WorldWideScience

Sample records for redundant control surfaces

  1. A Modular Approach to Redundant Robot Control

    International Nuclear Information System (INIS)

    Anderson, R.J.

    1997-12-01

    This paper describes a modular approach for computing redundant robot kinematics. First some conventional redundant control methods are presented and shown to be 'passive control laws', i.e. they can be represented by a network consisting of passive elements. These networks are then put into modular form by applying scattering operator techniques. Additional subnetwork modules can then be added to further shape the motion. Modules for obstacle detection, joint limit avoidance, proximity sensing, and for imposing nonlinear velocity constraints are presented. The resulting redundant robot control system is modular, flexible and robust

  2. Resolving Actuator Redundancy - Control Allocation vs. Linear Quadratic Control

    OpenAIRE

    Härkegård, Ola

    2004-01-01

    When designing control laws for systems with more inputs than controlled variables, one issue to consider is how to deal with actuator redundancy. Two tools for distributing the control effort among a redundant set of actuators are control allocation and linear quadratic control design. In this paper, we investigate the relationship between these two design tools when a quadratic performance index is used for control allocation. We show that for a particular class of linear systems, they give...

  3. Motion control of musculoskeletal systems with redundancy.

    Science.gov (United States)

    Park, Hyunjoo; Durand, Dominique M

    2008-12-01

    Motion control of musculoskeletal systems for functional electrical stimulation (FES) is a challenging problem due to the inherent complexity of the systems. These include being highly nonlinear, strongly coupled, time-varying, time-delayed, and redundant. The redundancy in particular makes it difficult to find an inverse model of the system for control purposes. We have developed a control system for multiple input multiple output (MIMO) redundant musculoskeletal systems with little prior information. The proposed method separates the steady-state properties from the dynamic properties. The dynamic control uses a steady-state inverse model and is implemented with both a PID controller for disturbance rejection and an artificial neural network (ANN) feedforward controller for fast trajectory tracking. A mechanism to control the sum of the muscle excitation levels is also included. To test the performance of the proposed control system, a two degree of freedom ankle-subtalar joint model with eight muscles was used. The simulation results show that separation of steady-state and dynamic control allow small output tracking errors for different reference trajectories such as pseudo-step, sinusoidal and filtered random signals. The proposed control method also demonstrated robustness against system parameter and controller parameter variations. A possible application of this control algorithm is FES control using multiple contact cuff electrodes where mathematical modeling is not feasible and the redundancy makes the control of dynamic movement difficult.

  4. Interaction control of a redundant mobile manipulator

    International Nuclear Information System (INIS)

    Chung, J.H.; Velinsky, S.A.; Hess, R.A.

    1998-01-01

    This paper discusses the modeling and control of a spatial mobile manipulator that consists of a robotic manipulator mounted on a wheeled mobile platform. The Lagrange-d'Alembert formulation is used to obtain a concise description of the dynamics of the system, which is subject to nonholonomic constraints. The complexity of the model is increased by introducing kinematic redundancy, which is created when a multilinked manipulator is used. The kinematic redundancy is resolved by decomposing the mobile manipulator into two subsystems: the mobile platform and the manipulator. The redundancy resolution scheme employs a nonlinear interaction-control algorithm, which is developed and applied to coordinate the two subsystems' controllers. The subsystem controllers are independently designed, based on each subsystem's dynamic characteristics. Simulation results show the promise of the developed algorithm

  5. Application study of EPICS-based redundant method for reactor control system

    International Nuclear Information System (INIS)

    Zhang Ning; Han Lifeng; Chen Yongzhong; Guo Bing; Yin Congcong

    2013-01-01

    In the reactor control system prototype development of TMSR (Thorium Molten Salt Reactor system, CAS) project, EPICS (Experimental Physics and Industrial Control System) is adopted as Instrument and Control software platform. For the aim of IOC (Input/Output Controller) redundancy and data synchronization of the system, the EPICS-based RMT (Redundancy Monitor Task ) software package and its data-synchronization component CCE (Continuous Control Executive) were introduced. By the development of related IOC driver, redundant switch-over control of server IOC was implemented. The method of redundancy implementation using RMT in server and redundancy performance test for power control system are discussed in this paper. (authors)

  6. Redundant measurements for controlling errors

    International Nuclear Information System (INIS)

    Ehinger, M.H.; Crawford, J.M.; Madeen, M.L.

    1979-07-01

    Current federal regulations for nuclear materials control require consideration of operating data as part of the quality control program and limits of error propagation. Recent work at the BNFP has revealed that operating data are subject to a number of measurement problems which are very difficult to detect and even more difficult to correct in a timely manner. Thus error estimates based on operational data reflect those problems. During the FY 1978 and FY 1979 R and D demonstration runs at the BNFP, redundant measurement techniques were shown to be effective in detecting these problems to allow corrective action. The net effect is a reduction in measurement errors and a significant increase in measurement sensitivity. Results show that normal operation process control measurements, in conjunction with routine accountability measurements, are sensitive problem indicators when incorporated in a redundant measurement program

  7. Dynamic Control of Kinematically Redundant Robotic Manipulators

    Directory of Open Access Journals (Sweden)

    Erling Lunde

    1987-07-01

    Full Text Available Several methods for task space control of kinematically redundant manipulators have been proposed in the literature. Most of these methods are based on a kinematic analysis of the manipulator. In this paper we propose a control algorithm in which we are especially concerned with the manipulator dynamics. The algorithm is particularly well suited for the class of redundant manipulators consisting of a relatively small manipulator mounted on a larger positioning part.

  8. Optimization of robustness of interdependent network controllability by redundant design.

    Directory of Open Access Journals (Sweden)

    Zenghu Zhang

    Full Text Available Controllability of complex networks has been a hot topic in recent years. Real networks regarded as interdependent networks are always coupled together by multiple networks. The cascading process of interdependent networks including interdependent failure and overload failure will destroy the robustness of controllability for the whole network. Therefore, the optimization of the robustness of interdependent network controllability is of great importance in the research area of complex networks. In this paper, based on the model of interdependent networks constructed first, we determine the cascading process under different proportions of node attacks. Then, the structural controllability of interdependent networks is measured by the minimum driver nodes. Furthermore, we propose a parameter which can be obtained by the structure and minimum driver set of interdependent networks under different proportions of node attacks and analyze the robustness for interdependent network controllability. Finally, we optimize the robustness of interdependent network controllability by redundant design including node backup and redundancy edge backup and improve the redundant design by proposing different strategies according to their cost. Comparative strategies of redundant design are conducted to find the best strategy. Results shows that node backup and redundancy edge backup can indeed decrease those nodes suffering from failure and improve the robustness of controllability. Considering the cost of redundant design, we should choose BBS (betweenness-based strategy or DBS (degree based strategy for node backup and HDF(high degree first for redundancy edge backup. Above all, our proposed strategies are feasible and effective at improving the robustness of interdependent network controllability.

  9. Redundancy scheme for multi-layered accelerator control system

    International Nuclear Information System (INIS)

    Chauhan, Amit; Fatnani, Pravin

    2009-01-01

    The control system for SRS Indus-2 has three-layered architecture. There are VMEbus based stations at the lower two layers that are controlled by their respective CPU board. The 'Profibus' fieldbus standard is used for communication between these VME stations distributed in the field. There is a Profibus controller board at each station to implement the communication protocol. The mode of communication is master-slave (command-response) type. This paper proposes a scheme to implement redundancy at the lower two layers namely Layer-2 (Supervisory Layer / Profibus-master) and Layer-3 (Equipment Unit Interface Layer / Profibus-slave). The redundancy is for both the CPU and the communication board. The scheme uses two CPU boards and two Profi controller boards at each L-3 station. This helps in decreasing any downtime resulting either from CPU faults or communication board faults that are placed in the field area. Redundancy of Profi boards provides two active communication channels between the stations that can be used in different ways thereby increasing the availability on a communication link. Redundancy of CPU boards provides certain level of auto fault-recovery as one CPU remains active and the other CPU remains in standby mode, which takes over the control of VMEbus in case of any fault in the main CPU. (author)

  10. REDUNDANT ELECTRIC MOTOR DRIVE CONTROL UNIT DESIGN USING AUTOMATA-BASED APPROACH

    Directory of Open Access Journals (Sweden)

    Yuri Yu. Yankin

    2014-11-01

    Full Text Available Implementation of redundant unit for motor drive control based on programmable logic devices is discussed. Continuous redundancy method is used. As compared to segregated standby redundancy and whole system standby redundancy, such method provides preservation of all unit functions in case of redundancy and gives the possibility for continuous monitoring of major and redundant elements. Example of that unit is given. Electric motor drive control channel block diagram contains two control units – the major and redundant; it also contains four power supply units. Control units programming was carried out using automata-based approach. Electric motor drive control channel model was developed; it provides complex simulation of control state-machine and power converter. Through visibility and hierarchy of finite state machines debug time was shortened as compared to traditional programming. Control state-machine description using hardware description language is required for its synthesis with FPGA-devices vendor design software. This description was generated automatically by MATLAB software package. To verify results two prototype control units, two prototype power supply units, and device mock-up were developed and manufactured. Units were installed in the device mock-up. Prototype units were created in accordance with requirements claimed to deliverable hardware. Control channel simulation and tests results in the perfect state and during imitation of major element fault are presented. Automata-based approach made it possible to observe and debug control state-machine transitions during simulation of transient processes, occurring at imitation of faults. Results of this work can be used in development of fault tolerant electric motor drive control channels.

  11. A control method for manipulators with redundancy

    International Nuclear Information System (INIS)

    Furusho, Junji; Usui, Hiroyuki

    1989-01-01

    Redundant manipulators have more ability than nonredundant ones in many aspects such as avoiding obstacles, avoiding singular states, etc. In this paper, a control algorithm for redundant manipulators working under the circumstance in the presence of obstacles is presented. First, the measure of manipulability for robot manipulators under obstacle circumstances is defined. Then, the control algorithm for the obstacle avoidance is derived by using this measure of manipulability. The obstacle avoidance and the maintenance of good posture are simultaneously achieved by this algorithm. Lastly, an experiment and simulation results using an eight degree of freedom manipulator are shown. (author)

  12. Case studies in configuration control for redundant robots

    Science.gov (United States)

    Seraji, H.; Lee, T.; Colbaugh, R.; Glass, K.

    1989-01-01

    A simple approach to configuration control of redundant robots is presented. The redundancy is utilized to control the robot configuration directly in task space, where the task will be performed. A number of task-related kinematic functions are defined and combined with the end-effector coordinates to form a set of configuration variables. An adaptive control scheme is then utilized to ensure that the configuration variables track the desired reference trajectories as closely as possible. Simulation results are presented to illustrate the control scheme. The scheme has also been implemented for direct online control of a PUMA industrial robot, and experimental results are presented. The simulation and experimental results validate the configuration control scheme for performing various realistic tasks.

  13. Impedance Control of a Redundant Parallel Manipulator

    DEFF Research Database (Denmark)

    Méndez, Juan de Dios Flores; Schiøler, Henrik; Madsen, Ole

    2017-01-01

    This paper presents the design of Impedance Control to a redundantly actuated Parallel Kinematic Manipulator. The proposed control is based on treating each limb as a single system and their connection through the internal interaction forces. The controller introduces a stiffness and damping...

  14. Reliability Analysis Multiple Redundancy Controller for Nuclear Safety Systems

    International Nuclear Information System (INIS)

    Son, Gwangseop; Kim, Donghoon; Son, Choulwoong

    2013-01-01

    This controller is configured for multiple modular redundancy (MMR) composed of dual modular redundancy (DMR) and triple modular redundancy (TMR). The architecture of MRC is briefly described, and the Markov model is developed. Based on the model, the reliability and Mean Time To Failure (MTTF) are analyzed. In this paper, the architecture of MRC for nuclear safety systems is described. The MRC is configured for multiple modular redundancy (MMR) composed of dual modular redundancy (DMR) and triple modular redundancy (TMR). Markov models for MRC architecture was developed, and then the reliability was analyzed by using the model. From the reliability analyses for the MRC, it is obtained that the failure rate of each module in the MRC should be less than 2 Χ 10 -4 /hour and the MTTF average increase rate depending on FCF increment, i. e. ΔMTTF/ΔFCF, is 4 months/0.1

  15. Method and system for redundancy management of distributed and recoverable digital control system

    Science.gov (United States)

    Stange, Kent (Inventor); Hess, Richard (Inventor); Kelley, Gerald B (Inventor); Rogers, Randy (Inventor)

    2012-01-01

    A method and system for redundancy management is provided for a distributed and recoverable digital control system. The method uses unique redundancy management techniques to achieve recovery and restoration of redundant elements to full operation in an asynchronous environment. The system includes a first computing unit comprising a pair of redundant computational lanes for generating redundant control commands. One or more internal monitors detect data errors in the control commands, and provide a recovery trigger to the first computing unit. A second redundant computing unit provides the same features as the first computing unit. A first actuator control unit is configured to provide blending and monitoring of the control commands from the first and second computing units, and to provide a recovery trigger to each of the first and second computing units. A second actuator control unit provides the same features as the first actuator control unit.

  16. In-flight performance optimization for rotorcraft with redundant controls

    Science.gov (United States)

    Ozdemir, Gurbuz Taha

    A conventional helicopter has limits on performance at high speeds because of the limitations of main rotor, such as compressibility issues on advancing side or stall issues on retreating side. Auxiliary lift and thrust components have been suggested to improve performance of the helicopter substantially by reducing the loading on the main rotor. Such a configuration is called the compound rotorcraft. Rotor speed can also be varied to improve helicopter performance. In addition to improved performance, compound rotorcraft and variable RPM can provide a much larger degree of control redundancy. This additional redundancy gives the opportunity to further enhance performance and handling qualities. A flight control system is designed to perform in-flight optimization of redundant control effectors on a compound rotorcraft in order to minimize power required and extend range. This "Fly to Optimal" (FTO) control law is tested in simulation using the GENHEL model. A model of the UH-60, a compound version of the UH-60A with lifting wing and vectored thrust ducted propeller (VTDP), and a generic compound version of the UH-60A with lifting wing and propeller were developed and tested in simulation. A model following dynamic inversion controller is implemented for inner loop control of roll, pitch, yaw, heave, and rotor RPM. An outer loop controller regulates airspeed and flight path during optimization. A Golden Section search method was used to find optimal rotor RPM on a conventional helicopter, where the single redundant control effector is rotor RPM. The FTO builds off of the Adaptive Performance Optimization (APO) method of Gilyard by performing low frequency sweeps on a redundant control for a fixed wing aircraft. A method based on the APO method was used to optimize trim on a compound rotorcraft with several redundant control effectors. The controller can be used to optimize rotor RPM and compound control effectors through flight test or simulations in order to

  17. Management of redundancy in flight control systems using optimal decision theory

    Science.gov (United States)

    1981-01-01

    The problem of using redundancy that exists between dissimilar systems in aircraft flight control is addressed. That is, using the redundancy that exists between a rate gyro and an accelerometer--devices that have dissimilar outputs which are related only through the dynamics of the aircraft motion. Management of this type of redundancy requires advanced logic so that the system can monitor failure status and can reconfigure itself in the event of one or more failures. An optimal decision theory was tutorially developed for the management of sensor redundancy and the theory is applied to two aircraft examples. The first example is the space shuttle and the second is a highly maneuvering high performance aircraft--the F8-C. The examples illustrate the redundancy management design process and the performance of the algorithms presented in failure detection and control law reconfiguration.

  18. Kinematically Optimal Robust Control of Redundant Manipulators

    Science.gov (United States)

    Galicki, M.

    2017-12-01

    This work deals with the problem of the robust optimal task space trajectory tracking subject to finite-time convergence. Kinematic and dynamic equations of a redundant manipulator are assumed to be uncertain. Moreover, globally unbounded disturbances are allowed to act on the manipulator when tracking the trajectory by the endeffector. Furthermore, the movement is to be accomplished in such a way as to minimize both the manipulator torques and their oscillations thus eliminating the potential robot vibrations. Based on suitably defined task space non-singular terminal sliding vector variable and the Lyapunov stability theory, we derive a class of chattering-free robust kinematically optimal controllers, based on the estimation of transpose Jacobian, which seem to be effective in counteracting both uncertain kinematics and dynamics, unbounded disturbances and (possible) kinematic and/or algorithmic singularities met on the robot trajectory. The numerical simulations carried out for a redundant manipulator of a SCARA type consisting of the three revolute kinematic pairs and operating in a two-dimensional task space, illustrate performance of the proposed controllers as well as comparisons with other well known control schemes.

  19. Robust Redundant Input Reliable Tracking Control for Omnidirectional Rehabilitative Training Walker

    Directory of Open Access Journals (Sweden)

    Ping Sun

    2014-01-01

    Full Text Available The problem of robust reliable tracking control on the omnidirectional rehabilitative training walker is examined. The new nonlinear redundant input method is proposed when one wheel actuator fault occurs. The aim of the study is to design an asymptotically stable controller that can guarantee the safety of the user and ensure tracking on a training path planned by a physical therapist. The redundant degrees of freedom safety control and the asymptotically zero state detectable concept of the walker are presented, the model of redundant degree is constructed, and the property of center of gravity constant shift is obtained. A controller that can satisfy asymptotic stability is obtained using a common Lyapunov function for admissible uncertainties resulting from an actuator fault. Simulation results confirm the effectiveness of the proposed method and verify that the walker can provide safe sequential motion when one wheel actuator is at fault.

  20. Input relegation control for gross motion of a kinematically redundant manipulator

    Energy Technology Data Exchange (ETDEWEB)

    Unseren, M.A.

    1992-10-01

    This report proposes a method for resolving the kinematic redundancy of a serial link manipulator moving in a three-dimensional workspace. The underspecified problem of solving for the joint velocities based on the classical kinematic velocity model is transformed into a well-specified problem. This is accomplished by augmenting the original model with additional equations which relate a new vector variable quantifying the redundant degrees of freedom (DOF) to the joint velocities. The resulting augmented system yields a well specified solution for the joint velocities. Methods for selecting the redundant DOF quantifying variable and the transformation matrix relating it to the joint velocities are presented so as to obtain a minimum Euclidean norm solution for the joint velocities. The approach is also applied to the problem of resolving the kinematic redundancy at the acceleration level. Upon resolving the kinematic redundancy, a rigid body dynamical model governing the gross motion of the manipulator is derived. A control architecture is suggested which according to the model, decouples the Cartesian space DOF and the redundant DOF.

  1. Redundant actuator development study. [flight control systems for supersonic transport aircraft

    Science.gov (United States)

    Ryder, D. R.

    1973-01-01

    Current and past supersonic transport configurations are reviewed to assess redundancy requirements for future airplane control systems. Secondary actuators used in stability augmentation systems will probably be the most critical actuator application and require the highest level of redundancy. Two methods of actuator redundancy mechanization have been recommended for further study. Math models of the recommended systems have been developed for use in future computer simulations. A long range plan has been formulated for actuator hardware development and testing in conjunction with the NASA Flight Simulator for Advanced Aircraft.

  2. Kinematic control of redundant robots and the motion optimizability measure.

    Science.gov (United States)

    Li, L; Gruver, W A; Zhang, Q; Yang, Z

    2001-01-01

    This paper treats the kinematic control of manipulators with redundant degrees of freedom. We derive an analytical solution for the inverse kinematics that provides a means for accommodating joint velocity constraints in real time. We define the motion optimizability measure and use it to develop an efficient method for the optimization of joint trajectories subject to multiple criteria. An implementation of the method for a 7-dof experimental redundant robot is present.

  3. 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.

  4. Repetitive motion planning and control of redundant robot manipulators

    CERN Document Server

    Zhang, Yunong

    2013-01-01

    Repetitive Motion Planning and Control of Redundant Robot Manipulators presents four typical motion planning schemes based on optimization techniques, including the fundamental RMP scheme and its extensions. These schemes are unified as quadratic programs (QPs), which are solved by neural networks or numerical algorithms. The RMP schemes are demonstrated effectively by the simulation results based on various robotic models; the experiments applying the fundamental RMP scheme to a physical robot manipulator are also presented. As the schemes and the corresponding solvers presented in the book have solved the non-repetitive motion problems existing in redundant robot manipulators, it is of particular use in applying theoretical research based on the quadratic program for redundant robot manipulators in industrial situations. This book will be a valuable reference work for engineers, researchers, advanced undergraduate and graduate students in robotics fields. Yunong Zhang is a professor at The School of Informa...

  5. Detumbling control for kinematically redundant space manipulator post-grasping a rotational satellite

    Science.gov (United States)

    Wang, Mingming; Luo, Jianjun; Yuan, Jianping; Walter, Ulrich

    2017-12-01

    The objective of this paper is to establish a detumbling strategy and a coordination control scheme for a kinematically redundant space manipulator post-grasping a rotational satellite. First, the dynamics of the kinematically redundant space robot after grasping the target is presented, which lays the foundation for the coordination controller design. Subsequently, optimal detumbling and motion planning strategy for the post-capture phase is proposed based on the quartic Bézier curves and adaptive differential evolution (DE) algorithm subject to the specific constraints. Both detumbling time and control torques are taken into account for the generation of the optimal detumbling strategy. Furthermore, a coordination control scheme is presented to track the designed reference path while regulating the attitude of the chaser to a desired value, which successfully dumps the initial angular velocity of the rotational satellite and controls the base attitude synchronously. Simulation results are presented for detumbling a target with rotational motion using a 7 degree-of-freedom (DOF) redundant space manipulator, which demonstrates the effectiveness of the proposed method.

  6. State-space Generalized Predicitve Control for redundant parallel robots

    Czech Academy of Sciences Publication Activity Database

    Belda, Květoslav; Böhm, Josef; Valášek, M.

    2003-01-01

    Roč. 31, č. 3 (2003), s. 413-432 ISSN 1539-7734 R&D Projects: GA ČR GA101/03/0620 Grant - others:CTU(CZ) 0204512 Institutional research plan: CEZ:AV0Z1075907 Keywords : parallel robot construction * generalized predictive control * drive redundancy Subject RIV: BC - Control Systems Theory http://library.utia.cas.cz/separaty/historie/belda-0411126.pdf

  7. Timing control by redundant inhibitory neuronal circuits

    International Nuclear Information System (INIS)

    Tristan, I.; Rulkov, N. F.; Huerta, R.; Rabinovich, M.

    2014-01-01

    Rhythms and timing control of sequential activity in the brain is fundamental to cognition and behavior. Although experimental and theoretical studies support the understanding that neuronal circuits are intrinsically capable of generating different time intervals, the dynamical origin of the phenomenon of functionally dependent timing control is still unclear. Here, we consider a new mechanism that is related to the multi-neuronal cooperative dynamics in inhibitory brain motifs consisting of a few clusters. It is shown that redundancy and diversity of neurons within each cluster enhances the sensitivity of the timing control with the level of neuronal excitation of the whole network. The generality of the mechanism is shown to work on two different neuronal models: a conductance-based model and a map-based model

  8. Timing control by redundant inhibitory neuronal circuits

    Energy Technology Data Exchange (ETDEWEB)

    Tristan, I., E-mail: itristan@ucsd.edu; Rulkov, N. F.; Huerta, R.; Rabinovich, M. [BioCircuits Institute, University of California, San Diego, La Jolla, California 92093-0402 (United States)

    2014-03-15

    Rhythms and timing control of sequential activity in the brain is fundamental to cognition and behavior. Although experimental and theoretical studies support the understanding that neuronal circuits are intrinsically capable of generating different time intervals, the dynamical origin of the phenomenon of functionally dependent timing control is still unclear. Here, we consider a new mechanism that is related to the multi-neuronal cooperative dynamics in inhibitory brain motifs consisting of a few clusters. It is shown that redundancy and diversity of neurons within each cluster enhances the sensitivity of the timing control with the level of neuronal excitation of the whole network. The generality of the mechanism is shown to work on two different neuronal models: a conductance-based model and a map-based model.

  9. WATER SURFACE RECONSTRUCTION IN AIRBORNE LASER BATHYMETRY FROM REDUNDANT BED OBSERVATIONS

    Directory of Open Access Journals (Sweden)

    G. Mandlburger

    2017-09-01

    Full Text Available In airborne laser bathymetry knowledge of exact water level heights is a precondition for applying run-time and refraction correction of the raw laser beam travel path in the medium water. However, due to specular reflection especially at very smooth water surfaces often no echoes from the water surface itself are recorded (drop outs. In this paper, we first discuss the feasibility of reconstructing the water surface from redundant observations of the water bottom in theory. Furthermore, we provide a first practical approach for solving this problem, suitable for static and locally planar water surfaces. It minimizes the bottom surface deviations of point clouds from individual flight strips after refraction correction. Both theoretical estimations and practical results confirm the potential of the presented method to reconstruct water level heights in dm precision. Achieving good results requires enough morphological details in the scene and that the water bottom topography is captured from different directions.

  10. Advantage of redundancy in the controllability of remote handling manipulator

    International Nuclear Information System (INIS)

    Muhammad, Ali; Mattila, Jouni; Vilenius, Matti; Siuko, Mikko; Semeraro, Luigi

    2011-01-01

    To carry out a variety of remote handling operations inside the ITER divertor a Water Hydraulic MANipulator (WHMAN) and its control system have been designed and developed at Tampere University of Technology. The manipulator is installed on top of Cassette Multifunctional Mover (CMM) to assist during the cassette removal and installation operations. While CMM is designed to carry heavy components such as cassettes through the service ducts relying on positioning accuracy and repeatability, WHMAN is designed to execute a mix of remote handling operations using position trajectories and master-slave telemanipulation. WHMAN is composed of eight joints: six rotational and two translational. Since a manipulator requires only six joints to acquire the desired position and orientation in operational-space, the two additional joints of WHMAN provide the redundant degrees of mobility. This paper presents how this redundancy of WHMAN can be an advantage to optimize the execution of remote handling tasks. The paper also discusses an effective way to practically exploit the redundancy. The results show that the additional degrees of freedom can be utilized to improve the dynamic behavior of the manipulator.

  11. Kinematics and control of redundant robotic arm based on dielectric elastomer actuators

    Science.gov (United States)

    Branz, Francesco; Antonello, Andrea; Carron, Andrea; Carli, Ruggero; Francesconi, Alessandro

    2015-04-01

    Soft robotics is a promising field and its application to space mechanisms could represent a breakthrough in space technologies by enabling new operative scenarios (e.g. soft manipulators, capture systems). Dielectric Elastomers Actuators have been under deep study for a number of years and have shown several advantages that could be of key importance for space applications. Among such advantages the most notable are high conversion efficiency, distributed actuation, self-sensing capability, multi-degree-of-freedom design, light weight and low cost. The big potentialities of double cone actuators have been proven in terms of good performances (i.e. stroke and force/torque), ease of manufacturing and durability. In this work the kinematic, dynamic and control design of a two-joint redundant robotic arm is presented. Two double cone actuators are assembled in series to form a two-link design. Each joint has two degrees of freedom (one rotational and one translational) for a total of four. The arm is designed to move in a 2-D environment (i.e. the horizontal plane) with 4 DoF, consequently having two degrees of redundancy. The redundancy is exploited in order to minimize the joint loads. The kinematic design with redundant Jacobian inversion is presented. The selected control algorithm is described along with the results of a number of dynamic simulations that have been executed for performance verification. Finally, an experimental setup is presented based on a flexible structure that counteracts gravity during testing in order to better emulate future zero-gravity applications.

  12. N + 1 redundancy on ATCA instrumentation for Nuclear Fusion

    Energy Technology Data Exchange (ETDEWEB)

    Correia, Miguel, E-mail: miguelfc@ipfn.ist.utl.pt [Associação EURATOM/IST, Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico – Universidade Técnica de Lisboa, Lisboa (Portugal); Sousa, Jorge; Rodrigues, António P.; Batista, António J.N.; Combo, Álvaro; Carvalho, Bernardo B.; Santos, Bruno; Carvalho, Paulo F.; Gonçalves, Bruno [Associação EURATOM/IST, Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico – Universidade Técnica de Lisboa, Lisboa (Portugal); Correia, Carlos M.B.A. [Centro de Instrumentação, Departamento de Física, Universidade de Coimbra, Coimbra (Portugal); Varandas, Carlos A.F. [Associação EURATOM/IST, Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico – Universidade Técnica de Lisboa, Lisboa (Portugal)

    2013-10-15

    Highlights: ► In Nuclear Fusion, demanding security and high-availability requirements call for redundancy to be available. ► ATCA standard features desirable redundancy features for Fusion instrumentation. ► The developed control and data acquisition hardware modules support additional redundancy schemes. ► Implementation of N + 1 redundancy of host processor and I/O data modules. -- Abstract: The role of redundancy on control and data acquisition systems has gained a significant importance in the case of Nuclear Fusion, as demanding security and high-availability requirements call for redundancy to be available. IPFN's control and data acquisition system hardware is based on an Advanced Telecommunications Computing Architecture (ATCA) set of I/O (DAC/ADC endpoints) and data/timing switch modules, which handle data and timing from all I/O endpoints. Modules communicate through Peripheral Component Interconnect Express (PCIe), established over the ATCA backplane and controlled by one or more external hosts. The developed hardware modules were designed to take advantage of ATCA specification's redundancy features, namely at the hardware management level, including support of: (i) multiple host operation with N + 1 redundancy – in which a designated failover host takes over data previously assigned to a suddenly malfunctioning host and (ii) N + 1 redundancy of I/O and data/timing switch modules. This paper briefly describes IPFN's control and data acquisition system, which is being developed for ITER fast plant system controller (FPSC), and analyses the hardware implementation of its supported redundancy features.

  13. Increasing The Dexterity Of Redundant Robots

    Science.gov (United States)

    Seraji, Homayoun

    1990-01-01

    Redundant coordinates used to define additional tasks. Configuration control emerging as effective way to control motions of robot having more degrees of freedom than necessary to define trajectory of end effector and/or of object to be manipulated. Extra or redundant degrees of freedom used to give robot humanlike dexterity and versatility.

  14. The development of radiation hardened tele-robot system - Development of path-planning and control technology for tele-operated redundant manipulator

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Pyung Hun; Park, Ki Cheol; Park, Suk Ho [Korea Advanced Institute of Science and Technology, Taejon (Korea)

    1999-04-01

    This project focuses on the development of the control system for a teleoperated redundant manipulator, which performs many tasks dexterously, while avoiding obstacles, instead of human workers in the extreme situations like nuclear power plants. To this end, four consecutive research works have been performed. First, two new methods for global path-planning have been developed to inspect the global behavior of the redundant manipulator. Second, characteristics of optimal solutions(COS) under inequality constraints have been analyzed and, using the COS, how to greatly enhance the conventional redundancy resolution methods in terms of performance and repeatability has also been proposed. Third, an effective control method for a redundant manipulator has been developed, which incorporates all kinds of physical limits into practical inequality constraints and is computationally efficient for real-time purposes. Finally, using this control method as the controller of the slave redundant manipulator and developing a master manipulator, the inertial torque and gravitation torque of which are negligible, a force-reflected teleoperation control system has been developed. Through the teleoperation control system, human operator can accurately control the position and the force of the end-effector of the slave manipulator while feeling the interaction force between the slave and the workpiece. In addition, the slave redundant manipulator autonomously can control the impedance and can optimize a given performance measure while avoiding physical limits such as joint angle limits and obstacles. 49 refs., 43 figs., 10 tabs. (Author)

  15. Decoupled Sliding Mode Control for a Novel 3-DOF Parallel Manipulator with Actuation Redundancy

    Directory of Open Access Journals (Sweden)

    Niu Xuemei

    2015-05-01

    Full Text Available This paper presents a decoupled nonsingular terminal sliding mode controller (DNTSMC for a novel 3-DOF parallel manipulator with actuation redundancy. According to kinematic analysis, the inverse dynamic model for a novel 3-DOF redundantly actuated parallel manipulator is formulated in the task space using Lagrangian formalism and decoupled into three entirely independent subsystems under generalized coordinates to significantly reduce system complexity. Based on the dynamic model, a decoupled sliding mode control strategy is proposed for the parallel manipulator; the idea behind this strategy is to design a nonsingular terminal sliding mode controller for each subsystem, which can drive states of three subsystems to the original equilibrium points simultaneously by two intermediate variables. Additionally, a RBF neural network is used to compensate the cross-coupling force and gravity to enhance the control precision. Simulation and experimental results show that the proposed DNTSMC can achieve better control performances compared with the conventional sliding mode controller (SMC and the DNTSMC without compensator.

  16. Availability analysis of safety grade multiple redundant controller used in advanced nuclear safety systems

    International Nuclear Information System (INIS)

    Son, Kwang Seop; Kim, Dong Hoon; Park, Gee Yong; Kang, Hyun Gook

    2018-01-01

    Highlights: •The multiple redundant controller, SPLC is configured as the combination of DMR and TMR architecture. •We construct the Markov model of SPLC using the concept of the system unavailability rate. •To satisfy the availability requirement of safety grade controller, the fault coverage factor (FCF) should be ≥0.8 and the MTTR of each module should be ≤100 h when FCF is 0.9. •The availability of SPLC is better than that of PLC having iTMR architecture however it is poorer than iTMR considering the off-line test and inspection on the assumption that MTTR of each module is ≤200 h. -- Abstract: We analyze the availability of the Safety Programmable Logic Controller (SPLC) having multiple redundant architectures. In the SPLC, input/output and processor module are configured as triple modular redundancy (TMR), and backplane bus, power and communication modules are configured as dual modular redundancy (DMR). The voting logics for redundant architectures are based on the forwarding error detection. It means that the receivers perform the voting logics based on the status information of transmitters. To analyze the availability of SPLC, we construct the Markov model and simplify the model adopting the system unavailability rate. The results show that the fault coverage factor should be ≥0.8 and Mean Time To Repair (MTTR) should be ≤100 h in order to satisfy the requirement that the availability of the safety grade PLC should be ≥0.995. Also we evaluate the availability of SPLC comparing to other PLCs such as simplex, processor DMR (pDMR) and independent TMR (iTMR) PLCs used in the existing nuclear safety systems. The availability of SPLC is higher than those of the simplex, pDMR but is lower than that of iTMR for one month which is the periodic off-line test and inspection. That’s why the number of redundant modules used in PLC is more dominant to increasing the availability than the number of fault masking methods such as voting logics used

  17. Redundancy control in music performance : towards an understanding of the role of constraint satisfaction

    NARCIS (Netherlands)

    Heijink, H.J.I.C.M.

    2002-01-01

    We investigated two redundancy control problems related to music performance, one in computer science and one in motor control research, viz., score-performance matching and guitar fingering. In score-performance matching, a score and a performance have to be compared note by note to find the

  18. Control Systems for Hyper-Redundant Robots Based on Artificial Potential Method

    Directory of Open Access Journals (Sweden)

    Mihaela Florescu

    2015-06-01

    Full Text Available This paper presents the control method of hyper-redundant robots based on the artificial potential approach. The principles of this method are shown and a suggestive example is offered. Then, the artificial potential method is applied to the case of a tentacle robot starting from the dynamic model of the robot. In addition, a series of results that are obtained through simulation is presented.

  19. An analytical and experimental study of the behaviour of redundant controllers applied to a nuclear plant

    International Nuclear Information System (INIS)

    Lawrence, L.A.J.

    1964-02-01

    The behaviour of a number of configurations of redundant controllers is examined and the design problems discussed in relation to the engineering of reliable control rod drive systems for nuclear plant. (author)

  20. Multi-finger prehension: control of a redundant mechanical system.

    Science.gov (United States)

    Latash, Mark L; Zatsiorsky, Vladimir M

    2009-01-01

    The human hand has been a fascinating object of study for researchers in both biomechanics and motor control. Studies of human prehension have contributed significantly to the progress in addressing the famous problem of motor redundancy. After a brief review of the hand mechanics, we present results of recent studies that support a general view that the apparently redundant design of the hand is not a source of computational problems but a rich apparatus that allows performing a variety of tasks in a reliable and flexible way (the principle of abundance). Multi-digit synergies have been analyzed at two levels of a hypothetical hierarchy involved in the control of prehensile actions. At the upper level, forces and moments produced by the thumb and virtual finger (an imagined finger with a mechanical action equal to the combined mechanical action of all four fingers of the hand) co-vary to stabilize the gripping action and the orientation of the hand-held object. These results support the principle of superposition suggested earlier in robotics with respect to the control of artificial grippers. At the lower level of the hierarchy, forces and moments produced by individual fingers co-vary to stabilize the magnitude and direction of the force vector and the moment of force produced by the virtual finger. Adjustments to changes in task constraints (such as, for example, friction under individual digits) may be local and synergic. The latter reflect multi-digit prehension synergies and may be analyzed with the so-called chain effects: Sequences of relatively straightforward cause-effect links directly related to mechanical constraints leading to non-trivial strong co-variation between pairs of elemental variables. Analysis of grip force adjustments during motion of hand-held objects suggests that the central nervous system adjusts to gravitational and inertial loads differently. The human hand is a gold mine for researchers interested in the control of natural human

  1. Commercialization of JPL Virtual Reality calibration and redundant manipulator control technologies

    Science.gov (United States)

    Kim, Won S.; Seraji, Homayoun; Fiorini, Paolo; Brown, Robert; Christensen, Brian; Beale, Chris; Karlen, James; Eismann, Paul

    1994-01-01

    Within NASA's recent thrust for industrial collaboration, JPL (Jet Propulsion Laboratory) has recently established two technology cooperation agreements in the robotics area: one on virtual reality (VR) calibration with Deneb Robotics, Inc., and the other on redundant manipulator control with Robotics Research Corporation (RRC). These technology transfer cooperation tasks will enable both Deneb and RRC to commercialize enhanced versions of their products that will greatly benefit both space and terrestrial telerobotic applications.

  2. Control system developments for a range of kinematically redundant hydraulic manipulators

    International Nuclear Information System (INIS)

    Smith, A.L.; Rice, P.S.; Thiruarooran, C.

    2000-01-01

    This paper describes a range of control system improvements developed and implemented for in-reactor use during the last three years. Novel control techniques have been developed to provide accurate closed-loop velocity control of pumped hydraulic manipulator joints under a wide range of operating conditions. As a result the supervisory computer system can provide accurate trajectory following, even when more than ten joints are required to move simultaneously. Accurately coordinated motion has given rise to some spectacular gains in in-reactor performance in terms of deployment time, safety and accessibility. The same low-level control improvements have made it feasible to integrate and use the 'geometric controller' to provide accurate resolved motion control of a kinematically redundant manipulator. Examples of recent in-reactor use of all these techniques are given. (author)

  3. Modeling of the dynamics of GBB1005 Ball & Beam Educational Control System as a controlled mechanical system with a redundant coordinate

    Directory of Open Access Journals (Sweden)

    A. Ya. Krasinskii

    2014-01-01

    Full Text Available The method of research stability and stabilization of equilibrium of systems with geometrical constraints is elaborated and used for equilibrium for real mechatronic arrangement GBB1005 Ball & Beam. For mathematical model construction is used Shul'gin's equations with redundant coordinates. The through differentiation geometrical constraints obtained kinematic (holonomic constraints is necessary add for stability analysis. Asymptotic stability equilibrium for mechanical systems with redundant coordinates is possible , in spite of formal reduction to Lyapunov's especial case, if the number zero roots is equal the number constraints . More exact nonlinear mathematical model of the mechanical component Ball &Beam is considered in this paper. One nonlinear geometric constrain in this problem is allow find the new equilibrium position. The choice of linear control subsystem is depend from the choice of redundant coordinate.

  4. ANALYSIS OF RELIABILITY OF THE PERIODICALLY AND CONTINUOUSLY CONTROLLED QUEUING SYSTEM WITH TIME REDUNDANCY

    International Nuclear Information System (INIS)

    Mikadze, I.; Namchevadze, T.; Gobiani, I.

    2007-01-01

    There is proposed a generalized mathematical model of the queuing system with time redundancy without preliminary checking of the queuing system at transition from the free state into the engaged one. The model accounts for various failures of the queuing system detected by continuous instrument control, periodic control, control during recovery and the failures revealed immediately after accumulation of a certain number of failures. The generating function of queue length in both stationary and nonstationary modes was determined. (author)

  5. Reliability–redundancy allocation problem considering optimal redundancy strategy using parallel genetic algorithm

    International Nuclear Information System (INIS)

    Kim, Heungseob; Kim, Pansoo

    2017-01-01

    To maximize the reliability of a system, the traditional reliability–redundancy allocation problem (RRAP) determines the component reliability and level of redundancy for each subsystem. This paper proposes an advanced RRAP that also considers the optimal redundancy strategy, either active or cold standby. In addition, new examples are presented for it. Furthermore, the exact reliability function for a cold standby redundant subsystem with an imperfect detector/switch is suggested, and is expected to replace the previous approximating model that has been used in most related studies. A parallel genetic algorithm for solving the RRAP as a mixed-integer nonlinear programming model is presented, and its performance is compared with those of previous studies by using numerical examples on three benchmark problems. - Highlights: • Optimal strategy is proposed to solve reliability redundancy allocation problem. • The redundancy strategy uses parallel genetic algorithm. • Improved reliability function for a cold standby subsystem is suggested. • Proposed redundancy strategy enhances the system reliability.

  6. Redundant control of migration and adhesion by ERM proteins in vascular smooth muscle cells

    International Nuclear Information System (INIS)

    Baeyens, Nicolas; Latrache, Iman; Yerna, Xavier; Noppe, Gauthier; Horman, Sandrine; Morel, Nicole

    2013-01-01

    Highlights: •The three ERM proteins are expressed in vascular smooth muscle cell. •ERM depletion inhibited PDGF-evoked migration redundantly. •ERM depletion increased cell adhesion redundantly. •ERM depletion did not affect PDGF-evoked Ca signal, Rac1 activation, proliferation. •ERM proteins control PDGF-induced migration by regulating adhesion. -- Abstract: Ezrin, radixin, and moesin possess a very similar structure with a C-terminal actin-binding domain and a N-terminal FERM interacting domain. They are known to be involved in cytoskeleton organization in several cell types but their function in vascular smooth muscle cells (VSMC) is still unknown. The aim of this study was to investigate the role of ERM proteins in cell migration induced by PDGF, a growth factor involved in pathophysiological processes like angiogenesis or atherosclerosis. We used primary cultured VSMC obtained from rat aorta, which express the three ERM proteins. Simultaneous depletion of the three ERM proteins with specific siRNAs abolished the effects of PDGF on cell architecture and migration and markedly increased cell adhesion and focal adhesion size, while these parameters were only slightly affected by depletion of ezrin, radixin or moesin alone. Rac1 activation, cell proliferation, and Ca 2+ signal in response to PDGF were unaffected by ERM depletion. These results indicate that ERM proteins exert a redundant control on PDGF-induced VSMC migration by regulating focal adhesion turn-over and cell adhesion to substrate

  7. Redundant control of migration and adhesion by ERM proteins in vascular smooth muscle cells

    Energy Technology Data Exchange (ETDEWEB)

    Baeyens, Nicolas; Latrache, Iman; Yerna, Xavier [Laboratory of Cell Physiology, IoNS, Université Catholique de Louvain (Belgium); Noppe, Gauthier; Horman, Sandrine [Pôle de Recherche Cardiovasculaire, IREC, Université Catholique de Louvain (Belgium); Morel, Nicole, E-mail: nicole.morel@uclouvain.be [Laboratory of Cell Physiology, IoNS, Université Catholique de Louvain (Belgium)

    2013-11-22

    Highlights: •The three ERM proteins are expressed in vascular smooth muscle cell. •ERM depletion inhibited PDGF-evoked migration redundantly. •ERM depletion increased cell adhesion redundantly. •ERM depletion did not affect PDGF-evoked Ca signal, Rac1 activation, proliferation. •ERM proteins control PDGF-induced migration by regulating adhesion. -- Abstract: Ezrin, radixin, and moesin possess a very similar structure with a C-terminal actin-binding domain and a N-terminal FERM interacting domain. They are known to be involved in cytoskeleton organization in several cell types but their function in vascular smooth muscle cells (VSMC) is still unknown. The aim of this study was to investigate the role of ERM proteins in cell migration induced by PDGF, a growth factor involved in pathophysiological processes like angiogenesis or atherosclerosis. We used primary cultured VSMC obtained from rat aorta, which express the three ERM proteins. Simultaneous depletion of the three ERM proteins with specific siRNAs abolished the effects of PDGF on cell architecture and migration and markedly increased cell adhesion and focal adhesion size, while these parameters were only slightly affected by depletion of ezrin, radixin or moesin alone. Rac1 activation, cell proliferation, and Ca{sup 2+} signal in response to PDGF were unaffected by ERM depletion. These results indicate that ERM proteins exert a redundant control on PDGF-induced VSMC migration by regulating focal adhesion turn-over and cell adhesion to substrate.

  8. Ethernet redundancy

    Energy Technology Data Exchange (ETDEWEB)

    Burak, K. [Invensys Process Systems, M/S C42-2B, 33 Commercial Street, Foxboro, MA 02035 (United States)

    2006-07-01

    We describe the Ethernet systems and their evolution: LAN Segmentation, DUAL networks, network loops, network redundancy and redundant network access. Ethernet (IEEE 802.3) is an open standard with no licensing fees and its specifications are freely available. As a result, it is the most popular data link protocol in use. It is important that the network be redundant and standard Ethernet protocols like RSTP (IEEE 802.1w) provide the fast network fault detection and recovery times that is required today. As Ethernet does continue to evolve, network redundancy is and will be a mixture of technology standards. So it is very important that both end-stations and networking devices be Ethernet (IEEE 802.3) compliant. Then when new technologies, such as the IEEE 802.1aq Shortest Path Bridging protocol, come to market they can be easily deployed in the network without worry.

  9. Ethernet redundancy

    International Nuclear Information System (INIS)

    Burak, K.

    2006-01-01

    We describe the Ethernet systems and their evolution: LAN Segmentation, DUAL networks, network loops, network redundancy and redundant network access. Ethernet (IEEE 802.3) is an open standard with no licensing fees and its specifications are freely available. As a result, it is the most popular data link protocol in use. It is important that the network be redundant and standard Ethernet protocols like RSTP (IEEE 802.1w) provide the fast network fault detection and recovery times that is required today. As Ethernet does continue to evolve, network redundancy is and will be a mixture of technology standards. So it is very important that both end-stations and networking devices be Ethernet (IEEE 802.3) compliant. Then when new technologies, such as the IEEE 802.1aq Shortest Path Bridging protocol, come to market they can be easily deployed in the network without worry

  10. Redundant and fault-tolerant algorithms for real-time measurement and control systems for weapon equipment.

    Science.gov (United States)

    Li, Dan; Hu, Xiaoguang

    2017-03-01

    Because of the high availability requirements from weapon equipment, an in-depth study has been conducted on the real-time fault-tolerance of the widely applied Compact PCI (CPCI) bus measurement and control system. A redundancy design method that uses heartbeat detection to connect the primary and alternate devices has been developed. To address the low successful execution rate and relatively large waste of time slices in the primary version of the task software, an improved algorithm for real-time fault-tolerant scheduling is proposed based on the Basic Checking available time Elimination idle time (BCE) algorithm, applying a single-neuron self-adaptive proportion sum differential (PSD) controller. The experimental validation results indicate that this system has excellent redundancy and fault-tolerance, and the newly developed method can effectively improve the system availability. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  11. Redundancy control in music performance : towards an understanding of the role of constraint satisfaction

    OpenAIRE

    Heijink, H.J.I.C.M.

    2002-01-01

    We investigated two redundancy control problems related to music performance, one in computer science and one in motor control research, viz., score-performance matching and guitar fingering. In score-performance matching, a score and a performance have to be compared note by note to find the optimal correspondence between the two. There are exponentially many possible correspondences, but we found that a general algorithmic technique that uses structural information in the score performs wel...

  12. The Development of Synchronization Function for Triple Redundancy System Based on SCADE

    Directory of Open Access Journals (Sweden)

    Moupeng

    2015-07-01

    Full Text Available Redundancy technique is an effective approach to improve the reliability and security of flight control system, synchronization function of redundancy system is the key technology of redundancy management. The flight control computer synchronization model is developed by graphical modeling method in the SCADE development environment, the automatic code generation technology is used to generate high level reliable embedded real-time code for synchronization function, omitting the code test process, shorten the development cycle. In the practical application, the program can accomplish the functional synchronization, and lay a well foundation for the redundancy system.

  13. Maximization of learning speed in the motor cortex due to neuronal redundancy.

    Directory of Open Access Journals (Sweden)

    Ken Takiyama

    2012-01-01

    Full Text Available Many redundancies play functional roles in motor control and motor learning. For example, kinematic and muscle redundancies contribute to stabilizing posture and impedance control, respectively. Another redundancy is the number of neurons themselves; there are overwhelmingly more neurons than muscles, and many combinations of neural activation can generate identical muscle activity. The functional roles of this neuronal redundancy remains unknown. Analysis of a redundant neural network model makes it possible to investigate these functional roles while varying the number of model neurons and holding constant the number of output units. Our analysis reveals that learning speed reaches its maximum value if and only if the model includes sufficient neuronal redundancy. This analytical result does not depend on whether the distribution of the preferred direction is uniform or a skewed bimodal, both of which have been reported in neurophysiological studies. Neuronal redundancy maximizes learning speed, even if the neural network model includes recurrent connections, a nonlinear activation function, or nonlinear muscle units. Furthermore, our results do not rely on the shape of the generalization function. The results of this study suggest that one of the functional roles of neuronal redundancy is to maximize learning speed.

  14. Determination and compensation of the “reference surface” from redundant sets of surface measurements

    Energy Technology Data Exchange (ETDEWEB)

    Polack, François, E-mail: francois.polack@synchrotron-soleil.fr [Synchrotron SOLEIL, L' Orme des Merisiers, Saint-Aubin, BP48, 91192 Gif-sur-Yvette Cedex (France); Thomasset, Muriel, E-mail: muriel.thomasset@synchrotron-soleil.fr [Synchrotron SOLEIL, L' Orme des Merisiers, Saint-Aubin, BP48, 91192 Gif-sur-Yvette Cedex (France)

    2013-05-11

    When trying to measure an optical surface at utmost absolute precision, the problem of the missing or unknown “reference surface” is often encountered. It is obvious with Fizeau and Michelson's interferometry, where the height difference between the surface under test (SUT) and a reference surface is measured. It is also true from slope measurements in long trace profilers (LTP), where due to small construction errors, the response to a perfectly flat ideal surface can be considered as an unknown reference to be subtracted from the measurement data. As no “perfect artifact” can exist, these references cannot be directly determined. The addition of the unknown reference can severely bias the reconstructed surface when field stitching is applied. The results of ptychography have proved that when a measurement is a function of a unique object function with a translated but unique response function, the redundancy of a large set of data allows accurate reconstructions of the object and response function despite the presence of measurement noise. In the case of LTP and interferometry, the basic problem is linear and can be solved by linear algebra rather than iteratively. The method has been already applied to SOLEIL and ESRF LTPs and is succesfully used on a regular base. We show here that the method can be also applied to interferometry and improve stitching results.

  15. Modeling and Control of the Redundant Parallel Adjustment Mechanism on a Deployable Antenna Panel

    Directory of Open Access Journals (Sweden)

    Lili Tian

    2016-10-01

    Full Text Available With the aim of developing multiple input and multiple output (MIMO coupling systems with a redundant parallel adjustment mechanism on the deployable antenna panel, a structural control integrated design methodology is proposed in this paper. Firstly, the modal information from the finite element model of the structure of the antenna panel is extracted, and then the mathematical model is established with the Hamilton principle; Secondly, the discrete Linear Quadratic Regulator (LQR controller is added to the model in order to control the actuators and adjust the shape of the panel. Finally, the engineering practicality of the modeling and control method based on finite element analysis simulation is verified.

  16. Inverse kinematics of redundant systems driver IKORv1.0-2.0 (full space parameterization with orientation control, platform mobility, and portability)

    Energy Technology Data Exchange (ETDEWEB)

    Hacker, C.J.; Fries, G.A.; Pin, F.G.

    1997-01-01

    Few optimization methods exist for path planning of kinematically redundant manipulators. Among these, a universal method is lacking that takes advantage of a manipulator`s redundancy while satisfying possibly varying constraints and task requirements. Full Space Parameterization (FSP) is a new method that generates the entire solution space of underspecified systems of algebraic equations and then calculates the unique solution satisfying specific constraints and optimization criteria. The FSP method has been previously tested on several configurations of the redundant manipulator HERMIES-III. This report deals with the extension of the FSP driver, Inverse Kinematics On Redundant systems (IKOR), to include three-dimensional manipulation systems, possibly incorporating a mobile platform, with and without orientation control. The driver was also extended by integrating two optimized versions of the FSP solution generator as well as the ability to easily port to any manipulator. IKOR was first altered to include the ability to handle orientation control and to integrate an optimized solution generator. The resulting system was tested on a 4 degrees-of-redundancy manipulator arm and was found to successfully perform trajectories with least norm criteria while avoiding obstacles and joint limits. Next, the system was adapted and tested on a manipulator arm placed on a mobile platform yielding 7 degrees of redundancy. After successful testing on least norm trajectories while avoiding obstacles and joint limits, IKORv1.0 was developed. The system was successfully verified using comparisons with a current industry standard, the Moore Penrose Pseudo-Inverse. Finally, IKORv2.0 was created, which includes both the one shot and two step methods, manipulator portability, integration of a second optimized solution generator, and finally a more robust and usable code design.

  17. Virtual Modular Redundancy of Processor Module in the PLC

    International Nuclear Information System (INIS)

    Lee, Kwang-Il; Hwang, SungJae; Yoon, DongHwa

    2016-01-01

    Dual Modular Redundancy (DMR) is mainly used to implement these safety control systems. DMR is conveyed when components of a system are duplicated, providing another component in case one should fault or fail. This feature has a high availability and large fault tolerant. It provides zero downtime that is required for nuclear power plants. So nuclear power plant has been commercialized by multiple redundant systems. The following paper, we propose a Virtual Modular Redundancy (VMR) rather than physical triple of the Programmable Logic Controller (PLC) processor module to ensure the reliability of the nuclear power plant control system. VMR implementation minimizes design changes to continue to use the commercially available redundant system. Also, the purpose of the VMR is to improve the efficiency and reliability in many ways, such as fault tolerant and fail-safe and cost. VMR guarantees a wide range of reliable fault recovery, fault tolerance, etc. It is prevented before it causes great damages due to the continuous failure of the two modules. The reliable communication speed is slow and also it has a small bandwidth. It is a great loss in the safety control system. However, VMR aims to avoid nuclear power plants that were suspended due to fail-safe. It is not for the purpose of commonly used. Application of VMR is actually expected to require a lot of research and trial and error until they adapt to the nuclear regulatory and standards

  18. Virtual Modular Redundancy of Processor Module in the PLC

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kwang-Il; Hwang, SungJae; Yoon, DongHwa [SOOSAN ENS Co., Seoul (Korea, Republic of)

    2016-10-15

    Dual Modular Redundancy (DMR) is mainly used to implement these safety control systems. DMR is conveyed when components of a system are duplicated, providing another component in case one should fault or fail. This feature has a high availability and large fault tolerant. It provides zero downtime that is required for nuclear power plants. So nuclear power plant has been commercialized by multiple redundant systems. The following paper, we propose a Virtual Modular Redundancy (VMR) rather than physical triple of the Programmable Logic Controller (PLC) processor module to ensure the reliability of the nuclear power plant control system. VMR implementation minimizes design changes to continue to use the commercially available redundant system. Also, the purpose of the VMR is to improve the efficiency and reliability in many ways, such as fault tolerant and fail-safe and cost. VMR guarantees a wide range of reliable fault recovery, fault tolerance, etc. It is prevented before it causes great damages due to the continuous failure of the two modules. The reliable communication speed is slow and also it has a small bandwidth. It is a great loss in the safety control system. However, VMR aims to avoid nuclear power plants that were suspended due to fail-safe. It is not for the purpose of commonly used. Application of VMR is actually expected to require a lot of research and trial and error until they adapt to the nuclear regulatory and standards.

  19. Design and Sensor-Based Control for Hyper-Redundant Mechanisms

    International Nuclear Information System (INIS)

    Choset, Howie

    2002-01-01

    Toxic materials in DOE sites pose a significant threat to DOE personnel who must inspect these locations. Working in confined spaces further complicates the situation especially when the workers must wear heavy and cumbersome protective suits. A robot or conventional mechanism can clearly bypass the danger and perhaps expedite the characterization process because the person is removed from the site and neither the site nor the person require preparation. However, conventional robots are not suitable for these inspection tasks because they are not flexible enough to pass through and into target DOE inspection sites. This effort is developing an articulated probe, called a hyper redundant mechanism, which is a snake-like device that can exploit its many internal degrees of freedom to thread through tightly packed volumes transmitting images and data from remote locations inaccessible to conventional robots and people. This effort contains two parts: mechanism development and control of the device

  20. Design and Sensor-Based Control for Hyper-Redundant Mechanisms

    International Nuclear Information System (INIS)

    Choset, Howie

    2003-01-01

    Toxic materials in DOE sites pose a significant threat to DOE personnel who must inspect these locations. Working in confined spaces further complicates the situation especially when the workers must wear heavy and cumbersome protective suits. A robot or conventional mechanism can clearly bypass the danger and perhaps expedite the characterization process because the person is removed from the site and neither the site nor the person require preparation. However, conventional robots are not suitable for these inspection tasks because they are not flexible enough to pass through and into target DOE inspection sites. This effort is developing an articulated probe, called a hyper redundant mechanism, which is a snake-like device that can exploit its many internal degrees of freedom to thread through tightly packed volumes transmitting images and data from remote locations inaccessible to conventional robots and people. This effort contains two parts: mechanism development and control of the device

  1. How Redundant Are Redundant Color Adjectives? An Efficiency-Based Analysis of Color Overspecification

    OpenAIRE

    Rubio-Fern?ndez, Paula

    2016-01-01

    Color adjectives tend to be used redundantly in referential communication. I propose that redundant color adjectives are often intended to exploit a color contrast in the visual context and hence facilitate object identification, despite not being necessary to establish unique reference. Two language-production experiments investigated two types of factors that may affect the use of redundant color adjectives: factors related to the efficiency of color in the visual context and factors relate...

  2. Compliant behaviour of redundant robot arm - experiments with null-space

    Directory of Open Access Journals (Sweden)

    Petrović Petar B.

    2015-01-01

    Full Text Available This paper presents theoretical and experimental aspects of Jacobian nullspace use in kinematically redundant robots for achieving kinetostatically consistent control of their compliant behavior. When the stiffness of the robot endpoint is dominantly influenced by the compliance of the robot joints, generalized stiffness matrix can be mapped into joint space using appropriate congruent transformation. Actuation stiffness matrix achieved by this transformation is generally nondiagonal. Off-diagonal elements of the actuation matrix can be generated by redundant actuation only (polyarticular actuators, but such kind of actuation is very difficult to realize practically in technical systems. The approach of solving this problem which is proposed in this paper is based on the use of kinematic redundancy and nullspace of the Jacobian matrix. Evaluation of the developed analytical model was done numerically by a minimal redundant robot with one redundant d.o.f. and experimentally by a 7 d.o.f. Yaskawa SIA 10F robot arm. [Projekat Ministarstva nauke Republike Srbije, br. TR35007

  3. Redundancy control in pathway databases (ReCiPa): an application for improving gene-set enrichment analysis in Omics studies and "Big data" biology.

    Science.gov (United States)

    Vivar, Juan C; Pemu, Priscilla; McPherson, Ruth; Ghosh, Sujoy

    2013-08-01

    Abstract Unparalleled technological advances have fueled an explosive growth in the scope and scale of biological data and have propelled life sciences into the realm of "Big Data" that cannot be managed or analyzed by conventional approaches. Big Data in the life sciences are driven primarily via a diverse collection of 'omics'-based technologies, including genomics, proteomics, metabolomics, transcriptomics, metagenomics, and lipidomics. Gene-set enrichment analysis is a powerful approach for interrogating large 'omics' datasets, leading to the identification of biological mechanisms associated with observed outcomes. While several factors influence the results from such analysis, the impact from the contents of pathway databases is often under-appreciated. Pathway databases often contain variously named pathways that overlap with one another to varying degrees. Ignoring such redundancies during pathway analysis can lead to the designation of several pathways as being significant due to high content-similarity, rather than truly independent biological mechanisms. Statistically, such dependencies also result in correlated p values and overdispersion, leading to biased results. We investigated the level of redundancies in multiple pathway databases and observed large discrepancies in the nature and extent of pathway overlap. This prompted us to develop the application, ReCiPa (Redundancy Control in Pathway Databases), to control redundancies in pathway databases based on user-defined thresholds. Analysis of genomic and genetic datasets, using ReCiPa-generated overlap-controlled versions of KEGG and Reactome pathways, led to a reduction in redundancy among the top-scoring gene-sets and allowed for the inclusion of additional gene-sets representing possibly novel biological mechanisms. Using obesity as an example, bioinformatic analysis further demonstrated that gene-sets identified from overlap-controlled pathway databases show stronger evidence of prior association

  4. Redundant Sb condensation on GaSb epilayers grown by molecular beam epitaxy during cooling procedure

    International Nuclear Information System (INIS)

    Arpapay, B.; Şahin, S.; Arıkan, B.; Serincan, U.

    2014-01-01

    The effect of four different cooling receipts on the surface morphologies of unintentionally-doped GaSb epilayers on GaSb (100) substrates grown by molecular beam epitaxy is reported. Those receipts include three different Sb beam equivalent pressure (BEP) levels and two different termination temperatures. Surface morphologies of epilayers were examined by wet etching, surface profiler, atomic force microscopy, scanning electron microscopy and Raman spectroscopy. The results demonstrate that during the cooling period, a Sb BEP of 4.00 × 10 −4 Pa at a termination temperature of 400 °C induces a smooth surface without Sb condensation whereas same Sb BEP at a termination temperature of 350 °C forms a 300 nm thick Sb layer on the surface. In addition, it is revealed that by applying a wet etching procedure and using a surface profiler it is possible to identify this condensed layer from the two-sloped feature of mesa profile. - Highlights: • Sb beam flux termination temperature is crucial for redundant Sb condensation. • Sb beam flux level has a role on the thickness of redundant condensed Sb layer. • Redundant Sb layer thickness can be measured by two-sloped mesa structure

  5. REDUNDANT ARRAY CONFIGURATIONS FOR 21 cm COSMOLOGY

    Energy Technology Data Exchange (ETDEWEB)

    Dillon, Joshua S.; Parsons, Aaron R., E-mail: jsdillon@berkeley.edu [Department of Astronomy, UC Berkeley, Berkeley, CA (United States)

    2016-08-01

    Realizing the potential of 21 cm tomography to statistically probe the intergalactic medium before and during the Epoch of Reionization requires large telescopes and precise control of systematics. Next-generation telescopes are now being designed and built to meet these challenges, drawing lessons from first-generation experiments that showed the benefits of densely packed, highly redundant arrays—in which the same mode on the sky is sampled by many antenna pairs—for achieving high sensitivity, precise calibration, and robust foreground mitigation. In this work, we focus on the Hydrogen Epoch of Reionization Array (HERA) as an interferometer with a dense, redundant core designed following these lessons to be optimized for 21 cm cosmology. We show how modestly supplementing or modifying a compact design like HERA’s can still deliver high sensitivity while enhancing strategies for calibration and foreground mitigation. In particular, we compare the imaging capability of several array configurations, both instantaneously (to address instrumental and ionospheric effects) and with rotation synthesis (for foreground removal). We also examine the effects that configuration has on calibratability using instantaneous redundancy. We find that improved imaging with sub-aperture sampling via “off-grid” antennas and increased angular resolution via far-flung “outrigger” antennas is possible with a redundantly calibratable array configuration.

  6. Quantifying Net Synergy/Redundancy of Spontaneous Variability Regulation via Predictability and Transfer Entropy Decomposition Frameworks.

    Science.gov (United States)

    Porta, Alberto; Bari, Vlasta; De Maria, Beatrice; Takahashi, Anielle C M; Guzzetti, Stefano; Colombo, Riccardo; Catai, Aparecida M; Raimondi, Ferdinando; Faes, Luca

    2017-11-01

    Objective: Indexes assessing the balance between redundancy and synergy were hypothesized to be helpful in characterizing cardiovascular control from spontaneous beat-to-beat variations of heart period (HP), systolic arterial pressure (SAP), and respiration (R). Methods: Net redundancy/synergy indexes were derived according to predictability and transfer entropy decomposition strategies via a multivariate linear regression approach. Indexes were tested in two protocols inducing modifications of the cardiovascular regulation via baroreflex loading/unloading (i.e., head-down tilt at -25° and graded head-up tilt at 15°, 30°, 45°, 60°, 75°, and 90°, respectively). The net redundancy/synergy of SAP and R to HP and of HP and R to SAP were estimated over stationary sequences of 256 successive values. Results: We found that: 1) regardless of the target (i.e., HP or SAP) redundancy was prevalent over synergy and this prevalence was independent of type and magnitude of the baroreflex challenge; 2) the prevalence of redundancy disappeared when decoupling inputs from output via a surrogate approach; 3) net redundancy was under autonomic control given that it varied in proportion to the vagal withdrawal during graded head-up tilt; and 4) conclusions held regardless of the decomposition strategy. Conclusion: Net redundancy indexes can monitor changes of cardiovascular control from a perspective completely different from that provided by more traditional univariate and multivariate methods. Significance: Net redundancy measures might provide a practical tool to quantify the reservoir of effective cardiovascular regulatory mechanisms sharing causal influences over a target variable. Objective: Indexes assessing the balance between redundancy and synergy were hypothesized to be helpful in characterizing cardiovascular control from spontaneous beat-to-beat variations of heart period (HP), systolic arterial pressure (SAP), and respiration (R). Methods: Net redundancy

  7. Design structure for in-system redundant array repair in integrated circuits

    Science.gov (United States)

    Bright, Arthur A.; Crumley, Paul G.; Dombrowa, Marc; Douskey, Steven M.; Haring, Rudolf A.; Oakland, Steven F.; Quellette, Michael R.; Strissel, Scott A.

    2008-11-25

    A design structure for repairing an integrated circuit during operation of the integrated circuit. The integrated circuit comprising of a multitude of memory arrays and a fuse box holding control data for controlling redundancy logic of the arrays. The design structure provides the integrated circuit with a control data selector for passing the control data from the fuse box to the memory arrays; providing a source of alternate control data, external of the integrated circuit; and connecting the source of alternate control data to the control data selector. The design structure further passes the alternate control data from the source thereof, through the control data selector and to the memory arrays to control the redundancy logic of the memory arrays.

  8. The bliss (not the problem) of motor abundance (not redundancy).

    Science.gov (United States)

    Latash, Mark L

    2012-03-01

    Motor control is an area of natural science exploring how the nervous system interacts with other body parts and the environment to produce purposeful, coordinated actions. A central problem of motor control-the problem of motor redundancy-was formulated by Nikolai Bernstein as the problem of elimination of redundant degrees-of-freedom. Traditionally, this problem has been addressed using optimization methods based on a variety of cost functions. This review draws attention to a body of recent findings suggesting that the problem has been formulated incorrectly. An alternative view has been suggested as the principle of abundance, which considers the apparently redundant degrees-of-freedom as useful and even vital for many aspects of motor behavior. Over the past 10 years, dozens of publications have provided support for this view based on the ideas of synergic control, computational apparatus of the uncontrolled manifold hypothesis, and the equilibrium-point (referent configuration) hypothesis. In particular, large amounts of "good variance"-variance in the space of elements that has no effect on the overall performance-have been documented across a variety of natural actions. "Good variance" helps an abundant system to deal with secondary tasks and unexpected perturbations; its amount shows adaptive modulation across a variety of conditions. These data support the view that there is no problem of motor redundancy; there is bliss of motor abundance.

  9. An efficient simulated annealing algorithm for the redundancy allocation problem with a choice of redundancy strategies

    International Nuclear Information System (INIS)

    Chambari, Amirhossain; Najafi, Amir Abbas; Rahmati, Seyed Habib A.; Karimi, Aida

    2013-01-01

    The redundancy allocation problem (RAP) is an important reliability optimization problem. This paper studies a specific RAP in which redundancy strategies are chosen. To do so, the choice of the redundancy strategies among active and cold standby is considered as decision variables. The goal is to select the redundancy strategy, component, and redundancy level for each subsystem such that the system reliability is maximized. Since RAP is a NP-hard problem, we propose an efficient simulated annealing algorithm (SA) to solve it. In addition, to evaluating the performance of the proposed algorithm, it is compared with well-known algorithms in the literature for different test problems. The results of the performance analysis show a relatively satisfactory efficiency of the proposed SA algorithm

  10. Exploration of joint redundancy but not task space variability facilitates supervised motor learning.

    Science.gov (United States)

    Singh, Puneet; Jana, Sumitash; Ghosal, Ashitava; Murthy, Aditya

    2016-12-13

    The number of joints and muscles in a human arm is more than what is required for reaching to a desired point in 3D space. Although previous studies have emphasized how such redundancy and the associated flexibility may play an important role in path planning, control of noise, and optimization of motion, whether and how redundancy might promote motor learning has not been investigated. In this work, we quantify redundancy space and investigate its significance and effect on motor learning. We propose that a larger redundancy space leads to faster learning across subjects. We observed this pattern in subjects learning novel kinematics (visuomotor adaptation) and dynamics (force-field adaptation). Interestingly, we also observed differences in the redundancy space between the dominant hand and nondominant hand that explained differences in the learning of dynamics. Taken together, these results provide support for the hypothesis that redundancy aids in motor learning and that the redundant component of motor variability is not noise.

  11. Redundancy of Redundancy in Justifications of Verdicts of Polish The Constitutional Tribuna

    Directory of Open Access Journals (Sweden)

    Jan Winczorek

    2016-09-01

    Full Text Available The results of an empirical study of 150 justifications of verdicts of the Polish Constitutional Tribunal (CT are discussed. CT justifies its decisions mostly on authoritative references to previous decisions and other doxa- type arguments. It thus does not convince the audience of a decision's validity, but rather documents it. Further, the methodology changes depending on features of the case. The results are analysed using a conceptual    framework    of sociological systems theory. It is shown that CT's justification methodology ignores the redundancy (excess of references and dependencies of the legal system, finding redundancy redundant. This is a risky strategy of decision- making, enabling political influence.

  12. Predicting genome-wide redundancy using machine learning

    Directory of Open Access Journals (Sweden)

    Shasha Dennis E

    2010-11-01

    Full Text Available Abstract Background Gene duplication can lead to genetic redundancy, which masks the function of mutated genes in genetic analyses. Methods to increase sensitivity in identifying genetic redundancy can improve the efficiency of reverse genetics and lend insights into the evolutionary outcomes of gene duplication. Machine learning techniques are well suited to classifying gene family members into redundant and non-redundant gene pairs in model species where sufficient genetic and genomic data is available, such as Arabidopsis thaliana, the test case used here. Results Machine learning techniques that combine multiple attributes led to a dramatic improvement in predicting genetic redundancy over single trait classifiers alone, such as BLAST E-values or expression correlation. In withholding analysis, one of the methods used here, Support Vector Machines, was two-fold more precise than single attribute classifiers, reaching a level where the majority of redundant calls were correctly labeled. Using this higher confidence in identifying redundancy, machine learning predicts that about half of all genes in Arabidopsis showed the signature of predicted redundancy with at least one but typically less than three other family members. Interestingly, a large proportion of predicted redundant gene pairs were relatively old duplications (e.g., Ks > 1, suggesting that redundancy is stable over long evolutionary periods. Conclusions Machine learning predicts that most genes will have a functionally redundant paralog but will exhibit redundancy with relatively few genes within a family. The predictions and gene pair attributes for Arabidopsis provide a new resource for research in genetics and genome evolution. These techniques can now be applied to other organisms.

  13. How redundant are redundant color adjectives? An efficiency-based analysis of color overspecification

    Directory of Open Access Journals (Sweden)

    Paula eRubio-Fernández

    2016-02-01

    Full Text Available Color adjectives tend to be used redundantly in referential communication. I propose that redundant color adjectives are often intended to exploit a color contrast in the visual context and hence facilitate object identification, despite not being necessary to establish unique reference. Two language-production experiments investigated two types of factors that may affect the use of redundant color adjectives: factors related to the efficiency of color in the visual context and factors related to the semantic category of the noun. The results of Experiment 1 confirmed that people produce redundant color adjectives when color may facilitate object recognition; e.g., they do so more often in polychrome displays than in monochrome displays, and more often in English (pre-nominal position than in Spanish (post-nominal position. Redundant color adjectives are also used when color is a central property of the object category; e.g., people referred to the color of clothes more often than to the color of geometrical figures (Experiment 1, and they overspecified atypical colors more often than variable and stereotypical colors (Experiment 2. These results are relevant for pragmatic models of referential communication based on Gricean pragmatics and informativeness. An alternative analysis is proposed, which focuses on the efficiency and pertinence of color in a given referential situation.

  14. Language as an information system: redundancy and optimization

    Directory of Open Access Journals (Sweden)

    Irina Mikhaylovna Nekipelova

    2015-11-01

    Full Text Available The paper is devoted to research of the language system as an information system. The distinguishing feature of any natural living language system is redundant of elements of its structure. Redundancy, broken terms of universality peculiar to artificial information systems, makes language mobile in time and in space. It should be marked out informational redundancy of two types: language redundancy, when information overlay of language units within the system occurs and speech redundancy when condense of information into syntagmatic level occurs. Language redundancy is potential and speech redundancy is actual. In general, it should be noted that the language redundancy is necessary for language: complicating the relationships between language units, language redundancy creates in language situation of choice, leading to a disorder of language system, increasing of entropy and, as a result, the appearing of the information that can be accepted or cannot be by language system. Language redundancy is one of the reasons for growth of information in language. In addition, the information redundancy in language is one of the factors of language system development.

  15. The Effects of Race Conditions When Implementing Single-Source Redundant Clock Trees in Triple Modular Redundant Synchronous Architectures

    Science.gov (United States)

    Berg, Melanie D.; Kim, Hak S.; Phan, Anthony M.; Seidleck, Christina M.; Label, Kenneth A.; Pellish, Jonathan A.; Campola, Michael J.

    2016-01-01

    We present the challenges that arise when using redundant clock domains due to their time-skew. Radiation data show that a singular clock domain provides an improved triple modular redundant (TMR) scheme over redundant clocks.

  16. Method and apparatus for in-system redundant array repair on integrated circuits

    Science.gov (United States)

    Bright, Arthur A.; Crumley, Paul G.; Dombrowa, Marc B.; Douskey, Steven M.; Haring, Rudolf A.; Oakland, Steven F.; Ouellette, Michael R.; Strissel, Scott A.

    2007-12-18

    Disclosed is a method of repairing an integrated circuit of the type comprising of a multitude of memory arrays and a fuse box holding control data for controlling redundancy logic of the arrays. The method comprises the steps of providing the integrated circuit with a control data selector for passing the control data from the fuse box to the memory arrays; providing a source of alternate control data, external of the integrated circuit; and connecting the source of alternate control data to the control data selector. The method comprises the further step of, at a given time, passing the alternate control data from the source thereof, through the control data selector and to the memory arrays to control the redundancy logic of the memory arrays.

  17. Method and apparatus for in-system redundant array repair on integrated circuits

    Science.gov (United States)

    Bright, Arthur A [Croton-on-Hudson, NY; Crumley, Paul G [Yorktown Heights, NY; Dombrowa, Marc B [Bronx, NY; Douskey, Steven M [Rochester, MN; Haring, Rudolf A [Cortlandt Manor, NY; Oakland, Steven F [Colchester, VT; Ouellette, Michael R [Westford, VT; Strissel, Scott A [Byron, MN

    2008-07-29

    Disclosed is a method of repairing an integrated circuit of the type comprising of a multitude of memory arrays and a fuse box holding control data for controlling redundancy logic of the arrays. The method comprises the steps of providing the integrated circuit with a control data selector for passing the control data from the fuse box to the memory arrays; providing a source of alternate control data, external of the integrated circuit; and connecting the source of alternate control data to the control data selector. The method comprises the further step of, at a given time, passing the alternate control data from the source thereof, through the control data selector and to the memory arrays to control the redundancy logic of the memory arrays.

  18. Sibling rivalry: related bacterial small RNAs and their redundant and non-redundant roles.

    Science.gov (United States)

    Caswell, Clayton C; Oglesby-Sherrouse, Amanda G; Murphy, Erin R

    2014-01-01

    Small RNA molecules (sRNAs) are now recognized as key regulators controlling bacterial gene expression, as sRNAs provide a quick and efficient means of positively or negatively altering the expression of specific genes. To date, numerous sRNAs have been identified and characterized in a myriad of bacterial species, but more recently, a theme in bacterial sRNAs has emerged: the presence of more than one highly related sRNAs produced by a given bacterium, here termed sibling sRNAs. Sibling sRNAs are those that are highly similar at the nucleotide level, and while it might be expected that sibling sRNAs exert identical regulatory functions on the expression of target genes based on their high degree of relatedness, emerging evidence is demonstrating that this is not always the case. Indeed, there are several examples of bacterial sibling sRNAs with non-redundant regulatory functions, but there are also instances of apparent regulatory redundancy between sibling sRNAs. This review provides a comprehensive overview of the current knowledge of bacterial sibling sRNAs, and also discusses important questions about the significance and evolutionary implications of this emerging class of regulators.

  19. Sibling rivalry: Related bacterial small RNAs and their redundant and non-redundant roles

    Directory of Open Access Journals (Sweden)

    Clayton eCaswell

    2014-10-01

    Full Text Available Small RNA molecules (sRNAs are now recognized as key regulators controlling bacterial gene expression, as sRNAs provide a quick and efficient means of positively or negatively altering the expression of specific genes. To date, numerous sRNAs have been identified and characterized in a myriad of bacterial species, but more recently, a theme in bacterial sRNAs has emerged: the presence of more than one highly related sRNAs produced by a given bacterium, here termed sibling sRNAs. Sibling sRNAs are those that are highly similar at the nucleotide level, and while it might be expected that sibling sRNAs exert identical regulatory functions on the expression of target genes based on their high degree of relatedness, emerging evidence is demonstrating that this is not always the case. Indeed, there are several examples of bacterial sibling sRNAs with non-redundant regulatory functions, but there are also instances of apparent regulatory redundancy between sibling sRNAs. This review provides a comprehensive overview of the current knowledge of bacterial sibling sRNAs, and also discusses important questions about the significance and evolutionary implications of this emerging class of regulators.

  20. Global Energy-Optimal Redundancy Resolution of Hydraulic Manipulators: Experimental Results for a Forestry Manipulator

    Directory of Open Access Journals (Sweden)

    Jarmo Nurmi

    2017-05-01

    Full Text Available This paper addresses the energy-inefficiency problem of four-degrees-of-freedom (4-DOF hydraulic manipulators through redundancy resolution in robotic closed-loop controlled applications. Because conventional methods typically are local and have poor performance for resolving redundancy with respect to minimum hydraulic energy consumption, global energy-optimal redundancy resolution is proposed at the valve-controlled actuator and hydraulic power system interaction level. The energy consumption of the widely popular valve-controlled load-sensing (LS and constant-pressure (CP systems is effectively minimised through cost functions formulated in a discrete-time dynamic programming (DP approach with minimum state representation. A prescribed end-effector path and important actuator constraints at the position, velocity and acceleration levels are also satisfied in the solution. Extensive field experiments performed on a forestry hydraulic manipulator demonstrate the performance of the proposed solution. Approximately 15–30% greater hydraulic energy consumption was observed with the conventional methods in the LS and CP systems. These results encourage energy-optimal redundancy resolution in future robotic applications of hydraulic manipulators.

  1. High precision redundant robotic manipulator

    International Nuclear Information System (INIS)

    Young, K.K.D.

    1998-01-01

    A high precision redundant robotic manipulator for overcoming contents imposed by obstacles or imposed by a highly congested work space is disclosed. One embodiment of the manipulator has four degrees of freedom and another embodiment has seven degrees of freedom. Each of the embodiments utilize a first selective compliant assembly robot arm (SCARA) configuration to provide high stiffness in the vertical plane, a second SCARA configuration to provide high stiffness in the horizontal plane. The seven degree of freedom embodiment also utilizes kinematic redundancy to provide the capability of avoiding obstacles that lie between the base of the manipulator and the end effector or link of the manipulator. These additional three degrees of freedom are added at the wrist link of the manipulator to provide pitch, yaw and roll. The seven degrees of freedom embodiment uses one revolute point per degree of freedom. For each of the revolute joints, a harmonic gear coupled to an electric motor is introduced, and together with properly designed based servo controllers provide an end point repeatability of less than 10 microns. 3 figs

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

    CERN Document Server

    Bauer, Eric; Eustace, Dan

    2012-01-01

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

  3. Hybrid task priority-based motion control of a redundant free-floating space robot

    Directory of Open Access Journals (Sweden)

    Cheng ZHOU

    2017-12-01

    Full Text Available This paper presents a novel hybrid task priority-based motion planning algorithm of a space robot. The satellite attitude control task is defined as the primary task, while the least-squares-based non-strict task priority solution of the end-effector plus the multi-constraint task is viewed as the secondary task. Furthermore, a null-space task compensation strategy in the joint space is proposed to derive the combination of non-strict and strict task-priority motion planning, and this novel combination is termed hybrid task priority control. Thus, the secondary task is implemented in the primary task’s null-space. Besides, the transition of the state of multiple constraints between activeness and inactiveness will only influence the end-effector task without any effect on the primary task. A set of numerical experiments made in a real-time simulation system under Linux/RTAI shows the validity and feasibility of the proposed methodology. Keywords: Base attitude control, Hybrid task-priority, Motion planning, Multiple constraints, Redundant space robot

  4. Software engineering : redundancy is key

    NARCIS (Netherlands)

    Brand, van den M.G.J.; Groote, J.F.

    2015-01-01

    Software engineers are humans and so they make lots of mistakes. Typically 1 out of 10 to 100 tasks go wrong. The only way to avoid these mistakes is to introduce redundancy in the software engineering process. This article is a plea to consciously introduce several levels of redundancy for each

  5. Nonlinear Redundancy Analysis. Research Report 88-1.

    Science.gov (United States)

    van der Burg, Eeke; de Leeuw, Jan

    A non-linear version of redundancy analysis is introduced. The technique is called REDUNDALS. It is implemented within the computer program for canonical correlation analysis called CANALS. The REDUNDALS algorithm is of an alternating least square (ALS) type. The technique is defined as minimization of a squared distance between criterion…

  6. A new model for the redundancy allocation problem with component mixing and mixed redundancy strategy

    International Nuclear Information System (INIS)

    Gholinezhad, Hadi; Zeinal Hamadani, Ali

    2017-01-01

    This paper develops a new model for redundancy allocation problem. In this paper, like many recent papers, the choice of the redundancy strategy is considered as a decision variable. But, in our model each subsystem can exploit both active and cold-standby strategies simultaneously. Moreover, the model allows for component mixing such that components of different types may be used in each subsystem. The problem, therefore, boils down to determining the types of components, redundancy levels, and number of active and cold-standby units of each type for each subsystem to maximize system reliability by considering such constraints as available budget, weight, and space. Since RAP belongs to the NP-hard class of optimization problems, a genetic algorithm (GA) is developed for solving the problem. Finally, the performance of the proposed algorithm is evaluated by applying it to a well-known test problem from the literature with relatively satisfactory results. - Highlights: • A new model for the redundancy allocation problem in series–parallel systems is proposed. • The redundancy strategy of each subsystem is considered as a decision variable and can be active, cold-standby or mixed. • Component mixing is allowed, in other words components of any subsystem can be non-identical. • A genetic algorithm is developed for solving the problem. • Computational experiments demonstrate that the new model leads to interesting results.

  7. Redundancy in Nigerian Business Organizations: Alternatives ...

    African Journals Online (AJOL)

    This theoretical discourse examined the incidence of work redundancy in Nigerian organizations as to offer alternative options. Certainly, some redundancy exercises may be necessary for the survival of the organizations but certain variables may influence employees' reactions to the exercises and thus influence the ...

  8. Learners misperceive the benefits of redundant text in multimedia learning.

    Science.gov (United States)

    Fenesi, Barbara; Kim, Joseph A

    2014-01-01

    Research on metacognition has consistently demonstrated that learners fail to endorse instructional designs that produce benefits to memory, and often prefer designs that actually impair comprehension. Unlike previous studies in which learners were only exposed to a single multimedia design, the current study used a within-subjects approach to examine whether exposure to both redundant text and non-redundant text multimedia presentations improved learners' metacognitive judgments about presentation styles that promote better understanding. A redundant text multimedia presentation containing narration paired with verbatim on-screen text (Redundant) was contrasted with two non-redundant text multimedia presentations: (1) narration paired with images and minimal text (Complementary) or (2) narration paired with minimal text (Sparse). Learners watched presentation pairs of either Redundant + Complementary, or Redundant + Sparse. Results demonstrate that Complementary and Sparse presentations produced highest overall performance on the final comprehension assessment, but the Redundant presentation produced highest perceived understanding and engagement ratings. These findings suggest that learners misperceive the benefits of redundant text, even after direct exposure to a non-redundant, effective presentation.

  9. Quantum redundancies and local realism

    International Nuclear Information System (INIS)

    Horodecki, R.; Horodecki, P.

    1994-01-01

    The basic properties of quantum redundancies are presented. The previous definitions of the informationally coherent quantum (ICQ) system are generalized in terms of the redundancies. The ICQ systems are also considered in the context of local realism in terms of the information integrity factor η. The classical region η≤qslant[1]/[2] for the two classes of mixed, nonfactorizable states admitting the local hidden variable model is found. ((orig.))

  10. Redundancy in Nigerian Business Organizations: Alternatives (Pp ...

    African Journals Online (AJOL)

    FIRST LADY

    Redundancy in Nigerian Business Organizations: Alternatives (Pp. ... When business downturns ... The galloping pace of information technologies is a harbinger of profound ... Redundant staff in public departments can also be retained as.

  11. Redundant correlation effect on personalized recommendation

    Science.gov (United States)

    Qiu, Tian; Han, Teng-Yue; Zhong, Li-Xin; Zhang, Zi-Ke; Chen, Guang

    2014-02-01

    The high-order redundant correlation effect is investigated for a hybrid algorithm of heat conduction and mass diffusion (HHM), through both heat conduction biased (HCB) and mass diffusion biased (MDB) correlation redundancy elimination processes. The HCB and MDB algorithms do not introduce any additional tunable parameters, but keep the simple character of the original HHM. Based on two empirical datasets, the Netflix and MovieLens, the HCB and MDB are found to show better recommendation accuracy for both the overall objects and the cold objects than the HHM algorithm. Our work suggests that properly eliminating the high-order redundant correlations can provide a simple and effective approach to accurate recommendation.

  12. Redundancy in electronic health record corpora: analysis, impact on text mining performance and mitigation strategies.

    Science.gov (United States)

    Cohen, Raphael; Elhadad, Michael; Elhadad, Noémie

    2013-01-16

    The increasing availability of Electronic Health Record (EHR) data and specifically free-text patient notes presents opportunities for phenotype extraction. Text-mining methods in particular can help disease modeling by mapping named-entities mentions to terminologies and clustering semantically related terms. EHR corpora, however, exhibit specific statistical and linguistic characteristics when compared with corpora in the biomedical literature domain. We focus on copy-and-paste redundancy: clinicians typically copy and paste information from previous notes when documenting a current patient encounter. Thus, within a longitudinal patient record, one expects to observe heavy redundancy. In this paper, we ask three research questions: (i) How can redundancy be quantified in large-scale text corpora? (ii) Conventional wisdom is that larger corpora yield better results in text mining. But how does the observed EHR redundancy affect text mining? Does such redundancy introduce a bias that distorts learned models? Or does the redundancy introduce benefits by highlighting stable and important subsets of the corpus? (iii) How can one mitigate the impact of redundancy on text mining? We analyze a large-scale EHR corpus and quantify redundancy both in terms of word and semantic concept repetition. We observe redundancy levels of about 30% and non-standard distribution of both words and concepts. We measure the impact of redundancy on two standard text-mining applications: collocation identification and topic modeling. We compare the results of these methods on synthetic data with controlled levels of redundancy and observe significant performance variation. Finally, we compare two mitigation strategies to avoid redundancy-induced bias: (i) a baseline strategy, keeping only the last note for each patient in the corpus; (ii) removing redundant notes with an efficient fingerprinting-based algorithm. (a)For text mining, preprocessing the EHR corpus with fingerprinting yields

  13. Redundant interferometric calibration as a complex optimization problem

    Science.gov (United States)

    Grobler, T. L.; Bernardi, G.; Kenyon, J. S.; Parsons, A. R.; Smirnov, O. M.

    2018-05-01

    Observations of the redshifted 21 cm line from the epoch of reionization have recently motivated the construction of low-frequency radio arrays with highly redundant configurations. These configurations provide an alternative calibration strategy - `redundant calibration' - and boost sensitivity on specific spatial scales. In this paper, we formulate calibration of redundant interferometric arrays as a complex optimization problem. We solve this optimization problem via the Levenberg-Marquardt algorithm. This calibration approach is more robust to initial conditions than current algorithms and, by leveraging an approximate matrix inversion, allows for further optimization and an efficient implementation (`redundant STEFCAL'). We also investigated using the preconditioned conjugate gradient method as an alternative to the approximate matrix inverse, but found that its computational performance is not competitive with respect to `redundant STEFCAL'. The efficient implementation of this new algorithm is made publicly available.

  14. On Redundancy in Describing Linguistic Systems

    Directory of Open Access Journals (Sweden)

    Vladimir Borissov Pericliev

    2015-12-01

    Full Text Available On Redundancy in Describing Linguistic Systems The notion of system of linguistic elements figures prominently in most post-Saussurian linguistics up to the present. A “system” is the network of the contrastive (or, distinctive features each element in the system bears to the remaining elements. The meaning (valeur of each element in the system is the set of features that are necessary and jointly sufficient to distinguish this element from all others. The paper addresses the problems of “redundancy”, i.e. the occurrence of features that are not strictly necessary in describing an element in a system. Redundancy is shown to smuggle into the description of linguistic systems, this infelicitous practice illustrated with some examples from the literature (e.g. the classical phonemic analysis of Russian by Cherry, Halle, and Jakobson, 1953. The logic and psychology of the occurrence of redundancy are briefly sketched and it is shown that, in addition to some other problems, redundancy leads to a huge and unresolvable ambiguity of descriptions of linguistic systems (the Buridan’s ass problem.

  15. Optimal redundant systems for works with random processing time

    International Nuclear Information System (INIS)

    Chen, M.; Nakagawa, T.

    2013-01-01

    This paper studies the optimal redundant policies for a manufacturing system processing jobs with random working times. The redundant units of the parallel systems and standby systems are subject to stochastic failures during the continuous production process. First, a job consisting of only one work is considered for both redundant systems and the expected cost functions are obtained. Next, each redundant system with a random number of units is assumed for a single work. The expected cost functions and the optimal expected numbers of units are derived for redundant systems. Subsequently, the production processes of N tandem works are introduced for parallel and standby systems, and the expected cost functions are also summarized. Finally, the number of works is estimated by a Poisson distribution for the parallel and standby systems. Numerical examples are given to demonstrate the optimization problems of redundant systems

  16. The Application of S7-400H redundant PLC in I and C system for waterworks in nuclear power plant

    International Nuclear Information System (INIS)

    Pang Yuxiang

    2013-01-01

    This paper introduces Siemens S7-400H redundant PLC which is employed to implement monitor and control systems for waterworks in nuclear power plant. It focuses on the configuration and realization of the redundant system. The safety and reliability of the system is improved by using redundant CPU, network and server. (authors)

  17. Radiation-Tolerance Assessment of a Redundant Wireless Device

    Science.gov (United States)

    Huang, Q.; Jiang, J.

    2018-01-01

    This paper presents a method to evaluate radiation-tolerance without physical tests for a commercial off-the-shelf (COTS)-based monitoring device for high level radiation fields, such as those found in post-accident conditions in a nuclear power plant (NPP). This paper specifically describes the analysis of radiation environment in a severe accident, radiation damages in electronics, and the redundant solution used to prolong the life of the system, as well as the evaluation method for radiation protection and the analysis method of system reliability. As a case study, a wireless monitoring device with redundant and diversified channels is evaluated by using the developed method. The study results and system assessment data show that, under the given radiation condition, performance of the redundant device is more reliable and more robust than those non-redundant devices. The developed redundant wireless monitoring device is therefore able to apply in those conditions (up to 10 M Rad (Si)) during a severe accident in a NPP.

  18. Task-space separation principle: a force-field approach to motion planning for redundant manipulators.

    Science.gov (United States)

    Tommasino, Paolo; Campolo, Domenico

    2017-02-03

    In this work, we address human-like motor planning in redundant manipulators. Specifically, we want to capture postural synergies such as Donders' law, experimentally observed in humans during kinematically redundant tasks, and infer a minimal set of parameters to implement similar postural synergies in a kinematic model. For the model itself, although the focus of this paper is to solve redundancy by implementing postural strategies derived from experimental data, we also want to ensure that such postural control strategies do not interfere with other possible forms of motion control (in the task-space), i.e. solving the posture/movement problem. The redundancy problem is framed as a constrained optimization problem, traditionally solved via the method of Lagrange multipliers. The posture/movement problem can be tackled via the separation principle which, derived from experimental evidence, posits that the brain processes static torques (i.e. posture-dependent, such as gravitational torques) separately from dynamic torques (i.e. velocity-dependent). The separation principle has traditionally been applied at a joint torque level. Our main contribution is to apply the separation principle to Lagrange multipliers, which act as task-space force fields, leading to a task-space separation principle. In this way, we can separate postural control (implementing Donders' law) from various types of tasks-space movement planners. As an example, the proposed framework is applied to the (redundant) task of pointing with the human wrist. Nonlinear inverse optimization (NIO) is used to fit the model parameters and to capture motor strategies displayed by six human subjects during pointing tasks. The novelty of our NIO approach is that (i) the fitted motor strategy, rather than raw data, is used to filter and down-sample human behaviours; (ii) our framework is used to efficiently simulate model behaviour iteratively, until it converges towards the experimental human strategies.

  19. The Birth and Death of Redundancy in Decoherence and Quantum Darwinism

    Science.gov (United States)

    Riedel, Charles; Zurek, Wojciech; Zwolak, Michael

    2012-02-01

    Understanding the quantum-classical transition and the identification of a preferred classical domain through quantum Darwinism is based on recognizing high-redundancy states as both ubiquitous and exceptional. They are produced ubiquitously during decoherence, as has been demonstrated by the recent identification of very general conditions under which high-redundancy states develop. They are exceptional in that high-redundancy states occupy a very narrow corner of the global Hilbert space; states selected at random are overwelming likely to exhibit zero redundancy. In this letter, we examine the conditions and time scales for the transition from high-redundancy states to zero-redundancy states in many-body dynamics. We identify sufficient condition for the development of redundancy from product states and show that the destruction of redundancy can be accomplished even with highly constrained interactions.

  20. Selective Redundancy Removal: A Framework for Data Hiding

    Directory of Open Access Journals (Sweden)

    Ugo Fiore

    2010-02-01

    Full Text Available Data hiding techniques have so far concentrated on adding or modifying irrelevant information in order to hide a message. However, files in widespread use, such as HTML documents, usually exhibit high redundancy levels, caused by code-generation programs. Such redundancy may be removed by means of optimization software. Redundancy removal, if applied selectively, enables information hiding. This work introduces Selective Redundancy Removal (SRR as a framework for hiding data. An example application of the framework is given in terms of hiding information in HTML documents. Non-uniformity across documents may raise alarms. Nevertheless, selective application of optimization techniques might be due to the legitimate use of optimization software not supporting all the optimization methods, or configured to not use all of them.

  1. Prioritising Redundant Network Component for HOWBAN Survivability Using FMEA

    Directory of Open Access Journals (Sweden)

    Cheong Loong Chan

    2017-01-01

    Full Text Available Deploying redundant component is the ubiquitous approach to improve the reliability and survivability of a hybrid optical wireless broadband access network (HOWBAN. Much work has been done to study the cost and impact of deploying redundant component in the network but no formal tools have been used to enable the evaluation and decision to prioritise the deployment of redundant facilities in the network. In this paper we show how FMEA (Failure Mode Effect and Analysis technique can be adapted to identify the critical segment in the network and prioritise the redundant component to be deployed to ensure network survivability. Our result showed that priority must be given to redundancy to mitigate grid power outage particularly in less developed countries which is poised for rapid expansion in broadband services.

  2. Reliability optimization of a redundant system with failure dependencies

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-12-15

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

  3. Reliability optimization of a redundant system with failure dependencies

    International Nuclear Information System (INIS)

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

    2007-01-01

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

  4. Exploiting Redundancy in an OFDM SDR Receiver

    Directory of Open Access Journals (Sweden)

    Tomas Palenik

    2009-01-01

    Full Text Available Common OFDM system contains redundancy necessary to mitigate interblock interference and allows computationally effective single-tap frequency domain equalization in receiver. Assuming the system implements an outer error correcting code and channel state information is available in the receiver, we show that it is possible to understand the cyclic prefix insertion as a weak inner ECC encoding and exploit the introduced redundancy to slightly improve error performance of such a system. In this paper, an easy way to implement modification to an existing SDR OFDM receiver is presented. This modification enables the utilization of prefix redundancy, while preserving full compatibility with existing OFDM-based communication standards.

  5. The heuristic value of redundancy models of aging.

    Science.gov (United States)

    Boonekamp, Jelle J; Briga, Michael; Verhulst, Simon

    2015-11-01

    Molecular studies of aging aim to unravel the cause(s) of aging bottom-up, but linking these mechanisms to organismal level processes remains a challenge. We propose that complementary top-down data-directed modelling of organismal level empirical findings may contribute to developing these links. To this end, we explore the heuristic value of redundancy models of aging to develop a deeper insight into the mechanisms causing variation in senescence and lifespan. We start by showing (i) how different redundancy model parameters affect projected aging and mortality, and (ii) how variation in redundancy model parameters relates to variation in parameters of the Gompertz equation. Lifestyle changes or medical interventions during life can modify mortality rate, and we investigate (iii) how interventions that change specific redundancy parameters within the model affect subsequent mortality and actuarial senescence. Lastly, as an example of data-directed modelling and the insights that can be gained from this, (iv) we fit a redundancy model to mortality patterns observed by Mair et al. (2003; Science 301: 1731-1733) in Drosophila that were subjected to dietary restriction and temperature manipulations. Mair et al. found that dietary restriction instantaneously reduced mortality rate without affecting aging, while temperature manipulations had more transient effects on mortality rate and did affect aging. We show that after adjusting model parameters the redundancy model describes both effects well, and a comparison of the parameter values yields a deeper insight in the mechanisms causing these contrasting effects. We see replacement of the redundancy model parameters by more detailed sub-models of these parameters as a next step in linking demographic patterns to underlying molecular mechanisms. Copyright © 2015 Elsevier Inc. All rights reserved.

  6. Redundancy and Reliability for an HPC Data Centre

    OpenAIRE

    Erhan Yılmaz

    2012-01-01

    Defining a level of redundancy is a strategic question when planning a new data centre, as it will directly impact the entire design of the building as well as the construction and operational costs. It will also affect how to integrate future extension plans into the design. Redundancy is also a key strategic issue when upgrading or retrofitting an existing facility. Redundancy is a central strategic question to any business that relies on data centres for its operation. In th...

  7. Redundant manipulator techniques for partially decentralized path planning and control of a platoon of autonomous vehicles.

    Science.gov (United States)

    Stilwell, Daniel J; Bishop, Bradley E; Sylvester, Caleb A

    2005-08-01

    An approach to real-time trajectory generation for platoons of autonomous vehicles is developed from well-known control techniques for redundant robotic manipulators. The partially decentralized structure of this approach permits each vehicle to independently compute its trajectory in real-time using only locally generated information and low-bandwidth feedback generated by a system exogenous to the platoon. Our work is motivated by applications for which communications bandwidth is severely limited, such for platoons of autonomous underwater vehicles. The communication requirements for our trajectory generation approach are independent of the number of vehicles in the platoon, enabling platoons composed of a large number of vehicles to be coordinated despite limited communication bandwidth.

  8. Self-Healing Networks: Redundancy and Structure

    Science.gov (United States)

    Quattrociocchi, Walter; Caldarelli, Guido; Scala, Antonio

    2014-01-01

    We introduce the concept of self-healing in the field of complex networks modelling; in particular, self-healing capabilities are implemented through distributed communication protocols that exploit redundant links to recover the connectivity of the system. We then analyze the effect of the level of redundancy on the resilience to multiple failures; in particular, we measure the fraction of nodes still served for increasing levels of network damages. Finally, we study the effects of redundancy under different connectivity patterns—from planar grids, to small-world, up to scale-free networks—on healing performances. Small-world topologies show that introducing some long-range connections in planar grids greatly enhances the resilience to multiple failures with performances comparable to the case of the most resilient (and least realistic) scale-free structures. Obvious applications of self-healing are in the important field of infrastructural networks like gas, power, water, oil distribution systems. PMID:24533065

  9. Motion compensation via redundant-wavelet multihypothesis.

    Science.gov (United States)

    Fowler, James E; Cui, Suxia; Wang, Yonghui

    2006-10-01

    Multihypothesis motion compensation has been widely used in video coding with previous attention focused on techniques employing predictions that are diverse spatially or temporally. In this paper, the multihypothesis concept is extended into the transform domain by using a redundant wavelet transform to produce multiple predictions that are diverse in transform phase. The corresponding multiple-phase inverse transform implicitly combines the phase-diverse predictions into a single spatial-domain prediction for motion compensation. The performance advantage of this redundant-wavelet-multihypothesis approach is investigated analytically, invoking the fact that the multiple-phase inverse involves a projection that significantly reduces the power of a dense-motion residual modeled as additive noise. The analysis shows that redundant-wavelet multihypothesis is capable of up to a 7-dB reduction in prediction-residual variance over an equivalent single-phase, single-hypothesis approach. Experimental results substantiate the performance advantage for a block-based implementation.

  10. Finite-Horizon $H_\\infty $ Consensus for Multiagent Systems With Redundant Channels via An Observer-Type Event-Triggered Scheme.

    Science.gov (United States)

    Xu, Wenying; Wang, Zidong; Ho, Daniel W C

    2018-05-01

    This paper is concerned with the finite-horizon consensus problem for a class of discrete time-varying multiagent systems with external disturbances and missing measurements. To improve the communication reliability, redundant channels are introduced and the corresponding protocol is constructed for the information transmission over redundant channels. An event-triggered scheme is adopted to determine whether the information of agents should be transmitted to their neighbors. Subsequently, an observer-type event-triggered control protocol is proposed based on the latest received neighbors' information. The purpose of the addressed problem is to design a time-varying controller based on the observed information to achieve the consensus performance in a finite horizon. By utilizing a constrained recursive Riccati difference equation approach, some sufficient conditions are obtained to guarantee the consensus performance, and the controller parameters are also designed. Finally, a numerical example is provided to demonstrate the desired reliability of redundant channels and the effectiveness of the event-triggered control protocol.

  11. Detection of sensor failures in nuclear plants using analytic redundancy

    International Nuclear Information System (INIS)

    Kitamura, M.

    1980-01-01

    A method for on-line, nonperturbative detection and identification of sensor failures in nuclear power plants was studied to determine its feasibility. This method is called analytic redundancy, or functional redundancy. Sensor failure has traditionally been detected by comparing multiple signals from redundant sensors, such as in two-out-of-three logic. In analytic redundancy, with the help of an assumed model of the physical system, the signals from a set of sensors are processed to reproduce the signals from all system sensors

  12. Reliability of redundant structures of nuclear reactor protection systems

    International Nuclear Information System (INIS)

    Vojnovic, B.

    1983-01-01

    In this paper, reliability of various redundant structures of PWR protection systems has been analysed. Structures of reactor tip systems as well as the systems for activation of safety devices have been presented. In all those systems redundancy is achieved by means of so called majority voting logic ('r out of n' structures). Different redundant devices have been compared, concerning probability of occurrence of safe as well as unsafe failures. (author)

  13. Signal validation in nuclear power plants using redundant measurements

    International Nuclear Information System (INIS)

    Glockler, O.; Upadhyaya, B.R.; Morgenstern, V.M.

    1989-01-01

    This paper discusses the basic principles of a multivariable signal validation software system utilizing redundant sensor readings of process variables in nuclear power plants (NPPs). The technique has been tested in numerical experiments, and was applied to actual data from a pressurized water reactor (PWR). The simultaneous checking within one redundant measurement set, and the cross-checking among redundant measurement sets of dissimilar process variables, results in an algorithm capable of detecting and isolating bias-type errors. A case in point occurs when a majority of the direct redundant measurements of more than one process variable has failed simultaneously by a common-mode or correlated failures can be detected by the developed approach. 5 refs

  14. Optimally efficient swimming in hyper-redundant mechanisms: control, design, and energy recovery

    International Nuclear Information System (INIS)

    Wiens, A J; Nahon, M

    2012-01-01

    Hyper-redundant mechanisms (HRMs), also known as snake-like robots, are highly adaptable during locomotion on land. Researchers are currently working to extend their capabilities to aquatic environments through biomimetic undulatory propulsion. In addition to increasing the versatility of the system, truly biomimetic swimming could also provide excellent locomotion efficiency. Unfortunately, the complexity of the system precludes the development of a functional solution to achieve this. To explore this problem, a rapid optimization process is used to generate efficient HRM swimming gaits. The low computational cost of the approach allows for multiple optimizations over a broad range of system conditions. By observing how these conditions affect optimal kinematics, a number of new insights are developed regarding undulatory swimming in robotic systems. Two key conditions are varied within the study, swimming speed and energy recovery. It is found that the swimmer mimics the speed control behaviour of natural fish and that energy recovery drastically increases the system's efficiency. Remarkably, this efficiency increase is accompanied by a distinct change in swimming kinematics. With energy recovery, the swimmer converges to a clearly anguilliform gait, without, it tends towards the carangiform mode. (paper)

  15. Design of SCADA water resource management control center by a bi-objective redundancy allocation problem and particle swarm optimization

    International Nuclear Information System (INIS)

    Dolatshahi-Zand, Ali; Khalili-Damghani, Kaveh

    2015-01-01

    SCADA is an essential system to control critical facilities in big cities. SCADA is utilized in several sectors such as water resource management, power plants, electricity distribution centers, traffic control centers, and gas deputy. The failure of SCADA results in crisis. Hence, the design of SCADA system in order to serve a high reliability considering limited budget and other constraints is essential. In this paper, a bi-objective redundancy allocation problem (RAP) is proposed to design Tehran's SCADA water resource management control center. Reliability maximization and cost minimization are concurrently considered. Since the proposed RAP is a non-linear multi-objective mathematical programming so the exact methods cannot efficiently handle it. A multi-objective particle swarm optimization (MOPSO) algorithm is designed to solve it. Several features such as dynamic parameter tuning, efficient constraint handling and Pareto gridding are inserted in proposed MOPSO. The results of proposed MOPSO are compared with an efficient ε-constraint method. Several non-dominated designs of SCADA system are generated using both methods. Comparison metrics based on accuracy and diversity of Pareto front are calculated for both methods. The proposed MOPSO algorithm reports better performance. Finally, in order to choose the practical design, the TOPSIS algorithm is used to prune the Pareto front. - Highlights: • Multi-objective redundancy allocation problem (MORAP) is proposed to design SCADA system. • Multi-objective particle swarm optimization (MOPSO) is proposed to solve MORAP. • Efficient epsilon-constraint method is adapted to solve MORAP. • Non-dominated solutions are generated on Pareto front of MORAP by both methods. • Several multi-objective metrics are calculated to compare the performance of methods

  16. WIND TUNNEL EVALUATION FOR CONTROL TRANSITION FROM ELEVATOR TO STABILATOR OF SMALL UAV

    Directory of Open Access Journals (Sweden)

    ZULHILMY SAHWEE

    2017-06-01

    Full Text Available Faulty control surface actuator in a small Unmanned Aerial Vehicles (sUAV could be overcome with a few techniques. Redundant actuators, analytical redundancy or combination of both are normally used as fault accommodation techniques. In this paper, the accommodation technique of faulty elevator actuator is presented. This technique uses a standby control surface as temporary control reallocation. Wind tunnel measurement facility is set up for the experimental validation and it is compared with FoilSim software. Flat plate airfoil which was used as horizontal stabilizer, is simulated using numerical model and it is validated using the wind tunnel test. Then, a flat airfoil is designed to be used as stabilator for the recovery of faulty elevator actuator. Results show the different deflection angle is needed when transferring from one control surface to another. From the analysis, the proposed method could be implemented without affecting the pitch stability during control surface transition. The alternate control surface accommodation technique proves to be promising for higher reliability sUAV in the case of a faulty on-board actuator.

  17. Trophic redundancy reduces vulnerability to extinction cascades.

    Science.gov (United States)

    Sanders, Dirk; Thébault, Elisa; Kehoe, Rachel; Frank van Veen, F J

    2018-03-06

    Current species extinction rates are at unprecedentedly high levels. While human activities can be the direct cause of some extinctions, it is becoming increasingly clear that species extinctions themselves can be the cause of further extinctions, since species affect each other through the network of ecological interactions among them. There is concern that the simplification of ecosystems, due to the loss of species and ecological interactions, increases their vulnerability to such secondary extinctions. It is predicted that more complex food webs will be less vulnerable to secondary extinctions due to greater trophic redundancy that can buffer against the effects of species loss. Here, we demonstrate in a field experiment with replicated plant-insect communities, that the probability of secondary extinctions is indeed smaller in food webs that include trophic redundancy. Harvesting one species of parasitoid wasp led to secondary extinctions of other, indirectly linked, species at the same trophic level. This effect was markedly stronger in simple communities than for the same species within a more complex food web. We show that this is due to functional redundancy in the more complex food webs and confirm this mechanism with a food web simulation model by highlighting the importance of the presence and strength of trophic links providing redundancy to those links that were lost. Our results demonstrate that biodiversity loss, leading to a reduction in redundant interactions, can increase the vulnerability of ecosystems to secondary extinctions, which, when they occur, can then lead to further simplification and run-away extinction cascades. Copyright © 2018 the Author(s). Published by PNAS.

  18. Mobility and Position Error Analysis of a Complex Planar Mechanism with Redundant Constraints

    Science.gov (United States)

    Sun, Qipeng; Li, Gangyan

    2018-03-01

    Nowadays mechanisms with redundant constraints have been created and attracted much attention for their merits. The mechanism of the redundant constraints in a mechanical system is analyzed in this paper. A analysis method of Planar Linkage with a repetitive structure is proposed to get the number and type of constraints. According to the difference of applications and constraint characteristics, the redundant constraints are divided into the theoretical planar redundant constraints and the space-planar redundant constraints. And the calculation formula for the number of redundant constraints and type of judging method are carried out. And a complex mechanism with redundant constraints is analyzed of the influence about redundant constraints on mechanical performance. With the combination of theoretical derivation and simulation research, a mechanism analysis method is put forward about the position error of complex mechanism with redundant constraints. It points out the direction on how to eliminate or reduce the influence of redundant constraints.

  19. Control of thumb force using surface functional electrical stimulation and muscle load sharing

    Science.gov (United States)

    2013-01-01

    Background Stroke survivors often have difficulties in manipulating objects with their affected hand. Thumb control plays an important role in object manipulation. Surface functional electrical stimulation (FES) can assist movement. We aim to control the 2D thumb force by predicting the sum of individual muscle forces, described by a sigmoidal muscle recruitment curve and a single force direction. Methods Five able bodied subjects and five stroke subjects were strapped in a custom built setup. The forces perpendicular to the thumb in response to FES applied to three thumb muscles were measured. We evaluated the feasibility of using recruitment curve based force vector maps in predicting output forces. In addition, we developed a closed loop force controller. Load sharing between the three muscles was used to solve the redundancy problem having three actuators to control forces in two dimensions. The thumb force was controlled towards target forces of 0.5 N and 1.0 N in multiple directions within the individual’s thumb work space. Hereby, the possibilities to use these force vector maps and the load sharing approach in feed forward and feedback force control were explored. Results The force vector prediction of the obtained model had small RMS errors with respect to the actual measured force vectors (0.22±0.17 N for the healthy subjects; 0.17±0.13 N for the stroke subjects). The stroke subjects showed a limited work range due to limited force production of the individual muscles. Performance of feed forward control without feedback, was better in healthy subjects than in stroke subjects. However, when feedback control was added performances were similar between the two groups. Feedback force control lead, especially for the stroke subjects, to a reduction in stationary errors, which improved performance. Conclusions Thumb muscle responses to FES can be described by a single force direction and a sigmoidal recruitment curve. Force in desired direction can be

  20. Joint optimization of redundancy level and spare part inventories

    International Nuclear Information System (INIS)

    Sleptchenko, Andrei; Heijden, Matthieu van der

    2016-01-01

    We consider a “k-out-of-N” system with different standby modes. Each of the N components consists of multiple part types. Upon failure, a component can be repaired within a certain time by switching the failed part by a spare, if available. We develop both an exact and a fast approximate analysis to compute the system availability. Next, we jointly optimize the component redundancy level with the inventories of the various spare parts. We find that our approximations are very accurate and suitable for large systems. We apply our model to a case study at a public organization in Qatar, and find that we can improve the availability-to-cost ratio by reducing the redundancy level and increasing the spare part inventories. In general, high redundancy levels appear to be useful only when components are relatively cheap and part replacement times are high. - Highlights: • We analyze a redundant system (k-out-of-N) with multiple parts and spares. • We jointly optimize the redundancy level and the spare part inventories. • We develop an exact method and an approximation to evaluate the system availability. • Adding spare parts and reducing the redundancy level cuts cost by 50% in a case study. • The availability is not very sensitive to the shape of the failure time distribution.

  1. Two-stage simplified swarm optimization for the redundancy allocation problem in a multi-state bridge system

    International Nuclear Information System (INIS)

    Lai, Chyh-Ming; Yeh, Wei-Chang

    2016-01-01

    The redundancy allocation problem involves configuring an optimal system structure with high reliability and low cost, either by alternating the elements with more reliable elements and/or by forming them redundantly. The multi-state bridge system is a special redundancy allocation problem and is commonly used in various engineering systems for load balancing and control. Traditional methods for redundancy allocation problem cannot solve multi-state bridge systems efficiently because it is impossible to transfer and reduce a multi-state bridge system to series and parallel combinations. Hence, a swarm-based approach called two-stage simplified swarm optimization is proposed in this work to effectively and efficiently solve the redundancy allocation problem in a multi-state bridge system. For validating the proposed method, two experiments are implemented. The computational results indicate the advantages of the proposed method in terms of solution quality and computational efficiency. - Highlights: • Propose two-stage SSO (SSO_T_S) to deal with RAP in multi-state bridge system. • Dynamic upper bound enhances the efficiency of searching near-optimal solution. • Vector-update stages reduces the problem dimensions. • Statistical results indicate SSO_T_S is robust both in solution quality and runtime.

  2. Resolving kinematic redundancy with constraints using the FSP (Full Space Parameterization) approach

    International Nuclear Information System (INIS)

    Pin, F.G.; Tulloch, F.A.

    1996-01-01

    A solution method is presented for the motion planning and control of kinematically redundant serial-link manipulators in the presence of motion constraints such as joint limits or obstacles. Given a trajectory for the end-effector, the approach utilizes the recently proposed Full Space Parameterization (FSP) method to generate a parameterized expression for the entire space of solutions of the unconstrained system. At each time step, a constrained optimization technique is then used to analytically find the specific joint motion solution that satisfies the desired task objective and all the constraints active during the time step. The method is applicable to systems operating in a priori known environments or in unknown environments with sensor-based obstacle detection. The derivation of the analytical solution is first presented for a general type of kinematic constraint and is then applied to the problem of motion planning for redundant manipulators with joint limits and obstacle avoidance. Sample results using planar and 3-D manipulators with various degrees of redundancy are presented to illustrate the efficiency and wide applicability of constrained motion planning using the FSP approach

  3. Working memory capacity and redundant information processing efficiency.

    Science.gov (United States)

    Endres, Michael J; Houpt, Joseph W; Donkin, Chris; Finn, Peter R

    2015-01-01

    Working memory capacity (WMC) is typically measured by the amount of task-relevant information an individual can keep in mind while resisting distraction or interference from task-irrelevant information. The current research investigated the extent to which differences in WMC were associated with performance on a novel redundant memory probes (RMP) task that systematically varied the amount of to-be-remembered (targets) and to-be-ignored (distractor) information. The RMP task was designed to both facilitate and inhibit working memory search processes, as evidenced by differences in accuracy, response time, and Linear Ballistic Accumulator (LBA) model estimates of information processing efficiency. Participants (N = 170) completed standard intelligence tests and dual-span WMC tasks, along with the RMP task. As expected, accuracy, response-time, and LBA model results indicated memory search and retrieval processes were facilitated under redundant-target conditions, but also inhibited under mixed target/distractor and redundant-distractor conditions. Repeated measures analyses also indicated that, while individuals classified as high (n = 85) and low (n = 85) WMC did not differ in the magnitude of redundancy effects, groups did differ in the efficiency of memory search and retrieval processes overall. Results suggest that redundant information reliably facilitates and inhibits the efficiency or speed of working memory search, and these effects are independent of more general limits and individual differences in the capacity or space of working memory.

  4. The development of robotic system for the nuclear power plants - A study on the manipulation of teleoperation system using redundant robot

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Chung Oh; Cho, Hyung Seok; Jang, Pyung Hoon; Park, Ki Chul; Hyun, Jang Hwan; Kim, Joo Gon; Park, Young Joon; Hwang, Woong Tae; Jeon, Yong Soo; Lee, Joo Yeon; Ahn, Kyung Mo [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)

    1996-07-01

    In this project the following 4 sub- projects have been studied for use in nuclear power plants. 1) Development of precision control method for the hydraulic and pneumatic actuators: The fuzzy gain tuner for the pneumatic servo position control system with the state feedback controller was designed= by using the professional knowledge. Through the experimental study, this control method was verified to obtain the optimal fain automatically. 2) Development of an universal master arm and force reflecting teleoperation system: An autonomous telerobot system with a vision based force reflection capability was developed. To effectly implement visual force feedback, 3 different control methods were also developed. 3) A study on the analysis and control of the redundant robot manipulator: An optimal joint-path of 8-DOF redundant KAEROT for the nozzle dam task was generated and its effectiveness and safety was verified by using graphic/animation tool. The proposed dynamic control algorithm for the redundant robot was applied to the experiment of planar 3- DOF redundant robot, showing good performance. 4) A study on the robot/user interface design: A set of final design and its console table was developed, which has metaphorical identity and user-friendly interface and a study mock-up was also developed to identify the possibility in a clear form. 33 refs., 3 tabs., 11 figs. (author)

  5. Analysis and Design of Offset QPSK Using Redundant Filter Banks

    International Nuclear Information System (INIS)

    Fernandez-Vazquez, Alfonso; Jovanovic-Dolecek, Gordana

    2013-01-01

    This paper considers the analysis and design of OQPSK digital modulation. We first establish the discrete time formulation, which allows us to find the equivalent redundant filter banks. It is well known that redundant filter banks are related with redundant transformation of the Frame theory. According to the Frame theory, the redundant transformations and corresponding representations are not unique. In this way, we show that the solution to the pulse shaping problem is not unique. Then we use this property to minimize the effect of the channel noise in the reconstructed symbol stream. We evaluate the performance of the digital communication using numerical examples.

  6. Redundancy for electric motors in spacecraft applications

    Science.gov (United States)

    Smith, Robert J.; Flew, Alastair R.

    1986-01-01

    The parts of electric motors which should be duplicated in order to provide maximum reliability in spacecraft application are identified. Various common types of redundancy are described. The advantages and disadvantages of each are noted. The principal types are illustrated by reference to specific examples. For each example, constructional details, basic performance data and failure modes are described, together with a discussion of the suitability of particular redundancy techniques to motor types.

  7. Study of redundant Models in reliability prediction of HXMT's HES

    International Nuclear Information System (INIS)

    Wang Jinming; Liu Congzhan; Zhang Zhi; Ji Jianfeng

    2010-01-01

    Two redundant equipment structures of HXMT's HES are proposed firstly, the block backup and dual system cold-redundancy. Then prediction of the reliability is made by using parts count method. Research of comparison and analysis is also performed on the two proposals. A conclusion is drawn that a higher reliability and longer service life could be offered by taking a redundant equipment structure of block backup. (authors)

  8. 3D seismic denoising based on a low-redundancy curvelet transform

    International Nuclear Information System (INIS)

    Cao, Jingjie; Zhao, Jingtao; Hu, Zhiying

    2015-01-01

    Contamination of seismic signal with noise is one of the main challenges during seismic data processing. Several methods exist for eliminating different types of noises, but optimal random noise attenuation remains difficult. Based on multi-scale, multi-directional locality of curvelet transform, the curvelet thresholding method is a relatively new method for random noise elimination. However, the high redundancy of a 3D curvelet transform makes its computational time and memory for massive data processing costly. To improve the efficiency of the curvelet thresholding denoising, a low-redundancy curvelet transform was introduced. The redundancy of the low-redundancy curvelet transform is approximately one-quarter of the original transform and the tightness of the original transform is also kept, thus the low-redundancy curvelet transform calls for less memory and computational resource compared with the original one. Numerical results on 3D synthetic and field data demonstrate that the low-redundancy curvelet denoising consumes one-quarter of the CPU time compared with the original curvelet transform using iterative thresholding denoising when comparable results are obtained. Thus, the low-redundancy curvelet transform is a good candidate for massive seismic denoising. (paper)

  9. Coherent network detection of gravitational waves: the redundancy veto

    International Nuclear Information System (INIS)

    Wen Linqing; Schutz, Bernard F

    2005-01-01

    A network of gravitational wave detectors is called redundant if, given the direction to a source, the strain induced by a gravitational wave in one or more of the detectors can be fully expressed in terms of the strain induced in others in the network. Because gravitational waves have only two polarizations, any network of three or more differently oriented interferometers with similar observing bands is redundant. The three-armed LISA space interferometer has three outputs that are redundant at low frequencies. The two aligned LIGO interferometers at Hanford WA are redundant, and the LIGO detector at Livingston LA is nearly redundant with either of the Hanford detectors. Redundant networks have a powerful veto against spurious noise, a linear combination of the detector outputs that contains no gravitational wave signal. For LISA, this 'null' output is known as the Sagnac mode, and its use in discriminating between detector noise and a cosmological gravitational wave background is well understood. But the usefulness of the null veto for ground-based detector networks has been ignored until now. We show that it should make it possible to discriminate in a model-independent way between real gravitational waves and accidentally coincident non-Gaussian noise 'events' in redundant networks of two or more broadband detectors. It has been shown that with three detectors, the null output can even be used to locate the direction to the source, and then two other linear combinations of detector outputs give the optimal 'coherent' reconstruction of the two polarization components of the signal. We discuss briefly the implementation of such a detection strategy in realistic networks, where signals are weak, detector calibration is a significant uncertainty, and the various detectors may have different (but overlapping) observing bands

  10. The cellular robustness by genetic redundancy in budding yeast.

    Directory of Open Access Journals (Sweden)

    Jingjing Li

    2010-11-01

    Full Text Available The frequent dispensability of duplicated genes in budding yeast is heralded as a hallmark of genetic robustness contributed by genetic redundancy. However, theoretical predictions suggest such backup by redundancy is evolutionarily unstable, and the extent of genetic robustness contributed from redundancy remains controversial. It is anticipated that, to achieve mutual buffering, the duplicated paralogs must at least share some functional overlap. However, counter-intuitively, several recent studies reported little functional redundancy between these buffering duplicates. The large yeast genetic interactions released recently allowed us to address these issues on a genome-wide scale. We herein characterized the synthetic genetic interactions for ∼500 pairs of yeast duplicated genes originated from either whole-genome duplication (WGD or small-scale duplication (SSD events. We established that functional redundancy between duplicates is a pre-requisite and thus is highly predictive of their backup capacity. This observation was particularly pronounced with the use of a newly introduced metric in scoring functional overlap between paralogs on the basis of gene ontology annotations. Even though mutual buffering was observed to be prevalent among duplicated genes, we showed that the observed backup capacity is largely an evolutionarily transient state. The loss of backup capacity generally follows a neutral mode, with the buffering strength decreasing in proportion to divergence time, and the vast majority of the paralogs have already lost their backup capacity. These observations validated previous theoretic predictions about instability of genetic redundancy. However, departing from the general neutral mode, intriguingly, our analysis revealed the presence of natural selection in stabilizing functional overlap between SSD pairs. These selected pairs, both WGD and SSD, tend to have decelerated functional evolution, have higher propensities of co

  11. Redundant nerve roots of the cauda equina : MR findings

    International Nuclear Information System (INIS)

    Oh, Kyu Hyen; Lee, Jung Man; Jung, Hak Young; Lee, Young Hwan; Sung, Nak Kwan; Chung, Duck Soo; Kim, Ok Dong; Lee, Sang Kwon; Suh, Kyung Jin

    1997-01-01

    To evaluate MR findings of redundant nerve roots (RNR) of the cauda equina. 17 patients with RNR were studied; eight were men and nine were women, and their ages ranged from 46 to 82 (mean 63) years. Diagroses were established on the basis of T2-weighted sagittal and coronal MRI, which showed a tortuous or coiled configuration of the nerve roots of the cauda equina. MR findings were reviewed for location, magnitude, and signal intensity of redundant nerve roots, and the relationship between magnitude of redundancy and severity of lumbar spinal canal stenosis (LSCS) was evaluated. In all 17 patients, MR showed moderate or severe LSCS caused by herniation or bulging of an intervertebral disc, osteophyte from the vertebral body or facet joint, thickening of the ligamentum flavum, degenerative spondylolisthesis, or a combination of these. T2-weighted sagittal and coronal MR images well clearly showed the location of RNR of the cauda equina;in 16 patients(94%), these were seen above the level of constriction of the spinal canal, and in one case, they were observed below the level of constriction. T2-weighted axial images showed the thecal sac filled with numerous nerve roots. The magnitude of RNR was mild in six cases (35%), moderate in five cases (30%), and severe in six cases (35%). Compared with normal nerve roots, the RNR signal on T2-weighted images was iso-intense. All patients with severe redundancy showed severe LSCS, but not all cases with severe LSCS showed severe redundancy. Redundant nerve roots of cauda equina were seen in relatively older patients with moderate or severe LSCS and T2-weighted MR images were accurate in identifying redundancy of nerve roots and evaluating their magnitude and location

  12. Capillary response to skeletal muscle contraction: evidence that redundancy between vasodilators is physiologically relevant during active hyperaemia.

    Science.gov (United States)

    Lamb, Iain R; Novielli, Nicole M; Murrant, Coral L

    2018-04-15

    The current theory behind matching blood flow to metabolic demand of skeletal muscle suggests redundant interactions between metabolic vasodilators. Capillaries play an important role in blood flow control given their ability to respond to muscle contraction by causing conducted vasodilatation in upstream arterioles that control their perfusion. We sought to determine whether redundancies occur between vasodilators at the level of the capillary by stimulating the capillaries with muscle contraction and vasodilators relevant to muscle contraction. We identified redundancies between potassium and both adenosine and nitric oxide, between nitric oxide and potassium, and between adenosine and both potassium and nitric oxide. During muscle contraction, we demonstrate redundancies between potassium and nitric oxide as well as between potassium and adenosine. Our data show that redundancy is physiologically relevant and involved in the coordination of the vasodilator response during muscle contraction at the level of the capillaries. We sought to determine if redundancy between vasodilators is physiologically relevant during active hyperaemia. As inhibitory interactions between vasodilators are indicative of redundancy, we tested whether vasodilators implicated in mediating active hyperaemia (potassium (K + ), adenosine (ADO) and nitric oxide (NO)) inhibit one another's vasodilatory effects through direct application of pharmacological agents and during muscle contraction. Using the hamster cremaster muscle and intravital microscopy, we locally stimulated capillaries with one vasodilator in the absence and the presence of a second vasodilator (10 -7 m S-nitroso-N-acetylpenicillamine (SNAP), 10 -7 m ADO, 10 mm KCl) applied sequentially and simultaneously, and observed the response in the associated upstream 4A arteriole controlling the perfusion of the stimulated capillary. We found that KCl significantly attenuated SNAP- and ADO-induced vasodilatations by ∼49.7% and

  13. Coordination of dual robot arms using kinematic redundancy

    Science.gov (United States)

    Suh, Il Hong; Shin, Kang G.

    1988-01-01

    A method is developed to coordinate the motion of dual robot arms carrying a solid object, where the first robot (leader) grasps one end of the object rigidly and the second robot (follower) is allowed to change its grasping position at the other end of the object along the object surface while supporting the object. It is shown that this flexible grasping is equivalent to the addition of one more degree of freedom (dof), giving the follower more maneuvering capabilities. In particular, motion commands for the follower are generated by using kinematic redundancy. To show the utility and power of the method, an example system with two PUMA 560 robots carrying a beam is analyzed.

  14. Practical, redundant, failure-tolerant, self-reconfiguring embedded system architecture

    Science.gov (United States)

    Klarer, Paul R.; Hayward, David R.; Amai, Wendy A.

    2006-10-03

    This invention relates to system architectures, specifically failure-tolerant and self-reconfiguring embedded system architectures. The invention provides both a method and architecture for redundancy. There can be redundancy in both software and hardware for multiple levels of redundancy. The invention provides a self-reconfiguring architecture for activating redundant modules whenever other modules fail. The architecture comprises: a communication backbone connected to two or more processors and software modules running on each of the processors. Each software module runs on one processor and resides on one or more of the other processors to be available as a backup module in the event of failure. Each module and backup module reports its status over the communication backbone. If a primary module does not report, its backup module takes over its function. If the primary module becomes available again, the backup module returns to its backup status.

  15. EFFICIENCY OF REDUNDANT QUERY EXECUTION IN MULTI-CHANNEL SERVICE SYSTEMS

    Directory of Open Access Journals (Sweden)

    V. A. Bogatyrev

    2016-03-01

    Full Text Available Subject of Research.The paper deals with analysis of the effectiveness of redundant queries based on untrusted computing in computer systems, represented by multi-channel queuing systems with a common queue. The objective of research is the possibility of increasing the efficiency of service requests while performing redundant copies of requests in different devices of a multi-channel system under conditions of calculations unreliability. The redundant service of requests requires the infallibility of its implementation at least in one of the devices.Method. We have considered estimation of the average time spent in the system with and without the use of redundant requests at the presentation of a simple queuing model of the M / M / n type to analyze the effectiveness of redundant service of requests. Presented evaluation of the average waiting time in the redundant queries is the upper one, since it ignores the possibility of reducing the average waiting time as a result of the spread of the probability of time querying at different devices. The integrated efficiency of redundant service of requests is defined based on the multiplicative index that takes into account the infallibility of calculations and the average time allowance with respect to the maximum tolerated delay of service. Evaluation of error-free computing at reserved queries is received at the requirement of faultless execution of at least one copy of the request. Main Results. We have shown that the reservation of requests gives the gain in efficiency of the system at low demand rate (load. We have defined the boundaries of expediency (efficiency for redundant service of requests. We have shown the possibility of the effectiveness increasing of the adaptive changes in the multiplicity of the reservation of requests, depending on the intensity of the flow of requests. We have found out that the choice of service discipline in information service systems is largely determined by

  16. An overview of adaptive model theory: solving the problems of redundancy, resources, and nonlinear interactions in human movement control.

    Science.gov (United States)

    Neilson, Peter D; Neilson, Megan D

    2005-09-01

    Adaptive model theory (AMT) is a computational theory that addresses the difficult control problem posed by the musculoskeletal system in interaction with the environment. It proposes that the nervous system creates motor maps and task-dependent synergies to solve the problems of redundancy and limited central resources. These lead to the adaptive formation of task-dependent feedback/feedforward controllers able to generate stable, noninteractive control and render nonlinear interactions unobservable in sensory-motor relationships. AMT offers a unified account of how the nervous system might achieve these solutions by forming internal models. This is presented as the design of a simulator consisting of neural adaptive filters based on cerebellar circuitry. It incorporates a new network module that adaptively models (in real time) nonlinear relationships between inputs with changing and uncertain spectral and amplitude probability density functions as is the case for sensory and motor signals.

  17. Palpebral redundancy from hypothyroidism.

    Science.gov (United States)

    Wortsman, J; Wavak, P

    1980-01-01

    A patient is described with disabling palpebral edema. Primary hypothyroidism had been previously diagnosed and treated. Testing of thyroid function revealed persistence of the hypothyroidism. Treatment with L-thyroxine produced normalization of the biochemical parameters and resolution of palpebral edema. The search for hypothyrodism in patients with palpebral redundancy is emphasized.

  18. Parameter identifiability and redundancy: theoretical considerations.

    Directory of Open Access Journals (Sweden)

    Mark P Little

    Full Text Available BACKGROUND: Models for complex biological systems may involve a large number of parameters. It may well be that some of these parameters cannot be derived from observed data via regression techniques. Such parameters are said to be unidentifiable, the remaining parameters being identifiable. Closely related to this idea is that of redundancy, that a set of parameters can be expressed in terms of some smaller set. Before data is analysed it is critical to determine which model parameters are identifiable or redundant to avoid ill-defined and poorly convergent regression. METHODOLOGY/PRINCIPAL FINDINGS: In this paper we outline general considerations on parameter identifiability, and introduce the notion of weak local identifiability and gradient weak local identifiability. These are based on local properties of the likelihood, in particular the rank of the Hessian matrix. We relate these to the notions of parameter identifiability and redundancy previously introduced by Rothenberg (Econometrica 39 (1971 577-591 and Catchpole and Morgan (Biometrika 84 (1997 187-196. Within the widely used exponential family, parameter irredundancy, local identifiability, gradient weak local identifiability and weak local identifiability are shown to be largely equivalent. We consider applications to a recently developed class of cancer models of Little and Wright (Math Biosciences 183 (2003 111-134 and Little et al. (J Theoret Biol 254 (2008 229-238 that generalize a large number of other recently used quasi-biological cancer models. CONCLUSIONS/SIGNIFICANCE: We have shown that the previously developed concepts of parameter local identifiability and redundancy are closely related to the apparently weaker properties of weak local identifiability and gradient weak local identifiability--within the widely used exponential family these concepts largely coincide.

  19. Reliability Analysis and Calibration of Partial Safety Factors for Redundant Structures

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard

    1998-01-01

    Redundancy is important to include in the design and analysis of structural systems. In most codes of practice redundancy is not directly taken into account. In the paper various definitions of a deterministic and reliability based redundancy measure are reviewed. It is described how reundancy can...... be included in the safety system and how partial safety factors can be calibrated. An example is presented illustrating how redundancy is taken into account in the safety system in e.g. the Danish codes. The example shows how partial safety factors can be calibrated to comply with the safety level...

  20. Redundancy Optimization for Error Recovery in Digital Microfluidic Biochips

    DEFF Research Database (Denmark)

    Alistar, Mirela; Pop, Paul; Madsen, Jan

    2015-01-01

    Microfluidic-based biochips are replacing the conventional biochemical analyzers, and are able to integrate all the necessary functions for biochemical analysis. The digital microfluidic biochips are based on the manipulation of liquids not as a continuous flow, but as discrete droplets. Research......Microfluidic-based biochips are replacing the conventional biochemical analyzers, and are able to integrate all the necessary functions for biochemical analysis. The digital microfluidic biochips are based on the manipulation of liquids not as a continuous flow, but as discrete droplets....... Researchers have proposed approaches for the synthesis of digital microfluidic biochips, which, starting from a biochemical application and a given biochip architecture, determine the allocation, resource binding, scheduling, placement and routing of the operations in the application. During the execution...... propose an online recovery strategy, which decides during the execution of the biochemical application the introduction of the redundancy required for fault-tolerance. We consider both time redundancy, i.e., re-executing erroneous operations, and space redundancy, i.e., creating redundant droplets...

  1. Multisensory processing in the redundant-target effect

    DEFF Research Database (Denmark)

    Gondan, Matthias; Niederhaus, Birgit; Rösler, Frank

    2005-01-01

    Participants respond more quickly to two simultaneously presented target stimuli of two different modalities (redundant targets) than would be predicted from their reaction times to the unimodal targets. To examine the neural correlates of this redundant-target effect, event-related potentials...... (ERPs) were recorded to auditory, visual, and bimodal standard and target stimuli presented at two locations (left and right of central fixation). Bimodal stimuli were combinations of two standards, two targets, or a standard and a target, presented either from the same or from different locations...

  2. Research on a six-phase permanent magnet synchronous motor system at dual-redundant and fault tolerant modes in aviation application

    Directory of Open Access Journals (Sweden)

    Xiaolin KUANG

    2017-08-01

    Full Text Available With the development of more/all electrical aircraft technology, an electro-mechanical actuator (EMA is more and more used in an aircraft actuation system. The motor system, as the crucial part of an EMA, usually adopts the redundancy technology or fault tolerance technology to improve the reliability. To compare the performances of these two motor systems, a 10-pole/12-slot six-phase permanent magnet synchronous motor (PMSM is designed with the concentrated single-layer winding, which is able to operate at dual-redundant and fault tolerant modes. Furthermore, the position servo performances of the six-phase PMSM at dual-redundant and fault tolerant modes are analyzed, including the normal and fault conditions. In addition, a variable structure proportional-integral-derivative (PID control strategy is proposed to solve the performance degradation problem caused by phase current saturation. Simulation and experimental results show that the fault tolerant PMSM has a better position servo performance than the dual-redundant PMSM, and the variable structure PID control strategy is able to improve the performance due to phase current saturation.

  3. Quantum Darwinism: Entanglement, branches, and the emergent classicality of redundantly stored quantum information

    International Nuclear Information System (INIS)

    Blume-Kohout, Robin; Zurek, Wojciech H.

    2006-01-01

    We lay a comprehensive foundation for the study of redundant information storage in decoherence processes. Redundancy has been proposed as a prerequisite for objectivity, the defining property of classical objects. We consider two ensembles of states for a model universe consisting of one system and many environments: the first consisting of arbitrary states, and the second consisting of 'singly branching' states consistent with a simple decoherence model. Typical states from the random ensemble do not store information about the system redundantly, but information stored in branching states has a redundancy proportional to the environment's size. We compute the specific redundancy for a wide range of model universes, and fit the results to a simple first-principles theory. Our results show that the presence of redundancy divides information about the system into three parts: classical (redundant); purely quantum; and the borderline, undifferentiated or 'nonredundant', information

  4. Quantum Darwinism: Entanglement, branches, and the emergent classicality of redundantly stored quantum information

    Science.gov (United States)

    Blume-Kohout, Robin; Zurek, Wojciech H.

    2006-06-01

    We lay a comprehensive foundation for the study of redundant information storage in decoherence processes. Redundancy has been proposed as a prerequisite for objectivity, the defining property of classical objects. We consider two ensembles of states for a model universe consisting of one system and many environments: the first consisting of arbitrary states, and the second consisting of “singly branching” states consistent with a simple decoherence model. Typical states from the random ensemble do not store information about the system redundantly, but information stored in branching states has a redundancy proportional to the environment’s size. We compute the specific redundancy for a wide range of model universes, and fit the results to a simple first-principles theory. Our results show that the presence of redundancy divides information about the system into three parts: classical (redundant); purely quantum; and the borderline, undifferentiated or “nonredundant,” information.

  5. Quantum Darwinism Requires an Extra-Theoretical Assumption of Encoding Redundancy

    Science.gov (United States)

    Fields, Chris

    2010-10-01

    Observers restricted to the observation of pointer states of apparatus cannot conclusively demonstrate that the pointer of an apparatus mathcal{A} registers the state of a system of interest S without perturbing S. Observers cannot, therefore, conclusively demonstrate that the states of a system S are redundantly encoded by pointer states of multiple independent apparatus without destroying the redundancy of encoding. The redundancy of encoding required by quantum Darwinism must, therefore, be assumed from outside the quantum-mechanical formalism and without the possibility of experimental demonstration.

  6. A Dynamic Linear Hashing Method for Redundancy Management in Train Ethernet Consist Network

    Directory of Open Access Journals (Sweden)

    Xiaobo Nie

    2016-01-01

    Full Text Available Massive transportation systems like trains are considered critical systems because they use the communication network to control essential subsystems on board. Critical system requires zero recovery time when a failure occurs in a communication network. The newly published IEC62439-3 defines the high-availability seamless redundancy protocol, which fulfills this requirement and ensures no frame loss in the presence of an error. This paper adopts these for train Ethernet consist network. The challenge is management of the circulating frames, capable of dealing with real-time processing requirements, fast switching times, high throughout, and deterministic behavior. The main contribution of this paper is the in-depth analysis it makes of network parameters imposed by the application of the protocols to train control and monitoring system (TCMS and the redundant circulating frames discarding method based on a dynamic linear hashing, using the fastest method in order to resolve all the issues that are dealt with.

  7. Human genetics of infectious diseases: Unique insights into immunological redundancy.

    Science.gov (United States)

    Casanova, Jean-Laurent; Abel, Laurent

    2018-04-01

    For almost any given human-tropic virus, bacterium, fungus, or parasite, the clinical outcome of primary infection is enormously variable, ranging from asymptomatic to lethal infection. This variability has long been thought to be largely determined by the germline genetics of the human host, and this is increasingly being demonstrated to be the case. The number and diversity of known inborn errors of immunity is continually increasing, and we focus here on autosomal and X-linked recessive traits underlying complete deficiencies of the encoded protein. Schematically, four types of infectious phenotype have been observed in individuals with such deficiencies, each providing information about the redundancy of the corresponding human gene, in terms of host defense in natural conditions. The lack of a protein can confer vulnerability to a broad range of microbes in most, if not all patients, through the disruption of a key immunological component. In such cases, the gene concerned is of low redundancy. However, the lack of a protein may also confer vulnerability to a narrow range of microbes, sometimes a single pathogen, and not necessarily in all patients. In such cases, the gene concerned is highly redundant. Conversely, the deficiency may be apparently neutral, conferring no detectable predisposition to infection in any individual. In such cases, the gene concerned is completely redundant. Finally, the lack of a protein may, paradoxically, be advantageous to the host, conferring resistance to one or more infections. In such cases, the gene is considered to display beneficial redundancy. These findings reflect the current state of evolution of humans and microbes, and should not be considered predictive of redundancy, or of a lack of redundancy, in the distant future. Nevertheless, these observations are of potential interest to present-day biologists testing immunological hypotheses experimentally and physicians managing patients with immunological or infectious

  8. Redundancies in Data and their Effect on the Evaluation of Recommendation Systems

    DEFF Research Database (Denmark)

    Basaran, Daniel; Ntoutsi, Eirini; Zimek, Arthur

    2017-01-01

    A collection of datasets crawled from Amazon, “Amazon reviews”, is popular in the evaluation of recommendation systems. These datasets, however, contain redundancies (duplicated recommendations for variants of certain items). These redundancies went unnoticed in earlier use of these datasets...... and thus incurred to a certain extent wrong conclusions in the evaluation of algorithms tested on these datasets. We analyze the nature and amount of these redundancies and their impact on the evaluation of recommendation methods. While the general and obvious conclusion is that redundancies should...

  9. Neural redundancy applied to the parity space for signal validation

    International Nuclear Information System (INIS)

    Mol, Antonio Carlos de Abreu; Pereira, Claudio Marcio Nascimento Abreu; Martinez, Aquilino Senra

    2005-01-01

    The objective of signal validation is to provide more reliable information from the plant sensor data The method presented in this work introduces the concept of neural redundancy and applies it to the space parity method [1] to overcome an inherent deficiency of this method - the determination of the best estimative of the redundant measures when they are inconsistent. The concept of neural redundancy consists on the calculation of a redundancy through neural networks based on the time series of the own state variable. Therefore, neural networks, dynamically trained with the time series, will estimate the current value of the own measure, which will be used as referee of the redundant measures in the parity space. For this purpose the neural network should have the capacity to supply the neural redundancy in real time and with maximum error corresponding to the group deviation. The historical series should be enough to allow the estimate of the next value, during transients and at the same time, it should be optimized to facilitate the retraining of the neural network to each acquisition. In order to have the capacity to reproduce the tendency of the time series even under accident condition, the dynamic training of the neural network privileges the recent points of the time series. The tests accomplished with simulated data of a nuclear plant, demonstrated that this method applied on the parity space method improves the signal validation process. (author)

  10. Neural redundancy applied to the parity space for signal validation

    Energy Technology Data Exchange (ETDEWEB)

    Mol, Antonio Carlos de Abreu; Pereira, Claudio Marcio Nascimento Abreu [Instituto de Engenharia Nuclear (IEN), Rio de Janeiro, RJ (Brazil)]. E-mail: cmnap@ien.gov.br; Martinez, Aquilino Senra [Universidade Federal, Rio de Janeiro, RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia]. E-mail: aquilino@lmp.br

    2005-07-01

    The objective of signal validation is to provide more reliable information from the plant sensor data The method presented in this work introduces the concept of neural redundancy and applies it to the space parity method [1] to overcome an inherent deficiency of this method - the determination of the best estimative of the redundant measures when they are inconsistent. The concept of neural redundancy consists on the calculation of a redundancy through neural networks based on the time series of the own state variable. Therefore, neural networks, dynamically trained with the time series, will estimate the current value of the own measure, which will be used as referee of the redundant measures in the parity space. For this purpose the neural network should have the capacity to supply the neural redundancy in real time and with maximum error corresponding to the group deviation. The historical series should be enough to allow the estimate of the next value, during transients and at the same time, it should be optimized to facilitate the retraining of the neural network to each acquisition. In order to have the capacity to reproduce the tendency of the time series even under accident condition, the dynamic training of the neural network privileges the recent points of the time series. The tests accomplished with simulated data of a nuclear plant, demonstrated that this method applied on the parity space method improves the signal validation process. (author)

  11. Reliability optimization of series–parallel systems with mixed redundancy strategy in subsystems

    International Nuclear Information System (INIS)

    Abouei Ardakan, Mostafa; Zeinal Hamadani, Ali

    2014-01-01

    Traditionally in redundancy allocation problem (RAP), it is assumed that the redundant components are used based on a predefined active or standby strategies. Recently, some studies consider the situation that both active and standby strategies can be used in a specific system. However, these researches assume that the redundancy strategy for each subsystem can be either active or standby and determine the best strategy for these subsystems by using a proper mathematical model. As an extension to this assumption, a novel strategy, that is a combination of traditional active and standby strategies, is introduced. The new strategy is called mixed strategy which uses both active and cold-standby strategies in one subsystem simultaneously. Therefore, the problem is to determine the component type, redundancy level, number of active and cold-standby units for each subsystem in order to maximize the system reliability. To have a more practical model, the problem is formulated with imperfect switching of cold-standby redundant components and k-Erlang time-to-failure (TTF) distribution. As the optimization of RAP belongs to NP-hard class of problems, a genetic algorithm (GA) is developed. The new strategy and proposed GA are implemented on a well-known test problem in the literature which leads to interesting results. - Highlights: • In this paper the redundancy allocation problem (RAP) for a series–parallel system is considered. • Traditionally there are two main strategies for redundant component namely active and standby. • In this paper a new redundancy strategy which is called “Mixed” redundancy strategy is introduced. • Computational experiments demonstrate that implementing the new strategy lead to interesting results

  12. Techno-Economic Assessment of Redundancy Systems for a Cogeneration Plant

    Directory of Open Access Journals (Sweden)

    Majid Mohd Amin Abd

    2014-07-01

    Full Text Available The use of distributed power generation has advantage as well as disadvantage. One of the disadvantages is that the plant requires a dependable redundancy system to provide back up of power during failure of its power generation equipment. This paper presents a study on techno-economic assessment of redundancy systems for a cogeneration plant. Three redundancy systems were investigated; using public utility, generator set and gas turbine as back up during failures. Results from the analysis indicate that using public utility provides technical as well as economic advantages in comparison to using generator set or turbine as back up. However, the economic advantage of the public utility depends on the frequency of failures the plant will experience as well on the maximum demand charge. From the break even analysis of the understudied plant, if the number of failures exceeds 3 failures per year for the case of maximum demand charge of RM56.80, it is more economical to install a generator set as redundancy. The study will be useful for the co-generator operators to evaluate the feasibility of redundancy systems.

  13. 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 ...

  14. Image Registration Using Redundant Wavelet Transforms

    National Research Council Canada - National Science Library

    Brown, Richard

    2001-01-01

    .... In our research, we present a fundamentally new wavelet-based registration algorithm utilizing redundant transforms and a masking process to suppress the adverse effects of noise and improve processing efficiency...

  15. Program management aid for redundancy selection and operational guidelines

    Science.gov (United States)

    Hodge, P. W.; Davis, W. L.; Frumkin, B.

    1972-01-01

    Although this criterion was developed specifically for use on the shuttle program, it has application to many other multi-missions programs (i.e. aircraft or mechanisms). The methodology employed is directly applicable even if the tools (nomographs and equations) are for mission peculiar cases. The redundancy selection criterion was developed to insure that both the design and operational cost impacts (life cycle costs) were considered in the selection of the quantity of operational redundancy. These tools were developed as aids in expediting the decision process and not intended as the automatic decision maker. This approach to redundancy selection is unique in that it enables a pseudo systems analysis to be performed on an equipment basis without waiting for all designs to be hardened.

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

    International Nuclear Information System (INIS)

    Coelho, Leandro dos Santos

    2009-01-01

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

  17. Conflicts versus analytical redundancy relations: a comparative analysis of the model based diagnosis approach from the artificial intelligence and automatic control perspectives.

    Science.gov (United States)

    Cordier, Marie-Odile; Dague, Philippe; Lévy, François; Montmain, Jacky; Staroswiecki, Marcel; Travé-Massuyès, Louise

    2004-10-01

    Two distinct and parallel research communities have been working along the lines of the model-based diagnosis approach: the fault detection and isolation (FDI) community and the diagnostic (DX) community that have evolved in the fields of automatic control and artificial intelligence, respectively. This paper clarifies and links the concepts and assumptions that underlie the FDI analytical redundancy approach and the DX consistency-based logical approach. A formal framework is proposed in order to compare the two approaches and the theoretical proof of their equivalence together with the necessary and sufficient conditions is provided.

  18. SIMULATION MODEL FOR DESIGN SUPPORT OF INFOCOMM REDUNDANT SYSTEMS

    Directory of Open Access Journals (Sweden)

    V. A. Bogatyrev

    2016-09-01

    Full Text Available Subject of Research. The paper deals with the effectiveness of multipath transfer of request copies through the network and their redundant service without the use of laborious analytical modeling. The model and support tools for the design of highly reliable distributed systems based on simulation modeling have been created. Method. The effectiveness of many variants of service organization and delivery through the network to the query servers is formed and analyzed. Options for providing redundant service and delivery via the network to the servers of request copies are also considered. The choice of variants for the distribution and service of requests is carried out taking into account the criticality of queries to the time of their stay in the system. The request is considered successful if at least one of its copies is accurately delivered to the working server, ready to service the request received through a network, if it is fulfilled in the set time. Efficiency analysis of the redundant transmission and service of requests is based on the model built in AnyLogic 7 simulation environment. Main Results. Simulation experiments based on the proposed models have shown the effectiveness of redundant transmission of copies of queries (packets to the servers in the cluster through multiple paths with redundant service of request copies by a group of servers in the cluster. It is shown that this solution allows increasing the probability of exact execution of at least one copy of the request within the required time. We have carried out efficiency evaluation of destruction of outdated request copies in the queues of network nodes and the cluster. We have analyzed options for network implementation of multipath transfer of request copies to the servers in the cluster over disjoint paths, possibly different according to the number of their constituent nodes. Practical Relevance. The proposed simulation models can be used when selecting the optimal

  19. Redundancy Elimination in DTN via ACK Mechanism

    Directory of Open Access Journals (Sweden)

    Xiqing Zhang

    2015-08-01

    Full Text Available The traditional routing protocols for delay tolerant networks (DTN usually take the strategy of spreading multiple copies of one message to the networks. When one copy reaches destination, the transmission of other copies not only waste the bandwidth but also deprive other messages of the opportunities for transmission. This paper brings up a mechanism to eliminate the redundant copies. By adding an acknowledge field to the packet header to delete redundant copies, it can degrade the network overhead while improve the delivery ratio. Simulation results confirm that the proposed method can improve the performance of epidemic and Spray and Wait routing protocol.

  20. Self-checking in a logic protection system using a redundant computer structure

    International Nuclear Information System (INIS)

    Darier, P.; Lallement, D.

    1978-01-01

    The logic protection system described has a parallel and redundant computer structure. Each assembly consists of an analog and digital acquisition module, a processing unit and a simple and reliable logical decision device adapted to the redundancy of the system (two-out-of-three or two-out-of-four). Each processing unit monitors all the detection units, processes the values received and works out the corresponding decisions. The decisions are collated in the final stage in a majority decision element which sets the protective action in motion. At all levels the quality of data transmission and validity of processing are tested in order that the best strategy may be applied in the event of damage to the system. Several self-checking techniques were used: they include a set of electronic test modules connected to the processing unit, on-line system testing and control software and time control devices which provide a final verification of the overall operation of the system. Self-checking and test operations are performed regularly throughout surveillance cycles. Problems of fault detection and of protection against the effects of faults are examined from the aspect of hardware and software. (author)

  1. An improved method for calculating self-motion coordinates for redundant manipulators

    International Nuclear Information System (INIS)

    Reister, D.B.

    1997-04-01

    For a redundant manipulator, the objective of redundancy resolution is to follow a specified path in Cartesian space and simultaneously perform another task (for example, maximize an objective function or avoid obstacles) at every point along the path. The conventional methods have several drawbacks: a new function must be defined for each task, the extended Jacobian can be singular, closed cycles in Cartesian space may not yield closed cycles in joint space, and the objective is point-wise redundancy resolution (to determine a single point in joint space for each point in Cartesian space). The author divides the redundancy resolution problem into two parts: (1) calculate self-motion coordinates for all possible positions of a manipulator at each point along a Cartesian path and (2) determination of optimal self-motion coordinates that maximize an objective function along the path. This paper will discuss the first part of the problem. The path-wise approach overcomes all of the drawbacks of conventional redundancy resolution methods: no need to define a new function for each task, extended Jacobian cannot be singular, and closed cycles in extended Cartesian space will yield closed cycles in joint space

  2. A comparison of Heuristic method and Llewellyn’s rules for identification of redundant constraints

    Science.gov (United States)

    Estiningsih, Y.; Farikhin; Tjahjana, R. H.

    2018-03-01

    Important techniques in linear programming is modelling and solving practical optimization. Redundant constraints are consider for their effects on general linear programming problems. Identification and reduce redundant constraints are for avoidance of all the calculations associated when solving an associated linear programming problems. Many researchers have been proposed for identification redundant constraints. This paper a compararison of Heuristic method and Llewellyn’s rules for identification of redundant constraints.

  3. Kinematics analysis of a novel planar parallel manipulator with kinematic redundancy

    Energy Technology Data Exchange (ETDEWEB)

    Qu, Haibo; Guo, Sheng [Beijing Jiaotong University, Beijing (China)

    2017-04-15

    In this paper, a novel planar parallel manipulator with kinematic redundancy is proposed. First, the Degrees of freedom (DOF) of the whole parallel manipulator and the Relative DOF (RDOF) between the moving platform and fixed base are studied. The results indicate that the proposed mechanism is kinematically redundant. Then, the kinematics, Jacobian matrices and workspace of this proposed parallel manipulator with kinematic redundancy are analyzed. Finally, the statics simulation of the proposed parallel manipulator is performed. The obtained stress and displacement distribution can be used to determine the easily destroyed place in the mechanism configurations.

  4. Kinematics analysis of a novel planar parallel manipulator with kinematic redundancy

    International Nuclear Information System (INIS)

    Qu, Haibo; Guo, Sheng

    2017-01-01

    In this paper, a novel planar parallel manipulator with kinematic redundancy is proposed. First, the Degrees of freedom (DOF) of the whole parallel manipulator and the Relative DOF (RDOF) between the moving platform and fixed base are studied. The results indicate that the proposed mechanism is kinematically redundant. Then, the kinematics, Jacobian matrices and workspace of this proposed parallel manipulator with kinematic redundancy are analyzed. Finally, the statics simulation of the proposed parallel manipulator is performed. The obtained stress and displacement distribution can be used to determine the easily destroyed place in the mechanism configurations

  5. Hybrid online sensor error detection and functional redundancy for systems with time-varying parameters.

    Science.gov (United States)

    Feng, Jianyuan; Turksoy, Kamuran; Samadi, Sediqeh; Hajizadeh, Iman; Littlejohn, Elizabeth; Cinar, Ali

    2017-12-01

    Supervision and control systems rely on signals from sensors to receive information to monitor the operation of a system and adjust manipulated variables to achieve the control objective. However, sensor performance is often limited by their working conditions and sensors may also be subjected to interference by other devices. Many different types of sensor errors such as outliers, missing values, drifts and corruption with noise may occur during process operation. A hybrid online sensor error detection and functional redundancy system is developed to detect errors in online signals, and replace erroneous or missing values detected with model-based estimates. The proposed hybrid system relies on two techniques, an outlier-robust Kalman filter (ORKF) and a locally-weighted partial least squares (LW-PLS) regression model, which leverage the advantages of automatic measurement error elimination with ORKF and data-driven prediction with LW-PLS. The system includes a nominal angle analysis (NAA) method to distinguish between signal faults and large changes in sensor values caused by real dynamic changes in process operation. The performance of the system is illustrated with clinical data continuous glucose monitoring (CGM) sensors from people with type 1 diabetes. More than 50,000 CGM sensor errors were added to original CGM signals from 25 clinical experiments, then the performance of error detection and functional redundancy algorithms were analyzed. The results indicate that the proposed system can successfully detect most of the erroneous signals and substitute them with reasonable estimated values computed by functional redundancy system.

  6. A redundancy-removing feature selection algorithm for nominal data

    Directory of Open Access Journals (Sweden)

    Zhihua Li

    2015-10-01

    Full Text Available No order correlation or similarity metric exists in nominal data, and there will always be more redundancy in a nominal dataset, which means that an efficient mutual information-based nominal-data feature selection method is relatively difficult to find. In this paper, a nominal-data feature selection method based on mutual information without data transformation, called the redundancy-removing more relevance less redundancy algorithm, is proposed. By forming several new information-related definitions and the corresponding computational methods, the proposed method can compute the information-related amount of nominal data directly. Furthermore, by creating a new evaluation function that considers both the relevance and the redundancy globally, the new feature selection method can evaluate the importance of each nominal-data feature. Although the presented feature selection method takes commonly used MIFS-like forms, it is capable of handling high-dimensional datasets without expensive computations. We perform extensive experimental comparisons of the proposed algorithm and other methods using three benchmarking nominal datasets with two different classifiers. The experimental results demonstrate the average advantage of the presented algorithm over the well-known NMIFS algorithm in terms of the feature selection and classification accuracy, which indicates that the proposed method has a promising performance.

  7. Learning contrast-invariant cancellation of redundant signals in neural systems.

    Directory of Open Access Journals (Sweden)

    Jorge F Mejias

    Full Text Available Cancellation of redundant information is a highly desirable feature of sensory systems, since it would potentially lead to a more efficient detection of novel information. However, biologically plausible mechanisms responsible for such selective cancellation, and especially those robust to realistic variations in the intensity of the redundant signals, are mostly unknown. In this work, we study, via in vivo experimental recordings and computational models, the behavior of a cerebellar-like circuit in the weakly electric fish which is known to perform cancellation of redundant stimuli. We experimentally observe contrast invariance in the cancellation of spatially and temporally redundant stimuli in such a system. Our model, which incorporates heterogeneously-delayed feedback, bursting dynamics and burst-induced STDP, is in agreement with our in vivo observations. In addition, the model gives insight on the activity of granule cells and parallel fibers involved in the feedback pathway, and provides a strong prediction on the parallel fiber potentiation time scale. Finally, our model predicts the existence of an optimal learning contrast around 15% contrast levels, which are commonly experienced by interacting fish.

  8. Does functional redundancy stabilize fish communities?

    DEFF Research Database (Denmark)

    Rice, Jake; Daan, Niels; Gislason, Henrik

    2012-01-01

    Functional redundancy is a community property thought to contribute to ecosystem resilience. It is argued that trophic (or other) functional groups with more species have more linkages and opportunities to buffer variation in abundance of individual species. We explored this concept with a 30‐year...... time‐series of data on 83 species sampled in the International Bottom Trawl Survey. Our results were consistent with the hypothesis that functional redundancy leads to more stable (and by inference more resilient) communities. Over the time‐series trophic groups (assigned by diet, size (Lmax) group......, or both factors) with more species had lower coefficients of variation (CVs) in abundance and biomass than did trophic groups with fewer species. These findings are also consistent with Bernoulli’s Law of Large Numbers, a rule that does not require complex ecological and evolutionary processes to produce...

  9. A two-stage approach for managing actuators redundancy and its application to fault tolerant flight control

    Directory of Open Access Journals (Sweden)

    Zhong Lunlong

    2015-04-01

    Full Text Available In safety-critical systems such as transportation aircraft, redundancy of actuators is introduced to improve fault tolerance. How to make the best use of remaining actuators to allow the system to continue achieving a desired operation in the presence of some actuators failures is the main subject of this paper. Considering that many dynamical systems, including flight dynamics of a transportation aircraft, can be expressed as an input affine nonlinear system, a new state representation is adopted here where the output dynamics are related with virtual inputs associated with the intended operation. This representation, as well as the distribution matrix associated with the effectiveness of the remaining operational actuators, allows us to define different levels of fault tolerant governability with respect to actuators’ failures. Then, a two-stage control approach is developed, leading first to the inversion of the output dynamics to get nominal values for the virtual inputs and then to the solution of a linear quadratic (LQ problem to compute the solicitation of each operational actuator. The proposed approach is applied to the control of a transportation aircraft which performs a stabilized roll maneuver while a partial failure appears. Two fault scenarios are considered and the resulting performance of the proposed approach is displayed and discussed.

  10. On Planning of FTTH Access Networks with and without Redundancy

    DEFF Research Database (Denmark)

    Riaz, M. Tahir; Haraldsson, Gustav; Gutierrez Lopez, Jose Manuel

    2010-01-01

    This paper presents a planning analysis of FTTH access network with and without redundancy. Traditionally, access networks are planned only without redundancy, which is mainly due to lowering the cost of deployment. As fiber optics provide a huge amount of capacity, more and more services are being...... offered on a single fiber connection. As a single point of failure in fiber connection can cause multiple service deprivation therefore redundancy is very crucial. In this work, an automated planning model was used to test different scenarios of implementation. A cost estimation is presented in terms...... of digging and amount of fiber used. Three topologies, including the traditional one “tree topology”, were test with combination of various passive optical technologies....

  11. Multi-objective reliability redundancy allocation in an interval environment using particle swarm optimization

    International Nuclear Information System (INIS)

    Zhang, Enze; Chen, Qingwei

    2016-01-01

    Most of the existing works addressing reliability redundancy allocation problems are based on the assumption of fixed reliabilities of components. In real-life situations, however, the reliabilities of individual components may be imprecise, most often given as intervals, under different operating or environmental conditions. This paper deals with reliability redundancy allocation problems modeled in an interval environment. An interval multi-objective optimization problem is formulated from the original crisp one, where system reliability and cost are simultaneously considered. To render the multi-objective particle swarm optimization (MOPSO) algorithm capable of dealing with interval multi-objective optimization problems, a dominance relation for interval-valued functions is defined with the help of our newly proposed order relations of interval-valued numbers. Then, the crowding distance is extended to the multi-objective interval-valued case. Finally, the effectiveness of the proposed approach has been demonstrated through two numerical examples and a case study of supervisory control and data acquisition (SCADA) system in water resource management. - Highlights: • We model the reliability redundancy allocation problem in an interval environment. • We apply the particle swarm optimization directly on the interval values. • A dominance relation for interval-valued multi-objective functions is defined. • The crowding distance metric is extended to handle imprecise objective functions.

  12. Analysis of functional redundancies within the Arabidopsis TCP transcription factor family

    NARCIS (Netherlands)

    Danisman, S.; Dijk, van A.D.J.; Bimbo, A.; Wal, van der F.; Hennig, L.; Folter, de S.; Angenent, G.C.; Immink, R.G.H.

    2013-01-01

    Analyses of the functions of TEOSINTE-LIKE1, CYCLOIDEA, and ROLIFERATING CELL FACTOR1 (TCP) transcription factors have been hampered by functional redundancy between its individual members. In general, putative functionally redundant genes are predicted based on sequence similarity and confirmed by

  13. Equivalence of velocity-level and acceleration-level redundancy-resolution of manipulators

    International Nuclear Information System (INIS)

    Cai Binghuang; Zhang Yunong

    2009-01-01

    The equivalence of velocity-level and acceleration-level redundancy resolution of robot manipulators is investigated in this Letter. Theoretical analysis based on gradient-descent method and computer simulations based on PUMA560 robot manipulator both demonstrate the equivalence of redundancy-resolution schemes at different levels.

  14. Reliability optimization of series-parallel systems with a choice of redundancy strategies using a genetic algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Tavakkoli-Moghaddam, R. [Department of Industrial Engineering, Faculty of Engineering, University of Tehran, P.O. Box 11365/4563, Tehran (Iran, Islamic Republic of); Department of Mechanical Engineering, The University of British Columbia, Vancouver (Canada)], E-mail: tavakoli@ut.ac.ir; Safari, J. [Department of Industrial Engineering, Science and Research Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of)], E-mail: jalalsafari@pideco.com; Sassani, F. [Department of Mechanical Engineering, The University of British Columbia, Vancouver (Canada)], E-mail: sassani@mech.ubc.ca

    2008-04-15

    This paper proposes a genetic algorithm (GA) for a redundancy allocation problem for the series-parallel system when the redundancy strategy can be chosen for individual subsystems. Majority of the solution methods for the general redundancy allocation problems assume that the redundancy strategy for each subsystem is predetermined and fixed. In general, active redundancy has received more attention in the past. However, in practice both active and cold-standby redundancies may be used within a particular system design and the choice of the redundancy strategy becomes an additional decision variable. Thus, the problem is to select the best redundancy strategy, component, and redundancy level for each subsystem in order to maximize the system reliability under system-level constraints. This belongs to the NP-hard class of problems. Due to its complexity, it is so difficult to optimally solve such a problem by using traditional optimization tools. It is demonstrated in this paper that GA is an efficient method for solving this type of problems. Finally, computational results for a typical scenario are presented and the robustness of the proposed algorithm is discussed.

  15. Reliability optimization of series-parallel systems with a choice of redundancy strategies using a genetic algorithm

    International Nuclear Information System (INIS)

    Tavakkoli-Moghaddam, R.; Safari, J.; Sassani, F.

    2008-01-01

    This paper proposes a genetic algorithm (GA) for a redundancy allocation problem for the series-parallel system when the redundancy strategy can be chosen for individual subsystems. Majority of the solution methods for the general redundancy allocation problems assume that the redundancy strategy for each subsystem is predetermined and fixed. In general, active redundancy has received more attention in the past. However, in practice both active and cold-standby redundancies may be used within a particular system design and the choice of the redundancy strategy becomes an additional decision variable. Thus, the problem is to select the best redundancy strategy, component, and redundancy level for each subsystem in order to maximize the system reliability under system-level constraints. This belongs to the NP-hard class of problems. Due to its complexity, it is so difficult to optimally solve such a problem by using traditional optimization tools. It is demonstrated in this paper that GA is an efficient method for solving this type of problems. Finally, computational results for a typical scenario are presented and the robustness of the proposed algorithm is discussed

  16. Fault detection in multiply-redundant measurement systems via sequential testing

    International Nuclear Information System (INIS)

    Ray, A.

    1988-01-01

    The theory and application of a sequential test procedure for fault detection and isolation. The test procedure is suited for development of intelligent instrumentation in strategic processes like aircraft and nuclear plants where redundant measurements are usually available for individual critical variables. The test procedure consists of: (1) a generic redundancy management procedure which is essentially independent of the fault detection strategy and measurement noise statistics, and (2) a modified version of sequential probability ratio test algorithm for fault detection and isolation, which functions within the framework of this redundancy management procedure. The sequential test procedure is suitable for real-time applications using commercially available microcomputers and its efficacy has been verified by online fault detection in an operating nuclear reactor. 15 references

  17. Functional Redundancy of ERK1 and ERK2 MAP Kinases during Development

    Directory of Open Access Journals (Sweden)

    Christophe Frémin

    2015-08-01

    Full Text Available ERK1 and ERK2 are the effector kinases of the ERK1/2 MAP-kinase signaling pathway, which plays a central role in transducing signals controlling cell proliferation, differentiation, and survival. Deregulated activity of the ERK1/2 pathway is linked to a group of developmental syndromes and contributes to the pathogenesis of various human diseases. One fundamental question that remains unaddressed is whether ERK1 and ERK2 have evolved unique physiological functions or whether they are used redundantly to reach a threshold of global ERK activity. Here, we show that the extent of development of the mouse placenta and embryo bearing different combinations of Erk1 and Erk2 alleles is strictly correlated with total ERK1/2 activity. We further demonstrate that transgenic expression of ERK1 fully rescues the embryonic and placental developmental defects associated with the loss of ERK2. We conclude that ERK1 and ERK2 exert redundant functions in mouse development.

  18. A Comparison of Routing Protocol for WSNs: Redundancy Based Approach A Comparison of Routing Protocol for WSNs: Redundancy Based Approach

    Directory of Open Access Journals (Sweden)

    Anand Prakash

    2014-03-01

    Full Text Available Wireless Sensor Networks (WSNs with their dynamic applications gained a tremendous attention of researchers. Constant monitoring of critical situations attracted researchers to utilize WSNs at vast platforms. The main focus in WSNs is to enhance network localization as much as one could, for efficient and optimal utilization of resources. Different approaches based upon redundancy are proposed for optimum functionality. Localization is always related with redundancy of sensor nodes deployed at remote areas for constant and fault tolerant monitoring. In this work, we propose a comparison of classic flooding and the gossip protocol for homogenous networks which enhances stability and throughput quiet significantly.  

  19. Minister wants age balance to play greater role in redundancy selection

    NARCIS (Netherlands)

    Grünell, M.

    2004-01-01

    In May 2004, the Dutch Minister of Social Affairs proposed changes to the statutory rules on selection for redundancy, with less emphasis on the last in, first out seniority-based principle and a greater focus on distributing the redundancies between employees of different ages. The social partners

  20. Intraguild predation reduces redundancy of predator species in multiple predator assemblage.

    Science.gov (United States)

    Griffen, Blaine D; Byers, James E

    2006-07-01

    1. Interference between predator species frequently decreases predation rates, lowering the risk of predation for shared prey. However, such interference can also occur between conspecific predators. 2. Therefore, to understand the importance of predator biodiversity and the degree that predator species can be considered functionally interchangeable, we determined the degree of additivity and redundancy of predators in multiple- and single-species combinations. 3. We show that interference between two invasive species of predatory crabs, Carcinus maenas and Hemigrapsus sanguineus, reduced the risk of predation for shared amphipod prey, and had redundant per capita effects in most multiple- and single-species predator combinations. 4. However, when predator combinations with the potential for intraguild predation were examined, predator interference increased and predator redundancy decreased. 5. Our study indicates that trophic structure is important in determining how the effects of predator species combine and demonstrates the utility of determining the redundancy, as well as the additivity, of multiple predator species.

  1. Efficient exact optimization of multi-objective redundancy allocation problems in series-parallel systems

    International Nuclear Information System (INIS)

    Cao, Dingzhou; Murat, Alper; Chinnam, Ratna Babu

    2013-01-01

    This paper proposes a decomposition-based approach to exactly solve the multi-objective Redundancy Allocation Problem for series-parallel systems. Redundancy allocation problem is a form of reliability optimization and has been the subject of many prior studies. The majority of these earlier studies treat redundancy allocation problem as a single objective problem maximizing the system reliability or minimizing the cost given certain constraints. The few studies that treated redundancy allocation problem as a multi-objective optimization problem relied on meta-heuristic solution approaches. However, meta-heuristic approaches have significant limitations: they do not guarantee that Pareto points are optimal and, more importantly, they may not identify all the Pareto-optimal points. In this paper, we treat redundancy allocation problem as a multi-objective problem, as is typical in practice. We decompose the original problem into several multi-objective sub-problems, efficiently and exactly solve sub-problems, and then systematically combine the solutions. The decomposition-based approach can efficiently generate all the Pareto-optimal solutions for redundancy allocation problems. Experimental results demonstrate the effectiveness and efficiency of the proposed method over meta-heuristic methods on a numerical example taken from the literature.

  2. A novel redundant INS based on triple rotary inertial measurement units

    Science.gov (United States)

    Chen, Gang; Li, Kui; Wang, Wei; Li, Peng

    2016-10-01

    Accuracy and reliability are two key performances of inertial navigation system (INS). Rotation modulation (RM) can attenuate the bias of inertial sensors and make it possible for INS to achieve higher navigation accuracy with lower-class sensors. Therefore, the conflict between the accuracy and cost of INS can be eased. Traditional system redundancy and recently researched sensor redundancy are two primary means to improve the reliability of INS. However, how to make the best use of the redundant information from redundant sensors hasn’t been studied adequately, especially in rotational INS. This paper proposed a novel triple rotary unit strapdown inertial navigation system (TRUSINS), which combines RM and sensor redundancy design to enhance the accuracy and reliability of rotational INS. Each rotary unit independently rotates to modulate the errors of two gyros and two accelerometers. Three units can provide double sets of measurements along all three axes of body frame to constitute a couple of INSs which make TRUSINS redundant. Experiments and simulations based on a prototype which is made up of six fiber-optic gyros with drift stability of 0.05° h-1 show that TRUSINS can achieve positioning accuracy of about 0.256 n mile h-1, which is ten times better than that of a normal non-rotational INS with the same level inertial sensors. The theoretical analysis and the experimental results show that due to the advantage of the innovative structure, the designed fault detection and isolation (FDI) strategy can tolerate six sensor faults at most, and is proved to be effective and practical. Therefore, TRUSINS is particularly suitable and highly beneficial for the applications where high accuracy and high reliability is required.

  3. Objective past of a quantum universe: Redundant records of consistent histories

    Science.gov (United States)

    Riedel, C. Jess; Zurek, Wojciech H.; Zwolak, Michael

    2016-03-01

    Motivated by the advances of quantum Darwinism and recognizing the role played by redundancy in identifying the small subset of quantum states with resilience characteristic of objective classical reality, we explore the implications of redundant records for consistent histories. The consistent histories formalism is a tool for describing sequences of events taking place in an evolving closed quantum system. A set of histories is consistent when one can reason about them using Boolean logic, i.e., when probabilities of sequences of events that define histories are additive. However, the vast majority of the sets of histories that are merely consistent are flagrantly nonclassical in other respects. This embarras de richesses (known as the set selection problem) suggests that one must go beyond consistency to identify how the classical past arises in our quantum universe. The key intuition we follow is that the records of events that define the familiar objective past are inscribed in many distinct systems, e.g., subsystems of the environment, and are accessible locally in space and time to observers. We identify histories that are not just consistent but redundantly consistent using the partial-trace condition introduced by Finkelstein as a bridge between histories and decoherence. The existence of redundant records is a sufficient condition for redundant consistency. It selects, from the multitude of the alternative sets of consistent histories, a small subset endowed with redundant records characteristic of the objective classical past. The information about an objective history of the past is then simultaneously within reach of many, who can independently reconstruct it and arrive at compatible conclusions in the present.

  4. SEU-hardened silicon bipolar and GaAs MESFET SRAM cells using local redundancy techniques

    International Nuclear Information System (INIS)

    Hauser, J.R.

    1992-01-01

    Silicon bipolar and GaAs FET SRAM's have proven to be more difficult to harden with respect to single-event upset mechanisms than have silicon CMOS SRAM's. This is a fundamental property of bipolar and JFET or MESFET device technologies which do not have a high-impedance, nonactive isolation between the control electrode and the current or voltage being controlled. All SEU circuit level hardening techniques applied at the local level must use some type of information storage redundancy so that information loss on one node due to an SEU event can be recovered from information stored elsewhere in the cell. In CMOS technologies, this can be achieved by the use of simple cross-coupling resistors, whereas in bipolar and FET technologies, no such simple approach is possible. Several approaches to the use of local redundancy in bipolar and FET technologies are discussed in this paper. At the expense of increased cell complexity and increased power consumption and write time, several approaches are capable of providing complete SEU hardness at the local cell level

  5. Strategies for redundancy resolution of dual-arm systems with passive elements for tank waste removal

    International Nuclear Information System (INIS)

    Dubey, R.

    1997-01-01

    The work described in this paper focuses on the coordination and control of two manipulators coupled by passive elements operating in a confined space. An example of one such system is the hardware used for the environmental response treatability study funded by the Department of Energy at Oak Ridge National Laboratory (ORNL). The motivation for this project is to establish the methodology necessary to extract large volumes of hazardous waste from underground storage facilities. The hardware used at ORNL consists of two long-reach manipulators. The first robot, the Modified Light Duty Utility Arm (MLDUA), is an 8-degree-of-freedom long-reach manipulator. The second arm, the Hose Management Arm (HMA), has two active degrees-of-freedom and provides hardware to break up and extract materials from the tank. Current strategies call for the MLDUA to grasp a combined sluicing end-effector attached, by a long flexible hose, to the HMA. The MLDUA will then move the combined system through the waste, extracting material. This paper describes many of the issues related to redundancy resolution and the coordinated control of these two robots. First, the authors provide a brief outline of the project and the existing hardware. This is followed by a description of existing redundancy resolution techniques and the impact redundancy has on the success of the project. Finally, preliminary simulation results show the effect cooperative control has on the level of forces generated between the dual-arm systems when coupled by an elastic exhaust hose. These results show a significant reduction in forces when both arms are active and have a combined manipulation strategy

  6. Strategies for redundancy resolution of dual-arm systems with passive elements for tank waste removal

    Energy Technology Data Exchange (ETDEWEB)

    Dubey, R. [Univ. of Tennessee, Knoxville, TN (United States). Dept. of Mechanical Engineering; Love, L.J. [Oak Ridge Inst. for Science and Education, TN (United States)

    1997-03-01

    The work described in this paper focuses on the coordination and control of two manipulators coupled by passive elements operating in a confined space. An example of one such system is the hardware used for the environmental response treatability study funded by the Department of Energy at Oak Ridge National Laboratory (ORNL). The motivation for this project is to establish the methodology necessary to extract large volumes of hazardous waste from underground storage facilities. The hardware used at ORNL consists of two long-reach manipulators. The first robot, the Modified Light Duty Utility Arm (MLDUA), is an 8-degree-of-freedom long-reach manipulator. The second arm, the Hose Management Arm (HMA), has two active degrees-of-freedom and provides hardware to break up and extract materials from the tank. Current strategies call for the MLDUA to grasp a combined sluicing end-effector attached, by a long flexible hose, to the HMA. The MLDUA will then move the combined system through the waste, extracting material. This paper describes many of the issues related to redundancy resolution and the coordinated control of these two robots. First, the authors provide a brief outline of the project and the existing hardware. This is followed by a description of existing redundancy resolution techniques and the impact redundancy has on the success of the project. Finally, preliminary simulation results show the effect cooperative control has on the level of forces generated between the dual-arm systems when coupled by an elastic exhaust hose. These results show a significant reduction in forces when both arms are active and have a combined manipulation strategy.

  7. Developmental changes in children’s processing of redundant modifiers in definite object descriptions

    Directory of Open Access Journals (Sweden)

    Ruud Koolen

    2016-12-01

    Full Text Available This paper investigates developmental changes in children’s processing of redundant information in definite object descriptions. In two experiments, children of two age groups (six or seven, and nine or ten years old were presented with pictures of sweets. In the first experiment (pairwise comparison, two identical sweets were shown, and one of these was described with a redundant modifier. After the description, the children had to indicate the sweet they preferred most in a forced-choice task. In the second experiment (graded rating, only one sweet was shown, which was described with a redundant color modifier in half of the cases (e.g., the blue sweet and in the other half of the cases simply as the sweet. This time, the children were asked to indicate on a 5-point rating scale to what extent they liked the sweets. In both experiments, the results showed that the younger children had a preference for the sweets described with redundant information, while redundant information did not have an effect on the preferences for the older children. These results imply that children are learning to distinguish between situations in which redundant information carries an implicature and situations in which this is not the case.

  8. On the value of redundancy subject to common-cause failures: Toward the resolution of an on-going debate

    International Nuclear Information System (INIS)

    Hoepfer, V.M.; Saleh, J.H.; Marais, K.B.

    2009-01-01

    Common-cause failures (CCF) are one of the more critical and challenging issues for system reliability and risk analyses. Academic interest in modeling CCF, and more broadly in modeling dependent failures, has steadily grown over the years in the number of publications as well as in the sophistication of the analytical tools used. In the past few years, several influential articles have shed doubts on the relevance of redundancy arguing that 'redundancy backfires' through common-cause failures, and that the latter dominate unreliability, thus defeating the purpose of redundancy. In this work, we take issue with some of the results of these publications. In their stead, we provide a nuanced perspective on the (contingent) value of redundancy subject to common-cause failures. First, we review the incremental reliability and MTTF provided by redundancy subject to common-cause failures. Second, we introduce the concept and develop the analytics of the 'redundancy-relevance boundary': we propose this redundancy-relevance boundary as a design-aid tool that provides an answer to the following question: what level of redundancy is relevant or advantageous given a varying prevalence of common-cause failures? We investigate the conditions under which different levels of redundancy provide an incremental MTTF over that of the single component in the face of common-cause failures. Recognizing that redundancy comes at a cost, we also conduct a cost-benefit analysis of redundancy subject to common-cause failures, and demonstrate how this analysis modifies the redundancy-relevance boundary. We show how the value of redundancy is contingent on the prevalence of common-cause failures, the redundancy level considered, and the monadic cost-benefit ratio. Finally we argue that general unqualified criticism of redundancy is misguided, and efforts are better spent for example on understanding and mitigating the potential sources of common-cause failures rather than deriding the concept

  9. A novel redundant INS based on triple rotary inertial measurement units

    International Nuclear Information System (INIS)

    Chen, Gang; Li, Kui; Wang, Wei; Li, Peng

    2016-01-01

    Accuracy and reliability are two key performances of inertial navigation system (INS). Rotation modulation (RM) can attenuate the bias of inertial sensors and make it possible for INS to achieve higher navigation accuracy with lower-class sensors. Therefore, the conflict between the accuracy and cost of INS can be eased. Traditional system redundancy and recently researched sensor redundancy are two primary means to improve the reliability of INS. However, how to make the best use of the redundant information from redundant sensors hasn’t been studied adequately, especially in rotational INS. This paper proposed a novel triple rotary unit strapdown inertial navigation system (TRUSINS), which combines RM and sensor redundancy design to enhance the accuracy and reliability of rotational INS. Each rotary unit independently rotates to modulate the errors of two gyros and two accelerometers. Three units can provide double sets of measurements along all three axes of body frame to constitute a couple of INSs which make TRUSINS redundant. Experiments and simulations based on a prototype which is made up of six fiber-optic gyros with drift stability of 0.05° h −1 show that TRUSINS can achieve positioning accuracy of about 0.256 n mile h −1 , which is ten times better than that of a normal non-rotational INS with the same level inertial sensors. The theoretical analysis and the experimental results show that due to the advantage of the innovative structure, the designed fault detection and isolation (FDI) strategy can tolerate six sensor faults at most, and is proved to be effective and practical. Therefore, TRUSINS is particularly suitable and highly beneficial for the applications where high accuracy and high reliability is required. (paper)

  10. Controllability of Surface Water Networks

    Science.gov (United States)

    Riasi, M. Sadegh; Yeghiazarian, Lilit

    2017-12-01

    To sustainably manage water resources, we must understand how to control complex networked systems. In this paper, we study surface water networks from the perspective of structural controllability, a concept that integrates classical control theory with graph-theoretic formalism. We present structural controllability theory and compute four metrics: full and target controllability, control centrality and control profile (FTCP) that collectively determine the structural boundaries of the system's control space. We use these metrics to answer the following questions: How does the structure of a surface water network affect its controllability? How to efficiently control a preselected subset of the network? Which nodes have the highest control power? What types of topological structures dominate controllability? Finally, we demonstrate the structural controllability theory in the analysis of a wide range of surface water networks, such as tributary, deltaic, and braided river systems.

  11. Redundant unbalance compensation of an active magnetic bearing system

    Science.gov (United States)

    Hutterer, Markus; Kalteis, Gerald; Schrödl, Manfred

    2017-09-01

    To achieve a good running behavior of a magnetic levitated rotor, a well-developed position controller and different compensation methods are required. Two very important structures in this context are the reduction of the gyroscopic effect and the unbalance vibration. Both structures have in common that they need the angular velocity information for calculation. For industrial applications this information is normally provided by an angle sensor which is fixed on the rotor. The angle information is also necessary for the field oriented control of the electrical drive. The main drawback of external position sensors are the case of a breakdown or an error of the motor controller. Therefore, the magnetic bearing can get unstable, because no angular velocity information is provided. To overcome this problem the presented paper describes the development of a selfsensing unbalance rejection in combination with a selfsensing speed control of the motor controller. Selfsensing means in this context that no angle sensor is required for the unbalance or torque control. With such structures two redundant speed and angle information sources are available and can be used for the magnetic bearing and the motor controller without the usage of an angle sensor.

  12. Past and Present Biophysical Redundancy of Countries as a Buffer to Changes in Food Supply

    Science.gov (United States)

    Fader, Marianela; Rulli, Maria Cristina; Carr, Joel; Dell' Angelo, Jampel; D' Odorico, Paolo; Gephart, Jessica A.; Kummu, Matti; Magliocca, Nicholas; Porkka, Miina; Prell, Christina; hide

    2016-01-01

    Spatially diverse trends in population growth, climate change, industrialization, urbanization and economic development are expected to change future food supply and demand. These changes may affect the suitability of land for food production, implying elevated risks especially for resource constrained, food-importing countries. We present the evolution of biophysical redundancy for agricultural production at country level, from 1992 to 2012. Biophysical redundancy, defined as unused biotic and abiotic environmental resources, is represented by the potential food production of 'spare land', available water resources (i.e., not already used for human activities), as well as production increases through yield gap closure on cultivated areas and potential agricultural areas. In 2012, the biophysical redundancy of 75 (48) countries, mainly in North Africa, Western Europe, the Middle East and Asia, was insufficient to produce the caloric nutritional needs for at least 50% (25%) of their population during a year. Biophysical redundancy has decreased in the last two decades in 102 out of 155 countries, 11 of these went from high to limited redundancy, and nine of these from limited to very low redundancy. Although the variability of the drivers of change across different countries is high, improvements in yield and population growth have a clear impact on the decreases of redundancy towards the very low redundancy category. We took a more detailed look at countries classified as 'Low Income Economies (LIEs)' since they are particularly vulnerable to domestic or external food supply changes, due to their limited capacity to offset for food supply decreases with higher purchasing power on the international market. Currently, nine LIEs have limited or very low biophysical redundancy. Many of these showed a decrease in redundancy over the last two decades, which is not always linked with improvements in per capita food availability.

  13. Past and present biophysical redundancy of countries as a buffer to changes in food supply

    Science.gov (United States)

    Fader, Marianela; Rulli, Maria Cristina; Carr, Joel; Dell'Angelo, Jampel; D'Odorico, Paolo; Gephart, Jessica A.; Kummu, Matti; Magliocca, Nicholas; Porkka, Miina; Prell, Christina; Puma, Michael J.; Ratajczak, Zak; Seekell, David A.; Suweis, Samir; Tavoni, Alessandro

    2016-05-01

    Spatially diverse trends in population growth, climate change, industrialization, urbanization and economic development are expected to change future food supply and demand. These changes may affect the suitability of land for food production, implying elevated risks especially for resource-constrained, food-importing countries. We present the evolution of biophysical redundancy for agricultural production at country level, from 1992 to 2012. Biophysical redundancy, defined as unused biotic and abiotic environmental resources, is represented by the potential food production of ‘spare land’, available water resources (i.e., not already used for human activities), as well as production increases through yield gap closure on cultivated areas and potential agricultural areas. In 2012, the biophysical redundancy of 75 (48) countries, mainly in North Africa, Western Europe, the Middle East and Asia, was insufficient to produce the caloric nutritional needs for at least 50% (25%) of their population during a year. Biophysical redundancy has decreased in the last two decades in 102 out of 155 countries, 11 of these went from high to limited redundancy, and nine of these from limited to very low redundancy. Although the variability of the drivers of change across different countries is high, improvements in yield and population growth have a clear impact on the decreases of redundancy towards the very low redundancy category. We took a more detailed look at countries classified as ‘Low Income Economies (LIEs)’ since they are particularly vulnerable to domestic or external food supply changes, due to their limited capacity to offset for food supply decreases with higher purchasing power on the international market. Currently, nine LIEs have limited or very low biophysical redundancy. Many of these showed a decrease in redundancy over the last two decades, which is not always linked with improvements in per capita food availability.

  14. Distributed redundancy and robustness in complex systems

    KAUST Repository

    Randles, Martin

    2011-03-01

    The uptake and increasing prevalence of Web 2.0 applications, promoting new large-scale and complex systems such as Cloud computing and the emerging Internet of Services/Things, requires tools and techniques to analyse and model methods to ensure the robustness of these new systems. This paper reports on assessing and improving complex system resilience using distributed redundancy, termed degeneracy in biological systems, to endow large-scale complicated computer systems with the same robustness that emerges in complex biological and natural systems. However, in order to promote an evolutionary approach, through emergent self-organisation, it is necessary to specify the systems in an \\'open-ended\\' manner where not all states of the system are prescribed at design-time. In particular an observer system is used to select robust topologies, within system components, based on a measurement of the first non-zero Eigen value in the Laplacian spectrum of the components\\' network graphs; also known as the algebraic connectivity. It is shown, through experimentation on a simulation, that increasing the average algebraic connectivity across the components, in a network, leads to an increase in the variety of individual components termed distributed redundancy; the capacity for structurally distinct components to perform an identical function in a particular context. The results are applied to a specific application where active clustering of like services is used to aid load balancing in a highly distributed network. Using the described procedure is shown to improve performance and distribute redundancy. © 2010 Elsevier Inc.

  15. Multi-objective reliability optimization of series-parallel systems with a choice of redundancy strategies

    International Nuclear Information System (INIS)

    Safari, Jalal

    2012-01-01

    This paper proposes a variant of the Non-dominated Sorting Genetic Algorithm (NSGA-II) to solve a novel mathematical model for multi-objective redundancy allocation problems (MORAP). Most researchers about redundancy allocation problem (RAP) have focused on single objective optimization, while there has been some limited research which addresses multi-objective optimization. Also all mathematical multi-objective models of general RAP assume that the type of redundancy strategy for each subsystem is predetermined and known a priori. In general, active redundancy has traditionally received greater attention; however, in practice both active and cold-standby redundancies may be used within a particular system design. The choice of redundancy strategy then becomes an additional decision variable. Thus, the proposed model and solution method are to select the best redundancy strategy, type of components, and levels of redundancy for each subsystem that maximizes the system reliability and minimize total system cost under system-level constraints. This problem belongs to the NP-hard class. This paper presents a second-generation Multiple-Objective Evolutionary Algorithm (MOEA), named NSGA-II to find the best solution for the given problem. The proposed algorithm demonstrates the ability to identify a set of optimal solutions (Pareto front), which provides the Decision Maker (DM) with a complete picture of the optimal solution space. After finding the Pareto front, a procedure is used to select the best solution from the Pareto front. Finally, the advantages of the presented multi-objective model and of the proposed algorithm are illustrated by solving test problems taken from the literature and the robustness of the proposed NSGA-II is discussed.

  16. Functional redundancy patterns reveal non-random assembly rules in a species-rich marine assemblage.

    Directory of Open Access Journals (Sweden)

    Nicolas Guillemot

    Full Text Available The relationship between species and the functional diversity of assemblages is fundamental in ecology because it contains key information on functional redundancy, and functionally redundant ecosystems are thought to be more resilient, resistant and stable. However, this relationship is poorly understood and undocumented for species-rich coastal marine ecosystems. Here, we used underwater visual censuses to examine the patterns of functional redundancy for one of the most diverse vertebrate assemblages, the coral reef fishes of New Caledonia, South Pacific. First, we found that the relationship between functional and species diversity displayed a non-asymptotic power-shaped curve, implying that rare functions and species mainly occur in highly diverse assemblages. Second, we showed that the distribution of species amongst possible functions was significantly different from a random distribution up to a threshold of ∼90 species/transect. Redundancy patterns for each function further revealed that some functions displayed fast rates of increase in redundancy at low species diversity, whereas others were only becoming redundant past a certain threshold. This suggested non-random assembly rules and the existence of some primordial functions that would need to be fulfilled in priority so that coral reef fish assemblages can gain a basic ecological structure. Last, we found little effect of habitat on the shape of the functional-species diversity relationship and on the redundancy of functions, although habitat is known to largely determine assemblage characteristics such as species composition, biomass, and abundance. Our study shows that low functional redundancy is characteristic of this highly diverse fish assemblage, and, therefore, that even species-rich ecosystems such as coral reefs may be vulnerable to the removal of a few keystone species.

  17. An efficient particle swarm approach for mixed-integer programming in reliability-redundancy optimization applications

    International Nuclear Information System (INIS)

    Santos Coelho, Leandro dos

    2009-01-01

    The reliability-redundancy optimization problems can involve the selection of components with multiple choices and redundancy levels that produce maximum benefits, and are subject to the cost, weight, and volume constraints. Many classical mathematical methods have failed in handling nonconvexities and nonsmoothness in reliability-redundancy optimization problems. As an alternative to the classical optimization approaches, the meta-heuristics have been given much attention by many researchers due to their ability to find an almost global optimal solutions. One of these meta-heuristics is the particle swarm optimization (PSO). PSO is a population-based heuristic optimization technique inspired by social behavior of bird flocking and fish schooling. This paper presents an efficient PSO algorithm based on Gaussian distribution and chaotic sequence (PSO-GC) to solve the reliability-redundancy optimization problems. In this context, two examples in reliability-redundancy design problems are evaluated. Simulation results demonstrate that the proposed PSO-GC is a promising optimization technique. PSO-GC performs well for the two examples of mixed-integer programming in reliability-redundancy applications considered in this paper. The solutions obtained by the PSO-GC are better than the previously best-known solutions available in the recent literature

  18. An efficient particle swarm approach for mixed-integer programming in reliability-redundancy optimization applications

    Energy Technology Data Exchange (ETDEWEB)

    Santos Coelho, Leandro dos [Industrial and Systems Engineering Graduate Program, LAS/PPGEPS, Pontifical Catholic University of Parana, PUCPR, Imaculada Conceicao, 1155, 80215-901 Curitiba, Parana (Brazil)], E-mail: leandro.coelho@pucpr.br

    2009-04-15

    The reliability-redundancy optimization problems can involve the selection of components with multiple choices and redundancy levels that produce maximum benefits, and are subject to the cost, weight, and volume constraints. Many classical mathematical methods have failed in handling nonconvexities and nonsmoothness in reliability-redundancy optimization problems. As an alternative to the classical optimization approaches, the meta-heuristics have been given much attention by many researchers due to their ability to find an almost global optimal solutions. One of these meta-heuristics is the particle swarm optimization (PSO). PSO is a population-based heuristic optimization technique inspired by social behavior of bird flocking and fish schooling. This paper presents an efficient PSO algorithm based on Gaussian distribution and chaotic sequence (PSO-GC) to solve the reliability-redundancy optimization problems. In this context, two examples in reliability-redundancy design problems are evaluated. Simulation results demonstrate that the proposed PSO-GC is a promising optimization technique. PSO-GC performs well for the two examples of mixed-integer programming in reliability-redundancy applications considered in this paper. The solutions obtained by the PSO-GC are better than the previously best-known solutions available in the recent literature.

  19. Superlinearly scalable noise robustness of redundant coupled dynamical systems.

    Science.gov (United States)

    Kohar, Vivek; Kia, Behnam; Lindner, John F; Ditto, William L

    2016-03-01

    We illustrate through theory and numerical simulations that redundant coupled dynamical systems can be extremely robust against local noise in comparison to uncoupled dynamical systems evolving in the same noisy environment. Previous studies have shown that the noise robustness of redundant coupled dynamical systems is linearly scalable and deviations due to noise can be minimized by increasing the number of coupled units. Here, we demonstrate that the noise robustness can actually be scaled superlinearly if some conditions are met and very high noise robustness can be realized with very few coupled units. We discuss these conditions and show that this superlinear scalability depends on the nonlinearity of the individual dynamical units. The phenomenon is demonstrated in discrete as well as continuous dynamical systems. This superlinear scalability not only provides us an opportunity to exploit the nonlinearity of physical systems without being bogged down by noise but may also help us in understanding the functional role of coupled redundancy found in many biological systems. Moreover, engineers can exploit superlinear noise suppression by starting a coupled system near (not necessarily at) the appropriate initial condition.

  20. Structural data collection with mobile devices: Accuracy, redundancy, and best practices

    Science.gov (United States)

    Allmendinger, Richard W.; Siron, Christopher R.; Scott, Chelsea P.

    2017-09-01

    Smart phones are equipped with numerous sensors that enable orientation data collection for structural geology at a rate up to an order of magnitude faster than traditional analog compasses. The rapidity of measurement enables field structural geologists, for the first time, to enjoy the benefits of data redundancy and quantitative uncertainty estimates. Recent work, however, has called into question the reliability of sensors on Android devices. We present here our experience with programming a new smart phone app from scratch, and using it and commercial apps on iOS devices along with analog compasses in a series of controlled tests and typical field use cases. Additionally, we document the relationships between iPhone measurements and visible structures in satellite, drawing on a database of 3700 iPhone measurements of coseismic surface cracks we made in northern Chile following the Mw8.1 Pisagua earthquake in 2014. By comparing phone-collected attitudes to orientations determined independently of the magnetic field, we avoid having to assume that the analog compass, which is subject to its own uncertainties, is the canonical instrument. Our results suggest that iOS devices are suitable for all but the most demanding applications as long as particular care is taken with respect to metal and electronic objects that could affect the magnetic field.

  1. Constrained control allocation for systems with redundant control effectors

    OpenAIRE

    Bordignon, Kenneth A

    1996-01-01

    Control allocation is examined for linear time-invariant problems that have more controls than degrees of freedom. The controls are part of a physical system and are subject to limits on their maximum positions. A control allocation scheme commands control deflections in response to some desired output. The ability of a control allocation scheme to produce the desired output without violating the physical position constraints is used to compare allocation schemes. Methods are develop...

  2. Mutual information and redundancy in spontaneous communication between cortical neurons.

    Science.gov (United States)

    Szczepanski, J; Arnold, M; Wajnryb, E; Amigó, J M; Sanchez-Vives, M V

    2011-03-01

    An important question in neural information processing is how neurons cooperate to transmit information. To study this question, we resort to the concept of redundancy in the information transmitted by a group of neurons and, at the same time, we introduce a novel concept for measuring cooperation between pairs of neurons called relative mutual information (RMI). Specifically, we studied these two parameters for spike trains generated by neighboring neurons from the primary visual cortex in the awake, freely moving rat. The spike trains studied here were spontaneously generated in the cortical network, in the absence of visual stimulation. Under these conditions, our analysis revealed that while the value of RMI oscillated slightly around an average value, the redundancy exhibited a behavior characterized by a higher variability. We conjecture that this combination of approximately constant RMI and greater variable redundancy makes information transmission more resistant to noise disturbances. Furthermore, the redundancy values suggest that neurons can cooperate in a flexible way during information transmission. This mostly occurs via a leading neuron with higher transmission rate or, less frequently, through the information rate of the whole group being higher than the sum of the individual information rates-in other words in a synergetic manner. The proposed method applies not only to the stationary, but also to locally stationary neural signals.

  3. Multisensory processing of redundant information in go/no-go and choice responses

    DEFF Research Database (Denmark)

    Blurton, Steven Paul; Greenlee, Mark W.; Gondan, Matthias

    2014-01-01

    In multisensory research, faster responses are commonly observed when multimodal stimuli are presented as compared to unimodal target presentations. This so-called redundant signals effect can be explained by several frameworks including separate activation and coactivation models. The redundant ...... of redundant information provided by different sensory channels and is not restricted to simple responses. The results connect existing theories on multisensory integration with theories on choice behavior....... processes (Schwarz, 1994) within two absorbing barriers. The diffusion superposition model accurately describes mean and variance of response times as well as the proportion of correct responses observed in the two tasks. Linear superposition seems, thus, to be a general principle in integration...

  4. Synergy and redundancy in the Granger causal analysis of dynamical networks

    International Nuclear Information System (INIS)

    Stramaglia, Sebastiano; M Cortes, Jesus; Marinazzo, Daniele

    2014-01-01

    We analyze, by means of Granger causality (GC), the effect of synergy and redundancy in the inference (from time series data) of the information flow between subsystems of a complex network. While we show that fully conditioned GC (CGC) is not affected by synergy, the pairwise analysis fails to prove synergetic effects. In cases when the number of samples is low, thus making the fully conditioned approach unfeasible, we show that partially conditioned GC (PCGC) is an effective approach if the set of conditioning variables is properly chosen. Here we consider two different strategies (based either on informational content for the candidate driver or on selecting the variables with highest pairwise influences) for PCGC and show that, depending on the data structure, either one or the other might be equally valid. On the other hand, we observe that fully conditioned approaches do not work well in the presence of redundancy, thus suggesting the strategy of separating the pairwise links in two subsets: those corresponding to indirect connections of the CGC (which should thus be excluded) and links that can be ascribed to redundancy effects and, together with the results from the fully connected approach, provide a better description of the causality pattern in the presence of redundancy. Finally we apply these methods to two different real datasets. First, analyzing electrophysiological data from an epileptic brain, we show that synergetic effects are dominant just before seizure occurrences. Second, our analysis applied to gene expression time series from HeLa culture shows that the underlying regulatory networks are characterized by both redundancy and synergy. (paper)

  5. Modal space three-state feedback control for electro-hydraulic servo plane redundant driving mechanism with eccentric load decoupling.

    Science.gov (United States)

    Zhao, Jinsong; Wang, Zhipeng; Zhang, Chuanbi; Yang, Chifu; Bai, Wenjie; Zhao, Zining

    2018-06-01

    The shaking table based on electro-hydraulic servo parallel mechanism has the advantage of strong carrying capacity. However, the strong coupling caused by the eccentric load not only affects the degree of freedom space control precision, but also brings trouble to the system control. A novel decoupling control strategy is proposed, which is based on modal space to solve the coupling problem for parallel mechanism with eccentric load. The phenomenon of strong dynamic coupling among degree of freedom space is described by experiments, and its influence on control design is discussed. Considering the particularity of plane motion, the dynamic model is built by Lagrangian method to avoid complex calculations. The dynamic equations of the coupling physical space are transformed into the dynamic equations of the decoupling modal space by using the weighted orthogonality of the modal main mode with respect to mass matrix and stiffness matrix. In the modal space, the adjustments of the modal channels are independent of each other. Moreover, the paper discusses identical closed-loop dynamic characteristics of modal channels, which will realize decoupling for degree of freedom space, thus a modal space three-state feedback control is proposed to expand the frequency bandwidth of each modal channel for ensuring their near-identical responses in a larger frequency range. Experimental results show that the concept of modal space three-state feedback control proposed in this paper can effectively reduce the strong coupling problem of degree of freedom space channels, which verify the effectiveness of the proposed model space state feedback control strategy for improving the control performance of the electro-hydraulic servo plane redundant driving mechanism. Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.

  6. Redundancy of einselected information in quantum Darwinism: The irrelevance of irrelevant environment bits

    Science.gov (United States)

    Zwolak, Michael; Zurek, Wojciech H.

    2017-03-01

    The objective, classical world emerges from the underlying quantum substrate via the proliferation of redundant copies of selected information into the environment, which acts as a communication channel, transmitting that information to observers. These copies are independently accessible, allowing many observers to reach consensus about the state of a quantum system via its imprints in the environment. Quantum Darwinism recognizes that the redundancy of information is thus central to the emergence of objective reality in the quantum world. However, in addition to the "quantum system of interest," there are many other systems "of no interest" in the Universe that can imprint information on the common environment. There is therefore a danger that the information of interest will be diluted with irrelevant bits, suppressing the redundancy responsible for objectivity. We show that mixing of the relevant (the "wheat") and irrelevant (the "chaff") bits of information makes little quantitative difference to the redundancy of the information of interest. Thus, we demonstrate that it does not matter whether one separates the wheat (relevant information) from the (irrelevant) chaff: The large redundancy of the relevant information survives dilution, providing evidence of the objective, effectively classical world.

  7. Design method of redundancy of brace-anchor sharing supporting based on cooperative deformation

    Science.gov (United States)

    Liu, Jun-yan; Li, Bing; Liu, Yan; Cai, Shan-bing

    2017-11-01

    Because of the complicated environment requirement, the support form of foundation pit is diversified, and the brace-anchor sharing support is widely used. However, the research on the force deformation characteristics and the related aspects of the cooperative response of the brace-anchor sharing support is insufficient. The application of redundancy theory in structural engineering has been more mature, but there is little theoretical research on redundancy theory in underground engineering. Based on the idea of collaborative deformation, the paper calculates the ratio of the redundancy degree of the cooperative deformation by using the local reinforcement design method and the structural component redundancy parameter calculation formula based on Frangopol. Combined with the engineering case, through the calculation of the ratio of cooperative deformation redundancy in the joint of brace-anchor sharing support. This paper explores the optimal anchor distribution form under the condition of cooperative deformation, and through the analysis and research of displacement field and stress field, the results of the collaborative deformation are validated by comparing the field monitoring data. It provides theoretical basis for the design of this kind of foundation pit in the future.

  8. The impact of the operating environment on the design of redundant configurations

    International Nuclear Information System (INIS)

    Marseguerra, M.; Padovani, E.; Zio, E.

    1999-01-01

    Safety systems are often characterized by substantial redundancy and diversification in safety critical components. In principle, such redundancy and diversification can bring benefits when compared to single-component systems. However, it has also been recognized that the evaluation of these benefits should take into account that redundancies cannot be founded, in practice, on the assumption of complete independence, so that the resulting risk profile is strongly dominated by dependent failures. It is therefore mandatory that the effects of common cause failures be estimated in any probabilistic safety assessment (PSA). Recently, in the Hughes model for hardware failures and in the Eckhardt and Lee models for software failures, it was proposed that the stressfulness of the operating environment affects the probability that a particular type of component will fail. Thus, dependence of component failure behaviors can arise indirectly through the variability of the environment which can directly affect the success of a redundant configuration. In this paper we investigate the impact of indirect component dependence by means of the introduction of a probability distribution which describes the variability of the environment. We show that the variance of the distribution of the number, or times, of system failures can give an indication of the presence of the environment. Further, the impact of the environment is shown to affect the reliability and the design of redundant configurations

  9. Does plant species richness guarantee the resilience of local medical systems? A perspective from utilitarian redundancy.

    Directory of Open Access Journals (Sweden)

    Flávia Rosa Santoro

    Full Text Available Resilience is related to the ability of a system to adjust to disturbances. The Utilitarian Redundancy Model has emerged as a tool for investigating the resilience of local medical systems. The model determines the use of species richness for the same therapeutic function as a facilitator of the maintenance of these systems. However, predictions generated from this model have not yet been tested, and a lack of variables exists for deeper analyses of resilience. This study aims to address gaps in the Utilitarian Redundancy Model and to investigate the resilience of two medical systems in the Brazilian semi-arid zone. As a local illness is not always perceived in the same way that biomedicine recognizes, the term "therapeutic targets" is used for perceived illnesses. Semi-structured interviews with local experts were conducted using the free-listing technique to collect data on known medicinal plants, usage preferences, use of redundant species, characteristics of therapeutic targets, and the perceived severity for each target. Additionally, participatory workshops were conducted to determine the frequency of targets. The medical systems showed high species richness but low levels of species redundancy. However, if redundancy was present, it was the primary factor responsible for the maintenance of system functions. Species richness was positively associated with therapeutic target frequencies and negatively related to target severity. Moreover, information about redundant species seems to be largely idiosyncratic; this finding raises questions about the importance of redundancy for resilience. We stress the Utilitarian Redundancy Model as an interesting tool to be used in studies of resilience, but we emphasize that it must consider the distribution of redundancy in terms of the treatment of important illnesses and the sharing of information. This study has identified aspects of the higher and lower vulnerabilities of medical systems, adding

  10. Redundant arrays of IDE drives

    Energy Technology Data Exchange (ETDEWEB)

    D.A. Sanders et al.

    2002-01-02

    The authors report tests of redundant arrays of IDE disk drives for use in offline high energy physics data analysis. Parts costs of total systems using commodity EIDE disks are now at the $4000 per Terabyte level. Disk storage prices have now decreased to the point where they equal the cost per Terabyte of Storage Technology tape silos. The disks, however, offer far better granularity; even small institutions can afford to deploy systems. The tests include reports on software RAID-5 systems running under Linux 2.4 using Promise Ultra 100{trademark} disk controllers. RAID-5 protects data in case of a single disk failure by providing parity bits. Tape backup is not required. Journaling file systems are used to allow rapid recovery from crashes. The data analysis strategy is to encapsulate data and CPU processing power. Analysis for a particular part of a data set takes place on the PC where the data resides. The network is only used to put results together. They explore three methods of moving data between sites; internet transfers, not pluggable IDE disks in FireWire cases, and DVD-R disks.

  11. Redundant arrays of IDE drives

    International Nuclear Information System (INIS)

    Sanders, D.A.

    2002-01-01

    The authors report tests of redundant arrays of IDE disk drives for use in offline high energy physics data analysis. Parts costs of total systems using commodity EIDE disks are now at the $4000 per Terabyte level. Disk storage prices have now decreased to the point where they equal the cost per Terabyte of Storage Technology tape silos. The disks, however, offer far better granularity; even small institutions can afford to deploy systems. The tests include reports on software RAID-5 systems running under Linux 2.4 using Promise Ultra 100trademark disk controllers. RAID-5 protects data in case of a single disk failure by providing parity bits. Tape backup is not required. Journaling file systems are used to allow rapid recovery from crashes. The data analysis strategy is to encapsulate data and CPU processing power. Analysis for a particular part of a data set takes place on the PC where the data resides. The network is only used to put results together. They explore three methods of moving data between sites; internet transfers, not pluggable IDE disks in FireWire cases, and DVD-R disks

  12. Integrated Application of Active Controls (IAAC) technology to an advanced subsonic transport project: Current and advanced act control system definition study, volume 1

    Science.gov (United States)

    Hanks, G. W.; Shomber, H. A.; Dethman, H. A.; Gratzer, L. B.; Maeshiro, A.; Gangsaas, D.; Blight, J. D.; Buchan, S. M.; Crumb, C. B.; Dorwart, R. J.

    1981-01-01

    An active controls technology (ACT) system architecture was selected based on current technology system elements and optimal control theory was evaluated for use in analyzing and synthesizing ACT multiple control laws. The system selected employs three redundant computers to implement all of the ACT functions, four redundant smaller computers to implement the crucial pitch-augmented stability function, and a separate maintenance and display computer. The reliability objective of probability of crucial function failure of less than 1 x 10 to the -9th power per flight of 1 hr can be met with current technology system components, if the software is assumed fault free and coverage approaching 1.0 can be provided. The optimal control theory approach to ACT control law synthesis yielded comparable control law performance much more systematically and directly than the classical s-domain approach. The ACT control law performance, although somewhat degraded by the inclusion of representative nonlinearities, remained quite effective. Certain high-frequency gust-load alleviation functions may require increased surface rate capability.

  13. Fuzzy modeling of analytical redundancy for sensor failure detection

    International Nuclear Information System (INIS)

    Tsai, T.M.; Chou, H.P.

    1991-01-01

    Failure detection and isolation (FDI) in dynamic systems may be accomplished by testing the consistency of the system via analytically redundant relations. The redundant relation is basically a mathematical model relating system inputs and dissimilar sensor outputs from which information is extracted and subsequently examined for the presence of failure signatures. Performance of the approach is often jeopardized by inherent modeling error and noise interference. To mitigate such effects, techniques such as Kalman filtering, auto-regression-moving-average (ARMA) modeling in conjunction with probability tests are often employed. These conventional techniques treat the stochastic nature of uncertainties in a deterministic manner to generate best-estimated model and sensor outputs by minimizing uncertainties. In this paper, the authors present a different approach by treating the effect of uncertainties with fuzzy numbers. Coefficients in redundant relations derived from first-principle physical models are considered as fuzzy parameters and on-line updated according to system behaviors. Failure detection is accomplished by examining the possibility that a sensor signal occurred in an estimated fuzzy domain. To facilitate failure isolation, individual FDI monitors are designed for each interested sensor

  14. Information filtering based on corrected redundancy-eliminating mass diffusion.

    Science.gov (United States)

    Zhu, Xuzhen; Yang, Yujie; Chen, Guilin; Medo, Matus; Tian, Hui; Cai, Shi-Min

    2017-01-01

    Methods used in information filtering and recommendation often rely on quantifying the similarity between objects or users. The used similarity metrics often suffer from similarity redundancies arising from correlations between objects' attributes. Based on an unweighted undirected object-user bipartite network, we propose a Corrected Redundancy-Eliminating similarity index (CRE) which is based on a spreading process on the network. Extensive experiments on three benchmark data sets-Movilens, Netflix and Amazon-show that when used in recommendation, the CRE yields significant improvements in terms of recommendation accuracy and diversity. A detailed analysis is presented to unveil the origins of the observed differences between the CRE and mainstream similarity indices.

  15. Low-redundancy linear arrays in mirrored interferometric aperture synthesis.

    Science.gov (United States)

    Zhu, Dong; Hu, Fei; Wu, Liang; Li, Jun; Lang, Liang

    2016-01-15

    Mirrored interferometric aperture synthesis (MIAS) is a novel interferometry that can improve spatial resolution compared with that of conventional IAS. In one-dimensional (1-D) MIAS, antenna array with low redundancy has the potential to achieve a high spatial resolution. This Letter presents a technique for the direct construction of low-redundancy linear arrays (LRLAs) in MIAS and derives two regular analytical patterns that can yield various LRLAs in short computation time. Moreover, for a better estimation of the observed scene, a bi-measurement method is proposed to handle the rank defect associated with the transmatrix of those LRLAs. The results of imaging simulation demonstrate the effectiveness of the proposed method.

  16. Structural redundance of NPPs and diagnostics

    International Nuclear Information System (INIS)

    Znyshev, V.V.; Sabaev, E.F.

    1988-01-01

    A new approach to functional diagnosis of NPP state based on structural redundance, owing to which in major of the facilities there are elements identical as to the structure and operational conditions, is suggested. The difference from zero by the given value for one parameter measured for various identical elements is an indicator of a failed element and a signal for diagnostic analysis

  17. Analysis of singularity in redundant manipulators

    International Nuclear Information System (INIS)

    Watanabe, Koichi

    2000-03-01

    In the analysis of arm positions and configurations of redundant manipulators, the singularity avoidance problems are important themes. This report presents singularity avoidance computations of a 7 DOF manipulator by using a computer code based on human-arm models. The behavior of the arm escaping from the singular point can be identified satisfactorily through the use of 3-D plotting tools. (author)

  18. One Size Does Not Fit All: Older Adults Benefit From Redundant Text in Multimedia Instruction

    Directory of Open Access Journals (Sweden)

    Barbara eFenesi

    2015-07-01

    Full Text Available The multimedia design of presentations typically ignores that younger and older adults have varying cognitive strengths and weaknesses. We examined whether differential instructional design may enhance learning in these populations. Younger and older participants viewed one of three computer-based presentations: Audio only (narration, Redundant (audio narration with redundant text, or Complementary (audio narration with non–redundant text and images. Younger participants learned better when audio narration was paired with relevant images compared to when audio narration was paired with redundant text. However, older participants learned best when audio narration was paired with redundant text. Younger adults, who presumably have a higher working memory capacity, appear to benefit more from complementary information that may drive deeper conceptual processing. In contrast, older adults learn better from presentations that support redundant coding across modalities, which may help mitigate the effects of age-related decline in working memory capacity. Additionally, several misconceptions of design quality appeared across age groups: both younger and older participants positively rated less effective designs. Findings suggest that one-size does not fit all, with older adults requiring unique multimedia design tailored to their cognitive abilities for effective learning.

  19. One size does not fit all: older adults benefit from redundant text in multimedia instruction.

    Science.gov (United States)

    Fenesi, Barbara; Vandermorris, Susan; Kim, Joseph A; Shore, David I; Heisz, Jennifer J

    2015-01-01

    The multimedia design of presentations typically ignores that younger and older adults have varying cognitive strengths and weaknesses. We examined whether differential instructional design may enhance learning in these populations. Younger and older participants viewed one of three computer-based presentations: Audio only (narration), Redundant (audio narration with redundant text), or Complementary (audio narration with non-redundant text and images). Younger participants learned better when audio narration was paired with relevant images compared to when audio narration was paired with redundant text. However, older participants learned best when audio narration was paired with redundant text. Younger adults, who presumably have a higher working memory capacity (WMC), appear to benefit more from complementary information that may drive deeper conceptual processing. In contrast, older adults learn better from presentations that support redundant coding across modalities, which may help mitigate the effects of age-related decline in WMC. Additionally, several misconceptions of design quality appeared across age groups: both younger and older participants positively rated less effective designs. Findings suggest that one-size does not fit all, with older adults requiring unique multimedia design tailored to their cognitive abilities for effective learning.

  20. Application of model-based and knowledge-based measuring methods as analytical redundancy

    International Nuclear Information System (INIS)

    Hampel, R.; Kaestner, W.; Chaker, N.; Vandreier, B.

    1997-01-01

    The safe operation of nuclear power plants requires the application of modern and intelligent methods of signal processing for the normal operation as well as for the management of accident conditions. Such modern and intelligent methods are model-based and knowledge-based ones being founded on analytical knowledge (mathematical models) as well as experiences (fuzzy information). In addition to the existing hardware redundancies analytical redundancies will be established with the help of these modern methods. These analytical redundancies support the operating staff during the decision-making. The design of a hybrid model-based and knowledge-based measuring method will be demonstrated by the example of a fuzzy-supported observer. Within the fuzzy-supported observer a classical linear observer is connected with a fuzzy-supported adaptation of the model matrices of the observer model. This application is realized for the estimation of the non-measurable variables as steam content and mixture level within pressure vessels with water-steam mixture during accidental depressurizations. For this example the existing non-linearities will be classified and the verification of the model will be explained. The advantages of the hybrid method in comparison to the classical model-based measuring methods will be demonstrated by the results of estimation. The consideration of the parameters which have an important influence on the non-linearities requires the inclusion of high-dimensional structures of fuzzy logic within the model-based measuring methods. Therefore methods will be presented which allow the conversion of these high-dimensional structures to two-dimensional structures of fuzzy logic. As an efficient solution of this problem a method based on cascaded fuzzy controllers will be presented. (author). 2 refs, 12 figs, 5 tabs

  1. One size does not fit all: older adults benefit from redundant text in multimedia instruction

    OpenAIRE

    Fenesi, Barbara; Vandermorris, Susan; Kim, Joseph A.; Shore, David I.; Heisz, Jennifer J.

    2015-01-01

    The multimedia design of presentations typically ignores that younger and older adults have varying cognitive strengths and weaknesses. We examined whether differential instructional design may enhance learning in these populations. Younger and older participants viewed one of three computer-based presentations: Audio only (narration), Redundant (audio narration with redundant text), or Complementary (audio narration with non–redundant text and images). Younger participants learned better ...

  2. Solving the redundancy allocation problem with multiple strategy choices using a new simplified particle swarm optimization

    International Nuclear Information System (INIS)

    Kong, Xiangyong; Gao, Liqun; Ouyang, Haibin; Li, Steven

    2015-01-01

    In most research on redundancy allocation problem (RAP), the redundancy strategy for each subsystem is assumed to be predetermined and fixed. This paper focuses on a specific RAP with multiple strategy choices (RAP-MSC), in which both active redundancy and cold standby redundancy can be selected as an additional decision variable for individual subsystems. To do so, the component type, redundancy strategy and redundancy level for each subsystem should be chosen subject to the system constraints appropriately such that the system reliability is maximized. Meanwhile, imperfect switching for cold standby redundancy is considered and a k-Erlang distribution is introduced to model the time-to-failure component as well. Given the importance and complexity of RAP-MSC, we propose a new efficient simplified version of particle swarm optimization (SPSO) to solve such NP-hard problems. In this method, a new position updating scheme without velocity is presented with stochastic disturbance and a low probability. Moreover, it is compared with several well-known PSO variants and other state-of-the-art approaches in the literature to evaluate its performance. The experiment results demonstrate the superiority of SPSO as an alternative for solving the RAP-MSC. - Highlights: • A more realistic RAP form with multiple strategy choices is focused. • Redundancy strategies are to be selected rather than fixed in general RAP. • A new simplified particle swarm optimization is proposed. • Higher reliabilities are achieved than the state-of-the-art approaches.

  3. Fractional order modeling and control of dissimilar redundant actuating system used in large passenger aircraft

    Directory of Open Access Journals (Sweden)

    Salman IJAZ

    2018-05-01

    Full Text Available In this paper, a methodology has been developed to address the issue of force fighting and to achieve precise position tracking of control surface driven by two dissimilar actuators. The nonlinear dynamics of both actuators are first approximated as fractional order models. Based on the identified models, three fractional order controllers are proposed for the whole system. Two Fractional Order PID (FOPID controllers are dedicated to improving transient response and are designed in a position feedback configuration. In order to synchronize the actuator dynamics, a third fractional order PI controller is designed, which feeds the force compensation signal in position feedback loop of both actuators. Nelder-Mead (N-M optimization technique is employed in order to optimally tune controller parameters based on the proposed performance criteria. To test the proposed controllers according to real flight condition, an external disturbance of higher amplitude that acts as airload is applied directly on the control surface. In addition, a disturbance signal function of system states is applied to check the robustness of proposed controller. Simulation results on nonlinear system model validated the performance of the proposed scheme as compared to optimal PID and high gain PID controllers. Keywords: Aerospace, Fractional order control, Model identification, Nelder-Mead optimization, Robustness

  4. Dynamically redundant particle components in mixtures

    International Nuclear Information System (INIS)

    Lukacs, B.; Martinas, K.

    1984-10-01

    Examples are shown for cases in which the number of different kinds of particles in a system is not necessarily equal to the number of particle degrees of freedom in thermodynamical sense, and at the same time, the observed dynamics of the evolution of the system does not indicate a definite number of degrees of freedeom. The possibility for introducing dynamically redundant particles is discussed. (author)

  5. A Redundancy Mechanism Design for Hall-Based Electronic Current Transformers

    Directory of Open Access Journals (Sweden)

    Kun-Long Chen

    2017-03-01

    Full Text Available Traditional current transformers (CTs suffer from DC and AC saturation and remanent magnetization in many industrial applications. Moreover, the drawbacks of traditional CTs, such as closed iron cores, bulky volume, and heavy weight, further limit the development of an intelligent power protection system. In order to compensate for these drawbacks, we proposed a novel current measurement method by using Hall sensors, which is called the Hall-effect current transformer (HCT. The existing commercial Hall sensors are electronic components, so the reliability of the HCT is normally worse than that of the traditional CT. Therefore, our study proposes a redundancy mechanism for the HCT to strengthen its reliability. With multiple sensor modules, the method has the ability to improve the accuracy of the HCT as well. Additionally, the proposed redundancy mechanism monitoring system provides a condition-based maintenance for the HCT. We verify our method with both simulations and an experimental test. The results demonstrate that the proposed HCT with a redundancy mechanism can almost achieve Class 0.2 for measuring CTs according to IEC Standard 60044-8.

  6. Susceptibility of Redundant Versus Singular Clock Domains Implemented in SRAM-Based FPGA TMR Designs

    Science.gov (United States)

    Berg, Melanie D.; LaBel, Kenneth A.; Pellish, Jonathan

    2016-01-01

    We present the challenges that arise when using redundant clock domains due to their clock-skew. Radiation data show that a singular clock domain (DTMR) provides an improved TMR methodology for SRAM-based FPGAs over redundant clocks.

  7. Information filtering based on corrected redundancy-eliminating mass diffusion.

    Directory of Open Access Journals (Sweden)

    Xuzhen Zhu

    Full Text Available Methods used in information filtering and recommendation often rely on quantifying the similarity between objects or users. The used similarity metrics often suffer from similarity redundancies arising from correlations between objects' attributes. Based on an unweighted undirected object-user bipartite network, we propose a Corrected Redundancy-Eliminating similarity index (CRE which is based on a spreading process on the network. Extensive experiments on three benchmark data sets-Movilens, Netflix and Amazon-show that when used in recommendation, the CRE yields significant improvements in terms of recommendation accuracy and diversity. A detailed analysis is presented to unveil the origins of the observed differences between the CRE and mainstream similarity indices.

  8. A Cause-Consequence Chart of a Redundant Protection System

    DEFF Research Database (Denmark)

    Nielsen, Dan Sandvik; Platz, O.; Runge, B.

    1975-01-01

    A cause-consequence chart is applied in analysing failures of a redundant protection system (a core spray system in a nuclear power plant). It is shown how the diagram provides a basis for calculating two probability measures for malfunctioning of the protection system. The test policy of compone...... of components is taken into account. The possibility of using parameter variation as a basis for the choice of test policy is indicated.......A cause-consequence chart is applied in analysing failures of a redundant protection system (a core spray system in a nuclear power plant). It is shown how the diagram provides a basis for calculating two probability measures for malfunctioning of the protection system. The test policy...

  9. Flat H Redundant Frangible Joint Development

    Science.gov (United States)

    Brown, Chris

    2016-01-01

    Orion and Commercial Crew Program (CCP) Partners have chosen to use frangible joints for certain separation events. The joints currently available are zero failure tolerant and will be used in mission safety applications. The goal is to further develop a NASA designed redundant frangible joint that will lower flight risk and increase reliability. FY16 testing revealed a successful design in subscale straight test specimens that gained efficiency and supports Orion load requirements. Approach / Innovation A design constraint is that the redundant joint must fit within the current Orion architecture, without the need for additional vehicle modification. This limitation required a design that changed the orientation of the expanding tube assemblies (XTAs), by rotating them 90deg from the standard joint configuration. The change is not trivial and affects the fracture mechanism and structural load paths. To address these changes, the design incorporates cantilevered arms on the break plate. The shock transmission and expansion of the XTA applies force to these arms and creates a prying motion to push the plate walls outward to the point of structural failure at the notched section. The 2014 test design revealed that parts could slip during functioning wasting valuable energy needed to separate the structure with only a single XTA functioning. Dual XTA functioning fully separated the assembly showing a discrepancy can be backed up with redundancy. Work on other fully redundant systems outside NASA is limited to a few patents that have not been subjected to functionality testing Design changes to prevent unwanted slippage (with ICA funding in 2015) showed success with a single XTA. The main goal for FY 2016 was to send the new Flat H RFJ to WSTF where single XTA test failures occurred back in 2014. The plan was to gain efficiency in this design by separating the Flat H RFJ with thicker ligaments with dimensions baselined in 2014. Other modifications included geometry

  10. Biogeographical disparity in the functional diversity and redundancy of corals.

    Science.gov (United States)

    McWilliam, Mike; Hoogenboom, Mia O; Baird, Andrew H; Kuo, Chao-Yang; Madin, Joshua S; Hughes, Terry P

    2018-03-20

    Corals are major contributors to a range of key ecosystem functions on tropical reefs, including calcification, photosynthesis, nutrient cycling, and the provision of habitat structure. The abundance of corals is declining at multiple scales, and the species composition of assemblages is responding to escalating human pressures, including anthropogenic global warming. An urgent challenge is to understand the functional consequences of these shifts in abundance and composition in different biogeographical contexts. While global patterns of coral species richness are well known, the biogeography of coral functions in provinces and domains with high and low redundancy is poorly understood. Here, we quantify the functional traits of all currently recognized zooxanthellate coral species ( n = 821) in both the Indo-Pacific and Atlantic domains to examine the relationships between species richness and the diversity and redundancy of functional trait space. We find that trait diversity is remarkably conserved (>75% of the global total) along latitudinal and longitudinal gradients in species richness, falling away only in species-poor provinces ( n < 200), such as the Persian Gulf (52% of the global total), Hawaii (37%), the Caribbean (26%), and the East-Pacific (20%), where redundancy is also diminished. In the more species-poor provinces, large and ecologically important areas of trait space are empty, or occupied by just a few, highly distinctive species. These striking biogeographical differences in redundancy could affect the resilience of critical reef functions and highlight the vulnerability of relatively depauperate, peripheral locations, which are often a low priority for targeted conservation efforts.

  11. Analysis of informational redundancy in the protein-assembling machinery

    Science.gov (United States)

    Berkovich, Simon

    2004-03-01

    Entropy analysis of the DNA structure does not reveal a significant departure from randomness indicating lack of informational redundancy. This signifies the absence of a hidden meaning in the genome text and supports the 'barcode' interpretation of DNA given in [1]. Lack of informational redundancy is a characteristic property of an identification label rather than of a message of instructions. Yet randomness of DNA has to induce non-random structures of the proteins. Protein synthesis is a two-step process: transcription into RNA with gene splicing and formation a structure of amino acids. Entropy estimations, performed by A. Djebbari, show typical values of redundancy of the biomolecules along these pathways: DNA gene 4proteins 15-40in gene expression, the RNA copy carries the same information as the original DNA template. Randomness is essentially eliminated only at the step of the protein creation by a degenerate code. According to [1], the significance of the substitution of U for T with a subsequent gene splicing is that these transformations result in a different pattern of RNA oscillations, so the vital DNA communications are protected against extraneous noise coming from the protein making activities. 1. S. Berkovich, "On the 'barcode' functionality of DNA, or the Phenomenon of Life in the Physical Universe", Dorrance Publishing Co., Pittsburgh, 2003

  12. The Interface Between Redundant Processor Modules Of Safety Grade PLC Using Mass Storage DPRAM

    International Nuclear Information System (INIS)

    Hwang, Sung Jae; Song, Seong Hwan; No, Young Hun; Yun, Dong Hwa; Park, Gang Min; Kim, Min Gyu; Choi, Kyung Chul; Lee, Ui Taek

    2010-01-01

    Processor module of safety grade PLC (hereinafter called as POSAFE-Q) developed by POSCO ICT provides high reliability and safety. However, POSAFEQ would have suffered a malfunction when we think taking place of abnormal operation by exceptional environmental. POSAFE-Q would not able to conduct its function normally in such case. To prevent these situations, the necessity of redundant processor module has been raised. Therefore, redundant processor module, NCPU-2Q, has been developed which has not only functions of single processor module with high reliability and safety but also functions of redundant processor

  13. [Shang Ring circumcision versus conventional circumcision for redundant prepuce or phimosis: a meta analysis].

    Science.gov (United States)

    Xiao, Er-Long; Ding, Hui; Li, Yong-Qian; Wang, Zhi-Ping

    2013-10-01

    To compare the effect and safety of Shang Ring circumcision with those of conventional circumcision in the treatment of redundant prepuce or phimosis. We retrieved the randomized controlled trials on Shang Ring circumcision and conventional circumcision for the treatment of redundant prepuce or phimosis published at home and abroad. Relevant data were selected according to the Cochrane Handbook for Systematic Reviews by two reviewers after quality evaluation of the included trials, and the statistical software RevMan 5.0 was used for meta analysis. Totally 8 randomized controlled trials with 2277 cases were included in this study. Compared with conventional circumcision, Shang Ring circumcision showed a shorter operation time (SMD = -5.82, 95% CI [ -7.39, -4.24], PSMD = -3.28, 95% CI [ -3.47, -3.09], Pinfection (OR = 0.44, 95% CI [0.26, 0.72], P=0.001), lower rate of postoperative bleeding (OR =0.05, 95% CI [0.02, 0.12], PSMD = -3.32, 95% CI [ -3.50, -3.14], PSMD = -3.28, 95% CI [ - 3.47, - 3.00], P<0.00001), but longer wound healing time (OR=1.46, 95% CI [1.03, 1.90], P<0.00001). In comparison with conventional circumcision, Shang Ring circumcision has the advantages of shorter operation time, fewer complications, mild pain, and higher rate of satisfaction with the postoperative penile appearance. However, more high-quality randomized controlled trials with large samples are required to lend further support to our findings.

  14. Ageing behaviour of [(n-1)/n] active redundancy systems

    International Nuclear Information System (INIS)

    Eid, M.Y.

    1995-01-01

    Ageing of systems becomes a real concern if intelligent maintenance is required. Determining the ageing behaviour of a system necessitate having a powerful calculating tool and knowing the ageing behaviour of the basic components of the systems. Consequently, time dependent failure rates are required for basic components and need to be determined for systems. As, this is the general problem in reliability analysis, only (n-1)/n active redundancy system will be examined in the paper. Systems with (n-1)/n active redundancy are commonly used in a wide range of engineering fields. This should permit a priori improving the system reliability. Still, a deeper analysis of the ageing behaviour of such systems may reveal some particular aspects. (authors). 2 refs., 5 figs

  15. Comparing surgical trays with redundant instruments with trays with reduced instruments: a cost analysis.

    Science.gov (United States)

    John-Baptiste, A; Sowerby, L J; Chin, C J; Martin, J; Rotenberg, B W

    2016-01-01

    When prearranged standard surgical trays contain instruments that are repeatedly unused, the redundancy can result in unnecessary health care costs. Our objective was to estimate potential savings by performing an economic evaluation comparing the cost of surgical trays with redundant instruments with surgical trays with reduced instruments ("reduced trays"). We performed a cost-analysis from the hospital perspective over a 1-year period. Using a mathematical model, we compared the direct costs of trays containing redundant instruments to reduced trays for 5 otolaryngology procedures. We incorporated data from several sources including local hospital data on surgical volume, the number of instruments on redundant and reduced trays, wages of personnel and time required to pack instruments. From the literature, we incorporated instrument depreciation costs and the time required to decontaminate an instrument. We performed 1-way sensitivity analyses on all variables, including surgical volume. Costs were estimated in 2013 Canadian dollars. The cost of redundant trays was $21 806 and the cost of reduced trays was $8803, for a 1-year cost saving of $13 003. In sensitivity analyses, cost savings ranged from $3262 to $21 395, based on the surgical volume at the institution. Variation in surgical volume resulted in a wider range of estimates, with a minimum of $3253 for low-volume to a maximum of $52 012 for high-volume institutions. Our study suggests moderate savings may be achieved by reducing surgical tray redundancy and, if applied to other surgical specialties, may result in savings to Canadian health care systems.

  16. Pauci ex tanto numero: reduce redundancy in multi-model ensembles

    Science.gov (United States)

    Solazzo, E.; Riccio, A.; Kioutsioukis, I.; Galmarini, S.

    2013-08-01

    We explicitly address the fundamental issue of member diversity in multi-model ensembles. To date, no attempts in this direction have been documented within the air quality (AQ) community despite the extensive use of ensembles in this field. Common biases and redundancy are the two issues directly deriving from lack of independence, undermining the significance of a multi-model ensemble, and are the subject of this study. Shared, dependant biases among models do not cancel out but will instead determine a biased ensemble. Redundancy derives from having too large a portion of common variance among the members of the ensemble, producing overconfidence in the predictions and underestimation of the uncertainty. The two issues of common biases and redundancy are analysed in detail using the AQMEII ensemble of AQ model results for four air pollutants in two European regions. We show that models share large portions of bias and variance, extending well beyond those induced by common inputs. We make use of several techniques to further show that subsets of models can explain the same amount of variance as the full ensemble with the advantage of being poorly correlated. Selecting the members for generating skilful, non-redundant ensembles from such subsets proved, however, non-trivial. We propose and discuss various methods of member selection and rate the ensemble performance they produce. In most cases, the full ensemble is outscored by the reduced ones. We conclude that, although independence of outputs may not always guarantee enhancement of scores (but this depends upon the skill being investigated), we discourage selecting the members of the ensemble simply on the basis of scores; that is, independence and skills need to be considered disjointly.

  17. The Identity of Information: How Deterministic Dependencies Constrain Information Synergy and Redundancy

    Directory of Open Access Journals (Sweden)

    Daniel Chicharro

    2018-03-01

    Full Text Available Understanding how different information sources together transmit information is crucial in many domains. For example, understanding the neural code requires characterizing how different neurons contribute unique, redundant, or synergistic pieces of information about sensory or behavioral variables. Williams and Beer (2010 proposed a partial information decomposition (PID that separates the mutual information that a set of sources contains about a set of targets into nonnegative terms interpretable as these pieces. Quantifying redundancy requires assigning an identity to different information pieces, to assess when information is common across sources. Harder et al. (2013 proposed an identity axiom that imposes necessary conditions to quantify qualitatively common information. However, Bertschinger et al. (2012 showed that, in a counterexample with deterministic target-source dependencies, the identity axiom is incompatible with ensuring PID nonnegativity. Here, we study systematically the consequences of information identity criteria that assign identity based on associations between target and source variables resulting from deterministic dependencies. We show how these criteria are related to the identity axiom and to previously proposed redundancy measures, and we characterize how they lead to negative PID terms. This constitutes a further step to more explicitly address the role of information identity in the quantification of redundancy. The implications for studying neural coding are discussed.

  18. Reliability Equivalence to Symmetrical UHVDC Transmission Systems Considering Redundant Structure Configuration

    Directory of Open Access Journals (Sweden)

    Xing Jiang

    2018-03-01

    Full Text Available In recent years, the ultra-high voltage direct current (UHVDC transmission system has been developed rapidly for its significant long-distance, high-capacity and low-loss properties. Equipment failures and overall outages of the UHVDC system have increasingly vital influence on the power supply of the receiving end grid. To improve the reliability level of UHVDC systems, a quantitative selection and configuration approach of redundant structures is proposed in this paper, which is based on multi-state reliability equivalence. Specifically, considering the symmetry characteristic of an UHVDC system, a state space model is established as a monopole rather than a bipole, which effectively reduces the state space dimensions to be considered by deducing the reliability merging operator of two poles. Considering the standby effect of AC filters and the recovery effect of converter units, the number of available converter units and corresponding probability are expressed with in universal generating function (UGF form. Then, a sensitivity analysis is performed to quantify the impact of component reliability parameters on system reliability and determine the most specific devices that should be configured in the redundant structure. Finally, a cost-benefit analysis is utilized to help determine the optimal scheme of redundant devices. Case studies are conducted to demonstrate the effectiveness and accuracy of the proposed method. Based on the numerical results, configuring a set of redundant transformers is indicated to be of the greatest significance to improve the reliability level of UHVDC transmission systems.

  19. Redundancy Determination of HVDC MMC Modules

    Directory of Open Access Journals (Sweden)

    Chanki Kim

    2015-08-01

    Full Text Available An availability and a reliability prediction has been made for a high-voltage direct-current (HVDC module of VSC (Voltage Source Converter containing DC/DC converter, gate driver, capacitor and insulated gate bipolar transistors (IGBT. This prediction was made using published failure rates for the electronic equipment. The purpose of this prediction is to determinate the additional module redundancy of VSC and the used method is “binomial failure method”.

  20. Reliability model for common mode failures in redundant safety systems

    International Nuclear Information System (INIS)

    Fleming, K.N.

    1974-12-01

    A method is presented for computing the reliability of redundant safety systems, considering both independent and common mode type failures. The model developed for the computation is a simple extension of classical reliability theory. The feasibility of the method is demonstrated with the use of an example. The probability of failure of a typical diesel-generator emergency power system is computed based on data obtained from U. S. diesel-generator operating experience. The results are compared with reliability predictions based on the assumption that all failures are independent. The comparison shows a significant increase in the probability of redundant system failure, when common failure modes are considered. (U.S.)

  1. Redundant information from thermal illumination: quantum Darwinism in scattered photons

    Energy Technology Data Exchange (ETDEWEB)

    Jess Riedel, C; Zurek, Wojciech H, E-mail: criedel@physics.ucsb.edu [Theory Division, LANL, Los Alamos, NM 87545 (United States)

    2011-07-15

    We study quantum Darwinism, the redundant recording of information about the preferred states of a decohering system by its environment, for an object illuminated by a blackbody. We calculate the quantum mutual information between the object and its photon environment for blackbodies that cover an arbitrary section of the sky. In particular, we demonstrate that more extended sources have a reduced ability to create redundant information about the system, in agreement with previous evidence that initial mixedness of an environment slows-but does not stop-the production of records. We also show that the qualitative results are robust for more general initial states of the system.

  2. Redundant information from thermal illumination: quantum Darwinism in scattered photons

    Science.gov (United States)

    Jess Riedel, C.; Zurek, Wojciech H.

    2011-07-01

    We study quantum Darwinism, the redundant recording of information about the preferred states of a decohering system by its environment, for an object illuminated by a blackbody. We calculate the quantum mutual information between the object and its photon environment for blackbodies that cover an arbitrary section of the sky. In particular, we demonstrate that more extended sources have a reduced ability to create redundant information about the system, in agreement with previous evidence that initial mixedness of an environment slows—but does not stop—the production of records. We also show that the qualitative results are robust for more general initial states of the system.

  3. Development of an automatic subsea blowout preventer stack control system using PLC based SCADA.

    Science.gov (United States)

    Cai, Baoping; Liu, Yonghong; Liu, Zengkai; Wang, Fei; Tian, Xiaojie; Zhang, Yanzhen

    2012-01-01

    An extremely reliable remote control system for subsea blowout preventer stack is developed based on the off-the-shelf triple modular redundancy system. To meet a high reliability requirement, various redundancy techniques such as controller redundancy, bus redundancy and network redundancy are used to design the system hardware architecture. The control logic, human-machine interface graphical design and redundant databases are developed by using the off-the-shelf software. A series of experiments were performed in laboratory to test the subsea blowout preventer stack control system. The results showed that the tested subsea blowout preventer functions could be executed successfully. For the faults of programmable logic controllers, discrete input groups and analog input groups, the control system could give correct alarms in the human-machine interface. Copyright © 2011 ISA. Published by Elsevier Ltd. All rights reserved.

  4. Mediated Instruction and Redundancy Remediation in Sciences in ...

    African Journals Online (AJOL)

    The data were analyzed using t-test statistics. Data analysis revealed that use of mediated instruction significantly removed redundancy for science students also the use of mediated instruction influenced academic achievement of science students in secondary schools. Some of the recommendations include that science ...

  5. Reliability and availability of redundant systems: Computational program and the use of nomograms

    International Nuclear Information System (INIS)

    Signoret, J.P.

    1975-01-01

    A rigorous mathematical approach to determining the reliability and availability of repairable actively redundant systems - (r/m) systems - is considered for the case where the m units comprising the system are identical and the failure and repair rates, lambda and μ respectively, are constant. The method used involves the Markov processes, operator calculus and matrix calculus. All the results of the study are handled by the FIDIAS program, which is a practical tool for calculating with a high degree of precision the reliability or availability of such (r/m) systems whatever the values of m and r. In the FIDIAS-TC version of FIDIAS it is possible to plot curves with a Benson plotter, so that nomograms are produced for rapid and simple determination of the probabilities of failure or non-availability of the (r/m) systems considered. The practical application of nomograms is of interest because (2/3) and (2/4) actively redundant systems are very often used in the control circuits of power reactors. It is shown how easily one can compare these two systems using nomograms and how one can determine lambda or μ as a function of the anticipated result

  6. Experimental study on the supercritical startup of cryogenic loop heat pipes with redundancy design

    International Nuclear Information System (INIS)

    Guo, Yuandong; Lin, Guiping; Bai, Lizhan; Bu, Xueqin; Zhang, Hongxing; He, Jiang; Miao, Jianyin; Wen, Dongsheng

    2016-01-01

    Highlights: • A CLHP-based thermal control system with redundancy design was proposed. • Four possible working modes for the supercritical startup were defined. • Transport line with smaller diameter led to much longer supercritical startup time. • Auxiliary operation of secondary evaporator is necessary for the backup conversion. • Temperature oscillation was observed and investigated in the dual operation mode. - Abstract: Cryogenic loop heat pipe (CLHP) is one of the key components in the future space infrared exploration system, which enables effective and efficient cryogenic heat transport over a long distance with a flexible thermal link. To realize reliable and long life operation, a CLHP-based thermal control system with redundancy design was proposed in this work, where two nitrogen-charged CLHPs were employed to provide cryocooling at 80–100 K. This study focused on the supercritical startup of the CLHPs with redundancy design, and an extensive experimental study under four possible working modes was conducted. Experimental results showed that with 2.5 W applied to the secondary evaporator, each CLHP could realize the supercritical startup successfully in the normal working mode; however, the required time differed a lot because the difference in the transport line diameter significantly affected the cryocooling capacity to the primary evaporator. In the backup conversion mode, instant switch of the two primary evaporators may cause an operation failure, and an auxiliary operation of the secondary evaporator in advance was necessary to make the primary liquid line filled with liquid. In the malfunction conversion mode, the simulated infrared detector had to be first shut down, but the time needed for the backup CLHP to realize the supercritical startup became obviously shorter than that in the normal working mode, because the primary evaporator of the backup CLHP was always in a cryogenic state. In the dual operation mode, the two CLHPs could

  7. Industrial plant electrical systems: Simplicity, reliability, cost savings, redundancies

    International Nuclear Information System (INIS)

    Silvestri, A.; Tommazzolli, F.; Pavia Univ.

    1992-01-01

    This article represents a compact but complete design and construction manual for industrial plant electrical systems. It is to be used by design engineers having prior knowledge of local power supply routes and voltages and regards principally the optimum choice of internal distribution systems which can be radial or single, double ringed or with various network configurations, and with single or multiple supplies, and many or few redundancies. After giving guidelines on the choosing of these options, the manual deals with problematics relevant to suitable cable sizing. A cost benefit benefit analysis method is suggested for the choice of the number of redundancies. Recommendations are given for the choice of transformers, motorized equipment, switch boards and circuit breakers. Reference is made to Italian electrical safety and building codes

  8. Coded aperture imaging with uniformly redundant arrays

    International Nuclear Information System (INIS)

    Fenimore, E.E.; Cannon, T.M.

    1980-01-01

    A system is described which uses uniformly redundant arrays to image non-focusable radiation. The array is used in conjunction with a balanced correlation technique to provide a system with no artifacts so that virtually limitless signal-to-noise ratio is obtained with high transmission characteristics. The array is mosaicked to reduce required detector size over conventional array detectors. 15 claims

  9. Reliability analysis of component-level redundant topologies for solid-state fault current limiter

    Science.gov (United States)

    Farhadi, Masoud; Abapour, Mehdi; Mohammadi-Ivatloo, Behnam

    2018-04-01

    Experience shows that semiconductor switches in power electronics systems are the most vulnerable components. One of the most common ways to solve this reliability challenge is component-level redundant design. There are four possible configurations for the redundant design in component level. This article presents a comparative reliability analysis between different component-level redundant designs for solid-state fault current limiter. The aim of the proposed analysis is to determine the more reliable component-level redundant configuration. The mean time to failure (MTTF) is used as the reliability parameter. Considering both fault types (open circuit and short circuit), the MTTFs of different configurations are calculated. It is demonstrated that more reliable configuration depends on the junction temperature of the semiconductor switches in the steady state. That junction temperature is a function of (i) ambient temperature, (ii) power loss of the semiconductor switch and (iii) thermal resistance of heat sink. Also, results' sensitivity to each parameter is investigated. The results show that in different conditions, various configurations have higher reliability. The experimental results are presented to clarify the theory and feasibility of the proposed approaches. At last, levelised costs of different configurations are analysed for a fair comparison.

  10. On modeling human reliability in space flights - Redundancy and recovery operations

    Science.gov (United States)

    Aarset, M.; Wright, J. F.

    The reliability of humans is of paramount importance to the safety of space flight systems. This paper describes why 'back-up' operators might not be the best solution, and in some cases, might even degrade system reliability. The problem associated with human redundancy calls for special treatment in reliability analyses. The concept of Standby Redundancy is adopted, and psychological and mathematical models are introduced to improve the way such problems can be estimated and handled. In the past, human reliability has practically been neglected in most reliability analyses, and, when included, the humans have been modeled as a component and treated numerically the way technical components are. This approach is not wrong in itself, but it may lead to systematic errors if too simple analogies from the technical domain are used in the modeling of human behavior. In this paper redundancy in a man-machine system will be addressed. It will be shown how simplification from the technical domain, when applied to human components of a system, may give non-conservative estimates of system reliability.

  11. Pauci ex tanto numero: reducing redundancy in multi-model ensembles

    Science.gov (United States)

    Solazzo, E.; Riccio, A.; Kioutsioukis, I.; Galmarini, S.

    2013-02-01

    We explicitly address the fundamental issue of member diversity in multi-model ensembles. To date no attempts in this direction are documented within the air quality (AQ) community, although the extensive use of ensembles in this field. Common biases and redundancy are the two issues directly deriving from lack of independence, undermining the significance of a multi-model ensemble, and are the subject of this study. Shared biases among models will determine a biased ensemble, making therefore essential the errors of the ensemble members to be independent so that bias can cancel out. Redundancy derives from having too large a portion of common variance among the members of the ensemble, producing overconfidence in the predictions and underestimation of the uncertainty. The two issues of common biases and redundancy are analysed in detail using the AQMEII ensemble of AQ model results for four air pollutants in two European regions. We show that models share large portions of bias and variance, extending well beyond those induced by common inputs. We make use of several techniques to further show that subsets of models can explain the same amount of variance as the full ensemble with the advantage of being poorly correlated. Selecting the members for generating skilful, non-redundant ensembles from such subsets proved, however, non-trivial. We propose and discuss various methods of member selection and rate the ensemble performance they produce. In most cases, the full ensemble is outscored by the reduced ones. We conclude that, although independence of outputs may not always guarantee enhancement of scores (but this depends upon the skill being investigated) we discourage selecting the members of the ensemble simply on the basis of scores, that is, independence and skills need to be considered disjointly.

  12. Adaptive control of manipulators handling hazardous waste

    International Nuclear Information System (INIS)

    Colbaugh, R.; Glass, K.

    1994-01-01

    This article focuses on developing a robot control system capable of meeting hazardous waste handling application requirements, and presents as a solution an adaptive strategy for controlling the mechanical impedance of kinematically redundant manipulators. The proposed controller is capable of accurate end-effector impedance control and effective redundancy utilization, does not require knowledge of the complex robot dynamic model or parameter values for the robot or the environment, and is implemented without calculation of the robot inverse transformation. Computer simulation results are given for a four degree of freedom redundant robot under adaptive impedance control. These results indicate that the proposed controller is capable of successfully performing important tasks in robotic waste handling applications. (author) 3 figs., 39 refs

  13. Evaluation of software based redundancy algorithms for the EOS storage system at CERN

    International Nuclear Information System (INIS)

    Peters, Andreas-Joachim; Sindrilaru, Elvin Alin; Zigann, Philipp

    2012-01-01

    EOS is a new disk based storage system used in production at CERN since autumn 2011. It is implemented using the plug-in architecture of the XRootD software framework and allows remote file access via XRootD protocol or POSIX-like file access via FUSE mounting. EOS was designed to fulfill specific requirements of disk storage scalability and IO scheduling performance for LHC analysis use cases. This is achieved by following a strategy of decoupling disk and tape storage as individual storage systems. A key point of the EOS design is to provide high availability and redundancy of files via a software implementation which uses disk-only storage systems without hardware RAID arrays. All this is aimed at reducing the overall cost of the system and also simplifying the operational procedures. This paper presents the advantages and disadvantages of redundancy by hardware (most classical storage installations) in comparison to redundancy by software. The latter is implemented in the EOS system and achieves its goal by spawning data and parity stripes via remote file access over nodes. The gain in redundancy and reliability comes with a trade-off in the following areas: • Increased complexity of the network connectivity • CPU intensive parity computations during file creation and recovery • Performance loss through remote disk coupling An evaluation and performance figures of several redundancy algorithms are presented for dual parity RAID and Reed-Solomon codecs. Moreover, the characteristics and applicability of these algorithms are discussed in the context of reliable data storage systems.

  14. Processing bimodal stimulus information under alcohol: is there a risk to being redundant?

    Science.gov (United States)

    Fillmore, Mark T

    2010-10-01

    The impairing effects of alcohol are especially pronounced in environments that involve dividing attention across two or more stimuli. However, studies in cognitive psychology have identified circumstances in which the presentation of multiple stimuli can actually facilitate performance. The "redundant signal effect" (RSE) refers to the observation that individuals respond more quickly when information is presented as redundant, bimodal stimuli (e.g., aurally and visually), rather than as a single stimulus presented to either modality alone. The present study tested the hypothesis that the response facilitation attributed to RSE could reduce the degree to which alcohol slows information processing. Two experiments are reported. Experiment 1 demonstrated the validity of a reaction time model of RSE by showing that adults (N = 15) responded more quickly to redundant, bimodal stimuli (visual + aural) versus either stimuli presented individually. Experiment 2 used the RSE model to test the reaction time performance of 20 adults following three alcohol doses (0.0 g/kg, 0.45 g/kg, and 0.65 g/kg). Results showed that alcohol slowed reaction time in a general dose-dependent manner in all three stimulus conditions with the reaction time (RT) speed-advantage of the redundant signal being maintained, even under the highest dose of alcohol. Evidence for an RT advantage to bimodal stimuli under alcohol challenges the general assumption that alcohol impairment is intensified in multistimulus environments. The current study provides a useful model to investigate how drug effects on behavior might be altered in contexts that involve redundant response signals.

  15. Development of high reliability dual redundant FADEC. Koshinraisei nijukei FADEC no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Endo, M [Ishikawajima-Harima Heavy Industries, Co. Ltd., Tokyo (Japan)

    1994-05-01

    The control unit of gas turbine for the aircraft jet engine use must draw overall performance in compliance with the thrust commanded by the pilot under all flying conditions of the engine. High reliability is required in flight safety. The present paper explains a developed unit of dual redundant FADEC (full authority digital electronic control) and high-density mounting technology for the electronic devices required by the FADEC. The FADEC unit is composed of two hardware systems with their respective microprocessors of the same structure. Each of both systems can solely control the engine, while they are both commanded by a necessary signal for the dual system operation and connected through a digital by-pass which can exchange the input/output data between them. For the operational confirmation of FADEC unit, its control characteristics were inspected by intentionally putting it out of order at the time of engine acceleration/deceleration and other transient operations. The control system could be switched without control characteristics lost of the engine. 9 figs., 2 tabs.

  16. Network Gateway Technology: The Issue of Redundancy towards ...

    African Journals Online (AJOL)

    Everyone connected to the Internet is concerned about two basic things: the availability of network services and the speed of the network. Network gateway redundancy technology falls within these categories and happens to be one of the newest technologies which only few companies, such as mobile companies and ...

  17. Interactions of Aircraft Design and Control: Actuators Sizing and Optimization for an Unstable Blended Wing-Body

    OpenAIRE

    Denieul , Yann; Alazard , Daniel; Bordeneuve-Guibé , Joël; Toussaint , Clément; Taquin , Gilles

    2015-01-01

    International audience; In this paper the problem of integrated design and control for a civil blended wing-body aircraft is addressed. Indeed this configuration faces remarkable challenges relatedto handling qualities: namely the aircraft configuration in this study features a strong longitudinal instability for some specific flight points. Moreover it may lack control efficiency despite large and redundant movables. Stabilizing such a configuration may then lead to high control surfaces rat...

  18. Retraction: Redundant Publication of the article Dental caries and ...

    African Journals Online (AJOL)

    Retraction: Redundant Publication of the article Dental caries and oral health practices among 12 year old children in Nairobi West and Mathira West Districts, Kenya. Gladwell Gathecha et al. The Pan African Medical Journal. 2012;12:42.

  19. Diabetes classification using a redundancy reduction preprocessor

    Directory of Open Access Journals (Sweden)

    Áurea Celeste Ribeiro

    Full Text Available Introduction Diabetes patients can benefit significantly from early diagnosis. Thus, accurate automated screening is becoming increasingly important due to the wide spread of that disease. Previous studies in automated screening have found a maximum accuracy of 92.6%. Methods This work proposes a classification methodology based on efficient coding of the input data, which is carried out by decreasing input data redundancy using well-known ICA algorithms, such as FastICA, JADE and INFOMAX. The classifier used in the task to discriminate diabetics from non-diaibetics is the one class support vector machine. Classification tests were performed using noninvasive and invasive indicators. Results The results suggest that redundancy reduction increases one-class support vector machine performance when discriminating between diabetics and nondiabetics up to an accuracy of 98.47% while using all indicators. By using only noninvasive indicators, an accuracy of 98.28% was obtained. Conclusion The ICA feature extraction improves the performance of the classifier in the data set because it reduces the statistical dependence of the collected data, which increases the ability of the classifier to find accurate class boundaries.

  20. Structural Equation Models in a Redundancy Analysis Framework With Covariates.

    Science.gov (United States)

    Lovaglio, Pietro Giorgio; Vittadini, Giorgio

    2014-01-01

    A recent method to specify and fit structural equation modeling in the Redundancy Analysis framework based on so-called Extended Redundancy Analysis (ERA) has been proposed in the literature. In this approach, the relationships between the observed exogenous variables and the observed endogenous variables are moderated by the presence of unobservable composites, estimated as linear combinations of exogenous variables. However, in the presence of direct effects linking exogenous and endogenous variables, or concomitant indicators, the composite scores are estimated by ignoring the presence of the specified direct effects. To fit structural equation models, we propose a new specification and estimation method, called Generalized Redundancy Analysis (GRA), allowing us to specify and fit a variety of relationships among composites, endogenous variables, and external covariates. The proposed methodology extends the ERA method, using a more suitable specification and estimation algorithm, by allowing for covariates that affect endogenous indicators indirectly through the composites and/or directly. To illustrate the advantages of GRA over ERA we propose a simulation study of small samples. Moreover, we propose an application aimed at estimating the impact of formal human capital on the initial earnings of graduates of an Italian university, utilizing a structural model consistent with well-established economic theory.

  1. Preliminary results from comparisons of redundant tiltmeters at three sites in central california

    Science.gov (United States)

    Mortensen, C.E.; Johnston, M.J.S.

    1979-01-01

    The U.S. Geological Survey has been operating a network of shallow-borehole tiltmeters in central California since June 1973. At six sites redundant instruments have been installed as a check on data coherency. These include the Sage Ranch, Tres Pinos, New Idria, Aromas, Bear Valley and San Juan Bautista tiltmeter sites. Preliminary results from the comparison of redundant data from the Aromas, Bear Valley and San Juan Bautista sites for periods of eight, three and seven months respectively, suggest that short period tilt signals in the range 5 min < T < 3-5 h and ranging in amplitude from 5 ?? 10-8 to 10-6 rad, but not including step offsets, show excellent agreement on closely spaced instruments. Agreement is not as good in this period range for instruments at San Juan Bautista with a separation of 200 m. Signals of interest observed in this period range include coseismic tilts, teleseisms and tilts associated with creep events. Tilt signals in the period range 3-5 h < T < 2- 5 weeks are not always coherent at all three of the redundant tilt sites studied. Tilt signals in this period range have amplitudes up to 5 ?? 10-6 rad and wavelengths down to at least the instrument separation at the closely spaced sites (~several meters). Regarding longerterm coherency, the instruments at San Juan Bautista with 200-m spacing, agree within 0.5 ??rad for the N-S component and 0.7 jurad for the E-W component for a period of two months. The closely spaced redundant instruments at Aromas agree within 2 ??rad for the N-S component and 1 ??rad for the E-W component for the eight-month period of operation. Data from the three sites have been checked for effects of temperature, atmospheric pressure and rainfall. The latter appears to be critically site dependent. The worst case tilts for 1 inch of rainfall can be more than 1 jurad with a duration of a few days to a week. Typical rain-induced tilts are less than 0.3 ??rad for 1 inch of rain. The two instruments at the Sage Ranch

  2. Synergetic and Redundant Information Flow Detected by Unnormalized Granger Causality: Application to Resting State fMRI.

    Science.gov (United States)

    Stramaglia, Sebastiano; Angelini, Leonardo; Wu, Guorong; Cortes, Jesus M; Faes, Luca; Marinazzo, Daniele

    2016-12-01

    We develop a framework for the analysis of synergy and redundancy in the pattern of information flow between subsystems of a complex network. The presence of redundancy and/or synergy in multivariate time series data renders difficulty to estimate the neat flow of information from each driver variable to a given target. We show that adopting an unnormalized definition of Granger causality, one may put in evidence redundant multiplets of variables influencing the target by maximizing the total Granger causality to a given target, over all the possible partitions of the set of driving variables. Consequently, we introduce a pairwise index of synergy which is zero when two independent sources additively influence the future state of the system, differently from previous definitions of synergy. We report the application of the proposed approach to resting state functional magnetic resonance imaging data from the Human Connectome Project showing that redundant pairs of regions arise mainly due to space contiguity and interhemispheric symmetry, while synergy occurs mainly between nonhomologous pairs of regions in opposite hemispheres. Redundancy and synergy, in healthy resting brains, display characteristic patterns, revealed by the proposed approach. The pairwise synergy index, here introduced, maps the informational character of the system at hand into a weighted complex network: the same approach can be applied to other complex systems whose normal state corresponds to a balance between redundant and synergetic circuits.

  3. Network Gateway Technology: The Issue of Redundancy towards ...

    African Journals Online (AJOL)

    The Internet has provided advancement in the areas of network and networking facilities. Everyone connected to the Internet is concerned about two basic things: the availability of network services and the speed of the network. Network gateway redundancy technology falls within these categories and happens to be one of ...

  4. The Effect of Antenna Position Errors on Redundant-Baseline Calibration of HERA

    Science.gov (United States)

    Orosz, Naomi; Dillon, Joshua; Ewall-Wice, Aaron; Parsons, Aaron; HERA Collaboration

    2018-01-01

    HERA (the Hydrogen Epoch of Reionization Array) is a large, highly-redundant radio interferometer in South Africa currently being built out to 350 14-m dishes. Its mission is to probe large scale structure during and prior to the epoch of reionization using the 21 cm hyperfine transition of neutral hydrogen. The array is designed to be calibrated using redundant baselines of known lengths. However, the dishes can deviate from ideal positions, with errors on the order of a few centimeters. This potentially increases foreground contamination of the 21 cm power spectrum in the cleanest part of Fourier space. The calibration algorithm treats groups of baselines that should be redundant, but are not due to position errors, as if they actually are. Accurate, precise calibration is critical because the foreground signals are 100,000 times stronger than the reionization signal. We explain the origin of this effect and discuss weighting strategies to mitigate it.

  5. Polarized Redundant-Baseline Calibration for 21 cm Cosmology Without Adding Spectral Structure

    Science.gov (United States)

    Dillon, Joshua S.; Kohn, Saul A.; Parsons, Aaron R.; Aguirre, James E.; Ali, Zaki S.; Bernardi, Gianni; Kern, Nicholas S.; Li, Wenyang; Liu, Adrian; Nunhokee, Chuneeta D.; Pober, Jonathan C.

    2018-04-01

    21 cm cosmology is a promising new probe of the evolution of visible matter in our universe, especially during the poorly-constrained Cosmic Dawn and Epoch of Reionization. However, in order to separate the 21 cm signal from bright astrophysical foregrounds, we need an exquisite understanding of our telescopes so as to avoid adding spectral structure to spectrally-smooth foregrounds. One powerful calibration method relies on repeated simultaneous measurements of the same interferometric baseline to solve for the sky signal and for instrumental parameters simultaneously. However, certain degrees of freedom are not constrained by asserting internal consistency between redundant measurements. In this paper, we review the origin of these degeneracies of redundant-baseline calibration and demonstrate how they can source unwanted spectral structure in our measurement and show how to eliminate that additional, artificial structure. We also generalize redundant calibration to dual-polarization instruments, derive the degeneracy structure, and explore the unique challenges to calibration and preserving spectral smoothness presented by a polarized measurement.

  6. Analytical Redundancy Design for Aeroengine Sensor Fault Diagnostics Based on SROS-ELM

    Directory of Open Access Journals (Sweden)

    Jun Zhou

    2016-01-01

    Full Text Available Analytical redundancy technique is of great importance to guarantee the reliability and safety of aircraft engine system. In this paper, a machine learning based aeroengine sensor analytical redundancy technique is developed and verified through hardware-in-the-loop (HIL simulation. The modified online sequential extreme learning machine, selective updating regularized online sequential extreme learning machine (SROS-ELM, is employed to train the model online and estimate sensor measurements. It selectively updates the output weights of neural networks according to the prediction accuracy and the norm of output weight vector, tackles the problems of singularity and ill-posedness by regularization, and adopts a dual activation function in the hidden nodes combing neural and wavelet theory to enhance prediction capability. The experimental results verify the good generalization performance of SROS-ELM and show that the developed analytical redundancy technique for aeroengine sensor fault diagnosis based on SROS-ELM is effective and feasible.

  7. Synchronization and fault-masking in redundant real-time systems

    Science.gov (United States)

    Krishna, C. M.; Shin, K. G.; Butler, R. W.

    1983-01-01

    A real time computer may fail because of massive component failures or not responding quickly enough to satisfy real time requirements. An increase in redundancy - a conventional means of improving reliability - can improve the former but can - in some cases - degrade the latter considerably due to the overhead associated with redundancy management, namely the time delay resulting from synchronization and voting/interactive consistency techniques. The implications of synchronization and voting/interactive consistency algorithms in N-modular clusters on reliability are considered. All these studies were carried out in the context of real time applications. As a demonstrative example, we have analyzed results from experiments conducted at the NASA Airlab on the Software Implemented Fault Tolerance (SIFT) computer. This analysis has indeed indicated that in most real time applications, it is better to employ hardware synchronization instead of software synchronization and not allow reconfiguration.

  8. Introducing "biophysical redundancy": the global status and past evolution of unused water, land and productivity resources for food production

    Science.gov (United States)

    Fader, Marianela

    2017-04-01

    Countries have different resilience to sudden and long-term changes in food demand and supply. An important part of this resilience is the degree of biophysical redundancy, defined as the potential food production of 'spare land', available water resources (i.e., not already used for human activities), as well as production increases through yield gap closure on cultivated areas and potential agricultural areas. The presentation will show the results of a recently published paper1 on the evolution of biophysical redundancy for agricultural production at country level, from 1992 to 2012. Results indicate that in 2012, the biophysical redundancy of 75 (48) countries, mainly in North Africa, Western Europe, the Middle East and Asia, was insufficient to produce the caloric nutritional needs for at least 50% (25%) of their population during a year. Biophysical redundancy has decreased in the last two decades in 102 out of 155 countries, 11 of these went from high to limited redundancy, and nine of these from limited to very low redundancy. Although the variability of the drivers of change across different countries is high, improvements in yield and population growth have a clear impact on the decreases of redundancy towards the very low redundancy category. We took a more detailed look at countries classified as 'Low Income Economies (LIEs)' since they are particularly vulnerable to domestic or external food supply changes, due to their limited capacity to offset for food supply decreases with higher purchasing power on the international market. Currently, nine LIEs have limited or very low biophysical redundancy. Many of these showed a decrease in redundancy over the last two decades, which is not always linked with improvements in per capita food availability.

  9. RSAT matrix-clustering: dynamic exploration and redundancy reduction of transcription factor binding motif collections.

    Science.gov (United States)

    Castro-Mondragon, Jaime Abraham; Jaeger, Sébastien; Thieffry, Denis; Thomas-Chollier, Morgane; van Helden, Jacques

    2017-07-27

    Transcription factor (TF) databases contain multitudes of binding motifs (TFBMs) from various sources, from which non-redundant collections are derived by manual curation. The advent of high-throughput methods stimulated the production of novel collections with increasing numbers of motifs. Meta-databases, built by merging these collections, contain redundant versions, because available tools are not suited to automatically identify and explore biologically relevant clusters among thousands of motifs. Motif discovery from genome-scale data sets (e.g. ChIP-seq) also produces redundant motifs, hampering the interpretation of results. We present matrix-clustering, a versatile tool that clusters similar TFBMs into multiple trees, and automatically creates non-redundant TFBM collections. A feature unique to matrix-clustering is its dynamic visualisation of aligned TFBMs, and its capability to simultaneously treat multiple collections from various sources. We demonstrate that matrix-clustering considerably simplifies the interpretation of combined results from multiple motif discovery tools, and highlights biologically relevant variations of similar motifs. We also ran a large-scale application to cluster ∼11 000 motifs from 24 entire databases, showing that matrix-clustering correctly groups motifs belonging to the same TF families, and drastically reduced motif redundancy. matrix-clustering is integrated within the RSAT suite (http://rsat.eu/), accessible through a user-friendly web interface or command-line for its integration in pipelines. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

  10. Redundancy Factors for the Seismic Design of Ductile Reinforced Concrete Chevron Braced Frames

    Directory of Open Access Journals (Sweden)

    Eber Alberto Godínez-Domínguez

    Full Text Available Abstract In this paper the authors summarize the results of a study devoted to assess, using nonlinear static analyses, the impact of increasing the structural redundancy in ductile moment-resisting reinforced concrete concentric braced frames structures (RC-MRCBFs. Among the studied variables were the number of stories and the number of bays. Results obtained were compared with the currently proposed values in the Manual of Civil Structures (MOC-08, a model code of Mexico. The studied frames have 4, 8, 12 and 16-story with a story height h=3.5 m. and a fixed length L=12 m., where 1, 2, 3 or 4 bays have to be located. RC-MRCBFs were assumed to be located in soft soil conditions in Mexico City and were designed using a capacity design methodology adapted to general requirements of the seismic, reinforced concrete and steel guidelines of Mexican Codes. From the results obtained in this study it is possible to conclude that a different effect is observed in overstrength redundancy factors respect to ductility redundancy factors due to an increase of the bay number considered. Also, the structural redundancy factors obtained for this particular structural system varies respect to the currently proposed in MOC-08.

  11. Triple3 Redundant Spacecraft Subsystems (T3RSS), Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Redefine Technologies, along with researchers at the University of Colorado, will use three redundancy methods to decrease the susceptibility of a spacecraft, on a...

  12. Temporal information partitioning: Characterizing synergy, uniqueness, and redundancy in interacting environmental variables

    Science.gov (United States)

    Goodwell, Allison E.; Kumar, Praveen

    2017-07-01

    Information theoretic measures can be used to identify nonlinear interactions between source and target variables through reductions in uncertainty. In information partitioning, multivariate mutual information is decomposed into synergistic, unique, and redundant components. Synergy is information shared only when sources influence a target together, uniqueness is information only provided by one source, and redundancy is overlapping shared information from multiple sources. While this partitioning has been applied to provide insights into complex dependencies, several proposed partitioning methods overestimate redundant information and omit a component of unique information because they do not account for source dependencies. Additionally, information partitioning has only been applied to time-series data in a limited context, using basic pdf estimation techniques or a Gaussian assumption. We develop a Rescaled Redundancy measure (Rs) to solve the source dependency issue, and present Gaussian, autoregressive, and chaotic test cases to demonstrate its advantages over existing techniques in the presence of noise, various source correlations, and different types of interactions. This study constitutes the first rigorous application of information partitioning to environmental time-series data, and addresses how noise, pdf estimation technique, or source dependencies can influence detected measures. We illustrate how our techniques can unravel the complex nature of forcing and feedback within an ecohydrologic system with an application to 1 min environmental signals of air temperature, relative humidity, and windspeed. The methods presented here are applicable to the study of a broad range of complex systems composed of interacting variables.

  13. Analysis of transitions at two-fold redundant sites in mammalian genomes. Transition redundant approach-to-equilibrium (TREx distance metrics

    Directory of Open Access Journals (Sweden)

    Liberles David A

    2006-03-01

    Full Text Available Abstract Background The exchange of nucleotides at synonymous sites in a gene encoding a protein is believed to have little impact on the fitness of a host organism. This should be especially true for synonymous transitions, where a pyrimidine nucleotide is replaced by another pyrimidine, or a purine is replaced by another purine. This suggests that transition redundant exchange (TREx processes at the third position of conserved two-fold codon systems might offer the best approximation for a neutral molecular clock, serving to examine, within coding regions, theories that require neutrality, determine whether transition rate constants differ within genes in a single lineage, and correlate dates of events recorded in genomes with dates in the geological and paleontological records. To date, TREx analysis of the yeast genome has recognized correlated duplications that established a new metabolic strategies in fungi, and supported analyses of functional change in aromatases in pigs. TREx dating has limitations, however. Multiple transitions at synonymous sites may cause equilibration and loss of information. Further, to be useful to correlate events in the genomic record, different genes within a genome must suffer transitions at similar rates. Results A formalism to analyze divergence at two fold redundant codon systems is presented. This formalism exploits two-state approach-to-equilibrium kinetics from chemistry. This formalism captures, in a single equation, the possibility of multiple substitutions at individual sites, avoiding any need to "correct" for these. The formalism also connects specific rate constants for transitions to specific approximations in an underlying evolutionary model, including assumptions that transition rate constants are invariant at different sites, in different genes, in different lineages, and at different times. Therefore, the formalism supports analyses that evaluate these approximations. Transitions at synonymous

  14. Distributed and recoverable digital control system

    Science.gov (United States)

    Stange, Kent (Inventor); Hess, Richard (Inventor); Kelley, Gerald B (Inventor); Rogers, Randy (Inventor)

    2010-01-01

    A real-time multi-tasking digital control system with rapid recovery capability is disclosed. The control system includes a plurality of computing units comprising a plurality of redundant processing units, with each of the processing units configured to generate one or more redundant control commands. One or more internal monitors are employed for detecting data errors in the control commands. One or more recovery triggers are provided for initiating rapid recovery of a processing unit if data errors are detected. The control system also includes a plurality of actuator control units each in operative communication with the computing units. The actuator control units are configured to initiate a rapid recovery if data errors are detected in one or more of the processing units. A plurality of smart actuators communicates with the actuator control units, and a plurality of redundant sensors communicates with the computing units.

  15. Risk-based replacement strategies for redundant deteriorating reinforced concrete pipe networks

    International Nuclear Information System (INIS)

    Adey, B.; Bernard, O.; Gerard, B.

    2003-01-01

    This paper gives an example of how predictive models of the deterioration of reinforced concrete pipes and the consequences of failure can be used to develop risk-based replacement strategies for redundant reinforced concrete pipe networks. It also shows how an accurate deterioration prediction can lead to a reduction of agency costs, and illustrates the limitation of the incremental intervention step algorithm. The main conclusion is that the use of predictive models, such as those developed by Oxand S.A., in the determination of replacement strategies for redundant reinforced concrete pipe networks can lead to a significant reduction in overall costs for the owner of the structure. (author)

  16. Probability Model for Data Redundancy Detection in Sensor Networks

    Directory of Open Access Journals (Sweden)

    Suman Kumar

    2009-01-01

    Full Text Available Sensor networks are made of autonomous devices that are able to collect, store, process and share data with other devices. Large sensor networks are often redundant in the sense that the measurements of some nodes can be substituted by other nodes with a certain degree of confidence. This spatial correlation results in wastage of link bandwidth and energy. In this paper, a model for two associated Poisson processes, through which sensors are distributed in a plane, is derived. A probability condition is established for data redundancy among closely located sensor nodes. The model generates a spatial bivariate Poisson process whose parameters depend on the parameters of the two individual Poisson processes and on the distance between the associated points. The proposed model helps in building efficient algorithms for data dissemination in the sensor network. A numerical example is provided investigating the advantage of this model.

  17. Functional redundancy and sensitivity of fish assemblages in European rivers, lakes and estuarine ecosystems.

    Science.gov (United States)

    Teichert, Nils; Lepage, Mario; Sagouis, Alban; Borja, Angel; Chust, Guillem; Ferreira, Maria Teresa; Pasquaud, Stéphanie; Schinegger, Rafaela; Segurado, Pedro; Argillier, Christine

    2017-12-14

    The impact of species loss on ecosystems functioning depends on the amount of trait similarity between species, i.e. functional redundancy, but it is also influenced by the order in which species are lost. Here we investigated redundancy and sensitivity patterns across fish assemblages in lakes, rivers and estuaries. Several scenarios of species extinction were simulated to determine whether the loss of vulnerable species (with high propensity of extinction when facing threats) causes a greater functional alteration than random extinction. Our results indicate that the functional redundancy tended to increase with species richness in lakes and rivers, but not in estuaries. We demonstrated that i) in the three systems, some combinations of functional traits are supported by non-redundant species, ii) rare species in rivers and estuaries support singular functions not shared by dominant species, iii) the loss of vulnerable species can induce greater functional alteration in rivers than in lakes and estuaries. Overall, the functional structure of fish assemblages in rivers is weakly buffered against species extinction because vulnerable species support singular functions. More specifically, a hotspot of functional sensitivity was highlighted in the Iberian Peninsula, which emphasizes the usefulness of quantitative criteria to determine conservation priorities.

  18. Redundancy in Anaerobic Digestion Microbiomes during Disturbances by the Antibiotic Monensin

    Science.gov (United States)

    Spirito, Catherine M.; Daly, Sarah E.; Werner, Jeffrey J.

    2018-01-01

    ABSTRACT The antibiotic monensin is fed to dairy cows to increase milk production efficiency. A fraction of this monensin is excreted into the cow manure. Previous studies have found that cow manure containing monensin can negatively impact the performance of anaerobic digesters, especially upon first introduction. Few studies have examined whether the anaerobic digester microbiome can adapt to monensin during the operating time. Here, we conducted a long-term time series study of four lab-scale anaerobic digesters fed with cow manure. We examined changes in both the microbiome composition and function of the anaerobic digesters when subjected to the dairy antibiotic monensin. In our digesters, monensin was not rapidly degraded under anaerobic conditions. The two anaerobic digesters that were subjected to manure from monensin feed-dosed cows exhibited relatively small changes in microbiome composition and function due to relatively low monensin concentrations. At higher concentrations of monensin, which we dosed directly to control manure (from dairy cows without monensin), we observed major changes in the microbiome composition and function of two anaerobic digesters. A rapid introduction of monensin to one of these anaerobic digesters led to the impairment of methane production. Conversely, more gradual additions of the same concentrations of monensin to the other anaerobic digester led to the adaptation of the anaerobic digester microbiomes to the relatively high monensin concentrations. A member of the candidate OP11 (Microgenomates) phylum arose in this anaerobic digester and appeared to be redundant with certain Bacteroidetes phylum members, which previously were dominating. IMPORTANCE Monensin is a common antibiotic given to dairy cows in the United States and is partly excreted with dairy manure. An improved understanding of how monensin affects the anaerobic digester microbiome composition and function is important to prevent process failure for farm

  19. Control Surface Fault Diagnosis for Small Autonomous Aircraft

    DEFF Research Database (Denmark)

    Hansen, Søren; Blanke, Mogens

    2011-01-01

    Small unmanned aerial vehicles require a large degree of fault-tolerance in order to fulfil their duties in an satisfactory way, both with respect to economy and safety in operation. Small aerial vehicles are commonly constructed without much redundancy in hardware, primarily for reasons of cost...

  20. Testing the significance of canonical axes in redundancy analysis

    NARCIS (Netherlands)

    Legendre, P.; Oksanen, J.; Braak, ter C.J.F.

    2011-01-01

    1. Tests of significance of the individual canonical axes in redundancy analysis allow researchers to determine which of the axes represent variation that can be distinguished from random. Variation along the significant axes can be mapped, used to draw biplots or interpreted through subsequent

  1. Stabilization Methods for the Integration of DAE in the Presence of Redundant Constraints

    International Nuclear Information System (INIS)

    Neto, Maria Augusta; Ambrosio, Jorge

    2003-01-01

    The use of multibody formulations based on Cartesian or natural coordinates lead to sets of differential-algebraic equations that have to be solved. The difficulty in providing compatible initial positions and velocities for a general spatial multibody model and the finite precision of such data result in initial errors that must be corrected during the forward dynamic solution of the system equations of motion.As the position and velocity constraint equations are not explicitly involved in the solution procedure, any integration error leads to the violation of these equations in the long run. Another problem that is very often impossible to avoid is the presence of redundant constraints.Even with no initial redundancy it is possible for some systems to achieve singular configurations in which kinematic constraints become temporarily redundant. In this work several procedures to stabilize the solution of the equations of motion and to handle redundant constraints are revisited. The Baumgarte stabilization, augmented Lagrangian and coordinate partitioning methods are discussed in terms of their efficiency and computational costs. The LU factorization with full pivoting of the Jacobian matrix directs the choice of the set of independent coordinates, required by the coordinate partitioning method.Even when no particular stabilization method is used, a Newton-Raphson iterative procedure is still required in the initial time step to correct the initial positions and velocities, thus requiring the selection of the independent coordinates. However, this initial selection does not guarantee that during the motion of the system other constraints do not become redundant. Two procedures based on the single value decomposition and Gram-Schmidt orthogonalization are revisited for the purpose. The advantages and drawbacks of the different procedures,used separately or in conjunction with each other and their computational costs are finally discussed

  2. Functional over-redundancy and high functional vulnerability in global fish faunas on tropical reefs.

    Science.gov (United States)

    Mouillot, David; Villéger, Sébastien; Parravicini, Valeriano; Kulbicki, Michel; Arias-González, Jesus Ernesto; Bender, Mariana; Chabanet, Pascale; Floeter, Sergio R; Friedlander, Alan; Vigliola, Laurent; Bellwood, David R

    2014-09-23

    When tropical systems lose species, they are often assumed to be buffered against declines in functional diversity by the ability of the species-rich biota to display high functional redundancy: i.e., a high number of species performing similar functions. We tested this hypothesis using a ninefold richness gradient in global fish faunas on tropical reefs encompassing 6,316 species distributed among 646 functional entities (FEs): i.e., unique combinations of functional traits. We found that the highest functional redundancy is located in the Central Indo-Pacific with a mean of 7.9 species per FE. However, this overall level of redundancy is disproportionately packed into few FEs, a pattern termed functional over-redundancy (FOR). For instance, the most speciose FE in the Central Indo-Pacific contains 222 species (out of 3,689) whereas 38% of FEs (180 out of 468) have no functional insurance with only one species. Surprisingly, the level of FOR is consistent across the six fish faunas, meaning that, whatever the richness, over a third of the species may still be in overrepresented FEs whereas more than one third of the FEs are left without insurance, these levels all being significantly higher than expected by chance. Thus, our study shows that, even in high-diversity systems, such as tropical reefs, functional diversity remains highly vulnerable to species loss. Although further investigations are needed to specifically address the influence of redundant vs. vulnerable FEs on ecosystem functioning, our results suggest that the promised benefits from tropical biodiversity may not be as strong as previously thought.

  3. Redundancy-free single-particle equation-of-motion method for nuclei. Pt. 1

    International Nuclear Information System (INIS)

    Rolnick, P.; Goswami, A.; Oregon Univ., Eugene

    1986-01-01

    The problem of coupling an odd nucleon to the collective states of an even core is considered in the intermediate-coupling limit. It is now well known that such intermediate-coupling calculations in spherical open-shell nuclei necessitate the inclusion of ground-state correlation or backward coupling which gives rise to an overcomplete basic set of states for the diagonalization of the hamiltonian. In a recent letter, we have derived a technique to free the single-particle equation-of-motion method of redundancy. Here we shall apply this redundancy-free equation-of-motion method to intermediate-coupling calculations in two regions of near-spherical odd-mass nuclei where forward coupling alone has not been successful. It is shown that qualitative effects of backward coupling previously reported are not spurious effects of double counting, although they are significantly modified by the removal of redundancy. We also discuss what further modifications of the theory will be needed in order to treat the dynamical interplay of collective and single-particle modes in nuclei self-consistently on the same footing. (orig.)

  4. Quantifying the value of redundant measurements at GCOS Reference Upper-Air Network sites

    Directory of Open Access Journals (Sweden)

    F. Madonna

    2014-11-01

    Full Text Available The potential for measurement redundancy to reduce uncertainty in atmospheric variables has not been investigated comprehensively for climate observations. We evaluated the usefulness of entropy and mutual correlation concepts, as defined in information theory, for quantifying random uncertainty and redundancy in time series of the integrated water vapour (IWV and water vapour mixing ratio profiles provided by five highly instrumented GRUAN (GCOS, Global Climate Observing System, Reference Upper-Air Network stations in 2010–2012. Results show that the random uncertainties on the IWV measured with radiosondes, global positioning system, microwave and infrared radiometers, and Raman lidar measurements differed by less than 8%. Comparisons of time series of IWV content from ground-based remote sensing instruments with in situ soundings showed that microwave radiometers have the highest redundancy with the IWV time series measured by radiosondes and therefore the highest potential to reduce the random uncertainty of the radiosondes time series. Moreover, the random uncertainty of a time series from one instrument can be reduced by ~ 60% by constraining the measurements with those from another instrument. The best reduction of random uncertainty is achieved by conditioning Raman lidar measurements with microwave radiometer measurements. Specific instruments are recommended for atmospheric water vapour measurements at GRUAN sites. This approach can be applied to the study of redundant measurements for other climate variables.

  5. The Evolution of Functionally Redundant Species; Evidence from Beetles

    NARCIS (Netherlands)

    Scheffer, M.; Vergnon, R.O.H.; Nes, van E.H.; Cuppen, J.G.M.; Peeters, E.T.H.M.; Leijs, R.; Nilsson, A.N.

    2015-01-01

    While species fulfill many different roles in ecosystems, it has been suggested that numerous species might actually share the same function in a near neutral way. So-far, however, it is unclear whether such functional redundancy really exists. We scrutinize this question using extensive data on the

  6. The Evolution of Functionally Redundant Species; Evidence from Beetles.

    Directory of Open Access Journals (Sweden)

    Marten Scheffer

    Full Text Available While species fulfill many different roles in ecosystems, it has been suggested that numerous species might actually share the same function in a near neutral way. So-far, however, it is unclear whether such functional redundancy really exists. We scrutinize this question using extensive data on the world's 4168 species of diving beetles. We show that across the globe these animals have evolved towards a small number of regularly-spaced body sizes, and that locally co-existing species are either very similar in size or differ by at least 35%. Surprisingly, intermediate size differences (10-20% are rare. As body-size strongly reflects functional aspects such as the food that these generalist predators can eat, these beetles thus form relatively distinct groups of functional look-a-likes. The striking global regularity of these patterns support the idea that a self-organizing process drives such species-rich groups to self-organize evolutionary into clusters where functional redundancy ensures resilience through an insurance effect.

  7. Formulation of a strategy for monitoring control integrity in critical digital control systems

    Science.gov (United States)

    Belcastro, Celeste M.; Fischl, Robert; Kam, Moshe

    1991-01-01

    Advanced aircraft will require flight critical computer systems for stability augmentation as well as guidance and control that must perform reliably in adverse, as well as nominal, operating environments. Digital system upset is a functional error mode that can occur in electromagnetically harsh environments, involves no component damage, can occur simultaneously in all channels of a redundant control computer, and is software dependent. A strategy is presented for dynamic upset detection to be used in the evaluation of critical digital controllers during the design and/or validation phases of development. Critical controllers must be able to be used in adverse environments that result from disturbances caused by an electromagnetic source such as lightning, high intensity radiated field (HIRF), and nuclear electromagnetic pulses (NEMP). The upset detection strategy presented provides dynamic monitoring of a given control computer for degraded functional integrity that can result from redundancy management errors and control command calculation error that could occur in an electromagnetically harsh operating environment. The use is discussed of Kalman filtering, data fusion, and decision theory in monitoring a given digital controller for control calculation errors, redundancy management errors, and control effectiveness.

  8. A model for the coupling of failure rates in a redundant system

    International Nuclear Information System (INIS)

    Kleppmann, W.G.; Wutschig, R.

    1986-01-01

    A model is developed which takes into acount the coupling between failure rates or identical components in different redundancies of a safety system, i.e., the fact that the failure rates of identical components subjected to the same operating conditions will scatter less than the failure rates of any two components of the same type. It is shown that with increasing coupling the expectation value and the variance of the distribution of the failure probability of the redundant system increases. A consistent way to incorporate operating experience in a Bayesian framework is developed and the reults are presented. (orig.)

  9. Neuromechanical Control for Hexapedal Robot Walking on Challenging Surfaces and Surface Classification

    DEFF Research Database (Denmark)

    Xiong, Xiaofeng; Wörgötter, Florentin; Manoonpong, Poramate

    2014-01-01

    The neuromechanical control principles of animal locomotion provide good insights for the development of bio-inspired legged robots for walking on challenging surfaces. Based on such principles, we developed a neuromechanical controller consisting of a modular neural network (MNN) and of virtual...... agonist–antagonist muscle mechanisms (VAAMs). The controller allows for variable compliant leg motions of a hexapod robot, thereby leading to energy-efficient walking on different surfaces. Without any passive mechanisms or torque and position feedback at each joint, the variable compliant leg motions...... are achieved by only changing the stiffness parameters of the VAAMs. In addition, six surfaces can be also classified by observing the motor signals generated by the controller. The performance of the controller is tested on a physical hexapod robot. Experimental results show that it can effectively walk...

  10. Intuitive theories of information: beliefs about the value of redundancy.

    Science.gov (United States)

    Soll, J B

    1999-03-01

    In many situations, quantity estimates from multiple experts or diagnostic instruments must be collected and combined. Normatively, and all else equal, one should value information sources that are nonredundant, in the sense that correlation in forecast errors should be minimized. Past research on the preference for redundancy has been inconclusive. While some studies have suggested that people correctly place higher value on uncorrelated inputs when collecting estimates, others have shown that people either ignore correlation or, in some cases, even prefer it. The present experiments show that the preference for redundancy depends on one's intuitive theory of information. The most common intuitive theory identified is the Error Tradeoff Model (ETM), which explicitly distinguishes between measurement error and bias. According to ETM, measurement error can only be averaged out by consulting the same source multiple times (normatively false), and bias can only be averaged out by consulting different sources (normatively true). As a result, ETM leads people to prefer redundant estimates when the ratio of measurement error to bias is relatively high. Other participants favored different theories. Some adopted the normative model, while others were reluctant to mathematically average estimates from different sources in any circumstance. In a post hoc analysis, science majors were more likely than others to subscribe to the normative model. While tentative, this result lends insight into how intuitive theories might develop and also has potential ramifications for how statistical concepts such as correlation might best be learned and internalized. Copyright 1999 Academic Press.

  11. Performance of hybrid-ARQ with incremental redundancy over relay channels

    KAUST Repository

    Chelli, Ali; Alouini, Mohamed-Slim

    2012-01-01

    In this paper, we consider a relay network consisting of a source, a relay, and a destination. The source transmits a message to the destination using hybrid automatic repeat request (HARQ) with incremental redundancy (IR). The relay overhears

  12. Reliability analysis of a complex standby redundant systems

    International Nuclear Information System (INIS)

    Subramanian, R.; Anantharaman, V.

    1995-01-01

    In any redundant system, the state of the standby unit is usually taken to be hot, warm or cold. In this paper, we present a new model of a two unit standby system wherein the standby unit is put in cold state for a certain amount of time before it is allowed to become warm. Upon failure of the online unit, the standby unit, if in warm state, instantaneously starts operating online; if it is in cold state, an emergency switching is made which takes it to warm state (and hence online) either instantaneously or non-instantaneously--each with some probability; if it is under repair, the system breaks down. Assuming all the associated distributions to be general except that of the life time of the standby unit in the warm state, various reliability characteristics that are of interest to reliability engineers and system designers are derived. A comprehensive cost function is also constructed and is then optimized with respect to three different control parameters numerically. In addition numerical results are presented to illustrate the behaviour of the various reliability characteristics derived

  13. Sexual selection, redundancy and survival of the most beautiful

    Indian Academy of Sciences (India)

    A model is described of a highly redundant complex organism that has overlapping banks of genes such that each vital function is specified by several different genetic systems. This generates a synergistic profile linking probability of survival to the number of deleterious mutations in the genome. Computer models show ...

  14. FAULT DIAGNOSIS OF AN AIRCRAFT CONTROL SURFACES WITH AN AUTOMATED CONTROL SYSTEM

    Directory of Open Access Journals (Sweden)

    Blessing D. Ogunvoul

    2017-01-01

    Full Text Available This article is devoted to studying of fault diagnosis of an aircraft control surfaces using fault models to identify specific causes. Such failures as jamming, vibration, extreme run out and performance decrease are covered.It is proved that in case of an actuator failure or flight control structural damage, the aircraft performance decreases significantly. Commercial aircraft frequently appear in the areas of military conflicts and terrorist activity, where the risk of shooting attack is high, for example in Syria, Iraq, South Sudan etc. Accordingly, it is necessary to create and assess the fault model to identify the flight control failures.The research results demonstrate that the adequate fault model is the first step towards the managing the challenges of loss of aircraft controllability. This model is also an element of adaptive failure-resistant management model.The research considers the relationship between the parameters of an i th state of a control surface and its angular rate, also parameters classification associated with specific control surfaces in order to avoid conflict/inconsistency in the determination of a faulty control surface and its condition.The results of the method obtained in this article can be used in the design of an aircraft automated control system for timely identification of fault/failure of a specific control surface, that would contribute to an effective role aimed at increasing the survivability of an aircraft and increasing the acceptable level of safety due to loss of control.

  15. Sharing the cost of redundant items

    DEFF Research Database (Denmark)

    Hougaard, Jens Leth; Moulin, Hervé

    2014-01-01

    We ask how to share the cost of finitely many public goods (items) among users with different needs: some smaller subsets of items are enough to serve the needs of each user, yet the cost of all items must be covered, even if this entails inefficiently paying for redundant items. Typical examples...... are network connectivity problems when an existing (possibly inefficient) network must be maintained. We axiomatize a family cost ratios based on simple liability indices, one for each agent and for each item, measuring the relative worth of this item across agents, and generating cost allocation rules...... additive in costs....

  16. Redundancy proves its worth in FR Germany [emergency power supplies

    International Nuclear Information System (INIS)

    Simon, M.

    1987-01-01

    An analysis of loss of power events at nuclear power stations in FR Germany has confirmed the data used in the German risk study and underlined the advantages of providing a high degree of redundancy in emergency power supplies. (author)

  17. Knowledge sharing in construction partnering projects - redundancy, boundary objects and brokers

    DEFF Research Database (Denmark)

    Koch, Christian; Thuesen, Christian

    2013-01-01

    is on two dialogue excerpts, one on process, and one on product knowledge exchanges. The diversity and disjunctive feature of the practices form a condition of possibility for knowledge handling and synthesis into the built construct. Relation-based interaction is necessary with boundary objects and brokers......This article adopts practice-based theory for understanding inter-organisational knowledge work and extends it with a discussion of the role of redundancy. In this view, a constellation of firms is a multiple configuration of communities of practices, characterised by overlapping practises......, multiple memberships and different levels of participation, and accompanied by a governance frame. The paper discusses central mechanisms for coordinating knowledge in such a complex construction project. The knowledge relations are conceptualised through focusing on redundancy, understood as negotiated...

  18. Redundant sensor validation by using fuzzy logic

    International Nuclear Information System (INIS)

    Holbert, K.E.; Heger, A.S.; Alang-Rashid, N.K.

    1994-01-01

    This research is motivated by the need to relax the strict boundary of numeric-based signal validation. To this end, the use of fuzzy logic for redundant sensor validation is introduced. Since signal validation employs both numbers and qualitative statements, fuzzy logic provides a pathway for transforming human abstractions into the numerical domain and thus coupling both sources of information. With this transformation, linguistically expressed analysis principles can be coded into a classification rule-base for signal failure detection and identification

  19. Simulator of a fail detector system for redundant sensors

    International Nuclear Information System (INIS)

    Assumpcao Filho, E.O.; Nakata, H.

    1990-01-01

    A failure detection and isolation system (FDI) simulation program has been developed for IBM-PC microcomputers. The program, based on the sequencial likelihood ratio testing method developed by A. Wald, was implemented with Monte-Carlo technique. The calculated failure detection rate was favorably compared against the wind-tunnel experimental redundant temperature sensors. (author)

  20. Control of grinding polygonal surfaces

    Directory of Open Access Journals (Sweden)

    Юрій Володимирович Петраков

    2017-12-01

    Full Text Available Grinding of non-round surfaces, in particular polygonal surfaces of dies, is characterized by substantial non stationary. At different sections of the profile, the change in the main characteristic (Material Removal Rate – MRR process reaches tens of times. To stabilize the grinding process, it is recommended to control the spindle speed of the workpiece CNC grinding machine. Created software that allows to design the control program on the basis of mathematical model of the system. The determination of MRR is realized automatically in the simulation of the grinding process which uses the algorithm developed for solving problems in geometric interaction of the workpiece and the wheel. In forming the control program is possible takes into account the limitations on the maximum circumferential force of cutting, and the maximum allowable acceleration of the machine spindle. Practice has shown that full stabilization is not obtained, even though the performance is increased more than 2 times, while ensuring the quality of the surface. The developed block diagram of the grinding process can serve as a basis for further improvement in the solution of dynamic problems.

  1. Interactions between facial emotion and identity in face processing: evidence based on redundancy gains.

    Science.gov (United States)

    Yankouskaya, Alla; Booth, David A; Humphreys, Glyn

    2012-11-01

    Interactions between the processing of emotion expression and form-based information from faces (facial identity) were investigated using the redundant-target paradigm, in which we specifically tested whether identity and emotional expression are integrated in a superadditive manner (Miller, Cognitive Psychology 14:247-279, 1982). In Experiments 1 and 2, participants performed emotion and face identity judgments on faces with sad or angry emotional expressions. Responses to redundant targets were faster than responses to either single target when a universal emotion was conveyed, and performance violated the predictions from a model assuming independent processing of emotion and face identity. Experiment 4 showed that these effects were not modulated by varying interstimulus and nontarget contingencies, and Experiment 5 demonstrated that the redundancy gains were eliminated when faces were inverted. Taken together, these results suggest that the identification of emotion and facial identity interact in face processing.

  2. Electronic logic to enhance switch reliability in detecting openings and closures of redundant switches

    Science.gov (United States)

    Cooper, James A.

    1986-01-01

    A logic circuit is used to enhance redundant switch reliability. Two or more switches are monitored for logical high or low output. The output for the logic circuit produces a redundant and failsafe representation of the switch outputs. When both switch outputs are high, the output is high. Similarly, when both switch outputs are low, the logic circuit's output is low. When the output states of the two switches do not agree, the circuit resolves the conflict by memorizing the last output state which both switches were simultaneously in and produces the logical complement of this output state. Thus, the logic circuit of the present invention allows the redundant switches to be treated as if they were in parallel when the switches are open and as if they were in series when the switches are closed. A failsafe system having maximum reliability is thereby produced.

  3. The redundant target effect is affected by modality switch costs

    DEFF Research Database (Denmark)

    Gondan, Matthias; Lange, K.; Rösler, F.

    2004-01-01

    When participants have to respond to stimuli of two modalities, faster reaction times are observed for simultaneous, bimodal events than for unimodal events (the redundant target effect [RTE]). This finding has been interpreted as reflecting processing gains for bimodal relative to unimodal stimu...

  4. Redundant and physical black hole parameters: Is there an independent physical dilaton charge?

    Energy Technology Data Exchange (ETDEWEB)

    Hajian, K., E-mail: kamalhajian@ipm.ir; Sheikh-Jabbari, M.M., E-mail: jabbari@theory.ipm.ac.ir

    2017-05-10

    Black holes as solutions to gravity theories, are generically identified by a set of parameters. Some of these parameters are associated with black hole physical conserved charges, like ADM charges. There can also be some “redundant parameters.” We propose necessary conditions for a parameter to be physical. The conditions are essentially integrability and non-triviality of the charge variations arising from “parametric variations,” variation of the solution with respect to the chosen parameters. In addition, we prove that variation of the redundant parameters which do not meet our criteria do not appear in the first law of thermodynamics. As an interesting application, we show that dilaton moduli are redundant parameters for black hole solutions to Einstein–Maxwell–(Axion)–Dilaton theories, because variations in dilaton moduli would render entropy, mass, electric charges or angular momenta non-integrable. Our results are in contrast with modification of the first law due to scalar charges suggested in Gibbons–Kallosh–Kol paper and its follow-ups. We also briefly discuss implications of our results for the attractor behavior of extremal black holes.

  5. Optimal Control Surface Layout for an Aeroservoelastic Wingbox

    Science.gov (United States)

    Stanford, Bret K.

    2017-01-01

    This paper demonstrates a technique for locating the optimal control surface layout of an aeroservoelastic Common Research Model wingbox, in the context of maneuver load alleviation and active utter suppression. The combinatorial actuator layout design is solved using ideas borrowed from topology optimization, where the effectiveness of a given control surface is tied to a layout design variable, which varies from zero (the actuator is removed) to one (the actuator is retained). These layout design variables are optimized concurrently with a large number of structural wingbox sizing variables and control surface actuation variables, in order to minimize the sum of structural weight and actuator weight. Results are presented that demonstrate interdependencies between structural sizing patterns and optimal control surface layouts, for both static and dynamic aeroelastic physics.

  6. The restricted isometry property meets nonlinear approximation with redundant frames

    DEFF Research Database (Denmark)

    Gribonval, Rémi; Nielsen, Morten

    2013-01-01

    with a redundant frame. The main ingredients of our approach are: a) Jackson and Bernstein inequalities, associated to the characterization of certain approximation spaces with interpolation spaces; b) a proof that for overcomplete frames which satisfy a Bernstein inequality, these interpolation spaces are nothing...

  7. 75 FR 65238 - Loan Guaranty: Elimination of Redundant Regulations; Correction

    Science.gov (United States)

    2010-10-22

    ... DEPARTMENT OF VETERANS AFFAIRS 38 CFR Part 36 RIN 2900-AN71 Loan Guaranty: Elimination of... June 15, 2010 (75 FR 33704), amending its loan guaranty regulations to eliminate redundant regulations... INFORMATION CONTACT: William White, Acting Assistant Director for Loan Processing and Valuation (262...

  8. Quantum Darwinism in an Everyday Environment: Huge Redundancy in Scattered Photons

    Science.gov (United States)

    Riedel, Charles; Zurek, Wojciech

    2011-03-01

    We study quantum Darwinism---the redundant recording of information about the preferred states of a decohering system by its environment---for an object illuminated by a blackbody. In the cases of point-source, small disk, and isotropic illumination, we calculate the quantum mutual information between the object and its photon environment. We demonstrate that this realistic model exhibits fast and extensive proliferation of information about the object into the environment and results in redundancies orders of magnitude larger than the exactly soluble models considered to date. We also demonstrate a reduced ability to create records as initial environmental mixedness increases, in agreement with previous studies. This research is supported by the U.S. Department of Energy through the LANL/LDRD program and, in part, by the Foundational Questions Institute (FQXi).

  9. Optimal design of a system containing mixed redundancies with respect to reliability and cost

    International Nuclear Information System (INIS)

    Misra, K.B.

    1975-01-01

    A nuclear system generally consists of subsystems that may employ any of the partial, standby, and active redundancies, and is, therefore, a system with mixed type of redundancies. Optimization of reliability or availability of such systems at the design stage is a difficult problem. There appears to be no published work on the optimal design of maintained systems consisting of mixed redundancies. An attempt is therefore made, to present the basis of design and the solution technique to achieve this. An algorithm is described which makes the solution of this mathematically difficult problem possible. Some examples are demonstrated. To achieve further efficiency a study was organized and the recommendations for obtaining a minimum solution time are provided. Although, in the illustration, only the linear constraints and reliability, as the only design parameter, have been considered, the algorithm works well with the nonlinear type of constraints and can be used with other design parameters also. (author)

  10. Tomographical properties of uniformly redundant arrays

    International Nuclear Information System (INIS)

    Cannon, T.M.; Fenimore, E.E.

    1978-01-01

    Recent work in coded aperture imaging has shown that the uniformly redundant array (URA) can image distant planar radioactive sources with no artifacts. The performance of two URA apertures when used in a close-up tomographic imaging system is investigated. It is shown that a URA based on m sequences is superior to one based on quadratic residues. The m sequence array not only produces less obnoxious artifacts in tomographic imaging, but is also more resilient to some described detrimental effects of close-up imaging. It is shown that in spite of these close-up effects, tomographic depth resolution increases as the source is moved closer to the detector

  11. Development of a super-redundant multijoint manipulator for maintenance of nuclear reactors

    International Nuclear Information System (INIS)

    Ma, Shugen; Hirose, Shigeo.

    1994-01-01

    A tendon-driven manipulator, the CT Arm, has a specific tendon traction transmission mechanism, in which a pair of tendons for driving a joint is pulled from base actuators via pulleys mounted on the based-side joints. The mechanism makes the most of the coupled drive function of the tendon tractions and thus enables the lightweight manipulator to exhibit enormous payload capability. By this tendon-driven mechanism, a multijoint manipulator with super-redundant degrees of freedom could be realized, which is suitable to the maintenance of nuclear reactors. In this article, we introduce the CT Arm and discuss the possibility to generate a multijoint maintenance manipulator which has a super-redundant degrees of freedom. (author)

  12. Obstacle avoidance for kinematically redundant robots using an adaptive fuzzy logic algorithm

    International Nuclear Information System (INIS)

    Beheshti, M.T.H.; Tehrani, A.K.

    1999-05-01

    In this paper the Adaptive Fuzzy Logic approach for solving the inverse kinematics of redundant robots in an environment with obstacles is presented. The obstacles are modeled as convex bodies. A fuzzy rule base that is updated via an adaptive law is used to solve the inverse kinematic problem. Additional rules have been introduced to take care of the obstacles avoidance problem. The proposed method has advantages such as high accuracy, simplicity of computations and generality for all redundant robots. Simulation results illustrate much better tracking performance than the dynamic base solution for a given trajectory in cartesian space, while guaranteeing a collision-free trajectory and observation of a mechanical joint limit

  13. Surface-Controlled Metal Oxide Resistive Memory

    KAUST Repository

    Ke, Jr-Jian

    2015-10-28

    To explore the surface effect on resistive random-access memory (ReRAM), the impact of surface roughness on the characteristics of ZnO ReRAM were studied. The thickness-independent resistance and the higher switching probability of ZnO ReRAM with rough surfaces indicate the importance of surface oxygen chemisorption on the switching process. Furthermore, the improvements in switching probability, switching voltage and resistance distribution observed for ReRAM with rough surfaces can be attributed to the stable oxygen adatoms under various ambience conditions. The findings validate the surface-controlled stability and uniformity of ReRAM and can serve as the guideline for developing practical device applications.

  14. Derivation of three closed loop kinematic velocity models using normalized quaternion feedback for an autonomous redundant manipulator with application to inverse kinematics

    Energy Technology Data Exchange (ETDEWEB)

    Unseren, M.A.

    1993-04-01

    The report discusses the orientation tracking control problem for a kinematically redundant, autonomous manipulator moving in a three dimensional workspace. The orientation error is derived using the normalized quaternion error method of Ickes, the Luh, Walker, and Paul error method, and a method suggested here utilizing the Rodrigues parameters, all of which are expressed in terms of normalized quaternions. The analytical time derivatives of the orientation errors are determined. The latter, along with the translational velocity error, form a dosed loop kinematic velocity model of the manipulator using normalized quaternion and translational position feedback. An analysis of the singularities associated with expressing the models in a form suitable for solving the inverse kinematics problem is given. Two redundancy resolution algorithms originally developed using an open loop kinematic velocity model of the manipulator are extended to properly take into account the orientation tracking control problem. This report furnishes the necessary mathematical framework required prior to experimental implementation of the orientation tracking control schemes on the seven axis CESARm research manipulator or on the seven-axis Robotics Research K1207i dexterous manipulator, the latter of which is to be delivered to the Oak Ridge National Laboratory in 1993.

  15. Derivation of three closed loop kinematic velocity models using normalized quaternion feedback for an autonomous redundant manipulator with application to inverse kinematics

    International Nuclear Information System (INIS)

    Unseren, M.A.

    1993-04-01

    The report discusses the orientation tracking control problem for a kinematically redundant, autonomous manipulator moving in a three dimensional workspace. The orientation error is derived using the normalized quaternion error method of Ickes, the Luh, Walker, and Paul error method, and a method suggested here utilizing the Rodrigues parameters, all of which are expressed in terms of normalized quaternions. The analytical time derivatives of the orientation errors are determined. The latter, along with the translational velocity error, form a dosed loop kinematic velocity model of the manipulator using normalized quaternion and translational position feedback. An analysis of the singularities associated with expressing the models in a form suitable for solving the inverse kinematics problem is given. Two redundancy resolution algorithms originally developed using an open loop kinematic velocity model of the manipulator are extended to properly take into account the orientation tracking control problem. This report furnishes the necessary mathematical framework required prior to experimental implementation of the orientation tracking control schemes on the seven axis CESARm research manipulator or on the seven-axis Robotics Research K1207i dexterous manipulator, the latter of which is to be delivered to the Oak Ridge National Laboratory in 1993

  16. Functional diversity and redundancy across fish gut, sediment and water bacterial communities.

    Science.gov (United States)

    Escalas, Arthur; Troussellier, Marc; Yuan, Tong; Bouvier, Thierry; Bouvier, Corinne; Mouchet, Maud A; Flores Hernandez, Domingo; Ramos Miranda, Julia; Zhou, Jizhong; Mouillot, David

    2017-08-01

    This article explores the functional diversity and redundancy in a bacterial metacommunity constituted of three habitats (sediment, water column and fish gut) in a coastal lagoon under anthropogenic pressure. Comprehensive functional gene arrays covering a wide range of ecological processes and stress resistance genes to estimate the functional potential of bacterial communities were used. Then, diversity partitioning was used to characterize functional diversity and redundancy within (α), between (β) and across (γ) habitats. It was showed that all local communities exhibit a highly diversified potential for the realization of key ecological processes and resistance to various environmental conditions, supporting the growing evidence that macro-organisms microbiomes harbour a high functional potential and are integral components of functional gene dynamics in aquatic bacterial metacommunities. Several levels of functional redundancy at different scales of the bacterial metacommunity were observed (within local communities, within habitats and at the metacommunity level). The results suggested a high potential for the realization of spatial ecological insurance within this ecosystem, that is, the functional compensation among microorganisms for the realization and maintenance of key ecological processes, within and across habitats. Finally, the role of macro-organisms as dispersal vectors of microbes and their potential influence on marine metacommunity dynamics were discussed. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

  17. Switching algorithm for maglev train double-modular redundant positioning sensors.

    Science.gov (United States)

    He, Ning; Long, Zhiqiang; Xue, Song

    2012-01-01

    High-resolution positioning for maglev trains is implemented by detecting the tooth-slot structure of the long stator installed along the rail, but there are large joint gaps between long stator sections. When a positioning sensor is below a large joint gap, its positioning signal is invalidated, thus double-modular redundant positioning sensors are introduced into the system. This paper studies switching algorithms for these redundant positioning sensors. At first, adaptive prediction is applied to the sensor signals. The prediction errors are used to trigger sensor switching. In order to enhance the reliability of the switching algorithm, wavelet analysis is introduced to suppress measuring disturbances without weakening the signal characteristics reflecting the stator joint gap based on the correlation between the wavelet coefficients of adjacent scales. The time delay characteristics of the method are analyzed to guide the algorithm simplification. Finally, the effectiveness of the simplified switching algorithm is verified through experiments.

  18. Information theory and artificial grammar learning: inferring grammaticality from redundancy.

    Science.gov (United States)

    Jamieson, Randall K; Nevzorova, Uliana; Lee, Graham; Mewhort, D J K

    2016-03-01

    In artificial grammar learning experiments, participants study strings of letters constructed using a grammar and then sort novel grammatical test exemplars from novel ungrammatical ones. The ability to distinguish grammatical from ungrammatical strings is often taken as evidence that the participants have induced the rules of the grammar. We show that judgements of grammaticality are predicted by the local redundancy of the test strings, not by grammaticality itself. The prediction holds in a transfer test in which test strings involve different letters than the training strings. Local redundancy is usually confounded with grammaticality in stimuli widely used in the literature. The confounding explains why the ability to distinguish grammatical from ungrammatical strings has popularized the idea that participants have induced the rules of the grammar, when they have not. We discuss the judgement of grammaticality task in terms of attribute substitution and pattern goodness. When asked to judge grammaticality (an inaccessible attribute), participants answer an easier question about pattern goodness (an accessible attribute).

  19. Switching Algorithm for Maglev Train Double-Modular Redundant Positioning Sensors

    Directory of Open Access Journals (Sweden)

    Song Xue

    2012-08-01

    Full Text Available High-resolution positioning for maglev trains is implemented by detecting the tooth-slot structure of the long stator installed along the rail, but there are large joint gaps between long stator sections. When a positioning sensor is below a large joint gap, its positioning signal is invalidated, thus double-modular redundant positioning sensors are introduced into the system. This paper studies switching algorithms for these redundant positioning sensors. At first, adaptive prediction is applied to the sensor signals. The prediction errors are used to trigger sensor switching. In order to enhance the reliability of the switching algorithm, wavelet analysis is introduced to suppress measuring disturbances without weakening the signal characteristics reflecting the stator joint gap based on the correlation between the wavelet coefficients of adjacent scales. The time delay characteristics of the method are analyzed to guide the algorithm simplification. Finally, the effectiveness of the simplified switching algorithm is verified through experiments.

  20. Estimation of component redundancy in optimal age maintenance

    OpenAIRE

    Siopa, Jorge; Garção, José; Silva, Júlio

    2012-01-01

    The classical Optimal Age-Replacement defines the maintenance strategy based on the equipment failure consequences. For severe consequences an early equipment replacement is recommended. For minor consequences the repair after failure is proposed. One way of reducing the failure consequences is the use of redundancies, especially if the equipment failure rate is decreasing over time, since in this case the preventive replacement does not reduce the risk of failure. The estimation of an ac...

  1. Designing Broadband Access Networks with Triple Redundancy

    DEFF Research Database (Denmark)

    Pedersen, Jens Myrup; Riaz, Muhammad Tahir; Knudsen, Thomas Phillip

    2005-01-01

    An architecture is proposed for designing broadband access networks, which offer triple redundancy to the end users, resulting in networks providing connectivity even in case of any two independent node or line failures. Two physically independent connections are offered by fiber, and the last...... provided by some wireless solution. Based on experience with planning Fiber To The Home, the architecture is designed to meet a number of demands, making it practicable and useful in realworld network planning. The proposed wired topology is planar, and suitable for being fitted onto the road network...

  2. Inhibition and Language Pragmatic View in Redundant Data Problem Solving

    Science.gov (United States)

    Setti, Annalisa; Caramelli, Nicoletta

    2007-01-01

    The present study concerns redundant data problems, defined as problems in which irrelevant data is provided. This type of problem provides a misleading context [Pascual-Leone, J. (1987). Organismic process for neo-Piagetian theories: A dialectical causal account of cognitive development. "International Journal of Psychology," 22, 531-570] similar…

  3. Fps/Fes and Fer protein-tyrosinekinases play redundant roles in regulating hematopoiesis.

    Science.gov (United States)

    Senis, Yotis A; Craig, Andrew W B; Greer, Peter A

    2003-08-01

    The highly related protein-tyrosine kinases Fps (also called Fes) and Fer are sole members of a subfamily of kinases. In this study, knock-in mice harboring kinase-inactivating mutations in both fps and fer alleles were used to assess functional redundancy between Fps and Fer kinases in regulating hematopoiesis. Mice harboring kinase-inactivating mutations in fps and fer alleles were generated previously. Compound homozygous mice were bred that lack both Fps and Fer kinase activities and progeny were analyzed for potential defects in viability and fertility. Potential differences in hematopoiesis were analyzed by lineage analysis of bone marrow cells, peripheral blood counts, and hematopoietic progenitor cell colony-forming assays. Mice devoid of both Fps and Fer kinase activities were viable and displayed reduced fertility. Circulating levels of neutrophils, erythrocytes, and platelets were elevated in compound mutant mice compared to wild-type controls, suggesting that hematopoiesis is deregulated in the absence of Fps and Fer kinases. Compound mutant mice also showed reduced overall bone marrow cellularity, and lineage analysis revealed elevated CD11b(hi)Ly-6G(lo) myeloid cells, which may reflect increased granulocyte progenitors. Although no differences in the overall number of granulocyte/monocyte colony-forming progenitors were observed, qualitative differences in myeloid colonies from compound mutant mice suggested a role for Fps and Fer kinases in regulating cell-cell adhesion or a skewing in cellularity of colonies. Mice lacking both Fps and Fer kinase activities develop normally, show reduced fertility, and display defects in hematopoiesis, thus providing evidence for functional redundancy between Fps and Fer kinases in regulating hematopoiesis.

  4. Utilizing Nested Normal Form to Design Redundancy Free JSON Schemas

    Directory of Open Access Journals (Sweden)

    Wai Yin Mok

    2016-12-01

    Full Text Available JSON (JavaScript Object Notation is a lightweight data-interchange format for the Internet. JSON is built on two structures: (1 a collection of name/value pairs and (2 an ordered list of values (http://www.json.org/. Because of this simple approach, JSON is easy to use and it has the potential to be the data interchange format of choice for the Internet. Similar to XML, JSON schemas allow nested structures to model hierarchical data. As data interchange over the Internet increases exponentially due to cloud computing or otherwise, redundancy free JSON data are an attractive form of communication because they improve the quality of data communication through eliminating update anomaly. Nested Normal Form, a normal form for hierarchical data, is a precise characterization of redundancy. A nested table, or a hierarchical schema, is in Nested Normal Form if and only if it is free of redundancy caused by multivalued and functional dependencies. Using Nested Normal Form as a guide, this paper introduces a JSON schema design methodology that begins with UML use case diagrams, communication diagrams and class diagrams that model a system under study. Based on the use cases’ execution frequencies and the data passed between involved parties in the communication diagrams, the proposed methodology selects classes from the class diagrams to be the roots of JSON scheme trees and repeatedly adds classes from the class diagram to the scheme trees as long as the schemas satisfy Nested Normal Form. This process continues until all of the classes in the class diagram have been added to some JSON scheme trees.

  5. On the optimal scheduling of periodic tests and maintenance for reliable redundant components

    International Nuclear Information System (INIS)

    Courtois, Pierre-Jacques; Delsarte, Philippe

    2006-01-01

    Periodically, some m of the n redundant components of a dependable system may have to be taken out of service for inspection, testing or preventive maintenance. The system is then constrained to operate with lower (n-m) redundancy and thus with less reliability during these periods. However, more frequent periodic inspections decrease the probability that a component fail undetected in the time interval between successive inspections. An optimal time schedule of periodic preventive operations arises from these two conflicting factors, balancing the loss of redundancy during inspections against the reliability benefits of more frequent inspections. Considering no other factor than this decreased redundancy at inspection time, this paper demonstrates the existence of an optimal interval between inspections, which maximizes the mean time between system failures. By suitable transformations and variable identifications, an analytic closed form expression of the optimum is obtained for the general (m, n) case. The optimum is shown to be unique within the ranges of parameter values valid in practice; its expression is easy to evaluate and shown to be useful to analyze and understand the influence of these parameters. Inspections are assumed to be perfect, i.e. they cause no component failure by themselves and leave no failure undetected. In this sense, the optimum determines a lowest bound for the system failure rate that can be achieved by a system of n-redundant components, m of which require for inspection or maintenance recurrent periods of unavailability of length t. The model and its general closed form solution are believed to be new . Previous work had computed optimal values for an estimation of a time average of system unavailability, but by numerical procedures only and with different numerical approximations, other objectives and model assumptions (one component only inspected at a time), and taking into account failures caused by testing itself, repair and

  6. A Simple Example of ``Quantum Darwinism'': Redundant Information Storage in Many-Spin Environments

    Science.gov (United States)

    Blume-Kohout, Robin; Zurek, Wojciech H.

    2005-11-01

    As quantum information science approaches the goal of constructing quantum computers, understanding loss of information through decoherence becomes increasingly important. The information about a system that can be obtained from its environment can facilitate quantum control and error correction. Moreover, observers gain most of their information indirectly, by monitoring (primarily photon) environments of the "objects of interest." Exactly how this information is inscribed in the environment is essential for the emergence of "the classical" from the quantum substrate. In this paper, we examine how many-qubit (or many-spin) environments can store information about a single system. The information lost to the environment can be stored redundantly, or it can be encoded in entangled modes of the environment. We go on to show that randomly chosen states of the environment almost always encode the information so that an observer must capture a majority of the environment to deduce the system's state. Conversely, in the states produced by a typical decoherence process, information about a particular observable of the system is stored redundantly. This selective proliferation of "the fittest information" (known as Quantum Darwinism) plays a key role in choosing the preferred, effectively classical observables of macroscopic systems. The developing appreciation that the environment functions not just as a garbage dump, but as a communication channel, is extending our understanding of the environment's role in the quantum-classical transition beyond the traditional paradigm of decoherence.

  7. Redundant and physical black hole parameters: Is there an independent physical dilaton charge?

    Directory of Open Access Journals (Sweden)

    K. Hajian

    2017-05-01

    Full Text Available Black holes as solutions to gravity theories, are generically identified by a set of parameters. Some of these parameters are associated with black hole physical conserved charges, like ADM charges. There can also be some “redundant parameters.” We propose necessary conditions for a parameter to be physical. The conditions are essentially integrability and non-triviality of the charge variations arising from “parametric variations,” variation of the solution with respect to the chosen parameters. In addition, we prove that variation of the redundant parameters which do not meet our criteria do not appear in the first law of thermodynamics. As an interesting application, we show that dilaton moduli are redundant parameters for black hole solutions to Einstein–Maxwell–(Axion–Dilaton theories, because variations in dilaton moduli would render entropy, mass, electric charges or angular momenta non-integrable. Our results are in contrast with modification of the first law due to scalar charges suggested in Gibbons–Kallosh–Kol paper [1] and its follow-ups. We also briefly discuss implications of our results for the attractor behavior of extremal black holes.

  8. Balanced and servo control surfaces

    Science.gov (United States)

    1930-01-01

    Many reports on various control systems are available, but the results cannot be generally applied since the effect of particular changes of surface-form and mounting are subject to variations depending upon airfoil section and influences of airplane layout. This report presents a simple analysis of several control systems in more general use. Elevators, ailerons, and rudders are all discussed.

  9. Modified parity space averaging approaches for online cross-calibration of redundant sensors in nuclear reactors

    Directory of Open Access Journals (Sweden)

    Moath Kassim

    2018-05-01

    Full Text Available To maintain safety and reliability of reactors, redundant sensors are usually used to measure critical variables and estimate their averaged time-dependency. Nonhealthy sensors can badly influence the estimation result of the process variable. Since online condition monitoring was introduced, the online cross-calibration method has been widely used to detect any anomaly of sensor readings among the redundant group. The cross-calibration method has four main averaging techniques: simple averaging, band averaging, weighted averaging, and parity space averaging (PSA. PSA is used to weigh redundant signals based on their error bounds and their band consistency. Using the consistency weighting factor (C, PSA assigns more weight to consistent signals that have shared bands, based on how many bands they share, and gives inconsistent signals of very low weight. In this article, three approaches are introduced for improving the PSA technique: the first is to add another consistency factor, so called trend consistency (TC, to include a consideration of the preserving of any characteristic edge that reflects the behavior of equipment/component measured by the process parameter; the second approach proposes replacing the error bound/accuracy based weighting factor (Wa with a weighting factor based on the Euclidean distance (Wd, and the third approach proposes applying Wd,TC,andC, all together. Cold neutron source data sets of four redundant hydrogen pressure transmitters from a research reactor were used to perform the validation and verification. Results showed that the second and third modified approaches lead to reasonable improvement of the PSA technique. All approaches implemented in this study were similar in that they have the capability to (1 identify and isolate a drifted sensor that should undergo calibration, (2 identify a faulty sensor/s due to long and continuous missing data range, and (3 identify a healthy sensor. Keywords: Nuclear Reactors

  10. Links between N-modular redundancy and the theory of error-correcting codes

    Science.gov (United States)

    Bobin, V.; Whitaker, S.; Maki, G.

    1992-01-01

    N-Modular Redundancy (NMR) is one of the best known fault tolerance techniques. Replication of a module to achieve fault tolerance is in some ways analogous to the use of a repetition code where an information symbol is replicated as parity symbols in a codeword. Linear Error-Correcting Codes (ECC) use linear combinations of information symbols as parity symbols which are used to generate syndromes for error patterns. These observations indicate links between the theory of ECC and the use of hardware redundancy for fault tolerance. In this paper, we explore some of these links and show examples of NMR systems where identification of good and failed elements is accomplished in a manner similar to error correction using linear ECC's.

  11. Fuzzy Mutual Information Based min-Redundancy and Max-Relevance Heterogeneous Feature Selection

    Directory of Open Access Journals (Sweden)

    Daren Yu

    2011-08-01

    Full Text Available Feature selection is an important preprocessing step in pattern classification and machine learning, and mutual information is widely used to measure relevance between features and decision. However, it is difficult to directly calculate relevance between continuous or fuzzy features using mutual information. In this paper we introduce the fuzzy information entropy and fuzzy mutual information for computing relevance between numerical or fuzzy features and decision. The relationship between fuzzy information entropy and differential entropy is also discussed. Moreover, we combine fuzzy mutual information with qmin-Redundancy-Max-Relevanceq, qMax-Dependencyq and min-Redundancy-Max-Dependencyq algorithms. The performance and stability of the proposed algorithms are tested on benchmark data sets. Experimental results show the proposed algorithms are effective and stable.

  12. Statistical Redundancy Testing for Improved Gene Selection in Cancer Classification Using Microarray Data

    Directory of Open Access Journals (Sweden)

    J. Sunil Rao

    2007-01-01

    Full Text Available In gene selection for cancer classifi cation using microarray data, we define an eigenvalue-ratio statistic to measure a gene’s contribution to the joint discriminability when this gene is included into a set of genes. Based on this eigenvalueratio statistic, we define a novel hypothesis testing for gene statistical redundancy and propose two gene selection methods. Simulation studies illustrate the agreement between statistical redundancy testing and gene selection methods. Real data examples show the proposed gene selection methods can select a compact gene subset which can not only be used to build high quality cancer classifiers but also show biological relevance.

  13. Redundancy Effect on Retention of Vocabulary Words Using Multimedia Presentation

    Science.gov (United States)

    Samur, Yavuz

    2012-01-01

    This study was designed to examine the effect of the redundancy principle in a multimedia presentation constructed for foreign language vocabulary learning on undergraduate students' retention. The underlying hypothesis of this study is that when the students are exposed to the material in multiple ways through animation, concurrent narration,…

  14. Systematic Luby Transform codes as incremental redundancy scheme

    CSIR Research Space (South Africa)

    Grobler, TL

    2011-09-01

    Full Text Available Transform Codes as Incremental Redundancy Scheme T. L. Grobler y, E. R. Ackermann y, J. C. Olivier y and A. J. van Zylz Department of Electrical, Electronic and Computer Engineering University of Pretoria, Pretoria 0002, South Africa Email: trienkog...@gmail.com, etienne.ackermann@ieee.org yDefence, Peace, Safety and Security (DPSS) Council for Scientific and Industrial Research (CSIR), Pretoria 0001, South Africa zDepartment of Mathematics and Applied Mathematics University of Pretoria, Pretoria 0002, South...

  15. A New Biobjective Model to Optimize Integrated Redundancy Allocation and Reliability-Centered Maintenance Problems in a System Using Metaheuristics

    Directory of Open Access Journals (Sweden)

    Shima MohammadZadeh Dogahe

    2015-01-01

    Full Text Available A novel integrated model is proposed to optimize the redundancy allocation problem (RAP and the reliability-centered maintenance (RCM simultaneously. A system of both repairable and nonrepairable components has been considered. In this system, electronic components are nonrepairable while mechanical components are mostly repairable. For nonrepairable components, a redundancy allocation problem is dealt with to determine optimal redundancy strategy and number of redundant components to be implemented in each subsystem. In addition, a maintenance scheduling problem is considered for repairable components in order to identify the best maintenance policy and optimize system reliability. Both active and cold standby redundancy strategies have been taken into account for electronic components. Also, net present value of the secondary cost including operational and maintenance costs has been calculated. The problem is formulated as a biobjective mathematical programming model aiming to reach a tradeoff between system reliability and cost. Three metaheuristic algorithms are employed to solve the proposed model: Nondominated Sorting Genetic Algorithm (NSGA-II, Multiobjective Particle Swarm Optimization (MOPSO, and Multiobjective Firefly Algorithm (MOFA. Several test problems are solved using the mentioned algorithms to test efficiency and effectiveness of the solution approaches and obtained results are analyzed.

  16. A model of primate visual cortex based on category-specific redundancies in natural images

    Science.gov (United States)

    Malmir, Mohsen; Shiry Ghidary, S.

    2010-12-01

    Neurophysiological and computational studies have proposed that properties of natural images have a prominent role in shaping selectivity of neurons in the visual cortex. An important property of natural images that has been studied extensively is the inherent redundancy in these images. In this paper, the concept of category-specific redundancies is introduced to describe the complex pattern of dependencies between responses of linear filters to natural images. It is proposed that structural similarities between images of different object categories result in dependencies between responses of linear filters in different spatial scales. It is also proposed that the brain gradually removes these dependencies in different areas of the ventral visual hierarchy to provide a more efficient representation of its sensory input. The authors proposed a model to remove these redundancies and trained it with a set of natural images using general learning rules that are developed to remove dependencies between responses of neighbouring neurons. Results of experiments demonstrate the close resemblance of neuronal selectivity between different layers of the model and their corresponding visual areas.

  17. A Multi-objective PMU Placement Method Considering Observability and Measurement Redundancy using ABC Algorithm

    Directory of Open Access Journals (Sweden)

    KULANTHAISAMY, A.

    2014-05-01

    Full Text Available This paper presents a Multi- objective Optimal Placement of Phasor Measurement Units (MOPP method in large electric transmission systems. It is proposed for minimizing the number of Phasor Measurement Units (PMUs for complete system observability and maximizing the measurement redundancy of the system, simultaneously. The measurement redundancy means that number of times a bus is able to monitor more than once by PMUs set. A higher level of measurement redundancy can maximize the total system observability and it is desirable for a reliable power system state estimation. Therefore, simultaneous optimization of the two conflicting objectives are performed using a binary coded Artificial Bee Colony (ABC algorithm. The complete observability of the power system is first prepared and then, single line loss contingency condition is considered to the main model. The efficiency of the proposed method is validated on IEEE 14, 30, 57 and 118 bus test systems. The valuable approach of ABC algorithm is demonstrated in finding the optimal number of PMUs and their locations by comparing the performance with earlier works.

  18. Toward an Integrated Design, Inspection and Redundancy Research Program.

    Science.gov (United States)

    1984-01-01

    William Creelman William H. Silcox National Marine Service Standard Oil Company of California St. Louis, Missouri San Francisco, California .-- N...develop physical models and generic tools for analyzing the effects of redundancy, reserve strength, and residual strength on the system behavior of marine...probabilistic analyses to be applicable to real-world problems, this program needs to provide - the deterministic physical models and generic tools upon

  19. Sustainable Modular Adaptive Redundancy Technique Emphasizing Partial Reconfiguration for Reduced Power Consumption

    Directory of Open Access Journals (Sweden)

    R. Al-Haddad

    2011-01-01

    Full Text Available As reconfigurable devices' capacities and the complexity of applications that use them increase, the need for self-reliance of deployed systems becomes increasingly prominent. Organic computing paradigms have been proposed for fault-tolerant systems because they promote behaviors that allow complex digital systems to adapt and survive in demanding environments. In this paper, we develop a sustainable modular adaptive redundancy technique (SMART composed of a two-layered organic system. The hardware layer is implemented on a Xilinx Virtex-4 Field Programmable Gate Array (FPGA to provide self-repair using a novel approach called reconfigurable adaptive redundancy system (RARS. The software layer supervises the organic activities on the FPGA and extends the self-healing capabilities through application-independent, intrinsic, and evolutionary repair techniques that leverage the benefits of dynamic partial reconfiguration (PR. SMART was evaluated using a Sobel edge-detection application and was shown to tolerate stressful sequences of injected transient and permanent faults while reducing dynamic power consumption by 30% compared to conventional triple modular redundancy (TMR techniques, with nominal impact on the fault-tolerance capabilities. Moreover, PR is employed to keep the system on line while under repair and also to reduce repair time. Experiments have shown a 27.48% decrease in repair time when PR is employed compared to the full bitstream configuration case.

  20. IUSThrust Vector Control (TVC) servo system

    Science.gov (United States)

    Conner, G. E.

    1979-01-01

    The IUS TVC SERVO SYSTEM which consists of four electrically redundant electromechanical actuators, four potentiometer assemblies, and two controllers to provide movable nozzle control on both IUS solid rocket motors is developed. An overview of the more severe IUS TVC servo system design requirements, the system and component designs, and test data acquired on a preliminary development unit is presented. Attention is focused on the unique methods of sensing movable nozzle position and providing for redundant position locks.

  1. Surface Magnetism of Cobalt Nanoislands Controlled by Atomic Hydrogen.

    Science.gov (United States)

    Park, Jewook; Park, Changwon; Yoon, Mina; Li, An-Ping

    2017-01-11

    Controlling the spin states of the surface and interface is key to spintronic applications of magnetic materials. Here, we report the evolution of surface magnetism of Co nanoislands on Cu(111) upon hydrogen adsorption and desorption with the hope of realizing reversible control of spin-dependent tunneling. Spin-polarized scanning tunneling microscopy reveals three types of hydrogen-induced surface superstructures, 1H-(2 × 2), 2H-(2 × 2), and 6H-(3 × 3), with increasing H coverage. The prominent magnetic surface states of Co, while being preserved at low H coverage, become suppressed as the H coverage level increases, which can then be recovered by H desorption. First-principles calculations reveal the origin of the observed magnetic surface states by capturing the asymmetry between the spin-polarized surface states and identify the role of hydrogen in controlling the magnetic states. Our study offers new insights into the chemical control of magnetism in low-dimensional systems.

  2. Polarization-controlled asymmetric excitation of surface plasmons

    KAUST Repository

    Xu, Quan; Zhang, Xueqian; Yang, Quanlong; Tian, Chunxiu; Xu, Yuehong; Zhang, Jianbing; Zhao, Hongwei; Li, Yanfeng; Ouyang, Chunmei; Tian, Zhen; Gu, Jianqiang; Zhang, Xixiang; Han, Jiaguang; Zhang, Weili

    2017-01-01

    Free-space light can be coupled into propagating surface waves at a metal–dielectric interface, known as surface plasmons (SPs). This process has traditionally faced challenges in preserving the incident polarization information and controlling

  3. Reactive oxygen species and nitric oxide in plant mitochondria: origin and redundant regulatory systems.

    Science.gov (United States)

    Blokhina, Olga; Fagerstedt, Kurt V

    2010-04-01

    Plant mitochondria differ from their mammalian counterparts in many respects, which are due to the unique and variable surroundings of plant mitochondria. In green leaves, plant mitochondria are surrounded by ample respiratory substrates and abundant molecular oxygen, both resulting from active photosynthesis, while in roots and bulky rhizomes and fruit carbohydrates may be plenty, whereas oxygen levels are falling. Several enzymatic complexes in mitochondrial electron transport chain (ETC) are capable of reactive oxygen species (ROS) formation under physiological and pathological conditions. Inherently connected parameters such as the redox state of electron carriers in the ETC, ATP synthase activity and inner mitochondrial membrane potential, when affected by external stimuli, can give rise to ROS formation via complexes I and III, and by reverse electron transport (RET) from complex II. Superoxide radicals produced are quickly scavenged by superoxide dismutase (MnSOD), and the resulting H(2)O(2) is detoxified by peroxiredoxin-thioredoxin system or by the enzymes of ascorbate-glutathione cycle, found in the mitochondrial matrix. Arginine-dependent nitric oxide (NO)-releasing activity of enzymatic origin has been detected in plant mitochondria. The molecular identity of the enzyme is not clear but the involvement of mitochondria-localized enzymes responsible for arginine catabolism, arginase and ornithine aminotransferase has been shown in the regulation of NO efflux. Besides direct control by antioxidants, mitochondrial ROS production is tightly controlled by multiple redundant systems affecting inner membrane potential: NAD(P)H-dependent dehydrogenases, alternative oxidase (AOX), uncoupling proteins, ATP-sensitive K(+) channel and a number of matrix and intermembrane enzymes capable of direct electron donation to ETC. NO removal, on the other hand, takes place either by reactions with molecular oxygen or superoxide resulting in peroxynitrite, nitrite or nitrate

  4. Revisions to Conventional Clock Domain Crossing Methodologies in Triple Modular Redundant Circuits

    Science.gov (United States)

    Berg, Melanie D.; LaBel, Kenneth A.

    2018-01-01

    We present updates to the conventional methodology of triple modular redundancy (TMR) insertion as it pertains to clock domain crossings (CDCs). Three types of TMR schemes and their suggested corresponding CDC revisions are discussed.

  5. Auto-Calibration and Fault Detection and Isolation of Skewed Redundant Accelerometers in Measurement While Drilling Systems.

    Science.gov (United States)

    Seyed Moosavi, Seyed Mohsen; Moaveni, Bijan; Moshiri, Behzad; Arvan, Mohammad Reza

    2018-02-27

    The present study designed skewed redundant accelerometers for a Measurement While Drilling (MWD) tool and executed auto-calibration, fault diagnosis and isolation of accelerometers in this tool. The optimal structure includes four accelerometers was selected and designed precisely in accordance with the physical shape of the existing MWD tool. A new four-accelerometer structure was designed, implemented and installed on the current system, replacing the conventional orthogonal structure. Auto-calibration operation of skewed redundant accelerometers and all combinations of three accelerometers have been done. Consequently, biases, scale factors, and misalignment factors of accelerometers have been successfully estimated. By defecting the sensors in the new optimal skewed redundant structure, the fault was detected using the proposed FDI method and the faulty sensor was diagnosed and isolated. The results indicate that the system can continue to operate with at least three correct sensors.

  6. Genome-wide CRISPR-Cas9 Screens Reveal Loss of Redundancy between PKMYT1 and WEE1 in Glioblastoma Stem-like Cells

    Directory of Open Access Journals (Sweden)

    Chad M. Toledo

    2015-12-01

    Full Text Available To identify therapeutic targets for glioblastoma (GBM, we performed genome-wide CRISPR-Cas9 knockout (KO screens in patient-derived GBM stem-like cells (GSCs and human neural stem/progenitors (NSCs, non-neoplastic stem cell controls, for genes required for their in vitro growth. Surprisingly, the vast majority GSC-lethal hits were found outside of molecular networks commonly altered in GBM and GSCs (e.g., oncogenic drivers. In vitro and in vivo validation of GSC-specific targets revealed several strong hits, including the wee1-like kinase, PKMYT1/Myt1. Mechanistic studies demonstrated that PKMYT1 acts redundantly with WEE1 to inhibit cyclin B-CDK1 activity via CDK1-Y15 phosphorylation and to promote timely completion of mitosis in NSCs. However, in GSCs, this redundancy is lost, most likely as a result of oncogenic signaling, causing GBM-specific lethality.

  7. Testing the race model inequality in redundant stimuli with variable onset asynchrony

    DEFF Research Database (Denmark)

    Gondan, Matthias

    2009-01-01

    distributions of response times for the single-modality stimuli. It has been derived for synchronous stimuli and for stimuli with stimulus onset asynchrony (SOA). In most experiments with asynchronous stimuli, discrete SOA values are chosen and the race model inequality is separately tested for each SOA. Due...... to SOAs at which the violation of the race model prediction is expected to be large. In addition, the method enables data analysis for experiments in which stimuli are presented with SOA from a continuous distribution rather than in discrete steps.......In speeded response tasks with redundant signals, parallel processing of the signals is tested by the race model inequality. This inequality states that given a race of two signals, the cumulative distribution of response times for redundant stimuli never exceeds the sum of the cumulative...

  8. A new way to improve the robustness of complex communication networks by allocating redundancy links

    International Nuclear Information System (INIS)

    Shi Chunhui; Zhuo Yue; Tang Jieying; Long Keping; Peng Yunfeng

    2012-01-01

    We investigate the robustness of complex communication networks on allocating redundancy links. The protecting key nodes (PKN) strategy is proposed to improve the robustness of complex communication networks against intentional attack. Our numerical simulations show that allocating a few redundant links among key nodes using the PKN strategy will significantly increase the robustness of scale-free complex networks. We have also theoretically proved and demonstrated the effectiveness of the PKN strategy. We expect that our work will help achieve a better understanding of communication networks. (paper)

  9. Flexible Procurement of Services with Uncertain Durations using Redundancy

    OpenAIRE

    Stein, S; Gerding, E; Rogers, A; Larson, K; Jennings, NR

    2009-01-01

    Emerging service-oriented technologies allow software agents to automatically procure distributed services to complete complex tasks. However, in many application scenarios, service providers demand financial remuneration, execution times are uncertain and consumers have deadlines for their tasks. In this paper, we address these issues by developing a novel approach that dynamically procures multiple, redundant services over time, in order to ensure success by the deadline. Specifically, we f...

  10. Computational and experimental analysis of redundancy in the central metabolism of Geobacter sulfurreducens.

    Directory of Open Access Journals (Sweden)

    Daniel Segura

    2008-02-01

    Full Text Available Previous model-based analysis of the metabolic network of Geobacter sulfurreducens suggested the existence of several redundant pathways. Here, we identified eight sets of redundant pathways that included redundancy for the assimilation of acetate, and for the conversion of pyruvate into acetyl-CoA. These equivalent pathways and two other sub-optimal pathways were studied using 5 single-gene deletion mutants in those pathways for the evaluation of the predictive capacity of the model. The growth phenotypes of these mutants were studied under 12 different conditions of electron donor and acceptor availability. The comparison of the model predictions with the resulting experimental phenotypes indicated that pyruvate ferredoxin oxidoreductase is the only activity able to convert pyruvate into acetyl-CoA. However, the results and the modeling showed that the two acetate activation pathways present are not only active, but needed due to the additional role of the acetyl-CoA transferase in the TCA cycle, probably reflecting the adaptation of these bacteria to acetate utilization. In other cases, the data reconciliation suggested additional capacity constraints that were confirmed with biochemical assays. The results demonstrate the need to experimentally verify the activity of key enzymes when developing in silico models of microbial physiology based on sequence-based reconstruction of metabolic networks.

  11. Operator-in-the-loop simulation of a redundant manipulator under teleoperation

    International Nuclear Information System (INIS)

    Yae, K.H.; Lin, T.C.; Chern, S.T.

    1993-01-01

    For an interactive simulation of 7 degree-of-freedom redundant manipulator under teleoperation, this paper describes an iterative form of resolved-motion rate control in which the constraint Jacobian is constructed on-line in real time and used in the pseudoinverse method as the manipulator is teleoperated. The manipulator's tasks may involve trajectory following in free space and frequent contact with the environment through pick-and-put operation. The operator's command is interpreted as a series of increments in Cartesian space, and then the constraint Jacobian is developed between two successive increments by viewing the predecessor as the initial configuration and the successor as the target configuration. The pseudoinverse of the constraint Jacobian then generates necessary changes in joint variables and subsequently joint torque. The Jacobian constructed in this way enables us to treat both free motion and environmental contact in the same way. The simulator is built on a two-processor IRIS workstation, with one processor for graphics and the other for dynamics and control analysis. This simulator has a potential for training the teleoperator, developing operational scenarios through visualization of the simulation, and testing the design of operator-machine interface

  12. The rise and fall of redundancy in decoherence and quantum Darwinism

    Science.gov (United States)

    Jess Riedel, C.; Zurek, Wojciech H.; Zwolak, Michael

    2012-08-01

    A state selected at random from the Hilbert space of a many-body system is overwhelmingly likely to exhibit highly non-classical correlations. For these typical states, half of the environment must be measured by an observer to determine the state of a given subsystem. The objectivity of classical reality—the fact that multiple observers can agree on the state of a subsystem after measuring just a small fraction of its environment—implies that the correlations found in nature between macroscopic systems and their environments are exceptional. Building on previous studies of quantum Darwinism showing that highly redundant branching states are produced ubiquitously during pure decoherence, we examine the conditions needed for the creation of branching states and study their demise through many-body interactions. We show that even constrained dynamics can suppress redundancy to the values typical of random states on relaxation timescales, and prove that these results hold exactly in the thermodynamic limit.

  13. Effect of a certain class of potential common mode failures on the reliability of redundant systems

    International Nuclear Information System (INIS)

    Apostolakis, G.E.

    1975-11-01

    This is a theoretical investigation of the importance of common mode failures on the reliability of redundant systems. These failures are assumed to be the result of fatal shocks (e.g., from earthquakes, explosions, etc.) which occur at a constant rate. This formulation makes it possible to predict analytically results obtained in the past which showed that the probability of a common mode failure of the redundant channels of the protection system of a typical nuclear power plant was orders of magnitude larger than the probability of failure from chance failures alone. Furthermore, since most reliability analyses of redundant systems do not include potential common mode failures in the probabilistic calculations, criteria are established which can be used to decide either that the common-mode-failure effects are indeed insignificant or that such calculations are meaningless, and more sophisticated methods of analysis are required, because common mode failures cannot be ignored

  14. Auto-Calibration and Fault Detection and Isolation of Skewed Redundant Accelerometers in Measurement While Drilling Systems

    Directory of Open Access Journals (Sweden)

    Seyed Mohsen Seyed Moosavi

    2018-02-01

    Full Text Available The present study designed skewed redundant accelerometers for a Measurement While Drilling (MWD tool and executed auto-calibration, fault diagnosis and isolation of accelerometers in this tool. The optimal structure includes four accelerometers was selected and designed precisely in accordance with the physical shape of the existing MWD tool. A new four-accelerometer structure was designed, implemented and installed on the current system, replacing the conventional orthogonal structure. Auto-calibration operation of skewed redundant accelerometers and all combinations of three accelerometers have been done. Consequently, biases, scale factors, and misalignment factors of accelerometers have been successfully estimated. By defecting the sensors in the new optimal skewed redundant structure, the fault was detected using the proposed FDI method and the faulty sensor was diagnosed and isolated. The results indicate that the system can continue to operate with at least three correct sensors.

  15. Effects of redundancy in the comparison of speech and pictorial displays in the cockpit environment.

    Science.gov (United States)

    Byblow, W D

    1990-06-01

    Synthesised speech and pictorial displays were compared in a spatially compatible simulated cockpit environment. Messages of high or low levels of redundancy were presented to subjects in both modality conditions. Subjects responded to warnings presented in a warning-only condition and in a dual-task condition, in which a simulated flight task was performed with visual and manual input/output modalities. Because the amount of information presented in most real-world applications and experimental paradigms is quantifiably large with respect to present guidelines for the use of synthesised speech warnings, the low-redundancy condition was hypothesised to allow for better performance. Results showed that subjects respond quicker to messages of low redundancy in both modalities. It is suggested that speech messages with low-redundancy levels were effective in minimising message length and ensuring that messages did not overload the short-term memory required to process and maintain speech in memory. Manipulation of phrase structure was used to optimise message redundancy and enhance the conceptual compatibility of the message without increasing message length or imposing a perceptual cost or memory overload. The results also suggest that system response times were quicker when synthesised speech warnings were used. This result is consistent with predictions from multiple resource theory which states that the resources required for the perception of verbal warnings are different from those for the flight task. It is also suggested that the perception of a pictorial display requires the same resources used for the perception of the primary flight task. An alternative explanation is that pictorial displays impose a visual scanning cost which is responsible for decreased performance. Based on the findings reported here, it is suggested that speech displays be incorporated in a spatially compatible cockpit environment because they allow equal or better performance when

  16. RedThreads: An Interface for Application-Level Fault Detection/Correction Through Adaptive Redundant Multithreading

    International Nuclear Information System (INIS)

    Hukerikar, Saurabh; Teranishi, Keita; Diniz, Pedro C.; Lucas, Robert F.

    2017-01-01

    In the presence of accelerated fault rates, which are projected to be the norm on future exascale systems, it will become increasingly difficult for high-performance computing (HPC) applications to accomplish useful computation. Due to the fault-oblivious nature of current HPC programming paradigms and execution environments, HPC applications are insufficiently equipped to deal with errors. We believe that HPC applications should be enabled with capabilities to actively search for and correct errors in their computations. The redundant multithreading (RMT) approach offers lightweight replicated execution streams of program instructions within the context of a single application process. Furthermore, the use of complete redundancy incurs significant overhead to the application performance.

  17. Microprocessor-controlled surface testing

    Energy Technology Data Exchange (ETDEWEB)

    Droscha, H

    1982-09-01

    For the quality inspection on continuous flow material webs with transverse scanning laser beam, the microprocessor control, realized now for the first time in combination with appropriate units, shows a considerable progress. Thanks to the here used electronics, surface errors can be localized within the web according to their x-y-position, quantitative analysis can be carried out and automatic sorting and registration functions can be used.

  18. The common mode failures analysis of the redundent system with dependent human error

    International Nuclear Information System (INIS)

    Kim, M.K.; Chang, S.H.

    1983-01-01

    Common mode failures (CMFs) have been a serious concern in the nuclear power plant. Thereis a broad category of the failure mechanisms that can cause common mode failures. This paper is a theoretical investigation of the CMFs on the unavailability of the redundent system. It is assumed that the total CMFs consist of the potential CMFs and the dependent human error CMFs. As the human error dependency is higher, the total CMFs are more effected by the dependent human error. If the human error dependence is lower, the system unavailability strongly depends on the potential CMFs, rather than the mechanical failure or the dependent human error. And it is shown that the total CMFs are dominant factor to the unavailability of the redundent system. (Author)

  19. Dislocation behavior of surface-oxygen-concentration controlled Si wafers

    International Nuclear Information System (INIS)

    Asazu, Hirotada; Takeuchi, Shotaro; Sannai, Hiroya; Sudo, Haruo; Araki, Koji; Nakamura, Yoshiaki; Izunome, Koji; Sakai, Akira

    2014-01-01

    We have investigated dislocation behavior in the surface area of surface-oxygen-concentration controlled Si wafers treated by a high temperature rapid thermal oxidation (HT-RTO). The HT-RTO process allows us to precisely control the interstitial oxygen concentration ([O i ]) in the surface area of the Si wafers. Sizes of rosette patterns, generated by nano-indentation and subsequent thermal annealing at 900 °C for 1 h, were measured for the Si wafers with various [O i ]. It was found that the rosette size decreases in proportion to the − 0.25 power of [O i ] in the surface area of the Si wafers, which were higher than [O i ] of 1 × 10 17 atoms/cm 3 . On the other hand, [O i ] of lower than 1 × 10 17 atoms/cm 3 did not affect the rosette size very much. These experimental results demonstrate the ability of the HT-RTO process to suppress the dislocation movements in the surface area of the Si wafer. - Highlights: • Surface-oxygen-concentration controlled Si wafers have been made. • The oxygen concentration was controlled by high temperature rapid thermal oxidation. • Dislocation behavior in the surface area of the Si wafers has been investigated. • Rosette size decreased with increasing of interstitial oxygen atoms. • The interstitial oxygen atoms have a pinning effect of dislocations at the surface

  20. Piezoelectric composite morphing control surfaces for unmanned aerial vehicles

    Science.gov (United States)

    Ohanian, Osgar J., III; Karni, Etan D.; Olien, Chris C.; Gustafson, Eric A.; Kochersberger, Kevin B.; Gelhausen, Paul A.; Brown, Bridget L.

    2011-04-01

    The authors have explored the use of morphing control surfaces to replace traditional servo-actuated control surfaces in UAV applications. The morphing actuation is accomplished using Macro Fiber Composite (MFC) piezoelectric actuators in a bimorph configuration to deflect the aft section of a control surface cross section. The resulting camber change produces forces and moments for vehicle control. The flexible piezoelectric actuators are damage tolerant and provide excellent bandwidth. The large amplitude morphing deflections attained in bench-top experiments demonstrate the potential for excellent control authority. Aerodynamic performance calculations using experimentally measured morphed geometries indicate changes in sectional lift coefficients that are superior to a servo-actuated hinged flap airfoil. This morphing flight control actuation technology could eliminate the need for servos and mechanical linkages in small UAVs and thereby increase reliability and reduce drag.

  1. The conservation of redundancy in genetic systems: effects of sexual ...

    Indian Academy of Sciences (India)

    Unknown

    probability of a fatal error is reduced by a redundant sampling system, but the chance of error rises as the sys- .... Thus every function is covered three times and every component covers a ... ples reduce the variance of the distributions in figure 3a and thereby ..... cases p = 0⋅1, q = 1000 and the value of b is adjusted to.

  2. Comparative efficacy and safety of different circumcisions for patients with redundant prepuce or phimosis: A network meta-analysis.

    Science.gov (United States)

    Huang, Chuiguo; Song, Pan; Xu, Changbao; Wang, Ruofan; Wei, Lei; Zhao, Xinghua

    2017-07-01

    Phimosis and redundant prepuce are defined as the inability of the foreskin to be retracted behind the glans penis in uncircumcised males. To synthesize the evidence and provide the hierarchies of different circumcisions for phimosis and redundant prepuce, we performed an overall network meta-analysis (NMA) based on their comparative efficacy and safety. Electronic databases including PubMed, Embase, Wan Fang, VIP, CNKI and CBM database were researched from randomized controlled trials (RCTs) for redundant prepuce or phimosis. We conducted the direct and indirect comparisons by aggregate data drug information system (ADDIS) software. Moreover, consistency models were applied to assess the differences among the male circumcision practices, and the ranks based on probabilities of intervention for the different endpoints were performed. Node-splitting analysis was used to test inconsistency. Eighteen RCTs were included with 6179 participants. Compared with the conventional circumcision(CC), two new styles of circumcisions, the disposable circumcision suture device(DCSD) and Shang Ring circumcision(SRC), provided significantly shorter operation time[DCSD: standardized mean difference (SMD) = -20.60, 95% credible interval(CI) (-23.38, -17.82); SRC: SMD = -19.16, 95%CI (-21.86, -16.52)], shorter wound healing time [DCSD:SMD = -4.19, 95%CI (-8.24,-0.04); SRC: SMD = 4.55, 95%CI (1.62, 7.57); ] and better postoperative penile appearance [DCSD: odds ratios odds ratios (OR) = 11.42, 95%CI (3.60, 37.68); SRC: OR = 3.85,95%CI (1.29, 12.79)]. Additionally, DCSD showed a lower adverse events rate than other two treatments. However, no significant difference was shown in all surgeries for 24 h postoperative pain score. Node-splitting analysis showed that no significant inconsistency was existed (P > 0.05). Based on the results of NMA, DCSD may be a most effective and safest choice for phimosis and redundant prepuce. DCSD has the advantages of a shorter operation

  3. SURFACE TEXTURE ANALYSIS FOR FUNCTIONALITY CONTROL

    DEFF Research Database (Denmark)

    De Chiffre, Leonardo; Andreasen, Jan Lasson; Tosello, Guido

    This document is used in connection with three exercises of 3 hours duration as a part of the course VISION ONLINE – One week course on Precision & Nanometrology. The exercises concern surface texture analysis for functionality control, in connection with three different case stories. This docume...... contains a short description of each case story, 3-D roughness parameters analysis and relation with the product’s functionality.......This document is used in connection with three exercises of 3 hours duration as a part of the course VISION ONLINE – One week course on Precision & Nanometrology. The exercises concern surface texture analysis for functionality control, in connection with three different case stories. This document...

  4. Effective use of surface-water management to control saltwater intrusion

    Science.gov (United States)

    Hughes, J. D.; White, J.

    2012-12-01

    The Biscayne aquifer in southeast Florida is susceptible to saltwater intrusion and inundation from rising sea-level as a result of high groundwater withdrawal rates and low topographic relief. Groundwater levels in the Biscayne aquifer are managed by an extensive canal system that is designed to control flooding, supply recharge to municipal well fields, and control saltwater intrusion. We present results from an integrated surface-water/groundwater model of a portion of the Biscayne aquifer to evaluate the ability of the existing managed surface-water control network to control saltwater intrusion. Surface-water stage and flow are simulated using a hydrodynamic model that solves the diffusive-wave approximation of the depth-integrated shallow surface-water equations. Variable-density groundwater flow and fluid density are solved using the Oberbeck--Boussinesq approximation of the three-dimensional variable-density groundwater flow equation and a sharp interface approximation, respectively. The surface-water and variable-density groundwater domains are implicitly coupled during each Picard iteration. The Biscayne aquifer is discretized into a multi-layer model having a 500-m square horizontal grid spacing. All primary and secondary surface-water features in the active model domain are discretized into segments using the 500-m square horizontal grid. A 15-year period of time is simulated and the model includes 66 operable surface-water control structures, 127 municipal production wells, and spatially-distributed daily internal and external hydrologic stresses. Numerical results indicate that the existing surface-water system can be effectively used in many locations to control saltwater intrusion in the Biscayne aquifer resulting from increases in groundwater withdrawals or sea-level rise expected to occur over the next 25 years. In other locations, numerical results indicate surface-water control structures and/or operations may need to be modified to control

  5. Evaluation of Surface Modification as a Lunar Dust Mitigation Strategy for Thermal Control Surfaces

    Science.gov (United States)

    Gaier, James R.; Waters, Deborah L.; Misconin, Robert M.; Banks, Bruce A.; Crowder, Mark

    2011-01-01

    Three surface treatments were evaluated for their ability to lower the adhesion between lunar simulant dust and AZ93, AlFEP, and AgFEP thermal control surfaces under simulated lunar conditions. Samples were dusted in situ and exposed to a standardized puff of nitrogen gas. Thermal performance before dusting, after dusting, and after part of the dust was removed by the puff of gas, were compared to perform the assessment. None of the surface treatments was found to significantly affect the adhesion of lunar simulants to AZ93 thermal control paint. Oxygen ion beam texturing also did not lower the adhesion of lunar simulant dust to AlFEP or AgFEP. But a workfunction matching coating and a proprietary Ball Aerospace surface treatment were both found to significantly lower the adhesion of lunar simulants to AlFEP and AgFEP. Based on these results, it is recommended that all these two techniques be further explored as dust mitigation coatings for AlFEP and AgFEP thermal control surfaces.

  6. Variational reconstruction using subdivision surfaces with continuous sharpness control

    Institute of Scientific and Technical Information of China (English)

    Xiaoqun Wu; Jianmin Zheng; Yiyu Cai; Haisheng Li

    2017-01-01

    We present a variational method for subdivision surface reconstruction from a noisy dense mesh.A new set of subdivision rules with continuous sharpness control is introduced into Loop subdivision for better modeling subdivision surface features such as semi-sharp creases,creases,and corners.The key idea is to assign a sharpness value to each edge of the control mesh to continuously control the surface features.Based on the new subdivision rules,a variational model with L1 norm is formulated to find the control mesh and the corresponding sharpness values of the subdivision surface that best fits the input mesh.An iterative solver based on the augmented Lagrangian method and particle swarm optimization is used to solve the resulting non-linear,non-differentiable optimization problem.Our experimental results show that our method can handle meshes well with sharp/semi-sharp features and noise.

  7. Integrated Application of Active Controls (IAAC) technology to an advanced subsonic transpot project-demonstration act system definition

    Science.gov (United States)

    Hanks, G. W.; Shomber, H. A.; Crumb, C. B.; Flora, C. C.; Macdonald, K. A. B.; Smith, R. D.; Sassi, A. P.; Dorwart, R. J.

    1982-01-01

    The 1985 ACT airplane is the Final Active Controls Technology (ACT) Airplane with the addition of three-axis fly by wire. Thus it retains all the efficiency features of the full ACT system plus the weight and cost savings accruing from deletion of the mechanical control system. The control system implements the full IAAC spectrum of active controls except flutter-mode control, judged essentially nonbeneficial, and incorporates new control surfaces called flaperons to make the most of wing-load alleviation. This redundant electronic system is conservatively designed to preserve the extreme reliability required of crucial short-period pitch augmentation, which provides more than half of the fuel savings.

  8. Two-dimensional servo control of surface motor; Surface motor no nijigen servo control

    Energy Technology Data Exchange (ETDEWEB)

    Ebihara, D; Takahashi, T; Watada, M [Musashi Institute of Technology, Tokyo (Japan)

    1995-08-20

    Two dimensional (2D) drive system is needed in many aspects of factory automation (FA) and office automation (OA) machines, such as pen drivers in X-Y plotters, X-Y stage for machining, 2D moving robots, etc. Conventional 2D drive systems are consisted from two sets of rotational motor drive and several types of rotary-to-linear transform mechanisms. Linear motors, in these days, have become to be effective as the requirement for high speed increases. We have been studying about Surface Motor which enables 2D drive on a surface by single mover, and the characteristics are measured. Main difficulty of the actuator is that it is short of thrust forces. Also the feasibility is limited because of its vocational uncertainty caused by the open loop control. Our interest is to introduce the closed loop digital control, to obtain required thrust force at any point on the stator. Since open loop control is used, that is, stability point where the thrust force is zero is moved one after another, generated thrust force within the range of synchronization is small. We have been studying about the peculiar expression of exciting currents to generate required direction at all the stator. On the basis of results, two dimensional position feedback system is assembled, which detect the two dimensional location of the mover by optical sensors and direct current instructions are generated for all the four phases of the mover. 14 refs., 11 figs., 1 tab.

  9. Distributed process control system for remote control and monitoring of the TFTR tritium systems

    International Nuclear Information System (INIS)

    Schobert, G.; Arnold, N.; Bashore, D.; Mika, R.; Oliaro, G.

    1989-01-01

    This paper reviews the progress made in the application of a commercially available distributed process control system to support the requirements established for the Tritium REmote Control And Monitoring System (TRECAMS) of the Tokamak Fusion Test REactor (TFTR). The system that will discussed was purchased from Texas (TI) Instruments Automation Controls Division), previously marketed by Rexnord Automation. It consists of three, fully redundant, distributed process controllers interfaced to over 1800 analog and digital I/O points. The operator consoles located throughout the facility are supported by four Digital Equipment Corporation (DEC) PDP-11/73 computers. The PDP-11/73's and the three process controllers communicate over a fully redundant one megabaud fiber optic network. All system functionality is based on a set of completely integrated databases loaded to the process controllers and the PDP-11/73's. (author). 2 refs.; 2 figs

  10. The Public Collaboration Lab—Infrastructuring Redundancy with Communities-in-Place

    Directory of Open Access Journals (Sweden)

    Adam Thorpe

    Full Text Available In this article we share an example of challenge-driven learning in design education and consider the contribution of such approaches to the weaving of communities-in-place. We describe the research and practice of the Public Collaboration Lab (PCL, a prototype public social innovation lab developed and tested via a collaborative action research partnership between a London borough council and an art and design university. We make the case that this collaboration is an effective means of bringing capacity in design to public service innovation, granting the redundancy of resources necessary for the experimentation, reflection, and learning that leads to innovation—particularly at a time of financial austerity. We summarize three collaborative design experiments delivered by local government officers working with student designers and residents supported by design researchers and tutors. We identify particular qualities of participatory and collaborative design that foster the construction of meaningful connections among participants in the design process—connections that have the potential to catalyze or strengthen the relationships, experiences, and understandings that contribute to enrich communities-in-place, and infrastructure community resilience in the process. Keywords: Participatory design, Public social innovation, Redundancy, Infrastructuring, Local government

  11. Design and reliability analysis of DP-3 dynamic positioning control architecture

    Science.gov (United States)

    Wang, Fang; Wan, Lei; Jiang, Da-Peng; Xu, Yu-Ru

    2011-12-01

    As the exploration and exploitation of oil and gas proliferate throughout deepwater area, the requirements on the reliability of dynamic positioning system become increasingly stringent. The control objective ensuring safety operation at deep water will not be met by a single controller for dynamic positioning. In order to increase the availability and reliability of dynamic positioning control system, the triple redundancy hardware and software control architectures were designed and developed according to the safe specifications of DP-3 classification notation for dynamically positioned ships and rigs. The hardware redundant configuration takes the form of triple-redundant hot standby configuration including three identical operator stations and three real-time control computers which connect each other through dual networks. The function of motion control and redundancy management of control computers were implemented by software on the real-time operating system VxWorks. The software realization of task loose synchronization, majority voting and fault detection were presented in details. A hierarchical software architecture was planed during the development of software, consisting of application layer, real-time layer and physical layer. The behavior of the DP-3 dynamic positioning control system was modeled by a Markov model to analyze its reliability. The effects of variation in parameters on the reliability measures were investigated. The time domain dynamic simulation was carried out on a deepwater drilling rig to prove the feasibility of the proposed control architecture.

  12. Hardware for Accelerating N-Modular Redundant Systems for High-Reliability Computing

    Science.gov (United States)

    Dobbs, Carl, Sr.

    2012-01-01

    A hardware unit has been designed that reduces the cost, in terms of performance and power consumption, for implementing N-modular redundancy (NMR) in a multiprocessor device. The innovation monitors transactions to memory, and calculates a form of sumcheck on-the-fly, thereby relieving the processors of calculating the sumcheck in software

  13. Anomalous Surface Wave Launching by Handedness Phase Control

    KAUST Repository

    Zhang, Xueqian

    2015-10-09

    Anomalous launch of a surface wave with different handedness phase control is achieved in a terahertz metasurface based on phase discontinuities. The polarity of the phase profile of the surface waves is found to be strongly correlated to the polarization handedness, promising polarization-controllable wavefront shaping, polarization sensing, and environmental refractive-index sensing. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Anomalous Surface Wave Launching by Handedness Phase Control

    KAUST Repository

    Zhang, Xueqian; Xu, Yuehong; Yue, Weisheng; Tian, Zhen; Gu, Jianqiang; Li, Yanfeng; Singh, Ranjan; Zhang, Shuang; Han, Jiaguang; Zhang, Weili

    2015-01-01

    Anomalous launch of a surface wave with different handedness phase control is achieved in a terahertz metasurface based on phase discontinuities. The polarity of the phase profile of the surface waves is found to be strongly correlated to the polarization handedness, promising polarization-controllable wavefront shaping, polarization sensing, and environmental refractive-index sensing. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. A Review of Multimedia Learning Principles: Split-Attention, Modality, and Redundancy Effects

    Directory of Open Access Journals (Sweden)

    Pelin YUKSEL ARSLAN

    2012-02-01

    Full Text Available This study aims to present a literature review on three principles of multimedia learningincluding split attention, modality, and redundancy effects with regard to their contribution to cognitiveload theory. According to cognitive load theory, information should be presented by considering excessiveload on working memory. The first principle states that attending to two distinct sources of informationmay impose a high cognitive load, and this process is referred to as the split-attention effect (Kalyuga,Chandler & Sweller, 1991, 1992. The second principle, Modality effect claims that on-screen text shouldbe presented in an auditory form instead of visually when designing a multimedia environment (Moreno &Mayer, 1999. Using more than one sensory mode augments forceful working memory that producesprogressive effects on learning. The third principle redundancy effect occurs when information presentedrepeatedly interferes with learning. This study provides guidance how to create more effective instructionwith multimedia materials for instructional designers.

  16. Modified Redundancy based Technique—a New Approach to Combat Error Propagation Effect of AES

    Science.gov (United States)

    Sarkar, B.; Bhunia, C. T.; Maulik, U.

    2012-06-01

    Advanced encryption standard (AES) is a great research challenge. It has been developed to replace the data encryption standard (DES). AES suffers from a major limitation of error propagation effect. To tackle this limitation, two methods are available. One is redundancy based technique and the other one is bite based parity technique. The first one has a significant advantage of correcting any error on definite term over the second one but at the cost of higher level of overhead and hence lowering the processing speed. In this paper, a new approach based on the redundancy based technique is proposed that would certainly speed up the process of reliable encryption and hence the secured communication.

  17. Adaptive increase in force variance during fatigue in tasks with low redundancy.

    Science.gov (United States)

    Singh, Tarkeshwar; S K M, Varadhan; Zatsiorsky, Vladimir M; Latash, Mark L

    2010-11-26

    We tested a hypothesis that fatigue of an element (a finger) leads to an adaptive neural strategy that involves an increase in force variability in the other finger(s) and an increase in co-variation of commands to fingers to keep total force variability relatively unchanged. We tested this hypothesis using a system with small redundancy (two fingers) and a marginally redundant system (with an additional constraint related to the total moment of force produced by the fingers, unstable condition). The subjects performed isometric accurate rhythmic force production tasks by the index (I) finger and two fingers (I and middle, M) pressing together before and after a fatiguing exercise by the I finger. Fatigue led to a large increase in force variance in the I-finger task and a smaller increase in the IM-task. We quantified two components of variance in the space of hypothetical commands to fingers, finger modes. Under both stable and unstable conditions, there was a large increase in the variance component that did not affect total force and a much smaller increase in the component that did. This resulted in an increase in an index of the force-stabilizing synergy. These results indicate that marginal redundancy is sufficient to allow the central nervous system to use adaptive increase in variability to shield important variables from effects of fatigue. We offer an interpretation of these results based on a recent development of the equilibrium-point hypothesis known as the referent configuration hypothesis. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  18. Assessment of redundant systems with imperfect coverage by means of binary decision diagrams

    Energy Technology Data Exchange (ETDEWEB)

    Myers, Albert F. [Northrop Grumman Corporation, 1840 Century Park East, Los Angeles, CA 90067-2199 (United States)], E-mail: Al.Myers@ngc.com; Rauzy, Antoine [IML/CNRS, 163, Avenue de Luminy, 13288 Marseille Cedex 09 (France)], E-mail: arauzy@iml.univ-mrs.fr

    2008-07-15

    In this article, we study the assessment of the reliability of redundant systems with imperfect fault coverage. We term fault coverage as the ability of a system to isolate and correctly accommodate failures of redundant elements. For highly reliable systems, such as avionic and space systems, fault coverage is in general imperfect and has a significant impact on system reliability. We review here the different models of imperfect fault coverage. We propose efficient algorithms to assess them separately (as k-out-of-n selectors). We show how to implement these algorithms into a binary decision diagrams engine. Finally, we report experimental results on real life test cases that show on the one hand the importance of imperfect coverage and on the other hand the efficiency of the proposed approach.

  19. Mature neurons dynamically restrict apoptosis via redundant premitochondrial brakes.

    Science.gov (United States)

    Annis, Ryan P; Swahari, Vijay; Nakamura, Ayumi; Xie, Alison X; Hammond, Scott M; Deshmukh, Mohanish

    2016-12-01

    Apoptotic cell death is critical for the early development of the nervous system, but once the nervous system is established, the apoptotic pathway becomes highly restricted in mature neurons. However, the mechanisms underlying this increased resistance to apoptosis in these mature neurons are not completely understood. We have previously found that members of the miR-29 family of microRNAs (miRNAs) are induced with neuronal maturation and that overexpression of miR-29 was sufficient to restrict apoptosis in neurons. To determine whether endogenous miR-29 alone was responsible for the inhibition of cytochrome c release in mature neurons, we examined the status of the apoptotic pathway in sympathetic neurons deficient for all three miR-29 family members. Unexpectedly, we found that the apoptotic pathway remained largely restricted in miR-29-deficient mature neurons. We therefore probed for additional mechanisms by which mature neurons resist apoptosis. We identify miR-24 as another miRNA that is upregulated in the maturing cerebellum and sympathetic neurons that can act redundantly with miR-29 by targeting a similar repertoire of prodeath BH3-only genes. Overall, our results reveal that mature neurons engage multiple redundant brakes to restrict the apoptotic pathway and ensure their long-term survival. © 2016 Federation of European Biochemical Societies.

  20. Reversible Compositional Control of Oxide Surfaces by Electrochemical Potentials

    KAUST Repository

    Mutoro, Eva

    2012-01-05

    Perovskite oxides can exhibit a wide range of interesting characteristics such as being catalytically active and electronically/ionically conducting, and thus, they have been used in a number of solid-state devices such as solid oxide fuel cells (SOFCs) and sensors. As the surface compositions of perovskites can greatly influence the catalytic properties, knowing and controlling their surface compositions is crucial to enhance device performance. In this study, we demonstrate that the surface strontium (Sr) and cobalt (Co) concentrations of perovskite-based thin films can be controlled reversibly at elevated temperatures by applying small electrical potential biases. The surface compositional changes of La 0.8Sr 0.2CoO 3-δ (LSC 113), (La 0.5Sr 0.5) 2CoO 4±δ (LSC 214), and LSC 214-decorated LSC 113 films (LSC 113/214) were investigated in situ by utilizing synchrotron-based X-ray photoelectron spectroscopy (XPS), where the largest changes of surface Sr were found for the LSC 113/214 surface. These findings offer the potential of reversibly controlling the surface functionality of perovskites. © 2011 American Chemical Society.

  1. ERECTA-family receptor kinase genes redundantly prevent premature progression of secondary growth in the Arabidopsis hypocotyl.

    Science.gov (United States)

    Ikematsu, Shuka; Tasaka, Masao; Torii, Keiko U; Uchida, Naoyuki

    2017-03-01

    Secondary growth is driven by continuous cell proliferation and differentiation of the cambium that acts as vascular stem cells, producing xylem and phloem to expand vascular tissues laterally. During secondary growth of hypocotyls in Arabidopsis thaliana, the xylem undergoes a drastic phase transition from a parenchyma-producing phase to a fiber-producing phase at the appropriate time. However, it remains to be fully elucidated how progression of secondary growth is properly controlled. We focused on phenotypes of hypocotyl vasculatures caused by double mutation in ERECTA (ER) and ER-LIKE1 (ERL1) receptor-kinase genes to elucidate their roles in secondary growth. ER and ERL1 redundantly suppressed excessive radial growth of the hypocotyl vasculature during secondary growth. ER and ERL1 also prevented premature initiation of the fiber differentiation process mediated by the NAC SECONDARY WALL THICKENING PROMOTING FACTORs in the hypocotyl xylem. Upon floral transition, the hypocotyl xylem gained a competency to respond to GA in a BREVIPEDICELLUS-dependent manner, which was a prerequisite for fiber differentiation. However, even after the floral transition, ER and ERL1 prevented precocious initiation of the GA-mediated fiber formation. Collectively, our findings reveal that ER and ERL1 redundantly prevent premature progression of sequential events in secondary growth. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

  2. Surface effects in controlled thermonuclear fusion

    International Nuclear Information System (INIS)

    Kaminsky, M.

    1975-08-01

    During the operation of large size plasma facilities and future controlled thermonuclear fusion reactors the surfaces of such major components as container walls, beam limiters, diverter walls and beam-dump walls of the injector region will be exposed to particle and photon bombardment from primary plasma radiations and from secondary radiations. Such radiations can cause, for example, physical and chemical sputtering, blistering, particle- and photon-impact induced desorption, secondary electron and x-ray emission, backscattering, nuclear reactions, photo-decomposition of surface compounds, photocatalysis, and vaporization. Such effects in turn can (a) seriously damage and erode the bombarded surface and (b) release major quantities of impurities which will contaminate the plasma. The effects of some of the major surface phenomena on the operation of plasma facilities and future fusion reactors are discussed

  3. Does functional redundancy stabilize fish communities?

    DEFF Research Database (Denmark)

    Rice, Jake; Daan, Niels; Gislason, Henrik

    2013-01-01

    in abundance or biomass could be accounted for by the Law of Large Numbers, providing no evidence that specific ecological processes or co-adaptations are necessary to produce this effect. This implies that successful conservation policies to maintain the resilience of a marine fish community could be based......Functional redundancy of species sharing a feeding strategy and/or maximum size has been hypothesized to contribute to increased resilience of marine fish communities (the “portfolio effect”). A consistent time-series of survey data of fish in the North Sea was used to examine if trophic functional...... groups or maximum length of species (Lmax) groups with larger numbers of species had lower coefficients of variation in abundance and biomass over time than did groupings with fewer species. Results supported this hypothesis. However, the stabilizing effect of numbers of species in a group on variation...

  4. Surface-Controlled Metal Oxide Resistive Memory

    KAUST Repository

    Ke, Jr-Jian; Namura, Kyoko; Duran Retamal, Jose Ramon; Ho, Chin-Hsiang; Minamitake, Haruhiko; Wei, Tzu-Chiao; Tsai, Dung-Sheng; Lin, Chun-Ho; Suzuki, Motofumi; He, Jr-Hau

    2015-01-01

    be attributed to the stable oxygen adatoms under various ambience conditions. The findings validate the surface-controlled stability and uniformity of ReRAM and can serve as the guideline for developing practical device applications.

  5. . Redundancy and blocking in the spatial domain: A connectionist model

    Directory of Open Access Journals (Sweden)

    I. P. L. Mc Laren

    2002-01-01

    Full Text Available How can the observations of spatial blocking (Rodrigo, Chamizo, McLaren & Mackintosh, 1997 and cue redundancy (O’Keefe and Conway, 1978 be reconciled within the framework provided by an error-correcting, connectionist account of spatial navigation? I show that an implementation of McLaren’s (1995 better beta model can serve this purpose, and examine some of the implications for spatial learning and memory.

  6. Surface roughness control by extreme ultraviolet (EUV) radiation

    Science.gov (United States)

    Ahad, Inam Ul; Obeidi, Muhannad Ahmed; Budner, Bogusław; Bartnik, Andrzej; Fiedorowicz, Henryk; Brabazon, Dermot

    2017-10-01

    Surface roughness control of polymeric materials is often desirable in various biomedical engineering applications related to biocompatibility control, separation science and surface wettability control. In this study, Polyethylene terephthalate (PET) polymer films were irradiated with Extreme ultraviolet (EUV) photons in nitrogen environment and investigations were performed on surface roughness modification via EUV exposure. The samples were irradiated at 3 mm and 4 mm distance from the focal spot to investigate the effect of EUV fluence on topography. The topography of the EUV treated PET samples were studied by AFM. The detailed scanning was also performed on the sample irradiated at 3 mm. It was observed that the average surface roughness of PET samples was increased from 9 nm (pristine sample) to 280 nm and 253 nm for EUV irradiated samples. Detailed AFM studies confirmed the presence of 1.8 mm wide period U-shaped channels in EUV exposed PET samples. The walls of the channels were having FWHM of about 0.4 mm. The channels were created due to translatory movements of the sample in horizontal and transverse directions during the EUV exposure. The increased surface roughness is useful for many applications. The nanoscale channels fabricated by EUV exposure could be interesting for microfluidic applications based on lab-on-a-chip (LOC) devices.

  7. CCF analysis of high redundancy systems safety/relief valve data analysis and reference BWR application

    International Nuclear Information System (INIS)

    Mankamo, T.; Bjoere, S.; Olsson, Lena

    1992-12-01

    Dependent failure analysis and modeling were developed for high redundancy systems. The study included a comprehensive data analysis of safety and relief valves at the Finnish and Swedish BWR plants, resulting in improved understanding of Common Cause Failure mechanisms in these components. The reference application on the Forsmark 1/2 reactor relief system, constituting of twelve safety/relief lines and two regulating relief lines, covered different safety criteria cases of reactor depressurization and overpressure protection function, and failure to re close sequences. For the quantification of dependencies, the Alpha Factor Model, the Binomial Probability Model and the Common Load Model were compared for applicability in high redundancy systems

  8. Design and simulation of the surface shape control system for membrane mirror

    Science.gov (United States)

    Zhang, Gengsheng; Tang, Minxue

    2009-11-01

    The surface shape control is one of the key technologies for the manufacture of membrane mirror. This paper presents a design of membrane mirror's surface shape control system on the basis of fuzzy logic control. The system contains such function modules as surface shape design, surface shape control, surface shape analysis, and etc. The system functions are realized by using hybrid programming technology of Visual C# and MATLAB. The finite element method is adopted to simulate the surface shape control of membrane mirror. The finite element analysis model is established through ANSYS Parametric Design Language (APDL). ANSYS software kernel is called by the system in background running mode when doing the simulation. The controller is designed by means of controlling the sag of the mirror's central crosssection. The surface shape of the membrane mirror and its optical aberration are obtained by applying Zernike polynomial fitting. The analysis of surface shape control and the simulation of disturbance response are performed for a membrane mirror with 300mm aperture and F/2.7. The result of the simulation shows that by using the designed control system, the RMS wavefront error of the mirror can reach to 142λ (λ=632.8nm), which is consistent to the surface accuracy of the membrane mirror obtained by the large deformation theory of membrane under the same condition.

  9. The theory of diversity and redundancy in information system security : LDRD final report.

    Energy Technology Data Exchange (ETDEWEB)

    Mayo, Jackson R. (Sandia National Laboratories, Livermore, CA); Torgerson, Mark Dolan; Walker, Andrea Mae; Armstrong, Robert C. (Sandia National Laboratories, Livermore, CA); Allan, Benjamin A. (Sandia National Laboratories, Livermore, CA); Pierson, Lyndon George

    2010-10-01

    The goal of this research was to explore first principles associated with mixing of diverse implementations in a redundant fashion to increase the security and/or reliability of information systems. Inspired by basic results in computer science on the undecidable behavior of programs and by previous work on fault tolerance in hardware and software, we have investigated the problem and solution space for addressing potentially unknown and unknowable vulnerabilities via ensembles of implementations. We have obtained theoretical results on the degree of security and reliability benefits from particular diverse system designs, and mapped promising approaches for generating and measuring diversity. We have also empirically studied some vulnerabilities in common implementations of the Linux operating system and demonstrated the potential for diversity to mitigate these vulnerabilities. Our results provide foundational insights for further research on diversity and redundancy approaches for information systems.

  10. Optimization of redundancy by using genetic algorithm for reliability of plant protection system

    International Nuclear Information System (INIS)

    Yoo, D. W.; Seong, S. H.; Kim, D. H.; Park, H. Y.; Gu, I. S.

    2000-01-01

    The design and development of a reliable protection system has been becoming a key issue in industry field because the reliability of system is considered as an important factor to perform the system's function successfully. Plant Protection System(PPS) guarantees the safety of plant by accident detection and control action against the transient conditions of plant. This paper presents the analysis of PPS reliability and the formal problem statement about optimal redundancy based on the reliability of PPS. And the optimization problem is solved by genetic algorithm. The genetic algorithm is a useful tool to solve the problems, in the case of large searching, complex gradient, existence local minimum. The effectiveness of the proposed optimization technique is proved by the target reliability of one channel of PPS, using the failure rate based on the MIL-HDBK-217

  11. Coupling ant colony and the degraded ceiling algorithm for the redundancy allocation problem of series-parallel systems

    International Nuclear Information System (INIS)

    Nahas, Nabil; Nourelfath, Mustapha; Ait-Kadi, Daoud

    2007-01-01

    The redundancy allocation problem (RAP) is a well known NP-hard problem which involves the selection of elements and redundancy levels to maximize system reliability given various system-level constraints. As telecommunications and internet protocol networks, manufacturing and power systems are becoming more and more complex, while requiring short developments schedules and very high reliability, it is becoming increasingly important to develop efficient solutions to the RAP. This paper presents an efficient algorithm to solve this reliability optimization problem. The idea of a heuristic approach design is inspired from the ant colony meta-heuristic optimization method and the degraded ceiling local search technique. Our hybridization of the ant colony meta-heuristic with the degraded ceiling performs well and is competitive with the best-known heuristics for redundancy allocation. Numerical results for the 33 test problems from previous research are reported and compared. The solutions found by our approach are all better than or are in par with the well-known best solutions

  12. Functional redundancy and food web functioning in linuron-exposed ecosystems

    Energy Technology Data Exchange (ETDEWEB)

    De Laender, F., E-mail: frederik.delaender@ugent.be [Laboratory of Environmental Toxicity and Aquatic Ecology, Ghent University, Plateaustraat 22, 9000 Ghent (Belgium); Van den Brink, P.J., E-mail: Paul.vandenBrink@wur.nl [Department of Aquatic Ecology and Water Quality Management, Wageningen University, PO Box 47, 6700 AA Wageningen (Netherlands); Janssen, C.R., E-mail: colin.janssen@ugent.be [Laboratory of Environmental Toxicity and Aquatic Ecology, Ghent University, Plateaustraat 22, 9000 Ghent (Belgium)

    2011-10-15

    An extensive data set describing effects of the herbicide linuron on macrophyte-dominated microcosms was analysed with a food web model to assess effects on ecosystem functioning. We showed that sensitive phytoplankton and periphyton groups in the diets of heterotrophs were gradually replaced by more tolerant phytoplankton species as linuron concentrations increased. This diet shift - showing redundancy among phytoplankton species - allowed heterotrophs to maintain their functions in the contaminated microcosms. On an ecosystem level, total gross primary production was up to hundred times lower in the treated microcosms but the uptake of dissolved organic carbon by bacteria and mixotrophs was less sensitive. Food web efficiency was not consistently lower in the treated microcosms. We conclude that linuron predominantly affected the macrophytes but did not alter the overall functioning of the surrounding planktonic food web. Therefore, a risk assessment that protects macrophyte growth also protects the functioning of macrophyte-dominated microcosms. - Highlights: > Food web modelling reveals the functional response of species and ecosystem to linuron. > Primary production was more sensitive to linuron than bacterial production. > Linuron replaced sensitive phytoplankton by tolerant phytoplankton in heterotrophs' diets. > Linuron did not change the functioning of heterotrophs. - Food web modelling reveals functional redundancy of the planktonic community in microcosms treated with linuron.

  13. Functional redundancy and food web functioning in linuron-exposed ecosystems

    International Nuclear Information System (INIS)

    De Laender, F.; Van den Brink, P.J.; Janssen, C.R.

    2011-01-01

    An extensive data set describing effects of the herbicide linuron on macrophyte-dominated microcosms was analysed with a food web model to assess effects on ecosystem functioning. We showed that sensitive phytoplankton and periphyton groups in the diets of heterotrophs were gradually replaced by more tolerant phytoplankton species as linuron concentrations increased. This diet shift - showing redundancy among phytoplankton species - allowed heterotrophs to maintain their functions in the contaminated microcosms. On an ecosystem level, total gross primary production was up to hundred times lower in the treated microcosms but the uptake of dissolved organic carbon by bacteria and mixotrophs was less sensitive. Food web efficiency was not consistently lower in the treated microcosms. We conclude that linuron predominantly affected the macrophytes but did not alter the overall functioning of the surrounding planktonic food web. Therefore, a risk assessment that protects macrophyte growth also protects the functioning of macrophyte-dominated microcosms. - Highlights: → Food web modelling reveals the functional response of species and ecosystem to linuron. → Primary production was more sensitive to linuron than bacterial production. → Linuron replaced sensitive phytoplankton by tolerant phytoplankton in heterotrophs' diets. → Linuron did not change the functioning of heterotrophs. - Food web modelling reveals functional redundancy of the planktonic community in microcosms treated with linuron.

  14. Incident detection and isolation in drilling using analytical redundancy relations

    DEFF Research Database (Denmark)

    Willersrud, Anders; Blanke, Mogens; Imsland, Lars

    2015-01-01

    must be avoided. This paper employs model-based diagnosis using analytical redundancy relations to obtain residuals which are affected differently by the different incidents. Residuals are found to be non-Gaussian - they follow a multivariate t-distribution - hence, a dedicated generalized likelihood...... measurements available. In the latter case, isolation capability is shown to be reduced to group-wise isolation, but the method would still detect all serious events with the prescribed false alarm probability...

  15. Distributed continuous media streaming - Using redundant hierarchy (RED-Hi) servers

    OpenAIRE

    Shah, Mohammad Ahmed

    2014-01-01

    ABSTRACT: The first part of this thesis provides a survey of continuous media serves, including discussions on streaming protocols, models and techniques. In the second part, a novel distributed media streaming system is introduced. In order to manage the traffic in a fault tolerant and effective manner a hierarchical topology, so called redundant hierarchy (RED-Hi) is used. The proposed system works in three steps, namely, object location, path reservation and object delivery. Simulations ar...

  16. A succession of theories: purging redundancy from disturbance theory.

    Science.gov (United States)

    Pulsford, Stephanie A; Lindenmayer, David B; Driscoll, Don A

    2016-02-01

    The topics of succession and post-disturbance ecosystem recovery have a long and convoluted history. There is extensive redundancy within this body of theory, which has resulted in confusion, and the links among theories have not been adequately drawn. This review aims to distil the unique ideas from the array of theory related to ecosystem change in response to disturbance. This will help to reduce redundancy, and improve communication and understanding between researchers. We first outline the broad range of concepts that have developed over the past century to describe community change in response to disturbance. The body of work spans overlapping succession concepts presented by Clements in 1916, Egler in 1954, and Connell and Slatyer in 1977. Other theories describing community change include state and transition models, biological legacy theory, and the application of functional traits to predict responses to disturbance. Second, we identify areas of overlap of these theories, in addition to highlighting the conceptual and taxonomic limitations of each. In aligning each of these theories with one another, the limited scope and relative inflexibility of some theories becomes apparent, and redundancy becomes explicit. We identify a set of unique concepts to describe the range of mechanisms driving ecosystem responses to disturbance. We present a schematic model of our proposed synthesis which brings together the range of unique mechanisms that were identified in our review. The model describes five main mechanisms of transition away from a post-disturbance community: (i) pulse events with rapid state shifts; (ii) stochastic community drift; (iii) facilitation; (iv) competition; and (v) the influence of the initial composition of a post-disturbance community. In addition, stabilising processes such as biological legacies, inhibition or continuing disturbance may prevent a transition between community types. Integrating these six mechanisms with the functional

  17. Structure, composition and morphology of bioactive titanate layer on porous titanium surfaces

    Science.gov (United States)

    Li, Jinshan; Wang, Xiaohua; Hu, Rui; Kou, Hongchao

    2014-07-01

    A bioactive coating was produced on pore surfaces of porous titanium samples by an amendatory alkali-heat treatment method. Porous titanium was prepared by powder metallurgy and its porosity and average size were 45% and 135 μm, respectively. Coating morphology, coating structure and phase constituents were examined by SEM, XPS and XRD. It was found that a micro-network structure with sizes of cells, and redundant Ca ion was detected in the titanate layer. The concentration distribution of Ti, O, Ca and Na in the coating showed a compositional gradient from the intermediate layer toward the outer surface. These compositional gradients indicate that the coating bonded to Ti substrate without a distinct interface. After immersion into the SBF solution for 3 days, a bone-like carbonate-hydroxylapatite showing a good biocompatibility was detected on the coating surface. And the redundant Ca advanced the bioactivity of the coating. Thus, the present modification is expected to allow the use of the bioactive porous titanium as artificial bones even under load-bearing conditions.

  18. Carrier population control and surface passivation in solar cells

    KAUST Repository

    Cuevas, Andres

    2018-05-02

    Controlling the concentration of charge carriers near the surface is essential for solar cells. It permits to form regions with selective conductivity for either electrons or holes and it also helps to reduce the rate at which they recombine. Chemical passivation of the surfaces is equally important, and it can be combined with population control to implement carrier-selective, passivating contacts for solar cells. This paper discusses different approaches to suppress surface recombination and to manipulate the concentration of carriers by means of doping, work function and charge. It also describes some of the many surface-passivating contacts that are being developed for silicon solar cells, restricted to experiments performed by the authors.

  19. [Relationships between soil and rocky desertification in typical karst mountain area based on redundancy analysis].

    Science.gov (United States)

    Long, Jian; Liao, Hong-Kai; Li, Juan; Chen, Cai-Yun

    2012-06-01

    Redundancy analysis (RDA) was employed to reveal the relationships between soil and rocky desertification through vegetation investigation and analysis of soil samples collected in typical karst mountain area of southwest Guizhou Province. The results showed that except TP, TK and ACa, all other variables including SOC, TN, MBC, ROC, DOC, available nutrients and basal respiration showed significant downward trends during the rocky desertification process. RDA results showed significant correlations between different types of desertification and soil variables, described as non-degraded > potential desertification > light desertification > moderate desertification > severe desertification. Moreover, RDA showed that using SOC, TN, AN, and BD as soil indicators, 74.4% of the variance information on soil and rocky desertification could be explained. Furthermore, the results of correlation analysis showed that soil variables were significantly affected by surface vegetation. Considering the ecological function of the aboveground vegetation and the soil quality, Zanthoxylum would be a good choice for restoration of local vegetation in karst mountain area.

  20. Performance and delay analysis of hybrid ARQ with incremental redundancy over double rayleigh fading channels

    KAUST Repository

    Chelli, Ali

    2014-11-01

    In this paper, we study the performance of hybrid automatic repeat request (HARQ) with incremental redundancy over double Rayleigh channels, a common model for the fading amplitude of vehicle-to-vehicle communication systems. We investigate the performance of HARQ from an information theoretic perspective. Analytical expressions are derived for the \\\\epsilon-outage capacity, the average number of transmissions, and the average transmission rate of HARQ with incremental redundancy assuming a maximum number of HARQ rounds. Moreover, we evaluate the delay experienced by Poisson arriving packets for HARQ with incremental redundancy. We provide analytical expressions for the expected waiting time, the packet\\'s sojourn time in the queue, the average consumed power, and the energy efficiency. In our study, the communication rate per HARQ round is adjusted to the average signal-to-noise ratio (SNR) such that a target outage probability is not exceeded. This setting conforms with communication systems in which a quality of service is expected regardless of the channel conditions. Our analysis underscores the importance of HARQ in improving the spectral efficiency and reliability of communication systems. We demonstrate as well that the explored HARQ scheme achieves full diversity. Additionally, we investigate the tradeoff between energy efficiency and spectral efficiency.

  1. Surface origin and control of resonance Raman scattering and surface band gap in indium nitride

    International Nuclear Information System (INIS)

    Alarcón-Lladó, Esther; Brazzini, Tommaso; Ager, Joel W

    2016-01-01

    Resonance Raman scattering measurements were performed on indium nitride thin films under conditions where the surface electron concentration was controlled by an electrolyte gate. As the surface condition is tuned from electron depletion to accumulation, the spectral feature at the expected position of the ( E 1 , A 1 ) longitudinal optical (LO) near 590 cm −1 shifts to lower frequency. The shift is reversibly controlled with the applied gate potential, which clearly demonstrates the surface origin of this feature. The result is interpreted within the framework of a Martin double resonance, where the surface functions as a planar defect, allowing the scattering of long wavevector phonons. The allowed wavevector range, and hence the frequency, is modulated by the electron accumulation due to band gap narrowing. A surface band gap reduction of over 500 meV is estimated for the conditions of maximum electron accumulation. Under conditions of electron depletion, the full InN bandgap ( E g   =  0.65 eV) is expected at the surface. The drastic change in the surface band gap is expected to influence the transport properties of devices which utilize the surface electron accumulation layer. (paper)

  2. Surface origin and control of resonance Raman scattering and surface band gap in indium nitride

    Science.gov (United States)

    Alarcón-Lladó, Esther; Brazzini, Tommaso; Ager, Joel W.

    2016-06-01

    Resonance Raman scattering measurements were performed on indium nitride thin films under conditions where the surface electron concentration was controlled by an electrolyte gate. As the surface condition is tuned from electron depletion to accumulation, the spectral feature at the expected position of the (E 1, A 1) longitudinal optical (LO) near 590 cm-1 shifts to lower frequency. The shift is reversibly controlled with the applied gate potential, which clearly demonstrates the surface origin of this feature. The result is interpreted within the framework of a Martin double resonance, where the surface functions as a planar defect, allowing the scattering of long wavevector phonons. The allowed wavevector range, and hence the frequency, is modulated by the electron accumulation due to band gap narrowing. A surface band gap reduction of over 500 meV is estimated for the conditions of maximum electron accumulation. Under conditions of electron depletion, the full InN bandgap (E g  =  0.65 eV) is expected at the surface. The drastic change in the surface band gap is expected to influence the transport properties of devices which utilize the surface electron accumulation layer.

  3. Minimization of the Electromagnetic Torque Ripple Caused by the Coils Inter-Turn Short Circuit Fault in Dual-Redundancy Permanent Magnet Synchronous Motors

    Directory of Open Access Journals (Sweden)

    Yiguang Chen

    2017-11-01

    Full Text Available With the development of electric vehicles and More-Electric/All-Electric aircraft, high reliability is required in motor servo systems. The redundancy technique is one of the most effective methods to improve the reliability of motor servo systems. In this paper, the structure of dual-redundancy permanent magnet synchronous motor (DRPMSM with weak thermal coupling and no electromagnetic coupling is analyzed and the mathematical model of this motor is established. However, there is little research on how to suppress the torque ripple caused by short-circuited coils in the DRPMSM. The main contribution of this paper is to present the advantages of DRPMSM and to find a way to suppress the torque ripple caused by the short circuit fault in DRPMSM. In order to improve operation quality and enhance the reliability of DRPMSM after a short circuit occurs, the torque ripple caused by the coils inter-turn short circuit fault in DRPMSM is analyzed in detail. Then, a control method for suppressing the electromagnetic torque ripple of a short-circuited coil is proposed for the first time by using an improved adaptive proportional resonant (PR controller and a proportional integral (PI controller in parallel. PR control is a method of controlling alternating components without steady-state error, and it can be used to suppress torque ripple. DRPMSM adopts speed and current double closed-loop control strategies. An improved adaptive PR controller and a PI controller are employed in parallel for the speed loop, while traditional PI control is adopted in current loop. From the simulation and experimental results, the torque ripple is reduced from 45.4 to 5.6% when the torque ripple suppression strategy proposed in this paper is adopted, in the case that the speed is 600 r/min. The torque ripple suppression strategy based on the PR controller can quickly and effectively suppress the torque ripple caused by the short-circuited coils, which makes the motor speed

  4. Adaptive Dynamic Surface Control for Generator Excitation Control System

    Directory of Open Access Journals (Sweden)

    Zhang Xiu-yu

    2014-01-01

    Full Text Available For the generator excitation control system which is equipped with static var compensator (SVC and unknown parameters, a novel adaptive dynamic surface control scheme is proposed based on neural network and tracking error transformed function with the following features: (1 the transformation of the excitation generator model to the linear systems is omitted; (2 the prespecified performance of the tracking error can be guaranteed by combining with the tracking error transformed function; (3 the computational burden is greatly reduced by estimating the norm of the weighted vector of neural network instead of the weighted vector itself; therefore, it is more suitable for the real time control; and (4 the explosion of complicity problem inherent in the backstepping control can be eliminated. It is proved that the new scheme can make the system semiglobally uniformly ultimately bounded. Simulation results show the effectiveness of this control scheme.

  5. Functional redundancy and complementarities of seed dispersal by the last neotropical megafrugivores.

    Science.gov (United States)

    Bueno, Rafael S; Guevara, Roger; Ribeiro, Milton C; Culot, Laurence; Bufalo, Felipe S; Galetti, Mauro

    2013-01-01

    Functional redundancy has been debated largely in ecology and conservation, yet we lack detailed empirical studies on the roles of functionally similar species in ecosystem function. Large bodied frugivores may disperse similar plant species and have strong impact on plant recruitment in tropical forests. The two largest frugivores in the neotropics, tapirs (Tapirus terrestris) and muriquis (Brachyteles arachnoides) are potential candidates for functional redundancy on seed dispersal effectiveness. Here we provide a comparison of the quantitative, qualitative and spatial effects on seed dispersal by these megafrugivores in a continuous Brazilian Atlantic forest. We found a low overlap of plant species dispersed by both muriquis and tapirs. A group of 35 muriquis occupied an area of 850 ha and dispersed 5 times more plant species, and 13 times more seeds than 22 tapirs living in the same area. Muriquis dispersed 2.4 times more seeds in any random position than tapirs. This can be explained mainly because seed deposition by muriquis leaves less empty space than tapirs. However, tapirs are able to disperse larger seeds than muriquis and move them into sites not reached by primates, such as large forest gaps, open areas and fragments nearby. Based on published information we found 302 plant species that are dispersed by at least one of these megafrugivores in the Brazilian Atlantic forest. Our study showed that both megafrugivores play complementary rather than redundant roles as seed dispersers. Although tapirs disperse fewer seeds and species than muriquis, they disperse larger-seeded species and in places not used by primates. The selective extinction of these megafrugivores will change the spatial seed rain they generate and may have negative effects on the recruitment of several plant species, particularly those with large seeds that have muriquis and tapirs as the last living seed dispersers.

  6. Functional Redundancy and Complementarities of Seed Dispersal by the Last Neotropical Megafrugivores

    Science.gov (United States)

    Bueno, Rafael S.; Guevara, Roger; Ribeiro, Milton C.; Culot, Laurence; Bufalo, Felipe S.; Galetti, Mauro

    2013-01-01

    Background Functional redundancy has been debated largely in ecology and conservation, yet we lack detailed empirical studies on the roles of functionally similar species in ecosystem function. Large bodied frugivores may disperse similar plant species and have strong impact on plant recruitment in tropical forests. The two largest frugivores in the neotropics, tapirs (Tapirus terrestris) and muriquis (Brachyteles arachnoides) are potential candidates for functional redundancy on seed dispersal effectiveness. Here we provide a comparison of the quantitative, qualitative and spatial effects on seed dispersal by these megafrugivores in a continuous Brazilian Atlantic forest. Methodology/Principal Findings We found a low overlap of plant species dispersed by both muriquis and tapirs. A group of 35 muriquis occupied an area of 850 ha and dispersed 5 times more plant species, and 13 times more seeds than 22 tapirs living in the same area. Muriquis dispersed 2.4 times more seeds in any random position than tapirs. This can be explained mainly because seed deposition by muriquis leaves less empty space than tapirs. However, tapirs are able to disperse larger seeds than muriquis and move them into sites not reached by primates, such as large forest gaps, open areas and fragments nearby. Based on published information we found 302 plant species that are dispersed by at least one of these megafrugivores in the Brazilian Atlantic forest. Conclusions/Significance Our study showed that both megafrugivores play complementary rather than redundant roles as seed dispersers. Although tapirs disperse fewer seeds and species than muriquis, they disperse larger-seeded species and in places not used by primates. The selective extinction of these megafrugivores will change the spatial seed rain they generate and may have negative effects on the recruitment of several plant species, particularly those with large seeds that have muriquis and tapirs as the last living seed dispersers. PMID

  7. Functional redundancy and complementarities of seed dispersal by the last neotropical megafrugivores.

    Directory of Open Access Journals (Sweden)

    Rafael S Bueno

    Full Text Available Functional redundancy has been debated largely in ecology and conservation, yet we lack detailed empirical studies on the roles of functionally similar species in ecosystem function. Large bodied frugivores may disperse similar plant species and have strong impact on plant recruitment in tropical forests. The two largest frugivores in the neotropics, tapirs (Tapirus terrestris and muriquis (Brachyteles arachnoides are potential candidates for functional redundancy on seed dispersal effectiveness. Here we provide a comparison of the quantitative, qualitative and spatial effects on seed dispersal by these megafrugivores in a continuous Brazilian Atlantic forest.We found a low overlap of plant species dispersed by both muriquis and tapirs. A group of 35 muriquis occupied an area of 850 ha and dispersed 5 times more plant species, and 13 times more seeds than 22 tapirs living in the same area. Muriquis dispersed 2.4 times more seeds in any random position than tapirs. This can be explained mainly because seed deposition by muriquis leaves less empty space than tapirs. However, tapirs are able to disperse larger seeds than muriquis and move them into sites not reached by primates, such as large forest gaps, open areas and fragments nearby. Based on published information we found 302 plant species that are dispersed by at least one of these megafrugivores in the Brazilian Atlantic forest.Our study showed that both megafrugivores play complementary rather than redundant roles as seed dispersers. Although tapirs disperse fewer seeds and species than muriquis, they disperse larger-seeded species and in places not used by primates. The selective extinction of these megafrugivores will change the spatial seed rain they generate and may have negative effects on the recruitment of several plant species, particularly those with large seeds that have muriquis and tapirs as the last living seed dispersers.

  8. Polarization-controlled asymmetric excitation of surface plasmons

    KAUST Repository

    Xu, Quan

    2017-08-28

    Free-space light can be coupled into propagating surface waves at a metal–dielectric interface, known as surface plasmons (SPs). This process has traditionally faced challenges in preserving the incident polarization information and controlling the directionality of the excited SPs. The recently reported polarization-controlled asymmetric excitation of SPs in metasurfaces has attracted much attention for its promise in developing innovative plasmonic devices. However, the unit elements in these works were purposely designed in certain orthogonal polarizations, i.e., linear or circular polarizations, resulting in limited two-level polarization controllability. Here, we introduce a coupled-mode theory to overcome this limit. We demonstrated theoretically and experimentally that, by utilizing the coupling effect between a pair of split-ring-shaped slit resonators, exotic asymmetric excitation of SPs can be obtained under the x-, y-, left-handed circular, and right-handed circular polarization incidences, while the polarization information of the incident light can be preserved in the excited SPs. The versatility of the presented design scheme would offer opportunities for polarization sensing and polarization-controlled plasmonic devices.

  9. Unified performance analysis of hybrid-ARQ with incremental redundancy over free-space optical channels

    KAUST Repository

    Zedini, Emna; Chelli, Ali; Alouini, Mohamed-Slim

    2014-01-01

    In this paper, we carry out a unified performance analysis of hybrid automatic repeat request (HARQ) with incremental redundancy (IR) from an information theoretic perspective over a point-to-point free-space optical (FSO) system. First, we

  10. Neutron radiography of aircraft composite flight control surfaces

    International Nuclear Information System (INIS)

    Lewis, W.J.; Bennett, L.G.I.; Chalovich, T.R.; Francescone, O.

    2001-01-01

    A small (20 kWth), safe, pool-type nuclear research reactor called the SLOWPOKE-2 is located at the Royal Military College of Canada (RMC). The reactor was originally installed for teaching, training, research and semi-routine analysis, specifically, neutron activation analysis. It was envisioned that the neutrons from the SLOWPOKE-2 could also be used for neutron radiography, and so a research program was initiated to develop this technology. Over a period of approximately 15 years, and through a series of successive modifications, a neutron radiography system (NRS) was developed. Once completed, several applications of the technology have been demonstrated, including the nondestructive examination of the composite flight control surfaces from the Canadian Air Force's primary jet fighter, the CF18 Hornet aircraft. An initial trial was setup to investigate the flight control surfaces of 3 aircraft, to determine the parameters for a final licensed system, and to compare the results to other nondestructive methods. Over 500 neutron radiographs were made for these first 3 aircraft, and moisture and corrosion were discovered in the honeycomb structure and hydration was found in the composite and adhesive layers. In comparison with other NDT methods, neutron radiography was the only method that could detect the small areas of corrosion and moisture entrapment. However, before examining an additional 7 aircraft, the recommended modifications to the NRS were undertaken. These modifications were necessary to accommodate the larger flight control surfaces safely by incorporating flexible conformable shielding. As well, to expedite inspections so that all flight control surfaces from one aircraft could be completed in less than two weeks, there was a need to decrease the exposure time by both faster film/conversion screen combinations and by incorporating the capability of near realtime, digital radioscopy. Finally, as there are no inspection specific image quality

  11. Developmental Changes in Children’s Processing of Redundant Modifiers in Definite Object Descriptions

    NARCIS (Netherlands)

    Koolen, Ruud; Krahmer, Emiel; Swerts, Marc

    2016-01-01

    This paper investigates developmental changes in children’s processing of redundant information in definite object descriptions. In two experiments, children of two age groups (6 or 7, and 9 or 10 years old) were presented with pictures of sweets. In the first experiment (pairwise comparison), two

  12. A heuristic for solving the redundancy allocation problem for multi-state series-parallel systems

    International Nuclear Information System (INIS)

    Ramirez-Marquez, Jose E.; Coit, David W.

    2004-01-01

    The redundancy allocation problem is formulated with the objective of minimizing design cost, when the system exhibits a multi-state reliability behavior, given system-level performance constraints. When the multi-state nature of the system is considered, traditional solution methodologies are no longer valid. This study considers a multi-state series-parallel system (MSPS) with capacitated binary components that can provide different multi-state system performance levels. The different demand levels, which must be supplied during the system-operating period, result in the multi-state nature of the system. The new solution methodology offers several distinct benefits compared to traditional formulations of the MSPS redundancy allocation problem. For some systems, recognizing that different component versions yield different system performance is critical so that the overall system reliability estimation and associated design models the true system reliability behavior more realistically. The MSPS design problem, solved in this study, has been previously analyzed using genetic algorithms (GAs) and the universal generating function. The specific problem being addressed is one where there are multiple component choices, but once a component selection is made, only the same component type can be used to provide redundancy. This is the first time that the MSPS design problem has been addressed without using GAs. The heuristic offers more efficient and straightforward analyses. Solutions to three different problem types are obtained illustrating the simplicity and ease of application of the heuristic without compromising the intended optimization needs

  13. Biomedical devices engineered based on the control of the surface wettability

    OpenAIRE

    Oliveira, Nuno Miguel Ribeiro de

    2017-01-01

    Tese de Doutoramento em Engenharia de Tecidos, Medicina Regenerativa e Células Estaminais The wettability control has been showed as an important parameter for several systems and applications on the biomedical field. Once the surface wettability has crucial influence in protein adsorption and cell adhesion. Here, the focus was on the technology development based on the advanced control of wettability in surfaces, tuning directly the surface characteristics or modifying surface...

  14. False targets vs. redundancy in homogeneous parallel systems

    International Nuclear Information System (INIS)

    Levitin, Gregory; Hausken, Kjell

    2009-01-01

    System defense against natural threats and disasters that have a stochastic nature includes providing redundancy and protecting system elements. The defense against strategic intentional attacks can also include deploying false targets aimed at misleading the attacker. Distribution of the available resources among different defensive means is an important problem that arises in organizing the defense of complex civil infrastructures, industrial systems or military objects. The article considers defense resource allocation in a system exposed to external intentional attack. The expected damage caused by the attack is evaluated as system unsupplied demand. The defender distributes its limited resource between deploying redundant genuine elements and false elements, both of which are targets of attack. The attacker attacks a subset of the elements and distributes its limited resource evenly among the attacked elements. Two cases are considered: in the first one the number of attacked elements and the vulnerability of each genuine element are fixed and the defense resource distribution is determined as a solution of an optimization problem; in the second one the number of attacked elements is the attacker's free choice variable and the element's vulnerability depends on a contest determined by the defender's and attacker's resources allocated to each element. The defender's optimal resource distribution strategy is determined as a solution of a two-period minmax game. It is shown that the optimal number of genuine elements decreases monotonically with the growth of the element cost and vulnerability, whereas the optimal number of false elements demonstrates non-monotonic behavior. The contest intensity is an important factor influencing the optimal defense resource distribution. It cannot be ignored when the defense strategy is determined, and it thus also impacts the attack strategy

  15. Verification of Triple Modular Redundancy Insertion for Reliable and Trusted Systems

    Science.gov (United States)

    Berg, Melanie; LaBel, Kenneth

    2016-01-01

    If a system is required to be protected using triple modular redundancy (TMR), improper insertion can jeopardize the reliability and security of the system. Due to the complexity of the verification process and the complexity of digital designs, there are currently no available techniques that can provide complete and reliable confirmation of TMR insertion. We propose a method for TMR insertion verification that satisfies the process for reliable and trusted systems.

  16. Redundant filtration system of the fuel buildings,units 1 and 2 Almaraz NPP

    International Nuclear Information System (INIS)

    Lopez Tanco, J.

    2011-01-01

    The project redundant filtering fuel buildings in units 1 and 2 of Almaraz NPP, will compliance to the requirements established in the complementary technical instructions to the authorization of exploitation of Almaraz NPP, established by the CSN and will consist of the installation of a new filtration unit.

  17. Time efficient signed Vedic multiplier using redundant binary representation

    Directory of Open Access Journals (Sweden)

    Ranjan Kumar Barik

    2017-03-01

    Full Text Available This study presents a high-speed signed Vedic multiplier (SVM architecture using redundant binary (RB representation in Urdhva Tiryagbhyam (UT sutra. This is the first ever effort towards extension of Vedic algorithms to the signed numbers. The proposed multiplier architecture solves the carry propagation issue in UT sutra, as carry free addition is possible in RB representation. The proposed design is coded in VHDL and synthesised in Xilinx ISE 14.4 of various FPGA devices. The proposed SVM architecture has better speed performances as compared with various state-of-the-art conventional as well as Vedic architectures.

  18. A case for Redundant Arrays of Inexpensive Disks (RAID)

    Science.gov (United States)

    Patterson, David A.; Gibson, Garth; Katz, Randy H.

    1988-01-01

    Increasing performance of CPUs and memories will be squandered if not matched by a similar performance increase in I/O. While the capacity of Single Large Expensive Disks (SLED) has grown rapidly, the performance improvement of SLED has been modest. Redundant Arrays of Inexpensive Disks (RAID), based on the magnetic disk technology developed for personal computers, offers an attractive alternative to SLED, promising improvements of an order of magnitude in performance, reliability, power consumption, and scalability. This paper introduces five levels of RAIDs, giving their relative cost/performance, and compares RAID to an IBM 3380 and a Fujitsu Super Eagle.

  19. Redundant imprinting of information in nonideal environments: Objective reality via a noisy channel

    International Nuclear Information System (INIS)

    Zwolak, Michael; Quan, H. T.; Zurek, Wojciech H.

    2010-01-01

    Quantum Darwinism provides an information-theoretic framework for the emergence of the objective, classical world from the quantum substrate. The key to this emergence is the proliferation of redundant information throughout the environment where observers can then intercept it. We study this process for a purely decohering interaction when the environment, E, is in a nonideal (e.g., mixed) initial state. In the case of good decoherence, that is, after the pointer states have been unambiguously selected, the mutual information between the system, S, and an environment fragment, F, is given solely by F's entropy increase. This demonstrates that the environment's capacity for recording the state of S is directly related to its ability to increase its entropy. Environments that remain nearly invariant under the interaction with S, either because they have a large initial entropy or a misaligned initial state, therefore have a diminished ability to acquire information. To elucidate the concept of good decoherence, we show that, when decoherence is not complete, the deviation of the mutual information from F's entropy change is quantified by the quantum discord, i.e., the excess mutual information between S and F is information regarding the initial coherence between pointer states of S. In addition to illustrating these results with a single-qubit system interacting with a multiqubit environment, we find scaling relations for the redundancy of information acquired by the environment that display a universal behavior independent of the initial state of S. Our results demonstrate that Quantum Darwinism is robust with respect to nonideal initial states of the environment: the environment almost always acquires redundant information about the system but its rate of acquisition can be reduced.

  20. Pigeons learn stimulus identity and stimulus relations when both serve as redundant, relevant cues during same-different discrimination training.

    Science.gov (United States)

    Gibson, Brett M; Wasserman, Edward A

    2003-01-01

    The authors taught pigeons to discriminate displays of 16 identical items from displays of 16 nonidentical items. Unlike most same-different discrimination studies--where only stimulus relations could serve a discriminative function--both the identity of the items and the relations among the items were discriminative features of the displays. The pigeons learned about both stimulus identity and stimulus relations when these 2 sources of information served as redundant, relevant cues. In tests of associative competition, identity cues exerted greater stimulus control than relational cues. These results suggest that the pigeon can respond to both specific stimuli and general relations in the environment.

  1. Towards self-tuning residual generators for UAV control surface fault diagnosis

    DEFF Research Database (Denmark)

    Blanke, Mogens; Hansen, Søren

    2013-01-01

    Control surface fault diagnosis is essential for timely detection of manoeuvring and stability risks for an unmanned aircraft. Timely detection is crucial since control surface related faults impact stability of flight and safety. Reliable diagnosis require well fitting dynamical models but with ...... flights with different members of a population of UAVs that have inherent model uncertainty from one member to another and from one flight to another. Events with actual faults on control surfaces demonstrates the efficacy of the approach....

  2. Evaluation of clinical curative effects of disposable stitching instrument in redundant prepuce patients

    Science.gov (United States)

    Wang, Haitao; Chen, Ningjie; Huo, Ran; Yang, Jincun; Li, Xia; Xing, Nan

    2017-01-01

    The present study aimed to investigate the clinical curative effect of disposable stitching instrument operation in patients with redundant prepuce or phimosis. A total of 102 cases of patients with circumcision were randomly selected (from June 2013 to December 2014) from the department of plastic and aesthetic surgery of our hospital and were randomly divided into control and observation groups (n=51). Patients in the control group were treated by traditional circumcision operation, while patients in the observation group were treated by novel disposable circumcision stitching instrument. Operation time, bleeding volume, incision healing time, postoperative complications and incision aesthetic satisfaction in the groups were observed. As a result, intraoperative bleeding volume of patients in the observation group was significantly less in comparison to the control group. Operation time and incision healing time of patients in the observation group was shorter than that of the control group. Additionally, the incidence of postoperative complications of patients in the observation group was noted to be lower than that of the control group. On the other hand, the incision aesthetic satisfaction of patients in the observation group was higher than that of the control group. Blood vessel counting and nerve fiber counting of tissue specimen in the observation group were more than those of the control group. Postoperative VAS scores of patients in the observation group were significantly lower than that of the control group. Each rating scale scores of EPQ of patients in the observation group improved significantly compared with that of the control group. In conclusion, the present findings show that disposable circumcision stitching instrument operation is more advantageous in comparison to the traditional procedure along with minimal compilations and better post surgery health condition of patients. PMID:28672929

  3. Ride control of surface effect ships using distributed control

    Directory of Open Access Journals (Sweden)

    Asgeir J. Sørensen

    1994-04-01

    Full Text Available A ride control system for active damping of heave and pitch accelerations of Surface Effect Ships (SES is presented. It is demonstrated that distributed effects that are due to a spatially varying pressure in the air cushion result in significant vertical vibrations in low and moderate sea states. In order to achieve a high quality human comfort and crew workability it is necessary to reduce these vibrations using a control system which accounts for distributed effects due to spatial pressure variations in the air cushion. A mathematical model of the process is presented, and collocated sensor and actuator pairs are used. The process stability is ensured using a controller with appropriate passivity properties. Sensor and actuator location is also discussed. The performance of the ride control system is shown by power spectra of the vertical accelerations obtained from full scale experiments with a 35 m SES.

  4. Ambiguity attacks on robust blind image watermarking scheme based on redundant discrete wavelet transform and singular value decomposition

    Directory of Open Access Journals (Sweden)

    Khaled Loukhaoukha

    2017-12-01

    Full Text Available Among emergent applications of digital watermarking are copyright protection and proof of ownership. Recently, Makbol and Khoo (2013 have proposed for these applications a new robust blind image watermarking scheme based on the redundant discrete wavelet transform (RDWT and the singular value decomposition (SVD. In this paper, we present two ambiguity attacks on this algorithm that have shown that this algorithm fails when used to provide robustness applications like owner identification, proof of ownership, and transaction tracking. Keywords: Ambiguity attack, Image watermarking, Singular value decomposition, Redundant discrete wavelet transform

  5. Wireless sensing and vibration control with increased redundancy and robustness design.

    Science.gov (United States)

    Li, Peng; Li, Luyu; Song, Gangbing; Yu, Yan

    2014-11-01

    Control systems with long distance sensor and actuator wiring have the problem of high system cost and increased sensor noise. Wireless sensor network (WSN)-based control systems are an alternative solution involving lower setup and maintenance costs and reduced sensor noise. However, WSN-based control systems also encounter problems such as possible data loss, irregular sampling periods (due to the uncertainty of the wireless channel), and the possibility of sensor breakdown (due to the increased complexity of the overall control system). In this paper, a wireless microcontroller-based control system is designed and implemented to wirelessly perform vibration control. The wireless microcontroller-based system is quite different from regular control systems due to its limited speed and computational power. Hardware, software, and control algorithm design are described in detail to demonstrate this prototype. Model and system state compensation is used in the wireless control system to solve the problems of data loss and sensor breakdown. A positive position feedback controller is used as the control law for the task of active vibration suppression. Both wired and wireless controllers are implemented. The results show that the WSN-based control system can be successfully used to suppress the vibration and produces resilient results in the presence of sensor failure.

  6. Upgrade of the Los Alamos Plutonium Facility control system

    International Nuclear Information System (INIS)

    Pope, N.G.; Turner, W.J.; Brown, R.E.; Bibeau, R.A.; Davis, R.R.; Hogan, K.

    1996-01-01

    After 20 yrs service, the Los Alamos Plutonium Facility is undergoing an upgrade to its aging Facility Control System. The new system design includes a network of redundantly-paired programmable logic controllers that will interface with about 2200 field data points. The data communications network that has been designed includes a redundant, self-healing fiber optic data highway as well as a fiber optic ethernet. Commercially available human-machine interface software running on a UNIX-based system displays facility subsystem status operator X-terminals. Project design features, methods, costs, and schedule are discussed

  7. Development of high-reliability control system for nuclear power plants

    International Nuclear Information System (INIS)

    Asami, K.; Yanai, K.; Hirose, H.; Ito, T.

    1983-01-01

    In Japan, many nuclear power generating plants are in operation and under construction. There is a general awareness of the problems in connection with nuclear power generation and strong emphasis is put on achieving highly reliable operation of nuclear power plants. Hitachi has developed a new high-reliability control system. NURECS-3000 (NUclear Power Plant High-REliability Control System), which is applied to the main control systems, such as the reactor feedwater control system, the reactor recirculation control system and the main turbine control system. The NURECS-3000 system was designed taking into account the fact that there will be failures, but the aim is for the system to continue to function correctly; it is therefore a fault-tolerant system. It has redundant components which can be completely isolated from each other in order to prevent fault propagation. The system has a hierarchical configuration, with a main controller, consisting of a triplex microcomputer system, and sub-loop controllers. Special care was taken to ensure the independence of these subsystems. Since most of the redundant system failures are caused by common-mode failures and the reliability of redundant systems depends on the reliability of the common-mode parts, the aim was to minimize these parts. (author)

  8. Converging Redundant Sensor Network Information for Improved Building Control

    Energy Technology Data Exchange (ETDEWEB)

    Dale Tiller; D. Phil; Gregor Henze; Xin Guo

    2007-09-30

    This project investigated the development and application of sensor networks to enhance building energy management and security. Commercial, industrial and residential buildings often incorporate systems used to determine occupancy, but current sensor technology and control algorithms limit the effectiveness of these systems. For example, most of these systems rely on single monitoring points to detect occupancy, when more than one monitoring point could improve system performance. Phase I of the project focused on instrumentation and data collection. During the initial project phase, a new occupancy detection system was developed, commissioned and installed in a sample of private offices and open-plan office workstations. Data acquisition systems were developed and deployed to collect data on space occupancy profiles. Phase II of the project demonstrated that a network of several sensors provides a more accurate measure of occupancy than is possible using systems based on single monitoring points. This phase also established that analysis algorithms could be applied to the sensor network data stream to improve the accuracy of system performance in energy management and security applications. In Phase III of the project, the sensor network from Phase I was complemented by a control strategy developed based on the results from the first two project phases: this controller was implemented in a small sample of work areas, and applied to lighting control. Two additional technologies were developed in the course of completing the project. A prototype web-based display that portrays the current status of each detector in a sensor network monitoring building occupancy was designed and implemented. A new capability that enables occupancy sensors in a sensor network to dynamically set the 'time delay' interval based on ongoing occupant behavior in the space was also designed and implemented.

  9. Electronically controllable spoof localized surface plasmons

    Science.gov (United States)

    Zhou, Yong Jin; Zhang, Chao; Yang, Liu; Xun Xiao, Qian

    2017-10-01

    Electronically controllable multipolar spoof localized surface plasmons (LSPs) are experimentally demonstrated in the microwave frequencies. It has been shown that half integer order LSPs modes exist on the corrugated ring loaded with a slit, which actually arise from the Fabry-Perot-like resonances. By mounting active components across the slit in the corrugated rings, electronic switchability and tunability of spoof LSPs modes have been accomplished. Both simulated and measured results demonstrate efficient dynamic control of the spoof LSPs. These elements may form the basis of highly integrated programmable plasmonic circuits in microwave and terahertz regimes.

  10. Uncertain multiobjective redundancy allocation problem of repairable systems based on artificial bee colony algorithm

    Institute of Scientific and Technical Information of China (English)

    Guo Jiansheng; Wang Zutong; Zheng Mingfa; Wang Ying

    2014-01-01

    Based on the uncertainty theory, this paper is devoted to the redundancy allocation problem in repairable parallel-series systems with uncertain factors, where the failure rate, repair rate and other relative coefficients involved are considered as uncertain variables. The availability of the system and the corresponding designing cost are considered as two optimization objectives. A crisp multiobjective optimization formulation is presented on the basis of uncertainty theory to solve this resultant problem. For solving this problem efficiently, a new multiobjective artificial bee colony algorithm is proposed to search the Pareto efficient set, which introduces rank value and crowding distance in the greedy selection strategy, applies fast non-dominated sort procedure in the exploitation search and inserts tournament selection in the onlooker bee phase. It shows that the proposed algorithm outperforms NSGA-II greatly and can solve multiobjective redundancy allocation problem efficiently. Finally, a numerical example is provided to illustrate this approach.

  11. Redundant imprinting of information in non-ideal environments: Quantum Darwinism via a noisy channel

    Science.gov (United States)

    Zwolak, Michael; Quan, Haitao; Zurek, Wojciech

    2011-03-01

    Quantum Darwinism provides an information-theoretic framework for the emergence of the classical world from the quantum substrate. It recognizes that we - the observers - acquire our information about the ``systems of interest'' indirectly from their imprints on the environment. Objectivity, a key property of the classical world, arises via the proliferation of redundant information into the environment where many observers can then intercept it and independently determine the state of the system. While causing a system to decohere, environments that remain nearly invariant under the Hamiltonian dynamics, such as very mixed states, have a diminished ability to transmit information about the system, yet can still acquire redundant information about the system [1,2]. Our results show that Quantum Darwinism is robust with respect to non-ideal initial states of the environment. This research is supported by the U.S. Department of Energy through the LANL/LDRD Program.

  12. Electrospinning onto Insulating Substrates by Controlling Surface Wettability and Humidity

    Science.gov (United States)

    Choi, WooSeok; Kim, Geon Hwee; Shin, Jung Hwal; Lim, Geunbae; An, Taechang

    2017-11-01

    We report a simple method for electrospinning polymers onto flexible, insulating substrates by controlling the wettability of the substrate surface. Water molecules were adsorbed onto the surface of a hydrophilic polymer substrate by increasing the local humidity around the substrate. The adsorbed water was used as the ground electrode for electrospinning. The electrospun fibers were deposited only onto hydrophilic areas of the substrate, allowing for patterning through wettability control. Direct writing of polymer fiber was also possible through near-field electrospinning onto a hydrophilic surface.

  13. Developmental and environmental regulation of Aquaporin gene expression across Populus species: divergence or redundancy?

    Science.gov (United States)

    Cohen, David; Bogeat-Triboulot, Marie-Béatrice; Vialet-Chabrand, Silvère; Merret, Rémy; Courty, Pierre-Emmanuel; Moretti, Sébastien; Bizet, François; Guilliot, Agnès; Hummel, Irène

    2013-01-01

    Aquaporins (AQPs) are membrane channels belonging to the major intrinsic proteins family and are known for their ability to facilitate water movement. While in Populus trichocarpa, AQP proteins form a large family encompassing fifty-five genes, most of the experimental work focused on a few genes or subfamilies. The current work was undertaken to develop a comprehensive picture of the whole AQP gene family in Populus species by delineating gene expression domain and distinguishing responsiveness to developmental and environmental cues. Since duplication events amplified the poplar AQP family, we addressed the question of expression redundancy between gene duplicates. On these purposes, we carried a meta-analysis of all publicly available Affymetrix experiments. Our in-silico strategy controlled for previously identified biases in cross-species transcriptomics, a necessary step for any comparative transcriptomics based on multispecies design chips. Three poplar AQPs were not supported by any expression data, even in a large collection of situations (abiotic and biotic constraints, temporal oscillations and mutants). The expression of 11 AQPs was never or poorly regulated whatever the wideness of their expression domain and their expression level. Our work highlighted that PtTIP1;4 was the most responsive gene of the AQP family. A high functional divergence between gene duplicates was detected across species and in response to tested cues, except for the root-expressed PtTIP2;3/PtTIP2;4 pair exhibiting 80% convergent responses. Our meta-analysis assessed key features of aquaporin expression which had remained hidden in single experiments, such as expression wideness, response specificity and genotype and environment interactions. By consolidating expression profiles using independent experimental series, we showed that the large expansion of AQP family in poplar was accompanied with a strong divergence of gene expression, even if some cases of functional redundancy

  14. Developmental and environmental regulation of Aquaporin gene expression across Populus species: divergence or redundancy?

    Directory of Open Access Journals (Sweden)

    David Cohen

    Full Text Available Aquaporins (AQPs are membrane channels belonging to the major intrinsic proteins family and are known for their ability to facilitate water movement. While in Populus trichocarpa, AQP proteins form a large family encompassing fifty-five genes, most of the experimental work focused on a few genes or subfamilies. The current work was undertaken to develop a comprehensive picture of the whole AQP gene family in Populus species by delineating gene expression domain and distinguishing responsiveness to developmental and environmental cues. Since duplication events amplified the poplar AQP family, we addressed the question of expression redundancy between gene duplicates. On these purposes, we carried a meta-analysis of all publicly available Affymetrix experiments. Our in-silico strategy controlled for previously identified biases in cross-species transcriptomics, a necessary step for any comparative transcriptomics based on multispecies design chips. Three poplar AQPs were not supported by any expression data, even in a large collection of situations (abiotic and biotic constraints, temporal oscillations and mutants. The expression of 11 AQPs was never or poorly regulated whatever the wideness of their expression domain and their expression level. Our work highlighted that PtTIP1;4 was the most responsive gene of the AQP family. A high functional divergence between gene duplicates was detected across species and in response to tested cues, except for the root-expressed PtTIP2;3/PtTIP2;4 pair exhibiting 80% convergent responses. Our meta-analysis assessed key features of aquaporin expression which had remained hidden in single experiments, such as expression wideness, response specificity and genotype and environment interactions. By consolidating expression profiles using independent experimental series, we showed that the large expansion of AQP family in poplar was accompanied with a strong divergence of gene expression, even if some cases of

  15. The application of redundancy-related basic safety principles to the 1400 MWE reactor core standby cooling system

    International Nuclear Information System (INIS)

    Bertrand, R.

    1990-01-01

    This memorandum shall provide the background for the work of the European Community Commission which is to analyze safety principles relating to redundancy. The redundancy-related basic safety principles applied in French nuclear power plants are the following: . the single-failure criterion, . provisions additional to application of the single-failure criterion. These are mainly provisions made at the design stage to minimize risks associated with common cause failures or the risks of human error which can lead to such failures: - protection against hazards of internal and external origin, - the geographical or physical separation of equipment, - the independence of electrical power supplies and distribution systems, - the additional resources and associated operating procedures making it possible to accommodate total loss of the safety systems. The scope also includes the operating rules which ensure availability of redundant safety-related equipment. The provisions relating to the single-failure criterion are detailed in Basic Safety Rule 1.3.A appended. The application of these principles proposed by the operating organization and accepted by the safety authorities for the design and operation of the standby core cooling system (System RIS) is explained

  16. Bond-selective control of a gas-surface reaction

    Science.gov (United States)

    Killelea, Daniel R.

    The prospect of using light to selectively control chemical reactions has tantalized chemists since the development of the laser. Unfortunately, the realization of laser-directed chemistry is frequently thwarted by the randomization of energy within the molecule through intramolecular vibrational energy distribution (IVR). However, recent results showing vibrational mode-specific reactivity on metal surfaces suggest that IVR may not always be complete for gas-surface reactions. Here, we combine molecular beam techniques and direct laser excitation to characterize the bond-specific reactivity of trideuteromethane on a Ni(111) surface. Our results reveal important details about how vibrational energy is distributed in the reactive molecule. We use a molecular beam to direct state-selected trideuteromethane (CHD 3) molecules onto a nickel single crystal sample and use the results we obtain to describe the flow of vibrational energy in the methane-surface reaction complex. We show that CHD3 molecules initially excited to v=1, J=2, K=0 of the v 1 symmetric C-H stretching mode will dissociate exclusively via C-H cleavage on Ni(111). This result highlights the localization of vibrational energy in the reaction complex, despite the presence of many energy exchange channels with the high state-density surface. We demonstrate, for the first time, highly parallel bond-selective control of a heterogeneously catalyzed reaction. We place our results in the context of recent experiments investigating IVR for molecules in both the gas phase and liquid solutions. If IVR is fast on the reaction timescale, vibrational energy would be randomly distributed throughout the nascent methane-surface reaction complex and vibrational mode-specific behavior would not occur. The short timescale of a direct gas-surface collision may explain how the exchange of energy via IVR is limited to only a small subset of the energetic configurations available to the reaction complex. This framework

  17. Too Few Apples: The Challenge of Declining Enrolments and Teacher Redundancy in Canada.

    Science.gov (United States)

    Chamberlin, Richard J.

    This study provides a review of the nature and success of programs dealing with excess teacher supply. The causes and effects of teacher redundancy are discussed, and methods of supply and demand planning are examined. Strategies to deal with inservice retraining and programs that present career alternatives are reviewed. Among the solutions…

  18. Surface control alloy substrates and methods of manufacture therefor

    Energy Technology Data Exchange (ETDEWEB)

    Fritzemeier, Leslie G. (Mendon, MA); Li, Qi (Marlborough, MA); Rupich, Martin W. (Framingham, MA); Thompson, Elliott D. (Coventry, RI); Siegal, Edward J. (Malden, MA); Thieme, Cornelis Leo Hans (Westborough, MA); Annavarapu, Suresh (Brookline, MA); Arendt, Paul N. (Los Alamos, NM); Foltyn, Stephen R. (Los Alamos, NM)

    2004-05-04

    Methods and articles for controlling the surface of an alloy substrate for deposition of an epitaxial layer. The invention includes the use of an intermediate layer to stabilize the substrate surface against oxidation for subsequent deposition of an epitaxial layer.

  19. Coal surface control for advanced physical fine coal cleaning technologies

    Energy Technology Data Exchange (ETDEWEB)

    Morsi, B.I.; Chiang, S.H.; Sharkey, A.; Blachere, J.; Klinzing, G.; Araujo, G.; Cheng, Y.S.; Gray, R.; Streeter, R.; Bi, H.; Campbell, P.; Chiarlli, P.; Ciocco, M.; Hittle, L.; Kim, S.; Kim, Y.; Perez, L.; Venkatadri, R.

    1992-01-01

    This final report presents the research work carried out on the Coal Surface Control for Advanced Physical Fine Coal Cleaning Technologies project, sponsored by the US Department of Energy, Pittsburgh Energy Technology Center (DOE/PETC). The project was to support the engineering development of the selective agglomeration technology in order to reduce the sulfur content of US coals for controlling SO[sub 2] emissions (i.e., acid rain precursors). The overall effort was a part of the DOE/PETCs Acid Rain Control Initiative (ARCI). The overall objective of the project is to develop techniques for coal surface control prior to the advanced physical fine coal cleaning process of selective agglomeration in order to achieve 85% pyrite sulfur rejection at an energy recovery greater than 85% based on run-of-mine coal. The surface control is meant to encompass surface modification during grinding and laboratory beneficiation testing. The project includes the following tasks: Project planning; methods for analysis of samples; development of standard beneficiation test; grinding studies; modification of particle surface; and exploratory R D and support. The coal samples used in this project include three base coals, Upper Freeport - Indiana County, PA, Pittsburgh NO. 8 - Belmont County, OH, and Illinois No. 6 - Randolph County, IL, and three additional coals, Upper Freeport - Grant County- WV, Kentucky No. 9 Hopkins County, KY, and Wyodak - Campbell County, WY. A total of 149 drums of coal were received.

  20. Controlled adsorption of cytochrome c to nanostructured gold surfaces

    International Nuclear Information System (INIS)

    Gomes, Inês; Feio, Maria J.; Santos, Nuno C.; Eaton, Peter; Serro, Ana Paula; Saramago, Benilde; Pereira, Eulália; Franco, Ricardo

    2012-01-01

    Controlled electrostatic physisorption of horse heart cytochrome c (Cyt c) onto nanostructured gold surfaces was investigated using Quartz-Crystal Microbalance measurements in planar gold surfaces with or without functionalization using a self-assembled monolayer (SAM) of the alkanethiol mercaptoundecanoic acid (MUA). MUA is a useful functionalization ligand for gold surfaces, shedding adsorbed biomolecules from the excessive electron density of the metal. A parallel analysis was conducted in the corresponding curved surfaces of 15 nm gold nanoparticles (AuNPs), using zeta-potential and UV– visible spectroscopy. Atomic Force Microscopy of both types of functionalized gold surfaces with a MUA SAM, allowed for visualization of Cyt c deposits on the nanostructured gold surface. The amount of Cyt c adsorbed onto the gold surface could be controlled by the solution pH. For the assays conducted at pH 4.5, when MUA SAM- functionalized planar gold surfaces are positive or neutral, and Cyt c has a positive net charge, only 13 % of the planar gold surface area was coated with protein. In contrast, at pH 7.4, when MUA SAM-functionalized planar gold surfaces and Cyt c have opposite charges, a protein coverage of 28 % could be observed implying an adsorption process strongly governed by electrostatic forces. Cyt c adsorption on planar and curved gold surfaces are found to be greatly favored by the presence of a MUA-capping layer. In particular, on the AuNPs, the binding constant is three times larger than the binding constant obtained for the original citrate-capped AuNPs.

  1. Controlled adsorption of cytochrome c to nanostructured gold surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Gomes, Ines [Faculdade de Ciencias e Tecnologia, Universidade Nova de Lisboa, REQUIMTE, Departamento de Quimica (Portugal); Feio, Maria J. [Faculdade de Ciencias da Universidade do Porto, REQUIMTE, Departamento de Quimica e Bioquimica (Portugal); Santos, Nuno C. [Faculdade de Medicina da Universidade de Lisboa, Instituto de Medicina Molecular (Portugal); Eaton, Peter [Faculdade de Ciencias da Universidade do Porto, REQUIMTE, Departamento de Quimica e Bioquimica (Portugal); Serro, Ana Paula; Saramago, Benilde [Centro de Quimica Estrutural, Instituto Superior Tecnico (Portugal); Pereira, Eulalia [Faculdade de Ciencias da Universidade do Porto, REQUIMTE, Departamento de Quimica e Bioquimica (Portugal); Franco, Ricardo, E-mail: ricardo.franco@fct.unl.pt [Faculdade de Ciencias e Tecnologia, Universidade Nova de Lisboa, REQUIMTE, Departamento de Quimica (Portugal)

    2012-12-15

    Controlled electrostatic physisorption of horse heart cytochrome c (Cyt c) onto nanostructured gold surfaces was investigated using Quartz-Crystal Microbalance measurements in planar gold surfaces with or without functionalization using a self-assembled monolayer (SAM) of the alkanethiol mercaptoundecanoic acid (MUA). MUA is a useful functionalization ligand for gold surfaces, shedding adsorbed biomolecules from the excessive electron density of the metal. A parallel analysis was conducted in the corresponding curved surfaces of 15 nm gold nanoparticles (AuNPs), using zeta-potential and UV- visible spectroscopy. Atomic Force Microscopy of both types of functionalized gold surfaces with a MUA SAM, allowed for visualization of Cyt c deposits on the nanostructured gold surface. The amount of Cyt c adsorbed onto the gold surface could be controlled by the solution pH. For the assays conducted at pH 4.5, when MUA SAM- functionalized planar gold surfaces are positive or neutral, and Cyt c has a positive net charge, only 13 % of the planar gold surface area was coated with protein. In contrast, at pH 7.4, when MUA SAM-functionalized planar gold surfaces and Cyt c have opposite charges, a protein coverage of 28 % could be observed implying an adsorption process strongly governed by electrostatic forces. Cyt c adsorption on planar and curved gold surfaces are found to be greatly favored by the presence of a MUA-capping layer. In particular, on the AuNPs, the binding constant is three times larger than the binding constant obtained for the original citrate-capped AuNPs.

  2. Design of a redundant meteorological station for a BWR reactor

    International Nuclear Information System (INIS)

    Ramirez S, R.; Celis del Angel, L.; Bucio, F.; Rivero, T.; Palacios, J.

    2008-01-01

    In this work the design of a meteorological station for a reactor type BWR is proposed. Two independent channels of data acquisition that allow him to have a bigger readiness is exposed. It is incorporate sensors without mobile parts to measure speed, wind direction and pluvial precipitation. It also counts, with sensors of global solar radiation, net radiation, barometric pressure, relative humidity and ambient temperature; with them they are possible to be calculated, moreover, other variables as temperature differential, dew point and atmospheric stability. The sensors are placed on a tower to different heights and send their information (each second) to a local registration system, the one which in turn, it remits the data to the monitoring office so that a computer is linked with the system, display and management the information in real time and automatic way. The redundant structure allows that in the event of maintenance the data acquisition is not interrupted, even if the information is transferred to another place. In all the station sections it is used protocols of standard communication to allow that a great quantity of devices can be connected without major problem. The above-mentioned would allow to the operators in the control room to have reliable information during the whole time of the reactor operation. (Author)

  3. A particle-based simplified swarm optimization algorithm for reliability redundancy allocation problems

    International Nuclear Information System (INIS)

    Huang, Chia-Ling

    2015-01-01

    This paper proposes a new swarm intelligence method known as the Particle-based Simplified Swarm Optimization (PSSO) algorithm while undertaking a modification of the Updating Mechanism (UM), called N-UM and R-UM, and simultaneously applying an Orthogonal Array Test (OA) to solve reliability–redundancy allocation problems (RRAPs) successfully. One difficulty of RRAP is the need to maximize system reliability in cases where the number of redundant components and the reliability of corresponding components in each subsystem are simultaneously decided with nonlinear constraints. In this paper, four RRAP benchmarks are used to display the applicability of the proposed PSSO that advances the strengths of both PSO and SSO to enable optimizing the RRAP that belongs to mixed-integer nonlinear programming. When the computational results are compared with those of previously developed algorithms in existing literature, the findings indicate that the proposed PSSO is highly competitive and performs well. - Highlights: • This paper proposes a particle-based simplified swarm optimization algorithm (PSSO) to optimize RRAP. • Furthermore, the UM and an OA are adapted to advance in optimizing RRAP. • Four systems are introduced and the results demonstrate the PSSO performs particularly well

  4. Light-responsive smart surface with controllable wettability and excellent stability.

    Science.gov (United States)

    Zhou, Yin-Ning; Li, Jin-Jin; Zhang, Qing; Luo, Zheng-Hong

    2014-10-21

    Novel fluorinated gradient copolymer was designed for smart surface with light-responsive controllable wettability and excellent stability. The switchable mechanism and physicochemical characteristics of the as-prepared surface decorated by designed polymeric material were investigated by ultraviolet-visible (UV-vis) spectrum, scanning electron microscope (SEM), atomic force microscope (AFM), and X-ray photoelectron spectroscopy (XPS). Thanks to the functional film and surface roughening, etched silicon surface fabricated by copolymer involving spiropyran (Sp) moieties possesses a fairly large variation range of WCA (28.1°) and achieves the transformation between hydrophilicity (95.2° 109.2°) relative to blank sample (109.2°). The synthetic strategy and developed smart surface offer a promising application in coating with controllable wettability, which bridge the gap between chemical structure and material properties.

  5. An efficient heuristic versus a robust hybrid meta-heuristic for general framework of serial-parallel redundancy problem

    International Nuclear Information System (INIS)

    Sadjadi, Seyed Jafar; Soltani, R.

    2009-01-01

    We present a heuristic approach to solve a general framework of serial-parallel redundancy problem where the reliability of the system is maximized subject to some general linear constraints. The complexity of the redundancy problem is generally considered to be NP-Hard and the optimal solution is not normally available. Therefore, to evaluate the performance of the proposed method, a hybrid genetic algorithm is also implemented whose parameters are calibrated via Taguchi's robust design method. Then, various test problems are solved and the computational results indicate that the proposed heuristic approach could provide us some promising reliabilities, which are fairly close to optimal solutions in a reasonable amount of time.

  6. Performance and delay analysis of hybrid ARQ with incremental redundancy over double rayleigh fading channels

    KAUST Repository

    Chelli, Ali; Zedini, Emna; Alouini, Mohamed-Slim; Barry, John R.; Pä tzold, Matthias

    2014-01-01

    the performance of HARQ from an information theoretic perspective. Analytical expressions are derived for the \\epsilon-outage capacity, the average number of transmissions, and the average transmission rate of HARQ with incremental redundancy assuming a maximum

  7. Notice of Violation of IEEE Publication PrinciplesJoint Redundant Residue Number Systems and Module Isolation for Mitigating Single Event Multiple Bit Upsets in Datapath

    Science.gov (United States)

    Li, Lei; Hu, Jianhao

    2010-12-01

    Notice of Violation of IEEE Publication Principles"Joint Redundant Residue Number Systems and Module Isolation for Mitigating Single Event Multiple Bit Upsets in Datapath"by Lei Li and Jianhao Hu,in the IEEE Transactions on Nuclear Science, vol.57, no.6, Dec. 2010, pp. 3779-3786After careful and considered review of the content and authorship of this paper by a duly constituted expert committee, this paper has been found to be in violation of IEEE's Publication Principles.This paper contains substantial duplication of original text from the paper cited below. The original text was copied without attribution (including appropriate references to the original author(s) and/or paper title) and without permission.Due to the nature of this violation, reasonable effort should be made to remove all past references to this paper, and future references should be made to the following articles:"Multiple Error Detection and Correction Based on Redundant Residue Number Systems"by Vik Tor Goh and M.U. Siddiqi,in the IEEE Transactions on Communications, vol.56, no.3, March 2008, pp.325-330"A Coding Theory Approach to Error Control in Redundant Residue Number Systems. I: Theory and Single Error Correction"by H. Krishna, K-Y. Lin, and J-D. Sun, in the IEEE Transactions on Circuits and Systems II: Analog and Digital Signal Processing, vol.39, no.1, Jan 1992, pp.8-17In this paper, we propose a joint scheme which combines redundant residue number systems (RRNS) with module isolation (MI) for mitigating single event multiple bit upsets (SEMBUs) in datapath. The proposed hardening scheme employs redundant residues to improve the fault tolerance for datapath and module spacings to guarantee that SEMBUs caused by charge sharing do not propagate among the operation channels of different moduli. The features of RRNS, such as independence, parallel and error correction, are exploited to establish the radiation hardening architecture for the datapath in radiation environments. In the proposed

  8. Remote Control of Tissue Interactions via Engineered Photo-switchable Cell Surfaces

    Science.gov (United States)

    Luo, Wei; Pulsipher, Abigail; Dutta, Debjit; Lamb, Brian M.; Yousaf, Muhammad N.

    2014-09-01

    We report a general cell surface molecular engineering strategy via liposome fusion delivery to create a dual photo-active and bio-orthogonal cell surface for remote controlled spatial and temporal manipulation of microtissue assembly and disassembly. Cell surface tailoring of chemoselective functional groups was achieved by a liposome fusion delivery method and quantified by flow cytometry and characterized by a new cell surface lipid pull down mass spectrometry strategy. Dynamic co-culture spheroid tissue assembly in solution and co-culture tissue multilayer assembly on materials was demonstrated by an intercellular photo-oxime ligation that could be remotely cleaved and disassembled on demand. Spatial and temporal control of microtissue structures containing multiple cell types was demonstrated by the generation of patterned multilayers for controlling stem cell differentiation. Remote control of cell interactions via cell surface engineering that allows for real-time manipulation of tissue dynamics may provide tools with the scope to answer fundamental questions of cell communication and initiate new biotechnologies ranging from imaging probes to drug delivery vehicles to regenerative medicine, inexpensive bioreactor technology and tissue engineering therapies.

  9. Polycomb complexes act redundantly to repress genomic repeats and genes

    DEFF Research Database (Denmark)

    Leeb, Martin; Pasini, Diego; Novatchkova, Maria

    2010-01-01

    Polycomb complexes establish chromatin modifications for maintaining gene repression and are essential for embryonic development in mice. Here we use pluripotent embryonic stem (ES) cells to demonstrate an unexpected redundancy between Polycomb-repressive complex 1 (PRC1) and PRC2 during...... the formation of differentiated cells. ES cells lacking the function of either PRC1 or PRC2 can differentiate into cells of the three germ layers, whereas simultaneous loss of PRC1 and PRC2 abrogates differentiation. On the molecular level, the differentiation defect is caused by the derepression of a set...

  10. Redundancy gains in simple responses and go/no-go tasks

    DEFF Research Database (Denmark)

    Gondan, Matthias; Götze, C.; Greenlee, M.W.

    2010-01-01

    In divided-attention tasks with two classes of target stimuli, participants typically respond more quickly if both targets are presented simultaneously, as compared with single-target presentation (redundant-signals effect). Different explanations exist for this effect, including serial, parallel...... times in both the simple and go/no-go responses were well explained by a common coactivation model assuming linear superposition of modality-specific activation. In Experiment 2, the go/no-go task was made more difficult. Participants had to respond to high-frequency tones or right-tilted Gabor patches...

  11. Redundant mechanisms are involved in suppression of default cell fates during embryonic mesenchyme and notochord induction in ascidians.

    Science.gov (United States)

    Kodama, Hitoshi; Miyata, Yoshimasa; Kuwajima, Mami; Izuchi, Ryoichi; Kobayashi, Ayumi; Gyoja, Fuki; Onuma, Takeshi A; Kumano, Gaku; Nishida, Hiroki

    2016-08-01

    During embryonic induction, the responding cells invoke an induced developmental program, whereas in the absence of an inducing signal, they assume a default uninduced cell fate. Suppression of the default fate during the inductive event is crucial for choice of the binary cell fate. In contrast to the mechanisms that promote an induced cell fate, those that suppress the default fate have been overlooked. Upon induction, intracellular signal transduction results in activation of genes encoding key transcription factors for induced tissue differentiation. It is elusive whether an induced key transcription factor has dual functions involving suppression of the default fates and promotion of the induced fate, or whether suppression of the default fate is independently regulated by other factors that are also downstream of the signaling cascade. We show that during ascidian embryonic induction, default fates were suppressed by multifold redundant mechanisms. The key transcription factor, Twist-related.a, which is required for mesenchyme differentiation, and another independent transcription factor, Lhx3, which is dispensable for mesenchyme differentiation, sequentially and redundantly suppress the default muscle fate in induced mesenchyme cells. Similarly in notochord induction, Brachyury, which is required for notochord differentiation, and other factors, Lhx3 and Mnx, are likely to suppress the default nerve cord fate redundantly. Lhx3 commonly suppresses the default fates in two kinds of induction. Mis-activation of the autonomously executed default program in induced cells is detrimental to choice of the binary cell fate. Multifold redundant mechanisms would be required for suppression of the default fate to be secure. Copyright © 2016 Elsevier Inc. All rights reserved.

  12. Generalized Friedmann-Robertson-Walker metric and redundancy in the generalized Einstein equations

    International Nuclear Information System (INIS)

    Kao, W.F.; Pen, U.

    1991-01-01

    A nontrivial redundancy relation, due to the differential structure of the gravitational Bianchi identity as well as the symmetry of the Friedmann-Robertson-Walker metric, in the gravitational field equation is clarified. A generalized Friedmann-Robertson-Walker metric is introduced in order to properly define a one-dimensional reduced problem which offers an alternative approach to obtain the gravitational field equations on Friedmann-Robertson-Walker spaces

  13. Soil Carbon Dioxide Production and Surface Fluxes: Subsurface Physical Controls

    Science.gov (United States)

    Risk, D.; Kellman, L.; Beltrami, H.

    Soil respiration is a critical determinant of landscape carbon balance. Variations in soil temperature and moisture patterns are important physical processes controlling soil respiration which need to be better understood. Relationships between soil respi- ration and physical controls are typically addressed using only surface flux data but other methods also exist which permit more rigorous interpretation of soil respira- tion processes. Here we use a combination of subsurface CO_{2} concentrations, surface CO_{2} fluxes and detailed physical monitoring of the subsurface envi- ronment to examine physical controls on soil CO_{2} production at four climate observatories in Eastern Canada. Results indicate that subsurface CO_{2} produc- tion is more strongly correlated to the subsurface thermal environment than the surface CO_{2} flux. Soil moisture was also found to have an important influence on sub- surface CO_{2} production, particularly in relation to the soil moisture - soil profile diffusivity relationship. Non-diffusive profile CO_{2} transport appears to be im- portant at these sites, resulting in a de-coupling of summertime surface fluxes from subsurface processes and violating assumptions that surface CO_{2} emissions are the result solely of diffusion. These results have implications for the study of soil respiration across a broad range of terrestrial environments.

  14. Controlling the Nanoscale Patterning of AuNPs on Silicon Surfaces

    Directory of Open Access Journals (Sweden)

    Chris J. Allender

    2013-03-01

    Full Text Available This study evaluates the effectiveness of vapour-phase deposition for creating sub-monolayer coverage of aminopropyl triethoxysilane (APTES on silicon in order to exert control over subsequent gold nanoparticle deposition. Surface coverage was evaluated indirectly by observing the extent to which gold nanoparticles (AuNPs deposited onto the modified silicon surface. By varying the distance of the silicon wafer from the APTES source and concentration of APTES in the evaporating media, control over subsequent gold nanoparticle deposition was achievable to an extent. Fine control over AuNP deposition (AuNPs/μm2 however, was best achieved by adjusting the ionic concentration of the AuNP-depositing solution. Furthermore it was demonstrated that although APTES was fully removed from the silicon surface following four hours incubation in water, the gold nanoparticle-amino surface complex was stable under the same conditions. Atomic force microscopy (AFM and X-ray photoelectron spectroscopy (XPS were used to study these affects.

  15. Structural redundancy of data from wastewater treatment systems. Determination of individual balance equations.

    Science.gov (United States)

    Spindler, A

    2014-06-15

    Although data reconciliation is intensely applied in process engineering, almost none of its powerful methods are employed for validation of operational data from wastewater treatment plants. This is partly due to some prerequisites that are difficult to meet including steady state, known variances of process variables and absence of gross errors. However, an algorithm can be derived from the classical approaches to data reconciliation that allows to find a comprehensive set of equations describing redundancy in the data when measured and unmeasured variables (flows and concentrations) are defined. This is a precondition for methods of data validation based on individual mass balances such as CUSUM charts. The procedure can also be applied to verify the necessity of existing or additional measurements with respect to the improvement of the data's redundancy. Results are given for a large wastewater treatment plant. The introduction aims at establishing a link between methods known from data reconciliation in process engineering and their application in wastewater treatment. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. A monitor for the laboratory evaluation of control integrity in digital control systems operating in harsh electromagnetic environments

    Science.gov (United States)

    Belcastro, Celeste M.; Fischl, Robert; Kam, Moshe

    1992-01-01

    This paper presents a strategy for dynamically monitoring digital controllers in the laboratory for susceptibility to electromagnetic disturbances that compromise control integrity. The integrity of digital control systems operating in harsh electromagnetic environments can be compromised by upsets caused by induced transient electrical signals. Digital system upset is a functional error mode that involves no component damage, can occur simultaneously in all channels of a redundant control computer, and is software dependent. The motivation for this work is the need to develop tools and techniques that can be used in the laboratory to validate and/or certify critical aircraft controllers operating in electromagnetically adverse environments that result from lightning, high-intensity radiated fields (HIRF), and nuclear electromagnetic pulses (NEMP). The detection strategy presented in this paper provides dynamic monitoring of a given control computer for degraded functional integrity resulting from redundancy management errors, control calculation errors, and control correctness/effectiveness errors. In particular, this paper discusses the use of Kalman filtering, data fusion, and statistical decision theory in monitoring a given digital controller for control calculation errors.

  17. Redundant information encoding in QED during decoherence

    Science.gov (United States)

    Tuziemski, J.; Witas, P.; Korbicz, J. K.

    2018-01-01

    Broadly understood decoherence processes in quantum electrodynamics, induced by neglecting either the radiation [L. Landau, Z. Phys. 45, 430 (1927), 10.1007/BF01343064] or the charged matter [N. Bohr and L. Rosenfeld, K. Danske Vidensk. Selsk, Math.-Fys. Medd. XII, 8 (1933)], have been studied from the dawn of the theory. However, what happens in between, when a part of the radiation may be observed, as is the case in many real-life situations, has not been analyzed yet. We present such an analysis for a nonrelativistic, pointlike charge and thermal radiation. In the dipole approximation, we solve the dynamics and show that there is a regime where, despite the noise, the observed field carries away almost perfect and hugely redundant information about the charge momentum. We analyze a partial charge-field state and show that it approaches a so-called spectrum broadcast structure.

  18. Formation control of marine surface craft: a Lagrangian approach

    DEFF Research Database (Denmark)

    Ihle, Ivar-Andre F.; Jouffroy, Jerome; Fossen, Thor I.

    2006-01-01

    This paper presents a method for formation control of marine surface craft inspired by Lagrangian mechanics. The desired formation configuration and response of the marine surface craft are given as a set of constraints in analytical mechanics. Thus, constraints forces arise and feedback from...

  19. Different-Level Simultaneous Minimization Scheme for Fault Tolerance of Redundant Manipulator Aided with Discrete-Time Recurrent Neural Network.

    Science.gov (United States)

    Jin, Long; Liao, Bolin; Liu, Mei; Xiao, Lin; Guo, Dongsheng; Yan, Xiaogang

    2017-01-01

    By incorporating the physical constraints in joint space, a different-level simultaneous minimization scheme, which takes both the robot kinematics and robot dynamics into account, is presented and investigated for fault-tolerant motion planning of redundant manipulator in this paper. The scheme is reformulated as a quadratic program (QP) with equality and bound constraints, which is then solved by a discrete-time recurrent neural network. Simulative verifications based on a six-link planar redundant robot manipulator substantiate the efficacy and accuracy of the presented acceleration fault-tolerant scheme, the resultant QP and the corresponding discrete-time recurrent neural network.

  20. Control surface wettability with nanoparticles from phase-change materials

    NARCIS (Netherlands)

    Ten Brink, G. H.; van het Hof, P. J.; Chen, B.; Sedighi, M.; Kooi, B. J.; Palasantzas, G.

    2016-01-01

    The wetting state of surfaces can be controlled physically from the highly hydrophobic to hydrophilic states using the amorphous-to-crystalline phase transition of Ge2Sb2Te5 (GST) nanoparticles as surfactant. Indeed, contact angle measurements show that by increasing the surface coverage of the

  1. Redundant dopaminergic activity may enable compensatory axonal sprouting in Parkinson disease.

    Science.gov (United States)

    Arkadir, David; Bergman, Hagai; Fahn, Stanley

    2014-03-25

    Neurodegenerative diseases become clinically apparent only after a substantial population of neurons is lost. This raises the possibility of compensatory mechanisms in the early phase of these diseases. The importance of understanding these mechanisms cannot be underestimated because it may guide future disease-modifying strategies. Because the anatomy and physiology of the nigrostriatal dopaminergic pathways have been well described, the study of Parkinson disease can offer insight into these early compensatory mechanisms. Collateral axonal sprouting of dopaminergic terminals into the denervated striatum is the most studied compensatory mechanism in animal (almost exclusively rodent) models of Parkinson disease and is correlated with behavioral recovery after partial lesions. This sprouting, however, does not respect the normal anatomy of the original nigrostriatal pathways and leads to aberrant neuronal networks. We suggest here that the unique physiologic property of the dopaminergic innervation of the striatum, namely redundancy of information encoding, is crucial to the efficacy of compensatory axonal sprouting in the presence of aberrant anatomical connections. Redundant information encoding results from the similarity of representation of salient and rewarding events by many dopaminergic neurons, from the wide axonal field of a single dopaminergic neuron in the striatum, and from the nonspecific spatial effect of dopamine on striatal neurons (volume conductance). Finally, we discuss the relevance of these findings in animal models to human patients with Parkinson disease.

  2. Microsatellite-aided detection of genetic redundancy improves management of the International Cocoa Genebank, Trinidad

    Science.gov (United States)

    Cacao (Theobroma cacao L.), the tree from which cocoa butter and chocolate is derived, is conserved in field genebanks. The largest of these ex situ collections in the public domain is the International Cocoa Genebank, Trinidad (ICG,T). Reduction of genetic redundancy is essential to improve the acc...

  3. Electric fields control the orientation of peptides irreversibly immobilized on radical-functionalized surfaces.

    Science.gov (United States)

    Martin, Lewis J; Akhavan, Behnam; Bilek, Marcela M M

    2018-01-24

    Surface functionalization of an implantable device with bioactive molecules can overcome adverse biological responses by promoting specific local tissue integration. Bioactive peptides have advantages over larger protein molecules due to their robustness and sterilizability. Their relatively small size presents opportunities to control the peptide orientation on approach to a surface to achieve favourable presentation of bioactive motifs. Here we demonstrate control of the orientation of surface-bound peptides by tuning electric fields at the surface during immobilization. Guided by computational simulations, a peptide with a linear conformation in solution is designed. Electric fields are used to control the peptide approach towards a radical-functionalized surface. Spontaneous, irreversible immobilization is achieved when the peptide makes contact with the surface. Our findings show that control of both peptide orientation and surface concentration is achieved simply by varying the solution pH or by applying an electric field as delivered by a small battery.

  4. Real-time instrument-failure detection in the LOFT pressurizer using functional redundancy

    International Nuclear Information System (INIS)

    Tylee, J.L.

    1982-07-01

    The functional redundancy approach to detecting instrument failures in a pressurized water reactor (PWR) pressurizer is described and evaluated. This real-time method uses a bank of Kalman filters (one for each instrument) to generate optimal estimates of the pressurizer state. By performing consistency checks between the output of each filter, failed instruments can be identified. Simulation results and actual pressurizer data are used to demonstrate the capabilities of the technique

  5. Fabrication of Superhydrophobic Surfaces with Controllable Electrical Conductivity and Water Adhesion.

    Science.gov (United States)

    Ye, Lijun; Guan, Jipeng; Li, Zhixiang; Zhao, Jingxin; Ye, Cuicui; You, Jichun; Li, Yongjin

    2017-02-14

    A facile and versatile strategy for fabricating superhydrophobic surfaces with controllable electrical conductivity and water adhesion is reported. "Vine-on-fence"-structured and cerebral cortex-like superhydrophobic surfaces are constructed by filtering a suspension of multiwalled carbon nanotubes (MWCNTs), using polyoxymethylene nonwovens as the filter paper. The nonwovens with micro- and nanoporous two-tier structures act as the skeleton, introducing a microscale structure. The MWCNTs act as nanoscale structures, creating hierarchical surface roughness. The surface topography and the electrical conductivity of the superhydrophobic surfaces are controlled by varying the MWCNT loading. The vine-on-fence-structured surfaces exhibit "sticky" superhydrophobicity with high water adhesion. The cerebral cortex-like surfaces exhibit self-cleaning properties with low water adhesion. The as-prepared superhydrophobic surfaces are chemically resistant to acidic and alkaline environments of pH 2-12. They therefore have potential in applications such as droplet-based microreactors and thin-film microextraction. These findings aid our understanding of the role that surface topography plays in the design and fabrication of superhydrophobic surfaces with different water-adhesion properties.

  6. Permanent isolation surface barrier development plan

    International Nuclear Information System (INIS)

    Wing, N.R.

    1994-01-01

    The exhumation and treatment of wastes may not always be the preferred alternative in the remediation of a waste site. In-place disposal alternatives, under certain circumstances, may be the most desirable alternatives to use in the protection of human health and the environment. The implementation of an in-place disposal alternative will likely require some type of protective covering that will provide long-term isolation of the wastes from the accessible environment. Even if the wastes are exhumed and treated, a long-term barrier may still be needed to adequately dispose of the treated wastes or any remaining waste residuals. Currently, no open-quotes provenclose quotes long-term barrier is available. The Hanford Site Permanent Isolation Surface Barrier Development Program (BDP) was organized to develop the technology needed to provide a long-term surface barrier capability for the Hanford Site. The permanent isolation barrier technology also could be used at other sites. Permanent isolation barriers use engineered layers of natural materials to create an integrated structure with redundant protective features. Drawings of conceptual permanent isolation surface barriers are shown. The natural construction materials (e.g., fine soil, sand, gravel, riprap, asphalt) have been selected to optimize barrier performance and longevity. The objective of current designs is to use natural materials to develop a maintenance-free permanent isolation surface barrier that isolates wastes for a minimum of 1,000 years by limiting water drainage to near-zero amounts; reducing the likelihood of plant, animal, and human intrusion; controlling the exhalation of noxious gases; and minimizing erosion-related problems

  7. Permanent isolation surface barrier development plan

    Energy Technology Data Exchange (ETDEWEB)

    Wing, N.R.

    1994-01-01

    The exhumation and treatment of wastes may not always be the preferred alternative in the remediation of a waste site. In-place disposal alternatives, under certain circumstances, may be the most desirable alternatives to use in the protection of human health and the environment. The implementation of an in-place disposal alternative will likely require some type of protective covering that will provide long-term isolation of the wastes from the accessible environment. Even if the wastes are exhumed and treated, a long-term barrier may still be needed to adequately dispose of the treated wastes or any remaining waste residuals. Currently, no {open_quotes}proven{close_quotes} long-term barrier is available. The Hanford Site Permanent Isolation Surface Barrier Development Program (BDP) was organized to develop the technology needed to provide a long-term surface barrier capability for the Hanford Site. The permanent isolation barrier technology also could be used at other sites. Permanent isolation barriers use engineered layers of natural materials to create an integrated structure with redundant protective features. Drawings of conceptual permanent isolation surface barriers are shown. The natural construction materials (e.g., fine soil, sand, gravel, riprap, asphalt) have been selected to optimize barrier performance and longevity. The objective of current designs is to use natural materials to develop a maintenance-free permanent isolation surface barrier that isolates wastes for a minimum of 1,000 years by limiting water drainage to near-zero amounts; reducing the likelihood of plant, animal, and human intrusion; controlling the exhalation of noxious gases; and minimizing erosion-related problems.

  8. The human brain maintains contradictory and redundant auditory sensory predictions.

    Directory of Open Access Journals (Sweden)

    Marika Pieszek

    Full Text Available Computational and experimental research has revealed that auditory sensory predictions are derived from regularities of the current environment by using internal generative models. However, so far, what has not been addressed is how the auditory system handles situations giving rise to redundant or even contradictory predictions derived from different sources of information. To this end, we measured error signals in the event-related brain potentials (ERPs in response to violations of auditory predictions. Sounds could be predicted on the basis of overall probability, i.e., one sound was presented frequently and another sound rarely. Furthermore, each sound was predicted by an informative visual cue. Participants' task was to use the cue and to discriminate the two sounds as fast as possible. Violations of the probability based prediction (i.e., a rare sound as well as violations of the visual-auditory prediction (i.e., an incongruent sound elicited error signals in the ERPs (Mismatch Negativity [MMN] and Incongruency Response [IR]. Particular error signals were observed even in case the overall probability and the visual symbol predicted different sounds. That is, the auditory system concurrently maintains and tests contradictory predictions. Moreover, if the same sound was predicted, we observed an additive error signal (scalp potential and primary current density equaling the sum of the specific error signals. Thus, the auditory system maintains and tolerates functionally independently represented redundant and contradictory predictions. We argue that the auditory system exploits all currently active regularities in order to optimally prepare for future events.

  9. Control Allocation for Overactuated Systems

    National Research Council Canada - National Science Library

    Oppenheimer, Michael W; Doman, David B

    2006-01-01

    Much emphasis has been placed on overactuated systems for air vehicles. Overactuating an air vehicle provides a certain amount of redundancy for the flight control system, thus potentially allowing for recovery from off-nominal conditions...

  10. Plasma surface interactions in controlled fusion devices

    Energy Technology Data Exchange (ETDEWEB)

    Ghendrih, Ph.; Becoulet, M.; Costanzo, L. [and others

    2000-07-01

    This report brings together all the contributions of EURATOM/CEA association to the 14. international conference on plasma surface interactions in controlled fusion devices. 24 papers are presented and they deal mainly with the ergodic divertor and the first wall of Tore-supra tokamak.

  11. Plasma surface interactions in controlled fusion devices

    International Nuclear Information System (INIS)

    Ghendrih, Ph.; Becoulet, M.; Costanzo, L.

    2000-07-01

    This report brings together all the contributions of EURATOM/CEA association to the 14. international conference on plasma surface interactions in controlled fusion devices. 24 papers are presented and they deal mainly with the ergodic divertor and the first wall of Tore-supra tokamak

  12. Repository surface design site layout analysis

    International Nuclear Information System (INIS)

    Montalvo, H.R.

    1998-01-01

    The purpose of this analysis is to establish the arrangement of the Yucca Mountain Repository surface facilities and features near the North Portal. The analysis updates and expands the North Portal area site layout concept presented in the ACD, including changes to reflect the resizing of the Waste Handling Building (WHB), Waste Treatment Building (WTB), Carrier Preparation Building (CPB), and site parking areas; the addition of the Carrier Washdown Buildings (CWBs); the elimination of the Cask Maintenance Facility (CMF); and the development of a concept for site grading and flood control. The analysis also establishes the layout of the surface features (e.g., roads and utilities) that connect all the repository surface areas (North Portal Operations Area, South Portal Development Operations Area, Emplacement Shaft Surface Operations Area, and Development Shaft Surface Operations Area) and locates an area for a potential lag storage facility. Details of South Portal and shaft layouts will be covered in separate design analyses. The objective of this analysis is to provide a suitable level of design for the Viability Assessment (VA). The analysis was revised to incorporate additional material developed since the issuance of Revision 01. This material includes safeguards and security input, utility system input (size and location of fire water tanks and pump houses, potable water and sanitary sewage rates, size of wastewater evaporation pond, size and location of the utility building, size of the bulk fuel storage tank, and size and location of other exterior process equipment), main electrical substation information, redundancy of water supply and storage for the fire support system, and additional information on the storm water retention pond

  13. The Redundancy Effect on Retention and Transfer for Individuals with High Symptoms of ADHD

    Science.gov (United States)

    Brown, Victoria; Lewis, David; Toussaint, Mario

    2016-01-01

    The multimedia elements of text and audio need to be carefully integrated together to maximize the impact of those elements for learning in a multimedia environment. Redundancy information presented through audio and visual channels can inhibit learning for individuals diagnosed with ADHD, who may experience challenges in the processing of…

  14. Temperature-Responsive Anisotropic Slippery Surface for Smart Control of the Droplet Motion.

    Science.gov (United States)

    Wang, By Lili; Heng, Liping; Jiang, Lei

    2018-02-28

    Development of stimulus-responsive anisotropic slippery surfaces is important because of the high demand for such materials in the field of liquid directional-driven systems. However, current studies in the field of slippery surfaces are mainly conducted to prepare isotropic slippery surfaces. Although we have developed electric-responsive anisotropic slippery surfaces that enable smart control of the droplet motion, there remain challenges for designing temperature-responsive anisotropic slippery surfaces to control the liquid droplet motion on the surface and in the tube. In this work, temperature-responsive anisotropic slippery surfaces have been prepared by using paraffin, a thermo-responsive phase-transition material, as a lubricating fluid and directional porous polystyrene (PS) films as the substrate. The smart regulation of the droplet motion of several liquids on this surface was accomplished by tuning the substrate temperature. The uniqueness of this surface lies in the use of an anisotropic structure and temperature-responsive lubricating fluids to achieve temperature-driven smart control of the anisotropic motion of the droplets. Furthermore, this surface was used to design temperature-driven anisotropic microreactors and to manipulate liquid transfer in tubes. This work advances the understanding of the principles underlying anisotropic slippery surfaces and provides a promising material for applications in the biochip and microreactor system.

  15. A 8.9-ENOB 2.5-εW 150-KS/s non-binary redundant successive approximation ADC in 0.18-microm CMOS for bio-implanted devices.

    Science.gov (United States)

    Chan, Kok Lim; Lee, Andreas Astuti; Yuan, Xiaojun; Krishna, Kotlanka R; Je, Minkyu

    2010-01-01

    A successive approximation analog-to-digital converter (SAR ADC) with a split-capacitor switching scheme implementing the generalized non-binary redundant SAR algorithm and an energy efficient level shifter is proposed for bio-implanted applications. The generalized non-binary redundant SAR algorithm removes the radix constraint in conventional non-binary redundant SAR algorithm, and the energy efficient level shifter allows optimal power supplies to be chosen independently for the analog and digital blocks. A FOM of 34.7fJ/step has been achieved.

  16. Advanced driver assistance systems: Using multimodal redundant warnings to enhance road safety.

    Science.gov (United States)

    Biondi, Francesco; Strayer, David L; Rossi, Riccardo; Gastaldi, Massimiliano; Mulatti, Claudio

    2017-01-01

    This study investigated whether multimodal redundant warnings presented by advanced assistance systems reduce brake response times. Warnings presented by assistance systems are designed to assist drivers by informing them that evasive driving maneuvers are needed in order to avoid a potential accident. If these warnings are poorly designed, they may distract drivers, slow their responses, and reduce road safety. In two experiments, participants drove a simulated vehicle equipped with a forward collision avoidance system. Auditory, vibrotactile, and multimodal warnings were presented when the time to collision was shorter than five seconds. The effects of these warnings were investigated with participants performing a concurrent cell phone conversation (Exp. 1) or driving in high-density traffic (Exp. 2). Braking times and subjective workload were measured. Multimodal redundant warnings elicited faster braking reaction times. These warnings were found to be effective even when talking on a cell phone (Exp. 1) or driving in dense traffic (Exp. 2). Multimodal warnings produced higher ratings of urgency, but ratings of frustration did not increase compared to other warnings. Findings obtained in these two experiments are important given that faster braking responses may reduce the potential for a collision. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Methane Lunar Surface Thermal Control Test

    Science.gov (United States)

    Plachta, David W.; Sutherlin, Steven G.; Johnson, Wesley L.; Feller, Jeffrey R.; Jurns, John M.

    2012-01-01

    NASA is considering propulsion system concepts for future missions including human return to the lunar surface. Studies have identified cryogenic methane (LCH4) and oxygen (LO2) as a desirable propellant combination for the lunar surface ascent propulsion system, and they point to a surface stay requirement of 180 days. To meet this requirement, a test article was prepared with state-of-the-art insulation and tested in simulated lunar mission environments at NASA GRC. The primary goals were to validate design and models of the key thermal control technologies to store unvented methane for long durations, with a low-density high-performing Multi-layer Insulation (MLI) system to protect the propellant tanks from the environmental heat of low Earth orbit (LEO), Earth to Moon transit, lunar surface, and with the LCH4 initially densified. The data and accompanying analysis shows this storage design would have fallen well short of the unvented 180 day storage requirement, due to the MLI density being much higher than intended, its substructure collapse, and blanket separation during depressurization. Despite the performance issue, insight into analytical models and MLI construction was gained. Such modeling is important for the effective design of flight vehicle concepts, such as in-space cryogenic depots or in-space cryogenic propulsion stages.

  18. Production-on-the-Go Practice: Storyboarding as a Retrospective and Redundant School Literacy Activity

    Science.gov (United States)

    Tan, Lynde

    2013-01-01

    Storyboarding is one common strategy used in teaching young people digital media. This paper argues that in adolescents' literacy practices, they engage in production on the go. The metaphor is described in this paper to put forward the argument that storyboarding can be a retrospective and redundant literacy activity in adolescents' school…

  19. Autonomous navigation - The ARMMS concept. [Autonomous Redundancy and Maintenance Management Subsystem

    Science.gov (United States)

    Wood, L. J.; Jones, J. B.; Mease, K. D.; Kwok, J. H.; Goltz, G. L.; Kechichian, J. A.

    1984-01-01

    A conceptual design is outlined for the navigation subsystem of the Autonomous Redundancy and Maintenance Management Subsystem (ARMMS). The principal function of this navigation subsystem is to maintain the spacecraft over a specified equatorial longitude to within + or - 3 deg. In addition, the navigation subsystem must detect and correct internal faults. It comprises elements for a navigation executive and for orbit determination, trajectory, maneuver planning, and maneuver command. Each of these elements is described. The navigation subsystem is to be used in the DSCS III spacecraft.

  20. Agent Control for Reconfigurable Open Kinematic Chain Manipulators

    Directory of Open Access Journals (Sweden)

    Janez Sluga

    2013-10-01

    Full Text Available This paper presents a method for the autonomous control of differently structured open kinematic chains based on multi-agent system technology. The appropriate level of distributing local autonomy (agents to a manipulative structure is defined, which makes it possible to dynamically change the number, type and structure of manipulative components without modifying their behavioural logic. To achieve fast reconfigurable and scalable manipulative systems, a new multi-agent method is developed for controlling the manipulator kinematics. The new method enables independent manipulator structure from the control system because of its structural and system modularity. The proposed method consists of kinematic equations for use in an agent environment, agent motion-planning algorithms, evaluation functions, agent control logic and kinematic algorithms. The results of simulations and real-world experiments demonstrate the usefulness of the approach for different non-redundant and redundant manipulation structures.

  1. Novel CNC Grinding Process Control for Nanometric Surface Roughness for Aspheric Space Optical Surfaces

    Directory of Open Access Journals (Sweden)

    Jeong-Yeol Han

    2004-06-01

    Full Text Available Optics fabrication process for precision space optical parts includes bound abrasive grinding, loose abrasive lapping and polishing. The traditional bound abrasive grinding with bronze bond cupped diamond wheel leaves the machine marks of about 20 μm rms in height and the subsurface damage of about 1 μm rms in height to be removed by subsequent loose abrasive lapping. We explored an efficient quantitative control of precision CNC grinding. The machining parameters such as grain size, work-piece rotation speed and feed rate were altered while grinding the work-piece surfaces of 20-100 mm in diameter. The input grinding variables and the resulting surface quality data were used to build grinding prediction models using empirical and multi-variable regression analysis. The effectiveness of such grinding prediction models was then examined by running a series of precision CNC grinding operation with a set of controlled input variables and predicted output surface quality indicators. The experiment achieved the predictability down to ±20 nm in height and the surface roughness down to 36 nm in height. This study contributed to improvement of the process efficiency reaching directly the polishing and figuring process without the need for the loose abrasive lapping stage.

  2. Use of spring-roll EAP actuator applied as end-effector of a hyper-redundant robot

    Science.gov (United States)

    Errico, Gianmarco; Fava, Victor; Resta, Ferruccio; Ripamonti, Francesco

    2015-04-01

    This paper presents a hyper-redundant continuous robot used to perform work in places which humans can not reach. This type of robot is generally a bio-inspired solution, it is composed by a lot of flexible segments driven by multiple actuators and its dynamics is described by a lot degrees of freedom. In this paper a model composed of some rigid links connected to each other by revolution joint is presented. In each link a torsional spring is added in order to simulate the resistant torque between the links and the interactions among the cables and the robot during the relative rotation. Moreover a type of EAP actuator, called spring roll, is used as the end-effector of the robot. Through a suitable sensor, such as a camera, the spring roll allows to track a target and it closes the control loop on the robot to follow it.

  3. Nonlinear Control of Marine Surface Vessels

    Science.gov (United States)

    Das, Swarup; Talole, S. E.

    2018-03-01

    In the present study, a robust yaw control law design derived from nonlinear extended state observer (NESO) based nonlinear state error feedback controller (NSEFC) in conjunction with nonlinear tracking differentiator (NTD) for marine surface vessels is presented. As marine vessel operates in an environment where significant uncertainties and disturbances are present, an NESO is used to estimate the effect of the uncertainties and disturbances along with the plant states leading to a robust design through disturbance estimation and compensation. Convergence of NESO and NTD is demonstrated. The notable feature of the formulation is that to achieve robustness, accurate plant model or any characterization of the uncertainties and disturbances is not needed. Efficacy of the design is illustrated by simulation. Further, performance of the proposed design is compared with some existing controllers to showcase the effectiveness of the proposed design.

  4. Control of bacterial biofilm growth on surfaces by nanostructural mechanics and geometry

    International Nuclear Information System (INIS)

    Epstein, A K; Hochbaum, A I; Kim, Philseok; Aizenberg, J

    2011-01-01

    Surface-associated communities of bacteria, called biofilms, pervade natural and anthropogenic environments. Mature biofilms are resistant to a wide range of antimicrobial treatments and therefore pose persistent pathogenic threats. The use of surface chemistry to inhibit biofilm growth has been found to only transiently affect initial attachment. In this work, we investigate the tunable effects of physical surface properties, including high-aspect-ratio (HAR) surface nanostructure arrays recently reported to induce long-range spontaneous spatial patterning of bacteria on the surface. The functional parameters and length scale regimes that control such artificial patterning for the rod-shaped pathogenic species Pseudomonas aeruginosa are elucidated through a combinatorial approach. We further report a crossover regime of biofilm growth on a HAR nanostructured surface versus the nanostructure effective stiffness. When the 'softness' of the hair-like nanoarray is increased beyond a threshold value, biofilm growth is inhibited as compared to a flat control surface. This result is consistent with the mechanoselective adhesion of bacteria to surfaces. Therefore by combining nanoarray-induced bacterial patterning and modulating the effective stiffness of the nanoarray—thus mimicking an extremely compliant flat surface—bacterial mechanoselective adhesion can be exploited to control and inhibit biofilm growth.

  5. A Modular Approach to Model Oscillating Control Surfaces Using Navier Stokes Equations

    Science.gov (United States)

    Guruswamy, Guru P.; Lee, Henry

    2014-01-01

    The use of active controls for rotorcraft is becoming more important for modern aerospace configurations. Efforts to reduce the vibrations of helicopter blades with use of active-controls are in progress. Modeling oscillating control surfaces using the linear aerodynamics theory is well established. However, higher-fidelity methods are needed to account for nonlinear effects, such as those that occur in transonic flow. The aeroelastic responses of a wing with an oscillating control surface, computed using the transonic small perturbation (TSP) theory, have been shown to cause important transonic flow effects such as a reversal of control surface effectiveness that occurs as the shock wave crosses the hinge line. In order to account for flow complexities such as blade-vortex interactions of rotor blades higher-fidelity methods based on the Navier-Stokes equations are used. Reference 6 presents a procedure that uses the Navier-Stokes equations with moving-sheared grids and demonstrates up to 8 degrees of control-surface amplitude, using a single grid. Later, this procedure was extended to accommodate larger amplitudes, based on sliding grid zones. The sheared grid method implemented in EulerlNavier-Stokes-based aeroelastic code ENS AERO was successfully applied to active control design by industry. Recently there are several papers that present results for oscillating control surface using Reynolds Averaged Navier-Stokes (RANS) equations. References 9 and 10 report 2-D cases by filling gaps with overset grids. Reference 9 compares integrated forces with the experiment at low oscillating frequencies whereas Ref. 10 reports parametric studies but with no validation. Reference II reports results for a 3D case by modeling the gap region with a deformed grid and compares force results with the experiment only at the mid-span of flap. In Ref. II grid is deformed to match the control surface deflections at the section where the measurements are made. However, there is no

  6. ANALYSIS OF RELIABILITY OF RESERVED AUTOMATIC CONTROL SYSTEMS OF INDUSTRIAL POWER PROCESSES

    Directory of Open Access Journals (Sweden)

    V. A. Anishchenko

    2014-01-01

    Full Text Available This paper describes the comparative analysis of the main structural schemes for reserved automatic control and regulation devices of important objects of power supply with increased reliability requirements. There were analyzed schemes of passive and active doubling with control device, passive and active tripling, combined redundancy and majority redundancy according to schemes: “two from three” and “three from five”. On the results of calculations fulfilled there was made comparison of these schemes for ideal devices of built-in control and ideal majority elements. Scales of preferences of systems according to criterion of average time maximum and average probability of no-failure operation were built. These scales have variable character, depending on intervals in which there is a parameter obtained by multiplication of failure rate and time. The sequence of systems’ preferences is changing and is depending on each system failures and in moments of curves crossing of average probability of no-failure operation of systems. Analysis of calculation results showed the advantages of tripling systems and combined redundancy in reliability and this is achieved by a great amount of expenses for these systems creation. Under definite conditions the reliability of system of passive tripling is higher compared to system of active doubling. The majority schemes allow determining not only the full but also single (metrological failures. Boundary value of unreliability of built-in control device is determined, and this allows making a perfect choice between systems of active and passive redundancy.

  7. Dynamic Surface Control and Its Application to Lateral Vehicle Control

    Directory of Open Access Journals (Sweden)

    Bongsob Song

    2014-01-01

    Full Text Available This paper extends the design and analysis methodology of dynamic surface control (DSC in Song and Hedrick, 2011, for a more general class of nonlinear systems. When rotational mechanical systems such as lateral vehicle control and robot control are considered for applications, sinusoidal functions are easily included in the equation of motions. If such a sinusoidal function is used as a forcing term for DSC, the stability analysis faces the difficulty due to highly nonlinear functions resulting from the low-pass filter dynamics. With modification of input variables to the filter dynamics, the burden of mathematical analysis can be reduced and stability conditions in linear matrix inequality form to guarantee the quadratic stability via DSC are derived for the given class of nonlinear systems. Finally, the proposed design and analysis approach are applied to lateral vehicle control for forward automated driving and backward parallel parking at a low speed as well as an illustrative example.

  8. Low cost highly available digital control computer

    International Nuclear Information System (INIS)

    Silvers, M.W.

    1986-01-01

    When designing digital controllers for critical plant control it is important to provide several features. Among these are reliability, availability, maintainability, environmental protection, and low cost. An examination of several applications has lead to a design that can be produced for approximately $20,000 (1000 control points). This design is compatible with modern concepts in distributed and hierarchical control. The canonical controller element is a dual-redundant self-checking computer that communicates with a cross-strapped, electrically isolated input/output system. The input/output subsystem comprises multiple intelligent input/output cards. These cards accept commands from the primary processor which are validated, executed, and acknowledged. Each card may be hot replaced to facilitate sparing. The implementation of the dual-redundant computer architecture is discussed. Called the FS-86, this computer can be used for a variety of applications. It has most recently found application in the upgrade of San Francisco's Bay Area Rapid Transit (BART) train control currently in progress and has been proposed for feedwater control in a boiling water reactor

  9. Reliable and redundant FPGA based read-out design in the ATLAS TileCal Demonstrator

    CERN Document Server

    Åkerstedt, Henrik; The ATLAS collaboration; Drake, Gary; Anderson, Kelby; Bohm, Christian; Oreglia, Mark; Tang, Fukun

    2015-01-01

    The Tile Calorimeter at ATLAS is a hadron calorimeter based on steel plates and scintillating tiles read out by PMTs. The current read-out system uses standard ADCs and custom ASICs to digitize and temporarily store the data on the detector. However, only a subset of the data is actually read out to the counting room. The on-detector electronics will be replaced around 2023. To achieve the required reliability the upgraded system will be highly redundant. Here the ASICs will be replaced with Kintex-7 FPGAs from Xilinx. This, in addition to the use of multiple 10 Gbps optical read-out links, will allow a full read-out of all detector data. Due to the higher radiation levels expected when the beam luminosity is increased, opportunities for repairs will be less frequent. The circuitry and firmware must therefore be designed for sufficiently high reliability using redundancy and radiation tolerant components. Within a year, a hybrid demonstrator including the new read-out system will be installed in one slice of ...

  10. Quantitative analysis of Common cause failures in systems with a high level of redundancies

    International Nuclear Information System (INIS)

    Pereira Pagan, B.; Lopez Fdez-Quevedo, C.; Gomez, F.; Cuallado, G.

    1996-01-01

    The importance of common cause failures in plants with systems featuring a high level of redundancies, and the difficulty implied by the lack of data on specific KWU design plants have been taken into account right from the beginning of the PSA. for this reason it has been necessary to analyse the different methodologies by establishing a procedure based on the documentation available, studying its applicability and solving problems arising from of the lack of information needed to make reliable statistical estimates. It was finally decided to systematically use the alpha parameter method. In case where this was not possible, the modified Beta factor method was used, and if there were no data available for the type of component considered, generic alpha values were used. this process required the definition of certain criteria to maintain coherent parameter estimates. The final result shows the impact of the number of redundancies considered in the estimated failure probability or rare. This process is valid for any size of system modelled. (Author)

  11. 77 FR 28797 - Redundancy of Communications Systems: Backup Power Private Land Mobile Radio Services: Selection...

    Science.gov (United States)

    2012-05-16

    ... FEDERAL COMMUNICATIONS COMMISSION 47 CFR Parts 12 and 90 [DA 11-1838] Redundancy of Communications Systems: Backup Power Private Land Mobile Radio Services: Selection and Assignment of Frequencies, and Transition of the Upper 200 Channels in the 800 MHz Band to EA Licensing AGENCY: Federal Communications...

  12. Multi-functional surfaces with controllable wettability and water adhesion

    Science.gov (United States)

    Anastasiadis, Spiros H.; Frysali, Melani A.; Kenanakis, George; Kaklamani, Georgia; Papoutsakis, Lampros

    The design of multifunctional surfaces based on biomimetic structures has gained the interest of the scientific community. Novel multifunctional surfaces have been developed, able to alter their wetting properties in response to temperature and pH as well as light illumination, by combining proper chemistry and surface micro/nano-structuring using ultrafast (femtosecond) laser irradiation. The combination of the hierarchical surface with a ZnO and/or a responsive polymer coating results in efficient photo-active properties as well as reversible superhydrophobic / superhydrophilic surfaces in response to external stimuli. These surfaces can be optimized to exhibit high or zero water adhesion and/or controllable directionality as well. Moreover, they can be seeded with human fibroblasts to examine the cellular response on both surface roughness and surface chemistry. Acknowledgements: This research has been co-financed by the General Secretariat for Research and Technology (''ARISTEIA II'' Action, SMART-SURF) and the European Union (NFFA Europe -Grant agreement No. 654360).

  13. A Network of Local and Redundant Gene Regulation Governs Arabidopsis Seed Maturation

    Science.gov (United States)

    To, Alexandra; Valon, Christiane; Savino, Gil; Guilleminot, Jocelyne; Devic, Martine; Giraudat, Jérôme; Parcy, François

    2006-01-01

    In Arabidopsis thaliana, four major regulators (ABSCISIC ACID INSENSITIVE3 [ABI3], FUSCA3 [FUS3], LEAFY COTYLEDON1 [LEC1], and LEC2) control most aspects of seed maturation, such as accumulation of storage compounds, cotyledon identity, acquisition of desiccation tolerance, and dormancy. The molecular basis for complex genetic interactions among these regulators is poorly understood. By analyzing ABI3 and FUS3 expression in various single, double, and triple maturation mutants, we have identified multiple regulatory links among all four genes. We found that one of the major roles of LEC2 was to upregulate FUS3 and ABI3. The lec2 mutation is responsible for a dramatic decrease in ABI3 and FUS3 expression, and most lec2 phenotypes can be rescued by ABI3 or FUS3 constitutive expression. In addition, ABI3 and FUS3 positively regulate themselves and each other, thereby forming feedback loops essential for their sustained and uniform expression in the embryo. Finally, LEC1 also positively regulates ABI3 and FUS3 in the cotyledons. Most of the genetic controls discovered were found to be local and redundant, explaining why they had previously been overlooked. This works establishes a genetic framework for seed maturation, organizing the key regulators of this process into a hierarchical network. In addition, it offers a molecular explanation for the puzzling variable features of lec2 mutant embryos. PMID:16731585

  14. Patient set-up verification by infrared optical localization and body surface sensing in breast radiation therapy

    International Nuclear Information System (INIS)

    Spadea, Maria Francesca; Baroni, Guido; Riboldi, Marco; Orecchia, Roberto; Pedotti, Antonio; Tagaste, Barbara; Garibaldi, Cristina

    2006-01-01

    Background and purpose: The aim of the study was to investigate the clinical application of a technique for patient set-up verification in breast cancer radiotherapy, based on the 3D localization of a hybrid configuration of surface control points. Materials and methods: An infrared optical tracker provided the 3D position of two passive markers and 10 laser spots placed around and within the irradiation field on nine patients. A fast iterative constrained minimization procedure was applied to detect and compensate patient set-up errors, through the control points registration with reference data coming from treatment plan (markers reference position, CT-based surface model). Results: The application of the corrective spatial transformation estimated by the registration procedure led to significant improvement of patient set-up. Median value of 3D errors affecting three additional verification markers within the irradiation field decreased from 5.7 to 3.5 mm. Errors variability (25-75%) decreased from 3.2 to 2.1 mm. Laser spots registration on the reference surface model was documented to contribute substantially to set-up errors compensation. Conclusions: Patient set-up verification through a hybrid set of control points and constrained surface minimization algorithm was confirmed to be feasible in clinical practice and to provide valuable information for the improvement of the quality of patient set-up, with minimal requirement of operator-dependant procedures. The technique combines conveniently the advantages of passive markers based methods and surface registration techniques, by featuring immediate and robust estimation of the set-up accuracy from a redundant dataset

  15. Control of Surface and Edge Oxidation on Phosphorene.

    Science.gov (United States)

    Kuntz, Kaci L; Wells, Rebekah A; Hu, Jun; Yang, Teng; Dong, Baojuan; Guo, Huaihong; Woomer, Adam H; Druffel, Daniel L; Alabanza, Anginelle; Tománek, David; Warren, Scott C

    2017-03-15

    Phosphorene is emerging as an important two-dimensional semiconductor, but controlling the surface chemistry of phosphorene remains a significant challenge. Here, we show that controlled oxidation of phosphorene determines the composition and spatial distribution of the resulting oxide. We used X-ray photoemission spectroscopy to measure the binding energy shifts that accompany oxidation. We interpreted these spectra by calculating the binding energy shift for 24 likely bonding configurations, including phosphorus oxides and hydroxides located on the basal surface or edges of flakes. After brief exposure to high-purity oxygen or high-purity water vapor at room temperature, we observed phosphorus in the +1 and +2 oxidation states; longer exposures led to a large population of phosphorus in the +3 oxidation state. To provide insight into the spatial distribution of the oxide, transmission electron microscopy was performed at several stages during the oxidation. We found crucial differences between oxygen and water oxidants: while pure oxygen produced an oxide layer on the van der Waals surface, water oxidized the material at pre-existing defects such as edges or steps. We propose a mechanism based on the thermodynamics of electron transfer to interpret these observations. This work opens a route to functionalize the basal surface or edges of two-dimensional (2D) black phosphorus through site-selective chemical reactions and presents the opportunity to explore the synthesis of 2D phosphorene oxide by oxidation.

  16. Design of redundant array of independent DVD libraries based on iSCSI

    Science.gov (United States)

    Chen, Yupeng; Pan, Longfa

    2003-04-01

    This paper presents a new approach to realize the redundant array of independent DVD libraries (RAID-LoIP) by using the iSCSI technology and traditional RAID algorithms. Our design reaches the high performance of optical storage system with following features: large storage size, highly accessing rate, random access, long distance of DVD libraries, block I/O storage, long storage life. Our RAID-LoIP system can be a good solution for broadcasting media asset storage system.

  17. Multiscale analysis of surface morphologies by curvelet and contourlet transforms

    International Nuclear Information System (INIS)

    Li, Linfu; Zhang, Xiangchao; Zhang, Hao; He, Xiaoying; Xu, Min

    2015-01-01

    The surface topographies of precision components are critical to their functionalities. However, it is challenging to characterize the topographies of complex surfaces, especially for structured surfaces. The wavelet families are promising for the multiscale geometry analysis of nonstochastic surfaces. The second-generation curvelet transform provides a sparse representation and good multiscale decomposition for curve singularities. However, the contourlet expansion, composed of bases oriented along various directions in multiple scales with smaller redundancy rates, has a remarkable capability of representing borderlines. In this paper they are both adopted for the characterization of surface topographies. Different components can be extracted according to their scales and morphological characteristics; as a result, the corresponding manufacturing processes and functionalities can be analyzed specifically. Numerical experiments are given to demonstrate the capabilities of these methods in sparse representation and effective extraction of geometry features of different nonstochastic surfaces. (paper)

  18. Redundancy allocation problem of a system with increasing failure rates of components based on Weibull distribution: A simulation-based optimization approach

    International Nuclear Information System (INIS)

    Guilani, Pedram Pourkarim; Azimi, Parham; Niaki, S.T.A.; Niaki, Seyed Armin Akhavan

    2016-01-01

    The redundancy allocation problem (RAP) is a useful method to enhance system reliability. In most works involving RAP, failure rates of the system components are assumed to follow either exponential or k-Erlang distributions. In real world problems however, many systems have components with increasing failure rates. This indicates that as time passes by, the failure rates of the system components increase in comparison to their initial failure rates. In this paper, the redundancy allocation problem of a series–parallel system with components having an increasing failure rate based on Weibull distribution is investigated. An optimization method via simulation is proposed for modeling and a genetic algorithm is developed to solve the problem. - Highlights: • The redundancy allocation problem of a series–parallel system is aimed. • Components possess an increasing failure rate based on Weibull distribution. • An optimization method via simulation is proposed for modeling. • A genetic algorithm is developed to solve the problem.

  19. Support surface related changes in feedforward and feedback control of standing posture.

    Science.gov (United States)

    Mohapatra, Sambit; Kukkar, Komal K; Aruin, Alexander S

    2014-02-01

    The aim of the study was to investigate the effect of different support surfaces on feedforward and feedback components of postural control. Nine healthy subjects were exposed to external perturbations applied to their shoulders while standing on a rigid platform, foam, and wobble board with eyes open or closed. Electrical activity of nine trunk and leg muscles and displacements of the center of pressure were recorded and analyzed during the time frames typical of feedforward and feedback postural adjustments. Feedforward control of posture was characterized by earlier activation of anterior muscles when the subjects stood on foam compared to a wobble board or a firm surface. In addition, the magnitude of feedforward muscle activity was the largest when the foam was used. During the feedback control, anterior muscles were activated prior to posterior muscles irrespective of the nature of surface. Moreover, the largest muscle activity was seen when the supporting surface was foam. Maximum CoP displacement occurred when subjects were standing on a rigid surface. Altering support surface affects both feedforward and feedback components of postural control. This information should be taken into consideration in planning rehabilitation interventions geared towards improvement of balance. Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. Centralized Gap Clearance Control for Maglev Based Steel-Plate Conveyance System

    Directory of Open Access Journals (Sweden)

    GUNEY, O. F.

    2017-08-01

    Full Text Available The conveyance of steel-plates is one of the potential uses of the magnetic levitation technology in industry. However, the electromagnetic levitation systems inherently show nonlinear feature and are unstable without an active control. Well-known U-shaped or E-shaped electromagnets cannot provide redundant levitation with multiple degrees of freedom. In this paper, to achieve the full redundant levitation of the steel plate, a quadruple configuration of U shaped electromagnets has been proposed. To resolve the issue of instability and attain more robust levitation, a centralized control algorithm based on a modified PID controller (I PD is designed for each degree of freedom by using the Manabe canonical polynomial technique. The model of the system is carried out using electromechanical energy conversion princi¬ples and verified by 3-D FEM analysis. An experimental bench is built up to test the system performance under trajectory tracking and external disturbance excitation. The results confirm the effectiveness of the proposed system and the control approach to obtain a full redundant levitation even in case of disturbances. The paper demonstrates the feasibility of the con¬veyance of steel plates by using the quadruple configuration of U-shaped electromagnets and shows the merits of I-PD controller both in stabilization and increased robust levitation.