WorldWideScience

Sample records for dynamic behaviour control

  1. Contribution to control of robotics structures and dynamic behaviour

    International Nuclear Information System (INIS)

    Gilliot, Jean-Marie

    1990-01-01

    The scope of this thesis is the simulation of the dynamics of complex rigid multi-body systems involved in robotics, in order to control them. In the first stage, methods for obtaining equations and models required for simulation and control purposes are proposed and discussed: - determination of constraint equations using the jacobian matrices, - elaboration of direct and inverse dynamics of manipulators. The second part of this thesis deals with the different concepts and components involved in the setting of simulation systems for Robotics Application Programs: models, emulators and the software development environment. The control algorithms are then introduced as a particular class of robotics application programs. A simulator has been developed, allowing the calculation and the visualisation of robot motions, driven by generalized torques. Some examples of control programs generating such control torques are then presented to illustrate the use of the simulator. (author) [fr

  2. Dynamic behaviours and control of fractional-order memristor-based ...

    Indian Academy of Sciences (India)

    Dynamics of fractional-order memristor circuit system and its control are investigated in this paper. With the help of stability theory of fractional-order systems, stability of its equilibrium points is analysed. Then, the chaotic behaviours are validated using phase portraits, the Lyapunov exponents and bifurcation diagrams with ...

  3. Temperature control of CMS Barrel ECAL (EB) : computational thermo-hydraulic model for dynamic behaviour, control aspects

    CERN Document Server

    Wertelaers, P

    2010-01-01

    The current design foresees a central heat exchanger followed by a controlled post heater, for all ECAL. We discuss the scheme and try to assess its performance, from a Barrel viewpoint. This is based on computational work. The coolant transfer pipes play an essential role in building a dynamical model. After some studies on the behaviour of the cooling circuit itself, a strong yet simple controller is proposed. Then, the system with feedback control is scrutinized, with emphasis on disturbance rejection. The most relevant disturbances are cooling ripple, pipe heat attack, and electronics’ switching.

  4. Static states and dynamic behaviour of charges: observation and control by scanning probe microscopy

    International Nuclear Information System (INIS)

    Ishii, Masashi

    2010-01-01

    This paper reviews charges that locally functionalize materials. Microscopic analyses and operation of charges using various scanning probe microscopy (SPM) techniques have revealed static, quasi-static/quasi-dynamic and dynamic charge behaviours. Charge-sensitive SPM has allowed for the visualization of the distribution of functionalized charges in electronic devices. When used as bit data in a memory system, the charges can be operated by SPM. The behaviour of quasi-static/quasi-dynamic charges is discussed here. In the data-writing process, spatially dispersive charges rather than a fast injection rate are introduced, but the technical problems can be solved by using nanostructures. Careful charge operations using SPM should realize a memory with a larger density than Tbit/inch 2 . Dynamic charges have been introduced in physical analyses and chemical processes. Although the observable timescale is limited by the SPM system response time of the order of several seconds, dynamics such as photon-induced charge redistributions and probe-assisted chemical reactions are observed. (topical review)

  5. Static states and dynamic behaviour of charges: observation and control by scanning probe microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ishii, Masashi, E-mail: ISHII.Masashi@nims.go.j [National Institute for Materials Science (NIMS), 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan)

    2010-05-05

    This paper reviews charges that locally functionalize materials. Microscopic analyses and operation of charges using various scanning probe microscopy (SPM) techniques have revealed static, quasi-static/quasi-dynamic and dynamic charge behaviours. Charge-sensitive SPM has allowed for the visualization of the distribution of functionalized charges in electronic devices. When used as bit data in a memory system, the charges can be operated by SPM. The behaviour of quasi-static/quasi-dynamic charges is discussed here. In the data-writing process, spatially dispersive charges rather than a fast injection rate are introduced, but the technical problems can be solved by using nanostructures. Careful charge operations using SPM should realize a memory with a larger density than Tbit/inch{sup 2}. Dynamic charges have been introduced in physical analyses and chemical processes. Although the observable timescale is limited by the SPM system response time of the order of several seconds, dynamics such as photon-induced charge redistributions and probe-assisted chemical reactions are observed. (topical review)

  6. Dynamic behaviour of CANDU reactor

    International Nuclear Information System (INIS)

    Subramanian, M.G.; Srikantiah, G.; Pai, M.A.

    1976-01-01

    Understanding of the dynamic behaviour of a reactor system in a power station is essential for evolving control stragies as well as design modifications. The dynamic behaviour of Rajasthan Atomic Power Station is studied. Mathematical models for the reactor, the steam generator and the steam drum with the natural circulation loop are developed from physical principles like conservation of mass, momentum and energy. Each of these models is then simulated on a digital computer to obtain the characteristics during transients. The models are then combined to yield a dynamic mathematical model of the system comprising the reactor, the steam generator and the steam drum and this results in a nonlinear model. Using this model, responses of the system for various disturbances like step change in the area of the steam valve, step change in the temperature of feed water are obtained and are discussed. These models could be used to devise new control laws using optimal control theory or to evaluate the performance of existing control schemes. (author)

  7. A Dynamic Behaviour Analysis on the Frequency Control Capability of Electric Vehicles

    DEFF Research Database (Denmark)

    Zarogiannis, Athanasios; Marinelli, Mattia; Træholt, Chresten

    2014-01-01

    The paper presents results of a study on the dynamic response of Electric Vehicle’s (EV) when participating in frequency control of an islanded system. The following cases were considered: when there is no EV performing frequency control, when the EV participates in primary frequency control...... and when the EV participates in both primary and secondary frequency control. Different parameters are tested in various combinations, and their influence on frequency deviation as well as power and energy provided by the EV with vehicle-to-grid (V2G) capability is shown....

  8. Dynamic Behaviour of a Population of Controlled-by-price Demand Side Resources

    DEFF Research Database (Denmark)

    Sossan, Fabrizio; Han, Xue; Bindner, Henrik W.

    2014-01-01

    It is described that controlling or shedding by price the power consumption of a population of thermostatic loads introduces in the aggregate consumption dynamic effects th at cannot be disregarded if electrical flexible demand is meant to supply power system services. It is shown that inducing...

  9. Model dynamic behaviour analysis with chaotic noise using fuzzy logic based control

    International Nuclear Information System (INIS)

    Silva, Glauco Antonio Santos da

    2002-01-01

    This work presents an application of fuzzy control on dynamical system models. It has been observed that fuzzy controllers maybe used as a good alternative to the classical PI controller, once it incorporates human line behavior. Three implication relationships were used for the fussy controllers, namely, Mamdani Min, Larsen and Takagi-Sugeno. Performance comparisons were made aiming at achieving the best performance for each model used. The PI controller was used as a minimum standard, once it has been present in the industry for many years, giving acceptable performances and some degree of reliability . Two kinds of perturbations were introduced in the models to test the controllers: a ramp and chaotic perturbations. The first one is a monotonic, standard increase of an input parameter. The second one presents non-periodicity and irregularity in such a way to be quite rough to the controllers. The chaotic signal, as an analysis tool to dynamical systems, is an interesting contribution of this work. As a general conclusion it can be said the best performance, in this work, was achieved by the Takagi-Sugeno fuzzy controller. (author)

  10. Dynamic behaviour of lagoon ecosystems

    International Nuclear Information System (INIS)

    Cioffi, F.

    2008-01-01

    The dynamic behaviour of primary producers in coastal lagoons due to change of external control parameters, phosphorous external load and maximum tidal flow rate, is investigated by using a eutrophication model. The eutrophication model allows the simulation of the temporal evolution of the concentration of the following species: a) in the water column: dissolved oxygen, vegetal organic carbon, particulate and dissolved organic carbon, dissolved phosphorous and hydrogen sulphide; b) in sediments: dissolved oxygen, particulate and dissolved organic carbon, dissolved and adsorbed phosphorous, hydrogen sulphide. The vegetal organic carbon is distinguished in three components related to the main groups of primary producers, namely eel grass, macro algae and microalgae, having different modalities of nutrient uptake and kinetics parameters depending on the S/V ratio. Diagrams representing the ecosystems dynamic response to the changes of the control parameters were constructed by simulations. The response diagrams suggest the existence of regime shifts which border different ecosystem stability ranges, characterized by the dominance of a specific group of primary producers and by different ecosystem vulnerability at summer water anoxia. A catastrophic bifurcation or abrupt regime shift, evidenced by Poincare sections obtained mapping, at a prefixed time period, the values of the concentration of the species, occurs for a critical value of the control parameter and manifests itself as an abrupt change of the dominant species from eel grass to macro algae. An analogous abrupt change from eel grass to macro algae occurs for a critical value of the tidal flowrate assumed as control parameter in simulations conducted for an assigned value of external phosphorous load.

  11. Dynamic critical behaviour and scaling

    International Nuclear Information System (INIS)

    Oezoguz, B.E.

    2001-01-01

    Traditionally the scaling is the property of dynamical systems at thermal equilibrium. In second order phase transitions scaling behaviour is due to the infinite correlation length around the critical point. In first order phase transitions however, the correlation length remains finite and a different type of scaling can be observed. For first order phase transitions all singularities are governed by the volume of the system. Recently, a different type of scaling, namely dynamic scaling has attracted attention in second order phase transitions. In dynamic scaling, when a system prepared at high temperature is quenched to the critical temperature, it exhibits scaling behaviour. Dynamic scaling has been applied to various spin systems and the validity of the arguments are shown. Firstly, in this thesis project the dynamic scaling is applied to 4-dimensional using spin system which exhibits second order phase transition with mean-field critical indices. Secondly, it is shown that although the dynamic is quite different, first order phase transitions also has a different type of dynamic scaling

  12. Control of Polymer Glass Formation Behaviour Using Molecular Diluents and Dynamic Interfaces

    Science.gov (United States)

    Mangalara, Jayachandra Hari

    The end use application of polymeric materials is mainly determined by their viscosity, thermal stability and processability. These properties are primarily determined by the segmental relaxation time (taualpha) of the polymer and its glass state modulus, which determines its glassy mechanical response. Developing design principles to obtain rational control over these properties would enable fabrication of new polymers or polymer blends with improved thermal stability, enhanced processability and better mechanical robustness of the material. Introduction of diluents and nanostructuring of the material serve as invaluable tools for altering polymers' glass transition and associated dynamic and mechanical properties. Besides providing guidelines for technologically important improvements in processability, glassy mechanical properties, and transport behavior, diluent effects and behavior of nanostructured materials can provide insights into the fundamental physics of the glass transition, for example, by elucidating the interrelation between high- and low-frequency structural relaxation processes. It has been previously suggested that there exists a similarity between how diluents and interfaces impact the glass formation behavior of the polymer, raising the possibility that the effects of these two polymer modifications may be separate manifestations of a common set of physics in glass forming polymers. Here we address several interrelated questions in the understanding of glass formation in polymer/diluent blends and nanostructured polymers. First, what is the relationship between a diluent's molecular structure and its impact on a polymer's glass formation behavior? How does this compare to the effect of interfaces? Second, how does the introduction of diluents impact the role of interfaces in modifying polymer glass formation? Third, how does the introduction of interfaces impact metrology of the polymer glass transition? Finally, we address a major open

  13. Dynamic behaviour of suction caissons

    Energy Technology Data Exchange (ETDEWEB)

    Liingaard, M.

    2006-12-15

    Offshore wind energy is a promising source of energy in the near future, and is rapidly becoming competitive with other power generating technologies. The continuous improvement in wind turbine technology means that the wind turbines have increased tremendously in both size and performance during the last 25 years. In order to reduce the costs, the overall weight of the wind turbine components is minimized, which means that the wind turbine structures become more flexible and thus more sensitive to dynamic excitation. Since the first resonance frequency of the modern offshore wind turbines is close to the excitation frequencies of the rotor system, it is of outmost importance to be able to evaluate the resonance frequencies of the wind turbine structure accurately as the wind turbines increase in size. In order to achieve reliable responses of the wind turbine structure during working loads it is necessary to account for the possibilities of dynamic effects of the soil-structure interaction. The aim of this thesis is to evaluate the dynamic soil-structure interaction of foundations for offshore wind turbines, with the intention that the dynamic properties of the foundation can be properly included in a composite structure-foundation system. The work has been focused on one particular foundation type; the suction caisson. The frequency dependent stiffness (impedance) of the suction caisson has been investigated by means of a three-dimensional coupled Boundary Element/Finite Element model, where the soil is simplified as a homogenous linear viscoelastic material. The dynamic stiffness of the suction caisson is expressed in terms of dimensionless frequencydependent coefficients corresponding to the different degrees of freedom. Comparisons with known analytical and numerical solutions indicate that the static and dynamic behaviour of the foundation are predicted accurately with the applied model. The analysis has been carried out for different combinations of the

  14. Controllability of conservative behaviours

    NARCIS (Netherlands)

    Rao, Shodhan

    2012-01-01

    In this article, we first define the class of J-conservative behaviours with observable storage functions, where J is a symmetric two-variable polynomial matrix. We then provide two main results. The first result states that if J(-xi,xi) is nonsingular, the input cardinality of a J-conservative

  15. Electric arc behaviour in dynamic magnetic fields

    International Nuclear Information System (INIS)

    Put'ko, V.F.

    2000-01-01

    The behaviour of an electric arc in different time-dependent (dynamic) magnetic fields was investigated. New possibilities were found for spatial and energy stabilisation of a discharge, for intensifying heat exchange, extending the electric arc and distributed control of electric arc plasma. Rotating, alternating and travelling magnetic fields were studied. It was found that under the effect of a relatively low frequency of variations of dynamic magnetic fields (f 1000 Hz) the arc stabilised at the axis of the discharge chamber, the pulsation level decreased and discharge stability increased. The borders between these two arc existence modes were formed by a certain critical field variation frequency the period of which was determined by the heat relaxation time of the discharge. (author)

  16. Harmonic dynamical behaviour of thallous halides

    Indian Academy of Sciences (India)

    The next is the deformation dipole model (DDM) of Karo and Hardy. [19] and rigid shell ... that the most realistic model for complete harmonic dynamical behaviour of the ..... metals, Ph.D. Thesis (Banaras Hindu University, 1971) Unpublished.

  17. Dynamic contraction behaviour of pneumatic artificial muscle

    Science.gov (United States)

    Doumit, Marc D.; Pardoel, Scott

    2017-07-01

    The development of a dynamic model for the Pneumatic Artificial Muscle (PAM) is an imperative undertaking for understanding and analyzing the behaviour of the PAM as a function of time. This paper proposes a Newtonian based dynamic PAM model that includes the modeling of the muscle geometry, force, inertia, fluid dynamic, static and dynamic friction, heat transfer and valve flow while ignoring the effect of bladder elasticity. This modeling contribution allows the designer to predict, analyze and optimize PAM performance prior to its development. Thus advancing successful implementations of PAM based powered exoskeletons and medical systems. To date, most muscle dynamic properties are determined experimentally, furthermore, no analytical models that can accurately predict the muscle's dynamic behaviour are found in the literature. Most developed analytical models adequately predict the muscle force in static cases but neglect the behaviour of the system in the transient response. This could be attributed to the highly challenging task of deriving such a dynamic model given the number of system elements that need to be identified and the system's highly non-linear properties. The proposed dynamic model in this paper is successfully simulated through MATLAB programing and validated the pressure, contraction distance and muscle temperature with experimental testing that is conducted with in-house built prototype PAM's.

  18. Dynamic behaviour of “Collapsible” concrete

    Directory of Open Access Journals (Sweden)

    Caverzan Alessio

    2015-01-01

    Full Text Available In this work a particular cement composite material for protection of structures and infrastructures against accidental actions, such as blast or impact, has been investigated. An experimental procedure has been developed in order to assess static and dynamic behaviour of energy absorbing cementitious composites. The granular cementitious composite has been studied focusing attention to compressive strength, high deformation and energy dissipation capacity which are important characteristics for an absorber material. An experimental characterization of the material behaviour under compressive static and dynamic loadings has been carried out. Different deformation velocities have been studied in order to define the material behaviour in a wide range of strain rates. The velocity range up to 0.1 m/s is investigated by means of a universal servo-hydraulic MTS 50 kN testing machine. Some preliminary results have been reported and discussed in the present work.

  19. Moment-to-moment dynamics of ADHD behaviour

    Directory of Open Access Journals (Sweden)

    Aase Heidi

    2005-08-01

    learning long behavioural sequences may ultimately lead to deficient development of verbally governed behaviour and self control. The study represents a new approach to analyzing the moment-to-moment dynamics of behaviour, and provides support for the theory that reinforcement processes are altered in ADHD.

  20. Understanding biological control of greenhouse whitefly with the parasitoid Encarsia formosa : from individual behaviour to population dynamics

    NARCIS (Netherlands)

    Roermund, van H.J.W.

    1995-01-01

    The greenhouse whitefly, Trialeurodes vaporariorum (Westwood) (Homoptera, Aleyrodidae), is a very common, highly polyphagous pest insect all over the world. Biological control of whiteflies with the parasitoid Encarsia formosa Gahan (Hymenoptera, Aphelinidae) was already applied in the 1920s in

  1. Functional coordination of muscles underlying changes in behavioural dynamics.

    Science.gov (United States)

    Vernooij, Carlijn A; Rao, Guillaume; Perdikis, Dionysios; Huys, Raoul; Jirsa, Viktor K; Temprado, Jean-Jacques

    2016-06-10

    The dynamical systems approach addresses Bernstein's degrees of freedom problem by assuming that the neuro-musculo-skeletal system transiently assembles and dismantles its components into functional units (or synergies) to meet task demands. Strikingly, little is known from a dynamical point of view about the functioning of the muscular sub-system in this process. To investigate the interaction between the dynamical organisation at muscular and behavioural levels, we searched for specific signatures of a phase transition in muscular coordination when a transition is displayed at the behavioural level. Our results provide evidence that, during Fitts' task when behaviour switches to a different dynamical regime, muscular activation displays typical signatures of a phase transition; a reorganisation in muscular coordination patterns accompanied by a peak in the variability of muscle activation. This suggests that consistent changes occur in coordination processes across the different levels of description (i.e., behaviour and muscles). Specifically, in Fitts' task, target size acts as a control parameter that induces a destabilisation and a reorganisation of coordination patterns at different levels of the neuro-musculo-skeletal system.

  2. Simulating the evolution of industries using a dynamic behavioural model

    OpenAIRE

    Kunc, Martin

    2004-01-01

    Investment decisions determine that not only the evolution of industries is hard to forecast with certainty but also industries may have different dynamic behaviour and evolutionary paths. In this paper we present a behavioural framework to simulate the evolution of industries. Two factors determine the dynamic behaviour of an industry: managerial decision-making and the interconnected set of resources. Managerial decision-making significantly affects the dynamic behaviour of firms. Bounded r...

  3. Investigations into the dynamic behaviour of finned tube heat exchangers

    International Nuclear Information System (INIS)

    Sandbrink, J.; Stegemann, D.

    1981-01-01

    Atmospheric disturbances due to thunder storms, side wind effects on the shell or ground inversion can impair the heat dissipation of a cooling tower. These effects react on the overall power plant, which is reflected in the varied electrical output. This uncontrolled behaviour has been investigated in detail for the case of a boiling water reactor nuclear power station with indirect natural draught dry cooling and compared with controlled performance. A computer model, which has been checked out by means of experimental investigations on three different types of tube, is presented to describe the dynamic behaviour of finned tube heat exchangers. (orig.) [de

  4. Resetting dynamic behaviour of pipework systems

    International Nuclear Information System (INIS)

    Gaudin, M.

    1997-01-01

    Resetting models is applied to electricity generating plant pipework systems. A frequency approach to the problem is made in an original way thanks to the use of precise dynamic rigidity matrices. The method assumes two kinds of unknown: the usually processed mechanical characteristics (Young's Modulus, density etc.) and new resetting parameters acting on the dynamic behaviour of unknown connections. As the latter have a very wide range of possible variation, they benefit from a change of variable which allows the assumptions formulated to be complied with. The minimized cost function is based on a error in load. The frequencies required for building it are automatically selected thanks to different tests on measurements. Minimization uses a sensitivity technique linked with a method of least standard squares. The method has been programmed in Fortran 90 within the CIRCUS code and tried out on various examples which were simulated and sound effects cases as well as an actual case. (author)

  5. The dynamical behaviour of SS 433

    International Nuclear Information System (INIS)

    Collins, G.W. II

    1985-01-01

    In this paper a dynamical formalism is developed for describing the motion of a distorted object moving under the influence of the gravitational fields present in a close binary system. The object is assumed to be centred about one of the components and to have a form or shape sustained by axial forces such as rotation in addition to tides generated by the companion. Although such a shape will not be temporally constant, the moments of inertia are expressible in terms of the canonical coordinates of the problem and vary in a periodic manner. The dynamical behaviour of this 'elastic' body can be expressed in terms of periodic motion analogous to that found in a rigid body. The details of the resultant motion in turn places constraints on the nature of the components of the system. (author)

  6. Vehicle Dynamics and Control

    CERN Document Server

    Rajamani, Rajesh

    2012-01-01

    Vehicle Dynamics and Control provides a comprehensive coverage of vehicle control systems and the dynamic models used in the development of these control systems. The control system applications covered in the book include cruise control, adaptive cruise control, ABS, automated lane keeping, automated highway systems, yaw stability control, engine control, passive, active and semi-active suspensions, tire-road friction coefficient estimation, rollover prevention, and hybrid electric vehicle. In developing the dynamic model for each application, an effort is made to both keep the model simple enough for control system design but at the same time rich enough to capture the essential features of the dynamics. A special effort has been made to explain the several different tire models commonly used in literature and to interpret them physically. In the second edition of the book, chapters on roll dynamics, rollover prevention and hybrid electric vehicles have been added, and the chapter on electronic stability co...

  7. Control of dynamical localization

    International Nuclear Information System (INIS)

    Gong Jiangbin; Woerner, Hans Jakob; Brumer, Paul

    2003-01-01

    Control over the quantum dynamics of chaotic kicked rotor systems is demonstrated. Specifically, control over a number of quantum coherent phenomena is achieved by a simple modification of the kicking field. These include the enhancement of the dynamical localization length, the introduction of classical anomalous diffusion assisted control for systems far from the semiclassical regime, and the observation of a variety of strongly nonexponential line shapes for dynamical localization. The results provide excellent examples of controlled quantum dynamics in a system that is classically chaotic and offer opportunities to explore quantum fluctuations and correlations in quantum chaos

  8. Investigation of fused silica dynamic behaviour

    International Nuclear Information System (INIS)

    Malaise, F.; Chevalier, J.M.; Bertron, I.; Malka, F.

    2006-01-01

    The survivability of the fused silica shields to shrapnel impacts is a key factor for the affordable operation of the intense laser irradiation future facility Laser Mega Joule (LMJ). This paper presents experimental data and computational modelling for LMJ fused silica upon shock wave loading and unloading. Gas-gun flyer plate impact and explosively driven tests have been conducted to investigate the dynamic behaviour of this material. Hugoniot states and the Hugoniot Elastic Limit of LMJ fused silica have been obtained. These experimental data are useful for determining some constitutive model constants of the 'Crack-Model', a continuum tensile and compressive failure model with friction based. This model has been improved by taking into account nonlinear elasticity. The numerical results obtained by performing computations of the previous tests and some ballistic impact tests are discussed. The numerical comparisons with the experimental data show good agreement. Further developments to simulate the permanent densification and the solid-to-solid phase transformation of fused silica are required. (authors)

  9. Controlling Uncertain Dynamical Systems

    Indian Academy of Sciences (India)

    Author Affiliations. N Ananthkrishnan1 Rashi Bansal2. Head, CAE Analysis & Design Zeus Numerix Pvt Ltd. M-03, SINE, IIT Bombay Powai Mumbai 400076, India. MTech (Aerospace Engineering) with specialization in Dynamics & Control from IIT Bombay.

  10. Accounting control and organizational behaviour

    CERN Document Server

    Otley, David

    1987-01-01

    This book goes beyond the material usually included in traditional management accounting texts and provides both managers and management accountants with a simple guide to the major issues involved in developing and using accounting systems for management control. Attention is focused particularly on budgetary control systems because these form the basis for management control in most organisation of any size.

  11. Dynamic Systems and Control Engineering

    International Nuclear Information System (INIS)

    Kim, Jong Seok

    1994-02-01

    This book deals with introduction of dynamic system and control engineering, frequency domain modeling of dynamic system, temporal modeling of dynamic system, typical dynamic system and automatic control device, performance and stability of control system, root locus analysis, analysis of frequency domain dynamic system, design of frequency domain dynamic system, design and analysis of space, space of control system and digital control system such as control system design of direct digital and digitalization of consecutive control system.

  12. Dynamic Systems and Control Engineering

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jong Seok

    1994-02-15

    This book deals with introduction of dynamic system and control engineering, frequency domain modeling of dynamic system, temporal modeling of dynamic system, typical dynamic system and automatic control device, performance and stability of control system, root locus analysis, analysis of frequency domain dynamic system, design of frequency domain dynamic system, design and analysis of space, space of control system and digital control system such as control system design of direct digital and digitalization of consecutive control system.

  13. Fractional Dynamics and Control

    CERN Document Server

    Machado, José; Luo, Albert

    2012-01-01

    Fractional Dynamics and Control provides a comprehensive overview of recent advances in the areas of nonlinear dynamics, vibration and control with analytical, numerical, and experimental results. This book provides an overview of recent discoveries in fractional control, delves into fractional variational principles and differential equations, and applies advanced techniques in fractional calculus to solving complicated mathematical and physical problems.Finally, this book also discusses the role that fractional order modeling can play in complex systems for engineering and science. Discusses how fractional dynamics and control can be used to solve nonlinear science and complexity issues Shows how fractional differential equations and models can be used to solve turbulence and wave equations in mechanics and gravity theories and Schrodinger’s equation  Presents factional relaxation modeling of dielectric materials and wave equations for dielectrics  Develops new methods for control and synchronization of...

  14. Dynamic behaviour of prestressed concrete bridges

    International Nuclear Information System (INIS)

    Javor, T.

    1982-01-01

    The paper presents the results of experimental research of dynamic effects on prestressed concrete bridges in dynamic load tests using testing vehicles. The bridges were passed over in both directions at various speeds also running over an artificial unevenness to produce impact loads. From investigated bridges are shown the dynamic quantities such as dynamic coefficients, natural frequency, logarithmical decrement of damping, etc. (orig.) [de

  15. The dynamic behaviour of a railway mine vehicle

    Energy Technology Data Exchange (ETDEWEB)

    van Manen, P.; Brickle, B.V.

    1983-06-01

    The paper describes a mathematical model of a railway mine vehicle which is capable of predicting its dynamic behaviour in response to track inputs. The predictions of the model have been compared with the results of tests carried out on a new high speed mine vehicle and the correlation shown is good. The model yields frequency response information for the vehicle and may be used to simulate dynamic behaviour in response to track irregularities. (4 refs.)

  16. Integrating human behaviour dynamics into flood disaster risk assessment

    Science.gov (United States)

    Aerts, J. C. J. H.; Botzen, W. J.; Clarke, K. C.; Cutter, S. L.; Hall, J. W.; Merz, B.; Michel-Kerjan, E.; Mysiak, J.; Surminski, S.; Kunreuther, H.

    2018-03-01

    The behaviour of individuals, businesses, and government entities before, during, and immediately after a disaster can dramatically affect the impact and recovery time. However, existing risk-assessment methods rarely include this critical factor. In this Perspective, we show why this is a concern, and demonstrate that although initial efforts have inevitably represented human behaviour in limited terms, innovations in flood-risk assessment that integrate societal behaviour and behavioural adaptation dynamics into such quantifications may lead to more accurate characterization of risks and improved assessment of the effectiveness of risk-management strategies and investments. Such multidisciplinary approaches can inform flood-risk management policy development.

  17. Hybrid Predictive Control for Dynamic Transport Problems

    CERN Document Server

    Núñez, Alfredo A; Cortés, Cristián E

    2013-01-01

    Hybrid Predictive Control for Dynamic Transport Problems develops methods for the design of predictive control strategies for nonlinear-dynamic hybrid discrete-/continuous-variable systems. The methodology is designed for real-time applications, particularly the study of dynamic transport systems. Operational and service policies are considered, as well as cost reduction. The control structure is based on a sound definition of the key variables and their evolution. A flexible objective function able to capture the predictive behaviour of the system variables is described. Coupled with efficient algorithms, mainly drawn from the area of computational intelligence, this is shown to optimize performance indices for real-time applications. The framework of the proposed predictive control methodology is generic and, being able to solve nonlinear mixed-integer optimization problems dynamically, is readily extendable to other industrial processes. The main topics of this book are: ●hybrid predictive control (HPC) ...

  18. Behaviour of Soil Subjected to Dynamic Loads

    DEFF Research Database (Denmark)

    Bødker, L.

    1998-01-01

    foundations, and hence it is necessary to know the deformation properties for the soil at very low strain level. The main topic of the project is to increase the knowledge of the behaviour of Danish soils at small strain levels and to extend the laboratory facilities to deal with testing at small strains....... The soil behaviour at very small strain levels is non-linear, and the most common testing technique for this situation is the resonant column technique. One of the aims of this project is to install, check, get familiar with and perform tests on different kinds of Danish soils in a new Drnevich...... Longitudinal-Torsional Resonant Column apparatus placed at the Soil Mechanics Laboratory at Aalborg University. Another, but quite new technique for small strain testing to determine the maximum shear modulus, Gmax, is the bender element technique, and as part of the project this technique has also been...

  19. Dynamic behaviour of a CAREM type reactor

    International Nuclear Information System (INIS)

    Abbate, P.; Doval, A.

    1990-01-01

    As complement to CAREM reactor design studies, behaviour analysis were made in a non-stationary regime, with the aim of developing plant systems and determining process variables variation ranges, characteristic of normal operating conditions, specifying alarm values for different variables, as well as for operating policies. Transient accidental scenes analysis were made, concluding that reactor characteristics provide security, maintaining the core integrity. (Author) [es

  20. Dynamical systems examples of complex behaviour

    CERN Document Server

    Jost, Jürgen

    2005-01-01

    Our aim is to introduce, explain, and discuss the fundamental problems, ideas, concepts, results, and methods of the theory of dynamical systems and to show how they can be used in speci?c examples. We do not intend to give a comprehensive overview of the present state of research in the theory of dynamical systems, nor a detailed historical account of its development. We try to explain the important results, often neglecting technical re?nements 1 and, usually, we do not provide proofs. One of the basic questions in studying dynamical systems, i.e. systems that evolve in time, is the construction of invariants that allow us to classify qualitative types of dynamical evolution, to distinguish between qualitatively di?erent dynamics, and to studytransitions between di?erent types. Itis also important to ?nd out when a certain dynamic behavior is stable under small perturbations, as well as to understand the various scenarios of instability. Finally, an essential aspect of a dynamic evolution is the transformat...

  1. Moderators of the intention-behaviour and perceived behavioural control-behaviour relationships for leisure-time physical activity

    Directory of Open Access Journals (Sweden)

    Godin Gaston

    2008-02-01

    Full Text Available Abstract Background Intention is a key determinant of action. However, there is a gap between intention and behavioural performance that remains to be explained. Therefore, the aim of this study was to identify moderators of the intention-behaviour and perceived behavioural control (PBC- behaviour relationships for leisure-time physical activity. Method This was tested in reference to Ajzen's Theory of Planned Behaviour. A sample of 300 volunteers, 192 women and 108 men, aged 18 to 55, participated in the study. At baseline, the participants completed a self-administrated psychosocial questionnaire assessing Ajzen's theory variables (i.e., intention and perceived behavioural control. The behavioural measure was obtained by mail three months later. Results Multiple hierarchical regression analyses indicated that age and annual income moderated the intention-behaviour and PBC-behaviour relationships. However, in the final model predicting behaviour (R2 = .46, only the interaction term of PBC by annual income (β = .24, p = 0.0003 significantly contributed to the prediction of behaviour along with intention (β = .49, p = 0.0009 and past behaviour (β = .44, p Conclusion Physical activity promotion programs would benefit not only from focusing on increasing the intention of low intenders, but also from targeting factors that moderate the perceived behavioural control-behaviour relationships.

  2. Dynamic behaviour of the high confinement mode of fusion plasmas

    International Nuclear Information System (INIS)

    Zohm, H.

    1995-05-01

    This paper describes the dynamic behaviour of the High Confinement mode (H-mode) of fusion plasmas, which is one of the most promising regimes of enhanced energy confinement in magnetic fusion research. The physics of the H-mode is not yet fully understood, and the detailed behaviour is complex. However, we establish a simple physics picture of the phenomenon. Although a first principles theory of the anomalous transport processes in a fusion plasma has not yet been given, we show that within the picture developed here, it is possible to describe the dynamic behaviour of the H-mode, namely the dynamics of the L-H transition and the occurrence of edge localized modes (ELMs). (orig.)

  3. Dynamical behaviour at the Onset of Chaos

    Energy Technology Data Exchange (ETDEWEB)

    Anania, G

    1988-09-15

    Power-law divergence of nearby trajectories on the Feigenbaum attractor is discussed in terms of the algebraic index ..beta.. A statistical analysis is performed by following a multifractal approach. As a result, a fluctuating spectrum h(..beta.. is found, whose complete characterization requires the introduction of a generalized ''multispectral'' analysis. A simple model of period-doubling is extensively discussed, allowing to clarify many details of the related problems. A similar approach is expected to work in generic transitions towards chaotic behaviour.

  4. Static and dynamic behaviour of antiferromagnetic linear chains

    International Nuclear Information System (INIS)

    Henkens, L.S.J.M.

    1977-01-01

    This thesis deals with an experimental study of the static and dynamic behaviour of s=1/2 heisenberg antiferromagnetic linear chains in the temperature range of 0,05K 4 , CuSeO 4 .5H 2 O, and CuBeF 4 .5H 2 O, all of which are isomorphic salts

  5. Dynamic behaviour of rotary lip seal

    Directory of Open Access Journals (Sweden)

    El gadari M.

    2014-01-01

    Full Text Available We report on the dynamic behavior of a rotary lip seal by considering the interaction between lip, film and shaft roughness assumed to have a periodic form. The nonlinearities of stiffness and viscosity of the film are taken into account in a mass-spring-dumper model. Using the harmonic balance method, analytical prediction of the lip displacement is obtained, the frequency response is provided and the effect of the shaft undulation on the amplitude jumps of the lip displacement and on the film thickness fluctuations are discussed. The results have direct applications in reducing leakage that may occur between a smooth lip seal and a rough shaft.

  6. Comparison of brief dynamic and cognitive-behavioural therapies in avoidant personality disorder

    NARCIS (Netherlands)

    Emmelkamp, Paul M. G.; Benner, Ank; Kuipers, Antoinette; Feiertag, Guus A.; Koster, Harrie C.; van Apeldoorn, Franske J.

    Background There is a paucity of controlled trials examining the effectiveness of individual psychotherapy in personality disorders, especially in patients with cluster C disorders. Aims To compare the effectiveness of brief dynamic therapy and cognitive-behavioural therapy as out-patient treatment

  7. Dynamics of nonlinear feedback control

    NARCIS (Netherlands)

    Snippe, H.P.; Hateren, J.H. van

    Feedback control in neural systems is ubiquitous. Here we study the mathematics of nonlinear feedback control. We compare models in which the input is multiplied by a dynamic gain (multiplicative control) with models in which the input is divided by a dynamic attenuation (divisive control). The gain

  8. Modeling and dynamic behaviour of hydropower plants

    CERN Document Server

    Kishor, Nand

    2017-01-01

    This book presents a systematic approach to mathematical modeling of different configurations of hydropower plants over four sections - modeling and simulation approaches; control of hydropower plants; operation and scheduling of hydropower plants, including pumped storage; and special features of small hydropower plants.

  9. Method for calculation of the dynamic behaviour of permanent-magnet synchronous machines controlled by a thyristor-based softstarter; Berechnungsmethode zur Bestimmung des dynamischen Verhaltens von permanentmagneterregten Synchronmaschinen am Drehstromsteller

    Energy Technology Data Exchange (ETDEWEB)

    Benecke, Marcel; Lindemann, Andreas [Magdeburg Univ. (Germany). Inst. fuer Elektrische Energiesysteme; Griepentrog, Gerd [Siemens AG (Germany). Corporate Technology CT T DE

    2011-07-01

    Permanentmagnet synchronous machines (PMSM) show lower losses compared to induction machines (IM) due to the lack of rotor losses which are typical only for IM. Hence, for many applications with a fixed rotational speed such as fans or pumps the PMSM would be a good choice in case the PMSM is directly connected to the grid without any converter in between at nominal speed. This would be an optimal solution with respect to efficiency and losses. Because the PMSM is not able to speed up when directly connected to the grid, it has normally to be started using a frequency converter or it has to be equipped with a start-up short-circuit cage which would develop an asynchronous torque. A cost effective alternative is to use AC voltage controller or softstarter based on thyristors to speed up the PMSM and bridge the AC voltage controller once the PMSM has reached nominal speed. This paper presents a calculation method to predict the dynamic behaviour of a PMSM when fed by a thyristor-based AC voltage controller. (orig.)

  10. Dynamic of radionuclides behaviour in forest soils

    International Nuclear Information System (INIS)

    Ruehm, W.; Steiner, M.; Wirth, E.; Dvornik, A.; Zhuchenko, T.A.; Kliashtorin, A.; Rafferty, B.; Shaw, G.; Kuchma, N.

    1996-01-01

    Within the research project ECP-5, the dynamics of radionuclides in automorphic forest soils within the 30-km-zone of Chernobyl and of hydromorphic forest soils in Belarus have been investigated. In upland forest soils, the lower layers of the organic horizons are characterized by the highest residence times for radiocesium and represent the largest pool for all radionuclides investigated. According to a preliminary estimate, radiocesium is more mobile compared to 125 Sb, which in turn migrates faster than 60 Co, 144 Ce, and 154 Eu. 106 Ru shows the lowest mobility. With regard to radiocesium, hydromorphic soils exhibit migration rates and transfer factors from soil to trees, which by far exceed those in automorphic soils. Based on a two-component quasi-diffusional model the average bias of 137 Cs in mesotrophic swamp soils was predicted. The activity concentrations of U, Pu, and Cs suggest that U and Pu were originally deposited as hot particles and that U is naturally accumulated in organic horizons

  11. Dynamic behaviour of FBR fuel pin bundles

    International Nuclear Information System (INIS)

    Martin, P.H.; Van Dorsselaere, J.P.; Ravenet, A.

    1990-01-01

    A programme of shock tests on a fast neutron reactor subassembly model (SPX1 geometry) including a complete bundle of fuel pins (dummy elements) is being carried out in the BELIER test facility at Cadarache. The purpose of these tests is: to determine the distribution of dynamic forces applied to the fuel rod clads under the impact conditions encountered in a reactor during a earthquake; to reduce as much as possible the conservatism of the methods presently used for the calculation of those forces. The test programme, now being completed, consists of the following steps: impacts on the mock-up in air with an non-compact bundle (situation of the subassembly at beginning of life (BOL) with clearances within the bundle); impacts under the same conditions but with fluid (water) in the subassembly; impacts on the mock-up in air and with a compacted bundle (simulating the conditions of an end-of-life (EOL) bundle with no clearance within the bundle). The accelerations studied in these tests cover the range encountered in design calculations for the subassembly frequencies in beam mode. (author)

  12. Optimal control of tokamak and stellarator plasma behaviour

    International Nuclear Information System (INIS)

    Rastovic, Danilo

    2007-01-01

    The control of plasma transport, laminar and turbulent, is investigated, using the methods of scaling, optimal control and adaptive Monte Carlo simulations. For this purpose, the asymptotic behaviour of kinetic equation is considered in order to obtain finite-dimensional invariant manifolds, and in this way the finite-dimensional theory of control can be applied. We imagine the labyrinth of open doors and after applying self-similarity, the motion moved through all the desired doors in repeatable ways as Brownian motions. We take local actions for each piece of contractive ergodic motion, and, after self-organization in adaptive invariant measures, the optimum movement of particles is obtained according to the principle of maximum entropy. This is true for deterministic and stochastic cases that serve as models for plasma dynamics

  13. Factors Relating to Staff Attributions of Control over Challenging Behaviour

    Science.gov (United States)

    Dilworth, Jennifer A.; Phillips, Neil; Rose, John

    2011-01-01

    Background: Previous research has suggested that severity of intellectual disability (ID) and topography of behaviour may influence staff causal attributions regarding challenging behaviour. Subsequently, these causal attributions may influence helping behaviours. This study investigated the relationship between attributions of control over…

  14. Numerical investigations of the dynamic behaviour of the DCB sample

    International Nuclear Information System (INIS)

    Stoeckl, H.

    1985-11-01

    Expericence with the wedge-loaded double cantilever beam (DCB) sample has shown that a reliable numerical simulation of measurements of the stress intensity factor is made very difficult. One tries to predict the effects associated with the occurring complications quantitatively and to interpret the dynamic behaviour of the sample as the effects of various waveforms. The problem of stability of crack propagation is discussed using a criterion provided by Cotterell. (HP) [de

  15. Classically dynamical behaviour of single particle in heavy nuclei

    International Nuclear Information System (INIS)

    Gu Jianzhong; Zhuo Yizhong; Wu Xizhen

    1998-01-01

    A detailed analysis of the classically dynamical behaviour of a nucleon in heavy nuclei in terms of the TCSM (two-center shell model) is presented. Poincare section is a convenient and reliable criterion to judge the regularity (or chaoticity) of a classical system. The numerical calculations in this work are carried out for a nucleon in 238 U. The Poincare section map and the Poincare surface of section for different conditions are presented

  16. Simulation model of dynamical behaviour of reactor fuel assemblies

    International Nuclear Information System (INIS)

    Planchard, J.

    1994-01-01

    This report briefly describes the homogenized dynamical equations of a tube bundle placed in a perfect irrotational fluid, on case of small displacements. This approach can be used to study the mechanical behaviour of fuel assemblies of PWR reactor submitted to earthquake or depressurization blow-down. The numerical calculations require to define the added mass matrix of the fuel assemblies, for which the principle of computation is presented. (author). 14 refs., 4 figs

  17. Non-monotonic behaviour in relaxation dynamics of image restoration

    International Nuclear Information System (INIS)

    Ozeki, Tomoko; Okada, Masato

    2003-01-01

    We have investigated the relaxation dynamics of image restoration through a Bayesian approach. The relaxation dynamics is much faster at zero temperature than at the Nishimori temperature where the pixel-wise error rate is minimized in equilibrium. At low temperature, we observed non-monotonic development of the overlap. We suggest that the optimal performance is realized through premature termination in the relaxation processes in the case of the infinite-range model. We also performed Markov chain Monte Carlo simulations to clarify the underlying mechanism of non-trivial behaviour at low temperature by checking the local field distributions of each pixel

  18. Dynamical behaviour of the coupled diffusion map lattice

    International Nuclear Information System (INIS)

    Wei Wang; Cerdeira, H.A.

    1993-10-01

    In this paper we report the dynamical study of a coupled diffusive map lattice with the coupling between the elements only through the bifurcation parameter of the mapping function. The diffusive process of the lattice from an initially random distribution state to a homogeneous one and the stable range of the diffusive homogeneous attractor are discussed. For various coupling strengths we find that there are several types of spatio-temporal structures. In addition, the evolution of the lattice into chaos is studied and a largest Lyapunov exponent is used to characterize the dynamical behaviour. (author). 22 refs, 9 figs

  19. Controlling Strange Attractor in Dynamics

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A nonlinear system which exhibits a strange attractor is considered, with the goal of illustrating how to control the chaotic dynamical system and to obtain a desired attracting periodic orbit by the OGY control algorithm.

  20. Dynamics of nonlinear feedback control

    OpenAIRE

    Snippe, H.P.; Hateren, J.H. van

    2007-01-01

    Feedback control in neural systems is ubiquitous. Here we study the mathematics of nonlinear feedback control. We compare models in which the input is multiplied by a dynamic gain (multiplicative control) with models in which the input is divided by a dynamic attenuation (divisive control). The gain signal (resp. the attenuation signal) is obtained through a concatenation of an instantaneous nonlinearity and a linear low-pass filter operating on the output of the feedback loop. For input step...

  1. Behaviour as a Lever of Ecological Transition? Understanding and Acting on Individual Behaviour and Collective Dynamics

    International Nuclear Information System (INIS)

    Martin, Solange; Gaspard, Albane

    2017-01-01

    Beyond broad policy declarations, the implementation of ecological transition - which consists mainly in curbing consumption of energy and raw materials in our societies - requires substantial behavioural change at the collective, but also, quite obviously, the individual level. Yet, though there is general consensus around the principle of embarking on the path to transition, things get more complicated when it comes to changing our practices and habits. Can we act on individual behaviour and collective dynamics in respect of this particular aim of ecological transition, and, if so, how are we to go about it? Solange Martin and Albane Gaspard have examined this question for the French Environment and Energy Management Agency (ADEME) and offer us the fruit of their labours here. They show, for example, how the social and human sciences help to understand behaviour both at the individual level and in its collective dimensions, and they outline different possible lines of action to modify it. But, given the entanglement between various levels, it is essential, if we are to act effectively on behaviour, to combine approaches, tools and actors, and to analyse and understand social practices thoroughly before implementing political projects or measures

  2. Parenting behaviour and adolescent behavioural and emotional problems: The role of self-control

    NARCIS (Netherlands)

    Finkenauer, C.; Engels, R.C.M.E.; Baumeister, R.F.

    2005-01-01

    Cross-sectional data from 1359 boys and girls aged 10-14 years investigated whether parenting behaviours are directly or indirectly (through building self-control) associated with emotional (depression, stress, low self-esteem) and behavioural (delinquency, aggression) problems among adolescents.

  3. Hybrid dynamical systems observation and control

    CERN Document Server

    Defoort, Michael

    2015-01-01

    This book is a collection of contributions defining the state of current knowledge and new trends in hybrid systems – systems involving both continuous dynamics and discrete events – as described by the work of several well-known groups of researchers. Hybrid Dynamical Systems presents theoretical advances in such areas as diagnosability, observability and stabilization for various classes of system. Continuous and discrete state estimation and self-triggering control of nonlinear systems are advanced. The text employs various methods, among them, high-order sliding modes, Takagi–Sugeno representation and sampled-data switching to achieve its ends. The many applications of hybrid systems from power converters to computer science are not forgotten; studies of flexible-joint robotic arms and – as representative biological systems – the behaviour of the human heart and vasculature, demonstrate the wide-ranging practical significance of control in hybrid systems. The cross-disciplinary origins of study ...

  4. Dynamic space charge behaviour in polymeric DC cables

    DEFF Research Database (Denmark)

    Rasmussen, Claus Nygaard; Holbøll, Joachim; Henriksen, Mogens

    2002-01-01

    The use of extruded insulation for DC cables involves a risk of local electric field enhancement, caused by a space charge build-up within the dielectric. In this work, the theory of charge generation and transport in polymers is applied in a numerical computer model in order to predict...... the formation and transport of space charges in a polymeric dielectric. The model incorporates the processes of field assisted electron-hole pair generation from impurity atoms, trapping and charge injection at the electrodes. Its aim has been to study the field- and temperature dependent dynamic behaviour...

  5. Dynamics and control in nuclear power stations

    International Nuclear Information System (INIS)

    Butterfield, M.H.

    1992-01-01

    This volume presents a wide view of aspects of control of nuclear power stations by taking into consideration the plant as a whole and the protection systems employed therein. Authors with worldwide experience consider all aspects of dynamics and control in the context of both fast and thermal power stations. The topics discussed include the methods of development and applications within the analysis of plant behaviour, the validation of mathematical models, plant testing, and the design and implementation of controls. There are 27 papers all of which are indexed separately; steady states and model evolution (5 papers), control and protection systems (5 papers), transients (7 papers), testing and data (3 papers), model validation (6 papers) and commissioning and operation (1 paper). (author)

  6. Choreographies and Behavioural Contracts on the Way to Dynamic Updates

    Directory of Open Access Journals (Sweden)

    Mario Bravetti

    2014-11-01

    Full Text Available We survey our work on choreographies and behavioural contracts in multiparty interactions. In particular theories of behavioural contracts are presented which enable reasoning about correct service composition (contract compliance and service substitutability (contract refinement preorder under different assumptions concerning service communication: synchronous address or name based communication with patient non-preemptable or impatient invocations, or asynchronous communication. Correspondingly relations between behavioural contracts and choreographic descriptions are considered, where a contract for each communicating party is, e.g., derived by projection. The considered relations are induced as the maximal preoders which preserve contract compliance and global traces: we show maximality to hold (permitting services to be discovered/substituted independently for each party when contract refinement preorders with all the above asymmetric communication means are considered and, instead, not to hold if the standard symmetric CCS/pi-calculus communication is considered (or when directly relating choreographies to behavioral contracts via a preorder, no matter the communication mean. The obtained maximal preorders are then characterized in terms of a new form of testing, called compliance testing, where not only tests must succeed but also the system under test (thus relating to controllability theory, and compared with classical preorders such as may/must testing, trace inclusion, etc. Finally, recent work about adaptable choreographies and behavioural contracts is presented, where the theory above is extended to update mechanisms allowing choreographies/contracts to be modified at run-time by internal (self-adaptation or external intervention.

  7. Dynamic PID loop control

    International Nuclear Information System (INIS)

    Pei, L.; Klebaner, A.; Theilacker, J.; Soyars, W.; Martinez, A.; Bossert, R.; DeGraff, B.; Darve, C.

    2011-01-01

    The Horizontal Test Stand (HTS) SRF Cavity and Cryomodule 1 (CM1) of eight 9-cell, 1.3GHz SRF cavities are operating at Fermilab. For the cryogenic control system, how to hold liquid level constant in the cryostat by regulation of its Joule-Thompson JT-valve is very important after cryostat cool down to 2.0 K. The 72-cell cryostat liquid level response generally takes a long time delay after regulating its JT-valve; therefore, typical PID control loop should result in some cryostat parameter oscillations. This paper presents a type of PID parameter self-optimal and Time-Delay control method used to reduce cryogenic system parameters oscillation.

  8. Stochastic dynamics and control

    CERN Document Server

    Sun, Jian-Qiao; Zaslavsky, George

    2006-01-01

    This book is a result of many years of author's research and teaching on random vibration and control. It was used as lecture notes for a graduate course. It provides a systematic review of theory of probability, stochastic processes, and stochastic calculus. The feedback control is also reviewed in the book. Random vibration analyses of SDOF, MDOF and continuous structural systems are presented in a pedagogical order. The application of the random vibration theory to reliability and fatigue analysis is also discussed. Recent research results on fatigue analysis of non-Gaussian stress proc

  9. Serotoninergic regulation of emotional and behavioural control processes.

    NARCIS (Netherlands)

    Cools, R.; Roberts, A.C.; Robbins, T.W.

    2008-01-01

    5-Hydroxytryptamine (5-HT, serotonin) has long been implicated in a wide variety of emotional, cognitive and behavioural control processes. However, its precise contribution is still not well understood. Depletion of 5-HT enhances behavioural and brain responsiveness to punishment or other aversive

  10. Dynamics of nonlinear feedback control.

    Science.gov (United States)

    Snippe, H P; van Hateren, J H

    2007-05-01

    Feedback control in neural systems is ubiquitous. Here we study the mathematics of nonlinear feedback control. We compare models in which the input is multiplied by a dynamic gain (multiplicative control) with models in which the input is divided by a dynamic attenuation (divisive control). The gain signal (resp. the attenuation signal) is obtained through a concatenation of an instantaneous nonlinearity and a linear low-pass filter operating on the output of the feedback loop. For input steps, the dynamics of gain and attenuation can be very different, depending on the mathematical form of the nonlinearity and the ordering of the nonlinearity and the filtering in the feedback loop. Further, the dynamics of feedback control can be strongly asymmetrical for increment versus decrement steps of the input. Nevertheless, for each of the models studied, the nonlinearity in the feedback loop can be chosen such that immediately after an input step, the dynamics of feedback control is symmetric with respect to increments versus decrements. Finally, we study the dynamics of the output of the control loops and find conditions under which overshoots and undershoots of the output relative to the steady-state output occur when the models are stimulated with low-pass filtered steps. For small steps at the input, overshoots and undershoots of the output do not occur when the filtering in the control path is faster than the low-pass filtering at the input. For large steps at the input, however, results depend on the model, and for some of the models, multiple overshoots and undershoots can occur even with a fast control path.

  11. Physiological control of behaviour in tephritid fruit flies

    International Nuclear Information System (INIS)

    Jang, Eric B.

    2000-01-01

    Studies on the behaviour of tephritid fruit flies have historically focused on the interaction of external stimuli such as temperature, semiochemicals, seasonality, etc., or the interactions of flies between and among species for a number of observed behaviours such as mating, pheromone calling and oviposition. While descriptive behaviour represent much of what we know about these pest species, less is known about the underlying physiological mechanisms which function in priming or modulation of the observed behaviour. Central to our understanding of tephritid behaviour are the multiple and often complex internal factors which are involved, and the path/mechanisms by which external stimuli result in observed behaviour. Tephritid fruit fly physiology is a vastly understudied research area which may provide important information on how peripheral receptors receive information, the transduction and coding of information centrally and how behaviour is regulated biochemically. The integration of physiology disciplines to help explain behaviour is central to the goal of developing new technology which may be useful in fruit fly control. In our laboratory, we have been studying the mechanisms of chemoreception and its link to behaviour in tephritids in such areas as olfaction, feeding, mating and oviposition. Our approach has been that tephritid behaviour can be largely influenced by their peripheral receptors which are responsible for receiving olfactory, gustatory, visual and tactile information inputs and their physiological state which controls internal modulation of behaviour. Thus, differences in behaviour between species might be explained on the basis of differences in their peripheral receptors, and the plasticity in which observed behaviour vary between the same species could very well be attributed to changes in their physiological state that are not readily apparent merely from visual observation. The importance of the physiological state in behavioural

  12. Classically dynamical behaviour of a nucleon in heavy nuclei

    International Nuclear Information System (INIS)

    Gu Jianzhong; Zhao Enguang; Zong Hongshi; Zhuo Yizhong; Wu Xizhen

    1998-01-01

    Within the framework of the two-center shell model the classically dynamical behaviour of a nucleon in heavy nuclei is investigated systematically with the change of nuclear shape parameters for the first time. It is found that as long as the nucleonic energy 0is appreciably higher than the height of the potential barrier there is a good quantum-classical correspondence of nucleonic regular (chaotic) motion. Thus, Bohigas, Giannoni and Schmit conjecture is confirmed once again. We find that the difference between the potential barrier for prolate nuclei and that for oblate ones is reponsible for the energy-dependence difference between the nucleonic chaotic dynamics for prolate nuclei and that for oblate ones. In addition, it is suggested that nuclear dissipation is shape-dependent, and strong nuclear dissipation can be expected for medium or large separations in the presence of a considerable neck deformation built on a pronounced octupole-like deformation, which provides us a dynamical understanding of nuclear shape dependence of nuclear dissipation. (orig.)

  13. Assessment of the dynamic behaviours of the ITER Vacuum Vessel

    Energy Technology Data Exchange (ETDEWEB)

    Blocki, J., E-mail: jacek.blocki@f4e.europa.eu [Fusion for Energy, Josep Pla 2, Torres Diagonal Litoral B3, 08019 Barcelona (Spain); Combescure, D. [Fusion for Energy, Josep Pla 2, Torres Diagonal Litoral B3, 08019 Barcelona (Spain); Mazzone, G. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France)

    2013-10-15

    Highlights: ► The cyclic symmetry structure with special boundary conditions has been analyzed. ► Results based on the FE solid model and on the FE shell model have been compared. ► The effect of the missing mass contained has been checked. -- Abstract: The dynamic behaviour of the ITER Vacuum Vessel (VV) under seismic loads will be assessed by carrying out the modal analysis and then by applying the response spectrum method which describes earthquake motions. The effect of the missing mass is included in this last analysis. Numerical results are based on two different Finite Element (FE) models and on three different methods by which natural frequencies and mode shapes are defined. It means, it is applied the cyclic symmetry method, the component mode synthesis method and the 360° FE model of the VV. Comparisons between obtained results for the different models and methods are presented.

  14. Dynamical behaviour of the firing in coupled neuronal system

    International Nuclear Information System (INIS)

    Wei Wang; Perez, G.; Cerdeira, H.A.

    1993-03-01

    The time interval sequences and the spatio-temporal patterns of the firings of a coupled neuronal network are investigated in this paper. For a single neuron stimulated by an external stimulus I, the time interval sequences show a low frequency firing of bursts of spikes, and reversed period-doubling cascade to a high frequency repetitive firing state as the stimulus I is increased. For two neurons coupled to each other through the firing of the spikes, the complexity of the time interval sequences becomes simple as the coupling strength increases. A network with large numbers of neurons shows a complex spatio-temporal pattern structure. As the coupling strength increases, the numbers of phase locked neurons increase and the time interval diagram shows temporal chaos and a bifurcation in the space. The dynamical behaviour is also verified by the Lyapunov exponent. (author). 17 refs, 6 figs

  15. Dynamic Controllability and Dispatchability Relationships

    Science.gov (United States)

    Morris, Paul Henry

    2014-01-01

    An important issue for temporal planners is the ability to handle temporal uncertainty. Recent papers have addressed the question of how to tell whether a temporal network is Dynamically Controllable, i.e., whether the temporal requirements are feasible in the light of uncertain durations of some processes. We present a fast algorithm for Dynamic Controllability. We also note a correspondence between the reduction steps in the algorithm and the operations involved in converting the projections to dispatchable form. This has implications for the complexity for sparse networks.

  16. Psychosocial Factors of Different Health Behaviour Patterns in Adolescents: Association with Overweight and Weight Control Behaviours

    Directory of Open Access Journals (Sweden)

    Susana M. Veloso

    2012-01-01

    Full Text Available Physical activity, nutrition, and sedentary behaviour combine to influence the risk of overweight among adolescents. This paper aims to identify psychosocial factors of different health behaviour patterns in adolescents and its association with overweight and weight control behaviours. The 3069 adolescents of both genders (average of 14.8 years old from the 2010 Portuguese survey of Health Behaviour School-Aged Children (HBSC answered the 2010 HBSC self-reported questionnaire. It used the cluster k-means (nonhierarchy method, qui-square, one-way ANOVA, and logistic regression. Three clusters with different behavioural patterns (physical activity, sedentary, and eating composed the results obtained. The sedentary group (34% had lower self-regulation, body satisfaction, health and wellness, family and classmates relationships, communication with the father than the other two groups. The active gamers (25% had a smaller BMI but used more unhealthy weight control strategies than the other two groups. The healthy group (41% was more motivated and more satisfied with school but was not different than the active gamers in most psychosocial variables. Differences were found between clusters for weight control behaviours and psychosocial variables. Different strategies for different patterns were necessary in order to promote obesity prevention and, simultaneously, target healthy lifestyle and wellbeing in adolescents.

  17. Psychosocial Factors of Different Health Behaviour Patterns in Adolescents: Association with Overweight and Weight Control Behaviours

    Science.gov (United States)

    Veloso, Susana M.; Matos, Margarida G.; Carvalho, Marina; Diniz, José A.

    2012-01-01

    Physical activity, nutrition, and sedentary behaviour combine to influence the risk of overweight among adolescents. This paper aims to identify psychosocial factors of different health behaviour patterns in adolescents and its association with overweight and weight control behaviours. The 3069 adolescents of both genders (average of 14.8 years old) from the 2010 Portuguese survey of Health Behaviour School-Aged Children (HBSC) answered the 2010 HBSC self-reported questionnaire. It used the cluster k-means (nonhierarchy method), qui-square, one-way ANOVA, and logistic regression. Three clusters with different behavioural patterns (physical activity, sedentary, and eating) composed the results obtained. The sedentary group (34%) had lower self-regulation, body satisfaction, health and wellness, family and classmates relationships, communication with the father than the other two groups. The active gamers (25%) had a smaller BMI but used more unhealthy weight control strategies than the other two groups. The healthy group (41%) was more motivated and more satisfied with school but was not different than the active gamers in most psychosocial variables. Differences were found between clusters for weight control behaviours and psychosocial variables. Different strategies for different patterns were necessary in order to promote obesity prevention and, simultaneously, target healthy lifestyle and wellbeing in adolescents. PMID:22811890

  18. A dynamic systems perspective on social cognition, problematic behaviour, and intervention in adolescence

    NARCIS (Netherlands)

    Lichtwarck-Aschoff, Anna; van Geert, Paul

    2004-01-01

    In this article we discussed a dynamic systems view on social behaviour in adolescence. Social behaviour is defined as a self-organizing attractor landscape, based on a network of proximal (i.e., direct) causes. In some cases, social development is disturbed, leading to problematic behaviour in

  19. Intrinsic motivation, norms and environmental behaviour : The dynamics of overarching goals

    NARCIS (Netherlands)

    Steg, L.; Lindenberg, S.M.; Keizer, K.

    2016-01-01

    The understanding, prediction, and encouragement of pro-environmental behaviour (i.e., behaviour that impacts the environment as little as possible) depend to a large extent on understanding the motivational dynamics of pro-environmental behaviour. In this review paper, we discuss the state of the

  20. Controlling dynamics in diatomic systems

    Indian Academy of Sciences (India)

    WINTEC

    Abstract. Controlling molecular energetics using laser pulses is exemplified for nuclear motion in two different diatomic systems. The problem of finding the optimized field for maximizing a desired quantum dynamical target is formulated using an iterative method. The method is applied for two diatomic sys- tems, HF and OH.

  1. The dynamics of success and failure: how post-behaviour evaluations relate to subsequent exercise intentions and behaviour.

    Science.gov (United States)

    Kwan, Bethany M; Bryan, Angela D; Sheeran, Paschal

    2018-01-25

    Exercise behaviour change involves multiple experiences with success and failure. The Model of Action Phases (MAP) offers a dynamic account of how success and failure influence both immediate evaluations and future decisions and actions. However, predictions from the MAP have not been formally tested. A longitudinal daily diary study was used to examine how post-behaviour evaluations of exercise success and failure influence subsequent exercise intentions and behaviour. Participants (N = 104) set exercise goals, and then kept a daily online exercise diary for four weeks. Participants self-reported exercise behaviour, affective response to exercise, self-evaluations after success or failure at following through on intentions to exercise, and intentions to exercise in the next week. Multilevel modelling revealed significant within- and between-participant relationships among post-behaviour evaluations, intentions and subsequent behaviour. Findings supported MAP-derived predictions about how success and failure at exercise are associated with feelings about exercise and the self, and inform subsequent exercise intentions and behaviour. Positive post-behaviour evaluations of success or failure may stabilise positive intentions and aid maintenance of exercise behaviour. Implications of these MAP-based findings for intervention design are discussed.

  2. Control algorithms for dynamic attenuators

    Energy Technology Data Exchange (ETDEWEB)

    Hsieh, Scott S., E-mail: sshsieh@stanford.edu [Department of Radiology, Stanford University, Stanford, California 94305 and Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States); Pelc, Norbert J. [Department of Radiology, Stanford University, Stanford California 94305 and Department of Bioengineering, Stanford University, Stanford, California 94305 (United States)

    2014-06-15

    Purpose: The authors describe algorithms to control dynamic attenuators in CT and compare their performance using simulated scans. Dynamic attenuators are prepatient beam shaping filters that modulate the distribution of x-ray fluence incident on the patient on a view-by-view basis. These attenuators can reduce dose while improving key image quality metrics such as peak or mean variance. In each view, the attenuator presents several degrees of freedom which may be individually adjusted. The total number of degrees of freedom across all views is very large, making many optimization techniques impractical. The authors develop a theory for optimally controlling these attenuators. Special attention is paid to a theoretically perfect attenuator which controls the fluence for each ray individually, but the authors also investigate and compare three other, practical attenuator designs which have been previously proposed: the piecewise-linear attenuator, the translating attenuator, and the double wedge attenuator. Methods: The authors pose and solve the optimization problems of minimizing the mean and peak variance subject to a fixed dose limit. For a perfect attenuator and mean variance minimization, this problem can be solved in simple, closed form. For other attenuator designs, the problem can be decomposed into separate problems for each view to greatly reduce the computational complexity. Peak variance minimization can be approximately solved using iterated, weighted mean variance (WMV) minimization. Also, the authors develop heuristics for the perfect and piecewise-linear attenuators which do not requirea priori knowledge of the patient anatomy. The authors compare these control algorithms on different types of dynamic attenuators using simulated raw data from forward projected DICOM files of a thorax and an abdomen. Results: The translating and double wedge attenuators reduce dose by an average of 30% relative to current techniques (bowtie filter with tube current

  3. Control algorithms for dynamic attenuators

    International Nuclear Information System (INIS)

    Hsieh, Scott S.; Pelc, Norbert J.

    2014-01-01

    Purpose: The authors describe algorithms to control dynamic attenuators in CT and compare their performance using simulated scans. Dynamic attenuators are prepatient beam shaping filters that modulate the distribution of x-ray fluence incident on the patient on a view-by-view basis. These attenuators can reduce dose while improving key image quality metrics such as peak or mean variance. In each view, the attenuator presents several degrees of freedom which may be individually adjusted. The total number of degrees of freedom across all views is very large, making many optimization techniques impractical. The authors develop a theory for optimally controlling these attenuators. Special attention is paid to a theoretically perfect attenuator which controls the fluence for each ray individually, but the authors also investigate and compare three other, practical attenuator designs which have been previously proposed: the piecewise-linear attenuator, the translating attenuator, and the double wedge attenuator. Methods: The authors pose and solve the optimization problems of minimizing the mean and peak variance subject to a fixed dose limit. For a perfect attenuator and mean variance minimization, this problem can be solved in simple, closed form. For other attenuator designs, the problem can be decomposed into separate problems for each view to greatly reduce the computational complexity. Peak variance minimization can be approximately solved using iterated, weighted mean variance (WMV) minimization. Also, the authors develop heuristics for the perfect and piecewise-linear attenuators which do not requirea priori knowledge of the patient anatomy. The authors compare these control algorithms on different types of dynamic attenuators using simulated raw data from forward projected DICOM files of a thorax and an abdomen. Results: The translating and double wedge attenuators reduce dose by an average of 30% relative to current techniques (bowtie filter with tube current

  4. Control algorithms for dynamic attenuators.

    Science.gov (United States)

    Hsieh, Scott S; Pelc, Norbert J

    2014-06-01

    The authors describe algorithms to control dynamic attenuators in CT and compare their performance using simulated scans. Dynamic attenuators are prepatient beam shaping filters that modulate the distribution of x-ray fluence incident on the patient on a view-by-view basis. These attenuators can reduce dose while improving key image quality metrics such as peak or mean variance. In each view, the attenuator presents several degrees of freedom which may be individually adjusted. The total number of degrees of freedom across all views is very large, making many optimization techniques impractical. The authors develop a theory for optimally controlling these attenuators. Special attention is paid to a theoretically perfect attenuator which controls the fluence for each ray individually, but the authors also investigate and compare three other, practical attenuator designs which have been previously proposed: the piecewise-linear attenuator, the translating attenuator, and the double wedge attenuator. The authors pose and solve the optimization problems of minimizing the mean and peak variance subject to a fixed dose limit. For a perfect attenuator and mean variance minimization, this problem can be solved in simple, closed form. For other attenuator designs, the problem can be decomposed into separate problems for each view to greatly reduce the computational complexity. Peak variance minimization can be approximately solved using iterated, weighted mean variance (WMV) minimization. Also, the authors develop heuristics for the perfect and piecewise-linear attenuators which do not require a priori knowledge of the patient anatomy. The authors compare these control algorithms on different types of dynamic attenuators using simulated raw data from forward projected DICOM files of a thorax and an abdomen. The translating and double wedge attenuators reduce dose by an average of 30% relative to current techniques (bowtie filter with tube current modulation) without

  5. A dynamic Monte Carlo study of anomalous current voltage behaviour in organic solar cells

    International Nuclear Information System (INIS)

    Feron, K.; Fell, C. J.; Zhou, X.; Belcher, W. J.; Dastoor, P. C.

    2014-01-01

    We present a dynamic Monte Carlo (DMC) study of s-shaped current-voltage (I-V) behaviour in organic solar cells. This anomalous behaviour causes a substantial decrease in fill factor and thus power conversion efficiency. We show that this s-shaped behaviour is induced by charge traps that are located at the electrode interface rather than in the bulk of the active layer, and that the anomaly becomes more pronounced with increasing trap depth or density. Furthermore, the s-shape anomaly is correlated with interface recombination, but not bulk recombination, thus highlighting the importance of controlling the electrode interface. While thermal annealing is known to remove the s-shape anomaly, the reason has been not clear, since these treatments induce multiple simultaneous changes to the organic solar cell structure. The DMC modelling indicates that it is the removal of aluminium clusters at the electrode, which act as charge traps, that removes the anomalous I-V behaviour. Finally, this work shows that the s-shape becomes less pronounced with increasing electron-hole recombination rate; suggesting that efficient organic photovoltaic material systems are more susceptible to these electrode interface effects

  6. Serotoninergic regulation of emotional and behavioural control processes.

    Science.gov (United States)

    Cools, Roshan; Roberts, Angela C; Robbins, Trevor W

    2008-01-01

    5-Hydroxytryptamine (5-HT, serotonin) has long been implicated in a wide variety of emotional, cognitive and behavioural control processes. However, its precise contribution is still not well understood. Depletion of 5-HT enhances behavioural and brain responsiveness to punishment or other aversive signals, while disinhibiting previously rewarded but now punished behaviours. Findings suggest that 5-HT modulates the impact of punishment-related signals on learning and emotion (aversion), but also promotes response inhibition. Exaggerated aversive processing and deficient response inhibition could underlie distinct symptoms of a range of affective disorders, namely stress- or threat-vulnerability and compulsive behaviour, respectively. We review evidence from studies with human volunteers and experimental animals that begins to elucidate the neurobiological systems underlying these different effects.

  7. Active Inference, homeostatic regulation and adaptive behavioural control.

    Science.gov (United States)

    Pezzulo, Giovanni; Rigoli, Francesco; Friston, Karl

    2015-11-01

    We review a theory of homeostatic regulation and adaptive behavioural control within the Active Inference framework. Our aim is to connect two research streams that are usually considered independently; namely, Active Inference and associative learning theories of animal behaviour. The former uses a probabilistic (Bayesian) formulation of perception and action, while the latter calls on multiple (Pavlovian, habitual, goal-directed) processes for homeostatic and behavioural control. We offer a synthesis these classical processes and cast them as successive hierarchical contextualisations of sensorimotor constructs, using the generative models that underpin Active Inference. This dissolves any apparent mechanistic distinction between the optimization processes that mediate classical control or learning. Furthermore, we generalize the scope of Active Inference by emphasizing interoceptive inference and homeostatic regulation. The ensuing homeostatic (or allostatic) perspective provides an intuitive explanation for how priors act as drives or goals to enslave action, and emphasises the embodied nature of inference. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  8. Theory of controlled quantum dynamics

    Energy Technology Data Exchange (ETDEWEB)

    De Martino, Salvatore; De Siena, Silvio; Illuminati, Fabrizio [Dipartimento di Fisica, Universita di Salerno, and INFN, Sezione di Napoli, Gruppo collegato di Salerno, Baronissi (Italy)

    1997-06-07

    We introduce a general formalism to obtain localized quantum wavepackets as dynamically controlled systems, in the framework of Nelson stochastic quantization. We show that in general the control is linear, and it amounts to introducing additional time-dependent terms in the potential. In this way one can construct for general systems either coherent packets following classical motion with constant dispersion, or coherent packets following classical motion whose time-dependent dispersion remains bounded for all times. We show that in the operatorial language our scheme amounts to introducing a suitable generalization to arbitrary potentials of the displacement and scaling operators that generate the coherent and squeezed states of the harmonic oscillator. (author)

  9. Dynamical behaviour of gaseous halo in a disk galaxy

    International Nuclear Information System (INIS)

    Ikeuchi, S.; Habe, A.

    1981-01-01

    Assuming that the gas in the halo of a disk galaxy is supplied from the disk as a hot gas, the authors have studied its dynamical and thermal behaviour by means of a time dependent, two-dimensional hydrodynamic code. They suppose the following boundary conditions at the disk. (i) The hot gas with the temperature Tsub(d) and the density nsub(d) is uniform at r=4-12 kpc in the disk and it is time independent. (ii) This hot gas rotates with the stellar disk in the same velocity. (iii) This hot gas can escape freely from the disk to the halo. These conditions will be verified if the filling factor of hot gas is so large as f=0.5-0.8, as proposed by McKee and Ostriker (1977). The gas motion in the halo has been studied for wider ranges of gas temperature and its density at the disk than previously studied. At the same time, the authors have clarified the observability of various types of gaseous haloes and discuss the roles of gaseous halo on the evolution of galaxies. (Auth.)

  10. SALLY, Dynamic Behaviour of Reactor Cooling Channel by Point Model

    International Nuclear Information System (INIS)

    Reiche, Chr.; Ziegenbein, D.

    1981-01-01

    1 - Nature of the physical problem solved: The dynamical behaviour of a cooling channel is calculated. Starting from an equilibrium state a perturbation is introduced into the system. That may be an outer reactivity perturbation or a change in the coolant velocity or in the coolant temperature. The neutron kinetics is treated in the framework of the one-point model. The cooling channel consists of a cladded and cooled fuel rod. The temperature distribution is taken into account as an array above a mesh of radial zones and axial layers. Heat transfer is considered in radial direction only, the thermodynamical coupling of the different layers is obtained by the coolant flow. The thermal material parameters are considered to be temperature independent. Reactivity feedback is introduced by means of reactivity coefficients for fuel, canning, and coolant. Doppler broadening is included. The first cooling cycle can be taken into account by a simple model. 2 - Method of solution: The integration of the point kinetics equations is done numerically by the P11 scheme. The system of temperature equations with constant heat resistance coefficients is solved by the method of factorization. 3 - Restrictions on the complexity of the problem: Given limits are: 10 radial fuel zones, 25 axial layers, 6 groups of delayed neutrons

  11. Laser Controlled Molecular Orientation Dynamics

    International Nuclear Information System (INIS)

    Atabek, O.

    2004-01-01

    Molecular orientation is a challenging control issue covering a wide range of applications from reactive collisions, high order harmonic generation, surface processing and catalysis, to nanotechnologies. The laser control scenario rests on the following three steps: (i) depict some basic mechanisms producing dynamical orientation; (ii) use them both as computational and interpretative tools in optimal control schemes involving genetic algorithms; (iii) apply what is learnt from optimal control to improve the basic mechanisms. The existence of a target molecular rotational state combining the advantages of efficient and post-pulse long duration orientation is shown. A strategy is developed for reaching such a target in terms of a train of successive short laser pulses applied at predicted time intervals. Each individual pulse imparts a kick to the molecule which orients. Transposition of such strategies to generic systems is now under investigation

  12. Semi-analytical approach to modelling the dynamic behaviour of soil excited by embedded foundations

    DEFF Research Database (Denmark)

    Bucinskas, Paulius; Andersen, Lars Vabbersgaard

    2017-01-01

    The underlying soil has a significant effect on the dynamic behaviour of structures. The paper proposes a semi-analytical approach based on a Green’s function solution in frequency–wavenumber domain. The procedure allows calculating the dynamic stiffness for points on the soil surface as well...... are analysed. It is determined how simplification of the numerical model affects the overall dynamic behaviour. © 2017 The Authors. Published by Elsevier Ltd....

  13. Voltage Controlled Dynamic Demand Response

    DEFF Research Database (Denmark)

    Bhattarai, Bishnu Prasad; Bak-Jensen, Birgitte; Mahat, Pukar

    2013-01-01

    Future power system is expected to be characterized by increased penetration of intermittent sources. Random and rapid fluctuations in demands together with intermittency in generation impose new challenges for power balancing in the existing system. Conventional techniques of balancing by large...... central or dispersed generations might not be sufficient for future scenario. One of the effective methods to cope with this scenario is to enable demand response. This paper proposes a dynamic voltage regulation based demand response technique to be applied in low voltage (LV) distribution feeders....... An adaptive dynamic model has been developed to determine composite voltage dependency of an aggregated load on feeder level. Following the demand dispatch or control signal, optimum voltage setting at the LV substation is determined based on the voltage dependency of the load. Furthermore, a new technique...

  14. Fuzzy control of pressurizer dynamic process

    International Nuclear Information System (INIS)

    Ming Zhedong; Zhao Fuyu

    2006-01-01

    Considering the characteristics of pressurizer dynamic process, the fuzzy control system that takes the advantages of both fuzzy controller and PID controller is designed for the dynamic process in pressurizer. The simulation results illustrate this type of composite control system is with better qualities than those of single fuzzy controller and single PID controller. (authors)

  15. Power system dynamics and control

    CERN Document Server

    Kwatny, Harry G

    2016-01-01

    This monograph explores a consistent modeling and analytic framework that provides the tools for an improved understanding of the behavior and the building of efficient models of power systems. It covers the essential concepts for the study of static and dynamic network stability, reviews the structure and design of basic voltage and load-frequency regulators, and offers an introduction to power system optimal control with reliability constraints. A set of Mathematica tutorial notebooks providing detailed solutions of the examples worked-out in the text, as well as a package that will enable readers to work out their own examples and problems, supplements the text. A key premise of the book is that the design of successful control systems requires a deep understanding of the processes to be controlled; as such, the technical discussion begins with a concise review of the physical foundations of electricity and magnetism. This is followed by an overview of nonlinear circuits that include resistors, inductors, ...

  16. Dynamic analysis of nonlinear behaviour in inertial actuators

    International Nuclear Information System (INIS)

    Borgo, M Dal; Tehrani, M Ghandchi; Elliott, S J

    2016-01-01

    Inertial actuators are devices typically used to generate the control force on a vibrating structure. Generally, an inertial actuator comprises a proof-mass suspended in a magnetic field. The inertial force due to the moving mass is used to produce the secondary force needed to control the vibration of the primary structure. Inertial actuators can show nonlinear behaviour, such as stroke saturation when driven at high input voltages. If the input voltage is beyond their limit, they can hit the end stop of the actuator casing and saturate. In this paper, the force generated by an inertial actuator is measured experimentally and numerical simulations of a linear piecewise stiffness model are carried out and compared with the results of analytical methods. First, a numerical model for a symmetric bilinear stiffness is derived and a parametric study is carried out to investigate the change of the end stop stiffness. In addition, the variation of the amplitude of the excitation is considered and a comparison is made with the analytical solution using the harmonic balance method. Finally, experimental measurements are carried out and the results are compared with simulated data to establish the accuracy of the model. (paper)

  17. Review of the dynamic behaviour of sports balls during normal and oblique impacts

    Science.gov (United States)

    Haron, Muhammad Adli; Jailani, Azrol; Abdullah, Nik Ahmad Faris Nik; Ismail, Rafis Suizwan; Rahim, Shayfull Zamree Abd; Ghazali, Mohd Fathullah

    2017-09-01

    In this paper are review of impact experiment to study the dynamic behaviour of sports ball during oblique and normal impacts. In previous studies, the investigation was done on the dynamic behaviour of a sports ball during oblique and normal impacts from experimental, numerical, and theoretical viewpoints. The experimental results are analysed and compared with the theories, in order to understand the dynamics behaviours based on the phenomenological occurrence. Throughout the experimental studies previously, there are results of dynamics behaviours examined by many researchers such as the coefficient of restitution, tangential coefficient, local deformation, dynamic impact force, contact time, angle of impact (inbound and rebound), spin rate of the ball, ball stiffness and damping coefficient which dependable of the initial or impact velocity.

  18. Design features affecting dynamic behaviour of fast reactor cores

    International Nuclear Information System (INIS)

    Kayser, G.; Gouriou, A.

    1981-06-01

    The study of dynamic response of an LMFBR to normal and accidental transients needs first of all a simulation code taking into account all the important effects. The DYN-1 code aims at this target. It represents with a sufficiently accurate meshing the core in a 20 geometry for the thermal and reactivity effects, while the kinetics of this core are calculated with a point model. The primary pool, secondary loops, steam generator are also represented, as well as the control and protective systems. We give a short description of this code. Simpler codes are sometimes good enough for parametric studies

  19. Behavioural Models of Motor Control and Short-Term Memory

    OpenAIRE

    Imanaka, Kuniyasu; Funase, Kozo; Yamauchi, Masaki

    1995-01-01

    We examined in this review article the behavioural and conceptual models of motor control and short-term memory which have intensively been investigated since the 1970s. First, we reviewed both the dual-storage model of short-term memory in which movement information is stored and a typical model of motor control which emphasizes the importance of efferent factors. We then examined two models of preselection effects: a cognitive model and a cognitive/ efferent model. Following this we reviewe...

  20. Centralised gaming models: providing optimal gambling behaviour controls

    OpenAIRE

    Griffiths, MD; Wood, RTA

    2009-01-01

    The expansion in the gaming industry and its widening attraction points to the need for ever more verifiable means of controlling problem gambling. Various strategies have been built into casino venue operations to address this, but recently, following a new focus on social responsibility, a group of experts considered the possibilities of a centralised gaming model as a more effective control mechanism for dealing with gambling behaviours.

  1. Network information analysis reveals risk perception transmission in a behaviour-influenza dynamics system.

    Science.gov (United States)

    Liao, C-M; You, S-H; Cheng, Y-H

    2015-01-01

    Influenza poses a significant public health burden worldwide. Understanding how and to what extent people would change their behaviour in response to influenza outbreaks is critical for formulating public health policies. We incorporated the information-theoretic framework into a behaviour-influenza (BI) transmission dynamics system in order to understand the effects of individual behavioural change on influenza epidemics. We showed that information transmission of risk perception played a crucial role in the spread of health-seeking behaviour throughout influenza epidemics. Here a network BI model provides a new approach for understanding the risk perception spread and human behavioural change during disease outbreaks. Our study allows simultaneous consideration of epidemiological, psychological, and social factors as predictors of individual perception rates in behaviour-disease transmission systems. We suggest that a monitoring system with precise information on risk perception should be constructed to effectively promote health behaviours in preparation for emerging disease outbreaks.

  2. Behaviour Control Features in People of Different Professions

    Directory of Open Access Journals (Sweden)

    N S Terekhina

    2014-12-01

    Full Text Available The article presents the results of the research of the psychological characteristics, including the behavior regulation, of people of different professions: with their activity strictly regulated (pilots, N = 44 and with flexible timetables (freelancers, teachers... N = 40. It is shown that there exist certain development features of the behavior control components (volitional, cognitive control and emotional regulation and the relationship between these components in groups of people with a different degree of professional activity regulation. The behaviour control of pilots is characterized by a higher integration and interrelation of all the components, whereas the behavior control of people working flexible hours has lower connectivity and fragmentation of its components.

  3. Dynamics and Control of a Maglev Vehicle

    Directory of Open Access Journals (Sweden)

    Won ko

    2006-06-01

    Full Text Available In this paper, dynamics of a Maglev vehicle was analyzed and controls utilizing an optimized damping and an LQR algorithms were designed to stabilize the vehicle. The dynamics of magnetically levitated and propelled Maglev vehicle are complex and inherently unstable. Moreover, 6-DOF system dynamics is highly nonlinear and coupled. The proposed control schemes provide the dynamic stability and controllability, which computer simulations confirmed the effectiveness.

  4. Measurement and analysis on dynamic behaviour of parallel-plate assembly in nuclear reactors

    International Nuclear Information System (INIS)

    Chen Junjie; Guo Changqing; Zou Changchuan

    1997-01-01

    Measurement and analysis on dynamic behaviour of parallel-plate assembly in nuclear reactors have been explored. The electromagnetic method, a new method of measuring and analysing dynamic behaviour with the parallel-plate assembly as the structure of multi-parallel-beams joining with single-beam, has been presented. Theoretical analysis and computation results of dry-modal natural frequencies show good agreement with experimental measurements

  5. Dynamic shifting in thalamocortical processing during different behavioural states.

    OpenAIRE

    Nicolelis, Miguel A L; Fanselow, Erika E

    2002-01-01

    Recent experiments in our laboratory have indicated that as rats shift the behavioural strategy employed to explore their surrounding environment, there is a parallel change in the physiological properties of the neuronal ensembles that define the main thalamocortical loop of the trigeminal somatosensory system. Based on experimental evidence from several laboratories, we propose that this concurrent shift in behavioural strategy and thalamocortical physiological properties provides rats with...

  6. Modification to 200 MW(e) CANDU for improved dynamic behaviour

    International Nuclear Information System (INIS)

    Chamany, B.F.; Murthy, L.G.K.; Ray, R.N.

    1976-01-01

    Rajasthan Atomic Power Station is inherently suitable for base load operation. Its control philosophy is based on turbine following the reactor. However, due to load fluctuations and inherent limitation of the control system, there had been considerable number of outages of the station. This limitation is further enhanced by improper choice of the operating pressure range of the boilers. Besides, existing fuel design does not permit thermal cycling and hence there is no use in attempting to make the reactor follow the turbine. Design modifications have been suggested for incorporation in the further 200 MW(e) systems. The method adopted is complete decoupling of the reactor from the load. Dynamic behaviour of the station with the suggested modifications and its comparison with the existing situation has been brought out. (author)

  7. Coherent control of plasma dynamics

    Science.gov (United States)

    He, Zhaohan

    2014-10-01

    The concept of coherent control - precise measurement or determination of a process through control of the phase of an applied oscillating field - has been applied to numerous systems with great success. Here, we demonstrate the use of coherent control on plasma dynamics in a laser wakefield electron acceleration experiment. A tightly focused femtosecond laser pulse (10 mJ, 35 fs) was used to generate electron beams by plasma wakefield acceleration in the density down ramp. The technique is based on optimization of the electron beam using a deformable mirror adaptive optical system with an iterative evolutionary genetic algorithm. The image of the electrons on a scintillator screen was processed and used in a fitness function as direct feedback for the optimization algorithm. This coherent manipulation of the laser wavefront leads to orders of magnitude improvement to the electron beam properties such as the peak charge and beam divergence. The laser beam optimized to generate the best electron beam was not the one with the ``best'' focal spot. When a particular wavefront of laser light interacts with plasma, it can affect the plasma wave structures and trapping conditions of the electrons in a complex way. For example, Raman forward scattering, envelope self-modulation, relativistic self-focusing, and relativistic self-phase modulation and many other nonlinear interactions modify both the pulse envelope and phase as the pulse propagates, in a way that cannot be easily predicted and that subsequently dictates the formation of plasma waves. The optimal wavefront could be successfully determined via the heuristic search under laser-plasma conditions that were not known a priori. Control and shaping of the electron energy distribution was found to be less effective, but was still possible. Particle-in-cell simulations were performed to show that the mode structure of the laser beam can affect the plasma wave structure and trapping conditions of electrons, which

  8. Development of visual motion perception for prospective control: Brain and behavioural studies in infants

    Directory of Open Access Journals (Sweden)

    Seth B. Agyei

    2016-02-01

    Full Text Available During infancy, smart perceptual mechanisms develop allowing infants to judge time-space motion dynamics more efficiently with age and locomotor experience. This emerging capacity may be vital to enable preparedness for upcoming events and to be able to navigate in a changing environment. Little is known about brain changes that support the development of prospective control and about processes, such as preterm birth, that may compromise it. As a function of perception of visual motion, this paper will describe behavioural and brain studies with young infants investigating the development of visual perception for prospective control. By means of the three visual motion paradigms of occlusion, looming, and optic flow, our research shows the importance of including behavioural data when studying the neural correlates of prospective control.

  9. Material operating behaviour of ABB BWR control rods

    International Nuclear Information System (INIS)

    Rebensdorff, B.; Bart, G.

    2000-01-01

    The BWR control rods made by ABB use boron carbide (B 4 C and hafnium as absorber material within a cladding of stainless steel. The general behaviour under operation has proven to be very good. ABB and many of their control rod customers have performed extensive inspection programs of control rod behaviour. However, due to changes in the material properties under fast and thermal neutron irradiation defects may occur in the control rods at high neutron fluences. Examinations of irradiated control rod materials have been performed in hot cell laboratories. The examinations have revealed the defect mechanism Irradiation Assisted Stress Corrosion Cracking (IASCC) to appear in the stainless steel cladding. For IASCC to occur three factors have to act simultaneously. Stress, material sensitization and an oxidising environment. Stress may be obtained from boron carbide swelling due to irradiation. Stainless steel may be sensitized to intergranular stress corrosion cracking under irradiation. Normally the reactor environment in a BWR is oxidising. The presentation focuses on findings from hot cell laboratory work on irradiated ABB BWR control rods and studies of irradiated control rod materials in the hot cells at PSI. Apart from physical, mechanical and microstructural examinations, isotope analyses were performed to describe the local isotopic burnup of boron. Consequences (such as possible B 4 C washout) of a under operation in a ABB BWR, after the occurrence of a crack is discussed based on neutron radiographic examinations of control rods operated with cracks. (author)

  10. Neural correlates of dynamically evolving interpersonal ties predict prosocial behaviour

    Directory of Open Access Journals (Sweden)

    Johannes Jacobus Fahrenfort

    2012-03-01

    Full Text Available There is a growing interest for the determinants of human choice behaviour in social settings. Upon initial contact, investment choices in social settings can be inherently risky, as the degree to which the other person will reciprocate is unknown. Nevertheless, people have been shown to exhibit prosocial behaviour even in one-shot laboratory settings where all interaction has been taken away. A logical step has been to link such behaviour to trait empathy-related neurobiological networks. However, as a social interaction unfolds, the degree of uncertainty with respect to the expected payoff of choice behaviour may change as a function of the interaction. Here we attempt to capture this factor. We show that the interpersonal tie one develops with another person during interaction - rather than trait empathy - motivates investment in a public good that is shared with an anonymous interaction partner. We examined how individual differences in trait empathy and interpersonal ties modulate neural responses to imposed monetary sharing. After, but not before interaction in a public good game, sharing prompted activation of neural systems associated with reward (striatum, empathy (anterior insular cortex [AIC] and anterior cingulate cortex [ACC] as well as altruism and social significance (posterior superior temporal sulcus [pSTS]. Although these activations could be linked to both empathy and interpersonal ties, only tie-related pSTS activation predicted prosocial behaviour during subsequent interaction, suggesting a neural substrate for keeping track of social relevance.

  11. The dynamics of consumer behaviour. On habit, discontent, and other fish to fry.

    Science.gov (United States)

    Scholderer, Joachim; Trondsen, Torbjørn

    2008-11-01

    Recent research has drawn attention to the role of past behaviour and habit in the overall structure of consumer behaviour. We argue that in cross-sectional data past behaviour and habit must be confounded with present beliefs and attitudes when the behaviour in question has been enacted numerous times before. To disentangle the effects, longitudinal data were collected from a large panel of Norwegian consumers (effective N=4184) in 1996, 2000, and 2004. Cross-lagged panel analysis indicated that higher consumption of traditional seafood led to increasingly negative evaluations of the product supply. These negative evaluations, in turn, prompted substitution of traditional seafood with newly available, processed seafood products and an increasing dominance of aqua-cultured species. The theoretical discussion focuses on the inability of static models of consumer behaviour (in particular, the theory of planned behaviour) to capture such dynamic effects. Marketing and policy implications related to the changing structure of the seafood market are outlined.

  12. Dynamical behaviour of neuronal networks iterated with memory

    International Nuclear Information System (INIS)

    Melatagia, P.M.; Ndoundam, R.; Tchuente, M.

    2005-11-01

    We study memory iteration where the updating consider a longer history of each site and the set of interaction matrices is palindromic. We analyze two different ways of updating the networks: parallel iteration with memory and sequential iteration with memory that we introduce in this paper. For parallel iteration, we define Lyapunov functional which permits us to characterize the periods behaviour and explicitly bounds the transient lengths of neural networks iterated with memory. For sequential iteration, we use an algebraic invariant to characterize the periods behaviour of the studied model of neural computation. (author)

  13. A dynamic model of the greenhouse effect and its control

    International Nuclear Information System (INIS)

    Perman, R.; Nisbet, R.; Ma, Y.

    1991-01-01

    A dynamic model is developed for the analysis of programmes to control the greenhouse effect. The model uses simplified representations of physical processes determining climate change, linked to an economic model of emissions and emissions abatement. Feedbacks between physical and economic processes are incorporated, and the costs of emissions reduction are compared with the benefits through averted damage. Simulation analyses explore the relative merits of several intervention scenarios, each of which is compared with non intervention. Throughout the paper, emphasis is placed upon the long term consequences of behaviour, and the patterns of dynamic adjustment over time. (author)

  14. Ecological Dynamics as a Theoretical Framework for Development of Sustainable Behaviours towards the Environment

    Science.gov (United States)

    Brymer, Eric; Davids, Keith

    2013-01-01

    This paper proposes how the theoretical framework of ecological dynamics can provide an influential model of the learner and the learning process to pre-empt effective behaviour changes. Here we argue that ecological dynamics supports a well-established model of the learner ideally suited to the environmental education context because of its…

  15. Dynamic behaviour of AA 2024 under blast loading : experiments and simulations

    NARCIS (Netherlands)

    Mediavilla Varas, J.; Soetens, F.; van der Meulen, Ronald; Kroon, E.; Aanhold, van J.E.; Soetens, F.; Katgerman, L.

    2010-01-01

    The dynamic behaviour of AA2024-T3 is investigated. Dynamic tensile tests using a servo-hydraulic and a light weight shock testing machine (LSM) have been performed. The servo-hydraulic test machine proves to be more reliable and reaches higher strain rates. Neither test revealed any strain rate

  16. Pharmacological/dynamic rehabilitative behavioural therapy for premature ejaculation: Results of a pilot study

    Directory of Open Access Journals (Sweden)

    Franco Mantovani

    2017-06-01

    Full Text Available Objectives: Premature ejaculation (PE is a sexual disorder characterised by excessive rapidity of orgasm. It is defined as either primary (60%, present since the onset of sexual activity, or secondary (40%, manifesting later in life. To date, dapoxetine is the only preparation approved for the on-demand treatment of PE. However, side effects, costs associated with the treatment of chronic PE, drug dependence and its variable effectiveness leads to a not insignificant drop-out rate. Dynamic rehabilitative/behavioural therapy may be a viable therapeutic option, working alongside pharmacological treatment, as long as the participation and involvement of both the individual and the couple is optimal. Materials and methods: 18 patients were enrolled, aged between 25 and 55 (mean: 40, all with primary PE, free of comorbidities and with their partners involved. Six patients were prescribed 30 mg dapoxetine two hours before sexual relations for 3 months (group A; 6 patients began the dynamic rehabilitative treatment (group B; 6 other couples were assigned to pharmacological treatment in association with dynamic rehabilitative behavioural treatment for 3 months (group C. Division of subjects was carried out by simple randomisation, excluding patients with a short frenulum, phimosis, ED, chronic prostatitis or experiencing results from previous treatment. Results: Outcomes of treatment were evaluated at the end of the 3 months of treatment and 3 months after discontinuing treatment. In Group A 75% of patients were cured at 3 months and 25% at 6 months. In Group B 25% patients were cured at 3 months and 25% at 6 months. In Group C 75% of patients were cured 3 months and 50% at 6 months. "Cured" means a Premature Ejaculation Diagnostic Tool (PEDT score reduced from an average of 12 to an average of 6 and Intravaginal Ejaculation Latency Time (IELT values from < 1 to > 6 minutes. Conclusions: the integration of pharmacological treatment with dynamic

  17. Static and dynamic wetting behaviour of ionic liquids.

    Science.gov (United States)

    Delcheva, Iliana; Ralston, John; Beattie, David A; Krasowska, Marta

    2015-08-01

    Ionic liquids (ILs) are a unique family of molecular liquids ('molten salts') that consist of a combination of bulky organic cations coupled to inorganic or organic anions. The net result of steric hindrance and strong hydrogen bonding between components results in a material that is liquid at room temperature. One can alter the properties of ionic liquids through chemical modification of anion and cation, thus tailoring the IL for a given application. One such property that can be controlled or selected is the wettability of an IL on a particular solid substrate. However, the study of wetting of ionic liquids is complicated by the care required for accurate and reproducible measurement, due to both the susceptibility of the IL properties to water content, as well as to the sensitivity of wettability measurements to the state of the solid surface. This review deals with wetting studies of ILs to date, including both static and dynamic wetting, as well as issues concerning line tension and the formation of precursor and wetting films. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Spatial vision in insects is facilitated by shaping the dynamics of visual input through behavioural action

    Directory of Open Access Journals (Sweden)

    Martin eEgelhaaf

    2012-12-01

    Full Text Available Insects such as flies or bees, with their miniature brains, are able to control highly aerobatic flight manoeuvres and to solve spatial vision tasks, such as avoiding collisions with obstacles, landing on objects or even localizing a previously learnt inconspicuous goal on the basis of environmental cues. With regard to solving such spatial tasks, these insects still outperform man-made autonomous flying systems. To accomplish their extraordinary performance, flies and bees have been shown by their characteristic behavioural actions to actively shape the dynamics of the image flow on their eyes (optic flow. The neural processing of information about the spatial layout of the environment is greatly facilitated by segregating the rotational from the translational optic flow component through a saccadic flight and gaze strategy. This active vision strategy thus enables the nervous system to solve apparently complex spatial vision tasks in a particularly efficient and parsimonious way. The key idea of this review is that biological agents, such as flies or bees, acquire at least part of their strength as autonomous systems through active interactions with their environment and not by simply processing passively gained information about the world. These agent-environment interactions lead to adaptive behaviour in surroundings of a wide range of complexity. Animals with even tiny brains, such as insects, are capable of performing extraordinarily well in their behavioural contexts by making optimal use of the closed action–perception loop. Model simulations and robotic implementations show that the smart biological mechanisms of motion computation and visually-guided flight control might be helpful to find technical solutions, for example, when designing micro air vehicles carrying a miniaturized, low-weight on-board processor.

  19. Multibody system dynamics, robotics and control

    CERN Document Server

    Gerstmayr, Johannes

    2013-01-01

    The volume contains 19 contributions by international experts in the field of multibody system dynamics, robotics and control. The book aims to bridge the gap between the modeling of mechanical systems by means of multibody dynamics formulations and robotics. In the classical approach, a multibody dynamics model contains a very high level of detail, however, the application of such models to robotics or control is usually limited. The papers aim to connect the different scientific communities in multibody dynamics, robotics and control. Main topics are flexible multibody systems, humanoid robots, elastic robots, nonlinear control, optimal path planning, and identification.

  20. Dynamic market behaviour of autonomous network based power systems

    NARCIS (Netherlands)

    Jokic, A.; Wittebol, E.H.M.; Bosch, van den P.P.J.

    2006-01-01

    Dynamic models of real-time markets are important since they lead to additional insights of the behavior and stability of power system markets. The main topic of this paper is the analysis of real-time market dynamics in a novel power system structure that is based on the concept of autonomous

  1. Aero dynamical and mechanical behaviour of the Savonius rotor

    Energy Technology Data Exchange (ETDEWEB)

    Aouachria, Z. [Batna Univ., (Algeria). Applied Energetic Physics Laboratory

    2009-07-01

    Although the Savonius wind turbine is not as efficient as the traditional Darrieus wind turbine, its rotor design has many advantages such as simple construction; acceptance of wind from all directions; high starting torque; operation at relatively low speed; and easy adaptation to urban sites. These advantages may outweigh its low efficiency and make it suitable for small-scale power requirements such as pumping and rural electrification. This paper presented a study of the aerodynamic behaviour of a Savonius rotor, based on blade pressure measurements. A two-dimensional analysis method was used to determine the aerodynamic strengths, which leads to the Magnus effect and the generation of the vibrations on the rotor. The study explained the vibratory behaviour of the rotor and proposed an antivibration system to protect the machine. 14 refs., 1 tab., 9 figs.

  2. Comparative behaviour of the Dynamically Penalized Likelihood algorithm in inverse radiation therapy planning

    Energy Technology Data Exchange (ETDEWEB)

    Llacer, Jorge [EC Engineering Consultants, LLC, Los Gatos, CA (United States)]. E-mail: jllacer@home.com; Solberg, Timothy D. [Department of Radiation Oncology, University of California, Los Angeles, CA (United States)]. E-mail: Solberg@radonc.ucla.edu; Promberger, Claus [BrainLAB AG, Heimstetten (Germany)]. E-mail: promberg@brainlab.com

    2001-10-01

    This paper presents a description of tests carried out to compare the behaviour of five algorithms in inverse radiation therapy planning: (1) The Dynamically Penalized Likelihood (DPL), an algorithm based on statistical estimation theory; (2) an accelerated version of the same algorithm; (3) a new fast adaptive simulated annealing (ASA) algorithm; (4) a conjugate gradient method; and (5) a Newton gradient method. A three-dimensional mathematical phantom and two clinical cases have been studied in detail. The phantom consisted of a U-shaped tumour with a partially enclosed 'spinal cord'. The clinical examples were a cavernous sinus meningioma and a prostate case. The algorithms have been tested in carefully selected and controlled conditions so as to ensure fairness in the assessment of results. It has been found that all five methods can yield relatively similar optimizations, except when a very demanding optimization is carried out. For the easier cases, the differences are principally in robustness, ease of use and optimization speed. In the more demanding case, there are significant differences in the resulting dose distributions. The accelerated DPL emerges as possibly the algorithm of choice for clinical practice. An appendix describes the differences in behaviour between the new ASA method and the one based on a patent by the Nomos Corporation. (author)

  3. Dynamic optimization and adaptive controller design

    Science.gov (United States)

    Inamdar, S. R.

    2010-10-01

    In this work I present a new type of controller which is an adaptive tracking controller which employs dynamic optimization for optimizing current value of controller action for the temperature control of nonisothermal continuously stirred tank reactor (CSTR). We begin with a two-state model of nonisothermal CSTR which are mass and heat balance equations and then add cooling system dynamics to eliminate input multiplicity. The initial design value is obtained using local stability of steady states where approach temperature for cooling action is specified as a steady state and a design specification. Later we make a correction in the dynamics where material balance is manipulated to use feed concentration as a system parameter as an adaptive control measure in order to avoid actuator saturation for the main control loop. The analysis leading to design of dynamic optimization based parameter adaptive controller is presented. The important component of this mathematical framework is reference trajectory generation to form an adaptive control measure.

  4. Dynamic behaviour of a typical PHWR under earthquake load conditions

    International Nuclear Information System (INIS)

    Fischer, U.; Brandt, K.; Krutzik, N.J.

    1984-01-01

    The paper deals with dynamic calculations for a PHWR reactor building founded on rock and on a base isolation system. The zero period accelerations, displacements, mode shapes and the floor response spectra of both calculations are compared. (Author) [pt

  5. Behaviour of steel arch supports under dynamic effects of rockbursts

    Czech Academy of Sciences Publication Activity Database

    Horyl, P.; Šňupárek, Richard

    2007-01-01

    Roč. 116, č. 3 (2007), s. 119-128 ISSN 0371-7844 Institutional research plan: CEZ:AV0Z30860518 Keywords : steel arch support * rockbursts * dynamic loading Subject RIV: DH - Mining , incl. Coal Mining

  6. Thermal behaviour in dynamic recrystallisation. Application for iron base alloys

    International Nuclear Information System (INIS)

    Belkebir, A.; Kobylanski, A.

    1995-01-01

    A constitutive relationship for predicting the flow stress with dynamic recrystallization were proposed. The approach is based on a phenomenological formalism of the law θ-ε where θ correspond to the work-hardening rate at constant strain rate and temperature. The equations proposed were justified by the experimental data collected by hot compression test of low-alloy steels. The model can be used to estimate the critical strain for the onset of dynamic recrystallization. (orig.)

  7. Strong field control of predissociation dynamics.

    Science.gov (United States)

    Corrales, María E; Balerdi, Garikoitz; Loriot, Vincent; de Nalda, Rebeca; Bañares, Luis

    2013-01-01

    Strong field control scenarios are investigated in the CH3I predissociation dynamics at the origin of the second absorption B-band, in which state-selective electronic predissociation occurs through the crossing with a valence dissociative state. Dynamic Stark control (DSC) and pump-dump strategies are shown capable of altering both the predissociation lifetime and the product branching ratio.

  8. Pervasive developmental disorders and criminal behaviour - A case control study

    DEFF Research Database (Denmark)

    Mouridsen, S.E.; Rich, B.; Isager, T.

    2008-01-01

    The prevalence and pattern of criminal behaviour in a population of 313 former child psychiatric in-patients with pervasive developmental disorders were studied. The patients were divided into three subgroups and compared with 933 matched controls from the general population. Age at follow.......1% and 18.4%, respectively. The corresponding rate of convictions in the comparison groups was 18.9%, 14.7%, and 19.6% respectively. Particular attention is given to arson in Asperger's syndrome (P = .0009) Udgivelsesdato: 2008/4...

  9. Chaotic behaviour and controlling chaos in free electron lasers

    International Nuclear Information System (INIS)

    Wang Wenjie; Chen Shigang; Du Xiangwan; Wang Guangrui

    1995-01-01

    Chaos in free electron lasers (FEL) is reviewed. Special attention has been paid to the chaotic behaviour of the electrons and the laser field. The problem of controlling and utilizing chaotic motion of the electrons and the laser field has also been discussed. In order to find out the rules of instability and chaos in FEL, some typical methods of the chaotic theory are used. These methods include making the Poincare surface of section, drawing the phase space diagrams of the electron orbits, calculating the Liapunov exponents, and computing the power spectrum, etc. Finally, some problems in FEL research are discussed (103 refs., 54 figs.)

  10. Einstein-Friedmann equation, nonlinear dynamics and chaotic behaviours

    International Nuclear Information System (INIS)

    Tanaka, Yosuke; Nakano, Shingo; Ohta, Shigetoshi; Mori, Keisuke; Horiuchi, Tanji

    2009-01-01

    We have studied the Einstein-Friedmann equation [Case 1] on the basis of the bifurcation theory and shown that the chaotic behaviours in the Einstein-Friedmann equation [Case 1] are reduced to the pitchfork bifurcation and the homoclinic bifurcation. We have obtained the following results: (i) 'The chaos region diagram' (the p-λ plane) in the Einstein-Friedmann equation [Case 1]. (ii) 'The chaos inducing chart' of the homoclinic orbital systems in the unforced differential equations. We have discussed the non-integrable conditions in the Einstein-Friedmann equation and proposed the chaotic model: p=p 0 ρ n (n≥0). In case n≠0,1, the Einstein-Friedmann equation is not integrable and there may occur chaotic behaviours. The cosmological constant (λ) turns out to play important roles for the non-integrable condition in the Einstein-Friedmann equation and also for the pitchfork bifurcation and the homoclinic bifurcation in the relativistic field equation. With the use of the E-infinity theory, we have also discussed the physical quantities in the gravitational field equations, and obtained the formula logκ=-10(1/φ) 2 [1+(φ) 8 ]=-26.737, which is in nice agreement with the experiment (-26.730).

  11. The dynamics of aerosol behaviour and fate within spruce canopies

    International Nuclear Information System (INIS)

    Ould-Dada, Zitouni

    1996-01-01

    The current work was intended to provide data on aerosol inputs to forest ecosystems and their subsequent fate. The background to the project was the Chernobyl accident which highlighted the importance of forests and other semi-natural ecosystems as a link in the transfer of radioactivity to man. In the aftermath of the Chernobyl accident, forests were identified as a specific type of semi-natural ecosystem for which radioecological data were almost completely absent within the countries of the European Union. Information on radionuclide behaviour and transfer in forest ecosystems was therefore needed to establish and test radiological assessment models which can be used to evaluate the likely contribution to radiological dose-to-man contaminated forests may make. The objective of this study was thus to provide data on dry deposition, resuspension and field loss of aerosols to forest canopies, in particular those of Norway spruce (Picea abies), from wind tunnel experiments conducted with small scale 'model' canopies. An aerosol generation system was developed to produce aerosol particles in the size range of 0.13-1.37 μm (VMD). Particle size distributions can be controlled within desired limits and with sufficient stability over time allowing the technique to be suitable for use in extended aerosol deposition studies. A full scale dry deposition experiment using 0.82 μm (VMAD) uranium particles was performed in the wind tunnel using Norway spruce saplings of approximately 45 cm height. Deposition velocities (V g ) were obtained and these were related to meteorological measurements (wind speed, friction velocity, turbulence intensity) inside the wind tunnel and LAI of the canopy. The latter was divided into five horizontal layers and both horizontal and vertical variations in deposition were assessed. A V g value of 0.497 cm s -1 was obtained for the canopy as a whole with the highest and lowest fluxes of 2.85 x 10 -8 and 8.14 x 10 -9 μgU cm -2 s -1 occurring at

  12. Theory of planned behaviour variables and objective walking behaviour do not show seasonal variation in a randomised controlled trial.

    Science.gov (United States)

    Williams, Stefanie L; French, David P

    2014-02-05

    Longitudinal studies have shown that objectively measured walking behaviour is subject to seasonal variation, with people walking more in summer compared to winter. Seasonality therefore may have the potential to bias the results of randomised controlled trials if there are not adequate statistical or design controls. Despite this there are no studies that assess the impact of seasonality on walking behaviour in a randomised controlled trial, to quantify the extent of such bias. Further there have been no studies assessing how season impacts on the psychological predictors of walking behaviour to date. The aim of the present study was to assess seasonal differences in a) objective walking behaviour and b) Theory of Planned Behaviour (TPB) variables during a randomised controlled trial of an intervention to promote walking. 315 patients were recruited to a two-arm cluster randomised controlled trial of an intervention to promote walking in primary care. A series of repeated measures ANCOVAs were conducted to examine the effect of season on pedometer measures of walking behaviour and TPB measures, assessed immediately post-intervention and six months later. Hierarchical regression analyses were conducted to assess whether season moderated the prediction of intention and behaviour by TPB measures. There were no significant differences in time spent walking in spring/summer compared to autumn/winter. There was no significant seasonal variation in most TPB variables, although the belief that there will be good weather was significantly higher in spring/summer (F = 19.46, p behaviour, or moderate the effects of TPB variables on intention or behaviour. Seasonality does not influence objectively measured walking behaviour or psychological variables during a randomised controlled trial. Consequently physical activity behaviour outcomes in trials will not be biased by the season in which they are measured. Previous studies may have overestimated the extent of

  13. Mechanical and dynamic mechanical behaviour of novel glass ...

    Indian Academy of Sciences (India)

    M Rajesh

    the intra-ply woven fabric hybridization enhances impact and damping properties of the composite ... Keywords. Intra-ply hybrid; natural fibre; mechanical properties; dynamic mechanical analysis; vibration; .... analysis test is conducted in nitrogen environment over a ..... Mnson J A and Jolliet O 2001 Life cycle assessment of.

  14. Relationship dynamics and sexual risk behaviour of male partners of ...

    African Journals Online (AJOL)

    A few men also admitted to being motivated by material and financial benefits from sex workers who they perceived as being rich and this was one factor that helped them sustain the relationships. These findings offer insights into the complex relationship dynamics within high risk sexual partnerships. However, the findings ...

  15. Transient behaviour and control of the ACACIA plant

    International Nuclear Information System (INIS)

    Kikstra, J.F.; Heek, A.I. van; Verkooijen, A.H.M.

    2001-01-01

    This article deals with dynamic modelling and control of the ACACIA plant. A one-dimensional flow model describing the helium flow and the two-phase water flow is used through the whole plant, with different source terms in different pieces of equipment. A stage-by-stage model is produced for the radial compressor and axial turbine. Other models include the recuperator, water/helium heat exchangers, a natural convection evaporator, valves, etc. The models have been checked by comparison of the transient behavior with several other models, e.g. produced in RELAP. The dynamic behavior of this plant is analysed and a control structure is designed. First the requirements and options for a control system design are investigated. A number of possible control valve positions in the flowsheet are tested with transients in order to make an argued choice. The model is subsequently used to determine the optimal working conditions for different heat and power demands, these are used as set-points for the control system. Then the interaction between manipulated and controlled variables is mapped and based on this information a choice for coupling them in decentralised feedback control loops is made. This control structure is then tuned and tested. It can be concluded that both heat and power demand can be followed with acceptable performance over a wide range. (author)

  16. Analysis of static and dynamic pile-soil-jacket behaviour

    Energy Technology Data Exchange (ETDEWEB)

    Azadi, Mohammad Reza Emami

    1998-12-31

    In the offshore industry, recent extreme storms, severe earthquakes and subsidence of the foundation of jacket platforms have shown that new models and methods must take into account the jacket- pile-soil foundation interaction as well as the non-linear dynamic performance/loading effects. This thesis begins with a review of the state of art pile-soil interaction model, recognizing that most existing pile-soil models have been established based on large diameter pile tests on specific sites. The need for site independent and mechanistic pile-soil interaction models led to the development of new (t-z) and (p-y) disk models. These are validated using the available database from recent large diameter pile tests in the North Sea and Gulf of Mexico. The established static disk models are applied for non-linear static analysis of the jacket-pile-soil system under extreme wave loading. Dynamic pile-soil interaction is studied and a new disk-cone model is developed for the non-linear and non-homogeneous soils. This model is applied to both surface and embedded disks in a soil layer with non-linear properties. Simplified non-linear as well as more complex analysis methods are used to study the dynamic response of the jacket platform under extreme sea and seismic loading. Ductility spectra analysis is introduced and used to study the dynamic performance of the jacket systems near collapse. Case studies are used to illustrate the effects of structural, foundation failure characteristics as well as dynamic loading effects on the overall performance of the jacket-pile-soil systems near ultimate collapse. 175 refs., 429 figs., 70 tabs.

  17. Roles for the subiculum in spatial information processing, memory, motivation and the temporal control of behaviour.

    Science.gov (United States)

    O'Mara, Shane M; Sanchez-Vives, Maria V; Brotons-Mas, Jorge R; O'Hare, Eugene

    2009-08-01

    The subiculum is in a pivotal position governing the output of the hippocampal formation. Despite this, it is a rather under-explored and sometimes ignored structure. Here, we discuss recent data indicating that the subiculum participates in a wide range of neurocognitive functions and processes. Some of the functions of subiculum are relatively well-known-these include providing a relatively coarse representation of space and participating in, and supporting certain aspects of, memory (particularly in the dynamic bridging of temporal intervals). The subiculum also participates in a wide variety of other neurocognitive functions too, however. Much less well-known are roles for the subiculum, and particularly the ventral subiculum, in the response to fear, stress and anxiety, and in the generation of motivated behaviour (particularly the behaviour that underlies drug addiction and the response to reward). There is an emerging suggestion that the subiculum participates in the temporal control of behaviour. It is notable that these latter findings have emerged from a consideration of instrumental behaviour using operant techniques; it may well be the case that the use of the watermaze or similar spatial tasks to assess subicular function (on the presumption that its functions are very similar to the hippocampus proper) has obscured rather than revealed neurocognitive functions of subiculum. The anatomy of subiculum suggests it participates in a rather subtle fashion in a very broad range of functions, rather than in a relatively more isolated fashion in a narrower range of functions, as might be the case for "earlier" components of hippocampal circuitry, such as the CA1 and CA3 subfields. Overall, there appears to a strong dorso-ventral segregation of function within subiculum, with the dorsal subiculum relatively more concerned with space and memory, and the ventral hippocampus concerned with stress, anxiety and reward. Finally, it may be the case that the whole

  18. Occupant Behaviour with regard to Control of the Indoor Environment

    DEFF Research Database (Denmark)

    Andersen, Rune Vinther

    A large proportion of the world’s energy consumption is spent in an effort to maintain a comfortable and healthy indoor environment. As a consequence reductions in the energy consumed to climatise buildings are instrumental to the efforts of reducing energy related CO2 emissions and alleviating....... As a consequence, most programs are capable of accurate simulations of the physical properties of a building. However, even though the occupants’ control of the various systems in the building has a significant impact on the energy consumption and the indoor environment, only few studies have focused...... on the behaviour of their occupants. As a consequence, there is a need to investigate occupants’ interactions with building controls, such as opening of windows, adjustments of heating set-points, use of solar shading, etc. Some models of occupants’ interactions with operable windows do exist, but these are based...

  19. Malaria control in rural Malawi: implementing peer health education for behaviour change.

    Science.gov (United States)

    Malenga, Tumaini; Kabaghe, Alinune Nathanael; Manda-Taylor, Lucinda; Kadama, Asante; McCann, Robert S; Phiri, Kamija Samuel; van Vugt, Michèle; van den Berg, Henk

    2017-11-20

    Interventions to reduce malaria burden are effective if communities use them appropriately and consistently. Several tools have been suggested to promote uptake and use of malaria control interventions. Community workshops on malaria, using the 'Health Animator' approach, are a potential behaviour change strategy for malaria control. The strategy aims to influence a change in mind-set of vulnerable populations to encourage self-reliance, using community volunteers known as Health Animators. The aim of the paper is to describe the process of implementing community workshops on malaria by Health Animators to improve uptake and use of malaria control interventions in rural Malawi. This is a descriptive study reporting feasibility, acceptability, appropriateness and fidelity of using Health Animator-led community workshops for malaria control. Quantitative data were collected from self-reporting and researcher evaluation forms. Qualitative assessments were done with Health Animators, using three focus groups (October-December 2015) and seven in-depth interviews (October 2016-February 2017). Seventy seven health Animators were trained from 62 villages. A total of 2704 workshops were conducted, with consistent attendance from January 2015 to June 2017, representing 10-17% of the population. Attendance was affected by social responsibilities and activities, relationship of the village leaders and their community and involvement of Community Health Workers. Active discussion and participation were reported as main strengths of the workshops. Health Animators personally benefited from the mind-set change and were proactive peer influencers in the community. Although the information was comprehended and accepted, availability of adequate health services was a challenge for maintenance of behaviour change. Community workshops on malaria are a potential tool for influencing a positive change in behaviour towards malaria, and applicable for other health problems in rural

  20. Symmetric dynamic behaviour of a superconducting proximity array with respect to field reversal

    International Nuclear Information System (INIS)

    Lankhorst, M; Poccia, N

    2017-01-01

    As the complexity of strongly correlated systems and high temperature superconductors increases, so does also the essential complexity of defects found in these materials and the complexity of the supercurrent pathways. It can be therefore convenient to realize a solid-state system with regular supercurrent pathways and without the disguising effects of disorder in order to capture the essential characteristics of a collective dynamics. Using a square array of superconducting islands placed on a normal metal, we observe a state in which magnetic field-induced vortices are frozen in the dimples of the egg crate potential by their strong repulsion interaction. In this system a dynamic vortex Mott insulator transition has been previously observed. In this work, we will show the symmetric dynamic behaviour with respect to field reversal and we will compare it with the asymmetric behaviour observed at the dynamic vortex Mott transition. (paper)

  1. Dynamic control of traffic lights

    NARCIS (Netherlands)

    Haijema, Rene; Hendrix, Eligius M.T.; Wal, van der Jan

    2017-01-01

    Traffic lights are put in place to dynamically change priority between traffic participants. Commonly, the duration of green intervals and the grouping, and ordering in which traffic flows are served are pre-fixed. In this chapter, the problem of minimizing vehicle delay at isolated intersections is

  2. Behaviour of soil-cement specimens in unconfined dynamic compression

    Science.gov (United States)

    Davies, J.; Fendukly, L. M.

    1994-06-01

    The response of the cement-stabilized red marl to dynamic loading in compression has been investigated over a range of cement contents and curing times. Specimens were subjected to different stress levels below unconfined compressive strength, at a frequency of 5 Hz, and a fatigue relationship for the material was developed. The value of resilient modulus was found to be greater than the modulus of elasticity for the same cement content and curing time.

  3. The Dynamics of Addiction: Craving versus Self-Control.

    Directory of Open Access Journals (Sweden)

    Johan Grasman

    Full Text Available This study deals with addictive acts that exhibit a stable pattern not intervening with the normal routine of daily life. Nevertheless, in the long term such behaviour may result in health damage. Alcohol consumption is an example of such addictive habit. The aim is to describe the process of addiction as a dynamical system in the way this is done in the natural and technological sciences. The dynamics of the addictive behaviour is described by a mathematical model consisting of two coupled difference equations. They determine the change in time of two state variables, craving and self-control. The model equations contain terms that represent external forces such as societal rules, peer influences and cues. The latter are formulated as events that are Poisson distributed in time. With the model it is shown how a person can get addicted when changing lifestyle. Although craving is the dominant variable in the process of addiction, the moment of getting dependent is clearly marked by a switch in a variable that fits the definition of addiction vulnerability in the literature. Furthermore, the way chance affects a therapeutic addiction intervention is analysed by carrying out a Monte Carlo simulation. Essential in the dynamical model is a nonlinear component which determines the configuration of the two stable states of the system: being dependent or not dependent. Under identical external conditions both may be stable (hysteresis. With the dynamical systems approach possible switches between the two states are explored (repeated relapses.

  4. Dynamics and control of technical systems

    CERN Document Server

    Balthazar, José M; Kaczmarczyk, Stefan

    2014-01-01

    The main topics of this Special Issue are linear and, mainly, nonlinear dynamics, chaos and control of systems and structures and their applications in different field of science and engineering. According to the goal of the Special Issue, the selected contributions are divided into three major parts: ""Vibration Problems in Vertical Transportation Systems"", ""Nonlinear Dynamics, Chaos and Control of Elastic Structures"" and ""New Strategies and Challenges for Aerospace and Ocean Structures Dynamics and Control"". The discussion of real problems in aerospace and how these problems can be unde

  5. The effect of external dynamic loads on the lifetime of rolling element bearings: accurate measurement of the bearing behaviour

    International Nuclear Information System (INIS)

    Jacobs, W; Boonen, R; Sas, P; Moens, D

    2012-01-01

    Accurate prediction of the lifetime of rolling element bearings is a crucial step towards a reliable design of many rotating machines. Recent research emphasizes an important influence of external dynamic loads on the lifetime of bearings. However, most lifetime calculations of bearings are based on the classical ISO 281 standard, neglecting this influence. For bearings subjected to highly varying loads, this leads to inaccurate estimations of the lifetime, and therefore excessive safety factors during the design and unexpected failures during operation. This paper presents a novel test rig, developed to analyse the behaviour of rolling element bearings subjected to highly varying loads. Since bearings are very precise machine components, their motion can only be measured in an accurately controlled environment. Otherwise, noise from other components and external influences such as temperature variations will dominate the measurements. The test rig is optimised to perform accurate measurements of the bearing behaviour. Also, the test bearing is fitted in a modular structure, which guarantees precise mounting and allows testing different types and sizes of bearings. Finally, a fully controlled multi-axial static and dynamic load is imposed on the bearing, while its behaviour is monitored with capacitive proximity probes.

  6. Dynamic behaviour of pump-turbine runner: From disk to prototype runner

    International Nuclear Information System (INIS)

    Huang, X X; Egusquiza, E; Valero, C; Presas, A

    2013-01-01

    In recent decades, in order to increase output power of hydroelectric turbomachinery, the design head and the flow rate of the hydraulic turbines have been increased greatly. This has led to serious vibratory problems. The pump-turbines have to work at various operation conditions to satisfy the requirements of the power grid. However, larger hydraulic forces will result in high vibration levels on the turbines, especially, when the machines operate at off-design conditions. Due to the economic considerations, the pump-turbines are built as light as possible, which will change the dynamic response of the structures. According to industrial cases, the fatigue damage of the pump-turbine runner induced by hydraulic dynamic forces usually happens on the outer edge of the crown, which is near the leading edges of blades. To better understand the reasons for this kind of fatigue, it is extremely important to investigate the dynamic response behaviour of the hydraulic turbine, especially the runner, by experimental measurement and numerical simulation. The pump-turbine runner has a similar dynamic response behaviour of the circular disk. Therefore, in this paper the dynamic response analyses for circular disks with different dimensions and disk-blades-disk structures were carried out to better understand the fundamental dynamic behaviour for the complex turbomachinery. The influences of the pattern and number of blades were discussed in detail

  7. Robust control synthesis for uncertain dynamical systems

    Science.gov (United States)

    Byun, Kuk-Whan; Wie, Bong; Sunkel, John

    1989-01-01

    This paper presents robust control synthesis techniques for uncertain dynamical systems subject to structured parameter perturbation. Both QFT (quantitative feedback theory) and H-infinity control synthesis techniques are investigated. Although most H-infinity-related control techniques are not concerned with the structured parameter perturbation, a new way of incorporating the parameter uncertainty in the robust H-infinity control design is presented. A generic model of uncertain dynamical systems is used to illustrate the design methodologies investigated in this paper. It is shown that, for a certain noncolocated structural control problem, use of both techniques results in nonminimum phase compensation.

  8. Controllable Subspaces of Open Quantum Dynamical Systems

    International Nuclear Information System (INIS)

    Zhang Ming; Gong Erling; Xie Hongwei; Hu Dewen; Dai Hongyi

    2008-01-01

    This paper discusses the concept of controllable subspace for open quantum dynamical systems. It is constructively demonstrated that combining structural features of decoherence-free subspaces with the ability to perform open-loop coherent control on open quantum systems will allow decoherence-free subspaces to be controllable. This is in contrast to the observation that open quantum dynamical systems are not open-loop controllable. To a certain extent, this paper gives an alternative control theoretical interpretation on why decoherence-free subspaces can be useful for quantum computation.

  9. Dynamic Control Based Photovoltaic Illuminating System

    Directory of Open Access Journals (Sweden)

    Zhang Chengkai

    2016-01-01

    Full Text Available Smart LED illumination system can use the power from whether the photovoltaic cell or the power grid automatically based on the SOC (State Of Charge of the photovoltaic cell. This paper proposes a feedback control of the photovoltaic cells and a dynamic control strategy for the Energy system. The dynamic control strategy is used to determine the switching state of the photovoltaic cell based on the illumination load in the past one hour and the battery capacity. These controls are manifested by experimental prototype that the control scheme is correct and effective.

  10. Catalytic properties and dynamic behaviour of uranium complexes

    International Nuclear Information System (INIS)

    Le Marechal, J.F.

    1986-01-01

    The catalytic properties of organometallic uranium III and IV compounds in solution as well as reaction mechanisms are studied. The structure in solution of CpUCl 3 L 2 (L=THF, HMPA, OPPh 3 , OP(OR) 3 ) is investigated. When L=HMPA, the complex exists in two isomers in equilibrium with the L ligands either in trans or mer-cis configuration. The isomerization (Ea=92 kJ mol -1 ) as well as the bimolecular exchange with an outer sphere ligand L are observable in 1 H and 31 P NMR, and quantified with the spin saturation transfer technique in several solvents and at different temperatures between 230 and 330 K. This property is extended to other ligands. The compound U(AlH 4 ) 3 is synthetized. This compound catalyses the hydroalumination of olefins by LiAlH 4 with a very good anti-Markovnikov regioselectivity. A simple mechanism for this reaction is suggested. The reactions of the organoaluminates products with several reactants (D 2 O, I 2 , CH 2 O, Allyl-Br...) has been shown to be a powerful synthetic tool. Some specific alkenes and alkynes exhibit an interesting behaviour as dimerization or β-alkyl elimination which is easily interpreted by our mechanism [fr

  11. Dynamical behaviour of natural convection in closed loops

    International Nuclear Information System (INIS)

    Ehrhard, P.

    1988-04-01

    A one dimensional model is presented together with experiments, which describe the natural convective flow in closed loops heated at the bottom and cooled in the upper semicircle. Starting from a single loop, mechanical and thermal coupling with a second loop is discussed. The experiments and the theoretical model both concurrently demonstrate that the investigated natural convection is clearly influenced by non-linear effects. Beside the variety of stable steady flows there are extensive subcritical ranges of convective flow. In these parameter ranges subcritical instabilities of the steady state flow could occur in the presence of finite amplitude disturbances. However, the supercritical, global unstable range is characterized by chaotic histories of the variables of state. Non-symmetric heating generates an imperfect bifurcation out of the steady solution with zero velocity in the loop. This effect stabilizes the flow in the preferred direction. The flow in the opposite direction only remains stable in a small isolated interval of the heating parameter. Furthermore the calculations with the model equations demonstrate that a stable periodic behaviour of the flow is possible in a small parameter window. However, it has not been possible to verify this particular effect in the experiments conducted to date. (orig./GL) [de

  12. Dynamic Algorithm for LQGPC Predictive Control

    DEFF Research Database (Denmark)

    Hangstrup, M.; Ordys, A.W.; Grimble, M.J.

    1998-01-01

    In this paper the optimal control law is derived for a multi-variable state space Linear Quadratic Gaussian Predictive Controller (LQGPC). A dynamic performance index is utilized resulting in an optimal steady state controller. Knowledge of future reference values is incorporated into the control......In this paper the optimal control law is derived for a multi-variable state space Linear Quadratic Gaussian Predictive Controller (LQGPC). A dynamic performance index is utilized resulting in an optimal steady state controller. Knowledge of future reference values is incorporated...... into the controller design and the solution is derived using the method of Lagrange multipliers. It is shown how well-known GPC controller can be obtained as a special case of the LQGPC controller design. The important advantage of using the LQGPC framework for designing predictive, e.g. GPS is that LQGPC enables...

  13. Using behavioural activation in the treatment of depression: a control theory perspective.

    Science.gov (United States)

    McEvoy, P; Law, A; Bates, R; Hylton, K; Mansell, W

    2013-12-01

    Behavioural activation is an intervention that can be used to counteract the typical patterns of withdrawal, avoidance and inactivity that characterize depression. This paper examines the processes of change that may occur during behavioural activation from the perspective of control theory. Some of the key concepts that are associated with control theory are introduced and the process of change that may occur during behavioural activation is illustrated using two case studies. The case studies provide anecdotal evidence which supports the hypothesis that the effective implementation of behavioural activation may depend upon clients being able to retain or regain the sense of control that they value. The differences between a control-theory-based approach and more orthodox behavioural and cognitive approaches are highlighted and the implications of these differences are discussed. Flexible approaches that are informed by control theory, may offer a useful alternative to the more established behavioural and cognitive approaches towards behavioural activation. © 2012 John Wiley & Sons Ltd.

  14. Statistics of energy levels and zero temperature dynamics for deterministic spin models with glassy behaviour

    NARCIS (Netherlands)

    Degli Esposti, M.; Giardinà, C.; Graffi, S.; Isola, S.

    2001-01-01

    We consider the zero-temperature dynamics for the infinite-range, non translation invariant one-dimensional spin model introduced by Marinari, Parisi and Ritort to generate glassy behaviour out of a deterministic interaction. It is argued that there can be a large number of metastable (i.e.,

  15. Seeing with the Mind: The Relationship Between Spatial Ability and Inferring Dynamic Behaviour from Graphs

    NARCIS (Netherlands)

    Veldhuis, G.A.; Korzilius, H.P.L.M.

    2017-01-01

    Research has shown that many individuals have difficulties solving tasks that involve a principal component of dynamic systems: accumulation. They incorrectly assume that the behavioural pattern of a stock resembles that of its flows and vice versa. This has become known as correlation heuristic

  16. Seeing with the Mind: The Relationship Between Spatial Ability and Inferring Dynamic Behaviour from Graphs.

    NARCIS (Netherlands)

    Veldhuis, G.A.; Korzilius, H.

    2016-01-01

    Research has shown that many individuals have difficulties solving tasks that involve a principal component of dynamic systems: accumulation. They incorrectly assume that the behavioural pattern of a stock resembles that of its flows and vice versa. This has become known as correlation heuristic

  17. Dynamic behaviour of non-uniform Bernoulli-Euler beams subjected ...

    African Journals Online (AJOL)

    This paper investigates the dynamics behaviour of non-uniform Bernoulli-Euler beams subjected to concentrated loads ravelling at variable velocities. The solution technique is based on the Generalized Galerkin Method and the use of the generating function of the Bessel function type. The results show that, for all the ...

  18. Behavioural modelling using the MOESP algorithm, dynamic neural networks and the Bartels-Stewart algorithm

    NARCIS (Netherlands)

    Schilders, W.H.A.; Meijer, P.B.L.; Ciggaar, E.

    2008-01-01

    In this paper we discuss the use of the state-space modelling MOESP algorithm to generate precise information about the number of neurons and hidden layers in dynamic neural networks developed for the behavioural modelling of electronic circuits. The Bartels–Stewart algorithm is used to transform

  19. Analysis of the dynamic behaviour of tanks filled with a liquid

    International Nuclear Information System (INIS)

    Ousset, Y.; Marquand, D.

    1983-01-01

    The construction of nuclear power plants sets the problem of the resistance of fuel storage tank to seisms. The presence of fluid changes sensitively the dynamic behaviour of the tank, what involves to take it into account. The CETIM choosed the method of integral equations to solve the problem of the calculation of the added mass matrix [Msub(A)] [fr

  20. Nonlinear dynamics and chaotic behaviour of spin wave instabilities

    Energy Technology Data Exchange (ETDEWEB)

    Rezende, S M; Aguiar, F.M. de.

    1986-09-01

    Recent experiments revealed that spin wave instabilities driven by microwave fields, either parallel or transverse to the static magnetic field, display chaotic dynamics similar to other physical systems. A theory based on the coupled nonlinear equations of motion for two spin wave modes is presented which explains most features of the experimental observations. The model predicts subharmonic routes to chaos that depend on the parameter values. For certain parameters the system exhibits a Feigenbaum scenario characteristic of one-dimensional maps. Other parameters lead to different subharmonic routes indicative of multidimensional behavior, as observed in some experiments.

  1. Dynamics and control of hybrid mechanical systems

    NARCIS (Netherlands)

    Leonov, G.A.; Nijmeijer, H.; Pogromski, A.Y.; Fradkov, A.L.

    2010-01-01

    The papers in this edited volume aim to provide a better understanding of the dynamics and control of a large class of hybrid dynamical systems that are described by different models in different state space domains. They not only cover important aspects and tools for hybrid systems analysis and

  2. Controlling chaos in discontinuous dynamical systems

    International Nuclear Information System (INIS)

    Danca, Marius-F.

    2004-01-01

    In this paper we consider the possibility to implement the technique of changes in the system variables to control the chaos introduced by Gueemez and Matias for continuous dynamical systems to a class of discontinuous dynamical systems. The approach is realized via differential inclusions following the Filippov theory. Three practical examples are considered

  3. Flexible Access Control for Dynamic Collaborative Environments

    NARCIS (Netherlands)

    Dekker, M.A.C.

    2009-01-01

    Access control is used in computer systems to control access to confidential data. In this thesis we focus on access control for dynamic collaborative environments where multiple users and systems access and exchange data in an ad hoc manner. In such environments it is difficult to protect

  4. State estimation for integrated vehicle dynamics control

    NARCIS (Netherlands)

    Zuurbier, J.; Bremmer, P.

    2002-01-01

    This paper discusses a vehicle controller and a state estimator that was implemented and tested in a vehicle equipped with a combined braking and chassis control system to improve handling. The vehicle dynamics controller consists of a feed forward body roll compensation and a feedback stability

  5. Nonlinear dynamics and control of a recycle fixed bed reactor

    DEFF Research Database (Denmark)

    Recke, Bodil; Jørgensen, Sten Bay

    1997-01-01

    The purpose of this paper is twofold. Primarily to describe the dynamic behaviour that can be observed in a fixed bed reactor with recycle of unconverted reactant. Secondly to describe the possibilities of model reduction in order to facilitate control design. Reactant recycle has been shown...... to introduce periodic solution to the fixed bed reactor, a phenomenon which is not seen for the system without the recycle, at least not within the Peclet number range investigated in the present work. The possibility of model reduction by the methods of modal decomposition, and by characteristics...

  6. Modelling of gas-liquid reactors - stability and dynamic behaviour of gas-liquid mass transfer accompanied by irreversible reaction

    NARCIS (Netherlands)

    Elk, E.P. van; Borman, P.C.; Kuipers, J.A.M.; Versteeg, G.F.

    1999-01-01

    The dynamic behaviour and stability of single-phase reacting systems has been investigated thoroughly in the past and design rules for stable operation are available from literature. The dynamic behaviour of gas-liquid processes is considerably more complex and has received relatively little

  7. Modelling of gas-liquid reactors - stability and dynamic behaviour of gas-liquid mass transfer accompanied by irreversible reaction

    NARCIS (Netherlands)

    Elk, van E.P.; Borman, P.C.; Kuipers, J.A.M.; Versteeg, G.F.

    1999-01-01

    The dynamic behaviour and stability of single-phase reacting systems has been investigated thoroughly in the past and design rules for stable operation are available from literature. The dynamic behaviour of gas–liquid processes is considerably more complex and has received relatively little

  8. Agent-based modelling in applied ethology: an exploratory case study of behavioural dynamics in tail biting in pigs

    NARCIS (Netherlands)

    Boumans, I.J.M.M.; Hofstede, G.J.; Bolhuis, J.E.; Boer, de I.J.M.; Bokkers, E.A.M.

    2016-01-01

    Understanding behavioural dynamics in pigs is important to assess pig welfare in current intensive pig production systems. Agent-based modelling (ABM) is an approach to gain insight into behavioural dynamics in pigs, but its use in applied ethology and animal welfare science has been limited so far.

  9. A simulation analysis to characterize the dynamics of vaccinating behaviour on contact networks.

    Science.gov (United States)

    Perisic, Ana; Bauch, Chris T

    2009-05-28

    Human behavior influences infectious disease transmission, and numerous "prevalence-behavior" models have analyzed this interplay. These previous analyses assumed homogeneously mixing populations without spatial or social structure. However, spatial and social heterogeneity are known to significantly impact transmission dynamics and are particularly relevant for certain diseases. Previous work has demonstrated that social contact structure can change the individual incentive to vaccinate, thus enabling eradication of a disease under a voluntary vaccination policy when the corresponding homogeneous mixing model predicts that eradication is impossible due to free rider effects. Here, we extend this work and characterize the range of possible behavior-prevalence dynamics on a network. We simulate transmission of a vaccine-preventable infection through a random, static contact network. Individuals choose whether or not to vaccinate on any given day according to perceived risks of vaccination and infection. We find three possible outcomes for behavior-prevalence dynamics on this type of network: small final number vaccinated and final epidemic size (due to rapid control through voluntary ring vaccination); large final number vaccinated and significant final epidemic size (due to imperfect voluntary ring vaccination), and little or no vaccination and large final epidemic size (corresponding to little or no voluntary ring vaccination). We also show that the social contact structure enables eradication under a broad range of assumptions, except when vaccine risk is sufficiently high, the disease risk is sufficiently low, or individuals vaccinate too late for the vaccine to be effective. For populations where infection can spread only through social contact network, relatively small differences in parameter values relating to perceived risk or vaccination behavior at the individual level can translate into large differences in population-level outcomes such as final size

  10. Bifurcation Control of Chaotic Dynamical Systems

    National Research Council Canada - National Science Library

    Wang, Hua O; Abed, Eyad H

    1992-01-01

    A nonlinear system which exhibits bifurcations, transient chaos, and fully developed chaos is considered, with the goal of illustrating the role of two ideas in the control of chaotic dynamical systems...

  11. Solved problems in dynamical systems and control

    CERN Document Server

    Tenreiro-Machado, J; Valério, Duarte; Galhano, Alexandra M

    2016-01-01

    This book presents a collection of exercises on dynamical systems, modelling and control. Each topic covered includes a summary of the theoretical background, problems with solutions, and further exercises.

  12. Quantum Dynamical Behaviour in Complex Systems - A Semiclassical Approach

    Energy Technology Data Exchange (ETDEWEB)

    Ananth, Nandini [Univ. of California, Berkeley, CA (United States)

    2008-01-01

    One of the biggest challenges in Chemical Dynamics is describing the behavior of complex systems accurately. Classical MD simulations have evolved to a point where calculations involving thousands of atoms are routinely carried out. Capturing coherence, tunneling and other such quantum effects for these systems, however, has proven considerably harder. Semiclassical methods such as the Initial Value Representation (SC-IVR) provide a practical way to include quantum effects while still utilizing only classical trajectory information. For smaller systems, this method has been proven to be most effective, encouraging the hope that it can be extended to deal with a large number of degrees of freedom. Several variations upon the original idea of the SCIVR have been developed to help make these larger calculations more tractable; these range from the simplest, classical limit form, the Linearized IVR (LSC-IVR) to the quantum limit form, the Exact Forward-Backward version (EFB-IVR). In this thesis a method to tune between these limits is described which allows us to choose exactly which degrees of freedom we wish to treat in a more quantum mechanical fashion and to what extent. This formulation is called the Tuning IVR (TIVR). We further describe methodology being developed to evaluate the prefactor term that appears in the IVR formalism. The regular prefactor is composed of the Monodromy matrices (jacobians of the transformation from initial to finial coordinates and momenta) which are time evolved using the Hessian. Standard MD simulations require the potential surfaces and their gradients, but very rarely is there any information on the second derivative. We would like to be able to carry out the SC-IVR calculation without this information too. With this in mind a finite difference scheme to obtain the Hessian on-the-fly is proposed. Wealso apply the IVR formalism to a few problems of current interest. A method to obtain energy eigenvalues accurately for complex

  13. Linking animal population dynamics to alterations in foraging behaviour

    DEFF Research Database (Denmark)

    Nabe-Nielsen, Jacob; Sibly, Richard; Tougaard, Jakob

    Background/Question/Methods The survival of animal populations is strongly influenced by the individuals’ ability to forage efficiently, yet there are few studies of how populations respond when disturbances cause animals to deviate from their natural foraging behavior. Animals that respond...... that are increasingly exposed to noise from ships, wind turbines, etc. In the present study we investigate how the dynamics of the harbor porpoise population (Phocoena phocoena) in the inner Danish waters is influenced by disturbances using an agent- based simulation model. In the model animal movement, and hence...... the animals’ ability to forage efficiently and to sustain their energy intake, is influenced by noise emitted from wind turbines and ships. The energy levels in turn affect their survival. The fine-scale movements of the simulated animals was governed by a spatial memory, which allowed the model to produce...

  14. The effect of grain size on dynamic tensile extrusion behaviour

    Directory of Open Access Journals (Sweden)

    Park Leeju

    2015-01-01

    Full Text Available Dynamic tensile extrusion (DTE tests were conducted on coarse grained and ultrafine grained (UFG OFHC Cu, Interstitial free (IF Steel, and pure Ta. Equal channel angular pressing (ECAP of 16passes with Bc for Cu, IF Steel and 4 passes for Ta was employed to fabricated UFG materials. DTE tests were carried out by launching the sphere samples (Dia. 7.62 mm to the conical extrusion die at a speed of ∼500 m/sec. The fragmentation behavior of the soft-recovered fragments were examined and compared with each other. The DTE fragmentation behavior of CG and UFG was numerically simulated by the LS-DYNA FEM code.

  15. Control of cell behaviour through nanovibrational stimulation: nanokicking

    Science.gov (United States)

    Robertson, Shaun N.; Campsie, Paul; Childs, Peter G.; Madsen, Fiona; Donnelly, Hannah; Henriquez, Fiona L.; Mackay, William G.; Salmerón-Sánchez, Manuel; Tsimbouri, Monica P.; Williams, Craig; Dalby, Matthew J.; Reid, Stuart

    2018-05-01

    Mechanical signals are ubiquitous in our everyday life and the process of converting these mechanical signals into a biological signalling response is known as mechanotransduction. Our understanding of mechanotransduction, and its contribution to vital cellular responses, is a rapidly expanding field of research involving complex processes that are still not clearly understood. The use of mechanical vibration as a stimulus of mechanotransduction, including variation of frequency and amplitude, allows an alternative method to control specific cell behaviour without chemical stimulation (e.g. growth factors). Chemical-independent control of cell behaviour could be highly advantageous for fields including drug discovery and clinical tissue engineering. In this review, a novel technique is described based on nanoscale sinusoidal vibration. Using finite-element analysis in conjunction with laser interferometry, techniques that are used within the field of gravitational wave detection, optimization of apparatus design and calibration of vibration application have been performed. We further discuss the application of nanovibrational stimulation, or `nanokicking', to eukaryotic and prokaryotic cells including the differentiation of mesenchymal stem cells towards an osteoblast cell lineage. Mechanotransductive mechanisms are discussed including mediation through the Rho-A kinase signalling pathway. Optimization of this technique was first performed in two-dimensional culture using a simple vibration platform with an optimal frequency and amplitude of 1 kHz and 22 nm. A novel bioreactor was developed to scale up cell production, with recent research demonstrating that mesenchymal stem cell differentiation can be efficiently triggered in soft gel constructs. This important step provides first evidence that clinically relevant (three-dimensional) volumes of osteoblasts can be produced for the purpose of bone grafting, without complex scaffolds and/or chemical induction

  16. Enterprise Dynamic Access Control (EDAC)

    National Research Council Canada - National Science Library

    Fernandez, Richard

    2005-01-01

    .... Resources can represent software applications, web services and even facility access. An effective access control model should be capable of evaluating resource access based on user characteristics and environmentals...

  17. Theoretical model for investigating the dynamic behaviour of the AST-500 type nuclear heating station reactor

    International Nuclear Information System (INIS)

    Grundmann, U.; Rohde, U.; Naumann, B.

    1985-01-01

    Studies on theoretical simulation of the dynamic behaviour of the AST-500 type reactor primary coolant system are summarized. The first version of a dynamic model in the form of the DYNAST code is described. The DYNAST code is based on a one-dimensional description of the primary coolant circuit including core, draught stack, and intermediate heat exchanger, a vapour dome model, and the point model of neutron kinetics. With the aid of the steady-state computational part of the DYNAST code, studies have been performed on different steady-state operating conditions. Furthermore, some methodological investigations on generalization and improvement of the dynamic model are considered and results presented. (author)

  18. A look at Behaviourism and Perceptual Control Theory in Interface Design

    Science.gov (United States)

    1998-02-01

    behaviours such as response variability, instinctive drift, autoshaping , etc. Perceptual Control Theory (PCT) postulates that behaviours result from the...internal variables. Behaviourism, on the other hand, can not account for variability in responses, instinctive drift, autoshaping , etc. Researchers... Autoshaping . Animals appear to learn without reinforcement. However, conditioning theory speculates that learning results only when reinforcement

  19. Molecular Dynamics Simulations of a Flexible Polyethylene: A Protein-Like Behaviour in a Water Solvent

    CERN Document Server

    Kretov, D A

    2005-01-01

    We used molecular dynamics (MD) simulations to study the density and the temperature behaviour of a flexible polyethylene (PE) subjected to various heating conditions and to investigate the PE chain conformational changes in a water solvent. First, we have considered the influence of the heating process on the final state of the polymeric system and the sensitivity of its thermodynamic characteristics (density, energy, etc.) for different heating regimes. For this purpose three different simulations were performed: fast, moderate, and slow heating. Second, we have investigated the PE chain conformational dynamics in water solvent for various simulation conditions and various configurations of the environment. From the obtained results we have got the pictures of the PE dynamical motions in water. We have observed a protein-like behaviour of the PE chain, like that of the DNA and the proteins in water, and have also estimated the rates of the conformational changes. For the MD simulations we used the optimized...

  20. Dynamical soil-structure interactions: influence of soil behaviour nonlinearities

    International Nuclear Information System (INIS)

    Gandomzadeh, Ali

    2011-01-01

    The interaction of the soil with the structure has been largely explored the assumption of material and geometrical linearity of the soil. Nevertheless, for moderate or strong seismic events, the maximum shear strain can easily reach the elastic limit of the soil behavior. Considering soil-structure interaction, the nonlinear effects may change the soil stiffness at the base of the structure and therefore energy dissipation into the soil. Consequently, ignoring the nonlinear characteristics of the dynamic soil-structure interaction (DSSI) this phenomenon could lead to erroneous predictions of structural response. The goal of this work is to implement a fully nonlinear constitutive model for soils into a numerical code in order to investigate the effect of soil nonlinearity on dynamic soil structure interaction. Moreover, different issues are taken into account such as the effect of confining stress on the shear modulus of the soil, initial static condition, contact elements in the soil-structure interface, etc. During this work, a simple absorbing layer method based on a Rayleigh/Caughey damping formulation, which is often already available in existing Finite Element softwares, is also presented. The stability conditions of the wave propagation problems are studied and it is shown that the linear and nonlinear behavior are very different when dealing with numerical dispersion. It is shown that the 10 points per wavelength rule, recommended in the literature for the elastic media is not sufficient for the nonlinear case. The implemented model is first numerically verified by comparing the results with other known numerical codes. Afterward, a parametric study is carried out for different types of structures and various soil profiles to characterize nonlinear effects. Different features of the DSSI are compared to the linear case: modification of the amplitude and frequency content of the waves propagated into the soil, fundamental frequency, energy dissipation in

  1. Regular self-oscillating and chaotic behaviour of a PID controlled gimbal suspension gyro

    International Nuclear Information System (INIS)

    Perez Polo, Manuel F.; Perez Molina, Manuel

    2004-01-01

    The dynamics of a gyro in gimbal with a PID controller to obtain steady state, self-oscillating and chaotic motion is considered in this paper. The mathematical model of the whole system is deduced from the gyroscope nutation theory and from a feedback control system formed by a PID controller with constrained integral action. The paper shows that the gyro and the associated PID feedback control system have multiple equilibrium points, and from the analysis of a Poincare-Andronov-Hopf bifurcation at the equilibrium points, it is possible to deduce the conditions, which give regular and self-oscillating behaviour. The calculation of the first Lyapunov value is used to predict the motion of the gyro in order to obtain a desired equilibrium point or self-oscillating behaviour. The mechanism of the stability loss of the gyro under small vibrations of the gyro platform and the appearance of chaotic motion is also presented. Numerical simulations are performed to verify the analytical results

  2. Stochastic control theory dynamic programming principle

    CERN Document Server

    Nisio, Makiko

    2015-01-01

    This book offers a systematic introduction to the optimal stochastic control theory via the dynamic programming principle, which is a powerful tool to analyze control problems. First we consider completely observable control problems with finite horizons. Using a time discretization we construct a nonlinear semigroup related to the dynamic programming principle (DPP), whose generator provides the Hamilton–Jacobi–Bellman (HJB) equation, and we characterize the value function via the nonlinear semigroup, besides the viscosity solution theory. When we control not only the dynamics of a system but also the terminal time of its evolution, control-stopping problems arise. This problem is treated in the same frameworks, via the nonlinear semigroup. Its results are applicable to the American option price problem. Zero-sum two-player time-homogeneous stochastic differential games and viscosity solutions of the Isaacs equations arising from such games are studied via a nonlinear semigroup related to DPP (the min-ma...

  3. Transient population dynamics of mosquitoes during sterile male releases: modelling mating behaviour and perturbations of life history parameters.

    Directory of Open Access Journals (Sweden)

    Christopher M Stone

    Full Text Available The release of genetically-modified or sterile male mosquitoes offers a promising form of mosquito-transmitted pathogen control, but the insights derived from our understanding of male mosquito behaviour have not fully been incorporated into the design of such genetic control or sterile-male release methods. The importance of aspects of male life history and mating behaviour for sterile-male release programmes were investigated by projecting a stage-structured matrix model over time. An elasticity analysis of transient dynamics during sterile-male releases was performed to provide insight on which vector control methods are likely to be most synergistic. The results suggest that high mating competitiveness and mortality costs of released males are required before the sterile-release method becomes ineffective. Additionally, if released males suffer a mortality cost, older males should be released due to their increased mating capacity. If released males are of a homogenous size and size-assortative mating occurs in nature, this can lead to an increase in the abundance of large females and reduce the efficacy of the population-suppression effort. At a high level of size-assortative mating, the disease transmission potential of the vector population increases due to male releases, arguing for the release of a heterogeneously-sized male population. The female population was most sensitive to perturbations of density-dependent components of larval mortality and female survivorship and fecundity. These findings suggest source reduction might be a particularly effective complement to mosquito control based on the sterile insect technique (SIT. In order for SIT to realize its potential as a key component of an integrated vector-management strategy to control mosquito-transmitted pathogens, programme design of sterile-male release programmes must account for the ecology, behaviour and life history of mosquitoes. The model used here takes a step in this

  4. Dynamic Frequency Control in Power Networks

    OpenAIRE

    Zhao, Changhong; Mallada Garcia, Enrique; Low, Steven H.

    2016-01-01

    Node controllers in power distribution networks in accordance with embodiments of the invention enable dynamic frequency control. One embodiment includes a node controller comprising a network interface a processor; and a memory containing a frequency control application; and a plurality of node operating parameters describing the operating parameters of a node, where the node is selected from a group consisting of at least one generator node in a power distribution network wherein the proces...

  5. Relating the bipolar spectrum to dysregulation of behavioural activation: a perspective from dynamical modelling.

    Directory of Open Access Journals (Sweden)

    Arno Steinacher

    Full Text Available Bipolar Disorders affect a substantial minority of the population and result in significant personal, social and economic costs. Understanding of the causes of, and consequently the most effective interventions for, this condition is an area requiring development. Drawing upon theories of Bipolar Disorder that propose the condition to be underpinned by dysregulation of systems governing behavioural activation or approach motivation, we present a mathematical model of the regulation of behavioural activation. The model is informed by non-linear, dynamical principles and as such proposes that the transition from "non-bipolar" to "bipolar" diagnostic status corresponds to a switch from mono- to multistability of behavioural activation level, rather than an increase in oscillation of mood. Consistent with descriptions of the behavioural activation or approach system in the literature, auto-activation and auto-inhibitory feedback is inherent within our model. Comparison between our model and empirical, observational data reveals that by increasing the non-linearity dimension in our model, important features of Bipolar Spectrum disorders are reproduced. Analysis from stochastic simulation of the system reveals the role of noise in behavioural activation regulation and indicates that an increase of nonlinearity promotes noise to jump scales from small fluctuations of activation levels to longer lasting, but less variable episodes. We conclude that further research is required to relate parameters of our model to key behavioural and biological variables observed in Bipolar Disorder.

  6. Relating the bipolar spectrum to dysregulation of behavioural activation: a perspective from dynamical modelling.

    Science.gov (United States)

    Steinacher, Arno; Wright, Kim A

    2013-01-01

    Bipolar Disorders affect a substantial minority of the population and result in significant personal, social and economic costs. Understanding of the causes of, and consequently the most effective interventions for, this condition is an area requiring development. Drawing upon theories of Bipolar Disorder that propose the condition to be underpinned by dysregulation of systems governing behavioural activation or approach motivation, we present a mathematical model of the regulation of behavioural activation. The model is informed by non-linear, dynamical principles and as such proposes that the transition from "non-bipolar" to "bipolar" diagnostic status corresponds to a switch from mono- to multistability of behavioural activation level, rather than an increase in oscillation of mood. Consistent with descriptions of the behavioural activation or approach system in the literature, auto-activation and auto-inhibitory feedback is inherent within our model. Comparison between our model and empirical, observational data reveals that by increasing the non-linearity dimension in our model, important features of Bipolar Spectrum disorders are reproduced. Analysis from stochastic simulation of the system reveals the role of noise in behavioural activation regulation and indicates that an increase of nonlinearity promotes noise to jump scales from small fluctuations of activation levels to longer lasting, but less variable episodes. We conclude that further research is required to relate parameters of our model to key behavioural and biological variables observed in Bipolar Disorder.

  7. Specialists' meeting on design features affecting a dynamic behaviour of fast reactor cores. Summary report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1982-01-01

    The purpose of the meeting was to review and discuss the effects induced by changes in some design characteristics on overall performances and transient behaviour of fast reactor cores. The main topics discussed in the four technical sessions were: National Review Presentations. Identification of the key issues to be considered in the following sessions; Effects of design changes on performance characteristics. Kinetics models and codes; Evaluation and interpretation of reactivity coefficients. Kinetics calculations for restrained and free-standing cores; Comparison of the dynamic behaviour of homogeneous and heterogeneous cores.

  8. Specialists' meeting on design features affecting a dynamic behaviour of fast reactor cores. Summary report

    International Nuclear Information System (INIS)

    1982-01-01

    The purpose of the meeting was to review and discuss the effects induced by changes in some design characteristics on overall performances and transient behaviour of fast reactor cores. The main topics discussed in the four technical sessions were: National Review Presentations. Identification of the key issues to be considered in the following sessions; Effects of design changes on performance characteristics. Kinetics models and codes; Evaluation and interpretation of reactivity coefficients. Kinetics calculations for restrained and free-standing cores; Comparison of the dynamic behaviour of homogeneous and heterogeneous cores

  9. The solution of target assignment problem in command and control decision-making behaviour simulation

    Science.gov (United States)

    Li, Ni; Huai, Wenqing; Wang, Shaodan

    2017-08-01

    C2 (command and control) has been understood to be a critical military component to meet an increasing demand for rapid information gathering and real-time decision-making in a dynamically changing battlefield environment. In this article, to improve a C2 behaviour model's reusability and interoperability, a behaviour modelling framework was proposed to specify a C2 model's internal modules and a set of interoperability interfaces based on the C-BML (coalition battle management language). WTA (weapon target assignment) is a typical C2 autonomous decision-making behaviour modelling problem. Different from most WTA problem descriptions, here sensors were considered to be available resources of detection and the relationship constraints between weapons and sensors were also taken into account, which brought it much closer to actual application. A modified differential evolution (MDE) algorithm was developed to solve this high-dimension optimisation problem and obtained an optimal assignment plan with high efficiency. In case study, we built a simulation system to validate the proposed C2 modelling framework and interoperability interface specification. Also, a new optimisation solution was used to solve the WTA problem efficiently and successfully.

  10. Discrete Control Processes, Dynamic Games and Multicriterion Control Problems

    Directory of Open Access Journals (Sweden)

    Dumitru Lozovanu

    2002-07-01

    Full Text Available The discrete control processes with state evaluation in time of dynamical system is considered. A general model of control problems with integral-time cost criterion by a trajectory is studied and a general scheme for solving such classes of problems is proposed. In addition the game-theoretical and multicriterion models for control problems are formulated and studied.

  11. Dynamic control of chaotic resonators

    KAUST Repository

    Di Falco, A.; Bruck, R.; Liu, C.; Muskens, O.; Fratalocchi, Andrea

    2016-01-01

    We report on the all-optical control of chaotic optical resonators based on silicon on insulator (SOI) platform. We show that simple non-chaotic cavities can be tuned to exhibit chaotic behavior via intense optical pump- ing, inducing a local change of refractive index. To this extent we have fabricated a number of devices and demonstrated experimentally and theoretically that chaos can be triggered on demand on an optical chip. © 2016 SPIE.

  12. Dynamic control of chaotic resonators

    KAUST Repository

    Di Falco, A.

    2016-02-16

    We report on the all-optical control of chaotic optical resonators based on silicon on insulator (SOI) platform. We show that simple non-chaotic cavities can be tuned to exhibit chaotic behavior via intense optical pump- ing, inducing a local change of refractive index. To this extent we have fabricated a number of devices and demonstrated experimentally and theoretically that chaos can be triggered on demand on an optical chip. © 2016 SPIE.

  13. Role of controllability in optimizing quantum dynamics

    International Nuclear Information System (INIS)

    Wu Rebing; Hsieh, Michael A.; Rabitz, Herschel

    2011-01-01

    This paper reveals an important role that controllability plays in the complexity of optimizing quantum control dynamics. We show that the loss of controllability generally leads to multiple locally suboptimal controls when gate fidelity in a quantum control system is maximized, which does not happen if the system is controllable. Such local suboptimal controls may attract an optimization algorithm into a local trap when a global optimal solution is sought, even if the target gate can be perfectly realized. This conclusion results from an analysis of the critical topology of the corresponding quantum control landscape, which refers to the gate fidelity objective as a functional of the control fields. For uncontrollable systems, due to SU(2) and SU(3) dynamical symmetries, the control landscape corresponding to an implementable target gate is proven to possess multiple locally optimal critical points, and its ruggedness can be further increased if the target gate is not realizable. These results imply that the optimization of quantum dynamics can be seriously impeded when operating with local search algorithms under these conditions, and thus full controllability is demanded.

  14. Management Control Systems, Evaluative Style, and Behaviour : Exploring the Concept and Behavioural Consequences of Evaluative Style

    NARCIS (Netherlands)

    J. Noeverman (Jan)

    2007-01-01

    textabstractOrganisations develop and implement performance measurement and performance evaluation systems to motivate employees to take actions that -in the end- improve organisational (financial) performance. But do these systems really influence employee behaviour as intended? This thesis shows

  15. Adaptive Control of Exoskeleton Robots for Periodic Assistive Behaviours Based on EMG Feedback Minimisation

    Science.gov (United States)

    Peternel, Luka; Noda, Tomoyuki; Petrič, Tadej; Ude, Aleš; Morimoto, Jun; Babič, Jan

    2016-01-01

    In this paper we propose an exoskeleton control method for adaptive learning of assistive joint torque profiles in periodic tasks. We use human muscle activity as feedback to adapt the assistive joint torque behaviour in a way that the muscle activity is minimised. The user can then relax while the exoskeleton takes over the task execution. If the task is altered and the existing assistive behaviour becomes inadequate, the exoskeleton gradually adapts to the new task execution so that the increased muscle activity caused by the new desired task can be reduced. The advantage of the proposed method is that it does not require biomechanical or dynamical models. Our proposed learning system uses Dynamical Movement Primitives (DMPs) as a trajectory generator and parameters of DMPs are modulated using Locally Weighted Regression. Then, the learning system is combined with adaptive oscillators that determine the phase and frequency of motion according to measured Electromyography (EMG) signals. We tested the method with real robot experiments where subjects wearing an elbow exoskeleton had to move an object of an unknown mass according to a predefined reference motion. We further evaluated the proposed approach on a whole-arm exoskeleton to show that it is able to adaptively derive assistive torques even for multiple-joint motion. PMID:26881743

  16. Adaptive Control of Exoskeleton Robots for Periodic Assistive Behaviours Based on EMG Feedback Minimisation.

    Science.gov (United States)

    Peternel, Luka; Noda, Tomoyuki; Petrič, Tadej; Ude, Aleš; Morimoto, Jun; Babič, Jan

    2016-01-01

    In this paper we propose an exoskeleton control method for adaptive learning of assistive joint torque profiles in periodic tasks. We use human muscle activity as feedback to adapt the assistive joint torque behaviour in a way that the muscle activity is minimised. The user can then relax while the exoskeleton takes over the task execution. If the task is altered and the existing assistive behaviour becomes inadequate, the exoskeleton gradually adapts to the new task execution so that the increased muscle activity caused by the new desired task can be reduced. The advantage of the proposed method is that it does not require biomechanical or dynamical models. Our proposed learning system uses Dynamical Movement Primitives (DMPs) as a trajectory generator and parameters of DMPs are modulated using Locally Weighted Regression. Then, the learning system is combined with adaptive oscillators that determine the phase and frequency of motion according to measured Electromyography (EMG) signals. We tested the method with real robot experiments where subjects wearing an elbow exoskeleton had to move an object of an unknown mass according to a predefined reference motion. We further evaluated the proposed approach on a whole-arm exoskeleton to show that it is able to adaptively derive assistive torques even for multiple-joint motion.

  17. Adaptive Control of Exoskeleton Robots for Periodic Assistive Behaviours Based on EMG Feedback Minimisation.

    Directory of Open Access Journals (Sweden)

    Luka Peternel

    Full Text Available In this paper we propose an exoskeleton control method for adaptive learning of assistive joint torque profiles in periodic tasks. We use human muscle activity as feedback to adapt the assistive joint torque behaviour in a way that the muscle activity is minimised. The user can then relax while the exoskeleton takes over the task execution. If the task is altered and the existing assistive behaviour becomes inadequate, the exoskeleton gradually adapts to the new task execution so that the increased muscle activity caused by the new desired task can be reduced. The advantage of the proposed method is that it does not require biomechanical or dynamical models. Our proposed learning system uses Dynamical Movement Primitives (DMPs as a trajectory generator and parameters of DMPs are modulated using Locally Weighted Regression. Then, the learning system is combined with adaptive oscillators that determine the phase and frequency of motion according to measured Electromyography (EMG signals. We tested the method with real robot experiments where subjects wearing an elbow exoskeleton had to move an object of an unknown mass according to a predefined reference motion. We further evaluated the proposed approach on a whole-arm exoskeleton to show that it is able to adaptively derive assistive torques even for multiple-joint motion.

  18. Study on Dynamic Behaviour of Wishbone Suspension System

    International Nuclear Information System (INIS)

    Kamal, M; Rahman, M M

    2012-01-01

    This paper presents the characteristic model of the wishbone suspension system using the quarter car model approach. Suspension system in an automobile provides vehicle control and passenger comfort by providing isolation from road disturbances. This makes it essential that the detailed behavior of suspension should be known to optimize the performance. A kinetic study is performed using multi body system (MBS) analysis. The dirt road profile is considered as an applied loading. The spring constant, damping coefficient and sprung mass are studied on the performance of the suspension system. It can be observed that the spring constant is inversely related with time required to return to initial position and the amount of deformations. The damping ratio affects the suppression of spring oscillations, beyond a certain limit damping ration has the negligible effect. Sprung mass effected the equilibrium position of the suspension system with a small effect on its oscillation behavior. It is shown that the spring constant, damping ratio and sprung mass are significant parameters to design the suspension system. This study is essential for complete understanding of working of the suspension system and a future study with real geometries.

  19. Deriving Behaviour of Hodgkin Huxley model with fever dynamics: A computational study

    Directory of Open Access Journals (Sweden)

    Hasan ESKALEN

    2017-10-01

    Full Text Available A single neuron can be modeled by the set of differential equations. Hodgkin-Huxley (HH model, the one of the most famous neuron model, can be considered as a dynamical system with four independent variables. Here we studied to reduce the number of differential equation required for conductance based HH model under strong inhibitory noise. Exponential Integrate and Fire (EIF model, one independent variable, is used as a reduced model of HH model by using current-voltage (I-V curve of the original model. The required reduction parameters are determined from this curve. The behaviour of HH model and its reduced EIF (rEIF model are in good agreement in sub-threshold level. Above-threshold behaviour of reduced EIF model and original model compared in terms of threshold voltage under strong inhibitory noise. Our numerical simulations clearly show that sub-threshold behaviour of HH model perfectly reduced to rEIF model.

  20. Experience with dynamic material control subsystems

    International Nuclear Information System (INIS)

    Severe, W.R.; Hagen, J.; Siebelist, R.; Wagner, R.P.; Olson, W.M.

    1977-01-01

    Operation of a Dynamic Material Control (DYMAC) prototype system has yielded some useful information for installing the final system. We discovered a bias between two methods for measuring filtrates. Evaluation of a unit process dynamic balance brought to light an operating procedure that weakens the accountability goals of the DYMAC system. We were able to correct both situations for the final system and learned that we must regularly monitor the system once it is operational for similar discrepancies

  1. Chaos control of Chen chaotic dynamical system

    International Nuclear Information System (INIS)

    Yassen, M.T.

    2003-01-01

    This paper is devoted to study the problem of controlling chaos in Chen chaotic dynamical system. Two different methods of control, feedback and nonfeedback methods are used to suppress chaos to unstable equilibria or unstable periodic orbits (UPO). The Lyapunov direct method and Routh-Hurwitz criteria are used to study the conditions of the asymptotic stability of the steady states of the controlled system. Numerical simulations are presented to show these results

  2. Sign and Symptom and Ability to Control Violent Behaviour with Music Therapy and Rational Emotive Cognitive Behaviour Therapy

    Directory of Open Access Journals (Sweden)

    Heri Setiawan

    2015-10-01

    Full Text Available Introduction: Prevalence of violence is highly occur in mental disorders clients at psychiatric hospitals. The impact is injure to others. This research aims to examine the effectiveness of music therapy and RECBT to sign and symptom and ability to control violent behaviour. Methods: Quasi-experimental research design with a sample of 64 respondents. Result: The study found a decrease symptoms of violent behaviour, ability to control violent behavior include relaxation, change negative thingking, irational belief, and negative behavior have increased significantly than the clients that did not receiving therapy. Discussion: Music therapy and RECBT is recommended as a therapeutic nursing at the client’s violent behaviour. Key Word: violent, sign and simptom, ability, music therapy, RECBT

  3. Rumination-focused cognitive behaviour therapy vs. cognitive behaviour therapy for depression: study protocol for a randomised controlled superiority trial.

    Science.gov (United States)

    Hvenegaard, Morten; Watkins, Ed R; Poulsen, Stig; Rosenberg, Nicole K; Gondan, Matthias; Grafton, Ben; Austin, Stephen F; Howard, Henriette; Moeller, Stine B

    2015-08-11

    Cognitive behavioural therapy is an effective treatment for depression. However, one third of the patients do not respond satisfactorily, and relapse rates of around 30 % within the first post-treatment year were reported in a recent meta-analysis. In total, 30-50 % of remitted patients present with residual symptoms by the end of treatment. A common residual symptom is rumination, a process of recurrent negative thinking and dwelling on negative affect. Rumination has been demonstrated as a major factor in vulnerability to depression, predicting the onset, severity, and duration of future depression. Rumination-focused cognitive behavioural therapy is a psychotherapeutic treatment targeting rumination. Because rumination plays a major role in the initiation and maintenance of depression, targeting rumination with rumination-focused cognitive behavioural therapy may be more effective in treating depression and reducing relapse than standard cognitive behavioural therapy. This study is a two-arm pragmatic randomised controlled superiority trial comparing the effectiveness of group-based rumination-focused cognitive behaviour therapy with the effectiveness of group-based cognitive behavioural therapy for treatment of depression. One hundred twenty-eight patients with depression will be recruited from and given treatment in an outpatient service at a psychiatric hospital in Denmark. Our primary outcome will be severity of depressive symptoms (Hamilton Rating Scale for Depression) at completion of treatment. Secondary outcomes will be level of rumination, worry, anxiety, quality of life, behavioural activation, experimental measures of cognitive flexibility, and emotional attentional bias. A 6-month follow-up is planned and will include the primary outcome measure and assessment of relapse. The clinical outcome of this trial may guide clinicians to decide on the merits of including rumination-focused cognitive behavioural therapy in the treatment of depression in

  4. Synchronisation effects on the behavioural performance and information dynamics of a simulated minimally cognitive robotic agent.

    Science.gov (United States)

    Moioli, Renan C; Vargas, Patricia A; Husbands, Phil

    2012-09-01

    Oscillatory activity is ubiquitous in nervous systems, with solid evidence that synchronisation mechanisms underpin cognitive processes. Nevertheless, its informational content and relationship with behaviour are still to be fully understood. In addition, cognitive systems cannot be properly appreciated without taking into account brain-body- environment interactions. In this paper, we developed a model based on the Kuramoto Model of coupled phase oscillators to explore the role of neural synchronisation in the performance of a simulated robotic agent in two different minimally cognitive tasks. We show that there is a statistically significant difference in performance and evolvability depending on the synchronisation regime of the network. In both tasks, a combination of information flow and dynamical analyses show that networks with a definite, but not too strong, propensity for synchronisation are more able to reconfigure, to organise themselves functionally and to adapt to different behavioural conditions. The results highlight the asymmetry of information flow and its behavioural correspondence. Importantly, it also shows that neural synchronisation dynamics, when suitably flexible and reconfigurable, can generate minimally cognitive embodied behaviour.

  5. Modelling of the turbo-generator groups dynamical behaviour. Application to the ARABELLE turbine of the N4 1400 MW unit

    International Nuclear Information System (INIS)

    Bediou, J.

    1993-01-01

    Simulation of the dynamical behaviour of the EDF turbogenerator groups is based on developments concerning bearing behaviour and shaft line dynamics. A provisional model for the ARABELLE turbine dynamic behaviour is derived. The detailed representation of all the components allows for a fine analysis of the different effects and the evaluation of the stresses transmitted to the structure in anomalistic operating conditions

  6. Approaches to Learning to Control Dynamic Uncertainty

    Directory of Open Access Journals (Sweden)

    Magda Osman

    2015-10-01

    Full Text Available In dynamic environments, when faced with a choice of which learning strategy to adopt, do people choose to mostly explore (maximizing their long term gains or exploit (maximizing their short term gains? More to the point, how does this choice of learning strategy influence one’s later ability to control the environment? In the present study, we explore whether people’s self-reported learning strategies and levels of arousal (i.e., surprise, stress correspond to performance measures of controlling a Highly Uncertain or Moderately Uncertain dynamic environment. Generally, self-reports suggest a preference for exploring the environment to begin with. After which, those in the Highly Uncertain environment generally indicated they exploited more than those in the Moderately Uncertain environment; this difference did not impact on performance on later tests of people’s ability to control the dynamic environment. Levels of arousal were also differentially associated with the uncertainty of the environment. Going beyond behavioral data, our model of dynamic decision-making revealed that, in actual fact, there was no difference in exploitation levels between those in the highly uncertain or moderately uncertain environments, but there were differences based on sensitivity to negative reinforcement. We consider the implications of our findings with respect to learning and strategic approaches to controlling dynamic uncertainty.

  7. Relationships between perceived teachers' controlling behaviour, psychological need thwarting, anger and bullying behaviour in high-school students.

    Science.gov (United States)

    Hein, Vello; Koka, Andre; Hagger, Martin S

    2015-07-01

    We tested a model of the associations between students' perceptions of their physical education teacher's controlling behaviour, perceptions of basic psychological need thwarting, anger and bullying behaviour. School students (N = 602; M age = 12.88, SD = 1.37) from 10 schools completed measures of perceived teachers' controlling behaviour and perceived thwarting of the psychological needs for autonomy, competence, and relatedness in physical education context and self-reported bullying and anger. A well-fitting structural equation model demonstrated that students' perceptions of the negative conditional regard and intimidation exhibited by the teacher had significant indirect effect on students' feelings of anger and bullying behaviour through the perceived psychological need thwarting in physical education. Findings suggest that physical education teachers who avoid the use of negative conditional regard and intimidation in their classes have students who perceive less need thwarting and report less bullying behaviour. Copyright © 2015 The Foundation for Professionals in Services for Adolescents. Published by Elsevier Ltd. All rights reserved.

  8. SALLY - a computer programme for the calculation of the dynamical behaviour of a cooling channel

    International Nuclear Information System (INIS)

    Reiche, C.; Ziegenbein, D.

    1978-12-01

    This report describes the mathematical-physical fundamentals and provides a user's manual as well as some test examples for the programme SALLY. SALLY is suitable for the calculation of the dynamical behaviour of a cooling channel under following conditions: point-kinetics, heat transfer in the fuel in radial direction only, reactivity feedback, simple model of the first cooling cycle. Reactivity, coolant inlet temperature or coolant velocity can be disturbed. (author)

  9. Design factors affecting dynamic behaviour of fast reactor cores. UK review paper

    Energy Technology Data Exchange (ETDEWEB)

    Brindley, K W [National Nuclear Corporation Ltd., Risley, Warrington (United Kingdom); Perks, M A [United Kingdom Atomic Energy Authority, Risley, Warrington (United Kingdom)

    1982-01-01

    This paper summarises the consideration that has been given in the UK to the following factors that affect the dynamic behaviour of fast reactor cores: fuel design - Pu/u homogeneity, fuel expansion, fuel-clad gaps, uranium fraction. Structural response - CR supports, diagrid, sub-assembly bowing sodium expansion coefficients - low void cores including heterogenous cores. Calculational methods and models are outlined and some experimental results are discussed. (author)

  10. Controlling Chemistry in Dynamic Nanoscale Systems

    DEFF Research Database (Denmark)

    Jesorka, Aldo; Lizana, Ludvig; Konkoli, Zoran

    2011-01-01

    Spatial organization and shape dynamics are inherent properties of biological cells and cell interiors. There are strong indications that these features are important for the in vivo control of reaction parameters in biochemical transformations. Nanofluidic model devices founded on surfactant...... of the concept. Controlled release of chol-DNA molecules from SU-8 surfaces gives the possibility to dynamically change surface and/or solution properties in micro and nanoreactor applications, opening access to stable 2D chemistry on surface-based devices with potential for easy interfacing with conventional...

  11. Fatigue behaviour of core-spun yarns containing filament by means of cyclic dynamic loading

    Science.gov (United States)

    Esin, S.; Osman, B.

    2017-10-01

    The behaviour of yarns under dynamic loading is important that leads to understand the growth characteristics which is exposed to repetitive loadings during usage of fabric made from these yarns. Fabric growth is undesirable property that originated from low resilience characteristics of fabric. In this study, the effects of the filament fineness and yarn linear density on fatigue behaviour of rigid-core spun yarns were determined. Cotton covered yarns containing different filament fineness of polyester (PET) draw textured yarns (DTY) (100d/36f, 100d/96f, 100d/144f, 100d/192f and 100d/333f) and yarn linear densities (37 tex, 30 tex, 25 tex and 21 tex) were manufactured by using a modified ring spinning system at the same spinning parameters. Repetitive loads were applied for 25 cycles at levels between 0.1 and 3 N. Dynamic modulus and dynamic strain of yarn samples were analyzed statistically. Results showed that filament fineness and yarn linear density have significance effect on dynamic modulus and dynamic strain after cyclic loading.

  12. Dynamic behaviour of dc double anode plasma torch at atmospheric pressure

    International Nuclear Information System (INIS)

    Tu, X; Cheron, B G; Yan, J H; Cen, K F

    2007-01-01

    An original dc double anode plasma torch which provides a long-time and highly stable atmospheric plasma jet has been devised for the purpose of hazardous waste treatment. The arc fluctuations and dynamic behaviour of the argon and argon-nitrogen plasma jets under different operating conditions have been investigated by means of classical tools, such as the statistic method, fast Fourier transform (FFT) and correlation analysis. In our experiments, the takeover mode is identified as the fluctuation characteristic of the argon plasma jet while the restrike mode is typical in the argon-nitrogen plasma dynamic behaviour. In the case of pure argon, the FFT and correlation calculation results of electrical signals exhibit the only characteristic frequency of 150 Hz, which originates from the torch power and is independent of any change in the operating conditions. It indicates that the nature of fluctuations in an argon plasma jet is mainly induced by the undulation of the tri-phase rectified power supply. In contrast, besides the same low frequency bulk fluctuation, the dynamic behaviour of the argon-nitrogen plasma jet at high frequency (4.1 kHz) is ascribed to the rapid motion of both arc roots on the anode surface. In addition, it is found that each arc root attachment is rather diffused than located at a fixed position on the anode wall in the argon plasma jet, while constricted arc roots occur when nitrogen is added into argon as the plasma working gas

  13. 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.

  14. ¬Mesenchymal Stem Cell Fate: Applying Biomaterials for Control of Stem Cell Behaviour

    Directory of Open Access Journals (Sweden)

    Hilary Jane Anderson

    2016-05-01

    Full Text Available Mesenchymal Stem Cell Fate: Applying Biomaterials for Control of Stem Cell BehaviourHilary J Anderson1, Jugal Kishore Sahoo2, Rein V Ulijn2,3, Matthew J Dalby1*1 Centre for Cell Engineering, University of Glasgow, Glasgow, UK.2 Technology and Innovation centre, Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow, UK. 3 Advanced Science Research Centre (ASRC and Hunter College, City University of New York, NY 10031, NY, USA. Correspondence:*Hilary Andersonh.anderson.1@research.gla.ac.ukKeywords: mesenchymal stem cells, bioengineering, materials synthesis, nanotopography, stimuli responsive material□AbstractThe materials pipeline for biomaterials and tissue engineering applications is under continuous development. Specifically, there is great interest in the use of designed materials in the stem cell arena as materials can be used to manipulate the cells providing control of behaviour. This is important as the ability to ‘engineer’ complexity and subsequent in vitro growth of tissues and organs is a key objective for tissue engineers. This review will describe the nature of the materials strategies, both static and dynamic, and their influence specifically on mesenchymal stem cell fate.

  15. Dynamics of tactical behaviour in association football when manipulating players' space of interaction.

    Directory of Open Access Journals (Sweden)

    Angel Ric

    Full Text Available The analysis of positional data in association football allows the spatial distribution of players during matches to be described in order to improve the understanding of tactical-related constraints on the behavioural dynamics of players. The aim of this study was to identify how players' spatial restrictions affected the exploratory tactical behaviour and constrained the perceptual-motor workspace of players in possession of the ball, as well as inter-player passing interactions. Nineteen professional outfield male players were divided into two teams of 10 and 9 players, respectively. The game was played under three spatial constraints: a players were not allowed to move out of their allocated zones, except for the player in possession of the ball; b players were allowed to move to an adjacent zone, and; c non-specific spatial constraints. Positional data was captured using a 5 Hz interpolated GPS tracking system and used to define the configuration states of players for each second in time. The configuration state comprised 37 categories derived from tactical actions, distance from the nearest opponent, distance from the target and movement speed. Notational analysis of players in possession of the ball allowed the mean time of ball possession and the probabilities of passing the ball between players to be calculated. The results revealed that the players' long-term exploratory behaviour decreased and their short-term exploration increased when restricting their space of interaction. Relaxing players' positional constraints seemed to increase the speed of ball flow dynamics. Allowing players to move to an adjacent sub-area increased the probabilities of interaction with the full-back during play build-up. The instability of the coordinative state defined by being free from opponents when players had the ball possession was an invariant feature under all three task constraints. By allowing players to move to adjacent sub-areas, the

  16. Dynamic vulnerability assessment and intelligent control for sustainable power systems

    CERN Document Server

    Gonzalez-Longatt, Francisco

    2018-01-01

    Identifying, assessing, and mitigating electric power grid vulnerabilities is a growing focus in short-term operational planning of power systems. Through illustrated application, this important guide surveys state-of-the-art methodologies for the assessment and enhancement of power system security in short-term operational planning and real-time operation. The methodologies employ advanced methods from probabilistic theory, data mining, artificial intelligence, and optimization, to provide knowledge-based support for monitoring, control (preventive and corrective), and decision making tasks. Key features: Introduces behavioural recognition in wide-area monitoring and security constrained optimal power flow for intelligent control and protection and optimal grid management. Provides in-depth understanding of risk-based reliability and security assessment, dynamic vulnerability as essment methods, supported by the underpinning mathematics. Develops expertise in mitigation techniques using intelligent protect...

  17. Controlling Complex Systems and Developing Dynamic Technology

    Science.gov (United States)

    Avizienis, Audrius Victor

    In complex systems, control and understanding become intertwined. Following Ilya Prigogine, we define complex systems as having control parameters which mediate transitions between distinct modes of dynamical behavior. From this perspective, determining the nature of control parameters and demonstrating the associated dynamical phase transitions are practically equivalent and fundamental to engaging with complexity. In the first part of this work, a control parameter is determined for a non-equilibrium electrochemical system by studying a transition in the morphology of structures produced by an electroless deposition reaction. Specifically, changing the size of copper posts used as the substrate for growing metallic silver structures by the reduction of Ag+ from solution under diffusion-limited reaction conditions causes a dynamical phase transition in the crystal growth process. For Cu posts with edge lengths on the order of one micron, local forces promoting anisotropic growth predominate, and the reaction produces interconnected networks of Ag nanowires. As the post size is increased above 10 microns, the local interfacial growth reaction dynamics couple with the macroscopic diffusion field, leading to spatially propagating instabilities in the electrochemical potential which induce periodic branching during crystal growth, producing dendritic deposits. This result is interesting both as an example of control and understanding in a complex system, and as a useful combination of top-down lithography with bottom-up electrochemical self-assembly. The second part of this work focuses on the technological development of devices fabricated using this non-equilibrium electrochemical process, towards a goal of integrating a complex network as a dynamic functional component in a neuromorphic computing device. Self-assembled networks of silver nanowires were reacted with sulfur to produce interfacial "atomic switches": silver-silver sulfide junctions, which exhibit

  18. A simulation analysis to characterize the dynamics of vaccinating behaviour on contact networks

    Directory of Open Access Journals (Sweden)

    Bauch Chris T

    2009-05-01

    Full Text Available Abstract Background Human behavior influences infectious disease transmission, and numerous "prevalence-behavior" models have analyzed this interplay. These previous analyses assumed homogeneously mixing populations without spatial or social structure. However, spatial and social heterogeneity are known to significantly impact transmission dynamics and are particularly relevant for certain diseases. Previous work has demonstrated that social contact structure can change the individual incentive to vaccinate, thus enabling eradication of a disease under a voluntary vaccination policy when the corresponding homogeneous mixing model predicts that eradication is impossible due to free rider effects. Here, we extend this work and characterize the range of possible behavior-prevalence dynamics on a network. Methods We simulate transmission of a vaccine-prevetable infection through a random, static contact network. Individuals choose whether or not to vaccinate on any given day according to perceived risks of vaccination and infection. Results We find three possible outcomes for behavior-prevalence dynamics on this type of network: small final number vaccinated and final epidemic size (due to rapid control through voluntary ring vaccination; large final number vaccinated and significant final epidemic size (due to imperfect voluntary ring vaccination, and little or no vaccination and large final epidemic size (corresponding to little or no voluntary ring vaccination. We also show that the social contact structure enables eradication under a broad range of assumptions, except when vaccine risk is sufficiently high, the disease risk is sufficiently low, or individuals vaccinate too late for the vaccine to be effective. Conclusion For populations where infection can spread only through social contact network, relatively small differences in parameter values relating to perceived risk or vaccination behavior at the individual level can translate into large

  19. Control theory of digitally networked dynamic systems

    CERN Document Server

    Lunze, Jan

    2013-01-01

    The book gives an introduction to networked control systems and describes new modeling paradigms, analysis methods for event-driven, digitally networked systems, and design methods for distributed estimation and control. Networked model predictive control is developed as a means to tolerate time delays and packet loss brought about by the communication network. In event-based control the traditional periodic sampling is replaced by state-dependent triggering schemes. Novel methods for multi-agent systems ensure complete or clustered synchrony of agents with identical or with individual dynamic

  20. Design and control of swarm dynamics

    CERN Document Server

    Bouffanais, Roland

    2016-01-01

    The book is about the key elements required for designing, building and controlling effective artificial swarms comprised of multiple moving physical agents. Therefore this book presents the fundamentals of each of those key elements in the particular frame of dynamic swarming, specifically exposing the profound connections between these elements and establish some general design principles for swarming behaviors. This scientific endeavor requires an inter-disciplinary approach: biomimetic inspiration from ethology and ecology, study of social information flow, analysis of temporal and adaptive signaling network of interaction, considerations of control of networked real-time systems, and lastly, elements of complex adaptive dynamical systems. This book offers a completely new perspective on the scientific understanding of dynamic collective behaviors thanks to its multi-disciplinary approach and its focus on artificial swarm of physical agents. Two of the key problems in understanding the emergence of swarm ...

  1. 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.

  2. 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)

  3. Cognitive Control: Dynamic, Sustained, and Voluntary Influences

    Science.gov (United States)

    Fernandez-Duque, Diego; Knight, MaryBeth

    2008-01-01

    The cost of incongruent stimuli is reduced when conflict is expected. This series of experiments tested whether this improved performance is due to repetition priming or to enhanced cognitive control. Using a paradigm in which Word and Number Stroop alternated every trial, Experiment 1 assessed dynamic trial-to-trial changes. Incongruent trials…

  4. A perspective on stage dynamics and control

    NARCIS (Netherlands)

    Butler, H.

    2008-01-01

    In the semiconductor industry, a wafer stepper is used to expose the pattern on a mask (‘reticle’) onto a wafer. Accurate positioning of the reticle and the wafer is of crucial importance for creating a working IC. This paper reflects on the stage dynamics and control design in Stepper technology,

  5. Direct Optimal Control of Duffing Dynamics

    Science.gov (United States)

    Oz, Hayrani; Ramsey, John K.

    2002-01-01

    The "direct control method" is a novel concept that is an attractive alternative and competitor to the differential-equation-based methods. The direct method is equally well applicable to nonlinear, linear, time-varying, and time-invariant systems. For all such systems, the method yields explicit closed-form control laws based on minimization of a quadratic control performance measure. We present an application of the direct method to the dynamics and optimal control of the Duffing system where the control performance measure is not restricted to a quadratic form and hence may include a quartic energy term. The results we present in this report also constitute further generalizations of our earlier work in "direct optimal control methodology." The approach is demonstrated for the optimal control of the Duffing equation with a softening nonlinear stiffness.

  6. Chaotic behaviour in the non-linear optimal control of unilaterally contacting building systems during earthquakes

    CERN Document Server

    Liolios, A

    2003-01-01

    The paper presents a new numerical approach for a non-linear optimal control problem arising in earthquake civil engineering. This problem concerns the elastoplastic softening-fracturing unilateral contact between neighbouring buildings during earthquakes when Coulomb friction is taken into account under second-order instabilizing effects. So, the earthquake response of the adjacent structures can appear instabilities and chaotic behaviour. The problem formulation presented here leads to a set of equations and inequalities, which is equivalent to a dynamic hemivariational inequality in the way introduced by Panagiotopoulos [Hemivariational Inequalities. Applications in Mechanics and Engineering, Springer-Verlag, Berlin, 1993]. The numerical procedure is based on an incremental problem formulation and on a double discretization, in space by the finite element method and in time by the Wilson-theta method. The generally non-convex constitutive contact laws are piecewise linearized, and in each time-step a non-c...

  7. SSI on the Dynamic Behaviour of a Historical Masonry Building: Experimental versus Numerical Results

    Directory of Open Access Journals (Sweden)

    Francesca Ceroni

    2014-11-01

    Full Text Available A reliable procedure to identify the dynamic behaviour of existing masonry buildings is described in the paper, referring to a representative case study: a historical masonry palace located in Benevento (Italy. Since the building has been equipped with a permanent dynamic monitoring system by the Department of Civil Protection, some of the recorded data, acquired in various operating conditions, have been analysed with basic instruments of the Operational Modal Analysis in order to identify the main eigenfrequencies and vibration modes of the structure. The obtained experimental results have been compared to the numerical outcomes provided by three detailed Finite Element (FE models of the building. The influence of Soil-Structure Interaction (SSI has been also introduced in the FE model by a sub-structure approach where concentrated springs were placed at the base of the building to simulate the effect of soil and foundation on the global dynamic behaviour of the structure. The obtained results evidence that subsoil cannot a priori be disregarded in identifying the dynamic response of the building.

  8. Quantitative Analysis of Dynamic Behaviours of Rural Areas at Provincial Level Using Public Data of Gross Domestic Product

    DEFF Research Database (Denmark)

    Chen, Yi; Zhang, Guangfeng; Li, Yiyang

    2013-01-01

    A spatial approach that incorporates three economic components and one environmental factor has been developed to evaluate the dynamic behaviours of the rural areas at a provincial level. An artificial fish swarm algorithm with variable population size (AFSAVP) is proposed for the spatial problem......, and the results have shown that the modelling method based on GDP data can assess the spatial dynamic behaviours and can be taken as an operational tool for the policy planners....

  9. Developing a taxonomy of coordination behaviours in nuclear power plant control rooms during emergencies.

    Science.gov (United States)

    Wang, Dunxing; Gao, Qin; Li, Zhizhong; Song, Fei; Ma, Liang

    2017-12-01

    This study aims to develop a taxonomy of coordination behaviours during emergencies in nuclear power plants (NPPs). We summarised basic coordination behaviours from literature in aviation, health care and nuclear field and identified coordination behaviours specific to the nuclear domain by interviewing and surveying control crew operators. The established taxonomy includes 7 workflow stages and 24 basic coordination behaviours. To evaluate the reliability and feasibility of the taxonomy, we analysed 12 videos of operators' training sessions by coding coordination behaviours with the taxonomy and the inter-rater reliability was acceptable. Further analysis of the frequency, the duration and the direction of the coordination behaviours revealed four coordination problems. This taxonomy provides a foundation of systematic observation of coordination behaviours among NPP crews, advances researchers' understanding of the coordination mechanism during emergencies in NPPs and facilitate the possibility to deepen the understanding of the relationships between coordination behaviours and team performance. Practitioner Summary: A taxonomy of coordination behaviours during emergencies in nuclear power plants was developed. Reliability and feasibility of the taxonomy was verified through the analysis of 12 training sessions. The taxonomy can serve as an observation system for analysis of coordination behaviours and help to identify coordination problems of control crews.

  10. Theoretical study of laser feedback interferometry for dynamical material's behaviour studies

    International Nuclear Information System (INIS)

    Le-Barbier, Laura

    2017-01-01

    The purpose of this thesis is to study the feasibility of optical feedback interferometry (OFI) for measuring velocities for dynamical material's behaviour studies. Dynamical material's behaviour studies permit to analyse the shocked material when subjects to shocks (laser shocks, isentropic compression, projectiles, etc.). In these conditions, we seek to measure velocities up to 10 km/s. The OFI technique is regularly used as an embedded system to measure slow velocities in various fields. However, very few studies have been performed for determining velocities measurement limits for this system. As a matter of fact, the optical feedback induces nonlinear effects into the laser's cavity: it disrupts the laser's emitted optical power. Depending on the optical feedback strength, the laser can show chaotic behaviour, then it is no longer possible to get the information for the target's velocity or displacement regarding the signal. In this study, we have been developing mathematical models and performing a wide range of numerical simulations to study the performances and the limits of the OFI technique. We have been also studying the influence of the targets reflectivity, the length and the modulation frequency of the external cavity. (author) [fr

  11. The influence of social norms on the dynamics of vaccinating behaviour for paediatric infectious diseases.

    Science.gov (United States)

    Oraby, Tamer; Thampi, Vivek; Bauch, Chris T

    2014-04-07

    Mathematical models that couple disease dynamics and vaccinating behaviour often assume that the incentive to vaccinate disappears if disease prevalence is zero. Hence, they predict that vaccine refusal should be the rule, and elimination should be difficult or impossible. In reality, countries with non-mandatory vaccination policies have usually been able to maintain elimination or very low incidence of paediatric infectious diseases for long periods of time. Here, we show that including injunctive social norms can reconcile such behaviour-incidence models to observations. Adding social norms to a coupled behaviour-incidence model enables the model to better explain pertussis vaccine uptake and disease dynamics in the UK from 1967 to 2010, in both the vaccine-scare years and the years of high vaccine coverage. The model also illustrates how a vaccine scare can perpetuate suboptimal vaccine coverage long after perceived risk has returned to baseline, pre-vaccine-scare levels. However, at other model parameter values, social norms can perpetuate depressed vaccine coverage during a vaccine scare well beyond the time when the population's baseline vaccine risk perception returns to pre-scare levels. Social norms can strongly suppress vaccine uptake despite frequent outbreaks, as observed in some small communities. Significant portions of the parameter space also exhibit bistability, meaning long-term outcomes depend on the initial conditions. Depending on the context, social norms can either support or hinder immunization goals.

  12. SPLOSH II: A dynamics programme for nuclear - thermal - hydrodynamic behaviour of water-cooled reactors

    International Nuclear Information System (INIS)

    Moxon, D.

    1966-01-01

    A dynamics code is described that solves the two-group neutron diffusion equations simultaneously with the thermal and the hydraulic equations for an average channel of a water-cooled reactor. Other reactor channels can be represented as 'slaves', which have no feedback to the average channel. The fission power at any axial station in a slave channel is related to that in the average by prescribed time-dependent factors, and the hydraulic flow is determined from pressure-drop requirements dictated by the performance of the average channel. A finite difference model of the fuel element and can represents the behaviour of the fuel temperatures and surface heat flux. The representation of the hydraulic circuit has been made sufficiently general that the code is applicable to B.W.R., P.W.R. and pressure tube reactor designs. The code can be used to study transients resulting from imposed time variations in coolant flow, inlet enthalpy, system pressure, electrical torque supplied to the circulating pumps, (or alternatively, the angular velocity of the pump rotors,) moderator height, frictional resistances simulating blockages and control rod and fuel element insertions. The harmonic response can be obtained by injecting sinusoidal time variations until the starting transient has been damped out. Output includes axial distributions of the neutron fluxes, heat flux, coolant density and temperature, burn-but margin, and the fuel and can temperatures in both the average and the slave channels. The code was originally written in FORTRAN II for use on the IBM 7090. Computing times vary greatly with the problem and the desired accuracy but experience has shown that a computing time which is slower than real time by a factor thirty is adequate for a wide range of cases. The code has recently been converted to S2 and EGTRAN for use on the IBM 7030 and the English Electric Leo Marconi KDF 9 computers. (author)

  13. Enriching practice of dialectic behaviour therapy with the dynamic maturational model of attachment and adaptation.

    Science.gov (United States)

    Wilkinson, Simon R

    2016-01-01

    The major challenge for a clinician is integration of the wisdom available in the wide range of therapeutic paradigms available. I have found the principles guiding dialectic behaviour therapy (DBT; see Miller, Rathus, & Linehan, 2007, for applying DBT to adolescents) extremely useful in my practice running a general adolescent unit; similarly, the understanding of the different information processing and learning principles associated with each of the Type A and C attachment strategies, as understood in dynamic maturational model (DMM), has guided me through the dark corners of treatment. Specifically, how does DMM inform practice of DBT? As a 'DBTer' might say, 'Where is the wisdom in both points of view?' Nevertheless, DMM is not primarily about treatment. It concerns how different ways of adapting to developmental contingencies bias perceptual propensities, and hence the information available for reflective brain function. Recognition of these twists to knowing what is going on can then be used to inform a variety of therapeutic approaches. The purpose of this article is to look for the signposts in DBT and DMM which together help navigate the comprehensive approach necessary in complicated therapy. In the process, hopefully some more general principles for addressing discomfited adolescents arise for informing future practice. Although many steer shy of using personality disorder diagnoses for adolescents, clinicians are nevertheless addressing, directly or indirectly, the personality development of all adolescents in treatment, regardless of their classical axis I diagnoses, including both those with developing emotional instability and a group of avoidant over-controlled adolescents, which in Norway is growing in prominence. © The Author(s) 2014.

  14. Indirect learning control for nonlinear dynamical systems

    Science.gov (United States)

    Ryu, Yeong Soon; Longman, Richard W.

    1993-01-01

    In a previous paper, learning control algorithms were developed based on adaptive control ideas for linear time variant systems. The learning control methods were shown to have certain advantages over their adaptive control counterparts, such as the ability to produce zero tracking error in time varying systems, and the ability to eliminate repetitive disturbances. In recent years, certain adaptive control algorithms have been developed for multi-body dynamic systems such as robots, with global guaranteed convergence to zero tracking error for the nonlinear system euations. In this paper we study the relationship between such adaptive control methods designed for this specific class of nonlinear systems, and the learning control problem for such systems, seeking to converge to zero tracking error in following a specific command repeatedly, starting from the same initial conditions each time. The extension of these methods from the adaptive control problem to the learning control problem is seen to be trivial. The advantages and disadvantages of using learning control based on such adaptive control concepts for nonlinear systems, and the use of other currently available learning control algorithms are discussed.

  15. Function of dynamic models in systems biology: linking structure to behaviour.

    Science.gov (United States)

    Knüpfer, Christian; Beckstein, Clemens

    2013-10-08

    Dynamic models in Systems Biology are used in computational simulation experiments for addressing biological questions. The complexity of the modelled biological systems and the growing number and size of the models calls for computer support for modelling and simulation in Systems Biology. This computer support has to be based on formal representations of relevant knowledge fragments. In this paper we describe different functional aspects of dynamic models. This description is conceptually embedded in our "meaning facets" framework which systematises the interpretation of dynamic models in structural, functional and behavioural facets. Here we focus on how function links the structure and the behaviour of a model. Models play a specific role (teleological function) in the scientific process of finding explanations for dynamic phenomena. In order to fulfil this role a model has to be used in simulation experiments (pragmatical function). A simulation experiment always refers to a specific situation and a state of the model and the modelled system (conditional function). We claim that the function of dynamic models refers to both the simulation experiment executed by software (intrinsic function) and the biological experiment which produces the phenomena under investigation (extrinsic function). We use the presented conceptual framework for the function of dynamic models to review formal accounts for functional aspects of models in Systems Biology, such as checklists, ontologies, and formal languages. Furthermore, we identify missing formal accounts for some of the functional aspects. In order to fill one of these gaps we propose an ontology for the teleological function of models. We have thoroughly analysed the role and use of models in Systems Biology. The resulting conceptual framework for the function of models is an important first step towards a comprehensive formal representation of the functional knowledge involved in the modelling and simulation process

  16. Youth sexual behaviour in a boomtown: implications for the control of sexually transmitted infections.

    Science.gov (United States)

    Goldenberg, S; Shoveller, J; Ostry, A; Koehoorn, M

    2008-06-01

    Northeastern British Columbia, Canada, is undergoing rapid in-migration of young, primarily male, workers in response to the "boom" in the oil/gas industries. Chlamydia rates in the region exceed the provincial average by 32% (294.6 cases per 100 000 persons compared with 213.3). Evidence indicates that sociocultural and structural determinants of young people's sexual health are key to consider in the design of interventions. To investigate how sociocultural and structural features related to the oil/gas boom are perceived to affect the sexual behaviour of youth in a Northeastern "boomtown". The study included ethnographic fieldwork (8 weeks) and in-depth interviews with 25 youth (ages 15-25 years) and 14 health/social service providers. Participants identified four main ways in which the sociocultural and structural conditions created by the boom affect sexual behaviours, fuelling the spread of sexually transmitted infections (STIs): mobility of oil/gas workers; binge partying; high levels of disposable income and gendered power dynamics. The sociocultural and structural conditions that are fostered by a resource-extraction boom appear to exacerbate sexual health inequalities among youths who live and work in these rapidly urbanising, remote locales. To meet the needs of this population, we recommend STI prevention and testing service delivery models that incorporate STI testing outreach to oil/gas workers and condom distribution. Global, national and local STI control efforts should consider the realities and needs of similar subpopulations of young people.

  17. Coupling-induced cooperative behaviour in dynamic ferromagnetic cores in the presence of a noise floor

    International Nuclear Information System (INIS)

    Bulsara, Adi R.; Lindner, John F.; In, Visarath; Kho, Andy; Baglio, Salvatore; Sacco, Vincenzo; Ando, Bruno; Longhini, Patrick; Palacios, Antonio; Rappel, Wouter-Jan

    2006-01-01

    Recently, we have shown the emergence of oscillations in overdamped undriven nonlinear dynamic systems subject to carefully crafted coupling schemes and operating conditions. Here, we summarize experimental results obtained on a system of N=3 coupled ferromagnetic cores, the underpinning of a 'coupled-core fluxgate magnetometer' (CCFM); the oscillatory behaviour is triggered when the coupling constant exceeds a threshold value (bifurcation point), and the oscillation frequency exhibits a characteristic scaling behaviour with the 'separation' of the coupling constant from its threshold value, as well as with an external target DC magnetic flux signal. The oscillations, which can be induced at frequencies ranging from a few Hz to high-kHz, afford a new detection scheme for weak target magnetic signals. We also present the first (numerical) results on the effects of a (Gaussian, exponentially correlated) noise floor on the spectral properties of the system response

  18. Coupling-induced cooperative behaviour in dynamic ferromagnetic cores in the presence of a noise floor

    Energy Technology Data Exchange (ETDEWEB)

    Bulsara, Adi R. [Space and Naval Warfare Systems Center San Diego, Code 2363, 53560 Hull Street, San Diego, CA 92152-5001 (United States)]. E-mail: bulsara@spawar.navy.mil; Lindner, John F. [Physics Department, College of Wooster, Wooster, OH 44691 (United States); In, Visarath [Space and Naval Warfare Systems Center San Diego, Code 2363, 53560 Hull Street, San Diego, CA 92152-5001 (United States); Kho, Andy [Space and Naval Warfare Systems Center San Diego, Code 2363, 53560 Hull Street, San Diego, CA 92152-5001 (United States); Baglio, Salvatore [Dipartimento di Ingegneria Elettrica Elettronica e dei Sistemi, Universita degli Studi di Catania, Viale A. Doria 6, 95125 Catania (Italy); Sacco, Vincenzo [Dipartimento di Ingegneria Elettrica Elettronica e dei Sistemi, Universita degli Studi di Catania, Viale A. Doria 6, 95125 Catania (Italy); Ando, Bruno [Dipartimento di Ingegneria Elettrica Elettronica e dei Sistemi, Universita degli Studi di Catania, Viale A. Doria 6, 95125 Catania (Italy); Longhini, Patrick [Nonlinear Dynamics Group, Department of Mathematics, San Diego State University, San Diego, CA 92182 (United States); Palacios, Antonio [Nonlinear Dynamics Group, Department of Mathematics, San Diego State University, San Diego, CA 92182 (United States); Rappel, Wouter-Jan [Physics Department, University of California at San Diego, La Jolla, CA 929093 (United States)

    2006-04-17

    Recently, we have shown the emergence of oscillations in overdamped undriven nonlinear dynamic systems subject to carefully crafted coupling schemes and operating conditions. Here, we summarize experimental results obtained on a system of N=3 coupled ferromagnetic cores, the underpinning of a 'coupled-core fluxgate magnetometer' (CCFM); the oscillatory behaviour is triggered when the coupling constant exceeds a threshold value (bifurcation point), and the oscillation frequency exhibits a characteristic scaling behaviour with the 'separation' of the coupling constant from its threshold value, as well as with an external target DC magnetic flux signal. The oscillations, which can be induced at frequencies ranging from a few Hz to high-kHz, afford a new detection scheme for weak target magnetic signals. We also present the first (numerical) results on the effects of a (Gaussian, exponentially correlated) noise floor on the spectral properties of the system response.

  19. On the oscillatory dynamical behaviour of epidemic spreading in fractal media

    International Nuclear Information System (INIS)

    Bab, M A; Albano, E V

    2008-01-01

    We present numerical evidence that dynamical physical processes that develop a time-dependent characteristic length, and take place in fractal media exhibiting spatial discrete scale invariance (DSI) with fundamental scaling ratio b, may become coupled to the topology of the fractal leading to the observation of time DSI. The hallmark of time DSI is the observation of a log-periodic modulation of the dynamic or kinetic observables, which is characterized by a well-defined fundamental time scaling ratio (τ). Both fundamental scaling ratios are linked according to b = τ 1/z , where z is the dynamic exponent characteristic of the physical process. Specifically, we have studied the epidemic behaviour of the contact process (CP) in Sierpinski Carpets. The CP exhibits second-order irreversible phase transitions between an active regime and an absorbing state where the system is trapped without any escape possibility. We observed that relevant dynamic observables, such as the number of active sites, the survival probability of the epidemics and the mean square displacement of the epidemic from the origin (R 2 (t)), exhibit log-periodic modulations. By fitting the data we evaluate the fundamental time scaling ratio for various fractals and the corresponding dynamic exponents. Since, at criticality, one has that R 2 (t) ∼ t 2/z , an independent estimation of the dynamic exponent can be performed, in excellent agreement with results obtained by using the conjectured relationship for the fundamental scaling ratios b and τ

  20. On the oscillatory dynamical behaviour of epidemic spreading in fractal media

    Energy Technology Data Exchange (ETDEWEB)

    Bab, M A; Albano, E V [Instituto de Investigaciones FisicoquImicas Teoricas y Aplicadas (INIFTA), Facultad de Ciencias Exactas, UNLP, CONICET, Casilla de Correo 16, Sucursal 4 (1900) La Plata (Argentina)

    2008-02-01

    We present numerical evidence that dynamical physical processes that develop a time-dependent characteristic length, and take place in fractal media exhibiting spatial discrete scale invariance (DSI) with fundamental scaling ratio b, may become coupled to the topology of the fractal leading to the observation of time DSI. The hallmark of time DSI is the observation of a log-periodic modulation of the dynamic or kinetic observables, which is characterized by a well-defined fundamental time scaling ratio ({tau}). Both fundamental scaling ratios are linked according to b = {tau}{sup 1/z}, where z is the dynamic exponent characteristic of the physical process. Specifically, we have studied the epidemic behaviour of the contact process (CP) in Sierpinski Carpets. The CP exhibits second-order irreversible phase transitions between an active regime and an absorbing state where the system is trapped without any escape possibility. We observed that relevant dynamic observables, such as the number of active sites, the survival probability of the epidemics and the mean square displacement of the epidemic from the origin (R{sup 2}(t)), exhibit log-periodic modulations. By fitting the data we evaluate the fundamental time scaling ratio for various fractals and the corresponding dynamic exponents. Since, at criticality, one has that R{sup 2}(t) {approx} t{sup 2/z}, an independent estimation of the dynamic exponent can be performed, in excellent agreement with results obtained by using the conjectured relationship for the fundamental scaling ratios b and {tau}.

  1. CYCLIC PLASTIC BEHAVIOUR OF UFG COPPER UNDER CONTROLLED STRESS AND STRAIN LOADING

    Directory of Open Access Journals (Sweden)

    Lucie Navrátilová

    2012-01-01

    Full Text Available The influence of stress- and strain-controlled loading on microstructure and cyclic plastic behaviour of ultrafine-grained copper prepared by equal channel angular pressing was examined. The stability of microstructure is a characteristic feature for stress-controlled test whereas grain coarsening and development of bimodal structure was observed after plastic strain-controlled tests. An attempt to explain the observed behaviour was made.

  2. Long-term behaviour of timber structures in torrent control

    Science.gov (United States)

    Rickli, Christian; Graf, Frank

    2014-05-01

    Timber is widely used for protection measures in torrent control. However, life span of woody constructions such as timber check dams is limited due to fungal decay. However, only sparse scientific information is available on the long-term behaviour of timber structures and the colonisation with decay fungi. Related to this, in practice a controversial discussion has been going on if either Norway Spruce (Picea abies) or Silver Fir (Abies alba) is more enduring and if bark removal increases resistance against fungal decay. In order to going into this matter a series of 15 timber check dams built in 1996 has been monitored. The constructions were alternatively realised with Norway Spruce and Silver Fir, half of them each with remaining and removed bark, respectively. The scientific investigations included the documentation of colonisation with rot fungi and the identification of decayed zones with a simple practical approach as well as based on drilling resistance. Colonisation by decay fungi started three years after construction (e.g. Gloeophyllum sepiarium), detecting two years later first parts with reduced wood resistance. Sixteen years after construction decay was found on all check dams but two. Wood quality was markedly better in watered sections compared to the occasionally dry lateral abutment sections. Taking the whole check dams into consideration, slightly more decay was detected in Norway Spruce compared to logs in Silver Fir and both the practical approach and the drilling resistance measurement yielded in more defects on logs without bark. However, due to limited number of replications and fungal data, it was not possible to statistically verify these results. Statistical analysis was restricted to the drilling resistance data and fruit-bodies of decay fungi of the uppermost log of each check dam. Based on this limited analysis significant differences in the effect on the drilling resistance were found for watered sections and lateral abutments

  3. A new experimental setup to characterize the dynamic mechanical behaviour of ballistic yarns

    International Nuclear Information System (INIS)

    Chevalier, C; Kerisit, C; Faderl, N; Klavzar, A; Boussu, F; Coutellier, D

    2016-01-01

    Fabrics have been widely used as part of ballistic protections since the 1970s and the development of new ballistic solutions made from fabrics need numerical simulations, in order to predict the performance of the ballistic protection. The performances and the induced mechanisms in ballistic fabrics during an impact depend on the weaving parameters and also on the inner parameters of the yarns used inside these structures. Thus, knowing the dynamic behaviour of yarn is essential to determine the ballistic behaviour of fabrics during an impact. Two major experimental devices exist and are used to test ballistic yarns in a dynamic uniaxial tension. The first one corresponds to the Split Hopkinson Tensile Bars device, which is commonly used to characterize the mechanical properties of materials in uniaxial tension and under high loading. The second one is the transversal impact device. The real conditions of ballistic impact can be realized with this device. Then, this paper deals with a new experimental setup developed in our laboratory and called the ‘tensile impact test for yarn’ (TITY) device. With this device, specific absorbed energy measurements of para-aramid yarns (336 Tex, Twaron ™ , 1000 filaments) have been carried out and revealed that static and dynamic properties of para-aramid are different. (paper)

  4. Molecular dynamics simulations of a flexible polyethylene: a protein-like behaviour in a water solvent

    International Nuclear Information System (INIS)

    Kretov, D.A.; Kholmurodov, Kh.T.

    2005-01-01

    We used molecular dynamics (MD) simulations to study the density and the temperature behaviour of a flexible polyethylene (PE) subjected to various heating conditions and to investigate the PE chain conformational changes in a water solvent. First, we have considered the influence of the heating process on the final state of the polymeric system and the sensitivity of its thermodynamic characteristics (density, energy, etc.) for different heating regimes. For this purpose three different simulations were performed: fast, moderate, and slow heating. Second, we have investigated the PE chain conformational dynamics in water solvent for various simulation conditions and various configurations of the environment. From the obtained results we have got the pictures of the PE dynamical motions in water. We have observed a protein-like behaviour of the PE chain, like that of the DNA and the proteins in water, and have also estimated the rates of the conformational changes. For the MD simulations we used the optimized general-purpose DL P OLY code and the generic DREIDING force field. The MD simulations were performed on the parallel computers and special-purpose MDGRAPE-2 machine

  5. Strategic energy planning: Modelling and simulating energy market behaviours using system thinking and systems dynamics principles

    International Nuclear Information System (INIS)

    Papageorgiou, George Nathaniel

    2005-01-01

    In the face of limited energy reserves and the global warming phenomenon, Europe is undergoing a transition from rapidly depleting fossil fuels to renewable unconventional energy sources. During this transition period, energy shortfalls will occur and energy prices will be increasing in an oscillating manner. As a result of the turbulence and dynamicity that will accompany the transition period, energy analysts need new appropriate methods, techniques and tools in order to develop forecasts for the behaviour of energy markets, which would assist in the long term strategic energy planning and policy analysis. This paper reviews energy market behaviour as related to policy formation, and from a dynamic point of view through the use of ''systems thinking'' and ''system dynamics'' principles, provides a framework for modelling the energy production and consumption process in relation to their environment. Thereby, effective energy planning can be developed via computerised simulation using policy experimentation. In a demonstration model depicted in this paper, it is shown that disasters due to attractive policies can be avoided by using simple computer simulation. (Author)

  6. Success Stories in Control: Nonlinear Dynamic Inversion Control

    Science.gov (United States)

    Bosworth, John T.

    2010-01-01

    NASA plays an important role in advancing the state of the art in flight control systems. In the case of Nonlinear Dynamic Inversion (NDI) NASA supported initial implementation of the theory in an aircraft and demonstration in a space vehicle. Dr. Dale Enns of Honeywell Aerospace Advanced Technology performed this work in cooperation with NASA and under NASA contract. Honeywell and Lockheed Martin were subsequently contracted by AFRL to create "Design Guidelines for Multivariable Control Theory". This foundational work directly contributed to the advancement of the technology and the credibility of the control law as a design option. As a result Honeywell collaborated with Lockheed Martin to produce a Nonlinear Dynamic Inversion controller for the X-35 and subsequently Lockheed Martin did the same for the production Lockheed Martin F-35 vehicle. The theory behind NDI is to use a systematic generalized approach to controlling a vehicle. Using general aircraft nonlinear equations of motion and onboard aerodynamic, mass properties, and engine models specific to the vehicle, a relationship between control effectors and desired aircraft motion can be formulated. Using this formulation a control combination is used that provides a predictable response to commanded motion. Control loops around this formulation shape the response as desired and provide robustness to modeling errors. Once the control law is designed it can be used on a similar class of vehicle with only an update to the vehicle specific onboard models.

  7. Exercise habit strength, planning and the theory of planned behaviour: an action control approach

    NARCIS (Netherlands)

    de Bruijn, G.-J.

    2011-01-01

    Objectives Action control refers to the successful translation of intention into behaviour. The purpose of this study was to explore the potential usefulness of extending intention-exercise profiles with past exercise behaviour and exercise habit strength and the potential discriminative effect of

  8. Moment-to-moment dynamics of ADHD behaviour in South African children

    Directory of Open Access Journals (Sweden)

    Meyer Anneke

    2006-03-01

    Full Text Available Abstract Background The behaviour of children with Attention-Deficit/Hyperactivity Disorder is characterized by low predictability of responding. Low behavioural predictability is one way of operationalizing intra-individual ADHD-related variability. ADHD-related variability may be caused by inefficient behavioural selection mechanisms linked to reinforcement and extinction, as suggested by the recently published dynamic developmental theory (DDT of ADHD. DDT argues that ADHD is a basic neurobehavioural disorder, caused by dysfunctioning dopamine systems. For establishing ADHD as a neurobehavioural disorder, findings from studies conducted in Western countries should be replicated in other cultural populations. The present study replicated the study conducted in Norway, with children from the Limpopo province in the Republic of South Africa. Methods Boys and girls, aged 6–9 yr, from seven ethnic groups participated. Scores by teachers on the Disruptive Behavior Disorders rating scale defined participation in either ADHD-hyperactive/impulsive (-HI, ADHD-predominantly inattentive (-PI, or ADHD-combined (-C groups. Children below the 86th percentile were matched on gender and age and comprised the non-ADHD group. The children completed a computerized game-like task where mouse clicks on one of two squares on the screen resulted in delivery of a reinforcer according to a variable interval schedule of reinforcement. Reinforcers were cartoon pictures presented on the screen together with a sound. Predictability of response location and timing were measured in terms of explained variance. Results Overall, the results replicated findings from Norway. Specifically, the ADHD-C group showed significantly lower predictability of responding than the non-ADHD group, while the ADHD-HI and the ADHD-PI groups were in-between. In accordance with the previous study, response location, but not response timing, was a sensitive behavioural measure. There were no

  9. Occupant behaviour and control of indoor environment in Danish dwellings

    DEFF Research Database (Denmark)

    Andersen, Rune Vinther; Toftum, Jørn; Olesen, Bjarne W.

    2007-01-01

    Repeated surveys on occupant behaviour and indoor climate were carried out in Danish dwellings from September to October 2006 and again from February to March 2007. The summer survey comprised 933 respondents and the winter survey 636 respondents. The surveys were carried out by sending 5000...

  10. Adolescent externalizing behaviour, psychological control, and peer rejection: Transactional links and dopaminergic moderation.

    Science.gov (United States)

    Janssens, Annelies; Van Den Noortgate, Wim; Goossens, Luc; Verschueren, Karine; Colpin, Hilde; Claes, Stephan; Van Heel, Martijn; Van Leeuwen, Karla

    2017-09-01

    This study investigated (1) reciprocal links among parental psychological control, peer rejection, and adolescent externalizing (aggressive and rule-breaking behaviour), and (2) the moderating effect of an adolescent genetic factor (biologically informed polygenic score for dopamine signalling). Three-year longitudinal data from 1,116 adolescents (51% boys; M age = 13.79) and their parents included psychological measures (adolescent-reported psychological control, peer-reported rejection, and parent-reported aggressive and rule-breaking behaviour). Cross-lagged analyses showed bidirectional effects between psychological control and both aggressive and rule-breaking behaviour and a unidirectional effect of peer rejection on both forms of problem behaviour over time. Multigroup structural equation modelling revealed genetic moderation only for rule-breaking behaviour: for adolescents with intermediate levels of dopamine signalling significant environmental effects were present, whereas adolescent effects of rule-breaking behaviour on psychological control were significant for adolescents with both intermediate and high profiles and effects on peer rejection only for adolescents with high dopamine profiles. Statement of contribution What is already known on this subject? Parental psychological control is related to adolescent externalizing problems. Experiencing peer rejection reinforces aggressive and rule-breaking behaviour. Single-gene studies show that dopaminergic genes influence externalizing problems directly or in interaction with the environment. What does this study add? Parental psychological control and adolescent aggressive and rule-breaking behaviour exacerbate one another longitudinally. Longitudinal associations between peer rejection and both subtypes of externalizing behaviour are unidirectional. With a polygenic approach, dopaminergic moderation is present for rule-breaking behaviour only. © 2017 The British Psychological Society.

  11. Numerical Investigations of Dynamic Stall Control

    Directory of Open Access Journals (Sweden)

    Florin FRUNZULICA

    2014-04-01

    Full Text Available In this paper we investigated numerically the dynamic stall phenomenon and the possibilities to control it, with application to vertical axis wind turbines (for urban users. The Phenomenon appear at low tip speed ratio (TSR<4 and it has a great impact on structural integrity of the wind turbine and power performances. For this reason we performed a computational study of dynamic stall around NACA 0012 airfoil in pitching motion at relative low Reynolds number (105. Also, we performed the same analysis for four flow control methods: two passive (Gurney flap and slot and two active (blowing jet on the rounded trailing edge and synthetic jet periodically activated. The Results are compared to those of an existing experimental case test.

  12. Energy Management Dynamic Control Topology In MANET

    Science.gov (United States)

    Madhusudan, G.; Kumar, TNR

    2017-08-01

    Topology management via per-node transmission power adjustment has been shown effective in extending network lifetime. The existing algorithms constructs static topologies which fail to take the residual energy of network nodes, and cannot balance energy consumption efficiently. To address this problem, a Light Weighted Distributed Topology Control algorithm EMDCT(Energy Management Dynamic Control Topology ) is proposed in this paper. Based on the link metric of the network, both the energy consumption rate level and residual energy levels at the two end nodes are considered. EMDCT generates a Dynamic Topology that changes with the variation of node energy without the aid of location information, each node determines its transmission power according to local network information, which reduces the overhead complexity of EMDCT greatly. The experiment results show that EMDCT preserves network connectivity and manitains minimum-cost property of the network also it can extend network lifetime more remarkably.

  13. The TNO Vehicle Dynamics Database (VDD): a tool for comparision of vehicle dynamics behaviour

    NARCIS (Netherlands)

    Kleuskens, R.J.A.

    1996-01-01

    TNO has started a database containing data of vehicle dynamics properties of passenger cars, based on the results of eight objective ISO driving tests. From this database, car manufacturers and their suppliers can get the required information for design and marketing purposes in a fast and

  14. Nonuniversal critical behaviour in a model for charge density wave dynamics

    International Nuclear Information System (INIS)

    Ritala, R.K.; Hertz, J.A.

    1986-02-01

    We have studied short range fluctuations around the infinite-range model of charge density wave (CDW) dynamics. We find that the inhomogeneity of the local field, which is neglected in the infinite-range approximation has a dramatic effect on the transition. In the Bethe approximation the critical behaviour is nonuniversal. In particular, the current exponent is ζ = 3/2 log(z-1)/[log(z)]+log(1+f/J)], where z is the number of neighbors, f the pinning strength, and J the elastic coupling. (orig.)

  15. Extrapolation of dynamic load behaviour on hydroelectric turbine blades with cyclostationary modelling

    Science.gov (United States)

    Poirier, Marc; Gagnon, Martin; Tahan, Antoine; Coutu, André; Chamberland-lauzon, Joël

    2017-01-01

    In this paper, we present the application of cyclostationary modelling for the extrapolation of short stationary load strain samples measured in situ on hydraulic turbine blades. Long periods of measurements allow for a wide range of fluctuations representative of long-term reality to be considered. However, sampling over short periods limits the dynamic strain fluctuations available for analysis. The purpose of the technique presented here is therefore to generate a representative signal containing proper long term characteristics and expected spectrum starting with a much shorter signal period. The final objective is to obtain a strain history that can be used to estimate long-term fatigue behaviour of hydroelectric turbine runners.

  16. The Matrix exponential, Dynamic Systems and Control

    DEFF Research Database (Denmark)

    Poulsen, Niels Kjølstad

    The matrix exponential can be found in various connections in analysis and control of dynamic systems. In this short note we are going to list a few examples. The matrix exponential usably pops up in connection to the sampling process, whatever it is in a deterministic or a stochastic setting...... or it is a tool for determining a Gramian matrix. This note is intended to be used in connection to the teaching post the course in Stochastic Adaptive Control (02421) given at Informatics and Mathematical Modelling (IMM), The Technical University of Denmark. This work is a result of a study of the litterature....

  17. Neuromechanical tuning of nonlinear postural control dynamics

    Science.gov (United States)

    Ting, Lena H.; van Antwerp, Keith W.; Scrivens, Jevin E.; McKay, J. Lucas; Welch, Torrence D. J.; Bingham, Jeffrey T.; DeWeerth, Stephen P.

    2009-06-01

    Postural control may be an ideal physiological motor task for elucidating general questions about the organization, diversity, flexibility, and variability of biological motor behaviors using nonlinear dynamical analysis techniques. Rather than presenting "problems" to the nervous system, the redundancy of biological systems and variability in their behaviors may actually be exploited to allow for the flexible achievement of multiple and concurrent task-level goals associated with movement. Such variability may reflect the constant "tuning" of neuromechanical elements and their interactions for movement control. The problem faced by researchers is that there is no one-to-one mapping between the task goal and the coordination of the underlying elements. We review recent and ongoing research in postural control with the goal of identifying common mechanisms underlying variability in postural control, coordination of multiple postural strategies, and transitions between them. We present a delayed-feedback model used to characterize the variability observed in muscle coordination patterns during postural responses to perturbation. We emphasize the significance of delays in physiological postural systems, requiring the modulation and coordination of both the instantaneous, "passive" response to perturbations as well as the delayed, "active" responses to perturbations. The challenge for future research lies in understanding the mechanisms and principles underlying neuromechanical tuning of and transitions between the diversity of postural behaviors. Here we describe some of our recent and ongoing studies aimed at understanding variability in postural control using physical robotic systems, human experiments, dimensional analysis, and computational models that could be enhanced from a nonlinear dynamics approach.

  18. Chaos control applied to heart rhythm dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Borem Ferreira, Bianca, E-mail: biaborem@gmail.com [Universidade Federal do Rio de Janeiro, COPPE, Department of Mechanical Engineering, P.O. Box 68.503, 21.941.972 Rio de Janeiro, RJ (Brazil); Souza de Paula, Aline, E-mail: alinedepaula@unb.br [Universidade de Brasi' lia, Department of Mechanical Engineering, 70.910.900 Brasilia, DF (Brazil); Amorim Savi, Marcelo, E-mail: savi@mecanica.ufrj.br [Universidade Federal do Rio de Janeiro, COPPE, Department of Mechanical Engineering, P.O. Box 68.503, 21.941.972 Rio de Janeiro, RJ (Brazil)

    2011-08-15

    Highlights: > A natural cardiac pacemaker is modeled by a modified Van der Pol oscillator. > Responses related to normal and chaotic, pathological functioning of the heart are investigated. > Chaos control methods are applied to avoid pathological behaviors of heart dynamics. > Different approaches are treated: stabilization of unstable periodic orbits and chaos suppression. - Abstract: The dynamics of cardiovascular rhythms have been widely studied due to the key aspects of the heart in the physiology of living beings. Cardiac rhythms can be either periodic or chaotic, being respectively related to normal and pathological physiological functioning. In this regard, chaos control methods may be useful to promote the stabilization of unstable periodic orbits using small perturbations. In this article, the extended time-delayed feedback control method is applied to a natural cardiac pacemaker described by a mathematical model. The model consists of a modified Van der Pol equation that reproduces the behavior of this pacemaker. Results show the ability of the chaos control strategy to control the system response performing either the stabilization of unstable periodic orbits or the suppression of chaotic response, avoiding behaviors associated with critical cardiac pathologies.

  19. Dynamic control of quadruped robot with hierarchical control structure

    International Nuclear Information System (INIS)

    Wang, Yu-Zhang; Furusho, Junji; Okajima, Yosuke.

    1988-01-01

    For moving on irregular terrain, such as the inside of a nuclear power plant and outer space, it is generally recognized that the multilegged walking robot is suitable. This paper proposes a hierarchical control structure for the dynamic control of quadruped walking robots. For this purpose, we present a reduced order model which can approximate the original higher order model very well. Since this reduced order model does not require much computational time, it can be used in the real-time control of a quadruped walking robot. A hierarchical control experiment is shown in which the optimal control algorithm using a reduced order model is calculated by one microprocessor, and the other control algorithm is calculated by another microprocessor. (author)

  20. Dynamic modeling and control of CFSTF

    International Nuclear Information System (INIS)

    Danesh, Y.; Jalali Farahani, F.

    2001-01-01

    This paper deals with the modeling and control of a continuous-flow fermentation process for the production of alcohol: The dynamic behavior of ferment ors has been developed from mass balance and leads to nonlinear differential equations. Based on the proposed model, two computer algorithms are provided to control output alcohol concentration at the desired value by input flow rate manipulation. The first algorithm is based on a conventional Proportional-Integral-Derivative, in which its parameters are determined in a trial and error procedure. The second algorithm is based on optimal controllers. In this way, the difference between output alcohol concentration and desired value is minimized by flow rate manipulation. Minimization (optimization) is done based on the MARQYARDT procedure. The advantages of this method over the conventional Proportional-Integral-Derivative controller are its higher speed and lack of overshoot

  1. Estimation and control of dynamical systems

    CERN Document Server

    Bensoussan, Alain

    2018-01-01

    This book provides a comprehensive presentation of classical and advanced topics in estimation and control of dynamical systems with an emphasis on stochastic control. Many aspects which are not easily found in a single text are provided, such as connections between control theory and mathematical finance, as well as differential games. The book is self-contained and prioritizes concepts rather than full rigor, targeting scientists who want to use control theory in their research in applied mathematics, engineering, economics, and management science. Examples and exercises are included throughout, which will be useful for PhD courses and graduate courses in general. Dr. Alain Bensoussan is Lars Magnus Ericsson Chair at UT Dallas and Director of the International Center for Decision and Risk Analysis which develops risk management research as it pertains to large-investment industrial projects that involve new technologies, applications and markets. He is also Chair Professor at City University Hong Kong.

  2. Chasing behaviour and optomotor following in free-flying male blowflies: flight performance and interactions of the underlying control systems

    Directory of Open Access Journals (Sweden)

    Christine Trischler

    2010-05-01

    Full Text Available The chasing behaviour of male blowflies after small targets belongs to the most rapid and virtuosic visually guided behaviours found in nature. Since in a structured environment any turn towards a target inevitably leads to a displacement of the entire retinal image in the opposite direction, it might evoke optomotor following responses counteracting the turn. To analyse potential interactions between the control systems underlying chasing behaviour and optomotor following, respectively, we performed behavioural experiments on male blowflies and examined the characteristics of the two flight control systems in isolation and in combination. Three findings are particularly striking. (i The characteristic saccadic flight and gaze style – a distinctive feature of blowfly cruising flights – is largely abandoned when the entire visual surroundings move around the fly; in this case flies tend to follow the moving pattern in a relatively continuous and smooth way. (ii When male flies engage in following a small target, they also employ a smooth pursuit strategy. (iii Although blowflies are reluctant to fly at high background velocities, the performance and dynamical characteristics of the chasing system are not much affected when the background moves in either the same or in the opposite direction as the target. Hence, the optomotor following response is largely suppressed by the chasing system and does not much impair chasing performance.

  3. Aircraft Landing and Attitude Control Using Dynamic Matrix Control

    Directory of Open Access Journals (Sweden)

    George Cristian Calugaru

    2017-06-01

    Full Text Available This paper proposes a method for an efficient control of the aircraft landing and attitude through Dynamic Matrix Control. The idea of MPC structures used in aircraft control has been well established during the last few years, but some aspects require further investigation. With this in mind, the paper proposes structures for aircraft landing and aircraft attitude control by using single DMC controllers for landing and respectively one DMC controller for each of the attitude axis (pitch attitude hold, bank angle hold and heading hold. The model used for analysis of the aircraft landing structure is based on the last phase of landing. Also, the model used to illustrate the attitude control is that of a pitch attitude hold system of a N250-100 aircraft. Simulations are performed for a variety of control and prediction horizons, taking into account the possibility of adding a weighting factor for the control actions. Apart from separate studies on step reference variations, for some use cases, a generic reference trajectory is provided as a control purpose of the system. Results show a better performance of the proposed method in terms of control surface transition and protection of the actuators involved and a better time response in stabilizing the aircraft attitude. Overall, the aspects shown ensure an improved aircraft attitude control and landing stabilization.

  4. Assessment of the Dynamic Behaviour of Saturated Soil Subjected to Cyclic Loading from Offshore Monopile Wind Turbine Foundations

    DEFF Research Database (Denmark)

    Damgaard, Mads; Bayat, Mehdi; Andersen, Lars Vabbersgaard

    2014-01-01

    The fatigue life of offshore wind turbines strongly depends on the dynamic behaviour of the structures including the underlying soil. To diminish dynamic amplification and avoid resonance, the eigenfrequency related to the lowest eigenmode of the wind turbine should not coalesce with excitation f...

  5. Modeling the effect of sedentary behaviour on the prevention of population obesity using the system dynamics approach

    Science.gov (United States)

    Abidin, Norhaslinda Zainal; Zaibidi, Nerda Zura; Zulkepli, Jafri Hj

    2015-10-01

    Obesity is a medical condition where an individual has an excessive amount of body fat. There are many factors contributing to obesity and one of them is the sedentary behaviour. Rapid development in industrialization and urbanization has brought changes to Malaysia's socioeconomic, especially the lifestyles of Malaysians. With this lifestyle transition, one of the impact is on weight and obesity. How does sedentary behaviour have an impact on the growth of Malaysian population's weight and obesity? What is the most effective sedentary behaviour preventing strategy to obesity? Is it through reduction in duration or frequency of sedentary behaviour? Thus, the aim of this paper is to design an intervention to analyse the effect of decreasing duration and frequency of sedentary behaviour on the population reversion trends of average weight (AW), average body mass index (ABMI), and prevalence of overweight and obesity (POVB). This study combines the different strands of sub-models comprised of nutrition, physical activity and body metabolism, and then synthesis these knowledge into a system dynamics of weight behaviour model, namely SIMULObese. Findings from this study revealed that Malaysian's adults spend a lot of time engaged in sedentary behaviour and this resulted in weight gain and obesity. Comparing between frequency and duration of sedentary behaviour, this study reported that reduced in duration or time spend in sedentary behaviour is a better preventing strategy to obesity compared to duration. As a summary, this study highlighted the importance of decreasing the frequency and duration of sedentary behaviour in developing guidelines to prevent obesity.

  6. Locus of control, hardiness, and emotional intelligence as predictors of waste prevention behaviours

    Directory of Open Access Journals (Sweden)

    Abdollahi, A.

    2015-07-01

    Full Text Available Given that waste generation is an economic and environmental problem for nations and governments, it is necessary that we advance our knowledge on the etiology of waste prevention behaviours. This study aimed to investigate about the relationships between the locus of control, hardiness, emotional intelligence, and waste prevention behaviours. Four hundred and forty participants (226 females and 214 males from Universiti Putra Malaysia completed a survey questionnaire. Structural Equation Modeling (SEM estimated that individuals who were high in emotional intelligence and hardiness showed better waste prevention behaviours as well as those individuals with internal locus of control. Also, the results showed that older students tend to have better waste prevention behaviours. These findings reinforce the importance of personality traits and emotional intelligence in waste prevention behaviours.

  7. The Relationship between Parental Control and High-Risk Internet Behaviours in Adolescence

    Directory of Open Access Journals (Sweden)

    David Álvarez-García

    2018-06-01

    Full Text Available One of the main predictors of being a victim of cyber-aggression is engaging in high-risk behaviours on the internet. The main objective of this research is to analyse the relationship between two types of parental control (restriction and supervision and engagement in high-risk internet behaviours during adolescence. To that end, and as a secondary objective, we designed and validated the High-risk Internet Behaviours Questionnaire for adolescents, used in this study. We analysed the responses of 946 adolescents aged between 12 and 18 to the High-risk Internet Behaviours Questionnaire and the Questionnaire on Parental Control of Internet Use in Adolescence. The results show that the questionnaire has appropriate metrics of reliability and validity, and show the existence of a statistically significant negative relationship, albeit small, between supervision and engaging in high-risk internet behaviours. We discuss the practical implications of these results.

  8. Model-based dynamic control and optimization of gas networks

    Energy Technology Data Exchange (ETDEWEB)

    Hofsten, Kai

    2001-07-01

    by a structured sequential quadratic programming algorithm of Newton type. Each open loop problem is specified using a nonlinear prediction model. For each iteration of the quadratic programming procedure, a linear time variant prediction model is formulated. The suggested controller also handles time varying source capacity. Potential problems such as infeasibility and the security of the supply when facing a change in the status of the infrastructure of the transmission system under a transient customer load are treated. Comments on the infeasibility due to errors such as load forecast error, model error and state estimation error are also discussed. A simplified nonlinear model called the creep flow model is used to describe the fluid dynamics inside a natural gas transmission line. Different assumptions and reformulations of this model yield the different control, simulation and optimization models used in this thesis. The control of a single gas transmission line is investigated using linear model predictive control based on instant linearization of the nonlinear model. Model predictive control using a bi quadratic optimization model formulated from the creep flow model is also investigated. A distributed parameter control model of the gas dynamics for a transmission line is formulated. An analytic solution of this model is given with both Neuman boundary conditions and distributed supplies and loads. A transfer function model is developed expressing the dynamics between the defined output and the control and disturbance inputs of the transmission line. Based on the qualitative behaviour observed from the step responses of the solutions of the distributed parameter model formulated in this thesis, simplified transfer function models were developed. These control models expresses the dynamics of a natural gas transmission line with Neuman boundary control and load. Further, these models were used to design a control law, which is a combination of a Smith

  9. Achieving dynamic behaviour and thermal expansion in the organic solid state via co-crystallization.

    Science.gov (United States)

    Hutchins, Kristin M; Groeneman, Ryan H; Reinheimer, Eric W; Swenson, Dale C; MacGillivray, Leonard R

    2015-08-01

    Thermal expansion involves a response of a material to an external stimulus that typically involves an increase in a crystallographic axis (positive thermal expansion (PTE)), although shrinking with applied heat (negative thermal expansion (NTE)) is known in rarer cases. Here, we demonstrate a means to achieve dynamic molecular motion and thermal expansions in organic solids via co-crystallizations. One co-crystal component is known to exhibit dynamic behaviour in the solid state while the second, when varied systematically, affords co-crystals with linear thermal expansion coefficients that range from colossal to nearly zero. Two co-crystals exhibit rare NTE. We expect the approach to guide the design of molecular solids that enable predesigned motion related to thermal expansion processes.

  10. The behaviour of a vehicle’s suspension system on dynamic testing conditions

    Science.gov (United States)

    Mihon, L.; Lontiş, N.; Deac, S.

    2018-01-01

    The paper presents a car suspension’s behaviour on dynamic testing conditions through theoretical and mathematical simulation on specific model, on the single traction wheel, according to the real vehicle and by experiment on the test bench by reproducing the road’s geometry and vehicle’s speed and measuring the acceleration and damping response of the suspension system on that wheel. There are taking in consideration also the geometry and properties of the tyre-wheel model and physical wheel’s properties. The results are important due to the suspension’s model properties which allows to extend the theory and applications to the whole vehicle for improving the vehicle’s dynamics.

  11. Resetting dynamic behaviour of pipework systems; Recalage du comportement dynamique des reseaux de tuyauteries

    Energy Technology Data Exchange (ETDEWEB)

    Gaudin, M [Electricite de France (EDF), Direction des Etudes et Recherches, 92 - Clamart (France)

    1998-12-31

    Resetting models is applied to electricity generating plant pipework systems. A frequency approach to the problem is made in an original way thanks to the use of precise dynamic rigidity matrices. The method assumes two kinds of unknown: the usually processed mechanical characteristics (Young`s Modulus, density etc.) and new resetting parameters acting on the dynamic behaviour of unknown connections. As the latter have a very wide range of possible variation, they benefit from a change of variable which allows the assumptions formulated to be complied with. The minimized cost function is based on a error in load. The frequencies required for building it are automatically selected thanks to different tests on measurements. Minimization uses a sensitivity technique linked with a method of least standard squares. The method has been programmed in Fortran 90 within the CIRCUS code and tried out on various examples which were simulated and sound effects cases as well as an actual case. (author). 128 refs.

  12. Brittle versus ductile behaviour of nanotwinned copper: A molecular dynamics study

    International Nuclear Information System (INIS)

    Pei, Linqing; Lu, Cheng; Zhao, Xing; Zhang, Liang; Cheng, Kuiyu; Michal, Guillaume; Tieu, Kiet

    2015-01-01

    Nanotwinned copper (Cu) exhibits an unusual combination of ultra-high yield strength and high ductility. A brittle-to-ductile transition was previously experimentally observed in nanotwinned Cu despite Cu being an intrinsically ductile metal. However, the atomic mechanisms responsible for brittle fracture and ductile fracture in nanotwinned Cu are still not clear. In this study, molecular dynamics (MD) simulations at different temperatures have been performed to investigate the fracture behaviour of a nanotwinned Cu specimen with a single-edge-notched crack whose surface coincides with a twin boundary. Three temperature ranges are identified, indicative of distinct fracture regimes, under tensile straining perpendicular to the twin boundary. Below 1.1 K, the crack propagates in a brittle fashion. Between 2 K and 30 K a dynamic brittle-to-ductile transition is observed. Above 40 K the crack propagates in a ductile mode. A detailed analysis has been carried out to understand the atomic fracture mechanism in each fracture regime

  13. Resetting dynamic behaviour of pipework systems; Recalage du comportement dynamique des reseaux de tuyauteries

    Energy Technology Data Exchange (ETDEWEB)

    Gaudin, M. [Electricite de France (EDF), Direction des Etudes et Recherches, 92 - Clamart (France)

    1997-12-31

    Resetting models is applied to electricity generating plant pipework systems. A frequency approach to the problem is made in an original way thanks to the use of precise dynamic rigidity matrices. The method assumes two kinds of unknown: the usually processed mechanical characteristics (Young`s Modulus, density etc.) and new resetting parameters acting on the dynamic behaviour of unknown connections. As the latter have a very wide range of possible variation, they benefit from a change of variable which allows the assumptions formulated to be complied with. The minimized cost function is based on a error in load. The frequencies required for building it are automatically selected thanks to different tests on measurements. Minimization uses a sensitivity technique linked with a method of least standard squares. The method has been programmed in Fortran 90 within the CIRCUS code and tried out on various examples which were simulated and sound effects cases as well as an actual case. (author). 128 refs.

  14. Critical behaviour of the randomly stirred dynamical Potts model: novel universality class and effects of compressibility

    International Nuclear Information System (INIS)

    Antonov, N V; Kapustin, A S

    2012-01-01

    Critical behaviour of the dynamical Potts model, subjected to vivid turbulent mixing, is studied by means of the renormalization group. The advecting velocity field is modelled by Kraichnan’s rapid-change ensemble: Gaussian statistics with a given pair correlator 〈vv〉∝δ(t − t′) k −d−ξ , where k is the wave number, d is the dimension of space and 0 < ξ < 2 is an arbitrary exponent. The system exhibits different types of infrared scaling behaviour, associated with four infrared attractors of the renormalization group equations. In addition to the known asymptotic regimes (equilibrium Potts model and passive scalar field), the existence of a new, strongly non-equilibrium type of critical behaviour (universality class) is established, where the self-interaction of the order parameter and the turbulent mixing are equally important. The corresponding critical dimensions and the regions of stability for all the regimes are calculated in the leading order of the double expansion in ξ and ε = 6 − d. Special attention is paid to the effects of compressibility of the fluid, because they lead to interesting crossover phenomena. (paper)

  15. Modelling human behaviour in a bumper car ride using molecular dynamics tools: a student project

    Science.gov (United States)

    Buendía, Jorge J.; Lopez, Hector; Sanchis, Guillem; Pardo, Luis Carlos

    2017-05-01

    Amusement parks are excellent laboratories of physics, not only to check physical laws, but also to investigate if those physical laws might also be applied to human behaviour. A group of Physics Engineering students from Universitat Politècnica de Catalunya has investigated if human behaviour, when driving bumper cars, can be modelled using tools borrowed from the analysis of molecular dynamics simulations, such as the radial and angular distribution functions. After acquiring several clips and obtaining the coordinates of the cars, those magnitudes are computed and analysed. Additionally, an analogous hard disks system is simulated to compare its distribution functions to those obtained from the cars’ coordinates. Despite the clear difference between bumper cars and a hard disk-like particle system, the obtained distribution functions are very similar. This suggests that there is no important effect of the individuals in the collective behaviour of the system in terms of structure. The research, performed by the students, has been undertaken in the frame of a motivational project designed to approach the scientific method for university students named FISIDABO. This project offers both the logistical and technical support to undertake the experiments designed by students at the amusement park of Barcelona TIBIDABO and accompanies them all along the scientific process.

  16. The BOXES Methodology Black Box Dynamic Control

    CERN Document Server

    Russell, David W

    2012-01-01

    Robust control mechanisms customarily require knowledge of the system’s describing equations which may be of the high order differential type.  In order to produce these equations, mathematical models can often be derived and correlated with measured dynamic behavior.  There are two flaws in this approach one is the level of inexactness introduced by linearizations and the other when no model is apparent.  Several years ago a new genre of control systems came to light that are much less dependent on differential models such as fuzzy logic and genetic algorithms. Both of these soft computing solutions require quite considerable a priori system knowledge to create a control scheme and sometimes complicated training program before they can be implemented in a real world dynamic system. Michie and Chambers’ BOXES methodology created a black box system that was designed to control a mechanically unstable system with very little a priori system knowledge, linearization or approximation.  All the method need...

  17. Dynamic Parameter-Control Chaotic System.

    Science.gov (United States)

    Hua, Zhongyun; Zhou, Yicong

    2016-12-01

    This paper proposes a general framework of 1-D chaotic maps called the dynamic parameter-control chaotic system (DPCCS). It has a simple but effective structure that uses the outputs of a chaotic map (control map) to dynamically control the parameter of another chaotic map (seed map). Using any existing 1-D chaotic map as the control/seed map (or both), DPCCS is able to produce a huge number of new chaotic maps. Evaluations and comparisons show that chaotic maps generated by DPCCS are very sensitive to their initial states, and have wider chaotic ranges, better unpredictability and more complex chaotic behaviors than their seed maps. Using a chaotic map of DPCCS as an example, we provide a field-programmable gate array design of this chaotic map to show the simplicity of DPCCS in hardware implementation, and introduce a new pseudo-random number generator (PRNG) to investigate the applications of DPCCS. Analysis and testing results demonstrate the excellent randomness of the proposed PRNG.

  18. Simulation program for the dynamic behaviour of the primary system and moderators's circuit of the Atucha I Nuclear Power Plant

    International Nuclear Information System (INIS)

    Castano, Jorge; Gvirtzman, H.A.

    1981-01-01

    A model of digital computation is presented to simulate the primary system of heat transportation, moderator system and the associated systems for adjustment, regulation and control in the PHWR reactor at the Atucha-1 nuclear power plant. The model discusses in a concentrated way the different components and allows the study of the dynamical behaviour of the power plant facing disturbances with respect to a state of stationary regime. General considerations and description of the model are made. The method is described showing flow sheets, graphs and developing basic formulas, simulating a primary system, moderator and secondary system of the steam generator and the main system of regulation. Also an analysis of the results is made, for the case of disturbances which reduce or increase the power of the reactor by 10%. (V.B.) [es

  19. 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.

  20. Hygiene behaviour and hospitalized severe childhood diarrhoea: a case-control study.

    OpenAIRE

    Baltazar, J. C.; Tiglao, T. V.; Tempongko, S. B.

    1993-01-01

    The relationship between personal and domestic hygiene behaviour and hospitalized childhood diarrhoea was examined in a case-control study of 356 cases and 357 controls from low-income families in metropolitan Manila. Indices of hygiene behaviour were defined for overall cleanliness, kitchen hygiene, and living conditions. Only the indices for overall cleanliness and kitchen hygiene were significantly associated with diarrhoea. An increasing excess risk of hospitalization with severe diarrhoe...

  1. Obesity, Body Image, Depression, and Weight-control Behaviour Among Female University Students in Korea

    OpenAIRE

    Jun, Eun Mi; Choi, Seung Bae

    2014-01-01

    Background: Obesity has become epidemic worldwide and 31.0% of Korean adults are obese. Obesity is the main cause of chronic diseases, such as diabetes, hypertension, cardiac disease, and cancer. The purpose of the study was to examine obesity, body image, depression, and weight-control behaviour among Korean female university students and investigate the differences in body image, depression, and weight-control behaviour with respect to obesity. Methods: This study examined obesity, body ima...

  2. Role of graph architecture in controlling dynamical networks with applications to neural systems

    Science.gov (United States)

    Kim, Jason Z.; Soffer, Jonathan M.; Kahn, Ari E.; Vettel, Jean M.; Pasqualetti, Fabio; Bassett, Danielle S.

    2018-01-01

    Networked systems display complex patterns of interactions between components. In physical networks, these interactions often occur along structural connections that link components in a hard-wired connection topology, supporting a variety of system-wide dynamical behaviours such as synchronization. Although descriptions of these behaviours are important, they are only a first step towards understanding and harnessing the relationship between network topology and system behaviour. Here, we use linear network control theory to derive accurate closed-form expressions that relate the connectivity of a subset of structural connections (those linking driver nodes to non-driver nodes) to the minimum energy required to control networked systems. To illustrate the utility of the mathematics, we apply this approach to high-resolution connectomes recently reconstructed from Drosophila, mouse, and human brains. We use these principles to suggest an advantage of the human brain in supporting diverse network dynamics with small energetic costs while remaining robust to perturbations, and to perform clinically accessible targeted manipulation of the brain's control performance by removing single edges in the network. Generally, our results ground the expectation of a control system's behaviour in its network architecture, and directly inspire new directions in network analysis and design via distributed control.

  3. Wake flow control using a dynamically controlled wind turbine

    Science.gov (United States)

    Castillo, Ricardo; Wang, Yeqin; Pol, Suhas; Swift, Andy; Hussain, Fazle; Westergaard, Carsten; Texas Tech University Team

    2016-11-01

    A wind tunnel based "Hyper Accelerated Wind Farm Kinematic-Control Simulator" (HAWKS) is being built at Texas Tech University to emulate controlled wind turbine flow physics. The HAWKS model turbine has pitch, yaw and speed control which is operated in real model time, similar to that of an equivalent full scale turbine. Also, similar to that of a full scale wind turbine, the controls are developed in a Matlab Simulink environment. The current diagnostic system consists of power, rotor position, rotor speed measurements and PIV wake characterization with four cameras. The setup allows up to 7D downstream of the rotor to be mapped. The purpose of HAWKS is to simulate control strategies at turnaround times much faster than CFD and full scale testing. The fundamental building blocks of the simulator have been tested, and demonstrate wake steering for both static and dynamic turbine actuation. Parameters which have been studied are yaw, rotor speed and combinations hereof. The measured wake deflections for static yaw cases are in agreement with previously reported research implying general applicability of the HAWKS platform for the purpose of manipulating the wake. In this presentation the general results will be introduced followed by an analysis of the wake turbulence and coherent structures when comparing static and dynamic flow cases. The outcome of such studies could ultimately support effective wind farm wake flow control strategies. Texas Emerging Technology Fund (ETF).

  4. A Langevin model for fluctuating contact angle behaviour parametrised using molecular dynamics.

    Science.gov (United States)

    Smith, E R; Müller, E A; Craster, R V; Matar, O K

    2016-12-06

    Molecular dynamics simulations are employed to develop a theoretical model to predict the fluid-solid contact angle as a function of wall-sliding speed incorporating thermal fluctuations. A liquid bridge between counter-sliding walls is studied, with liquid-vapour interface-tracking, to explore the impact of wall-sliding speed on contact angle. The behaviour of the macroscopic contact angle varies linearly over a range of capillary numbers beyond which the liquid bridge pinches off, a behaviour supported by experimental results. Nonetheless, the liquid bridge provides an ideal test case to study molecular scale thermal fluctuations, which are shown to be well described by Gaussian distributions. A Langevin model for contact angle is parametrised to incorporate the mean, fluctuation and auto-correlations over a range of sliding speeds and temperatures. The resulting equations can be used as a proxy for the fully-detailed molecular dynamics simulation allowing them to be integrated within a continuum-scale solver.

  5. Dynamic modelling of high speed ballasted railway trakcs: Analysis of the behaviour

    Energy Technology Data Exchange (ETDEWEB)

    Gallego, I.; Rivas, A.; Sanchez-Cambronero, S.; Lajara, J.

    2016-07-01

    The aim of the paper is to present a numerical model for a ballasted railway track that includes the dynamic effect of a moving train load and predicts the values of the vertical stiffness of the infrastructure. This model is therefore deemed to be a tool for the evaluation of the state of the track during service situations as well as a predictive model of the behaviour of the system. Consequently, it will be very useful when sizing the cross section of a new railway line is required.The main modelling tool is the finite element method. In regard to this, the application of damping elements to avoid the elastic wave reflection on the boundaries of the numerical domain will be studied. The proposed dynamic analysis consider the change in time of the value of the train load, but not the change in position along the tracks.In the end, a set of suggestions for the numerical model with moving loads will be summarize aiming for the mitigation of the unusual behaviour of the contact surface between the ballast and the sleepers. (Author)

  6. Dynamic principle for ensemble control tools.

    Science.gov (United States)

    Samoletov, A; Vasiev, B

    2017-11-28

    Dynamical equations describing physical systems in contact with a thermal bath are commonly extended by mathematical tools called "thermostats." These tools are designed for sampling ensembles in statistical mechanics. Here we propose a dynamic principle underlying a range of thermostats which is derived using fundamental laws of statistical physics and ensures invariance of the canonical measure. The principle covers both stochastic and deterministic thermostat schemes. Our method has a clear advantage over a range of proposed and widely used thermostat schemes that are based on formal mathematical reasoning. Following the derivation of the proposed principle, we show its generality and illustrate its applications including design of temperature control tools that differ from the Nosé-Hoover-Langevin scheme.

  7. Nonsmooth mechanics models, dynamics and control

    CERN Document Server

    Brogliato, Bernard

    2016-01-01

    Now in its third edition, this standard reference is a comprehensive treatment of nonsmooth mechanical systems refocused to give more prominence to control and modelling. It covers Lagrangian and Newton–Euler systems, detailing mathematical tools such as convex analysis and complementarity theory. The ways in which nonsmooth mechanics influence and are influenced by well-posedness analysis, numerical analysis and simulation, modelling and control are explained. Contact/impact laws, stability theory and trajectory-tracking control are given in-depth exposition connected by a framework formed from complementarity systems and measure-differential inclusions. Links are established with electrical circuits with set-valued nonsmooth elements and with other nonsmooth dynamical systems like impulsive and piecewise linear systems. Nonsmooth Mechanics (third edition) has been substantially rewritten, edited and updated to account for the significant body of results that have emerged in the twenty-first century—incl...

  8. Cellular adhesome screen identifies critical modulators of focal adhesion dynamics, cellular traction forces and cell migration behaviour

    Science.gov (United States)

    Fokkelman, Michiel; Balcıoğlu, Hayri E.; Klip, Janna E.; Yan, Kuan; Verbeek, Fons J.; Danen, Erik H. J.; van de Water, Bob

    2016-01-01

    Cancer cells migrate from the primary tumour into surrounding tissue in order to form metastasis. Cell migration is a highly complex process, which requires continuous remodelling and re-organization of the cytoskeleton and cell-matrix adhesions. Here, we aimed to identify genes controlling aspects of tumour cell migration, including the dynamic organization of cell-matrix adhesions and cellular traction forces. In a siRNA screen targeting most cell adhesion-related genes we identified 200+ genes that regulate size and/or dynamics of cell-matrix adhesions in MCF7 breast cancer cells. In a subsequent secondary screen, the 64 most effective genes were evaluated for growth factor-induced cell migration and validated by tertiary RNAi pool deconvolution experiments. Four validated hits showed significantly enlarged adhesions accompanied by reduced cell migration upon siRNA-mediated knockdown. Furthermore, loss of PPP1R12B, HIPK3 or RAC2 caused cells to exert higher traction forces, as determined by traction force microscopy with elastomeric micropillar post arrays, and led to considerably reduced force turnover. Altogether, we identified genes that co-regulate cell-matrix adhesion dynamics and traction force turnover, thereby modulating overall motility behaviour. PMID:27531518

  9. Effect of composition on the high rate dynamic behaviour of tungsten heavy alloys

    Directory of Open Access Journals (Sweden)

    Latif Kesemen

    2015-01-01

    Full Text Available Tungsten heavy alloys are currently used as kinetic energy penetrators in military applications due to their high density and superior mechanical properties. In the literature, quasi-static properties of different tungsten heavy alloys based on W-Ni-Cu and W-Ni-Fe ternary systems are well documented and presented. However, comparison of the dynamic behaviour of these alloys in terms of the correlation between quasi-static mechanical characterization and dynamical properties is lacking. In the present study, dynamic properties of tungsten heavy alloys having different binder phase compositions (90W-7Ni-3Cu and 90W-8Ni-2Fe at different projectile velocities were investigated. The examined and tested alloys were produced through the conventional powder metallurgy route of mixing, cold compaction and sintering. Mechanical characterization of these alloys was performed. In the ballistic tests, cylindrical tungsten heavy alloys with L/D ratio of 3 were impacted to hardened steel target at different projectile velocities. After the ballistic tests, deformation characteristics of test specimens during dynamic loading were evaluated by comparing the change of length and diameter of the specimens versus kinetic energy densities. The study concluded that 90W-8Ni-2Fe alloy has better perforation characteristics than 90W-7Ni-3Cu alloy.

  10. Transformable ferroelectric control of dynamic magnetic permeability

    Science.gov (United States)

    Jiang, Changjun; Jia, Chenglong; Wang, Fenglong; Zhou, Cai; Xue, Desheng

    2018-02-01

    Magnetic permeability, which measures the response of a material to an applied magnetic field, is crucial to the performance of magnetic devices and related technologies. Its dynamic value is usually a complex number with real and imaginary parts that describe, respectively, how much magnetic power can be stored and lost in the material. Control of permeability is therefore closely related to energy redistribution within a magnetic system or energy exchange between magnetic and other degrees of freedom via certain spin-dependent interactions. To avoid a high power consumption, direct manipulation of the permeability with an electric field through magnetoelectric coupling leads to high efficiency and simple operation, but remains a big challenge in both the fundamental physics and material science. Here we report unambiguous evidence of ferroelectric control of dynamic magnetic permeability in a Co /Pb (Mg1/3Nb2/3) 0.7Ti0.3O3 (Co/PMN-PT) heterostructure, in which the ferroelectric PMN-PT acts as an energy source for the ferromagnetic Co film via an interfacial linear magnetoelectric interaction. The electric field tuning of the magnitude and line shape of the permeability offers a highly localized means of controlling magnetization with ultralow power consumption. Additionally, the emergence of negative permeability promises a new way of realizing functional nanoscale metamaterials with adjustable refraction index.

  11. Advances in dynamical systems and control

    CERN Document Server

    Zgurovsky, Mikhail

    2016-01-01

    Focused on recent advances, this book covers theoretical foundations as well as various applications. It presents modern mathematical modeling approaches to the qualitative and numerical analysis of solutions for complex engineering problems in physics, mechanics, biochemistry, geophysics, biology and climatology. Contributions by an international team of respected authors bridge the gap between abstract mathematical approaches, such as applied methods of modern analysis, algebra, fundamental and computational mechanics, nonautonomous and stochastic dynamical systems on the one hand, and practical applications in nonlinear mechanics, optimization, decision making theory and control theory on the other. As such, the book will be of interest to mathematicians and engineers working at the interface of these fields. .

  12. Cardea: Dynamic Access Control in Distributed Systems

    Science.gov (United States)

    Lepro, Rebekah

    2004-01-01

    Modern authorization systems span domains of administration, rely on many different authentication sources, and manage complex attributes as part of the authorization process. This . paper presents Cardea, a distributed system that facilitates dynamic access control, as a valuable piece of an inter-operable authorization framework. First, the authorization model employed in Cardea and its functionality goals are examined. Next, critical features of the system architecture and its handling of the authorization process are then examined. Then the S A M L and XACML standards, as incorporated into the system, are analyzed. Finally, the future directions of this project are outlined and connection points with general components of an authorization system are highlighted.

  13. HEALTH LOCUS OF CONTROL PERCEPTION OF ADOLESCENTS, AND ITS EFFECTS ON THEIR HEALTH BEHAVIOURS

    Directory of Open Access Journals (Sweden)

    Ruhi Selcuk TABAK

    2006-04-01

    Full Text Available Main objective of this study is to investigate the relationships between health locus of control perceptions and health behaviours of adolescents as well as the effectiveness of lectures on health locus of control to them. The subjects of our study are 192 students in 6 groups of the 9. Grade students of a high school. Three groups of 108 students were randomly selected as the experiment group who were subjected to 4 class-hours specific lectures on health locus of control. The rest 84 students constituted the control group. A 34-item questionnaire for health behaviours and the Multidimensional Health Locus of Control Scale (MHLOC, were filled by the students before and after the lectures. The lectures on health locus of control increased the perception of internal health locus of control of adolescents while decreasing chance health locus of control. The differences between experiment and control groups in this aspect were found to be statistically significant. Internal health locus of control is the main source for the increase of responsibility and management of individuals on their health. The relations that were detected between students’ health behaviours and information solicitation and their perceptions of health locus of control showed that the students with higher internal health locus of control are more eager to be responsible and active for their health, especially, for the health behaviours such as physical exercise, smoking, tooth-brushing, medical check-ups so on. [TAF Prev Med Bull 2006; 5(2.000: 118-130

  14. A dynamic model to explain hydration behaviour along the lanthanide series

    International Nuclear Information System (INIS)

    Duvail, M.; Spezia, R.; Vitorge, P.

    2008-01-01

    An understanding of the hydration structure of heavy atoms, such as transition metals, lanthanides and actinides, in aqueous solution is of fundamental importance in order to address their solvation properties and chemical reactivity. Herein we present a systematic molecular dynamics study of Ln 3+ hydration in bulk water that can be used as reference for experimental and theoretical research in this and related fields. Our study of hydration structure and dynamics along the entire Ln 3+ series provides a dynamic picture of the CN behavioural change from light (CN=9 predominating) to heavy (CN=8 predominating) lanthanides consistent with the exchange mechanism proposed by Helm, Merbach and co-workers. This scenario is summarized in this work. The hydrated light lanthanides are stable TTP structures containing two kinds of water molecules: six molecules forming the trigonal prism and three in the centre triangle. Towards the middle of the series both ionic radii and polarizabilities decrease, such that first-shell water-water repulsion increases and water-cation attraction decreases. This mainly applies for molecules of the centre triangle of the nine-fold structure. Thus, one of these molecules stay in the second hydration sphere of the lanthanide for longer average times, as one progresses along the lanthanide series. The interchange between predominantly CN=9 and CN=8 is found between Tb and Dy. Therefore, we propose a model that determines the properties governing the change in the first-shell coordination number across the series, confirming the basic hypothesis proposed by Helm and Merbach. We show that it is not a sudden change in behaviour, but rather that it results from a statistical predominance of one first hydration shell structure containing nine water molecules over one containing eight. This is observed progressively across the series. (O.M.)

  15. Dynamic Stall Control Using Plasma Actuators

    Science.gov (United States)

    Webb, Nathan; Singhal, Achal; Castaneda, David; Samimy, Mo

    2017-11-01

    Dynamic stall occurs in many applications, including sharp maneuvers of fixed wing aircraft, wind turbines, and rotorcraft and produces large unsteady aerodynamic loads that can lead to flutter and mechanical failure. This work uses flow control to reduce the unsteady loads by excitation of instabilities in the shear layer over the separated region using nanosecond pulse driven dielectric barrier discharge (NS-DBD) plasma actuators. These actuators have been shown to effectively delay or mitigate static stall. A wide range of flow parameters were explored in the current work: Reynolds number (Re = 167,000 to 500,000), reduced frequency (k = 0.025 to 0.075), and excitation Strouhal number (Ste = 0 to 10). Based on the results, three major conclusions were drawn: (a) Low Strouhal number excitation (Ste <0.5) results in oscillatory aerodynamic loads in the stalled stage of dynamic stall; (b) All excitation resulted in earlier flow reattachment; and (c) Excitation at progressively higher Ste weakened and eventually eliminated the dynamic stall vortex (DSV), thereby dramatically reducing the unsteady loading. The decrease in the strength of the DSV is achieved by the formation of shear layer coherent structures that bleed the leading-edge vorticity prior to the ejection of the DSV.

  16. Dynamic flowgraph modeling of process and control systems of a nuclear-based hydrogen production plant

    Energy Technology Data Exchange (ETDEWEB)

    Al-Dabbagh, Ahmad W. [Faculty of Engineering and Applied Science, University of Ontario Institute of Technology, 2000 Simcoe Street North, Oshawa, Ontario (Canada); Lu, Lixuan [Faculty of Energy Systems and Nuclear Science, Faculty of Engineering and Applied Science, University of Ontario Institute of Technology, 2000 Simcoe Street North, Oshawa, Ontario (Canada)

    2010-09-15

    Modeling and analysis of system reliability facilitate the identification of areas of potential improvement. The Dynamic Flowgraph Methodology (DFM) is an emerging discrete modeling framework that allows for capturing time dependent behaviour, switching logic and multi-state representation of system components. The objective of this research is to demonstrate the process of dynamic flowgraph modeling of a nuclear-based hydrogen production plant with the copper-chlorine (Cu-Cl) cycle. Modeling of the thermochemical process of the Cu-Cl cycle in conjunction with a networked control system proposed for monitoring and control of the process is provided. This forms the basis for future component selection. (author)

  17. Classical-driving-assisted entanglement dynamics control

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Ying-Jie, E-mail: yingjiezhang@qfnu.edu.cn [Shandong Provincial Key Laboratory of Laser Polarization and Information Technology, Department of Physics, Qufu Normal University, Qufu 273165 (China); Han, Wei [Shandong Provincial Key Laboratory of Laser Polarization and Information Technology, Department of Physics, Qufu Normal University, Qufu 273165 (China); Xia, Yun-Jie, E-mail: yjxia@qfnu.edu.cn [Shandong Provincial Key Laboratory of Laser Polarization and Information Technology, Department of Physics, Qufu Normal University, Qufu 273165 (China); Fan, Heng, E-mail: hfan@iphy.ac.cn [Beijing National Laboratory of Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190 (China); Collaborative Innovation Center of Quantum Matter, Beijing, 100190 (China)

    2017-04-15

    We propose a scheme of controlling entanglement dynamics of a quantum system by applying the external classical driving field for two atoms separately located in a single-mode photon cavity. It is shown that, with a judicious choice of the classical-driving strength and the atom–photon detuning, the effective atom–photon interaction Hamiltonian can be switched from Jaynes–Cummings model to anti-Jaynes–Cummings model. By tuning the controllable atom–photon interaction induced by the classical field, we illustrate that the evolution trajectory of the Bell-like entanglement states can be manipulated from entanglement-sudden-death to no-entanglement-sudden-death, from no-entanglement-invariant to entanglement-invariant. Furthermore, the robustness of the initial Bell-like entanglement can be improved by the classical driving field in the leaky cavities. This classical-driving-assisted architecture can be easily extensible to multi-atom quantum system for scalability.

  18. Hygiene behaviour and hospitalized severe childhood diarrhoea: a case-control study.

    Science.gov (United States)

    Baltazar, J C; Tiglao, T V; Tempongko, S B

    1993-01-01

    The relationship between personal and domestic hygiene behaviour and hospitalized childhood diarrhoea was examined in a case-control study of 356 cases and 357 controls from low-income families in metropolitan Manila. Indices of hygiene behaviour were defined for overall cleanliness, kitchen hygiene, and living conditions. Only the indices for overall cleanliness and kitchen hygiene were significantly associated with diarrhoea. An increasing excess risk of hospitalization with severe diarrhoea was noted as the ratings for standards of hygiene became lower, and this excess risk persisted even after controlling for confounding variables. The implications of our findings for the control of diarrhoeal disease are discussed.

  19. Control dynamics of interaction quenched ultracold bosons in periodically driven lattices

    Science.gov (United States)

    Mistakidis, Simeon; Schmelcher, Peter; Group of Fundamental Processes in Quantum Physics Team

    2016-05-01

    The out-of-equilibrium dynamics of ultracold bosons following an interaction quench upon a periodically driven optical lattice is investigated. It is shown that an interaction quench triggers the inter-well tunneling dynamics, while for the intra-well dynamics breathing and cradle-like processes can be generated. In particular, the occurrence of a resonance between the cradle and tunneling modes is revealed. On the other hand, the employed periodic driving enforces the bosons in the mirror wells to oscillate out-of-phase and to exhibit a dipole mode, while in the central well the cloud experiences a breathing mode. The dynamical behaviour of the system is investigated with respect to the driving frequency revealing a resonant behaviour of the intra-well dynamics. To drive the system in a highly non-equilibrium state an interaction quench upon the driving is performed giving rise to admixtures of excitations in the outer wells, an enhanced breathing in the center and an amplification of the tunneling dynamics. As a result of the quench the system experiences multiple resonances between the inter- and intra-well dynamics at different quench amplitudes. Deutsche Forschungsgemeinschaft, SFB 925 ``Light induced dynamics and control of correlated quantum systems''.

  20. NASA Armstrong Flight Research Center Dynamics and Controls Branch

    Science.gov (United States)

    Jacobson, Steve

    2015-01-01

    NASA Armstrong continues its legacy of exciting work in the area of Dynamics and Control of advanced vehicle concepts. This presentation describes Armstrongs research in control of flexible structures, peak seeking control and adaptive control in the Spring of 2015.

  1. Experimental research project on the dynamic behaviour of Garigliano N.P.P

    International Nuclear Information System (INIS)

    Sano, Tito; Vitiello, Edmondo

    1988-01-01

    The Garigliano N.P.P., 150 MW electric and 500 MW thermic, was built from 1961- to 1964. During 1980 it was shut down and thereafter the decommissioning procedure was started. In 1984 ENEA-DISP sponsored a preliminary study for a program of on-site experimental research on the Garigliano plant as part of a more general research program on seismic safety margin assessments. This paper presents the main conclusions of this preliminary study. For the research concerning the dynamic behaviour, some features have been pointed out: a) The Garigliano N.P.P. gives the opportunity to get some results on the soil-structure interaction in the interesting case of soft-soil (indefinite layer). b) The interaction structure-soil-structure can be tested between reactor building and turbine that are separated by an expansion-joint (extending in the mat too). c) The spherical steel containment has no other structural connections with the inner reinforced concrete structure than at the foundation level and therefore it may give clean experimental results on the dynamic behaviour of the containment alone. d) The H/B (height/base) ratio of the reactor building is sufficiently low to obtain translational modes of the structure. The research program is subdivided into many phases. The ones concerning the overall structure behaviour are as following: 1) Excitation by underground explosions. 2) Excitation by actuators on the mat using as reaction mass a concrete slab (ad hoc built aside). The latter is also used to compare the dynamic foundation response with and without micropiles. 3) Excitation by shakers inside the reactor building (at the top of the concrete structure). 4) Impact tests on the external R.C. wall of the turbine building. Others phases of research program are related to the tests of aged components on site and on shaking table (up to failure load). At the end of this paper an outline of the first experiment (excitation by explosion) and some results are presented. (author)

  2. Model-Based Brake Control including Tyre Behaviour

    NARCIS (Netherlands)

    De Vries, E.J.H.

    2012-01-01

    The objective of the thesis is to develop a method for controlled braking of a vehicle. The brake pedal depression has been considered to be proportional to the intended deceleration. The brake controller is not aimed to replace a cruise control; it will have an anti-lock braking (ABS) function. The

  3. Soil non-linearity and its effect on the dynamic behaviour of offshore platform foundations

    Energy Technology Data Exchange (ETDEWEB)

    Madshus, Christian

    1997-07-01

    This thesis focuses on non-linear soil response to the type of cyclic loading experienced under offshore gravity base platform foundations. These loads are dominated by a cyclic component around the main wave frequency, which may well mobilize soil non-linearity under severe sea-states. Superimposed on this main component are lower level higher frequency loads caused by resonant oscillations of the platform. The thesis presents results of specially designed triaxial tests to simulate this loading condition. The tests simultaneously applied two cyclic load components at different frequencies and amplitudes. The measured soil response to each component has been isolated through a frequency domain separation. It was found that the soil responds to the superimposed high frequency low level component as if the soil had a cyclically time-varying stiffness. If the superimposed component does not lead to load reversals, this stiffness variation is controlled by the frequency and amplitude of the main load component and by the hysteretic non-linearity of the soil. If the superimposed component causes reversals, the influence of the hysteretic non-linearity on the stiffness variation is reduced. The higher the degree of reversal, the more this influence it taken over by the variation in the instantaneous unloading-reloading stiffness of the soil. It was also found that this type of two-frequency cyclic soil testing is generally superior over conventional single-frequency testing in the way it enforces the soil to reveal several of its inherent properties not deducible from ordinary tests. Benefits of analyzing non-linear response in the frequency domain is demonstrated throughout this thesis. The ability of various theoretical soil models to simulate the observed soil behaviour under two-frequency cyclic loading has, been investigated through numerical analyses. It was found that only those models that are based on kinematic hardening are able to reproduce what was observed

  4. The walking behaviour of pedestrian social groups and its impact on crowd dynamics.

    Directory of Open Access Journals (Sweden)

    Mehdi Moussaïd

    Full Text Available Human crowd motion is mainly driven by self-organized processes based on local interactions among pedestrians. While most studies of crowd behaviour consider only interactions among isolated individuals, it turns out that up to 70% of people in a crowd are actually moving in groups, such as friends, couples, or families walking together. These groups constitute medium-scale aggregated structures and their impact on crowd dynamics is still largely unknown. In this work, we analyze the motion of approximately 1500 pedestrian groups under natural condition, and show that social interactions among group members generate typical group walking patterns that influence crowd dynamics. At low density, group members tend to walk side by side, forming a line perpendicular to the walking direction. As the density increases, however, the linear walking formation is bent forward, turning it into a V-like pattern. These spatial patterns can be well described by a model based on social communication between group members. We show that the V-like walking pattern facilitates social interactions within the group, but reduces the flow because of its "non-aerodynamic" shape. Therefore, when crowd density increases, the group organization results from a trade-off between walking faster and facilitating social exchange. These insights demonstrate that crowd dynamics is not only determined by physical constraints induced by other pedestrians and the environment, but also significantly by communicative, social interactions among individuals.

  5. PLAT: An Automated Fault and Behavioural Anomaly Detection Tool for PLC Controlled Manufacturing Systems

    Directory of Open Access Journals (Sweden)

    Arup Ghosh

    2016-01-01

    Full Text Available Operational faults and behavioural anomalies associated with PLC control processes take place often in a manufacturing system. Real time identification of these operational faults and behavioural anomalies is necessary in the manufacturing industry. In this paper, we present an automated tool, called PLC Log-Data Analysis Tool (PLAT that can detect them by using log-data records of the PLC signals. PLAT automatically creates a nominal model of the PLC control process and employs a novel hash table based indexing and searching scheme to satisfy those purposes. Our experiments show that PLAT is significantly fast, provides real time identification of operational faults and behavioural anomalies, and can execute within a small memory footprint. In addition, PLAT can easily handle a large manufacturing system with a reasonable computing configuration and can be installed in parallel to the data logging system to identify operational faults and behavioural anomalies effectively.

  6. PLAT: An Automated Fault and Behavioural Anomaly Detection Tool for PLC Controlled Manufacturing Systems.

    Science.gov (United States)

    Ghosh, Arup; Qin, Shiming; Lee, Jooyeoun; Wang, Gi-Nam

    2016-01-01

    Operational faults and behavioural anomalies associated with PLC control processes take place often in a manufacturing system. Real time identification of these operational faults and behavioural anomalies is necessary in the manufacturing industry. In this paper, we present an automated tool, called PLC Log-Data Analysis Tool (PLAT) that can detect them by using log-data records of the PLC signals. PLAT automatically creates a nominal model of the PLC control process and employs a novel hash table based indexing and searching scheme to satisfy those purposes. Our experiments show that PLAT is significantly fast, provides real time identification of operational faults and behavioural anomalies, and can execute within a small memory footprint. In addition, PLAT can easily handle a large manufacturing system with a reasonable computing configuration and can be installed in parallel to the data logging system to identify operational faults and behavioural anomalies effectively.

  7. Characterization of fluid dynamic behaviour and channel wall effects in microtube

    International Nuclear Information System (INIS)

    Celata, G.P.; Cumo, M.; McPhail, S.; Zummo, G.

    2006-01-01

    Sometimes contradictory results available for fluid flow in micropipes show that much is yet to be verified in microfluid dynamics. In this study the influence of channel wall roughness and of channel wall hydrophobicity on adiabatic flow in circular microchannels is investigated, varying in diameter from 70 μm to 326 μm. The hydrodynamic behaviour of water in smooth tubes down to 30 μm inner diameter (ID) is also ascertained. Within the current experimental accuracy it is found that the classical Hagen-Poiseuille law for friction factor vs. Reynolds number is respected for all diameters measured and Re > 300. With degassed water, no effect of slip flow due to hydrophobic channel walls was noted even at 70 μm ID, which might suggest that the liquid slip flow phenomenon is associated with local desorption of dissolved gases on the hydrophobic surface, as reported elsewhere in the literature. For roughened glass channels, an increase in Darcy friction factor above 64/Re was observed only at the smallest diameter measured, 126 μm. Although the roughness levels of these channels were up to 10 times coarser than the untreated, smooth glass tubes, probably the higher factor was caused by actual deformation of channel circularity, rather than increased friction at the rougher wall, as similar behaviour was observed in a Teflon tube, also of imperfect circularity of cross-section. For all experiments, no anticipated transition to turbulent flow was observed, which means that the transitional Reynolds number was always found between Re ∼ 2000 and Re ∼ 3000. Finally, an introduction to the importance of viscous dissipation in microchannels is added, with quantitative indications of its influence on hydrodynamic properties. It is put forward as being an alternative to pressure measurements in the characterization of the behaviour of microscopic flow

  8. Activity in the superior colliculus reflects dynamic interactions between voluntary and involuntary influences on orienting behaviour.

    Science.gov (United States)

    Bell, Andrew H; Munoz, Douglas P

    2008-10-01

    Performance in a behavioural task can be influenced by both bottom-up and top-down processes such as stimulus modality and prior probability. Here, we exploited differences in behavioural strategy to explore the role of the intermediate and deep layers of the superior colliculus (dSC) in covert orienting. Two monkeys were trained on a predictive cued-saccade task in which the cue predicted the target's upcoming location with 80% validity. When the delay between cue and target onset was 250 ms, both monkeys showed faster responses to the uncued (Invalid) location. This was associated with a reduced target-aligned response in the dSC on Valid trials for both monkeys and is consistent with a bottom-up (i.e. involuntary) bias. When the delay was increased to 650 ms, one monkey continued to show faster responses to the Invalid location whereas the other monkey showed faster responses to the Valid location, consistent with a top-down (i.e. voluntary) bias. This latter behaviour was correlated with an increase in activity in dSC neurons preceding target onset that was absent in the other monkey. Thus, using the information provided by the cue shifted the emphasis towards top-down processing, while ignoring this information allowed bottom-up processing to continue to dominate. Regardless of the selected strategy, however, neurons in the dSC consistently reflected the current bias between the two processes, emphasizing its role in both the bottom-up and top-down control of orienting behaviour.

  9. Co-percolation to tune conductive behaviour in dynamical metallic nanowire networks.

    Science.gov (United States)

    Fairfield, J A; Rocha, C G; O'Callaghan, C; Ferreira, M S; Boland, J J

    2016-11-03

    Nanowire networks act as self-healing smart materials, whose sheet resistance can be tuned via an externally applied voltage stimulus. This memristive response occurs due to modification of junction resistances to form a connectivity path across the lowest barrier junctions in the network. While most network studies have been performed on expensive noble metal nanowires like silver, networks of inexpensive nickel nanowires with a nickel oxide coating can also demonstrate resistive switching, a common feature of metal oxides with filamentary conduction. However, networks made from solely nickel nanowires have high operation voltages which prohibit large-scale material applications. Here we show, using both experiment and simulation, that a heterogeneous network of nickel and silver nanowires allows optimization of the activation voltage, as well as tuning of the conduction behavior to be either resistive switching, memristive, or a combination of both. Small percentages of silver nanowires, below the percolation threshold, induce these changes in electrical behaviour, even for low area coverage and hence very transparent films. Silver nanowires act as current concentrators, amplifying conductivity locally as shown in our computational dynamical activation framework for networks of junctions. These results demonstrate that a heterogeneous nanowire network can act as a cost-effective adaptive material with minimal use of noble metal nanowires, without losing memristive behaviour that is essential for smart sensing and neuromorphic applications.

  10. Effect of graphene oxide nano filler on dynamic behaviour of GFRP composites

    Science.gov (United States)

    Pujar, Nagabhushan V.; Nanjundaradhya, N. V.; Sharma, Ramesh S.

    2018-04-01

    Nano fillers like Alumina oxide, Titanium oxide, Carbon nano tube, Nano clay have been used to improve the mechanical and damping properties of fiber reinforced polymer composites. In the recent years Graphene oxide nano filler is receiving considerable attention for its outstanding properties. Literature available shows that Graphene oxide nano filler can be used to improve the mechanical properties. The use of Graphene oxide in vibration attenuation by enhancing the passive damping in fiber reinforced polymer composite has not been fully explored. The objective of this work is to investigate the dynamic behaviour of Glass fiber-reinforced composite embedded with Graphene oxide nano filler. Graphene oxide is dispersed in epoxy resin with various concentration (0.1%, 0.5% and 1%wt) using ultra-sonification process. Composite laminates were made using the traditional hand-lay-up followed by vacuum bag process. Experimental modal analysis using traditional `strike method' is used to evaluate modal parameters using FFT analyzer and Data Acquisition System. Experiments were carried out for two different fiber orientations viz 0 ➙ & 45 ➙ and two boundary conditions (Free-Free and Cantilever). The modal parameters such as natural frequency, mode shape, damping ratio were studied. This research work demonstrates the vibration damping behaviour with incorporation of Graphene oxide and provides a basic understanding of the damping characteristics in design and manufacture of high performance composites.

  11. Modelling of the dynamical behaviour of LWR internals by homogeneization methods

    International Nuclear Information System (INIS)

    Brochard, D.; Lepareux, M.; Gibert, R.J.; Delaigue, D.; Planchard, J.

    1987-01-01

    The upper plenum of the internals of PWR, the steam generator bundle, the nuclear reactor core, may be schematically represented by a beam bundle immersed in a fluid. The dynamical study of such a system needs to take into account fluid structure interaction. A refined modelisation at the scale of the tubes can be used but leads to a very important size of problem difficult to solve even on the biggest computers. The homogeneization method allows to have an approximation of the fluid structure interaction for the global behaviour of the bundle. It consists in replacing the heterogeneous physical medium (tubes and fluid) by an equivalent homogeneous medium whose characteristics are determined from the resolution of a set of problems on the elementary cell. The aim of this paper is to present the main steps of the determination of this equivalent medium in the case of small displacements (acoustic behaviour of the fluid) and in using displacement variables for both fluid and tubes. Then some precisions about the implementation of this method in computer codes will be given. (orig.)

  12. Dynamic behaviour of high-pressure natural-gas flow in pipelines

    International Nuclear Information System (INIS)

    Gato, L.M.C.; Henriques, J.C.C.

    2005-01-01

    The aim of the present study is the numerical modelling of the dynamic behaviour of high-pressure natural-gas flow in pipelines. The numerical simulation was performed by solving the conservation equations, for one-dimensional compressible flow, using the Runge-Kutta discontinuous Galerkin method, with third-order approximation in space and time. The boundary conditions were imposed using a new weak formulation based on the characteristic variables. The occurrence of pressure oscillations in natural-gas pipelines was studied as a result of the compression wave originated by the rapid closure of downstream shut-off valves. The effect of the partial reflection of pressure waves was also analyzed in the transition between pipes of different cross-sectional areas

  13. Dynamic behaviour of high-pressure natural-gas flow in pipelines

    Energy Technology Data Exchange (ETDEWEB)

    Gato, L.M.C. [Department of Mechanical Engineering, Instituto Superior Tecnico, Technical University of Lisbon, Av. Rovisco Pais, 1049-001 Lisbon (Portugal)]. E-mail: lgato@mail.ist.utl.pt; Henriques, J.C.C. [Department of Mechanical Engineering, Instituto Superior Tecnico, Technical University of Lisbon, Av. Rovisco Pais, 1049-001 Lisbon (Portugal)]. E-mail: jcch@mail.ist.utl.pt

    2005-10-01

    The aim of the present study is the numerical modelling of the dynamic behaviour of high-pressure natural-gas flow in pipelines. The numerical simulation was performed by solving the conservation equations, for one-dimensional compressible flow, using the Runge-Kutta discontinuous Galerkin method, with third-order approximation in space and time. The boundary conditions were imposed using a new weak formulation based on the characteristic variables. The occurrence of pressure oscillations in natural-gas pipelines was studied as a result of the compression wave originated by the rapid closure of downstream shut-off valves. The effect of the partial reflection of pressure waves was also analyzed in the transition between pipes of different cross-sectional areas.

  14. Effect of Peierls transition in armchair carbon nanotube on dynamical behaviour of encapsulated fullerene

    Directory of Open Access Journals (Sweden)

    Hieu Nguyen

    2011-01-01

    Full Text Available Abstract The changes of dynamical behaviour of a single fullerene molecule inside an armchair carbon nanotube caused by the structural Peierls transition in the nanotube are considered. The structures of the smallest C20 and Fe@C20 fullerenes are computed using the spin-polarized density functional theory. Significant changes of the barriers for motion along the nanotube axis and rotation of these fullerenes inside the (8,8 nanotube are found at the Peierls transition. It is shown that the coefficients of translational and rotational diffusions of these fullerenes inside the nanotube change by several orders of magnitude. The possibility of inverse orientational melting, i.e. with a decrease of temperature, for the systems under consideration is predicted.

  15. The dynamics of absence behaviour: Interrelations between absence from class and absence in class

    DEFF Research Database (Denmark)

    Jonasson, Charlotte

    2011-01-01

    Abstract: Background: Studies of absence in educational settings have primarily been concerned with the causes for and results of student absence. However, recent research has argued that distinguishing between different forms of absence could be important. In consequence, studying the way in whi...... in the social practice of students, teachers and school managers. Evaluations of both absence from class and absence in class are important for understanding how absence behaviour can be identified and prevented....... performance. It is helpful to describe these findings using theoretical frameworks from sociology and psychology: specifically, spill-over theory and symbolic capital theory. Conclusions: This study has demonstrated how different forms of absence become dynamically interrelated through ongoing negotiations...

  16. Dynamic tensile behaviour and deformational mechanism of C5191 phosphor bronze under high strain rates deformation

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Dao-chun [College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); College of Mechanical and Electrical Engineering, Taizhou Vocational & Technical College, Taizhou 318000 (China); Chen, Ming-he, E-mail: meemhchen@nuaa.edu.cn [College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Wang, Lei; Cheng, Hu [College of Mechanical Engineering, Taizhou University, Taizhou 318000 (China)

    2016-01-01

    High speed stamping process is used to high strength and high electrical conductivity phosphor bronze with extremely high strain rates more than 10{sup 3} s{sup −1}. This study on the dynamic tensile behaviour and deformational mechanism is to optimise the high speed stamping processes and improve geometrical precision in finished products. Thus, the tensile properties and deformation behaviour of C5191 phosphor bronze under quasi-static tensile condition at a strain rate of 0.001 s{sup −1} by electronic universal testing machine, and dynamic tensile condition at strain rate of 500, 1000 and 1500 s{sup −1} by split Hopkinson tensile bar (SHTB) apparatus were studied. The effects of strain rate and the deformation mechanism were investigated by means of SEM and TEM. The results showed that the yield strength and tensile strength of C5191 phosphor bronze under high strain rates deformation increased by 32.77% and 11.07% respectively compared with quasi-static condition, the strain hardening index increases from 0.075 to 0.251, and the strength of the material strain rates sensitivity index change from 0.005 to 0.022, which presented a clear sensitive to strain rates. Therefore, it is claimed that the dominant deformation mechanism was changed by the dislocation motion under different strain rates, and the ability of plastic deformation of C5191 phosphor bronze increased due to the number of movable dislocations increased significantly, started multi-line slip, and the soft effect of adiabatic temperature rise at the strain rate ranging from 500 to 1500 s{sup −1}.

  17. Surface conductivity dependent dynamic behaviour of an ultrafine atmospheric pressure plasma jet for microscale surface processing

    Energy Technology Data Exchange (ETDEWEB)

    Abuzairi, Tomy [Graduate School of Science and Technology, Shizuoka University, Hamamatsu 432-8561 (Japan); Department of Electrical Engineering, Faculty of Engineering, Universitas Indonesia, Depok 16424 (Indonesia); Okada, Mitsuru [Department of Engineering, Shizuoka University, Hamamatsu 432-8561 (Japan); Bhattacharjee, Sudeep [Department of Physics, Indian Institute of Technology, Kanpur 208016 (India); Nagatsu, Masaaki, E-mail: nagatsu.masaaki@shizuoka.ac.jp [Graduate School of Science and Technology, Shizuoka University, Hamamatsu 432-8561 (Japan); Department of Engineering, Shizuoka University, Hamamatsu 432-8561 (Japan); Research Institute of Electronics, Shizuoka University, Hamamatsu 432-8561 (Japan)

    2016-12-30

    Highlights: • Spatio-temporal behaviors of capillary APPJs are studied for various substrates. • Plasma irradiation area depended on the substrate conductivity and permittivity. • Surface irradiation area was significantly broadened in polymer-like substrate. • Effect of applying a substrate bias on the APPJ irradiation area was investigated. - Abstract: An experimental study on the dynamic behaviour of microcapillary atmospheric pressure plasma jets (APPJs) with 5 μm tip size for surfaces of different conductivity is reported. Electrical and spatio-temporal characteristics of the APPJs are monitored using high voltage probe, current monitor and high speed intensified charge couple device camera. From these experimental results, we presented a simple model to understand the electrical discharge characteristics of the capillary APPJs with double electrodes, and estimated the velocity of the ionization fronts in the jet and the electron density to be 3.5–4.2 km/s and 2–7 × 10{sup 17} m{sup −3}. By analyzing the dynamics of the microcapillary APPJs for different substrate materials, it was found that the surface irradiation area strongly depended on the substrate conductivity and permittivity, especially in the case of polymer-like substrate, surface irradiation area was significantly broadened probably due to the repelling behaviour of the plasma jets from the accumulated electrical charges on the polymer surface. The effect of applying a substrate bias in the range from −900 V to +900 V on the plasma irradiation onto the substrates was also investigated. From the knowledge of the present results, it is helpful for choosing the substrate materials for microscale surface modification.

  18. Surface conductivity dependent dynamic behaviour of an ultrafine atmospheric pressure plasma jet for microscale surface processing

    International Nuclear Information System (INIS)

    Abuzairi, Tomy; Okada, Mitsuru; Bhattacharjee, Sudeep; Nagatsu, Masaaki

    2016-01-01

    Highlights: • Spatio-temporal behaviors of capillary APPJs are studied for various substrates. • Plasma irradiation area depended on the substrate conductivity and permittivity. • Surface irradiation area was significantly broadened in polymer-like substrate. • Effect of applying a substrate bias on the APPJ irradiation area was investigated. - Abstract: An experimental study on the dynamic behaviour of microcapillary atmospheric pressure plasma jets (APPJs) with 5 μm tip size for surfaces of different conductivity is reported. Electrical and spatio-temporal characteristics of the APPJs are monitored using high voltage probe, current monitor and high speed intensified charge couple device camera. From these experimental results, we presented a simple model to understand the electrical discharge characteristics of the capillary APPJs with double electrodes, and estimated the velocity of the ionization fronts in the jet and the electron density to be 3.5–4.2 km/s and 2–7 × 10"1"7 m"−"3. By analyzing the dynamics of the microcapillary APPJs for different substrate materials, it was found that the surface irradiation area strongly depended on the substrate conductivity and permittivity, especially in the case of polymer-like substrate, surface irradiation area was significantly broadened probably due to the repelling behaviour of the plasma jets from the accumulated electrical charges on the polymer surface. The effect of applying a substrate bias in the range from −900 V to +900 V on the plasma irradiation onto the substrates was also investigated. From the knowledge of the present results, it is helpful for choosing the substrate materials for microscale surface modification.

  19. Dynamic control of knee axial deformities

    Directory of Open Access Journals (Sweden)

    E. E. Malyshev

    2013-01-01

    Full Text Available The authors have evaluated the clinical examination of the patients with axial malalignments in the knee by the original method and device which was named varovalgometer. The measurements were conducted by tension of the cord through the spina iliaca anterior superior and the middle of the lower pole of patella. The deviation of the center of the ankle estimated by metal ruler which was positioned perpendicular to the lower leg axis on the level of the ankle joint line. The results of comparison of our method and computer navigation in 53 patients during the TKA show no statistically significant varieties but they differ by average 5° of valgus in clinical examination in comparison with mechanical axis which was identified by computer navigation. The dynamic control of axial malalignment can be used in clinical practice for estimation of the results of treatment of pathology with axial deformities in the knee; for the control of reduction and secondary displacement of the fractures around the knee; for assessment of instability; in planning of correctional osteotomies and intraoperative control of deformity correction; for estimation of Q angle in subluxation and recurrent dislocation of patella; in planning of TKA; during the growth of child it allows to assess the progression of deformity.

  20. Experimental targeting of chaos via controlled symbolic dynamics

    International Nuclear Information System (INIS)

    Corron, Ned J.; Pethel, Shawn D.

    2003-01-01

    In this Letter, we report experimental targeting in a chaotic system by controlling symbolic dynamics. We acquire and control an electronic circuit using small perturbations to elicit a desired objective state starting from an arbitrary, uncontrolled state. The control perturbations are calculated using a symbolic targeting sequence and applied using dynamic limiting control

  1. Health Locus of Control and Preventive Behaviour among Students of Music

    Science.gov (United States)

    Spahn, Claudia; Burger, Thorsten; Hildebrandt, Horst; Seidenglanz, Karin

    2005-01-01

    The present study investigated health locus of control, preventive behaviour and previous playing-related health problems of music students; 326 students of music (58% female, mean age 22 years) filled in the Locus of Control Inventory for Illness and Health (Lohaus and Schmitt, 1989) and the Epidemiological Questionnaire for Musicians (Spahn,…

  2. Mobile phone SMS messages can enhance healthy behaviour: a meta-analysis of randomised controlled trials.

    Science.gov (United States)

    Orr, Jayne A; King, Robert J

    2015-01-01

    Healthy behaviour, such as smoking cessation and adherence to prescribed medications, mitigates illness risk factors but health behaviour change can be challenging. Mobile phone short-message service (SMS) messages are increasingly used to deliver interventions designed to enhance healthy behaviour. This meta-analysis used a random-effects model to synthesise 38 randomised controlled trials that investigated the efficacy of SMS messages to enhance healthy behaviour. Participants (N = 19,641) lived in developed and developing countries and were diverse with respect to age, ethnicity, socioeconomic background and health behaviours targeted for change. SMS messages had a small, positive, significant effect (g = 0.291) on a broad range of healthy behaviour. This effect was maximised when multiple SMS messages per day were used (g = 0.395) compared to using lower frequencies (daily, multiple per week and once-off) (g = 0.244). The low heterogeneity in this meta-analysis (I (2) = 38.619) supports reporting a summary effect size and implies that the effect of SMS messaging is robust, regardless of population characteristics or healthy behaviour targeted. SMS messaging is a simple, cost-effective intervention that can be automated and can reach any mobile phone owner. While the effect size is small, potential health benefits are well worth achieving.

  3. Dynamic environmental control mechanisms for pneumatic foil constructions

    Science.gov (United States)

    Flor, Jan-Frederik; Wu, Yupeng; Beccarelli, Paolo; Chilton, John

    2017-11-01

    Membrane and foil structures have become over the last decades an attractive alternative to conventional materials and building systems with increasing implementation in different typologies and scale. The development of transparent, light, flexible and resistant materials like Ethylene Tetrafluoroethylene (ETFE) has triggered a rethinking of the building envelope in the building industry towards lightweight systems. ETFE foil cushions have proven to fulfil the design requirements in terms of structural efficiency and aesthetic values. But the strategies to satisfy increasing demands of energy efficiency and comfort conditions are still under development. The prediction and manipulation of the thermo-optical behaviour of ETFE foil cushion structures currently remain as one of the main challenges for designers and manufacturers. This paper reviews ongoing research regarding the control of the thermo-optical performance of ETFE cushion structures and highlights challenges and possible improvements. An overview of different dynamic and responsive environmental control mechanisms for multilayer foil constructions is provided and the state of the art in building application outlined by the discussion of case studies.

  4. Asynchronous control of Distributed Energy Resources using behaviour descriptions

    DEFF Research Database (Denmark)

    Kullmann, Daniel; Gehrke, Oliver; Bindner, Henrik

    2012-01-01

    The activation of power system services from small DER is a key to building electrical power systems with a high penetrations of renewable generation. Reliable, real-time and low-cost communication to a large number of DER units is required for controlling these resources, but difficult to achiev....... This paper presents an alternative to traditional closed-loop control which has the potential to relax the real-time requirements on the communication link between supervisory controller and DER unit. Examples are given, and experimental results are provided as a proof-of-concept....

  5. Animal thermoregulation: a review of insulation, physiology and behaviour relevant to temperature control in buildings.

    Science.gov (United States)

    McCafferty, D J; Pandraud, G; Gilles, J; Fabra-Puchol, M; Henry, P-Y

    2017-12-28

    Birds and mammals have evolved many thermal adaptations that are relevant to the bioinspired design of temperature control systems and energy management in buildings. Similar to many buildings, endothermic animals generate internal metabolic heat, are well insulated, regulate their temperature within set limits, modify microclimate and adjust thermal exchange with their environment. We review the major components of animal thermoregulation in endothermic birds and mammals that are pertinent to building engineering, in a world where climate is changing and reduction in energy use is needed. In animals, adjustment of insulation together with physiological and behavioural responses to changing environmental conditions fine-tune spatial and temporal regulation of body temperature, while also minimizing energy expenditure. These biological adaptations are characteristically flexible, allowing animals to alter their body temperatures to hourly, daily, or annual demands for energy. They exemplify how buildings could become more thermally reactive to meteorological fluctuations, capitalising on dynamic thermal materials and system properties. Based on this synthesis, we suggest that heat transfer modelling could be used to simulate these flexible biomimetic features and assess their success in reducing energy costs while maintaining thermal comfort for given building types.

  6. Rheological behaviour and physical properties of controlled-release gluten-based bioplastics.

    Science.gov (United States)

    Gómez-Martínez, D; Partal, P; Martínez, I; Gallegos, C

    2009-03-01

    Bioplastics based on glycerol, water and wheat gluten have been manufactured in order to determine the effect that mechanical processing and further thermal treatments exert on different thermo-mechanical properties of the biomaterials obtained. An "active agent", KCl was incorporated in these matrices to develop controlled-release formulations. Oscillatory shear, dynamic mechanical thermal analysis (DMTA), diffusion and water absorption tests were carried out in order to study the influence of the above-mentioned treatments on the physico-chemical characteristics and rheological behaviour of these bioplastic samples. Wheat gluten protein-based bioplastics studied in this work present a high ability for thermosetting modification, due to protein denaturation, which may favour the development of a wide variety of biomaterials. Bioplastic hygroscopic properties depend on plasticizer nature and processing procedure, and may be a key factor for industrial applications where water absorption is required. On the other hand, high water absorption and slow KCl release from bioplastic samples (both of them suitable properties in agricultural applications) may be obtained by adding citric acid to a given formulation, at selected processing conditions.

  7. Chaotic behaviour in the non-linear optimal control of unilaterally contacting building systems during earthquakes

    International Nuclear Information System (INIS)

    Liolios, A.A.; Boglou, A.K.

    2003-01-01

    The paper presents a new numerical approach for a non-linear optimal control problem arising in earthquake civil engineering. This problem concerns the elastoplastic softening-fracturing unilateral contact between neighbouring buildings during earthquakes when Coulomb friction is taken into account under second-order instabilizing effects. So, the earthquake response of the adjacent structures can appear instabilities and chaotic behaviour. The problem formulation presented here leads to a set of equations and inequalities, which is equivalent to a dynamic hemivariational inequality in the way introduced by Panagiotopoulos [Hemivariational Inequalities. Applications in Mechanics and Engineering, Springer-Verlag, Berlin, 1993]. The numerical procedure is based on an incremental problem formulation and on a double discretization, in space by the finite element method and in time by the Wilson-θ method. The generally non-convex constitutive contact laws are piecewise linearized, and in each time-step a non-convex linear complementarity problem is solved with a reduced number of unknowns

  8. Dynamics and control of electrical drives

    Energy Technology Data Exchange (ETDEWEB)

    Wach, Piotr [Politechnika Opolska, Opole (Poland). Inst. of Electromechanical Systems and Applied Informatics

    2011-07-01

    Dynamics is a science concerned with movement and changes. In the most general approach it relates to life processes as well as behavior in nature in rest. It governs small particles, technical objects, conversion of matter and materials but also concerns people, groups of people in their individual and, in particular, social dimension. In dynamics we always have to do with causes or stimuli for motion, the rules of reaction or behavior and its result in the form of trajectory of changes. This book is devoted to dynamics of a wide class of specific but very important objects such as electromechanical systems. This is a very rigorous discipline and has a long tradition, as its theoretical bases were formulated in the first half of the XIX century by d' Alembert, Lagrange, Hamilton, Maxwell and other prominent scientists, but their crucial results were based on previous pioneering research of others such as Copernicus, Galileo, Newton..This book in its theoretical foundations is based on the principle of least action which governs classical as well as relativistic mechanics and electromagnetism and leads to Lagrange's equations which are applied in the book as universal method to construct equations of motion of electromechanical systems. It gives common and coherent grounds to formulate mathematical models for all lumped parameters' electromechanical systems, which are vital in our contemporary industry and civilized everyday life. From these remarks it seems that the book is general and theoretical but in fact it is a very practical one concerning modern electrical drives in a broad sense, including electromechanical energy conversion, induction motor drives, brushless DC drives with a permanent magnet excitation and switched reluctance machines (SRM). And of course their control, which means shaping of their trajectories of motion using modern tools, their designed autonomy in keeping a track according to our programmed expectations. The problems

  9. Knowledge of HIV/AIDS, attitudes towards sexual risk behaviour and perceived behavioural control among college students in Botswana

    Directory of Open Access Journals (Sweden)

    Gabriel Faimau

    2016-12-01

    Full Text Available This study examines the knowledge of HIV/AIDS, attitudes towards risky sexual behaviour and perceived behavioural control among students in Botswana. Data were collected from 445 students randomly selected from the University of Botswana and Boitekanelo College. Hundred and seventy three males and 272 females participated in the study. The study established that although more than 90% of students correctly identified routes of HIV transmission, misconceptions regarding HIV/AIDS still exist. This includes the belief that people can be infected with HIV because of witchcraft and that only people who have sex with gay or homosexual partners can be infected with HIV. Majority of students were aware of various sexual risks. However, the percentage of students who indicated that “it is difficult to ask my partner to use a condom” was still relatively high (13.5% based on the assumption that students are supposed to know the consequences of sexual risky behaviour. It was also found that male students were 3.48 times more likely to negotiate sex than their female counterparts (OR = 3.48, 95% CI: 1.09 − 11.13 and students who were 18 years and below were more likely to negotiate sex than students above 18 years of age (OR = 2.78, 95% CI: 1.42 − 18.32. Christians are four times less likely to negotiate sex compared to non-Christians (OR = 0.219, 95% CI: 0.095 − 0.506. More than 80% of students were comfortable discussing HIV or sex and sexuality with their friends, boyfriends/girlfriends or partners but uncomfortable discussing the same issues with their parents.

  10. Dynamic behaviour and shock-induced martensite transformation in near-beta Ti-5553 alloy under high strain rate loading

    OpenAIRE

    Wang Lin; Wang Yangwei; Xu Xin; Liu Chengze

    2015-01-01

    Ti-5553 alloy is a near-beta titanium alloy with high strength and high fracture toughness. In this paper, the dynamic behaviour and shock-induced martensite phase transformation of Ti-5553 alloy with alpha/beta phases were investigated. Split Hopkinson Pressure Bar was employed to investigate the dynamic properties. Microstructure evolutions were characterized by Scanning Electronic Microscopy and Transmission Electron Microscope. The experimental results have demonstrated that Ti-5553 alloy...

  11. Wave energy plants: Control strategies for avoiding the stalling behaviour in the Wells turbine

    Energy Technology Data Exchange (ETDEWEB)

    Amundarain, Modesto; Alberdi, Mikel; Garrido, Aitor J.; Garrido, Izaskun; Maseda, Javier [Dept. of Automatic Control and Systems Engineering, EUITI Bilbao, University of the Basque Country, Plaza de la Casilla 3, 48012 Bilbao (Spain)

    2010-12-15

    This study analyzes the problem of the stalling behaviour in Wells turbines, one of the most widely used turbines in wave energy plants. For this purpose two different control strategies are presented and compared. In the first one, a rotational speed control system is employed to appropriately adapt the speed of the double-fed induction generator coupling to the turbine, according to the pressure drop entry. In the second control strategy, an airflow control regulates the power generated by the turbine generator module by means of the modulation valve avoiding the stalling behaviour. It is demonstrated that the proposed rotational speed control design adequately matches the desired relationship between the slip of the double-fed induction generator and the pressure drop input, whilst the valve control using a traditional PID controller successfully governs the flow that modulates the pressure drop across the turbine. (author)

  12. An expert system for modelling operators' behaviour in control of a steam generator

    International Nuclear Information System (INIS)

    Cacciabue, P.C.; Guida, G.; Pace, A.

    1987-01-01

    Modelling the mental processes of an operator in charge of controlling a complex industrial plant is a challenging issue currently tackled by several research projects both in the area of artificial intelligence and cognitive psychology. Progress in this field could greatly contribute not only to a deeper understanding of operator's behaviour, but also to the design of intelligent operator support systems. In this paper the authors report the preliminary results of an experimental research effort devoted to model the behaviour of a plant operator by means of Knowledge-based techniques. The main standpoints of their work is that the cognitive processes underlying operator's behaviour can be of three main different types, according to the actual situation where the operator works. In normal situations, or during training sessions, the operator is free to develop deep reasoning, using knowledge about plant structure and function and relying on the first physical principles that govern its behaviour

  13. Unhealthy weight control behaviours in adolescent girls: a process model based on self-determination theory.

    Science.gov (United States)

    Thøgersen-Ntoumani, Cecilie; Ntoumanis, Nikos; Nikitaras, Nikitas

    2010-06-01

    This study used self-determination theory (Deci, E.L., & Ryan, R.M. (2000). The 'what' and 'why' of goal pursuits: Human needs and the self-determination of behavior. Psychological Inquiry, 11, 227-268.) to examine predictors of body image concerns and unhealthy weight control behaviours in a sample of 350 Greek adolescent girls. A process model was tested which proposed that perceptions of parental autonomy support and two life goals (health and image) would predict adolescents' degree of satisfaction of their basic psychological needs. In turn, psychological need satisfaction was hypothesised to negatively predict body image concerns (i.e. drive for thinness and body dissatisfaction) and, indirectly, unhealthy weight control behaviours. The predictions of the model were largely supported indicating that parental autonomy support and adaptive life goals can indirectly impact upon the extent to which female adolescents engage in unhealthy weight control behaviours via facilitating the latter's psychological need satisfaction.

  14. A nonlinear dynamical system approach for the yielding behaviour of a viscoplastic material.

    Science.gov (United States)

    Burghelea, Teodor; Moyers-Gonzalez, Miguel; Sainudiin, Raazesh

    2017-03-08

    A nonlinear dynamical system model that approximates a microscopic Gibbs field model for the yielding of a viscoplastic material subjected to varying external stresses recently reported in R. Sainudiin, M. Moyers-Gonzalez and T. Burghelea, Soft Matter, 2015, 11(27), 5531-5545 is presented. The predictions of the model are in fair agreement with microscopic simulations and are in very good agreement with the micro-structural semi-empirical model reported in A. M. V. Putz and T. I. Burghelea, Rheol. Acta, 2009, 48, 673-689. With only two internal parameters, the nonlinear dynamical system model captures several key features of the solid-fluid transition observed in experiments: the effect of the interactions between microscopic constituents on the yield point, the abruptness of solid-fluid transition and the emergence of a hysteresis of the micro-structural states upon increasing/decreasing external forces. The scaling behaviour of the magnitude of the hysteresis with the degree of the steadiness of the flow is consistent with previous experimental observations. Finally, the practical usefulness of the approach is demonstrated by fitting a rheological data set measured with an elasto-viscoplastic material.

  15. On the characterisation of the dynamic compressive behaviour of silicon carbides subjected to isentropic compression experiments

    Directory of Open Access Journals (Sweden)

    Zinszner Jean-Luc

    2015-01-01

    Full Text Available Ceramic materials are commonly used as protective materials particularly due to their very high hardness and compressive strength. However, the microstructure of a ceramic has a great influence on its compressive strength and on its ballistic efficiency. To study the influence of microstructural parameters on the dynamic compressive behaviour of silicon carbides, isentropic compression experiments have been performed on two silicon carbide grades using a high pulsed power generator called GEPI. Contrary to plate impact experiments, the use of the GEPI device and of the lagrangian analysis allows determining the whole loading path. The two SiC grades studied present different Hugoniot elastic limit (HEL due to their different microstructures. For these materials, the experimental technique allowed evaluating the evolution of the equivalent stress during the dynamic compression. It has been observed that these two grades present a work hardening more or less pronounced after the HEL. The densification of the material seems to have more influence on the HEL than the grain size.

  16. Static and dynamic behaviours of railway prestressed concrete sleepers with longitudinal through hole

    Science.gov (United States)

    Ngamkhanong, C.; Kaewunruen, S.; Remennikov, A. M.

    2017-10-01

    As the crosstie beam in railway track systems, the prestressed concrete sleepers (or railroad ties) are principally designed in order to carry wheel loads from the rails to the ground. Their design takes into account static and dynamic loading conditions. It is evident that prestressed concrete has played a significant role as to maintain the high endurance of the sleepers under low to moderate repeated impact loads. In spite of the most common use of the prestressed concrete sleepers in railway tracks, there have always been many demands from rail engineers to improve serviceability and functionality of concrete sleepers. For example, signalling, fibre optic, equipment cables are often damaged either by ballast corners or by tamping machine. There has been a need to re-design concrete sleeper to cater cables internally so that they would not experience detrimental or harsh environments. Accordingly, this study will investigate the effects of through hole or longitudinal hole on static and dynamic behaviours of concrete sleepers under rail shock loading. The modified compression field theory for ultimate strength design of concrete sleepers will be highlighted in this study. The outcome of this study will enable the new design and calculation methods for prestressed concrete sleepers with holes and web opening that practically benefits civil, track and structural engineers in railway industry.

  17. The effect of nylon nanofibers on the dynamic behaviour and the delamination resistance of GFRP composites

    Directory of Open Access Journals (Sweden)

    Garcia Cristobal

    2018-01-01

    Full Text Available Vibrations are responsible for a considerable number of accidents in aircrafts, bridges and other civil engineering structures. Therefore, there is a need to reduce the vibrations on structures made of composite materials. Delamination is a particularly dangerous failure mode for composite materials because delaminated composites can lose up to 60% of their strength and stiffness and still remain unchanged. One of the methods to suppress vibrations and preventing delamination is to incorporate nanofibers into the composite laminates. The aim of the present work is to investigate how nylon nanofibers affect the dynamic behaviour and delamination resistance of glass fibre reinforced polymer (GFRP composites. Experiments and numerical simulations using finite element modelling (FEM analysis are used to estimate the natural frequencies, the damping ratio and inter-laminar strength in GFRP composites with and without nylon nanofibers. It is found that the natural frequencies of the nylon nano-modified composites do not change significantly as compared to the traditional composites. However, nano-modified composites demonstrated a considerable increase in damping ratio and inter-laminar shear strength due to the incorporation of nylon nanofibers. This work contributes to the knowledge about the mechanical and dynamic properties of glass fibre reinforced polymer (GFRP composites with nylon nanofibers.

  18. Remote control of SMM behaviour via DTE ligands.

    Science.gov (United States)

    Cosquer, Goulven; Breedlove, Brian K; Yamashita, Masahiro

    2015-02-21

    Chemists and physicists are continuously working to understand the mechanisms controlling molecular magnetism, especially single-molecule magnetism, to improve the magnetic properties, such as the blocking temperature. With the current research focused on preparing molecular devices, methods to control the components of the devices are necessary. Extensive research has shown that stimuli, such as light, electric current, etc., can be used to change the properties of the molecules making up the devices. Bis(carboxylato)dithienylethene (DTE) derivatives can be photo-isomerized between open and closed forms, i.e., unconjugated and π-conjugated forms, and because of the carboxylate groups, it can be used to link 3d and/or 4f metal ions. Herein the use of DTE ligands to remotely control the magnetic properties of single-molecule magnets is discussed.

  19. Modelling sediment dynamics due to hillslope-river interactions : incorporating fluvial behaviour in landscape evolution model LAPSUS

    NARCIS (Netherlands)

    Baartman, Jantiene E. M.; van Gorp, Wouter; Temme, Arnaud J. A. M.; Schoorl, Jeroen M.

    Landscape evolution models (LEMs) simulate the three-dimensional development of landscapes over time. Different LEMs have different foci, e.g. erosional behaviour, river dynamics, the fluvial domain, hillslopes or a combination. LEM LAPSUS is a relatively simple cellular model operating on

  20. Controllable behaviours of rogue wave triplets in the nonautonomous nonlinear and dispersive system

    International Nuclear Information System (INIS)

    Dai Chaoqing; Tian Qing; Zhu Shiqun

    2012-01-01

    A similarity transformation connecting the variable coefficient nonlinear Schrödinger equation with the standard nonlinear Schrödinger equation is constructed. The self-similar rogue wave triplet solutions (rational solutions) are analytically obtained for the nonautonomous nonlinear and dispersive system. The controllable behaviours of rogue wave triplets in two typical soliton management systems are discussed. In the exponential dispersion decreasing fibre, three kinds of rogue wave triplets with controllable behaviours are analysed. In the periodic distributed system, the rogue wave triplets recur periodically in the form of a cluster. (paper)

  1. A Higher Harmonic Optimal Controller to Optimise Rotorcraft Aeromechanical Behaviour

    Science.gov (United States)

    Leyland, Jane Anne

    1996-01-01

    Three methods to optimize rotorcraft aeromechanical behavior for those cases where the rotorcraft plant can be adequately represented by a linear model system matrix were identified and implemented in a stand-alone code. These methods determine the optimal control vector which minimizes the vibration metric subject to constraints at discrete time points, and differ from the commonly used non-optimal constraint penalty methods such as those employed by conventional controllers in that the constraints are handled as actual constraints to an optimization problem rather than as just additional terms in the performance index. The first method is to use a Non-linear Programming algorithm to solve the problem directly. The second method is to solve the full set of non-linear equations which define the necessary conditions for optimality. The third method is to solve each of the possible reduced sets of equations defining the necessary conditions for optimality when the constraints are pre-selected to be either active or inactive, and then to simply select the best solution. The effects of maneuvers and aeroelasticity on the systems matrix are modelled by using a pseudo-random pseudo-row-dependency scheme to define the systems matrix. Cases run to date indicate that the first method of solution is reliable, robust, and easiest to use, and that it was superior to the conventional controllers which were considered.

  2. Biomolecular Modeling in a Process Dynamics and Control Course

    Science.gov (United States)

    Gray, Jeffrey J.

    2006-01-01

    I present modifications to the traditional course entitled, "Process dynamics and control," which I renamed "Modeling, dynamics, and control of chemical and biological processes." Additions include the central dogma of biology, pharmacokinetic systems, population balances, control of gene transcription, and large­-scale…

  3. Molecular dynamics study of vacancy-like defects in a model glass : static behaviour

    Science.gov (United States)

    Delaye, J. M.; Limoge, Y.

    1993-10-01

    The possibility of defining vacancy-like defects in a Lennard-Jones glass is searched for in a systematic manner. Considering different relaxation levels of the same system, as well as different external pressures, we use a Molecular Dynamics simulation method, to study at constant volume or external pressure, the relaxation of a “piece” of glass, after the sudden removal of an atom. Three typical kinds of behaviour can be observed: the persistence of the empty volume left by the missing atom, its migration by clearly identifiable atomic jumps and the dissipation “on the spot”. A careful analysis of the probabilities of these three kinds of behaviour shows that a meaningful definition of vacancy-like defects can be given in a Lennard-Jones glass. Dans cet article, nous nous penchons de façon systématique sur la possibilité de définir des défauts de type lacunaire dans un verre de Lennard-Jones, à différents niveaux de relaxation et de pression, par une méthode de simulation numérique en dynamique moléculaire à volume ou à pression constants. Le défaut est créé en supprimant un atome et en suivant la réponse du système. Nous observons trois comportements typiques : la persistance sur place du “trou” laissé par l'atome supprimé, sa migration par des sauts atomiques clairement identifiés et enfin sa dissipation sur place. Une analyse détaillée de ces trois comportements montre qu'il est possible dans un verre de Lennard-Jones de définir des défauts de type lacunaire.

  4. Isothermal and dynamic oxidation behaviour of Mo-W doped carbon-based coating

    Science.gov (United States)

    Mandal, Paranjayee; Ehiasarian, Arutiun P.; Hovsepian, Papken Eh.

    2015-10-01

    The oxidation behaviour of Mo-W doped carbon-based coating (Mo-W-C) is investigated in elevated temperature (400-1000 °C). Strong metallurgical bond between Mo-W-C coating and substrate prevents any sort of delamination during heat-treatment. Isothermal oxidation tests show initial growth of metal oxides at 500 °C, however graphitic nature of the as-deposited coating is preserved. The oxidation progresses with further rise in temperature and the substrate is eventually exposed at 700 °C. The performance of Mo-W-C coating is compared with a state-of-the-art DLC(Cr/Cr-WC/W:C-H/a:C-H) coating, which shows preliminary oxidation at 400 °C and local delamination of the coating at 500 °C leading to substrate exposure. The graphitisation starts at 400 °C and the diamond-like structure is completely converted into the graphite-like structure at 500 °C. Dynamic oxidation behaviour of both the coatings is investigated using Thermo-gravimetric analysis carried out with a slow heating rate of 1 °C/min from ambient temperature to 1000 °C. Mo-W-C coating resists oxidation up to ˜800 °C whereas delamination of DLC(Cr/Cr-WC/W:C-H/a:C-H) coating is observed beyond ˜380 °C. In summary, Mo-W-C coating provides improved oxidation resistance at elevated temperature compared to DLC(Cr/Cr-WC/W:C-H/a:C-H) coating.

  5. The effects of temperature and strain rate on the dynamic flow behaviour of different steels

    International Nuclear Information System (INIS)

    Lee, W.-S.; Liu, C.-Y.

    2006-01-01

    A compressive type split-Hopkinson pressure bar is utilized to compare the impact plastic behaviour of three steels with different levels of carbon content. S15C low carbon steel, S50C medium alloy heat treatable steel (abbreviated hereafter to medium carbon steel) and SKS93 tool steel with a high carbon and low alloy content (abbreviated hereafter to high carbon steel) are tested under strain rates ranging from 1.1 x 10 3 s -1 to 5.5 x 10 3 s -1 and temperatures ranging from 25 to 800 deg. C. The effects of the carbon content, strain rate and temperature on the mechanical responses of the three steels are evaluated. The microstructures of the impacted specimens are studied using a transmission electron microscope (TEM). It is found that an increased carbon content enhances the dynamic flow resistance of the three steels. Additionally, the flow stress increases with strain and strain rate in every case. A thermal softening effect is identified in the plastic behaviour of the three steels. The activation energy, ΔG * , varies as a function of the strain rate and temperature, but is apparently insensitive to the carbon content level. The present study identifies maximum ΔG * values of 58 kJ/mol for the S15C low carbon steel, 54.9 kJ/mol for the S50C medium carbon steel, and 56.4 kJ/mol for the SKS93 high carbon steel. A Zerilli-Armstrong BCC constitutive model with appropriate coefficients is applied to describe the high strain rate plastic behaviours of the S15C, S50C and SKS93 steels. The errors between the calculated stress and the measured stress are found to be less than 5%. The microstructural observations reveal that the dislocation density and the degree of dislocation tangling increase with increasing strain rate in all three steels. Additionally, the TEM observations indicate that a higher strain rate reduces the size of the dislocation cells. The annihilation of dislocations occurs more readily at elevated temperatures. The square root of the dislocation

  6. System dynamic model and charging control of lead-acid battery for stand-alone solar PV system

    KAUST Repository

    Huang, B.J.; Hsu, P.C.; Wu, M.S.; Ho, P.Y.

    2010-01-01

    . This will reduce the storage energy capacity and reduce the service time in electricity supply. The design of charging control system however requires a good understanding of the system dynamic behaviour of the battery first. In the present study, a first

  7. Fixed-Wing UAVs Flock Control through Cohesion and Repulsion Behaviours Combined with a Leadership

    Directory of Open Access Journals (Sweden)

    Cezary Kownacki

    2016-02-01

    Full Text Available The aim of this paper is to present a novel approach to swarm control of small fixed-wing UAVs, which combines only two flocking behaviours with a leadership feature. In the presented approach, two fundamental rules of Reynolds flocking are applied, i.e., cohesion and repulsion, as the base of a decentralized control of self-organization of the flock. These rules are combined with a leadership feature, which is responsible for a global behaviour of guidance, as in the case of animals. Such a bio-inspired combination allows the achievement of a coherent collective flight of a flock of fixed-wing UAVs without applying formal behaviours of migration and alignment. This highly simplifies an implementation of the algorithm. The presented results include both numerical simulations and experimental flights, which validate the hardware implementation of the approach.

  8. Steering the dynamics within reduced space through quantum learning control

    International Nuclear Information System (INIS)

    Kim, Young Sik

    2003-01-01

    In quantum dynamics of many-body systems, to identify the Hamiltonian becomes more difficult very rapidly as the number of degrees of freedom increases. In order to simplify the dynamics and to deduce dynamically relevant Hamiltonian information, it is desirable to control the dynamics to lie within a reduced space. With a judicious choice for the cost functional, the closed loop optimal control experiments can be manipulated efficiently to steer the dynamics to lie within a subspace of the system eigenstates without requiring any prior detailed knowledge about the system Hamiltonian. The procedure is simulated for optimally controlled population transfer experiments in the system of two degrees of freedom. To show the feasibility of steering the dynamics to lie in a specified subspace, the learning algorithms guiding the dynamics are presented along with frequency filtering. The results demonstrate that the optimal control fields derive the system to the desired target state through the desired subspace

  9. Impulse control disorder related behaviours during long-term rotigotine treatment: a post hoc analysis.

    Science.gov (United States)

    Antonini, A; Chaudhuri, K R; Boroojerdi, B; Asgharnejad, M; Bauer, L; Grieger, F; Weintraub, D

    2016-10-01

    Dopamine agonists in Parkinson's disease (PD) are associated with impulse control disorders (ICDs) and other compulsive behaviours (together called ICD behaviours). The frequency of ICD behaviours reported as adverse events (AEs) in long-term studies of rotigotine transdermal patch in PD was evaluated. This was a post hoc analysis of six open-label extension studies up to 6 years in duration. Analyses included patients treated with rotigotine for at least 6 months and administered the modified Minnesota Impulse Disorders Interview. ICD behaviours reported as AEs were identified and categorized. For 786 patients, the mean (±SD) exposure to rotigotine was 49.4 ± 17.6 months. 71 (9.0%) patients reported 106 ICD AEs cumulatively. Occurrence was similar across categories: 2.5% patients reported 'compulsive sexual behaviour', 2.3% 'buying disorder', 2.0% 'compulsive gambling', 1.7% 'compulsive eating' and 1.7% 'punding behaviour'. Examining at 6-month intervals, the incidence was relatively low during the first 30 months; it was higher over the next 30 months, peaking in the 54-60-month period. No ICD AEs were serious, and 97% were mild or moderate in intensity. Study discontinuation occurred in seven (9.9%) patients with ICD AEs; these then resolved in five patients. Dose reduction occurred for 23 AEs, with the majority (73.9%) resolving. In this analysis of >750 patients with PD treated with rotigotine, the frequency of ICD behaviour AEs was 9.0%, with a specific incidence timeline observed. Active surveillance as duration of treatment increases may help early identification and management; once ICD behaviours are present rotigotine dose reduction may be considered. © 2016 The Authors. European Journal of Neurology published by John Wiley & Sons Ltd on behalf of European Academy of Neurology.

  10. Dynamic behaviour of magneto-acoustic emission in a grain-oriented steel

    Czech Academy of Sciences Publication Activity Database

    Stupakov, Alexandr; Perevertov, Oleksiy; Landa, Michal

    2017-01-01

    Roč. 426, Mar (2017), s. 685-690 ISSN 0304-8853 R&D Projects: GA ČR GB14-36566G; GA ČR GA13-18993S Institutional support: RVO:68378271 ; RVO:61388998 Keywords : magneto-acoustic emission * magnetization dynamics * Barkhausen noise * surface field measurement * magnetization waveform control Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 2.630, year: 2016

  11. Further steps in the modeling of behavioural crowd dynamics, good news for safe handling. Comment on "Human behaviours in evacuation crowd dynamics: From modelling to "big data" toward crisis management" by Nicola Bellomo et al.

    Science.gov (United States)

    Knopoff, Damián A.

    2016-09-01

    The recent review paper [4] constitutes a valuable contribution on the understanding, modeling and simulation of crowd dynamics in extreme situations. It provides a very comprehensive revision about the complexity features of the system under consideration, scaling and the consequent justification of the used methods. In particular, macro and microscopic models have so far been used to model crowd dynamics [9] and authors appropriately explain that working at the mesoscale is a good choice to deal with the heterogeneous behaviour of walkers as well as with the difficulty of their deterministic identification. In this way, methods based on the kinetic theory and statistical dynamics are employed, more precisely the so-called kinetic theory for active particles [7]. This approach has successfully been applied in the modeling of several complex dynamics, with recent applications to learning [2,8] that constitutes the key to understand communication and is of great importance in social dynamics and behavioral sciences.

  12. Control Framework for Dexterous Manipulation Using Dynamic Visual Servoing and Tactile Sensors’ Feedback

    Directory of Open Access Journals (Sweden)

    Carlos A. Jara

    2014-01-01

    Full Text Available Tactile sensors play an important role in robotics manipulation to perform dexterous and complex tasks. This paper presents a novel control framework to perform dexterous manipulation with multi-fingered robotic hands using feedback data from tactile and visual sensors. This control framework permits the definition of new visual controllers which allow the path tracking of the object motion taking into account both the dynamics model of the robot hand and the grasping force of the fingertips under a hybrid control scheme. In addition, the proposed general method employs optimal control to obtain the desired behaviour in the joint space of the fingers based on an indicated cost function which determines how the control effort is distributed over the joints of the robotic hand. Finally, authors show experimental verifications on a real robotic manipulation system for some of the controllers derived from the control framework.

  13. Numerical Prediction of Hydromechanical Behaviour of Controllable Pitch Propeller

    Directory of Open Access Journals (Sweden)

    Saman Tarbiat

    2014-01-01

    Full Text Available The research described in this paper was carried out to predict hydrodynamic and frictional forces of controllable pitch propeller (CPP that bring about fretting problems in a blade bearing. The governing equations are Reynolds-averaged Navier-Stokes (RANS and are solved by OpenFOAM solver for hydrodynamic forces behind the ship’s wake. Frictional forces are calculated by practical mechanical formulae. Different advance velocities with constant rotational speed for blades are used to achieve hydrodynamic coefficients in open water and the wake behind the propeller. Results are compared at four different pitches. Detailed numerical results of 3D modelling of the propeller, hydrodynamic characteristics, and probability of the fretting motion in the propeller are presented. Results show that the probability of the fretting movement is related to the pitch.

  14. Compressible dynamic stall vorticity flux control using a dynamic ...

    Indian Academy of Sciences (India)

    systems, such as a wind turbine, are prevented from ever entering dynamic stall, essentially disregarding potential ... future generations of such systems, an overwhelming need has developed to avail this benefit safely. ... approach must diffuse the vorticity prior to its coalescence, but keep the vorticity over the airfoil up to ...

  15. Postural control and head stability during natural gaze behaviour in 6- to 12-year-old children.

    Science.gov (United States)

    Schärli, A M; van de Langenberg, R; Murer, K; Müller, R M

    2013-06-01

    We investigated how the influence of natural exploratory gaze behaviour on postural control develops from childhood into adulthood. In a cross-sectional design, we compared four age groups: 6-, 9-, 12-year-olds and young adults. Two experimental trials were performed: quiet stance with a fixed gaze (fixed) and quiet stance with natural exploratory gaze behaviour (exploratory). The latter was elicited by having participants watch an animated short film on a large screen in front of them. 3D head rotations in space and centre of pressure (COP) excursions on the ground plane were measured. Across conditions, both head rotation and COP displacement decreased with increasing age. Head movement was greater in the exploratory condition in all age groups. In all children-but not in adults-COP displacement was markedly greater in the exploratory condition. Bivariate correlations across groups showed highly significant positive correlations between COP displacement in ML direction and head rotation in yaw, roll, and pitch in both conditions. The regularity of COP displacements did not show a clear developmental trend, which indicates that COP dynamics were qualitatively similar across age groups. Together, the results suggest that the contribution of head movement to eye-head saccades decreases with age and that head instability-in part resulting from such gaze-related head movements-is an important limiting factor in children's postural control. The lack of head stabilisation might particularly affect children in everyday activities in which both postural control and visual exploration are required.

  16. Stove checking behaviour in people with OCD vs. anxious controls.

    Science.gov (United States)

    Bucarelli, Bianca; Purdon, Christine

    2016-12-01

    A growing body of research suggests that the repetition of an action degrades memory for that action, as well as confidence that is has been done correctly. This has important implications for understanding the compulsive repetition of actions characteristic of obsessive compulsive disorder (OCD). At this time, though, much of the research has been conducted on analogue or nonclinical OCD samples in comparison to healthy controls and often using virtual, as opposed to actual, threat stimuli. Furthermore, although it has been argued that people with OCD are overly attentive to threat stimuli, the research on actual attention to threat is scant. People with a principal diagnosis of OCD (n = 30) and people with a clinically significant diagnosis of an anxiety disorder, but no OCD (n = 18) completed measures of memory confidence and responsibility and then underwent a stove-checking task in a functioning kitchen while wearing a portable eye tracking device. Pre- and post-task ratings of harm and responsibility were taken, along with post-task ratings of memory and certainty. People with OCD did not exhibit poorer memory confidence than the anxious control (AC) group, but did report greater trait and state responsibility for harm. The OCD group checked longer than did the AC group and check duration predicted post-task ratings of harm, but to the same extent in both groups. People with OCD attended to threat items less than did the AC group. Greater visual attention to the stove during the checking period was associated with greater post-task ratings of responsibility and harm and with less certainty in and memory for the check - but only for the AC group. The sample size was modest, women were over-represented and problems with the eye tracking device reduced the amount of reliable data available for analysis. Compulsions are complex actions that are mediated by many trait, state and contextual factors. People with OCD may be able to circumvent self

  17. Behavioural effects of advanced cruise control use : a meta-analytic approach.

    NARCIS (Netherlands)

    Dragutinovic, N. Brookhuis, K.A. Hagenzieker, M.P. & Marchau, V.A.W.J.

    2006-01-01

    In this study, a meta-analytic approach was used to analyse effects of Advanced Cruise Control (ACC) on driving behaviour reported in seven driving simulator studies. The effects of ACC on three consistent outcome measures, namely, driving speed, headway and driver workload have been analysed. The

  18. Internet cognitive behavioural treatment for obsessive compulsive disorder : A randomised controlled trial

    NARCIS (Netherlands)

    Mahoney, Alison E J; Mackenzie, Anna; Williams, Alishia D; Smith, Jessica; Andrews, Gavin

    2014-01-01

    Internet-based cognitive behaviour therapy (iCBT) is becoming increasing accepted as an efficacious and effective treatment for the anxiety and depressive disorders. However few studies have examined the efficacy of iCBT for obsessive compulsive disorder (OCD). This randomised controlled trial

  19. Behavioural Comorbidity in Tanzanian Children with Epilepsy: A Community-Based Case-Control Study

    Science.gov (United States)

    Burton, Kathryn; Rogathe, Jane; Hunter, Ewan; Burton, Matthew; Swai, Mark; Todd, Jim; Neville, Brian; Walker, Richard; Newton, Charles

    2011-01-01

    Aim: The aim of this study was to define the prevalence of and risk factors for behavioural disorders in children with epilepsy from a rural district of Tanzania by conducting a community-based case-control study. Method: One hundred and twelve children aged 6 to 14 years (55 males, 57 females; median age 12y) with active epilepsy (at least two…

  20. The impact of maternal control on children's anxious cognitions, behaviours and affect: an experimental study.

    Science.gov (United States)

    Thirlwall, Kerstin; Creswell, Cathy

    2010-10-01

    Controlling parenting is associated with child anxiety however the direction of effects remains unclear. The present study implemented a Latin-square experimental design to assess the impact of parental control on children's anxious affect, cognitions and behaviour. A non-clinical sample of 24 mothers of children aged 4-5 years were trained to engage in (a) controlling and (b) autonomy-granting behaviours in interaction with their child during the preparation of a speech. When mothers engaged in controlling parenting behaviours, children made more negative predictions about their performance prior to delivering their speech and reported feeling less happy about the task, and this was moderated by child trait anxiety. In addition, children with higher trait anxiety displayed a significant increase in observed child anxiety in the controlling condition. The pattern of results was maintained when differences in mothers' levels of negativity and habitual levels of control were accounted for. These findings are consistent with theories that suggest that controlling parenting is a risk factor in the development of childhood anxiety. Copyright 2010 Elsevier Ltd. All rights reserved.

  1. Dynamic mechanical behaviour of nanoparticle loaded biodegradable PVA films for vaginal drug delivery.

    Science.gov (United States)

    Traore, Yannick L; Fumakia, Miral; Gu, Jijin; Ho, Emmanuel A

    2018-03-01

    In this study, we investigated the viscoelastic and mechanical behaviour of polyvinyl alcohol films formulated along with carrageenan, plasticizing agents (polyethylene glycol and glycerol), and when loaded with nanoparticles as a model for potential applications as microbicides. The storage modulus, loss modulus and glass transition temperature were determined using a dynamic mechanical analyzer. Films fabricated from 2% to 5% polyvinyl alcohol containing 3 mg or 5 mg of fluorescently labeled nanoparticles were evaluated. The storage modulus and loss modulus values of blank films were shown to be higher than the nanoparticle-loaded films. Glass transition temperature determined using the storage modulus, and loss modulus was between 40-50℃ and 35-40℃, respectively. The tensile properties evaluated showed that 2% polyvinyl alcohol films were more elastic but less resistant to breaking compared to 5% polyvinyl alcohol films (2% films break around 1 N load and 5% films break around 7 N load). To our knowledge, this is the first study to evaluate the influence of nanoparticle and film composition on the physico-mechanical properties of polymeric films for vaginal drug delivery.

  2. Digital signal processing for velocity measurements in dynamical material's behaviour studies

    International Nuclear Information System (INIS)

    Devlaminck, Julien; Luc, Jerome; Chanal, Pierre-Yves

    2014-01-01

    In this work, we describe different configurations of optical fiber interferometers (types Michelson and Mach-Zehnder) used to measure velocities during dynamical material's behaviour studies. We detail the algorithms of processing developed and optimized to improve the performance of these interferometers especially in terms of time and frequency resolutions. Three methods of analysis of interferometric signals were studied. For Michelson interferometers, the time-frequency analysis of signals by Short-Time Fourier Transform (STFT) is compared to a time-frequency analysis by Continuous Wavelet Transform (CWT). The results have shown that the CWT was more suitable than the STFT for signals with low signal-to-noise, and low velocity and high acceleration areas. For Mach- Zehnder interferometers, the measurement is carried out by analyzing the phase shift between three interferometric signals (Triature processing). These three methods of digital signal processing were evaluated, their measurement uncertainties estimated, and their restrictions or operational limitations specified from experimental results performed on a pulsed power machine. (authors)

  3. Modelling Dynamic Behaviour and Spall Failure of Aluminium Alloy AA7010

    Science.gov (United States)

    Ma'at, N.; Nor, M. K. Mohd; Ismail, A. E.; Kamarudin, K. A.; Jamian, S.; Ibrahim, M. N.; Awang, M. K.

    2017-10-01

    A finite strain constitutive model to predict the dynamic deformation behaviour of Aluminium Alloy 7010 including shockwaves and spall failure is developed in this work. The important feature of this newly hyperelastic-plastic constitutive formulation is a new Mandel stress tensor formulated using new generalized orthotropic pressure. This tensor is combined with a shock equation of state (EOS) and Grady spall failure. The Hill’s yield criterion is adopted to characterize plastic orthotropy by means of the evolving structural tensors that is defined in the isoclinic configuration. This material model was developed and integration into elastic and plastic parts. The elastic anisotropy is taken into account through the newly stress tensor decomposition of a generalized orthotropic pressure. Plastic anisotropy is considered through yield surface and an isotropic hardening defined in a unique alignment of deviatoric plane within the stress space. To test its ability to describe shockwave propagation and spall failure, the new material model was implemented into the LLNL-DYNA3D code of UTHM’s. The capability of this newly constitutive model were compared against published experimental data of Plate Impact Test at 234m/s, 450m/s and 895m/s impact velocities. A good agreement is obtained between experimental and simulation in each test.

  4. Behaviour and control of radionuclides in the environment: present state of knowledge and future needs

    International Nuclear Information System (INIS)

    Myttenaere, C.

    1983-01-01

    The Radiation Protection Programme of the European Communities is discussed in the context of the behaviour and control of radionuclides in the environment with reference to the aims of the programme, the results of current research activities and requirements for future studies. The summarised results of the radioecological research activities for 1976 - 1980 include the behaviour of α-emitters (Pu, Am, Cm), 99 Tc, 137 Cs, 144 Ce, 106 Ru and 125 Sb in marine environments; atmospheric dispersion of radionuclides; and the transport of radionuclides in components of freshwater and terrestrial ecosystems. (U.K.)

  5. Dynamic cost control information system for nuclear power plant construction

    International Nuclear Information System (INIS)

    Wang Yongqing; Liu Wei

    1998-01-01

    The authors first introduce the cost control functions of some overseas popular project management software at present and the specific ways of cost control of nuclear power plant construction in China. Then the authors stress the necessity of cost and schedule control integration and present the concept of dynamic cost control, the design scheme of dynamic cost control information system and the data structure modeling. Based on the above, the authors can develop the system which has the functions of dynamic estimate, cash flow management and cost optimization for nuclear engineering

  6. Survey of occupant behaviour and control of indoor environment in Danish dwellings

    DEFF Research Database (Denmark)

    Andersen, Rune Vinther; Toftum, Jørn; Andersen, Klaus Kaae

    2009-01-01

    separately by means of multiple logistic regression in order to quantify factors influencing occupants’ behaviour. The window opening behaviour was strongly related to the outdoor temperature. The perception of the environment and factors concerning the dwelling also impacted the window opening behaviour......Repeated surveys of occupant control of the indoor environment were carried out in Danish dwellings from September to October 2006 and again from February to March 2007. The summer survey comprised 933 respondents and the winter survey 636 respondents. The surveys were carried out by sending out....... The proportion of dwellings with the heating turned on was strongly related to the outdoor temperature and the presence of a wood burning stove. The solar radiation, dwelling ownership conditions and the perception of the indoor environment also affected the use of heating. The results of the statistical...

  7. Effectiveness of telephone-assisted parent-administered behavioural family intervention for preschool children with externalizing problem behaviour: a randomized controlled trial.

    Science.gov (United States)

    Kierfeld, Frauke; Ise, Elena; Hanisch, Charlotte; Görtz-Dorten, Anja; Döpfner, Manfred

    2013-09-01

    Externalizing problem behaviour is one of the most common childhood disorders. Parent training is an effective treatment for these children and there is growing interest in the effects of parent-administered interventions with minimal therapist contact. This randomized controlled study examined the efficacy of a telephone-assisted parent-administered behavioural intervention (bibliotherapy) in families with preschool children with externalizing problem behaviour. Families were randomly assigned to a treatment group (n = 26) and an untreated waitlist control group (n = 22). The intervention comprised the reading of an 11 chapter self-help book and 11 weekly telephone consultations. Compared to the control group, the treatment group demonstrated significant decreases in parent-reported externalizing and internalizing child problem behaviour and dysfunctional parenting practices. Moreover, treated parents reported less parenting-related strains and decreases in parental depression, anxiety, and stress. The results suggest that telephone-assisted self-administered parent training is an effective alternative to more intensive forms of behavioural family intervention for preschool children with externalizing problem behaviour.

  8. The dynamical integrity concept for interpreting/ predicting experimental behaviour: from macro- to nano-mechanics.

    Science.gov (United States)

    Lenci, Stefano; Rega, Giuseppe; Ruzziconi, Laura

    2013-06-28

    The dynamical integrity, a new concept proposed by J.M.T. Thompson, and developed by the authors, is used to interpret experimental results. After reviewing the main issues involved in this analysis, including the proposal of a new integrity measure able to capture in an easy way the safe part of basins, attention is dedicated to two experiments, a rotating pendulum and a micro-electro-mechanical system, where the theoretical predictions are not fulfilled. These mechanical systems, the former at the macro-scale and the latter at the micro-scale, permit a comparative analysis of different mechanical and dynamical behaviours. The fact that in both cases the dynamical integrity permits one to justify the difference between experimental and theoretical results, which is the main achievement of this paper, shows the effectiveness of this new approach and suggests its use in practical situations. The men of experiment are like the ant, they only collect and use; the reasoners resemble spiders, who make cobwebs out of their own substance. But the bee takes the middle course: it gathers its material from the flowers of the garden and field, but transforms and digests it by a power of its own. Not unlike this is the true business of philosophy (science); for it neither relies solely or chiefly on the powers of the mind, nor does it take the matter which it gathers from natural history and mechanical experiments and lay up in the memory whole, as it finds it, but lays it up in the understanding altered and digested. Therefore, from a closer and purer league between these two faculties, the experimental and the rational (such as has never been made), much may be hoped. (Francis Bacon 1561-1626) But are we sure of our observational facts? Scientific men are rather fond of saying pontifically that one ought to be quite sure of one's observational facts before embarking on theory. Fortunately those who give this advice do not practice what they preach. Observation and theory get

  9. Considering behaviour to ensure the success of a disease control strategy.

    Science.gov (United States)

    McQuaid, Christopher Finn; Gilligan, Christopher Aidan; van den Bosch, Frank

    2017-12-01

    The success or failure of a disease control strategy can be significantly affected by the behaviour of individual agents involved, influencing the effectiveness of disease control, its cost and sustainability. This behaviour has rarely been considered in agricultural systems, where there is significant opportunity for impact. Efforts to increase the adoption of control while decreasing oscillations in adoption and yield, particularly through the administration of subsidies, could increase the effectiveness of interventions. We study individual behaviour for the deployment of clean seed systems to control cassava brown streak disease in East Africa, noting that high disease pressure is important to stimulate grower demand of the control strategy. We show that it is not necessary to invest heavily in formal promotional or educational campaigns, as word-of-mouth is often sufficient to endorse the system. At the same time, for improved planting material to have an impact on increasing yields, it needs to be of a sufficient standard to restrict epidemic spread significantly. Finally, even a simple subsidy of clean planting material may be effective in disease control, as well as reducing oscillations in adoption, as long as it reaches a range of different users every season.

  10. Stimulus control and affect in dietary behaviours. An intensive longitudinal study.

    Science.gov (United States)

    Schüz, Benjamin; Bower, Jodie; Ferguson, Stuart G

    2015-04-01

    Dietary behaviours are substantially influenced by environmental and internal stimuli, such as mood, social situation, and food availability. However, little is known about the role of stimulus control for eating in non-clinical populations, and no studies so far have looked at eating and drinking behaviour simultaneously. 53 individuals from the general population took part in an intensive longitudinal study with repeated, real-time assessments of eating and drinking using Ecological Momentary Assessment. Eating was assessed as main meals and snacks, drinks assessments were separated along alcoholic and non-alcoholic drinks. Situational and internal stimuli were assessed during both eating and drinking events, and during randomly selected non-eating occasions. Hierarchical multinomial logistic random effects models were used to analyse data, comparing dietary events to non-eating occasions. Several situational and affective antecedents of dietary behaviours could be identified. Meals were significantly associated with having food available and observing others eat. Snacking was associated with negative affect, having food available, and observing others eat. Engaging in activities and being with others decreased the likelihood of eating behaviours. Non-alcoholic drinks were associated with observing others eat, and less activities and company. Alcoholic drinks were associated with less negative affect and arousal, and with observing others eat. RESULTS support the role of stimulus control in dietary behaviours, with support for both internal and external, in particular availability and social stimuli. The findings for negative affect support the idea of comfort eating, and results point to the formation of eating habits via cue-behaviour associations. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Two inhibitory control training interventions designed to improve eating behaviour and determine mechanisms of change.

    Science.gov (United States)

    Allom, Vanessa; Mullan, Barbara

    2015-06-01

    Inhibitory control training has been shown to influence eating behaviour in the laboratory; however, the reliability of these effects is not yet established outside the laboratory, nor are the mechanisms responsible for change in behaviour. Two online Stop-Signal Task training interventions were conducted to address these points. In Study 1, 72 participants completed baseline and follow-up measures of inhibitory control, self-regulatory depletion, fat intake and body-mass index. Participants were randomly assigned to complete one of three Stop-Signal Tasks daily for ten days: food-specific inhibition--inhibition in response to unhealthy food stimuli only, general inhibition--inhibition was not contingent on type of stimuli, and control--no inhibition. While fat intake did not decrease, body-mass index decreased in the food-specific condition and change in this outcome was mediated by changes in vulnerability to depletion. In Study 2, the reliability and longevity of these effects were tested by replicating the intervention with a third measurement time-point. Seventy participants completed baseline, post-intervention and follow-up measures. While inhibitory control and vulnerability to depletion improved in both training conditions post-intervention, eating behaviour and body-mass index did not. Further, improvements in self-regulatory outcomes were not maintained at follow-up. It appears that while the training paradigm employed in the current studies may improve self-regulatory outcomes, it may not necessarily improve health outcomes. It is suggested that this may be due to the task parameters, and that a training paradigm that utilises a higher proportion of stop-signals may be necessary to change behaviour. In addition, improvements in self-regulation do not appear to persist over time. These findings further current conceptualisations of the nature of self-regulation and have implications for the efficacy of online interventions designed to improve eating

  12. Anomalous thermodynamic behaviour of novel compounds: inelastic neutron scattering and lattice dynamics studies

    International Nuclear Information System (INIS)

    Mittal, R.

    2014-01-01

    The understanding of the thermodynamic properties of solids has important applications in diverse areas like condensed matter physics, materials science, mineralogy, geophysics, etc. We have been extensively investigating anomalous thermodynamic properties of compounds using the techniques of inelastic neutron scattering and lattice dynamics. We would present some of the results from our recent studies. Studies of materials exhibiting anomalous thermal expansion are of interest due to their fundamental scientific importance and potential applications in ceramic, optical and electronic industry etc. We have studied the thermodynamic properties of negative thermal expansion (NTE) compounds ZrW 2 O 8 , HfW 2 O 8 , ZrMo 2 O 8 , ZrV 2 O 7 , HfV 2 O 7 , Zn(CN) 2 , Cu 2 O, Ag 2 O, Ag 3 Co(CN) 6 and Ag 3 Fe(CN) 6 . Our calculations predicted that large softening of the phonon spectrum involving librational and translational modes below 10 MeV would be responsible for anomalous thermal expansion behaviour. High pressure inelastic neutron scattering experiments carried by us on cubic ZrW 2 O 8 , ZrMo 2 O 8 and Zn(CN) 2 confirmed the phonon softening. Our studies indicate that unusual phonon softening of low energy modes is able to account for the thermal expansion behaviour in these compounds. Superionic conduction in fluorite-structured (anti-fluorite, Li 2 O) oxides (MO 2 , M= U, Th) have applications in energy storage, conversion and nuclear industry. The possible role of phonon in initiation of diffusion has been studied in Li 2 O. We found that in the superionic regime lithium atoms may exhibit macroscopic movement along (100) direction. The microscopic modeling or simulation is found to play a pivotal role in understanding the conduction processes at high temperatures in Li 2 O. We have also studied zircon structured compounds MSiO 4 (M=Zr, Hf, Th, U), RPO 4 , (R=rare earth atom). The compounds are known to transform to the scheelite (body centered tetragonal, I4 1 /a

  13. Simulation and Experimental Investigation of Structural Dynamic Frequency Characteristics Control

    Directory of Open Access Journals (Sweden)

    Bing Li

    2012-04-01

    Full Text Available In general, mechanical equipment such as cars, airplanes, and machine tools all operate with constant frequency characteristics. These constant working characteristics should be controlled if the dynamic performance of the equipment demands improvement or the dynamic characteristics is intended to change with different working conditions. Active control is a stable and beneficial method for this, but current active control methods mainly focus on vibration control for reducing the vibration amplitudes in the time domain or frequency domain. In this paper, a new method of dynamic frequency characteristics active control (DFCAC is presented for a flat plate, which can not only accomplish vibration control but also arbitrarily change the dynamic characteristics of the equipment. The proposed DFCAC algorithm is based on a neural network including two parts of the identification implement and the controller. The effectiveness of the DFCAC method is verified by several simulation and experiments, which provide desirable results.

  14. Study of the dynamic behaviour of the reactor Rapsodie; Etude du comportement dynamique de la pile rapsodie

    Energy Technology Data Exchange (ETDEWEB)

    Abdon, R; Chaigne, M [Commissariat a l' Energie Atomique, Cadarache (France). Centre d' Etudes Nucleaires

    1964-07-01

    It is known that fast neutron breeder reactors pose new problems in the fields of mechanics and heat technology, as well as in respect to their dynamic behaviour and safety. The reactor RAPSODIE has been the object of numerous dynamic studies on analogue and digital computers for two types of fuel (metal and oxide). After elaborating the mathematical models representing the whole of the installation (reactor block and cooling circuit) from the point of view of neutrons as well as thermodynamics, the analogue diagrams and digital codes required for simulating incidents, control and stability of the reactor were established. Considerable effort was made to obtain a greater precision than in the usual methods, either by using smaller intervals, or by the use of formulations closer to the real system, or even analytically soluble. The study of incidents was carried out on analog computer for the whole system, and digital computer for the reactor block alone or the installation functioning with a single thermal circuit. A special complementary programme - which so far as we know, was used for the first time here for sodium reactors - which takes into account the behaviour of the reactor beyond the boiling point of sodium was refined on the basis of some simplifying assumptions. The investigation of incidents has served to determine: - The intrinsic safety of the reactor, i.e. its behaviour-under accident conditions without the intervention of the safety systems; - The behaviour of the installation under normal accident conditions, i.e. with the safety systems functioning, and the definition and organisation of the latter ; - the comparison of the two versions investigated (metal or oxide fuel) for the choice of the first loading of the reactor; - the determination of thermal shocks (amplitudes and gradients suffered by the structures during probable incidents) to be used in the test on the full-scale model of the reactor. The stability tests were carried out digitally

  15. Language control in different contexts: the behavioural ecology of bilingual speakers

    Directory of Open Access Journals (Sweden)

    David William Green

    2011-05-01

    Full Text Available This paper proposes that different experimental contexts (single or dual language contexts permit different neural loci at which words in the target language can be selected. However, in order to develop a fuller understanding of the neural circuit mediating language control we need to consider the community context in which bilingual speakers typically use their two languages (the behavioural ecology of bilingual speakers. The contrast between speakers from code-switching and non-code switching communities offers a way to increase our understanding of the cortical, subcortical and, in particular, cerebellar structures involved in language control. It will also help us identify the non-verbal behavioural correlates associated with these control processes.

  16. Silver-indium-cadmium control rod behaviour during a severe reactor accident

    International Nuclear Information System (INIS)

    Bowsher, B.R.; Jenkins, R.A.; Nichols, A.L.; Rowe, N.A.; Simpson, J.A.H.

    1986-04-01

    An alloy of silver, indium and cadmium is commonly used as control rod material in pressurised water reactors (PWRs). The behaviour of this alloy has been studied in a series of experiments using an induction furnace to achieve temperatures up to 1900K. The aerosols released from overheated clad and unclad control rod samples have been characterised in both steam and inert atmospheres. Mass balance experiments have been undertaken to determine the distribution of the control rod alloy constituents following rupture of the cladding, and this work has been supported by thermogravimetric studies of silver-indium mixtures. Metallographic studies were also undertaken to assess the failure mode of the stainless steel cladding and the interaction of the molten alloy with Zircaloy. The results of this work are discussed in terms of aerosol/vapour behaviour during severe reactor accidents. (author)

  17. Diagnosis of dynamic systems based on explicit and implicit behavioural models: an application to gas turbines in Esprit Project Tiger

    Energy Technology Data Exchange (ETDEWEB)

    Trave-Massuyes, L. [Centre National de la Recherche Scientifique (CNRS), 31 - Toulouse (France); Milne, R.

    1995-12-31

    We are interested in the monitoring and diagnosis of dynamic systems. In our work, we are combining explicit temporal models of the behaviour of a dynamic system with implicit behavioural models supporting model based approaches. This work is drive by the needs of and applied to, two gas turbines of very different size and power. In this paper we describe the problems of building systems for these domains and illustrate how we have developed a system where these two approaches complement each other to provide a comprehensive fault detection and diagnosis system. We also explore the strengths and weaknesses of each approach. The work described here is currently working continuously, on line to a gas turbine in a major chemical plant. (author) 24 refs.

  18. Diagnosis of dynamic systems based on explicit and implicit behavioural models: an application to gas turbines in Esprit Project Tiger

    Energy Technology Data Exchange (ETDEWEB)

    Trave-Massuyes, L [Centre National de la Recherche Scientifique (CNRS), 31 - Toulouse (France); Milne, R

    1996-12-31

    We are interested in the monitoring and diagnosis of dynamic systems. In our work, we are combining explicit temporal models of the behaviour of a dynamic system with implicit behavioural models supporting model based approaches. This work is drive by the needs of and applied to, two gas turbines of very different size and power. In this paper we describe the problems of building systems for these domains and illustrate how we have developed a system where these two approaches complement each other to provide a comprehensive fault detection and diagnosis system. We also explore the strengths and weaknesses of each approach. The work described here is currently working continuously, on line to a gas turbine in a major chemical plant. (author) 24 refs.

  19. Coupled dynamic systems and Le Chatelier's principle in noise control

    Science.gov (United States)

    Maidanik, G.; Becker, K. J.

    2004-05-01

    Investigation of coupling an externally driven dynamic system-a master dynamic system-to a passive one-an adjunct dynamic system-reveals that the response of the adjunct dynamic system affects the precoupled response of the master dynamic system. The responses, in the two dynamic systems when coupled, are estimated by the stored energies (Es) and (E0), respectively. Since the adjunct dynamic system, prior to coupling, was with zero (0) stored energy, E0s=0, the precoupled stored energy (E00) in the master dynamic system is expected to be reduced to (E0) when coupling is instituted; i.e., one expects E0control of the master dynamic system would result from the coupling. It is argued that the change in the disposition of the stored energies as just described may not be the only change. The coupling may influence the external input power into the master dynamic system which may interfere with the expected noise control. Indeed, the coupling may influence the external input power such that the expected beneficial noise control may not materialize. Examples of these kinds of noise control reversals are cited.

  20. Advances in analysis and control of timedelayed dynamical systems

    CERN Document Server

    Sun, Jianqiao

    2013-01-01

    Analysis and control of timedelayed systems have been applied in a wide range of applications, ranging from mechanical, control, economic, to biological systems. Over the years, there has been a steady stream of interest in timedelayed dynamic systems, this book takes a snap shot of recent research from the world leading experts in analysis and control of dynamic systems with time delay to provide a bird's eye view of its development. The topics covered in this book include solution methods, stability analysis and control of periodic dynamic systems with time delay, bifurcations, stochastic dy

  1. A behavioural and electrophysiological investigation of the effect of bilingualism on aging and cognitive control.

    Science.gov (United States)

    Kousaie, Shanna; Phillips, Natalie A

    2017-01-08

    Given previous, but inconsistent, findings of language group differences on cognitive control tasks the current investigation examined whether such differences could be demonstrated in a sample of older bilingual adults. Monolingual and bilingual older adults performed three cognitive control tasks that have previously been used in the literature (i.e., Stroop, Simon and flanker tasks) while brain electrophysiological recordings took place. Both behavioural (response time and accuracy) and event-related brain potentials (ERPs; N2 and P3 amplitude and latency) were compared across the two language groups. Processing differences between monolinguals and bilinguals were identified for each task, although the locus differed across the tasks. Language group differences were most clear in the Stroop task, with bilinguals showing superior performance both behaviourally and electrophysiologically. In contrast, for the Simon and flanker tasks there were electrophysiological differences indicating language group processing differences at the level of conflict monitoring (Simon task only) and stimulus categorization (Simon and flanker tasks), but no behavioural differences. These findings support suggestions that these three tasks that are often used to examine executive control processes show little convergent validity; however, there are clear language group differences for each task that are suggestive of superior performance for bilinguals, with behavioural differences emerging only in the linguistic Stroop task. Furthermore, it is clear that behavioural measures alone do not capture the language group effects in their entirety, and perhaps processing differences between language groups are more marked in a sample of older adults who are experiencing age-related cognitive changes than in younger adults who are at the peak of their cognitive capacity. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Optimal control of HIV/AIDS dynamic: Education and treatment

    Science.gov (United States)

    Sule, Amiru; Abdullah, Farah Aini

    2014-07-01

    A mathematical model which describes the transmission dynamics of HIV/AIDS is developed. The optimal control representing education and treatment for this model is explored. The existence of optimal Control is established analytically by the use of optimal control theory. Numerical simulations suggest that education and treatment for the infected has a positive impact on HIV/AIDS control.

  3. Nonlinear dynamic behaviour of a rotor-foundation system coupled through passive magnetic bearings with magnetic anisotropy - Theory and experiment

    DEFF Research Database (Denmark)

    Enemark, Søren; Santos, Ilmar F.

    2016-01-01

    In this work, the nonlinear dynamic behaviour of a vertical rigid rotor interacting with a flexible foundation by means of two passive magnetic bearings is quantified and evaluated. The quantification is based on theoretical and experimental investigation of the non-uniformity (anisotropy......) of the magnetic field and the weak nonlinearity of the magnetic forces. Through mathematical modelling the nonlinear equations of motion are established for describing the shaft and bearing housing lateral dynamics coupled via the nonlinear and non-uniform magnetic forces. The equations of motion are solved...

  4. Dynamic Primitives in the Control of Locomotion

    Directory of Open Access Journals (Sweden)

    Neville eHogan

    2013-06-01

    Full Text Available Humans achieve locomotor dexterity that far exceeds the capability of modern robots, yet this is achieved despite slower actuators, imprecise sensors and vastly slower communication. We propose that this spectacular performance arises from encoding motor commands in terms of dynamic primitives. We propose three primitives as a foundation for a comprehensive theoretical framework that can embrace a wide range of upper- and lower-limb behaviors. Building on previous work that suggested discrete and rhythmic movements as elementary dynamic behaviors, we define submovements and oscillations: As discrete movements cannot be combined with sufficient flexibility, we argue that suitably-defined submovements are primitives. As the term rhythmic may be ambiguous, we define oscillations as the corresponding class of primitives. We further propose mechanical impedances as a third class of dynamic primitives, necessary for interaction with the physical environment. Combination of these three classes of primitive requires care. One approach is through a generalized equivalent network: a virtual trajectory composed of simultaneous and/or sequential submovements and/or oscillations that interacts with mechanical impedances to produce observable forces and motions. Reliable experimental identification of these dynamic primitives presents challenges: Identification of mechanical impedances is exquisitely sensitive to assumptions about their dynamic structure; identification of submovements and oscillations is sensitive to their assumed form and to details of the algorithm used to extract them. Some methods to address these challenges are presented. Some implications of this theoretical framework for locomotor rehabilitation are considered.

  5. Dynamic primitives in the control of locomotion.

    Science.gov (United States)

    Hogan, Neville; Sternad, Dagmar

    2013-01-01

    Humans achieve locomotor dexterity that far exceeds the capability of modern robots, yet this is achieved despite slower actuators, imprecise sensors, and vastly slower communication. We propose that this spectacular performance arises from encoding motor commands in terms of dynamic primitives. We propose three primitives as a foundation for a comprehensive theoretical framework that can embrace a wide range of upper- and lower-limb behaviors. Building on previous work that suggested discrete and rhythmic movements as elementary dynamic behaviors, we define submovements and oscillations: as discrete movements cannot be combined with sufficient flexibility, we argue that suitably-defined submovements are primitives. As the term "rhythmic" may be ambiguous, we define oscillations as the corresponding class of primitives. We further propose mechanical impedances as a third class of dynamic primitives, necessary for interaction with the physical environment. Combination of these three classes of primitive requires care. One approach is through a generalized equivalent network: a virtual trajectory composed of simultaneous and/or sequential submovements and/or oscillations that interacts with mechanical impedances to produce observable forces and motions. Reliable experimental identification of these dynamic primitives presents challenges: identification of mechanical impedances is exquisitely sensitive to assumptions about their dynamic structure; identification of submovements and oscillations is sensitive to their assumed form and to details of the algorithm used to extract them. Some methods to address these challenges are presented. Some implications of this theoretical framework for locomotor rehabilitation are considered.

  6. DYNAMICS BASED CONTROL OF A SKID STEERING MOBILE ROBOT

    Directory of Open Access Journals (Sweden)

    Osama Elshazly

    2016-06-01

    Full Text Available In this paper, development of a reduced order, augmented dynamics-drive model that combines both the dynamics and drive subsystems of the skid steering mobile robot (SSMR is presented. A Linear Quadratic Regulator (LQR control algorithm with feed-forward compensation of the disturbances part included in the reduced order augmented dynamics-drive model is designed. The proposed controller has many advantages such as its simplicity in terms of design and implementation in comparison with complex nonlinear control schemes that are usually designed for this system. Moreover, the good performance is also provided by the controller for the SSMR comparable with a nonlinear controller based on the inverse dynamics which depends on the availability of an accurate model describing the system. Simulation results illustrate the effectiveness and enhancement provided by the proposed controller.

  7. Efficient finite element modelling for the investigation of the dynamic behaviour of a structure with bolted joints

    Science.gov (United States)

    Omar, R.; Rani, M. N. Abdul; Yunus, M. A.; Mirza, W. I. I. Wan Iskandar; Zin, M. S. Mohd

    2018-04-01

    A simple structure with bolted joints consists of the structural components, bolts and nuts. There are several methods to model the structures with bolted joints, however there is no reliable, efficient and economic modelling methods that can accurately predict its dynamics behaviour. Explained in this paper is an investigation that was conducted to obtain an appropriate modelling method for bolted joints. This was carried out by evaluating four different finite element (FE) models of the assembled plates and bolts namely the solid plates-bolts model, plates without bolt model, hybrid plates-bolts model and simplified plates-bolts model. FE modal analysis was conducted for all four initial FE models of the bolted joints. Results of the FE modal analysis were compared with the experimental modal analysis (EMA) results. EMA was performed to extract the natural frequencies and mode shapes of the test physical structure with bolted joints. Evaluation was made by comparing the number of nodes, number of elements, elapsed computer processing unit (CPU) time, and the total percentage of errors of each initial FE model when compared with EMA result. The evaluation showed that the simplified plates-bolts model could most accurately predict the dynamic behaviour of the structure with bolted joints. This study proved that the reliable, efficient and economic modelling of bolted joints, mainly the representation of the bolting, has played a crucial element in ensuring the accuracy of the dynamic behaviour prediction.

  8. Experimental Study on Wing Crack Behaviours in Dynamic-Static Superimposed Stress Field Using Caustics and High-Speed Photography

    Directory of Open Access Journals (Sweden)

    L.Y. Yang

    2014-07-01

    Full Text Available During the drill-and-blast progress in rock tunnel excavation of great deep mine, rock fracture is evaluated by both blasting load and pre-exiting earth stress (pre-compression. Many pre-existing flaws in the rock mass, like micro-crack, also seriously affect the rock fracture pattern. Under blasting load with pre-compression, micro-cracks initiate, propagate and grow to be wing cracks. With an autonomous design of static-dynamic loading system, dynamic and static loads were applied on some PMMA plate specimen with pre-existing crack, and the behaviour of the wing crack was tested by caustics corroding with a high-speed photography. Four programs with different static loading modes that generate different pre-compression fields were executed, and the length, velocity of the blasting wing crack and dynamic stress intensity factor (SIF at the wing crack tip were analyzed and discussed. It is found that the behaviour of blasting-induced wing crack is affected obviously by blasting and pre-compression. And pre-compression, which is vertical to the direction of the wing crack propagation, hinders the crack propagation. Furthermore, the boundary constraint condition plays an important role on the behaviour of blasting induced crack during the experiment.

  9. Dynamic Intelligent Feedback Scheduling in Networked Control Systems

    Directory of Open Access Journals (Sweden)

    Hui-ying Chen

    2013-01-01

    Full Text Available For the networked control system with limited bandwidth and flexible workload, a dynamic intelligent feedback scheduling strategy is proposed. Firstly, a monitor is used to acquire the current available network bandwidth. Then, the new available bandwidth in the next interval is predicted by using LS_SVM approach. At the same time, the dynamic performance indices of all control loops are obtained with a two-dimensional fuzzy logic modulator. Finally, the predicted network bandwidth is dynamically allocated by the bandwidth manager and the priority allocator in terms of the loops' dynamic performance indices. Simulation results show that the sampling periods and priorities of control loops are adjusted timely according to the network workload condition and the dynamic performance of control loops, which make the system running in the optimal state all the time.

  10. Dynamical control of chaos by slave-master feedback

    International Nuclear Information System (INIS)

    Behnia, S.; Akhshani, A.

    2009-01-01

    Techniques for stabilizing unstable state in nonlinear dynamical systems using small perturbations fall into three general categories: feedback, non-feedback schemes, and a combination of feedback and non-feedback. However, the general problem of finding conditions for creation or suppression of chaos still remains open. We describe a method for dynamical control of chaos. This method is based on a definition of the hierarchy of solvable chaotic maps with dynamical parameter as a control parameter. In order to study the new mechanism of control of chaotic process, Kolmogorov-Sinai entropy of the chaotic map with dynamical parameter based on discussion the properties of invariant measure have been calculated and confirmed by calculation of Lyapunov exponents. The introduced chaotic maps can be used as dynamical control.

  11. Cross-cultural patterns in dynamic ratings of positive and negative natural emotional behaviour.

    Science.gov (United States)

    Sneddon, Ian; McKeown, Gary; McRorie, Margaret; Vukicevic, Tijana

    2011-02-18

    Studies of cross-cultural variations in the perception of emotion have typically compared rates of recognition of static posed stimulus photographs. That research has provided evidence for universality in the recognition of a range of emotions but also for some systematic cross-cultural variation in the interpretation of emotional expression. However, questions remain about how widely such findings can be generalised to real life emotional situations. The present study provides the first evidence that the previously reported interplay between universal and cultural influences extends to ratings of natural, dynamic emotional stimuli. Participants from Northern Ireland, Serbia, Guatemala and Peru used a computer based tool to continuously rate the strength of positive and negative emotion being displayed in twelve short video sequences by people from the United Kingdom engaged in emotional conversations. Generalized additive mixed models were developed to assess the differences in perception of emotion between countries and sexes. Our results indicate that the temporal pattern of ratings is similar across cultures for a range of emotions and social contexts. However, there are systematic differences in intensity ratings between the countries, with participants from Northern Ireland making the most extreme ratings in the majority of the clips. The results indicate that there is strong agreement across cultures in the valence and patterns of ratings of natural emotional situations but that participants from different cultures show systematic variation in the intensity with which they rate emotion. Results are discussed in terms of both 'in-group advantage' and 'display rules' approaches. This study indicates that examples of natural spontaneous emotional behaviour can be used to study cross-cultural variations in the perception of emotion.

  12. Dynamic behaviour of raft and pile foundations tests and computational models. Pt. 1

    International Nuclear Information System (INIS)

    Betbeder, J.; Garnier, J.C.; Gauvain, J.; Jeandidier, C.

    1981-01-01

    Pile foundations are commonly used for many types of buildings where the bearing capacity of soil is poor. For nuclear power plants buildings, however, there seems to be a fairly general reluctancy to accept design on piles, as it is considered difficult to demonstrate the safety of these foundations with respect to earthquakes, due to the relative lack of validation of the currently available aseismic design methods. Being conscious that pile foundations might be worth considering for future nuclear sites in France and that the reliability of design methods should be backed by experimental data, ELECTRICITE DE FRANCE decided in 1978 to undertake a series of tests, aimed at assessing the validity of computational models for seismic behaviour of pile foundations and trying to define better models if necessary. These tests on reduced scale structure, including various types of raft and pile foundations and different kinds of dynamic excitation (harmonic, earthquake simulation, impulsive release of a static force) have been made at the NICE airport site. The present paper deals with the general description of the tests and the first part of interpretation work, limited to in-structure harmonic excitation and earthquake simulation tests analyzed by simple spring -dashpot analytical models. The two following papers (K5-6 and K5-7) are devoted to specialized topics in relation with the interpretation of tests, i-e ground motions analysis for earthquake simulation and research work on a new computational model. Although preliminary conclusions can be drawn from the results obtained so far, further work will be necessary to reach a conclusive assessment on this difficult subject. (orig.)

  13. Effect of intermolecular force on the static/dynamic behaviour of M/NEM devices

    Science.gov (United States)

    Kim, Namjung; Aluru, N. R.

    2014-12-01

    Advances made in the fabrication of micro/nano-electromechanical (M/NEM) devices over the last ten years necessitate the understanding of the attractive force that arises from quantum fluctuations (generally referred to as Casimir effects) [Casimir H B G 1948 Proc. K. Ned. Akad. Wet. 51 793]. The fundamental mechanisms underlying quantum fluctuations have been actively investigated through various theoretical and experimental approaches. However, the effect of the force on M/NEM devices has not been fully understood yet, especially in the transition region involving gaps ranging from 10 nm to 1 μm, due to the complexity of the force. Here, we numerically calculate the Casimir effects in M/NEM devices by using the Lifshitz formula, the general expression for the Casimir effects [Lifshitz E 1956 Sov. Phys. JETP 2 73]. Since the Casimir effects are highly dependent on the permittivity of the materials, the Kramer-Kronig relation [Landau L D, Lifshitz E M and Pitaevskii L P 1984 Electrodynamics of Continuous Media (New York: Pergamon Press)] and the optical data for metals and dielectrics are used in order to obtain the permittivity. Several simplified models for the permittivity of the materials, such as the Drude and Lorentz models [Jackson J D 1975 Classical Electrodynamics (New York: Wiley)], are also used to extrapolate the optical data. Important characteristic values of M/NEM devices, such as the pull-in voltage, pull-in gap, detachment length, etc, are calculated for devices operating in the transition region. Our results show that accurate predictions for the pull-in behaviour are possible when the Lifshitz formula is used instead of the idealized expressions for Casimir effects. We expand this study into the dynamics of M/NEM devices, so that the time and frequency response of M/NEM devices with Casimir effects can be explored.

  14. Effect of intermolecular force on the static/dynamic behaviour of M/NEM devices

    International Nuclear Information System (INIS)

    Kim, Namjung; Aluru, N R

    2014-01-01

    Advances made in the fabrication of micro/nano-electromechanical (M/NEM) devices over the last ten years necessitate the understanding of the attractive force that arises from quantum fluctuations (generally referred to as Casimir effects) [Casimir H B G 1948 Proc. K. Ned. Akad. Wet. 51 793]. The fundamental mechanisms underlying quantum fluctuations have been actively investigated through various theoretical and experimental approaches. However, the effect of the force on M/NEM devices has not been fully understood yet, especially in the transition region involving gaps ranging from 10 nm to 1 μm, due to the complexity of the force. Here, we numerically calculate the Casimir effects in M/NEM devices by using the Lifshitz formula, the general expression for the Casimir effects [Lifshitz E 1956 Sov. Phys. JETP 2 73]. Since the Casimir effects are highly dependent on the permittivity of the materials, the Kramer–Kronig relation [Landau L D, Lifshitz E M and Pitaevskii L P 1984 Electrodynamics of Continuous Media (New York: Pergamon Press)] and the optical data for metals and dielectrics are used in order to obtain the permittivity. Several simplified models for the permittivity of the materials, such as the Drude and Lorentz models [Jackson J D 1975 Classical Electrodynamics (New York: Wiley)], are also used to extrapolate the optical data. Important characteristic values of M/NEM devices, such as the pull-in voltage, pull-in gap, detachment length, etc, are calculated for devices operating in the transition region. Our results show that accurate predictions for the pull-in behaviour are possible when the Lifshitz formula is used instead of the idealized expressions for Casimir effects. We expand this study into the dynamics of M/NEM devices, so that the time and frequency response of M/NEM devices with Casimir effects can be explored. (paper)

  15. Cross-cultural patterns in dynamic ratings of positive and negative natural emotional behaviour.

    Directory of Open Access Journals (Sweden)

    Ian Sneddon

    2011-02-01

    Full Text Available Studies of cross-cultural variations in the perception of emotion have typically compared rates of recognition of static posed stimulus photographs. That research has provided evidence for universality in the recognition of a range of emotions but also for some systematic cross-cultural variation in the interpretation of emotional expression. However, questions remain about how widely such findings can be generalised to real life emotional situations. The present study provides the first evidence that the previously reported interplay between universal and cultural influences extends to ratings of natural, dynamic emotional stimuli.Participants from Northern Ireland, Serbia, Guatemala and Peru used a computer based tool to continuously rate the strength of positive and negative emotion being displayed in twelve short video sequences by people from the United Kingdom engaged in emotional conversations. Generalized additive mixed models were developed to assess the differences in perception of emotion between countries and sexes. Our results indicate that the temporal pattern of ratings is similar across cultures for a range of emotions and social contexts. However, there are systematic differences in intensity ratings between the countries, with participants from Northern Ireland making the most extreme ratings in the majority of the clips.The results indicate that there is strong agreement across cultures in the valence and patterns of ratings of natural emotional situations but that participants from different cultures show systematic variation in the intensity with which they rate emotion. Results are discussed in terms of both 'in-group advantage' and 'display rules' approaches. This study indicates that examples of natural spontaneous emotional behaviour can be used to study cross-cultural variations in the perception of emotion.

  16. Rhythmic behaviour of marine benthopelagic species and the synchronous dynamics of benthic communities

    Science.gov (United States)

    Aguzzi, Jacopo; Sbragaglia, Valerio; Tecchio, Samuele; Navarro, Joan; Company, Joan B.

    2015-01-01

    Light-intensity cycles drive the relentless motion of species in the oceans, and water column migrants may cyclically make contact with the seabed, hence influencing the temporal dynamism of benthic ecosystems. The influence of light on this process remains largely unknown to date. In this study, we focus on the occurrence of day-night changes in benthic communities on the western Mediterranean continental shelf (100 m depth) and slope (400 m depth) as a potential result of a behaviourally sustained benthopelagic coupling. We analysed fluctuations in species abundance based on trawling at hourly intervals over a 4-day period as a proxy of activity rhythms at the seabed. We also measured light in situ to assess how the depth-related decrease of its intensity influences species rhythms and the occurrence of the putative benthopelagic synchronisation. Temporal similarities in the catch patterns for different species were screened by dendrogram analysis. On the continental shelf, species performing diel migrations (i.e., over a 24 h period) that were either vertical (i.e., benthopelagic) or horizontal across depths (i.e., nektobenthic) clustered together separately from the more sedentary endobenthic and epibenthic species. At the same depth, waveform analysis showed a significant diurnal increase in the catch of water column species and benthic species at night. Such coupling was absent on the continental slope, where light intensity was several orders of magnitude lower than that on the shelf. Our data indicate that diel activity rhythms, which are well known for vertical pelagic migrators, are also evident in the benthos. We discuss the role of light as a major evolutionary driver shaping the composition and biodiversity of benthic communities via visual predation.

  17. Belt conveyor dynamics in transient operation for speed control

    OpenAIRE

    He, D.; Pang, Y.; Lodewijks, G.

    2016-01-01

    Belt conveyors play an important role in continuous dry bulk material transport, especially at the mining industry. Speed control is expected to reduce the energy consumption of belt conveyors. Transient operation is the operation of increasing or decreasing conveyor speed for speed control. According to literature review, current research rarely takes the conveyor dynamics in transient operation into account. However, in belt conveyor speed control, the conveyor dynamic behaviors are signifi...

  18. Dynamics and Control of a Flexible Solar Sail

    OpenAIRE

    Jiafu Liu; Siyuan Rong; Fan Shen; Naigang Cui

    2014-01-01

    Solar sail can merely make use of solar radiation pressure (SRP) force as the thrust for space missions. The attitude dynamics is obtained for the highly flexible solar sail with control vanes, sliding masses, and a gimbaled control boom. The vibration equations are derived considering the geometric nonlinearity of the sail structure subjected to the forces generated by the control vanes, solar radiation pressure (SRP), and sliding masses. Then the dynamic models for attitude/vibration contr...

  19. Chaos control of chaotic dynamical systems using backstepping design

    International Nuclear Information System (INIS)

    Yassen, M.T.

    2006-01-01

    This work presents chaos control of chaotic dynamical systems by using backstepping design method. This technique is applied to achieve chaos control for each of the dynamical systems Lorenz, Chen and Lue systems. Based on Lyapunov stability theory, control laws are derived. We used the same technique to enable stabilization of chaotic motion to a steady state as well as tracking of any desired trajectory to be achieved in a systematic way. Numerical simulations are shown to verify the results

  20. Smoking behaviours and attitudes toward tobacco control among assistant environmental health officer trainees.

    Science.gov (United States)

    Tee, G H; Gurpreet, K; Hairi, N N; Zarihah, Z; Fadzilah, K

    2013-12-01

    Assistant environmental health officers (AEHO) are health care providers (HCPs) who act as enforcers, educators and trusted role models for the public. This is the first study to explore smoking behaviour and attitudes toward tobacco control among future HCPs. Almost 30% of AEHO trainees did not know the role of AEHOs in counselling smokers to stop smoking, but 91% agreed they should not smoke before advising others not to do so. The majority agreed that tobacco control regulations may be used as a means of reducing the prevalence of smoking. Future AEHOs had positive attitudes toward tobacco regulations but lacked understanding of their responsibility in tobacco control measures.

  1. The dynamics of consumer behaviour: On habit, discontent, and other fish to fry

    DEFF Research Database (Denmark)

    Scholderer, Joachim; Trondsen, Torbjørn

    2008-01-01

    Recent research has drawn attention to the role of past behaviour and habit in the overall structure of consumer behaviour. We argue that in cross-sectional data past behaviour and habit must be confounded with present beliefs and attitudes when the behaviour in question has been enacted numerous...... supply. These negative evaluations, in turn, prompted substitution of traditional seafood with newly available, processed seafood products and an increasing dominance of aqua-cultured species. The theoretical discussion focuses on the inability of static models of consumer behaviour (in particular...... times before. To disentangle the effects, longitudinal data were collected from a large panel of Norwegian consumers (effective N=4184) in 1996, 2000, and 2004. Cross-lagged panel analysis indicated that higher consumption of traditional seafood led to increasingly negative evaluations of the product...

  2. The Quadrotor Dynamic Modeling and Indoor Target Tracking Control Method

    Directory of Open Access Journals (Sweden)

    Dewei Zhang

    2014-01-01

    Full Text Available A reliable nonlinear dynamic model of the quadrotor is presented. The nonlinear dynamic model includes actuator dynamic and aerodynamic effect. Since the rotors run near a constant hovering speed, the dynamic model is simplified at hovering operating point. Based on the simplified nonlinear dynamic model, the PID controllers with feedback linearization and feedforward control are proposed using the backstepping method. These controllers are used to control both the attitude and position of the quadrotor. A fully custom quadrotor is developed to verify the correctness of the dynamic model and control algorithms. The attitude of the quadrotor is measured by inertia measurement unit (IMU. The position of the quadrotor in a GPS-denied environment, especially indoor environment, is estimated from the downward camera and ultrasonic sensor measurements. The validity and effectiveness of the proposed dynamic model and control algorithms are demonstrated by experimental results. It is shown that the vehicle achieves robust vision-based hovering and moving target tracking control.

  3. Cognitive-behavioural suicide prevention for male prisoners: a pilot randomized controlled trial.

    Science.gov (United States)

    Pratt, D; Tarrier, N; Dunn, G; Awenat, Y; Shaw, J; Ulph, F; Gooding, P

    2015-12-01

    Prisoners have an exceptional risk of suicide. Cognitive-behavioural therapy for suicidal behaviour has been shown to offer considerable potential, but has yet to be formally evaluated within prisons. This study investigated the feasibility of delivering and evaluating a novel, manualized cognitive-behavioural suicide prevention (CBSP) therapy for suicidal male prisoners. A pilot randomized controlled trial of CBSP in addition to treatment as usual (CBSP; n = 31) compared with treatment as usual (TAU; n = 31) alone was conducted in a male prison in England. The primary outcome was self-injurious behaviour occurring within the past 6 months. Secondary outcomes were dimensions of suicidal ideation, psychiatric symptomatology, personality dysfunction and psychological determinants of suicide, including depression and hopelessness. The trial was prospectively registered (number ISRCTN59909209). Relative to TAU, participants receiving CBSP therapy achieved a significantly greater reduction in suicidal behaviours with a moderate treatment effect [Cohen's d = -0.72, 95% confidence interval -1.71 to 0.09; baseline mean TAU: 1.39 (S.D. = 3.28) v. CBSP: 1.06 (S.D. = 2.10), 6 months mean TAU: 1.48 (S.D. = 3.23) v. CBSP: 0.58 (S.D. = 1.52)]. Significant improvements were achieved on measures of psychiatric symptomatology and personality dysfunction. Improvements on psychological determinants of suicide were non-significant. More than half of the participants in the CBSP group achieved a clinically significant recovery by the end of therapy, compared with a quarter of the TAU group. The delivery and evaluation of CBSP therapy within a prison is feasible. CBSP therapy offers significant promise in the prevention of prison suicide and an adequately powered randomized controlled trial is warranted.

  4. Dynamic behaviour of Li batteries in hydrogen fuel cell power trains

    Science.gov (United States)

    Veneri, O.; Migliardini, F.; Capasso, C.; Corbo, P.

    A Li ion polymer battery pack for road vehicles (48 V, 20 Ah) was tested by charging/discharging tests at different current values, in order to evaluate its performance in comparison with a conventional Pb acid battery pack. The comparative analysis was also performed integrating the two storage systems in a hydrogen fuel cell power train for moped applications. The propulsion system comprised a fuel cell generator based on a 2.5 kW polymeric electrolyte membrane (PEM) stack, fuelled with compressed hydrogen, an electric drive of 1.8 kW as nominal power, of the same typology of that installed on commercial electric scooters (brushless electric machine and controlled bidirectional inverter). The power train was characterized making use of a test bench able to simulate the vehicle behaviour and road characteristics on driving cycles with different acceleration/deceleration rates and lengths. The power flows between fuel cell system, electric energy storage system and electric drive during the different cycles were analyzed, evidencing the effect of high battery currents on the vehicle driving range. The use of Li batteries in the fuel cell power train, adopting a range extender configuration, determined a hydrogen consumption lower than the correspondent Pb battery/fuel cell hybrid vehicle, with a major flexibility in the power management.

  5. Dynamic behaviour of solvent contactors in fuel reprocessing plants- an analysis

    Energy Technology Data Exchange (ETDEWEB)

    Raju, R P; Siddiqui, H R [Nuclear Waste Management Group, Bhabha Atomic Research Centre, Mumbai (India); Murthy, K K; Kansra, V P [Fuel Reprocessing Group, Bhabha Atomic Research Centre, Mumbai (India)

    1994-06-01

    Fuel reprocessing plants carry out separation of useful fissile and fertile materials from spent nuclear fuels by isolating highly radioactive fission products using solvent extraction method. In the fuel reprocessing step of nuclear fuel cycle, optimisation of process parameters in the PUREX flowsheet design is of great importance particularly on account of the need to realize high degree of recovery of fissile and fertile materials and to ensure proper control on concentrations of fissile element in process streams for avoidance of criticality. In counter-current solvent contactors of PUREX flowsheet there are a variety of processes conditions which may cause plutonium accumulations that requires attention to ascertain safe Pu concentrations within the contactors. A study was carried out using the PUREX process mathematical model Solvent Extraction Program Having Interacting Solutes (SEPHIS) for pulsed solvent contactors in PREFRE-1, Tarapur and PREFRE-2, Kalpakkam flowsheets for optimising the process parameters in plutonium purification cycles. The study was extended to predict the behaviour of contactors handling plutonium bearing solutions under certain anticipated deviations in the process parameters. Modifications wherever necessary were carried out to the original SEPHIS code. This paper discusses the results obtained during this analysis. (author). 2 figs., 2 tabs.

  6. Structure-based control of complex networks with nonlinear dynamics.

    Science.gov (United States)

    Zañudo, Jorge Gomez Tejeda; Yang, Gang; Albert, Réka

    2017-07-11

    What can we learn about controlling a system solely from its underlying network structure? Here we adapt a recently developed framework for control of networks governed by a broad class of nonlinear dynamics that includes the major dynamic models of biological, technological, and social processes. This feedback-based framework provides realizable node overrides that steer a system toward any of its natural long-term dynamic behaviors, regardless of the specific functional forms and system parameters. We use this framework on several real networks, identify the topological characteristics that underlie the predicted node overrides, and compare its predictions to those of structural controllability in control theory. Finally, we demonstrate this framework's applicability in dynamic models of gene regulatory networks and identify nodes whose override is necessary for control in the general case but not in specific model instances.

  7. Informal methods of social control: managing speed behaviour on SA roads

    CSIR Research Space (South Africa)

    Venter, Karien

    2009-09-01

    Full Text Available . These normally stems from a soar in prices related to transport services. The fluctuating fuel price influenced South Africans one way or another. The theory put forward in the first part of the paper considered the possibility of whether or not the escalation... crisis) and in 1979 (Iranian fuel crisis), driver behaviour were adapted accordingly. Along with the lowering of speed limits (Fieldwick and Fernie: 1980) the South African government at the time also introduced another type of social control...

  8. Behavioural system identification of visual flight speed control in Drosophila melanogaster.

    Science.gov (United States)

    Rohrseitz, Nicola; Fry, Steven N

    2011-02-06

    Behavioural control in many animals involves complex mechanisms with intricate sensory-motor feedback loops. Modelling allows functional aspects to be captured without relying on a description of the underlying complex, and often unknown, mechanisms. A wide range of engineering techniques are available for modelling, but their ability to describe time-continuous processes is rarely exploited to describe sensory-motor control mechanisms in biological systems. We performed a system identification of visual flight speed control in the fruitfly Drosophila, based on an extensive dataset of open-loop responses previously measured under free flight conditions. We identified a second-order under-damped control model with just six free parameters that well describes both the transient and steady-state characteristics of the open-loop data. We then used the identified control model to predict flight speed responses after a visual perturbation under closed-loop conditions and validated the model with behavioural measurements performed in free-flying flies under the same closed-loop conditions. Our system identification of the fruitfly's flight speed response uncovers the high-level control strategy of a fundamental flight control reflex without depending on assumptions about the underlying physiological mechanisms. The results are relevant for future investigations of the underlying neuromotor processing mechanisms, as well as for the design of biomimetic robots, such as micro-air vehicles.

  9. Can the traffic locus of control (T-LOC) scale be successfully used to predict Swedish drivers' speeding behaviour?

    Science.gov (United States)

    Warner, Henriette Wallén; Ozkan, Türker; Lajunen, Timo

    2010-07-01

    The first aim of the present study was to examine the factor structure of the traffic locus of control (T-LOC) scale in a Swedish sample of drivers. The second aim was to examine if this scale can be used to predict drivers' speeding behaviour. A sample of Swedish car owners (N=223) completed a questionnaire including questions based on the traffic locus of control (T-LOC) scale as well as questions about their speeding behaviour. The results showed a five factor solution including own skills, own behaviour, other drivers, vehicle/environment and fate. Own behaviour and vehicle/environment could be used to predict drivers' speeding behaviour on roads with a 90 km/h speed limit while none of the variables included in the traffic locus of control (T-LOC) scale could be used to predict drivers' speeding behaviour on roads with a 50 km/h speed limit. On 90 km/h roads own behaviour was positively related to drivers' speeding behaviour while vehicle/environment was negatively related to their speeding behaviour. Copyright 2010 Elsevier Ltd. All rights reserved.

  10. Combined cycle power plants: A comparison between two different dynamic models to evaluate transient behaviour and residual life

    International Nuclear Information System (INIS)

    Benato, Alberto; Stoppato, Anna; Bracco, Stefano

    2014-01-01

    Highlights: • Two procedures aimed at simulating the dynamic behaviour of power plants are compared. • They both are aimed at predicting the residual life of plant devices. • A single pressure gas-steam combined plant has been modelled. • A good correspondence has been found despite the different approaches used. - Abstract: The deregulated energy market and the increasing quota of electrical capacity covered by non-predictable renewable sources require strongly irregular and discontinuous operation of thermoelectric plants to satisfy users demand and compensate the variability of renewable sources. As a consequence, due to thermo-mechanical fatigue, creep and corrosion, a lifetime reduction of the most critical components occurs. The availability of a procedure able to predict the residual life of plant devices is necessary to assist the management decisions about power plants’ operation and maintenance scheduling. The first step of this procedure is the capability of simulating the plant behaviour versus time by evaluating the trends of the main thermodynamic parameters that describe the plant operation during different transient periods. In this context, the main contribution of the present paper is to propose a complete procedure able to simulate the plant dynamic behaviour and estimate the residual life reduction of some components. Indeed, two different models, developed by two different research groups, of the same single pressure heat recovery steam generator unit are presented and utilized to characterize the dynamic behaviour of the above mentioned power plant. The main thermodynamic variables during different transient operation conditions are predicted and good correspondence between the two methods is obtained. It can be also noted that, when the geometry and size of the devices are considered, the thermal inertia related to heat exchangers tubes, pipes and other physical masses causes a delay in the system response. Moreover, a residual life

  11. Controlled ventilation in gas-heated low-energy houses. Primary energy savings in regard to the users behaviour

    International Nuclear Information System (INIS)

    Luedemann, B.; Schmitz, G.

    1999-01-01

    With the introduction of the energy savings regulation in Germany (ESVO) low-energy buildings will be the standard for new buildings at the turn of the millennium. The heating energy demand will sink around 30 % facing the actual standard. Systems for controlled Ventilation with heat-recovery are often regarded as an essential component to achieve the low-energy standard for buildings. The quota of the ventilation losses in high insulated buildings is up to far over 50 % of the heating energy demand. However, in practice ventilation systems often do not achieve the calculated energy-savings on the heat requirement. Until now, both technical defects of ventilation systems and the tightness of buildings are at the centre of discussion dealing with this problem. Therefore, in a common research project of three gas supply companies, an electricity distribution company and the Department of Technical Thermodynamics at the TUHH, the bandwidth of the possible energy-savings by ventilation systems with heat recovery was investigated by dynamic simulation of the thermal behaviour of buildings and ventilation systems. Above all, the question of the influence of the user behaviour was at the centre of attention. (author)

  12. Practical synchronization on complex dynamical networks via optimal pinning control

    Science.gov (United States)

    Li, Kezan; Sun, Weigang; Small, Michael; Fu, Xinchu

    2015-07-01

    We consider practical synchronization on complex dynamical networks under linear feedback control designed by optimal control theory. The control goal is to minimize global synchronization error and control strength over a given finite time interval, and synchronization error at terminal time. By utilizing the Pontryagin's minimum principle, and based on a general complex dynamical network, we obtain an optimal system to achieve the control goal. The result is verified by performing some numerical simulations on Star networks, Watts-Strogatz networks, and Barabási-Albert networks. Moreover, by combining optimal control and traditional pinning control, we propose an optimal pinning control strategy which depends on the network's topological structure. Obtained results show that optimal pinning control is very effective for synchronization control in real applications.

  13. Robot-Arm Dynamic Control by Computer

    Science.gov (United States)

    Bejczy, Antal K.; Tarn, Tzyh J.; Chen, Yilong J.

    1987-01-01

    Feedforward and feedback schemes linearize responses to control inputs. Method for control of robot arm based on computed nonlinear feedback and state tranformations to linearize system and decouple robot end-effector motions along each of cartesian axes augmented with optimal scheme for correction of errors in workspace. Major new feature of control method is: optimal error-correction loop directly operates on task level and not on joint-servocontrol level.

  14. Dynamics and Controls of Swarms of Femtosatellites

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed research activity is focused on the development of fuel and computationally efficient guidance and control algorithms for spacecraft swarms. The...

  15. Satellite Dynamic Damping via Active Force Control Augmentation

    Science.gov (United States)

    Varatharajoo, Renuganth

    2012-07-01

    An approach that incorporates the Active Force Control (AFC) technique into a conventional Proportional-Derivative (PD) controller is proposed for a satellite active dynamic damping towards a full attitude control. The AFC method has been established to facilitate a robust motion control of dynamical systems in the presence of disturbances, parametric uncertainties and changes that are commonly prevalent in the real-world environment. The usefulness of the method can be extended by introducing intelligent mechanisms to approximate the mass or inertia matrix of the dynamic system to trigger the compensation effect of the controller. AFC is a technique that relies on the appropriate estimation of the inertial or mass parameters of the dynamic system and the measurements of the acceleration and force signals induced by the system if practical implementation is ever considered. In AFC, it is shown that the system subjected to a number of disturbances remains stable and robust via the compensating action of the control strategy. We demonstrate that it is possible to design a spacecraft attitude feedback controller that will ensure the system dynamics set point remains unchanged even in the presence of the disturbances provided that the actual disturbances can be modeled effectively. In order to further facilitate this analysis, a combined energy and attitude control system (CEACS) is proposed as a model satellite attitude control actuator. All the governing equations are established and the proposed satellite attitude control architecture is made amenable to numerical treatments. The results show that the PD-AFC attitude damping performances are superiorly better than that of the solely PD type. It is also shown that the tunings of the AFC system gains are crucial to ensure a better attitude damping performance and this process is mandatory for AFC systems. Finally, the results demonstrate an important satellite dynamic damping enhancement capability using the AFC

  16. Adaptive pseudolinear compensators of dynamic characteristics of automatic control systems

    Science.gov (United States)

    Skorospeshkin, M. V.; Sukhodoev, M. S.; Timoshenko, E. A.; Lenskiy, F. V.

    2016-04-01

    Adaptive pseudolinear gain and phase compensators of dynamic characteristics of automatic control systems are suggested. The automatic control system performance with adaptive compensators has been explored. The efficiency of pseudolinear adaptive compensators in the automatic control systems with time-varying parameters has been demonstrated.

  17. Simulation of the dynamic behaviour of the secondary circuit of a WWER-440 type nuclear power plant Pt. 2

    International Nuclear Information System (INIS)

    Doorenbos, J.; Gacs, A.; Kiss, Zs.

    1987-12-01

    This report describes the dynamic simulation models of the most important controllers of the secondary circuit of a WWER-440 type nuclear power plant, i.e., the hydraulic turbine controller and the level controls of the condenser hotwell and that of the feedwater tank. Simulation results are also presented. (For dynamic simulation models of the primary circuit of WWER-440 type reactors see Reports KFKI--1983-127 and KFKI--1985-08.) (author) 15 figs

  18. Improved confidence in performing nutrition and physical activity behaviours mediates behavioural change in young adults: Mediation results of a randomised controlled mHealth intervention.

    Science.gov (United States)

    Partridge, Stephanie R; McGeechan, Kevin; Bauman, Adrian; Phongsavan, Philayrath; Allman-Farinelli, Margaret

    2017-01-01

    The burden of weight gain disproportionally affects young adults. Understanding the underlying behavioural mechanisms of change in mHealth nutrition and physical activity interventions designed for young adults is important for enhancing and translating effective interventions. First, we hypothesised that knowledge, self-efficacy and stage-of-change for nutrition and physical activity behaviours would improve, and second, that self-efficacy changes in nutrition and physical activity behaviours mediate the behaviour changes observed in an mHealth RCT for prevention of weight gain. Young adults, aged 18-35 years at risk of weight gain (n = 250) were randomly assigned to an mHealth-program, TXT2BFiT, consisting of a three-month intensive phase and six-month maintenance phase or to a control group. Self-reported online surveys at baseline, three- and nine-months assessed nutrition and physical activity behaviours, knowledge, self-efficacy and stage-of-change. The mediating effect of self-efficacy was assessed in multiple PROCESS macro-models for three- and nine-month nutrition and physical activity behaviour change. Young adults randomised to the intervention increased and maintained knowledge of fruit requirements (P = 0.029) compared to controls. Intervention participants' fruit and takeaway behaviours improved to meet recommendations at nine months, with a greater proportion progressing to action or maintenance stage-of-change (P behaviours did not meet recommendations, thereby halting progress to action or maintenance stage-of-change. Indirect effects of improved nutrition and physical activity behaviours at three- and nine-months in the intervention group were explained by changes in self-efficacy, accounting for 8%-37% of the total effect. This provides insights into how the mHealth intervention achieved part of its effects and the importance of improving self-efficacy to facilitate improved eating and physical activity behaviours in young adults

  19. Context, emotion, and the strategic pursuit of goals: Interactions among multiple brain systems controlling motivated behaviour

    Directory of Open Access Journals (Sweden)

    Aaron J Gruber

    2012-08-01

    Full Text Available Motivated behaviour exhibits properties that change with experience and partially dissociate among a number of brain structures. Here, we review evidence from rodent experiments demonstrating that multiple brain systems acquire information in parallel and either cooperate or compete for behavioural control. We propose a conceptual model of systems interaction wherein a ventral emotional memory network involving ventral striatum, amygdala, ventral hippocampus, and ventromedial prefrontal cortex triages behavioural responding to stimuli according to their associated affective outcomes. This system engages autonomic and postural responding (avoiding, ignoring, approaching in accordance with associated stimulus valence (negative, neutral, positive, but does not engage particular operant responses. Rather, this emotional system suppresses or invigorates actions that are selected through competition between goal-directed control involving dorsomedial striatum and habitual control involving dorsolateral striatum. The hippocampus provides contextual specificity to the emotional system, and provides an information rich input to the goal-directed system for navigation and discriminations involving ambiguous contexts, complex sensory configurations, or temporal ordering. The rapid acquisition and high capacity for episodic associations in the emotional system may unburden the more complex goal-directed system and reduce interference in the habit system from processing contingencies of neutral stimuli. Interactions among these systems likely involve inhibitory mechanisms and neuromodulation in the basal ganglia to form a dominant response strategy. Innate traits, training methods, and task demands contribute to the nature of these interactions, which can include incidental learning in non-dominant systems. Addition of these features to reinforcement learning models of decision making may better align theoretical predictions with behavioural and neural

  20. Design features affecting dynamic behaviour of fast reactor cores. Overview paper

    International Nuclear Information System (INIS)

    Kayser, G.; Gouriou, A.

    1982-01-01

    The study of dynamic response of a LMFBR to normal and accidental transients needs first of all a simulation code taking into account all the important effects. The DYN-1 code aims at this target. It represents with a sufficiently accurate meshing the core in a 2D geometry for the thermal and reactivity effects, while the kinetics of this core are calculated with a point model. The primary pool, secondary loops, steam generator are also represented, as well as the control and protective systems. A schematic representation of this code applied to Super Phenix 1 is shown. Simpler codes are sometimes good enough for parametric studies. The dynamic studies of this plant are related to different situations which can be classified in the following groups: normal operation, the stability of the reactor in a steady state situation, or with power or frequency regulation; the normal transients from one power level to another (startup procedures); the incidental situations, with the protective shut-down systems operative (for instance loss of electric supply power); the hypothetical accidental situations without scram. The first three groups of problems arise necessarily in the study of each plant ; the last group is related to very hypothetical situations, the probability of which can be made very low by a high reliability of the shut-down system. Also the need to study them depends on this reliability and subsequently on the philosophy which the licensing authorities adopt

  1. CHAMP: Cognitive behaviour therapy for health anxiety in medical patients, a randomised controlled trial

    Directory of Open Access Journals (Sweden)

    Murphy David

    2011-06-01

    Full Text Available Abstract Background Abnormal health anxiety, also called hypochondriasis, has been successfully treated by cognitive behaviour therapy (CBT in patients recruited from primary care, but only one pilot trial has been carried out among those attending secondary medical clinics where health anxiety is likely to be more common and have a greater impact on services. The CHAMP study extends this work to examine both the clinical and cost effectiveness of CBT in this population. Method/Design The study is a randomized controlled trial with two parallel arms and equal randomization of 466 eligible patients (assuming a 20% drop-out to an active treatment group of 5-10 sessions of cognitive behaviour therapy and to a control group. The aim at baseline, after completion of all assessments but before randomization, was to give a standard simple explanation of the nature of health anxiety for all participants. Subsequently the control group was to receive whatever care might usually be available in the clinics, which is normally a combination of clinical assessment, appropriate tests and reassurance. Those allocated to the active treatment group were planned to receive between 5 and 10 sessions of an adapted form of cognitive behaviour therapy based on the Salkovskis/Warwick model, in which a set of treatment strategies are chosen aimed at helping patients understand the factors that drive and maintain health anxiety. The therapy was planned to be given by graduate research workers, nurses or other health professionals trained for this intervention whom would also have their competence assessed independently during the course of treatment. The primary outcome is reduction in health anxiety symptoms after one year and the main secondary outcome is the cost of care after two years. Discussion This represents the first trial of adapted cognitive behaviour therapy in health anxiety that is large enough to test not only the clinical benefits of treatment but also

  2. Cognitive Models for Learning to Control Dynamic Systems

    National Research Council Canada - National Science Library

    Eberhart, Russ; Hu, Xiaohui; Chen, Yaobin

    2008-01-01

    Report developed under STTR contract for topic "Cognitive models for learning to control dynamic systems" demonstrated a swarm intelligence learning algorithm and its application in unmanned aerial vehicle (UAV) mission planning...

  3. Motor Control Research Requires Nonlinear Dynamics

    Science.gov (United States)

    Guastello, Stephen J.

    2006-01-01

    The author comments on the original article "The Cinderella of psychology: The neglect of motor control in the science of mental life and behavior," by D. A. Rosenbaum. Rosenbaum draws attention to the study of motor control and evaluates seven possible explanations for why the topic has been relatively neglected. The point of this comment is that…

  4. A software tool to estimate the dynamic behaviour of the IP2C samples as sensors for didactic purposes

    International Nuclear Information System (INIS)

    Graziani, S.; Pagano, F.; Pitrone, N.; Umana, E.

    2010-01-01

    Ionic Polymer Polymer Composites (IP 2 Cs) are emerging materials used to realize motion actuators and sensors. In the former case a voltage input is able to cause the membrane to bend while in the latter case by bending an IP 2 C membrane, a voltage output is obtained. In this paper authors introduce a software tool able to estimate the dynamic behaviour for sensors based on IP 2 Cs working in air. In the proposed tool, geometrical quantities that rule the sensing properties of IP 2 C-based transducers are taken into account together with their dynamic characteristics. A graphical interface (GUI) has been developed in order to give a useful tool that allows the user to understand the behaviour and the role of the parameters involved in the transduction phenomena. The tool is based on the idea that a graphical user interface will allow persons not skilled in IP 2 C materials to observe their behaviour and to analyze their characteristics. This could greatly increase the interest of researchers towards this new class of transducers; moreover, it can support the educational activity of students involved in advanced academical courses.

  5. The study of two, three and four dimensional nonlinear dynamics of nuclear fission reactors and effective parameters on its behaviour

    International Nuclear Information System (INIS)

    Tajik, M.; Ghasemizad, A.

    2008-01-01

    In this research, new physical fission reactor parameters which have very sensitive effects on the qualitative behavior of a reactor, are introduced. Therefore, the two, the nonlinear dynamics of two, three and four dimensional, considering almost the effective parameters are formulated for describing nuclear fission reactor systems. Using both analytical and numerical methods, the stability and instability of the given dynamical equations and the conditions of stability are studied in these systems. We have shown that the two parameters of the mean energy residence time in fuel and coolant and also their ratios have the most qualitative effects on the dynamical behaviour of a typical nuclear fission reactor. Increasing or decreasing of these parameters from a captain limit can lead to stability or un stability in a given system

  6. Dynamic behaviour and shock-induced martensite transformation in near-beta Ti-5553 alloy under high strain rate loading

    Directory of Open Access Journals (Sweden)

    Wang Lin

    2015-01-01

    Full Text Available Ti-5553 alloy is a near-beta titanium alloy with high strength and high fracture toughness. In this paper, the dynamic behaviour and shock-induced martensite phase transformation of Ti-5553 alloy with alpha/beta phases were investigated. Split Hopkinson Pressure Bar was employed to investigate the dynamic properties. Microstructure evolutions were characterized by Scanning Electronic Microscopy and Transmission Electron Microscope. The experimental results have demonstrated that Ti-5553 alloy with alpha/beta phases exhibits various strain rate hardening effects, both failure through adiabatic shear band. Ti-5553 alloy with Widmannstatten microstructure exhibit more obvious strain rate hardening effect, lower critical strain rate for ASB nucleation, compared with the alloy with Bimodal microstructures. Under dynamic compression, shock-induced beta to alpha” martensite transformation occurs.

  7. Transportation behaviour of fluopicolide and its control effect against Phytophthora capsici in greenhouse tomatoes after soil application.

    Science.gov (United States)

    Jiang, Lili; Wang, Hongyan; Xu, Hui; Qiao, Kang; Xia, Xiaoming; Wang, Kaiyun

    2015-07-01

    Fluopicolide, a novel benzamide fungicide, was registered for control of oomycete pathogens, including Phytophthora capsici. In this study, fluopicolide (5% SC) was applied in soil at rates of 1.5, 3 and 6 L ha(-1) [the normal (ND), double (DD) and quadruple dosages (QD) respectively] to investigate its transportation behaviour and control efficiency on tomato blight as a soil treatment agent. The results showed that fluopicolide applied to soil could be absorbed by tomato roots and then transplanted to stems and leaves. It could exist in tomato roots for more than 30 days, and in leaves and stems until day 20 after application. The decline in fluopicolide in soil was in accordance with a first-order dynamics equation, with half-lives of 5.33, 4.75 and 5.42 days for the ND, DD and QD treatments respectively. The control efficiencies of fluopicolide were better with soil application than with spraying application, and the inhibition ratios were 93.02, 97.67 and 100 on day 21 for the ND, DD and QD treatments respectively. Soil application of fluopicolide could control P. capsici in greenhouse tomatoes with high efficiency and long persistence. © 2014 Society of Chemical Industry.

  8. Dynamical model of birdsong maintenance and control

    Science.gov (United States)

    Abarbanel, Henry D. I.; Talathi, Sachin S.; Mindlin, Gabriel; Rabinovich, Misha; Gibb, Leif

    2004-11-01

    The neuroethology of song learning, production, and maintenance in songbirds presents interesting similarities to human speech. We have developed a biophysical model of the manner in which song could be maintained in adult songbirds. This model may inform us about the human counterpart to these processes. In songbirds, signals generated in nucleus High Vocal center (HVc) follow a direct route along a premotor pathway to the robust nucleus of the archistriatum (RA) as well as an indirect route to RA through the anterior forebrain pathway (AFP): the neurons of RA are innervated from both sources. HVc expresses very sparse bursts of spikes having interspike intervals of about 2ms . The expressions of these bursts arrive at the RA with a time difference ΔT≈50±10ms between the two pathways. The observed combination of AMPA and NMDA receptors at RA projection neurons suggests that long-term potentiation and long-term depression can both be induced by spike timing plasticity through the pairing of the HVc and AFP signals. We present a dynamical model that stabilizes this synaptic plasticity through a feedback from the RA to the AFP using known connections. The stabilization occurs dynamically and is absent when the RA→AFP connection is removed. This requires a dynamical selection of ΔT . The model does this, and ΔT lies within the observed range. Our model represents an illustration of a functional consequence of activity-dependent plasticity directly connected with neuroethological observations. Within the model the parameters of the AFP, and thus the magnitude of ΔT , can also be tuned to an unstable regime. This means that destabilization might be induced by neuromodulation of the AFP.

  9. Analysis and control of complex dynamical systems robust bifurcation, dynamic attractors, and network complexity

    CERN Document Server

    Imura, Jun-ichi; Ueta, Tetsushi

    2015-01-01

    This book is the first to report on theoretical breakthroughs on control of complex dynamical systems developed by collaborative researchers in the two fields of dynamical systems theory and control theory. As well, its basic point of view is of three kinds of complexity: bifurcation phenomena subject to model uncertainty, complex behavior including periodic/quasi-periodic orbits as well as chaotic orbits, and network complexity emerging from dynamical interactions between subsystems. Analysis and Control of Complex Dynamical Systems offers a valuable resource for mathematicians, physicists, and biophysicists, as well as for researchers in nonlinear science and control engineering, allowing them to develop a better fundamental understanding of the analysis and control synthesis of such complex systems.

  10. Robot Control for Dynamic Environment Using Vision and Autocalibration

    DEFF Research Database (Denmark)

    Larsen, Thomas Dall; Lildballe, Jacob; Andersen, Nils Axel

    1997-01-01

    To enhance flexibility and extend the area of applications for robotic systems, it is important that the systems are capable ofhandling uncertainties and respond to (random) human behaviour.A vision systemmust very often be able to work in a dynamical ``noisy'' world where theplacement ofobjects...... can vary within certain restrictions. Furthermore it would be useful ifthe system is able to recover automatically after serious changes have beenapplied, for instance if the camera has been moved.In this paper an implementationof such a system is described. The system is a robotcapable of playing...

  11. Kinematics and Dynamics of Motion Control Based on Acceleration Control

    Science.gov (United States)

    Ohishi, Kiyoshi; Ohba, Yuzuru; Katsura, Seiichiro

    The first IEEE International Workshop on Advanced Motion Control was held in 1990 pointed out the importance of physical interpretation of motion control. The software servoing technology is now common in machine tools, robotics, and mechatronics. It has been intensively developed for the numerical control (NC) machines. Recently, motion control in unknown environment will be more and more important. Conventional motion control is not always suitable due to the lack of adaptive capability to the environment. A more sophisticated ability in motion control is necessary for compliant contact with environment. Acceleration control is the key technology of motion control in unknown environment. The acceleration control can make a motion system to be a zero control stiffness system without losing the robustness. Furthermore, a realization of multi-degree-of-freedom motion is necessary for future human assistance. A human assistant motion will require various control stiffness corresponding to the task. The review paper focuses on the modal coordinate system to integrate the various control stiffness in the virtual axes. A bilateral teleoperation is a good candidate to consider the future human assistant motion and integration of decentralized systems. Thus the paper reviews and discusses the bilateral teleoperation from the control stiffness and the modal control design points of view.

  12. Emergent adaptive behaviour of GRN-controlled simulated robots in a changing environment

    Directory of Open Access Journals (Sweden)

    Yao Yao

    2016-12-01

    Full Text Available We developed a bio-inspired robot controller combining an artificial genome with an agent-based control system. The genome encodes a gene regulatory network (GRN that is switched on by environmental cues and, following the rules of transcriptional regulation, provides output signals to actuators. Whereas the genome represents the full encoding of the transcriptional network, the agent-based system mimics the active regulatory network and signal transduction system also present in naturally occurring biological systems. Using such a design that separates the static from the conditionally active part of the gene regulatory network contributes to a better general adaptive behaviour. Here, we have explored the potential of our platform with respect to the evolution of adaptive behaviour, such as preying when food becomes scarce, in a complex and changing environment and show through simulations of swarm robots in an A-life environment that evolution of collective behaviour likely can be attributed to bio-inspired evolutionary processes acting at different levels, from the gene and the genome to the individual robot and robot population.

  13. Emergent adaptive behaviour of GRN-controlled simulated robots in a changing environment.

    Science.gov (United States)

    Yao, Yao; Storme, Veronique; Marchal, Kathleen; Van de Peer, Yves

    2016-01-01

    We developed a bio-inspired robot controller combining an artificial genome with an agent-based control system. The genome encodes a gene regulatory network (GRN) that is switched on by environmental cues and, following the rules of transcriptional regulation, provides output signals to actuators. Whereas the genome represents the full encoding of the transcriptional network, the agent-based system mimics the active regulatory network and signal transduction system also present in naturally occurring biological systems. Using such a design that separates the static from the conditionally active part of the gene regulatory network contributes to a better general adaptive behaviour. Here, we have explored the potential of our platform with respect to the evolution of adaptive behaviour, such as preying when food becomes scarce, in a complex and changing environment and show through simulations of swarm robots in an A-life environment that evolution of collective behaviour likely can be attributed to bio-inspired evolutionary processes acting at different levels, from the gene and the genome to the individual robot and robot population.

  14. Emergent adaptive behaviour of GRN-controlled simulated robots in a changing environment

    Science.gov (United States)

    Yao, Yao; Storme, Veronique; Marchal, Kathleen

    2016-01-01

    We developed a bio-inspired robot controller combining an artificial genome with an agent-based control system. The genome encodes a gene regulatory network (GRN) that is switched on by environmental cues and, following the rules of transcriptional regulation, provides output signals to actuators. Whereas the genome represents the full encoding of the transcriptional network, the agent-based system mimics the active regulatory network and signal transduction system also present in naturally occurring biological systems. Using such a design that separates the static from the conditionally active part of the gene regulatory network contributes to a better general adaptive behaviour. Here, we have explored the potential of our platform with respect to the evolution of adaptive behaviour, such as preying when food becomes scarce, in a complex and changing environment and show through simulations of swarm robots in an A-life environment that evolution of collective behaviour likely can be attributed to bio-inspired evolutionary processes acting at different levels, from the gene and the genome to the individual robot and robot population. PMID:28028477

  15. Handbook of electrical power system dynamics modeling, stability, and control

    CERN Document Server

    Eremia, Mircea

    2013-01-01

    Complete guidance for understanding electrical power system dynamics and blackouts This handbook offers a comprehensive and up-to-date treatment of power system dynamics. Addressing the full range of topics, from the fundamentals to the latest technologies in modeling, stability, and control, Handbook of Electrical Power System Dynamics provides engineers with hands-on guidance for understanding the phenomena leading to blackouts so they can design the most appropriate solutions for a cost-effective and reliable operation. Focusing on system dynamics, the book details

  16. Entrepreneurship education revisited: perceived entrepreneurial role models increase perceived behavioural control

    Science.gov (United States)

    Fellnhofer, Katharina

    2017-01-01

    Relying on Bandura’s (1986) social learning theory, Ajzen’s (1988) theory of planned behaviour (TPB), and Dyer’s (1994) model of entrepreneurial careers, this study aims to highlight the potential of entrepreneurial role models to entrepreneurship education. The results suggest that entrepreneurial courses would greatly benefit from real-life experiences, either positive or negative. The results of regression analysis based on 426 individuals, primarily from Austria, Finland, and Greece, show that role models increase learners’ entrepreneurial perceived behaviour control (PBC) by increasing their self-efficacy. This study can inform the research and business communities and governments about the importance of integrating entrepreneurs into education to stimulate entrepreneurial PBC. This study is the first of its kind using its approach, and its results warrant more in-depth studies of storytelling by entrepreneurial role models in the context of multimedia entrepreneurship education. PMID:29104604

  17. Entrepreneurship education revisited: perceived entrepreneurial role models increase perceived behavioural control.

    Science.gov (United States)

    Fellnhofer, Katharina

    2017-01-01

    Relying on Bandura's (1986) social learning theory, Ajzen's (1988) theory of planned behaviour (TPB), and Dyer's (1994) model of entrepreneurial careers, this study aims to highlight the potential of entrepreneurial role models to entrepreneurship education. The results suggest that entrepreneurial courses would greatly benefit from real-life experiences, either positive or negative. The results of regression analysis based on 426 individuals, primarily from Austria, Finland, and Greece, show that role models increase learners' entrepreneurial perceived behaviour control (PBC) by increasing their self-efficacy. This study can inform the research and business communities and governments about the importance of integrating entrepreneurs into education to stimulate entrepreneurial PBC. This study is the first of its kind using its approach, and its results warrant more in-depth studies of storytelling by entrepreneurial role models in the context of multimedia entrepreneurship education.

  18. Fuzzy controller for an uncertain dynamical system

    DEFF Research Database (Denmark)

    Kulczycki, P.; Wisniewski, Rafal

    2002-01-01

    The present paper deals with the time-optimal control for mechanical systems with uncertain load. A fuzzy approach is used in the design of suboptimal feedback controllers, robust with respect to the load. Statistical kernel estimators are used for the specification of crucial parameters. The met......The present paper deals with the time-optimal control for mechanical systems with uncertain load. A fuzzy approach is used in the design of suboptimal feedback controllers, robust with respect to the load. Statistical kernel estimators are used for the specification of crucial parameters....... The methodology proposed in this work may be easily adopted to other modeling uncertainties of mechanical systems, e.g. motion resistance....

  19. Dynamic flow control strategies of vehicle SCR Urea Dosing System

    Science.gov (United States)

    Lin, Wei; Zhang, Youtong; Asif, Malik

    2015-03-01

    Selective Catalyst Reduction(SCR) Urea Dosing System(UDS) directly affects the system accuracy and the dynamic response performance of a vehicle. However, the UDS dynamic response is hard to keep up with the changes of the engine's operating conditions. That will lead to low NO X conversion efficiency or NH3 slip. In order to optimize the injection accuracy and the response speed of the UDS in dynamic conditions, an advanced control strategy based on an air-assisted volumetric UDS is presented. It covers the methods of flow compensation and switching working conditions. The strategy is authenticated on an UDS and tested in different dynamic conditions. The result shows that the control strategy discussed results in higher dynamic accuracy and faster dynamic response speed of UDS. The inject deviation range is improved from being between -8% and 10% to -4% and 2% and became more stable than before, and the dynamic response time was shortened from 200 ms to 150 ms. The ETC cycle result shows that after using the new strategy the NH3 emission is reduced by 60%, and the NO X emission remains almost unchanged. The trade-off between NO X conversion efficiency and NH3 slip is mitigated. The studied flow compensation and switching working conditions can improve the dynamic performance of the UDS significantly and make the UDS dynamic response keep up with the changes of the engine's operating conditions quickly.

  20. Controlling chaos in dynamical systems described by maps

    International Nuclear Information System (INIS)

    Crispin, Y.; Marduel, C.

    1994-01-01

    The problem of suppressing chaotic behavior in dynamical systems is treated using a feedback control method with limited control effort. The proposed method is validated on archetypal systems described by maps, i.e. discrete-time difference equations. The method is also applicable to dynamical systems described by flows, i.e. by systems of ordinary differential equations. Results are presented for the one-dimensional logistic map and for a two-dimensional Lotka-Volterra map describing predator-prey population dynamics. It is shown that chaos can be suppressed and the system stabilized about a period-1 fixed point of the maps

  1. Dynamic behaviour of Bose-Einstein condensates in optical lattices with two- and three-body interactions

    International Nuclear Information System (INIS)

    Chen Yan; Chen Yong; Zhang Kezhi

    2009-01-01

    We study the dynamic behaviour of Bose-Einstein condensates with two- and three-atom interactions in optical lattices with analytical and numerical methods. It is found that the steady-state relative population displays tuning-fork bifurcation when the system parameters are changed to certain critical values. In particular, the existence of the three-body interaction not only transforms the bifurcation point of the system but also greatly affects the macroscopic quantum self-trapping behaviours associated with the critically stable steady-state solution. In addition, we investigated the influence of the initial conditions, three-body interaction, and the energy bias on the macroscopic quantum self-trapping. Finally, by applying the periodic modulation on the energy bias, we observed that the relative population oscillation exhibits a process from order to chaos, via a series of period-doubling bifurcations.

  2. A Conceptual framework of Strategy, Structure and Innovative Behaviour for the Development of a Dynamic Simulation Model

    Science.gov (United States)

    Konstantopoulos, Nikolaos; Trivellas, Panagiotis; Reklitis, Panagiotis

    2007-12-01

    According to many researchers of organizational theory, a great number of problems encountered by the manufacturing firms are due to their failure to foster innovative behaviour by aligning business strategy and structure. From this point of view, the fit between strategy and structure is essential in order to facilitate firms' innovative behaviour. In the present paper, we adopt Porter's typology to operationalise business strategy (cost leadership, innovative and marketing differentiation, and focus). Organizational structure is built on four dimensions (centralization, formalization, complexity and employees' initiatives to implement new ideas). Innovativeness is measured as product innovation, process and technological innovation. This study provides the necessary theoretical framework for the development of a dynamic simulation method, although the simulation of social events is a quite difficult task, considering that there are so many alternatives (not all well understood).

  3. Phase-space dynamics of opposition control in wall-bounded turbulent flows

    Science.gov (United States)

    Hwang, Yongyun; Ibrahim, Joseph; Yang, Qiang; Doohan, Patrick

    2017-11-01

    The phase-space dynamics of wall-bounded shear flow in the presence of opposition control is explored by examining the behaviours of a pair of nonlinear equilibrium solutions (exact coherent structures), edge state and life time of turbulence at low Reynolds numbers. While the control modifies statistics and phase-space location of the edge state and the lower-branch equilibrium solution very little, it is also found to regularise the periodic orbit on the edge state by reverting a period-doubling bifurcation. Only the upper-branch equilibrium solution and mean turbulent state are significantly modified by the control, and, in phase space, they gradually approach the edge state on increasing the control gain. It is found that this behaviour results in a significant reduction of the life time of turbulence, indicating that the opposition control significantly increases the probability that the turbulent solution trajectory passes through the edge state. Finally, it is shown that the opposition control increases the critical Reynolds number of the onset of the equilibrium solutions, indicating its capability of transition delay. This work is sponsored by the Engineering and Physical Sciences Research Council (EPSRC) in the UK (EP/N019342/1).

  4. Kinetic models for crowd dynamics. Comment on "Human behaviours in evacuation crowd dynamics: From modelling to "big data" toward crisis management" by N. Bellomo et al.

    Science.gov (United States)

    Banasiak, J.

    2016-09-01

    There has been a hierarchy of models of crowd behaviour. One can consider the crowd at the so called microscopic level, as a collection of individuals, and derive its description in the form of a (large) system of ordinary differential equations describing the position and velocity of each individual, in parallel to the Newton's description of matter, see e.g. [10]. Another possibility is to describe crowd, in analogy to fluid dynamics, by providing its density and velocity at a given point, see e.g. [11,12]. At the same time, it is recognized that crowd is 'living, social' system that is prone to exhibit rare, not easily predictable, behaviour in response to stress induced by the perception of danger, or of the action of specific agents, see e.g. [1,2]. This high probability of the occurrence of events that are far from average, makes the crowd behaviour similar to the processes with fat-tailed distribution of events. Such unlikely events have been metaphorically termed black swans in [14], or Lévy flights in [13]. While microscopic and macroscopic models can capture many features of crowd dynamics, including obstacles, see [3,8], such models are described by differential equations that inherently are local in space. At the same time, black swan events are often caused by non-local interactions such as self-organization, learning or adherence to some averaged group behaviour. It is known that such interactions are well described by mean field models best represented by integro-differential equations, such as the Boltzmann equation of the rarefied gas theory. This has made plausible to introduce crowd models at the intermediate, (meso) scale by describing the crowd by the one particle distribution function that gives the density of individuals at any particular state; that is, at a given point in the domain and moving with a specific velocity.

  5. Complex systems and networks dynamics, controls and applications

    CERN Document Server

    Yu, Xinghuo; Chen, Guanrong; Yu, Wenwu

    2016-01-01

    This elementary book provides some state-of-the-art research results on broad disciplinary sciences on complex networks. It presents an in-depth study with detailed description of dynamics, controls and applications of complex networks. The contents of this book can be summarized as follows. First, the dynamics of complex networks, for example, the cluster dynamic analysis by using kernel spectral methods, community detection algorithms in bipartite networks, epidemiological modeling with demographics and epidemic spreading on multi-layer networks, are studied. Second, the controls of complex networks are investigated including topics like distributed finite-time cooperative control of multi-agent systems by applying homogenous-degree and Lyapunov methods, composite finite-time containment control for disturbed second-order multi-agent systems, fractional-order observer design of multi-agent systems, chaos control and anticontrol of complex systems via Parrondos game and many more. Third, the applications of ...

  6. Mediation effect of perceived behavioural control on intended condom use: applicability of the theory of planned behaviour to money boys in China.

    Science.gov (United States)

    Liu, Hongjie; Kennedy, May; Liu, Hui; Hong, Fuchang; Ha, Toan; Ning, Zheng

    2013-12-01

    Money boys (MBs) are male sex workers who sell sex to men who have sex with men. The objectives of this study were to assess (a) the sexual HIV risk of MBs; (b) the ability of the theory of planned behaviour (TPB) to predict MBs' intentions to use condoms; and (c) the manner in which TPB constructs (attitudes towards condom use, subjective norms and perceived behavioural control) combine to influence condom use intentions. Participants came from 10 MB-frequented clubs in two cities in China. Multiple regression and path analytic models were used to test inter-relationships among the TPB constructs. Seventy-eight percent of the 122 MB participants reported having used condoms for every anal sex act. About one-third reported having had female sexual partners in the past 2 months; of these MBs, half (53%) used condoms for every sex act. A revised model using TPB constructs accounted for 52% of the variance of condom use intentions and revealed that perceived behavioural control was a mediator in pathways beginning with attitudes and ending with condom use intentions, and beginning with subjective norms and ending with intentions. The findings suggest that a revised model of TPB applies to condom use intentions among Chinese MBs. It may be appropriate to adapt HIV interventions that are grounded in TPB and that have been shown to be effective elsewhere for use with Chinese MBs. HIV interventions for this population should give perceived behavioural control and its predictors special consideration.

  7. Performance, Career Dynamics, and Span of Control

    DEFF Research Database (Denmark)

    Smeets, Valerie Anne Rolande; Waldman, Michael; Warzynski, Frederic Michel Patrick

    that higher ability managers should supervise more subordinates, or equivalently, have a larger span of control. And although some of this theory’s predictions have been empirically investigated, there has been little systematic investigation of the theory’s predictions concerning span of control....... In this paper we first extend the theoretical literature on the scale-of-operations effect to allow firms’ beliefs concerning a manager’s ability to evolve over the manager’s career, where much of our focus is the determinants of span of control. We then empirically investigate testable predictions from......There is an extensive theoretical literature based on what is called the scale-of-operations effect, i.e., the idea that the return to managerial ability is higher the more resources the manager influences with his or her decisions. This idea leads to various testable predictions including...

  8. Dynamic Control of Airport Departures: Algorithm Development and Field Evaluation

    OpenAIRE

    Simaiakis, Ioannis; Balakrishnan, Hamsa

    2012-01-01

    Surface congestion leads to significant increases in taxi times and fuel burn at major airports. In this paper, we formulate the airport surface congestion management problem as a dynamic control problem. We address two main challenges: the random delay between actuation (at the gate) and the server being controlled (the runway), and the need to develop control strategies that can be implemented in practice by human air traffic controllers. The second requirement necessitates a strategy that ...

  9. Yaw control for active damping of structural dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Ekelund, T. [Chalmers Univ. of Technology, Goeteborg (Sweden). Control Engineering Lab.

    1996-12-01

    Yaw torque control for reduction of structural dynamic loads in a two-bladed wind turbine is investigated. The models are obtained using rigid-body mechanics. Linear quadratic control theory is utilized for design and analysis. The analysis of two simple examples, where the teeter angle and the tower lateral bending motion are regarded, shows that a time-varying controller has some advantages compared with a time-invariant controller. 6 refs, 9 figs

  10. Feedback Linearized Aircraft Control Using Dynamic Cell Structure

    Science.gov (United States)

    Jorgensen, C. C.

    1998-01-01

    A Dynamic Cell Structure (DCS ) Neural Network was developed which learns a topology representing network (TRN) of F-15 aircraft aerodynamic stability and control derivatives. The network is combined with a feedback linearized tracking controller to produce a robust control architecture capable of handling multiple accident and off-nominal flight scenarios. This paper describes network and its performance for accident scenarios including differential stabilator lock, soft sensor failure, control, stability derivative variation, and turbulence.

  11. Dynamic performance enhancement of microgrids by advanced sliding mode controller

    Energy Technology Data Exchange (ETDEWEB)

    Sofla, Mohammadhassan Abdollahi [Electrical Engineering and Computer Science Dept., University of Toledo, Ohio (United States); Gharehpetian, Gevorg B. [Electrical Engineering Dept., Amirkabir University of Technology, Tehran (Iran, Islamic Republic of)

    2011-01-15

    Dynamics are the most important problems in the microgrid operation. In the islanded microgrid, the mismatch of parallel operations of inverters during dynamics can result in the instability. This paper considers severe dynamics which can occur in the microgrid. Microgrid can have different configurations with different load and generation dynamics which are facing voltage disturbances. As a result, microgrid has many uncertainties and is placed in the distribution network where is full of voltage disturbances. Moreover, characteristics of the distribution network and distributed energy resources in the islanded mode make microgrid vulnerable and easily lead to instability. The main aim of this paper is to discuss the suitable mathematical modeling based on microgrid characteristics and to design properly inner controllers to enhance the dynamics of microgrid with uncertain and changing parameters. This paper provides a method for inner controllers of inverter-based distributed energy resources to have a suitable response for different dynamics. Parallel inverters in distribution networks were considered to be controlled by nonlinear robust voltage and current controllers. Theoretical prove beyond simulation results, reveal evidently the effectiveness of the proposed controller. (author)

  12. Dedicated EGR engine with dynamic load control

    Science.gov (United States)

    Hayman, Alan W.; McAlpine, Robert S.; Keating, Edward J.

    2016-09-06

    An internal combustion engine comprises a first engine bank and a second engine bank. A first intake valve is disposed in an intake port of a cylinder of the first engine bank, and is configured for metering the first flow of combustion air by periodically opening and closing according to a first intake valve lift and duration characteristic. A variable valve train control mechanism is configured for affecting the first intake valve lift and duration characteristic. Either a lift or duration of the first intake valve is modulated so as to satisfy an EGR control criterion.

  13. Solar Dynamic Power System Stability Analysis and Control

    Science.gov (United States)

    Momoh, James A.; Wang, Yanchun

    1996-01-01

    The objective of this research is to conduct dynamic analysis, control design, and control performance test of solar power system. Solar power system consists of generation system and distribution network system. A bench mark system is used in this research, which includes a generator with excitation system and governor, an ac/dc converter, six DDCU's and forty-eight loads. A detailed model is used for modeling generator. Excitation system is represented by a third order model. DDCU is represented by a seventh order system. The load is modeled by the combination of constant power and constant impedance. Eigen-analysis and eigen-sensitivity analysis are used for system dynamic analysis. The effects of excitation system, governor, ac/dc converter control, and the type of load on system stability are discussed. In order to improve system transient stability, nonlinear ac/dc converter control is introduced. The direct linearization method is used for control design. The dynamic analysis results show that these controls affect system stability in different ways. The parameter coordination of controllers are recommended based on the dynamic analysis. It is concluded from the present studies that system stability is improved by the coordination of control parameters and the nonlinear ac/dc converter control stabilize system oscillation caused by the load change and system fault efficiently.

  14. Can training improve laypersons helping behaviour in first aid? A randomised controlled deception trial.

    Science.gov (United States)

    Van de Velde, Stijn; Roex, Ann; Vangronsveld, Karoline; Niezink, Lidewij; Van Praet, Koen; Heselmans, Annemie; Donceel, Peter; Vandekerckhove, Philippe; Ramaekers, Dirk; Aertgeerts, Bert

    2013-04-01

    There is limited evidence indicating that laypersons trained in first aid provide better help, but do not help more often than untrained laypersons. This study investigated the effect of conventional first aid training versus conventional training plus supplementary training aimed at decreasing barriers to helping. The authors conducted a randomised controlled trial. After 24 h of conventional first aid training, the participants either attended an experimental lesson to reduce barriers to helping or followed a control lesson. The authors used a deception test to measure the time between the start of the unannounced simulated emergency and seeking help behaviour and the number of particular helping actions. The authors randomised 72 participants to both groups. 22 participants were included in the analysis for the experimental group and 36 in the control group. The authors found no statistically or clinically significant differences for any of the outcome measures. The time until seeking help (geometrical mean and 95% CI) was 55.5 s (42.9 to 72.0) in the experimental group and 56.5 s (43.0 to 74.3) in the control group. 57% of the participants asked a bystander to seek help, 40% left the victim to seek help themselves and 3% did not seek any help. Supplementary training on dealing with barriers to helping did not alter the helping behaviour. The timing and appropriateness of the aid provided can be improved. The authors registered this trial at ClinicalTrials.gov as NCT00954161.

  15. Motion behaviour of magneto-sensitive elastomers controlled by an external magnetic field for sensor applications

    Energy Technology Data Exchange (ETDEWEB)

    Volkova, T.I., E-mail: tatiana.volkova@tu-ilmenau.de [Technische Universität Ilmenau, Faculty of Mechanical Engineering, Technical Mechanics Group, D-98693 Ilmenau (Germany); Böhm, V., E-mail: valter.boehm@tu-ilmenau.de [Technische Universität Ilmenau, Faculty of Mechanical Engineering, Technical Mechanics Group, D-98693 Ilmenau (Germany); Kaufhold, T., E-mail: tobias.kaufhold@tu-ilmenau.de [Technische Universität Ilmenau, Faculty of Mechanical Engineering, Technical Mechanics Group, D-98693 Ilmenau (Germany); Popp, J., E-mail: jana.popp@tu-ilmenau.de [Technische Universität Ilmenau, Faculty of Mechanical Engineering, Technical Mechanics Group, D-98693 Ilmenau (Germany); Becker, F., E-mail: felix.becker@tu-ilmenau.de [Technische Universität Ilmenau, Faculty of Mechanical Engineering, Technical Mechanics Group, D-98693 Ilmenau (Germany); Borin, D.Yu., E-mail: dmitry.borin@tu-dresden.de [Technische Universität Dresden, Magnetofluiddynamics, Measuring and Automation Technology, D-01062 Dresden (Germany); Stepanov, G.V., E-mail: gstepanov@mail.ru [State Institute of Chemistry and Technology of Organoelement Compounds, 105118 Moscow (Russian Federation); Zimmermann, K., E-mail: klaus.zimmermann@tu-ilmenau.de [Technische Universität Ilmenau, Faculty of Mechanical Engineering, Technical Mechanics Group, D-98693 Ilmenau (Germany)

    2017-06-01

    The development of sensor systems with a complex adaptive regulation of the operating sensitivity and behaviour is an actual scientific and technical challenge. Smart materials like magneto-sensitive elastomers (MSE) are seen as one potential solution for this problem, since their mechanical properties may be controlled by external magnetic fields. The present paper deals with the investigation of elastic and damping properties of MSE containing magnetically soft particles under the influence of a uniform magnetic field. Based on the measurement of the first eigenfrequency of free bending vibrations of a fixed beam, the effective Young's modulus is evaluated theoretically and also numerically using Finite Element Method. It is shown that this parameter, as well as the first eigenfrequency of the beam, increases monotonically with the magnitude of the applied magnetic field. The results are aimed to develop an acceleration sensor with adaptive magnetically controllable sensitivity range for the detection of external mechanical stimuli of the environment. - Highlights: • The motion behaviour of magneto-sensitive elastomers (MSE) with magnetically soft particles is investigated. • The first eigenfrequency of free bending vibrations of an MSE beam can be controlled by a uniform magnetic field. • Based on the experimental results, the effective Young's modulus of the system is evaluated theoretically and numerically. • The Young's modulus increases monotonically with the magnitude of the applied magnetic field. • The controlled mechanical compliance of MSE may be used for development of sensor systems with adaptive sensitivity range.

  16. Parameters control in GAs for dynamic optimization

    Directory of Open Access Journals (Sweden)

    Khalid Jebari

    2013-02-01

    Full Text Available The Control of Genetic Algorithms parameters allows to optimize the search process and improves the performance of the algorithm. Moreover it releases the user to dive into a game process of trial and failure to find the optimal parameters.

  17. Neural network based adaptive control for nonlinear dynamic regimes

    Science.gov (United States)

    Shin, Yoonghyun

    Adaptive control designs using neural networks (NNs) based on dynamic inversion are investigated for aerospace vehicles which are operated at highly nonlinear dynamic regimes. NNs play a key role as the principal element of adaptation to approximately cancel the effect of inversion error, which subsequently improves robustness to parametric uncertainty and unmodeled dynamics in nonlinear regimes. An adaptive control scheme previously named 'composite model reference adaptive control' is further developed so that it can be applied to multi-input multi-output output feedback dynamic inversion. It can have adaptive elements in both the dynamic compensator (linear controller) part and/or in the conventional adaptive controller part, also utilizing state estimation information for NN adaptation. This methodology has more flexibility and thus hopefully greater potential than conventional adaptive designs for adaptive flight control in highly nonlinear flight regimes. The stability of the control system is proved through Lyapunov theorems, and validated with simulations. The control designs in this thesis also include the use of 'pseudo-control hedging' techniques which are introduced to prevent the NNs from attempting to adapt to various actuation nonlinearities such as actuator position and rate saturations. Control allocation is introduced for the case of redundant control effectors including thrust vectoring nozzles. A thorough comparison study of conventional and NN-based adaptive designs for a system under a limit cycle, wing-rock, is included in this research, and the NN-based adaptive control designs demonstrate their performances for two highly maneuverable aerial vehicles, NASA F-15 ACTIVE and FQM-117B unmanned aerial vehicle (UAV), operated under various nonlinearities and uncertainties.

  18. Increased risk of impulse control symptoms in Parkinson's disease with REM sleep behaviour disorder.

    Science.gov (United States)

    Fantini, M L; Macedo, L; Zibetti, M; Sarchioto, M; Vidal, T; Pereira, B; Marques, A; Debilly, B; Derost, P; Ulla, M; Vitello, N; Cicolin, A; Lopiano, L; Durif, F

    2015-02-01

    To assess the frequency of symptoms of impulse control disorders (ICD, namely pathological gambling, compulsive sexual behaviour, compulsive eating and compulsive shopping) and related behaviours (hobbyism, punding, walkabout and dopamine dysregulation syndrome) in patients with Parkinson's disease (PD) with and without probable rapid eye movement, sleep behaviour disorder (pRBD). Two hundred and sixteen consecutive PD patients, attending two university-based movement disorders clinics, were screened for p-RBD using the RBD Single Question and the RBD Screening Questionnaire (RBDSQ). Current ICDs and related behaviours symptoms were assessed with the Questionnaire for Impulsive-Compulsive Disorders in PD (QUIP)-short form. PD-pRBD patients (n=106/216;49%) had a longer PD duration, a higher Hoehn & Yahr score, a greater levodopa-equivalent daily dose (LEDD), but no difference in dopamine agonist use, compared to PD-without pRBD. A higher proportion of one or more current ICDs and related behaviours symptoms was reported in PD-pRBD compared to PD-without RBD (53% vs28%; p=0.0002). In a multivariate regression analysis accounting for gender, age of onset, PD duration, PD severity, depression score and total and dopaminergic agonist-LEDD, RBD was associated to a relative risk of 1.84 for any ICD or related behaviours symptoms (p=0.01), and to a risk of 2.59 for any ICD symptoms only (p=0.001). Furthermore, PD-pRBD had a more than fourfold risk for symptoms of pathological gambling (relative risk (RR): 4.87; p=0.049) compared to PD-without pRBD. The present study indicates that RBD is associated with an increased risk of developing symptoms of ICDs in PD. Identifying RBD in PD may help clinicians to choose the best therapeutic strategy. AU1023 Institutional Ethics Committee. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  19. Cost and Outcome of BehaviouRal Activation (COBRA): a randomised controlled trial of behavioural activation versus cognitive-behavioural therapy for depression.

    Science.gov (United States)

    Richards, David A; Rhodes, Shelley; Ekers, David; McMillan, Dean; Taylor, Rod S; Byford, Sarah; Barrett, Barbara; Finning, Katie; Ganguli, Poushali; Warren, Fiona; Farrand, Paul; Gilbody, Simon; Kuyken, Willem; O'Mahen, Heather; Watkins, Ed; Wright, Kim; Reed, Nigel; Fletcher, Emily; Hollon, Steven D; Moore, Lucy; Backhouse, Amy; Farrow, Claire; Garry, Julie; Kemp, Deborah; Plummer, Faye; Warner, Faith; Woodhouse, Rebecca

    2017-08-01

    Depression is a common, debilitating and costly disorder. The best-evidenced psychological therapy - cognitive-behavioural therapy (CBT) - is complex and costly. A simpler therapy, behavioural activation (BA), may be an effective alternative. To determine the clinical effectiveness and cost-effectiveness of BA compared with CBT for depressed adults at 12 and 18 months' follow-up, and to investigate the processes of treatments. Randomised controlled, non-inferiority trial stratified by depression severity, antidepressant use and recruitment site, with embedded process evaluation; and randomisation by remote computer-generated allocation. Three community mental health services in England. Adults aged ≥ 18 years with major depressive disorder (MDD) recruited from primary care and psychological therapy services. BA delivered by NHS junior mental health workers (MHWs); CBT by NHS psychological therapists. Primary: depression severity (as measured via the Patient Health Questionnaire-9; PHQ-9) at 12 months. Secondary: MDD status; number of depression-free days; anxiety (as measured via the Generalised Anxiety Disorder-7); health-related quality of life (as measured via the Short Form questionnaire-36 items) at 6, 12 and 18 months; and PHQ-9 at 6 and 18 months, all collected by assessors blinded to treatment allocation. Non-inferiority margin was 1.9 PHQ-9 points. We undertook intention-to-treat (ITT) and per protocol (PP) analyses. We explored cost-effectiveness by collecting direct treatment and other health- and social-care costs and calculating quality-adjusted life-years (QALYs) using the EuroQol-5 Dimensions, three-level version, at 18 months. We recruited 440 participants (BA, n  = 221; CBT, n  = 219); 175 (79%) BA and 189 (86%) CBT participants provided ITT data and 135 (61%) BA and 151 (69%) CBT participants provided PP data. At 12 months we found that BA was non-inferior to CBT {ITT: CBT 8.4 PHQ-9 points [standard deviation (SD) 7.5 PHQ-9 points], BA

  20. Towards changing healthcare workers' behaviour: a qualitative study exploring non-compliance through appraisals of infection prevention and control practices.

    Science.gov (United States)

    Shah, N; Castro-Sánchez, E; Charani, E; Drumright, L N; Holmes, A H

    2015-06-01

    Improving behaviour in infection prevention and control (IPC) practice remains a challenge, and understanding the determinants of healthcare workers' (HCWs) behaviour is fundamental to develop effective and sustained behaviour change interventions. To identify behaviours of HCWs that facilitated non-compliance with IPC practices, focusing on how appraisals of IPC duties and social and environmental circumstances shaped and influenced non-compliant behaviour. This study aimed to: (1) identify how HCWs rationalized their own behaviour and the behaviour of others; (2) highlight challenging areas of IPC compliance; and (3) describe the context of the working environment that may explain inconsistencies in IPC practices. Clinical staff at a National Health Service hospital group in London, UK were interviewed between December 2010 and July 2011 using qualitative methods. Responses were analysed using a thematic framework. Three ways in which HCWs appraised their behaviour were identified through accounts of IPC policies and practices: (1) attribution of responsibilities, with ambiguity about responsibility for certain IPC practices; (2) prioritization and risk appraisal, which demonstrated a divergence in values attached to some IPC policies and practices; and (3) hierarchy of influence highlighted that traditional clinical roles challenged work relationships. Overall, behaviours are not entirely independent of policy rules, but often an amalgamation of local normative practices, individual preferences and a degree of professional isolation. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  1. Real-Time Measurements and Modelling on Dynamic Behaviour of SonoVue Bubbles Based on Light Scattering Technology

    International Nuclear Information System (INIS)

    Juan, Tu; Rongjue, Wei; Guan, J. F.; Matula, T. J.; Crum, L. A.

    2008-01-01

    The dynamic behaviour of SonoVue microbubbles, a new generation ultrasound contrast agent, is investigated in real time with light scattering method. Highly diluted SonoVue microbubbles are injected into a diluted gel made of xanthan gum and water. The responses of individual SonoVue bubbles to driven ultrasound pulses are measured. Both linear and nonlinear bubble oscillations are observed and the results suggest that SonoVue microbubbles can generate strong nonlinear responses. By fitting the experimental data of individual bubble responses with Sarkar's model, the shell coating parameter of the bubbles and dilatational viscosity is estimated to be 7.0 nm·s·Pa

  2. Dynamic behaviour of TM380 mild steel and Ti6Al4V alloy subjected to blast loading

    CSIR Research Space (South Africa)

    Shoke, Lerato

    2016-10-01

    Full Text Available and Base Metals Development Network Conference 2016, 19-20 October 2016, KwaZulu Natal, Maharani Hotel Dynamic behaviour of TM380 mild steel and Ti6Al4V alloy subjected to blast loading L. Shoke,1* K. Mutombo2, I.M. Snyman1 and T. Sono1 1... Landwards Sciences, Defence Peace Safety and Security (DPSS), 2 Material Sciences and Manufacturing (MSM), Council for Scientific and Industrial Research (CSIR), Pretoria, South Africa Lshoke@csir.co.za Abstract This paper deals...

  3. Experimental and numerical analysis of the dynamic behaviour in tension of an armour steel for applications in defence industry

    Directory of Open Access Journals (Sweden)

    Cadoni Ezio

    2015-01-01

    Full Text Available The dynamic behaviour of armour steel in tension was investigated over a wide range of strain-rates on round specimens. The experiments were carried out by means of a Split Hopkinson Tensile Bar device and by a Hydro Pneumatic Machine. The target strain rate were set at the following six levels: 10−3, 5, 25, 100, 500 and 1000 s−1. Two material models were calibrated and used to replicate the experiments and to simulate blasting event on steel plate. Finally, the two responses are compared.

  4. Experimental and numerical analysis of the dynamic behaviour in tension of an armour steel for applications in defence industry

    Science.gov (United States)

    Cadoni, Ezio; Dotta, Matteo; Forni, Daniele; Riganti, Gianmario; Kaufmann, Hanspeter

    2015-09-01

    The dynamic behaviour of armour steel in tension was investigated over a wide range of strain-rates on round specimens. The experiments were carried out by means of a Split Hopkinson Tensile Bar device and by a Hydro Pneumatic Machine. The target strain rate were set at the following six levels: 10-3, 5, 25, 100, 500 and 1000 s-1. Two material models were calibrated and used to replicate the experiments and to simulate blasting event on steel plate. Finally, the two responses are compared.

  5. Association between REM sleep behaviour disorder and impulse control disorder in patients with Parkinson's disease.

    Science.gov (United States)

    Bellosta Diago, E; Lopez Del Val, L J; Santos Lasaosa, S; López Garcia, E; Viloria Alebesque, A

    2017-10-01

    The relationship between impulse control disorder (ICD) and REM sleep behaviour disorder (RBD) has not yet been clarified, and the literature reports contradictory results. Our purpose is to analyse the association between these 2 disorders and their presence in patients under dopaminergic treatment. A total of 73 patients diagnosed with Parkinson's disease and treated with a single dopamine agonist were included in the study after undergoing clinical assessment and completing the single-question screen for REM sleep behaviour disorder and the short version of the questionnaire for impulsive-compulsive behaviours in Parkinson's disease. Mean age was 68.88 ± 7.758 years. Twenty-six patients (35.6%) were classified as probable-RBD. This group showed a significant association with ICD (P=.001) and had a higher prevalence of non-tremor akinetic rigid syndrome and longer duration of treatment with levodopa and dopamine agonists than the group without probable-RBD. We found a significant correlation between the use of oral dopamine agonists and ICD. Likewise, patients treated with oral dopamine agonists demonstrated a greater tendency toward presenting probable-RBD than patients taking dopamine agonists by other routes; the difference was non-significant. The present study confirms the association between RBD and a higher risk of developing symptoms of ICD in Parkinson's disease. Copyright © 2016 Sociedad Española de Neurología. Publicado por Elsevier España, S.L.U. All rights reserved.

  6. A framework for modelling the behaviour of a process control operator under stress

    International Nuclear Information System (INIS)

    Kan, C-C.F.; Roberts, P.D.; Smith, I.C.

    1990-01-01

    This paper proposes the basis for a framework for modelling effects of stress on the behaviour of a process control plant operator. The qualitative effects of stress on the cognitive processing ability of the operator are discussed. Stress is thought to mainly decrease the reasoning ability of the operator. The operator will experience increased rigidity in problem solving and the narrowing of his attention and perceptual field. At the same time, the operator will be increasingly reluctant in admitting that wrong decisions have been committed. Furthermore, he will revert to skill-based behaviours. The direct consequence of stress on the decision making mechanism of the operator is the selection of inappropriate choice of action. A formal representation of decision errors is proposed and various techniques are suggested for representing various mechanisms for decision error making. The degree of experience possessed by the operator is also an important factor to the operator's tolerance of stress. The framework also allows the experience of the operator to be integrated into the model. Such an operator model can be linked to a plant simulator and the complete behaviour of the plant then be simulated

  7. Compressible dynamic stall control using high momentum microjets

    Science.gov (United States)

    Beahan, James J.; Shih, Chiang; Krothapalli, Anjaneyulu; Kumar, Rajan; Chandrasekhara, Muguru S.

    2014-09-01

    Control of the dynamic stall process of a NACA 0015 airfoil undergoing periodic pitching motion is investigated experimentally at the NASA Ames compressible dynamic stall facility. Multiple microjet nozzles distributed uniformly in the first 12 % chord from the airfoil's leading edge are used for the dynamic stall control. Point diffraction interferometry technique is used to characterize the control effectiveness, both qualitatively and quantitatively. The microjet control has been found to be very effective in suppressing both the emergence of the dynamic stall vortex and the associated massive flow separation at the entire operating range of angles of attack. At the high Mach number ( M = 0.4), the use of microjets appears to eliminate the shock structures that are responsible for triggering the shock-induced separation, establishing the fact that the use of microjets is effective in controlling dynamic stall with a strong compressibility effect. In general, microjet control has an overall positive effect in terms of maintaining leading edge suction pressure and preventing flow separation.

  8. Understanding the dynamical control of animal movement

    Science.gov (United States)

    Edwards, Donald

    2008-03-01

    Over the last 50 years, neurophysiologists have described many neural circuits that transform sensory input into motor commands, while biomechanicians and behavioral biologists have described many patterns of animal movement that occur in response to sensory input. Attempts to link these two have been frustrated by our technical inability to record from the necessary neurons in a freely behaving animal. As a result, we don't know how these neural circuits function in the closed loop context of free behavior, where the sensory and motor context changes on a millisecond time-scale. To address this problem, we have developed a software package, AnimatLab (www.AnimatLab.com), that enables users to reconstruct an animal's body and its relevant neural circuits, to link them at the sensory and motor ends, and through simulation, to test their ability to reproduce appropriate patterns of the animal's movements in a simulated Newtonian world. A Windows-based program, AnimatLab consists of a neural editor, a body editor, a world editor, stimulus and recording facilities, neural and physics engines, and an interactive 3-D graphical display. We have used AnimatLab to study three patterns of behavior: the grasshopper jump, crayfish escape, and crayfish leg movements used in postural control, walking, reaching and grasping. In each instance, the simulation helped identify constraints on both nervous function and biomechanical performance that have provided the basis for new experiments. Colleagues elsewhere have begun to use AnimatLab to study control of paw movements in cats and postural control in humans. We have also used AnimatLab simulations to guide the development of an autonomous hexapod robot in which the neural control circuitry is downloaded to the robot from the test computer.

  9. Dynamics and chaos control of gyrostat satellite

    International Nuclear Information System (INIS)

    Aslanov, Vladimir; Yudintsev, Vadim

    2012-01-01

    Highlights: ► Free dual-spin gyrostat with a small rotor asymmetry is considered. ► Equations in Andoyer-Deprit canonical dimensionless variables are obtained. ► Phase space heteroclinic and homoclinic trajectories are written in closed form. ► Modified Melnikov function is used to construct the control that eliminates chaos. - Abstract: We consider the chaotic motion of the free gyrostat consisting of a platform with a triaxial inertia ellipsoid and a rotor with a small asymmetry with respect to the axis of rotation. Dimensionless equations of motion of the system with perturbations caused by small asymmetries of the rotor are written in Andoyer-Deprit variables. These perturbations lead to separatrix chaos. For gyrostats with different ratios of moments of inertia heteroclinic and homoclinic trajectories are written in closed-form. These trajectories are used for constructing modified Melnikov function, which is used for determine the control that eliminates separatrix chaos. Melnikov function and phase space trajectory are built to show the effectiveness of the control.

  10. Tracing control of chaos for the coupled dynamos dynamical system

    International Nuclear Information System (INIS)

    Wang Xuedi; Tian Lixin

    2004-01-01

    This paper introduces a new method for the coupled dynamos dynamical system, which can be applied to the decision of the chaotic behavior of the system. And research the tracing control of the chaos for the coupled dynamos dynamical system by gradually changing the driving parameter for the chaos. With the different design of controllers, the numerical simulation results show the relation between the chaotic behavior and the changes of the parameter value. Furthermore, the result shows the difference of the controllers. In the mean time, it reveals the process of the orbit's gradual changing with the parameter value

  11. Dynamic modeling, simulation and control of energy generation

    CERN Document Server

    Vepa, Ranjan

    2013-01-01

    This book addresses the core issues involved in the dynamic modeling, simulation and control of a selection of energy systems such as gas turbines, wind turbines, fuel cells and batteries. The principles of modeling and control could be applied to other non-convention methods of energy generation such as solar energy and wave energy.A central feature of Dynamic Modeling, Simulation and Control of Energy Generation is that it brings together diverse topics in thermodynamics, fluid mechanics, heat transfer, electro-chemistry, electrical networks and electrical machines and focuses on their appli

  12. The effect of processing parameters on the dynamic recrystallisation behaviour of API-X70 pipeline steel

    International Nuclear Information System (INIS)

    Al Shahrani, Abdullah; Yazdipour, Nima; Dehghan-Manshadi, Ali; Gazder, Azdiar A.; Cayron, Cyril; Pereloma, Elena V.

    2013-01-01

    The effect of deformation temperature and strain rate on the dynamic recrystallisation (DRX) behaviour of X70 pipeline steel was investigated. DRX parameters such as the critical and peak stresses and strains as well as the deformation activation energy were determined in the temperature range between 925 °C and 1125 °C for strain rates of 0.1, 1 and 5 s −1 . The relationship between the peak stresses and strains with the Zener–Hollomon parameter was determined. The dynamically recrystallised volume fraction was computed as a function of the different temperatures and strain rates. The APRGE software was applied for the first time on electron back-scattering diffraction data of dynamically recrystallised microstructures in order to reconstruct the prior austenite from the as-quenched martensite phase. The dynamically recrystallised flow stress curves and microstructure were also predicted using cellular automata modelling. The results show an earlier onset of DRX with a decrease in strain rate or an increase in deformation temperature. The dynamically recrystallised grain size is also found to decrease with an increase in strain rate and a lowering of deformation temperature

  13. Distributed dynamic simulations of networked control and building performance applications.

    Science.gov (United States)

    Yahiaoui, Azzedine

    2018-02-01

    The use of computer-based automation and control systems for smart sustainable buildings, often so-called Automated Buildings (ABs), has become an effective way to automatically control, optimize, and supervise a wide range of building performance applications over a network while achieving the minimum energy consumption possible, and in doing so generally refers to Building Automation and Control Systems (BACS) architecture. Instead of costly and time-consuming experiments, this paper focuses on using distributed dynamic simulations to analyze the real-time performance of network-based building control systems in ABs and improve the functions of the BACS technology. The paper also presents the development and design of a distributed dynamic simulation environment with the capability of representing the BACS architecture in simulation by run-time coupling two or more different software tools over a network. The application and capability of this new dynamic simulation environment are demonstrated by an experimental design in this paper.

  14. Unhealthy weight control behaviours in adolescent girls: a process model based on self-determination theory

    OpenAIRE

    Thøgersen-Ntoumani, Cecilie; Ntoumanis, Nikos

    2009-01-01

    This study used self-determination theory (Deci, E.L., & Ryan, R.M. (2000). The 'what' and 'why' of goal pursuits: Human needs and the self-determination of behavior. Psychological Inquiry, 11, 227-268.) to examine predictors of body image concerns and unhealthy weight control behaviours in a sample of 350 Greek adolescent girls. A process model was tested which proposed that perceptions of parental autonomy support and two life goals (health and image) would predict adolescents' degree of sa...

  15. Dynamics and control of nuclear power plants

    International Nuclear Information System (INIS)

    Tomsic, M.; Mavko, B.; Aleksic, U.; Stritar, A.; Adrinek, R.

    1977-01-01

    A mathematical model of the power plant with a pressurized water reactor has been prepared and tested. The model is intended for a schematic simulator based on a digital computer. The results of the simulation run for various normal transients are in good agreement with literature data. Equipment for computer control of the experimental reactor TRIGA has been completed. The equipment includes two microcomputers and associated interface circuits. Presently, only data logging is performed. The analyses of random signals on the TRIGA reactor have been continued. Measurements of neutron flux, fuel temperature and cooling water duct have been performed

  16. Multi-Mode Electric Actuator Dynamic Modelling for Missile Fin Control

    Directory of Open Access Journals (Sweden)

    Bhimashankar Gurav

    2017-06-01

    Full Text Available Linear first/second order fin direct current (DC actuator model approximations for missile applications are currently limited to angular position and angular velocity state variables. Furthermore, existing literature with detailed DC motor models is decoupled from the application of interest: tail controller missile lateral acceleration (LATAX performance. This paper aims to integrate a generic DC fin actuator model with dual-mode feedforward and feedback control for tail-controlled missiles in conjunction with the autopilot system design. Moreover, the characteristics of the actuator torque information in relation to the aerodynamic fin loading for given missile trim velocities are also provided. The novelty of this paper is the integration of the missile LATAX autopilot states and actuator states including the motor torque, position and angular velocity. The advantage of such an approach is the parametric analysis and suitability of the fin actuator in relation to the missile lateral acceleration dynamic behaviour.

  17. Threshold behaviour in hydrological systems as (human geo-ecosystems: manifestations, controls, implications

    Directory of Open Access Journals (Sweden)

    M. Sivapalan

    2009-07-01

    Full Text Available In this paper we review threshold behaviour in environmental systems, which are often associated with the onset of floods, contamination and erosion events, and other degenerative processes. Key objectives of this review are to a suggest indicators for detecting threshold behavior, b discuss their implications for predictability, c distinguish different forms of threshold behavior and their underlying controls, and d hypothesise on possible reasons for why threshold behaviour might occur. Threshold behaviour involves a fast qualitative change of either a single process or the response of a system. For elementary phenomena this switch occurs when boundary conditions (e.g., energy inputs or system states as expressed by dimensionless quantities (e.g. the Reynolds number exceed threshold values. Mixing, water movement or depletion of thermodynamic gradients becomes much more efficient as a result. Intermittency is a very good indicator for detecting event scale threshold behavior in hydrological systems. Predictability of intermittent processes/system responses is inherently low for combinations of systems states and/or boundary conditions that push the system close to a threshold. Post hoc identification of "cause-effect relations" to explain when the system became critical is inherently difficult because of our limited ability to perform observations under controlled identical experimental conditions. In this review, we distinguish three forms of threshold behavior. The first one is threshold behavior at the process level that is controlled by the interplay of local soil characteristics and states, vegetation and the rainfall forcing. Overland flow formation, particle detachment and preferential flow are examples of this. The second form of threshold behaviour is the response of systems of intermediate complexity – e.g., catchment runoff response and sediment yield – governed by the redistribution of water and sediments in space and time

  18. Standardizing commercial CPUE data in monitoring stock dynamics: Accounting for targeting behaviour in mixed fisheries

    NARCIS (Netherlands)

    Quirijns, F.J.; Poos, J.J.; Rijnsdorp, A.D.

    2008-01-01

    Catch per unit effort (CPUE) is commonly used as an indicator for monitoring developments in stock size. To ensure proportionality between average CPUE and total stock size, two processes that should be accounted for are the degree of targeting behaviour of the fleet and the management-induced

  19. The Dynamics of Chinese Face Mechanisms and Classroom Behaviour: A Case Study

    Science.gov (United States)

    Wu, Xiaoxin

    2009-01-01

    Research on cross-cultural psychology, anthropology and sociology reveals that the impact of face on social interactions is both pervasive and powerful in Asia. Face, however, has not gained general acceptance as an important theoretical concept in the literature on Asian (Chinese in particular) classroom behaviour and management. This article…

  20. Association between tobacco control policies and smoking behaviour among adolescents in 29 European countries

    DEFF Research Database (Denmark)

    Hublet, Anne; Schmid, Holger; Clays, Els

    2009-01-01

    AIMS: To investigate the associations between well-known, cost-effective tobacco control policies at country level and smoking prevalence among 15-year-old adolescents. DESIGN: Multi-level modelling based on the 2005-06 Health Behaviour in School-aged Children Study, a cross-national study...... at individual level, and with country-level variables from the Tobacco Control Scale and published country-level databases. SETTING: Twenty-nine European countries. PARTICIPANTS: A total of 25 599 boys and 26 509 girls. MAIN OUTCOME MEASURES: Self-reported regular smoking defined as at least weekly smoking...... vending machines) = -0.372, P = 0.06]. CONCLUSIONS: For boys, some of the currently recommended tobacco control policies may help to reduce smoking prevalence. However, the model is less suitable for girls, indicating gender differences in the potential efficacy of smoking policies. Future research should...

  1. Dynamic Mechanical Analysis and Three-Body Abrasive Wear Behaviour of Thermoplastic Copolyester Elastomer Composites

    Directory of Open Access Journals (Sweden)

    Hemanth Rajashekaraiah

    2014-01-01

    Full Text Available Various amounts of short fibers (glass and carbon and particulate fillers like polytetrafluoroethylene (PTFE, silicon carbide (SiC, and alumina (Al2O3 were systematically introduced into the thermoplastic copolyester elastomer (TCE matrix for reinforcement purpose. The mechanical properties such as storage modulus, loss modulus, and Tan δ by dynamic mechanical analysis (DMA and three-body abrasive wear performance on a dry sand rubber wheel abrasion tester have been investigated. For abrasive wear study, the experiments were planned according to L27 orthogonal array by considering three factors and three levels. The complex moduli for TCE hybrid composites were pushed to a higher level relative to the TCE filled PTFE composite. At lower temperatures (in the glassy region, the storage modulus increases with increase in wt.% of reinforcement (fiber + fillers and the value is maximum for the composite with 40 wt.% reinforcement. The loss modulus and damping peaks were also found to be higher by the incorporation of SiC and Al2O3 microfillers. The routine abrasive wear test results indicated that TCE filled PTFE composite exhibited better abrasion resistance. Improvements in the abrasion resistance, however, have not been achieved by short-fiber and particlaute filler reinforcements. From the Taguchi’s experimental findings, optimal combination of control factors were obtained for minimum wear volume and also predictive correlations were proposed. Further, the worn surface morphology of the samples was discussed.

  2. Study on dynamic lifting characteristics of control rod drive mechanism

    International Nuclear Information System (INIS)

    Shen Xiaoyao

    2012-01-01

    Based on the equations of the electric circuit and the magnetic circuit and analysis of the dynamic lifting process for the control rod drive mechanism (CRDM), coupled magnetic-electric-mechanical equations both for the static status and the dynamic status are derived. The analytical method is utilized to obtain the current and the time when the lift starts. The numerical simulation method of dynamic analysis recommended by ASME Code is utilized to simulate the dynamic lifting process of CRDM, and the dynamic features of the system with different design gaps are studied. Conclusions are drawn as: (1) the lifting-start time increases with the design gap, and the time for the lifting process is longer with larger gaps; (2) the lifting velocity increases with time; (3) the lifting acceleration increases with time, and with smaller gaps, the impact acceleration is larger. (author)

  3. Experimental and numerical analysis concerning the behaviour of OL50 steel grade specimens coated with polyurea layer under dynamics loadings

    Directory of Open Access Journals (Sweden)

    Bucur Florina

    2015-01-01

    Full Text Available This study refers to an experimental and numerical evaluation of a polyurea coating layer influence on the dynamic behaviour of OL50 specimens. Mechanical quasi-static and dynamic tensile tests were performed in axial loading conditions, for 2 mm steel plate specimens. Several metallic specimens have been previously coated with 1.5 mm and 3 mm respectively thickness polyurea layer and tested in traction. The findings results indicate that the presence of polyurea changes the loading pattern of metallic material in the necking area. In terms of polyurea coated metal specimens fracture, there was clearly observed a change of fracture limit. One possible explanation of this phenomenon is the modification of triaxiality state in the necking zone, fact proven by the numerical simulations. Test results indicate that the presence of polyurea layer delays the necking onset phenomenon which precedes the OL50 metallic specimen fracture.

  4. Group performance and group learning at dynamic system control tasks

    International Nuclear Information System (INIS)

    Drewes, Sylvana

    2013-01-01

    Proper management of dynamic systems (e.g. cooling systems of nuclear power plants or production and warehousing) is important to ensure public safety and economic success. So far, research has provided broad evidence for systematic shortcomings in individuals' control performance of dynamic systems. This research aims to investigate whether groups manifest synergy (Larson, 2010) and outperform individuals and if so, what processes lead to these performance advantages. In three experiments - including simulations of a nuclear power plant and a business setting - I compare the control performance of three-person-groups to the average individual performance and to nominal groups (N = 105 groups per experiment). The nominal group condition captures the statistical advantage of aggregated group judgements not due to social interaction. First, results show a superior performance of groups compared to individuals. Second, a meta-analysis across all three experiments shows interaction-based process gains in dynamic control tasks: Interacting groups outperform the average individual performance as well as the nominal group performance. Third, group interaction leads to stable individual improvements of group members that exceed practice effects. In sum, these results provide the first unequivocal evidence for interaction-based performance gains of groups in dynamic control tasks and imply that employers should rely on groups to provide opportunities for individual learning and to foster dynamic system control at its best.

  5. Dynamical Aperture Control in Accelerator Lattices With Multipole Potentials

    CERN Document Server

    Morozov, I

    2017-01-01

    We develop tools for symbolic representation of a non-linear accelerator model and analytical methods for description of non-linear dynamics. Information relevant to the dynamic aperture (DA) is then obtained from this model and can be used for indirect DA control or as a complement to direct numerical optimization. We apply two analytical methods and use multipole magnets to satisfy derived analytical constraints. The accelerator model is represented as a product of unperturbed and perturbed exponential operators with the exponent of the perturbed operator given as a power series in the perturbation parameter. Normal forms can be applied to this representation and the lattice parameters are used to control the normal form Hamiltonian and normal form transformation. Hamiltonian control is used to compute a control term or controlled operator. Lattice parameters are then fitted to satisfy the imposed control constraints. Theoretical results, as well as illustrative examples, are presented.

  6. Offset Free Tracking Predictive Control Based on Dynamic PLS Framework

    Directory of Open Access Journals (Sweden)

    Jin Xin

    2017-10-01

    Full Text Available This paper develops an offset free tracking model predictive control based on a dynamic partial least square (PLS framework. First, state space model is used as the inner model of PLS to describe the dynamic system, where subspace identification method is used to identify the inner model. Based on the obtained model, multiple independent model predictive control (MPC controllers are designed. Due to the decoupling character of PLS, these controllers are running separately, which is suitable for distributed control framework. In addition, the increment of inner model output is considered in the cost function of MPC, which involves integral action in the controller. Hence, the offset free tracking performance is guaranteed. The results of an industry background simulation demonstrate the effectiveness of proposed method.

  7. Adaptive Dynamic Programming for Control Algorithms and Stability

    CERN Document Server

    Zhang, Huaguang; Luo, Yanhong; Wang, Ding

    2013-01-01

    There are many methods of stable controller design for nonlinear systems. In seeking to go beyond the minimum requirement of stability, Adaptive Dynamic Programming for Control approaches the challenging topic of optimal control for nonlinear systems using the tools of  adaptive dynamic programming (ADP). The range of systems treated is extensive; affine, switched, singularly perturbed and time-delay nonlinear systems are discussed as are the uses of neural networks and techniques of value and policy iteration. The text features three main aspects of ADP in which the methods proposed for stabilization and for tracking and games benefit from the incorporation of optimal control methods: • infinite-horizon control for which the difficulty of solving partial differential Hamilton–Jacobi–Bellman equations directly is overcome, and  proof provided that the iterative value function updating sequence converges to the infimum of all the value functions obtained by admissible control law sequences; • finite-...

  8. Position Control of Linear Synchronous Motor Drives with Exploitation of Forced Dynamics Control Principles

    Directory of Open Access Journals (Sweden)

    Jan Vittek

    2004-01-01

    Full Text Available Closed-loop position control of mechanisms directly driven by linear synchronous motors with permanent magnets is presented. The control strategy is based on forced dynamic control, which is a form of feedback linearisation, yielding a non-liner multivariable control law to obtain a prescribed linear speed dynamics together with the vector control condition of mutal orthogonality between the stator current and magnetic flux vectors (assuming perfect estimates of the plant parameters. Outer position control loop is closed via simple feedback with proportional gain. Simulations of the design control sysstem, including the drive with power electronic switching, predict the intended drive performance.

  9. Dynamic Evolution Analysis of Stock Price Fluctuation and Its Control

    Directory of Open Access Journals (Sweden)

    Yuhua Xu

    2018-01-01

    Full Text Available This paper studies a simple dynamical system of stock price fluctuation time series based on the rule of stock market. When the stock price fluctuation system is disturbed by external excitations, the system exhibits obviously chaotic phenomena, and its basic dynamic properties are analyzed. At the same time, a new fixed-time convergence theorem is proposed for achieving fixed-time control of stock price fluctuation system. Finally, the effectiveness of the method is verified by numerical simulation.

  10. Dynamic behaviour of the icosahedral Al–Pd–Mn quasicrystal with a Griffith crack

    International Nuclear Information System (INIS)

    Xiao-Fang, Wang; Ai-Yu, Zhu; Tian-You, Fan

    2009-01-01

    The dynamic response of an icosahedral Al–Pd–Mn quasicrystal with a Griffith crack to impact loading is investigated in this paper. The elastohydrodynamic model for the wave propagation and diffusion together with their interaction is adopted. Numerical results of stress, displacement and dynamic stress intensity factors are obtained by using the finite difference method. The effects of wave propagation, diffusion and phonon–phason coupling on the quasicrystal in the dynamic process are discussed in detail, where the phason dynamics is explored particularly. (condensed matter: structure, thermal and mechanical properties)

  11. Dynamics and control of Lorentz-augmented spacecraft relative motion

    CERN Document Server

    Yan, Ye; Yang, Yueneng

    2017-01-01

    This book develops a dynamical model of the orbital motion of Lorentz spacecraft in both unperturbed and J2-perturbed environments. It explicitly discusses three kinds of typical space missions involving relative orbital control: spacecraft hovering, rendezvous, and formation flying. Subsequently, it puts forward designs for both open-loop and closed-loop control schemes propelled or augmented by the geomagnetic Lorentz force. These control schemes are entirely novel and represent a significantly departure from previous approaches.

  12. Using dynamic input allocation for elongation control at FTU

    International Nuclear Information System (INIS)

    Boncagni, L.; Galeani, S.; Granucci, G.; Varano, G.; Vitale, V.; Zaccarian, L.

    2010-01-01

    In this paper we exploit the dynamic allocation scheme for input redundant control systems proposed in to achieve elongation control on FTU (Frascati Tokamak Upgrade). The scheme first serves as a means for regulating the current in the F coils. Then, due to the quasi-static relationship between the plasma elongation and the F coils current, elongation control is achieved by suitably generalizing the allocation scheme. Both simulation and experimental results are reported.

  13. Isolated sub-100-attosecond pulse generation via controlling electron dynamics

    OpenAIRE

    Lan, Pengfei; Lu, Peixiang; Cao, Wei; Li, Yuhua; Wang, Xinlin

    2007-01-01

    A new method to coherently control the electron dynamics is proposed using a few-cycle laser pulse in combination with a controlling field. It is shown that this method not only broadens the attosecond pulse bandwidth, but also reduces the chirp, then an isolated 80-as pulse is straightforwardly obtained and even shorter pulse is achievable by increasing the intensity of the controlling field. Such ultrashort pulses allow one to investigate ultrafast electronic processes which have never be a...

  14. Dynamic stability control in forward falls: postural corrections after muscle fatigue in young and older adults.

    Science.gov (United States)

    Mademli, Lida; Arampatzis, Adamantios; Karamanidis, Kiros

    2008-06-01

    Many studies report that muscle strength loss may alter the human system's capacity to generate rapid force for balance corrections after perturbations, leading to deficient recovery behaviours. Yet little is known regarding the effect of modifications in the neuromuscular system induced by fatigue on dynamic stability control during postural perturbations. This study investigates the effect of muscle strength decline induced by fatiguing contractions on the dynamic stability control of young and older adults during forward falls. Eleven young and eleven older male adults had to regain balance after sudden falls before and after submaximal fatiguing knee extension-flexion contractions. Young subjects had a higher margin of stability than older ones before and after the fatiguing task. This reflects their enhanced ability in using mechanisms for maintaining dynamic stability (i.e. a greater base of support). The margin of stability, the boundary of the base of support and the position of the extrapolated centre of mass, remained unaffected by the reduction in muscle strength induced by the fatiguing contractions, indicating an appropriate adjustment of the motor commands to compensate the deficit in muscle strength. Both young and older adults were able to counteract the decreased horizontal ground reaction forces after the fatiguing task by flexing their knee to a greater extent, leading to similar decreases in the horizontal velocity of centre of mass as in the pre fatigue condition. The results demonstrate the ability of the central nervous system to rapidly modify the execution of postural corrections including mechanisms for maintaining dynamic stability.

  15. Diagonal recurrent neural network based adaptive control of nonlinear dynamical systems using lyapunov stability criterion.

    Science.gov (United States)

    Kumar, Rajesh; Srivastava, Smriti; Gupta, J R P

    2017-03-01

    In this paper adaptive control of nonlinear dynamical systems using diagonal recurrent neural network (DRNN) is proposed. The structure of DRNN is a modification of fully connected recurrent neural network (FCRNN). Presence of self-recurrent neurons in the hidden layer of DRNN gives it an ability to capture the dynamic behaviour of the nonlinear plant under consideration (to be controlled). To ensure stability, update rules are developed using lyapunov stability criterion. These rules are then used for adjusting the various parameters of DRNN. The responses of plants obtained with DRNN are compared with those obtained when multi-layer feed forward neural network (MLFFNN) is used as a controller. Also, in example 4, FCRNN is also investigated and compared with DRNN and MLFFNN. Robustness of the proposed control scheme is also tested against parameter variations and disturbance signals. Four simulation examples including one-link robotic manipulator and inverted pendulum are considered on which the proposed controller is applied. The results so obtained show the superiority of DRNN over MLFFNN as a controller. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  16. Cell fate reprogramming by control of intracellular network dynamics

    Science.gov (United States)

    Zanudo, Jorge G. T.; Albert, Reka

    Identifying control strategies for biological networks is paramount for practical applications that involve reprogramming a cell's fate, such as disease therapeutics and stem cell reprogramming. Although the topic of controlling the dynamics of a system has a long history in control theory, most of this work is not directly applicable to intracellular networks. Here we present a network control method that integrates the structural and functional information available for intracellular networks to predict control targets. Formulated in a logical dynamic scheme, our control method takes advantage of certain function-dependent network components and their relation to steady states in order to identify control targets, which are guaranteed to drive any initial state to the target state with 100% effectiveness and need to be applied only transiently for the system to reach and stay in the desired state. We illustrate our method's potential to find intervention targets for cancer treatment and cell differentiation by applying it to a leukemia signaling network and to the network controlling the differentiation of T cells. We find that the predicted control targets are effective in a broad dynamic framework. Moreover, several of the predicted interventions are supported by experiments. This work was supported by NSF Grant PHY 1205840.

  17. Frequency of impulse control behaviours associated with dopaminergic therapy in restless legs syndrome

    Directory of Open Access Journals (Sweden)

    Reiff Julia

    2011-09-01

    Full Text Available Abstract Background Low doses of dopamine agonists (DA and levodopa are effective in the treatment of restless legs syndrome (RLS. A range of impulse control and compulsive behaviours (ICBs have been reported following the use of DAs and levodopa in patients with Parkinson's disease. With this study we sought to assess the cross-sectional prevalence of impulse control behaviours (ICBs in restless legs syndrome (RLS and to determine factors associated with ICBs in a population cohort in Germany. Methods Several questionnaires based on validated and previously used instruments for assessment of ICBs were mailed out to patients being treated for RLS. Final diagnoses of ICBs were based on stringent diagnostic criteria after psychiatric interviews were performed. Results 10/140 RLS patients of a clinical cohort (7.1% were finally diagnosed with ICBs, 8 of 10 on dopamine agonist (DA therapy, 2 of 10 on levodopa. 8 of the 10 affected patients showed more than one type of abnormal behaviour. Among those who responded to the questionnaires 6/140 [4.3%] revealed binge eating, 5/140 [3.6%] compulsive shopping, 3/140 [2.1%] pathological gambling, 3/140 [2.1%] punding, and 2/140 [1.4%] hypersexuality in psychiatric assessments. Among those who did not respond to questionnaires, 32 were randomly selected and interviewed: only 1 patient showed positive criteria of ICBs with compulsive shopping and binge eating. ICBs were associated with higher DA dose (p = 0.001, younger RLS onset (p = 0.04, history of experimental drug use (p = 0.002, female gender (p = 0.04 and a family history of gambling disorders (p = 0.02, which accounted for 52% of the risk variance. Conclusion RLS patients treated with dopaminergic agents and dopamine agonists in particular, should be forewarned of potential side effects. A careful history of risk factors should be taken.

  18. Stress Analysis and Fatigue Behaviour of PTFE-Bronze Layered Journal Bearing under Real-Time Dynamic Loading

    Science.gov (United States)

    Duman, M. S.; Kaplan, E.; Cuvalcı, O.

    2018-01-01

    The present paper is based on experimental studies and numerical simulations on the surface fatigue failure of the PTFE-bronze layered journal bearings under real-time loading. ‘Permaglide Plain Bearings P10’ type journal bearings were experimentally tested under different real time dynamic loadings by using real time journal bearing test system in our laboratory. The journal bearing consists of a PTFE-bronze layer approximately 0.32 mm thick on the steel support layer with 2.18 mm thick. Two different approaches have been considered with in experiments: (i) under real- time constant loading with varying bearing widths, (ii) under different real-time loadings at constant bearing widths. Fatigue regions, micro-crack dispersion and stress distributions occurred at the journal bearing were experimentally and theoretically investigated. The relation between fatigue region and pressure distributions were investigated by determining the circumferential pressure distribution under real-time dynamic loadings for the position of every 10° crank angles. In the theoretical part; stress and deformation distributions at the surface of the journal bearing analysed by using finite element methods to determine the relationship between stress and fatigue behaviour. As a result of this study, the maximum oil pressure and fatigue cracks were observed in the most heavily loaded regions of the bearing surface. Experimental results show that PTFE-Bronze layered journal bearings fatigue behaviour is better than the bearings include white metal alloy.

  19. Material-controlled dynamic vacuum insulation

    Science.gov (United States)

    Benson, D.K.; Potter, T.F.

    1996-10-08

    A compact vacuum insulation panel is described comprising a chamber enclosed by two sheets of metal, glass-like spaces disposed in the chamber between the sidewalls, and a high-grade vacuum in the chamber includes apparatus and methods for enabling and disabling, or turning ``on`` and ``off`` the thermal insulating capability of the panel. One type of enabling and disabling apparatus and method includes a metal hydride for releasing hydrogen gas into the chamber in response to heat, and a hydrogen grate between the metal hydride and the chamber for selectively preventing and allowing return of the hydrogen gas to the metal hydride. Another type of enabling and disabling apparatus and method includes a variable emissivity coating on the sheets of metal in which the emissivity is controllably variable by heat or electricity. Still another type of enabling and disabling apparatus and method includes metal-to-metal contact devices that can be actuated to establish or break metal-to-metal heat paths or thermal short circuits between the metal sidewalls. 25 figs.

  20. Radiation-controlled dynamic vacuum insulation

    Science.gov (United States)

    Benson, D.K.; Potter, T.F.

    1995-07-18

    A compact vacuum insulation panel is described comprising a chamber enclosed by two sheets of metal, glass-like spaces disposed in the chamber between the sidewalls, and a high-grade vacuum in the chamber that includes apparatus and methods for enabling and disabling, or turning ``on`` and ``off`` the thermal insulating capability of the panel. One type of enabling and disabling apparatus and method includes a metal hydride for releasing hydrogen gas into the chamber in response to heat, and a hydrogen grate between the metal hydride and the chamber for selectively preventing and allowing return of the hydrogen gas to the metal hydride. Another type of enabling and disabling apparatus and method includes a variable emissivity coating on the sheets of metal in which the emissivity is controllably variable by heat or electricity. Still another type of enabling and disabling apparatus and method includes metal-to-metal contact devices that can be actuated to establish or break metal-to-metal heat paths or thermal short circuits between the metal sidewalls. 25 figs.