运行安全性和可靠性的关键手段之一。介绍了电力机车系统中常用的容错技术及其基本原理,并以和谐系列机车为例详细阐述了电力机车各子系统容错技术的实现方法。

  16. SIFT - Multiprocessor architecture for Software Implemented Fault Tolerance flight control and avionics computers

    Science.gov (United States)

    Forman, P.; Moses, K.

    1979-01-01

    A brief description of a SIFT (Software Implemented Fault Tolerance) Flight Control Computer with emphasis on implementation is presented. A multiprocessor system that relies on software-implemented fault detection and reconfiguration algorithms is described. A high level reliability and fault tolerance is achieved by the replication of computing tasks among processing units.

  17. A droplet routing technique for fault-tolerant digital microfluidic devices

    NARCIS (Netherlands)

    Zhang, Xiao; Proosdij, van Frits; Kerkhoff, Hans G.

    2008-01-01

    Abstract—Efficient droplet routing is one of the key approaches for realizing fault-tolerant microfluidic biochips. It requires that run-time diagnosis and fault recovery can be made possible in such systems. This paper describes a droplet routing technique for a fault-tolerant digital microfluidic

  18. Learning Fault-tolerant Speech Parsing with SCREEN

    CERN Document Server

    Wermter, S; Wermter, Stefan; Weber, Volker

    1994-01-01

    This paper describes a new approach and a system SCREEN for fault-tolerant speech parsing. SCREEEN stands for Symbolic Connectionist Robust EnterprisE for Natural language. Speech parsing describes the syntactic and semantic analysis of spontaneous spoken language. The general approach is based on incremental immediate flat analysis, learning of syntactic and semantic speech parsing, parallel integration of current hypotheses, and the consideration of various forms of speech related errors. The goal for this approach is to explore the parallel interactions between various knowledge sources for learning incremental fault-tolerant speech parsing. This approach is examined in a system SCREEN using various hybrid connectionist techniques. Hybrid connectionist techniques are examined because of their promising properties of inherent fault tolerance, learning, gradedness and parallel constraint integration. The input for SCREEN is hypotheses about recognized words of a spoken utterance potentially analyzed by a spe...

  19. Adding Fault Tolerance to NPB Benchmarks Using ULFM

    Energy Technology Data Exchange (ETDEWEB)

    Parchman, Zachary W [Tennessee Technological University (TTU); Vallee, Geoffroy R [ORNL; Naughton III, Thomas J [ORNL; Engelmann, Christian [ORNL; Bernholdt, David E [ORNL; Scott, Stephen L [Tennessee Technological University (TTU)

    2016-01-01

    In the world of high-performance computing, fault tolerance and application resilience are becoming some of the primary concerns because of increasing hardware failures and memory corruptions. While the research community has been investigating various options, from system-level solutions to application-level solutions, standards such as the Message Passing Interface (MPI) are also starting to include such capabilities. The current proposal for MPI fault tolerant is centered around the User-Level Failure Mitigation (ULFM) concept, which provides means for fault detection and recovery of the MPI layer. This approach does not address application-level recovery, which is currently left to application developers. In this work, we present a mod- ification of some of the benchmarks of the NAS parallel benchmark (NPB) to include support of the ULFM capabilities as well as application-level strategies and mechanisms for application-level failure recovery. As such, we present: (i) an application-level library to checkpoint and restore data, (ii) extensions of NPB benchmarks for fault tolerance based on different strategies, (iii) a fault injection tool, and (iv) some preliminary results that show the impact of such fault tolerant strategies on the application execution.

  20. Interactive animation of fault-tolerant parallel algorithms

    Energy Technology Data Exchange (ETDEWEB)

    Apgar, S.W.

    1992-02-01

    Animation of algorithms makes understanding them intuitively easier. This paper describes the software tool Raft (Robust Animator of Fault Tolerant Algorithms). The Raft system allows the user to animate a number of parallel algorithms which achieve fault tolerant execution. In particular, we use it to illustrate the key Write-All problem. It has an extensive user-interface which allows a choice of the number of processors, the number of elements in the Write-All array, and the adversary to control the processor failures. The novelty of the system is that the interface allows the user to create new on-line adversaries as the algorithm executes.

  1. Design Approach for Fault Tolerance in FPGA Architecture

    Directory of Open Access Journals (Sweden)

    Ms. Shweta S. Meshram

    2011-03-01

    Full Text Available Failures of nano-metric technologies owing to defects and shrinking process tolerances give rise tosignificant challenges for IC testing. In recent years the application space of reconfigurable devices hasgrown to include many platforms with a strong need for fault tolerance. While these systems frequentlycontain hardware redundancy to allow for continued operation in the presence of operational faults, theneed to recover faulty hardware and return it to full functionality quickly and efficiently is great. Inaddition to providing functional density, FPGAs provide a level of fault tolerance generally not found inmask-programmable devices by including the capability to reconfigure around operational faults in thefield. Reliability and process variability are serious issues for FPGAs in the future. With advancement inprocess technology, the feature size is decreasing which leads to higher defect densities, moresophisticated techniques at increased costs are required to avoid defects. If nano-technology fabricationare applied the yield may go down to zero as avoiding defect during fabrication will not be a feasibleoption Hence, feature architecture have to be defect tolerant. In regular structure like FPGA, redundancyis commonly used for fault tolerance. In this work we present a solution in which configuration bit-streamof FPGA is modified by a hardware controller that is present on the chip itself. The technique usesredundant device for replacing faulty device and increases the yield.

  2. Fault Tolerant Control for Civil Structures Based on LMI Approach

    Directory of Open Access Journals (Sweden)

    Chunxu Qu

    2013-01-01

    Full Text Available The control system may lose the performance to suppress the structural vibration due to the faults in sensors or actuators. This paper designs the filter to perform the fault detection and isolation (FDI and then reforms the control strategy to achieve the fault tolerant control (FTC. The dynamic equation of the structure with active mass damper (AMD is first formulated. Then, an estimated system is built to transform the FDI filter design problem to the static gain optimization problem. The gain is designed to minimize the gap between the estimated system and the practical system, which can be calculated by linear matrix inequality (LMI approach. The FDI filter is finally used to isolate the sensor faults and reform the FTC strategy. The efficiency of FDI and FTC is validated by the numerical simulation of a three-story structure with AMD system with the consideration of sensor faults. The results show that the proposed FDI filter can detect the sensor faults and FTC controller can effectively tolerate the faults and suppress the structural vibration.

  3. A modified NARMAX model-based self-tuner with fault tolerance for unknown nonlinear stochastic hybrid systems with an input-output direct feed-through term.

    Science.gov (United States)

    Tsai, Jason S-H; Hsu, Wen-Teng; Lin, Long-Guei; Guo, Shu-Mei; Tann, Joseph W

    2014-01-01

    A modified nonlinear autoregressive moving average with exogenous inputs (NARMAX) model-based state-space self-tuner with fault tolerance is proposed in this paper for the unknown nonlinear stochastic hybrid system with a direct transmission matrix from input to output. Through the off-line observer/Kalman filter identification method, one has a good initial guess of modified NARMAX model to reduce the on-line system identification process time. Then, based on the modified NARMAX-based system identification, a corresponding adaptive digital control scheme is presented for the unknown continuous-time nonlinear system, with an input-output direct transmission term, which also has measurement and system noises and inaccessible system states. Besides, an effective state space self-turner with fault tolerance scheme is presented for the unknown multivariable stochastic system. A quantitative criterion is suggested by comparing the innovation process error estimated by the Kalman filter estimation algorithm, so that a weighting matrix resetting technique by adjusting and resetting the covariance matrices of parameter estimate obtained by the Kalman filter estimation algorithm is utilized to achieve the parameter estimation for faulty system recovery. Consequently, the proposed method can effectively cope with partially abrupt and/or gradual system faults and input failures by the fault detection.

  4. Fault Tolerant System for Sparse Traffic Grooming in Optical WDM Mesh Networks Using Combiner Queue

    Directory of Open Access Journals (Sweden)

    Sandip R. Shinde

    2016-03-01

    Full Text Available Queuing theory is an important concept in current internet technology. As the requirement of bandwidth goes on increasing it is necessary to use optical communication for transfer of data. Optical communication at backbone network requires various devices for traffic grooming. The cost of these devices is very high which leads to increase in the cost of network. One of the solutions to this problem is to have sparse traffic grooming in optical WDM mesh network. Sparse traffic grooming allows only few nodes in the network as grooming node (G-node. These G-nodes has the grooming capability and other nodes are simple nodes where traffic grooming is not possible. The grooming nodes are the special nodes which has high cost. The possibility of faults at such a node, or link failure is high. Resolving such faults and providing efficient network is very important. So we have importance of such survivable sparse traffic grooming network. Queuing theory helps to improve the result of network and groom the traffic in the network. The paper focuses on the improvement in performance of the backbone network and reduction in blocking probability. To achieve the goals of the work we have simulated the model. The main contribution is to use survivability on the sparse grooming network and use of combiner queues at each node. It has observed that Combiner queuing alone does the job of minimizing blocking probability and balancing the load over the network. The model is not only cost effective but also increases the performance of network and minimizes the call blocking probability

  5. Fault-tolerant search algorithms reliable computation with unreliable information

    CERN Document Server

    Cicalese, Ferdinando

    2013-01-01

    Why a book on fault-tolerant search algorithms? Searching is one of the fundamental problems in computer science. Time and again algorithmic and combinatorial issues originally studied in the context of search find application in the most diverse areas of computer science and discrete mathematics. On the other hand, fault-tolerance is a necessary ingredient of computing. Due to their inherent complexity, information systems are naturally prone to errors, which may appear at any level - as imprecisions in the data, bugs in the software, or transient or permanent hardware failures. This book pr

  6. Fault-tolerance for MPI Codes on Computational Clusters

    OpenAIRE

    Hagen, Knut Imar

    2007-01-01

    This thesis focuses on fault-tolerance for MPI codes on computational clusters. When an application runs on a very large cluster with thousands of processors, there is likely that a process crashes due to a hardware or software failure. Fault-tolerance is the ability of a system to respond gracefully to an unexpected hardware or software failure. A test application which is meant to run for several weeks on several nodes is used in this thesis. The application is a seismic MPI application, w...

  7. Rule-based fault-tolerant flight control

    Science.gov (United States)

    Handelman, Dave

    1988-01-01

    Fault tolerance has always been a desirable characteristic of aircraft. The ability to withstand unexpected changes in aircraft configuration has a direct impact on the ability to complete a mission effectively and safely. The possible synergistic effects of combining techniques of modern control theory, statistical hypothesis testing, and artificial intelligence in the attempt to provide failure accommodation for aircraft are investigated. This effort has resulted in the definition of a theory for rule based control and a system for development of such a rule based controller. Although presented here in response to the goal of aircraft fault tolerance, the rule based control technique is applicable to a wide range of complex control problems.

  8. Fault Tolerant Control of Wind Turbines

    DEFF Research Database (Denmark)

    Odgaard, Peter Fogh; Stoustrup, Jakob; Kinnaert, Michel

    2013-01-01

    This paper presents a test benchmark model for the evaluation of fault detection and accommodation schemes. This benchmark model deals with the wind turbine on a system level, and it includes sensor, actuator, and system faults, namely faults in the pitch system, the drive train, the generator......, and the converter system. Since it is a system-level model, converter and pitch system models are simplified because these are controlled by internal controllers working at higher frequencies than the system model. The model represents a three-bladed pitch-controlled variable-speed wind turbine with a nominal power...... for the FDI design....

  9. Passive Fault tolerant Control of an Inverted Double Pendulum

    DEFF Research Database (Denmark)

    Niemann, H.; Stoustrup, Jakob

    2003-01-01

    A passive fault tolerant control scheme is suggested, in which a nominal controller is augmented with an additional block, which guarantees stability and performance after the occurrence of a fault. The method is based on the Youla parameterization, which requires the nominal controller to be imp...... to be implemented in the observer based form. The proposed method is applied to a double inverted pendulum system, for which an H controller has been designed and verified in a lap setup. In this case study, the fault is a degradation of the tacho loop....

  10. Research on Fault Tolerant Scheduling Algorithms of Web Cluster Based on Probability

    Institute of Scientific and Technical Information of China (English)

    LIU An-feng; CHEN Zhi-gang; LONG Guo-ping

    2005-01-01

    Aiming at the soft real-time fault tolerant demand of critical web applications at present, such as E-commerce, a new fault tolerant scheduling algorithm based on probability is proposed. To achieve fault tolerant scheduling,the primary/slave backup technology is applied on the basis of task's self similar accessing characteristics, when the primary task completed successfully, the resources allocated for the slave task are reclaimed, thus advancing system's efficiency.Experimental results demonstrate on the premise of satisfying system's certain fault tolerant probability, task's schedulabilistic probability is improved, especially, the higher task's self similar degree is, the more obviously the utilization of system resources is enhanced.

  11. Fault Detection for Shipboard Monitoring and Decision Support Systems

    DEFF Research Database (Denmark)

    Lajic, Zoran; Nielsen, Ulrik Dam

    2009-01-01

    In this paper a basic idea of a fault-tolerant monitoring and decision support system will be explained. Fault detection is an important part of the fault-tolerant design for in-service monitoring and decision support systems for ships. In the paper, a virtual example of fault detection will be p...

  12. Electrical Steering of Vehicles - Fault-tolerant Analysis and Design

    DEFF Research Database (Denmark)

    Blanke, Mogens; Thomsen, Jesper Sandberg

    2006-01-01

    solutions and still meet strict requirements to functional safety. The paper applies graph-based analysis of functional system structure to find a novel fault-tolerant architecture for an electrical steering where a dedicated AC-motor design and cheap voltage measurements ensure ability to detect all...

  13. Design methodology for fault-tolerant control of advanced driver assistance systems

    NARCIS (Netherlands)

    Gietelink, O.J.; Ploeg, J.; Schutter, B. de; Verhaegen, M.H.G.

    2003-01-01

    The objective of this project is to develop a methodology for the design, testing, evaluation and implementation of control systems for Advanced Driver Assistance Systems (ADAS). Examples of ADAS are collision avoidance systems, lane departure warning systems, pre-crash sensing, and adaptive cruise

  14. Design of Test Articles and Monitoring System for the Characterization of HIRF Effects on a Fault-Tolerant Computer Communication System

    Science.gov (United States)

    Torres-Pomales, Wilfredo; Malekpour, Mahyar R.; Miner, Paul S.; Koppen, Sandra V.

    2008-01-01

    This report describes the design of the test articles and monitoring systems developed to characterize the response of a fault-tolerant computer communication system when stressed beyond the theoretical limits for guaranteed correct performance. A high-intensity radiated electromagnetic field (HIRF) environment was selected as the means of injecting faults, as such environments are known to have the potential to cause arbitrary and coincident common-mode fault manifestations that can overwhelm redundancy management mechanisms. The monitors generate stimuli for the systems-under-test (SUTs) and collect data in real-time on the internal state and the response at the external interfaces. A real-time health assessment capability was developed to support the automation of the test. A detailed description of the nature and structure of the collected data is included. The goal of the report is to provide insight into the design and operation of these systems, and to serve as a reference document for use in post-test analyses.

  15. Steps toward fault-tolerant quantum chemistry.

    Energy Technology Data Exchange (ETDEWEB)

    Taube, Andrew Garvin

    2010-05-01

    Developing quantum chemistry programs on the coming generation of exascale computers will be a difficult task. The programs will need to be fault-tolerant and minimize the use of global operations. This work explores the use a task-based model that uses a data-centric approach to allocate work to different processes as it applies to quantum chemistry. After introducing the key problems that appear when trying to parallelize a complicated quantum chemistry method such as coupled-cluster theory, we discuss the implications of that model as it pertains to the computational kernel of a coupled-cluster program - matrix multiplication. Also, we discuss the extensions that would required to build a full coupled-cluster program using the task-based model. Current programming models for high-performance computing are fault-intolerant and use global operations. Those properties are unsustainable as computers scale to millions of CPUs; instead one must recognize that these systems will be hierarchical in structure, prone to constant faults, and global operations will be infeasible. The FAST-OS HARE project is introducing a scale-free computing model to address these issues. This model is hierarchical and fault-tolerant by design, allows for the clean overlap of computation and communication, reducing the network load, does not require checkpointing, and avoids the complexity of many HPC runtimes. Development of an algorithm within this model requires a change in focus from imperative programming to a data-centric approach. Quantum chemistry (QC) algorithms, in particular electronic structure methods, are an ideal test bed for this computing model. These methods describe the distribution of electrons in a molecule, which determine the properties of the molecule. The computational cost of these methods is high, scaling quartically or higher in the size of the molecule, which is why QC applications are major users of HPC resources. The complexity of these algorithms means that

  16. OPTIMAL DESIGN ALGORITHM FOR FAULT TOLERANT INFORMATION SYSTEMS USED FOR PROCESSING ELECTRONIC MEDICAL RECORDS

    Directory of Open Access Journals (Sweden)

    P. V. Melyushin

    2014-01-01

    Full Text Available The paper considers problems on designing of medical information systems and proposes an approach to creation of a highly reliable automated system for processing electronic medical records on the basis of file allocation optimization in the network nodes. A mathematical model has been developed for optimal distribution of the files in the network nodes and an experimental investigation of two schemes of medical information systems has been executed in the paper.

  17. Nonlinear, Adaptive and Fault-tolerant Control for Electro-hydraulic Servo Systems

    OpenAIRE

    Choux, Martin; Blanke, Mogens; Hovland, Geir

    2011-01-01

    Fluid power systems have been in use since 1795 with the rst hydraulic press patented by Joseph Bramah and today form the basis of many industries. Electro hydraulic servo systems are uid power systems controlled in closed-loop. They transform reference input signals into a set of movements in hydraulic actuators (cylinders or motors) by the means of hydraulic uid under pressure. With the development of computing power and control techniques during the last few decades, they are used increasi...

  18. Implementations of a four-level mechanical architecture for fault-tolerant robots

    International Nuclear Information System (INIS)

    This paper describes a fault tolerant mechanical architecture with four levels devised and implemented in concert with NASA (Tesar, D. and Sreevijayan, D., Four-level fault tolerance in manipulator design for space operations. In First Int. Symp. Measurement and Control in Robotics (ISMCR '90), Houston, Texas, 20-22 June 1990.) Subsequent work has clarified and revised the architecture. The four levels proceed from fault tolerance at the actuator level, to fault tolerance via in-parallel chains, to fault tolerance using serial kinematic redundancy, and finally to the fault tolerance multiple arm systems provide. This is a subsumptive architecture because each successive layer can incorporate the fault tolerance provided by all layers beneath. For instance a serially-redundant robot can incorporate dual fault-tolerant actuators. Redundant systems provide the fault tolerance, but the guiding principle of this architecture is that functional redundancies actively increase the performance of the system. Redundancies do not simply remain dormant until needed. This paper includes specific examples of hardware and/or software implementation at all four levels

  19. System-Level Development of Fault-Tolerant Distributed Aero-Engine Control Architecture Project

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA's vision for an "intelligent engine" will be realized with the development of a truly distributed control system and reliable smart transducer node components;...

  20. Fault-tolerant Control of Discrete-time LPV systems using Virtual Actuators and Sensors

    DEFF Research Database (Denmark)

    Tabatabaeipour, Mojtaba; Stoustrup, Jakob; Bak, Thomas

    2015-01-01

    , it transforms the output of the controller for the faulty system such that the stability and performance goals are preserved. Input-to-state stabilizing LPV gains of the virtual actuator and sensor are obtained by solving linear matrix inequalities (LMIs). We show that separate design of these gains guarantees...... the plant and the nominal controller. The reconfiguration block is realized by an LPV virtual actuator and an LPV virtual sensor. Its goal is to transform the signals from the faulty system such that its behavior is similar to that of the nominal system from the viewpoint of the controller. Furthermore...... the input-to-state stability (ISS) of the closed-loop reconfigured system. Moreover, we obtain performances in terms of the ISS gains for the virtual actuator, the virtual sensor and their interconnection. Minimizing these performances is formulated as convex optimization problems subject to LMI constraints...

  1. A Structural Analysis Method Formulation for Fault-tolerant Control System Design

    DEFF Research Database (Denmark)

    Izadi-Zamanabadi, Roozbeh; Staroswiecki, M

    2000-01-01

    An analysis of structural model representation has been used to extract available inherent redundant information in the system. The paper presents a refined structured model representation based on bipartite directed graph definition and the necessary condition for sensor fusion based...

  2. Internal Leakage Fault Detection and Tolerant Control of Single-Rod Hydraulic Actuators

    Directory of Open Access Journals (Sweden)

    Jianyong Yao

    2014-01-01

    Full Text Available The integration of internal leakage fault detection and tolerant control for single-rod hydraulic actuators is present in this paper. Fault detection is a potential technique to provide efficient condition monitoring and/or preventive maintenance, and fault tolerant control is a critical method to improve the safety and reliability of hydraulic servo systems. Based on quadratic Lyapunov functions, a performance-oriented fault detection method is proposed, which has a simple structure and is prone to implement in practice. The main feature is that, when a prescribed performance index is satisfied (even a slight fault has occurred, there is no fault alarmed; otherwise (i.e., a severe fault has occurred, the fault is detected and then a fault tolerant controller is activated. The proposed tolerant controller, which is based on the parameter adaptive methodology, is also prone to realize, and the learning mechanism is simple since only the internal leakage is considered in parameter adaptation and thus the persistent exciting (PE condition is easily satisfied. After the activation of the fault tolerant controller, the control performance is gradually recovered. Simulation results on a hydraulic servo system with both abrupt and incipient internal leakage fault demonstrate the effectiveness of the proposed fault detection and tolerant control method.

  3. Event-Triggered Faults Tolerant Control for Stochastic Systems with Time Delays

    Directory of Open Access Journals (Sweden)

    Ling Huang

    2016-01-01

    Full Text Available This paper is concerned with the state-feedback controller design for stochastic networked control systems (NCSs with random actuator failures and transmission delays. Firstly, an event-triggered scheme is introduced to optimize the performance of the stochastic NCSs. Secondly, stochastic NCSs under event-triggered scheme are modeled as stochastic time-delay systems. Thirdly, some less conservative delay-dependent stability criteria in terms of linear matrix inequalities for the codesign of both the controller gain and the trigger parameters are obtained by using delay-decomposition technique and convex combination approach. Finally, a numerical example is provided to show the less sampled data transmission and less conservatism of the proposed theory.

  4. Self Fault-Tolerance of Protocols: A Case Study

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The prerequisite for the existing protocols' correctness is that protocols can be normally operated under the normal conditions, rather than dealing with abnormal conditions.In other words, protocols with the fault-tolerance can not be provided when some fault occurs. This paper discusses the self fault-tolerance of protocols. It describes some concepts and methods for achieving self fault tolerance of protocols. Meanwhile, it provides a case study, investigates a typical protocol that does not satisfy the self fault-tolerance, and gives a new redesign version of this existing protocol using the proposed approach.

  5. Fault tolerant attitude control for small unmanned aircraft systems equipped with an airflow sensor array

    International Nuclear Information System (INIS)

    Inspired by sensing strategies observed in birds and bats, a new attitude control concept of directly using real-time pressure and shear stresses has recently been studied. It was shown that with an array of onboard airflow sensors, small unmanned aircraft systems can promptly respond to airflow changes and improve flight performances. In this paper, a mapping function is proposed to compute aerodynamic moments from the real-time pressure and shear data in a practical and computationally tractable formulation. Since many microscale airflow sensors are embedded on the small unmanned aircraft system surface, it is highly possible that certain sensors may fail. Here, an adaptive control system is developed that is robust to sensor failure as well as other numerical mismatches in calculating real-time aerodynamic moments. The advantages of the proposed method are shown in the following simulation cases: (i) feedback pressure and wall shear data from a distributed array of 45 airflow sensors; (ii) 50% failure of the symmetrically distributed airflow sensor array; and (iii) failure of all the airflow sensors on one wing. It is shown that even if 50% of the airflow sensors have failures, the aircraft is still stable and able to track the attitude commands. (paper)

  6. Fault tolerant attitude control for small unmanned aircraft systems equipped with an airflow sensor array.

    Science.gov (United States)

    Shen, H; Xu, Y; Dickinson, B T

    2014-01-01

    Inspired by sensing strategies observed in birds and bats, a new attitude control concept of directly using real-time pressure and shear stresses has recently been studied. It was shown that with an array of onboard airflow sensors, small unmanned aircraft systems can promptly respond to airflow changes and improve flight performances. In this paper, a mapping function is proposed to compute aerodynamic moments from the real-time pressure and shear data in a practical and computationally tractable formulation. Since many microscale airflow sensors are embedded on the small unmanned aircraft system surface, it is highly possible that certain sensors may fail. Here, an adaptive control system is developed that is robust to sensor failure as well as other numerical mismatches in calculating real-time aerodynamic moments. The advantages of the proposed method are shown in the following simulation cases: (i) feedback pressure and wall shear data from a distributed array of 45 airflow sensors; (ii) 50% failure of the symmetrically distributed airflow sensor array; and (iii) failure of all the airflow sensors on one wing. It is shown that even if 50% of the airflow sensors have failures, the aircraft is still stable and able to track the attitude commands. PMID:25405953

  7. Development and evaluation of a fault-tolerant multiprocessor (FTMP) computer. Volume 1: FTMP principles of operation

    Science.gov (United States)

    Smith, T. B., Jr.; Lala, J. H.

    1983-01-01

    The basic organization of the fault tolerant multiprocessor, (FTMP) is that of a general purpose homogeneous multiprocessor. Three processors operate on a shared system (memory and I/O) bus. Replication and tight synchronization of all elements and hardware voting is employed to detect and correct any single fault. Reconfiguration is then employed to repair a fault. Multiple faults may be tolerated as a sequence of single faults with repair between fault occurrences.

  8. Communication and Agreement Abstractions for Fault-Tolerant Asynchronous Distributed Systems

    CERN Document Server

    Raynal, Michel

    2010-01-01

    Understanding distributed computing is not an easy task. This is due to the many facets of uncertainty one has to cope with and master in order to produce correct distributed software. Considering the uncertainty created by asynchrony and process crash failures in the context of message-passing systems, the book focuses on the main abstractions that one has to understand and master in order to be able to produce software with guaranteed properties. These fundamental abstractions are communication abstractions that allow the processes to communicate consistently (namely the register abstraction

  9. Stable Fault-tolerance Control for a Class of Networked Control Systems%一类网络化控制系统的稳定容错控制

    Institute of Scientific and Technical Information of China (English)

    孔德明; 方华京

    2005-01-01

    In this paper, we use the matrix measure technique to study stable fault-tolerance control of networked control systems. State feedback networked control systems with the network-induced delay, parameter uncertainties, sensor failures and actuator failures are considered. State feedback gain K is designed for any invariant delay τ, and some theorems and sufficient conditions for stable fault-tolerance control are given. Example is presented to illustrate the effectiveness of these theorems.

  10. Superior model for fault tolerance computation in designing nano-sized circuit systems

    Energy Technology Data Exchange (ETDEWEB)

    Singh, N. S. S., E-mail: narinderjit@petronas.com.my; Muthuvalu, M. S., E-mail: msmuthuvalu@gmail.com [Fundamental and Applied Sciences Department, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, Perak (Malaysia); Asirvadam, V. S., E-mail: vijanth-sagayan@petronas.com.my [Electrical and Electronics Engineering Department, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, Perak (Malaysia)

    2014-10-24

    As CMOS technology scales nano-metrically, reliability turns out to be a decisive subject in the design methodology of nano-sized circuit systems. As a result, several computational approaches have been developed to compute and evaluate reliability of desired nano-electronic circuits. The process of computing reliability becomes very troublesome and time consuming as the computational complexity build ups with the desired circuit size. Therefore, being able to measure reliability instantly and superiorly is fast becoming necessary in designing modern logic integrated circuits. For this purpose, the paper firstly looks into the development of an automated reliability evaluation tool based on the generalization of Probabilistic Gate Model (PGM) and Boolean Difference-based Error Calculator (BDEC) models. The Matlab-based tool allows users to significantly speed-up the task of reliability analysis for very large number of nano-electronic circuits. Secondly, by using the developed automated tool, the paper explores into a comparative study involving reliability computation and evaluation by PGM and, BDEC models for different implementations of same functionality circuits. Based on the reliability analysis, BDEC gives exact and transparent reliability measures, but as the complexity of the same functionality circuits with respect to gate error increases, reliability measure by BDEC tends to be lower than the reliability measure by PGM. The lesser reliability measure by BDEC is well explained in this paper using distribution of different signal input patterns overtime for same functionality circuits. Simulation results conclude that the reliability measure by BDEC depends not only on faulty gates but it also depends on circuit topology, probability of input signals being one or zero and also probability of error on signal lines.

  11. Superior model for fault tolerance computation in designing nano-sized circuit systems

    International Nuclear Information System (INIS)

    As CMOS technology scales nano-metrically, reliability turns out to be a decisive subject in the design methodology of nano-sized circuit systems. As a result, several computational approaches have been developed to compute and evaluate reliability of desired nano-electronic circuits. The process of computing reliability becomes very troublesome and time consuming as the computational complexity build ups with the desired circuit size. Therefore, being able to measure reliability instantly and superiorly is fast becoming necessary in designing modern logic integrated circuits. For this purpose, the paper firstly looks into the development of an automated reliability evaluation tool based on the generalization of Probabilistic Gate Model (PGM) and Boolean Difference-based Error Calculator (BDEC) models. The Matlab-based tool allows users to significantly speed-up the task of reliability analysis for very large number of nano-electronic circuits. Secondly, by using the developed automated tool, the paper explores into a comparative study involving reliability computation and evaluation by PGM and, BDEC models for different implementations of same functionality circuits. Based on the reliability analysis, BDEC gives exact and transparent reliability measures, but as the complexity of the same functionality circuits with respect to gate error increases, reliability measure by BDEC tends to be lower than the reliability measure by PGM. The lesser reliability measure by BDEC is well explained in this paper using distribution of different signal input patterns overtime for same functionality circuits. Simulation results conclude that the reliability measure by BDEC depends not only on faulty gates but it also depends on circuit topology, probability of input signals being one or zero and also probability of error on signal lines

  12. Error Mitigation of Point-to-Point Communication for Fault-Tolerant Computing

    Science.gov (United States)

    Akamine, Robert L.; Hodson, Robert F.; LaMeres, Brock J.; Ray, Robert E.

    2011-01-01

    Fault tolerant systems require the ability to detect and recover from physical damage caused by the hardware s environment, faulty connectors, and system degradation over time. This ability applies to military, space, and industrial computing applications. The integrity of Point-to-Point (P2P) communication, between two microcontrollers for example, is an essential part of fault tolerant computing systems. In this paper, different methods of fault detection and recovery are presented and analyzed.

  13. Diagnosis and Fault-tolerant Control, 3rd Edition

    DEFF Research Database (Denmark)

    Blanke, Mogens; Kinnaert, Michel; Lunze, Jan;

    The book presents effective model-based analysis and design methods for fault diagnosis and fault-tolerant control. Architectural and structural models are used to analyse the propagation of the fault through the process, to test the fault detectability and to find the redundancies in the process...

  14. Algorithm-dependent fault tolerance for distributed computing

    Energy Technology Data Exchange (ETDEWEB)

    P. D. Hough; M. e. Goldsby; E. J. Walsh

    2000-02-01

    Large-scale distributed systems assembled from commodity parts, like CPlant, have become common tools in the distributed computing world. Because of their size and diversity of parts, these systems are prone to failures. Applications that are being run on these systems have not been equipped to efficiently deal with failures, nor is there vendor support for fault tolerance. Thus, when a failure occurs, the application crashes. While most programmers make use of checkpoints to allow for restarting of their applications, this is cumbersome and incurs substantial overhead. In many cases, there are more efficient and more elegant ways in which to address failures. The goal of this project is to develop a software architecture for the detection of and recovery from faults in a cluster computing environment. The detection phase relies on the latest techniques developed in the fault tolerance community. Recovery is being addressed in an application-dependent manner, thus allowing the programmer to take advantage of algorithmic characteristics to reduce the overhead of fault tolerance. This architecture will allow large-scale applications to be more robust in high-performance computing environments that are comprised of clusters of commodity computers such as CPlant and SMP clusters.

  15. Universal Fault-Tolerant Computation on Decoherence-Free Subspaces

    CERN Document Server

    Bacon, D J; Lidar, D A; Whaley, K B

    2000-01-01

    A general scheme to perform universal quantum computation fault-tolerantly within decoherence-free subspaces (DFSs) of a system's Hilbert space is derived. This scheme leads to the first fault-tolerant realization of universal quantum computation on DFSs with the properties that (i) only one- and two-qubit interactions are required, and (ii) the system remains within the DFS throughout the entire implementation of a quantum gate. We show explicitly how to perform universal computation on clusters of the four-qubit DFS encoding one logical qubit each under "collective decoherence" (qubit-permutation-invariant system-bath coupling). Our results have immediate relevance to a number of proposed quantum computer implementations, in particular those in which the internal system Hamiltonian is of the Heisenberg type, such as spin-spin coupled quantum dots.

  16. COMPREHENSIVE EVALUATION OF FAULT-TOLERANT PROPERTIES OF REDUNDANT ROBOTS

    Institute of Scientific and Technical Information of China (English)

    ZHAO Jing; FENG Dengdian

    2008-01-01

    When a redundant robot performs a fault-tolerant operation for locked joint failures, its fault tolerant properties should include dexterity and sudden change of joint velocity at the moment of locking failed joints and the dexterity during the post-failure. Firstly three fault-tolerant indexes, reduced condition number, sudden change of relative joint velocity and centrality are proposed, which can comprehensively evaluate the kinematical performance of a redundant robot during its entire fault-tolerant operations. Then, the influence of the initial postures of robot's end-effector on these fault-tolerant indexes is analyzed with a planar robot and a spatial robot. Simulation results show that for a given task the joint trajectory with the best comprehensive effect of fault tolerance can be determined by optimizing the initial posture of a robot.

  17. Employment of Reduced Precision Redundancy for Fault Tolerant FPGA Applications

    OpenAIRE

    Sullivan, Margaret A.; Loomis, Herschel H.; Ross, Alan A.

    2009-01-01

    2009 17th IEEE Symposium on Field Programmable Custom Computing Machines This research explores the employment of Reduced Precision Redundancy (RPR) as a powersaving alternative to traditional Triple Modular Redundancy (TMR). This paper focuses on the details of RPR implementation and the effect of RPR fault tolerance on the performance of spacecraft systems. RPR-protected system performance is evaluated using a signal-to-noise ratio analogy developed with MATLAB an...

  18. Fault tolerance in Hadoop MapReduce implementation

    OpenAIRE

    Cogorno, Matías; Rey, Javier; Nesmachnow, Sergio

    2013-01-01

    This document reports the advances on exploring and understanding the fault tolerance mechanisms in Hadoop MapReduce. A description of the current fault tolerance features existing in Hadoop is provided, along with a review of related works on the topic. Finally, the document describes some relevant proposals about fault tolerance worth considering to implement in Hadoop within the PERMARE project in order to provide support for pervasive computing environments.

  19. Design study of Software-Implemented Fault-Tolerance (SIFT) computer

    Science.gov (United States)

    Wensley, J. H.; Goldberg, J.; Green, M. W.; Kutz, W. H.; Levitt, K. N.; Mills, M. E.; Shostak, R. E.; Whiting-Okeefe, P. M.; Zeidler, H. M.

    1982-01-01

    Software-implemented fault tolerant (SIFT) computer design for commercial aviation is reported. A SIFT design concept is addressed. Alternate strategies for physical implementation are considered. Hardware and software design correctness is addressed. System modeling and effectiveness evaluation are considered from a fault-tolerant point of view.

  20. Fault Diagnosis and Fault-Tolerant Control of Uncertain Robot Manipulators Using High-Order Sliding Mode

    Directory of Open Access Journals (Sweden)

    Mien Van

    2016-01-01

    Full Text Available A robust fault diagnosis and fault-tolerant control (FTC system for uncertain robot manipulators without joint velocity measurement is presented. The actuator faults and robot manipulator component faults are considered. The proposed scheme is designed via an active fault-tolerant control strategy by combining a fault diagnosis scheme based on a super-twisting third-order sliding mode (STW-TOSM observer with a robust super-twisting second-order sliding mode (STW-SOSM controller. Compared to the existing FTC methods, the proposed FTC method can accommodate not only faults but also uncertainties, and it does not require a velocity measurement. In addition, because the proposed scheme is designed based on the high-order sliding mode (HOSM observer/controller strategy, it exhibits fast convergence, high accuracy, and less chattering. Finally, computer simulation results for a PUMA560 robot are obtained to verify the effectiveness of the proposed strategy.

  1. A Blueprint for a Topologically Fault-tolerant Quantum Computer

    CERN Document Server

    Bonderson, Parsa; Freedman, Michael; Nayak, Chetan

    2010-01-01

    The advancement of information processing into the realm of quantum mechanics promises a transcendence in computational power that will enable problems to be solved which are completely beyond the known abilities of any "classical" computer, including any potential non-quantum technologies the future may bring. However, the fragility of quantum states poses a challenging obstacle for realization of a fault-tolerant quantum computer. The topological approach to quantum computation proposes to surmount this obstacle by using special physical systems -- non-Abelian topologically ordered phases of matter -- that would provide intrinsic fault-tolerance at the hardware level. The so-called "Ising-type" non-Abelian topological order is likely to be physically realized in a number of systems, but it can only provide a universal gate set (a requisite for quantum computation) if one has the ability to perform certain dynamical topology-changing operations on the system. Until now, practical methods of implementing thes...

  2. Fault-tolerant distributed mass storage for LHC computing

    CERN Document Server

    Wiebalck, A; Lindenstruth, V; Stinbeck, T M

    2003-01-01

    In this paper we present the concept and first prototyping results of a modular fault-tolerant distributed mass storage architecture for large Linux PC clusters as they are deployed by the upcoming particle physics experiments. The device masquerading technique using an Enhanced Network Block Device (ENBD) enables local RAID over remote disks as the key concept of the ClusterRAID system. The block level interface to remote files, partitions or disks provided by the ENBD makes it possible to use the standard Linux software RAID to add fault-tolerance to the system. Preliminary performance measurements indicate that the latency is comparable to a local hard drive. With four disks throughput rates of up to 55MB/s were achieved with first prototypes for a RAIDO setup, and about 40M/s for a RAID5 setup. (29 refs).

  3. On the Transition Improvement of EV or HEV Induction Motor Propulsion Sensor Fault-Tolerant Controller

    OpenAIRE

    Tabbache, Bekheira; Benbouzid, Mohamed; Kheloui, Abdelaziz

    2010-01-01

    International audience This technical paper deals with the transition performance improvement of a sensor fault-tolerant controller devoted to Electric (EV) or Hybrid Electric Vehicles (HEV). Indeed, improvements are brought over a previously developed technique that exhibit abrupt changes in the torque if a sensor fault is detected and after a transition from a control technique to another one [1]. The Fault-Tolerant Control (FTC) system firstly concerns the sliding mode control technique...

  4. Learning Fault-tolerant Speech Parsing with SCREEN

    OpenAIRE

    Wermter, Stefan; Weber, Volker

    1994-01-01

    This paper describes a new approach and a system SCREEN for fault-tolerant speech parsing. SCREEEN stands for Symbolic Connectionist Robust EnterprisE for Natural language. Speech parsing describes the syntactic and semantic analysis of spontaneous spoken language. The general approach is based on incremental immediate flat analysis, learning of syntactic and semantic speech parsing, parallel integration of current hypotheses, and the consideration of various forms of speech related errors. T...

  5. Fault tolerant control with torque limitation based on fault mode for ten-phase permanent magnet synchronous motor

    Institute of Scientific and Technical Information of China (English)

    Guo Hong; Xu Jinquan

    2015-01-01

    This paper proposes a novel fault tolerant control with torque limitation based on the fault mode for the ten-phase permanent magnet synchronous motor (PMSM) under various open-circuit and short-circuit fault conditions, which includes the optimal torque control and the torque limitation control based on the fault mode. The optimal torque control is adopted to guarantee the ripple-free electromagnetic torque operation for the ten-phase motor system under the post-fault condition. Furthermore, we systematically analyze the load capacity of the ten-phase motor system under different fault modes. And a torque limitation control approach based on the fault mode is proposed, which was not available earlier. This approach is able to ensure the safety operation of the faulted motor system in long operating time without causing the overheat fault. The simulation result confirms that the proposed fault tolerant control for the ten-phase motor system is able to guarantee the ripple-free electromagnetic torque and the safety operation in long operating time under the normal and fault conditions.

  6. Fault tolerant control with torque limitation based on fault mode for ten-phase permanent magnet synchronous motor

    Directory of Open Access Journals (Sweden)

    Guo Hong

    2015-10-01

    Full Text Available This paper proposes a novel fault tolerant control with torque limitation based on the fault mode for the ten-phase permanent magnet synchronous motor (PMSM under various open-circuit and short-circuit fault conditions, which includes the optimal torque control and the torque limitation control based on the fault mode. The optimal torque control is adopted to guarantee the ripple-free electromagnetic torque operation for the ten-phase motor system under the post-fault condition. Furthermore, we systematically analyze the load capacity of the ten-phase motor system under different fault modes. And a torque limitation control approach based on the fault mode is proposed, which was not available earlier. This approach is able to ensure the safety operation of the faulted motor system in long operating time without causing the overheat fault. The simulation result confirms that the proposed fault tolerant control for the ten-phase motor system is able to guarantee the ripple-free electromagnetic torque and the safety operation in long operating time under the normal and fault conditions.

  7. FAIL-MPI: How fault-tolerant is fault-tolerant MPI ?

    OpenAIRE

    Hérault, Thomas; Hoarau, William; Lemarinier, Pierre; Rodriguez, Eric; Tixeuil, Sébastien

    2006-01-01

    One of the topics of paramount importance in the development of Cluster and Grid middleware is the impact of faults since their occurrence probability in a Grid infrastructure and in large-scale distributed system is actually very high. MPI (Message Passing Interface) is a popular abstraction for programming distributed computation applications. FAIL is an abstract language for fault occurrence description capable of expressing complex and realistic fault scenarios. In this paper, we investig...

  8. Design of Six Channel ABS System with Fault Tolerant Technology%基于容错技术的六通道ABS系统设计

    Institute of Scientific and Technical Information of China (English)

    苗晓锋; 王胜

    2012-01-01

    采用容错技术,通过2个MCU之间的CAN通讯的消息应答机制,设计了具有容错功能的六通道ABS系统.2个MCU同时接收和处理来自车轮传感器的轮速信号和故障诊断信号.如果主控MCU处于正常工作状态的时候,另一个MCU则处于备用状态,且实时地通过CAN总线和主控进行通讯,对其进行监控.如果主控MCU处于故障状态的时候,备用MCU立即接替主控MCU进行工作,以提高六通道ABS系统的可靠性.%The paper design the six channels ABS system with the fault tolerant technology, which is realized fault tolerant function by message response mechanism of CAN communication between the two MCU. The two MCU receive and process the speed signal and fault diagnosis signal which is come from the wheel speed sensor. If main control MCU is good, the other MCU is in the standby state. At the same time, the main control MCU and standby MCU are communicated by CAN bus timely and inspect each other. If main control MCU is in fault,the standby MCU is work to substitute the main control MCU immediately. The paper proposed design method improvement the reliability of six channels ABS system.

  9. Runtime Instrumentation of SystemC/TLM2 Interfaces for Fault Tolerance Requirements Verification in Software Cosimulation

    Directory of Open Access Journals (Sweden)

    Antonio da Silva

    2014-01-01

    Full Text Available This paper presents the design of a SystemC transaction level modelling wrapping library that can be used for the assertion of system properties, protocol compliance, or fault injection. The library uses C++ virtual table hooks as a dynamic binary instrumentation technique to inline wrappers in the TLM2 transaction path. This technique can be applied after the elaboration phase and needs neither source code modifications nor recompilation of the top level SystemC modules. The proposed technique has been successfully applied to the robustness verification of the on-board boot software of the Instrument Control Unit of the Solar Orbiter’s Energetic Particle Detector.

  10. Fault Tolerance in ZigBee Wireless Sensor Networks

    Science.gov (United States)

    Alena, Richard; Gilstrap, Ray; Baldwin, Jarren; Stone, Thom; Wilson, Pete

    2011-01-01

    Wireless sensor networks (WSN) based on the IEEE 802.15.4 Personal Area Network standard are finding increasing use in the home automation and emerging smart energy markets. The network and application layers, based on the ZigBee 2007 PRO Standard, provide a convenient framework for component-based software that supports customer solutions from multiple vendors. This technology is supported by System-on-a-Chip solutions, resulting in extremely small and low-power nodes. The Wireless Connections in Space Project addresses the aerospace flight domain for both flight-critical and non-critical avionics. WSNs provide the inherent fault tolerance required for aerospace applications utilizing such technology. The team from Ames Research Center has developed techniques for assessing the fault tolerance of ZigBee WSNs challenged by radio frequency (RF) interference or WSN node failure.

  11. Fault-tolerance techniques for SRAM-based FPGAs

    CERN Document Server

    Kastensmidt, Fernanda Lima; Reis, Ricardo

    2006-01-01

    Fault-tolerance in integrated circuits is no longer the exclusive concern of space designers or highly-reliable applications engineers. Today, designers of many next-generation products must cope with reduced margin noises. The continuous evolution of fabrication technology of semiconductor components – shrinking transistor geometry, power supply, speed, and logic density – has significantly reduced the reliability of very deep submicron integrated circuits, in face of various internal and external sources of noise. Field Programmable Gate Arrays (FPGAs), customizable by SRAM cells, are the latest advance in the integrated circuit evolution: millions of memory cells to implement the logic, embedded memories, routing, and embedded microprocessors cores. These re-programmable systems-on-chip platforms must be fault-tolerant to cope with current requirements.

  12. Active Fault Tolerant Control for Ultrasonic Piezoelectric Motor

    Science.gov (United States)

    Boukhnifer, Moussa

    2012-07-01

    Ultrasonic piezoelectric motor technology is an important system component in integrated mechatronics devices working on extreme operating conditions. Due to these constraints, robustness and performance of the control interfaces should be taken into account in the motor design. In this paper, we apply a new architecture for a fault tolerant control using Youla parameterization for an ultrasonic piezoelectric motor. The distinguished feature of proposed controller architecture is that it shows structurally how the controller design for performance and robustness may be done separately which has the potential to overcome the conflict between performance and robustness in the traditional feedback framework. A fault tolerant control architecture includes two parts: one part for performance and the other part for robustness. The controller design works in such a way that the feedback control system will be solely controlled by the proportional plus double-integral PI2 performance controller for a nominal model without disturbances and H∞ robustification controller will only be activated in the presence of the uncertainties or an external disturbances. The simulation results demonstrate the effectiveness of the proposed fault tolerant control architecture.

  13. Analysis of a cascaded multilevel inverter with fault-tolerant control

    Directory of Open Access Journals (Sweden)

    Jesús Aguayo Alquicira

    2011-08-01

    Full Text Available Cascaded multilevel inverters are widely used in industry for speed control of induction motors and, even when the converters’ operation is highly reliable, several faults can occur, leading to poor engine performance or even causing the whole system to stop. It is desirable to keep the system operational when a failure occurs, even when degraded, and implementing fault-tolerant systems are thus a good choice. This paper presents a general strategy for fault-tolerant control in a 7-level cascaded multilevel inverter (the faults are in semiconductor devices; the paper includes simulation and experimental results to validate the method.

  14. Robust fault-tolerant control for wing flutter under actuator failure

    Institute of Scientific and Technical Information of China (English)

    Gao Mingzhou; Cai Guoping

    2016-01-01

    Many control laws, such as optimal controller and classical controller, have seen their applications to suppressing the aeroelastic vibrations of the aeroelastic system. However, those con-trol laws may not work effectively if the aeroelastic system involves actuator faults. In the current study for wing flutter of reentry vehicle, the effect of actuator faults on wing flutter system is rarely considered and few of the fault-tolerant control problems are taken into account. In this paper, we use the radial basis function neural network and the finite-time H∞adaptive fault-tolerant control technique to deal with the flutter problem of wings, which is affected by actuator faults, actuator saturation, parameter uncertainties and external disturbances. The theory of this article includes the modeling of wing flutter and fault-tolerant controller design. The stability of the finite-time adaptive fault-tolerant controller is theoretically proved. Simulation results indicate that the designed fault-tolerant flutter controller can effectively deal with the faults in the flutter system and can promptly suppress the wing flutter as well.

  15. Robust fault-tolerant control for wing flutter under actuator failure

    Directory of Open Access Journals (Sweden)

    Gao Mingzhou

    2016-08-01

    Full Text Available Many control laws, such as optimal controller and classical controller, have seen their applications to suppressing the aeroelastic vibrations of the aeroelastic system. However, those control laws may not work effectively if the aeroelastic system involves actuator faults. In the current study for wing flutter of reentry vehicle, the effect of actuator faults on wing flutter system is rarely considered and few of the fault-tolerant control problems are taken into account. In this paper, we use the radial basis function neural network and the finite-time H∞ adaptive fault-tolerant control technique to deal with the flutter problem of wings, which is affected by actuator faults, actuator saturation, parameter uncertainties and external disturbances. The theory of this article includes the modeling of wing flutter and fault-tolerant controller design. The stability of the finite-time adaptive fault-tolerant controller is theoretically proved. Simulation results indicate that the designed fault-tolerant flutter controller can effectively deal with the faults in the flutter system and can promptly suppress the wing flutter as well.

  16. Fault-tolerant and efficient parallel computation. Doctoral thesis

    Energy Technology Data Exchange (ETDEWEB)

    Shvartsman, A.A.

    1992-05-01

    Recent advances in computer technology made parallel machines a reality. Massively parallel systems use many general-purpose, inexpensive processing elements to attain computation speed-ups comparable to or better than those achieved by expensive, specialized machines with a small number of fast processors. In such setting, however, one would expect to see an increased number of processor failures attributable to hardware or software. This may eliminate the potential advantage of parallel computation. We believe that this presents a reliability bottleneck that is among fundamental problems in parallel computation. We investigate algorithmic ways of introducing fault-tolerance in multiprocessors under the constraint of preserving efficiency. This research demonstrates how in certain models of parallel computation it is possible to combine efficiency and fault-tolerance. We show that in the models we study, it is possible to develop efficient parallel algorithms without concern for fault-tolerance, and then correctly and efficiently execute these algorithms on parallel machines whose processors are subject to arbitrary dynamic failstop errors. By ensuring efficient executions for any patterns of failures, the efficiency is also maintained when failures are infrequent, or when the expected number of failures is small.

  17. Fault diagnosis and fault-tolerant control and guidance for aerospace vehicles from theory to application

    CERN Document Server

    Zolghadri, Ali; Cieslak, Jerome; Efimov, Denis; Goupil, Philippe

    2014-01-01

    Fault Diagnosis and Fault-Tolerant Control and Guidance for Aerospace demonstrates the attractive potential of recent developments in control for resolving such issues as improved flight performance, self-protection and extended life of structures. Importantly, the text deals with a number of practically significant considerations: tuning, complexity of design, real-time capability, evaluation of worst-case performance, robustness in harsh environments, and extensibility when development or adaptation is required. Coverage of such issues helps to draw the advanced concepts arising from academic research back towards the technological concerns of industry. Initial coverage of basic definitions and ideas and a literature review gives way to a treatment of important electrical flight control system failures: the oscillatory failure case, runaway, and jamming. Advanced fault detection and diagnosis for linear and nonlinear systems are described. Lastly recovery strategies appropriate to remaining acuator/sensor/c...

  18. Guaranteed Cost Fault-tolerant Control of Networked Control Systems with Short Output Delay and Short Control Delay Based on State Observer

    Directory of Open Access Journals (Sweden)

    Xiaomao Huang

    2013-04-01

    Full Text Available Supposing that the sensor and controller nodes were time-driven and the actuator node was event-driven, the problem of integrity against sensor failures for the networked control systems with short output delay and short control delay was discussed based on observer. The state observer of the system according to the time-delay compensation strategy was designed. Then, considering possible sensor failures, an augmented mathematic model for the networked control systems based on observer was developed. In terms of the given quadratic performance index function, the integrity condition of the system was given and the designs for guaranteed cost fault-tolerant controller and observer were presented respectively by using the cooperative design approach of the controller and observer and the approach of bilinear matrix inequalities. Finally, a numerical simulation example demonstrated the conclusions are feasible and effective. The proposed control method meets the requirements in industrial networked control systems.

  19. Architecting Fault Tolerance with Exception Handling: Verification and Validation

    Institute of Scientific and Technical Information of China (English)

    Patrick H. S. Brito; Rogério de Lemos; Cecília M. F. Rubira; Eliane Martins

    2009-01-01

    When building dependable systems by integrating untrusted software components that were not originally designed to interact with each other, it is likely the occurrence of architectural mismatches related to assumptions in their failure behaviour. These mismatches, if not prevented during system design, have to be tolerated during runtime. This paper presents an architectural abstraction based on exception handling for structuring fault-tolerant software systems.This abstraction comprises several components and connectors that promote an existing untrusted software element into an idealised fault-tolerant architectural element. Moreover, it is considered in the context of a rigorous software development approach based on formal methods for representing the structure and behaviour of the software architecture. The proposed approach relies on a formal specification and verification for analysing exception propagation, and verifying important dependability properties, such as deadlock freedom, and scenarios of architectural reconfiguration. The formal models are automatically generated using model transformation from UML diagrams: component diagram representing the system structure, and sequence diagrams representing the system behaviour. Finally, the formal models are also used for generating unit and integration test cases that are used for assessing the correctness of the source code. The feasibility of the proposed architectural approach was evaluated on an embedded critical case study.

  20. Hybrid system modeling and fault diagnosis of fault tolerant inverter%新型容错逆变器的混杂系统建模与故障诊断

    Institute of Scientific and Technical Information of China (English)

    李宁; 李颖晖; 朱喜华; 雷洪利; 俞佳

    2012-01-01

    考虑到传统开关函数模型只对逆变电路的控制变迁进行分析而无法描述电路的条件变迁,容易丢失电路在条件变迁过程中所表现出的故障信息,从而影响故障诊断的实时性和准确性.电力电子电路是典型的混杂系统,文章建立了一种新型容错逆变器的混杂系统模型,在此基础上提出了故障事件辨识向量的概念,并将其应用于逆变器故障的分析,仅通过故障事件辨识向量对逆变电路变迁过程中的故障事件进行辨识来完成故障诊断,对于电路变迁过程中的正常事件辨识不予考虑,减少了控制系统的数据处理量,提高了故障诊断的实时性和可靠性,实验验证了所提方法的可行性和有效性.%The traditional switch function model of inverters could analyze the control change of inverters, but could not be used to describe conditions change. The fault information contained in conditions change may be lost, and the real-time performance and accuracy of fault diagnosis will be reduced,Power electronic circuits were typical hybrid system. The paper established the hybrid system model for a fault-tolerant inverter, and then put forward the concept of incidents identification vector,which was applied to analyze the fault of inverter. It finished the fault diagnosis only through the identification of fault events by incidents identification vector, which could reduce the data capacity of control system, and the real time performance and reliability of fault diagnosis were improved- The simulation and experiment results show the feasibility and validity of the proposed method.

  1. Fault Detection and Isolation and Fault Tolerant Control of Wind Turbines Using Set-Valued Observers

    DEFF Research Database (Denmark)

    Casau, Pedro; Rosa, Paulo Andre Nobre; Tabatabaeipour, Seyed Mojtaba;

    2012-01-01

    account process disturbances, uncertainty and sensor noise. The FTC strategy takes advantage of the proposed FDI algorithm, enabling the controller reconfiguration shortly after fault events. Additionally, a robust controller is designed so as to increase the wind turbine's performance during low severity......Research on wind turbine Operations & Maintenance (O&M) procedures is critical to the expansion of Wind Energy Conversion systems (WEC). In order to reduce O&M costs and increase the lifespan of the turbine, we study the application of Set-Valued Observers (SVO) to the problem of Fault Detection...... and Isolation (FDI) and Fault Tolerant Control (FTC) of wind turbines, by taking advantage of the recent advances in SVO theory for model invalidation. A simple wind turbine model is presented along with possible faulty scenarios. The FDI algorithm is built on top of the described model, taking into...

  2. Full Tolerant Archiving System

    Science.gov (United States)

    Knapic, C.; Molinaro, M.; Smareglia, R.

    2013-10-01

    The archiving system at the Italian center for Astronomical Archives (IA2) manages data from external sources like telescopes, observatories, or surveys and handles them in order to guarantee preservation, dissemination, and reliability, in most cases in a Virtual Observatory (VO) compliant manner. A metadata model dynamic constructor and a data archive manager are new concepts aimed at automatizing the management of different astronomical data sources in a fault tolerant environment. The goal is a full tolerant archiving system, nevertheless complicated by the presence of various and time changing data models, file formats (FITS, HDF5, ROOT, PDS, etc.) and metadata content, even inside the same project. To avoid this unpleasant scenario a novel approach is proposed in order to guarantee data ingestion, backward compatibility, and information preservation.

  3. Fusion of Built in Test (BIT) Technologies with Embeddable Fault Tolerant Techniques for Power System and Drives in Space Exploration Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Impact Technologies has proposed development of an effective prognostic and fault accommodation system for critical DC power systems including PV systems. Overall...

  4. Hybrid fault tolerance techniques to detect transient faults in embedded processors

    CERN Document Server

    Azambuja, José Rodrigo; Becker, Jürgen

    2014-01-01

    This book describes fault tolerance techniques based on software and hardware to create hybrid techniques. They are able to reduce overall performance degradation and increase error detection when associated with applications implemented in embedded processors. Coverage begins with an extensive discussion of the current state-of-the-art in fault tolerance techniques. The authors then discuss the best trade-off between software-based and hardware-based techniques and introduce novel hybrid techniques. Proposed techniques increase existing fault detection rates up to 100%, while maintaining low performance overheads in area and application execution time. • Discusses the effects of radiation on modern integrated circuits; • Provides a comprehensive overview of state-of-the art fault tolerance techniques based on software, hardware, and hybrid techniques; • Introduces novel hybrid fault tolerance techniques for reconfigurable FPGAs and ASICs; • Performs fault injection campaigns by simulation, bitstream ...

  5. Fault-Tolerant Approach for Modular Multilevel Converters under Submodule Faults

    DEFF Research Database (Denmark)

    Deng, Fujin; Tian, Yanjun; Zhu, Rongwu;

    2016-01-01

    The modular multilevel converter (MMC) is attractive for medium- or high-power applications because of the advantages of its high modularity, availability, and high power quality. The fault-tolerant operation is one of the important issues for the MMC. This paper proposed a fault-tolerant approach...... for the MMC under submodule (SM) faults. The characteristic of the MMC with arms containing different number of healthy SMs under faults is analyzed. Based on the characteristic, the proposed approach can effectively keep the MMC operation as normal under SM faults. It can effectively improve the MMC...

  6. A New Fault-tolerant Switched Reluctance Motor with reliable fault detection capability

    DEFF Research Database (Denmark)

    Lu, Kaiyuan

    2014-01-01

    For reliable fault detection, often, search coils are used in many fault-tolerant drives. The search coils occupy extra slot space. They are normally open-circuited and are not used for torque production. This degrades the motor performance, increases the cost and manufacture complexity. A new...... Fault-Tolerant Switched Reluctance (FTSR) motor is proposed in this paper. A unique feature of this special design is that it allows use of the unexcited phase coils as search coils for fault detection. Therefore this new motor has all the advantages of using search coils for reliable fault detection...

  7. Adaptive Fault Tolerant Execution of Multi-Robot Missions using Behavior Trees

    OpenAIRE

    Colledanchise, Michele; Marzinotto, Alejandro; Dimarogonas, Dimos V.; Ögren, Petter

    2015-01-01

    Multi-robot teams offer possibilities of improved performance and fault tolerance, compared to single robot solutions. In this paper, we show how to realize those possibilities when starting from a single robot system controlled by a Behavior Tree (BT). By extending the single robot BT to a multi-robot BT, we are able to combine the fault tolerant properties of the BT, in terms of built-in fallbacks, with the fault tolerance inherent in multi-robot approaches, in terms of a faulty robot being...

  8. Fault-Tolerant Software Design for the Distributed Superviso ry Control Systems%分布式微机监控系统的软件容错设计

    Institute of Scientific and Technical Information of China (English)

    王劭伯; 郭谋发

    2000-01-01

    The fault-tolerant techniques are important meth ods to improve the reliability of computer control systems.Taking some practica l examples as the background materials,this paper discusses the fault-tolerant s oftware techniques for the distributed computer supervisory control systems and the applications of artificial intelligence to the fault-tolerant design.%容错技术是提高计算机控制系统可靠性的一种重要 方法。以若干工程实例作为背景材料,讨论分布式微机监控系统的软件容错设计技术,探讨 人工智能技术在容错设计中的应用。

  9. 某型飞机燃油系统容错控制策略研究%Fault-tolerant Control Strategy Research of the Fuel System of a Type Airplane

    Institute of Scientific and Technical Information of China (English)

    张晶; 魏东; 赵智姝

    2011-01-01

    本文介绍了容错控制的基本概念,在此基础上对容错控制方法进行了分析,并给出了某型飞机燃油系统的容错控制策略,提高了燃油系统的可靠性,改善了飞机的飞行品质.%This paper introduces the basic concept of fault-tolerant control, on the basis, analyzes fault-tolerant control methods, and gives the fault-tolerant control strategy of the fuel system of a type airplane, which improved the reliability of fuel system and improved the aircraft's quality.

  10. 应用信度分配的模糊CMAC实现非线性系统的容错控制%Fault-tolerant Control of Nonlinear System Using Credit Assign Fuzzy CMAC

    Institute of Scientific and Technical Information of China (English)

    朱大奇; 孔敏

    2006-01-01

    The adaptive fault-tolerant control scheme of dynamic nonlinear system based on the credit assigned fuzzy CMAC neural network is presented. The proposed learning approach uses the learned times of addressed hypercubes as the credibility, the amounts of correcting errors are proportional to the inversion of the learned times of addressed hypercubes. With this idea, the learning speed can indeed be improved. Based on the improved CMAC learning approach and using the sliding control technique, the effective control law reconfiguration strategy is presented. The system stability and performance are analyzed under failure scenarios. The numerical simulation demonstrates the effectiveness of the improved CMAC algorithm and the proposed fault-tolerant controller.

  11. Design of passive fault-tolerant controllers of a quadrotor based on sliding mode theory

    Directory of Open Access Journals (Sweden)

    Merheb Abdel-Razzak

    2015-09-01

    Full Text Available Abstract In this paper, sliding mode control is used to develop two passive fault tolerant controllers for an AscTec Pelican UAV quadrotor. In the first approach, a regular sliding mode controller (SMC augmented with an integrator uses the robustness property of variable structure control to tolerate partial actuator faults. The second approach is a cascaded sliding mode controller with an inner and outer SMC loops. In this configuration, faults are tolerated in the fast inner loop controlling the velocity system. Tuning the controllers to find the optimal values of the sliding mode controller gains is made using the ecological systems algorithm (ESA, a biologically inspired stochastic search algorithm based on the natural equilibrium of animal species. The controllers are tested using SIMULINK in the presence of two different types of actuator faults, partial loss of motor power affecting all the motors at once, and partial loss of motor speed. Results of the quadrotor following a continuous path demonstrated the effectiveness of the controllers, which are able to tolerate a significant number of actuator faults despite the lack of hardware redundancy in the quadrotor system. Tuning the controller using a faulty system improves further its ability to afford more severe faults. Simulation results show that passive schemes reserve their important role in fault tolerant control and are complementary to active techniques

  12. Planning the deployment of fault-tolerant wireless sensor networks

    OpenAIRE

    Sitanayah, Lanny

    2013-01-01

    Since Wireless Sensor Networks (WSNs) are subject to failures, fault-tolerance becomes an important requirement for many WSN applications. Fault-tolerance can be enabled in different areas of WSN design and operation, including the Medium Access Control (MAC) layer and the initial topology design. To be robust to failures, a MAC protocol must be able to adapt to traffic fluctuations and topology dynamics. We design ER-MAC that can switch from energy-efficient operation in norma...

  13. Fault-tolerant Sensor Fusion for Marine Navigation

    DEFF Research Database (Denmark)

    Blanke, Mogens

    2006-01-01

    Reliability of navigation data are critical for steering and manoeuvring control, and in particular so at high speed or in critical phases of a mission. Should faults occur, faulty instruments need be autonomously isolated and faulty information discarded. This paper designs a navigation solution...... events where the fault-tolerant sensor fusion provided uninterrupted navigation data despite temporal instrument defects...

  14. Fault tolerant wind speed estimator used in wind turbine controllers

    DEFF Research Database (Denmark)

    Odgaard, Peter Fogh; Stoustrup, Jakob

    2012-01-01

    Advanced control schemes can be used to optimize energy production and cost of energy in modern wind turbines. These control schemes most often rely on wind speed estimations. These designs of wind speed estimators are, however, not designed to be fault tolerant towards faults in the used sensors...

  15. SEIF: Secure and Efficient Intrusion Fault tolerant protocol for Wireless Sensor Networks

    OpenAIRE

    Ouadjaout, Abdelraouf; Challal, Yacine; Lasla, Noureddine; Bagaa, Mouloud

    2008-01-01

    In wireless sensor networks, reliability represents a design goal of a primary concern. To build a comprehensive reliable system, it is essential to consider node failures and intruder attacks as unavoidable phenomena. In this paper, we present a new intrusion-fault tolerant routing scheme offering a high level of reliability through a secure multi-path communication topology. Unlike existing intrusion-fault tolerant solutions, our protocol is based on a distributed and in-network verificatio...

  16. A Remote Characterization System and a fault-tolerant tracking system for subsurface mapping of buried waste sites

    International Nuclear Information System (INIS)

    This paper describes two closely related projects that will provide new technology for characterizing hazardous waste burial sites. The first project, a collaborative effort by five of the national laboratories, involves the development and demonstration of a remotely controlled site characterization system. The Remote Characterization System (RCS) includes a unique low-signature survey vehicle, a base station, radio telemetry data links, satellite-based vehicle tracking, stereo vision, and sensors for noninvasive inspection of the surface and subsurface. The second project, conducted by the Idaho National Engineering Laboratory (INEL), involves the development of a position sensing system that can track a survey vehicle or instrument in the field. This system can coordinate updates at a rate of 200/s with an accuracy better than 0.1% of the distance separating the target and the sensor. It can employ acoustic or electromagnetic signals in a wide range of frequencies and can be operated as a passive or active device

  17. A Remote Characterization System and a fault-tolerant tracking system for subsurface mapping of buried waste sites

    Energy Technology Data Exchange (ETDEWEB)

    Sandness, G.A.; Bennett, D.W. [Pacific Northwest Lab., Richland, WA (United States); Martinson, L. [Westinghouse Idaho Nuclear Co., Inc., Idaho Falls, ID (United States); Bingham, D.N.; Anderson, A.A. [EG and G Idaho, Inc., Idaho Falls, ID (United States)

    1992-08-01

    This paper describes two closely related projects that will provide new technology for characterizing hazardous waste burial sites. The first project, a collaborative effort by five of the national laboratories, involves the development and demonstration of a remotely controlled site characterization system. The Remote Characterization System (RCS) includes a unique low-signature survey vehicle, a base station, radio telemetry data links, satellite-based vehicle tracking, stereo vision, and sensors for noninvasive inspection of the surface and subsurface. The second project, conducted by the Idaho National Engineering Laboratory (INEL), involves the development of a position sensing system that can track a survey vehicle or instrument in the field. This system can coordinate updates at a rate of 200/s with an accuracy better than 0.1% of the distance separating the target and the sensor. It can employ acoustic or electromagnetic signals in a wide range of frequencies and can be operated as a passive or active device.

  18. Particle Filter Based Fault-tolerant ROV Navigation using Hydro-acoustic Position and Doppler Velocity Measurements

    DEFF Research Database (Denmark)

    Zhao, Bo; Blanke, Mogens; Skjetne, Roger

    2012-01-01

    This paper presents a fault tolerant navigation system for a remotely operated vehicle (ROV). The navigation system uses hydro-acoustic position reference (HPR) and Doppler velocity log (DVL) measurements to achieve an integrated navigation. The fault tolerant functionality is based on a modied...... the ROV kinematic states, even when sensor failures appear frequently....

  19. A New Approach to Robust and Fault Tolerant Control

    Institute of Scientific and Technical Information of China (English)

    Kemin Zhou

    2005-01-01

    In this paper, we shall summarize a new approach to robust and fault tolerant control proposed recently by the author. This approach is based on a variation of all controller parametrization. This robust and fault-tolerant control design consists of two parts: a nominal performance controller and a robustness controller, and works in such a way that when a component (sensor,actuator, etc.) failure is detected, the controller structure is reconfigured by adding a robustness loop to compensate the fault. We shall illustrate how this strategy works under various situations.

  20. Design of passive fault-tolerant flight controller against actuator failures

    Directory of Open Access Journals (Sweden)

    Yu Xiang

    2015-02-01

    Full Text Available The problem of designing passive fault-tolerant flight controller is addressed when the normal and faulty cases are prescribed. First of all, the considered fault and fault-free cases are formed by polytopes. As considering that the safety of a post-fault system is directly related to the maximum values of physical variables in the system, peak-to-peak gain is selected to represent the relationships among the amplitudes of actuator outputs, system outputs, and reference commands. Based on the parameter dependent Lyapunov and slack methods, the passive fault-tolerant flight controllers in the absence/presence of system uncertainty for actuator failure cases are designed, respectively. Case studies of an airplane under actuator failures are carried out to validate the effectiveness of the proposed approach.

  1. Dynamic Output Feedback Based Active Decentralized Fault-Tolerant Control for Reconfigurable Manipulator with Concurrent Failures

    Directory of Open Access Journals (Sweden)

    Yuanchun Li

    2015-01-01

    Full Text Available The goal of this paper is to describe an active decentralized fault-tolerant control (ADFTC strategy based on dynamic output feedback for reconfigurable manipulators with concurrent actuator and sensor failures. Consider each joint module of the reconfigurable manipulator as a subsystem, and treat the fault as the unknown input of the subsystem. Firstly, by virtue of linear matrix inequality (LMI technique, the decentralized proportional-integral observer (DPIO is designed to estimate and compensate the sensor fault online; hereafter, the compensated system model could be derived. Then, the actuator fault is estimated similarly by another DPIO using LMI as well, and the sufficient condition of the existence of H∞ fault-tolerant controller in the dynamic output feedback is presented for the compensated system model. Furthermore, the dynamic output feedback controller is presented based on the estimation of actuator fault to realize active fault-tolerant control. Finally, two 3-DOF reconfigurable manipulators with different configurations are employed to verify the effectiveness of the proposed scheme in simulation. The main advantages of the proposed scheme lie in that it can handle the concurrent faults act on the actuator and sensor on the same joint module, as well as there is no requirement of fault detection and isolation process; moreover, it is more feasible to the modularity of the reconfigurable manipulator.

  2. Fault detection and isolation in systems with parametric faults

    DEFF Research Database (Denmark)

    Stoustrup, Jakob; Niemann, Hans Henrik

    1999-01-01

    The problem of fault detection and isolation of parametric faults is considered in this paper. A fault detection problem based on parametric faults are associated with internal parameter variations in the dynamical system. A fault detection and isolation method for parametric faults is formulated...

  3. Coordinated Fault-Tolerance for High-Performance Computing Final Project Report

    Energy Technology Data Exchange (ETDEWEB)

    Panda, Dhabaleswar Kumar [The Ohio State University; Beckman, Pete

    2011-07-28

    With the Coordinated Infrastructure for Fault Tolerance Systems (CIFTS, as the original project came to be called) project, our aim has been to understand and tackle the following broad research questions, the answers to which will help the HEC community analyze and shape the direction of research in the field of fault tolerance and resiliency on future high-end leadership systems. Will availability of global fault information, obtained by fault information exchange between the different HEC software on a system, allow individual system software to better detect, diagnose, and adaptively respond to faults? If fault-awareness is raised throughout the system through fault information exchange, is it possible to get all system software working together to provide a more comprehensive end-to-end fault management on the system? What are the missing fault-tolerance features that widely used HEC system software lacks today that would inhibit such software from taking advantage of systemwide global fault information? What are the practical limitations of a systemwide approach for end-to-end fault management based on fault awareness and coordination? What mechanisms, tools, and technologies are needed to bring about fault awareness and coordination of responses on a leadership-class system? What standards, outreach, and community interaction are needed for adoption of the concept of fault awareness and coordination for fault management on future systems? Keeping our overall objectives in mind, the CIFTS team has taken a parallel fourfold approach. Our central goal was to design and implement a light-weight, scalable infrastructure with a simple, standardized interface to allow communication of fault-related information through the system and facilitate coordinated responses. This work led to the development of the Fault Tolerance Backplane (FTB) publish-subscribe API specification, together with a reference implementation and several experimental implementations on top of

  4. Adaptive Fault Tolerance for Many-Core Based Space-Borne Computing

    Science.gov (United States)

    James, Mark; Springer, Paul; Zima, Hans

    2010-01-01

    This paper describes an approach to providing software fault tolerance for future deep-space robotic NASA missions, which will require a high degree of autonomy supported by an enhanced on-board computational capability. Such systems have become possible as a result of the emerging many-core technology, which is expected to offer 1024-core chips by 2015. We discuss the challenges and opportunities of this new technology, focusing on introspection-based adaptive fault tolerance that takes into account the specific requirements of applications, guided by a fault model. Introspection supports runtime monitoring of the program execution with the goal of identifying, locating, and analyzing errors. Fault tolerance assertions for the introspection system can be provided by the user, domain-specific knowledge, or via the results of static or dynamic program analysis. This work is part of an on-going project at the Jet Propulsion Laboratory in Pasadena, California.

  5. Fault-Tolerant Control Strategy for Steering Failures in Wheeled Planetary Rovers

    Directory of Open Access Journals (Sweden)

    Alexandre Carvalho Leite

    2012-01-01

    Full Text Available Fault-tolerant control design of wheeled planetary rovers is described. This paper covers all steps of the design process, from modeling/simulation to experimentation. A simplified contact model is used with a multibody simulation model and tuned to fit the experimental data. The nominal mode controller is designed to be stable and has its parameters optimized to improve tracking performance and cope with physical boundaries and actuator saturations. This controller was implemented in the real rover and validated experimentally. An impact analysis defines the repertory of faults to be handled. Failures in steering joints are chosen as fault modes; they combined six fault modes and a total of 63 possible configurations of these faults. The fault-tolerant controller is designed as a two-step procedure to provide alternative steering and reuse the nominal controller in a way that resembles a crab-like driving mode. Three fault modes are injected (one, two, and three failed steering joints in the real rover to evaluate the response of the nonreconfigured and reconfigured control systems in face of these faults. The experimental results justify our proposed fault-tolerant controller very satisfactorily. Additional concluding comments and an outlook summarize the lessons learned during the whole design process and foresee the next steps of the research.

  6. Reconfigurable Control of Input Affine Nonlinear Systems under Actuator Fault

    DEFF Research Database (Denmark)

    Tabatabaeipour, Mojtaba; Galeazzi, Roberto

    2015-01-01

    This paper proposes a fault tolerant control method for input-affine nonlinear systems using a nonlinear reconfiguration block (RB). The basic idea of the method is to insert the RB between the plant and the nominal controller such that fault tolerance is achieved without re-designing the nominal...

  7. Robust and Fault-Tolerant Linear Parameter-Varying Control of Wind Turbines

    DEFF Research Database (Denmark)

    Sloth, Christoffer; Esbensen, Thomas; Stoustrup, Jakob

    2011-01-01

    High performance and reliability are required for wind turbines to be competitive within the energy market. To capture their nonlinear behavior, wind turbines are often modeled using parameter-varying models. In this paper we design and compare multiple linear parameter-varying (LPV) controllers......, designed using a proposed method that allows the inclusion of both faults and uncertainties in the LPV controller design. We specifically consider a 4.8 MW, variable-speed, variable-pitch wind turbine model with a fault in the pitch system. We propose the design of a nominal controller (NC), handling...... the parameter variations along the nominal operating trajectory caused by nonlinear aerodynamics. To accommodate the fault in the pitch system, an active fault-tolerant controller (AFTC) and a passive fault-tolerant controller (PFTC) are designed. In addition to the nominal LPV controller, we also propose...

  8. Superconducting generator field winding design for high fault tolerance

    International Nuclear Information System (INIS)

    Development of rotating electrical machines with superconducting field windings is proceeding at numerous sites worldwide. The primary emphasis is on large turbine generators for application to power systems. The EPRI/Westinghouse 300 MVA superconducting generator program is directed towards demonstration of the technology in an actual utility environment for a long period of time. The concept of stability, in the case of superconducting generators, includes the traditional concepts of stability with respect to the electromechanical interactions and oscillations of the machine with the power system as well as the thermohydraulic stability of the cryogenic rotor and its helium supply system. Power system disturbances, such as faults, produce flow and pressure transients in the rotor cooling system. Depending upon the severity and time history of the disturbances, these transients may occasion normalization of the superconductor and destabilize the generator output through loss of field excitation. This paper addresses the question of designing the superconducting winding and its cryogenic cooling system for stability in the presence of large disturbances, a capability which has been called high fault tolerance

  9. Fault Tolerance Assistant (FTA): An Exception Handling Programming Model for MPI Applications

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Aiman [Univ. of Chicago, IL (United States). Dept. of Computer Science; Laguna, Ignacio [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Sato, Kento [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Islam, Tanzima [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Mohror, Kathryn [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-05-23

    Future high-performance computing systems may face frequent failures with their rapid increase in scale and complexity. Resilience to faults has become a major challenge for large-scale applications running on supercomputers, which demands fault tolerance support for prevalent MPI applications. Among failure scenarios, process failures are one of the most severe issues as they usually lead to termination of applications. However, the widely used MPI implementations do not provide mechanisms for fault tolerance. We propose FTA-MPI (Fault Tolerance Assistant MPI), a programming model that provides support for failure detection, failure notification and recovery. Specifically, FTA-MPI exploits a try/catch model that enables failure localization and transparent recovery of process failures in MPI applications. We demonstrate FTA-MPI with synthetic applications and a molecular dynamics code CoMD, and show that FTA-MPI provides high programmability for users and enables convenient and flexible recovery of process failures.

  10. A benchmark for fault tolerant flight control evaluation

    Science.gov (United States)

    Smaili, H.; Breeman, J.; Lombaerts, T.; Stroosma, O.

    2013-12-01

    A large transport aircraft simulation benchmark (REconfigurable COntrol for Vehicle Emergency Return - RECOVER) has been developed within the GARTEUR (Group for Aeronautical Research and Technology in Europe) Flight Mechanics Action Group 16 (FM-AG(16)) on Fault Tolerant Control (2004 2008) for the integrated evaluation of fault detection and identification (FDI) and reconfigurable flight control strategies. The benchmark includes a suitable set of assessment criteria and failure cases, based on reconstructed accident scenarios, to assess the potential of new adaptive control strategies to improve aircraft survivability. The application of reconstruction and modeling techniques, based on accident flight data, has resulted in high-fidelity nonlinear aircraft and fault models to evaluate new Fault Tolerant Flight Control (FTFC) concepts and their real-time performance to accommodate in-flight failures.

  11. Fault tolerant strategies for automated operation of nuclear reactors

    International Nuclear Information System (INIS)

    This paper introduces an automatic control system incorporating a number of verification, validation, and command generation tasks with-in a fault-tolerant architecture. The integrated system utilizes recent methods of artificial intelligence such as neural networks and fuzzy logic control. Furthermore, advanced signal processing and nonlinear control methods are also included in the design. The primary goal is to create an on-line capability to validate signals, analyze plant performance, and verify the consistency of commands before control decisions are finalized. The application of this approach to the automated startup of the Experimental Breeder Reactor-II (EBR-II) is performed using a validated nonlinear model. The simulation results show that the advanced concepts have the potential to improve plant availability andsafety

  12. Buffered coscheduling for parallel programming and enhanced fault tolerance

    Science.gov (United States)

    Petrini, Fabrizio; Feng, Wu-chun

    2006-01-31

    A computer implemented method schedules processor jobs on a network of parallel machine processors or distributed system processors. Control information communications generated by each process performed by each processor during a defined time interval is accumulated in buffers, where adjacent time intervals are separated by strobe intervals for a global exchange of control information. A global exchange of the control information communications at the end of each defined time interval is performed during an intervening strobe interval so that each processor is informed by all of the other processors of the number of incoming jobs to be received by each processor in a subsequent time interval. The buffered coscheduling method of this invention also enhances the fault tolerance of a network of parallel machine processors or distributed system processors

  13. Fault tolerance in space-based digital signal processing and switching systems: Protecting up-link processing resources, demultiplexer, demodulator, and decoder

    Science.gov (United States)

    Redinbo, Robert

    1994-01-01

    Fault tolerance features in the first three major subsystems appearing in the next generation of communications satellites are described. These satellites will contain extensive but efficient high-speed processing and switching capabilities to support the low signal strengths associated with very small aperture terminals. The terminals' numerous data channels are combined through frequency division multiplexing (FDM) on the up-links and are protected individually by forward error-correcting (FEC) binary convolutional codes. The front-end processing resources, demultiplexer, demodulators, and FEC decoders extract all data channels which are then switched individually, multiplexed, and remodulated before retransmission to earth terminals through narrow beam spot antennas. Algorithm based fault tolerance (ABFT) techniques, which relate real number parity values with data flows and operations, are used to protect the data processing operations. The additional checking features utilize resources that can be substituted for normal processing elements when resource reconfiguration is required to replace a failed unit.

  14. Secure & Fault Tolerance Handoff in Vanet Using Special Mobile Agent

    OpenAIRE

    Shivani Jain; HimanshuTyagi; Charu Gupta

    2013-01-01

    Vehicular Traffic poses an emerging issue nowadays. The critical factors for the data communication are speed and time tradeoffs. For data communication, gathering and retrieving information many cost-effective and tested techniques are required in VANET. Client server architectures being coercive are commonly used in spite of having drawbacks of fault and time in-effectiveness. This paper elaborates a proposed method in VANET for fault tolerance information retrieval based on ...

  15. Production of Reliable Flight Crucial Software: Validation Methods Research for Fault Tolerant Avionics and Control Systems Sub-Working Group Meeting

    Science.gov (United States)

    Dunham, J. R. (Editor); Knight, J. C. (Editor)

    1982-01-01

    The state of the art in the production of crucial software for flight control applications was addressed. The association between reliability metrics and software is considered. Thirteen software development projects are discussed. A short term need for research in the areas of tool development and software fault tolerance was indicated. For the long term, research in format verification or proof methods was recommended. Formal specification and software reliability modeling, were recommended as topics for both short and long term research.

  16. Fault-tolerant three-level inverter

    Science.gov (United States)

    Edwards, John; Xu, Longya; Bhargava, Brij B.

    2006-12-05

    A method for driving a neutral point clamped three-level inverter is provided. In one exemplary embodiment, DC current is received at a neutral point-clamped three-level inverter. The inverter has a plurality of nodes including first, second and third output nodes. The inverter also has a plurality of switches. Faults are checked for in the inverter and predetermined switches are automatically activated responsive to a detected fault such that three-phase electrical power is provided at the output nodes.

  17. A Novel Nanometric Fault Tolerant Reversible Subtractor Circuit

    Directory of Open Access Journals (Sweden)

    Mozhgan Shiri

    2012-11-01

    Full Text Available Reversibility plays an important role when energy efficient computations are considered. Reversible logic circuits have received significant attention in quantum computing, low power CMOS design, optical information processing and nanotechnology in the recent years. This study proposes a new fault tolerant reversible half-subtractor and a new fault tolerant reversible full-subtractor circuit with nanometric scales. Also in this paper we demonstrate how the well-known and important, PERES gate and TR gate can be synthesized from parity preserving reversible gates. All the designs have nanometric scales.

  18. Study on Software Fault Injection Based on Onboard System

    Institute of Scientific and Technical Information of China (English)

    PENGJunjie; HONGBingrong; YUANChengjun; LIAiguo; WEIZhenhua; QIAOYongqiang

    2005-01-01

    Fault injection techniques are the effective methods to evaluate the dependability and validate the fault tolerance mechanisms of computer systems. Among the different fault injection techniques, software implemented fault injection technique is regarded as one of the most promising technique for evaluation of the dependability of computer systems. In this paper, combined the advantages of software fault injection and the particularity of onboard system, a new software fault injection model, which can be used to evaluate the dependability and validate the fault tolerance mechanisms of the onboard system, is put forward. To evaluate the dependability of on boardsystem effectively, the application algorithm on how to use the model is presented. The experimental results show that using the fault injection model and algorithm put forward in this paper, not only most of low-level faults such as processor register faults, memory faults and so on can be injected, but also some high-level faults such as code faults, branch faults etc. can be injected, which can be used to evaluate the dependability of the onboard systems.

  19. 具有通信约束的网络化控制系统容错控制研究%Fault-Tolerant Control Research for Networked Control System under Communication Constraints

    Institute of Scientific and Technical Information of China (English)

    霍志红; 方华京

    2006-01-01

    Implementing a control system over a communication network induces inevitable time delays that may degrade performance and even cause instability. One of the most effective ways to reduce the negative effect of delays on the performance of networked control system (NCS) is to reduce network traffic. In this paper, adjustable deadbands are explored as a solution to reduce network traffic in NCS. A method of fault-tolerant control of networked control system is presented,which takes into account system response as well as network traffic. The integrity design for a kind of NCS with sensor failures and actuator failures is analyzed based on robust fault-tolerant control theory and information scheduling. After detailed theoretical analysis, the paper also provides the simulation results, which further validate the proposed scheme.

  20. Fault Tolerant, Radiation Hard DSP Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to develop a radiation tolerant/hardened signal processing node, which effectively utilizes state-of-the-art commercial semiconductors plus our...

  1. Energy Bounds for Fault-Tolerant Nanoscale Designs

    CERN Document Server

    Marculescu, Diana

    2011-01-01

    The problem of determining lower bounds for the energy cost of a given nanoscale design is addressed via a complexity theory-based approach. This paper provides a theoretical framework that is able to assess the trade-offs existing in nanoscale designs between the amount of redundancy needed for a given level of resilience to errors and the associated energy cost. Circuit size, logic depth and error resilience are analyzed and brought together in a theoretical framework that can be seamlessly integrated with automated synthesis tools and can guide the design process of nanoscale systems comprised of failure prone devices. The impact of redundancy addition on the switching energy and its relationship with leakage energy is modeled in detail. Results show that 99% error resilience is possible for fault-tolerant designs, but at the expense of at least 40% more energy if individual gates fail independently with probability of 1%.

  2. Open-Switch Fault Diagnosis and Fault Tolerant for Matrix Converter with Finite Control Set-Model Predictive Control

    DEFF Research Database (Denmark)

    Peng, Tao; Dan, Hanbing; Yang, Jian;

    2016-01-01

    topology and a cost function to select the best switching state for the next sampling period. The proposed fault diagnosis method is realized by monitoring the load currents and judging the switching state to locate the faulty switch. Compared to the conventional modulation strategies such as carrier......-switch fault conditions without any redundant hardware, a fault tolerant strategy based on predictive control is also studied. The fault tolerant strategy is to select the most appropriate switching state, associated with the remaining normal switches of the MC. Experiment results are presented to show...... the feasibility and effectiveness of the proposed fault diagnosis method and fault tolerant strategy....

  3. Active fault-tolerant control strategy of large civil aircraft under elevator failures

    Directory of Open Access Journals (Sweden)

    Wang Xingjian

    2015-12-01

    Full Text Available Aircraft longitudinal control is the most important actuation system and its failures would lead to catastrophic accident of aircraft. This paper proposes an active fault-tolerant control (AFTC strategy for civil aircraft with different numbers of faulty elevators. In order to improve the fault-tolerant flight control system performance and effective utilization of the control surface, trimmable horizontal stabilizer (THS is considered to generate the extra pitch moment. A suitable switching mechanism with performance improvement coefficient is proposed to determine when it is worthwhile to utilize THS. Furthermore, AFTC strategy is detailed by using model following technique and the proposed THS switching mechanism. The basic fault-tolerant controller is designed to guarantee longitudinal control system stability and acceptable performance degradation under partial elevators failure. The proposed AFTC is applied to Boeing 747-200 numerical model and simulation results validate the effectiveness of the proposed AFTC approach.

  4. Active fault-tolerant control strategy of large civil aircraft under elevator failures

    Institute of Scientific and Technical Information of China (English)

    Wang Xingjian; Wang Shaoping; Yang Zhongwei; Zhang Chao

    2015-01-01

    Aircraft longitudinal control is the most important actuation system and its failures would lead to catastrophic accident of aircraft. This paper proposes an active fault-tolerant control (AFTC) strategy for civil aircraft with different numbers of faulty elevators. In order to improve the fault-tolerant flight control system performance and effective utilization of the control surface, trim-mable horizontal stabilizer (THS) is considered to generate the extra pitch moment. A suitable switching mechanism with performance improvement coefficient is proposed to determine when it is worthwhile to utilize THS. Furthermore, AFTC strategy is detailed by using model following technique and the proposed THS switching mechanism. The basic fault-tolerant controller is designed to guarantee longitudinal control system stability and acceptable performance degradation under partial elevators failure. The proposed AFTC is applied to Boeing 747-200 numerical model and simulation results validate the effectiveness of the proposed AFTC approach.

  5. FAULT TOLERANCE USING CREDENTIALS MANAGEMENT IN ONLINE TRANSACTION APPLICATION

    Directory of Open Access Journals (Sweden)

    L. Javid Ali

    2014-07-01

    Full Text Available Web applications play a vital role in the IT field for satisfying the web customer. The customer always depends on the online transaction processing system. The web application has various forms which gives a complete service to the customer. These various forms have options that are used to satisfy the customer’s needs because of the attraction over web sites existing in the global market. The traditional web pages will be closed from the current session whenever the customer selects an improper option because of single sign-on property. Selection of wrong option that is not suitable for the current session will lead to reliability problem. If the same user needs the same service, again he has to navigate from home page to the required page, thus adding up extra burden on customer. The customer session should be maintained properly, so that the customer’s satisfaction is retained over the online web application. The existing system classifies the user with their access level and also their fault level. The main objective of the proposed work is to manage the credential in all levels in order to keep the valuable customer for a long time of access in the current session. The credential management and session management are used to manage a multilevel credential from web client to web resource level and vice versa. The options selected by the customer can be classified based on the fault and type of access. The credential management also performs the maintenance process for fixing the fault tolerance level to the web user. A complete log is recorded to trace the overall process in the online transaction processing.

  6. Real-time fault tolerant full adder design for critical applications

    Directory of Open Access Journals (Sweden)

    Pankaj Kumar

    2016-09-01

    Full Text Available In the complex computing system, processing units are dealing with devices of smaller size, which are sensitive to the transient faults. A transient fault occurs in a circuit caused by the electromagnetic noises, cosmic rays, crosstalk and power supply noise. It is very difficult to detect these faults during offline testing. Hence an area efficient fault tolerant full adder for testing and repairing of transient and permanent faults occurred in single and multi-net is proposed. Additionally, the proposed architecture can also detect and repair permanent faults. This design incurs much lower hardware overheads relative to the traditional hardware architecture. In addition to this, proposed design also provides higher error detection and correction efficiency when compared to the existing designs.

  7. A New and Efficient Algorithm-Based Fault Tolerance Scheme for A Million Way Parallelism

    CERN Document Server

    Yao, Erlin; Wang, Rui; Zhang, Wenli; Tan, Guangming

    2011-01-01

    Fault tolerance overhead of high performance computing (HPC) applications is becoming critical to the efficient utilization of HPC systems at large scale. HPC applications typically tolerate fail-stop failures by checkpointing. Another promising method is in the algorithm level, called algorithmic recovery. These two methods can achieve high efficiency when the system scale is not very large, but will both lose their effectiveness when systems approach the scale of Exaflops, where the number of processors including in system is expected to achieve one million. This paper develops a new and efficient algorithm-based fault tolerance scheme for HPC applications. When failure occurs during the execution, we do not stop to wait for the recovery of corrupted data, but replace them with the corresponding redundant data and continue the execution. A background accelerated recovery method is also proposed to rebuild redundancy to tolerate multiple times of failures during the execution. To demonstrate the feasibility ...

  8. Modular Multilevel Converter Control Strategy with Fault Tolerance

    DEFF Research Database (Denmark)

    Teodorescu, Remus; Eni, Emanuel-Petre; Mathe, Laszlo;

    2013-01-01

    The Modular Multilevel Converter (MMC) technology has recently emerged in VSC-HVDC applications where it demonstrated higher efficiency and fault tolerance compared to the classical 2-level topology. Due to the ability of MMC to connect to HV levels, MMC can be also used in transformerless STATCO...

  9. Critique of Fault-Tolerant Quantum Information Processing

    OpenAIRE

    Alicki, Robert

    2013-01-01

    This is a chapter in a book \\emph{Quantum Error Correction} edited by D. A. Lidar and T. A. Brun, and published by Cambridge University Press (2013)\\\\ (http://www.cambridge.org/us/academic/subjects/physics/quantum-physics-quantum-information-and-quantum-computation/quantum-error-correction)\\\\ presenting the author's view on feasibility of fault-tolerant quantum information processing.

  10. Nonlinear and fault-tolerant flight control using multivariate splines

    NARCIS (Netherlands)

    Tol, H.J.; De Visser, C.C.; Van Kampen, E.J.; Chu, Q.P.

    2015-01-01

    This paper presents a study on fault tolerant flight control of a high performance aircraft using multivariate splines. The controller is implemented by making use of spline model based adaptive nonlinear dynamic inversion (NDI). This method, indicated as SANDI, combines NDI control with nonlinear c

  11. A benchmark for fault tolerant flight control evaluation

    NARCIS (Netherlands)

    Smaili, H.; Breeman, J.; Lombaerts, T.; Stroosma, O.

    2013-01-01

    A large transport aircraft simulation benchmark (REconfigurable COntrol for Vehicle Emergency Return − RECOVER) has been developed within the GARTEUR (Group for Aeronautical Research and Technology in Europe) Flight Mechanics Action Group 16 (FM-AG(16)) on Fault Tolerant Control (2004 2008) for the

  12. Fault Tolerant Congestion based Algorithms in OBS Network

    Directory of Open Access Journals (Sweden)

    Hardeep Singh

    2011-12-01

    Full Text Available In Optical Burst Switched networks, each light path carry huge amount of traffic, path failures may damage the user application. Hence fault-tolerance becomes an important issue on these networks. Blocking probability is a key index of quality of service in Optical Burst Switched (OBS network. The Erlang formula has been used extensively in the traffic engineering of optical communication to calculate the blocking probability. The paper revisits burst contention resolution problems in OBS networks. When the network is overloaded, no contention resolution scheme would effectively avoid the collision and cause blocking. It is important to first decide, a good routing algorithm and then to choose a wavelength assignment scheme. In this paper we have developed two algorithms, Fault Tolerant Optimized Blocking Algorithm (FTOBA and Fault Tolerant Least Congestion Algorithm (FTLCA and then compare the performance of these algorithms on the basis of blocking probability. These algorithms are based upon the congestion on path in OBS network and based on the simulation results, we shows that the reliable and fault tolerant routing algorithms reduces the blocking probability.

  13. Reversible Logic Synthesis of Fault Tolerant Carry Skip BCD Adder

    CERN Document Server

    Islam, Md Saiful; 10.3329/jbas.v32i2.2431

    2010-01-01

    Reversible logic is emerging as an important research area having its application in diverse fields such as low power CMOS design, digital signal processing, cryptography, quantum computing and optical information processing. This paper presents a new 4*4 parity preserving reversible logic gate, IG. The proposed parity preserving reversible gate can be used to synthesize any arbitrary Boolean function. It allows any fault that affects no more than a single signal readily detectable at the circuit's primary outputs. It is shown that a fault tolerant reversible full adder circuit can be realized using only two IGs. The proposed fault tolerant full adder (FTFA) is used to design other arithmetic logic circuits for which it is used as the fundamental building block. It has also been demonstrated that the proposed design offers less hardware complexity and is efficient in terms of gate count, garbage outputs and constant inputs than the existing counterparts.

  14. Final Project Report. Scalable fault tolerance runtime technology for petascale computers

    Energy Technology Data Exchange (ETDEWEB)

    Krishnamoorthy, Sriram [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Sadayappan, P [Ohio State Univ., Columbus, OH (United States)

    2015-06-16

    With the massive number of components comprising the forthcoming petascale computer systems, hardware failures will be routinely encountered during execution of large-scale applications. Due to the multidisciplinary, multiresolution, and multiscale nature of scientific problems that drive the demand for high end systems, applications place increasingly differing demands on the system resources: disk, network, memory, and CPU. In addition to MPI, future applications are expected to use advanced programming models such as those developed under the DARPA HPCS program as well as existing global address space programming models such as Global Arrays, UPC, and Co-Array Fortran. While there has been a considerable amount of work in fault tolerant MPI with a number of strategies and extensions for fault tolerance proposed, virtually none of advanced models proposed for emerging petascale systems is currently fault aware. To achieve fault tolerance, development of underlying runtime and OS technologies able to scale to petascale level is needed. This project has evaluated range of runtime techniques for fault tolerance for advanced programming models.

  15. Empirical Study of FFANN Tolerance to Weight Stuck at Max/Min Fault

    Directory of Open Access Journals (Sweden)

    Amit Prakash Singh

    2010-04-01

    Full Text Available Fault tolerance property of artificial neural networks has been investigated with reference to the hardware model of artificial neural networks. Weight fault is an important link, which causes breakup between two nodes. In this paper three types of weight faults have been explained. Experiments have been performed to demonstrate fault tolerance behavior of feedforward artificial neural network for weight-stuck-MAX/MIN fault. Effect of weight-stuckMAX/MIN fault on trained network has been analyzed in this paper. The obtained results suggest that networks are not fault tolerant to this type of fault.

  16. Fault-tolerant Algorithms for Tick-Generation in Asynchronous Logic: Robust Pulse Generation

    CERN Document Server

    Dolev, Danny; Lenzen, Christoph; Schmid, Ulrich

    2011-01-01

    Today's hardware technology presents a new challenge in designing robust systems. Deep submicron VLSI technology introduced transient and permanent faults that were never considered in low-level system designs in the past. Still, robustness of that part of the system is crucial and needs to be guaranteed for any successful product. Distributed systems, on the other hand, have been dealing with similar issues for decades. However, neither the basic abstractions nor the complexity of contemporary fault-tolerant distributed algorithms match the peculiarities of hardware implementations. This paper is intended to be part of an attempt striving to overcome this gap between theory and practice for the clock synchronization problem. Solving this task sufficiently well will allow to build a very robust high-precision clocking system for hardware designs like systems-on-chips in critical applications. As our first building block, we describe and prove correct a novel Byzantine fault-tolerant self-stabilizing pulse syn...

  17. Combining dynamical decoupling with fault-tolerant quantum computation

    CERN Document Server

    Ng, Hui Khoon; Preskill, John

    2009-01-01

    We study how dynamical decoupling (DD) pulse sequences can improve the reliability of quantum computers. We prove upper bounds on the accuracy of DD-protected quantum gates and derive sufficient conditions for DD-protected gates to outperform unprotected gates. Under suitable conditions, fault-tolerant quantum circuits constructed from DD-protected gates can tolerate stronger noise, and have a lower overhead cost, than fault-tolerant circuits constructed from unprotected gates. Our accuracy estimates depend on the dynamics of the bath that couples to the quantum computer, and can be expressed either in terms of the operator norm of the bath's Hamiltonian or in terms of the power spectrum of bath correlations; we explain in particular how the performance of recursively generated concatenated pulse sequences can be analyzed from either viewpoint. Our results apply to Hamiltonian noise models with limited spatial correlations.

  18. Active Fault Isolation in MIMO Systems

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik; Poulsen, Niels Kjølstad

    2014-01-01

    isolation is based directly on the input/output s ignals applied for the fault detection. It is guaranteed that the fault group includes the fault that had occurred in the system. The second step is individual fault isolation in the fault group . Both types of isolation are obtained by applying dedicated......Active fault isolation of parametric faults in closed-loop MIMO system s are considered in this paper. The fault isolation consists of two steps. T he first step is group- wise fault isolation. Here, a group of faults is isolated from other pos sible faults in the system. The group-wise fault...

  19. Fuzzy fault diagnostic system based on fault tree analysis

    OpenAIRE

    Yang, Zong Xiao; Suzuki, Kazuhiko; Shimada, Yukiyasu; Sayama, Hayatoshi

    1995-01-01

    A method is presented for process fault diagnosis using information from fault tree analysis and uncertainty/imprecision of data. Fault tree analysis, which has been used as a method of system reliability/safety analysis, provides a procedure for identifying failures within a process. A fuzzy fault diagnostic system is constructed which uses the fuzzy fault tree analysis to represent a knowledge of the causal relationships in process operation and control system. The proposed method is applie...

  20. Passive fault tolerant control of a double inverted pendulum - a case study

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik; Stoustrup, Jakob

    2005-01-01

    A passive fault tolerant control scheme is suggested, in which a nominal controller is augmented with an additional block, which guarantees stability and performance after the occurrence of a fault. The method is based on the YJBK parameterization, which requires the nominal controller to be impl...... to be implemented in observer based form. The proposed method is applied to a double inverted pendulum system, for which an H_inf controller has been designed and verified in a lab setup. In this case study, the fault is a degradation of the tacho loop....

  1. Design of intelligent fault-tolerant to passive underwater integrated navigation system%水下无源组合导航系统智能容错方法设计

    Institute of Scientific and Technical Information of China (English)

    李佩娟; 徐晓苏; 王立辉; 李瑶

    2013-01-01

      为提高自主水下航行器的导航精度,比较目前 AUV 常用的水下导航方式,将捷联式惯性导航系统与地球物理导航系统相结合构成水下无源组合导航系统。采用容错联邦卡尔曼滤波对各子系统信息进行故障诊断、系统重构和融合。针对传统的2c检验法不能确定故障具体原因,而仅能判断量测信息是否有效的缺陷,提出利用神经网络辅助2c检验法进行故障诊断。通过对水下组合导航系统算法进行仿真分析,结果表明该算法能够快速、准确地判断系统故障源,通过故障隔离和系统重构,使系统在故障情况下依然保持正常工作。%To improve the navigation accuracy of autonomous underwater vehicle, an integrated navigation system was proposed, which was composed of strapdown inertial navigation system (SINS), terrain-aided navigation (TAN) system and gravity-aided navigation (GAN) system. A fault-tolerant federated Kalman filter was used to fuse the various navigation sensors, detect the system fault and reconstruct the navigation system. In view that traditional cai-square hypothesis testing processes fault detection cannot determine the specific cause of the fault, and could only determine the validity of measure information, a new fault detection algorithm based on neural network was adopted. The application on underwater integrated navigation system demonstrates that the algorithm can rapidly and accurately detecting and identify the faults in the system. Therefore the effective fault isolating can be performed to realize the fault tolerance navigation.

  2. Short Survey on Design for Fault Tolerance of Computer Systems%计算机系统容错设计简述

    Institute of Scientific and Technical Information of China (English)

    鄢贵海; 李晓维

    2013-01-01

    Highly reliable computer systems are the foundation of QoS (Quality of Services) of IT services. Since the birth of ENIAC, the ifrst electronic computer in history, reliability has become one of the major challenges in computer design. Fault tolerance serves as a major approach to high reliability. It is also a systematic science crossing multiple logical layers of the classical computing stacks. The design opportunity comes from the bottom device layer to the much higher application layer. Each logical layer faces speciifc design challenges. Following a bottom-up style, we brielfy survey these classical approaches in design for reliability.%高可靠计算机系统是是保证信息服务质量的基石。从第一台计算机ENIAC诞生起,可靠性就是计算机系统面临的主要挑战之一,容错设计是实现可靠性的有效途径,也是一项典型的跨计算机多个设计层次的系统科学。从底层的器件到顶层的应用程序,都存在优化可靠性的设计空间,每个层次的设计面向特定的可靠性设计挑战。文章将遵循自底向上的逻辑层次简述这些经典的设计方法。

  3. Fault-Tolerant Software-Defined Radio on Manycore

    Science.gov (United States)

    Ricketts, Scott

    2015-01-01

    Software-defined radio (SDR) platforms generally rely on field-programmable gate arrays (FPGAs) and digital signal processors (DSPs), but such architectures require significant software development. In addition, application demands for radiation mitigation and fault tolerance exacerbate programming challenges. MaXentric Technologies, LLC, has developed a manycore-based SDR technology that provides 100 times the throughput of conventional radiationhardened general purpose processors. Manycore systems (30-100 cores and beyond) have the potential to provide high processing performance at error rates that are equivalent to current space-deployed uniprocessor systems. MaXentric's innovation is a highly flexible radio, providing over-the-air reconfiguration; adaptability; and uninterrupted, real-time, multimode operation. The technology is also compliant with NASA's Space Telecommunications Radio System (STRS) architecture. In addition to its many uses within NASA communications, the SDR can also serve as a highly programmable research-stage prototyping device for new waveforms and other communications technologies. It can also support noncommunication codes on its multicore processor, collocated with the communications workload-reducing the size, weight, and power of the overall system by aggregating processing jobs to a single board computer.

  4. A fault-tolerant voltage measurement method for series connected battery packs

    Science.gov (United States)

    Xia, Bing; Mi, Chris

    2016-03-01

    This paper proposes a fault-tolerant voltage measurement method for battery management systems. Instead of measuring the voltage of individual cells, the proposed method measures the voltage sum of multiple battery cells without additional voltage sensors. A matrix interpretation is developed to demonstrate the viability of the proposed sensor topology to distinguish between sensor faults and cell faults. A methodology is introduced to isolate sensor and cell faults by locating abnormal signals. A measurement electronic circuit is proposed to implement the design concept. Simulation and experiment results support the mathematical analysis and validate the feasibility and robustness of the proposed method. In addition, the measurement problem is generalized and the condition for valid sensor topology is discovered. The tuning of design parameters are analyzed based on fault detection reliability and noise levels.

  5. Observer-based Fault Detection and Isolation for Nonlinear Systems

    DEFF Research Database (Denmark)

    Lootsma, T.F.

    With the rise in automation the increase in fault detectionand isolation & reconfiguration is inevitable. Interest in fault detection and isolation (FDI) for nonlinear systems has grown significantly in recent years. The design of FDI is motivated by the need for knowledge about occurring faults......-tolerance can be applied to ordinary industrial processes that are not categorized as high risk applications, but where high availability is desirable. The quality of fault-tolerant control is totally dependent on the quality of the underlying algorithms. They detect possible faults, and later reconfigure...... control software to handle the effects of the particular fault event. In the past mainly linear FDI methods were developed, but as most industrial plants show nonlinear behavior, nonlinear methods for fault diagnosis could probably perform better. This thesis considers the design of FDI for nonlinear...

  6. Fault Tolerant Control Using Proportional-Integral-Derivative Controller Tuned by Genetic Algorithm

    Directory of Open Access Journals (Sweden)

    S. Kanthalakshmi

    2011-01-01

    Full Text Available Problem statement: The growing demand for reliability, maintainability and survivability in industrial processes has drawn significant research in fault detection and fault tolerant control domain. A fault is usually defined as an unexpected change in a system, such as component malfunction and variations in operating condition, which tends to degrade the overall system performance. The purpose of fault detection is to detect these malfunctions to take proper action in order to prevent faults from developing into a total system failure. Approach: In this study an effective integrated fault detection and fault tolerant control scheme was developed for a class of LTI system. The scheme was based on a Kalman filter for simultaneous state and fault parameter estimation, statistical decisions for fault detection and activation of controller reconfiguration. Proportional-Integral-Derivative (PID control schemes continue to provide the simplest and yet effective solutions to most of the control engineering applications today. Determination or tuning of the PID parameters continues to be important as these parameters have a great influence on the stability and performance of the control system. In this study GA was proposed to tune the PID controller. Results: The results reflect that proposed scheme improves the performance of the process in terms of time domain specifications, robustness to parametric changes and optimum stability. Also, A comparison with the conventional Ziegler-Nichols method proves the superiority of GA based system. Conclusion: This study demonstrates the effectiveness of genetic algorithm in tuning of a PID controller with optimum parameters. It is, moreover, proved to be robust to the variations in plant dynamic characteristics and disturbances assuring a parameter-insensitive operation of the process.

  7. High Performance Modeling of Intelligent Pattern Recognition with Enhanced Fault-Tolerance in Real Time

    Directory of Open Access Journals (Sweden)

    Renukaradhya P.C

    2014-03-01

    Full Text Available Designing an ANN which could recognize the learned patterns even if there is variation in applied test patterns from learned patterns. A mechanism has been developed which provided the recognition facility intelligently. Recognition of patterns can be broadly categorized into two classes. When precision of recognition is not defined, term name “Forced recognition” given to the process. When precision of recognition is properly defined termed “Custom recognition” given to process. Analysis of fault tolerant property of feed forward architecture will be given training with back propagation method. Under this, analysis of effect of initially selected random weights and what should be the nature of random weights so that to maximize the fault tolerance capability of system has done. Analysis can be done with two different distribution namely Gaussian distribution and Uniform distribution. Effect of faults at output is also a function of fault position in ANN system like Hidden layer weight, Output layer weights, with processing elements at hidden layer. Analysis capability of back propagation algorithm itself is to tolerate the fault by learning process. A development of test mechanism to check faulty system in coming future is ANN system in hardware world i.e. on the VLSI chip. Once the architecture implemented it is required a mechanism to check the functioning. Analysis of internal parameters of ANN is completely research work with behavior of internal parameters, which will provide all responsible factors behind success of an ANN.

  8. Lightweight storage and overlay networks for fault tolerance.

    Energy Technology Data Exchange (ETDEWEB)

    Oldfield, Ron A.

    2010-01-01

    The next generation of capability-class, massively parallel processing (MPP) systems is expected to have hundreds of thousands to millions of processors, In such environments, it is critical to have fault-tolerance mechanisms, including checkpoint/restart, that scale with the size of applications and the percentage of the system on which the applications execute. For application-driven, periodic checkpoint operations, the state-of-the-art does not provide a scalable solution. For example, on today's massive-scale systems that execute applications which consume most of the memory of the employed compute nodes, checkpoint operations generate I/O that consumes nearly 80% of the total I/O usage. Motivated by this observation, this project aims to improve I/O performance for application-directed checkpoints through the use of lightweight storage architectures and overlay networks. Lightweight storage provide direct access to underlying storage devices. Overlay networks provide caching and processing capabilities in the compute-node fabric. The combination has potential to signifcantly reduce I/O overhead for large-scale applications. This report describes our combined efforts to model and understand overheads for application-directed checkpoints, as well as implementation and performance analysis of a checkpoint service that uses available compute nodes as a network cache for checkpoint operations.

  9. Fault Tolerance for Industrial Actuators in Absence of Accurate Models and Hardware Redundancy

    DEFF Research Database (Denmark)

    Papageorgiou, Dimitrios; Blanke, Mogens; Niemann, Hans Henrik;

    2015-01-01

    This paper investigates Fault-Tolerant Control for closed-loop systems where only coarse models are available and there is lack of actuator and sensor redundancies. The problem is approached in the form of a typical servomotor in closed-loop. A linear model is extracted from input/output data to ...

  10. Fault Tolerant Characteristics of Artificial Neural Network Electronic Hardware

    Science.gov (United States)

    Zee, Frank

    1995-01-01

    The fault tolerant characteristics of analog-VLSI artificial neural network (with 32 neurons and 532 synapses) chips are studied by exposing them to high energy electrons, high energy protons, and gamma ionizing radiations under biased and unbiased conditions. The biased chips became nonfunctional after receiving a cumulative dose of less than 20 krads, while the unbiased chips only started to show degradation with a cumulative dose of over 100 krads. As the total radiation dose increased, all the components demonstrated graceful degradation. The analog sigmoidal function of the neuron became steeper (increase in gain), current leakage from the synapses progressively shifted the sigmoidal curve, and the digital memory of the synapses and the memory addressing circuits began to gradually fail. From these radiation experiments, we can learn how to modify certain designs of the neural network electronic hardware without using radiation-hardening techniques to increase its reliability and fault tolerance.

  11. BFTDT: Byzantine Fault Tolerance tryout for Dependable Transactions in Cloud

    Directory of Open Access Journals (Sweden)

    Gayathri S

    2012-11-01

    Full Text Available Cloud Web Services (CWS is the technology used for business collaboration and integration among the web users. The Web Services Atomic Transactions (WS-AT have been used for the trusted distributed transaction processing over the web. The WS-AT in the distributed sense has byzantine faults to overcome that Byzantine Faults Techniques (BFT is used. The reliable coordinator provides the services that are Coordination services, Activation services, Registration Services and Completion services which make the transaction effective and reliable. In the trusted environment, to evade congestion of the resources, fair share bandwidth allocation scheme is used to allocate separate bandwidth for each web users and the transaction is processed Coordinator server and the Transaction Processing Monitor (TPM. The WS-AT for business applications analysis shows the high degree of dependability, security, trust, fault tolerance and fairness of the resources in the trusted environment.

  12. TRSTR: A Fault- Tolerant Microprocessor Architecture Based on SMT

    Institute of Scientific and Technical Information of China (English)

    YANG Hua; CUI Gang; YANG Xiao-zong

    2005-01-01

    Based on Simultaneous Multithreading (SMT),we propose a fault-tolerant scheme called Tri-modular Redundantly and Simultaneously Threaded processor with Recovery (TRSTR). TRSTR features as following: First, we introduce an arbitrator context into the conventional SRT (Simultaneous and Redundantly Threaded), which acts as an arbitrator when results from the other two contexts disagree, or acts as an ordinary thread generally, thus making full use of SMT' s parallelism. Second, we append reconfigurable feature to sphere of replication in SRT, making it more flexible for changing demands and situations. Third, TRSTR has two working modes: Tri-Simultaneous with Voting (TSV) and Dual-Simultaneous with Arbitrator (DSA), which can switch at will. Finally, in addition to transient-fault coverage,TRSTR has on-line self-checking and self-recovering abilities,so as to shield off some permanent faults and reconfigure itself without stopping the crucial job, improving its reliability and availability.

  13. Fault-Tolerant Visual Secret Sharing Schemes without Pixel Expansion

    OpenAIRE

    Justie Su-Tzu Juan; Yung-Chang Chen; Song Guo

    2016-01-01

    Visual cryptography encrypts a secret image into two meaningless random images, called shares, such that it can be decrypted by human vision without any calculations. However, there would be problems in alignment when these two shares are staked by hand in practice. Therefore, this paper presents the fault-tolerant schemes of stacking two shares that are acquired from secret image encryption without pixel expansion. The main idea of these schemes is to combine several pixels as a unit and the...

  14. FAULT TOLERANT SCHEDULING STRATEGY FOR COMPUTATIONAL GRID ENVIRONMENT

    Directory of Open Access Journals (Sweden)

    MALARVIZHI NANDAGOPAL,

    2010-09-01

    Full Text Available Computational grids have the potential for solving large-scale scientific applications using heterogeneous and geographically distributed resources. In addition to the challenges of managing and scheduling these applications, reliability challenges arise because of the unreliable nature of grid infrastructure. Two major problems that are critical to the effective utilization of computational resources are efficient scheduling of jobs and providing fault tolerance in a reliable manner. This paper addresses these problems by combining the checkpoint replication based fault tolerance echanism with Minimum Total Time to Release (MTTR job scheduling algorithm. TTR includes the service time of the job, waiting time in the queue, transfer of input and output data to and from the resource. The MTTR algorithm minimizes the TTR by selecting a computational resource based on job requirements, job characteristics and hardware features of the resources. The fault tolerance mechanism used here sets the job checkpoints based on the resource failure rate. If resource failure occurs, the job is restarted from its last successful state using a checkpoint file from another grid resource. Acritical aspect for an automatic recovery is the availability of checkpoint files. A strategy to increase the availability of checkpoints is replication. Replica Resource Selection Algorithm (RRSA is proposed to provide Checkpoint Replication Service (CRS. Globus Tool Kit is used as the grid middleware to set up a grid environment and evaluate the performance of the proposed approach. The monitoring tools Ganglia and NWS (Network Weather Service are used to gather hardware and network details respectively. The experimental results demonstrate that, the proposed approach effectively schedule the grid jobs with fault tolerant way thereby reduces TTR of the jobs submitted in the grid. Also, it increases the percentage of jobs completed within specified deadline and making the grid

  15. Faster Quantum Chemistry Simulation on Fault-Tolerant Quantum Computers

    OpenAIRE

    Jones, N. Cody; Whitfield, James D.; McMahon, Peter L.; Yung, Man-Hong; Van Meter, Rodney; Aspuru-Guzik, Alan; Yamamoto, Yoshihisa

    2012-01-01

    Quantum computers can in principle simulate quantum physics exponentially faster than their classical counterparts, but some technical hurdles remain. We propose methods which substantially improve the performance of a particular form of simulation, ab initio quantum chemistry, on fault-tolerant quantum computers; these methods generalize readily to other quantum simulation problems. Quantum teleportation plays a key role in these improvements and is used extensively as a computing resource...

  16. Formal verification of fault-tolerant software design: the CSP approach

    OpenAIRE

    Yeung, WL; Schneider, SA

    2005-01-01

    Software design techniques for tolerating both hardware and software faults have been developed over the past few decades. Paradoxically, it is essential that fault-tolerant software is designed with the highest possible rigour to prevent faults in itself. Such rigour is provided by formal methods and aided by model checking. We illustrate an approach to fault-tolerant software design based on communicating sequential processes through a running example.

  17. Fault Diagnosis and Accommodation of LTI systems by modified Youla parameterization

    Directory of Open Access Journals (Sweden)

    Minupriya A

    2012-06-01

    Full Text Available In this paper an Active Fault Tolerant Control (FTC scheme is proposed for Linear Time Invariant (LTI systems, which achieves fault diagnosis followed by fault accommodation. The fault diagnosis scheme is carried out in two steps; Fault detection followed by Fault isolation. Fault detection filter use the sensor measurements to generate residuals, which have a unique static pattern in response to each fault. Distortion in these static patterns generates the probability of the presence of fault. The fault accommodation scheme is carried out using the Generalized Internal Model Control (GIMC architecture, also known as modified Youla parameterization. In addition, performance indices are also evaluated to indicate that the resulting fault tolerant scheme can detect, identify and accommodate actuator and sensor faults under additive faults. The DC motor example is considered for the demonstration of the proposed scheme.

  18. Unconstrained and Constrained Fault-Tolerant Resource Allocation

    CERN Document Server

    Liao, Kewen

    2011-01-01

    First, we study the Unconstrained Fault-Tolerant Resource Allocation (UFTRA) problem (a.k.a. FTFA problem in \\cite{shihongftfa}). In the problem, we are given a set of sites equipped with an unconstrained number of facilities as resources, and a set of clients with set $\\mathcal{R}$ as corresponding connection requirements, where every facility belonging to the same site has an identical opening (operating) cost and every client-facility pair has a connection cost. The objective is to allocate facilities from sites to satisfy $\\mathcal{R}$ at a minimum total cost. Next, we introduce the Constrained Fault-Tolerant Resource Allocation (CFTRA) problem. It differs from UFTRA in that the number of resources available at each site $i$ is limited by $R_{i}$. Both problems are practical extensions of the classical Fault-Tolerant Facility Location (FTFL) problem \\cite{Jain00FTFL}. For instance, their solutions provide optimal resource allocation (w.r.t. enterprises) and leasing (w.r.t. clients) strategies for the cont...

  19. Faster quantum chemistry simulation on fault-tolerant quantum computers

    Science.gov (United States)

    Cody Jones, N.; Whitfield, James D.; McMahon, Peter L.; Yung, Man-Hong; Van Meter, Rodney; Aspuru-Guzik, Alán; Yamamoto, Yoshihisa

    2012-11-01

    Quantum computers can in principle simulate quantum physics exponentially faster than their classical counterparts, but some technical hurdles remain. We propose methods which substantially improve the performance of a particular form of simulation, ab initio quantum chemistry, on fault-tolerant quantum computers; these methods generalize readily to other quantum simulation problems. Quantum teleportation plays a key role in these improvements and is used extensively as a computing resource. To improve execution time, we examine techniques for constructing arbitrary gates which perform substantially faster than circuits based on the conventional Solovay-Kitaev algorithm (Dawson and Nielsen 2006 Quantum Inform. Comput. 6 81). For a given approximation error ɛ, arbitrary single-qubit gates can be produced fault-tolerantly and using a restricted set of gates in time which is O(log ɛ) or O(log log ɛ) with sufficient parallel preparation of ancillas, constant average depth is possible using a method we call programmable ancilla rotations. Moreover, we construct and analyze efficient implementations of first- and second-quantized simulation algorithms using the fault-tolerant arbitrary gates and other techniques, such as implementing various subroutines in constant time. A specific example we analyze is the ground-state energy calculation for lithium hydride.

  20. Adaptive Fault-Tolerant Routing in 2D Mesh with Cracky Rectangular Model

    Directory of Open Access Journals (Sweden)

    Yi Yang

    2014-01-01

    Full Text Available This paper mainly focuses on routing in two-dimensional mesh networks. We propose a novel faulty block model, which is cracky rectangular block, for fault-tolerant adaptive routing. All the faulty nodes and faulty links are surrounded in this type of block, which is a convex structure, in order to avoid routing livelock. Additionally, the model constructs the interior spanning forest for each block in order to keep in touch with the nodes inside of each block. The procedure for block construction is dynamically and totally distributed. The construction algorithm is simple and ease of implementation. And this is a fully adaptive block which will dynamically adjust its scale in accordance with the situation of networks, either the fault emergence or the fault recovery, without shutdown of the system. Based on this model, we also develop a distributed fault-tolerant routing algorithm. Then we give the formal proof for this algorithm to guarantee that messages will always reach their destinations if and only if the destination nodes keep connecting with these mesh networks. So the new model and routing algorithm maximize the availability of the nodes in networks. This is a noticeable overall improvement of fault tolerability of the system.

  1. Algorithm-Based Fault Tolerance for Numerical Subroutines

    Science.gov (United States)

    Tumon, Michael; Granat, Robert; Lou, John

    2007-01-01

    A software library implements a new methodology of detecting faults in numerical subroutines, thus enabling application programs that contain the subroutines to recover transparently from single-event upsets. The software library in question is fault-detecting middleware that is wrapped around the numericalsubroutines. Conventional serial versions (based on LAPACK and FFTW) and a parallel version (based on ScaLAPACK) exist. The source code of the application program that contains the numerical subroutines is not modified, and the middleware is transparent to the user. The methodology used is a type of algorithm- based fault tolerance (ABFT). In ABFT, a checksum is computed before a computation and compared with the checksum of the computational result; an error is declared if the difference between the checksums exceeds some threshold. Novel normalization methods are used in the checksum comparison to ensure correct fault detections independent of algorithm inputs. In tests of this software reported in the peer-reviewed literature, this library was shown to enable detection of 99.9 percent of significant faults while generating no false alarms.

  2. Fault Tolerant Techniques for Spacecraft Data Recorders

    OpenAIRE

    Anderson, Scott

    1990-01-01

    This paper presents the techniques for improving system reliability which SEAKR Engineering employs in the design of their spacecraft solid state data recorders. Briefly, these techniques include Hamming code error correction, periodic memory scrubbing, latch-up protection, excessive capacity, redundant power supplies/control/bus circuits, microcode protection, and shielding.

  3. Effect analysis of faults in digital I and C systems of nuclear power plants

    International Nuclear Information System (INIS)

    A reliability analysis of digital instrumentation and control (I and C) systems in nuclear power plants has been introduced as one of the important elements of a probabilistic safety assessment because of the unique characteristics of digital I and C systems. Digital I and C systems have various features distinguishable from those of analog I and C systems such as software and fault-tolerant techniques. In this work, the faults in a digital I and C system were analyzed and a model for representing the effects of the faults was developed. First, the effects of the faults in a system were analyzed using fault injection experiments. A software-implemented fault injection technique in which faults can be injected into the memory was used based on the assumption that all faults in a system are reflected in the faults in the memory. In the experiments, the effect of a fault on the system output was observed. In addition, the success or failure in detecting the fault by fault-tolerant functions included in the system was identified. Second, a fault tree model for representing that a fault is propagated to the system output was developed. With the model, it can be identified how a fault is propagated to the output or why a fault is not detected by fault-tolerant techniques. Based on the analysis results of the proposed method, it is possible to not only evaluate the system reliability but also identify weak points of fault-tolerant techniques by identifying undetected faults. The results can be reflected in the designs to improve the capability of fault-tolerant techniques. (author)

  4. Optimal Configuration of Fault-Tolerance Parameters for Distributed Server Access

    DEFF Research Database (Denmark)

    Daidone, Alessandro; Renier, Thibault; Bondavalli, Andrea;

    2013-01-01

    Server replication is a common fault-tolerance strategy to improve transaction dependability for services in communications networks. In distributed architectures, fault-diagnosis and recovery are implemented via the interaction of the server replicas with the clients and other entities...... model using stochastic activity networks (SAN) for the evaluation of performance and dependability metrics of a generic transaction-based service implemented on a distributed replication architecture. The composite SAN model can be easily adapted to a wide range of client-server applications deployed...... in replicated server architectures. In order to obtain insight into the system behaviour, a set of relevant environment parameters and controllable fault-tolerance parameters are chosen and the dependability/performance trade-off is evaluated....

  5. Experimental Robot Position Sensor Fault Tolerance Using Accelerometers and Joint Torque Sensors

    Science.gov (United States)

    Aldridge, Hal A.; Juang, Jer-Nan

    1997-01-01

    Robot systems in critical applications, such as those in space and nuclear environments, must be able to operate during component failure to complete important tasks. One failure mode that has received little attention is the failure of joint position sensors. Current fault tolerant designs require the addition of directly redundant position sensors which can affect joint design. The proposed method uses joint torque sensors found in most existing advanced robot designs along with easily locatable, lightweight accelerometers to provide a joint position sensor fault recovery mode. This mode uses the torque sensors along with a virtual passive control law for stability and accelerometers for joint position information. Two methods for conversion from Cartesian acceleration to joint position based on robot kinematics, not integration, are presented. The fault tolerant control method was tested on several joints of a laboratory robot. The controllers performed well with noisy, biased data and a model with uncertain parameters.

  6. Implementation of fault tolerant control for modular multilevel converter using EtherCAT communication

    DEFF Research Database (Denmark)

    Burlacu, Paul Dan; Mathe, Laszlo; Rejas, Marcos;

    2015-01-01

    Modular Multilevel Converter (MMC) is very promising technology this days. It offers fault tolerant capabilities and ensures high efficiency with low output voltage harmonic content which results in need for smaller filter size. A disadvantage of the system is that the control becomes more...... cumbersome due to the high number of the employed submodules. A very efficient way to control the MMC is by using a real time communication platform between the sub-modules and a central unit. Thus, the central unit can deal with the overall control and some of the tasks can be distributed to the submodules....... This communication platform has to ensure a perfect synchronization between the modules, and it should be also fault tolerant. The analysis of a MMC based on EtherCAT is presented in this paper from implementation and module fault point of view. The experimental tests show that the MMC operates after communication...

  7. Fault-tolerance techniques for high-speed fiber-optic networks

    Science.gov (United States)

    Deruiter, John

    1991-01-01

    Four fiber optic network topologies (linear bus, ring, central star, and distributed star) are discussed relative to their application to high data throughput, fault tolerant networks. The topologies are also examined in terms of redundancy and the need to provide for single point, failure free (or better) system operation. Linear bus topology, although traditionally the method of choice for wire systems, presents implementation problems when larger fiber optic systems are considered. Ring topology works well for high speed systems when coupled with a token passing protocol, but it requires a significant increase in protocol complexity to manage system reconfiguration due to ring and node failures. Star topologies offer a natural fault tolerance, without added protocol complexity, while still providing high data throughput capability.

  8. Structural Fault Tolerance of Scale-Free Networks

    Institute of Scientific and Technical Information of China (English)

    HAO Jingbo; YIN Jianping; ZHANG Boyun

    2007-01-01

    The fault tolerance of scale-free networks is examined in this paper. Through the simulation on the changes of the average path length and network fragmentation of the Barabasi-Albert model when faults happen, it can be observed that generic scale-free networks are quite robust to random failures, but are very vulnerable to targeted attacks at the same time. Therefore, an existing optimization strategy for the robustness of scale-free networks to failures and attacks is also introduced. The simulation similar with the above proved that the so-called (1, 0) network has potentially interconnectedness closer to that of a scale-free network and robustness to targeted attacks closer to that of an exponential network. Furthermore, its resistance to random failures is better than that of either of them.

  9. Fault-Tolerant Tree-Based Multicasting in Mesh Multicomputers

    Institute of Scientific and Technical Information of China (English)

    WU Jie; CHEN Xiao

    2001-01-01

    We propose a fault-tolerant tree-based multicast algorithm for 2-dimensional (2-D) meshes based on the concept of the extended safety level which is a vector associated with each node to capture fault information in the neighborhood. In this approach each destination is reached through a minimum number of hops. In order to minimize the total number of traffic steps, three heuristic strategies are proposed. This approach can be easily implemented by pipelined circuit switching (PCS). A simulation study is conducted to measure the total number of traffic steps under different strategies. Our approach is the first attempt to address the faulttolerant tree-based multicast problem in 2-D meshes based on limited global information with a simple model and succinct information.

  10. Robust and Fault Tolerant Control of CD-players

    DEFF Research Database (Denmark)

    Vidal, Enrique Sanchez

    non-ideal discs in non-ideal circumstances) which is the main topic this Ph.D. thesis is focused on. There are three important contributions to the technical field of study treated in the thesis. It is known that the specific characteristics of the CD-drives vary from unit to unit. Traditionally...... and reliable way. The second main contribution is related to robust control. Usually, the nominal and uncertainty models are assumed to be known and the designer is limited to specify the performance requirements. In a more realistic situation, the designer may only have a set of complex points in the Nyquist...... is to be found in the fault-diagnosis and fault-tolerant control fields. One of the main challenges in the positioning control of the focus point in CD-players is to handle two types of disturbances with conflicting requirements in an effective way. While a high bandwidth is desired to better suppress shocks...

  11. Fault tolerant control of electric pitch control system based on single current detection%基于单电流检测的电动变桨系统容错控制

    Institute of Scientific and Technical Information of China (English)

    李宏伟; 付勃; 董海鹰; 杨立霞; 王睿敏

    2016-01-01

    针对电动变桨系统中常见的电流传感器故障,提出一种基于单电流检测的电动变桨系统变论域模糊容错控制方法。当变桨系统发生单个或两个电流传感器故障时,该方法利用直流母线电流传感器对所缺失的电流信息进行重构,保证三相电流能在任意两个相邻采样周期内得到及时更新,确保闭环系统稳定,并通过自适应阈值故障判断法完成故障相电流传感器的切换及容错。针对调制法引起的重构信号误差及电动变桨系统的主要控制目标,将变论域模糊控制方法应用于速度环,以改善系统抗负载扰动能力,提高容错系统鲁棒性。结果表明,该容错控制方法使得变桨系统在传感器故障情况下,牺牲部分系统性能后依然具有较理想的控制特性,并且该方法的正确性也得到了验证。%In view of the current sensors failure in electric pitch system,a variable universe fuzzy fault tolerant control method of electric pitch control system based on single current detection is proposed.When there is single or two-current sensor fault occurs,based on the proposed method the missing current information can be reconstructed by using direct current (DC)bus current sensor and the three-phase current can be updated in time within any two adjacent sampling periods,so as to ensure sta-bility of the closed-loop system.And then the switchover and fault tolerant control of fault current sensor would be accom-plished by fault diagnosis method based on adaptive threshold judgment.For the reconstructed signal error caused by the modu-lation method and the main control target of electric pitch system,a variable universe fuzzy control method is used in the speed loop,which can improve the anti-disturbance ability to load variation,and the robustness of fault tolerance system.The results show that the fault tolerant control method makes the variable pitch control system still has ideal

  12. Fault injection system for automatic testing system

    Institute of Scientific and Technical Information of China (English)

    王胜文; 洪炳熔

    2003-01-01

    Considering the deficiency of the means for confirming the attribution of fault redundancy in the re-search of Automatic Testing System(ATS) , a fault-injection system has been proposed to study fault redundancyof automatic testing system through compurison. By means of a fault-imbeded environmental simulation, thefaults injected at the input level of the software are under test. These faults may induce inherent failure mode,thus bringing about unexpected output, and the anticipated goal of the test is attained. The fault injection con-sists of voltage signal generator, current signal generator and rear drive circuit which are specially developed,and the ATS can work regularly by means of software simulation. The experimental results indicate that the faultinjection system can find the deficiency of the automatic testing software, and identify the preference of fault re-dundancy. On the other hand, some soft deficiency never exposed before can be identified by analyzing the tes-ting results.

  13. The optimization of global fault tolerant trajectory for redundant manipulator based on self-motion

    Directory of Open Access Journals (Sweden)

    Zhang Jian

    2015-01-01

    Full Text Available The redundancy feature of manipulators provides the possibility for the fault tolerant trajectory planning. Aiming at the completion of the specific task, an algorithm of global fault tolerant trajectory optimization for redundant manipulator based on the self-motion is proposed in this paper. Firstly, inverse kinematics equation of single redundancy manipulator based on self-motion variable and null-space velocity array of Jacobian are analyzed. Secondly, the mathematical description of fault tolerance criteria of the configuration of manipulator is established and the fault tolerance configuration group of manipulator is obtained by using iteration traversal under the fault tolerance criteria. Then, considering the joint limits and minimum the energy consumption as the optimization target, the global fault tolerant joint trajectory is achieved. Finally, simulation for 7 degree of freedom (DOF manipulator is performed, by which the effectiveness of the algorithm is validated.

  14. Subaru FATS (fault tracking system)

    Science.gov (United States)

    Winegar, Tom W.; Noumaru, Junichi

    2000-07-01

    The Subaru Telescope requires a fault tracking system to record the problems and questions that staff experience during their work, and the solutions provided by technical experts to these problems and questions. The system records each fault and routes it to a pre-selected 'solution-provider' for each type of fault. The solution provider analyzes the fault and writes a solution that is routed back to the fault reporter and recorded in a 'knowledge-base' for future reference. The specifications of our fault tracking system were unique. (1) Dual language capacity -- Our staff speak both English and Japanese. Our contractors speak Japanese. (2) Heterogeneous computers -- Our computer workstations are a mixture of SPARCstations, Macintosh and Windows computers. (3) Integration with prime contractors -- Mitsubishi and Fujitsu are primary contractors in the construction of the telescope. In many cases, our 'experts' are our contractors. (4) Operator scheduling -- Our operators spend 50% of their work-month operating the telescope, the other 50% is spent working day shift at the base facility in Hilo, or day shift at the summit. We plan for 8 operators, with a frequent rotation. We need to keep all operators informed on the current status of all faults, no matter the operator's location.

  15. Fault-Tolerant Visual Secret Sharing Schemes without Pixel Expansion

    Directory of Open Access Journals (Sweden)

    Justie Su-Tzu Juan

    2016-01-01

    Full Text Available Visual cryptography encrypts a secret image into two meaningless random images, called shares, such that it can be decrypted by human vision without any calculations. However, there would be problems in alignment when these two shares are staked by hand in practice. Therefore, this paper presents the fault-tolerant schemes of stacking two shares that are acquired from secret image encryption without pixel expansion. The main idea of these schemes is to combine several pixels as a unit and then to encrypt each unit into a specific combination of pixels. Both theoretical analysis and simulation results demonstrate the effectiveness and practicality of the proposed schemes.

  16. Data center networks topologies, architectures and fault-tolerance characteristics

    CERN Document Server

    Liu, Yang; Veeraraghavan, Malathi; Lin, Dong; Hamdi, Mounir

    2013-01-01

    This SpringerBrief presents a survey of data center network designs and topologies and compares several properties in order to highlight their advantages and disadvantages. The brief also explores several routing protocols designed for these topologies and compares the basic algorithms to establish connections, the techniques used to gain better performance, and the mechanisms for fault-tolerance. Readers will be equipped to understand how current research on data center networks enables the design of future architectures that can improve performance and dependability of data centers. This con

  17. Performance modeling of fault-tolerant circuit-switched communication networks

    OpenAIRE

    Safaei, F.; Khonsari, A.; Fathy, M.; Alzeidi, N.; Ould-Khaoua, M.

    2006-01-01

    Circuit switching (CS) has been suggested as an efficient switching method for supporting simultaneous communications (such as data, voice, and images) across parallel systems due to its ability to preserve both communication performance and fault-tolerant demands in such systems. In this paper we present an efficient scheme to capture the mean message latency in 2D torus with CS in the presence of faulty components. We have also conducted extensive simulation experiments, the results of whic...

  18. Fault Tolerant Control Design for the Longitudinal Aircraft Dynamics using Quantitative Feedback Theory

    OpenAIRE

    Ossmann, Daniel

    2015-01-01

    Flight control laws of modern aircraft are scheduled with respect to flight point parameters. The loss of the air data measurement system implies inevitably the loss of relevant scheduling information. A strategy to design a fault tolerant longitudinal flight control system is proposed which can accommodate the total loss of the angle of attack and the calibrated airspeed measurements. In this scenario the described robust longitudinal control law is employed ensuring a control performance ...

  19. A Vascular-Network-Based Nonuniform Hierarchical Fault-Tolerant Routing Algorithm for Wireless Sensor Networks

    OpenAIRE

    Hongbing Li; Peng Gao; Qingyu Xiong; Weiren Shi; Qiang Chen

    2012-01-01

    Fault tolerance is the key technology in wireless sensor networks which attracts many research interests. Aiming at the issue that the nodes' failures affect the network's stability and service quality, a vascular-network-based fault-tolerant routing algorithm is presented by nonuniform hierarchical clustering. According to the distribution characteristics of the vascular network and inspirations to the fault tolerance for wireless sensor networks, a mathematical model and network topology ar...

  20. Flow-Based Biochips: Fault-Tolerant Design and Error Recovery

    DEFF Research Database (Denmark)

    Pop, Paul

    2015-01-01

    expensive reagents and often hard-to-obtain samples, and can be safety critical (endangering human life), e.g., for important diagnostic procedures (screening for cancer). Researchers have started to propose fault models and test techniques for mVLSI biochips. To increase the yield, and to potentially also...... prevent the failure during the operation of the biochip, we advocate the use of fault-tolerant biochip design. The vision is to provide application fault-tolerance at run-time (online), detecting the faults as they appear, and reconfiguring the application. However, in this paper our assumption......, normally not needed for correct operation, to be used for fault-tolerance....

  1. Prognostics Enhancemend Fault-Tolerant Control with an Application to a Hovercraft Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Fault-Tolerant Control (FTC) is an emerging area of engineering and scientific research that integrates prognostics, health management concepts and intelligent...

  2. DFTSNA:A Distributed Fault—Tolerant Shipboard System

    Institute of Scientific and Technical Information of China (English)

    徐洁; 李庆南; 等

    1990-01-01

    This paper describes the architecture,fundamental principle and implementation of a distributed fault-tolerant system-DFTSNA,Its objective is o combine extreme reliability with high availability in a shipboard environment,Multi-level fault tolerance is considered and several special purpose hardware subsystems(F-T clusters)are developed.The physical and functional distribution of the system is empha-sized to meet the stringent shipboard requirements.A number of algorithms are produced to support fault-tolerant operation.

  3. Reliability Improvement of a T-Type Three-Level Inverter With Fault-Tolerant Control Strategy

    DEFF Research Database (Denmark)

    Choi, Uimin; Blaabjerg, Frede; Lee, Kyo-Beum

    2015-01-01

    This paper proposes a fault-tolerant control strategy for a T-type three-level inverter when an open-circuit fault occurs. The proposed method is explained by dividing fault into two cases: the faulty condition of half-bridge switches and neutral-point switches. In case of the open-circuit fault...... in a neutral-point switch, two methods will be proposed and compared based on thermal analysis and neutral-point voltage oscillation. The reliability of T-type inverter systems is improved considerably by the proposed algorithm when a switch fails. The proposed method does not require any additional components...

  4. Fault tolerant wind turbine production operation and shutdown (Sustainable Control)

    NARCIS (Netherlands)

    Van Engelen, T.; Schuurmans, J.; Kanev, S.; Dong, J.; Verhaegen, M.H.G.; Hayashi, Y.

    2011-01-01

    Extreme environmental conditions as well as system failure are real-life phenomena. Especially offshore, extreme environmental conditions and system faults are to be dealt with in an effective way. The project Sustainable Control, a new approach to operate wind turbines (Agentschap NL, grant EOSLT02

  5. 2009 fault tolerance for extreme-scale computing workshop, Albuquerque, NM - March 19-20, 2009.

    Energy Technology Data Exchange (ETDEWEB)

    Katz, D. S.; Daly, J.; DeBardeleben, N.; Elnozahy, M.; Kramer, B.; Lathrop, S.; Nystrom, N.; Milfeld, K.; Sanielevici, S.; Scott, S.; Votta, L.; Louisiana State Univ.; Center for Exceptional Computing; LANL; IBM; Univ. of Illinois; Shodor Foundation; Pittsburgh Supercomputer Center; Texas Advanced Computing Center; ORNL; Sun Microsystems

    2009-02-01

    This is a report on the third in a series of petascale workshops co-sponsored by Blue Waters and TeraGrid to address challenges and opportunities for making effective use of emerging extreme-scale computing. This workshop was held to discuss fault tolerance on large systems for running large, possibly long-running applications. The main point of the workshop was to have systems people, middleware people (including fault-tolerance experts), and applications people talk about the issues and figure out what needs to be done, mostly at the middleware and application levels, to run such applications on the emerging petascale systems, without having faults cause large numbers of application failures. The workshop found that there is considerable interest in fault tolerance, resilience, and reliability of high-performance computing (HPC) systems in general, at all levels of HPC. The only way to recover from faults is through the use of some redundancy, either in space or in time. Redundancy in time, in the form of writing checkpoints to disk and restarting at the most recent checkpoint after a fault that cause an application to crash/halt, is the most common tool used in applications today, but there are questions about how long this can continue to be a good solution as systems and memories grow faster than I/O bandwidth to disk. There is interest in both modifications to this, such as checkpoints to memory, partial checkpoints, and message logging, and alternative ideas, such as in-memory recovery using residues. We believe that systematic exploration of these ideas holds the most promise for the scientific applications community. Fault tolerance has been an issue of discussion in the HPC community for at least the past 10 years; but much like other issues, the community has managed to put off addressing it during this period. There is a growing recognition that as systems continue to grow to petascale and beyond, the field is approaching the point where we don

  6. A learning system for fault finding

    OpenAIRE

    Tunevi, Anders

    1989-01-01

    A learning system for fault finding has been constructed. This system contains many different types of knowledge, three ways to find faults and four ways to learn fault finding. The constructed learning system works for a class of fault finding problems. This class has been described in the paper. The developed system could be viewed as an architecture of a general learning system for fault finding. The system could also be used as a testbench of learning mechanisms. The experiences from this...

  7. Checkpoint and Replication Oriented Fault Tolerant Mechanism for MapReduce Framework

    Directory of Open Access Journals (Sweden)

    Yang Liu

    2013-09-01

    Full Text Available MapReduce is an emerging programming paradigm and an associated implementation for processing and generating big data which has been widely applied in data-intensive systems. In cloud environment, node and task failure is no longer accidental but a common feature of large-scale systems. In MapReduce framework, although the rescheduling based fault-tolerant method is simple to implement, it failed to fully consider the location of distributed data, the computation and storage overhead. Thus, a single node failure will increase the completion time dramatically. In this paper, a Checkpoint and Replication Oriented Fault Tolerant scheduling algorithm (CROFT is proposed, which takes both task and node failure into consideration. Preliminary experiments show that with less storage and network overhead. CROFT will significantly reduce the completion time at failure time, and the overall performance of MapReduce can be improved at least over 30% than original mechanism in Hadoop.  

  8. Fault Tolerant Algorithm Based on Dynamic and Active Load Balancing for Redundant Services

    Institute of Scientific and Technical Information of China (English)

    Jun-Feng Tian; Jun-Wei Zhang; Feng-Xian Wang

    2004-01-01

    A new Some-Read-Any-Write (SRAW) fault tolerant algorithm for redundant services is presented that allows a system to adjust failures dynamically in order to keep the availability and improve the performance. SRAW is based upon dynamic and active load balancing. By introducing dynamic and active load balancing scheme into redundant services, not only the processing speed of requests can be greatly improved, but also the load balancing can be simply and efficiently achieved. Integrated with consistency protocol in this paper, SRAW can also be applied to state services. The performance of SRAW algorithm is also analyzed, and comparisons with other fault tolerant algorithms, especially with RAWA, indicate that SRAW efficiently improves the performance of redundant services with guaranteeing system availability.

  9. The Design and Reliability Analysis of the Self-organizing Fault-tolerant System%自组织容错系统的设计及其可靠性分析

    Institute of Scientific and Technical Information of China (English)

    巨政权; 满梦华; 原亮

    2012-01-01

    以生物神经系统的容错机理为基础,借鉴传统的人工神经网络的构建方式,结合电子电路的构造特点,提出了一种自组织神经网络模型,构建了自组织容错系统,并对构建的容错系统建立可靠性模型.通过可靠性分析发现,对于同功能不同拓扑的承载电路,当其占用神经元越少、在各层上分布越均匀时,其可靠性越高.%The self-organizing neural networks model was proposed based on the fault-tolerant mechanism of the biological nervous system,the structure characteristic of the traditional artificial neural network and the electronic circuit,and then the self-organizing Fault-tolerant System and its reliability model were constructed.Through dependability analyzed,we found that the fewer the cell in the circuit,and the more evenly to distribute on every floor,the higher of its dependability.

  10. A Simple Fault-Tolerant Adaptive and Minimal Routing Approach in 3-D Meshes

    Institute of Scientific and Technical Information of China (English)

    WU Jie(吴杰)

    2003-01-01

    In this paper we propose a sufficient condition for minimal routing in 3-dimensional (3-D) meshes with faulty nodes. It is based on an early work of the author on minimal routing in 2-dimensional (2-D) meshes. Unlike many traditional models that assume all the nodes know global fault distribution or just adjacent fault information, our approach is based on the concept of limited global fault information. First, we propose a fault model called faulty cube in which all faulty nodes in the system are contained in a set of faulty cubes. Fault information is then distributed to limited number of nodes while it is still sufficient to support minimal routing. The limited fault information collected at each node is represented by a vector called extended safety level. The extended safety level associated with a node can be used to determine the existence of a minimal path from this node to a given destination. Specifically, we study the existence of minimal paths at a given source node, limited distribution of fault information, minimal routing, and deadlock-free and livelock-free routing. Our results show that any minimal routing that is partially adaptive can be applied in our model as long as the destination node meets a certain condition. We also propose a dynamic planar-adaptive routing scheme that offers better fault tolerance and adaptivity than the planar-adaptive routing scheme in 3-D meshes. Our approach is the first attempt to address adaptive and minimal routing in 3-D meshes with faulty nodes using limited fault information.

  11. Fault Detection for Nonlinear Systems

    DEFF Research Database (Denmark)

    Stoustrup, Jakob; Niemann, H.H.

    1998-01-01

    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...

  12. DSP-Based Sensor Fault Detection and Post Fault-Tolerant Control of an Induction Motor-Based Electric Vehicle

    Directory of Open Access Journals (Sweden)

    Bekheïra Tabbache

    2012-01-01

    Full Text Available This paper deals with sensor fault detection within a reconfigurable direct torque control of an induction motor-based electric vehicle. The proposed strategy concerns current, voltage, and speed sensors faults that are detected and followed by post fault-tolerant control to allow the vehicle continuous operation. The proposed approach is validated through experiments on an induction motor drive and simulations on an electric vehicle using a European urban and extraurban driving cycle.

  13. Diagnosis and Fault-tolerant Control for Ship Station Keeping

    DEFF Research Database (Denmark)

    Blanke, Mogens

    2005-01-01

    design for systems of high complexity, and also analyse the cases of cascaded or multiple faults. The paper takes as example a ship with two CP propellers, rudders and a bow thruster as actuators, and instrumentation with a suite of global position sensors, inertial navigation units and conventional gyro...

  14. Systematic Fault Tolerant Control Based on Adaptive Thau Observer Estimation for Quadrotor Uavs

    Directory of Open Access Journals (Sweden)

    Cen Zhaohui

    2015-03-01

    Full Text Available A systematic fault tolerant control (FTC scheme based on fault estimation for a quadrotor actuator, which integrates normal control, active and passive FTC and fault parking is proposed in this paper. Firstly, an adaptive Thau observer (ATO is presented to estimate the quadrotor rotor fault magnitudes, and then faults with different magnitudes and time-varying natures are rated into corresponding fault severity levels based on the pre-defined fault-tolerant boundaries. Secondly, a systematic FTC strategy which can coordinate various FTC methods is designed to compensate for failures depending on the fault types and severity levels. Unlike former stand-alone passive FTC or active FTC, our proposed FTC scheme can compensate for faults in a way of condition-based maintenance (CBM, and especially consider the fatal failures that traditional FTC techniques cannot accommodate to avoid the crashing of UAVs. Finally, various simulations are carried out to show the performance and effectiveness of the proposed method.

  15. A DYNAMIC FAULT TOLERANT ALGORITHM FOR IMPROVISING PERFORMANCE OF MULTIMEDIA SERVICES

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Multimedia Services has drawn much attention from both industrial and academic researchers due to the emerging consumer market, how to provide High-Availability service is one of most important issues to take into account. In this paper, a dynamic fault tolerant algorithm is presented for highly available distributed multimedia service, then by introducing SLB(server load balancing) into fault tolerance and switching servers in different ways according to their functions, the proposed schema can preserve reliability and real-time of the system .The analysis and experiments indicate that resuming server's faulty by this method is smooth and transparent to the client The proposed algorithm is effectively improving the reliability of the multimedia service.

  16. Fault tolerant position mooring control based on structural reliability

    OpenAIRE

    Fang, Shaoji

    2012-01-01

    Safety of position mooring system is a prime concern in the marine industry and regulations are in force to prevent faults in equipment from causing failure of the whole system. There are many reasons for failures in elements of a mooring system, e.g. material damage, overload, fatigue, brittle fracture, corrosion, abrasion, extreme environment. For mooring cables, one of the typical reasons for failure is overload due to frequent replacement and inspections. Although a design based on knowle...

  17. Plugging Braking of Two-PMSM Drive in Subway Applications with Fault-Tolerant Operation

    Directory of Open Access Journals (Sweden)

    Adel A. obed

    2016-06-01

    Full Text Available The Permanent Magnet Synchronous Motor (PMSM is commonly used as traction motors in the electric traction applications such as in subway train. The subway train is better transport vehicle due to its advantages of security, economic, health and friendly with nature. Braking is defined as removal of the kinetic energy stored in moving parts of machine. The plugging braking is the best braking offered and has the shortest time to stop. The subway train is a heavy machine and has a very high moment of inertia requiring a high braking torque to stop. The plugging braking is an effective method to provide a fast stop to the train. In this paper plugging braking system of the PMSM used in the subway train in normal and fault-tolerant operation is made. The model of the PMSM, three-phase Voltage Source Inverter (VSI controlled using Space Vector Pulse Width Modulation technique (SVPWM, Field Oriented Control method (FOC for independent control of two identical PMSMs and fault-tolerant operation is presented. Simulink model of the plugging braking system of PMSM in normal and fault tolerant operation is proposed using Matlab/Simulink software. Simulation results for different cases are given.

  18. Fault tolerant workflow scheduling based on replication and resubmission of tasks in Cloud Computing

    Directory of Open Access Journals (Sweden)

    Jayadivya S K

    2012-06-01

    Full Text Available The aim of workflow scheduling system is to schedule the workflows within the user given deadline to achieve a good success rate. Workflow is a set of tasks processed in a predefined order based on its data and control dependency. Scheduling these workflows in a computing environment, like cloud environment, is an NP-Complete problem and it becomes more challenging when failures of tasks areconsidered. To overcome these failures, the workflow scheduling system should be fault tolerant. In this paper, the proposed Fault Tolerant Workflow Scheduling algorithm (FTWS provides fault tolerance by using replication and resubmission of tasks based on priority of the tasks. The replication of tasks depends on a heuristic metric which is calculated by finding the tradeoff between the replication factor and resubmission factor. The heuristic metric is considered because replication alone may lead to resource wastage and resubmission alone may increase makespan. Tasks are prioritized based on the criticality of the task which is calculated by using parameters like out degree, earliest deadline and high resubmission impact. Priority helps in meeting the deadline of a task and thereby reducing wastage of resources. FTWS schedules workflows within a deadline even in the presence of failures without using any history of information. The experiments were conducted in a simulated cloud environment by scheduling workflows in the presence of failures which are generated randomly. The experimental results of the proposed work demonstrate the effective success rate in-spite of various failures.

  19. Fault Tolerance Design of Frequency Conversion and Velocity Modulation Multi-CPU Control Computer System%变频调速多CPU控制计算机系统的容错设计

    Institute of Scientific and Technical Information of China (English)

    刘成印; 马鹏祥; 徐红春

    2001-01-01

    According to the control characteristics of cycloconverter, this paper proposes a new multi-CPU computer control system. This architecture consists of self-diagnosis, fault-tolerance and multi-CPU computer control technology. Not only is reliability of computer control system improved, but also more complicated system control strategy can be realized.%根据交-交变频器的控制特性,提出了较为新颖的多CPU计算机控制系统结构。该结构集自诊断、容错、多CPU控制技术于一体,不但提高了计算机控制系统的可靠性,而且可实现较为复杂的系统控制策略。

  20. Fault-tolerant topology in the wireless sensor networks for energy depletion and random failure

    International Nuclear Information System (INIS)

    Nodes in the wireless sensor networks (WSNs) are prone to failure due to energy depletion and poor environment, which could have a negative impact on the normal operation of the network. In order to solve this problem, in this paper, we build a fault-tolerant topology which can effectively tolerate energy depletion and random failure. Firstly, a comprehensive failure model about energy depletion and random failure is established. Then an improved evolution model is presented to generate a fault-tolerant topology, and the degree distribution of the topology can be adjusted. Finally, the relation between the degree distribution and the topological fault tolerance is analyzed, and the optimal value of evolution model parameter is obtained. Then the target fault-tolerant topology which can effectively tolerate energy depletion and random failure is obtained. The performances of the new fault tolerant topology are verified by simulation experiments. The results show that the new fault tolerant topology effectively prolongs the network lifetime and has strong fault tolerance. (general)

  1. A Semantics-Based Approachfor Achieving Self Fault-Tolerance of Protocols

    Institute of Scientific and Technical Information of China (English)

    李腊元; 李春林

    2000-01-01

    The cooperation of different processes may be lost by mistake when a protocol is executed. The protocol cannot be normally operated under this condition. In this paper, the self fault-tolerance of protocols is discussed, and a semanticsbased approach for achieving self fault-tolerance of protocols is presented. Some main characteristics of self fault-tolerance of protocols concerning liveness, nontermination and infinity are also presented. Meanwhile, the sufficient and necessary conditions for achieving self fault-tolerance of protocols are given. Finally, a typical protocol that does not satisfy the self fault-tolerance is investigated, and a new redesign version of this existing protocol using the proposed approach is given.

  2. Design of Parity Preserving Logic Based Fault Tolerant Reversible Arithmetic Logic Unit

    Directory of Open Access Journals (Sweden)

    Rakshith Saligram1

    2013-06-01

    Full Text Available Reversible Logic is gaining significant consideration as the potential logic design style for implementation in modern nanotechnology and quantum computing with minimal impact on physical entropy .Fault Tolerant reversible logic is one class of reversible logic that maintain the parity of the input and the outputs. Significant contributions have been made in the literature towards the design of fault tolerant reversible logic gate structures and arithmetic units, however, there are not many efforts directed towards the design of fault tolerant reversible ALUs. Arithmetic Logic Unit (ALU is the prime performing unit in any computing device and it has to be made fault tolerant. In this paper we aim to design one such fault tolerant reversible ALU that is constructed using parity preserving reversible logic gates. The designed ALU can generate up to seven Arithmetic operations and four logical operations

  3. Ultrafast and fault-tolerant quantum communication across long distances.

    Science.gov (United States)

    Muralidharan, Sreraman; Kim, Jungsang; Lütkenhaus, Norbert; Lukin, Mikhail D; Jiang, Liang

    2014-06-27

    Quantum repeaters (QRs) provide a way of enabling long distance quantum communication by establishing entangled qubits between remote locations. In this Letter, we investigate a new approach to QRs in which quantum information can be faithfully transmitted via a noisy channel without the use of long distance teleportation, thus eliminating the need to establish remote entangled links. Our approach makes use of small encoding blocks to fault-tolerantly correct both operational and photon loss errors. We describe a way to optimize the resource requirement for these QRs with the aim of the generation of a secure key. Numerical calculations indicate that the number of quantum memory bits at each repeater station required for the generation of one secure key has favorable polylogarithmic scaling with the distance across which the communication is desired. PMID:25014798

  4. Incorporating Fault Tolerance in LEACH Protocol for Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Rudranath Mitra

    2012-06-01

    Full Text Available Routing protocols have been a challenging issue in wireless sensor networks. WSN is one of the focussed are of research because of its multi-aspect applications. These networks are self-organized using clustering algorithms to conserve energy. LEACH (Low-Energy Adaptive Clustering Hierarchy protocol[1] is one of the significant protocols for routing in WSN. In LEACH, sensor nodes are organized in several small clusters where there are cluster heads in each cluster. These CHs gather data from their local clusters aggregate them & send them to the base station. On the LEACH many new schemes have been proposed to enhance its activity like its efficiency, security etc. In this paper the fault tolerance issue is being incorporated.

  5. Fault-Tolerant Energy-Efficient Tree in Dynamic WSNs

    Directory of Open Access Journals (Sweden)

    Tarek Moulahi

    2013-04-01

    Full Text Available Broadcasting has a main importance in Wireless Sens or Networks (WSNs. Effectively, the sink node has to collect periodically, data from the environment supervised by sensors. To perform this operation, i t sends requests to all nodes. Furthermore, WSNs have a dynamic behaviour due to their evolution. At any time, a node can be retrieved from the network due to an exhausting energy or a node problem. In fac t, WSNs are prone to failure such as software o r hardware malfunctioning, exhaustion of energy, wireless interference and environmental hazards. Thus, an appropriate broadcasting method should take into consideration this aspect and uses the le ss possible amount of energy to accomplish the task . In this paper, a robust tree-based scheme is proposed which is called Robust Tree Broadcasting (RTB. The new scheme has a load-balanced behaviour which indu ces an efficient use of energy. In addition, RTB has a high-quality fault tolerant performance.

  6. Certifying qubit operations below the fault tolerance threshold

    CERN Document Server

    Blume-Kohout, Robin; Nielsen, Erik; Rudinger, Kenneth; Mizrahi, Jonathan; Fortier, Kevin; Maunz, Peter

    2016-01-01

    Quantum information processors promise fast algorithms for problems inaccessible to classical computers. But since qubits are noisy and error-prone, they will depend on fault-tolerant quantum error correction (FTQEC) to compute reliably. Quantum error correction can protect against general noise if -- and only if -- the error in each physical qubit operation is smaller than a certain threshold. The threshold for general errors is quantified by their diamond norm. Until now, qubits have been assessed primarily by randomized benchmarking (RB), which reports a different "error rate" that is not sensitive to all errors, cannot be compared directly to diamond norm thresholds, and cannot efficiently certify a qubit for FTQEC. We use gate set tomography (GST) to completely characterize the performance of a trapped-Yb$^+$-ion qubit and certify it rigorously as suitable for FTQEC by establishing that its diamond norm error rate is less than $6.7\\times10^{-4}$ with $95\\%$ confidence.

  7. Data Structures: Sequence Problems, Range Queries, and Fault Tolerance

    DEFF Research Database (Denmark)

    Jørgensen, Allan Grønlund

    for several variants of the problem based on a simple idea and classic algorithms and data structures. In Part II we consider range query data structures. This a category of problems where the task is to preprocess an input sequence using as little time and space as possible such that one can eciently compute......The focus of this dissertation is on algorithms, in particular data structures that give provably ecient solutions for sequence analysis problems, range queries, and fault tolerant computing. The work presented in this dissertation is divided into three parts. In Part I we consider algorithms...... for a range of sequence analysis problems that have risen from applications in pattern matching, bioinformatics, and data mining. On a high level, each problem is dened by a function and some constraints and the job at hand is to locate subsequences that score high with this function and are not invalidated...

  8. Fault Tolerance Mechanism in Chip Many-Core Processors

    Institute of Scientific and Technical Information of China (English)

    ZHANG Lei; HAN Yinhe; LI Huawei; LI Xiaowei

    2007-01-01

    As semiconductor technology advances, there will be billions of transistors on a single chip. Chip many-core processors are emerging to take advantage of these greater transistor densities to deliver greater performance. Effective fault tolerance techniques are essential to improve the yield of such complex chips. In this paper, a core-level redundancy scheme called N+M is proposed to improve N-core processors'yield by providing M spare cores. In such architecture, topology is an important factor because it greatly affects the processors'performance. The concept of logical topology and a topology reconfiguration problem are introduced, which is able to transparently provide target topology with lowest performance degradation as the presence of faulty cores on-chip. A row rippling and column stealing (RRCS) algorithm is also proposed. Results show that PRCS can give solutions with average 13.8% degradation with negligible computing time.

  9. Fault Tolerant Distributed and Fixed Hierarchical Mobile IP

    Directory of Open Access Journals (Sweden)

    Paramesh C. Upadhyay

    2010-04-01

    Full Text Available To several mobility management protocols proposed for IP-based mobile networks, faulttolerance aspect of mobility agents is a primary requirement to sustain continuous service availability to themobile hosts. For a localized or micro- mobility management solution, the local mobility agent i.e. gateway isa single point of failure because it is responsible for enforcing the signaling and data packets in its domain.Such failures may severely disrupt the communications among the failure-affected users. The problembecomes even more severe for mobility agents in a distributed mobility management scheme with overlappingregistration areas.This paper proposes a fault tolerance scheme for Distributed and Fixed Hierarchical Mobile IP(DFHMIP and evaluates its performance in terms of data transmission cost and blocking probability.

  10. Experimental magic state distillation for fault-tolerant quantum computing.

    Science.gov (United States)

    Souza, Alexandre M; Zhang, Jingfu; Ryan, Colm A; Laflamme, Raymond

    2011-01-25

    Any physical quantum device for quantum information processing (QIP) is subject to errors in implementation. In order to be reliable and efficient, quantum computers will need error-correcting or error-avoiding methods. Fault-tolerance achieved through quantum error correction will be an integral part of quantum computers. Of the many methods that have been discovered to implement it, a highly successful approach has been to use transversal gates and specific initial states. A critical element for its implementation is the availability of high-fidelity initial states, such as |0〉 and the 'magic state'. Here, we report an experiment, performed in a nuclear magnetic resonance (NMR) quantum processor, showing sufficient quantum control to improve the fidelity of imperfect initial magic states by distilling five of them into one with higher fidelity.

  11. GEARSHIFT: Guaranteeing availability requirements in SLAs using hybrid fault tolerance

    OpenAIRE

    Gonzalez, Andres Javier; Helvik, Bjarne Emil; Tiwari, Prakriti; Denis, Becker; Wittner, Otto Jonassen

    2015-01-01

    The dependability of ICT systems is vital for today's society. However, operational systems are not fault free. Providers and customers have to define clear availability requirements and penalties on the delivered services by using SLAs. Fulfilling the stipulated availability may be expensive. The lack of mechanisms that allow a fine control of the SLA risk may lead to over-dimension the provided resources. Therefore, a relevant question for ICT service providers is: How to guarantee the SLA ...

  12. Review of fault diagnosis and fault-tolerant control for modular multilevel converter of HVDC

    DEFF Research Database (Denmark)

    Liu, Hui; Loh, Poh Chiang; Blaabjerg, Frede

    2013-01-01

    This review focuses on faults in Modular Multilevel Converter (MMC) for use in high voltage direct current (HVDC) systems by analyzing the vulnerable spots and failure mechanism from device to system and illustrating the control & protection methods under failure condition. At the beginning, seve...

  13. A TESTING FRAMEWORK FOR FAULT TOLERANT COMPOSITION OF TRANSACTIONAL WEB SERVICES

    OpenAIRE

    Deepali Diwase; Pujashree Vidap

    2012-01-01

    Software testers have great challenges in testing of web services therefore testing technique must be developed for testing of web services. Web service composition is an active research area over last few years. This paper proposes a framework for testing of fault tolerant composition of web services. It will tolerate faults whilecomposition of web services. Exception handling and transaction techniques are used as fault handling mechanisms. After composition web services are deployed on WS-...

  14. Fault-tolerant digital microfluidic biochips compilation and synthesis

    CERN Document Server

    Pop, Paul; Stuart, Elena; Madsen, Jan

    2016-01-01

    This book describes for researchers in the fields of compiler technology, design and test, and electronic design automation the new area of digital microfluidic biochips (DMBs), and thus offers a new application area for their methods.  The authors present a routing-based model of operation execution, along with several associated compilation approaches, which progressively relax the assumption that operations execute inside fixed rectangular modules.  Since operations can experience transient faults during the execution of a bioassay, the authors show how to use both offline (design time) and online (runtime) recovery strategies. The book also presents methods for the synthesis of fault-tolerant application-specific DMB architectures. ·         Presents the current models used for the research on compilation and synthesis techniques of DMBs in a tutorial fashion; ·         Includes a set of “benchmarks”, which are presented in great detail and includes the source code of most of the t...

  15. Novel approach to fault-tolerant logic and yield enhancement

    Energy Technology Data Exchange (ETDEWEB)

    Takefuji, Y.; Adachi, Y.; Aiso, H.

    1982-01-01

    A design technique for improving reliability in function of a gate is proposed, in which a plurality of conventional logic circuits (gates) are used so as to give redundancy to a logic circuit itself. The gate with redundancy designed on the basis of the proposed technique is called the fault-tolerant gate (FTG) in this paper. The FTG has a recovery function with respect to a wider variety of faults. It is much more powerful than that offered by the TMR (triple modular redundancy) circuits. Therefore, the highly reliable logic circuits can be realized, and when the concept of FTGs is applied to vlsi chips the production yield must be enhanced. This paper is divided into three parts. In the first part, concrete methods to realize FTGs are described. The second part proves that the reliability of the gates can be improved by employing the concept of FTGs. In the last part, it is shown that the FTG contributes to the yield enhancement of vlsi chips. 13 references.

  16. Comparing fault susceptibility of multiple ISAs and operating systems

    Science.gov (United States)

    Chyłek, Sławomir

    2015-09-01

    This paper presents a research that aims to compare effects of faults on different configurations of computer systems. The study covers comparison of susceptibility to faults of x86, AMD64, ARM, PowerPC, MIPS architectures and Linux, FreeBSD, Minix operating systems. An emulation based software implemented fault injection technique was used to perform experiments. The problem of choosing an adequate number of tests in experiments is followed by report with collected results where multiple aspects of test runs were analyzed: providing correct computation result, availability of the system under test and error messages. The research allows to determine characteristics of susceptibility to faults of each platform and is a first step towards designing new fault tolerance solutions and assessing their effectiveness.

  17. Transient Faults in Computer Systems

    Science.gov (United States)

    Masson, Gerald M.

    1993-01-01

    A powerful technique particularly appropriate for the detection of errors caused by transient faults in computer systems was developed. The technique can be implemented in either software or hardware; the research conducted thus far primarily considered software implementations. The error detection technique developed has the distinct advantage of having provably complete coverage of all errors caused by transient faults that affect the output produced by the execution of a program. In other words, the technique does not have to be tuned to a particular error model to enhance error coverage. Also, the correctness of the technique can be formally verified. The technique uses time and software redundancy. The foundation for an effective, low-overhead, software-based certification trail approach to real-time error detection resulting from transient fault phenomena was developed.

  18. Fault tolerant model predictive control of open channels

    OpenAIRE

    Horváth, Klaudia; Blesa Izquierdo, Joaquim; Duviella, Eric; Chuquet, Karine

    2014-01-01

    Automated control of water systems (irrigation canals, navigation canals, rivers etc.) relies on the measured data. The control action is calculated, in case of feedback controller, directly from the on-line measured data. If the measured data is corrupted, the calculated control action will have a different effect than it is desired. Therefore, it is crucial that the feedback controller receives good quality measurement data. On-line fault detection techniques can be applied in order to dete...

  19. A New Adaptive Kalman Estimator for Detection and Isolation of Multiple Faults Integrated in a Fault Tolerant Control

    Directory of Open Access Journals (Sweden)

    H. Jamouli

    2010-01-01

    Full Text Available For sequential jumps detection, isolation, and estimation in discrete-time stochastic linear systems, Willsky and Jones (1976 have developed the Generalized Likelihood Ratio (GLR test. After each detection and isolation of one jump, the treatment of another possible jump is obtained by a direct state estimate and covariance incrementation of the Kalman filter originally designed on the jump-free system. This paper proposes to extend this approach from a state estimator designed on a reference model directly sensitive to system changes. We will show that the obtained passive GLR test can be easily integrated in a Fault Tolerant Control System (FTCS via a control law designed in order to asymptotically reject the effect of sequential jumps.

  20. AVR microcontroller simulator for software implemented hardware fault tolerance algorithms research

    Science.gov (United States)

    Piotrowski, Adam; Tarnowski, Szymon; Napieralski, Andrzej

    2008-01-01

    Reliability of new, advanced electronic systems becomes a serious problem especially in places like accelerators and synchrotrons, where sophisticated digital devices operate closely to radiation sources. One of the possible solutions to harden the microprocessor-based system is a strict programming approach known as the Software Implemented Hardware Fault Tolerance. Unfortunately, in real environments it is not possible to perform precise and accurate tests of the new algorithms due to hardware limitation. This paper highlights the AVR-family microcontroller simulator project equipped with an appropriate monitoring and the SEU injection systems.

  1. Fault Tolerant Three-Phase AC Motor Drive Topologies: A Comparison of Features, Cost, and Limitations (To Continue)

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    C. Phase-Redundant Topology The ability to isolate a faulty phase-leg opens the possibility of introducing a spare inverter leg for improved fault tolerance as shown in Fig.8. The configuration will be referred to as the phase-redundant topology. This circuit topology incorporates the fault isolating SCRs and fuses in only the three active legs of the inverter. A spare fourth leg of the inverter is connected in place of the faulty phase-leg after the fault isolating devices have removed that leg from the system.

  2. Fault-tolerant scheduling algorithm with the load factor in Cyber-Physical Systems heterogeneous distributed real-time systems%CPS异构分布实时系统中带负载因子的容错调度

    Institute of Scientific and Technical Information of China (English)

    符利华; 张立臣

    2011-01-01

    This paper introduced the newest issue-Cyber-Physical Systems (CPS) and some basic contents of Cyber-Physical Systems. And then,it gave a heterogeneous distributed real-time task system model in the Cyber-Physical Systems. Based on this model and the primary-backup technology ,this paper proposed two fault-tolerant scheduling algorithms,which adapt to the heterogeneous distributed real-time environment of Cyber-Physical Systems:HDLMA (Heterogeneous Distributed Min Loading Algorithm) and H DLFA (Heterogeneous Distributed Loading Factor Algorithm). Finally,this paper analyzed their schedulability,load balancing,the influence of the granularity of tasks on load balancing as well as how scheduling threshold affects the schedulability.%介绍了Cyber-Physical Systems的基本内容,给出了基于Cyber-Physical Systems异构分布式中的实时任务系统模型.并在该模型下结合基/副版本备份技术提出了两种适应于Cyber-Physical Systems异构分布式实时环境的启发式容错调度算法:HDLMA算法和HDLFA算法.最后针对这两种算法,分析了算法可调度性,负载均衡性,任务粒度大小对负载均衡性的影响,以及调度闽值对算法可调度性的影响.

  3. LQCD workflow execution framework: Models, provenance and fault-tolerance

    Science.gov (United States)

    Piccoli, Luciano; Dubey, Abhishek; Simone, James N.; Kowalkowlski, James B.

    2010-04-01

    Large computing clusters used for scientific processing suffer from systemic failures when operated over long continuous periods for executing workflows. Diagnosing job problems and faults leading to eventual failures in this complex environment is difficult, specifically when the success of an entire workflow might be affected by a single job failure. In this paper, we introduce a model-based, hierarchical, reliable execution framework that encompass workflow specification, data provenance, execution tracking and online monitoring of each workflow task, also referred to as participants. The sequence of participants is described in an abstract parameterized view, which is translated into a concrete data dependency based sequence of participants with defined arguments. As participants belonging to a workflow are mapped onto machines and executed, periodic and on-demand monitoring of vital health parameters on allocated nodes is enabled according to pre-specified rules. These rules specify conditions that must be true pre-execution, during execution and post-execution. Monitoring information for each participant is propagated upwards through the reflex and healing architecture, which consists of a hierarchical network of decentralized fault management entities, called reflex engines. They are instantiated as state machines or timed automatons that change state and initiate reflexive mitigation action(s) upon occurrence of certain faults. We describe how this cluster reliability framework is combined with the workflow execution framework using formal rules and actions specified within a structure of first order predicate logic that enables a dynamic management design that reduces manual administrative workload, and increases cluster-productivity.

  4. Fault Tolerant Flight Control Using Sliding Modes and Subspace Identification-Based Predictive Control

    KAUST Repository

    Siddiqui, Bilal A.

    2016-07-26

    In this work, a cascade structure of a time-scale separated integral sliding mode and model predictive control is proposed as a viable alternative for fault-tolerant control. A multi-variable sliding mode control law is designed as the inner loop of the flight control system. Subspace identification is carried out on the aircraft in closed loop. The identified plant is then used for model predictive controllers in the outer loop. The overall control law demonstrates improved robustness to measurement noise, modeling uncertainties, multiple faults and severe wind turbulence and gusts. In addition, the flight control system employs filters and dead-zone nonlinear elements to reduce chattering and improve handling quality. Simulation results demonstrate the efficiency of the proposed controller using conventional fighter aircraft without control redundancy.

  5. Fault-Tolerant Region-Based Control of an Underwater Vehicle with Kinematically Redundant Thrusters

    Directory of Open Access Journals (Sweden)

    Zool H. Ismail

    2014-01-01

    Full Text Available This paper presents a new control approach for an underwater vehicle with a kinematically redundant thruster system. This control scheme is derived based on a fault-tolerant decomposition for thruster force allocation and a region control scheme for the tracking objective. Given a redundant thruster system, that is, six or more pairs of thrusters are used, the proposed redundancy resolution and region control scheme determine the number of thruster faults, as well as providing the reference thruster forces in order to keep the underwater vehicle within the desired region. The stability of the presented control law is proven in the sense of a Lyapunov function. Numerical simulations are performed with an omnidirectional underwater vehicle and the results of the proposed scheme illustrate the effectiveness in terms of optimizing the thruster forces.

  6. Fault tolerant motion planning based on joint torque limit for redundant manipulators

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    First, two fault tolerant planning algorithms with avoidance of joint static torque limit or joint dynamic torque limit are proposed respectively. The former is suitable for the low-speed manipulators, and the latter is suitable for the high-speed manipulators. These algorithms not only can insure manipulation tasks to lie within the fault tolerant workspace but also can avoid joint torque limit, and hence can insure a redundant manipulator to be fault tolerant in both kinematical sense and dynamic sense. Then, the simulation examples for a planar 3R manipulator demonstrate the validity of these algorithms.

  7. Fault-tolerant measurement-based quantum computing with continuous-variable cluster states.

    Science.gov (United States)

    Menicucci, Nicolas C

    2014-03-28

    A long-standing open question about Gaussian continuous-variable cluster states is whether they enable fault-tolerant measurement-based quantum computation. The answer is yes. Initial squeezing in the cluster above a threshold value of 20.5 dB ensures that errors from finite squeezing acting on encoded qubits are below the fault-tolerance threshold of known qubit-based error-correcting codes. By concatenating with one of these codes and using ancilla-based error correction, fault-tolerant measurement-based quantum computation of theoretically indefinite length is possible with finitely squeezed cluster states.

  8. Design and Analysis of Software fault-Tolerant techniques for Softcore processors in reliable SRAM based FPGA

    Directory of Open Access Journals (Sweden)

    Vatsya Tiwari

    2011-11-01

    Full Text Available This paper discusses high level techniques for designing fault tolerant systems in SRAM-based FPGAs, without modification in the FPGA architecture. Triple Modular Redundancy (TMR has been successfully applied in FPGAs to mitigate transient faults, which are likely to occur in space applications. However, TMR comes with high area and power dissipation penalties. The new technique proposed in this paper was specifically developed for FPGAs to cope with transient faults in the user combinational and sequential logic, while also reducing pin count, area and power dissipation. The methodology was validated by fault injection experiments in an emulation board. We present some fault coverage results and a comparison with the TMR approach

  9. Dual-quaternion based fault-tolerant control for spacecraft formation flying with finite-time convergence.

    Science.gov (United States)

    Dong, Hongyang; Hu, Qinglei; Ma, Guangfu

    2016-03-01

    Study results of developing control system for spacecraft formation proximity operations between a target and a chaser are presented. In particular, a coupled model using dual quaternion is employed to describe the proximity problem of spacecraft formation, and a nonlinear adaptive fault-tolerant feedback control law is developed to enable the chaser spacecraft to track the position and attitude of the target even though its actuator occurs fault. Multiple-task capability of the proposed control system is further demonstrated in the presence of disturbances and parametric uncertainties as well. In addition, the practical finite-time stability feature of the closed-loop system is guaranteed theoretically under the designed control law. Numerical simulation of the proposed method is presented to demonstrate the advantages with respect to interference suppression, fast tracking, fault tolerant and practical finite-time stability. PMID:26775087

  10. Fault Tolerance Approach in Mobile Agents for Information Retrieval Applications Using Check Points

    Directory of Open Access Journals (Sweden)

    Rahul Hans

    2012-06-01

    Full Text Available Mobile agents have emerged as major programming paradigm for distributed applications. Mobile agents are the intelligent programs that act autonomously on behalf of a user and can migrate from one host to another host in a network in order to satisfy the requests made by their clients. A prerequisite for their use, however, is that they should be executed reliably independent of failures. Improving the survivability of mobile agents in presence of agent server failures is an important issue in order to guarantee continuous execution of mobile agents. Thus it is very important to make mobile agents fault tolerant. In this paper, we propose fault tolerance mechanism for the scenarios where the agent stops its execution due to fault on any server in the itinerary. Our approach makes use of check pointing, partial results or data retrieved and the address of last host visited is saved prior before the agent visits the next host in the itinerary .The proposed mechanism has been implemented on the Aglets mobile agent system and evaluated in terms of parameters such as round trip time, Reliable migration time, Check point time. The results show the improvement in reliability and performance, especially for mobile agents in Internet application.

  11. Fault-tolerant authenticated quantum dialogue using logical Bell states

    Science.gov (United States)

    Ye, Tian-Yu

    2015-09-01

    Two fault-tolerant authenticated quantum dialogue protocols are proposed in this paper by employing logical Bell states as the quantum resource, which combat the collective-dephasing noise and the collective-rotation noise, respectively. The two proposed protocols each can accomplish the mutual identity authentication and the dialogue between two participants simultaneously and securely over one kind of collective noise channels. In each of two proposed protocols, the information transmitted through the classical channel is assumed to be eavesdroppable and modifiable. The key for choosing the measurement bases of sample logical qubits is pre-shared privately between two participants. The Bell state measurements rather than the four-qubit joint measurements are adopted for decoding. The two participants share the initial states of message logical Bell states with resort to the direct transmission of auxiliary logical Bell states so that the information leakage problem is avoided. The impersonation attack, the man-in-the-middle attack, the modification attack and the Trojan horse attacks from Eve all are detectable.

  12. Fault-tolerant quantum blind signature protocols against collective noise

    Science.gov (United States)

    Zhang, Ming-Hui; Li, Hui-Fang

    2016-10-01

    This work proposes two fault-tolerant quantum blind signature protocols based on the entanglement swapping of logical Bell states, which are robust against two kinds of collective noises: the collective-dephasing noise and the collective-rotation noise, respectively. Both of the quantum blind signature protocols are constructed from four-qubit decoherence-free (DF) states, i.e., logical Bell qubits. The initial message is encoded on the logical Bell qubits with logical unitary operations, which will not destroy the anti-noise trait of the logical Bell qubits. Based on the fundamental property of quantum entanglement swapping, the receiver simply performs two Bell-state measurements (rather than four-qubit joint measurements) on the logical Bell qubits to verify the signature, which makes the protocols more convenient in a practical application. Different from the existing quantum signature protocols, our protocols can offer the high fidelity of quantum communication with the employment of logical qubits. Moreover, we hereinafter prove the security of the protocols against some individual eavesdropping attacks, and we show that our protocols have the characteristics of unforgeability, undeniability and blindness.

  13. Fault-tolerant error correction with the gauge color code.

    Science.gov (United States)

    Brown, Benjamin J; Nickerson, Naomi H; Browne, Dan E

    2016-01-01

    The constituent parts of a quantum computer are inherently vulnerable to errors. To this end, we have developed quantum error-correcting codes to protect quantum information from noise. However, discovering codes that are capable of a universal set of computational operations with the minimal cost in quantum resources remains an important and ongoing challenge. One proposal of significant recent interest is the gauge color code. Notably, this code may offer a reduced resource cost over other well-studied fault-tolerant architectures by using a new method, known as gauge fixing, for performing the non-Clifford operations that are essential for universal quantum computation. Here we examine the gauge color code when it is subject to noise. Specifically, we make use of single-shot error correction to develop a simple decoding algorithm for the gauge color code, and we numerically analyse its performance. Remarkably, we find threshold error rates comparable to those of other leading proposals. Our results thus provide the first steps of a comparative study between the gauge color code and other promising computational architectures. PMID:27470619

  14. ALLIANCE: An architecture for fault tolerant multi-robot cooperation

    Energy Technology Data Exchange (ETDEWEB)

    Parker, L.E.

    1995-02-01

    ALLIANCE is a software architecture that facilitates the fault tolerant cooperative control of teams of heterogeneous mobile robots performing missions composed of loosely coupled, largely independent subtasks. ALLIANCE allows teams of robots, each of which possesses a variety of high-level functions that it can perform during a mission, to individually select appropriate actions throughout the mission based on the requirements of the mission, the activities of other robots, the current environmental conditions, and the robot`s own internal states. ALLIANCE is a fully distributed, behavior-based architecture that incorporates the use of mathematically modeled motivations (such as impatience and acquiescence) within each robot to achieve adaptive action selection. Since cooperative robotic teams usually work in dynamic and unpredictable environments, this software architecture allows the robot team members to respond robustly, reliably, flexibly, and coherently to unexpected environmental changes and modifications in the robot team that may occur due to mechanical failure, the learning of new skills, or the addition or removal of robots from the team by human intervention. The feasibility of this architecture is demonstrated in an implementation on a team of mobile robots performing a laboratory version of hazardous waste cleanup.

  15. Fault-tolerant error correction with the gauge color code

    Science.gov (United States)

    Brown, Benjamin J.; Nickerson, Naomi H.; Browne, Dan E.

    2016-07-01

    The constituent parts of a quantum computer are inherently vulnerable to errors. To this end, we have developed quantum error-correcting codes to protect quantum information from noise. However, discovering codes that are capable of a universal set of computational operations with the minimal cost in quantum resources remains an important and ongoing challenge. One proposal of significant recent interest is the gauge color code. Notably, this code may offer a reduced resource cost over other well-studied fault-tolerant architectures by using a new method, known as gauge fixing, for performing the non-Clifford operations that are essential for universal quantum computation. Here we examine the gauge color code when it is subject to noise. Specifically, we make use of single-shot error correction to develop a simple decoding algorithm for the gauge color code, and we numerically analyse its performance. Remarkably, we find threshold error rates comparable to those of other leading proposals. Our results thus provide the first steps of a comparative study between the gauge color code and other promising computational architectures.

  16. ALLIANCE: An architecture for fault tolerant multi-robot cooperation

    International Nuclear Information System (INIS)

    ALLIANCE is a software architecture that facilitates the fault tolerant cooperative control of teams of heterogeneous mobile robots performing missions composed of loosely coupled, largely independent subtasks. ALLIANCE allows teams of robots, each of which possesses a variety of high-level functions that it can perform during a mission, to individually select appropriate actions throughout the mission based on the requirements of the mission, the activities of other robots, the current environmental conditions, and the robot's own internal states. ALLIANCE is a fully distributed, behavior-based architecture that incorporates the use of mathematically modeled motivations (such as impatience and acquiescence) within each robot to achieve adaptive action selection. Since cooperative robotic teams usually work in dynamic and unpredictable environments, this software architecture allows the robot team members to respond robustly, reliably, flexibly, and coherently to unexpected environmental changes and modifications in the robot team that may occur due to mechanical failure, the learning of new skills, or the addition or removal of robots from the team by human intervention. The feasibility of this architecture is demonstrated in an implementation on a team of mobile robots performing a laboratory version of hazardous waste cleanup

  17. A PROBABILISTIC CHARACTERIZATION OF A FAULT-TOLERANT GOSSIPING ALGORITHM

    Institute of Scientific and Technical Information of China (English)

    Xiaohu LI; Paul PARKER; Shouhuai XU

    2009-01-01

    Gossiping is a popular technique for probabilistic reliable multicast (or broadcast). However,it is often difficult to understand the behavior of gossiping algorithms in an analytic fashion. Indeed,existing analyses of gossip algorithms are either based on simulation or based on ideas borrowed from epidemic models while inheriting some features that do not seem to be appropriate for the setting of gossiping. On one hand, in epidemic spreading, an infected node typically intends to spread the infection an unbounded number of times (or rounds); whereas in gossiping, an infected node (i.e., a node having received the message in question) may prefer to gossip the message a bounded number of times. On the other hand, the often assumed homogeneity in epidemic spreading models (especially that every node has equal contact to everyone else in the population) has been silently inherited in the gossiping literature, meaning that an expensive membership protocol is often needed for maintaining nodes' views. Motivated by these observations, the authors present a characterization of a popular class of fault-tolerant gossip schemes (known as "push-based gossiping") based on a novel probabilistic model, while taking the afore-mentioned factors into consideration.

  18. Probabilistic analysis on fault tolerance of 3-Dimensional mesh networks

    Institute of Scientific and Technical Information of China (English)

    王高才; 陈建二; 王国军; 陈松乔

    2003-01-01

    The probability model is used to analyze the fault tolerance of mesh. To simplify its analysis, it is as-sumed that the failure probability of each node is independent. A 3-D mesh is partitioned into smaller submeshes,and then the probability with which each submesh satisfies the defined condition is computed. If each submesh satis-fies the condition, then the whole mesh is connected. Consequently, the probability that a 3-D mesh is connected iscomputed assuming each node has a failure probability. Mathematical methods are used to derive a relationship be-tween network node failure probability and network connectivity probability. The calculated results show that the 3-D mesh networks can remain connected with very high probability in practice. It is formally proved that when thenetwork node failure probability is boutded by 0.45 %, the 3-D mesh networks of more than three hundred thousandnodes remain connected with probability larger than 99 %. The theoretical results show that the method is a power-ful technique to calculate the lower bound of the connectivity probability of mesh networks.

  19. Fault-tolerant quantum blind signature protocols against collective noise

    Science.gov (United States)

    Zhang, Ming-Hui; Li, Hui-Fang

    2016-07-01

    This work proposes two fault-tolerant quantum blind signature protocols based on the entanglement swapping of logical Bell states, which are robust against two kinds of collective noises: the collective-dephasing noise and the collective-rotation noise, respectively. Both of the quantum blind signature protocols are constructed from four-qubit decoherence-free (DF) states, i.e., logical Bell qubits. The initial message is encoded on the logical Bell qubits with logical unitary operations, which will not destroy the anti-noise trait of the logical Bell qubits. Based on the fundamental property of quantum entanglement swapping, the receiver simply performs two Bell-state measurements (rather than four-qubit joint measurements) on the logical Bell qubits to verify the signature, which makes the protocols more convenient in a practical application. Different from the existing quantum signature protocols, our protocols can offer the high fidelity of quantum communication with the employment of logical qubits. Moreover, we hereinafter prove the security of the protocols against some individual eavesdropping attacks, and we show that our protocols have the characteristics of unforgeability, undeniability and blindness.

  20. Proposal of fault-tolerant tomographic image reconstruction

    CERN Document Server

    Kudo, Hiroyuki; Yamazaki, Fukashi; Nemoto, Takuya

    2016-01-01

    This paper deals with tomographic image reconstruction under the situation where some of projection data bins are contaminated with abnormal data. Such situations occur in various instances of tomography. We propose a new reconstruction algorithm called the Fault-Tolerant reconstruction outlined as follows. The least-squares (L2-norm) error function ||Ax-b||_2^2 used in ordinary iterative reconstructions is sensitive to the existence of abnormal data. The proposed algorithm utilizes the L1-norm error function ||Ax-b||_1^1 instead of the L2-norm, and we develop a row-action-type iterative algorithm using the proximal splitting framework in convex optimization fields. We also propose an improved version of the L1-norm reconstruction called the L1-TV reconstruction, in which a weak Total Variation (TV) penalty is added to the cost function. Simulation results demonstrate that reconstructed images with the L2-norm were severely damaged by the effect of abnormal bins, whereas images with the L1-norm and L1-TV reco...

  1. The Research and Implementation of Fault-Tolerance Mechanism of Distributed Object Based on CORBA%基于CORBA的分布对象容错机制研究与实现

    Institute of Scientific and Technical Information of China (English)

    李琪林; 陈宇; 周明天

    2002-01-01

    Presently, distributed object technology such as CORBA has increasingly become mature. More and moredistributed application systems are implemented using the standard services and protocols provided by CORBA. Thenew-generation distributed systems such as real time systems, online paying systems and stock exchange systems de-mand assurance of dependability. Fault tolerance is a main way of assurance of system reliability. Thereby, it re-quires low-level CORBA infrastructure to provide fault-tolerance mechanism to ensure dependability and availability.This paper firstly discusses implementation strategy and system model of fault-tolerance CORBA object systems. Sec-ondly, it describes main challenges and solutions during the design of fault-tolerance CORBA systems. Thirdly it in-troduces fault-tolerance CORBA prototype system-TBAFTS on top of a CORBA-compliant object middleware, Tong-Broker developed by us independently. Finally we give our conclusion.

  2. Fault Tolerant Architecture For A Fly-By-Light Flight Control Computer

    Science.gov (United States)

    Thompson, Kevin; Stipanovich, John; Smith, Brian; Reddy, Mahesh C.

    1990-02-01

    The next generation of flight control computers will utilize fiber optic technology to produce a fly-by-light flight control system. Optical transducers and optical fibers will take the place of electrical position transducers and wires, torsion bars, bell cranks, and cables. Applications for this fly-by-light technology include space launch vehicles, upperstages, space-craft, and commercial/military aircraft. Optical fibers are lighter than mechanical transmission media and unlike conven-tional wire transmissions are not susceptible to electromagnetic interference (EMI) and high energy emission sources. This paper will give an overview of a fault tolerant In-Line Monitored optical flight control system being developed at Boeing Aerospace & Electronics in Seattle, Washington. This system uses passive transducers with fiber optic interconnections which hold promises to virtually eliminate EMI threats to flight control system performance and flight safety and also provide significant weight savings. The main emphasis of this paper will be the In-Line Monitored architecture of the optical transducer system required for use in a fault tolerant flight control system.

  3. Fault Diagnosis and Fault-Tolerant Control of Wind Turbines via a Discrete Time Controller with a Disturbance Compensator

    Directory of Open Access Journals (Sweden)

    Yolanda Vidal

    2015-05-01

    Full Text Available This paper develops a fault diagnosis (FD and fault-tolerant control (FTC of pitch actuators in wind turbines. This is accomplished by combining a disturbance compensator with a controller, both of which are formulated in the discrete time domain. The disturbance compensator has a dual purpose: to estimate the actuator fault (which is used by the FD algorithm and to design the discrete time controller to obtain an FTC. That is, the pitch actuator faults are estimated, and then, the pitch control laws are appropriately modified to achieve an FTC with a comparable behavior to the fault-free case. The performance of the FD and FTC schemes is tested in simulations with the aero-elastic code FAST.

  4. Physiological hemostasis based intelligent integrated cooperative controller for precise fault-tolerant control of redundant parallel manipulator

    Science.gov (United States)

    Hao, Kuangrong; Guo, Chongbin; Ding, Yongsheng

    2014-10-01

    This paper focuses on precise fault-tolerant control for actual redundant parallel manipulator. Based on kinematic redundancy, some unnoticed influences such as mechanical clearance have been considered to design a more precise and intelligent fault-tolerant plan for actual plants. According to regulation principles in human hemostasis system, a bio-inspired intelligent integrated cooperative controller (BIICC) is developed including system structure, algorithm and step in parameter tuning. The proposed BIICC optimises partial error signal and improves control performance in each sub-channel. Moreover, the new controller transfers and disposes cooperative control signals among different sub-channels to achieve an intelligent integrated fault-tolerant system. The proposed BIICC is applied to an actual 2-DOF (degrees of freedom) redundant parallel manipulator where the feasibility of the new controller is demonstrated. The BIICC is beneficial to control precision and fault-tolerant capability of redundant plant. The improvements are more obvious in cases where extra actuators of redundant manipulator are broken.

  5. Velocity-free fault-tolerant control allocation for flexible spacecraft with redundant thrusters

    Science.gov (United States)

    Hu, Qinglei; Li, Bo; Wang, Danwei; Poh, Eng Kee

    2015-04-01

    This paper proposes a novel velocity-free nonlinear proportional-integral (PI) control allocation scheme for fault-tolerant attitude control of flexible spacecraft under thruster redundancy. More specifically, the nonlinear PI controller for attitude stabilisation without using body angular velocity measurements is first designed as a virtual control of the control allocator to produce the three-axis moments, and can ultimately guarantee uniform boundedness of the closed-loop system in the presence of external disturbances and possible faults. The associated stability proof is constructive and accomplished by the development of passivity filter formulations together with the choice of a Lyapunov function containing mixed terms involving the various states. Then, a robust least-squares-based control allocation is employed to deal with the problem of distributing the three-axis moments over the available thrusters under redundancy, in which the focus of this control allocation is to find the optimal control vector of the actuator by minimising the worst-case residual, under the condition of thruster faults and control constraints like saturation. Simulation results using the orbiting flexible spacecraft model show good performance under external disturbances and even in different thruster fault scenarios, which validates the effectiveness and feasibility of the proposed scheme.

  6. Robust Fault-Tolerant Control for Satellite Attitude Stabilization Based on Active Disturbance Rejection Approach with Artificial Bee Colony Algorithm

    Directory of Open Access Journals (Sweden)

    Fei Song

    2014-01-01

    Full Text Available This paper proposed a robust fault-tolerant control algorithm for satellite stabilization based on active disturbance rejection approach with artificial bee colony algorithm. The actuating mechanism of attitude control system consists of three working reaction flywheels and one spare reaction flywheel. The speed measurement of reaction flywheel is adopted for fault detection. If any reaction flywheel fault is detected, the corresponding fault flywheel is isolated and the spare reaction flywheel is activated to counteract the fault effect and ensure that the satellite is working safely and reliably. The active disturbance rejection approach is employed to design the controller, which handles input information with tracking differentiator, estimates system uncertainties with extended state observer, and generates control variables by state feedback and compensation. The designed active disturbance rejection controller is robust to both internal dynamics and external disturbances. The bandwidth parameter of extended state observer is optimized by the artificial bee colony algorithm so as to improve the performance of attitude control system. A series of simulation experiment results demonstrate the performance superiorities of the proposed robust fault-tolerant control algorithm.

  7. Distributed Fault-Tolerant Event Region Detection of Wireless Sensor Networks

    OpenAIRE

    Dyi-Rong Duh; Ssu-Pei Li; Victor W. Cheng

    2013-01-01

    This work provides a distributed fault-tolerant event region detection algorithm for wireless sensor networks. The proposed algorithm can identify faulty and fault-free sensors and ignore the abnormal readings to avoid false alarm. Moreover, every event region can also be detected and identified. Simulation results show that fault detection accuracy (FDA) is greater than 92%, false alarm rate (FAR) is near 0%, and event detection accuracy (EDA) is greater than 99% under uniform distribution. ...

  8. Control strategy with minimal controller reconfiguration of fault tolerant polyphase PMSMdrives under open circuit fault of one phase

    OpenAIRE

    Baudart, François; Dehez, Bruno; Labrique, Francis; Matagne, Ernest; Telteu, Dan; Alexandre, Paul; 19th International Conference on Electrical Machines (ICEM 2010)

    2010-01-01

    Segment polyphase motors gain interest in applications requiring high performance and high reliability due to their high fault tolerance. This paper sums up the generalization of the vector control strategy of such motor and presents a method to adapt with a minimal reconfiguration the control strategy in the case of an open phase failure. Simulations results validate the method.

  9. An Adaptive Job Scheduling with efficient Fault Tolerance Strategy in Computational Grid

    Directory of Open Access Journals (Sweden)

    S. Gokuldev

    2014-08-01

    Full Text Available Grid computing is an emerging technology which has the potential to solve large scale scientific problems in an integrated heterogeneous environment. However, in the grid computing environment there are certain aspects which reduces efficiency of the system. Scheduling the jobs to the best suited resources, achieving the load balancing and fault tolerance are the key aspects to improve the efficiency and to exploit the capabilities of emergent computational systems. Because of dynamic and distributed nature of the grid, the traditional methodologies of scheduling are inefficient for the effective utilization of the available resources. In this paper, an efficient adaptive job scheduling algorithm is proposed to improve the efficiency of the grid system for a large number of tasks. Moreover, the proposed adaptive job scheduling in addition to the fault tolerance strategy with check pointing approach shows the improvement in performance of the overall computation time even in worst scenario under the heterogeneous grid environment. The simulation results illustrates that the proposed strategy effectively schedules the grid jobs with more than 10% increase in overall performance thus resulting in minimization of overall execution time.

  10. An Evaluation of Fault Tolerant Wind Turbine Control Schemes applied to a Benchmark Model

    DEFF Research Database (Denmark)

    Odgaard, Peter Fogh; Stoustrup, Jakob

    2014-01-01

    Reliability and availability of modern wind turbines increases in importance as the ratio in the world's power supply increases. This is important in order to increase the energy generated per unit and their lowering cost of energy and as well to ensure availability of generated power, which helps...... keeping the power grids stable. Advanced Fault Tolerant Control is one of the potential tools to increase reliability of modern wind turbines. A benchmark model for wind turbine fault detection and isolation and fault tolerant control has previously been proposed, and based on this benchmark...

  11. High available and fault tolerant mobile communications infrastructure

    DEFF Research Database (Denmark)

    Beiroumi, Mohammad Zib

    2006-01-01

    infrastructure. The method enables the faulty applications in the infrastructure to quickly and effectively resume their services to their mobile clients with no or minimal loss of work after failure. In our approach, we do not assume a specific fault behavior for example failstop or transient behavior...... as it is the case for many recovery techniques. In addition, the method does not require any modification to mobile clients. The Communicating Extended Finite State Machine (CEFSM) is used to model the behavior of the infrastructure applications. The model based recovery scheme is integrated in the application...... and demonstrate the effectiveness of our method, we developed as a case study an experimental testbed for the TETRA (TErrestrial Trunked Radio) packet data network. The testbed works as a distributed system and can run various communication scenarios between the fixed network infrastructure and its mobile users...

  12. Performance analysis of a dependable scheduling strategy based on a fault-tolerant grid model

    Institute of Scientific and Technical Information of China (English)

    WANG Yuanzhuo; LIN Chuang; YANG Yang; SHAN Zhiguang

    2007-01-01

    The grid provides an integrated computer platform composed of differentiated and distributed systems.These resources are dynamic and heterogeneous.In this paper,a novel fault-tolerant grid-scheduling model is pre sented based on Stochastic Petri Nets (SPN) to assure the heterogeneity and dynamism of the grid system.Also,a new grid-scheduling strategy,the dependable strategy for the shortest expected accomplishing time (DSEAT),is put forward,in which the dependability factor is introduced in the task-dispatching strategy.In the end,the performance of the scheduling strategy based on the fault-tolerant gridscheduling model is analyzed by an software package,named SPNP.The numerical results show that dynamic resources will increase the response time for all classes of tasks in differing degrees.Compared with shortest expected accomplishing time (SEAT) strategy,the DSEAT strategy can reduce the negative effects of dynamic and autonomic resources to some extent so as to guarantee a high quality of service (QoS).

  13. Clustering and fault tolerance for target tracking using wireless sensor networks

    International Nuclear Information System (INIS)

    Over the last few years, the deployment of WSNs (Wireless Sensor Networks) has been fostered in diverse applications. WSN has great potential for a variety of domains ranging from scientific experiments to commercial applications. Due to the deployment of WSNs in dynamic and unpredictable environments. They have potential to cope with variety of faults. This paper proposes an energy-aware fault-tolerant clustering protocol for target tracking applications termed as the FITf (Fault Tolerant Target Tracking) protocol The identification of RNs (Redundant Nodes) makes SN (Sensor Node) fault tolerance plausible and the clustering endorsed recovery of sensors supervised by a faulty CH (Cluster Head). The FfTT protocol intends two steps of reducing energy consumption: first, by identifying RNs in the network; secondly, by restricting the numbers of SNs sending data to the CH. Simulations validate the scalability and low power consumption of the FITf protocol in comparison with LEACH protocol. (author)

  14. Clustering and Fault Tolerance for Target Tracking using Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Sania Bhatti

    2012-10-01

    Full Text Available Over the last few years, the deployment of WSNs (Wireless Sensor Networks has been fostered in diverse applications. WSN has great potential for a variety of domains ranging from scientific experiments to commercial applications. Due to the deployment of WSNs in dynamic and unpredictable environments. They have potential to cope with variety of faults. This paper proposes an energy-aware fault-tolerant clustering protocol for target tracking applications termed as the FTTT (Fault Tolerant Target Tracking protocol. The identification of RNs (Redundant Nodes makes SN (Sensor Node fault tolerance plausible and the clustering endorsed recovery of sensors supervised by a faulty CH (Cluster Head. The FTTT protocol intends two steps of reducing energy consumption: first, by identifying RNs in the network; secondly, by restricting the numbers of SNs sending data to the CH. Simulations validate the scalability and low power consumption of the FTTT protocol in comparison with LEACH protocol.

  15. Design of Parity Preserving Logic Based Fault Tolerant Reversible Arithmetic Logic Unit

    Directory of Open Access Journals (Sweden)

    Rakshith Saligram

    2013-07-01

    Full Text Available Reversible Logic is gaining significant consideration as the potential logic design style for implementationin modern nanotechnology and quantum computing with minimal impact on physical entropy .FaultTolerant reversible logic is one class of reversible logic that maintain the parity of the input and theoutputs. Significant contributions have been made in the literature towards the design of fault tolerantreversible logic gate structures and arithmetic units, however, there are not many efforts directed towardsthe design of fault tolerant reversible ALUs. Arithmetic Logic Unit (ALU is the prime performing unit inany computing device and it has to be made fault tolerant. In this paper we aim to design one such faulttolerant reversible ALU that is constructed using parity preserving reversible logic gates. The designedALU can generate up to seven Arithmetic operations and four logical operations.

  16. Fault-Tolerant Vision for Vehicle Guidance in Agriculture

    DEFF Research Database (Denmark)

    Blas, Morten Rufus

    The emergence of widely available vision technologies is enabling for a wide range of automation tasks in industry and other areas. Agricultural vehicle guidance systems have benefitted from advances in 3D vision based on stereo camera technology. By automatically guiding vehicles along crops...... the field that is seen by the stereo camera, it is possible to support the guidance system by storing salient information about the environment. By tracking the motion of the vehicle, vision output can be fused over time to create more reliable and robust estimates of crop location. This thesis approaches...... and other field structures the operator’s stress levels can be reduced. High precision steering in sensitive crops can also be maintained for longer periods of time as the driver is less tired. Safety and availabilitymust be inherent in such systems in order to get widespread market acceptance. To tolerate...

  17. Robot-borne fault tolerant calculators for nuclear use

    International Nuclear Information System (INIS)

    The use of robots has become a necessity in civil nuclear industry. Electronic systems of such robots must tolerate cumulative ionizing radiation dose effects. Today's objective is to reach a 3 kGy dose resistance. Difficulties and costs involved during on-site maintenance imply to warrant at least one functioning mode in the case of system failure. To improve the behaviour of robot-borne systems, the CEA Department for Nuclear Engineering Studies (DEIN) has developed a method for the selection of industrial electronic components and has built computer architectures which allows to break free from some cumulative dose sensitive parameters. This paper presents the MICADO and CADMOS architectures developed at the DEIN. (J.S.). 15 refs., 5 figs

  18. Declarative Specification of Fault Tolerant Auction Protocols: The English Auction Case Study

    DEFF Research Database (Denmark)

    Dragoni, Nicola; Gaspari, Mauro

    2012-01-01

    and shared allowing agents to dynamically engage well‐known and trusted negotiation protocols. To cope with real‐world applications, these rules should also specify fault tolerant patterns of interaction, enabling negotiating agents to interact with each other tolerating failures, for instance terminating...... an auction process even if some bidding agents dynamically crash. In this paper, we propose an approach to specify fault tolerant auction protocols in open and dynamic environments by means of communication rules dealing with crash failures of agents. We illustrate these concepts considering a case study...

  19. Adaptive Vibration Control System for MR Damper Faults

    Directory of Open Access Journals (Sweden)

    Juan C. Tudón-Martínez

    2015-01-01

    Full Text Available Several methods have been proposed to estimate the force of a semiactive damper, particularly of a magnetorheological damper because of its importance in automotive and civil engineering. Usually, all models have been proposed assuming experimental data in nominal operating conditions and some of them are estimated for control purposes. Because dampers are prone to fail, fault estimation is useful to design adaptive vibration controllers to accommodate the malfunction in the suspension system. This paper deals with the diagnosis and estimation of faults in an automotive magnetorheological damper. A robust LPV observer is proposed to estimate the lack of force caused by a damper leakage in a vehicle corner. Once the faulty damper is isolated in the vehicle and the fault is estimated, an Adaptive Vibration Control System is proposed to reduce the fault effect using compensation forces from the remaining healthy dampers. To fulfill the semiactive damper constraints in the fault adaptation, an LPV controller is designed for vehicle comfort and road holding. Simulation results show that the fault observer has good performance with robustness to noise and road disturbances and the proposed AVCS improves the comfort up to 24% with respect to a controlled suspension without fault tolerance features.

  20. A fault-tolerant addressable spin qubit in a natural silicon quantum dot.

    Science.gov (United States)

    Takeda, Kenta; Kamioka, Jun; Otsuka, Tomohiro; Yoneda, Jun; Nakajima, Takashi; Delbecq, Matthieu R; Amaha, Shinichi; Allison, Giles; Kodera, Tetsuo; Oda, Shunri; Tarucha, Seigo

    2016-08-01

    Fault-tolerant quantum computing requires high-fidelity qubits. This has been achieved in various solid-state systems, including isotopically purified silicon, but is yet to be accomplished in industry-standard natural (unpurified) silicon, mainly as a result of the dephasing caused by residual nuclear spins. This high fidelity can be achieved by speeding up the qubit operation and/or prolonging the dephasing time, that is, increasing the Rabi oscillation quality factor Q (the Rabi oscillation decay time divided by the π rotation time). In isotopically purified silicon quantum dots, only the second approach has been used, leaving the qubit operation slow. We apply the first approach to demonstrate an addressable fault-tolerant qubit using a natural silicon double quantum dot with a micromagnet that is optimally designed for fast spin control. This optimized design allows access to Rabi frequencies up to 35 MHz, which is two orders of magnitude greater than that achieved in previous studies. We find the optimum Q = 140 in such high-frequency range at a Rabi frequency of 10 MHz. This leads to a qubit fidelity of 99.6% measured via randomized benchmarking, which is the highest reported for natural silicon qubits and comparable to that obtained in isotopically purified silicon quantum dot-based qubits. This result can inspire contributions to quantum computing from industrial communities. PMID:27536725

  1. Rollback recovery with low overhead for fault tolerance in mobile ad hoc networks

    Directory of Open Access Journals (Sweden)

    Parmeet Kaur Jaggi

    2015-10-01

    Full Text Available Mobile ad hoc networks (MANETs have significantly enhanced the wireless networks by eliminating the need for any fixed infrastructure. Hence, these are increasingly being used for expanding the computing capacity of existing networks or for implementation of autonomous mobile computing Grids. However, the fragile nature of MANETs makes the constituent nodes susceptible to failures and the computing potential of these networks can be utilized only if they are fault tolerant. The technique of checkpointing based rollback recovery has been used effectively for fault tolerance in static and cellular mobile systems; yet, the implementation of existing protocols for MANETs is not straightforward. The paper presents a novel rollback recovery protocol for handling the failures of mobile nodes in a MANET using checkpointing and sender based message logging. The proposed protocol utilizes the routing protocol existing in the network for implementing a low overhead recovery mechanism. The presented recovery procedure at a node is completely domino-free and asynchronous. The protocol is resilient to the dynamic characteristics of the MANET; allowing a distributed application to be executed independently without access to any wired Grid or cellular network access points. We also present an algorithm to record a consistent global snapshot of the MANET.

  2. A fault-tolerant addressable spin qubit in a natural silicon quantum dot

    Science.gov (United States)

    Takeda, Kenta; Kamioka, Jun; Otsuka, Tomohiro; Yoneda, Jun; Nakajima, Takashi; Delbecq, Matthieu R.; Amaha, Shinichi; Allison, Giles; Kodera, Tetsuo; Oda, Shunri; Tarucha, Seigo

    2016-01-01

    Fault-tolerant quantum computing requires high-fidelity qubits. This has been achieved in various solid-state systems, including isotopically purified silicon, but is yet to be accomplished in industry-standard natural (unpurified) silicon, mainly as a result of the dephasing caused by residual nuclear spins. This high fidelity can be achieved by speeding up the qubit operation and/or prolonging the dephasing time, that is, increasing the Rabi oscillation quality factor Q (the Rabi oscillation decay time divided by the π rotation time). In isotopically purified silicon quantum dots, only the second approach has been used, leaving the qubit operation slow. We apply the first approach to demonstrate an addressable fault-tolerant qubit using a natural silicon double quantum dot with a micromagnet that is optimally designed for fast spin control. This optimized design allows access to Rabi frequencies up to 35 MHz, which is two orders of magnitude greater than that achieved in previous studies. We find the optimum Q = 140 in such high-frequency range at a Rabi frequency of 10 MHz. This leads to a qubit fidelity of 99.6% measured via randomized benchmarking, which is the highest reported for natural silicon qubits and comparable to that obtained in isotopically purified silicon quantum dot–based qubits. This result can inspire contributions to quantum computing from industrial communities. PMID:27536725

  3. Software fault detection and recovery in critical real-time systems: An approach based on loose coupling

    International Nuclear Information System (INIS)

    Highlights: •We analyze fault tolerance in mission-critical real-time systems. •Decoupled architectural model can be used to implement fault tolerance. •Prototype implementation for remote handling control system and service manager. •Recovery from transient faults by restarting services. -- Abstract: Remote handling (RH) systems are used to inspect, make changes to, and maintain components in the ITER machine and as such are an example of mission-critical system. Failure in a critical system may cause damage, significant financial losses and loss of experiment runtime, making dependability one of their most important properties. However, even if the software for RH control systems has been developed using best practices, the system might still fail due to undetected faults (bugs), hardware failures, etc. Critical systems therefore need capability to tolerate faults and resume operation after their occurrence. However, design of effective fault detection and recovery mechanisms poses a challenge due to timeliness requirements, growth in scale, and complex interactions. In this paper we evaluate effectiveness of service-oriented architectural approach to fault tolerance in mission-critical real-time systems. We use a prototype implementation for service management with an experimental RH control system and industrial manipulator. The fault tolerance is based on using the high level of decoupling between services to recover from transient faults by service restarts. In case the recovery process is not successful, the system can still be used if the fault was not in a critical software module

  4. Combining Artificial Intelligence and Advanced Techniques in Fault-Tolerant Control

    Directory of Open Access Journals (Sweden)

    A. Vargas-Martínez

    2011-08-01

    Full Text Available We present the integration of artificial intelligence, robust, nonlinear and model reference adaptive control (MRACmethods for fault-tolerant control (FTC. We combine MRAC schemes with classical PID controllers, artificial neuralnetworks (ANNs, genetic algorithms (GAs, H∞ controls and sliding mode controls. Six different schemas areproposed: the first one is an MRAC with an artificial neural network and a PID controller whose parameters weretuned by a GA using Pattern Search Optimization. The second scheme is an MRAC controller with an H∞ control(H∞. The third scheme is an MRAC controller with a sliding mode controller (SMC. The fourth scheme is an MRACcontroller with an ANN. The fifth scheme is an MRAC controller with a PID controller optimized by a GA. Finally, thelast scheme is an MRAC classical control system. The objective of this research is to generate more powerful FTCmethods and compare the performance of above schemes under different fault conditions in sensors and actuators.An industrial heat exchanger process was the test bed for these approaches. Simulation results showed that the useof Pattern Search Optimization and ANNs improved the performance of the FTC scheme because it makes the controlsystem more robust against sensor and actuator faults.

  5. Automatic Fault-Tolerance Support in Resource Management System Based on Job Checkpoint/Restart%资源管理系统中基于作业检查点的自动容错

    Institute of Scientific and Technical Information of China (English)

    曹宏嘉; 卢宇彤; 谢旻

    2009-01-01

    An automatic fault-tolerance method based on job checkpoint/restart in resource management systems is pro-posed The key technologies are presented, including the separation of job checkpoint and task checkpoint, management of checkpoint image files, and automatic job restart.Automatic job checkpoint/restart with BLCR is implemented in SLURM and the challenges are discussed. Analysis and experiments show that the checkpoint and restart works correctly, and the time to complete large-scale jobs is reduced effectively.%本文提出了在资源管理系统中基于作业检查点实现自动容错支持,深入分析了作业与任务检查点分离、映像文件管理、自动恢复执行等关键技术.基于BLCR在SLURM中实现了作业的自动检查点/恢复,详细介绍了实现中的关键技术难题.分析与测试表明,检查点与恢复执行功能正确,并能有效缩短大规模作业成功运行所需的时间.

  6. Sensor-driven, fault-tolerant control of a maintenance robot

    International Nuclear Information System (INIS)

    A robot system has been designed to do routine maintenance tasks on the Sandia Pulsed Reactor (SPR). The use of this Remote Maintenance Robot (RMR) is expected to significantly reduce the occupational radiation exposure of the reactor operators. Reactor safety was a key issue in the design of the robot maintenance system. Using sensors to detect error conditions and intelligent control to recover from the errors, the RMR is capable of responding to error conditions without creating a hazard. This paper describes the design and implementation of a sensor-driven, fault-tolerant control for the RMR. Recovery from errors is not automatic; it does rely on operator assistance. However, a key feature of the error recovery procedure is that the operator is allowed to reenter the programmed operation after the error has been corrected. The recovery procedure guarantees that the moving components of the system will not collide with the reactor during recovery

  7. Soft-Fault Detection Technologies Developed for Electrical Power Systems

    Science.gov (United States)

    Button, Robert M.

    2004-01-01

    The NASA Glenn Research Center, partner universities, and defense contractors are working to develop intelligent power management and distribution (PMAD) technologies for future spacecraft and launch vehicles. The goals are to provide higher performance (efficiency, transient response, and stability), higher fault tolerance, and higher reliability through the application of digital control and communication technologies. It is also expected that these technologies will eventually reduce the design, development, manufacturing, and integration costs for large, electrical power systems for space vehicles. The main focus of this research has been to incorporate digital control, communications, and intelligent algorithms into power electronic devices such as direct-current to direct-current (dc-dc) converters and protective switchgear. These technologies, in turn, will enable revolutionary changes in the way electrical power systems are designed, developed, configured, and integrated in aerospace vehicles and satellites. Initial successes in integrating modern, digital controllers have proven that transient response performance can be improved using advanced nonlinear control algorithms. One technology being developed includes the detection of "soft faults," those not typically covered by current systems in use today. Soft faults include arcing faults, corona discharge faults, and undetected leakage currents. Using digital control and advanced signal analysis algorithms, we have shown that it is possible to reliably detect arcing faults in high-voltage dc power distribution systems (see the preceding photograph). Another research effort has shown that low-level leakage faults and cable degradation can be detected by analyzing power system parameters over time. This additional fault detection capability will result in higher reliability for long-lived power systems such as reusable launch vehicles and space exploration missions.

  8. A fault tolerant model for multi-sensor measurement

    Directory of Open Access Journals (Sweden)

    Li Liang

    2015-06-01

    Full Text Available Multi-sensor systems are very powerful in the complex environments. The cointegration theory and the vector error correction model, the statistic methods which widely applied in economic analysis, are utilized to create a fitting model for homogeneous sensors measurements. An algorithm is applied to implement the model for error correction, in which the signal of any sensor can be estimated from those of others. The model divides a signal series into two parts, the training part and the estimated part. By comparing the estimated part with the actual one, the proposed method can identify a sensor with possible faults and repair its signal. With a small amount of training data, the right parameters for the model in real time could be found by the algorithm. When applied in data analysis for aero engine testing, the model works well. Therefore, it is not only an effective method to detect any sensor failure or abnormality, but also a useful approach to correct possible errors.

  9. Active fault detection in MIMO systems

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik; Poulsen, Niels Kjølstad

    2014-01-01

    The focus in this paper is on active fault detection (AFD) for MIMO systems with parametric faults. The problem of design of auxiliary inputs with respect to detection of parametric faults is investigated. An analysis of the design of auxiliary inputs is given based on analytic transfer functions...... from auxiliary input to residual outputs. The analysis is based on a singular value decomposition of these transfer functions Based on this analysis, it is possible to design auxiliary input as well as design of the associated residual vector with respect to every single parametric fault in the system...

  10. Fault system polarity: A matter of chance?

    Science.gov (United States)

    Schöpfer, Martin; Childs, Conrad; Manzocchi, Tom; Walsh, John; Nicol, Andy; Grasemann, Bernhard

    2015-04-01

    Many normal fault systems and, on a smaller scale, fracture boudinage exhibit asymmetry so that one fault dip direction dominates. The fraction of throw (or heave) accommodated by faults with the same dip direction in relation to the total fault system throw (or heave) is a quantitative measure of fault system asymmetry and termed 'polarity'. It is a common belief that the formation of domino and shear band boudinage with a monoclinic symmetry requires a component of layer parallel shearing, whereas torn boudins reflect coaxial flow. Moreover, domains of parallel faults are frequently used to infer the presence of a common décollement. Here we show, using Distinct Element Method (DEM) models in which rock is represented by an assemblage of bonded circular particles, that asymmetric fault systems can emerge under symmetric boundary conditions. The pre-requisite for the development of domains of parallel faults is however that the medium surrounding the brittle layer has a very low strength. We demonstrate that, if the 'competence' contrast between the brittle layer and the surrounding material ('jacket', or 'matrix') is high, the fault dip directions and hence fault system polarity can be explained using a random process. The results imply that domains of parallel faults are, for the conditions and properties used in our models, in fact a matter of chance. Our models suggest that domino and shear band boudinage can be an unreliable shear-sense indicator. Moreover, the presence of a décollement should not be inferred on the basis of a domain of parallel faults only.

  11. IMPROVING FAULT TOLERANT RESOURCE OPTIMIZED AWARE JOB SCHEDULING FOR GRID COMPUTING

    Directory of Open Access Journals (Sweden)

    K. Nirmala Devi

    2014-01-01

    Full Text Available Workflow brokers of existing Grid Scheduling Systems are lack of cooperation mechanism which causes inefficient schedules of application distributed resources and it also worsens the utilization of various resources including network bandwidth and computational cycles. Furthermore considering the literature, all of these existing brokering systems primarily evolved around models of centralized hierarchical or client/server. In such models, vital responsibility such as resource discovery is delegated to the centralized server machines, thus they are associated with well-known disadvantages regarding single point of failure, scalability and network congestion at links that are leading to the server. In order to overcome these issues, we implement a new approach for decentralized cooperative workflow scheduling in a dynamically distributed resource sharing environment of Grids. The various actors in the system namely the users who belong to multiple control domains, workflow brokers and resources work together enabling a single cooperative resource sharing environment. But this approach ignored the fact that each grid site may have its own fault-tolerance strategy because each site is itself an autonomous domain. For instance, if a grid site handles the job check-pointing mechanism, each computation node must have the ability of periodical transmission of transient state of the job execution by computational node to the server. When there is a failure of job, it will migrate to another computational node and resume from the last stored checkpoint. A Glow worm Swarm Optimization (GSO for job scheduling is used to address the issue of heterogeneity in fault-tolerance of computational grid but Weighted GSO that overcomes the position update imperfections of general GSO in a more efficient manner shown during comparison analysis. This system supports four kinds of fault-tolerance mechanisms, including the job migration, job retry, check-pointing and

  12. Design of Fault-Tolerant and Dynamically-Reconfigurable Microfluidic Biochips

    CERN Document Server

    Su, Fei

    2011-01-01

    Microfluidics-based biochips are soon expected to revolutionize clinical diagnosis, DNA sequencing, and other laboratory procedures involving molecular biology. Most microfluidic biochips are based on the principle of continuous fluid flow and they rely on permanently-etched microchannels, micropumps, and microvalves. We focus here on the automated design of "digital" droplet-based microfluidic biochips. In contrast to continuous-flow systems, digital microfluidics offers dynamic reconfigurability; groups of cells in a microfluidics array can be reconfigured to change their functionality during the concurrent execution of a set of bioassays. We present a simulated annealing-based technique for module placement in such biochips. The placement procedure not only addresses chip area, but it also considers fault tolerance, which allows a microfluidic module to be relocated elsewhere in the system when a single cell is detected to be faulty. Simulation results are presented for a case study involving the polymeras...

  13. Fault-Tolerant Technique in the Cluster Computation of the Digital Watershed Model

    Institute of Scientific and Technical Information of China (English)

    SHANG Yizi; WU Baosheng; LI Tiejian; FANG Shenguang

    2007-01-01

    This paper describes a parallel computing platform using the existing facilities for the digital watershed model. In this paper, distributed multi-layered structure is applied to the computer cluster system, and the MPI-2 is adopted as a mature parallel programming standard. An agent is introduced which makes it possible to be multi-level fault-tolerant in software development. The communication protocol based on checkpointing and rollback recovery mechanism can realize the transaction reprocessing. Compared with conventional platform, the new system is able to make better use of the computing resource. Experimental results show the speedup ratio of the platform is almost 4 times as that of the conventional one, which demonstrates the high efficiency and good performance of the new approach.

  14. Fuzzy Logic-Based Secure and Fault Tolerant Job Scheduling in Grid

    Institute of Scientific and Technical Information of China (English)

    WANG Cheng; JIANG Congfeng; LIU Xiaohu

    2007-01-01

    The uncertainties of grid sites security are main hurdle to make the job scheduling secure, reliable and fault-tolerant. Most existing scheduling algorithms use fixed-number job replications to provide fault tolerant ability and high scheduling success rate, which consume excessive resources or can not provide sufficient fault tolerant functions when grid security conditions change. In this paper a fuzzy-logic-based self-adaptive replication scheduling (FSARS) algorithm is proposed to handle the fuzziness or uncertainties of job replication number which is highly related to trust factors behind grid sites and user jobs. Remote sens-ing-based soil moisture extraction (RSBSME) workload experiments in real grid environment are performed to evaluate the proposed approach and the results show that high scheduling success rate of up to 95% and less grid resource utilization can be achieved through FSARS. Extensive experiments show that FSARS scales well when user jobs and grid sites increase.

  15. A Fault Tolerant Congestion Aware Routing Protocol for Mobile Adhoc Networks

    Directory of Open Access Journals (Sweden)

    K. Duraiswamy

    2012-01-01

    Full Text Available Problem statement: The performance of ad hoc routing protocols will significantly degrade when there are faulty nodes in the network. Packet losses and bandwidth degradation are caused due to congestion and thus, time and energy is wasted during its recovery. The fault tolerant congestion aware routing protocol addresses these problems by exploring the network redundancy through multipath routing. Approach: In this study, it is proposed to design a fault tolerant congestion aware multi path routing protocol to reduce the route breakages and congestion losses. The AOMDV protocol is used as a base for the multipath routing. This proposed scheme enables more nodes to salvage a dropped packet. Results: Simulation results show that the proposed protocol achieves better throughput and packet delivery ratio with reduced delay, packet drop and energy. Conclusion: An effective congestion control technique proposed in this study proactively detects node level and link level congestion and performs congestion control using the fault-tolerant multiple paths.

  16. Novel Design for Quantum Dots Cellular Automata to Obtain Fault-Tolerant Majority Gate

    Directory of Open Access Journals (Sweden)

    Razieh Farazkish

    2012-01-01

    Full Text Available Quantum-dot Cellular Automata (QCA is one of the most attractive technologies for computing at nanoscale. The principle element in QCA is majority gate. In this paper, fault-tolerance properties of the majority gate is analyzed. This component is suitable for designing fault-tolerant QCA circuits. We analyze fault-tolerance properties of three-input majority gate in terms of misalignment, missing, and dislocation cells. In order to verify the functionality of the proposed component some physical proofs using kink energy (the difference in electrostatic energy between the two polarization states and computer simulations using QCA Designer tool are provided. Our results clearly demonstrate that the redundant version of the majority gate is more robust than the standard style for this gate.

  17. Implementation of the Six Channel Redundancy to achieve fault tolerance in testing of satellites

    CERN Document Server

    Aravinda, H S; Moodithaya, Ranjan

    2010-01-01

    This paper aims to implement the six channel redundancy to achieve fault tolerance in testing of satellites with acoustic spectrum. We mainly focus here on achieving fault tolerance. An immediate application is the microphone data acquisition and to do analysis at the Acoustic Test Facility (ATF) centre, National Aerospace Laboratories. It has an 1100 cubic meter reverberation chamber in which a maximum sound pressure level of 157 dB is generated. The six channel Redundancy software with fault tolerant operation is devised and developed. The data are applied to program written in C language. The program is run using the Code Composer Studio by accepting the inputs. This is tested with the TMS 320C 6727 DSP, Pro Audio Development Kit (PADK).

  18. Open-Phase Fault Tolerance Techniques of Five-Phase Dual-Rotor Permanent Magnet Synchronous Motor

    Directory of Open Access Journals (Sweden)

    Jing Zhao

    2015-11-01

    Full Text Available Multi-phase motors are gaining more attention due to the advantages of good fault tolerance capability and high power density, etc. By applying dual-rotor technology to multi-phase machines, a five-phase dual-rotor permanent magnet synchronous motor (DRPMSM is researched in this paper to further promote their torque density and fault tolerance capability. It has two rotors and two sets of stator windings, and it can adopt a series drive mode or parallel drive mode. The fault-tolerance capability of the five-phase DRPMSM is researched. All open circuit fault types and corresponding fault tolerance techniques in different drive modes are analyzed. A fault-tolerance control strategy of injecting currents containing a certain third harmonic component is proposed for five-phase DRPMSM to ensure performance after faults in the motor or drive circuit. For adjacent double-phase faults in the motor, based on where the additional degrees of freedom are used, two different fault-tolerance current calculation schemes are adopted and the torque results are compared. Decoupling of the inner motor and outer motor is investigated under fault-tolerant conditions in parallel drive mode. The finite element analysis (FMA results and co-simulation results based on Simulink-Simplorer-Maxwell verify the effectiveness of the techniques.

  19. Efficient Fault-Tolerant Event Query Algorithm in Distributed Wireless Sensor Networks

    OpenAIRE

    Rongbo Zhu

    2010-01-01

    To overcome the faulty data query problem to improve the accuracy of data query, an efficient fault-tolerant event query algorithm (FTEQ) is proposed, which takes the short-term and long-term spatial and temporal similarities between sensors and environment into considerations. An imprecise and missing data correction algorithm based on Kalman filter is proposed to correct fault sensing data, and a score rank algorithm also is proposed to assign each sensor an appropriate value to reflect the...

  20. Rconfigurable adaptive fuzzy fault-hiding control for greenhouse climate control system

    DEFF Research Database (Denmark)

    Hameed, Ibrahim; El-Madbouly, E I; Abdo, M I

    2016-01-01

    Modern greenhouses are equipped with different components for providing a comfortable climate for plant growth. A component malfunction may result in loss of production. Therefore, it is desirable to design a control system, which is stable, and is able to provide an acceptable degraded performance...... even in the faulty case. In this paper, an active fault tolerant control scheme to compensate for actuator and/or sensor faults in the greenhouse climate system is designed. The control system consists of a sensitive and reliable Fault Detection and Diagnosis (FDD) mechanism for different types...... of faults in presence of system disturbances and a robust reconfigurable control design based on fault-hiding principal in which the fault is hidden from the nominal controller and the fault effects are compensated. In this approach, a set of virtual actuators and virtual sensors are used to guarantee...

  1. Wireless Avionics Packet to Support Fault Tolerance for Flight Applications

    Science.gov (United States)

    Block, Gary L.; Whitaker, William D.; Dillon, James W.; Lux, James P.; Ahmad, Mohammad

    2009-01-01

    In this protocol and packet format, data traffic is monitored by all network interfaces to determine the health of transmitter and subsystems. When failures are detected, the network inter face applies its recover y policies to provide continued service despite the presence of faults. The protocol, packet format, and inter face are independent of the data link technology used. The current demonstration system supports both commercial off-the-shelf wireless connections and wired Ethernet connections. Other technologies such as 1553 or serial data links can be used for the network backbone. The Wireless Avionics packet is divided into three parts: a header, a data payload, and a checksum. The header has the following components: magic number, version, quality of service, time to live, sending transceiver, function code, payload length, source Application Data Interface (ADI) address, destination ADI address, sending node address, target node address, and a sequence number. The magic number is used to identify WAV packets, and allows the packet format to be updated in the future. The quality of service field allows routing decisions to be made based on this value and can be used to route critical management data over a dedicated channel. The time to live value is used to discard misrouted packets while the source transceiver is updated at each hop. This information is used to monitor the health of each transceiver in the network. To identify the packet type, the function code is used. Besides having a regular data packet, the system supports diagnostic packets for fault detection and isolation. The payload length specifies the number of data bytes in the payload, and this supports variable-length packets in the network. The source ADI is the address of the originating interface. This can be used by the destination application to identify the originating source of the packet where the address consists of a subnet, subsystem class within the subnet, a subsystem unit

  2. Fault-tolerant linear optical quantum computing with small-amplitude coherent States.

    Science.gov (United States)

    Lund, A P; Ralph, T C; Haselgrove, H L

    2008-01-25

    Quantum computing using two coherent states as a qubit basis is a proposed alternative architecture with lower overheads but has been questioned as a practical way of performing quantum computing due to the fragility of diagonal states with large coherent amplitudes. We show that using error correction only small amplitudes (alpha>1.2) are required for fault-tolerant quantum computing. We study fault tolerance under the effects of small amplitudes and loss using a Monte Carlo simulation. The first encoding level resources are orders of magnitude lower than the best single photon scheme.

  3. Implementation of a fault-tolerant PACS over a grid architecture

    Science.gov (United States)

    Gutierrez, Marco A.; Santos, Carlos S.; Moreno, Ramon A.; Kobayashi, Luiz O. M.; Furuie, Sergio S.; Freire, Sergio M.; Floriano, Daniel B.; Oliveira, Carlos S.; João, Mario, Jr.; Gismondi, Ronaldo C.

    2006-03-01

    The goal of this paper is to describe the experience of the Heart Institute (InCor) on the implementation of a fault-tolerant Picture Archiving and Communication System (PACS) over a data grid architecture. The system is centered on a DICOM image server with a distributed storage and failover capability. The proposed data grid architecture is deployed over a gigabit Ethernet network which integrates the two main public Hospitals in Sao Paulo and one University Hospital in Rio de Janeiro, both in Brazil. Distributed data storage in the three sites is managed by the Storage Resource Broker (SRB) developed at the University of California at San Diego. The architecture of the implemented PACS image server can be divided into two major functional modules: a) DICOM protocol handler; b) Distributed storage of image data. Fault-tolerance is achieved by injecting redundancy into the modules, which are provided with failover capability. The DICOM protocol handler comprises a series of server processes hosted by different machines and a load-balancer node which distributes the computational load among the servers. The load balancer is provided with a backup node which is triggered in case of failure, thus assuring the continuous operation of the system. Distributed storage of image data is implemented as a thin software layer over the SRB. Image data are replicated at the three sites, so the PACS server is able to retrieve image data even when only a single site is available. A prototype of the DICOM image server has been deployed in this environment and is currently under evaluation.

  4. A Benchmark Evaluation of Fault Tolerant Wind Turbine Control Concepts

    DEFF Research Database (Denmark)

    Odgaard, Peter Fogh; Stoustrup, Jakob

    2015-01-01

    . A benchmark model for wind turbine fault detection and isolation, and FTC has previously been proposed. Based on this benchmark, an international competition on wind turbine FTC was announced. In this brief, the top three solutions from that competition are presented and evaluated. The analysis shows that all...

  5. A Fault Tolerant, Dynamic and Low Latency BDII Architecture for Grids

    CERN Document Server

    Osman, Asif; Batool, Naheed; McClatchey, Richard

    2012-01-01

    The current BDII model relies on information gathering from agents that run on each core node of a Grid. This information is then published into a Grid wide information resource known as Top BDII. The Top level BDIIs are updated typically in cycles of a few minutes each. A new BDDI architecture is proposed and described in this paper based on the hypothesis that only a few attribute values change in each BDDI information cycle and consequently it may not be necessary to update each parameter in a cycle. It has been demonstrated that significant performance gains can be achieved by exchanging only the information about records that changed during a cycle. Our investigations have led us to implement a low latency and fault tolerant BDII system that involves only minimal data transfer and facilitates secure transactions in a Grid environment.

  6. Fault-Tolerant Robot Programming through Simulation with Realistic Sensor Models

    Directory of Open Access Journals (Sweden)

    Axel Waggershauser

    2008-11-01

    Full Text Available We introduce a simulation system for mobile robots that allows a realistic interaction of multiple robots in a common environment. The simulated robots are closely modeled after robots from the EyeBot family and have an identical application programmer interface. The simulation supports driving commands at two levels of abstraction as well as numerous sensors such as shaft encoders, infrared distance sensors, and compass. Simulation of on-board digital cameras via synthetic images allows the use of image processing routines for robot control within the simulation. Specific error models for actuators, distance sensors, camera sensor, and wireless communication have been implemented. Progressively increasing error levels for an application program allows for testing and improving its robustness and fault-tolerance.

  7. Experimental fault-tolerant universal quantum gates with solid-state spins under ambient conditions

    Science.gov (United States)

    Rong, Xing; Geng, Jianpei; Shi, Fazhan; Liu, Ying; Xu, Kebiao; Ma, Wenchao; Kong, Fei; Jiang, Zhen; Wu, Yang; Du, Jiangfeng

    2015-01-01

    Quantum computation provides great speedup over its classical counterpart for certain problems. One of the key challenges for quantum computation is to realize precise control of the quantum system in the presence of noise. Control of the spin-qubits in solids with the accuracy required by fault-tolerant quantum computation under ambient conditions remains elusive. Here, we quantitatively characterize the source of noise during quantum gate operation and demonstrate strategies to suppress the effect of these. A universal set of logic gates in a nitrogen-vacancy centre in diamond are reported with an average single-qubit gate fidelity of 0.999952 and two-qubit gate fidelity of 0.992. These high control fidelities have been achieved at room temperature in naturally abundant 13C diamond via composite pulses and an optimized control method. PMID:26602456

  8. ANDY: A general, fault-tolerant tool for database searching oncomputer clusters

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Andrew; Chandonia, John-Marc; Brenner, Steven E.

    2005-12-21

    Summary: ANDY (seArch coordination aND analYsis) is a set ofPerl programs and modules for distributing large biological databasesearches, and in general any sequence of commands, across the nodes of aLinux computer cluster. ANDY is compatible with several commonly usedDistributed Resource Management (DRM) systems, and it can be easilyextended to new DRMs. A distinctive feature of ANDY is the choice ofeither dedicated or fair-use operation: ANDY is almost as efficient assingle-purpose tools that require a dedicated cluster, but it runs on ageneral-purpose cluster along with any other jobs scheduled by a DRM.Other features include communication through named pipes for performance,flexible customizable routines for error-checking and summarizingresults, and multiple fault-tolerance mechanisms. Availability: ANDY isfreely available and may be obtained fromhttp://compbio.berkeley.edu/proj/andy; this site also containssupplemental data and figures and amore detailed overview of thesoftware.

  9. Fuzzy Logic Method for Enhancement Fault-Tolerant of Cluster Head in Wireless Sensor Networks Clustering

    Directory of Open Access Journals (Sweden)

    Farnaz Pakdeland

    2016-08-01

    Full Text Available Wireless sensor network is comprised of several sensor nodes. The retaining factors influence the network operation. In the clustering structure the cluster head failure can cause loss of information.The aim of this paper is to increase tolerance error in the cluster head node. At first, paying attention to the producing balance in the density of the cluster cause to postpone the death time of the cluster head node and lessen the collision due to the lack of the energy balance in clusters. The innovation in this stage is formed by using two fuzzy logic systems. One in the phase of evaluation of the cluster head chance, and the other in the phase of producing balance and the nodes migration to the qualified clusters to increase balance, Then the focus is on recognizing and repairing the cluster head fault.

  10. ADHOCFTSIM: A Simulator of Fault Tolerence In the AD-HOC Networks

    Directory of Open Access Journals (Sweden)

    Esma Insaf Djebbar

    2010-11-01

    Full Text Available The flexibility and diversity of Wireless Mobile Networks offer many opportunities that are not alwaystaken into account by existing distributed systems. In particular, the proliferation of mobile users and theuse of mobile Ad-Hoc promote the formation of collaborative groups to share resources. We propose asolution for the management of fault tolerance in the Ad-Hoc networks, combining the functions neededto better availability of data. Our contribution takes into account the characteristics of mobile terminalsin order to reduce the consumption of resources critical that energy, and to minimize the loss ofinformation. Our solution is based on the formation of clusters, where each is managed by a node leader.This solution is mainly composed of four sub-services, namely: prediction, replication, management ofnodes in the cluster and supervision. We have shown, using several sets of simulation, that our solution istwofold: minimizing the energy consumption which increases the life of the network and better supportdeal with requests lost.

  11. A Replication-Based Mechanism for Fault Tolerance in MapReduce Framework

    Directory of Open Access Journals (Sweden)

    Yang Liu

    2015-01-01

    Full Text Available MapReduce is a programming model and an associated implementation for processing and generating large data sets with a parallel, distributed algorithm on a cluster. In cloud environment, node and task failure are no longer accidental but a common feature of large-scale systems. Current rescheduling-based fault tolerance method in MapReduce framework failed to fully consider the location of distributed data and the computation and storage overhead of rescheduling failure tasks. Thus, a single node failure will increase the completion time dramatically. In this paper, a replication-based mechanism is proposed, which takes both task and node failure into consideration. Experimental results show that, compared with default mechanism in Hadoop, our mechanism can significantly improve the performance at failure time, with more than 30% decreasing in execution time.

  12. Fusion of Built in Test (BIT) Technologies with Embeddable Fault Tolerant Techniques for Power System and Drives in Space Exploration Project

    Data.gov (United States)

    National Aeronautics and Space Administration — As NASA develops next generation space exploration systems as part of the Constellation program, new prognostics and health management tools are needed to ensure...

  13. CMOS active pixel sensor for fault tolerance and background illumination subtraction

    OpenAIRE

    Cheung, Yu Hin (Desmond)

    2005-01-01

    As the CMOS active pixel sensor evolves, its weaknesses are being overcome and its strengths start to surpass that of the charge-coupled device. This thesis discusses two novel APS designs. The first novel APS design was a Fault Tolerance Active Pixel Sensor (FTAPS) to increase a pixel's tolerance to defects. By dividing a regular APS pixel into two halves, the reliability of the pixel is increased, resulting in higher fabrication yield, longer pixel life time, and reduction in cost. Photodio...

  14. Fault Diagnosis for Electrical Distribution Systems using Structural Analysis

    DEFF Research Database (Denmark)

    Knüppel, Thyge; Blanke, Mogens; Østergaard, Jacob

    2014-01-01

    relations (ARR) are likely to change. The algorithms used for diagnosis may need to change accordingly, and finding efficient methods to ARR generation is essential to employ fault-tolerant methods in the grid. Structural analysis (SA) is based on graph-theoretical results, that offer to find analytic...... redundancies in large sets of equations only from the structure (topology) of the equations. A salient feature is automated generation of redundancy relations. The method is indeed feasible in electrical networks where circuit theory and network topology together formulate the constraints that define...... analysis of power systems, it demonstrates detection and isolation of failures in a network, and shows how typical faults are diagnosed. Nonlinear fault simulations illustrate the results....

  15. Minimalist fault-tolerance techniques for mitigating single-event effects in non-radiation-hardened microcontrollers

    Science.gov (United States)

    Caldwell, Douglas Wyche

    Commercial microcontrollers--monolithic integrated circuits containing microprocessor, memory and various peripheral functions--such as are used in industrial, automotive and military applications, present spacecraft avionics system designers an appealing mix of higher performance and lower power together with faster system-development time and lower unit costs. However, these parts are not radiation-hardened for application in the space environment and Single-Event Effects (SEE) caused by high-energy, ionizing radiation present a significant challenge. Mitigating these effects with techniques which require minimal additional support logic, and thereby preserve the high functional density of these devices, can allow their benefits to be realized. This dissertation uses fault-tolerance to mitigate the transient errors and occasional latchups that non-hardened microcontrollers can experience in the space radiation environment. Space systems requirements and the historical use of fault-tolerant computers in spacecraft provide context. Space radiation and its effects in semiconductors define the fault environment. A reference architecture is presented which uses two or three microcontrollers with a combination of hardware and software voting techniques to mitigate SEE. A prototypical spacecraft function (an inertial measurement unit) is used to illustrate the techniques and to explore how real application requirements impact the fault-tolerance approach. Low-cost approaches which leverage features of existing commercial microcontrollers are analyzed. A high-speed serial bus is used for voting among redundant devices and a novel wire-OR output voting scheme exploits the bidirectional controls of I/O pins. A hardware testbed and prototype software were constructed to evaluate two- and three-processor configurations. Simulated Single-Event Upsets (SEUs) were injected at high rates and the response of the system monitored. The resulting statistics were used to evaluate

  16. Fault isolability conditions for linear systems with additive faults

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik; Stoustrup, Jakob

    2006-01-01

    In this paper, we shall show that an unlimited number of additive single faults can be isolated under mild conditions if a general isolation scheme is applied. Multiple faults are also covered. The approach is algebraic and is based on a set representation of faults, where all faults within a set...

  17. Testing Distributed ABS System with Fault Injection

    Science.gov (United States)

    Trawczyński, Dawid; Sosnowski, Janusz; Gawkowski, Piotr

    The paper deals with the problem of adapting software implemented fault injection technique (SWIFI) to evaluate dependability of reactive microcontroller systems. We present an original methodology of disturbing controller operation and analyzing fault effects taking into account reactions of the controlled object and the impact of the system environment. Faults can be injected randomly (in space and time) or targeted at the most sensitive elements of the controller to check it at high stresses. This approach allows identifying rarely encountered problems, usually missed in classical approaches. The developed methodology has been used successfully to verify dependability of ABS system. Experimental results are commented in the paper.

  18. Data-driven design of fault diagnosis systems nonlinear multimode processes

    CERN Document Server

    Haghani Abandan Sari, Adel

    2014-01-01

    In many industrial applications early detection and diagnosis of abnormal behavior of the plant is of great importance. During the last decades, the complexity of process plants has been drastically increased, which imposes great challenges in development of model-based monitoring approaches and it sometimes becomes unrealistic for modern large-scale processes. The main objective of Adel Haghani Abandan Sari is to study efficient fault diagnosis techniques for complex industrial systems using process historical data and considering the nonlinear behavior of the process. To this end, different methods are presented to solve the fault diagnosis problem based on the overall behavior of the process and its dynamics. Moreover, a novel technique is proposed for fault isolation and determination of the root-cause of the faults in the system, based on the fault impacts on the process measurements. Contents Process monitoring Fault diagnosis and fault-tolerant control Data-driven approaches and decision making Target...

  19. A Fault-Tolerant Multiple Sensor Fusion Approach Applied to UAV Attitude Estimation

    Directory of Open Access Journals (Sweden)

    Yu Gu

    2016-01-01

    Full Text Available A novel sensor fusion design framework is presented with the objective of improving the overall multisensor measurement system performance and achieving graceful degradation following individual sensor failures. The Unscented Information Filter (UIF is used to provide a useful tool for combining information from multiple sources. A two-step off-line and on-line calibration procedure refines sensor error models and improves the measurement performance. A Fault Detection and Identification (FDI scheme crosschecks sensor measurements and simultaneously monitors sensor biases. Low-quality or faulty sensor readings are then rejected from the final sensor fusion process. The attitude estimation problem is used as a case study for the multiple sensor fusion algorithm design, with information provided by a set of low-cost rate gyroscopes, accelerometers, magnetometers, and a single-frequency GPS receiver’s position and velocity solution. Flight data collected with an Unmanned Aerial Vehicle (UAV research test bed verifies the sensor fusion, adaptation, and fault-tolerance capabilities of the designed sensor fusion algorithm.

  20. Cooperation-induced topological complexity: a promising road to fault tolerance and Hebbian learning

    Directory of Open Access Journals (Sweden)

    Malgorzata eTuralska

    2012-03-01

    Full Text Available According to an increasing number of researchers intelligence emerges from criticality as a consequence of locality breakdown and long-range correlation, well known properties of phase transition processes. We study a model of interacting units, as an idealization of real cooperative systems such as the brain or a flock of birds, for the purpose of discussing the emergence of long-range correlation from the coupling of any unit with its nearest neighbors. We focus on the critical condition that has been recently shown to maximize information transport and we study the topological structure of the network of dynamically linked nodes. Although the topology of this network depends on the arbitrary choice of correlation threshold, namely the correlation intensity selected to establish a link between two nodes; the numerical calculations of this paper afford some important indications on the dynamically induced topology. The first important property is the emergence of a perception length as large as the flock size, thanks to some nodes with a large number of links, thus playing the leadership role. All the units are equivalent and leadership moves in time from one to another set of nodes, thereby insuring fault tolerance. Then we focus on the correlation threshold generating a scale-free topology with power index and we find that if this topological structure is selected to establish consensus through the linked nodes, the control parameter necessary to generate criticality is close to the critical value corresponding to the all-to-all coupling condition. We find that criticality in this case generates also a third state, corresponding to a total lack of consensus. However, we make a numerical analysis of the dynamically induced network, and we find that it consists of two almost independent structures, each of which is equivalent to a network in the all-to-all coupling condition. We argue that these results are compatible with Hebbian learning and